* Re: [RFC] [gdb/cli] Add maintenance ignore-probes
2022-12-13 15:58 ` Tom Tromey
@ 2022-12-13 21:50 ` Tom de Vries
2022-12-13 23:39 ` Tom Tromey
0 siblings, 1 reply; 4+ messages in thread
From: Tom de Vries @ 2022-12-13 21:50 UTC (permalink / raw)
To: Tom Tromey, Tom de Vries via Gdb-patches
[-- 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
^ permalink raw reply [flat|nested] 4+ messages in thread