/*
* 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/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
/* Session management structure */
static struct {
char *vmlinux;
char *release;
int need_dwarf;
int nr_probe;
struct probe_point probes[MAX_PROBES];
char *events[MAX_PROBES];
} session;
#define semantic_error(msg ...) die("Semantic error :" msg)
static int parse_probepoint(const struct option *opt __used,
const char *str, int unset __used)
{
char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */
int argc, i;
char *arg, *ptr;
struct probe_point *pp = &session.probes[session.nr_probe];
char **event = &session.events[session.nr_probe];
int retp = 0;
if (!str) /* The end of probe points */
return 0;
debug("Probe-define(%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");
debug("argv[%d]=%s\n", argc, argv[argc - 1]);
}
} while (*str != '\0');
if (argc < 2)
semantic_error("Need event-name and probe-point at least.");
/* Parse the event name */
if (argv[0][0] == 'r')
retp = 1;
else if (argv[0][0] != 'p')
semantic_error("You must specify 'p'(kprobe) or"
" 'r'(kretprobe) first.");
/* TODO: check event name */
*event = argv[0];
/* Parse probe point */
arg = argv[1];
if (arg[0] == '@') {
/* Source Line */
arg++;
ptr = strchr(arg, ':');
if (!ptr || !isdigit(ptr[1]))
semantic_error("Line number is required.");
*ptr++ = '\0';
if (strlen(arg) == 0)
semantic_error("No file name.");
pp->file = strdup(arg);
pp->line = atoi(ptr);
if (!pp->file || !pp->line)
semantic_error("Failed to parse line.");
debug("file:%s line:%d\n", pp->file, pp->line);
} else {
/* Function name */
ptr = strchr(arg, '+');
if (ptr) {
if (!isdigit(ptr[1]))
semantic_error("Offset is required.");
*ptr++ = '\0';
pp->offset = atoi(ptr);
} else
ptr = arg;
ptr = strchr(ptr, '@');
if (ptr) {
*ptr++ = '\0';
pp->file = strdup(ptr);
}
pp->function = strdup(arg);
debug("symbol:%s file:%s offset:%d\n",
pp->function, pp->file, pp->offset);
}
free(argv[1]);
if (pp->file)
session.need_dwarf = 1;
/* Copy arguments */
pp->nr_args = argc - 2;
if (pp->nr_args > 0) {
pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
if (!pp->args)
die("malloc");
memcpy(pp->args, &argv[2], 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 (retp)
semantic_error("You can't specify local"
" variable for kretprobe");
session.need_dwarf = 1;
}
debug("%d arguments\n", pp->nr_args);
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) {
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) {
debug("Filename(%d,%s) is too long.\n", i, uts.release);
errno = E2BIG;
return -E2BIG;
}
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>] -P 'PROBEDEF' [-P 'PROBEDEF' ...]",
NULL
};
static const struct option options[] = {
#ifndef NO_LIBDWARF
OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
"vmlinux/module pathname"),
#endif
OPT_CALLBACK('P', "probe", NULL,
#ifdef NO_LIBDWARF
"p|r:[GRP/]NAME FUNC[+OFFS] [ARG ...]",
#else
"p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]",
#endif
"probe point definition, where\n"
"\t\tp:\tkprobe probe\n"
"\t\tr:\tkretprobe probe\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"
#ifdef NO_LIBDWARF
"\t\tARG:\tProbe argument (only \n"
#else
"\t\tSRC:\tSource code path\n"
"\t\tLINE:\tLine number\n"
"\t\tARG:\tProbe argument (local variable name or\n"
#endif
"\t\t\tkprobe-tracer argument format is supported.)\n",
parse_probepoint),
OPT_END()
};
static int write_new_event(int fd, const char *buf)
{
int ret;
printf("Adding new event: %s\n", buf);
ret = write(fd, buf, strlen(buf));
if (ret <= 0)
die("failed to create event.");
return ret;
}
#define MAX_CMDLEN 256
static int synthesize_probepoint(struct probe_point *pp)
{
char *buf;
int i, len, ret;
pp->probes[0] = buf = (char *)calloc(MAX_CMDLEN, sizeof(char));
if (!buf)
die("calloc");
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);
if (argc || session.nr_probe == 0)
usage_with_options(probe_usage, options);
#ifdef NO_LIBDWARF
if (session.need_dwarf)
semantic_error("Dwarf-analysis is not supported");
#endif
/* Synthesize probes without dwarf */
for (j = 0; j < session.nr_probe; j++) {
#ifndef NO_LIBDWARF
if (session.events[j][0] != 'r') {
session.need_dwarf = 1;
continue;
}
#endif
ret = synthesize_probepoint(&session.probes[j]);
if (ret == -E2BIG)
semantic_error("probe point is too long.");
else if (ret < 0)
die("snprintf");
}
#ifndef NO_LIBDWARF
if (!session.need_dwarf)
goto setup_probes;
if (session.vmlinux)
fd = open(session.vmlinux, O_RDONLY);
else
fd = open_default_vmlinux();
if (fd < 0)
die("vmlinux/module file open");
/* 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)
die("No probe point found.\n");
debug("probe event %s found\n", session.events[j]);
}
close(fd);
setup_probes:
#endif /* !NO_LIBDWARF */
/* Settng up probe points */
snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);
fd = open(buf, O_WRONLY, O_APPEND);
if (fd < 0)
die("kprobe_events open");
for (j = 0; j < session.nr_probe; j++) {
pp = &session.probes[j];
if (pp->found == 1) {
snprintf(buf, MAX_CMDLEN, "%s %s\n",
session.events[j], pp->probes[0]);
write_new_event(fd, buf);
} else
for (i = 0; i < pp->found; i++) {
snprintf(buf, MAX_CMDLEN, "%s%d %s\n",
session.events[j], i, pp->probes[i]);
write_new_event(fd, buf);
}
}
close(fd);
return 0;
}
