4 * Builtin probe command: Set up probe events by C expression
6 * Written by Masami Hiramatsu <mhiramat@redhat.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24 #include <sys/utsname.h>
25 #include <sys/types.h>
37 #include "util/util.h"
38 #include "util/event.h"
39 #include "util/debug.h"
40 #include "util/parse-options.h"
41 #include "util/parse-events.h" /* For debugfs_path */
42 #include "util/probe-finder.h"
44 /* Default vmlinux search paths */
45 #define NR_SEARCH_PATH 3
46 const char *default_search_path[NR_SEARCH_PATH] = {
47 "/lib/modules/%s/build/vmlinux", /* Custom build kernel */
48 "/usr/lib/debug/lib/modules/%s/vmlinux", /* Red Hat debuginfo */
49 "/boot/vmlinux-debug-%s", /* Ubuntu */
52 #define MAX_PATH_LEN 256
53 #define MAX_PROBES 128
54 #define MAX_PROBE_ARGS 128
55 #define PERFPROBE_GROUP "probe"
57 /* Session management structure */
63 struct probe_point probes[MAX_PROBES];
66 #define semantic_error(msg ...) die("Semantic error :" msg)
68 /* Parse probe point. Return 1 if return probe */
69 static void parse_probe_point(char *arg, struct probe_point *pp)
76 * perf probe FUNC[+OFFS|%return][@SRC]
79 ptr = strpbrk(arg, ":+@%");
85 /* Check arg is function or file and copy it */
86 if (strchr(arg, '.')) /* File */
87 pp->file = strdup(arg);
89 pp->function = strdup(arg);
90 DIE_IF(pp->file == NULL && pp->function == NULL);
92 /* Parse other options */
96 ptr = strpbrk(arg, ":+@%");
102 case ':': /* Line number */
103 pp->line = strtoul(arg, &tmp, 0);
105 semantic_error("There is non-digit charactor"
108 case '+': /* Byte offset from a symbol */
109 pp->offset = strtoul(arg, &tmp, 0);
111 semantic_error("There is non-digit charactor"
114 case '@': /* File name */
116 semantic_error("SRC@SRC is not allowed.");
117 pp->file = strdup(arg);
118 DIE_IF(pp->file == NULL);
120 semantic_error("@SRC must be the last "
123 case '%': /* Probe places */
124 if (strcmp(arg, "return") == 0) {
126 } else /* Others not supported yet */
127 semantic_error("%%%s is not supported.", arg);
130 DIE_IF("Program has a bug.");
135 /* Exclusion check */
136 if (pp->line && pp->offset)
137 semantic_error("Offset can't be used with line number.");
138 if (!pp->line && pp->file && !pp->function)
139 semantic_error("File always requires line number.");
140 if (pp->offset && !pp->function)
141 semantic_error("Offset requires an entry function.");
142 if (pp->retprobe && !pp->function)
143 semantic_error("Return probe requires an entry function.");
144 if ((pp->offset || pp->line) && pp->retprobe)
145 semantic_error("Offset/Line can't be used with return probe.");
147 pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
148 pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
151 /* Parse an event definition. Note that any error must die. */
152 static void parse_probe_event(const char *str)
154 char *argv[MAX_PROBE_ARGS + 1]; /* probe + args */
156 struct probe_point *pp = &session.probes[session.nr_probe];
158 pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
159 if (++session.nr_probe == MAX_PROBES)
160 semantic_error("Too many probes");
162 /* Separate arguments, similar to argv_split */
165 /* Skip separators */
166 while (isspace(*str))
169 /* Add an argument */
172 /* Check the limit number of arguments */
173 if (argc == MAX_PROBE_ARGS + 1)
174 semantic_error("Too many arguments");
176 /* Skip the argument */
177 while (!isspace(*str) && *str != '\0')
180 /* Duplicate the argument */
181 argv[argc] = strndup(s, str - s);
182 if (argv[argc] == NULL)
184 pr_debug("argv[%d]=%s\n", argc, argv[argc]);
188 } while (*str != '\0');
190 semantic_error("An empty argument.");
192 /* Parse probe point */
193 parse_probe_point(argv[0], pp);
195 if (pp->file || pp->line)
196 session.need_dwarf = 1;
199 pp->nr_args = argc - 1;
200 if (pp->nr_args > 0) {
201 pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
204 memcpy(pp->args, &argv[1], sizeof(char *) * pp->nr_args);
207 /* Ensure return probe has no C argument */
208 for (i = 0; i < pp->nr_args; i++)
209 if (is_c_varname(pp->args[i])) {
211 semantic_error("You can't specify local"
212 " variable for kretprobe");
213 session.need_dwarf = 1;
216 pr_debug("%d arguments\n", pp->nr_args);
219 static int opt_add_probe_event(const struct option *opt __used,
220 const char *str, int unset __used)
223 parse_probe_event(str);
228 static int open_default_vmlinux(void)
231 char fname[MAX_PATH_LEN];
236 pr_debug("uname() failed.\n");
239 session.release = uts.release;
240 for (i = 0; i < NR_SEARCH_PATH; i++) {
241 ret = snprintf(fname, MAX_PATH_LEN,
242 default_search_path[i], session.release);
243 if (ret >= MAX_PATH_LEN || ret < 0) {
244 pr_debug("Filename(%d,%s) is too long.\n", i,
249 pr_debug("try to open %s\n", fname);
250 fd = open(fname, O_RDONLY);
258 static const char * const probe_usage[] = {
259 "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
260 "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
264 static const struct option options[] = {
265 OPT_BOOLEAN('v', "verbose", &verbose,
266 "be more verbose (show parsed arguments, etc)"),
268 OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
269 "vmlinux/module pathname"),
271 OPT_CALLBACK('a', "add", NULL,
273 "FUNC[+OFFS|%return] [ARG ...]",
275 "FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
277 "probe point definition, where\n"
278 "\t\tGRP:\tGroup name (optional)\n"
279 "\t\tNAME:\tEvent name\n"
280 "\t\tFUNC:\tFunction name\n"
281 "\t\tOFFS:\tOffset from function entry (in byte)\n"
282 "\t\t%return:\tPut the probe at function return\n"
284 "\t\tARG:\tProbe argument (only \n"
286 "\t\tSRC:\tSource code path\n"
287 "\t\tRLN:\tRelative line number from function entry.\n"
288 "\t\tALN:\tAbsolute line number in file.\n"
289 "\t\tARG:\tProbe argument (local variable name or\n"
291 "\t\t\tkprobe-tracer argument format is supported.)\n",
292 opt_add_probe_event),
296 static int write_new_event(int fd, const char *buf)
300 ret = write(fd, buf, strlen(buf));
302 die("Failed to create event.");
304 printf("Added new event: %s\n", buf);
309 #define MAX_CMDLEN 256
311 static int synthesize_probe_event(struct probe_point *pp)
315 pp->probes[0] = buf = zalloc(MAX_CMDLEN);
317 die("Failed to allocate memory by zalloc.");
318 ret = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
319 if (ret <= 0 || ret >= MAX_CMDLEN)
323 for (i = 0; i < pp->nr_args; i++) {
324 ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s",
326 if (ret <= 0 || ret >= MAX_CMDLEN - len)
339 int cmd_probe(int argc, const char **argv, const char *prefix __used)
342 struct probe_point *pp;
343 char buf[MAX_CMDLEN];
345 argc = parse_options(argc, argv, options, probe_usage,
346 PARSE_OPT_STOP_AT_NON_OPTION);
347 for (i = 0; i < argc; i++)
348 parse_probe_event(argv[i]);
350 if (session.nr_probe == 0)
351 usage_with_options(probe_usage, options);
353 if (session.need_dwarf)
355 semantic_error("Debuginfo-analysis is not supported");
356 #else /* !NO_LIBDWARF */
357 pr_debug("Some probes require debuginfo.\n");
360 fd = open(session.vmlinux, O_RDONLY);
362 fd = open_default_vmlinux();
364 if (session.need_dwarf)
365 die("Could not open vmlinux/module file.");
367 pr_warning("Could not open vmlinux/module file."
368 " Try to use symbols.\n");
372 /* Searching probe points */
373 for (j = 0; j < session.nr_probe; j++) {
374 pp = &session.probes[j];
378 lseek(fd, SEEK_SET, 0);
379 ret = find_probepoint(fd, pp);
381 if (session.need_dwarf)
382 die("Could not analyze debuginfo.");
384 pr_warning("An error occurred in debuginfo analysis. Try to use symbols.\n");
387 if (ret == 0) /* No error but failed to find probe point. */
388 die("No probe point found.");
393 #endif /* !NO_LIBDWARF */
395 /* Synthesize probes without dwarf */
396 for (j = 0; j < session.nr_probe; j++) {
397 pp = &session.probes[j];
398 if (pp->found) /* This probe is already found. */
401 ret = synthesize_probe_event(pp);
403 semantic_error("probe point is too long.");
405 die("Failed to synthesize a probe point.");
408 /* Settng up probe points */
409 snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);
410 fd = open(buf, O_WRONLY, O_APPEND);
413 die("kprobe_events file does not exist - please rebuild with CONFIG_KPROBE_TRACER.");
415 die("Could not open kprobe_events file: %s",
418 for (j = 0; j < session.nr_probe; j++) {
419 pp = &session.probes[j];
420 if (pp->found == 1) {
421 snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n",
422 pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP,
423 pp->function, pp->offset, pp->probes[0]);
424 write_new_event(fd, buf);
426 for (i = 0; i < pp->found; i++) {
427 snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n",
428 pp->retprobe ? 'r' : 'p',
430 pp->function, pp->offset, i,
432 write_new_event(fd, buf);