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50656eec MH |
1 | /* |
2 | * probe-event.c : perf-probe definition to kprobe_events format converter | |
3 | * | |
4 | * Written by Masami Hiramatsu <mhiramat@redhat.com> | |
5 | * | |
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. | |
10 | * | |
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. | |
15 | * | |
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. | |
19 | * | |
20 | */ | |
21 | ||
22 | #define _GNU_SOURCE | |
23 | #include <sys/utsname.h> | |
24 | #include <sys/types.h> | |
25 | #include <sys/stat.h> | |
26 | #include <fcntl.h> | |
27 | #include <errno.h> | |
28 | #include <stdio.h> | |
29 | #include <unistd.h> | |
30 | #include <stdlib.h> | |
31 | #include <string.h> | |
4de189fe MH |
32 | #include <stdarg.h> |
33 | #include <limits.h> | |
50656eec MH |
34 | |
35 | #undef _GNU_SOURCE | |
36 | #include "event.h" | |
e1c01d61 | 37 | #include "string.h" |
4de189fe | 38 | #include "strlist.h" |
50656eec MH |
39 | #include "debug.h" |
40 | #include "parse-events.h" /* For debugfs_path */ | |
41 | #include "probe-event.h" | |
42 | ||
43 | #define MAX_CMDLEN 256 | |
44 | #define MAX_PROBE_ARGS 128 | |
45 | #define PERFPROBE_GROUP "probe" | |
46 | ||
47 | #define semantic_error(msg ...) die("Semantic error :" msg) | |
48 | ||
4de189fe MH |
49 | /* If there is no space to write, returns -E2BIG. */ |
50 | static int e_snprintf(char *str, size_t size, const char *format, ...) | |
51 | { | |
52 | int ret; | |
53 | va_list ap; | |
54 | va_start(ap, format); | |
55 | ret = vsnprintf(str, size, format, ap); | |
56 | va_end(ap); | |
57 | if (ret >= (int)size) | |
58 | ret = -E2BIG; | |
59 | return ret; | |
60 | } | |
61 | ||
50656eec MH |
62 | /* Parse probepoint definition. */ |
63 | static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp) | |
64 | { | |
65 | char *ptr, *tmp; | |
66 | char c, nc = 0; | |
67 | /* | |
68 | * <Syntax> | |
69 | * perf probe SRC:LN | |
70 | * perf probe FUNC[+OFFS|%return][@SRC] | |
71 | */ | |
72 | ||
73 | ptr = strpbrk(arg, ":+@%"); | |
74 | if (ptr) { | |
75 | nc = *ptr; | |
76 | *ptr++ = '\0'; | |
77 | } | |
78 | ||
79 | /* Check arg is function or file and copy it */ | |
80 | if (strchr(arg, '.')) /* File */ | |
81 | pp->file = strdup(arg); | |
82 | else /* Function */ | |
83 | pp->function = strdup(arg); | |
84 | DIE_IF(pp->file == NULL && pp->function == NULL); | |
85 | ||
86 | /* Parse other options */ | |
87 | while (ptr) { | |
88 | arg = ptr; | |
89 | c = nc; | |
90 | ptr = strpbrk(arg, ":+@%"); | |
91 | if (ptr) { | |
92 | nc = *ptr; | |
93 | *ptr++ = '\0'; | |
94 | } | |
95 | switch (c) { | |
96 | case ':': /* Line number */ | |
97 | pp->line = strtoul(arg, &tmp, 0); | |
98 | if (*tmp != '\0') | |
99 | semantic_error("There is non-digit charactor" | |
100 | " in line number."); | |
101 | break; | |
102 | case '+': /* Byte offset from a symbol */ | |
103 | pp->offset = strtoul(arg, &tmp, 0); | |
104 | if (*tmp != '\0') | |
105 | semantic_error("There is non-digit charactor" | |
106 | " in offset."); | |
107 | break; | |
108 | case '@': /* File name */ | |
109 | if (pp->file) | |
110 | semantic_error("SRC@SRC is not allowed."); | |
111 | pp->file = strdup(arg); | |
112 | DIE_IF(pp->file == NULL); | |
113 | if (ptr) | |
114 | semantic_error("@SRC must be the last " | |
115 | "option."); | |
116 | break; | |
117 | case '%': /* Probe places */ | |
118 | if (strcmp(arg, "return") == 0) { | |
119 | pp->retprobe = 1; | |
120 | } else /* Others not supported yet */ | |
121 | semantic_error("%%%s is not supported.", arg); | |
122 | break; | |
123 | default: | |
124 | DIE_IF("Program has a bug."); | |
125 | break; | |
126 | } | |
127 | } | |
128 | ||
129 | /* Exclusion check */ | |
130 | if (pp->line && pp->offset) | |
131 | semantic_error("Offset can't be used with line number."); | |
132 | ||
133 | if (!pp->line && pp->file && !pp->function) | |
134 | semantic_error("File always requires line number."); | |
135 | ||
136 | if (pp->offset && !pp->function) | |
137 | semantic_error("Offset requires an entry function."); | |
138 | ||
139 | if (pp->retprobe && !pp->function) | |
140 | semantic_error("Return probe requires an entry function."); | |
141 | ||
142 | if ((pp->offset || pp->line) && pp->retprobe) | |
143 | semantic_error("Offset/Line can't be used with return probe."); | |
144 | ||
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); | |
147 | } | |
148 | ||
149 | /* Parse perf-probe event definition */ | |
150 | int parse_perf_probe_event(const char *str, struct probe_point *pp) | |
151 | { | |
e1c01d61 | 152 | char **argv; |
50656eec MH |
153 | int argc, i, need_dwarf = 0; |
154 | ||
e1c01d61 MH |
155 | argv = argv_split(str, &argc); |
156 | if (!argv) | |
157 | die("argv_split failed."); | |
158 | if (argc > MAX_PROBE_ARGS + 1) | |
159 | semantic_error("Too many arguments"); | |
50656eec MH |
160 | |
161 | /* Parse probe point */ | |
162 | parse_perf_probe_probepoint(argv[0], pp); | |
50656eec MH |
163 | if (pp->file || pp->line) |
164 | need_dwarf = 1; | |
165 | ||
e1c01d61 | 166 | /* Copy arguments and ensure return probe has no C argument */ |
50656eec | 167 | pp->nr_args = argc - 1; |
e1c01d61 MH |
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]); | |
171 | if (!pp->args[i]) | |
172 | die("Failed to copy argument."); | |
50656eec MH |
173 | if (is_c_varname(pp->args[i])) { |
174 | if (pp->retprobe) | |
175 | semantic_error("You can't specify local" | |
176 | " variable for kretprobe"); | |
177 | need_dwarf = 1; | |
178 | } | |
e1c01d61 | 179 | } |
50656eec | 180 | |
e1c01d61 | 181 | argv_free(argv); |
50656eec MH |
182 | return need_dwarf; |
183 | } | |
184 | ||
4de189fe MH |
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) | |
188 | { | |
189 | char pr; | |
190 | char *p; | |
191 | int ret, i, argc; | |
192 | char **argv; | |
193 | ||
194 | pr_debug("Parsing kprobe_events: %s\n", str); | |
195 | argv = argv_split(str, &argc); | |
196 | if (!argv) | |
197 | die("argv_split failed."); | |
198 | if (argc < 2) | |
199 | semantic_error("Too less arguments."); | |
200 | ||
201 | /* Scan event and group name. */ | |
202 | ret = sscanf(argv[0], "%c:%m[^/ \t]/%m[^ \t]", | |
203 | &pr, group, event); | |
204 | if (ret != 3) | |
205 | semantic_error("Failed to parse event name: %s", argv[0]); | |
206 | pr_debug("Group:%s Event:%s probe:%c\n", *group, *event, pr); | |
207 | ||
208 | if (!pp) | |
209 | goto end; | |
210 | ||
211 | pp->retprobe = (pr == 'r'); | |
212 | ||
213 | /* Scan function name and offset */ | |
214 | ret = sscanf(argv[1], "%m[^+]+%d", &pp->function, &pp->offset); | |
215 | if (ret == 1) | |
216 | pp->offset = 0; | |
217 | ||
218 | /* kprobe_events doesn't have this information */ | |
219 | pp->line = 0; | |
220 | pp->file = NULL; | |
221 | ||
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. */ | |
227 | *p = '\0'; | |
228 | pp->args[i] = strdup(argv[i + 2]); | |
229 | if (!pp->args[i]) | |
230 | die("Failed to copy argument."); | |
231 | } | |
232 | ||
233 | end: | |
234 | argv_free(argv); | |
235 | } | |
236 | ||
237 | int synthesize_perf_probe_event(struct probe_point *pp) | |
238 | { | |
239 | char *buf; | |
240 | char offs[64] = "", line[64] = ""; | |
241 | int i, len, ret; | |
242 | ||
243 | pp->probes[0] = buf = zalloc(MAX_CMDLEN); | |
244 | if (!buf) | |
245 | die("Failed to allocate memory by zalloc."); | |
246 | if (pp->offset) { | |
247 | ret = e_snprintf(offs, 64, "+%d", pp->offset); | |
248 | if (ret <= 0) | |
249 | goto error; | |
250 | } | |
251 | if (pp->line) { | |
252 | ret = e_snprintf(line, 64, ":%d", pp->line); | |
253 | if (ret <= 0) | |
254 | goto error; | |
255 | } | |
256 | ||
257 | if (pp->function) | |
258 | ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function, | |
259 | offs, pp->retprobe ? "%return" : "", line); | |
260 | else | |
261 | ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->file, line); | |
262 | if (ret <= 0) | |
263 | goto error; | |
264 | len = ret; | |
265 | ||
266 | for (i = 0; i < pp->nr_args; i++) { | |
267 | ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s", | |
268 | pp->args[i]); | |
269 | if (ret <= 0) | |
270 | goto error; | |
271 | len += ret; | |
272 | } | |
273 | pp->found = 1; | |
274 | ||
275 | return pp->found; | |
276 | error: | |
277 | free(pp->probes[0]); | |
278 | ||
279 | return ret; | |
280 | } | |
281 | ||
50656eec MH |
282 | int synthesize_trace_kprobe_event(struct probe_point *pp) |
283 | { | |
284 | char *buf; | |
285 | int i, len, ret; | |
286 | ||
287 | pp->probes[0] = buf = zalloc(MAX_CMDLEN); | |
288 | if (!buf) | |
289 | die("Failed to allocate memory by zalloc."); | |
4de189fe MH |
290 | ret = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset); |
291 | if (ret <= 0) | |
50656eec MH |
292 | goto error; |
293 | len = ret; | |
294 | ||
295 | for (i = 0; i < pp->nr_args; i++) { | |
4de189fe MH |
296 | ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s", |
297 | pp->args[i]); | |
298 | if (ret <= 0) | |
50656eec MH |
299 | goto error; |
300 | len += ret; | |
301 | } | |
302 | pp->found = 1; | |
303 | ||
304 | return pp->found; | |
305 | error: | |
306 | free(pp->probes[0]); | |
50656eec MH |
307 | |
308 | return ret; | |
309 | } | |
310 | ||
4de189fe MH |
311 | static int open_kprobe_events(int flags, int mode) |
312 | { | |
313 | char buf[PATH_MAX]; | |
314 | int ret; | |
315 | ||
316 | ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path); | |
317 | if (ret < 0) | |
318 | die("Failed to make kprobe_events path."); | |
319 | ||
320 | ret = open(buf, flags, mode); | |
321 | if (ret < 0) { | |
322 | if (errno == ENOENT) | |
323 | die("kprobe_events file does not exist -" | |
324 | " please rebuild with CONFIG_KPROBE_TRACER."); | |
325 | else | |
326 | die("Could not open kprobe_events file: %s", | |
327 | strerror(errno)); | |
328 | } | |
329 | return ret; | |
330 | } | |
331 | ||
332 | /* Get raw string list of current kprobe_events */ | |
333 | static struct strlist *get_trace_kprobe_event_rawlist(int fd) | |
334 | { | |
335 | int ret, idx; | |
336 | FILE *fp; | |
337 | char buf[MAX_CMDLEN]; | |
338 | char *p; | |
339 | struct strlist *sl; | |
340 | ||
341 | sl = strlist__new(true, NULL); | |
342 | ||
343 | fp = fdopen(dup(fd), "r"); | |
344 | while (!feof(fp)) { | |
345 | p = fgets(buf, MAX_CMDLEN, fp); | |
346 | if (!p) | |
347 | break; | |
348 | ||
349 | idx = strlen(p) - 1; | |
350 | if (p[idx] == '\n') | |
351 | p[idx] = '\0'; | |
352 | ret = strlist__add(sl, buf); | |
353 | if (ret < 0) | |
354 | die("strlist__add failed: %s", strerror(-ret)); | |
355 | } | |
356 | fclose(fp); | |
357 | ||
358 | return sl; | |
359 | } | |
360 | ||
361 | /* Free and zero clear probe_point */ | |
362 | static void clear_probe_point(struct probe_point *pp) | |
363 | { | |
364 | int i; | |
365 | ||
366 | if (pp->function) | |
367 | free(pp->function); | |
368 | if (pp->file) | |
369 | free(pp->file); | |
370 | for (i = 0; i < pp->nr_args; i++) | |
371 | free(pp->args[i]); | |
372 | if (pp->args) | |
373 | free(pp->args); | |
374 | for (i = 0; i < pp->found; i++) | |
375 | free(pp->probes[i]); | |
376 | memset(pp, 0, sizeof(pp)); | |
377 | } | |
378 | ||
379 | /* List up current perf-probe events */ | |
380 | void show_perf_probe_events(void) | |
381 | { | |
382 | unsigned int i; | |
383 | int fd; | |
384 | char *group, *event; | |
385 | struct probe_point pp; | |
386 | struct strlist *rawlist; | |
387 | struct str_node *ent; | |
388 | ||
389 | fd = open_kprobe_events(O_RDONLY, 0); | |
390 | rawlist = get_trace_kprobe_event_rawlist(fd); | |
391 | close(fd); | |
392 | ||
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]); | |
398 | free(group); | |
399 | free(event); | |
400 | clear_probe_point(&pp); | |
401 | } | |
402 | ||
403 | strlist__delete(rawlist); | |
404 | } | |
405 | ||
50656eec MH |
406 | static int write_trace_kprobe_event(int fd, const char *buf) |
407 | { | |
408 | int ret; | |
409 | ||
410 | ret = write(fd, buf, strlen(buf)); | |
411 | if (ret <= 0) | |
412 | die("Failed to create event."); | |
413 | else | |
414 | printf("Added new event: %s\n", buf); | |
415 | ||
416 | return ret; | |
417 | } | |
418 | ||
419 | void add_trace_kprobe_events(struct probe_point *probes, int nr_probes) | |
420 | { | |
421 | int i, j, fd; | |
422 | struct probe_point *pp; | |
423 | char buf[MAX_CMDLEN]; | |
424 | ||
4de189fe | 425 | fd = open_kprobe_events(O_WRONLY, O_APPEND); |
50656eec MH |
426 | |
427 | for (j = 0; j < nr_probes; j++) { | |
428 | pp = probes + j; | |
429 | if (pp->found == 1) { | |
430 | snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n", | |
431 | pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP, | |
432 | pp->function, pp->offset, pp->probes[0]); | |
433 | write_trace_kprobe_event(fd, buf); | |
434 | } else | |
435 | for (i = 0; i < pp->found; i++) { | |
436 | snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n", | |
437 | pp->retprobe ? 'r' : 'p', | |
438 | PERFPROBE_GROUP, | |
439 | pp->function, pp->offset, i, | |
440 | pp->probes[i]); | |
441 | write_trace_kprobe_event(fd, buf); | |
442 | } | |
443 | } | |
444 | close(fd); | |
445 | } |