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* [pushed][PATCH 2/7] Clone remote breakpoints
  2015-05-12 17:28 [pushed][PATCH 1/7] Identify remote fork event support Don Breazeal
  2015-05-12 17:28 ` [pushed][PATCH 3/7] Extended-remote Linux follow fork Don Breazeal
@ 2015-05-12 17:28 ` Don Breazeal
  2015-05-12 17:29 ` [pushed][PATCH 6/7] Extended-remote fork catch Don Breazeal
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 13+ messages in thread
From: Don Breazeal @ 2015-05-12 17:28 UTC (permalink / raw)
  To: gdb-patches

This is the version of the patch that I pushed.
Thanks
--Don


This patch implements gdbserver routines to clone the breakpoint lists of a
process, duplicating them for another process.  In gdbserver, each process
maintains its own independent breakpoint list.  When a fork call creates a
child, all of the breakpoints currently inserted in the parent process are
also inserted in the child process, but there is nothing to describe them
in the data structures related to the child.  The child must have a
breakpoint list describing them so that they can be removed (if detaching)
or recognized (if following).  Implementation is a mechanical process of
just cloning the lists in several new functions in gdbserver/mem-break.c.

Tested by building, since none of the new functions are called yet.  This
was tested with another patch in the series that implements follow-fork.

gdb/gdbserver/ChangeLog:

        * mem-break.c (APPEND_TO_LIST): Define macro.
        (clone_agent_expr): New function.
        (clone_one_breakpoint): New function.
        (clone_all_breakpoints): New function.
        * mem-break.h: Declare new functions.
---
 gdb/gdbserver/ChangeLog   |   8 ++++
 gdb/gdbserver/mem-break.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++
 gdb/gdbserver/mem-break.h |   6 +++
 3 files changed, 119 insertions(+)

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index a37051d..73788ec 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,13 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* mem-break.c (APPEND_TO_LIST): Define macro.
+	(clone_agent_expr): New function.
+	(clone_one_breakpoint): New function.
+	(clone_all_breakpoints): New function.
+	* mem-break.h: Declare new functions.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* linux-low.c (linux_supports_fork_events): New function.
 	(linux_supports_vfork_events): New function.
 	(linux_target_ops): Initialize new structure members.
diff --git a/gdb/gdbserver/mem-break.c b/gdb/gdbserver/mem-break.c
index 70fab2e..d1b66bf 100644
--- a/gdb/gdbserver/mem-break.c
+++ b/gdb/gdbserver/mem-break.c
@@ -28,6 +28,24 @@ int breakpoint_len;
 
 #define MAX_BREAKPOINT_LEN 8
 
+/* Helper macro used in loops that append multiple items to a singly-linked
+   list instead of inserting items at the head of the list, as, say, in the
+   breakpoint lists.  LISTPP is a pointer to the pointer that is the head of
+   the new list.  ITEMP is a pointer to the item to be added to the list.
+   TAILP must be defined to be the same type as ITEMP, and initialized to
+   NULL.  */
+
+#define APPEND_TO_LIST(listpp, itemp, tailp) \
+	  do \
+	    { \
+	      if ((tailp) == NULL) \
+		*(listpp) = (itemp); \
+	      else \
+		(tailp)->next = (itemp); \
+	      (tailp) = (itemp); \
+	    } \
+	  while (0)
+
 /* GDB will never try to install multiple breakpoints at the same
    address.  However, we can see GDB requesting to insert a breakpoint
    at an address is had already inserted one previously in a few
@@ -1913,3 +1931,90 @@ free_all_breakpoints (struct process_info *proc)
   while (proc->breakpoints)
     delete_breakpoint_1 (proc, proc->breakpoints);
 }
+
+/* Clone an agent expression.  */
+
+static struct agent_expr *
+clone_agent_expr (const struct agent_expr *src_ax)
+{
+  struct agent_expr *ax;
+
+  ax = xcalloc (1, sizeof (*ax));
+  ax->length = src_ax->length;
+  ax->bytes = xcalloc (ax->length, 1);
+  memcpy (ax->bytes, src_ax->bytes, ax->length);
+  return ax;
+}
+
+/* Deep-copy the contents of one breakpoint to another.  */
+
+static struct breakpoint *
+clone_one_breakpoint (const struct breakpoint *src)
+{
+  struct breakpoint *dest;
+  struct raw_breakpoint *dest_raw;
+  struct point_cond_list *current_cond;
+  struct point_cond_list *new_cond;
+  struct point_cond_list *cond_tail = NULL;
+  struct point_command_list *current_cmd;
+  struct point_command_list *new_cmd;
+  struct point_command_list *cmd_tail = NULL;
+
+  /* Clone the raw breakpoint.  */
+  dest_raw = xcalloc (1, sizeof (*dest_raw));
+  dest_raw->raw_type = src->raw->raw_type;
+  dest_raw->refcount = src->raw->refcount;
+  dest_raw->pc = src->raw->pc;
+  dest_raw->size = src->raw->size;
+  memcpy (dest_raw->old_data, src->raw->old_data, MAX_BREAKPOINT_LEN);
+  dest_raw->inserted = src->raw->inserted;
+
+  /* Clone the high-level breakpoint.  */
+  dest = xcalloc (1, sizeof (*dest));
+  dest->type = src->type;
+  dest->raw = dest_raw;
+  dest->handler = src->handler;
+
+  /* Clone the condition list.  */
+  for (current_cond = src->cond_list; current_cond != NULL;
+       current_cond = current_cond->next)
+    {
+      new_cond = xcalloc (1, sizeof (*new_cond));
+      new_cond->cond = clone_agent_expr (current_cond->cond);
+      APPEND_TO_LIST (&dest->cond_list, new_cond, cond_tail);
+    }
+
+  /* Clone the command list.  */
+  for (current_cmd = src->command_list; current_cmd != NULL;
+       current_cmd = current_cmd->next)
+    {
+      new_cmd = xcalloc (1, sizeof (*new_cmd));
+      new_cmd->cmd = clone_agent_expr (current_cmd->cmd);
+      new_cmd->persistence = current_cmd->persistence;
+      APPEND_TO_LIST (&dest->command_list, new_cmd, cmd_tail);
+    }
+
+  return dest;
+}
+
+/* Create a new breakpoint list NEW_LIST that is a copy of the
+   list starting at SRC_LIST.  Create the corresponding new
+   raw_breakpoint list NEW_RAW_LIST as well.  */
+
+void
+clone_all_breakpoints (struct breakpoint **new_list,
+		       struct raw_breakpoint **new_raw_list,
+		       const struct breakpoint *src_list)
+{
+  const struct breakpoint *bp;
+  struct breakpoint *new_bkpt;
+  struct breakpoint *bkpt_tail = NULL;
+  struct raw_breakpoint *raw_bkpt_tail = NULL;
+
+  for (bp = src_list; bp != NULL; bp = bp->next)
+    {
+      new_bkpt = clone_one_breakpoint (bp);
+      APPEND_TO_LIST (new_list, new_bkpt, bkpt_tail);
+      APPEND_TO_LIST (new_raw_list, new_bkpt->raw, raw_bkpt_tail);
+    }
+}
diff --git a/gdb/gdbserver/mem-break.h b/gdb/gdbserver/mem-break.h
index 8b010c1..b5a3208 100644
--- a/gdb/gdbserver/mem-break.h
+++ b/gdb/gdbserver/mem-break.h
@@ -253,4 +253,10 @@ int insert_memory_breakpoint (struct raw_breakpoint *bp);
 
 int remove_memory_breakpoint (struct raw_breakpoint *bp);
 
+/* Create a new breakpoint list NEW_BKPT_LIST that is a copy of SRC.  */
+
+void clone_all_breakpoints (struct breakpoint **new_bkpt_list,
+			    struct raw_breakpoint **new_raw_bkpt_list,
+			    const struct breakpoint *src);
+
 #endif /* MEM_BREAK_H */
-- 
1.8.1.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [pushed][PATCH 3/7] Extended-remote Linux follow fork
  2015-05-12 17:28 [pushed][PATCH 1/7] Identify remote fork event support Don Breazeal
@ 2015-05-12 17:28 ` Don Breazeal
  2015-05-12 17:28 ` [pushed][PATCH 2/7] Clone remote breakpoints Don Breazeal
                   ` (4 subsequent siblings)
  5 siblings, 0 replies; 13+ messages in thread
From: Don Breazeal @ 2015-05-12 17:28 UTC (permalink / raw)
  To: gdb-patches

This is the version of the patch that I pushed.
Thanks
--Don


This patch implements basic support for follow-fork and detach-on-fork on
extended-remote Linux targets.  Only 'fork' is supported in this patch;
'vfork' support is added n a subsequent patch.  This patch depends on
the previous patches in the patch series.

Sufficient extended-remote functionality has been implemented here to pass
gdb.base/multi-forks.exp, as well as gdb.base/foll-fork.exp with the
catchpoint tests commented out.  Some other fork tests fail with this
patch because it doesn't provide the architecture support needed for
watchpoint inheritance or fork catchpoints.

The implementation follows the same general structure as for the native
implementation as much as possible.

This implementation includes:
 * enabling fork events in linux-low.c in initialize_low and
   linux_enable_extended_features

 * handling fork events in gdbserver/linux-low.c:handle_extended_wait

   - when a fork event occurs in gdbserver, we must do the full creation
     of the new process, thread, lwp, and breakpoint lists.  This is
     required whether or not the new child is destined to be
     detached-on-fork, because GDB will make target calls that require all
     the structures.  In particular we need the breakpoint lists in order
     to remove the breakpoints from a detaching child.  If we are not
     detaching the child we will need all these structures anyway.

   - as part of this event handling we store the target_waitstatus in a new
     member of the parent lwp_info structure, 'waitstatus'.  This
     is used to store extended event information for reporting to GDB.

   - handle_extended_wait is given a return value, denoting whether the
     handled event should be reported to GDB.  Previously it had only
     handled clone events, which were never reported.

 * using a new predicate in gdbserver to control handling of the fork event
   (and eventually all extended events) in linux_wait_1.  The predicate,
   extended_event_reported, checks a target_waitstatus.kind for an
   extended ptrace event.

 * implementing a new RSP 'T' Stop Reply Packet stop reason: "fork", in
   gdbserver/remote-utils.c and remote.c.

 * implementing new target and RSP support for target_follow_fork with
   target extended-remote.  (The RSP components were actually defined in
   patch 1, but they see their first use here).

   - remote target routine remote_follow_fork, which just sends the 'D;pid'
     detach packet to detach the new fork child cleanly.  We can't just
     call target_detach because the data structures for the forked child
     have not been allocated on the host side.

Tested on x64 Ubuntu Lucid, native, remote, extended-remote.

gdb/gdbserver/ChangeLog:

        * linux-low.c (handle_extended_wait): Implement return value,
        rename argument 'event_child' to 'event_lwp', handle
        PTRACE_EVENT_FORK, call internal_error for unrecognized event.
        (linux_low_ptrace_options): New function.
        (linux_low_filter_event): Call linux_low_ptrace_options,
        use different argument fo linux_enable_event_reporting,
        use return value from handle_extended_wait.
        (extended_event_reported): New function.
        (linux_wait_1): Call extended_event_reported and set
        status to report fork events.
        (linux_write_memory): Add pid to debug message.
        (reset_lwp_ptrace_options_callback): New function.
        (linux_handle_new_gdb_connection): New function.
        (linux_target_ops): Initialize new structure member.
        * linux-low.h (struct lwp_info) <waitstatus>: New member.
        * lynx-low.c: Initialize new structure member.
        * remote-utils.c (prepare_resume_reply): Implement stop reason
        "fork" for "T" stop message.
        * server.c (handle_query): Call handle_new_gdb_connection.
        * server.h (report_fork_events): Declare global flag.
        * target.h (struct target_ops) <handle_new_gdb_connection>:
        New member.
        (target_handle_new_gdb_connection): New macro.
        * win32-low.c: Initialize new structure member.

gdb/ChangeLog:

        * linux-nat.c (linux_nat_ptrace_options): New function.
        (linux_init_ptrace, wait_lwp, linux_nat_filter_event):
        Call linux_nat_ptrace_options and use different argument to
        linux_enable_event_reporting.
        (_initialize_linux_nat): Delete call to
        linux_ptrace_set_additional_flags.
        * nat/linux-ptrace.c (current_ptrace_options): Rename to
        supported_ptrace_options.
        (additional_flags): Delete variable.
        (linux_check_ptrace_features): Use supported_ptrace_options.
        (linux_test_for_tracesysgood, linux_test_for_tracefork):
        Likewise, and remove additional_flags check.
        (linux_enable_event_reporting): Change 'attached' argument to
        'options'.  Use supported_ptrace_options.
        (ptrace_supports_feature): Change comment.  Use
        supported_ptrace_options.
        (linux_ptrace_set_additional_flags): Delete function.
        * nat/linux-ptrace.h (linux_ptrace_set_additional_flags):
        Delete function prototype.
        * remote.c (remote_fork_event_p): New function.
        (remote_detach_pid): New function.
        (remote_detach_1): Call remote_detach_pid, don't mourn inferior
        if doing detach-on-fork.
        (remote_follow_fork): New function.
        (remote_parse_stop_reply): Handle new "T" stop reason "fork".
        (remote_pid_to_str): Print "process" strings for pid/0/0 ptids.
        (init_extended_remote_ops): Initialize to_follow_fork.
---
 gdb/ChangeLog                |  30 ++++++++
 gdb/gdbserver/ChangeLog      |  27 +++++++
 gdb/gdbserver/linux-low.c    | 180 +++++++++++++++++++++++++++++++++++++++----
 gdb/gdbserver/linux-low.h    |   4 +
 gdb/gdbserver/lynx-low.c     |   1 +
 gdb/gdbserver/remote-utils.c |  14 +++-
 gdb/gdbserver/server.c       |   3 +
 gdb/gdbserver/server.h       |   1 +
 gdb/gdbserver/target.h       |   7 ++
 gdb/gdbserver/win32-low.c    |   1 +
 gdb/linux-nat.c              |  37 ++++++---
 gdb/nat/linux-ptrace.c       |  85 ++++++++------------
 gdb/nat/linux-ptrace.h       |   1 -
 gdb/remote.c                 | 130 +++++++++++++++++++++++++------
 14 files changed, 415 insertions(+), 106 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index be75baf..c9c2e62 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,35 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* linux-nat.c (linux_nat_ptrace_options): New function.
+	(linux_init_ptrace, wait_lwp, linux_nat_filter_event):
+	Call linux_nat_ptrace_options and use different argument to
+	linux_enable_event_reporting.
+	(_initialize_linux_nat): Delete call to
+	linux_ptrace_set_additional_flags.
+	* nat/linux-ptrace.c (current_ptrace_options): Rename to 
+	supported_ptrace_options.
+	(additional_flags): Delete variable.
+	(linux_check_ptrace_features): Use supported_ptrace_options.
+	(linux_test_for_tracesysgood, linux_test_for_tracefork):
+	Likewise, and remove additional_flags check.
+	(linux_enable_event_reporting): Change 'attached' argument to
+	'options'.  Use supported_ptrace_options.
+	(ptrace_supports_feature): Change comment.  Use 
+	supported_ptrace_options.
+	(linux_ptrace_set_additional_flags): Delete function.
+	* nat/linux-ptrace.h (linux_ptrace_set_additional_flags):
+	Delete function prototype.
+	* remote.c (remote_fork_event_p): New function.
+	(remote_detach_pid): New function.
+	(remote_detach_1): Call remote_detach_pid, don't mourn inferior
+	if doing detach-on-fork.
+	(remote_follow_fork): New function.
+	(remote_parse_stop_reply): Handle new "T" stop reason "fork".
+	(remote_pid_to_str): Print "process" strings for pid/0/0 ptids.
+	(init_extended_remote_ops): Initialize to_follow_fork.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* nat/linux-ptrace.c (linux_check_ptrace_features): Change
 	from static to extern.
 	* nat/linux-ptrace.h (linux_check_ptrace_features): Declare.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 73788ec..0ef695c 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,32 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* linux-low.c (handle_extended_wait): Implement return value,
+	rename argument 'event_child' to 'event_lwp', handle
+	PTRACE_EVENT_FORK, call internal_error for unrecognized event.
+	(linux_low_ptrace_options): New function.
+	(linux_low_filter_event): Call linux_low_ptrace_options,
+	use different argument fo linux_enable_event_reporting,
+	use return value from handle_extended_wait.
+	(extended_event_reported): New function.
+	(linux_wait_1): Call extended_event_reported and set
+	status to report fork events.
+	(linux_write_memory): Add pid to debug message.
+	(reset_lwp_ptrace_options_callback): New function.
+	(linux_handle_new_gdb_connection): New function.
+	(linux_target_ops): Initialize new structure member.
+	* linux-low.h (struct lwp_info) <waitstatus>: New member.
+	* lynx-low.c: Initialize new structure member.
+	* remote-utils.c (prepare_resume_reply): Implement stop reason
+	"fork" for "T" stop message.
+	* server.c (handle_query): Call handle_new_gdb_connection.
+	* server.h (report_fork_events): Declare global flag.
+	* target.h (struct target_ops) <handle_new_gdb_connection>:
+	New member.
+	(target_handle_new_gdb_connection): New macro.
+	* win32-low.c: Initialize new structure member.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* mem-break.c (APPEND_TO_LIST): Define macro.
 	(clone_agent_expr): New function.
 	(clone_one_breakpoint): New function.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 1724b54..b280c17 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -20,6 +20,7 @@
 #include "linux-low.h"
 #include "nat/linux-osdata.h"
 #include "agent.h"
+#include "tdesc.h"
 
 #include "nat/linux-nat.h"
 #include "nat/linux-waitpid.h"
@@ -414,22 +415,23 @@ linux_add_process (int pid, int attached)
 static CORE_ADDR get_pc (struct lwp_info *lwp);
 
 /* Handle a GNU/Linux extended wait response.  If we see a clone
-   event, we need to add the new LWP to our list (and not report the
-   trap to higher layers).  */
+   event, we need to add the new LWP to our list (and return 0 so as
+   not to report the trap to higher layers).  */
 
-static void
-handle_extended_wait (struct lwp_info *event_child, int wstat)
+static int
+handle_extended_wait (struct lwp_info *event_lwp, int wstat)
 {
   int event = linux_ptrace_get_extended_event (wstat);
-  struct thread_info *event_thr = get_lwp_thread (event_child);
+  struct thread_info *event_thr = get_lwp_thread (event_lwp);
   struct lwp_info *new_lwp;
 
-  if (event == PTRACE_EVENT_CLONE)
+  if ((event == PTRACE_EVENT_FORK) || (event == PTRACE_EVENT_CLONE))
     {
       ptid_t ptid;
       unsigned long new_pid;
       int ret, status;
 
+      /* Get the pid of the new lwp.  */
       ptrace (PTRACE_GETEVENTMSG, lwpid_of (event_thr), (PTRACE_TYPE_ARG3) 0,
 	      &new_pid);
 
@@ -449,6 +451,57 @@ handle_extended_wait (struct lwp_info *event_child, int wstat)
 	    warning ("wait returned unexpected status 0x%x", status);
 	}
 
+      if (event == PTRACE_EVENT_FORK)
+	{
+	  struct process_info *parent_proc;
+	  struct process_info *child_proc;
+	  struct lwp_info *child_lwp;
+	  struct target_desc *tdesc;
+
+	  ptid = ptid_build (new_pid, new_pid, 0);
+
+	  if (debug_threads)
+	    {
+	      debug_printf ("HEW: Got fork event from LWP %ld, "
+			    "new child is %d\n",
+			    ptid_get_lwp (ptid_of (event_thr)),
+			    ptid_get_pid (ptid));
+	    }
+
+	  /* Add the new process to the tables and clone the breakpoint
+	     lists of the parent.  We need to do this even if the new process
+	     will be detached, since we will need the process object and the
+	     breakpoints to remove any breakpoints from memory when we
+	     detach, and the client side will access registers.  */
+	  child_proc = linux_add_process (new_pid, 0);
+	  gdb_assert (child_proc != NULL);
+	  child_lwp = add_lwp (ptid);
+	  gdb_assert (child_lwp != NULL);
+	  child_lwp->stopped = 1;
+	  parent_proc = get_thread_process (event_thr);
+	  child_proc->attached = parent_proc->attached;
+	  clone_all_breakpoints (&child_proc->breakpoints,
+				 &child_proc->raw_breakpoints,
+				 parent_proc->breakpoints);
+
+	  tdesc = xmalloc (sizeof (struct target_desc));
+	  copy_target_description (tdesc, parent_proc->tdesc);
+	  child_proc->tdesc = tdesc;
+	  child_lwp->must_set_ptrace_flags = 1;
+
+	  /* Save fork info in the parent thread.  */
+	  event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED;
+	  event_lwp->waitstatus.value.related_pid = ptid;
+	  /* The status_pending field contains bits denoting the
+	     extended event, so when the pending event is handled,
+	     the handler will look at lwp->waitstatus.  */
+	  event_lwp->status_pending_p = 1;
+	  event_lwp->status_pending = wstat;
+
+	  /* Report the event.  */
+	  return 0;
+	}
+
       if (debug_threads)
 	debug_printf ("HEW: Got clone event "
 		      "from LWP %ld, new child is LWP %ld\n",
@@ -477,7 +530,12 @@ handle_extended_wait (struct lwp_info *event_child, int wstat)
 	  new_lwp->status_pending_p = 1;
 	  new_lwp->status_pending = status;
 	}
+
+      /* Don't report the event.  */
+      return 1;
     }
+
+  internal_error (__FILE__, __LINE__, _("unknown ptrace event %d"), event);
 }
 
 /* Return the PC as read from the regcache of LWP, without any
@@ -1935,6 +1993,22 @@ check_stopped_by_watchpoint (struct lwp_info *child)
   return child->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
 }
 
+/* Return the ptrace options that we want to try to enable.  */
+
+static int
+linux_low_ptrace_options (int attached)
+{
+  int options = 0;
+
+  if (!attached)
+    options |= PTRACE_O_EXITKILL;
+
+  if (report_fork_events)
+    options |= PTRACE_O_TRACEFORK;
+
+  return options;
+}
+
 /* Do low-level handling of the event, and check if we should go on
    and pass it to caller code.  Return the affected lwp if we are, or
    NULL otherwise.  */
@@ -2022,8 +2096,9 @@ linux_low_filter_event (int lwpid, int wstat)
   if (WIFSTOPPED (wstat) && child->must_set_ptrace_flags)
     {
       struct process_info *proc = find_process_pid (pid_of (thread));
+      int options = linux_low_ptrace_options (proc->attached);
 
-      linux_enable_event_reporting (lwpid, proc->attached);
+      linux_enable_event_reporting (lwpid, options);
       child->must_set_ptrace_flags = 0;
     }
 
@@ -2033,8 +2108,12 @@ linux_low_filter_event (int lwpid, int wstat)
       && linux_is_extended_waitstatus (wstat))
     {
       child->stop_pc = get_pc (child);
-      handle_extended_wait (child, wstat);
-      return NULL;
+      if (handle_extended_wait (child, wstat))
+	{
+	  /* The event has been handled, so just return without
+	     reporting it.  */
+	  return NULL;
+	}
     }
 
   /* Check first whether this was a SW/HW breakpoint before checking
@@ -2622,6 +2701,18 @@ ignore_event (struct target_waitstatus *ourstatus)
   return null_ptid;
 }
 
+/* Return non-zero if WAITSTATUS reflects an extended linux
+   event.  Otherwise, return zero.  */
+
+static int
+extended_event_reported (const struct target_waitstatus *waitstatus)
+{
+  if (waitstatus == NULL)
+    return 0;
+
+  return (waitstatus->kind == TARGET_WAITKIND_FORKED);
+}
+
 /* Wait for process, returns status.  */
 
 static ptid_t
@@ -2988,7 +3079,8 @@ linux_wait_1 (ptid_t ptid,
 		       && !bp_explains_trap && !trace_event)
 		   || (gdb_breakpoint_here (event_child->stop_pc)
 		       && gdb_condition_true_at_breakpoint (event_child->stop_pc)
-		       && gdb_no_commands_at_breakpoint (event_child->stop_pc)));
+		       && gdb_no_commands_at_breakpoint (event_child->stop_pc))
+		   || extended_event_reported (&event_child->waitstatus));
 
   run_breakpoint_commands (event_child->stop_pc);
 
@@ -3010,6 +3102,13 @@ linux_wait_1 (ptid_t ptid,
 			  paddress (event_child->stop_pc),
 			  paddress (event_child->step_range_start),
 			  paddress (event_child->step_range_end));
+	  if (extended_event_reported (&event_child->waitstatus))
+	    {
+	      char *str = target_waitstatus_to_string (ourstatus);
+	      debug_printf ("LWP %ld: extended event with waitstatus %s\n",
+			    lwpid_of (get_lwp_thread (event_child)), str);
+	      xfree (str);
+	    }
 	}
 
       /* We're not reporting this breakpoint to GDB, so apply the
@@ -3119,7 +3218,17 @@ linux_wait_1 (ptid_t ptid,
 	unstop_all_lwps (1, event_child);
     }
 
-  ourstatus->kind = TARGET_WAITKIND_STOPPED;
+  if (extended_event_reported (&event_child->waitstatus))
+    {
+      /* If the reported event is a fork, vfork or exec, let GDB know.  */
+      ourstatus->kind = event_child->waitstatus.kind;
+      ourstatus->value = event_child->waitstatus.value;
+
+      /* Clear the event lwp's waitstatus since we handled it already.  */
+      event_child->waitstatus.kind = TARGET_WAITKIND_IGNORE;
+    }
+  else
+    ourstatus->kind = TARGET_WAITKIND_STOPPED;
 
   /* Now that we've selected our final event LWP, un-adjust its PC if
      it was a software breakpoint, and the client doesn't know we can
@@ -3152,7 +3261,7 @@ linux_wait_1 (ptid_t ptid,
 	 but, it stopped for other reasons.  */
       ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (w));
     }
-  else
+  else if (ourstatus->kind == TARGET_WAITKIND_STOPPED)
     {
       ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (w));
     }
@@ -4996,8 +5105,8 @@ linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
 	val = val & 0xffff;
       else if (len == 3)
 	val = val & 0xffffff;
-      debug_printf ("Writing %0*x to 0x%08lx\n", 2 * ((len < 4) ? len : 4),
-		    val, (long)memaddr);
+      debug_printf ("Writing %0*x to 0x%08lx in process %d\n",
+		    2 * ((len < 4) ? len : 4), val, (long)memaddr, pid);
     }
 
   /* Fill start and end extra bytes of buffer with existing memory data.  */
@@ -5454,6 +5563,48 @@ linux_supports_vfork_events (void)
   return linux_supports_tracefork ();
 }
 
+/* Callback for 'find_inferior'.  Set the (possibly changed) ptrace
+   options for the specified lwp.  */
+
+static int
+reset_lwp_ptrace_options_callback (struct inferior_list_entry *entry,
+				   void *args)
+{
+  struct thread_info *thread = (struct thread_info *) entry;
+  struct lwp_info *lwp = get_thread_lwp (thread);
+
+  if (!lwp->stopped)
+    {
+      /* Stop the lwp so we can modify its ptrace options.  */
+      lwp->must_set_ptrace_flags = 1;
+      linux_stop_lwp (lwp);
+    }
+  else
+    {
+      /* Already stopped; go ahead and set the ptrace options.  */
+      struct process_info *proc = find_process_pid (pid_of (thread));
+      int options = linux_low_ptrace_options (proc->attached);
+
+      linux_enable_event_reporting (lwpid_of (thread), options);
+      lwp->must_set_ptrace_flags = 0;
+    }
+
+  return 0;
+}
+
+/* Target hook for 'handle_new_gdb_connection'.  Causes a reset of the
+   ptrace flags for all inferiors.  This is in case the new GDB connection
+   doesn't support the same set of events that the previous one did.  */
+
+static void
+linux_handle_new_gdb_connection (void)
+{
+  pid_t pid;
+
+  /* Request that all the lwps reset their ptrace options.  */
+  find_inferior (&all_threads, reset_lwp_ptrace_options_callback , &pid);
+}
+
 static int
 linux_supports_disable_randomization (void)
 {
@@ -6429,6 +6580,7 @@ static struct target_ops linux_target_ops = {
   linux_supports_multi_process,
   linux_supports_fork_events,
   linux_supports_vfork_events,
+  linux_handle_new_gdb_connection,
 #ifdef USE_THREAD_DB
   thread_db_handle_monitor_command,
 #else
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index 1ae3701..41067d6 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -271,6 +271,10 @@ struct lwp_info
   /* When stopped is set, the last wait status recorded for this lwp.  */
   int last_status;
 
+  /* This is used to store extended ptrace event information until
+     it is reported to GDB.  */
+  struct target_waitstatus waitstatus;
+
   /* When stopped is set, this is where the lwp last stopped, with
      decr_pc_after_break already accounted for.  If the LWP is
      running, this is the address at which the lwp was resumed.  */
diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c
index f087416..ee7b28a 100644
--- a/gdb/gdbserver/lynx-low.c
+++ b/gdb/gdbserver/lynx-low.c
@@ -764,6 +764,7 @@ static struct target_ops lynx_target_ops = {
   NULL,  /* supports_multi_process */
   NULL,  /* supports_fork_events */
   NULL,  /* supports_vfork_events */
+  NULL,  /* handle_new_gdb_connection */
   NULL,  /* handle_monitor_command */
 };
 
diff --git a/gdb/gdbserver/remote-utils.c b/gdb/gdbserver/remote-utils.c
index 1de86be..6078348 100644
--- a/gdb/gdbserver/remote-utils.c
+++ b/gdb/gdbserver/remote-utils.c
@@ -1114,12 +1114,24 @@ prepare_resume_reply (char *buf, ptid_t ptid,
   switch (status->kind)
     {
     case TARGET_WAITKIND_STOPPED:
+    case TARGET_WAITKIND_FORKED:
       {
 	struct thread_info *saved_thread;
 	const char **regp;
 	struct regcache *regcache;
 
-	sprintf (buf, "T%02x", status->value.sig);
+	if (status->kind == TARGET_WAITKIND_FORKED && report_fork_events)
+	  {
+	    enum gdb_signal signal = GDB_SIGNAL_TRAP;
+
+	    sprintf (buf, "T%02xfork:", signal);
+	    buf += strlen (buf);
+	    buf = write_ptid (buf, status->value.related_pid);
+	    strcat (buf, ";");
+	  }
+	else
+	  sprintf (buf, "T%02x", status->value.sig);
+
 	buf += strlen (buf);
 
 	saved_thread = current_thread;
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 1544e99..3969267 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -2160,6 +2160,9 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       if (the_target->pid_to_exec_file != NULL)
 	strcat (own_buf, ";qXfer:exec-file:read+");
 
+      /* Reinitialize the target as needed for the new connection.  */
+      target_handle_new_gdb_connection ();
+
       return;
     }
 
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 91d4080..696a24e 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -84,6 +84,7 @@ extern int disable_packet_qfThreadInfo;
 
 extern int run_once;
 extern int multi_process;
+extern int report_fork_events;
 extern int non_stop;
 
 /* True if the "swbreak+" feature is active.  In that case, GDB wants
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index 697b223..8d23383 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -287,6 +287,9 @@ struct target_ops
   /* Returns true if vfork events are supported.  */
   int (*supports_vfork_events) (void);
 
+  /* Allows target to re-initialize connection-specific settings.  */
+  void (*handle_new_gdb_connection) (void);
+
   /* If not NULL, target-specific routine to process monitor command.
      Returns 1 if handled, or 0 to perform default processing.  */
   int (*handle_monitor_command) (char *);
@@ -434,6 +437,10 @@ int kill_inferior (int);
   (the_target->supports_vfork_events ? \
    (*the_target->supports_vfork_events) () : 0)
 
+#define target_handle_new_gdb_connection() \
+  (the_target->handle_new_gdb_connection ? \
+   (*the_target->handle_new_gdb_connection) () : 0)
+
 #define detach_inferior(pid) \
   (*the_target->detach) (pid)
 
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index a58f963..699115c 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -1833,6 +1833,7 @@ static struct target_ops win32_target_ops = {
   NULL, /* supports_multi_process */
   NULL, /* supports_fork_events */
   NULL, /* supports_vfork_events */
+  NULL, /* handle_new_gdb_connection */
   NULL, /* handle_monitor_command */
   NULL, /* core_of_thread */
   NULL, /* read_loadmap */
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index b04aa68..f95e76c 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -368,6 +368,25 @@ pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
   return 0;
 }
 
+/* Return the ptrace options that we want to try to enable.  */
+
+static int
+linux_nat_ptrace_options (int attached)
+{
+  int options = 0;
+
+  if (!attached)
+    options |= PTRACE_O_EXITKILL;
+
+  options |= (PTRACE_O_TRACESYSGOOD
+	      | PTRACE_O_TRACEVFORKDONE
+	      | PTRACE_O_TRACEVFORK
+	      | PTRACE_O_TRACEFORK
+	      | PTRACE_O_TRACEEXEC);
+
+  return options;
+}
+
 /* Initialize ptrace warnings and check for supported ptrace
    features given PID.
 
@@ -376,7 +395,9 @@ pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
 static void
 linux_init_ptrace (pid_t pid, int attached)
 {
-  linux_enable_event_reporting (pid, attached);
+  int options = linux_nat_ptrace_options (attached);
+
+  linux_enable_event_reporting (pid, options);
   linux_ptrace_init_warnings ();
 }
 
@@ -2301,8 +2322,9 @@ wait_lwp (struct lwp_info *lp)
   if (lp->must_set_ptrace_flags)
     {
       struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
+      int options = linux_nat_ptrace_options (inf->attach_flag);
 
-      linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
+      linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
       lp->must_set_ptrace_flags = 0;
     }
 
@@ -3102,8 +3124,9 @@ linux_nat_filter_event (int lwpid, int status)
   if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
     {
       struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
+      int options = linux_nat_ptrace_options (inf->attach_flag);
 
-      linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
+      linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
       lp->must_set_ptrace_flags = 0;
     }
 
@@ -5028,14 +5051,6 @@ Enables printf debugging output."),
   sigdelset (&suspend_mask, SIGCHLD);
 
   sigemptyset (&blocked_mask);
-
-  /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
-     support read-only process state.  */
-  linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
-				     | PTRACE_O_TRACEVFORKDONE
-				     | PTRACE_O_TRACEVFORK
-				     | PTRACE_O_TRACEFORK
-				     | PTRACE_O_TRACEEXEC);
 }
 \f
 
diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
index aba3da8..fb12606 100644
--- a/gdb/nat/linux-ptrace.c
+++ b/gdb/nat/linux-ptrace.c
@@ -25,14 +25,10 @@
 
 #include <stdint.h>
 
-/* Stores the currently supported ptrace options.  A value of
-   -1 means we did not check for features yet.  A value of 0 means
-   there are no supported features.  */
-static int current_ptrace_options = -1;
-
-/* Additional flags to test.  */
-
-static int additional_flags;
+/* Stores the ptrace options supported by the running kernel.
+   A value of -1 means we did not check for features yet.  A value
+   of 0 means there are no supported features.  */
+static int supported_ptrace_options = -1;
 
 /* Find all possible reasons we could fail to attach PID and append
    these as strings to the already initialized BUFFER.  '\0'
@@ -343,7 +339,7 @@ linux_check_ptrace_features (void)
   int child_pid, ret, status;
 
   /* Initialize the options.  */
-  current_ptrace_options = 0;
+  supported_ptrace_options = 0;
 
   /* Fork a child so we can do some testing.  The child will call
      linux_child_function and will get traced.  The child will
@@ -387,14 +383,11 @@ linux_test_for_tracesysgood (int child_pid)
 {
   int ret;
 
-  if ((additional_flags & PTRACE_O_TRACESYSGOOD) == 0)
-    return;
-
   ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
 		(PTRACE_TYPE_ARG4) PTRACE_O_TRACESYSGOOD);
 
   if (ret == 0)
-    current_ptrace_options |= PTRACE_O_TRACESYSGOOD;
+    supported_ptrace_options |= PTRACE_O_TRACESYSGOOD;
 }
 
 /* Determine if PTRACE_O_TRACEFORK can be used to follow fork
@@ -414,15 +407,12 @@ linux_test_for_tracefork (int child_pid)
   if (ret != 0)
     return;
 
-  if ((additional_flags & PTRACE_O_TRACEVFORKDONE) != 0)
-    {
-      /* Check if the target supports PTRACE_O_TRACEVFORKDONE.  */
-      ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
-		    (PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK
-					| PTRACE_O_TRACEVFORKDONE));
-      if (ret == 0)
-	current_ptrace_options |= PTRACE_O_TRACEVFORKDONE;
-    }
+  /* Check if the target supports PTRACE_O_TRACEVFORKDONE.  */
+  ret = ptrace (PTRACE_SETOPTIONS, child_pid, (PTRACE_TYPE_ARG3) 0,
+		(PTRACE_TYPE_ARG4) (PTRACE_O_TRACEFORK
+				    | PTRACE_O_TRACEVFORKDONE));
+  if (ret == 0)
+    supported_ptrace_options |= PTRACE_O_TRACEVFORKDONE;
 
   /* Setting PTRACE_O_TRACEFORK did not cause an error, however we
      don't know for sure that the feature is available; old
@@ -458,10 +448,10 @@ linux_test_for_tracefork (int child_pid)
 
 	  /* We got the PID from the grandchild, which means fork
 	     tracing is supported.  */
-	  current_ptrace_options |= PTRACE_O_TRACECLONE;
-	  current_ptrace_options |= (additional_flags & (PTRACE_O_TRACEFORK
-                                                         | PTRACE_O_TRACEVFORK
-                                                         | PTRACE_O_TRACEEXEC));
+	  supported_ptrace_options |= PTRACE_O_TRACECLONE;
+	  supported_ptrace_options |= (PTRACE_O_TRACEFORK
+				       | PTRACE_O_TRACEVFORK
+				       | PTRACE_O_TRACEEXEC);
 
 	  /* Do some cleanup and kill the grandchild.  */
 	  my_waitpid (second_pid, &second_status, 0);
@@ -489,33 +479,31 @@ linux_test_for_exitkill (int child_pid)
 		(PTRACE_TYPE_ARG4) PTRACE_O_EXITKILL);
 
   if (ret == 0)
-    current_ptrace_options |= PTRACE_O_EXITKILL;
+    supported_ptrace_options |= PTRACE_O_EXITKILL;
 }
 
 /* Enable reporting of all currently supported ptrace events.
-   ATTACHED should be nonzero if we have attached to the inferior.  */
+   OPTIONS is a bit mask of extended features we want enabled,
+   if supported by the kernel.  PTRACE_O_TRACECLONE is always
+   enabled, if supported.  */
 
 void
-linux_enable_event_reporting (pid_t pid, int attached)
+linux_enable_event_reporting (pid_t pid, int options)
 {
-  int ptrace_options;
-
   /* Check if we have initialized the ptrace features for this
      target.  If not, do it now.  */
-  if (current_ptrace_options == -1)
+  if (supported_ptrace_options == -1)
     linux_check_ptrace_features ();
 
-  ptrace_options = current_ptrace_options;
-  if (attached)
-    {
-      /* When attached to our inferior, we do not want the inferior
-	 to die with us if we terminate unexpectedly.  */
-      ptrace_options &= ~PTRACE_O_EXITKILL;
-    }
+  /* We always want clone events.  */
+  options |= PTRACE_O_TRACECLONE;
+
+  /* Filter out unsupported options.  */
+  options &= supported_ptrace_options;
 
   /* Set the options.  */
   ptrace (PTRACE_SETOPTIONS, pid, (PTRACE_TYPE_ARG3) 0,
-	  (PTRACE_TYPE_ARG4) (uintptr_t) ptrace_options);
+	  (PTRACE_TYPE_ARG4) (uintptr_t) options);
 }
 
 /* Disable reporting of all currently supported ptrace events.  */
@@ -528,16 +516,16 @@ linux_disable_event_reporting (pid_t pid)
 }
 
 /* Returns non-zero if PTRACE_OPTIONS is contained within
-   CURRENT_PTRACE_OPTIONS, therefore supported.  Returns 0
+   SUPPORTED_PTRACE_OPTIONS, therefore supported.  Returns 0
    otherwise.  */
 
 static int
 ptrace_supports_feature (int ptrace_options)
 {
-  if (current_ptrace_options == -1)
+  if (supported_ptrace_options == -1)
     linux_check_ptrace_features ();
 
-  return ((current_ptrace_options & ptrace_options) == ptrace_options);
+  return ((supported_ptrace_options & ptrace_options) == ptrace_options);
 }
 
 /* Returns non-zero if PTRACE_EVENT_FORK is supported by ptrace,
@@ -595,17 +583,6 @@ linux_ptrace_init_warnings (void)
   linux_ptrace_test_ret_to_nx ();
 }
 
-/* Set additional ptrace flags to use.  Some such flags may be checked
-   by the implementation above.  This function must be called before
-   any other function in this file; otherwise the flags may not take
-   effect appropriately.  */
-
-void
-linux_ptrace_set_additional_flags (int flags)
-{
-  additional_flags = flags;
-}
-
 /* Extract extended ptrace event from wait status.  */
 
 int
diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h
index 03d98c9..1db0cde 100644
--- a/gdb/nat/linux-ptrace.h
+++ b/gdb/nat/linux-ptrace.h
@@ -156,7 +156,6 @@ extern int linux_supports_tracefork (void);
 extern int linux_supports_traceclone (void);
 extern int linux_supports_tracevforkdone (void);
 extern int linux_supports_tracesysgood (void);
-extern void linux_ptrace_set_additional_flags (int);
 extern int linux_ptrace_get_extended_event (int wstat);
 extern int linux_is_extended_waitstatus (int wstat);
 extern int linux_wstatus_maybe_breakpoint (int wstat);
diff --git a/gdb/remote.c b/gdb/remote.c
index 6dae920..390d30d 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -1462,6 +1462,14 @@ remote_multi_process_p (struct remote_state *rs)
   return packet_support (PACKET_multiprocess_feature) == PACKET_ENABLE;
 }
 
+/* Returns true if fork events are supported.  */
+
+static int
+remote_fork_event_p (struct remote_state *rs)
+{
+  return packet_support (PACKET_fork_event_feature) == PACKET_ENABLE;
+}
+
 /* Tokens for use by the asynchronous signal handlers for SIGINT.  */
 static struct async_signal_handler *async_sigint_remote_twice_token;
 static struct async_signal_handler *async_sigint_remote_token;
@@ -4430,16 +4438,42 @@ remote_open_1 (const char *name, int from_tty,
     wait_forever_enabled_p = 1;
 }
 
-/* This takes a program previously attached to and detaches it.  After
-   this is done, GDB can be used to debug some other program.  We
-   better not have left any breakpoints in the target program or it'll
-   die when it hits one.  */
+/* Detach the specified process.  */
+
+static void
+remote_detach_pid (int pid)
+{
+  struct remote_state *rs = get_remote_state ();
+
+  if (remote_multi_process_p (rs))
+    xsnprintf (rs->buf, get_remote_packet_size (), "D;%x", pid);
+  else
+    strcpy (rs->buf, "D");
+
+  putpkt (rs->buf);
+  getpkt (&rs->buf, &rs->buf_size, 0);
+
+  if (rs->buf[0] == 'O' && rs->buf[1] == 'K')
+    ;
+  else if (rs->buf[0] == '\0')
+    error (_("Remote doesn't know how to detach"));
+  else
+    error (_("Can't detach process."));
+}
+
+/* This detaches a program to which we previously attached, using
+   inferior_ptid to identify the process.  After this is done, GDB
+   can be used to debug some other program.  We better not have left
+   any breakpoints in the target program or it'll die when it hits
+   one.  */
 
 static void
-remote_detach_1 (const char *args, int from_tty, int extended)
+remote_detach_1 (const char *args, int from_tty)
 {
   int pid = ptid_get_pid (inferior_ptid);
   struct remote_state *rs = get_remote_state ();
+  struct thread_info *tp = find_thread_ptid (inferior_ptid);
+  int is_fork_parent;
 
   if (args)
     error (_("Argument given to \"detach\" when remotely debugging."));
@@ -4458,37 +4492,74 @@ remote_detach_1 (const char *args, int from_tty, int extended)
     }
 
   /* Tell the remote target to detach.  */
-  if (remote_multi_process_p (rs))
-    xsnprintf (rs->buf, get_remote_packet_size (), "D;%x", pid);
-  else
-    strcpy (rs->buf, "D");
+  remote_detach_pid (pid);
 
-  putpkt (rs->buf);
-  getpkt (&rs->buf, &rs->buf_size, 0);
-
-  if (rs->buf[0] == 'O' && rs->buf[1] == 'K')
-    ;
-  else if (rs->buf[0] == '\0')
-    error (_("Remote doesn't know how to detach"));
-  else
-    error (_("Can't detach process."));
-
-  if (from_tty && !extended)
+  if (from_tty && !rs->extended)
     puts_filtered (_("Ending remote debugging.\n"));
 
-  target_mourn_inferior ();
+  /* Check to see if we are detaching a fork parent.  Note that if we
+     are detaching a fork child, tp == NULL.  */
+  is_fork_parent = (tp != NULL
+		    && tp->pending_follow.kind == TARGET_WAITKIND_FORKED);
+
+  /* If doing detach-on-fork, we don't mourn, because that will delete
+     breakpoints that should be available for the followed inferior.  */
+  if (!is_fork_parent)
+    target_mourn_inferior ();
+  else
+    {
+      inferior_ptid = null_ptid;
+      detach_inferior (pid);
+    }
 }
 
 static void
 remote_detach (struct target_ops *ops, const char *args, int from_tty)
 {
-  remote_detach_1 (args, from_tty, 0);
+  remote_detach_1 (args, from_tty);
 }
 
 static void
 extended_remote_detach (struct target_ops *ops, const char *args, int from_tty)
 {
-  remote_detach_1 (args, from_tty, 1);
+  remote_detach_1 (args, from_tty);
+}
+
+/* Target follow-fork function for remote targets.  On entry, and
+   at return, the current inferior is the fork parent.
+
+   Note that although this is currently only used for extended-remote,
+   it is named remote_follow_fork in anticipation of using it for the
+   remote target as well.  */
+
+static int
+remote_follow_fork (struct target_ops *ops, int follow_child,
+		    int detach_fork)
+{
+  struct remote_state *rs = get_remote_state ();
+
+  if (remote_fork_event_p (rs))
+    {
+      /* When following the parent and detaching the child, we detach
+	 the child here.  For the case of following the child and
+	 detaching the parent, the detach is done in the target-
+	 independent follow fork code in infrun.c.  We can't use
+	 target_detach when detaching an unfollowed child because
+	 the client side doesn't know anything about the child.  */
+      if (detach_fork && !follow_child)
+	{
+	  /* Detach the fork child.  */
+	  ptid_t child_ptid;
+	  pid_t child_pid;
+
+	  child_ptid = inferior_thread ()->pending_follow.value.related_pid;
+	  child_pid = ptid_get_pid (child_ptid);
+
+	  remote_detach_pid (child_pid);
+	  detach_inferior (child_pid);
+	}
+    }
+  return 0;
 }
 
 /* Same as remote_detach, but don't send the "D" packet; just disconnect.  */
@@ -5651,6 +5722,11 @@ Packet: '%s'\n"),
 	      p = unpack_varlen_hex (++p1, &c);
 	      event->core = c;
 	    }
+	  else if (strncmp (p, "fork", p1 - p) == 0)
+	    {
+	      event->ws.value.related_pid = read_ptid (++p1, &p);
+	      event->ws.kind = TARGET_WAITKIND_FORKED;
+	    }
 	  else
 	    {
 	      ULONGEST pnum;
@@ -9505,8 +9581,11 @@ remote_pid_to_str (struct target_ops *ops, ptid_t ptid)
       if (ptid_equal (magic_null_ptid, ptid))
 	xsnprintf (buf, sizeof buf, "Thread <main>");
       else if (rs->extended && remote_multi_process_p (rs))
-	xsnprintf (buf, sizeof buf, "Thread %d.%ld",
-		   ptid_get_pid (ptid), ptid_get_lwp (ptid));
+	if (ptid_get_lwp (ptid) == 0)
+	  return normal_pid_to_str (ptid);
+	else
+	  xsnprintf (buf, sizeof buf, "Thread %d.%ld",
+		     ptid_get_pid (ptid), ptid_get_lwp (ptid));
       else
 	xsnprintf (buf, sizeof buf, "Thread %ld",
 		   ptid_get_lwp (ptid));
@@ -11870,6 +11949,7 @@ Specify the serial device it is connected to (e.g. /dev/ttya).";
   extended_remote_ops.to_kill = extended_remote_kill;
   extended_remote_ops.to_supports_disable_randomization
     = extended_remote_supports_disable_randomization;
+  extended_remote_ops.to_follow_fork = remote_follow_fork;
 }
 
 static int
-- 
1.8.1.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [pushed][PATCH 1/7] Identify remote fork event support
@ 2015-05-12 17:28 Don Breazeal
  2015-05-12 17:28 ` [pushed][PATCH 3/7] Extended-remote Linux follow fork Don Breazeal
                   ` (5 more replies)
  0 siblings, 6 replies; 13+ messages in thread
From: Don Breazeal @ 2015-05-12 17:28 UTC (permalink / raw)
  To: gdb-patches

This is the version of the patch that I pushed.
Thanks
--Don


This patch implements a mechanism for GDB to determine whether fork
events are supported in gdbserver.  This is a preparatory patch for
remote fork and exec event support.

Two new RSP packets are defined to represent fork and vfork event
support.  These packets are used just like PACKET_multiprocess_feature
to denote whether the corresponding event is supported.  GDB sends
fork-events+ and vfork-events+ to gdbserver to inquire about fork
event support.  If the response enables these packets, then GDB
knows that gdbserver supports the corresponding events and will
enable them.

Target functions used to query for support are included along with
each new packet.

In order for gdbserver to know whether the events are supported at the
point where the qSupported packet arrives, the code in nat/linux-ptrace.c
had to be reorganized.  Previously it would test for fork/exec event
support, then enable the events using the pid of the inferior.  When the
qSupported packet arrives there may not be an inferior.  So the mechanism
was split into two parts: a function that checks whether the events are
supported, called when gdbserver starts up, and another that enables the
events when the inferior stops for the first time.

Another gdbserver change was to add some global variables similar to
multi_process, one per new packet.  These are used to control whether
the corresponding fork events are enabled.  If GDB does not inquire
about the event support in the qSupported packet, then gdbserver will
not set these "report the event" flags.  If the flags are not set, the
events are ignored like they were in the past.  Thus, gdbserver will
never send fork event notification to an older GDB that doesn't
recognize fork events.

Tested on Ubuntu x64, native/remote/extended-remote, and as part of
subsequent patches in the series.

gdb/gdbserver/ChangeLog:

        * linux-low.c (linux_supports_fork_events): New function.
        (linux_supports_vfork_events): New function.
        (linux_target_ops): Initialize new structure members.
        (initialize_low): Call linux_check_ptrace_features.
        * lynx-low.c (lynx_target_ops): Initialize new structure
        members.
        * server.c (report_fork_events, report_vfork_events):
        New global flags.
        (handle_query): Add new features to qSupported packet and
        response.
        (captured_main): Initialize new global variables.
        * target.h (struct target_ops) <supports_fork_events>:
        New member.
        <supports_vfork_events>: New member.
        (target_supports_fork_events): New macro.
        (target_supports_vfork_events): New macro.
        * win32-low.c (win32_target_ops): Initialize new structure
        members.

gdb/ChangeLog:

        * nat/linux-ptrace.c (linux_check_ptrace_features): Change
        from static to extern.
        * nat/linux-ptrace.h (linux_check_ptrace_features): Declare.
        * remote.c (anonymous enum): <PACKET_fork_event_feature,
        * PACKET_vfork_event_feature>: New enumeration constants.
        (remote_protocol_features): Add table entries for new packets.
        (remote_query_supported): Add new feature queries to qSupported
        packet.
        (_initialize_remote): Exempt new packets from the requirement
        to have 'set remote' commands.
---
 gdb/ChangeLog             | 11 +++++++++++
 gdb/gdbserver/ChangeLog   | 21 +++++++++++++++++++++
 gdb/gdbserver/linux-low.c | 20 ++++++++++++++++++++
 gdb/gdbserver/lynx-low.c  |  2 ++
 gdb/gdbserver/server.c    | 22 ++++++++++++++++++++++
 gdb/gdbserver/target.h    | 14 ++++++++++++++
 gdb/gdbserver/win32-low.c |  2 ++
 gdb/nat/linux-ptrace.c    |  2 +-
 gdb/nat/linux-ptrace.h    |  1 +
 gdb/remote.c              | 26 ++++++++++++++++++++++++++
 10 files changed, 120 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7f4b457..be75baf 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,14 @@
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
+	* nat/linux-ptrace.c (linux_check_ptrace_features): Change
+	from static to extern.
+	* nat/linux-ptrace.h (linux_check_ptrace_features): Declare.
+	* remote.c (anonymous enum): <PACKET_fork_event_feature,
+	* PACKET_vfork_event_feature>: New enumeration constants.
+	(remote_protocol_features): Add table entries for new packets.
+	(remote_query_supported): Add new feature queries to qSupported
+	packet.
+
 2015-05-12  Gary Benson <gbenson@redhat.com>
 
 	* remote.c (remote_add_inferior): Call exec_file_locate_attach
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 94146b8..a37051d 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,24 @@
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
+	* linux-low.c (linux_supports_fork_events): New function.
+	(linux_supports_vfork_events): New function.
+	(linux_target_ops): Initialize new structure members.
+	(initialize_low): Call linux_check_ptrace_features.
+	* lynx-low.c (lynx_target_ops): Initialize new structure
+	members.
+	* server.c (report_fork_events, report_vfork_events):
+	New global flags.
+	(handle_query): Add new features to qSupported packet and
+	response.
+	(captured_main): Initialize new global variables.
+	* target.h (struct target_ops) <supports_fork_events>:
+	New member.
+	<supports_vfork_events>: New member.
+	(target_supports_fork_events): New macro.
+	(target_supports_vfork_events): New macro.
+	* win32-low.c (win32_target_ops): Initialize new structure
+	members.
+
 2015-05-12  Gary Benson <gbenson@redhat.com>
 
 	* server.c (handle_qxfer_exec_file): Use current process
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index bc76ffc..1724b54 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -5438,6 +5438,22 @@ linux_supports_multi_process (void)
   return 1;
 }
 
+/* Check if fork events are supported.  */
+
+static int
+linux_supports_fork_events (void)
+{
+  return linux_supports_tracefork ();
+}
+
+/* Check if vfork events are supported.  */
+
+static int
+linux_supports_vfork_events (void)
+{
+  return linux_supports_tracefork ();
+}
+
 static int
 linux_supports_disable_randomization (void)
 {
@@ -6411,6 +6427,8 @@ static struct target_ops linux_target_ops = {
   linux_async,
   linux_start_non_stop,
   linux_supports_multi_process,
+  linux_supports_fork_events,
+  linux_supports_vfork_events,
 #ifdef USE_THREAD_DB
   thread_db_handle_monitor_command,
 #else
@@ -6488,4 +6506,6 @@ initialize_low (void)
   sigaction (SIGCHLD, &sigchld_action, NULL);
 
   initialize_low_arch ();
+
+  linux_check_ptrace_features ();
 }
diff --git a/gdb/gdbserver/lynx-low.c b/gdb/gdbserver/lynx-low.c
index 364c79f..f087416 100644
--- a/gdb/gdbserver/lynx-low.c
+++ b/gdb/gdbserver/lynx-low.c
@@ -762,6 +762,8 @@ static struct target_ops lynx_target_ops = {
   NULL,  /* async */
   NULL,  /* start_non_stop */
   NULL,  /* supports_multi_process */
+  NULL,  /* supports_fork_events */
+  NULL,  /* supports_vfork_events */
   NULL,  /* handle_monitor_command */
 };
 
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 174ab39..1544e99 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -57,6 +57,8 @@ static int exit_requested;
 int run_once;
 
 int multi_process;
+int report_fork_events;
+int report_vfork_events;
 int non_stop;
 int swbreak_feature;
 int hwbreak_feature;
@@ -2046,6 +2048,18 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 		  if (target_supports_stopped_by_hw_breakpoint ())
 		    hwbreak_feature = 1;
 		}
+	      else if (strcmp (p, "fork-events+") == 0)
+		{
+		  /* GDB supports and wants fork events if possible.  */
+		  if (target_supports_fork_events ())
+		    report_fork_events = 1;
+		}
+	      else if (strcmp (p, "vfork-events+") == 0)
+		{
+		  /* GDB supports and wants vfork events if possible.  */
+		  if (target_supports_vfork_events ())
+		    report_vfork_events = 1;
+		}
 	      else
 		target_process_qsupported (p);
 
@@ -2096,6 +2110,12 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       if (target_supports_multi_process ())
 	strcat (own_buf, ";multiprocess+");
 
+      if (target_supports_fork_events ())
+	strcat (own_buf, ";fork-events+");
+
+      if (target_supports_vfork_events ())
+	strcat (own_buf, ";vfork-events+");
+
       if (target_supports_non_stop ())
 	strcat (own_buf, ";QNonStop+");
 
@@ -3472,6 +3492,8 @@ captured_main (int argc, char *argv[])
 
       noack_mode = 0;
       multi_process = 0;
+      report_fork_events = 0;
+      report_vfork_events = 0;
       /* Be sure we're out of tfind mode.  */
       current_traceframe = -1;
       cont_thread = null_ptid;
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index b3d08cd..697b223 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -281,6 +281,12 @@ struct target_ops
   /* Returns true if the target supports multi-process debugging.  */
   int (*supports_multi_process) (void);
 
+  /* Returns true if fork events are supported.  */
+  int (*supports_fork_events) (void);
+
+  /* Returns true if vfork events are supported.  */
+  int (*supports_vfork_events) (void);
+
   /* If not NULL, target-specific routine to process monitor command.
      Returns 1 if handled, or 0 to perform default processing.  */
   int (*handle_monitor_command) (char *);
@@ -420,6 +426,14 @@ void set_target_ops (struct target_ops *);
 
 int kill_inferior (int);
 
+#define target_supports_fork_events() \
+  (the_target->supports_fork_events ? \
+   (*the_target->supports_fork_events) () : 0)
+
+#define target_supports_vfork_events() \
+  (the_target->supports_vfork_events ? \
+   (*the_target->supports_vfork_events) () : 0)
+
 #define detach_inferior(pid) \
   (*the_target->detach) (pid)
 
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 6cf56bd..a58f963 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -1831,6 +1831,8 @@ static struct target_ops win32_target_ops = {
   NULL, /* async */
   NULL, /* start_non_stop */
   NULL, /* supports_multi_process */
+  NULL, /* supports_fork_events */
+  NULL, /* supports_vfork_events */
   NULL, /* handle_monitor_command */
   NULL, /* core_of_thread */
   NULL, /* read_loadmap */
diff --git a/gdb/nat/linux-ptrace.c b/gdb/nat/linux-ptrace.c
index 2244d9d..aba3da8 100644
--- a/gdb/nat/linux-ptrace.c
+++ b/gdb/nat/linux-ptrace.c
@@ -337,7 +337,7 @@ static void linux_test_for_exitkill (int child_pid);
 
 /* Determine ptrace features available on this target.  */
 
-static void
+void
 linux_check_ptrace_features (void)
 {
   int child_pid, ret, status;
diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h
index 8354a4d..03d98c9 100644
--- a/gdb/nat/linux-ptrace.h
+++ b/gdb/nat/linux-ptrace.h
@@ -149,6 +149,7 @@ extern void linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer);
 extern char *linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err);
 
 extern void linux_ptrace_init_warnings (void);
+extern void linux_check_ptrace_features (void);
 extern void linux_enable_event_reporting (pid_t pid, int attached);
 extern void linux_disable_event_reporting (pid_t pid);
 extern int linux_supports_tracefork (void);
diff --git a/gdb/remote.c b/gdb/remote.c
index 02c8371..6dae920 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -1342,6 +1342,12 @@ enum {
   /* Support for hwbreak+ feature.  */
   PACKET_hwbreak_feature,
 
+  /* Support for fork events.  */
+  PACKET_fork_event_feature,
+
+  /* Support for vfork events.  */
+  PACKET_vfork_event_feature,
+
   PACKET_MAX
 };
 
@@ -4051,6 +4057,10 @@ static const struct protocol_feature remote_protocol_features[] = {
     PACKET_Qbtrace_conf_bts_size },
   { "swbreak", PACKET_DISABLE, remote_supported_packet, PACKET_swbreak_feature },
   { "hwbreak", PACKET_DISABLE, remote_supported_packet, PACKET_hwbreak_feature },
+  { "fork-events", PACKET_DISABLE, remote_supported_packet,
+    PACKET_fork_event_feature },
+  { "vfork-events", PACKET_DISABLE, remote_supported_packet,
+    PACKET_vfork_event_feature },
 };
 
 static char *remote_support_xml;
@@ -4129,6 +4139,16 @@ remote_query_supported (void)
 
       q = remote_query_supported_append (q, "qRelocInsn+");
 
+      if (rs->extended)
+	{
+	  if (packet_set_cmd_state (PACKET_fork_event_feature)
+	      != AUTO_BOOLEAN_FALSE)
+	    q = remote_query_supported_append (q, "fork-events+");
+	  if (packet_set_cmd_state (PACKET_vfork_event_feature)
+	      != AUTO_BOOLEAN_FALSE)
+	    q = remote_query_supported_append (q, "vfork-events+");
+	}
+
       q = reconcat (q, "qSupported:", q, (char *) NULL);
       putpkt (q);
 
@@ -12434,6 +12454,12 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL,
   add_packet_config_cmd (&remote_protocol_packets[PACKET_hwbreak_feature],
                          "hwbreak-feature", "hwbreak-feature", 0);
 
+  add_packet_config_cmd (&remote_protocol_packets[PACKET_fork_event_feature],
+			 "fork-event-feature", "fork-event-feature", 0);
+
+  add_packet_config_cmd (&remote_protocol_packets[PACKET_vfork_event_feature],
+			 "vfork-event-feature", "vfork-event-feature", 0);
+
   /* Assert that we've registered "set remote foo-packet" commands
      for all packet configs.  */
   {
-- 
1.8.1.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [pushed][PATCH 4/7] Arch-specific remote follow fork
  2015-05-12 17:28 [pushed][PATCH 1/7] Identify remote fork event support Don Breazeal
                   ` (4 preceding siblings ...)
  2015-05-12 17:29 ` [pushed][PATCH 7/7] Extended-remote fork event docs Don Breazeal
@ 2015-05-12 17:29 ` Don Breazeal
  2015-05-14 10:25   ` Vidya Praveen
  5 siblings, 1 reply; 13+ messages in thread
From: Don Breazeal @ 2015-05-12 17:29 UTC (permalink / raw)
  To: gdb-patches

This is the version of the patch that I pushed.
Thanks
--Don


This patch implements the architecture-specific pieces of follow-fork
for remote and extended-remote Linux targets, which in the current
implementation copyies the parent's debug register state into the new
child's data structures.  This is required for x86, arm, aarch64, and
mips.

This follows the native implementation as closely as possible by
implementing a new linux_target_ops function 'new_fork', which is
analogous to 'linux_nat_new_fork' in linux-nat.c.  In gdbserver, the debug
registers are stored in the process list, instead of an
architecture-specific list, so the function arguments are process_info
pointers instead of an lwp_info and a pid as in the native implementation.

In the MIPS implementation the debug register mirror is stored differently
from x86, ARM, and aarch64, so instead of doing a simple structure assignment
I had to clone the list of watchpoint structures.

Tested using gdb.threads/watchpoint-fork.exp on x86, and ran manual tests
on a MIPS board and an ARM board.  Aarch64 hasn't been tested.

gdb/gdbserver/ChangeLog:

        * linux-aarch64-low.c (aarch64_linux_new_fork): New function.
        (the_low_target) <new_fork>: Initialize new member.
        * linux-arm-low.c (arm_new_fork): New function.
        (the_low_target) <new_fork>: Initialize new member.
        * linux-low.c (handle_extended_wait): Call new target function
        new_fork.
        * linux-low.h (struct linux_target_ops) <new_fork>: New member.
        * linux-mips-low.c (mips_add_watchpoint): New function
        extracted from mips_insert_point.
        (the_low_target) <new_fork>: Initialize new member.
        (mips_linux_new_fork): New function.
        (mips_insert_point): Call mips_add_watchpoint.
        * linux-x86-low.c (x86_linux_new_fork): New function.
        (the_low_target) <new_fork>: Initialize new member.
---
 gdb/gdbserver/ChangeLog           | 17 +++++++++
 gdb/gdbserver/linux-aarch64-low.c | 28 +++++++++++++++
 gdb/gdbserver/linux-arm-low.c     | 42 ++++++++++++++++++++++
 gdb/gdbserver/linux-low.c         |  4 +++
 gdb/gdbserver/linux-low.h         |  3 ++
 gdb/gdbserver/linux-mips-low.c    | 76 ++++++++++++++++++++++++++++++++-------
 gdb/gdbserver/linux-x86-low.c     | 29 +++++++++++++++
 7 files changed, 187 insertions(+), 12 deletions(-)

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 0ef695c..0bdcdf3 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,22 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* linux-aarch64-low.c (aarch64_linux_new_fork): New function.
+	(the_low_target) <new_fork>: Initialize new member.
+	* linux-arm-low.c (arm_new_fork): New function.
+	(the_low_target) <new_fork>: Initialize new member.
+	* linux-low.c (handle_extended_wait): Call new target function
+	new_fork.
+	* linux-low.h (struct linux_target_ops) <new_fork>: New member.
+	* linux-mips-low.c (mips_add_watchpoint): New function
+	extracted from mips_insert_point.
+	(the_low_target) <new_fork>: Initialize new member.
+	(mips_linux_new_fork): New function.
+	(mips_insert_point): Call mips_add_watchpoint.
+	* linux-x86-low.c (x86_linux_new_fork): New function.
+	(the_low_target) <new_fork>: Initialize new member.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* linux-low.c (handle_extended_wait): Implement return value,
 	rename argument 'event_child' to 'event_lwp', handle
 	PTRACE_EVENT_FORK, call internal_error for unrecognized event.
diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c
index d44175e..7e6e9ac 100644
--- a/gdb/gdbserver/linux-aarch64-low.c
+++ b/gdb/gdbserver/linux-aarch64-low.c
@@ -1135,6 +1135,33 @@ aarch64_linux_new_thread (struct lwp_info *lwp)
   lwp->arch_private = info;
 }
 
+static void
+aarch64_linux_new_fork (struct process_info *parent,
+			struct process_info *child)
+{
+  /* These are allocated by linux_add_process.  */
+  gdb_assert (parent->private != NULL
+	      && parent->private->arch_private != NULL);
+  gdb_assert (child->private != NULL
+	      && child->private->arch_private != NULL);
+
+  /* Linux kernel before 2.6.33 commit
+     72f674d203cd230426437cdcf7dd6f681dad8b0d
+     will inherit hardware debug registers from parent
+     on fork/vfork/clone.  Newer Linux kernels create such tasks with
+     zeroed debug registers.
+
+     GDB core assumes the child inherits the watchpoints/hw
+     breakpoints of the parent, and will remove them all from the
+     forked off process.  Copy the debug registers mirrors into the
+     new process so that all breakpoints and watchpoints can be
+     removed together.  The debug registers mirror will become zeroed
+     in the end before detaching the forked off process, thus making
+     this compatible with older Linux kernels too.  */
+
+  *child->private->arch_private = *parent->private->arch_private;
+}
+
 /* Called when resuming a thread.
    If the debug regs have changed, update the thread's copies.  */
 
@@ -1299,6 +1326,7 @@ struct linux_target_ops the_low_target =
   NULL,
   aarch64_linux_new_process,
   aarch64_linux_new_thread,
+  aarch64_linux_new_fork,
   aarch64_linux_prepare_to_resume,
 };
 
diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index d408dcd..3420dea 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -717,6 +717,47 @@ arm_new_thread (struct lwp_info *lwp)
   lwp->arch_private = info;
 }
 
+static void
+arm_new_fork (struct process_info *parent, struct process_info *child)
+{
+  struct arch_process_info *parent_proc_info = parent->private->arch_private;
+  struct arch_process_info *child_proc_info = child->private->arch_private;
+  struct lwp_info *child_lwp;
+  struct arch_lwp_info *child_lwp_info;
+  int i;
+
+  /* These are allocated by linux_add_process.  */
+  gdb_assert (parent->private != NULL
+	      && parent->private->arch_private != NULL);
+  gdb_assert (child->private != NULL
+	      && child->private->arch_private != NULL);
+
+  /* Linux kernel before 2.6.33 commit
+     72f674d203cd230426437cdcf7dd6f681dad8b0d
+     will inherit hardware debug registers from parent
+     on fork/vfork/clone.  Newer Linux kernels create such tasks with
+     zeroed debug registers.
+
+     GDB core assumes the child inherits the watchpoints/hw
+     breakpoints of the parent, and will remove them all from the
+     forked off process.  Copy the debug registers mirrors into the
+     new process so that all breakpoints and watchpoints can be
+     removed together.  The debug registers mirror will become zeroed
+     in the end before detaching the forked off process, thus making
+     this compatible with older Linux kernels too.  */
+
+  *child_proc_info = *parent_proc_info;
+
+  /* Mark all the hardware breakpoints and watchpoints as changed to
+     make sure that the registers will be updated.  */
+  child_lwp = find_lwp_pid (ptid_of (child));
+  child_lwp_info = child_lwp->arch_private;
+  for (i = 0; i < MAX_BPTS; i++)
+    child_lwp_info->bpts_changed[i] = 1;
+  for (i = 0; i < MAX_WPTS; i++)
+    child_lwp_info->wpts_changed[i] = 1;
+}
+
 /* Called when resuming a thread.
    If the debug regs have changed, update the thread's copies.  */
 static void
@@ -920,6 +961,7 @@ struct linux_target_ops the_low_target = {
   NULL, /* siginfo_fixup */
   arm_new_process,
   arm_new_thread,
+  arm_new_fork,
   arm_prepare_to_resume,
 };
 
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index b280c17..d9053ad 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -489,6 +489,10 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat)
 	  child_proc->tdesc = tdesc;
 	  child_lwp->must_set_ptrace_flags = 1;
 
+	  /* Clone arch-specific process data.  */
+	  if (the_low_target.new_fork != NULL)
+	    the_low_target.new_fork (parent_proc, child_proc);
+
 	  /* Save fork info in the parent thread.  */
 	  event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED;
 	  event_lwp->waitstatus.value.related_pid = ptid;
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index 41067d6..3300da9 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -187,6 +187,9 @@ struct linux_target_ops
      allocate it here.  */
   void (*new_thread) (struct lwp_info *);
 
+  /* Hook to call, if any, when a new fork is attached.  */
+  void (*new_fork) (struct process_info *parent, struct process_info *child);
+
   /* Hook to call prior to resuming a thread.  */
   void (*prepare_to_resume) (struct lwp_info *);
 
diff --git a/gdb/gdbserver/linux-mips-low.c b/gdb/gdbserver/linux-mips-low.c
index 7988d07..4601ad0 100644
--- a/gdb/gdbserver/linux-mips-low.c
+++ b/gdb/gdbserver/linux-mips-low.c
@@ -344,6 +344,68 @@ mips_linux_new_thread (struct lwp_info *lwp)
   lwp->arch_private = info;
 }
 
+/* Create a new mips_watchpoint and add it to the list.  */
+
+static void
+mips_add_watchpoint (struct arch_process_info *private, CORE_ADDR addr,
+		     int len, int watch_type)
+{
+  struct mips_watchpoint *new_watch;
+  struct mips_watchpoint **pw;
+
+  new_watch = xmalloc (sizeof (struct mips_watchpoint));
+  new_watch->addr = addr;
+  new_watch->len = len;
+  new_watch->type = watch_type;
+  new_watch->next = NULL;
+
+  pw = &private->current_watches;
+  while (*pw != NULL)
+    pw = &(*pw)->next;
+  *pw = new_watch;
+}
+
+/* Hook to call when a new fork is attached.  */
+
+static void
+mips_linux_new_fork (struct process_info *parent,
+			struct process_info *child)
+{
+  struct arch_process_info *parent_private;
+  struct arch_process_info *child_private;
+  struct mips_watchpoint *wp;
+
+  /* These are allocated by linux_add_process.  */
+  gdb_assert (parent->private != NULL
+	      && parent->private->arch_private != NULL);
+  gdb_assert (child->private != NULL
+	      && child->private->arch_private != NULL);
+
+  /* Linux kernel before 2.6.33 commit
+     72f674d203cd230426437cdcf7dd6f681dad8b0d
+     will inherit hardware debug registers from parent
+     on fork/vfork/clone.  Newer Linux kernels create such tasks with
+     zeroed debug registers.
+
+     GDB core assumes the child inherits the watchpoints/hw
+     breakpoints of the parent, and will remove them all from the
+     forked off process.  Copy the debug registers mirrors into the
+     new process so that all breakpoints and watchpoints can be
+     removed together.  The debug registers mirror will become zeroed
+     in the end before detaching the forked off process, thus making
+     this compatible with older Linux kernels too.  */
+
+  parent_private = parent->private->arch_private;
+  child_private = child->private->arch_private;
+
+  child_private->watch_readback_valid = parent_private->watch_readback_valid;
+  child_private->watch_readback = parent_private->watch_readback;
+
+  for (wp = parent_private->current_watches; wp != NULL; wp = wp->next)
+    mips_add_watchpoint (child_private, wp->addr, wp->len, wp->type);
+
+  child_private->watch_mirror = parent_private->watch_mirror;
+}
 /* This is the implementation of linux_target_ops method
    prepare_to_resume.  If the watch regs have changed, update the
    thread's copies.  */
@@ -397,8 +459,6 @@ mips_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
   struct process_info *proc = current_process ();
   struct arch_process_info *priv = proc->priv->arch_private;
   struct pt_watch_regs regs;
-  struct mips_watchpoint *new_watch;
-  struct mips_watchpoint **pw;
   int pid;
   long lwpid;
   enum target_hw_bp_type watch_type;
@@ -425,16 +485,7 @@ mips_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
     return -1;
 
   /* It fit.  Stick it on the end of the list.  */
-  new_watch = xmalloc (sizeof (struct mips_watchpoint));
-  new_watch->addr = addr;
-  new_watch->len = len;
-  new_watch->type = watch_type;
-  new_watch->next = NULL;
-
-  pw = &priv->current_watches;
-  while (*pw != NULL)
-    pw = &(*pw)->next;
-  *pw = new_watch;
+  mips_add_watchpoint (priv, addr, len, watch_type);
 
   priv->watch_mirror = regs;
 
@@ -845,6 +896,7 @@ struct linux_target_ops the_low_target = {
   NULL, /* siginfo_fixup */
   mips_linux_new_process,
   mips_linux_new_thread,
+  mips_linux_new_fork,
   mips_linux_prepare_to_resume
 };
 
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 763df08..4aef7b7 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -634,6 +634,34 @@ x86_linux_new_process (void)
   return info;
 }
 
+/* Target routine for linux_new_fork.  */
+
+static void
+x86_linux_new_fork (struct process_info *parent, struct process_info *child)
+{
+  /* These are allocated by linux_add_process.  */
+  gdb_assert (parent->priv != NULL
+	      && parent->priv->arch_private != NULL);
+  gdb_assert (child->priv != NULL
+	      && child->priv->arch_private != NULL);
+
+  /* Linux kernel before 2.6.33 commit
+     72f674d203cd230426437cdcf7dd6f681dad8b0d
+     will inherit hardware debug registers from parent
+     on fork/vfork/clone.  Newer Linux kernels create such tasks with
+     zeroed debug registers.
+
+     GDB core assumes the child inherits the watchpoints/hw
+     breakpoints of the parent, and will remove them all from the
+     forked off process.  Copy the debug registers mirrors into the
+     new process so that all breakpoints and watchpoints can be
+     removed together.  The debug registers mirror will become zeroed
+     in the end before detaching the forked off process, thus making
+     this compatible with older Linux kernels too.  */
+
+  *child->priv->arch_private = *parent->priv->arch_private;
+}
+
 /* See nat/x86-dregs.h.  */
 
 struct x86_debug_reg_state *
@@ -3263,6 +3291,7 @@ struct linux_target_ops the_low_target =
   x86_siginfo_fixup,
   x86_linux_new_process,
   x86_linux_new_thread,
+  x86_linux_new_fork,
   x86_linux_prepare_to_resume,
   x86_linux_process_qsupported,
   x86_supports_tracepoints,
-- 
1.8.1.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [pushed][PATCH 7/7] Extended-remote fork event docs
  2015-05-12 17:28 [pushed][PATCH 1/7] Identify remote fork event support Don Breazeal
                   ` (3 preceding siblings ...)
  2015-05-12 17:29 ` [pushed][PATCH 5/7] Extended-remote follow vfork Don Breazeal
@ 2015-05-12 17:29 ` Don Breazeal
  2015-05-12 17:29 ` [pushed][PATCH 4/7] Arch-specific remote follow fork Don Breazeal
  5 siblings, 0 replies; 13+ messages in thread
From: Don Breazeal @ 2015-05-12 17:29 UTC (permalink / raw)
  To: gdb-patches

This is the version of the patch that I pushed.
Thanks
--Don


This patch contains the accumulated documentation changes for the
rest of the extended-remote follow fork patchset.

gdb/ChangeLog:

        * NEWS: Announce fork support in the RSP and support
          for fork debugging in extended mode.

gdb/doc/ChangeLog:

        * gdb.texinfo (Forks): Note that fork debugging is
          supported in extended mode.
          (Remote Configuration): Add fork event features to table
          of packet settings.
          (Stop Reply Packets): Add fork events to list of stop reasons.
          (General Query Packets): Add fork events to tables of
          'gdbfeatures' and 'stub features' supported in the qSupported
          packet, as well as to the list containing stub feature
          details.
---
 gdb/ChangeLog       |  5 ++++
 gdb/NEWS            | 24 ++++++++++++++++
 gdb/doc/ChangeLog   | 12 ++++++++
 gdb/doc/gdb.texinfo | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 124 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 53d6d5d..a316b4e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* NEWS: Announce fork support in the RSP and support
+	for fork debugging in extended mode.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* remote.c (remote_insert_fork_catchpoint): New function.
 	(remote_remove_fork_catchpoint): New function.
 	(remote_insert_vfork_catchpoint): New function.
diff --git a/gdb/NEWS b/gdb/NEWS
index 51e4f4e..bf12101 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -128,6 +128,30 @@ qXfer:exec-file:read
   Return the full absolute name of the file that was executed to
   create a process running on the remote system.
 
+fork stop reason
+  Indicates that a fork system call was executed.
+
+vfork stop reason
+  Indicates that a vfork system call was executed.
+
+vforkdone stop reason
+  Indicates that a vfork child of the specified process has executed
+  an exec or exit, allowing the vfork parent to resume execution.
+
+fork-events and vfork-events features in qSupported
+  The qSupported packet allows GDB to request support for fork and 
+  vfork events using new 'gdbfeatures' fork-events and vfork-events,
+  and the qSupported response can contain the corresponding
+  'stubfeatures'.  Set and show commands can be used to display
+  whether these features are enabled.
+
+* Extended-remote fork events
+
+  ** GDB now has support for fork events on extended-remote Linux
+     targets.  For targets with Linux kernels 2.5.60 and later, this
+     enables follow-fork-mode and detach-on-fork for both fork and
+     vfork, as well as fork and vfork catchpoints.
+
 * The info record command now shows the recording format and the
   branch tracing configuration for the current thread when using
   the btrace record target.
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 05aeab7..849deb8 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,15 @@
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
+	* gdb.texinfo (Forks): Note that fork debugging is
+	supported in extended mode.
+	(Remote Configuration): Add fork event features to table
+	of packet settings.
+	(Stop Reply Packets): Add fork events to list of stop reasons.
+	(General Query Packets): Add fork events to tables of
+	'gdbfeatures' and 'stub features' supported in the qSupported
+	packet, as well as to the list containing stub feature
+	details.
+
 2015-05-12  Gary Benson <gbenson@redhat.com>
 
 	* gdb.texinfo (General Query Packets): Document
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 5461356..cb9cd35 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -3135,6 +3135,9 @@ create additional processes using the @code{fork} or @code{vfork} functions.
 Currently, the only platforms with this feature are HP-UX (11.x and later
 only?) and @sc{gnu}/Linux (kernel version 2.5.60 and later).
 
+The fork debugging commands are supported in both native mode and when
+connected to @code{gdbserver} using @kbd{target extended-remote}.
+
 By default, when a program forks, @value{GDBN} will continue to debug
 the parent process and the child process will run unimpeded.
 
@@ -19938,6 +19941,14 @@ are:
 @tab @code{hwbreak stop reason}
 @tab @code{hbreak}
 
+@item @code{fork-event-feature}
+@tab @code{fork stop reason}
+@tab @code{fork}
+
+@item @code{vfork-event-feature}
+@tab @code{vfork stop reason}
+@tab @code{vfork}
+
 @end multitable
 
 @node Remote Stub
@@ -35372,6 +35383,49 @@ The @var{r} part must be left empty.
 
 The same remarks about @samp{qSupported} and non-stop mode above
 apply.
+
+@cindex fork events, remote reply
+@item fork
+The packet indicates that @code{fork} was called, and @var{r}
+is the thread ID of the new child process.  Refer to
+@ref{thread-id syntax} for the format of the @var{thread-id}
+field.  This packet is only applicable to targets that support
+fork events.
+
+This packet should not be sent by default; older @value{GDBN} versions
+did not support it.  @value{GDBN} requests it, by supplying an
+appropriate @samp{qSupported} feature (@pxref{qSupported}).  The
+remote stub must also supply the appropriate @samp{qSupported} feature
+indicating support.
+
+@cindex vfork events, remote reply
+@item vfork
+The packet indicates that @code{vfork} was called, and @var{r}
+is the thread ID of the new child process. Refer to
+@ref{thread-id syntax} for the format of the @var{thread-id}
+field.  This packet is only applicable to targets that support
+vfork events.
+
+This packet should not be sent by default; older @value{GDBN} versions
+did not support it.  @value{GDBN} requests it, by supplying an
+appropriate @samp{qSupported} feature (@pxref{qSupported}).  The
+remote stub must also supply the appropriate @samp{qSupported} feature
+indicating support.
+
+@cindex vforkdone events, remote reply
+@item vforkdone
+The packet indicates that a child process created by a vfork
+has either called @code{exec} or terminated, so that the
+address spaces of the parent and child process are no longer
+shared. The @var{r} part is ignored.  This packet is only
+applicable to targets that support vforkdone events.
+
+This packet should not be sent by default; older @value{GDBN} versions
+did not support it.  @value{GDBN} requests it, by supplying an
+appropriate @samp{qSupported} feature (@pxref{qSupported}).  The
+remote stub must also supply the appropriate @samp{qSupported} feature
+indicating support.
+
 @end table
 
 @item W @var{AA}
@@ -35964,6 +36018,18 @@ reason in stop replies.  @xref{swbreak stop reason}, for details.
 @item hwbreak
 This feature indicates whether @value{GDBN} supports the hwbreak stop
 reason in stop replies.  @xref{swbreak stop reason}, for details.
+
+@item fork-events
+This feature indicates whether @value{GDBN} supports fork event
+extensions to the remote protocol.  @value{GDBN} does not use such
+extensions unless the stub also reports that it supports them by
+including @samp{fork-events+} in its @samp{qSupported} reply.
+
+@item vfork-events
+This feature indicates whether @value{GDBN} supports vfork event
+extensions to the remote protocol.  @value{GDBN} does not use such
+extensions unless the stub also reports that it supports them by
+including @samp{vfork-events+} in its @samp{qSupported} reply.
 @end table
 
 Stubs should ignore any unknown values for
@@ -36207,6 +36273,16 @@ These are the currently defined stub features and their properties:
 @tab @samp{-}
 @tab No
 
+@item @samp{fork-events}
+@tab No
+@tab @samp{-}
+@tab No
+
+@item @samp{vfork-events}
+@tab No
+@tab @samp{-}
+@tab No
+
 @end multitable
 
 These are the currently defined stub features, in more detail:
@@ -36399,6 +36475,13 @@ breakpoints.
 The remote stub reports the @samp{hwbreak} stop reason for hardware
 breakpoints.
 
+@item fork-events
+The remote stub reports the @samp{fork} stop reason for fork events.
+
+@item vfork-events
+The remote stub reports the @samp{vfork} stop reason for vfork events
+and vforkdone events.
+
 @end table
 
 @item qSymbol::
-- 
1.8.1.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [pushed][PATCH 5/7] Extended-remote follow vfork
  2015-05-12 17:28 [pushed][PATCH 1/7] Identify remote fork event support Don Breazeal
                   ` (2 preceding siblings ...)
  2015-05-12 17:29 ` [pushed][PATCH 6/7] Extended-remote fork catch Don Breazeal
@ 2015-05-12 17:29 ` Don Breazeal
  2015-05-12 17:29 ` [pushed][PATCH 7/7] Extended-remote fork event docs Don Breazeal
  2015-05-12 17:29 ` [pushed][PATCH 4/7] Arch-specific remote follow fork Don Breazeal
  5 siblings, 0 replies; 13+ messages in thread
From: Don Breazeal @ 2015-05-12 17:29 UTC (permalink / raw)
  To: gdb-patches

This is the version of the patch that I pushed.
Thanks
--Don


This patch implements follow-fork for vfork on extended-remote Linux targets.

The implementation follows the native implementation as much as possible.
Most of the work is done on the GDB side in the existing code now in
infrun.c.  GDBserver just has to report the events and do a little
bookkeeping.

Implementation includes:

 * enabling VFORK events by adding ptrace options for VFORK and VFORK_DONE
   to linux-low.c:linux_low_ptrace_options.

 * handling VFORK and VFORK_DONE events in linux-low.c:handle_extended_wait
   and reporting them to GDB.

 * including VFORK and VFORK_DONE events in the predicate
   linux-low.c:extended_event_reported.

 * adding support for VFORK and VFORK_DONE events in RSP by adding stop
   reasons "vfork" and "vforkdone" to the 'T' Stop Reply Packet in both
   gdbserver/remote-utils.c and gdb/remote.c.

Tested on x64 Ubuntu Lucid, native, remote, extended-remote.

gdb/gdbserver/ChangeLog:

        * linux-low.c (handle_extended_wait): Handle PTRACE_EVENT_FORK and
        PTRACE_EVENT_VFORK_DONE.
        (linux_low_ptrace_options, extended_event_reported): Add vfork
        events.
        * remote-utils.c (prepare_resume_reply): New stop reasons "vfork"
        and "vforkdone" for RSP 'T' Stop Reply Packet.
        * server.h (report_vfork_events): Declare
        global variable.

gdb/ChangeLog:

        * remote.c (remove_vfork_event_p): New function.
        (remote_follow_fork): Add vfork event type to event checking.
        (remote_parse_stop_reply): New stop reasons "vfork" and
        "vforkdone" for RSP 'T' Stop Reply Packet.
---
 gdb/ChangeLog                |  7 +++++++
 gdb/gdbserver/ChangeLog      | 11 +++++++++++
 gdb/gdbserver/linux-low.c    | 26 ++++++++++++++++++++++----
 gdb/gdbserver/remote-utils.c | 18 ++++++++++++++++--
 gdb/gdbserver/server.h       |  1 +
 gdb/remote.c                 | 22 +++++++++++++++++++++-
 6 files changed, 78 insertions(+), 7 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c9c2e62..e84f23f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* remote.c (remove_vfork_event_p): New function.
+	(remote_follow_fork): Add vfork event type to event checking.
+	(remote_parse_stop_reply): New stop reasons "vfork" and
+	"vforkdone" for RSP 'T' Stop Reply Packet.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* linux-nat.c (linux_nat_ptrace_options): New function.
 	(linux_init_ptrace, wait_lwp, linux_nat_filter_event):
 	Call linux_nat_ptrace_options and use different argument to
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 0bdcdf3..1e20a36 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,16 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* linux-low.c (handle_extended_wait): Handle PTRACE_EVENT_FORK and
+	PTRACE_EVENT_VFORK_DONE.
+	(linux_low_ptrace_options, extended_event_reported): Add vfork
+	events.
+	* remote-utils.c (prepare_resume_reply): New stop reasons "vfork"
+	and "vforkdone" for RSP 'T' Stop Reply Packet.
+	* server.h (report_vfork_events): Declare
+	global variable.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* linux-aarch64-low.c (aarch64_linux_new_fork): New function.
 	(the_low_target) <new_fork>: Initialize new member.
 	* linux-arm-low.c (arm_new_fork): New function.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index d9053ad..9f3ea48 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -425,7 +425,8 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat)
   struct thread_info *event_thr = get_lwp_thread (event_lwp);
   struct lwp_info *new_lwp;
 
-  if ((event == PTRACE_EVENT_FORK) || (event == PTRACE_EVENT_CLONE))
+  if ((event == PTRACE_EVENT_FORK) || (event == PTRACE_EVENT_VFORK)
+      || (event == PTRACE_EVENT_CLONE))
     {
       ptid_t ptid;
       unsigned long new_pid;
@@ -451,7 +452,7 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat)
 	    warning ("wait returned unexpected status 0x%x", status);
 	}
 
-      if (event == PTRACE_EVENT_FORK)
+      if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
 	{
 	  struct process_info *parent_proc;
 	  struct process_info *child_proc;
@@ -494,8 +495,13 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat)
 	    the_low_target.new_fork (parent_proc, child_proc);
 
 	  /* Save fork info in the parent thread.  */
-	  event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED;
+	  if (event == PTRACE_EVENT_FORK)
+	    event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED;
+	  else if (event == PTRACE_EVENT_VFORK)
+	    event_lwp->waitstatus.kind = TARGET_WAITKIND_VFORKED;
+
 	  event_lwp->waitstatus.value.related_pid = ptid;
+
 	  /* The status_pending field contains bits denoting the
 	     extended event, so when the pending event is handled,
 	     the handler will look at lwp->waitstatus.  */
@@ -538,6 +544,13 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat)
       /* Don't report the event.  */
       return 1;
     }
+  else if (event == PTRACE_EVENT_VFORK_DONE)
+    {
+      event_lwp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
+
+      /* Report the event.  */
+      return 0;
+    }
 
   internal_error (__FILE__, __LINE__, _("unknown ptrace event %d"), event);
 }
@@ -2010,6 +2023,9 @@ linux_low_ptrace_options (int attached)
   if (report_fork_events)
     options |= PTRACE_O_TRACEFORK;
 
+  if (report_vfork_events)
+    options |= (PTRACE_O_TRACEVFORK | PTRACE_O_TRACEVFORKDONE);
+
   return options;
 }
 
@@ -2714,7 +2730,9 @@ extended_event_reported (const struct target_waitstatus *waitstatus)
   if (waitstatus == NULL)
     return 0;
 
-  return (waitstatus->kind == TARGET_WAITKIND_FORKED);
+  return (waitstatus->kind == TARGET_WAITKIND_FORKED
+	  || waitstatus->kind == TARGET_WAITKIND_VFORKED
+	  || waitstatus->kind == TARGET_WAITKIND_VFORK_DONE);
 }
 
 /* Wait for process, returns status.  */
diff --git a/gdb/gdbserver/remote-utils.c b/gdb/gdbserver/remote-utils.c
index 6078348..bb31456 100644
--- a/gdb/gdbserver/remote-utils.c
+++ b/gdb/gdbserver/remote-utils.c
@@ -1115,16 +1115,20 @@ prepare_resume_reply (char *buf, ptid_t ptid,
     {
     case TARGET_WAITKIND_STOPPED:
     case TARGET_WAITKIND_FORKED:
+    case TARGET_WAITKIND_VFORKED:
       {
 	struct thread_info *saved_thread;
 	const char **regp;
 	struct regcache *regcache;
 
-	if (status->kind == TARGET_WAITKIND_FORKED && report_fork_events)
+	if ((status->kind == TARGET_WAITKIND_FORKED && report_fork_events)
+	    || (status->kind == TARGET_WAITKIND_VFORKED && report_vfork_events))
 	  {
 	    enum gdb_signal signal = GDB_SIGNAL_TRAP;
+	    const char *event = (status->kind == TARGET_WAITKIND_FORKED
+				 ? "fork" : "vfork");
 
-	    sprintf (buf, "T%02xfork:", signal);
+	    sprintf (buf, "T%02x%s:", signal, event);
 	    buf += strlen (buf);
 	    buf = write_ptid (buf, status->value.related_pid);
 	    strcat (buf, ";");
@@ -1244,6 +1248,16 @@ prepare_resume_reply (char *buf, ptid_t ptid,
       else
 	sprintf (buf, "X%02x", status->value.sig);
       break;
+    case TARGET_WAITKIND_VFORK_DONE:
+      if (report_vfork_events)
+	{
+	  enum gdb_signal signal = GDB_SIGNAL_TRAP;
+
+	  sprintf (buf, "T%02xvforkdone:;", signal);
+	}
+      else
+	sprintf (buf, "T%02x", GDB_SIGNAL_0);
+      break;
     default:
       error ("unhandled waitkind");
       break;
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 696a24e..09a5624 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -85,6 +85,7 @@ extern int disable_packet_qfThreadInfo;
 extern int run_once;
 extern int multi_process;
 extern int report_fork_events;
+extern int report_vfork_events;
 extern int non_stop;
 
 /* True if the "swbreak+" feature is active.  In that case, GDB wants
diff --git a/gdb/remote.c b/gdb/remote.c
index 390d30d..df8fca3 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -1470,6 +1470,14 @@ remote_fork_event_p (struct remote_state *rs)
   return packet_support (PACKET_fork_event_feature) == PACKET_ENABLE;
 }
 
+/* Returns true if vfork events are supported.  */
+
+static int
+remote_vfork_event_p (struct remote_state *rs)
+{
+  return packet_support (PACKET_vfork_event_feature) == PACKET_ENABLE;
+}
+
 /* Tokens for use by the asynchronous signal handlers for SIGINT.  */
 static struct async_signal_handler *async_sigint_remote_twice_token;
 static struct async_signal_handler *async_sigint_remote_token;
@@ -4537,8 +4545,10 @@ remote_follow_fork (struct target_ops *ops, int follow_child,
 		    int detach_fork)
 {
   struct remote_state *rs = get_remote_state ();
+  enum target_waitkind kind = inferior_thread ()->pending_follow.kind;
 
-  if (remote_fork_event_p (rs))
+  if ((kind == TARGET_WAITKIND_FORKED && remote_fork_event_p (rs))
+      || (kind == TARGET_WAITKIND_VFORKED && remote_vfork_event_p (rs)))
     {
       /* When following the parent and detaching the child, we detach
 	 the child here.  For the case of following the child and
@@ -5727,6 +5737,16 @@ Packet: '%s'\n"),
 	      event->ws.value.related_pid = read_ptid (++p1, &p);
 	      event->ws.kind = TARGET_WAITKIND_FORKED;
 	    }
+	  else if (strncmp (p, "vfork", p1 - p) == 0)
+	    {
+	      event->ws.value.related_pid = read_ptid (++p1, &p);
+	      event->ws.kind = TARGET_WAITKIND_VFORKED;
+	    }
+	  else if (strncmp (p, "vforkdone", p1 - p) == 0)
+	    {
+	      event->ws.kind = TARGET_WAITKIND_VFORK_DONE;
+	      p = skip_to_semicolon (p1 + 1);
+	    }
 	  else
 	    {
 	      ULONGEST pnum;
-- 
1.8.1.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [pushed][PATCH 6/7] Extended-remote fork catch
  2015-05-12 17:28 [pushed][PATCH 1/7] Identify remote fork event support Don Breazeal
  2015-05-12 17:28 ` [pushed][PATCH 3/7] Extended-remote Linux follow fork Don Breazeal
  2015-05-12 17:28 ` [pushed][PATCH 2/7] Clone remote breakpoints Don Breazeal
@ 2015-05-12 17:29 ` Don Breazeal
  2015-05-14 22:11   ` Sergio Durigan Junior
  2015-05-12 17:29 ` [pushed][PATCH 5/7] Extended-remote follow vfork Don Breazeal
                   ` (2 subsequent siblings)
  5 siblings, 1 reply; 13+ messages in thread
From: Don Breazeal @ 2015-05-12 17:29 UTC (permalink / raw)
  To: gdb-patches

This is the version of the patch that I pushed.
Thanks
--Don


This patch implements catchpoints for fork events on extended-remote
Linux targets.

Implementation appeared to be straightforward, requiring four new functions
in remote.c to implement insert/remove of fork/vfork catchpoints.  These
functions are essentially stubs that just return 0 ('success') if the
required features are enabled.  If the fork events are being reported, then
catchpoints are set and hit.

However, there are some extra issues that arise with catchpoints.

1) Thread creation reporting -- fork catchpoints are hit before the
   follow_fork has been completed.  When stopped at a fork catchpoint
   in the native implementation, the new process is not 'reported'
   until after the follow is done.  It doesn't show up in the inferiors
   list or the threads list.  However, in the gdbserver case, an
   'info threads' while stopped at a fork catchpoint will retrieve the
   new thread info from the target and add it to GDB's data structures,
   prior to the follow operations.  Because of this premature report,
   things on the GDB side eventually get very confused.

   So in remote.c:remote_update_thread_list, we check to see if there
   are any pending fork parent threads.  If there are we remove the
   related fork child thread from the thread list sent by the target.

2) Kill process before fork is followed -- on the native side in
   linux-nat.c:linux_nat_kill, there is some code to handle the case where
   a fork has occurred but follow_fork hasn't been called yet.  It does
   this by using the last status to determine if a follow is pending, and
   if it is, to kill the child task.  The use of last_status is fragile
   in situations like non-stop mode where other events may have occurred
   after the fork event.  This patch identifies a fork parent
   in remote.c:extended_remote_kill in a way similar to that used in
   thread creation reporting above.  If one is found, it kills the new
   child as well.

Tested on x64 Ubuntu Lucid, native, remote, extended-remote.  Tested the
case of killing the forking process before the fork has been followed
manually.

gdb/ChangeLog:
        * remote.c (remote_insert_fork_catchpoint): New function.
        (remote_remove_fork_catchpoint): New function.
        (remote_insert_vfork_catchpoint): New function.
        (remote_remove_vfork_catchpoint): New function.
        (pending_fork_parent_callback): New function.
        (remove_new_fork_child): New function.
        (remote_update_thread_list): Call remote_notif_get_pending_events
        and remove_new_fork_child.
        (extended_remote_kill): Kill fork child when killing the
        parent before follow_fork completes.
        (init_extended_remote_ops): Initialize target vector with
        new fork catchpoint functions.
---
 gdb/ChangeLog |  15 ++++
 gdb/remote.c  | 229 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 241 insertions(+), 3 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e84f23f..53d6d5d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,20 @@
 2015-05-12  Don Breazeal  <donb@codesourcery.com>
 
+	* remote.c (remote_insert_fork_catchpoint): New function.
+	(remote_remove_fork_catchpoint): New function.
+	(remote_insert_vfork_catchpoint): New function.
+	(remote_remove_vfork_catchpoint): New function.
+	(pending_fork_parent_callback): New function.
+	(remove_new_fork_child): New function.
+	(remote_update_thread_list): Call remote_notif_get_pending_events
+	and remove_new_fork_child.
+	(extended_remote_kill): Kill fork child when killing the
+	parent before follow_fork completes.
+	(init_extended_remote_ops): Initialize target vector with
+	new fork catchpoint functions.
+
+2015-05-12  Don Breazeal  <donb@codesourcery.com>
+
 	* remote.c (remove_vfork_event_p): New function.
 	(remote_follow_fork): Add vfork event type to event checking.
 	(remote_parse_stop_reply): New stop reasons "vfork" and
diff --git a/gdb/remote.c b/gdb/remote.c
index df8fca3..dfe115b 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -104,6 +104,10 @@ static void remote_open_1 (const char *, int, struct target_ops *,
 
 static void remote_close (struct target_ops *self);
 
+struct remote_state;
+
+static int remote_vkill (int pid, struct remote_state *rs);
+
 static void remote_mourn (struct target_ops *ops);
 
 static void extended_remote_restart (void);
@@ -181,7 +185,6 @@ static ptid_t read_ptid (char *buf, char **obuf);
 
 static void remote_set_permissions (struct target_ops *self);
 
-struct remote_state;
 static int remote_get_trace_status (struct target_ops *self,
 				    struct trace_status *ts);
 
@@ -204,6 +207,9 @@ static void push_stop_reply (struct stop_reply *);
 static void discard_pending_stop_replies_in_queue (struct remote_state *);
 static int peek_stop_reply (ptid_t ptid);
 
+struct threads_listing_context;
+static void remove_new_fork_children (struct threads_listing_context *);
+
 static void remote_async_inferior_event_handler (gdb_client_data);
 
 static void remote_terminal_ours (struct target_ops *self);
@@ -1478,6 +1484,46 @@ remote_vfork_event_p (struct remote_state *rs)
   return packet_support (PACKET_vfork_event_feature) == PACKET_ENABLE;
 }
 
+/* Insert fork catchpoint target routine.  If fork events are enabled
+   then return success, nothing more to do.  */
+
+static int
+remote_insert_fork_catchpoint (struct target_ops *ops, int pid)
+{
+  struct remote_state *rs = get_remote_state ();
+
+  return !remote_fork_event_p (rs);
+}
+
+/* Remove fork catchpoint target routine.  Nothing to do, just
+   return success.  */
+
+static int
+remote_remove_fork_catchpoint (struct target_ops *ops, int pid)
+{
+  return 0;
+}
+
+/* Insert vfork catchpoint target routine.  If vfork events are enabled
+   then return success, nothing more to do.  */
+
+static int
+remote_insert_vfork_catchpoint (struct target_ops *ops, int pid)
+{
+  struct remote_state *rs = get_remote_state ();
+
+  return !remote_vfork_event_p (rs);
+}
+
+/* Remove vfork catchpoint target routine.  Nothing to do, just
+   return success.  */
+
+static int
+remote_remove_vfork_catchpoint (struct target_ops *ops, int pid)
+{
+  return 0;
+}
+
 /* Tokens for use by the asynchronous signal handlers for SIGINT.  */
 static struct async_signal_handler *async_sigint_remote_twice_token;
 static struct async_signal_handler *async_sigint_remote_token;
@@ -2645,6 +2691,27 @@ clear_threads_listing_context (void *p)
   VEC_free (thread_item_t, context->items);
 }
 
+/* Remove the thread specified as the related_pid field of WS
+   from the CONTEXT list.  */
+
+static void
+threads_listing_context_remove (struct target_waitstatus *ws,
+				struct threads_listing_context *context)
+{
+  struct thread_item *item;
+  int i;
+  ptid_t child_ptid = ws->value.related_pid;
+
+  for (i = 0; VEC_iterate (thread_item_t, context->items, i, item); ++i)
+    {
+      if (ptid_equal (item->ptid, child_ptid))
+	{
+	  VEC_ordered_remove (thread_item_t, context->items, i);
+	  break;
+	}
+    }
+}
+
 static int
 remote_newthread_step (threadref *ref, void *data)
 {
@@ -2867,7 +2934,7 @@ remote_update_thread_list (struct target_ops *ops)
 	 target end.  Delete GDB-side threads no longer found on the
 	 target.  */
       ALL_THREADS_SAFE (tp, tmp)
-        {
+	{
 	  for (i = 0;
 	       VEC_iterate (thread_item_t, context.items, i, item);
 	       ++i)
@@ -2881,7 +2948,12 @@ remote_update_thread_list (struct target_ops *ops)
 	      /* Not found.  */
 	      delete_thread (tp->ptid);
 	    }
-        }
+	}
+
+      /* Remove any unreported fork child threads from CONTEXT so
+	 that we don't interfere with follow fork, which is where
+	 creation of such threads is handled.  */
+      remove_new_fork_children (&context);
 
       /* And now add threads we don't know about yet to our list.  */
       for (i = 0;
@@ -5427,6 +5499,81 @@ struct queue_iter_param
   struct stop_reply *output;
 };
 
+/* Determine if THREAD is a pending fork parent thread.  ARG contains
+   the pid of the process that owns the threads we want to check, or
+   -1 if we want to check all threads.  */
+
+static int
+is_pending_fork_parent (struct target_waitstatus *ws, int event_pid,
+			ptid_t thread_ptid)
+{
+  if (ws->kind == TARGET_WAITKIND_FORKED
+      || ws->kind == TARGET_WAITKIND_VFORKED)
+    {
+      if (event_pid == -1 || event_pid == ptid_get_pid (thread_ptid))
+	return 1;
+    }
+
+  return 0;
+}
+
+/* Check whether EVENT is a fork event, and if it is, remove the
+   fork child from the context list passed in DATA.  */
+
+static int
+remove_child_of_pending_fork (QUEUE (stop_reply_p) *q,
+			      QUEUE_ITER (stop_reply_p) *iter,
+			      stop_reply_p event,
+			      void *data)
+{
+  struct queue_iter_param *param = data;
+  struct threads_listing_context *context = param->input;
+
+  if (event->ws.kind == TARGET_WAITKIND_FORKED
+      || event->ws.kind == TARGET_WAITKIND_VFORKED)
+    {
+      threads_listing_context_remove (&event->ws, context);
+    }
+
+  return 1;
+}
+
+/* If CONTEXT contains any fork child threads that have not been
+   reported yet, remove them from the CONTEXT list.  If such a
+   thread exists it is because we are stopped at a fork catchpoint
+   and have not yet called follow_fork, which will set up the
+   host-side data structures for the new process.  */
+
+static void
+remove_new_fork_children (struct threads_listing_context *context)
+{
+  struct thread_info * thread;
+  int pid = -1;
+  struct notif_client *notif = &notif_client_stop;
+  struct queue_iter_param param;
+
+  /* For any threads stopped at a fork event, remove the corresponding
+     fork child threads from the CONTEXT list.  */
+  ALL_NON_EXITED_THREADS (thread)
+    {
+      struct target_waitstatus *ws = &thread->pending_follow;
+
+      if (is_pending_fork_parent (ws, pid, thread->ptid))
+	{
+	  threads_listing_context_remove (ws, context);
+	}
+    }
+
+  /* Check for any pending fork events (not reported or processed yet)
+     in process PID and remove those fork child threads from the
+     CONTEXT list as well.  */
+  remote_notif_get_pending_events (notif);
+  param.input = context;
+  param.output = NULL;
+  QUEUE_iterate (stop_reply_p, stop_reply_queue,
+		 remove_child_of_pending_fork, &param);
+}
+
 /* Remove stop replies in the queue if its pid is equal to the given
    inferior's pid.  */
 
@@ -7945,6 +8092,69 @@ getpkt_or_notif_sane (char **buf, long *sizeof_buf, int forever,
 				 is_notif);
 }
 
+/* Check whether EVENT is a fork event for the process specified
+   by the pid passed in DATA, and if it is, kill the fork child.  */
+
+static int
+kill_child_of_pending_fork (QUEUE (stop_reply_p) *q,
+			    QUEUE_ITER (stop_reply_p) *iter,
+			    stop_reply_p event,
+			    void *data)
+{
+  struct queue_iter_param *param = data;
+  int parent_pid = *(int *) param->input;
+
+  if (is_pending_fork_parent (&event->ws, parent_pid, event->ptid))
+    {
+      struct remote_state *rs = get_remote_state ();
+      int child_pid = ptid_get_pid (event->ws.value.related_pid);
+      int res;
+
+      res = remote_vkill (child_pid, rs);
+      if (res != 0)
+	error (_("Can't kill fork child process %d"), child_pid);
+    }
+
+  return 1;
+}
+
+/* Kill any new fork children of process PID that haven't been
+   processed by follow_fork.  */
+
+static void
+kill_new_fork_children (int pid, struct remote_state *rs)
+{
+  struct thread_info *thread;
+  struct notif_client *notif = &notif_client_stop;
+  struct queue_iter_param param;
+
+  /* Kill the fork child threads of any threads in process PID
+     that are stopped at a fork event.  */
+  ALL_NON_EXITED_THREADS (thread)
+    {
+      struct target_waitstatus *ws = &thread->pending_follow;
+
+      if (is_pending_fork_parent (ws, pid, thread->ptid))
+	{
+	  struct remote_state *rs = get_remote_state ();
+	  int child_pid = ptid_get_pid (ws->value.related_pid);
+	  int res;
+
+	  res = remote_vkill (child_pid, rs);
+	  if (res != 0)
+	    error (_("Can't kill fork child process %d"), child_pid);
+	}
+    }
+
+  /* Check for any pending fork events (not reported or processed yet)
+     in process PID and kill those fork child threads as well.  */
+  remote_notif_get_pending_events (notif);
+  param.input = &pid;
+  param.output = NULL;
+  QUEUE_iterate (stop_reply_p, stop_reply_queue,
+		 kill_child_of_pending_fork, &param);
+}
+
 \f
 static void
 remote_kill (struct target_ops *ops)
@@ -8014,6 +8224,11 @@ extended_remote_kill (struct target_ops *ops)
   int pid = ptid_get_pid (inferior_ptid);
   struct remote_state *rs = get_remote_state ();
 
+  /* If we're stopped while forking and we haven't followed yet, kill the
+     child task.  We need to do this before killing the parent task
+     because if this is a vfork then the parent will be sleeping.  */
+  kill_new_fork_children (pid, rs);
+
   res = remote_vkill (pid, rs);
   if (res == -1 && !(rs->extended && remote_multi_process_p (rs)))
     {
@@ -11970,6 +12185,14 @@ Specify the serial device it is connected to (e.g. /dev/ttya).";
   extended_remote_ops.to_supports_disable_randomization
     = extended_remote_supports_disable_randomization;
   extended_remote_ops.to_follow_fork = remote_follow_fork;
+  extended_remote_ops.to_insert_fork_catchpoint
+    = remote_insert_fork_catchpoint;
+  extended_remote_ops.to_remove_fork_catchpoint
+    = remote_remove_fork_catchpoint;
+  extended_remote_ops.to_insert_vfork_catchpoint
+    = remote_insert_vfork_catchpoint;
+  extended_remote_ops.to_remove_vfork_catchpoint
+    = remote_remove_vfork_catchpoint;
 }
 
 static int
-- 
1.8.1.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [pushed][PATCH 4/7] Arch-specific remote follow fork
  2015-05-12 17:29 ` [pushed][PATCH 4/7] Arch-specific remote follow fork Don Breazeal
@ 2015-05-14 10:25   ` Vidya Praveen
  2015-05-14 16:02     ` Breazeal, Don
  0 siblings, 1 reply; 13+ messages in thread
From: Vidya Praveen @ 2015-05-14 10:25 UTC (permalink / raw)
  To: Don Breazeal; +Cc: gdb-patches

Don,

There are several instances of xyz->private->arch_private where xyz
is (struct process_info*). Assume it is a typo (should've been priv
instead of private)? 

I atleast see aarch64 build of this fail.

Regards
VP.


On Tue, May 12, 2015 at 06:28:12PM +0100, Don Breazeal wrote:
> This is the version of the patch that I pushed.
> Thanks
> --Don
> 
> 
> This patch implements the architecture-specific pieces of follow-fork
> for remote and extended-remote Linux targets, which in the current
> implementation copyies the parent's debug register state into the new
> child's data structures.  This is required for x86, arm, aarch64, and
> mips.
> 
> This follows the native implementation as closely as possible by
> implementing a new linux_target_ops function 'new_fork', which is
> analogous to 'linux_nat_new_fork' in linux-nat.c.  In gdbserver, the debug
> registers are stored in the process list, instead of an
> architecture-specific list, so the function arguments are process_info
> pointers instead of an lwp_info and a pid as in the native implementation.
> 
> In the MIPS implementation the debug register mirror is stored differently
> from x86, ARM, and aarch64, so instead of doing a simple structure assignment
> I had to clone the list of watchpoint structures.
> 
> Tested using gdb.threads/watchpoint-fork.exp on x86, and ran manual tests
> on a MIPS board and an ARM board.  Aarch64 hasn't been tested.
> 
> gdb/gdbserver/ChangeLog:
> 
>         * linux-aarch64-low.c (aarch64_linux_new_fork): New function.
>         (the_low_target) <new_fork>: Initialize new member.
>         * linux-arm-low.c (arm_new_fork): New function.
>         (the_low_target) <new_fork>: Initialize new member.
>         * linux-low.c (handle_extended_wait): Call new target function
>         new_fork.
>         * linux-low.h (struct linux_target_ops) <new_fork>: New member.
>         * linux-mips-low.c (mips_add_watchpoint): New function
>         extracted from mips_insert_point.
>         (the_low_target) <new_fork>: Initialize new member.
>         (mips_linux_new_fork): New function.
>         (mips_insert_point): Call mips_add_watchpoint.
>         * linux-x86-low.c (x86_linux_new_fork): New function.
>         (the_low_target) <new_fork>: Initialize new member.
> ---
>  gdb/gdbserver/ChangeLog           | 17 +++++++++
>  gdb/gdbserver/linux-aarch64-low.c | 28 +++++++++++++++
>  gdb/gdbserver/linux-arm-low.c     | 42 ++++++++++++++++++++++
>  gdb/gdbserver/linux-low.c         |  4 +++
>  gdb/gdbserver/linux-low.h         |  3 ++
>  gdb/gdbserver/linux-mips-low.c    | 76 ++++++++++++++++++++++++++++++++-------
>  gdb/gdbserver/linux-x86-low.c     | 29 +++++++++++++++
>  7 files changed, 187 insertions(+), 12 deletions(-)
> 
> diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
> index 0ef695c..0bdcdf3 100644
> --- a/gdb/gdbserver/ChangeLog
> +++ b/gdb/gdbserver/ChangeLog
> @@ -1,5 +1,22 @@
>  2015-05-12  Don Breazeal  <donb@codesourcery.com>
> 
> +       * linux-aarch64-low.c (aarch64_linux_new_fork): New function.
> +       (the_low_target) <new_fork>: Initialize new member.
> +       * linux-arm-low.c (arm_new_fork): New function.
> +       (the_low_target) <new_fork>: Initialize new member.
> +       * linux-low.c (handle_extended_wait): Call new target function
> +       new_fork.
> +       * linux-low.h (struct linux_target_ops) <new_fork>: New member.
> +       * linux-mips-low.c (mips_add_watchpoint): New function
> +       extracted from mips_insert_point.
> +       (the_low_target) <new_fork>: Initialize new member.
> +       (mips_linux_new_fork): New function.
> +       (mips_insert_point): Call mips_add_watchpoint.
> +       * linux-x86-low.c (x86_linux_new_fork): New function.
> +       (the_low_target) <new_fork>: Initialize new member.
> +
> +2015-05-12  Don Breazeal  <donb@codesourcery.com>
> +
>         * linux-low.c (handle_extended_wait): Implement return value,
>         rename argument 'event_child' to 'event_lwp', handle
>         PTRACE_EVENT_FORK, call internal_error for unrecognized event.
> diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c
> index d44175e..7e6e9ac 100644
> --- a/gdb/gdbserver/linux-aarch64-low.c
> +++ b/gdb/gdbserver/linux-aarch64-low.c
> @@ -1135,6 +1135,33 @@ aarch64_linux_new_thread (struct lwp_info *lwp)
>    lwp->arch_private = info;
>  }
> 
> +static void
> +aarch64_linux_new_fork (struct process_info *parent,
> +                       struct process_info *child)
> +{
> +  /* These are allocated by linux_add_process.  */
> +  gdb_assert (parent->private != NULL
> +             && parent->private->arch_private != NULL);
> +  gdb_assert (child->private != NULL
> +             && child->private->arch_private != NULL);
> +
> +  /* Linux kernel before 2.6.33 commit
> +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> +     will inherit hardware debug registers from parent
> +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> +     zeroed debug registers.
> +
> +     GDB core assumes the child inherits the watchpoints/hw
> +     breakpoints of the parent, and will remove them all from the
> +     forked off process.  Copy the debug registers mirrors into the
> +     new process so that all breakpoints and watchpoints can be
> +     removed together.  The debug registers mirror will become zeroed
> +     in the end before detaching the forked off process, thus making
> +     this compatible with older Linux kernels too.  */
> +
> +  *child->private->arch_private = *parent->private->arch_private;
> +}
> +
>  /* Called when resuming a thread.
>     If the debug regs have changed, update the thread's copies.  */
> 
> @@ -1299,6 +1326,7 @@ struct linux_target_ops the_low_target =
>    NULL,
>    aarch64_linux_new_process,
>    aarch64_linux_new_thread,
> +  aarch64_linux_new_fork,
>    aarch64_linux_prepare_to_resume,
>  };
> 
> diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
> index d408dcd..3420dea 100644
> --- a/gdb/gdbserver/linux-arm-low.c
> +++ b/gdb/gdbserver/linux-arm-low.c
> @@ -717,6 +717,47 @@ arm_new_thread (struct lwp_info *lwp)
>    lwp->arch_private = info;
>  }
> 
> +static void
> +arm_new_fork (struct process_info *parent, struct process_info *child)
> +{
> +  struct arch_process_info *parent_proc_info = parent->private->arch_private;
> +  struct arch_process_info *child_proc_info = child->private->arch_private;
> +  struct lwp_info *child_lwp;
> +  struct arch_lwp_info *child_lwp_info;
> +  int i;
> +
> +  /* These are allocated by linux_add_process.  */
> +  gdb_assert (parent->private != NULL
> +             && parent->private->arch_private != NULL);
> +  gdb_assert (child->private != NULL
> +             && child->private->arch_private != NULL);
> +
> +  /* Linux kernel before 2.6.33 commit
> +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> +     will inherit hardware debug registers from parent
> +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> +     zeroed debug registers.
> +
> +     GDB core assumes the child inherits the watchpoints/hw
> +     breakpoints of the parent, and will remove them all from the
> +     forked off process.  Copy the debug registers mirrors into the
> +     new process so that all breakpoints and watchpoints can be
> +     removed together.  The debug registers mirror will become zeroed
> +     in the end before detaching the forked off process, thus making
> +     this compatible with older Linux kernels too.  */
> +
> +  *child_proc_info = *parent_proc_info;
> +
> +  /* Mark all the hardware breakpoints and watchpoints as changed to
> +     make sure that the registers will be updated.  */
> +  child_lwp = find_lwp_pid (ptid_of (child));
> +  child_lwp_info = child_lwp->arch_private;
> +  for (i = 0; i < MAX_BPTS; i++)
> +    child_lwp_info->bpts_changed[i] = 1;
> +  for (i = 0; i < MAX_WPTS; i++)
> +    child_lwp_info->wpts_changed[i] = 1;
> +}
> +
>  /* Called when resuming a thread.
>     If the debug regs have changed, update the thread's copies.  */
>  static void
> @@ -920,6 +961,7 @@ struct linux_target_ops the_low_target = {
>    NULL, /* siginfo_fixup */
>    arm_new_process,
>    arm_new_thread,
> +  arm_new_fork,
>    arm_prepare_to_resume,
>  };
> 
> diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
> index b280c17..d9053ad 100644
> --- a/gdb/gdbserver/linux-low.c
> +++ b/gdb/gdbserver/linux-low.c
> @@ -489,6 +489,10 @@ handle_extended_wait (struct lwp_info *event_lwp, int wstat)
>           child_proc->tdesc = tdesc;
>           child_lwp->must_set_ptrace_flags = 1;
> 
> +         /* Clone arch-specific process data.  */
> +         if (the_low_target.new_fork != NULL)
> +           the_low_target.new_fork (parent_proc, child_proc);
> +
>           /* Save fork info in the parent thread.  */
>           event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED;
>           event_lwp->waitstatus.value.related_pid = ptid;
> diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
> index 41067d6..3300da9 100644
> --- a/gdb/gdbserver/linux-low.h
> +++ b/gdb/gdbserver/linux-low.h
> @@ -187,6 +187,9 @@ struct linux_target_ops
>       allocate it here.  */
>    void (*new_thread) (struct lwp_info *);
> 
> +  /* Hook to call, if any, when a new fork is attached.  */
> +  void (*new_fork) (struct process_info *parent, struct process_info *child);
> +
>    /* Hook to call prior to resuming a thread.  */
>    void (*prepare_to_resume) (struct lwp_info *);
> 
> diff --git a/gdb/gdbserver/linux-mips-low.c b/gdb/gdbserver/linux-mips-low.c
> index 7988d07..4601ad0 100644
> --- a/gdb/gdbserver/linux-mips-low.c
> +++ b/gdb/gdbserver/linux-mips-low.c
> @@ -344,6 +344,68 @@ mips_linux_new_thread (struct lwp_info *lwp)
>    lwp->arch_private = info;
>  }
> 
> +/* Create a new mips_watchpoint and add it to the list.  */
> +
> +static void
> +mips_add_watchpoint (struct arch_process_info *private, CORE_ADDR addr,
> +                    int len, int watch_type)
> +{
> +  struct mips_watchpoint *new_watch;
> +  struct mips_watchpoint **pw;
> +
> +  new_watch = xmalloc (sizeof (struct mips_watchpoint));
> +  new_watch->addr = addr;
> +  new_watch->len = len;
> +  new_watch->type = watch_type;
> +  new_watch->next = NULL;
> +
> +  pw = &private->current_watches;
> +  while (*pw != NULL)
> +    pw = &(*pw)->next;
> +  *pw = new_watch;
> +}
> +
> +/* Hook to call when a new fork is attached.  */
> +
> +static void
> +mips_linux_new_fork (struct process_info *parent,
> +                       struct process_info *child)
> +{
> +  struct arch_process_info *parent_private;
> +  struct arch_process_info *child_private;
> +  struct mips_watchpoint *wp;
> +
> +  /* These are allocated by linux_add_process.  */
> +  gdb_assert (parent->private != NULL
> +             && parent->private->arch_private != NULL);
> +  gdb_assert (child->private != NULL
> +             && child->private->arch_private != NULL);
> +
> +  /* Linux kernel before 2.6.33 commit
> +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> +     will inherit hardware debug registers from parent
> +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> +     zeroed debug registers.
> +
> +     GDB core assumes the child inherits the watchpoints/hw
> +     breakpoints of the parent, and will remove them all from the
> +     forked off process.  Copy the debug registers mirrors into the
> +     new process so that all breakpoints and watchpoints can be
> +     removed together.  The debug registers mirror will become zeroed
> +     in the end before detaching the forked off process, thus making
> +     this compatible with older Linux kernels too.  */
> +
> +  parent_private = parent->private->arch_private;
> +  child_private = child->private->arch_private;
> +
> +  child_private->watch_readback_valid = parent_private->watch_readback_valid;
> +  child_private->watch_readback = parent_private->watch_readback;
> +
> +  for (wp = parent_private->current_watches; wp != NULL; wp = wp->next)
> +    mips_add_watchpoint (child_private, wp->addr, wp->len, wp->type);
> +
> +  child_private->watch_mirror = parent_private->watch_mirror;
> +}
>  /* This is the implementation of linux_target_ops method
>     prepare_to_resume.  If the watch regs have changed, update the
>     thread's copies.  */
> @@ -397,8 +459,6 @@ mips_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
>    struct process_info *proc = current_process ();
>    struct arch_process_info *priv = proc->priv->arch_private;
>    struct pt_watch_regs regs;
> -  struct mips_watchpoint *new_watch;
> -  struct mips_watchpoint **pw;
>    int pid;
>    long lwpid;
>    enum target_hw_bp_type watch_type;
> @@ -425,16 +485,7 @@ mips_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
>      return -1;
> 
>    /* It fit.  Stick it on the end of the list.  */
> -  new_watch = xmalloc (sizeof (struct mips_watchpoint));
> -  new_watch->addr = addr;
> -  new_watch->len = len;
> -  new_watch->type = watch_type;
> -  new_watch->next = NULL;
> -
> -  pw = &priv->current_watches;
> -  while (*pw != NULL)
> -    pw = &(*pw)->next;
> -  *pw = new_watch;
> +  mips_add_watchpoint (priv, addr, len, watch_type);
> 
>    priv->watch_mirror = regs;
> 
> @@ -845,6 +896,7 @@ struct linux_target_ops the_low_target = {
>    NULL, /* siginfo_fixup */
>    mips_linux_new_process,
>    mips_linux_new_thread,
> +  mips_linux_new_fork,
>    mips_linux_prepare_to_resume
>  };
> 
> diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
> index 763df08..4aef7b7 100644
> --- a/gdb/gdbserver/linux-x86-low.c
> +++ b/gdb/gdbserver/linux-x86-low.c
> @@ -634,6 +634,34 @@ x86_linux_new_process (void)
>    return info;
>  }
> 
> +/* Target routine for linux_new_fork.  */
> +
> +static void
> +x86_linux_new_fork (struct process_info *parent, struct process_info *child)
> +{
> +  /* These are allocated by linux_add_process.  */
> +  gdb_assert (parent->priv != NULL
> +             && parent->priv->arch_private != NULL);
> +  gdb_assert (child->priv != NULL
> +             && child->priv->arch_private != NULL);
> +
> +  /* Linux kernel before 2.6.33 commit
> +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> +     will inherit hardware debug registers from parent
> +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> +     zeroed debug registers.
> +
> +     GDB core assumes the child inherits the watchpoints/hw
> +     breakpoints of the parent, and will remove them all from the
> +     forked off process.  Copy the debug registers mirrors into the
> +     new process so that all breakpoints and watchpoints can be
> +     removed together.  The debug registers mirror will become zeroed
> +     in the end before detaching the forked off process, thus making
> +     this compatible with older Linux kernels too.  */
> +
> +  *child->priv->arch_private = *parent->priv->arch_private;
> +}
> +
>  /* See nat/x86-dregs.h.  */
> 
>  struct x86_debug_reg_state *
> @@ -3263,6 +3291,7 @@ struct linux_target_ops the_low_target =
>    x86_siginfo_fixup,
>    x86_linux_new_process,
>    x86_linux_new_thread,
> +  x86_linux_new_fork,
>    x86_linux_prepare_to_resume,
>    x86_linux_process_qsupported,
>    x86_supports_tracepoints,
> --
> 1.8.1.1
> 

^ permalink raw reply	[flat|nested] 13+ messages in thread

* RE: [pushed][PATCH 4/7] Arch-specific remote follow fork
  2015-05-14 10:25   ` Vidya Praveen
@ 2015-05-14 16:02     ` Breazeal, Don
  0 siblings, 0 replies; 13+ messages in thread
From: Breazeal, Don @ 2015-05-14 16:02 UTC (permalink / raw)
  To: Vidya Praveen; +Cc: gdb-patches

Thanks, I will take a look.  --Don

> -----Original Message-----
> From: Vidya Praveen [mailto:vidyapraveen@arm.com]
> Sent: Thursday, May 14, 2015 3:26 AM
> To: Breazeal, Don
> Cc: gdb-patches@sourceware.org
> Subject: Re: [pushed][PATCH 4/7] Arch-specific remote follow fork
> 
> Don,
> 
> There are several instances of xyz->private->arch_private where xyz is
> (struct process_info*). Assume it is a typo (should've been priv instead
> of private)?
> 
> I atleast see aarch64 build of this fail.
> 
> Regards
> VP.
> 
> 
> On Tue, May 12, 2015 at 06:28:12PM +0100, Don Breazeal wrote:
> > This is the version of the patch that I pushed.
> > Thanks
> > --Don
> >
> >
> > This patch implements the architecture-specific pieces of follow-fork
> > for remote and extended-remote Linux targets, which in the current
> > implementation copyies the parent's debug register state into the new
> > child's data structures.  This is required for x86, arm, aarch64, and
> > mips.
> >
> > This follows the native implementation as closely as possible by
> > implementing a new linux_target_ops function 'new_fork', which is
> > analogous to 'linux_nat_new_fork' in linux-nat.c.  In gdbserver, the
> > debug registers are stored in the process list, instead of an
> > architecture-specific list, so the function arguments are process_info
> > pointers instead of an lwp_info and a pid as in the native
> implementation.
> >
> > In the MIPS implementation the debug register mirror is stored
> > differently from x86, ARM, and aarch64, so instead of doing a simple
> > structure assignment I had to clone the list of watchpoint structures.
> >
> > Tested using gdb.threads/watchpoint-fork.exp on x86, and ran manual
> > tests on a MIPS board and an ARM board.  Aarch64 hasn't been tested.
> >
> > gdb/gdbserver/ChangeLog:
> >
> >         * linux-aarch64-low.c (aarch64_linux_new_fork): New function.
> >         (the_low_target) <new_fork>: Initialize new member.
> >         * linux-arm-low.c (arm_new_fork): New function.
> >         (the_low_target) <new_fork>: Initialize new member.
> >         * linux-low.c (handle_extended_wait): Call new target function
> >         new_fork.
> >         * linux-low.h (struct linux_target_ops) <new_fork>: New
> member.
> >         * linux-mips-low.c (mips_add_watchpoint): New function
> >         extracted from mips_insert_point.
> >         (the_low_target) <new_fork>: Initialize new member.
> >         (mips_linux_new_fork): New function.
> >         (mips_insert_point): Call mips_add_watchpoint.
> >         * linux-x86-low.c (x86_linux_new_fork): New function.
> >         (the_low_target) <new_fork>: Initialize new member.
> > ---
> >  gdb/gdbserver/ChangeLog           | 17 +++++++++
> >  gdb/gdbserver/linux-aarch64-low.c | 28 +++++++++++++++
> >  gdb/gdbserver/linux-arm-low.c     | 42 ++++++++++++++++++++++
> >  gdb/gdbserver/linux-low.c         |  4 +++
> >  gdb/gdbserver/linux-low.h         |  3 ++
> >  gdb/gdbserver/linux-mips-low.c    | 76
> ++++++++++++++++++++++++++++++++-------
> >  gdb/gdbserver/linux-x86-low.c     | 29 +++++++++++++++
> >  7 files changed, 187 insertions(+), 12 deletions(-)
> >
> > diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index
> > 0ef695c..0bdcdf3 100644
> > --- a/gdb/gdbserver/ChangeLog
> > +++ b/gdb/gdbserver/ChangeLog
> > @@ -1,5 +1,22 @@
> >  2015-05-12  Don Breazeal  <donb@codesourcery.com>
> >
> > +       * linux-aarch64-low.c (aarch64_linux_new_fork): New function.
> > +       (the_low_target) <new_fork>: Initialize new member.
> > +       * linux-arm-low.c (arm_new_fork): New function.
> > +       (the_low_target) <new_fork>: Initialize new member.
> > +       * linux-low.c (handle_extended_wait): Call new target function
> > +       new_fork.
> > +       * linux-low.h (struct linux_target_ops) <new_fork>: New
> member.
> > +       * linux-mips-low.c (mips_add_watchpoint): New function
> > +       extracted from mips_insert_point.
> > +       (the_low_target) <new_fork>: Initialize new member.
> > +       (mips_linux_new_fork): New function.
> > +       (mips_insert_point): Call mips_add_watchpoint.
> > +       * linux-x86-low.c (x86_linux_new_fork): New function.
> > +       (the_low_target) <new_fork>: Initialize new member.
> > +
> > +2015-05-12  Don Breazeal  <donb@codesourcery.com>
> > +
> >         * linux-low.c (handle_extended_wait): Implement return value,
> >         rename argument 'event_child' to 'event_lwp', handle
> >         PTRACE_EVENT_FORK, call internal_error for unrecognized event.
> > diff --git a/gdb/gdbserver/linux-aarch64-low.c
> > b/gdb/gdbserver/linux-aarch64-low.c
> > index d44175e..7e6e9ac 100644
> > --- a/gdb/gdbserver/linux-aarch64-low.c
> > +++ b/gdb/gdbserver/linux-aarch64-low.c
> > @@ -1135,6 +1135,33 @@ aarch64_linux_new_thread (struct lwp_info *lwp)
> >    lwp->arch_private = info;
> >  }
> >
> > +static void
> > +aarch64_linux_new_fork (struct process_info *parent,
> > +                       struct process_info *child) {
> > +  /* These are allocated by linux_add_process.  */
> > +  gdb_assert (parent->private != NULL
> > +             && parent->private->arch_private != NULL);
> > +  gdb_assert (child->private != NULL
> > +             && child->private->arch_private != NULL);
> > +
> > +  /* Linux kernel before 2.6.33 commit
> > +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> > +     will inherit hardware debug registers from parent
> > +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> > +     zeroed debug registers.
> > +
> > +     GDB core assumes the child inherits the watchpoints/hw
> > +     breakpoints of the parent, and will remove them all from the
> > +     forked off process.  Copy the debug registers mirrors into the
> > +     new process so that all breakpoints and watchpoints can be
> > +     removed together.  The debug registers mirror will become zeroed
> > +     in the end before detaching the forked off process, thus making
> > +     this compatible with older Linux kernels too.  */
> > +
> > +  *child->private->arch_private = *parent->private->arch_private; }
> > +
> >  /* Called when resuming a thread.
> >     If the debug regs have changed, update the thread's copies.  */
> >
> > @@ -1299,6 +1326,7 @@ struct linux_target_ops the_low_target =
> >    NULL,
> >    aarch64_linux_new_process,
> >    aarch64_linux_new_thread,
> > +  aarch64_linux_new_fork,
> >    aarch64_linux_prepare_to_resume,
> >  };
> >
> > diff --git a/gdb/gdbserver/linux-arm-low.c
> > b/gdb/gdbserver/linux-arm-low.c index d408dcd..3420dea 100644
> > --- a/gdb/gdbserver/linux-arm-low.c
> > +++ b/gdb/gdbserver/linux-arm-low.c
> > @@ -717,6 +717,47 @@ arm_new_thread (struct lwp_info *lwp)
> >    lwp->arch_private = info;
> >  }
> >
> > +static void
> > +arm_new_fork (struct process_info *parent, struct process_info
> > +*child) {
> > +  struct arch_process_info *parent_proc_info =
> > +parent->private->arch_private;
> > +  struct arch_process_info *child_proc_info =
> > +child->private->arch_private;
> > +  struct lwp_info *child_lwp;
> > +  struct arch_lwp_info *child_lwp_info;
> > +  int i;
> > +
> > +  /* These are allocated by linux_add_process.  */  gdb_assert
> > + (parent->private != NULL
> > +             && parent->private->arch_private != NULL);  gdb_assert
> > + (child->private != NULL
> > +             && child->private->arch_private != NULL);
> > +
> > +  /* Linux kernel before 2.6.33 commit
> > +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> > +     will inherit hardware debug registers from parent
> > +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> > +     zeroed debug registers.
> > +
> > +     GDB core assumes the child inherits the watchpoints/hw
> > +     breakpoints of the parent, and will remove them all from the
> > +     forked off process.  Copy the debug registers mirrors into the
> > +     new process so that all breakpoints and watchpoints can be
> > +     removed together.  The debug registers mirror will become zeroed
> > +     in the end before detaching the forked off process, thus making
> > +     this compatible with older Linux kernels too.  */
> > +
> > +  *child_proc_info = *parent_proc_info;
> > +
> > +  /* Mark all the hardware breakpoints and watchpoints as changed to
> > +     make sure that the registers will be updated.  */
> > +  child_lwp = find_lwp_pid (ptid_of (child));
> > +  child_lwp_info = child_lwp->arch_private;
> > +  for (i = 0; i < MAX_BPTS; i++)
> > +    child_lwp_info->bpts_changed[i] = 1;
> > +  for (i = 0; i < MAX_WPTS; i++)
> > +    child_lwp_info->wpts_changed[i] = 1; }
> > +
> >  /* Called when resuming a thread.
> >     If the debug regs have changed, update the thread's copies.  */
> > static void @@ -920,6 +961,7 @@ struct linux_target_ops the_low_target
> > = {
> >    NULL, /* siginfo_fixup */
> >    arm_new_process,
> >    arm_new_thread,
> > +  arm_new_fork,
> >    arm_prepare_to_resume,
> >  };
> >
> > diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
> > index b280c17..d9053ad 100644
> > --- a/gdb/gdbserver/linux-low.c
> > +++ b/gdb/gdbserver/linux-low.c
> > @@ -489,6 +489,10 @@ handle_extended_wait (struct lwp_info *event_lwp,
> int wstat)
> >           child_proc->tdesc = tdesc;
> >           child_lwp->must_set_ptrace_flags = 1;
> >
> > +         /* Clone arch-specific process data.  */
> > +         if (the_low_target.new_fork != NULL)
> > +           the_low_target.new_fork (parent_proc, child_proc);
> > +
> >           /* Save fork info in the parent thread.  */
> >           event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED;
> >           event_lwp->waitstatus.value.related_pid = ptid; diff --git
> > a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h index
> > 41067d6..3300da9 100644
> > --- a/gdb/gdbserver/linux-low.h
> > +++ b/gdb/gdbserver/linux-low.h
> > @@ -187,6 +187,9 @@ struct linux_target_ops
> >       allocate it here.  */
> >    void (*new_thread) (struct lwp_info *);
> >
> > +  /* Hook to call, if any, when a new fork is attached.  */  void
> > + (*new_fork) (struct process_info *parent, struct process_info
> > + *child);
> > +
> >    /* Hook to call prior to resuming a thread.  */
> >    void (*prepare_to_resume) (struct lwp_info *);
> >
> > diff --git a/gdb/gdbserver/linux-mips-low.c
> > b/gdb/gdbserver/linux-mips-low.c index 7988d07..4601ad0 100644
> > --- a/gdb/gdbserver/linux-mips-low.c
> > +++ b/gdb/gdbserver/linux-mips-low.c
> > @@ -344,6 +344,68 @@ mips_linux_new_thread (struct lwp_info *lwp)
> >    lwp->arch_private = info;
> >  }
> >
> > +/* Create a new mips_watchpoint and add it to the list.  */
> > +
> > +static void
> > +mips_add_watchpoint (struct arch_process_info *private, CORE_ADDR
> addr,
> > +                    int len, int watch_type) {
> > +  struct mips_watchpoint *new_watch;
> > +  struct mips_watchpoint **pw;
> > +
> > +  new_watch = xmalloc (sizeof (struct mips_watchpoint));
> > + new_watch->addr = addr;  new_watch->len = len;  new_watch->type =
> > + watch_type;  new_watch->next = NULL;
> > +
> > +  pw = &private->current_watches;
> > +  while (*pw != NULL)
> > +    pw = &(*pw)->next;
> > +  *pw = new_watch;
> > +}
> > +
> > +/* Hook to call when a new fork is attached.  */
> > +
> > +static void
> > +mips_linux_new_fork (struct process_info *parent,
> > +                       struct process_info *child) {
> > +  struct arch_process_info *parent_private;
> > +  struct arch_process_info *child_private;
> > +  struct mips_watchpoint *wp;
> > +
> > +  /* These are allocated by linux_add_process.  */  gdb_assert
> > + (parent->private != NULL
> > +             && parent->private->arch_private != NULL);  gdb_assert
> > + (child->private != NULL
> > +             && child->private->arch_private != NULL);
> > +
> > +  /* Linux kernel before 2.6.33 commit
> > +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> > +     will inherit hardware debug registers from parent
> > +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> > +     zeroed debug registers.
> > +
> > +     GDB core assumes the child inherits the watchpoints/hw
> > +     breakpoints of the parent, and will remove them all from the
> > +     forked off process.  Copy the debug registers mirrors into the
> > +     new process so that all breakpoints and watchpoints can be
> > +     removed together.  The debug registers mirror will become zeroed
> > +     in the end before detaching the forked off process, thus making
> > +     this compatible with older Linux kernels too.  */
> > +
> > +  parent_private = parent->private->arch_private;  child_private =
> > + child->private->arch_private;
> > +
> > +  child_private->watch_readback_valid =
> > + parent_private->watch_readback_valid;
> > +  child_private->watch_readback = parent_private->watch_readback;
> > +
> > +  for (wp = parent_private->current_watches; wp != NULL; wp = wp-
> >next)
> > +    mips_add_watchpoint (child_private, wp->addr, wp->len, wp->type);
> > +
> > +  child_private->watch_mirror = parent_private->watch_mirror; }
> >  /* This is the implementation of linux_target_ops method
> >     prepare_to_resume.  If the watch regs have changed, update the
> >     thread's copies.  */
> > @@ -397,8 +459,6 @@ mips_insert_point (enum raw_bkpt_type type,
> CORE_ADDR addr,
> >    struct process_info *proc = current_process ();
> >    struct arch_process_info *priv = proc->priv->arch_private;
> >    struct pt_watch_regs regs;
> > -  struct mips_watchpoint *new_watch;
> > -  struct mips_watchpoint **pw;
> >    int pid;
> >    long lwpid;
> >    enum target_hw_bp_type watch_type;
> > @@ -425,16 +485,7 @@ mips_insert_point (enum raw_bkpt_type type,
> CORE_ADDR addr,
> >      return -1;
> >
> >    /* It fit.  Stick it on the end of the list.  */
> > -  new_watch = xmalloc (sizeof (struct mips_watchpoint));
> > -  new_watch->addr = addr;
> > -  new_watch->len = len;
> > -  new_watch->type = watch_type;
> > -  new_watch->next = NULL;
> > -
> > -  pw = &priv->current_watches;
> > -  while (*pw != NULL)
> > -    pw = &(*pw)->next;
> > -  *pw = new_watch;
> > +  mips_add_watchpoint (priv, addr, len, watch_type);
> >
> >    priv->watch_mirror = regs;
> >
> > @@ -845,6 +896,7 @@ struct linux_target_ops the_low_target = {
> >    NULL, /* siginfo_fixup */
> >    mips_linux_new_process,
> >    mips_linux_new_thread,
> > +  mips_linux_new_fork,
> >    mips_linux_prepare_to_resume
> >  };
> >
> > diff --git a/gdb/gdbserver/linux-x86-low.c
> > b/gdb/gdbserver/linux-x86-low.c index 763df08..4aef7b7 100644
> > --- a/gdb/gdbserver/linux-x86-low.c
> > +++ b/gdb/gdbserver/linux-x86-low.c
> > @@ -634,6 +634,34 @@ x86_linux_new_process (void)
> >    return info;
> >  }
> >
> > +/* Target routine for linux_new_fork.  */
> > +
> > +static void
> > +x86_linux_new_fork (struct process_info *parent, struct process_info
> > +*child) {
> > +  /* These are allocated by linux_add_process.  */
> > +  gdb_assert (parent->priv != NULL
> > +             && parent->priv->arch_private != NULL);
> > +  gdb_assert (child->priv != NULL
> > +             && child->priv->arch_private != NULL);
> > +
> > +  /* Linux kernel before 2.6.33 commit
> > +     72f674d203cd230426437cdcf7dd6f681dad8b0d
> > +     will inherit hardware debug registers from parent
> > +     on fork/vfork/clone.  Newer Linux kernels create such tasks with
> > +     zeroed debug registers.
> > +
> > +     GDB core assumes the child inherits the watchpoints/hw
> > +     breakpoints of the parent, and will remove them all from the
> > +     forked off process.  Copy the debug registers mirrors into the
> > +     new process so that all breakpoints and watchpoints can be
> > +     removed together.  The debug registers mirror will become zeroed
> > +     in the end before detaching the forked off process, thus making
> > +     this compatible with older Linux kernels too.  */
> > +
> > +  *child->priv->arch_private = *parent->priv->arch_private; }
> > +
> >  /* See nat/x86-dregs.h.  */
> >
> >  struct x86_debug_reg_state *
> > @@ -3263,6 +3291,7 @@ struct linux_target_ops the_low_target =
> >    x86_siginfo_fixup,
> >    x86_linux_new_process,
> >    x86_linux_new_thread,
> > +  x86_linux_new_fork,
> >    x86_linux_prepare_to_resume,
> >    x86_linux_process_qsupported,
> >    x86_supports_tracepoints,
> > --
> > 1.8.1.1
> >

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [pushed][PATCH 6/7] Extended-remote fork catch
  2015-05-12 17:29 ` [pushed][PATCH 6/7] Extended-remote fork catch Don Breazeal
@ 2015-05-14 22:11   ` Sergio Durigan Junior
  2015-05-14 23:26     ` Don Breazeal
  0 siblings, 1 reply; 13+ messages in thread
From: Sergio Durigan Junior @ 2015-05-14 22:11 UTC (permalink / raw)
  To: Don Breazeal; +Cc: gdb-patches

On Tuesday, May 12 2015, Don Breazeal wrote:

> This is the version of the patch that I pushed.
> Thanks
> --Don

Hi Don,

I see a bunch of failures introduced by your patches on our BuildBot.
For example, for this specific patch, I see:

  <https://sourceware.org/ml/gdb-testers/2015-q2/msg04109.html>

This is on Debian, but I also see the failures on Fedora 21:

  <https://sourceware.org/ml/gdb-testers/2015-q2/msg04127.html>

Are they expected?

-- 
Sergio
GPG key ID: 237A 54B1 0287 28BF 00EF  31F4 D0EB 7628 65FC 5E36
Please send encrypted e-mail if possible
http://sergiodj.net/

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [pushed][PATCH 6/7] Extended-remote fork catch
  2015-05-14 22:11   ` Sergio Durigan Junior
@ 2015-05-14 23:26     ` Don Breazeal
  2015-05-14 23:41       ` Sergio Durigan Junior
  0 siblings, 1 reply; 13+ messages in thread
From: Don Breazeal @ 2015-05-14 23:26 UTC (permalink / raw)
  To: Sergio Durigan Junior, Breazeal, Don; +Cc: gdb-patches

On 5/14/2015 3:11 PM, Sergio Durigan Junior wrote:
> On Tuesday, May 12 2015, Don Breazeal wrote:
> 
>> This is the version of the patch that I pushed.
>> Thanks
>> --Don
> 
> Hi Don,
> 
> I see a bunch of failures introduced by your patches on our BuildBot.
> For example, for this specific patch, I see:
> 
>   <https://sourceware.org/ml/gdb-testers/2015-q2/msg04109.html>
> 
> This is on Debian, but I also see the failures on Fedora 21:
> 
>   <https://sourceware.org/ml/gdb-testers/2015-q2/msg04127.html>
> 
> Are they expected?
> 
Hi Sergio
The failures in gdb.base/foll-vfork.exp, gdb.base/multi-forks.exp, and
gdb.threads/fork-thread-pending.exp are not expected.

The failures in gdb.threads/interrupted-hand-call.exp and
gdb.gdb/python-selftest.exp are failures that I saw intermittently in my
testing, and was able to reproduce on the mainline, as discussed here:
https://sourceware.org/ml/gdb-patches/2015-05/msg00180.html

The failure in gdb.base/attach.exp I don't know...the log doesn't
provide any clues.  I'll have to reproduce it to understand it.

Disappointing.  I'll check out a clean sandbox and see if I can
reproduce any of these results.
--Don

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [pushed][PATCH 6/7] Extended-remote fork catch
  2015-05-14 23:26     ` Don Breazeal
@ 2015-05-14 23:41       ` Sergio Durigan Junior
  2015-05-28 22:22         ` Don Breazeal
  0 siblings, 1 reply; 13+ messages in thread
From: Sergio Durigan Junior @ 2015-05-14 23:41 UTC (permalink / raw)
  To: Don Breazeal; +Cc: Breazeal, Don, gdb-patches

On Thursday, May 14 2015, Don Breazeal wrote:

> The failures in gdb.base/foll-vfork.exp, gdb.base/multi-forks.exp, and
> gdb.threads/fork-thread-pending.exp are not expected.

Hey Dan,

Well, because the GDB testsuite still has tests that fail intermitently,
I was mostly talking about the failures on
gdb.threads/fork-thread-pending.exp and gdb.base/foll-vfork.exp.

> The failures in gdb.threads/interrupted-hand-call.exp and
> gdb.gdb/python-selftest.exp are failures that I saw intermittently in my
> testing, and was able to reproduce on the mainline, as discussed here:
> https://sourceware.org/ml/gdb-patches/2015-05/msg00180.html

Yeah, as Pedro already explained in this message, our testsuite is not
entirely clean.  But a "New FAIL", in general, means that a regression
has been introduced.

> The failure in gdb.base/attach.exp I don't know...the log doesn't
> provide any clues.  I'll have to reproduce it to understand it.

Oh, this one is racy.  But if you're interested in following this up,
you can get the logs here:

  <http://gdb-build.sergiodj.net/cgit>

You have to choose the repository with the same name as the builder you
saw the failure, and then, inside it, you can look for a git tag
containing the commit hash (from the upstream GDB repo) that triggered
the failure.  Or, if you have the message from gdb-testers, you can see
the direct link to the logs in the "Testsuite log (gdb.sum and gdb.log)
URL(s):" field.

> Disappointing.  I'll check out a clean sandbox and see if I can
> reproduce any of these results.

Thanks for looking into this.  As I said, I think the priority should be
the new failures on gdb.threads/fork-thread-pending.exp and
gdb.base/foll-vfork.exp.

Cheers,

-- 
Sergio
GPG key ID: 237A 54B1 0287 28BF 00EF  31F4 D0EB 7628 65FC 5E36
Please send encrypted e-mail if possible
http://sergiodj.net/

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [pushed][PATCH 6/7] Extended-remote fork catch
  2015-05-14 23:41       ` Sergio Durigan Junior
@ 2015-05-28 22:22         ` Don Breazeal
  0 siblings, 0 replies; 13+ messages in thread
From: Don Breazeal @ 2015-05-28 22:22 UTC (permalink / raw)
  To: Sergio Durigan Junior, Breazeal, Don; +Cc: gdb-patches

On 5/14/2015 4:40 PM, Sergio Durigan Junior wrote:
> On Thursday, May 14 2015, Don Breazeal wrote:
> 
>> The failures in gdb.base/foll-vfork.exp, gdb.base/multi-forks.exp, and
>> gdb.threads/fork-thread-pending.exp are not expected.
> 
> Hey Dan,
> 
> Well, because the GDB testsuite still has tests that fail intermitently,
> I was mostly talking about the failures on
> gdb.threads/fork-thread-pending.exp and gdb.base/foll-vfork.exp.
> 
>> The failures in gdb.threads/interrupted-hand-call.exp and
>> gdb.gdb/python-selftest.exp are failures that I saw intermittently in my
>> testing, and was able to reproduce on the mainline, as discussed here:
>> https://sourceware.org/ml/gdb-patches/2015-05/msg00180.html
> 
> Yeah, as Pedro already explained in this message, our testsuite is not
> entirely clean.  But a "New FAIL", in general, means that a regression
> has been introduced.
> 
>> The failure in gdb.base/attach.exp I don't know...the log doesn't
>> provide any clues.  I'll have to reproduce it to understand it.
> 
> Oh, this one is racy.  But if you're interested in following this up,
> you can get the logs here:
> 
>   <http://gdb-build.sergiodj.net/cgit>
> 
> You have to choose the repository with the same name as the builder you
> saw the failure, and then, inside it, you can look for a git tag
> containing the commit hash (from the upstream GDB repo) that triggered
> the failure.  Or, if you have the message from gdb-testers, you can see
> the direct link to the logs in the "Testsuite log (gdb.sum and gdb.log)
> URL(s):" field.
> 
>> Disappointing.  I'll check out a clean sandbox and see if I can
>> reproduce any of these results.
> 
> Thanks for looking into this.  As I said, I think the priority should be
> the new failures on gdb.threads/fork-thread-pending.exp and
> gdb.base/foll-vfork.exp.
> 
> Cheers,
> 
Hi Sergio,
Just to close the loop on this: the new failures that you reported in
gdb.threads/fork-thread-pending.exp and gdb.base/foll-vfork.exp should
have now been addressed by the following three patches:

https://sourceware.org/ml/gdb-patches/2015-05/msg00696.html
https://sourceware.org/ml/gdb-patches/2015-05/msg00697.html
https://sourceware.org/ml/gdb-patches/2015-05/msg00698.html

Thanks
--Don

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2015-05-28 22:22 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-05-12 17:28 [pushed][PATCH 1/7] Identify remote fork event support Don Breazeal
2015-05-12 17:28 ` [pushed][PATCH 3/7] Extended-remote Linux follow fork Don Breazeal
2015-05-12 17:28 ` [pushed][PATCH 2/7] Clone remote breakpoints Don Breazeal
2015-05-12 17:29 ` [pushed][PATCH 6/7] Extended-remote fork catch Don Breazeal
2015-05-14 22:11   ` Sergio Durigan Junior
2015-05-14 23:26     ` Don Breazeal
2015-05-14 23:41       ` Sergio Durigan Junior
2015-05-28 22:22         ` Don Breazeal
2015-05-12 17:29 ` [pushed][PATCH 5/7] Extended-remote follow vfork Don Breazeal
2015-05-12 17:29 ` [pushed][PATCH 7/7] Extended-remote fork event docs Don Breazeal
2015-05-12 17:29 ` [pushed][PATCH 4/7] Arch-specific remote follow fork Don Breazeal
2015-05-14 10:25   ` Vidya Praveen
2015-05-14 16:02     ` Breazeal, Don

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