1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Common code for probe-based Dynamic events.
4 *
5 * This code was copied from kernel/trace/trace_kprobe.c written by
6 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
7 *
8 * Updates to make this generic:
9 * Copyright (C) IBM Corporation, 2010-2011
10 * Author: Srikar Dronamraju
11 */
12 #define pr_fmt(fmt) "trace_probe: " fmt
13
14 #include "trace_probe.h"
15
16 #undef C
17 #define C(a, b) b
18
19 static const char *trace_probe_err_text[] = { ERRORS };
20
21 static const char *reserved_field_names[] = {
22 "common_type",
23 "common_flags",
24 "common_preempt_count",
25 "common_pid",
26 "common_tgid",
27 FIELD_STRING_IP,
28 FIELD_STRING_RETIP,
29 FIELD_STRING_FUNC,
30 };
31
32 /* Printing in basic type function template */
33 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
34 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
35 { \
36 trace_seq_printf(s, fmt, *(type *)data); \
37 return !trace_seq_has_overflowed(s); \
38 } \
39 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
40
41 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
42 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
43 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
44 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
45 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
48 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
49 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
53
PRINT_TYPE_FUNC_NAME(symbol)54 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
55 {
56 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
57 return !trace_seq_has_overflowed(s);
58 }
59 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
60
61 /* Print type function for string type */
PRINT_TYPE_FUNC_NAME(string)62 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
63 {
64 int len = *(u32 *)data >> 16;
65
66 if (!len)
67 trace_seq_puts(s, "(fault)");
68 else
69 trace_seq_printf(s, "\"%s\"",
70 (const char *)get_loc_data(data, ent));
71 return !trace_seq_has_overflowed(s);
72 }
73
74 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
75
76 /* Fetch type information table */
77 static const struct fetch_type probe_fetch_types[] = {
78 /* Special types */
79 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
80 "__data_loc char[]"),
81 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1,
82 "__data_loc char[]"),
83 /* Basic types */
84 ASSIGN_FETCH_TYPE(u8, u8, 0),
85 ASSIGN_FETCH_TYPE(u16, u16, 0),
86 ASSIGN_FETCH_TYPE(u32, u32, 0),
87 ASSIGN_FETCH_TYPE(u64, u64, 0),
88 ASSIGN_FETCH_TYPE(s8, u8, 1),
89 ASSIGN_FETCH_TYPE(s16, u16, 1),
90 ASSIGN_FETCH_TYPE(s32, u32, 1),
91 ASSIGN_FETCH_TYPE(s64, u64, 1),
92 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
93 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
94 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
95 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
96 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
97
98 ASSIGN_FETCH_TYPE_END
99 };
100
find_fetch_type(const char * type)101 static const struct fetch_type *find_fetch_type(const char *type)
102 {
103 int i;
104
105 if (!type)
106 type = DEFAULT_FETCH_TYPE_STR;
107
108 /* Special case: bitfield */
109 if (*type == 'b') {
110 unsigned long bs;
111
112 type = strchr(type, '/');
113 if (!type)
114 goto fail;
115
116 type++;
117 if (kstrtoul(type, 0, &bs))
118 goto fail;
119
120 switch (bs) {
121 case 8:
122 return find_fetch_type("u8");
123 case 16:
124 return find_fetch_type("u16");
125 case 32:
126 return find_fetch_type("u32");
127 case 64:
128 return find_fetch_type("u64");
129 default:
130 goto fail;
131 }
132 }
133
134 for (i = 0; probe_fetch_types[i].name; i++) {
135 if (strcmp(type, probe_fetch_types[i].name) == 0)
136 return &probe_fetch_types[i];
137 }
138
139 fail:
140 return NULL;
141 }
142
143 static struct trace_probe_log trace_probe_log;
144
trace_probe_log_init(const char * subsystem,int argc,const char ** argv)145 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
146 {
147 trace_probe_log.subsystem = subsystem;
148 trace_probe_log.argc = argc;
149 trace_probe_log.argv = argv;
150 trace_probe_log.index = 0;
151 }
152
trace_probe_log_clear(void)153 void trace_probe_log_clear(void)
154 {
155 memset(&trace_probe_log, 0, sizeof(trace_probe_log));
156 }
157
trace_probe_log_set_index(int index)158 void trace_probe_log_set_index(int index)
159 {
160 trace_probe_log.index = index;
161 }
162
__trace_probe_log_err(int offset,int err_type)163 void __trace_probe_log_err(int offset, int err_type)
164 {
165 char *command, *p;
166 int i, len = 0, pos = 0;
167
168 if (!trace_probe_log.argv)
169 return;
170
171 /* Recalculate the length and allocate buffer */
172 for (i = 0; i < trace_probe_log.argc; i++) {
173 if (i == trace_probe_log.index)
174 pos = len;
175 len += strlen(trace_probe_log.argv[i]) + 1;
176 }
177 command = kzalloc(len, GFP_KERNEL);
178 if (!command)
179 return;
180
181 if (trace_probe_log.index >= trace_probe_log.argc) {
182 /**
183 * Set the error position is next to the last arg + space.
184 * Note that len includes the terminal null and the cursor
185 * appears at pos + 1.
186 */
187 pos = len;
188 offset = 0;
189 }
190
191 /* And make a command string from argv array */
192 p = command;
193 for (i = 0; i < trace_probe_log.argc; i++) {
194 len = strlen(trace_probe_log.argv[i]);
195 strcpy(p, trace_probe_log.argv[i]);
196 p[len] = ' ';
197 p += len + 1;
198 }
199 *(p - 1) = '\0';
200
201 tracing_log_err(NULL, trace_probe_log.subsystem, command,
202 trace_probe_err_text, err_type, pos + offset);
203
204 kfree(command);
205 }
206
207 /* Split symbol and offset. */
traceprobe_split_symbol_offset(char * symbol,long * offset)208 int traceprobe_split_symbol_offset(char *symbol, long *offset)
209 {
210 char *tmp;
211 int ret;
212
213 if (!offset)
214 return -EINVAL;
215
216 tmp = strpbrk(symbol, "+-");
217 if (tmp) {
218 ret = kstrtol(tmp, 0, offset);
219 if (ret)
220 return ret;
221 *tmp = '\0';
222 } else
223 *offset = 0;
224
225 return 0;
226 }
227
228 /* @buf must has MAX_EVENT_NAME_LEN size */
traceprobe_parse_event_name(const char ** pevent,const char ** pgroup,char * buf,int offset)229 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
230 char *buf, int offset)
231 {
232 const char *slash, *event = *pevent;
233 int len;
234
235 slash = strchr(event, '/');
236 if (!slash)
237 slash = strchr(event, '.');
238
239 if (slash) {
240 if (slash == event) {
241 trace_probe_log_err(offset, NO_GROUP_NAME);
242 return -EINVAL;
243 }
244 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
245 trace_probe_log_err(offset, GROUP_TOO_LONG);
246 return -EINVAL;
247 }
248 strlcpy(buf, event, slash - event + 1);
249 if (!is_good_name(buf)) {
250 trace_probe_log_err(offset, BAD_GROUP_NAME);
251 return -EINVAL;
252 }
253 *pgroup = buf;
254 *pevent = slash + 1;
255 offset += slash - event + 1;
256 event = *pevent;
257 }
258 len = strlen(event);
259 if (len == 0) {
260 trace_probe_log_err(offset, NO_EVENT_NAME);
261 return -EINVAL;
262 } else if (len > MAX_EVENT_NAME_LEN) {
263 trace_probe_log_err(offset, EVENT_TOO_LONG);
264 return -EINVAL;
265 }
266 if (!is_good_name(event)) {
267 trace_probe_log_err(offset, BAD_EVENT_NAME);
268 return -EINVAL;
269 }
270 return 0;
271 }
272
273 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
274
parse_probe_vars(char * arg,const struct fetch_type * t,struct fetch_insn * code,unsigned int flags,int offs)275 static int parse_probe_vars(char *arg, const struct fetch_type *t,
276 struct fetch_insn *code, unsigned int flags, int offs)
277 {
278 unsigned long param;
279 int ret = 0;
280 int len;
281
282 if (flags & TPARG_FL_TPOINT) {
283 if (code->data)
284 return -EFAULT;
285 code->data = kstrdup(arg, GFP_KERNEL);
286 if (!code->data)
287 return -ENOMEM;
288 code->op = FETCH_OP_TP_ARG;
289 } else if (strcmp(arg, "retval") == 0) {
290 if (flags & TPARG_FL_RETURN) {
291 code->op = FETCH_OP_RETVAL;
292 } else {
293 trace_probe_log_err(offs, RETVAL_ON_PROBE);
294 ret = -EINVAL;
295 }
296 } else if ((len = str_has_prefix(arg, "stack"))) {
297 if (arg[len] == '\0') {
298 code->op = FETCH_OP_STACKP;
299 } else if (isdigit(arg[len])) {
300 ret = kstrtoul(arg + len, 10, ¶m);
301 if (ret) {
302 goto inval_var;
303 } else if ((flags & TPARG_FL_KERNEL) &&
304 param > PARAM_MAX_STACK) {
305 trace_probe_log_err(offs, BAD_STACK_NUM);
306 ret = -EINVAL;
307 } else {
308 code->op = FETCH_OP_STACK;
309 code->param = (unsigned int)param;
310 }
311 } else
312 goto inval_var;
313 } else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
314 code->op = FETCH_OP_COMM;
315 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
316 } else if (((flags & TPARG_FL_MASK) ==
317 (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
318 (len = str_has_prefix(arg, "arg"))) {
319 ret = kstrtoul(arg + len, 10, ¶m);
320 if (ret) {
321 goto inval_var;
322 } else if (!param || param > PARAM_MAX_STACK) {
323 trace_probe_log_err(offs, BAD_ARG_NUM);
324 return -EINVAL;
325 }
326 code->op = FETCH_OP_ARG;
327 code->param = (unsigned int)param - 1;
328 #endif
329 } else
330 goto inval_var;
331
332 return ret;
333
334 inval_var:
335 trace_probe_log_err(offs, BAD_VAR);
336 return -EINVAL;
337 }
338
str_to_immediate(char * str,unsigned long * imm)339 static int str_to_immediate(char *str, unsigned long *imm)
340 {
341 if (isdigit(str[0]))
342 return kstrtoul(str, 0, imm);
343 else if (str[0] == '-')
344 return kstrtol(str, 0, (long *)imm);
345 else if (str[0] == '+')
346 return kstrtol(str + 1, 0, (long *)imm);
347 return -EINVAL;
348 }
349
__parse_imm_string(char * str,char ** pbuf,int offs)350 static int __parse_imm_string(char *str, char **pbuf, int offs)
351 {
352 size_t len = strlen(str);
353
354 if (str[len - 1] != '"') {
355 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
356 return -EINVAL;
357 }
358 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
359 if (!*pbuf)
360 return -ENOMEM;
361 return 0;
362 }
363
364 /* Recursive argument parser */
365 static int
parse_probe_arg(char * arg,const struct fetch_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,unsigned int flags,int offs)366 parse_probe_arg(char *arg, const struct fetch_type *type,
367 struct fetch_insn **pcode, struct fetch_insn *end,
368 unsigned int flags, int offs)
369 {
370 struct fetch_insn *code = *pcode;
371 unsigned long param;
372 int deref = FETCH_OP_DEREF;
373 long offset = 0;
374 char *tmp;
375 int ret = 0;
376
377 switch (arg[0]) {
378 case '$':
379 ret = parse_probe_vars(arg + 1, type, code, flags, offs);
380 break;
381
382 case '%': /* named register */
383 if (flags & TPARG_FL_TPOINT) {
384 /* eprobes do not handle registers */
385 trace_probe_log_err(offs, BAD_VAR);
386 break;
387 }
388 ret = regs_query_register_offset(arg + 1);
389 if (ret >= 0) {
390 code->op = FETCH_OP_REG;
391 code->param = (unsigned int)ret;
392 ret = 0;
393 } else
394 trace_probe_log_err(offs, BAD_REG_NAME);
395 break;
396
397 case '@': /* memory, file-offset or symbol */
398 if (isdigit(arg[1])) {
399 ret = kstrtoul(arg + 1, 0, ¶m);
400 if (ret) {
401 trace_probe_log_err(offs, BAD_MEM_ADDR);
402 break;
403 }
404 /* load address */
405 code->op = FETCH_OP_IMM;
406 code->immediate = param;
407 } else if (arg[1] == '+') {
408 /* kprobes don't support file offsets */
409 if (flags & TPARG_FL_KERNEL) {
410 trace_probe_log_err(offs, FILE_ON_KPROBE);
411 return -EINVAL;
412 }
413 ret = kstrtol(arg + 2, 0, &offset);
414 if (ret) {
415 trace_probe_log_err(offs, BAD_FILE_OFFS);
416 break;
417 }
418
419 code->op = FETCH_OP_FOFFS;
420 code->immediate = (unsigned long)offset; // imm64?
421 } else {
422 /* uprobes don't support symbols */
423 if (!(flags & TPARG_FL_KERNEL)) {
424 trace_probe_log_err(offs, SYM_ON_UPROBE);
425 return -EINVAL;
426 }
427 /* Preserve symbol for updating */
428 code->op = FETCH_NOP_SYMBOL;
429 code->data = kstrdup(arg + 1, GFP_KERNEL);
430 if (!code->data)
431 return -ENOMEM;
432 if (++code == end) {
433 trace_probe_log_err(offs, TOO_MANY_OPS);
434 return -EINVAL;
435 }
436 code->op = FETCH_OP_IMM;
437 code->immediate = 0;
438 }
439 /* These are fetching from memory */
440 if (++code == end) {
441 trace_probe_log_err(offs, TOO_MANY_OPS);
442 return -EINVAL;
443 }
444 *pcode = code;
445 code->op = FETCH_OP_DEREF;
446 code->offset = offset;
447 break;
448
449 case '+': /* deref memory */
450 case '-':
451 if (arg[1] == 'u') {
452 deref = FETCH_OP_UDEREF;
453 arg[1] = arg[0];
454 arg++;
455 }
456 if (arg[0] == '+')
457 arg++; /* Skip '+', because kstrtol() rejects it. */
458 tmp = strchr(arg, '(');
459 if (!tmp) {
460 trace_probe_log_err(offs, DEREF_NEED_BRACE);
461 return -EINVAL;
462 }
463 *tmp = '\0';
464 ret = kstrtol(arg, 0, &offset);
465 if (ret) {
466 trace_probe_log_err(offs, BAD_DEREF_OFFS);
467 break;
468 }
469 offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
470 arg = tmp + 1;
471 tmp = strrchr(arg, ')');
472 if (!tmp) {
473 trace_probe_log_err(offs + strlen(arg),
474 DEREF_OPEN_BRACE);
475 return -EINVAL;
476 } else {
477 const struct fetch_type *t2 = find_fetch_type(NULL);
478
479 *tmp = '\0';
480 ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
481 if (ret)
482 break;
483 if (code->op == FETCH_OP_COMM ||
484 code->op == FETCH_OP_DATA) {
485 trace_probe_log_err(offs, COMM_CANT_DEREF);
486 return -EINVAL;
487 }
488 if (++code == end) {
489 trace_probe_log_err(offs, TOO_MANY_OPS);
490 return -EINVAL;
491 }
492 *pcode = code;
493
494 code->op = deref;
495 code->offset = offset;
496 }
497 break;
498 case '\\': /* Immediate value */
499 if (arg[1] == '"') { /* Immediate string */
500 ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
501 if (ret)
502 break;
503 code->op = FETCH_OP_DATA;
504 code->data = tmp;
505 } else {
506 ret = str_to_immediate(arg + 1, &code->immediate);
507 if (ret)
508 trace_probe_log_err(offs + 1, BAD_IMM);
509 else
510 code->op = FETCH_OP_IMM;
511 }
512 break;
513 }
514 if (!ret && code->op == FETCH_OP_NOP) {
515 /* Parsed, but do not find fetch method */
516 trace_probe_log_err(offs, BAD_FETCH_ARG);
517 ret = -EINVAL;
518 }
519 return ret;
520 }
521
522 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
523
524 /* Bitfield type needs to be parsed into a fetch function */
__parse_bitfield_probe_arg(const char * bf,const struct fetch_type * t,struct fetch_insn ** pcode)525 static int __parse_bitfield_probe_arg(const char *bf,
526 const struct fetch_type *t,
527 struct fetch_insn **pcode)
528 {
529 struct fetch_insn *code = *pcode;
530 unsigned long bw, bo;
531 char *tail;
532
533 if (*bf != 'b')
534 return 0;
535
536 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
537
538 if (bw == 0 || *tail != '@')
539 return -EINVAL;
540
541 bf = tail + 1;
542 bo = simple_strtoul(bf, &tail, 0);
543
544 if (tail == bf || *tail != '/')
545 return -EINVAL;
546 code++;
547 if (code->op != FETCH_OP_NOP)
548 return -EINVAL;
549 *pcode = code;
550
551 code->op = FETCH_OP_MOD_BF;
552 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
553 code->rshift = BYTES_TO_BITS(t->size) - bw;
554 code->basesize = t->size;
555
556 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
557 }
558
559 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,unsigned int flags,int offset)560 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
561 struct probe_arg *parg, unsigned int flags, int offset)
562 {
563 struct fetch_insn *code, *scode, *tmp = NULL;
564 char *t, *t2, *t3;
565 char *arg;
566 int ret, len;
567
568 arg = kstrdup(argv, GFP_KERNEL);
569 if (!arg)
570 return -ENOMEM;
571
572 ret = -EINVAL;
573 len = strlen(arg);
574 if (len > MAX_ARGSTR_LEN) {
575 trace_probe_log_err(offset, ARG_TOO_LONG);
576 goto out;
577 } else if (len == 0) {
578 trace_probe_log_err(offset, NO_ARG_BODY);
579 goto out;
580 }
581
582 ret = -ENOMEM;
583 parg->comm = kstrdup(arg, GFP_KERNEL);
584 if (!parg->comm)
585 goto out;
586
587 ret = -EINVAL;
588 t = strchr(arg, ':');
589 if (t) {
590 *t = '\0';
591 t2 = strchr(++t, '[');
592 if (t2) {
593 *t2++ = '\0';
594 t3 = strchr(t2, ']');
595 if (!t3) {
596 offset += t2 + strlen(t2) - arg;
597 trace_probe_log_err(offset,
598 ARRAY_NO_CLOSE);
599 goto out;
600 } else if (t3[1] != '\0') {
601 trace_probe_log_err(offset + t3 + 1 - arg,
602 BAD_ARRAY_SUFFIX);
603 goto out;
604 }
605 *t3 = '\0';
606 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
607 trace_probe_log_err(offset + t2 - arg,
608 BAD_ARRAY_NUM);
609 goto out;
610 }
611 if (parg->count > MAX_ARRAY_LEN) {
612 trace_probe_log_err(offset + t2 - arg,
613 ARRAY_TOO_BIG);
614 goto out;
615 }
616 }
617 }
618
619 /*
620 * Since $comm and immediate string can not be dereferenced,
621 * we can find those by strcmp. But ignore for eprobes.
622 */
623 if (!(flags & TPARG_FL_TPOINT) &&
624 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
625 strncmp(arg, "\\\"", 2) == 0)) {
626 /* The type of $comm must be "string", and not an array. */
627 if (parg->count || (t && strcmp(t, "string")))
628 goto out;
629 parg->type = find_fetch_type("string");
630 } else
631 parg->type = find_fetch_type(t);
632 if (!parg->type) {
633 trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
634 goto out;
635 }
636 parg->offset = *size;
637 *size += parg->type->size * (parg->count ?: 1);
638
639 ret = -ENOMEM;
640 if (parg->count) {
641 len = strlen(parg->type->fmttype) + 6;
642 parg->fmt = kmalloc(len, GFP_KERNEL);
643 if (!parg->fmt)
644 goto out;
645 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
646 parg->count);
647 }
648
649 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
650 if (!code)
651 goto out;
652 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
653
654 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
655 flags, offset);
656 if (ret)
657 goto fail;
658
659 ret = -EINVAL;
660 /* Store operation */
661 if (!strcmp(parg->type->name, "string") ||
662 !strcmp(parg->type->name, "ustring")) {
663 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
664 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
665 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
666 trace_probe_log_err(offset + (t ? (t - arg) : 0),
667 BAD_STRING);
668 goto fail;
669 }
670 if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
671 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
672 parg->count) {
673 /*
674 * IMM, DATA and COMM is pointing actual address, those
675 * must be kept, and if parg->count != 0, this is an
676 * array of string pointers instead of string address
677 * itself.
678 */
679 code++;
680 if (code->op != FETCH_OP_NOP) {
681 trace_probe_log_err(offset, TOO_MANY_OPS);
682 goto fail;
683 }
684 }
685 /* If op == DEREF, replace it with STRING */
686 if (!strcmp(parg->type->name, "ustring") ||
687 code->op == FETCH_OP_UDEREF)
688 code->op = FETCH_OP_ST_USTRING;
689 else
690 code->op = FETCH_OP_ST_STRING;
691 code->size = parg->type->size;
692 parg->dynamic = true;
693 } else if (code->op == FETCH_OP_DEREF) {
694 code->op = FETCH_OP_ST_MEM;
695 code->size = parg->type->size;
696 } else if (code->op == FETCH_OP_UDEREF) {
697 code->op = FETCH_OP_ST_UMEM;
698 code->size = parg->type->size;
699 } else {
700 code++;
701 if (code->op != FETCH_OP_NOP) {
702 trace_probe_log_err(offset, TOO_MANY_OPS);
703 goto fail;
704 }
705 code->op = FETCH_OP_ST_RAW;
706 code->size = parg->type->size;
707 }
708 scode = code;
709 /* Modify operation */
710 if (t != NULL) {
711 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
712 if (ret) {
713 trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
714 goto fail;
715 }
716 }
717 ret = -EINVAL;
718 /* Loop(Array) operation */
719 if (parg->count) {
720 if (scode->op != FETCH_OP_ST_MEM &&
721 scode->op != FETCH_OP_ST_STRING &&
722 scode->op != FETCH_OP_ST_USTRING) {
723 trace_probe_log_err(offset + (t ? (t - arg) : 0),
724 BAD_STRING);
725 goto fail;
726 }
727 code++;
728 if (code->op != FETCH_OP_NOP) {
729 trace_probe_log_err(offset, TOO_MANY_OPS);
730 goto fail;
731 }
732 code->op = FETCH_OP_LP_ARRAY;
733 code->param = parg->count;
734 }
735 code++;
736 code->op = FETCH_OP_END;
737
738 ret = 0;
739 /* Shrink down the code buffer */
740 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
741 if (!parg->code)
742 ret = -ENOMEM;
743 else
744 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
745
746 fail:
747 if (ret) {
748 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
749 if (code->op == FETCH_NOP_SYMBOL ||
750 code->op == FETCH_OP_DATA)
751 kfree(code->data);
752 }
753 kfree(tmp);
754 out:
755 kfree(arg);
756
757 return ret;
758 }
759
760 /* Return 1 if name is reserved or already used by another argument */
traceprobe_conflict_field_name(const char * name,struct probe_arg * args,int narg)761 static int traceprobe_conflict_field_name(const char *name,
762 struct probe_arg *args, int narg)
763 {
764 int i;
765
766 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
767 if (strcmp(reserved_field_names[i], name) == 0)
768 return 1;
769
770 for (i = 0; i < narg; i++)
771 if (strcmp(args[i].name, name) == 0)
772 return 1;
773
774 return 0;
775 }
776
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,unsigned int flags)777 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
778 unsigned int flags)
779 {
780 struct probe_arg *parg = &tp->args[i];
781 const char *body;
782
783 /* Increment count for freeing args in error case */
784 tp->nr_args++;
785
786 body = strchr(arg, '=');
787 if (body) {
788 if (body - arg > MAX_ARG_NAME_LEN) {
789 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
790 return -EINVAL;
791 } else if (body == arg) {
792 trace_probe_log_err(0, NO_ARG_NAME);
793 return -EINVAL;
794 }
795 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
796 body++;
797 } else {
798 /* If argument name is omitted, set "argN" */
799 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
800 body = arg;
801 }
802 if (!parg->name)
803 return -ENOMEM;
804
805 if (!is_good_name(parg->name)) {
806 trace_probe_log_err(0, BAD_ARG_NAME);
807 return -EINVAL;
808 }
809 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
810 trace_probe_log_err(0, USED_ARG_NAME);
811 return -EINVAL;
812 }
813 /* Parse fetch argument */
814 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
815 body - arg);
816 }
817
traceprobe_free_probe_arg(struct probe_arg * arg)818 void traceprobe_free_probe_arg(struct probe_arg *arg)
819 {
820 struct fetch_insn *code = arg->code;
821
822 while (code && code->op != FETCH_OP_END) {
823 if (code->op == FETCH_NOP_SYMBOL ||
824 code->op == FETCH_OP_DATA)
825 kfree(code->data);
826 code++;
827 }
828 kfree(arg->code);
829 kfree(arg->name);
830 kfree(arg->comm);
831 kfree(arg->fmt);
832 }
833
traceprobe_update_arg(struct probe_arg * arg)834 int traceprobe_update_arg(struct probe_arg *arg)
835 {
836 struct fetch_insn *code = arg->code;
837 long offset;
838 char *tmp;
839 char c;
840 int ret = 0;
841
842 while (code && code->op != FETCH_OP_END) {
843 if (code->op == FETCH_NOP_SYMBOL) {
844 if (code[1].op != FETCH_OP_IMM)
845 return -EINVAL;
846
847 tmp = strpbrk(code->data, "+-");
848 if (tmp)
849 c = *tmp;
850 ret = traceprobe_split_symbol_offset(code->data,
851 &offset);
852 if (ret)
853 return ret;
854
855 code[1].immediate =
856 (unsigned long)kallsyms_lookup_name(code->data);
857 if (tmp)
858 *tmp = c;
859 if (!code[1].immediate)
860 return -ENOENT;
861 code[1].immediate += offset;
862 }
863 code++;
864 }
865 return 0;
866 }
867
868 /* When len=0, we just calculate the needed length */
869 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)870 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
871 enum probe_print_type ptype)
872 {
873 struct probe_arg *parg;
874 int i, j;
875 int pos = 0;
876 const char *fmt, *arg;
877
878 switch (ptype) {
879 case PROBE_PRINT_NORMAL:
880 fmt = "(%lx)";
881 arg = ", REC->" FIELD_STRING_IP;
882 break;
883 case PROBE_PRINT_RETURN:
884 fmt = "(%lx <- %lx)";
885 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
886 break;
887 case PROBE_PRINT_EVENT:
888 fmt = "";
889 arg = "";
890 break;
891 default:
892 WARN_ON_ONCE(1);
893 return 0;
894 }
895
896 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
897
898 for (i = 0; i < tp->nr_args; i++) {
899 parg = tp->args + i;
900 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
901 if (parg->count) {
902 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
903 parg->type->fmt);
904 for (j = 1; j < parg->count; j++)
905 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
906 parg->type->fmt);
907 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
908 } else
909 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
910 parg->type->fmt);
911 }
912
913 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
914
915 for (i = 0; i < tp->nr_args; i++) {
916 parg = tp->args + i;
917 if (parg->count) {
918 if ((strcmp(parg->type->name, "string") == 0) ||
919 (strcmp(parg->type->name, "ustring") == 0))
920 fmt = ", __get_str(%s[%d])";
921 else
922 fmt = ", REC->%s[%d]";
923 for (j = 0; j < parg->count; j++)
924 pos += snprintf(buf + pos, LEN_OR_ZERO,
925 fmt, parg->name, j);
926 } else {
927 if ((strcmp(parg->type->name, "string") == 0) ||
928 (strcmp(parg->type->name, "ustring") == 0))
929 fmt = ", __get_str(%s)";
930 else
931 fmt = ", REC->%s";
932 pos += snprintf(buf + pos, LEN_OR_ZERO,
933 fmt, parg->name);
934 }
935 }
936
937 /* return the length of print_fmt */
938 return pos;
939 }
940 #undef LEN_OR_ZERO
941
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)942 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
943 {
944 struct trace_event_call *call = trace_probe_event_call(tp);
945 int len;
946 char *print_fmt;
947
948 /* First: called with 0 length to calculate the needed length */
949 len = __set_print_fmt(tp, NULL, 0, ptype);
950 print_fmt = kmalloc(len + 1, GFP_KERNEL);
951 if (!print_fmt)
952 return -ENOMEM;
953
954 /* Second: actually write the @print_fmt */
955 __set_print_fmt(tp, print_fmt, len + 1, ptype);
956 call->print_fmt = print_fmt;
957
958 return 0;
959 }
960
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)961 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
962 size_t offset, struct trace_probe *tp)
963 {
964 int ret, i;
965
966 /* Set argument names as fields */
967 for (i = 0; i < tp->nr_args; i++) {
968 struct probe_arg *parg = &tp->args[i];
969 const char *fmt = parg->type->fmttype;
970 int size = parg->type->size;
971
972 if (parg->fmt)
973 fmt = parg->fmt;
974 if (parg->count)
975 size *= parg->count;
976 ret = trace_define_field(event_call, fmt, parg->name,
977 offset + parg->offset, size,
978 parg->type->is_signed,
979 FILTER_OTHER);
980 if (ret)
981 return ret;
982 }
983 return 0;
984 }
985
trace_probe_event_free(struct trace_probe_event * tpe)986 static void trace_probe_event_free(struct trace_probe_event *tpe)
987 {
988 kfree(tpe->class.system);
989 kfree(tpe->call.name);
990 kfree(tpe->call.print_fmt);
991 kfree(tpe);
992 }
993
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)994 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
995 {
996 if (trace_probe_has_sibling(tp))
997 return -EBUSY;
998
999 list_del_init(&tp->list);
1000 trace_probe_event_free(tp->event);
1001
1002 tp->event = to->event;
1003 list_add_tail(&tp->list, trace_probe_probe_list(to));
1004
1005 return 0;
1006 }
1007
trace_probe_unlink(struct trace_probe * tp)1008 void trace_probe_unlink(struct trace_probe *tp)
1009 {
1010 list_del_init(&tp->list);
1011 if (list_empty(trace_probe_probe_list(tp)))
1012 trace_probe_event_free(tp->event);
1013 tp->event = NULL;
1014 }
1015
trace_probe_cleanup(struct trace_probe * tp)1016 void trace_probe_cleanup(struct trace_probe *tp)
1017 {
1018 int i;
1019
1020 for (i = 0; i < tp->nr_args; i++)
1021 traceprobe_free_probe_arg(&tp->args[i]);
1022
1023 if (tp->event)
1024 trace_probe_unlink(tp);
1025 }
1026
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter)1027 int trace_probe_init(struct trace_probe *tp, const char *event,
1028 const char *group, bool alloc_filter)
1029 {
1030 struct trace_event_call *call;
1031 size_t size = sizeof(struct trace_probe_event);
1032 int ret = 0;
1033
1034 if (!event || !group)
1035 return -EINVAL;
1036
1037 if (alloc_filter)
1038 size += sizeof(struct trace_uprobe_filter);
1039
1040 tp->event = kzalloc(size, GFP_KERNEL);
1041 if (!tp->event)
1042 return -ENOMEM;
1043
1044 INIT_LIST_HEAD(&tp->event->files);
1045 INIT_LIST_HEAD(&tp->event->class.fields);
1046 INIT_LIST_HEAD(&tp->event->probes);
1047 INIT_LIST_HEAD(&tp->list);
1048 list_add(&tp->list, &tp->event->probes);
1049
1050 call = trace_probe_event_call(tp);
1051 call->class = &tp->event->class;
1052 call->name = kstrdup(event, GFP_KERNEL);
1053 if (!call->name) {
1054 ret = -ENOMEM;
1055 goto error;
1056 }
1057
1058 tp->event->class.system = kstrdup(group, GFP_KERNEL);
1059 if (!tp->event->class.system) {
1060 ret = -ENOMEM;
1061 goto error;
1062 }
1063
1064 return 0;
1065
1066 error:
1067 trace_probe_cleanup(tp);
1068 return ret;
1069 }
1070
1071 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)1072 find_trace_event_call(const char *system, const char *event_name)
1073 {
1074 struct trace_event_call *tp_event;
1075 const char *name;
1076
1077 list_for_each_entry(tp_event, &ftrace_events, list) {
1078 if (!tp_event->class->system ||
1079 strcmp(system, tp_event->class->system))
1080 continue;
1081 name = trace_event_name(tp_event);
1082 if (!name || strcmp(event_name, name))
1083 continue;
1084 return tp_event;
1085 }
1086
1087 return NULL;
1088 }
1089
trace_probe_register_event_call(struct trace_probe * tp)1090 int trace_probe_register_event_call(struct trace_probe *tp)
1091 {
1092 struct trace_event_call *call = trace_probe_event_call(tp);
1093 int ret;
1094
1095 lockdep_assert_held(&event_mutex);
1096
1097 if (find_trace_event_call(trace_probe_group_name(tp),
1098 trace_probe_name(tp)))
1099 return -EEXIST;
1100
1101 ret = register_trace_event(&call->event);
1102 if (!ret)
1103 return -ENODEV;
1104
1105 ret = trace_add_event_call(call);
1106 if (ret)
1107 unregister_trace_event(&call->event);
1108
1109 return ret;
1110 }
1111
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)1112 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1113 {
1114 struct event_file_link *link;
1115
1116 link = kmalloc(sizeof(*link), GFP_KERNEL);
1117 if (!link)
1118 return -ENOMEM;
1119
1120 link->file = file;
1121 INIT_LIST_HEAD(&link->list);
1122 list_add_tail_rcu(&link->list, &tp->event->files);
1123 trace_probe_set_flag(tp, TP_FLAG_TRACE);
1124 return 0;
1125 }
1126
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)1127 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1128 struct trace_event_file *file)
1129 {
1130 struct event_file_link *link;
1131
1132 trace_probe_for_each_link(link, tp) {
1133 if (link->file == file)
1134 return link;
1135 }
1136
1137 return NULL;
1138 }
1139
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)1140 int trace_probe_remove_file(struct trace_probe *tp,
1141 struct trace_event_file *file)
1142 {
1143 struct event_file_link *link;
1144
1145 link = trace_probe_get_file_link(tp, file);
1146 if (!link)
1147 return -ENOENT;
1148
1149 list_del_rcu(&link->list);
1150 kvfree_rcu(link);
1151
1152 if (list_empty(&tp->event->files))
1153 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1154
1155 return 0;
1156 }
1157
1158 /*
1159 * Return the smallest index of different type argument (start from 1).
1160 * If all argument types and name are same, return 0.
1161 */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)1162 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1163 {
1164 int i;
1165
1166 /* In case of more arguments */
1167 if (a->nr_args < b->nr_args)
1168 return a->nr_args + 1;
1169 if (a->nr_args > b->nr_args)
1170 return b->nr_args + 1;
1171
1172 for (i = 0; i < a->nr_args; i++) {
1173 if ((b->nr_args <= i) ||
1174 ((a->args[i].type != b->args[i].type) ||
1175 (a->args[i].count != b->args[i].count) ||
1176 strcmp(a->args[i].name, b->args[i].name)))
1177 return i + 1;
1178 }
1179
1180 return 0;
1181 }
1182
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)1183 bool trace_probe_match_command_args(struct trace_probe *tp,
1184 int argc, const char **argv)
1185 {
1186 char buf[MAX_ARGSTR_LEN + 1];
1187 int i;
1188
1189 if (tp->nr_args < argc)
1190 return false;
1191
1192 for (i = 0; i < argc; i++) {
1193 snprintf(buf, sizeof(buf), "%s=%s",
1194 tp->args[i].name, tp->args[i].comm);
1195 if (strcmp(buf, argv[i]))
1196 return false;
1197 }
1198 return true;
1199 }
1200
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))1201 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1202 {
1203 int argc = 0, ret = 0;
1204 char **argv;
1205
1206 argv = argv_split(GFP_KERNEL, raw_command, &argc);
1207 if (!argv)
1208 return -ENOMEM;
1209
1210 if (argc)
1211 ret = createfn(argc, (const char **)argv);
1212
1213 argv_free(argv);
1214
1215 return ret;
1216 }
1217