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 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
54
PRINT_TYPE_FUNC_NAME(symbol)55 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
56 {
57 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
58 return !trace_seq_has_overflowed(s);
59 }
60 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
61
62 /* Print type function for string type */
PRINT_TYPE_FUNC_NAME(string)63 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
64 {
65 int len = *(u32 *)data >> 16;
66
67 if (!len)
68 trace_seq_puts(s, "(fault)");
69 else
70 trace_seq_printf(s, "\"%s\"",
71 (const char *)get_loc_data(data, ent));
72 return !trace_seq_has_overflowed(s);
73 }
74
75 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
76
77 /* Fetch type information table */
78 static const struct fetch_type probe_fetch_types[] = {
79 /* Special types */
80 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
81 "__data_loc char[]"),
82 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
83 "__data_loc char[]"),
84 __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
85 "__data_loc char[]"),
86 /* Basic types */
87 ASSIGN_FETCH_TYPE(u8, u8, 0),
88 ASSIGN_FETCH_TYPE(u16, u16, 0),
89 ASSIGN_FETCH_TYPE(u32, u32, 0),
90 ASSIGN_FETCH_TYPE(u64, u64, 0),
91 ASSIGN_FETCH_TYPE(s8, u8, 1),
92 ASSIGN_FETCH_TYPE(s16, u16, 1),
93 ASSIGN_FETCH_TYPE(s32, u32, 1),
94 ASSIGN_FETCH_TYPE(s64, u64, 1),
95 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
96 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
97 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
98 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
99 ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0),
100 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
101
102 ASSIGN_FETCH_TYPE_END
103 };
104
find_fetch_type(const char * type,unsigned long flags)105 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
106 {
107 int i;
108
109 /* Reject the symbol/symstr for uprobes */
110 if (type && (flags & TPARG_FL_USER) &&
111 (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
112 return NULL;
113
114 if (!type)
115 type = DEFAULT_FETCH_TYPE_STR;
116
117 /* Special case: bitfield */
118 if (*type == 'b') {
119 unsigned long bs;
120
121 type = strchr(type, '/');
122 if (!type)
123 goto fail;
124
125 type++;
126 if (kstrtoul(type, 0, &bs))
127 goto fail;
128
129 switch (bs) {
130 case 8:
131 return find_fetch_type("u8", flags);
132 case 16:
133 return find_fetch_type("u16", flags);
134 case 32:
135 return find_fetch_type("u32", flags);
136 case 64:
137 return find_fetch_type("u64", flags);
138 default:
139 goto fail;
140 }
141 }
142
143 for (i = 0; probe_fetch_types[i].name; i++) {
144 if (strcmp(type, probe_fetch_types[i].name) == 0)
145 return &probe_fetch_types[i];
146 }
147
148 fail:
149 return NULL;
150 }
151
152 static struct trace_probe_log trace_probe_log;
153
trace_probe_log_init(const char * subsystem,int argc,const char ** argv)154 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
155 {
156 trace_probe_log.subsystem = subsystem;
157 trace_probe_log.argc = argc;
158 trace_probe_log.argv = argv;
159 trace_probe_log.index = 0;
160 }
161
trace_probe_log_clear(void)162 void trace_probe_log_clear(void)
163 {
164 memset(&trace_probe_log, 0, sizeof(trace_probe_log));
165 }
166
trace_probe_log_set_index(int index)167 void trace_probe_log_set_index(int index)
168 {
169 trace_probe_log.index = index;
170 }
171
__trace_probe_log_err(int offset,int err_type)172 void __trace_probe_log_err(int offset, int err_type)
173 {
174 char *command, *p;
175 int i, len = 0, pos = 0;
176
177 if (!trace_probe_log.argv)
178 return;
179
180 /* Recalculate the length and allocate buffer */
181 for (i = 0; i < trace_probe_log.argc; i++) {
182 if (i == trace_probe_log.index)
183 pos = len;
184 len += strlen(trace_probe_log.argv[i]) + 1;
185 }
186 command = kzalloc(len, GFP_KERNEL);
187 if (!command)
188 return;
189
190 if (trace_probe_log.index >= trace_probe_log.argc) {
191 /**
192 * Set the error position is next to the last arg + space.
193 * Note that len includes the terminal null and the cursor
194 * appears at pos + 1.
195 */
196 pos = len;
197 offset = 0;
198 }
199
200 /* And make a command string from argv array */
201 p = command;
202 for (i = 0; i < trace_probe_log.argc; i++) {
203 len = strlen(trace_probe_log.argv[i]);
204 strcpy(p, trace_probe_log.argv[i]);
205 p[len] = ' ';
206 p += len + 1;
207 }
208 *(p - 1) = '\0';
209
210 tracing_log_err(NULL, trace_probe_log.subsystem, command,
211 trace_probe_err_text, err_type, pos + offset);
212
213 kfree(command);
214 }
215
216 /* Split symbol and offset. */
traceprobe_split_symbol_offset(char * symbol,long * offset)217 int traceprobe_split_symbol_offset(char *symbol, long *offset)
218 {
219 char *tmp;
220 int ret;
221
222 if (!offset)
223 return -EINVAL;
224
225 tmp = strpbrk(symbol, "+-");
226 if (tmp) {
227 ret = kstrtol(tmp, 0, offset);
228 if (ret)
229 return ret;
230 *tmp = '\0';
231 } else
232 *offset = 0;
233
234 return 0;
235 }
236
237 /* @buf must has MAX_EVENT_NAME_LEN size */
traceprobe_parse_event_name(const char ** pevent,const char ** pgroup,char * buf,int offset)238 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
239 char *buf, int offset)
240 {
241 const char *slash, *event = *pevent;
242 int len;
243
244 slash = strchr(event, '/');
245 if (!slash)
246 slash = strchr(event, '.');
247
248 if (slash) {
249 if (slash == event) {
250 trace_probe_log_err(offset, NO_GROUP_NAME);
251 return -EINVAL;
252 }
253 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
254 trace_probe_log_err(offset, GROUP_TOO_LONG);
255 return -EINVAL;
256 }
257 strlcpy(buf, event, slash - event + 1);
258 if (!is_good_system_name(buf)) {
259 trace_probe_log_err(offset, BAD_GROUP_NAME);
260 return -EINVAL;
261 }
262 *pgroup = buf;
263 *pevent = slash + 1;
264 offset += slash - event + 1;
265 event = *pevent;
266 }
267 len = strlen(event);
268 if (len == 0) {
269 if (slash) {
270 *pevent = NULL;
271 return 0;
272 }
273 trace_probe_log_err(offset, NO_EVENT_NAME);
274 return -EINVAL;
275 } else if (len > MAX_EVENT_NAME_LEN) {
276 trace_probe_log_err(offset, EVENT_TOO_LONG);
277 return -EINVAL;
278 }
279 if (!is_good_name(event)) {
280 trace_probe_log_err(offset, BAD_EVENT_NAME);
281 return -EINVAL;
282 }
283 return 0;
284 }
285
286 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
287
parse_probe_vars(char * arg,const struct fetch_type * t,struct fetch_insn * code,unsigned int flags,int offs)288 static int parse_probe_vars(char *arg, const struct fetch_type *t,
289 struct fetch_insn *code, unsigned int flags, int offs)
290 {
291 unsigned long param;
292 int ret = 0;
293 int len;
294
295 if (flags & TPARG_FL_TPOINT) {
296 if (code->data)
297 return -EFAULT;
298 code->data = kstrdup(arg, GFP_KERNEL);
299 if (!code->data)
300 return -ENOMEM;
301 code->op = FETCH_OP_TP_ARG;
302 } else if (strcmp(arg, "retval") == 0) {
303 if (flags & TPARG_FL_RETURN) {
304 code->op = FETCH_OP_RETVAL;
305 } else {
306 trace_probe_log_err(offs, RETVAL_ON_PROBE);
307 ret = -EINVAL;
308 }
309 } else if ((len = str_has_prefix(arg, "stack"))) {
310 if (arg[len] == '\0') {
311 code->op = FETCH_OP_STACKP;
312 } else if (isdigit(arg[len])) {
313 ret = kstrtoul(arg + len, 10, ¶m);
314 if (ret) {
315 goto inval_var;
316 } else if ((flags & TPARG_FL_KERNEL) &&
317 param > PARAM_MAX_STACK) {
318 trace_probe_log_err(offs, BAD_STACK_NUM);
319 ret = -EINVAL;
320 } else {
321 code->op = FETCH_OP_STACK;
322 code->param = (unsigned int)param;
323 }
324 } else
325 goto inval_var;
326 } else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
327 code->op = FETCH_OP_COMM;
328 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
329 } else if (((flags & TPARG_FL_MASK) ==
330 (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
331 (len = str_has_prefix(arg, "arg"))) {
332 ret = kstrtoul(arg + len, 10, ¶m);
333 if (ret) {
334 goto inval_var;
335 } else if (!param || param > PARAM_MAX_STACK) {
336 trace_probe_log_err(offs, BAD_ARG_NUM);
337 return -EINVAL;
338 }
339 code->op = FETCH_OP_ARG;
340 code->param = (unsigned int)param - 1;
341 #endif
342 } else
343 goto inval_var;
344
345 return ret;
346
347 inval_var:
348 trace_probe_log_err(offs, BAD_VAR);
349 return -EINVAL;
350 }
351
str_to_immediate(char * str,unsigned long * imm)352 static int str_to_immediate(char *str, unsigned long *imm)
353 {
354 if (isdigit(str[0]))
355 return kstrtoul(str, 0, imm);
356 else if (str[0] == '-')
357 return kstrtol(str, 0, (long *)imm);
358 else if (str[0] == '+')
359 return kstrtol(str + 1, 0, (long *)imm);
360 return -EINVAL;
361 }
362
__parse_imm_string(char * str,char ** pbuf,int offs)363 static int __parse_imm_string(char *str, char **pbuf, int offs)
364 {
365 size_t len = strlen(str);
366
367 if (str[len - 1] != '"') {
368 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
369 return -EINVAL;
370 }
371 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
372 if (!*pbuf)
373 return -ENOMEM;
374 return 0;
375 }
376
377 /* Recursive argument parser */
378 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)379 parse_probe_arg(char *arg, const struct fetch_type *type,
380 struct fetch_insn **pcode, struct fetch_insn *end,
381 unsigned int flags, int offs)
382 {
383 struct fetch_insn *code = *pcode;
384 unsigned long param;
385 int deref = FETCH_OP_DEREF;
386 long offset = 0;
387 char *tmp;
388 int ret = 0;
389
390 switch (arg[0]) {
391 case '$':
392 ret = parse_probe_vars(arg + 1, type, code, flags, offs);
393 break;
394
395 case '%': /* named register */
396 if (flags & TPARG_FL_TPOINT) {
397 /* eprobes do not handle registers */
398 trace_probe_log_err(offs, BAD_VAR);
399 break;
400 }
401 ret = regs_query_register_offset(arg + 1);
402 if (ret >= 0) {
403 code->op = FETCH_OP_REG;
404 code->param = (unsigned int)ret;
405 ret = 0;
406 } else
407 trace_probe_log_err(offs, BAD_REG_NAME);
408 break;
409
410 case '@': /* memory, file-offset or symbol */
411 if (isdigit(arg[1])) {
412 ret = kstrtoul(arg + 1, 0, ¶m);
413 if (ret) {
414 trace_probe_log_err(offs, BAD_MEM_ADDR);
415 break;
416 }
417 /* load address */
418 code->op = FETCH_OP_IMM;
419 code->immediate = param;
420 } else if (arg[1] == '+') {
421 /* kprobes don't support file offsets */
422 if (flags & TPARG_FL_KERNEL) {
423 trace_probe_log_err(offs, FILE_ON_KPROBE);
424 return -EINVAL;
425 }
426 ret = kstrtol(arg + 2, 0, &offset);
427 if (ret) {
428 trace_probe_log_err(offs, BAD_FILE_OFFS);
429 break;
430 }
431
432 code->op = FETCH_OP_FOFFS;
433 code->immediate = (unsigned long)offset; // imm64?
434 } else {
435 /* uprobes don't support symbols */
436 if (!(flags & TPARG_FL_KERNEL)) {
437 trace_probe_log_err(offs, SYM_ON_UPROBE);
438 return -EINVAL;
439 }
440 /* Preserve symbol for updating */
441 code->op = FETCH_NOP_SYMBOL;
442 code->data = kstrdup(arg + 1, GFP_KERNEL);
443 if (!code->data)
444 return -ENOMEM;
445 if (++code == end) {
446 trace_probe_log_err(offs, TOO_MANY_OPS);
447 return -EINVAL;
448 }
449 code->op = FETCH_OP_IMM;
450 code->immediate = 0;
451 }
452 /* These are fetching from memory */
453 if (++code == end) {
454 trace_probe_log_err(offs, TOO_MANY_OPS);
455 return -EINVAL;
456 }
457 *pcode = code;
458 code->op = FETCH_OP_DEREF;
459 code->offset = offset;
460 break;
461
462 case '+': /* deref memory */
463 case '-':
464 if (arg[1] == 'u') {
465 deref = FETCH_OP_UDEREF;
466 arg[1] = arg[0];
467 arg++;
468 }
469 if (arg[0] == '+')
470 arg++; /* Skip '+', because kstrtol() rejects it. */
471 tmp = strchr(arg, '(');
472 if (!tmp) {
473 trace_probe_log_err(offs, DEREF_NEED_BRACE);
474 return -EINVAL;
475 }
476 *tmp = '\0';
477 ret = kstrtol(arg, 0, &offset);
478 if (ret) {
479 trace_probe_log_err(offs, BAD_DEREF_OFFS);
480 break;
481 }
482 offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
483 arg = tmp + 1;
484 tmp = strrchr(arg, ')');
485 if (!tmp) {
486 trace_probe_log_err(offs + strlen(arg),
487 DEREF_OPEN_BRACE);
488 return -EINVAL;
489 } else {
490 const struct fetch_type *t2 = find_fetch_type(NULL, flags);
491
492 *tmp = '\0';
493 ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
494 if (ret)
495 break;
496 if (code->op == FETCH_OP_COMM ||
497 code->op == FETCH_OP_DATA) {
498 trace_probe_log_err(offs, COMM_CANT_DEREF);
499 return -EINVAL;
500 }
501 if (++code == end) {
502 trace_probe_log_err(offs, TOO_MANY_OPS);
503 return -EINVAL;
504 }
505 *pcode = code;
506
507 code->op = deref;
508 code->offset = offset;
509 }
510 break;
511 case '\\': /* Immediate value */
512 if (arg[1] == '"') { /* Immediate string */
513 ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
514 if (ret)
515 break;
516 code->op = FETCH_OP_DATA;
517 code->data = tmp;
518 } else {
519 ret = str_to_immediate(arg + 1, &code->immediate);
520 if (ret)
521 trace_probe_log_err(offs + 1, BAD_IMM);
522 else
523 code->op = FETCH_OP_IMM;
524 }
525 break;
526 }
527 if (!ret && code->op == FETCH_OP_NOP) {
528 /* Parsed, but do not find fetch method */
529 trace_probe_log_err(offs, BAD_FETCH_ARG);
530 ret = -EINVAL;
531 }
532 return ret;
533 }
534
535 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
536
537 /* 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)538 static int __parse_bitfield_probe_arg(const char *bf,
539 const struct fetch_type *t,
540 struct fetch_insn **pcode)
541 {
542 struct fetch_insn *code = *pcode;
543 unsigned long bw, bo;
544 char *tail;
545
546 if (*bf != 'b')
547 return 0;
548
549 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
550
551 if (bw == 0 || *tail != '@')
552 return -EINVAL;
553
554 bf = tail + 1;
555 bo = simple_strtoul(bf, &tail, 0);
556
557 if (tail == bf || *tail != '/')
558 return -EINVAL;
559 code++;
560 if (code->op != FETCH_OP_NOP)
561 return -EINVAL;
562 *pcode = code;
563
564 code->op = FETCH_OP_MOD_BF;
565 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
566 code->rshift = BYTES_TO_BITS(t->size) - bw;
567 code->basesize = t->size;
568
569 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
570 }
571
572 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,unsigned int flags,int offset)573 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
574 struct probe_arg *parg, unsigned int flags, int offset)
575 {
576 struct fetch_insn *code, *scode, *tmp = NULL;
577 char *t, *t2, *t3;
578 char *arg;
579 int ret, len;
580
581 arg = kstrdup(argv, GFP_KERNEL);
582 if (!arg)
583 return -ENOMEM;
584
585 ret = -EINVAL;
586 len = strlen(arg);
587 if (len > MAX_ARGSTR_LEN) {
588 trace_probe_log_err(offset, ARG_TOO_LONG);
589 goto out;
590 } else if (len == 0) {
591 trace_probe_log_err(offset, NO_ARG_BODY);
592 goto out;
593 }
594
595 ret = -ENOMEM;
596 parg->comm = kstrdup(arg, GFP_KERNEL);
597 if (!parg->comm)
598 goto out;
599
600 ret = -EINVAL;
601 t = strchr(arg, ':');
602 if (t) {
603 *t = '\0';
604 t2 = strchr(++t, '[');
605 if (t2) {
606 *t2++ = '\0';
607 t3 = strchr(t2, ']');
608 if (!t3) {
609 offset += t2 + strlen(t2) - arg;
610 trace_probe_log_err(offset,
611 ARRAY_NO_CLOSE);
612 goto out;
613 } else if (t3[1] != '\0') {
614 trace_probe_log_err(offset + t3 + 1 - arg,
615 BAD_ARRAY_SUFFIX);
616 goto out;
617 }
618 *t3 = '\0';
619 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
620 trace_probe_log_err(offset + t2 - arg,
621 BAD_ARRAY_NUM);
622 goto out;
623 }
624 if (parg->count > MAX_ARRAY_LEN) {
625 trace_probe_log_err(offset + t2 - arg,
626 ARRAY_TOO_BIG);
627 goto out;
628 }
629 }
630 }
631
632 /*
633 * Since $comm and immediate string can not be dereferenced,
634 * we can find those by strcmp. But ignore for eprobes.
635 */
636 if (!(flags & TPARG_FL_TPOINT) &&
637 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
638 strncmp(arg, "\\\"", 2) == 0)) {
639 /* The type of $comm must be "string", and not an array. */
640 if (parg->count || (t && strcmp(t, "string")))
641 goto out;
642 parg->type = find_fetch_type("string", flags);
643 } else
644 parg->type = find_fetch_type(t, flags);
645 if (!parg->type) {
646 trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
647 goto out;
648 }
649 parg->offset = *size;
650 *size += parg->type->size * (parg->count ?: 1);
651
652 ret = -ENOMEM;
653 if (parg->count) {
654 len = strlen(parg->type->fmttype) + 6;
655 parg->fmt = kmalloc(len, GFP_KERNEL);
656 if (!parg->fmt)
657 goto out;
658 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
659 parg->count);
660 }
661
662 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
663 if (!code)
664 goto out;
665 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
666
667 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
668 flags, offset);
669 if (ret)
670 goto fail;
671
672 ret = -EINVAL;
673 /* Store operation */
674 if (parg->type->is_string) {
675 if (!strcmp(parg->type->name, "symstr")) {
676 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
677 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
678 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
679 trace_probe_log_err(offset + (t ? (t - arg) : 0),
680 BAD_SYMSTRING);
681 goto fail;
682 }
683 } else {
684 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
685 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
686 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
687 trace_probe_log_err(offset + (t ? (t - arg) : 0),
688 BAD_STRING);
689 goto fail;
690 }
691 }
692 if (!strcmp(parg->type->name, "symstr") ||
693 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
694 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
695 parg->count) {
696 /*
697 * IMM, DATA and COMM is pointing actual address, those
698 * must be kept, and if parg->count != 0, this is an
699 * array of string pointers instead of string address
700 * itself.
701 * For the symstr, it doesn't need to dereference, thus
702 * it just get the value.
703 */
704 code++;
705 if (code->op != FETCH_OP_NOP) {
706 trace_probe_log_err(offset, TOO_MANY_OPS);
707 goto fail;
708 }
709 }
710 /* If op == DEREF, replace it with STRING */
711 if (!strcmp(parg->type->name, "ustring") ||
712 code->op == FETCH_OP_UDEREF)
713 code->op = FETCH_OP_ST_USTRING;
714 else if (!strcmp(parg->type->name, "symstr"))
715 code->op = FETCH_OP_ST_SYMSTR;
716 else
717 code->op = FETCH_OP_ST_STRING;
718 code->size = parg->type->size;
719 parg->dynamic = true;
720 } else if (code->op == FETCH_OP_DEREF) {
721 code->op = FETCH_OP_ST_MEM;
722 code->size = parg->type->size;
723 } else if (code->op == FETCH_OP_UDEREF) {
724 code->op = FETCH_OP_ST_UMEM;
725 code->size = parg->type->size;
726 } else {
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_ST_RAW;
733 code->size = parg->type->size;
734 }
735 scode = code;
736 /* Modify operation */
737 if (t != NULL) {
738 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
739 if (ret) {
740 trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
741 goto fail;
742 }
743 }
744 ret = -EINVAL;
745 /* Loop(Array) operation */
746 if (parg->count) {
747 if (scode->op != FETCH_OP_ST_MEM &&
748 scode->op != FETCH_OP_ST_STRING &&
749 scode->op != FETCH_OP_ST_USTRING) {
750 trace_probe_log_err(offset + (t ? (t - arg) : 0),
751 BAD_STRING);
752 goto fail;
753 }
754 code++;
755 if (code->op != FETCH_OP_NOP) {
756 trace_probe_log_err(offset, TOO_MANY_OPS);
757 goto fail;
758 }
759 code->op = FETCH_OP_LP_ARRAY;
760 code->param = parg->count;
761 }
762 code++;
763 code->op = FETCH_OP_END;
764
765 ret = 0;
766 /* Shrink down the code buffer */
767 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
768 if (!parg->code)
769 ret = -ENOMEM;
770 else
771 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
772
773 fail:
774 if (ret) {
775 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
776 if (code->op == FETCH_NOP_SYMBOL ||
777 code->op == FETCH_OP_DATA)
778 kfree(code->data);
779 }
780 kfree(tmp);
781 out:
782 kfree(arg);
783
784 return ret;
785 }
786
787 /* 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)788 static int traceprobe_conflict_field_name(const char *name,
789 struct probe_arg *args, int narg)
790 {
791 int i;
792
793 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
794 if (strcmp(reserved_field_names[i], name) == 0)
795 return 1;
796
797 for (i = 0; i < narg; i++)
798 if (strcmp(args[i].name, name) == 0)
799 return 1;
800
801 return 0;
802 }
803
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,unsigned int flags)804 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
805 unsigned int flags)
806 {
807 struct probe_arg *parg = &tp->args[i];
808 const char *body;
809
810 /* Increment count for freeing args in error case */
811 tp->nr_args++;
812
813 body = strchr(arg, '=');
814 if (body) {
815 if (body - arg > MAX_ARG_NAME_LEN) {
816 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
817 return -EINVAL;
818 } else if (body == arg) {
819 trace_probe_log_err(0, NO_ARG_NAME);
820 return -EINVAL;
821 }
822 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
823 body++;
824 } else {
825 /* If argument name is omitted, set "argN" */
826 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
827 body = arg;
828 }
829 if (!parg->name)
830 return -ENOMEM;
831
832 if (!is_good_name(parg->name)) {
833 trace_probe_log_err(0, BAD_ARG_NAME);
834 return -EINVAL;
835 }
836 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
837 trace_probe_log_err(0, USED_ARG_NAME);
838 return -EINVAL;
839 }
840 /* Parse fetch argument */
841 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
842 body - arg);
843 }
844
traceprobe_free_probe_arg(struct probe_arg * arg)845 void traceprobe_free_probe_arg(struct probe_arg *arg)
846 {
847 struct fetch_insn *code = arg->code;
848
849 while (code && code->op != FETCH_OP_END) {
850 if (code->op == FETCH_NOP_SYMBOL ||
851 code->op == FETCH_OP_DATA)
852 kfree(code->data);
853 code++;
854 }
855 kfree(arg->code);
856 kfree(arg->name);
857 kfree(arg->comm);
858 kfree(arg->fmt);
859 }
860
traceprobe_update_arg(struct probe_arg * arg)861 int traceprobe_update_arg(struct probe_arg *arg)
862 {
863 struct fetch_insn *code = arg->code;
864 long offset;
865 char *tmp;
866 char c;
867 int ret = 0;
868
869 while (code && code->op != FETCH_OP_END) {
870 if (code->op == FETCH_NOP_SYMBOL) {
871 if (code[1].op != FETCH_OP_IMM)
872 return -EINVAL;
873
874 tmp = strpbrk(code->data, "+-");
875 if (tmp)
876 c = *tmp;
877 ret = traceprobe_split_symbol_offset(code->data,
878 &offset);
879 if (ret)
880 return ret;
881
882 code[1].immediate =
883 (unsigned long)kallsyms_lookup_name(code->data);
884 if (tmp)
885 *tmp = c;
886 if (!code[1].immediate)
887 return -ENOENT;
888 code[1].immediate += offset;
889 }
890 code++;
891 }
892 return 0;
893 }
894
895 /* When len=0, we just calculate the needed length */
896 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)897 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
898 enum probe_print_type ptype)
899 {
900 struct probe_arg *parg;
901 int i, j;
902 int pos = 0;
903 const char *fmt, *arg;
904
905 switch (ptype) {
906 case PROBE_PRINT_NORMAL:
907 fmt = "(%lx)";
908 arg = ", REC->" FIELD_STRING_IP;
909 break;
910 case PROBE_PRINT_RETURN:
911 fmt = "(%lx <- %lx)";
912 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
913 break;
914 case PROBE_PRINT_EVENT:
915 fmt = "";
916 arg = "";
917 break;
918 default:
919 WARN_ON_ONCE(1);
920 return 0;
921 }
922
923 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
924
925 for (i = 0; i < tp->nr_args; i++) {
926 parg = tp->args + i;
927 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
928 if (parg->count) {
929 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
930 parg->type->fmt);
931 for (j = 1; j < parg->count; j++)
932 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
933 parg->type->fmt);
934 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
935 } else
936 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
937 parg->type->fmt);
938 }
939
940 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
941
942 for (i = 0; i < tp->nr_args; i++) {
943 parg = tp->args + i;
944 if (parg->count) {
945 if (parg->type->is_string)
946 fmt = ", __get_str(%s[%d])";
947 else
948 fmt = ", REC->%s[%d]";
949 for (j = 0; j < parg->count; j++)
950 pos += snprintf(buf + pos, LEN_OR_ZERO,
951 fmt, parg->name, j);
952 } else {
953 if (parg->type->is_string)
954 fmt = ", __get_str(%s)";
955 else
956 fmt = ", REC->%s";
957 pos += snprintf(buf + pos, LEN_OR_ZERO,
958 fmt, parg->name);
959 }
960 }
961
962 /* return the length of print_fmt */
963 return pos;
964 }
965 #undef LEN_OR_ZERO
966
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)967 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
968 {
969 struct trace_event_call *call = trace_probe_event_call(tp);
970 int len;
971 char *print_fmt;
972
973 /* First: called with 0 length to calculate the needed length */
974 len = __set_print_fmt(tp, NULL, 0, ptype);
975 print_fmt = kmalloc(len + 1, GFP_KERNEL);
976 if (!print_fmt)
977 return -ENOMEM;
978
979 /* Second: actually write the @print_fmt */
980 __set_print_fmt(tp, print_fmt, len + 1, ptype);
981 call->print_fmt = print_fmt;
982
983 return 0;
984 }
985
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)986 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
987 size_t offset, struct trace_probe *tp)
988 {
989 int ret, i;
990
991 /* Set argument names as fields */
992 for (i = 0; i < tp->nr_args; i++) {
993 struct probe_arg *parg = &tp->args[i];
994 const char *fmt = parg->type->fmttype;
995 int size = parg->type->size;
996
997 if (parg->fmt)
998 fmt = parg->fmt;
999 if (parg->count)
1000 size *= parg->count;
1001 ret = trace_define_field(event_call, fmt, parg->name,
1002 offset + parg->offset, size,
1003 parg->type->is_signed,
1004 FILTER_OTHER);
1005 if (ret)
1006 return ret;
1007 }
1008 return 0;
1009 }
1010
trace_probe_event_free(struct trace_probe_event * tpe)1011 static void trace_probe_event_free(struct trace_probe_event *tpe)
1012 {
1013 kfree(tpe->class.system);
1014 kfree(tpe->call.name);
1015 kfree(tpe->call.print_fmt);
1016 kfree(tpe);
1017 }
1018
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)1019 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1020 {
1021 if (trace_probe_has_sibling(tp))
1022 return -EBUSY;
1023
1024 list_del_init(&tp->list);
1025 trace_probe_event_free(tp->event);
1026
1027 tp->event = to->event;
1028 list_add_tail(&tp->list, trace_probe_probe_list(to));
1029
1030 return 0;
1031 }
1032
trace_probe_unlink(struct trace_probe * tp)1033 void trace_probe_unlink(struct trace_probe *tp)
1034 {
1035 list_del_init(&tp->list);
1036 if (list_empty(trace_probe_probe_list(tp)))
1037 trace_probe_event_free(tp->event);
1038 tp->event = NULL;
1039 }
1040
trace_probe_cleanup(struct trace_probe * tp)1041 void trace_probe_cleanup(struct trace_probe *tp)
1042 {
1043 int i;
1044
1045 for (i = 0; i < tp->nr_args; i++)
1046 traceprobe_free_probe_arg(&tp->args[i]);
1047
1048 if (tp->event)
1049 trace_probe_unlink(tp);
1050 }
1051
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter)1052 int trace_probe_init(struct trace_probe *tp, const char *event,
1053 const char *group, bool alloc_filter)
1054 {
1055 struct trace_event_call *call;
1056 size_t size = sizeof(struct trace_probe_event);
1057 int ret = 0;
1058
1059 if (!event || !group)
1060 return -EINVAL;
1061
1062 if (alloc_filter)
1063 size += sizeof(struct trace_uprobe_filter);
1064
1065 tp->event = kzalloc(size, GFP_KERNEL);
1066 if (!tp->event)
1067 return -ENOMEM;
1068
1069 INIT_LIST_HEAD(&tp->event->files);
1070 INIT_LIST_HEAD(&tp->event->class.fields);
1071 INIT_LIST_HEAD(&tp->event->probes);
1072 INIT_LIST_HEAD(&tp->list);
1073 list_add(&tp->list, &tp->event->probes);
1074
1075 call = trace_probe_event_call(tp);
1076 call->class = &tp->event->class;
1077 call->name = kstrdup(event, GFP_KERNEL);
1078 if (!call->name) {
1079 ret = -ENOMEM;
1080 goto error;
1081 }
1082
1083 tp->event->class.system = kstrdup(group, GFP_KERNEL);
1084 if (!tp->event->class.system) {
1085 ret = -ENOMEM;
1086 goto error;
1087 }
1088
1089 return 0;
1090
1091 error:
1092 trace_probe_cleanup(tp);
1093 return ret;
1094 }
1095
1096 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)1097 find_trace_event_call(const char *system, const char *event_name)
1098 {
1099 struct trace_event_call *tp_event;
1100 const char *name;
1101
1102 list_for_each_entry(tp_event, &ftrace_events, list) {
1103 if (!tp_event->class->system ||
1104 strcmp(system, tp_event->class->system))
1105 continue;
1106 name = trace_event_name(tp_event);
1107 if (!name || strcmp(event_name, name))
1108 continue;
1109 return tp_event;
1110 }
1111
1112 return NULL;
1113 }
1114
trace_probe_register_event_call(struct trace_probe * tp)1115 int trace_probe_register_event_call(struct trace_probe *tp)
1116 {
1117 struct trace_event_call *call = trace_probe_event_call(tp);
1118 int ret;
1119
1120 lockdep_assert_held(&event_mutex);
1121
1122 if (find_trace_event_call(trace_probe_group_name(tp),
1123 trace_probe_name(tp)))
1124 return -EEXIST;
1125
1126 ret = register_trace_event(&call->event);
1127 if (!ret)
1128 return -ENODEV;
1129
1130 ret = trace_add_event_call(call);
1131 if (ret)
1132 unregister_trace_event(&call->event);
1133
1134 return ret;
1135 }
1136
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)1137 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1138 {
1139 struct event_file_link *link;
1140
1141 link = kmalloc(sizeof(*link), GFP_KERNEL);
1142 if (!link)
1143 return -ENOMEM;
1144
1145 link->file = file;
1146 INIT_LIST_HEAD(&link->list);
1147 list_add_tail_rcu(&link->list, &tp->event->files);
1148 trace_probe_set_flag(tp, TP_FLAG_TRACE);
1149 return 0;
1150 }
1151
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)1152 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1153 struct trace_event_file *file)
1154 {
1155 struct event_file_link *link;
1156
1157 trace_probe_for_each_link(link, tp) {
1158 if (link->file == file)
1159 return link;
1160 }
1161
1162 return NULL;
1163 }
1164
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)1165 int trace_probe_remove_file(struct trace_probe *tp,
1166 struct trace_event_file *file)
1167 {
1168 struct event_file_link *link;
1169
1170 link = trace_probe_get_file_link(tp, file);
1171 if (!link)
1172 return -ENOENT;
1173
1174 list_del_rcu(&link->list);
1175 kvfree_rcu(link);
1176
1177 if (list_empty(&tp->event->files))
1178 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1179
1180 return 0;
1181 }
1182
1183 /*
1184 * Return the smallest index of different type argument (start from 1).
1185 * If all argument types and name are same, return 0.
1186 */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)1187 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1188 {
1189 int i;
1190
1191 /* In case of more arguments */
1192 if (a->nr_args < b->nr_args)
1193 return a->nr_args + 1;
1194 if (a->nr_args > b->nr_args)
1195 return b->nr_args + 1;
1196
1197 for (i = 0; i < a->nr_args; i++) {
1198 if ((b->nr_args <= i) ||
1199 ((a->args[i].type != b->args[i].type) ||
1200 (a->args[i].count != b->args[i].count) ||
1201 strcmp(a->args[i].name, b->args[i].name)))
1202 return i + 1;
1203 }
1204
1205 return 0;
1206 }
1207
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)1208 bool trace_probe_match_command_args(struct trace_probe *tp,
1209 int argc, const char **argv)
1210 {
1211 char buf[MAX_ARGSTR_LEN + 1];
1212 int i;
1213
1214 if (tp->nr_args < argc)
1215 return false;
1216
1217 for (i = 0; i < argc; i++) {
1218 snprintf(buf, sizeof(buf), "%s=%s",
1219 tp->args[i].name, tp->args[i].comm);
1220 if (strcmp(buf, argv[i]))
1221 return false;
1222 }
1223 return true;
1224 }
1225
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))1226 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1227 {
1228 int argc = 0, ret = 0;
1229 char **argv;
1230
1231 argv = argv_split(GFP_KERNEL, raw_command, &argc);
1232 if (!argv)
1233 return -ENOMEM;
1234
1235 if (argc)
1236 ret = createfn(argc, (const char **)argv);
1237
1238 argv_free(argv);
1239
1240 return ret;
1241 }
1242
trace_probe_print_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)1243 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
1244 u8 *data, void *field)
1245 {
1246 void *p;
1247 int i, j;
1248
1249 for (i = 0; i < nr_args; i++) {
1250 struct probe_arg *a = args + i;
1251
1252 trace_seq_printf(s, " %s=", a->name);
1253 if (likely(!a->count)) {
1254 if (!a->type->print(s, data + a->offset, field))
1255 return -ENOMEM;
1256 continue;
1257 }
1258 trace_seq_putc(s, '{');
1259 p = data + a->offset;
1260 for (j = 0; j < a->count; j++) {
1261 if (!a->type->print(s, p, field))
1262 return -ENOMEM;
1263 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
1264 p += a->type->size;
1265 }
1266 }
1267 return 0;
1268 }
1269