* [PATCH 2/3] Move fbsd_resume and related functions below fork following helper code.
2016-06-28 23:00 [PATCH 0/3] Fake VFORK_DONE events on FreeBSD John Baldwin
2016-06-28 23:00 ` [PATCH 1/3] Honor detach-on-fork " John Baldwin
@ 2016-06-28 23:00 ` John Baldwin
2016-06-28 23:00 ` [PATCH 3/3] Fake VFORK_DONE events when following only the parent after a vfork John Baldwin
2016-07-01 14:07 ` [PATCH 0/3] Fake VFORK_DONE events on FreeBSD Pedro Alves
3 siblings, 0 replies; 5+ messages in thread
From: John Baldwin @ 2016-06-28 23:00 UTC (permalink / raw)
To: gdb-patches
gdb/ChangeLog:
* fbsd-nat.c (super_resume): Move earlier next to "super_wait".
(resume_one_thread_cb): Move below fork following helper code.
(resume_all_threads_cb): Likewise.
(fbsd_resume): Likewise.
---
gdb/ChangeLog | 7 ++++
gdb/fbsd-nat.c | 127 ++++++++++++++++++++++++++++-----------------------------
2 files changed, 70 insertions(+), 64 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 1c90732..09b75a5 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
2016-06-24 John Baldwin <jhb@FreeBSD.org>
+ * fbsd-nat.c (super_resume): Move earlier next to "super_wait".
+ (resume_one_thread_cb): Move below fork following helper code.
+ (resume_all_threads_cb): Likewise.
+ (fbsd_resume): Likewise.
+
+2016-06-24 John Baldwin <jhb@FreeBSD.org>
+
* fbsd-nat.c (fbsd_follow_fork): Only detach child if
"detach_fork" is true.
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 0f375f5..4b2b41a 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -281,6 +281,10 @@ fbsd_xfer_partial (struct target_ops *ops, enum target_object object,
#ifdef PT_LWPINFO
static int debug_fbsd_lwp;
+static void (*super_resume) (struct target_ops *,
+ ptid_t,
+ int,
+ enum gdb_signal);
static ptid_t (*super_wait) (struct target_ops *,
ptid_t,
struct target_waitstatus *,
@@ -492,70 +496,6 @@ fbsd_update_thread_list (struct target_ops *ops)
#endif
}
-static void (*super_resume) (struct target_ops *,
- ptid_t,
- int,
- enum gdb_signal);
-
-static int
-resume_one_thread_cb (struct thread_info *tp, void *data)
-{
- ptid_t *ptid = (ptid_t *) data;
- int request;
-
- if (ptid_get_pid (tp->ptid) != ptid_get_pid (*ptid))
- return 0;
-
- if (ptid_get_lwp (tp->ptid) == ptid_get_lwp (*ptid))
- request = PT_RESUME;
- else
- request = PT_SUSPEND;
-
- if (ptrace (request, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
- perror_with_name (("ptrace"));
- return 0;
-}
-
-static int
-resume_all_threads_cb (struct thread_info *tp, void *data)
-{
- ptid_t *filter = (ptid_t *) data;
-
- if (!ptid_match (tp->ptid, *filter))
- return 0;
-
- if (ptrace (PT_RESUME, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
- perror_with_name (("ptrace"));
- return 0;
-}
-
-/* Implement the "to_resume" target_ops method. */
-
-static void
-fbsd_resume (struct target_ops *ops,
- ptid_t ptid, int step, enum gdb_signal signo)
-{
-
- if (debug_fbsd_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "FLWP: fbsd_resume for ptid (%d, %ld, %ld)\n",
- ptid_get_pid (ptid), ptid_get_lwp (ptid),
- ptid_get_tid (ptid));
- if (ptid_lwp_p (ptid))
- {
- /* If ptid is a specific LWP, suspend all other LWPs in the process. */
- iterate_over_threads (resume_one_thread_cb, &ptid);
- }
- else
- {
- /* If ptid is a wildcard, resume all matching threads (they won't run
- until the process is continued however). */
- iterate_over_threads (resume_all_threads_cb, &ptid);
- ptid = inferior_ptid;
- }
- super_resume (ops, ptid, step, signo);
-}
-
#ifdef TDP_RFPPWAIT
/*
To catch fork events, PT_FOLLOW_FORK is set on every traced process
@@ -638,6 +578,65 @@ fbsd_is_child_pending (pid_t pid)
}
#endif
+static int
+resume_one_thread_cb (struct thread_info *tp, void *data)
+{
+ ptid_t *ptid = (ptid_t *) data;
+ int request;
+
+ if (ptid_get_pid (tp->ptid) != ptid_get_pid (*ptid))
+ return 0;
+
+ if (ptid_get_lwp (tp->ptid) == ptid_get_lwp (*ptid))
+ request = PT_RESUME;
+ else
+ request = PT_SUSPEND;
+
+ if (ptrace (request, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
+ perror_with_name (("ptrace"));
+ return 0;
+}
+
+static int
+resume_all_threads_cb (struct thread_info *tp, void *data)
+{
+ ptid_t *filter = (ptid_t *) data;
+
+ if (!ptid_match (tp->ptid, *filter))
+ return 0;
+
+ if (ptrace (PT_RESUME, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
+ perror_with_name (("ptrace"));
+ return 0;
+}
+
+/* Implement the "to_resume" target_ops method. */
+
+static void
+fbsd_resume (struct target_ops *ops,
+ ptid_t ptid, int step, enum gdb_signal signo)
+{
+
+ if (debug_fbsd_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "FLWP: fbsd_resume for ptid (%d, %ld, %ld)\n",
+ ptid_get_pid (ptid), ptid_get_lwp (ptid),
+ ptid_get_tid (ptid));
+ if (ptid_lwp_p (ptid))
+ {
+ /* If ptid is a specific LWP, suspend all other LWPs in the process. */
+ iterate_over_threads (resume_one_thread_cb, &ptid);
+ }
+ else
+ {
+ /* If ptid is a wildcard, resume all matching threads (they won't run
+ until the process is continued however). */
+ iterate_over_threads (resume_all_threads_cb, &ptid);
+ ptid = inferior_ptid;
+ }
+ super_resume (ops, ptid, step, signo);
+}
+
/* Wait for the child specified by PTID to do something. Return the
process ID of the child, or MINUS_ONE_PTID in case of error; store
the status in *OURSTATUS. */
--
2.8.4
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/3] Honor detach-on-fork on FreeBSD.
2016-06-28 23:00 [PATCH 0/3] Fake VFORK_DONE events on FreeBSD John Baldwin
@ 2016-06-28 23:00 ` John Baldwin
2016-06-28 23:00 ` [PATCH 2/3] Move fbsd_resume and related functions below fork following helper code John Baldwin
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: John Baldwin @ 2016-06-28 23:00 UTC (permalink / raw)
To: gdb-patches
Only detach from the new child process in the follow fork callback
if detach_fork is true.
gdb/ChangeLog:
* fbsd-nat.c (fbsd_follow_fork): Only detach child if
"detach_fork" is true.x
---
gdb/ChangeLog | 5 +++++
gdb/fbsd-nat.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 22234be..1c90732 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
2016-06-24 John Baldwin <jhb@FreeBSD.org>
+ * fbsd-nat.c (fbsd_follow_fork): Only detach child if
+ "detach_fork" is true.
+
+2016-06-24 John Baldwin <jhb@FreeBSD.org>
+
* fbsd-tdep.c: Include "auxv.h".
(fbsd_print_auxv_entry): New function.
(fbsd_init_abi): Install gdbarch "print_auxv_entry" method.
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index dc65e29..0f375f5 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -792,7 +792,7 @@ static int
fbsd_follow_fork (struct target_ops *ops, int follow_child,
int detach_fork)
{
- if (!follow_child)
+ if (!follow_child && detach_fork)
{
struct thread_info *tp = inferior_thread ();
pid_t child_pid = ptid_get_pid (tp->pending_follow.value.related_pid);
--
2.8.4
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 0/3] Fake VFORK_DONE events on FreeBSD
@ 2016-06-28 23:00 John Baldwin
2016-06-28 23:00 ` [PATCH 1/3] Honor detach-on-fork " John Baldwin
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: John Baldwin @ 2016-06-28 23:00 UTC (permalink / raw)
To: gdb-patches
The FreeBSD native targets do not report a VFORK_DONE event at
all currently. FreeBSD's ptrace doesn't currently report an event
when the vfork parent resumes, so this fixes the native targets to
report a fake event after a sleep similar to the approach used on
Linux. While here I noticed that I botched the 'detach_fork' support
in the original fork tracing patches, so I fixed that as well.
I am working on adding a new ptrace event to report a real vfork
done event to FreeBSD. Once that is merged to FreeBSD I will post
a patch for gdb to use that when available instead.
John Baldwin (3):
Honor detach-on-fork on FreeBSD.
Move fbsd_resume and related functions below fork following helper
code.
Fake VFORK_DONE events when following only the parent after a vfork.
gdb/ChangeLog | 30 ++++++++
gdb/fbsd-nat.c | 239 +++++++++++++++++++++++++++++++++++++++------------------
2 files changed, 195 insertions(+), 74 deletions(-)
--
2.8.4
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 3/3] Fake VFORK_DONE events when following only the parent after a vfork.
2016-06-28 23:00 [PATCH 0/3] Fake VFORK_DONE events on FreeBSD John Baldwin
2016-06-28 23:00 ` [PATCH 1/3] Honor detach-on-fork " John Baldwin
2016-06-28 23:00 ` [PATCH 2/3] Move fbsd_resume and related functions below fork following helper code John Baldwin
@ 2016-06-28 23:00 ` John Baldwin
2016-07-01 14:07 ` [PATCH 0/3] Fake VFORK_DONE events on FreeBSD Pedro Alves
3 siblings, 0 replies; 5+ messages in thread
From: John Baldwin @ 2016-06-28 23:00 UTC (permalink / raw)
To: gdb-patches
FreeBSD does not currently report a ptrace event for a parent process
after it resumes due to the child exiting the shared memory region after
a vfork. Take the same approach used in linux-nat.c in this case of
sleeping for a while and then reporting a fake VFORK_DONE event.
gdb/ChangeLog:
* fbsd-nat.c (struct fbsd_fork_child_info): Rename to ...
(struct fbsd_fork_info): ... this.
(struct fbsd_fork_info) <child>: Rename to ...
(struct fbsd_fork_info) <ptid>: ... this.
(fbsd_pending_children): Update type.
(fbsd_remember_child): Update type and field name.
(fbsd_is_child_pending): Likewise.
(fbsd_pending_vfork_done): New variable.
(fbsd_is_vfork_done_pending): New function.
(fbsd_next_vfork_done): New function.
(fbsd_resume): Don't resume processes with a pending vfork done
event.
(fbsd_wait): Report pending vfork done events.
(fbsd_follow_fork): Delay and record a pending vfork done event
for a vfork parent when detaching the child.
---
gdb/ChangeLog | 18 ++++++++++
gdb/fbsd-nat.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 119 insertions(+), 9 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 09b75a5..0ea329a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,23 @@
2016-06-24 John Baldwin <jhb@FreeBSD.org>
+ * fbsd-nat.c (struct fbsd_fork_child_info): Rename to ...
+ (struct fbsd_fork_info): ... this.
+ (struct fbsd_fork_info) <child>: Rename to ...
+ (struct fbsd_fork_info) <ptid>: ... this.
+ (fbsd_pending_children): Update type.
+ (fbsd_remember_child): Update type and field name.
+ (fbsd_is_child_pending): Likewise.
+ (fbsd_pending_vfork_done): New variable.
+ (fbsd_is_vfork_done_pending): New function.
+ (fbsd_next_vfork_done): New function.
+ (fbsd_resume): Don't resume processes with a pending vfork done
+ event.
+ (fbsd_wait): Report pending vfork done events.
+ (fbsd_follow_fork): Delay and record a pending vfork done event
+ for a vfork parent when detaching the child.
+
+2016-06-24 John Baldwin <jhb@FreeBSD.org>
+
* fbsd-nat.c (super_resume): Move earlier next to "super_wait".
(resume_one_thread_cb): Move below fork following helper code.
(resume_all_threads_cb): Likewise.
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 4b2b41a..f1dc743 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -530,13 +530,13 @@ fbsd_update_thread_list (struct target_ops *ops)
sake. FreeBSD versions newer than 9.1 contain both fixes.
*/
-struct fbsd_fork_child_info
+struct fbsd_fork_info
{
- struct fbsd_fork_child_info *next;
- ptid_t child; /* Pid of new child. */
+ struct fbsd_fork_info *next;
+ ptid_t ptid;
};
-static struct fbsd_fork_child_info *fbsd_pending_children;
+static struct fbsd_fork_info *fbsd_pending_children;
/* Record a new child process event that is reported before the
corresponding fork event in the parent. */
@@ -544,9 +544,9 @@ static struct fbsd_fork_child_info *fbsd_pending_children;
static void
fbsd_remember_child (ptid_t pid)
{
- struct fbsd_fork_child_info *info = XCNEW (struct fbsd_fork_child_info);
+ struct fbsd_fork_info *info = XCNEW (struct fbsd_fork_info);
- info->child = pid;
+ info->ptid = pid;
info->next = fbsd_pending_children;
fbsd_pending_children = info;
}
@@ -557,25 +557,74 @@ fbsd_remember_child (ptid_t pid)
static ptid_t
fbsd_is_child_pending (pid_t pid)
{
- struct fbsd_fork_child_info *info, *prev;
+ struct fbsd_fork_info *info, *prev;
ptid_t ptid;
prev = NULL;
for (info = fbsd_pending_children; info; prev = info, info = info->next)
{
- if (ptid_get_pid (info->child) == pid)
+ if (ptid_get_pid (info->ptid) == pid)
{
if (prev == NULL)
fbsd_pending_children = info->next;
else
prev->next = info->next;
- ptid = info->child;
+ ptid = info->ptid;
xfree (info);
return ptid;
}
}
return null_ptid;
}
+
+static struct fbsd_fork_info *fbsd_pending_vfork_done;
+
+/* Record a pending vfork done event. */
+
+static void
+fbsd_add_vfork_done (ptid_t pid)
+{
+ struct fbsd_fork_info *info = XCNEW (struct fbsd_fork_info);
+
+ info->ptid = pid;
+ info->next = fbsd_pending_vfork_done;
+ fbsd_pending_vfork_done = info;
+}
+
+/* Check for a pending vfork done event for a specific PID. */
+
+static int
+fbsd_is_vfork_done_pending (pid_t pid)
+{
+ struct fbsd_fork_info *info;
+
+ for (info = fbsd_pending_vfork_done; info != NULL; info = info->next)
+ {
+ if (ptid_get_pid (info->ptid) == pid)
+ return 1;
+ }
+ return 0;
+}
+
+/* Check for a pending vfork done event. If one is found, remove it
+ from the list and return the PTID. */
+
+static ptid
+fbsd_next_vfork_done (void)
+{
+ struct fbsd_fork_info *info;
+ ptid_t ptid;
+
+ if (fbsd_pending_vfork_done != NULL)
+ {
+ info = fbsd_pending_vfork_done;
+ fbsd_pending_vfork_done = info->next;
+ ptid = info->ptid;
+ xfree (info);
+ return ptid;
+ }
+ return null_ptid;
+}
#endif
static int
@@ -616,6 +665,17 @@ static void
fbsd_resume (struct target_ops *ops,
ptid_t ptid, int step, enum gdb_signal signo)
{
+#ifdef TDP_RFPPWAIT
+ pid_t pid;
+
+ /* Don't PT_CONTINUE a process which has a pending vfork done event. */
+ if (ptid_equal (minus_one_ptid, ptid))
+ pid = ptid_get_pid (inferior_ptid);
+ else
+ pid = ptid_get_pid (ptid);
+ if (fbsd_is_vfork_done_pending (pid))
+ return;
+#endif
if (debug_fbsd_lwp)
fprintf_unfiltered (gdb_stdlog,
@@ -650,6 +710,12 @@ fbsd_wait (struct target_ops *ops,
while (1)
{
+ wptid = fbsd_next_vfork_done ();
+ if (!ptid_equal (wptid, null_ptid))
+ {
+ ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
+ return wptid;
+ }
wptid = super_wait (ops, ptid, ourstatus, target_options);
if (ourstatus->kind == TARGET_WAITKIND_STOPPED)
{
@@ -794,6 +860,7 @@ fbsd_follow_fork (struct target_ops *ops, int follow_child,
if (!follow_child && detach_fork)
{
struct thread_info *tp = inferior_thread ();
+ int has_vforked = tp->pending_follow.kind == TARGET_WAITKIND_VFORKED;
pid_t child_pid = ptid_get_pid (tp->pending_follow.value.related_pid);
/* Breakpoints have already been detached from the child by
@@ -801,6 +868,31 @@ fbsd_follow_fork (struct target_ops *ops, int follow_child,
if (ptrace (PT_DETACH, child_pid, (PTRACE_TYPE_ARG3)1, 0) == -1)
perror_with_name (("ptrace"));
+
+ if (has_vforked)
+ {
+ /* We can't insert breakpoints until the child process has
+ finished with the shared memory region. The parent
+ process doesn't wait for the child process to exit or
+ exec until after it has been resumed from the ptrace stop
+ to report the fork. Once it has been resumed it doesn't
+ stop again before returning to userland, so there is no
+ reliable way to wait on the parent.
+
+ We can't stay attached to the child to wait for an exec
+ or exit because it may invoke ptrace(PT_TRACE_ME)
+ (e.g. if the parent process is a debugger forking a new
+ child process).
+
+ Take the same approach used in linux-nat.c of just
+ sleeping and hoping the sleep is long enough. */
+
+ usleep (10000);
+
+ /* Schedule a fake VFORK_DONE event to report on the next
+ wait. */
+ fbsd_add_vfork_done (inferior_ptid);
+ }
}
return 0;
--
2.8.4
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 0/3] Fake VFORK_DONE events on FreeBSD
2016-06-28 23:00 [PATCH 0/3] Fake VFORK_DONE events on FreeBSD John Baldwin
` (2 preceding siblings ...)
2016-06-28 23:00 ` [PATCH 3/3] Fake VFORK_DONE events when following only the parent after a vfork John Baldwin
@ 2016-07-01 14:07 ` Pedro Alves
3 siblings, 0 replies; 5+ messages in thread
From: Pedro Alves @ 2016-07-01 14:07 UTC (permalink / raw)
To: John Baldwin, gdb-patches
On 06/29/2016 12:00 AM, John Baldwin wrote:
> The FreeBSD native targets do not report a VFORK_DONE event at
> all currently. FreeBSD's ptrace doesn't currently report an event
> when the vfork parent resumes, so this fixes the native targets to
> report a fake event after a sleep similar to the approach used on
> Linux. While here I noticed that I botched the 'detach_fork' support
> in the original fork tracing patches, so I fixed that as well.
>
> I am working on adding a new ptrace event to report a real vfork
> done event to FreeBSD. Once that is merged to FreeBSD I will post
> a patch for gdb to use that when available instead.
LGTM.
- There's a tiny typo in the commit log of patch 1: "true.x".
- I suggest removing the reference to linux-nat.c in the comment in
patch #3, because that workaround may be removed soon.
Thanks,
Pedro Alves
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-07-01 14:07 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2016-06-28 23:00 [PATCH 0/3] Fake VFORK_DONE events on FreeBSD John Baldwin
2016-06-28 23:00 ` [PATCH 1/3] Honor detach-on-fork " John Baldwin
2016-06-28 23:00 ` [PATCH 2/3] Move fbsd_resume and related functions below fork following helper code John Baldwin
2016-06-28 23:00 ` [PATCH 3/3] Fake VFORK_DONE events when following only the parent after a vfork John Baldwin
2016-07-01 14:07 ` [PATCH 0/3] Fake VFORK_DONE events on FreeBSD Pedro Alves
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