2 * probe-event.c : perf-probe definition to kprobe_events format converter
4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23 #include <sys/utsname.h>
24 #include <sys/types.h>
40 #include "parse-events.h" /* For debugfs_path */
41 #include "probe-event.h"
43 #define MAX_CMDLEN 256
44 #define MAX_PROBE_ARGS 128
45 #define PERFPROBE_GROUP "probe"
47 #define semantic_error(msg ...) die("Semantic error :" msg)
49 /* If there is no space to write, returns -E2BIG. */
50 static int e_snprintf(char *str, size_t size, const char *format, ...)
55 ret = vsnprintf(str, size, format, ap);
62 /* Parse probepoint definition. */
63 static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
70 * perf probe FUNC[+OFFS|%return][@SRC]
73 ptr = strpbrk(arg, ":+@%");
79 /* Check arg is function or file and copy it */
80 if (strchr(arg, '.')) /* File */
81 pp->file = strdup(arg);
83 pp->function = strdup(arg);
84 DIE_IF(pp->file == NULL && pp->function == NULL);
86 /* Parse other options */
90 ptr = strpbrk(arg, ":+@%");
96 case ':': /* Line number */
97 pp->line = strtoul(arg, &tmp, 0);
99 semantic_error("There is non-digit charactor"
102 case '+': /* Byte offset from a symbol */
103 pp->offset = strtoul(arg, &tmp, 0);
105 semantic_error("There is non-digit charactor"
108 case '@': /* File name */
110 semantic_error("SRC@SRC is not allowed.");
111 pp->file = strdup(arg);
112 DIE_IF(pp->file == NULL);
114 semantic_error("@SRC must be the last "
117 case '%': /* Probe places */
118 if (strcmp(arg, "return") == 0) {
120 } else /* Others not supported yet */
121 semantic_error("%%%s is not supported.", arg);
124 DIE_IF("Program has a bug.");
129 /* Exclusion check */
130 if (pp->line && pp->offset)
131 semantic_error("Offset can't be used with line number.");
133 if (!pp->line && pp->file && !pp->function)
134 semantic_error("File always requires line number.");
136 if (pp->offset && !pp->function)
137 semantic_error("Offset requires an entry function.");
139 if (pp->retprobe && !pp->function)
140 semantic_error("Return probe requires an entry function.");
142 if ((pp->offset || pp->line) && pp->retprobe)
143 semantic_error("Offset/Line can't be used with return probe.");
145 pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
146 pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
149 /* Parse perf-probe event definition */
150 int parse_perf_probe_event(const char *str, struct probe_point *pp)
153 int argc, i, need_dwarf = 0;
155 argv = argv_split(str, &argc);
157 die("argv_split failed.");
158 if (argc > MAX_PROBE_ARGS + 1)
159 semantic_error("Too many arguments");
161 /* Parse probe point */
162 parse_perf_probe_probepoint(argv[0], pp);
163 if (pp->file || pp->line)
166 /* Copy arguments and ensure return probe has no C argument */
167 pp->nr_args = argc - 1;
168 pp->args = zalloc(sizeof(char *) * pp->nr_args);
169 for (i = 0; i < pp->nr_args; i++) {
170 pp->args[i] = strdup(argv[i + 1]);
172 die("Failed to copy argument.");
173 if (is_c_varname(pp->args[i])) {
175 semantic_error("You can't specify local"
176 " variable for kretprobe");
185 /* Parse kprobe_events event into struct probe_point */
186 void parse_trace_kprobe_event(const char *str, char **group, char **event,
187 struct probe_point *pp)
194 pr_debug("Parsing kprobe_events: %s\n", str);
195 argv = argv_split(str, &argc);
197 die("argv_split failed.");
199 semantic_error("Too less arguments.");
201 /* Scan event and group name. */
202 ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
203 &pr, (float *)(void *)group, (float *)(void *)event);
205 semantic_error("Failed to parse event name: %s", argv[0]);
206 pr_debug("Group:%s Event:%s probe:%c\n", *group, *event, pr);
211 pp->retprobe = (pr == 'r');
213 /* Scan function name and offset */
214 ret = sscanf(argv[1], "%a[^+]+%d", (float *)(void *)&pp->function, &pp->offset);
218 /* kprobe_events doesn't have this information */
222 pp->nr_args = argc - 2;
223 pp->args = zalloc(sizeof(char *) * pp->nr_args);
224 for (i = 0; i < pp->nr_args; i++) {
225 p = strchr(argv[i + 2], '=');
226 if (p) /* We don't need which register is assigned. */
228 pp->args[i] = strdup(argv[i + 2]);
230 die("Failed to copy argument.");
237 int synthesize_perf_probe_event(struct probe_point *pp)
240 char offs[64] = "", line[64] = "";
243 pp->probes[0] = buf = zalloc(MAX_CMDLEN);
245 die("Failed to allocate memory by zalloc.");
247 ret = e_snprintf(offs, 64, "+%d", pp->offset);
252 ret = e_snprintf(line, 64, ":%d", pp->line);
258 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function,
259 offs, pp->retprobe ? "%return" : "", line);
261 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->file, line);
266 for (i = 0; i < pp->nr_args; i++) {
267 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
282 int synthesize_trace_kprobe_event(struct probe_point *pp)
287 pp->probes[0] = buf = zalloc(MAX_CMDLEN);
289 die("Failed to allocate memory by zalloc.");
290 ret = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
295 for (i = 0; i < pp->nr_args; i++) {
296 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
311 static int open_kprobe_events(int flags, int mode)
316 ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path);
318 die("Failed to make kprobe_events path.");
320 ret = open(buf, flags, mode);
323 die("kprobe_events file does not exist -"
324 " please rebuild with CONFIG_KPROBE_TRACER.");
326 die("Could not open kprobe_events file: %s",
332 /* Get raw string list of current kprobe_events */
333 static struct strlist *get_trace_kprobe_event_rawlist(int fd)
337 char buf[MAX_CMDLEN];
341 sl = strlist__new(true, NULL);
343 fp = fdopen(dup(fd), "r");
345 p = fgets(buf, MAX_CMDLEN, fp);
352 ret = strlist__add(sl, buf);
354 die("strlist__add failed: %s", strerror(-ret));
361 /* Free and zero clear probe_point */
362 static void clear_probe_point(struct probe_point *pp)
370 for (i = 0; i < pp->nr_args; i++)
374 for (i = 0; i < pp->found; i++)
376 memset(pp, 0, sizeof(pp));
379 /* List up current perf-probe events */
380 void show_perf_probe_events(void)
385 struct probe_point pp;
386 struct strlist *rawlist;
387 struct str_node *ent;
389 fd = open_kprobe_events(O_RDONLY, 0);
390 rawlist = get_trace_kprobe_event_rawlist(fd);
393 for (i = 0; i < strlist__nr_entries(rawlist); i++) {
394 ent = strlist__entry(rawlist, i);
395 parse_trace_kprobe_event(ent->s, &group, &event, &pp);
396 synthesize_perf_probe_event(&pp);
397 printf("[%s:%s]\t%s\n", group, event, pp.probes[0]);
400 clear_probe_point(&pp);
403 strlist__delete(rawlist);
406 /* Get current perf-probe event names */
407 static struct strlist *get_perf_event_names(int fd)
411 struct strlist *sl, *rawlist;
412 struct str_node *ent;
414 rawlist = get_trace_kprobe_event_rawlist(fd);
416 sl = strlist__new(false, NULL);
417 for (i = 0; i < strlist__nr_entries(rawlist); i++) {
418 ent = strlist__entry(rawlist, i);
419 parse_trace_kprobe_event(ent->s, &group, &event, NULL);
420 strlist__add(sl, event);
424 strlist__delete(rawlist);
429 static int write_trace_kprobe_event(int fd, const char *buf)
433 ret = write(fd, buf, strlen(buf));
435 die("Failed to create event.");
437 printf("Added new event: %s\n", buf);
442 static void get_new_event_name(char *buf, size_t len, const char *base,
443 struct strlist *namelist)
446 for (i = 0; i < MAX_EVENT_INDEX; i++) {
447 ret = e_snprintf(buf, len, "%s_%d", base, i);
449 die("snprintf() failed: %s", strerror(-ret));
450 if (!strlist__has_entry(namelist, buf))
453 if (i == MAX_EVENT_INDEX)
454 die("Too many events are on the same function.");
457 void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
460 struct probe_point *pp;
461 char buf[MAX_CMDLEN];
463 struct strlist *namelist;
465 fd = open_kprobe_events(O_RDWR, O_APPEND);
466 /* Get current event names */
467 namelist = get_perf_event_names(fd);
469 for (j = 0; j < nr_probes; j++) {
471 for (i = 0; i < pp->found; i++) {
472 /* Get an unused new event name */
473 get_new_event_name(event, 64, pp->function, namelist);
474 snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n",
475 pp->retprobe ? 'r' : 'p',
476 PERFPROBE_GROUP, event,
478 write_trace_kprobe_event(fd, buf);
479 /* Add added event name to namelist */
480 strlist__add(namelist, event);