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OpenCloudOS-Kernel/tools/perf/builtin-probe.c

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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"
/* 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
#define MAX_PROBE_ARGS 128
#define PERFPROBE_GROUP "probe"
/* Session management structure */
static struct {
char *vmlinux;
char *release;
int need_dwarf;
int nr_probe;
struct probe_point probes[MAX_PROBES];
} session;
#define semantic_error(msg ...) die("Semantic error :" msg)
/* Parse probe point. Return 1 if return probe */
static void parse_probe_point(char *arg, struct probe_point *pp)
{
char *ptr, *tmp;
char c, nc = 0;
/*
* <Syntax>
* perf probe SRC:LN
* perf probe FUNC[+OFFS|%return][@SRC]
*/
ptr = strpbrk(arg, ":+@%");
if (ptr) {
nc = *ptr;
*ptr++ = '\0';
}
/* Check arg is function or file and copy it */
if (strchr(arg, '.')) /* File */
pp->file = strdup(arg);
else /* Function */
pp->function = strdup(arg);
DIE_IF(pp->file == NULL && pp->function == NULL);
/* Parse other options */
while (ptr) {
arg = ptr;
c = nc;
ptr = strpbrk(arg, ":+@%");
if (ptr) {
nc = *ptr;
*ptr++ = '\0';
}
switch (c) {
case ':': /* Line number */
pp->line = strtoul(arg, &tmp, 0);
if (*tmp != '\0')
semantic_error("There is non-digit charactor"
" in line number.");
break;
case '+': /* Byte offset from a symbol */
pp->offset = strtoul(arg, &tmp, 0);
if (*tmp != '\0')
semantic_error("There is non-digit charactor"
" in offset.");
break;
case '@': /* File name */
if (pp->file)
semantic_error("SRC@SRC is not allowed.");
pp->file = strdup(arg);
DIE_IF(pp->file == NULL);
if (ptr)
semantic_error("@SRC must be the last "
"option.");
break;
case '%': /* Probe places */
if (strcmp(arg, "return") == 0) {
pp->retprobe = 1;
} else /* Others not supported yet */
semantic_error("%%%s is not supported.", arg);
break;
default:
DIE_IF("Program has a bug.");
break;
}
}
/* Exclusion check */
if (pp->line && pp->offset)
semantic_error("Offset can't be used with line number.");
if (!pp->line && pp->file && !pp->function)
semantic_error("File always requires line number.");
if (pp->offset && !pp->function)
semantic_error("Offset requires an entry function.");
if (pp->retprobe && !pp->function)
semantic_error("Return probe requires an entry function.");
if ((pp->offset || pp->line) && pp->retprobe)
semantic_error("Offset/Line can't be used with return probe.");
pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
}
/* Parse an event definition. Note that any error must die. */
static void parse_probe_event(const char *str)
{
char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */
int argc, i;
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)
semantic_error("Too many probes");
/* Separate arguments, similar to argv_split */
argc = 0;
do {
/* Skip separators */
while (isspace(*str))
str++;
/* Add an argument */
if (*str != '\0') {
const char *s = str;
/* Skip the argument */
while (!isspace(*str) && *str != '\0')
str++;
/* Duplicate the argument */
argv[argc] = strndup(s, str - s);
if (argv[argc] == NULL)
die("strndup");
if (++argc == MAX_PROBE_ARGS)
semantic_error("Too many arguments");
pr_debug("argv[%d]=%s\n", argc, argv[argc - 1]);
}
} while (*str != '\0');
if (!argc)
semantic_error("An empty argument.");
/* Parse probe point */
parse_probe_point(argv[0], pp);
free(argv[0]);
if (pp->file || pp->line)
session.need_dwarf = 1;
/* Copy arguments */
pp->nr_args = argc - 1;
if (pp->nr_args > 0) {
pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
if (!pp->args)
die("malloc");
memcpy(pp->args, &argv[1], sizeof(char *) * pp->nr_args);
}
/* Ensure return probe has no C argument */
for (i = 0; i < pp->nr_args; i++)
if (is_c_varname(pp->args[i])) {
if (pp->retprobe)
semantic_error("You can't specify local"
" variable for kretprobe");
session.need_dwarf = 1;
}
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 is supported.)\n",
opt_add_probe_event),
OPT_END()
};
static int write_new_event(int fd, const char *buf)
{
int ret;
ret = write(fd, buf, strlen(buf));
if (ret <= 0)
die("Failed to create event.");
else
printf("Added new event: %s\n", buf);
return ret;
}
#define MAX_CMDLEN 256
static int synthesize_probe_event(struct probe_point *pp)
{
char *buf;
int i, len, ret;
pp->probes[0] = buf = zalloc(MAX_CMDLEN);
if (!buf)
die("Failed to allocate memory by zalloc.");
ret = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
if (ret <= 0 || ret >= MAX_CMDLEN)
goto error;
len = ret;
for (i = 0; i < pp->nr_args; i++) {
ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s",
pp->args[i]);
if (ret <= 0 || ret >= MAX_CMDLEN - len)
goto error;
len += ret;
}
pp->found = 1;
return pp->found;
error:
free(pp->probes[0]);
if (ret > 0)
ret = -E2BIG;
return ret;
}
int cmd_probe(int argc, const char **argv, const char *prefix __used)
{
int i, j, fd, ret;
struct probe_point *pp;
char buf[MAX_CMDLEN];
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
semantic_error("Debuginfo-analysis is not supported");
#else /* !NO_LIBDWARF */
pr_info("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_probe_event(pp);
if (ret == -E2BIG)
semantic_error("probe point is too long.");
else if (ret < 0)
die("Failed to synthesize a probe point.");
}
/* Settng up probe points */
snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);
fd = open(buf, O_WRONLY, O_APPEND);
if (fd < 0) {
if (errno == ENOENT)
die("kprobe_events file does not exist - please rebuild with CONFIG_KPROBE_TRACER.");
else
die("Could not open kprobe_events file: %s",
strerror(errno));
}
for (j = 0; j < session.nr_probe; j++) {
pp = &session.probes[j];
if (pp->found == 1) {
snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n",
pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP,
pp->function, pp->offset, pp->probes[0]);
write_new_event(fd, buf);
} else
for (i = 0; i < pp->found; i++) {
snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n",
pp->retprobe ? 'r' : 'p',
PERFPROBE_GROUP,
pp->function, pp->offset, i,
pp->probes[0]);
write_new_event(fd, buf);
}
}
close(fd);
return 0;
}
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