Commit b223564f authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google) Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Replace unacceptable characters when generating event name 



Replace unacceptable characters with '_' when generating event name from
the probing function name.

This is not for a C program. For the a C program, it will continue to
remove suffixes.

Note that this language checking depends on the debuginfo. So without
the debuginfo, perf probe will always replaces unacceptable characters
with '_'.

For example.

  $ ./perf probe -x cro3 -D \"cro3::cmd::servo::run_show\"
  p:probe_cro3/cro3_cmd_servo_run_show /work/cro3/target/x86_64-unknown-linux-gnu/debug/cro3:0x197530

  $ ./perf probe -x /work/go/example/outyet/main -D 'main.(*Server).poll'
  p:probe_main/main_Server_poll /work/go/example/outyet/main:0x353040

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/173145728160.2747044.18089011235495186810.stgit@mhiramat.roam.corp.google.com


[ Removed some extra tabs in the new struct fields ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 690a052a

tools/perf/util/probe-event.c

+25 −7
Original line number Diff line number Diff line
@@ -2775,7 +2775,7 @@ int show_perf_probe_events(struct strfilter *filter) 


static int get_new_event_name(char *buf, size_t len, const char *base,

			      struct strlist *namelist, bool ret_event,

			      bool allow_suffix)

			      bool allow_suffix, bool not_C_symname)

{

	int i, ret;

	char *p, *nbase;
@@ -2786,10 +2786,24 @@ static int get_new_event_name(char *buf, size_t len, const char *base, 
	if (!nbase)

		return -ENOMEM;



	if (not_C_symname) {

		/* Replace non-alnum with '_' */

		char *s, *d;



		s = d = nbase;

		do {

			if (*s && !isalnum(*s)) {

				if (d != nbase && *(d - 1) != '_')

					*d++ = '_';

			} else

				*d++ = *s;

		} while (*s++);

	} else {

		/* Cut off the dot suffixes (e.g. .const, .isra) and version suffixes */

		p = strpbrk(nbase, ".@");

		if (p && p != nbase)

			*p = '\0';

	}



	/* Try no suffix number */

	ret = e_snprintf(buf, len, "%s%s", nbase, ret_event ? "__return" : "");
@@ -2884,6 +2898,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev, 
				       bool allow_suffix)

{

	const char *event, *group;

	bool not_C_symname = true;

	char buf[MAX_EVENT_NAME_LEN];

	int ret;
@@ -2898,8 +2913,10 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev, 
			(strncmp(pev->point.function, "0x", 2) != 0) &&

			!strisglob(pev->point.function))

			event = pev->point.function;

		else

		else {

			event = tev->point.realname;

			not_C_symname = !is_known_C_lang(tev->lang);

		}

	}

	if (pev->group && !pev->sdt)

		group = pev->group;
@@ -2916,7 +2933,8 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev, 


	/* Get an unused new event name */

	ret = get_new_event_name(buf, sizeof(buf), event, namelist,

				 tev->point.retprobe, allow_suffix);

				 tev->point.retprobe, allow_suffix,

				 not_C_symname);

	if (ret < 0)

		return ret;

tools/perf/util/probe-event.h

+1 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ struct probe_trace_event { 
	char				*group;	/* Group name */

	struct probe_trace_point	point;	/* Trace point */

	int				nargs;	/* Number of args */

	int				lang;	/* Dwarf language code */

	bool				uprobes;	/* uprobes only */

	struct probe_trace_arg		*args;	/* Arguments */

};

tools/perf/util/probe-finder.c

+15 −0
Original line number Diff line number Diff line
@@ -35,6 +35,19 @@ 
/* Kprobe tracer basic type is up to u64 */

#define MAX_BASIC_TYPE_BITS	64



bool is_known_C_lang(int lang)

{

	switch (lang) {

	case DW_LANG_C89:

	case DW_LANG_C:

	case DW_LANG_C99:

	case DW_LANG_C11:

		return true;

	default:

		return false;

	}

}



/*

 * Probe finder related functions

 */
@@ -1270,6 +1283,8 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf) 
		goto end;

	}



	tev->lang = dwarf_srclang(dwarf_diecu(sc_die, &pf->cu_die, NULL, NULL));



	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,

		 tev->point.offset);

tools/perf/util/probe-finder.h

+5 −0
Original line number Diff line number Diff line
@@ -26,6 +26,9 @@ static inline int is_c_varname(const char *name) 
#include "dwarf-aux.h"

#include "debuginfo.h"



/* Check the language code is known C */

bool is_known_C_lang(int lang);



/* Find probe_trace_events specified by perf_probe_event from debuginfo */

int debuginfo__find_trace_events(struct debuginfo *dbg,

				 struct perf_probe_event *pev,
@@ -103,6 +106,8 @@ struct line_finder { 
	int			found;

};



#else

#define is_known_C_lang(lang) (false)

#endif /* HAVE_LIBDW_SUPPORT */



#endif /*_PROBE_FINDER_H */