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413d37d1 MH |
1 | /* |
2 | * kprobe based kernel tracer | |
3 | * | |
4 | * Created 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 version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
19 | ||
20 | #include <linux/module.h> | |
21 | #include <linux/uaccess.h> | |
22 | #include <linux/kprobes.h> | |
23 | #include <linux/seq_file.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/smp.h> | |
26 | #include <linux/debugfs.h> | |
27 | #include <linux/types.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/ctype.h> | |
30 | #include <linux/ptrace.h> | |
31 | ||
32 | #include "trace.h" | |
33 | #include "trace_output.h" | |
34 | ||
35 | #define TRACE_KPROBE_ARGS 6 | |
36 | #define MAX_ARGSTR_LEN 63 | |
37 | ||
38 | /* currently, trace_kprobe only supports X86. */ | |
39 | ||
40 | struct fetch_func { | |
41 | unsigned long (*func)(struct pt_regs *, void *); | |
42 | void *data; | |
43 | }; | |
44 | ||
45 | static __kprobes unsigned long call_fetch(struct fetch_func *f, | |
46 | struct pt_regs *regs) | |
47 | { | |
48 | return f->func(regs, f->data); | |
49 | } | |
50 | ||
51 | /* fetch handlers */ | |
52 | static __kprobes unsigned long fetch_register(struct pt_regs *regs, | |
53 | void *offset) | |
54 | { | |
55 | return regs_get_register(regs, (unsigned int)((unsigned long)offset)); | |
56 | } | |
57 | ||
58 | static __kprobes unsigned long fetch_stack(struct pt_regs *regs, | |
59 | void *num) | |
60 | { | |
61 | return regs_get_kernel_stack_nth(regs, | |
62 | (unsigned int)((unsigned long)num)); | |
63 | } | |
64 | ||
65 | static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr) | |
66 | { | |
67 | unsigned long retval; | |
68 | ||
69 | if (probe_kernel_address(addr, retval)) | |
70 | return 0; | |
71 | return retval; | |
72 | } | |
73 | ||
74 | static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num) | |
75 | { | |
76 | return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num)); | |
77 | } | |
78 | ||
79 | static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs, | |
80 | void *dummy) | |
81 | { | |
82 | return regs_return_value(regs); | |
83 | } | |
84 | ||
85 | static __kprobes unsigned long fetch_ip(struct pt_regs *regs, void *dummy) | |
86 | { | |
87 | return instruction_pointer(regs); | |
88 | } | |
89 | ||
90 | static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs, | |
91 | void *dummy) | |
92 | { | |
93 | return kernel_stack_pointer(regs); | |
94 | } | |
95 | ||
96 | /* Memory fetching by symbol */ | |
97 | struct symbol_cache { | |
98 | char *symbol; | |
99 | long offset; | |
100 | unsigned long addr; | |
101 | }; | |
102 | ||
103 | static unsigned long update_symbol_cache(struct symbol_cache *sc) | |
104 | { | |
105 | sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol); | |
106 | if (sc->addr) | |
107 | sc->addr += sc->offset; | |
108 | return sc->addr; | |
109 | } | |
110 | ||
111 | static void free_symbol_cache(struct symbol_cache *sc) | |
112 | { | |
113 | kfree(sc->symbol); | |
114 | kfree(sc); | |
115 | } | |
116 | ||
117 | static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset) | |
118 | { | |
119 | struct symbol_cache *sc; | |
120 | ||
121 | if (!sym || strlen(sym) == 0) | |
122 | return NULL; | |
123 | sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL); | |
124 | if (!sc) | |
125 | return NULL; | |
126 | ||
127 | sc->symbol = kstrdup(sym, GFP_KERNEL); | |
128 | if (!sc->symbol) { | |
129 | kfree(sc); | |
130 | return NULL; | |
131 | } | |
132 | sc->offset = offset; | |
133 | ||
134 | update_symbol_cache(sc); | |
135 | return sc; | |
136 | } | |
137 | ||
138 | static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data) | |
139 | { | |
140 | struct symbol_cache *sc = data; | |
141 | ||
142 | if (sc->addr) | |
143 | return fetch_memory(regs, (void *)sc->addr); | |
144 | else | |
145 | return 0; | |
146 | } | |
147 | ||
148 | /* Special indirect memory access interface */ | |
149 | struct indirect_fetch_data { | |
150 | struct fetch_func orig; | |
151 | long offset; | |
152 | }; | |
153 | ||
154 | static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data) | |
155 | { | |
156 | struct indirect_fetch_data *ind = data; | |
157 | unsigned long addr; | |
158 | ||
159 | addr = call_fetch(&ind->orig, regs); | |
160 | if (addr) { | |
161 | addr += ind->offset; | |
162 | return fetch_memory(regs, (void *)addr); | |
163 | } else | |
164 | return 0; | |
165 | } | |
166 | ||
167 | static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data) | |
168 | { | |
169 | if (data->orig.func == fetch_indirect) | |
170 | free_indirect_fetch_data(data->orig.data); | |
171 | else if (data->orig.func == fetch_symbol) | |
172 | free_symbol_cache(data->orig.data); | |
173 | kfree(data); | |
174 | } | |
175 | ||
176 | /** | |
177 | * kprobe_trace_core | |
178 | */ | |
179 | ||
180 | struct trace_probe { | |
181 | struct list_head list; | |
182 | union { | |
183 | struct kprobe kp; | |
184 | struct kretprobe rp; | |
185 | }; | |
186 | const char *symbol; /* symbol name */ | |
187 | unsigned int nr_args; | |
188 | struct fetch_func args[TRACE_KPROBE_ARGS]; | |
189 | struct ftrace_event_call call; | |
190 | }; | |
191 | ||
192 | static int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs); | |
193 | static int kretprobe_trace_func(struct kretprobe_instance *ri, | |
194 | struct pt_regs *regs); | |
195 | ||
196 | static __kprobes int probe_is_return(struct trace_probe *tp) | |
197 | { | |
198 | return (tp->rp.handler == kretprobe_trace_func); | |
199 | } | |
200 | ||
201 | static __kprobes const char *probe_symbol(struct trace_probe *tp) | |
202 | { | |
203 | return tp->symbol ? tp->symbol : "unknown"; | |
204 | } | |
205 | ||
206 | static __kprobes long probe_offset(struct trace_probe *tp) | |
207 | { | |
208 | return (probe_is_return(tp)) ? tp->rp.kp.offset : tp->kp.offset; | |
209 | } | |
210 | ||
211 | static __kprobes void *probe_address(struct trace_probe *tp) | |
212 | { | |
213 | return (probe_is_return(tp)) ? tp->rp.kp.addr : tp->kp.addr; | |
214 | } | |
215 | ||
216 | static int trace_arg_string(char *buf, size_t n, struct fetch_func *ff) | |
217 | { | |
218 | int ret = -EINVAL; | |
219 | ||
220 | if (ff->func == fetch_argument) | |
221 | ret = snprintf(buf, n, "a%lu", (unsigned long)ff->data); | |
222 | else if (ff->func == fetch_register) { | |
223 | const char *name; | |
224 | name = regs_query_register_name((unsigned int)((long)ff->data)); | |
225 | ret = snprintf(buf, n, "%%%s", name); | |
226 | } else if (ff->func == fetch_stack) | |
227 | ret = snprintf(buf, n, "s%lu", (unsigned long)ff->data); | |
228 | else if (ff->func == fetch_memory) | |
229 | ret = snprintf(buf, n, "@0x%p", ff->data); | |
230 | else if (ff->func == fetch_symbol) { | |
231 | struct symbol_cache *sc = ff->data; | |
232 | ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset); | |
233 | } else if (ff->func == fetch_retvalue) | |
234 | ret = snprintf(buf, n, "rv"); | |
235 | else if (ff->func == fetch_ip) | |
236 | ret = snprintf(buf, n, "ra"); | |
237 | else if (ff->func == fetch_stack_address) | |
238 | ret = snprintf(buf, n, "sa"); | |
239 | else if (ff->func == fetch_indirect) { | |
240 | struct indirect_fetch_data *id = ff->data; | |
241 | size_t l = 0; | |
242 | ret = snprintf(buf, n, "%+ld(", id->offset); | |
243 | if (ret >= n) | |
244 | goto end; | |
245 | l += ret; | |
246 | ret = trace_arg_string(buf + l, n - l, &id->orig); | |
247 | if (ret < 0) | |
248 | goto end; | |
249 | l += ret; | |
250 | ret = snprintf(buf + l, n - l, ")"); | |
251 | ret += l; | |
252 | } | |
253 | end: | |
254 | if (ret >= n) | |
255 | return -ENOSPC; | |
256 | return ret; | |
257 | } | |
258 | ||
259 | static int register_probe_event(struct trace_probe *tp); | |
260 | static void unregister_probe_event(struct trace_probe *tp); | |
261 | ||
262 | static DEFINE_MUTEX(probe_lock); | |
263 | static LIST_HEAD(probe_list); | |
264 | ||
265 | static struct trace_probe *alloc_trace_probe(const char *symbol, | |
266 | const char *event) | |
267 | { | |
268 | struct trace_probe *tp; | |
269 | ||
270 | tp = kzalloc(sizeof(struct trace_probe), GFP_KERNEL); | |
271 | if (!tp) | |
272 | return ERR_PTR(-ENOMEM); | |
273 | ||
274 | if (symbol) { | |
275 | tp->symbol = kstrdup(symbol, GFP_KERNEL); | |
276 | if (!tp->symbol) | |
277 | goto error; | |
278 | } | |
279 | if (event) { | |
280 | tp->call.name = kstrdup(event, GFP_KERNEL); | |
281 | if (!tp->call.name) | |
282 | goto error; | |
283 | } | |
284 | ||
285 | INIT_LIST_HEAD(&tp->list); | |
286 | return tp; | |
287 | error: | |
288 | kfree(tp->symbol); | |
289 | kfree(tp); | |
290 | return ERR_PTR(-ENOMEM); | |
291 | } | |
292 | ||
293 | static void free_trace_probe(struct trace_probe *tp) | |
294 | { | |
295 | int i; | |
296 | ||
297 | for (i = 0; i < tp->nr_args; i++) | |
298 | if (tp->args[i].func == fetch_symbol) | |
299 | free_symbol_cache(tp->args[i].data); | |
300 | else if (tp->args[i].func == fetch_indirect) | |
301 | free_indirect_fetch_data(tp->args[i].data); | |
302 | ||
303 | kfree(tp->call.name); | |
304 | kfree(tp->symbol); | |
305 | kfree(tp); | |
306 | } | |
307 | ||
308 | static struct trace_probe *find_probe_event(const char *event) | |
309 | { | |
310 | struct trace_probe *tp; | |
311 | ||
312 | list_for_each_entry(tp, &probe_list, list) | |
313 | if (tp->call.name && !strcmp(tp->call.name, event)) | |
314 | return tp; | |
315 | return NULL; | |
316 | } | |
317 | ||
318 | static void __unregister_trace_probe(struct trace_probe *tp) | |
319 | { | |
320 | if (probe_is_return(tp)) | |
321 | unregister_kretprobe(&tp->rp); | |
322 | else | |
323 | unregister_kprobe(&tp->kp); | |
324 | } | |
325 | ||
326 | /* Unregister a trace_probe and probe_event: call with locking probe_lock */ | |
327 | static void unregister_trace_probe(struct trace_probe *tp) | |
328 | { | |
329 | if (tp->call.name) | |
330 | unregister_probe_event(tp); | |
331 | __unregister_trace_probe(tp); | |
332 | list_del(&tp->list); | |
333 | } | |
334 | ||
335 | /* Register a trace_probe and probe_event */ | |
336 | static int register_trace_probe(struct trace_probe *tp) | |
337 | { | |
338 | struct trace_probe *old_tp; | |
339 | int ret; | |
340 | ||
341 | mutex_lock(&probe_lock); | |
342 | ||
343 | if (probe_is_return(tp)) | |
344 | ret = register_kretprobe(&tp->rp); | |
345 | else | |
346 | ret = register_kprobe(&tp->kp); | |
347 | ||
348 | if (ret) { | |
349 | pr_warning("Could not insert probe(%d)\n", ret); | |
350 | if (ret == -EILSEQ) { | |
351 | pr_warning("Probing address(0x%p) is not an " | |
352 | "instruction boundary.\n", | |
353 | probe_address(tp)); | |
354 | ret = -EINVAL; | |
355 | } | |
356 | goto end; | |
357 | } | |
358 | /* register as an event */ | |
359 | if (tp->call.name) { | |
360 | old_tp = find_probe_event(tp->call.name); | |
361 | if (old_tp) { | |
362 | /* delete old event */ | |
363 | unregister_trace_probe(old_tp); | |
364 | free_trace_probe(old_tp); | |
365 | } | |
366 | ret = register_probe_event(tp); | |
367 | if (ret) { | |
368 | pr_warning("Faild to register probe event(%d)\n", ret); | |
369 | __unregister_trace_probe(tp); | |
370 | } | |
371 | } | |
372 | list_add_tail(&tp->list, &probe_list); | |
373 | end: | |
374 | mutex_unlock(&probe_lock); | |
375 | return ret; | |
376 | } | |
377 | ||
378 | /* Split symbol and offset. */ | |
379 | static int split_symbol_offset(char *symbol, long *offset) | |
380 | { | |
381 | char *tmp; | |
382 | int ret; | |
383 | ||
384 | if (!offset) | |
385 | return -EINVAL; | |
386 | ||
387 | tmp = strchr(symbol, '+'); | |
388 | if (!tmp) | |
389 | tmp = strchr(symbol, '-'); | |
390 | ||
391 | if (tmp) { | |
392 | /* skip sign because strict_strtol doesn't accept '+' */ | |
393 | ret = strict_strtol(tmp + 1, 0, offset); | |
394 | if (ret) | |
395 | return ret; | |
396 | if (*tmp == '-') | |
397 | *offset = -(*offset); | |
398 | *tmp = '\0'; | |
399 | } else | |
400 | *offset = 0; | |
401 | return 0; | |
402 | } | |
403 | ||
404 | #define PARAM_MAX_ARGS 16 | |
405 | #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) | |
406 | ||
407 | static int parse_trace_arg(char *arg, struct fetch_func *ff, int is_return) | |
408 | { | |
409 | int ret = 0; | |
410 | unsigned long param; | |
411 | long offset; | |
412 | char *tmp; | |
413 | ||
414 | switch (arg[0]) { | |
415 | case 'a': /* argument */ | |
416 | ret = strict_strtoul(arg + 1, 10, ¶m); | |
417 | if (ret || param > PARAM_MAX_ARGS) | |
418 | ret = -EINVAL; | |
419 | else { | |
420 | ff->func = fetch_argument; | |
421 | ff->data = (void *)param; | |
422 | } | |
423 | break; | |
424 | case 'r': /* retval or retaddr */ | |
425 | if (is_return && arg[1] == 'v') { | |
426 | ff->func = fetch_retvalue; | |
427 | ff->data = NULL; | |
428 | } else if (is_return && arg[1] == 'a') { | |
429 | ff->func = fetch_ip; | |
430 | ff->data = NULL; | |
431 | } else | |
432 | ret = -EINVAL; | |
433 | break; | |
434 | case '%': /* named register */ | |
435 | ret = regs_query_register_offset(arg + 1); | |
436 | if (ret >= 0) { | |
437 | ff->func = fetch_register; | |
438 | ff->data = (void *)(unsigned long)ret; | |
439 | ret = 0; | |
440 | } | |
441 | break; | |
442 | case 's': /* stack */ | |
443 | if (arg[1] == 'a') { | |
444 | ff->func = fetch_stack_address; | |
445 | ff->data = NULL; | |
446 | } else { | |
447 | ret = strict_strtoul(arg + 1, 10, ¶m); | |
448 | if (ret || param > PARAM_MAX_STACK) | |
449 | ret = -EINVAL; | |
450 | else { | |
451 | ff->func = fetch_stack; | |
452 | ff->data = (void *)param; | |
453 | } | |
454 | } | |
455 | break; | |
456 | case '@': /* memory or symbol */ | |
457 | if (isdigit(arg[1])) { | |
458 | ret = strict_strtoul(arg + 1, 0, ¶m); | |
459 | if (ret) | |
460 | break; | |
461 | ff->func = fetch_memory; | |
462 | ff->data = (void *)param; | |
463 | } else { | |
464 | ret = split_symbol_offset(arg + 1, &offset); | |
465 | if (ret) | |
466 | break; | |
467 | ff->data = alloc_symbol_cache(arg + 1, | |
468 | offset); | |
469 | if (ff->data) | |
470 | ff->func = fetch_symbol; | |
471 | else | |
472 | ret = -EINVAL; | |
473 | } | |
474 | break; | |
475 | case '+': /* indirect memory */ | |
476 | case '-': | |
477 | tmp = strchr(arg, '('); | |
478 | if (!tmp) { | |
479 | ret = -EINVAL; | |
480 | break; | |
481 | } | |
482 | *tmp = '\0'; | |
483 | ret = strict_strtol(arg + 1, 0, &offset); | |
484 | if (ret) | |
485 | break; | |
486 | if (arg[0] == '-') | |
487 | offset = -offset; | |
488 | arg = tmp + 1; | |
489 | tmp = strrchr(arg, ')'); | |
490 | if (tmp) { | |
491 | struct indirect_fetch_data *id; | |
492 | *tmp = '\0'; | |
493 | id = kzalloc(sizeof(struct indirect_fetch_data), | |
494 | GFP_KERNEL); | |
495 | if (!id) | |
496 | return -ENOMEM; | |
497 | id->offset = offset; | |
498 | ret = parse_trace_arg(arg, &id->orig, is_return); | |
499 | if (ret) | |
500 | kfree(id); | |
501 | else { | |
502 | ff->func = fetch_indirect; | |
503 | ff->data = (void *)id; | |
504 | } | |
505 | } else | |
506 | ret = -EINVAL; | |
507 | break; | |
508 | default: | |
509 | /* TODO: support custom handler */ | |
510 | ret = -EINVAL; | |
511 | } | |
512 | return ret; | |
513 | } | |
514 | ||
515 | static int create_trace_probe(int argc, char **argv) | |
516 | { | |
517 | /* | |
518 | * Argument syntax: | |
519 | * - Add kprobe: p[:EVENT] SYMBOL[+OFFS|-OFFS]|ADDRESS [FETCHARGS] | |
520 | * - Add kretprobe: r[:EVENT] SYMBOL[+0] [FETCHARGS] | |
521 | * Fetch args: | |
522 | * aN : fetch Nth of function argument. (N:0-) | |
523 | * rv : fetch return value | |
524 | * ra : fetch return address | |
525 | * sa : fetch stack address | |
526 | * sN : fetch Nth of stack (N:0-) | |
527 | * @ADDR : fetch memory at ADDR (ADDR should be in kernel) | |
528 | * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) | |
529 | * %REG : fetch register REG | |
530 | * Indirect memory fetch: | |
531 | * +|-offs(ARG) : fetch memory at ARG +|- offs address. | |
532 | */ | |
533 | struct trace_probe *tp; | |
534 | struct kprobe *kp; | |
535 | int i, ret = 0; | |
536 | int is_return = 0; | |
537 | char *symbol = NULL, *event = NULL; | |
538 | long offset = 0; | |
539 | void *addr = NULL; | |
540 | ||
541 | if (argc < 2) | |
542 | return -EINVAL; | |
543 | ||
544 | if (argv[0][0] == 'p') | |
545 | is_return = 0; | |
546 | else if (argv[0][0] == 'r') | |
547 | is_return = 1; | |
548 | else | |
549 | return -EINVAL; | |
550 | ||
551 | if (argv[0][1] == ':') { | |
552 | event = &argv[0][2]; | |
553 | if (strlen(event) == 0) { | |
554 | pr_info("Event name is not specifiled\n"); | |
555 | return -EINVAL; | |
556 | } | |
557 | } | |
558 | ||
559 | if (isdigit(argv[1][0])) { | |
560 | if (is_return) | |
561 | return -EINVAL; | |
562 | /* an address specified */ | |
563 | ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr); | |
564 | if (ret) | |
565 | return ret; | |
566 | } else { | |
567 | /* a symbol specified */ | |
568 | symbol = argv[1]; | |
569 | /* TODO: support .init module functions */ | |
570 | ret = split_symbol_offset(symbol, &offset); | |
571 | if (ret) | |
572 | return ret; | |
573 | if (offset && is_return) | |
574 | return -EINVAL; | |
575 | } | |
576 | ||
577 | /* setup a probe */ | |
578 | tp = alloc_trace_probe(symbol, event); | |
579 | if (IS_ERR(tp)) | |
580 | return PTR_ERR(tp); | |
581 | ||
582 | if (is_return) { | |
583 | kp = &tp->rp.kp; | |
584 | tp->rp.handler = kretprobe_trace_func; | |
585 | } else { | |
586 | kp = &tp->kp; | |
587 | tp->kp.pre_handler = kprobe_trace_func; | |
588 | } | |
589 | ||
590 | if (tp->symbol) { | |
591 | kp->symbol_name = tp->symbol; | |
592 | kp->offset = offset; | |
593 | } else | |
594 | kp->addr = addr; | |
595 | ||
596 | /* parse arguments */ | |
597 | argc -= 2; argv += 2; ret = 0; | |
598 | for (i = 0; i < argc && i < TRACE_KPROBE_ARGS; i++) { | |
599 | if (strlen(argv[i]) > MAX_ARGSTR_LEN) { | |
600 | pr_info("Argument%d(%s) is too long.\n", i, argv[i]); | |
601 | ret = -ENOSPC; | |
602 | goto error; | |
603 | } | |
604 | ret = parse_trace_arg(argv[i], &tp->args[i], is_return); | |
605 | if (ret) | |
606 | goto error; | |
607 | } | |
608 | tp->nr_args = i; | |
609 | ||
610 | ret = register_trace_probe(tp); | |
611 | if (ret) | |
612 | goto error; | |
613 | return 0; | |
614 | ||
615 | error: | |
616 | free_trace_probe(tp); | |
617 | return ret; | |
618 | } | |
619 | ||
620 | static void cleanup_all_probes(void) | |
621 | { | |
622 | struct trace_probe *tp; | |
623 | ||
624 | mutex_lock(&probe_lock); | |
625 | /* TODO: Use batch unregistration */ | |
626 | while (!list_empty(&probe_list)) { | |
627 | tp = list_entry(probe_list.next, struct trace_probe, list); | |
628 | unregister_trace_probe(tp); | |
629 | free_trace_probe(tp); | |
630 | } | |
631 | mutex_unlock(&probe_lock); | |
632 | } | |
633 | ||
634 | ||
635 | /* Probes listing interfaces */ | |
636 | static void *probes_seq_start(struct seq_file *m, loff_t *pos) | |
637 | { | |
638 | mutex_lock(&probe_lock); | |
639 | return seq_list_start(&probe_list, *pos); | |
640 | } | |
641 | ||
642 | static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
643 | { | |
644 | return seq_list_next(v, &probe_list, pos); | |
645 | } | |
646 | ||
647 | static void probes_seq_stop(struct seq_file *m, void *v) | |
648 | { | |
649 | mutex_unlock(&probe_lock); | |
650 | } | |
651 | ||
652 | static int probes_seq_show(struct seq_file *m, void *v) | |
653 | { | |
654 | struct trace_probe *tp = v; | |
655 | int i, ret; | |
656 | char buf[MAX_ARGSTR_LEN + 1]; | |
657 | ||
658 | seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p'); | |
659 | if (tp->call.name) | |
660 | seq_printf(m, ":%s", tp->call.name); | |
661 | ||
662 | if (tp->symbol) | |
663 | seq_printf(m, " %s%+ld", probe_symbol(tp), probe_offset(tp)); | |
664 | else | |
665 | seq_printf(m, " 0x%p", probe_address(tp)); | |
666 | ||
667 | for (i = 0; i < tp->nr_args; i++) { | |
668 | ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); | |
669 | if (ret < 0) { | |
670 | pr_warning("Argument%d decoding error(%d).\n", i, ret); | |
671 | return ret; | |
672 | } | |
673 | seq_printf(m, " %s", buf); | |
674 | } | |
675 | seq_printf(m, "\n"); | |
676 | return 0; | |
677 | } | |
678 | ||
679 | static const struct seq_operations probes_seq_op = { | |
680 | .start = probes_seq_start, | |
681 | .next = probes_seq_next, | |
682 | .stop = probes_seq_stop, | |
683 | .show = probes_seq_show | |
684 | }; | |
685 | ||
686 | static int probes_open(struct inode *inode, struct file *file) | |
687 | { | |
688 | if ((file->f_mode & FMODE_WRITE) && | |
689 | (file->f_flags & O_TRUNC)) | |
690 | cleanup_all_probes(); | |
691 | ||
692 | return seq_open(file, &probes_seq_op); | |
693 | } | |
694 | ||
695 | static int command_trace_probe(const char *buf) | |
696 | { | |
697 | char **argv; | |
698 | int argc = 0, ret = 0; | |
699 | ||
700 | argv = argv_split(GFP_KERNEL, buf, &argc); | |
701 | if (!argv) | |
702 | return -ENOMEM; | |
703 | ||
704 | if (argc) | |
705 | ret = create_trace_probe(argc, argv); | |
706 | ||
707 | argv_free(argv); | |
708 | return ret; | |
709 | } | |
710 | ||
711 | #define WRITE_BUFSIZE 128 | |
712 | ||
713 | static ssize_t probes_write(struct file *file, const char __user *buffer, | |
714 | size_t count, loff_t *ppos) | |
715 | { | |
716 | char *kbuf, *tmp; | |
717 | int ret; | |
718 | size_t done; | |
719 | size_t size; | |
720 | ||
721 | kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL); | |
722 | if (!kbuf) | |
723 | return -ENOMEM; | |
724 | ||
725 | ret = done = 0; | |
726 | while (done < count) { | |
727 | size = count - done; | |
728 | if (size >= WRITE_BUFSIZE) | |
729 | size = WRITE_BUFSIZE - 1; | |
730 | if (copy_from_user(kbuf, buffer + done, size)) { | |
731 | ret = -EFAULT; | |
732 | goto out; | |
733 | } | |
734 | kbuf[size] = '\0'; | |
735 | tmp = strchr(kbuf, '\n'); | |
736 | if (tmp) { | |
737 | *tmp = '\0'; | |
738 | size = tmp - kbuf + 1; | |
739 | } else if (done + size < count) { | |
740 | pr_warning("Line length is too long: " | |
741 | "Should be less than %d.", WRITE_BUFSIZE); | |
742 | ret = -EINVAL; | |
743 | goto out; | |
744 | } | |
745 | done += size; | |
746 | /* Remove comments */ | |
747 | tmp = strchr(kbuf, '#'); | |
748 | if (tmp) | |
749 | *tmp = '\0'; | |
750 | ||
751 | ret = command_trace_probe(kbuf); | |
752 | if (ret) | |
753 | goto out; | |
754 | } | |
755 | ret = done; | |
756 | out: | |
757 | kfree(kbuf); | |
758 | return ret; | |
759 | } | |
760 | ||
761 | static const struct file_operations kprobe_events_ops = { | |
762 | .owner = THIS_MODULE, | |
763 | .open = probes_open, | |
764 | .read = seq_read, | |
765 | .llseek = seq_lseek, | |
766 | .release = seq_release, | |
767 | .write = probes_write, | |
768 | }; | |
769 | ||
770 | /* Kprobe handler */ | |
771 | static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs) | |
772 | { | |
773 | struct trace_probe *tp = container_of(kp, struct trace_probe, kp); | |
774 | struct kprobe_trace_entry *entry; | |
775 | struct ring_buffer_event *event; | |
776 | int size, i, pc; | |
777 | unsigned long irq_flags; | |
778 | struct ftrace_event_call *call = &event_kprobe; | |
779 | ||
780 | if (&tp->call.name) | |
781 | call = &tp->call; | |
782 | ||
783 | local_save_flags(irq_flags); | |
784 | pc = preempt_count(); | |
785 | ||
786 | size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args); | |
787 | ||
788 | event = trace_current_buffer_lock_reserve(TRACE_KPROBE, size, | |
789 | irq_flags, pc); | |
790 | if (!event) | |
791 | return 0; | |
792 | ||
793 | entry = ring_buffer_event_data(event); | |
794 | entry->nargs = tp->nr_args; | |
795 | entry->ip = (unsigned long)kp->addr; | |
796 | for (i = 0; i < tp->nr_args; i++) | |
797 | entry->args[i] = call_fetch(&tp->args[i], regs); | |
798 | ||
799 | if (!filter_current_check_discard(call, entry, event)) | |
800 | trace_nowake_buffer_unlock_commit(event, irq_flags, pc); | |
801 | return 0; | |
802 | } | |
803 | ||
804 | /* Kretprobe handler */ | |
805 | static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri, | |
806 | struct pt_regs *regs) | |
807 | { | |
808 | struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp); | |
809 | struct kretprobe_trace_entry *entry; | |
810 | struct ring_buffer_event *event; | |
811 | int size, i, pc; | |
812 | unsigned long irq_flags; | |
813 | struct ftrace_event_call *call = &event_kretprobe; | |
814 | ||
815 | if (&tp->call.name) | |
816 | call = &tp->call; | |
817 | ||
818 | local_save_flags(irq_flags); | |
819 | pc = preempt_count(); | |
820 | ||
821 | size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args); | |
822 | ||
823 | event = trace_current_buffer_lock_reserve(TRACE_KRETPROBE, size, | |
824 | irq_flags, pc); | |
825 | if (!event) | |
826 | return 0; | |
827 | ||
828 | entry = ring_buffer_event_data(event); | |
829 | entry->nargs = tp->nr_args; | |
830 | entry->func = (unsigned long)probe_address(tp); | |
831 | entry->ret_ip = (unsigned long)ri->ret_addr; | |
832 | for (i = 0; i < tp->nr_args; i++) | |
833 | entry->args[i] = call_fetch(&tp->args[i], regs); | |
834 | ||
835 | if (!filter_current_check_discard(call, entry, event)) | |
836 | trace_nowake_buffer_unlock_commit(event, irq_flags, pc); | |
837 | ||
838 | return 0; | |
839 | } | |
840 | ||
841 | /* Event entry printers */ | |
842 | enum print_line_t | |
843 | print_kprobe_event(struct trace_iterator *iter, int flags) | |
844 | { | |
845 | struct kprobe_trace_entry *field; | |
846 | struct trace_seq *s = &iter->seq; | |
847 | int i; | |
848 | ||
849 | trace_assign_type(field, iter->ent); | |
850 | ||
851 | if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) | |
852 | goto partial; | |
853 | ||
854 | if (!trace_seq_puts(s, ":")) | |
855 | goto partial; | |
856 | ||
857 | for (i = 0; i < field->nargs; i++) | |
858 | if (!trace_seq_printf(s, " 0x%lx", field->args[i])) | |
859 | goto partial; | |
860 | ||
861 | if (!trace_seq_puts(s, "\n")) | |
862 | goto partial; | |
863 | ||
864 | return TRACE_TYPE_HANDLED; | |
865 | partial: | |
866 | return TRACE_TYPE_PARTIAL_LINE; | |
867 | } | |
868 | ||
869 | enum print_line_t | |
870 | print_kretprobe_event(struct trace_iterator *iter, int flags) | |
871 | { | |
872 | struct kretprobe_trace_entry *field; | |
873 | struct trace_seq *s = &iter->seq; | |
874 | int i; | |
875 | ||
876 | trace_assign_type(field, iter->ent); | |
877 | ||
878 | if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) | |
879 | goto partial; | |
880 | ||
881 | if (!trace_seq_puts(s, " <- ")) | |
882 | goto partial; | |
883 | ||
884 | if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) | |
885 | goto partial; | |
886 | ||
887 | if (!trace_seq_puts(s, ":")) | |
888 | goto partial; | |
889 | ||
890 | for (i = 0; i < field->nargs; i++) | |
891 | if (!trace_seq_printf(s, " 0x%lx", field->args[i])) | |
892 | goto partial; | |
893 | ||
894 | if (!trace_seq_puts(s, "\n")) | |
895 | goto partial; | |
896 | ||
897 | return TRACE_TYPE_HANDLED; | |
898 | partial: | |
899 | return TRACE_TYPE_PARTIAL_LINE; | |
900 | } | |
901 | ||
902 | static struct trace_event kprobe_trace_event = { | |
903 | .type = TRACE_KPROBE, | |
904 | .trace = print_kprobe_event, | |
905 | }; | |
906 | ||
907 | static struct trace_event kretprobe_trace_event = { | |
908 | .type = TRACE_KRETPROBE, | |
909 | .trace = print_kretprobe_event, | |
910 | }; | |
911 | ||
912 | static int probe_event_enable(struct ftrace_event_call *call) | |
913 | { | |
914 | struct trace_probe *tp = (struct trace_probe *)call->data; | |
915 | ||
916 | if (probe_is_return(tp)) | |
917 | return enable_kretprobe(&tp->rp); | |
918 | else | |
919 | return enable_kprobe(&tp->kp); | |
920 | } | |
921 | ||
922 | static void probe_event_disable(struct ftrace_event_call *call) | |
923 | { | |
924 | struct trace_probe *tp = (struct trace_probe *)call->data; | |
925 | ||
926 | if (probe_is_return(tp)) | |
927 | disable_kretprobe(&tp->rp); | |
928 | else | |
929 | disable_kprobe(&tp->kp); | |
930 | } | |
931 | ||
932 | static int probe_event_raw_init(struct ftrace_event_call *event_call) | |
933 | { | |
934 | INIT_LIST_HEAD(&event_call->fields); | |
935 | init_preds(event_call); | |
936 | return 0; | |
937 | } | |
938 | ||
939 | #undef DEFINE_FIELD | |
940 | #define DEFINE_FIELD(type, item, name, is_signed) \ | |
941 | do { \ | |
942 | ret = trace_define_field(event_call, #type, name, \ | |
943 | offsetof(typeof(field), item), \ | |
944 | sizeof(field.item), is_signed, \ | |
945 | FILTER_OTHER); \ | |
946 | if (ret) \ | |
947 | return ret; \ | |
948 | } while (0) | |
949 | ||
950 | static int kprobe_event_define_fields(struct ftrace_event_call *event_call) | |
951 | { | |
952 | int ret, i; | |
953 | struct kprobe_trace_entry field; | |
954 | char buf[MAX_ARGSTR_LEN + 1]; | |
955 | struct trace_probe *tp = (struct trace_probe *)event_call->data; | |
956 | ||
957 | ret = trace_define_common_fields(event_call); | |
958 | if (!ret) | |
959 | return ret; | |
960 | ||
961 | DEFINE_FIELD(unsigned long, ip, "ip", 0); | |
962 | DEFINE_FIELD(int, nargs, "nargs", 1); | |
963 | for (i = 0; i < tp->nr_args; i++) { | |
964 | /* Set argN as a field */ | |
965 | sprintf(buf, "arg%d", i); | |
966 | DEFINE_FIELD(unsigned long, args[i], buf, 0); | |
967 | /* Set argument string as an alias field */ | |
968 | ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); | |
969 | if (ret < 0) | |
970 | return ret; | |
971 | DEFINE_FIELD(unsigned long, args[i], buf, 0); | |
972 | } | |
973 | return 0; | |
974 | } | |
975 | ||
976 | static int kretprobe_event_define_fields(struct ftrace_event_call *event_call) | |
977 | { | |
978 | int ret, i; | |
979 | struct kretprobe_trace_entry field; | |
980 | char buf[MAX_ARGSTR_LEN + 1]; | |
981 | struct trace_probe *tp = (struct trace_probe *)event_call->data; | |
982 | ||
983 | ret = trace_define_common_fields(event_call); | |
984 | if (!ret) | |
985 | return ret; | |
986 | ||
987 | DEFINE_FIELD(unsigned long, func, "func", 0); | |
988 | DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0); | |
989 | DEFINE_FIELD(int, nargs, "nargs", 1); | |
990 | for (i = 0; i < tp->nr_args; i++) { | |
991 | /* Set argN as a field */ | |
992 | sprintf(buf, "arg%d", i); | |
993 | DEFINE_FIELD(unsigned long, args[i], buf, 0); | |
994 | /* Set argument string as an alias field */ | |
995 | ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); | |
996 | if (ret < 0) | |
997 | return ret; | |
998 | DEFINE_FIELD(unsigned long, args[i], buf, 0); | |
999 | } | |
1000 | return 0; | |
1001 | } | |
1002 | ||
1003 | static int __probe_event_show_format(struct trace_seq *s, | |
1004 | struct trace_probe *tp, const char *fmt, | |
1005 | const char *arg) | |
1006 | { | |
1007 | int i, ret; | |
1008 | char buf[MAX_ARGSTR_LEN + 1]; | |
1009 | ||
1010 | /* Show aliases */ | |
1011 | for (i = 0; i < tp->nr_args; i++) { | |
1012 | ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); | |
1013 | if (ret < 0) | |
1014 | return ret; | |
1015 | if (!trace_seq_printf(s, "\talias: %s;\toriginal: arg%d;\n", | |
1016 | buf, i)) | |
1017 | return 0; | |
1018 | } | |
1019 | /* Show format */ | |
1020 | if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt)) | |
1021 | return 0; | |
1022 | ||
1023 | for (i = 0; i < tp->nr_args; i++) | |
1024 | if (!trace_seq_puts(s, " 0x%lx")) | |
1025 | return 0; | |
1026 | ||
1027 | if (!trace_seq_printf(s, "\", %s", arg)) | |
1028 | return 0; | |
1029 | ||
1030 | for (i = 0; i < tp->nr_args; i++) | |
1031 | if (!trace_seq_printf(s, ", arg%d", i)) | |
1032 | return 0; | |
1033 | ||
1034 | return trace_seq_puts(s, "\n"); | |
1035 | } | |
1036 | ||
1037 | #undef SHOW_FIELD | |
1038 | #define SHOW_FIELD(type, item, name) \ | |
1039 | do { \ | |
1040 | ret = trace_seq_printf(s, "\tfield: " #type " %s;\t" \ | |
1041 | "offset:%u;tsize:%u;\n", name, \ | |
1042 | (unsigned int)offsetof(typeof(field), item),\ | |
1043 | (unsigned int)sizeof(type)); \ | |
1044 | if (!ret) \ | |
1045 | return 0; \ | |
1046 | } while (0) | |
1047 | ||
1048 | static int kprobe_event_show_format(struct ftrace_event_call *call, | |
1049 | struct trace_seq *s) | |
1050 | { | |
1051 | struct kprobe_trace_entry field __attribute__((unused)); | |
1052 | int ret, i; | |
1053 | char buf[8]; | |
1054 | struct trace_probe *tp = (struct trace_probe *)call->data; | |
1055 | ||
1056 | SHOW_FIELD(unsigned long, ip, "ip"); | |
1057 | SHOW_FIELD(int, nargs, "nargs"); | |
1058 | ||
1059 | /* Show fields */ | |
1060 | for (i = 0; i < tp->nr_args; i++) { | |
1061 | sprintf(buf, "arg%d", i); | |
1062 | SHOW_FIELD(unsigned long, args[i], buf); | |
1063 | } | |
1064 | trace_seq_puts(s, "\n"); | |
1065 | ||
1066 | return __probe_event_show_format(s, tp, "%lx:", "ip"); | |
1067 | } | |
1068 | ||
1069 | static int kretprobe_event_show_format(struct ftrace_event_call *call, | |
1070 | struct trace_seq *s) | |
1071 | { | |
1072 | struct kretprobe_trace_entry field __attribute__((unused)); | |
1073 | int ret, i; | |
1074 | char buf[8]; | |
1075 | struct trace_probe *tp = (struct trace_probe *)call->data; | |
1076 | ||
1077 | SHOW_FIELD(unsigned long, func, "func"); | |
1078 | SHOW_FIELD(unsigned long, ret_ip, "ret_ip"); | |
1079 | SHOW_FIELD(int, nargs, "nargs"); | |
1080 | ||
1081 | /* Show fields */ | |
1082 | for (i = 0; i < tp->nr_args; i++) { | |
1083 | sprintf(buf, "arg%d", i); | |
1084 | SHOW_FIELD(unsigned long, args[i], buf); | |
1085 | } | |
1086 | trace_seq_puts(s, "\n"); | |
1087 | ||
1088 | return __probe_event_show_format(s, tp, "%lx <- %lx:", | |
1089 | "func, ret_ip"); | |
1090 | } | |
1091 | ||
1092 | static int register_probe_event(struct trace_probe *tp) | |
1093 | { | |
1094 | struct ftrace_event_call *call = &tp->call; | |
1095 | int ret; | |
1096 | ||
1097 | /* Initialize ftrace_event_call */ | |
1098 | call->system = "kprobes"; | |
1099 | if (probe_is_return(tp)) { | |
1100 | call->event = &kretprobe_trace_event; | |
1101 | call->id = TRACE_KRETPROBE; | |
1102 | call->raw_init = probe_event_raw_init; | |
1103 | call->show_format = kretprobe_event_show_format; | |
1104 | call->define_fields = kretprobe_event_define_fields; | |
1105 | } else { | |
1106 | call->event = &kprobe_trace_event; | |
1107 | call->id = TRACE_KPROBE; | |
1108 | call->raw_init = probe_event_raw_init; | |
1109 | call->show_format = kprobe_event_show_format; | |
1110 | call->define_fields = kprobe_event_define_fields; | |
1111 | } | |
1112 | call->enabled = 1; | |
1113 | call->regfunc = probe_event_enable; | |
1114 | call->unregfunc = probe_event_disable; | |
1115 | call->data = tp; | |
1116 | ret = trace_add_event_call(call); | |
1117 | if (ret) | |
1118 | pr_info("Failed to register kprobe event: %s\n", call->name); | |
1119 | return ret; | |
1120 | } | |
1121 | ||
1122 | static void unregister_probe_event(struct trace_probe *tp) | |
1123 | { | |
1124 | /* | |
1125 | * Prevent to unregister event itself because the event is shared | |
1126 | * among other probes. | |
1127 | */ | |
1128 | tp->call.event = NULL; | |
1129 | trace_remove_event_call(&tp->call); | |
1130 | } | |
1131 | ||
1132 | /* Make a debugfs interface for controling probe points */ | |
1133 | static __init int init_kprobe_trace(void) | |
1134 | { | |
1135 | struct dentry *d_tracer; | |
1136 | struct dentry *entry; | |
1137 | int ret; | |
1138 | ||
1139 | ret = register_ftrace_event(&kprobe_trace_event); | |
1140 | if (!ret) { | |
1141 | pr_warning("Could not register kprobe_trace_event type.\n"); | |
1142 | return 0; | |
1143 | } | |
1144 | ret = register_ftrace_event(&kretprobe_trace_event); | |
1145 | if (!ret) { | |
1146 | pr_warning("Could not register kretprobe_trace_event type.\n"); | |
1147 | return 0; | |
1148 | } | |
1149 | ||
1150 | d_tracer = tracing_init_dentry(); | |
1151 | if (!d_tracer) | |
1152 | return 0; | |
1153 | ||
1154 | entry = debugfs_create_file("kprobe_events", 0644, d_tracer, | |
1155 | NULL, &kprobe_events_ops); | |
1156 | ||
1157 | if (!entry) | |
1158 | pr_warning("Could not create debugfs " | |
1159 | "'kprobe_events' entry\n"); | |
1160 | return 0; | |
1161 | } | |
1162 | fs_initcall(init_kprobe_trace); | |
1163 | ||
1164 | ||
1165 | #ifdef CONFIG_FTRACE_STARTUP_TEST | |
1166 | ||
1167 | static int kprobe_trace_selftest_target(int a1, int a2, int a3, | |
1168 | int a4, int a5, int a6) | |
1169 | { | |
1170 | return a1 + a2 + a3 + a4 + a5 + a6; | |
1171 | } | |
1172 | ||
1173 | static __init int kprobe_trace_self_tests_init(void) | |
1174 | { | |
1175 | int ret; | |
1176 | int (*target)(int, int, int, int, int, int); | |
1177 | ||
1178 | target = kprobe_trace_selftest_target; | |
1179 | ||
1180 | pr_info("Testing kprobe tracing: "); | |
1181 | ||
1182 | ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target " | |
1183 | "a1 a2 a3 a4 a5 a6"); | |
1184 | if (WARN_ON_ONCE(ret)) | |
1185 | pr_warning("error enabling function entry\n"); | |
1186 | ||
1187 | ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target " | |
1188 | "ra rv"); | |
1189 | if (WARN_ON_ONCE(ret)) | |
1190 | pr_warning("error enabling function return\n"); | |
1191 | ||
1192 | ret = target(1, 2, 3, 4, 5, 6); | |
1193 | ||
1194 | cleanup_all_probes(); | |
1195 | ||
1196 | pr_cont("OK\n"); | |
1197 | return 0; | |
1198 | } | |
1199 | ||
1200 | late_initcall(kprobe_trace_self_tests_init); | |
1201 | ||
1202 | #endif |