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/*
* builtin-probe.c
*
* Builtin probe command: Set up probe events by C expression
*
* Written by Masami Hiramatsu <mhiramat@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#define _GNU_SOURCE
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#undef _GNU_SOURCE
#include "perf.h"
#include "builtin.h"
#include "util/util.h"
#include "util/event.h"
#include "util/debug.h"
#include "util/parse-options.h"
#include "util/parse-events.h" /* For debugfs_path */
#include "util/probe-finder.h"
#include "util/probe-event.h"
/* Default vmlinux search paths */
#define NR_SEARCH_PATH 3
const char *default_search_path[NR_SEARCH_PATH] = {
"/lib/modules/%s/build/vmlinux", /* Custom build kernel */
"/usr/lib/debug/lib/modules/%s/vmlinux", /* Red Hat debuginfo */
"/boot/vmlinux-debug-%s", /* Ubuntu */
};
#define MAX_PATH_LEN 256
#define MAX_PROBES 128
/* Session management structure */
static struct {
char *vmlinux;
char *release;
int need_dwarf;
int nr_probe;
struct probe_point probes[MAX_PROBES];
} session;
/* Parse an event definition. Note that any error must die. */
static void parse_probe_event(const char *str)
{
struct probe_point *pp = &session.probes[session.nr_probe];
pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
if (++session.nr_probe == MAX_PROBES)
die("Too many probes (> %d) are specified.", MAX_PROBES);
/* Parse perf-probe event into probe_point */
session.need_dwarf = parse_perf_probe_event(str, pp);
pr_debug("%d arguments\n", pp->nr_args);
}
static int opt_add_probe_event(const struct option *opt __used,
const char *str, int unset __used)
{
if (str)
parse_probe_event(str);
return 0;
}
#ifndef NO_LIBDWARF
static int open_default_vmlinux(void)
{
struct utsname uts;
char fname[MAX_PATH_LEN];
int fd, ret, i;
ret = uname(&uts);
if (ret) {
pr_debug("uname() failed.\n");
return -errno;
}
session.release = uts.release;
for (i = 0; i < NR_SEARCH_PATH; i++) {
ret = snprintf(fname, MAX_PATH_LEN,
default_search_path[i], session.release);
if (ret >= MAX_PATH_LEN || ret < 0) {
pr_debug("Filename(%d,%s) is too long.\n", i,
uts.release);
errno = E2BIG;
return -E2BIG;
}
pr_debug("try to open %s\n", fname);
fd = open(fname, O_RDONLY);
if (fd >= 0)
break;
}
return fd;
}
#endif
static const char * const probe_usage[] = {
"perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
"perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
NULL
};
static const struct option options[] = {
OPT_BOOLEAN('v', "verbose", &verbose,
"be more verbose (show parsed arguments, etc)"),
#ifndef NO_LIBDWARF
OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
"vmlinux/module pathname"),
#endif
OPT_CALLBACK('a', "add", NULL,
#ifdef NO_LIBDWARF
"FUNC[+OFFS|%return] [ARG ...]",
#else
"FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
#endif
"probe point definition, where\n"
"\t\tGRP:\tGroup name (optional)\n"
"\t\tNAME:\tEvent name\n"
"\t\tFUNC:\tFunction name\n"
"\t\tOFFS:\tOffset from function entry (in byte)\n"
"\t\t%return:\tPut the probe at function return\n"
#ifdef NO_LIBDWARF
"\t\tARG:\tProbe argument (only \n"
#else
"\t\tSRC:\tSource code path\n"
"\t\tRLN:\tRelative line number from function entry.\n"
"\t\tALN:\tAbsolute line number in file.\n"
"\t\tARG:\tProbe argument (local variable name or\n"
#endif
"\t\t\tkprobe-tracer argument format.)\n",
opt_add_probe_event),
OPT_END()
};
int cmd_probe(int argc, const char **argv, const char *prefix __used)
{
int i, j, fd, ret;
struct probe_point *pp;
argc = parse_options(argc, argv, options, probe_usage,
PARSE_OPT_STOP_AT_NON_OPTION);
for (i = 0; i < argc; i++)
parse_probe_event(argv[i]);
if (session.nr_probe == 0)
usage_with_options(probe_usage, options);
if (session.need_dwarf)
#ifdef NO_LIBDWARF
die("Debuginfo-analysis is not supported");
#else /* !NO_LIBDWARF */
pr_debug("Some probes require debuginfo.\n");
if (session.vmlinux)
fd = open(session.vmlinux, O_RDONLY);
else
fd = open_default_vmlinux();
if (fd < 0) {
if (session.need_dwarf)
die("Could not open vmlinux/module file.");
pr_warning("Could not open vmlinux/module file."
" Try to use symbols.\n");
goto end_dwarf;
}
/* Searching probe points */
for (j = 0; j < session.nr_probe; j++) {
pp = &session.probes[j];
if (pp->found)
continue;
lseek(fd, SEEK_SET, 0);
ret = find_probepoint(fd, pp);
if (ret < 0) {
if (session.need_dwarf)
die("Could not analyze debuginfo.");
pr_warning("An error occurred in debuginfo analysis. Try to use symbols.\n");
break;
}
if (ret == 0) /* No error but failed to find probe point. */
die("No probe point found.");
}
close(fd);
end_dwarf:
#endif /* !NO_LIBDWARF */
/* Synthesize probes without dwarf */
for (j = 0; j < session.nr_probe; j++) {
pp = &session.probes[j];
if (pp->found) /* This probe is already found. */
continue;
ret = synthesize_trace_kprobe_event(pp);
if (ret == -E2BIG)
die("probe point definition becomes too long.");
else if (ret < 0)
die("Failed to synthesize a probe point.");
}
/* Settng up probe points */
add_trace_kprobe_events(session.probes, session.nr_probe);
return 0;
}
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