blob: cd7fbda5e2a57460a32ef56a673ddb3729d59b43 [file] [log] [blame]
/*
* probe-event.c : perf-probe definition to kprobe_events format converter
*
* 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>
#include <stdarg.h>
#include <limits.h>
#undef _GNU_SOURCE
#include "event.h"
#include "string.h"
#include "strlist.h"
#include "debug.h"
#include "parse-events.h" /* For debugfs_path */
#include "probe-event.h"
#define MAX_CMDLEN 256
#define MAX_PROBE_ARGS 128
#define PERFPROBE_GROUP "probe"
#define semantic_error(msg ...) die("Semantic error :" msg)
/* If there is no space to write, returns -E2BIG. */
static int e_snprintf(char *str, size_t size, const char *format, ...)
{
int ret;
va_list ap;
va_start(ap, format);
ret = vsnprintf(str, size, format, ap);
va_end(ap);
if (ret >= (int)size)
ret = -E2BIG;
return ret;
}
/* Parse probepoint definition. */
static void parse_perf_probe_probepoint(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 perf-probe event definition */
int parse_perf_probe_event(const char *str, struct probe_point *pp)
{
char **argv;
int argc, i, need_dwarf = 0;
argv = argv_split(str, &argc);
if (!argv)
die("argv_split failed.");
if (argc > MAX_PROBE_ARGS + 1)
semantic_error("Too many arguments");
/* Parse probe point */
parse_perf_probe_probepoint(argv[0], pp);
if (pp->file || pp->line)
need_dwarf = 1;
/* Copy arguments and ensure return probe has no C argument */
pp->nr_args = argc - 1;
pp->args = zalloc(sizeof(char *) * pp->nr_args);
for (i = 0; i < pp->nr_args; i++) {
pp->args[i] = strdup(argv[i + 1]);
if (!pp->args[i])
die("Failed to copy argument.");
if (is_c_varname(pp->args[i])) {
if (pp->retprobe)
semantic_error("You can't specify local"
" variable for kretprobe");
need_dwarf = 1;
}
}
argv_free(argv);
return need_dwarf;
}
/* Parse kprobe_events event into struct probe_point */
void parse_trace_kprobe_event(const char *str, char **group, char **event,
struct probe_point *pp)
{
char pr;
char *p;
int ret, i, argc;
char **argv;
pr_debug("Parsing kprobe_events: %s\n", str);
argv = argv_split(str, &argc);
if (!argv)
die("argv_split failed.");
if (argc < 2)
semantic_error("Too less arguments.");
/* Scan event and group name. */
ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
&pr, (float *)(void *)group, (float *)(void *)event);
if (ret != 3)
semantic_error("Failed to parse event name: %s", argv[0]);
pr_debug("Group:%s Event:%s probe:%c\n", *group, *event, pr);
if (!pp)
goto end;
pp->retprobe = (pr == 'r');
/* Scan function name and offset */
ret = sscanf(argv[1], "%a[^+]+%d", (float *)(void *)&pp->function, &pp->offset);
if (ret == 1)
pp->offset = 0;
/* kprobe_events doesn't have this information */
pp->line = 0;
pp->file = NULL;
pp->nr_args = argc - 2;
pp->args = zalloc(sizeof(char *) * pp->nr_args);
for (i = 0; i < pp->nr_args; i++) {
p = strchr(argv[i + 2], '=');
if (p) /* We don't need which register is assigned. */
*p = '\0';
pp->args[i] = strdup(argv[i + 2]);
if (!pp->args[i])
die("Failed to copy argument.");
}
end:
argv_free(argv);
}
int synthesize_perf_probe_event(struct probe_point *pp)
{
char *buf;
char offs[64] = "", line[64] = "";
int i, len, ret;
pp->probes[0] = buf = zalloc(MAX_CMDLEN);
if (!buf)
die("Failed to allocate memory by zalloc.");
if (pp->offset) {
ret = e_snprintf(offs, 64, "+%d", pp->offset);
if (ret <= 0)
goto error;
}
if (pp->line) {
ret = e_snprintf(line, 64, ":%d", pp->line);
if (ret <= 0)
goto error;
}
if (pp->function)
ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function,
offs, pp->retprobe ? "%return" : "", line);
else
ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->file, line);
if (ret <= 0)
goto error;
len = ret;
for (i = 0; i < pp->nr_args; i++) {
ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
pp->args[i]);
if (ret <= 0)
goto error;
len += ret;
}
pp->found = 1;
return pp->found;
error:
free(pp->probes[0]);
return ret;
}
int synthesize_trace_kprobe_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 = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
if (ret <= 0)
goto error;
len = ret;
for (i = 0; i < pp->nr_args; i++) {
ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
pp->args[i]);
if (ret <= 0)
goto error;
len += ret;
}
pp->found = 1;
return pp->found;
error:
free(pp->probes[0]);
return ret;
}
static int open_kprobe_events(int flags, int mode)
{
char buf[PATH_MAX];
int ret;
ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path);
if (ret < 0)
die("Failed to make kprobe_events path.");
ret = open(buf, flags, mode);
if (ret < 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));
}
return ret;
}
/* Get raw string list of current kprobe_events */
static struct strlist *get_trace_kprobe_event_rawlist(int fd)
{
int ret, idx;
FILE *fp;
char buf[MAX_CMDLEN];
char *p;
struct strlist *sl;
sl = strlist__new(true, NULL);
fp = fdopen(dup(fd), "r");
while (!feof(fp)) {
p = fgets(buf, MAX_CMDLEN, fp);
if (!p)
break;
idx = strlen(p) - 1;
if (p[idx] == '\n')
p[idx] = '\0';
ret = strlist__add(sl, buf);
if (ret < 0)
die("strlist__add failed: %s", strerror(-ret));
}
fclose(fp);
return sl;
}
/* Free and zero clear probe_point */
static void clear_probe_point(struct probe_point *pp)
{
int i;
if (pp->function)
free(pp->function);
if (pp->file)
free(pp->file);
for (i = 0; i < pp->nr_args; i++)
free(pp->args[i]);
if (pp->args)
free(pp->args);
for (i = 0; i < pp->found; i++)
free(pp->probes[i]);
memset(pp, 0, sizeof(pp));
}
/* List up current perf-probe events */
void show_perf_probe_events(void)
{
unsigned int i;
int fd;
char *group, *event;
struct probe_point pp;
struct strlist *rawlist;
struct str_node *ent;
fd = open_kprobe_events(O_RDONLY, 0);
rawlist = get_trace_kprobe_event_rawlist(fd);
close(fd);
for (i = 0; i < strlist__nr_entries(rawlist); i++) {
ent = strlist__entry(rawlist, i);
parse_trace_kprobe_event(ent->s, &group, &event, &pp);
synthesize_perf_probe_event(&pp);
printf("[%s:%s]\t%s\n", group, event, pp.probes[0]);
free(group);
free(event);
clear_probe_point(&pp);
}
strlist__delete(rawlist);
}
/* Get current perf-probe event names */
static struct strlist *get_perf_event_names(int fd)
{
unsigned int i;
char *group, *event;
struct strlist *sl, *rawlist;
struct str_node *ent;
rawlist = get_trace_kprobe_event_rawlist(fd);
sl = strlist__new(false, NULL);
for (i = 0; i < strlist__nr_entries(rawlist); i++) {
ent = strlist__entry(rawlist, i);
parse_trace_kprobe_event(ent->s, &group, &event, NULL);
strlist__add(sl, event);
free(group);
}
strlist__delete(rawlist);
return sl;
}
static int write_trace_kprobe_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;
}
static void get_new_event_name(char *buf, size_t len, const char *base,
struct strlist *namelist)
{
int i, ret;
for (i = 0; i < MAX_EVENT_INDEX; i++) {
ret = e_snprintf(buf, len, "%s_%d", base, i);
if (ret < 0)
die("snprintf() failed: %s", strerror(-ret));
if (!strlist__has_entry(namelist, buf))
break;
}
if (i == MAX_EVENT_INDEX)
die("Too many events are on the same function.");
}
void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
{
int i, j, fd;
struct probe_point *pp;
char buf[MAX_CMDLEN];
char event[64];
struct strlist *namelist;
fd = open_kprobe_events(O_RDWR, O_APPEND);
/* Get current event names */
namelist = get_perf_event_names(fd);
for (j = 0; j < nr_probes; j++) {
pp = probes + j;
for (i = 0; i < pp->found; i++) {
/* Get an unused new event name */
get_new_event_name(event, 64, pp->function, namelist);
snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n",
pp->retprobe ? 'r' : 'p',
PERFPROBE_GROUP, event,
pp->probes[i]);
write_trace_kprobe_event(fd, buf);
/* Add added event name to namelist */
strlist__add(namelist, event);
}
}
close(fd);
}