[RFC] [gdb/cli] Add maintenance ignore-probes

[RFC] [gdb/cli] Add maintenance ignore-probes

[Tom de Vries]

There's a command "disable probes", but SystemTap probes cannot be disabled.

Add a command "maintenance ignore-probes" that ignores probes during
get_probes, such that we can easily pretend to use a glibc without say,
the longjmp probe:
...
(gdb) maint ignore-probes libc longjmp$
(gdb) start ^M
Temporary breakpoint 1 at 0x4005bb: file longjmp.c, line 46.
Starting program: outputs/gdb.base/longjmp/longjmp ^M
Ignoring SystemTap probe libc longjmp in /lib64/libc.so.6.^M
Ignoring SystemTap probe libc longjmp in /lib64/libc.so.6.^M
Ignoring SystemTap probe libc longjmp in /lib64/libc.so.6.^M
^M
Breakpoint 1, main () at longjmp.c:46^M
46        volatile int i = 0;^M
(gdb)
...

Note that as with "disable probes", running "maint ignore-probes" without
arguments ignores all probes.

PR cli/27159
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27159
---
 gdb/probe.c      | 49 ++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/probe.h      |  5 +++++
 gdb/stap-probe.c |  7 +++++++
 3 files changed, 61 insertions(+)

diff --git a/gdb/probe.c b/gdb/probe.c
index ec8845219fa..631f35ecd1f 100644
--- a/gdb/probe.c
+++ b/gdb/probe.c
@@ -680,6 +680,45 @@ disable_probes_command (const char *arg, int from_tty)
     }
 }
 
+static bool ignore_probes_p = false;
+static gdb::optional<compiled_regex> ignore_obj_pat;
+static gdb::optional<compiled_regex> ignore_prov_pat;
+static gdb::optional<compiled_regex> ignore_probe_pat;
+
+/* See comments in probe.h.  */
+
+bool ignore_probe (const char *provider, const char *name,
+		   const char *objfile_name)
+{
+  return (ignore_probes_p
+	  && (!ignore_obj_pat
+	      || ignore_obj_pat->exec (objfile_name, 0, NULL, 0) == 0)
+	  && (!ignore_prov_pat
+	      || ignore_prov_pat->exec (provider, 0, NULL, 0) == 0)
+	  && (!ignore_probe_pat
+	      || ignore_probe_pat->exec (name, 0, NULL, 0) == 0));
+}
+
+/* Implementation of the `maintenance ignore-probes' command.  */
+
+static void
+ignore_probes_command (const char *arg, int from_tty)
+{
+  std::string ignore_provider, ignore_probe_name, ignore_objname;
+
+  parse_probe_linespec ((const char *) arg, &ignore_provider,
+			&ignore_probe_name, &ignore_objname);
+
+  ignore_prov_pat.emplace (ignore_provider.c_str (), REG_NOSUB,
+			   _("Invalid provider regexp"));
+  ignore_probe_pat.emplace (ignore_probe_name.c_str (), REG_NOSUB,
+			    _("Invalid probe regexp"));
+  ignore_obj_pat.emplace (ignore_objname.c_str (), REG_NOSUB,
+			  _("Invalid object file regexp"));
+
+  ignore_probes_p = true;
+}
+
 /* See comments in probe.h.  */
 
 struct value *
@@ -931,4 +970,14 @@ If you do not specify any argument then the command will disable\n\
 all defined probes."),
 	   &disablelist);
 
+  add_cmd ("ignore-probes", class_maintenance, ignore_probes_command, _("\
+Ignore probes.\n\
+Usage: ignore probes [PROVIDER [NAME [OBJECT]]]\n\
+Each argument is a regular expression, used to select probes.\n\
+PROVIDER matches probe provider names.\n\
+NAME matches the probe names.\n\
+OBJECT matches the executable or shared library name.\n\
+If you do not specify any argument then the command will ignore\n\
+all defined probes.  Only supported for SystemTap probes"),
+	   &maintenancelist);
 }
diff --git a/gdb/probe.h b/gdb/probe.h
index 598f43a238e..3637ea9cc10 100644
--- a/gdb/probe.h
+++ b/gdb/probe.h
@@ -304,4 +304,9 @@ extern struct cmd_list_element **info_probes_cmdlist_get (void);
 extern struct value *probe_safe_evaluate_at_pc (frame_info_ptr frame,
 						unsigned n);
 
+/* Return true if the PROVIDER/NAME probe from OBJFILE_NAME needs to be
+   ignored.  */
+
+bool ignore_probe (const char *provider, const char *name,
+		   const char *objfile_name);
 #endif /* !defined (PROBE_H) */
diff --git a/gdb/stap-probe.c b/gdb/stap-probe.c
index 6f91d87846a..f244d85bb3d 100644
--- a/gdb/stap-probe.c
+++ b/gdb/stap-probe.c
@@ -1619,6 +1619,13 @@ handle_stap_probe (struct objfile *objfile, struct sdt_note *el,
       return;
     }
 
+  if (ignore_probe (provider, name, objfile_name (objfile)))
+    {
+      gdb_printf (gdb_stdlog, _("Ignoring SystemTap probe %s %s in %s.\n"),
+		  provider, name, objfile_name (objfile));
+      return;
+    }
+
   stap_probe *ret = new stap_probe (std::string (name), std::string (provider),
 				    address, gdbarch, sem_addr, probe_args);
 

base-commit: 58c49b3efef1833762ba4725937f8625058607f4
-- 
2.35.3

Re: [RFC] [gdb/cli] Add maintenance ignore-probes

[Tom Tromey]

>>>>> "Tom" == Tom de Vries via Gdb-patches <gdb-patches@sourceware.org> writes:

Tom> There's a command "disable probes", but SystemTap probes cannot be disabled.
Tom> Add a command "maintenance ignore-probes" that ignores probes during
Tom> get_probes, such that we can easily pretend to use a glibc without say,
Tom> the longjmp probe:

The idea seems sound to me.

Tom> Note that as with "disable probes", running "maint ignore-probes" without
Tom> arguments ignores all probes.

I didn't know about "disable probes" but I see now it's a DTrace thing.

Tom> +/* Implementation of the `maintenance ignore-probes' command.  */
Tom> +
Tom> +static void
Tom> +ignore_probes_command (const char *arg, int from_tty)
Tom> +{
Tom> +  std::string ignore_provider, ignore_probe_name, ignore_objname;
Tom> +
Tom> +  parse_probe_linespec ((const char *) arg, &ignore_provider,
Tom> +			&ignore_probe_name, &ignore_objname);

The cast there isn't needed.  I'm going to remove the other casts like
this in a second.

Also, maybe if arg==nullptr, this could set ignore_probes_p = false?
That would give a way to undo the change.

Tom> +  add_cmd ("ignore-probes", class_maintenance, ignore_probes_command, _("\
Tom> +Ignore probes.\n\
Tom> +Usage: ignore probes [PROVIDER [NAME [OBJECT]]]\n\

Missing the "-" in "ignore-probes".

Tom> +all defined probes.  Only supported for SystemTap probes"),

Probably should end with a "."

Tom

Re: [RFC] [gdb/cli] Add maintenance ignore-probes

[Tom de Vries]

[-- Attachment #1: Type: text/plain, Size: 2026 bytes --]

On 12/13/22 16:58, Tom Tromey wrote:
>>>>>> "Tom" == Tom de Vries via Gdb-patches <gdb-patches@sourceware.org> writes:
> 
> Tom> There's a command "disable probes", but SystemTap probes cannot be disabled.
> Tom> Add a command "maintenance ignore-probes" that ignores probes during
> Tom> get_probes, such that we can easily pretend to use a glibc without say,
> Tom> the longjmp probe:
> 
> The idea seems sound to me.
> 
> Tom> Note that as with "disable probes", running "maint ignore-probes" without
> Tom> arguments ignores all probes.
> 
> I didn't know about "disable probes" but I see now it's a DTrace thing.
> 
> Tom> +/* Implementation of the `maintenance ignore-probes' command.  */
> Tom> +
> Tom> +static void
> Tom> +ignore_probes_command (const char *arg, int from_tty)
> Tom> +{
> Tom> +  std::string ignore_provider, ignore_probe_name, ignore_objname;
> Tom> +
> Tom> +  parse_probe_linespec ((const char *) arg, &ignore_provider,
> Tom> +			&ignore_probe_name, &ignore_objname);
> 
> The cast there isn't needed.  I'm going to remove the other casts like
> this in a second.
> 

Done.

> Also, maybe if arg==nullptr, this could set ignore_probes_p = false?
> That would give a way to undo the change.
> 

That functionality is sort of already available as "maint ignore-probes 
foobar foobar foobar", but agreed, having a reliable and concise way to 
do it is better.

I've added that functionality, but as "maint ignore-probes -reset", to 
not break the similarity in usage with "disable probes"
	
> Tom> +  add_cmd ("ignore-probes", class_maintenance, ignore_probes_command, _("\
> Tom> +Ignore probes.\n\
> Tom> +Usage: ignore probes [PROVIDER [NAME [OBJECT]]]\n\
> 
> Missing the "-" in "ignore-probes".
> 

As well as the "maintenance" prefix, both fixed.

> Tom> +all defined probes.  Only supported for SystemTap probes"),
> 
> Probably should end with a "."

Done.

I've also added a -verbose option.

If you're ok with the updates, I'll add the docs part and do a proper 
submission.

Thanks,
- Tom

[-- Attachment #2: 0001-gdb-cli-Add-maintenance-ignore-probes.patch --]
[-- Type: text/x-patch, Size: 5910 bytes --]

From 71b320a91722133d4b39ef4d7e53fcaedf75ecb7 Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Mon, 5 Dec 2022 14:45:42 +0100
Subject: [PATCH] [gdb/cli] Add maintenance ignore-probes

There's a command "disable probes", but SystemTap probes cannot be disabled.

Add a command "maintenance ignore-probes" that ignores probes during
get_probes, such that we can easily pretend to use a glibc without say,
the longjmp probe:
...
(gdb) maint ignore-probes -verbose libc ^longjmp$
ignore-probes filter has been set to:
PROVIDER: 'libc'
PROBE_NAME: '^longjmp$'
OBJNAME: ''
(gdb) start ^M
Temporary breakpoint 1 at 0x4005bb: file longjmp.c, line 46.
Starting program: outputs/gdb.base/longjmp/longjmp ^M
Ignoring SystemTap probe libc longjmp in /lib64/libc.so.6.^M
Ignoring SystemTap probe libc longjmp in /lib64/libc.so.6.^M
Ignoring SystemTap probe libc longjmp in /lib64/libc.so.6.^M
^M
Breakpoint 1, main () at longjmp.c:46^M
46        volatile int i = 0;^M
(gdb)
...

Note that as with "disable probes", running "maint ignore-probes" without
arguments ignores all probes.

The ignore-probes filter can be reset by using:
...
(gdb) maint ignore-probes -reset
ignore-probes filter has been reset
...

For now, the command is only supported for SystemTap probes.

PR cli/27159
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27159
---
 gdb/probe.c      | 85 ++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/probe.h      |  5 +++
 gdb/stap-probe.c |  3 ++
 3 files changed, 93 insertions(+)

diff --git a/gdb/probe.c b/gdb/probe.c
index 4193f9f936b..1863cd96b02 100644
--- a/gdb/probe.c
+++ b/gdb/probe.c
@@ -680,6 +680,79 @@ disable_probes_command (const char *arg, int from_tty)
     }
 }
 
+static bool ignore_probes_p = false;
+static bool ignore_probes_verbose_p = false;
+static gdb::optional<compiled_regex> ignore_obj_pat;
+static gdb::optional<compiled_regex> ignore_prov_pat;
+static gdb::optional<compiled_regex> ignore_probe_pat;
+
+/* See comments in probe.h.  */
+
+bool ignore_probe (const char *provider, const char *name,
+		   const char *objfile_name, const char *type)
+{
+  bool res
+    = (ignore_probes_p
+       && (!ignore_obj_pat
+	   || ignore_obj_pat->exec (objfile_name, 0, NULL, 0) == 0)
+       && (!ignore_prov_pat
+	   || ignore_prov_pat->exec (provider, 0, NULL, 0) == 0)
+       && (!ignore_probe_pat
+	   || ignore_probe_pat->exec (name, 0, NULL, 0) == 0));
+
+  if (res && ignore_probes_verbose_p)
+    gdb_printf (gdb_stdlog, _("Ignoring %s probe %s %s in %s.\n"),
+		type, provider, name, objfile_name);
+
+  return res;
+}
+
+/* Implementation of the `maintenance ignore-probes' command.  */
+
+static void
+ignore_probes_command (const char *arg, int from_tty)
+{
+  std::string ignore_provider, ignore_probe_name, ignore_objname;
+
+  if (arg != nullptr && strcmp (arg,  "-reset") == 0)
+    {
+      ignore_probes_p = false;
+      gdb_printf (gdb_stdout, _("ignore-probes filter has been reset\n"));
+      return;
+    }
+
+  {
+    const char *str = "-verbose";
+    size_t len = strlen (str);
+    if (arg != nullptr
+	&& strncmp (arg, str, len) == 0
+	&& (arg[len] == '\0' || arg[len] == ' '))
+      {
+	ignore_probes_verbose_p = true;
+	if (arg[len] == '\0')
+	arg = nullptr;
+      else
+	arg += (len + 1);
+      }
+  }
+
+  parse_probe_linespec (arg, &ignore_provider, &ignore_probe_name,
+			&ignore_objname);
+
+  ignore_prov_pat.emplace (ignore_provider.c_str (), REG_NOSUB,
+			   _("Invalid provider regexp"));
+  ignore_probe_pat.emplace (ignore_probe_name.c_str (), REG_NOSUB,
+			    _("Invalid probe regexp"));
+  ignore_obj_pat.emplace (ignore_objname.c_str (), REG_NOSUB,
+			  _("Invalid object file regexp"));
+
+  gdb_printf (gdb_stdout, _("ignore-probes filter has been set to:\n"));
+  gdb_printf (gdb_stdout, _("PROVIDER: '%s'\n"), ignore_provider.c_str ());
+  gdb_printf (gdb_stdout, _("PROBE_NAME: '%s'\n"), ignore_probe_name.c_str ());
+  gdb_printf (gdb_stdout, _("OBJNAME: '%s'\n"), ignore_objname.c_str ());
+  ignore_probes_p = true;
+}
+
 /* See comments in probe.h.  */
 
 struct value *
@@ -931,4 +1004,16 @@ If you do not specify any argument then the command will disable\n\
 all defined probes."),
 	   &disablelist);
 
+  add_cmd ("ignore-probes", class_maintenance, ignore_probes_command, _("\
+Ignore probes.\n\
+Usage: maintenance ignore-probes [PROVIDER [NAME [OBJECT]]]\n\
+       maintenance ignore-probes -reset\n\
+Each argument is a regular expression, used to select probes.\n\
+PROVIDER matches probe provider names.\n\
+NAME matches the probe names.\n\
+OBJECT matches the executable or shared library name.\n\
+If you do not specify any argument then the command will ignore\n\
+all defined probes.  To reset the ignore-probes filter, use the -reset form.\n\
+Only supported for SystemTap probes."),
+	   &maintenancelist);
 }
diff --git a/gdb/probe.h b/gdb/probe.h
index 598f43a238e..70fb71d6ae4 100644
--- a/gdb/probe.h
+++ b/gdb/probe.h
@@ -304,4 +304,9 @@ extern struct cmd_list_element **info_probes_cmdlist_get (void);
 extern struct value *probe_safe_evaluate_at_pc (frame_info_ptr frame,
 						unsigned n);
 
+/* Return true if the PROVIDER/NAME probe from OBJFILE_NAME needs to be
+   ignored.  */
+
+bool ignore_probe (const char *provider, const char *name,
+		   const char *objfile_name, const char *TYPE);
 #endif /* !defined (PROBE_H) */
diff --git a/gdb/stap-probe.c b/gdb/stap-probe.c
index 6f91d87846a..a8a60d85e59 100644
--- a/gdb/stap-probe.c
+++ b/gdb/stap-probe.c
@@ -1619,6 +1619,9 @@ handle_stap_probe (struct objfile *objfile, struct sdt_note *el,
       return;
     }
 
+  if (ignore_probe (provider, name, objfile_name (objfile), "SystemTap"))
+    return;
+
   stap_probe *ret = new stap_probe (std::string (name), std::string (provider),
 				    address, gdbarch, sem_addr, probe_args);
 

base-commit: ea6929aaac370daddf0999faa553231c8b806b20
-- 
2.35.3

Re: [RFC] [gdb/cli] Add maintenance ignore-probes

[Tom Tromey]

Tom> That functionality is sort of already available as "maint
Tom> ignore-probes foobar foobar foobar", but agreed, having a reliable and
Tom> concise way to do it is better.

Hah, I didn't think of that.

Tom> If you're ok with the updates, I'll add the docs part and do a proper
Tom> submission.

Seems fine to me.

Tom