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 <linux/bpf.h>
15 #include "trace_btf.h"
16
17 #include "trace_probe.h"
18
19 #undef C
20 #define C(a, b) b
21
22 static const char *trace_probe_err_text[] = { ERRORS };
23
24 static const char *reserved_field_names[] = {
25 "common_type",
26 "common_flags",
27 "common_preempt_count",
28 "common_pid",
29 "common_tgid",
30 FIELD_STRING_IP,
31 FIELD_STRING_RETIP,
32 FIELD_STRING_FUNC,
33 };
34
35 /* Printing in basic type function template */
36 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
37 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
38 { \
39 trace_seq_printf(s, fmt, *(type *)data); \
40 return !trace_seq_has_overflowed(s); \
41 } \
42 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
43
44 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
45 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
48 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
49 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
53 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
54 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
55 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
56 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
57
PRINT_TYPE_FUNC_NAME(symbol)58 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
59 {
60 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
61 return !trace_seq_has_overflowed(s);
62 }
63 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
64
65 /* Print type function for string type */
PRINT_TYPE_FUNC_NAME(string)66 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
67 {
68 int len = *(u32 *)data >> 16;
69
70 if (!len)
71 trace_seq_puts(s, FAULT_STRING);
72 else
73 trace_seq_printf(s, "\"%s\"",
74 (const char *)get_loc_data(data, ent));
75 return !trace_seq_has_overflowed(s);
76 }
77
78 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
79
80 /* Fetch type information table */
81 static const struct fetch_type probe_fetch_types[] = {
82 /* Special types */
83 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
84 "__data_loc char[]"),
85 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
86 "__data_loc char[]"),
87 __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
88 "__data_loc char[]"),
89 /* Basic types */
90 ASSIGN_FETCH_TYPE(u8, u8, 0),
91 ASSIGN_FETCH_TYPE(u16, u16, 0),
92 ASSIGN_FETCH_TYPE(u32, u32, 0),
93 ASSIGN_FETCH_TYPE(u64, u64, 0),
94 ASSIGN_FETCH_TYPE(s8, u8, 1),
95 ASSIGN_FETCH_TYPE(s16, u16, 1),
96 ASSIGN_FETCH_TYPE(s32, u32, 1),
97 ASSIGN_FETCH_TYPE(s64, u64, 1),
98 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
99 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
100 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
101 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
102 ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0),
103 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
104
105 ASSIGN_FETCH_TYPE_END
106 };
107
find_fetch_type(const char * type,unsigned long flags)108 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
109 {
110 int i;
111
112 /* Reject the symbol/symstr for uprobes */
113 if (type && (flags & TPARG_FL_USER) &&
114 (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
115 return NULL;
116
117 if (!type)
118 type = DEFAULT_FETCH_TYPE_STR;
119
120 /* Special case: bitfield */
121 if (*type == 'b') {
122 unsigned long bs;
123
124 type = strchr(type, '/');
125 if (!type)
126 goto fail;
127
128 type++;
129 if (kstrtoul(type, 0, &bs))
130 goto fail;
131
132 switch (bs) {
133 case 8:
134 return find_fetch_type("u8", flags);
135 case 16:
136 return find_fetch_type("u16", flags);
137 case 32:
138 return find_fetch_type("u32", flags);
139 case 64:
140 return find_fetch_type("u64", flags);
141 default:
142 goto fail;
143 }
144 }
145
146 for (i = 0; probe_fetch_types[i].name; i++) {
147 if (strcmp(type, probe_fetch_types[i].name) == 0)
148 return &probe_fetch_types[i];
149 }
150
151 fail:
152 return NULL;
153 }
154
155 static struct trace_probe_log trace_probe_log;
156 extern struct mutex dyn_event_ops_mutex;
157
trace_probe_log_init(const char * subsystem,int argc,const char ** argv)158 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
159 {
160 lockdep_assert_held(&dyn_event_ops_mutex);
161
162 trace_probe_log.subsystem = subsystem;
163 trace_probe_log.argc = argc;
164 trace_probe_log.argv = argv;
165 trace_probe_log.index = 0;
166 }
167
trace_probe_log_clear(void)168 void trace_probe_log_clear(void)
169 {
170 lockdep_assert_held(&dyn_event_ops_mutex);
171
172 memset(&trace_probe_log, 0, sizeof(trace_probe_log));
173 }
174
trace_probe_log_set_index(int index)175 void trace_probe_log_set_index(int index)
176 {
177 lockdep_assert_held(&dyn_event_ops_mutex);
178
179 trace_probe_log.index = index;
180 }
181
__trace_probe_log_err(int offset,int err_type)182 void __trace_probe_log_err(int offset, int err_type)
183 {
184 char *command, *p;
185 int i, len = 0, pos = 0;
186
187 lockdep_assert_held(&dyn_event_ops_mutex);
188
189 if (!trace_probe_log.argv)
190 return;
191
192 /* Recalculate the length and allocate buffer */
193 for (i = 0; i < trace_probe_log.argc; i++) {
194 if (i == trace_probe_log.index)
195 pos = len;
196 len += strlen(trace_probe_log.argv[i]) + 1;
197 }
198 command = kzalloc(len, GFP_KERNEL);
199 if (!command)
200 return;
201
202 if (trace_probe_log.index >= trace_probe_log.argc) {
203 /**
204 * Set the error position is next to the last arg + space.
205 * Note that len includes the terminal null and the cursor
206 * appears at pos + 1.
207 */
208 pos = len;
209 offset = 0;
210 }
211
212 /* And make a command string from argv array */
213 p = command;
214 for (i = 0; i < trace_probe_log.argc; i++) {
215 len = strlen(trace_probe_log.argv[i]);
216 strcpy(p, trace_probe_log.argv[i]);
217 p[len] = ' ';
218 p += len + 1;
219 }
220 *(p - 1) = '\0';
221
222 tracing_log_err(NULL, trace_probe_log.subsystem, command,
223 trace_probe_err_text, err_type, pos + offset);
224
225 kfree(command);
226 }
227
228 /* Split symbol and offset. */
traceprobe_split_symbol_offset(char * symbol,long * offset)229 int traceprobe_split_symbol_offset(char *symbol, long *offset)
230 {
231 char *tmp;
232 int ret;
233
234 if (!offset)
235 return -EINVAL;
236
237 tmp = strpbrk(symbol, "+-");
238 if (tmp) {
239 ret = kstrtol(tmp, 0, offset);
240 if (ret)
241 return ret;
242 *tmp = '\0';
243 } else
244 *offset = 0;
245
246 return 0;
247 }
248
249 /* @buf must has MAX_EVENT_NAME_LEN size */
traceprobe_parse_event_name(const char ** pevent,const char ** pgroup,char * buf,int offset)250 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
251 char *buf, int offset)
252 {
253 const char *slash, *event = *pevent;
254 int len;
255
256 slash = strchr(event, '/');
257 if (!slash)
258 slash = strchr(event, '.');
259
260 if (slash) {
261 if (slash == event) {
262 trace_probe_log_err(offset, NO_GROUP_NAME);
263 return -EINVAL;
264 }
265 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
266 trace_probe_log_err(offset, GROUP_TOO_LONG);
267 return -EINVAL;
268 }
269 strscpy(buf, event, slash - event + 1);
270 if (!is_good_system_name(buf)) {
271 trace_probe_log_err(offset, BAD_GROUP_NAME);
272 return -EINVAL;
273 }
274 *pgroup = buf;
275 *pevent = slash + 1;
276 offset += slash - event + 1;
277 event = *pevent;
278 }
279 len = strlen(event);
280 if (len == 0) {
281 if (slash) {
282 *pevent = NULL;
283 return 0;
284 }
285 trace_probe_log_err(offset, NO_EVENT_NAME);
286 return -EINVAL;
287 } else if (len >= MAX_EVENT_NAME_LEN) {
288 trace_probe_log_err(offset, EVENT_TOO_LONG);
289 return -EINVAL;
290 }
291 if (!is_good_name(event)) {
292 trace_probe_log_err(offset, BAD_EVENT_NAME);
293 return -EINVAL;
294 }
295 return 0;
296 }
297
parse_trace_event_arg(char * arg,struct fetch_insn * code,struct traceprobe_parse_context * ctx)298 static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
299 struct traceprobe_parse_context *ctx)
300 {
301 struct ftrace_event_field *field;
302 struct list_head *head;
303
304 head = trace_get_fields(ctx->event);
305 list_for_each_entry(field, head, link) {
306 if (!strcmp(arg, field->name)) {
307 code->op = FETCH_OP_TP_ARG;
308 code->data = field;
309 return 0;
310 }
311 }
312 return -ENOENT;
313 }
314
315 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
316
btf_type_int(const struct btf_type * t)317 static u32 btf_type_int(const struct btf_type *t)
318 {
319 return *(u32 *)(t + 1);
320 }
321
btf_type_is_char_ptr(struct btf * btf,const struct btf_type * type)322 static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
323 {
324 const struct btf_type *real_type;
325 u32 intdata;
326 s32 tid;
327
328 real_type = btf_type_skip_modifiers(btf, type->type, &tid);
329 if (!real_type)
330 return false;
331
332 if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
333 return false;
334
335 intdata = btf_type_int(real_type);
336 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
337 && BTF_INT_BITS(intdata) == 8;
338 }
339
btf_type_is_char_array(struct btf * btf,const struct btf_type * type)340 static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
341 {
342 const struct btf_type *real_type;
343 const struct btf_array *array;
344 u32 intdata;
345 s32 tid;
346
347 if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
348 return false;
349
350 array = (const struct btf_array *)(type + 1);
351
352 real_type = btf_type_skip_modifiers(btf, array->type, &tid);
353
354 intdata = btf_type_int(real_type);
355 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
356 && BTF_INT_BITS(intdata) == 8;
357 }
358
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)359 static int check_prepare_btf_string_fetch(char *typename,
360 struct fetch_insn **pcode,
361 struct traceprobe_parse_context *ctx)
362 {
363 struct btf *btf = ctx->btf;
364
365 if (!btf || !ctx->last_type)
366 return 0;
367
368 /* char [] does not need any change. */
369 if (btf_type_is_char_array(btf, ctx->last_type))
370 return 0;
371
372 /* char * requires dereference the pointer. */
373 if (btf_type_is_char_ptr(btf, ctx->last_type)) {
374 struct fetch_insn *code = *pcode + 1;
375
376 if (code->op == FETCH_OP_END) {
377 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
378 return -E2BIG;
379 }
380 if (typename[0] == 'u')
381 code->op = FETCH_OP_UDEREF;
382 else
383 code->op = FETCH_OP_DEREF;
384 code->offset = 0;
385 *pcode = code;
386 return 0;
387 }
388 /* Other types are not available for string */
389 trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
390 return -EINVAL;
391 }
392
fetch_type_from_btf_type(struct btf * btf,const struct btf_type * type,struct traceprobe_parse_context * ctx)393 static const char *fetch_type_from_btf_type(struct btf *btf,
394 const struct btf_type *type,
395 struct traceprobe_parse_context *ctx)
396 {
397 u32 intdata;
398
399 /* TODO: const char * could be converted as a string */
400 switch (BTF_INFO_KIND(type->info)) {
401 case BTF_KIND_ENUM:
402 /* enum is "int", so convert to "s32" */
403 return "s32";
404 case BTF_KIND_ENUM64:
405 return "s64";
406 case BTF_KIND_PTR:
407 /* pointer will be converted to "x??" */
408 if (IS_ENABLED(CONFIG_64BIT))
409 return "x64";
410 else
411 return "x32";
412 case BTF_KIND_INT:
413 intdata = btf_type_int(type);
414 if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
415 switch (BTF_INT_BITS(intdata)) {
416 case 8:
417 return "s8";
418 case 16:
419 return "s16";
420 case 32:
421 return "s32";
422 case 64:
423 return "s64";
424 }
425 } else { /* unsigned */
426 switch (BTF_INT_BITS(intdata)) {
427 case 8:
428 return "u8";
429 case 16:
430 return "u16";
431 case 32:
432 return "u32";
433 case 64:
434 return "u64";
435 }
436 /* bitfield, size is encoded in the type */
437 ctx->last_bitsize = BTF_INT_BITS(intdata);
438 ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
439 return "u64";
440 }
441 }
442 /* TODO: support other types */
443
444 return NULL;
445 }
446
query_btf_context(struct traceprobe_parse_context * ctx)447 static int query_btf_context(struct traceprobe_parse_context *ctx)
448 {
449 const struct btf_param *param;
450 const struct btf_type *type;
451 struct btf *btf;
452 s32 nr;
453
454 if (ctx->btf)
455 return 0;
456
457 if (!ctx->funcname)
458 return -EINVAL;
459
460 type = btf_find_func_proto(ctx->funcname, &btf);
461 if (!type)
462 return -ENOENT;
463
464 ctx->btf = btf;
465 ctx->proto = type;
466
467 /* ctx->params is optional, since func(void) will not have params. */
468 nr = 0;
469 param = btf_get_func_param(type, &nr);
470 if (!IS_ERR_OR_NULL(param)) {
471 /* Hide the first 'data' argument of tracepoint */
472 if (ctx->flags & TPARG_FL_TPOINT) {
473 nr--;
474 param++;
475 }
476 }
477
478 if (nr > 0) {
479 ctx->nr_params = nr;
480 ctx->params = param;
481 } else {
482 ctx->nr_params = 0;
483 ctx->params = NULL;
484 }
485
486 return 0;
487 }
488
clear_btf_context(struct traceprobe_parse_context * ctx)489 static void clear_btf_context(struct traceprobe_parse_context *ctx)
490 {
491 if (ctx->btf) {
492 btf_put(ctx->btf);
493 ctx->btf = NULL;
494 ctx->proto = NULL;
495 ctx->params = NULL;
496 ctx->nr_params = 0;
497 }
498 }
499
500 /* Return 1 if the field separater is arrow operator ('->') */
split_next_field(char * varname,char ** next_field,struct traceprobe_parse_context * ctx)501 static int split_next_field(char *varname, char **next_field,
502 struct traceprobe_parse_context *ctx)
503 {
504 char *field;
505 int ret = 0;
506
507 field = strpbrk(varname, ".-");
508 if (field) {
509 if (field[0] == '-' && field[1] == '>') {
510 field[0] = '\0';
511 field += 2;
512 ret = 1;
513 } else if (field[0] == '.') {
514 field[0] = '\0';
515 field += 1;
516 } else {
517 trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
518 return -EINVAL;
519 }
520 *next_field = field;
521 }
522
523 return ret;
524 }
525
526 /*
527 * Parse the field of data structure. The @type must be a pointer type
528 * pointing the target data structure type.
529 */
parse_btf_field(char * fieldname,const struct btf_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)530 static int parse_btf_field(char *fieldname, const struct btf_type *type,
531 struct fetch_insn **pcode, struct fetch_insn *end,
532 struct traceprobe_parse_context *ctx)
533 {
534 struct fetch_insn *code = *pcode;
535 const struct btf_member *field;
536 u32 bitoffs, anon_offs;
537 char *next;
538 int is_ptr;
539 s32 tid;
540
541 do {
542 /* Outer loop for solving arrow operator ('->') */
543 if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
544 trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
545 return -EINVAL;
546 }
547 /* Convert a struct pointer type to a struct type */
548 type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
549 if (!type) {
550 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
551 return -EINVAL;
552 }
553
554 bitoffs = 0;
555 do {
556 /* Inner loop for solving dot operator ('.') */
557 next = NULL;
558 is_ptr = split_next_field(fieldname, &next, ctx);
559 if (is_ptr < 0)
560 return is_ptr;
561
562 anon_offs = 0;
563 field = btf_find_struct_member(ctx->btf, type, fieldname,
564 &anon_offs);
565 if (IS_ERR(field)) {
566 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
567 return PTR_ERR(field);
568 }
569 if (!field) {
570 trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
571 return -ENOENT;
572 }
573 /* Add anonymous structure/union offset */
574 bitoffs += anon_offs;
575
576 /* Accumulate the bit-offsets of the dot-connected fields */
577 if (btf_type_kflag(type)) {
578 bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
579 ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
580 } else {
581 bitoffs += field->offset;
582 ctx->last_bitsize = 0;
583 }
584
585 type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
586 if (!type) {
587 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
588 return -EINVAL;
589 }
590
591 ctx->offset += next - fieldname;
592 fieldname = next;
593 } while (!is_ptr && fieldname);
594
595 if (++code == end) {
596 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
597 return -EINVAL;
598 }
599 code->op = FETCH_OP_DEREF; /* TODO: user deref support */
600 code->offset = bitoffs / 8;
601 *pcode = code;
602
603 ctx->last_bitoffs = bitoffs % 8;
604 ctx->last_type = type;
605 } while (fieldname);
606
607 return 0;
608 }
609
610 static int __store_entry_arg(struct trace_probe *tp, int argnum);
611
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)612 static int parse_btf_arg(char *varname,
613 struct fetch_insn **pcode, struct fetch_insn *end,
614 struct traceprobe_parse_context *ctx)
615 {
616 struct fetch_insn *code = *pcode;
617 const struct btf_param *params;
618 const struct btf_type *type;
619 char *field = NULL;
620 int i, is_ptr, ret;
621 u32 tid;
622
623 if (WARN_ON_ONCE(!ctx->funcname))
624 return -EINVAL;
625
626 is_ptr = split_next_field(varname, &field, ctx);
627 if (is_ptr < 0)
628 return is_ptr;
629 if (!is_ptr && field) {
630 /* dot-connected field on an argument is not supported. */
631 trace_probe_log_err(ctx->offset + field - varname,
632 NOSUP_DAT_ARG);
633 return -EOPNOTSUPP;
634 }
635
636 if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
637 code->op = FETCH_OP_RETVAL;
638 /* Check whether the function return type is not void */
639 if (query_btf_context(ctx) == 0) {
640 if (ctx->proto->type == 0) {
641 trace_probe_log_err(ctx->offset, NO_RETVAL);
642 return -ENOENT;
643 }
644 tid = ctx->proto->type;
645 goto found;
646 }
647 if (field) {
648 trace_probe_log_err(ctx->offset + field - varname,
649 NO_BTF_ENTRY);
650 return -ENOENT;
651 }
652 return 0;
653 }
654
655 if (!ctx->btf) {
656 ret = query_btf_context(ctx);
657 if (ret < 0 || ctx->nr_params == 0) {
658 trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
659 return PTR_ERR(params);
660 }
661 }
662 params = ctx->params;
663
664 for (i = 0; i < ctx->nr_params; i++) {
665 const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
666
667 if (name && !strcmp(name, varname)) {
668 if (tparg_is_function_entry(ctx->flags)) {
669 code->op = FETCH_OP_ARG;
670 if (ctx->flags & TPARG_FL_TPOINT)
671 code->param = i + 1;
672 else
673 code->param = i;
674 } else if (tparg_is_function_return(ctx->flags)) {
675 code->op = FETCH_OP_EDATA;
676 ret = __store_entry_arg(ctx->tp, i);
677 if (ret < 0) {
678 /* internal error */
679 return ret;
680 }
681 code->offset = ret;
682 }
683 tid = params[i].type;
684 goto found;
685 }
686 }
687 trace_probe_log_err(ctx->offset, NO_BTFARG);
688 return -ENOENT;
689
690 found:
691 type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
692 if (!type) {
693 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
694 return -EINVAL;
695 }
696 /* Initialize the last type information */
697 ctx->last_type = type;
698 ctx->last_bitoffs = 0;
699 ctx->last_bitsize = 0;
700 if (field) {
701 ctx->offset += field - varname;
702 return parse_btf_field(field, type, pcode, end, ctx);
703 }
704 return 0;
705 }
706
find_fetch_type_from_btf_type(struct traceprobe_parse_context * ctx)707 static const struct fetch_type *find_fetch_type_from_btf_type(
708 struct traceprobe_parse_context *ctx)
709 {
710 struct btf *btf = ctx->btf;
711 const char *typestr = NULL;
712
713 if (btf && ctx->last_type)
714 typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
715
716 return find_fetch_type(typestr, ctx->flags);
717 }
718
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)719 static int parse_btf_bitfield(struct fetch_insn **pcode,
720 struct traceprobe_parse_context *ctx)
721 {
722 struct fetch_insn *code = *pcode;
723
724 if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
725 return 0;
726
727 code++;
728 if (code->op != FETCH_OP_NOP) {
729 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
730 return -EINVAL;
731 }
732 *pcode = code;
733
734 code->op = FETCH_OP_MOD_BF;
735 code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
736 code->rshift = 64 - ctx->last_bitsize;
737 code->basesize = 64 / 8;
738 return 0;
739 }
740
741 #else
clear_btf_context(struct traceprobe_parse_context * ctx)742 static void clear_btf_context(struct traceprobe_parse_context *ctx)
743 {
744 ctx->btf = NULL;
745 }
746
query_btf_context(struct traceprobe_parse_context * ctx)747 static int query_btf_context(struct traceprobe_parse_context *ctx)
748 {
749 return -EOPNOTSUPP;
750 }
751
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)752 static int parse_btf_arg(char *varname,
753 struct fetch_insn **pcode, struct fetch_insn *end,
754 struct traceprobe_parse_context *ctx)
755 {
756 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
757 return -EOPNOTSUPP;
758 }
759
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)760 static int parse_btf_bitfield(struct fetch_insn **pcode,
761 struct traceprobe_parse_context *ctx)
762 {
763 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
764 return -EOPNOTSUPP;
765 }
766
767 #define find_fetch_type_from_btf_type(ctx) \
768 find_fetch_type(NULL, ctx->flags)
769
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)770 static int check_prepare_btf_string_fetch(char *typename,
771 struct fetch_insn **pcode,
772 struct traceprobe_parse_context *ctx)
773 {
774 return 0;
775 }
776
777 #endif
778
779 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
780
781 /*
782 * Add the entry code to store the 'argnum'th parameter and return the offset
783 * in the entry data buffer where the data will be stored.
784 */
__store_entry_arg(struct trace_probe * tp,int argnum)785 static int __store_entry_arg(struct trace_probe *tp, int argnum)
786 {
787 struct probe_entry_arg *earg = tp->entry_arg;
788 bool match = false;
789 int i, offset;
790
791 if (!earg) {
792 earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL);
793 if (!earg)
794 return -ENOMEM;
795 earg->size = 2 * tp->nr_args + 1;
796 earg->code = kcalloc(earg->size, sizeof(struct fetch_insn),
797 GFP_KERNEL);
798 if (!earg->code) {
799 kfree(earg);
800 return -ENOMEM;
801 }
802 /* Fill the code buffer with 'end' to simplify it */
803 for (i = 0; i < earg->size; i++)
804 earg->code[i].op = FETCH_OP_END;
805 tp->entry_arg = earg;
806 }
807
808 /*
809 * The entry code array is repeating the pair of
810 * [FETCH_OP_ARG(argnum)][FETCH_OP_ST_EDATA(offset of entry data buffer)]
811 * and the rest of entries are filled with [FETCH_OP_END].
812 *
813 * To reduce the redundant function parameter fetching, we scan the entry
814 * code array to find the FETCH_OP_ARG which already fetches the 'argnum'
815 * parameter. If it doesn't match, update 'offset' to find the last
816 * offset.
817 * If we find the FETCH_OP_END without matching FETCH_OP_ARG entry, we
818 * will save the entry with FETCH_OP_ARG and FETCH_OP_ST_EDATA, and
819 * return data offset so that caller can find the data offset in the entry
820 * data buffer.
821 */
822 offset = 0;
823 for (i = 0; i < earg->size - 1; i++) {
824 switch (earg->code[i].op) {
825 case FETCH_OP_END:
826 earg->code[i].op = FETCH_OP_ARG;
827 earg->code[i].param = argnum;
828 earg->code[i + 1].op = FETCH_OP_ST_EDATA;
829 earg->code[i + 1].offset = offset;
830 return offset;
831 case FETCH_OP_ARG:
832 match = (earg->code[i].param == argnum);
833 break;
834 case FETCH_OP_ST_EDATA:
835 offset = earg->code[i].offset;
836 if (match)
837 return offset;
838 offset += sizeof(unsigned long);
839 break;
840 default:
841 break;
842 }
843 }
844 return -ENOSPC;
845 }
846
traceprobe_get_entry_data_size(struct trace_probe * tp)847 int traceprobe_get_entry_data_size(struct trace_probe *tp)
848 {
849 struct probe_entry_arg *earg = tp->entry_arg;
850 int i, size = 0;
851
852 if (!earg)
853 return 0;
854
855 /*
856 * earg->code[] array has an operation sequence which is run in
857 * the entry handler.
858 * The sequence stopped by FETCH_OP_END and each data stored in
859 * the entry data buffer by FETCH_OP_ST_EDATA. The FETCH_OP_ST_EDATA
860 * stores the data at the data buffer + its offset, and all data are
861 * "unsigned long" size. The offset must be increased when a data is
862 * stored. Thus we need to find the last FETCH_OP_ST_EDATA in the
863 * code array.
864 */
865 for (i = 0; i < earg->size; i++) {
866 switch (earg->code[i].op) {
867 case FETCH_OP_END:
868 goto out;
869 case FETCH_OP_ST_EDATA:
870 size = earg->code[i].offset + sizeof(unsigned long);
871 break;
872 default:
873 break;
874 }
875 }
876 out:
877 return size;
878 }
879
store_trace_entry_data(void * edata,struct trace_probe * tp,struct pt_regs * regs)880 void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
881 {
882 struct probe_entry_arg *earg = tp->entry_arg;
883 unsigned long val = 0;
884 int i;
885
886 if (!earg)
887 return;
888
889 for (i = 0; i < earg->size; i++) {
890 struct fetch_insn *code = &earg->code[i];
891
892 switch (code->op) {
893 case FETCH_OP_ARG:
894 val = regs_get_kernel_argument(regs, code->param);
895 break;
896 case FETCH_OP_ST_EDATA:
897 *(unsigned long *)((unsigned long)edata + code->offset) = val;
898 break;
899 case FETCH_OP_END:
900 goto end;
901 default:
902 break;
903 }
904 }
905 end:
906 return;
907 }
NOKPROBE_SYMBOL(store_trace_entry_data)908 NOKPROBE_SYMBOL(store_trace_entry_data)
909 #endif
910
911 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
912
913 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
914 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
915 struct fetch_insn **pcode,
916 struct fetch_insn *end,
917 struct traceprobe_parse_context *ctx)
918 {
919 struct fetch_insn *code = *pcode;
920 int err = TP_ERR_BAD_VAR;
921 char *arg = orig_arg + 1;
922 unsigned long param;
923 int ret = 0;
924 int len;
925
926 if (ctx->flags & TPARG_FL_TEVENT) {
927 if (code->data)
928 return -EFAULT;
929 ret = parse_trace_event_arg(arg, code, ctx);
930 if (!ret)
931 return 0;
932 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
933 code->op = FETCH_OP_COMM;
934 return 0;
935 }
936 /* backward compatibility */
937 ctx->offset = 0;
938 goto inval;
939 }
940
941 if (str_has_prefix(arg, "retval")) {
942 if (!(ctx->flags & TPARG_FL_RETURN)) {
943 err = TP_ERR_RETVAL_ON_PROBE;
944 goto inval;
945 }
946 if (!(ctx->flags & TPARG_FL_KERNEL) ||
947 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
948 code->op = FETCH_OP_RETVAL;
949 return 0;
950 }
951 return parse_btf_arg(orig_arg, pcode, end, ctx);
952 }
953
954 len = str_has_prefix(arg, "stack");
955 if (len) {
956
957 if (arg[len] == '\0') {
958 code->op = FETCH_OP_STACKP;
959 return 0;
960 }
961
962 if (isdigit(arg[len])) {
963 ret = kstrtoul(arg + len, 10, ¶m);
964 if (ret)
965 goto inval;
966
967 if ((ctx->flags & TPARG_FL_KERNEL) &&
968 param > PARAM_MAX_STACK) {
969 err = TP_ERR_BAD_STACK_NUM;
970 goto inval;
971 }
972 code->op = FETCH_OP_STACK;
973 code->param = (unsigned int)param;
974 return 0;
975 }
976 goto inval;
977 }
978
979 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
980 code->op = FETCH_OP_COMM;
981 return 0;
982 }
983
984 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
985 len = str_has_prefix(arg, "arg");
986 if (len) {
987 ret = kstrtoul(arg + len, 10, ¶m);
988 if (ret)
989 goto inval;
990
991 if (!param || param > PARAM_MAX_STACK) {
992 err = TP_ERR_BAD_ARG_NUM;
993 goto inval;
994 }
995 param--; /* argN starts from 1, but internal arg[N] starts from 0 */
996
997 if (tparg_is_function_entry(ctx->flags)) {
998 code->op = FETCH_OP_ARG;
999 code->param = (unsigned int)param;
1000 /*
1001 * The tracepoint probe will probe a stub function, and the
1002 * first parameter of the stub is a dummy and should be ignored.
1003 */
1004 if (ctx->flags & TPARG_FL_TPOINT)
1005 code->param++;
1006 } else if (tparg_is_function_return(ctx->flags)) {
1007 /* function entry argument access from return probe */
1008 ret = __store_entry_arg(ctx->tp, param);
1009 if (ret < 0) /* This error should be an internal error */
1010 return ret;
1011
1012 code->op = FETCH_OP_EDATA;
1013 code->offset = ret;
1014 } else {
1015 err = TP_ERR_NOFENTRY_ARGS;
1016 goto inval;
1017 }
1018 return 0;
1019 }
1020 #endif
1021
1022 inval:
1023 __trace_probe_log_err(ctx->offset, err);
1024 return -EINVAL;
1025 }
1026
str_to_immediate(char * str,unsigned long * imm)1027 static int str_to_immediate(char *str, unsigned long *imm)
1028 {
1029 if (isdigit(str[0]))
1030 return kstrtoul(str, 0, imm);
1031 else if (str[0] == '-')
1032 return kstrtol(str, 0, (long *)imm);
1033 else if (str[0] == '+')
1034 return kstrtol(str + 1, 0, (long *)imm);
1035 return -EINVAL;
1036 }
1037
__parse_imm_string(char * str,char ** pbuf,int offs)1038 static int __parse_imm_string(char *str, char **pbuf, int offs)
1039 {
1040 size_t len = strlen(str);
1041
1042 if (str[len - 1] != '"') {
1043 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1044 return -EINVAL;
1045 }
1046 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1047 if (!*pbuf)
1048 return -ENOMEM;
1049 return 0;
1050 }
1051
1052 /* Recursive argument parser */
1053 static int
parse_probe_arg(char * arg,const struct fetch_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)1054 parse_probe_arg(char *arg, const struct fetch_type *type,
1055 struct fetch_insn **pcode, struct fetch_insn *end,
1056 struct traceprobe_parse_context *ctx)
1057 {
1058 struct fetch_insn *code = *pcode;
1059 unsigned long param;
1060 int deref = FETCH_OP_DEREF;
1061 long offset = 0;
1062 char *tmp;
1063 int ret = 0;
1064
1065 switch (arg[0]) {
1066 case '$':
1067 ret = parse_probe_vars(arg, type, pcode, end, ctx);
1068 break;
1069
1070 case '%': /* named register */
1071 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1072 /* eprobe and fprobe do not handle registers */
1073 trace_probe_log_err(ctx->offset, BAD_VAR);
1074 break;
1075 }
1076 ret = regs_query_register_offset(arg + 1);
1077 if (ret >= 0) {
1078 code->op = FETCH_OP_REG;
1079 code->param = (unsigned int)ret;
1080 ret = 0;
1081 } else
1082 trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1083 break;
1084
1085 case '@': /* memory, file-offset or symbol */
1086 if (isdigit(arg[1])) {
1087 ret = kstrtoul(arg + 1, 0, ¶m);
1088 if (ret) {
1089 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1090 break;
1091 }
1092 /* load address */
1093 code->op = FETCH_OP_IMM;
1094 code->immediate = param;
1095 } else if (arg[1] == '+') {
1096 /* kprobes don't support file offsets */
1097 if (ctx->flags & TPARG_FL_KERNEL) {
1098 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1099 return -EINVAL;
1100 }
1101 ret = kstrtol(arg + 2, 0, &offset);
1102 if (ret) {
1103 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1104 break;
1105 }
1106
1107 code->op = FETCH_OP_FOFFS;
1108 code->immediate = (unsigned long)offset; // imm64?
1109 } else {
1110 /* uprobes don't support symbols */
1111 if (!(ctx->flags & TPARG_FL_KERNEL)) {
1112 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1113 return -EINVAL;
1114 }
1115 /* Preserve symbol for updating */
1116 code->op = FETCH_NOP_SYMBOL;
1117 code->data = kstrdup(arg + 1, GFP_KERNEL);
1118 if (!code->data)
1119 return -ENOMEM;
1120 if (++code == end) {
1121 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1122 return -EINVAL;
1123 }
1124 code->op = FETCH_OP_IMM;
1125 code->immediate = 0;
1126 }
1127 /* These are fetching from memory */
1128 if (++code == end) {
1129 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1130 return -EINVAL;
1131 }
1132 *pcode = code;
1133 code->op = FETCH_OP_DEREF;
1134 code->offset = offset;
1135 break;
1136
1137 case '+': /* deref memory */
1138 case '-':
1139 if (arg[1] == 'u') {
1140 deref = FETCH_OP_UDEREF;
1141 arg[1] = arg[0];
1142 arg++;
1143 }
1144 if (arg[0] == '+')
1145 arg++; /* Skip '+', because kstrtol() rejects it. */
1146 tmp = strchr(arg, '(');
1147 if (!tmp) {
1148 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1149 return -EINVAL;
1150 }
1151 *tmp = '\0';
1152 ret = kstrtol(arg, 0, &offset);
1153 if (ret) {
1154 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1155 break;
1156 }
1157 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1158 arg = tmp + 1;
1159 tmp = strrchr(arg, ')');
1160 if (!tmp) {
1161 trace_probe_log_err(ctx->offset + strlen(arg),
1162 DEREF_OPEN_BRACE);
1163 return -EINVAL;
1164 } else {
1165 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1166 int cur_offs = ctx->offset;
1167
1168 *tmp = '\0';
1169 ret = parse_probe_arg(arg, t2, &code, end, ctx);
1170 if (ret)
1171 break;
1172 ctx->offset = cur_offs;
1173 if (code->op == FETCH_OP_COMM ||
1174 code->op == FETCH_OP_DATA) {
1175 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1176 return -EINVAL;
1177 }
1178 if (++code == end) {
1179 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1180 return -EINVAL;
1181 }
1182 *pcode = code;
1183
1184 code->op = deref;
1185 code->offset = offset;
1186 /* Reset the last type if used */
1187 ctx->last_type = NULL;
1188 }
1189 break;
1190 case '\\': /* Immediate value */
1191 if (arg[1] == '"') { /* Immediate string */
1192 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1193 if (ret)
1194 break;
1195 code->op = FETCH_OP_DATA;
1196 code->data = tmp;
1197 } else {
1198 ret = str_to_immediate(arg + 1, &code->immediate);
1199 if (ret)
1200 trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1201 else
1202 code->op = FETCH_OP_IMM;
1203 }
1204 break;
1205 default:
1206 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
1207 if (!tparg_is_function_entry(ctx->flags) &&
1208 !tparg_is_function_return(ctx->flags)) {
1209 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1210 return -EINVAL;
1211 }
1212 ret = parse_btf_arg(arg, pcode, end, ctx);
1213 break;
1214 }
1215 }
1216 if (!ret && code->op == FETCH_OP_NOP) {
1217 /* Parsed, but do not find fetch method */
1218 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1219 ret = -EINVAL;
1220 }
1221 return ret;
1222 }
1223
1224 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
1225
1226 /* 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)1227 static int __parse_bitfield_probe_arg(const char *bf,
1228 const struct fetch_type *t,
1229 struct fetch_insn **pcode)
1230 {
1231 struct fetch_insn *code = *pcode;
1232 unsigned long bw, bo;
1233 char *tail;
1234
1235 if (*bf != 'b')
1236 return 0;
1237
1238 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
1239
1240 if (bw == 0 || *tail != '@')
1241 return -EINVAL;
1242
1243 bf = tail + 1;
1244 bo = simple_strtoul(bf, &tail, 0);
1245
1246 if (tail == bf || *tail != '/')
1247 return -EINVAL;
1248 code++;
1249 if (code->op != FETCH_OP_NOP)
1250 return -EINVAL;
1251 *pcode = code;
1252
1253 code->op = FETCH_OP_MOD_BF;
1254 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1255 code->rshift = BYTES_TO_BITS(t->size) - bw;
1256 code->basesize = t->size;
1257
1258 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1259 }
1260
1261 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1262 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1263 struct probe_arg *parg,
1264 struct traceprobe_parse_context *ctx)
1265 {
1266 struct fetch_insn *code, *scode, *tmp = NULL;
1267 char *t, *t2, *t3;
1268 int ret, len;
1269 char *arg;
1270
1271 arg = kstrdup(argv, GFP_KERNEL);
1272 if (!arg)
1273 return -ENOMEM;
1274
1275 ret = -EINVAL;
1276 len = strlen(arg);
1277 if (len > MAX_ARGSTR_LEN) {
1278 trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1279 goto out;
1280 } else if (len == 0) {
1281 trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1282 goto out;
1283 }
1284
1285 ret = -ENOMEM;
1286 parg->comm = kstrdup(arg, GFP_KERNEL);
1287 if (!parg->comm)
1288 goto out;
1289
1290 ret = -EINVAL;
1291 t = strchr(arg, ':');
1292 if (t) {
1293 *t = '\0';
1294 t2 = strchr(++t, '[');
1295 if (t2) {
1296 *t2++ = '\0';
1297 t3 = strchr(t2, ']');
1298 if (!t3) {
1299 int offs = t2 + strlen(t2) - arg;
1300
1301 trace_probe_log_err(ctx->offset + offs,
1302 ARRAY_NO_CLOSE);
1303 goto out;
1304 } else if (t3[1] != '\0') {
1305 trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1306 BAD_ARRAY_SUFFIX);
1307 goto out;
1308 }
1309 *t3 = '\0';
1310 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1311 trace_probe_log_err(ctx->offset + t2 - arg,
1312 BAD_ARRAY_NUM);
1313 goto out;
1314 }
1315 if (parg->count > MAX_ARRAY_LEN) {
1316 trace_probe_log_err(ctx->offset + t2 - arg,
1317 ARRAY_TOO_BIG);
1318 goto out;
1319 }
1320 }
1321 }
1322
1323 /*
1324 * Since $comm and immediate string can not be dereferenced,
1325 * we can find those by strcmp. But ignore for eprobes.
1326 */
1327 if (!(ctx->flags & TPARG_FL_TEVENT) &&
1328 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1329 strncmp(arg, "\\\"", 2) == 0)) {
1330 /* The type of $comm must be "string", and not an array type. */
1331 if (parg->count || (t && strcmp(t, "string"))) {
1332 trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1333 NEED_STRING_TYPE);
1334 goto out;
1335 }
1336 parg->type = find_fetch_type("string", ctx->flags);
1337 } else
1338 parg->type = find_fetch_type(t, ctx->flags);
1339 if (!parg->type) {
1340 trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0), BAD_TYPE);
1341 goto out;
1342 }
1343
1344 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
1345 if (!code)
1346 goto out;
1347 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1348
1349 ctx->last_type = NULL;
1350 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1351 ctx);
1352 if (ret)
1353 goto fail;
1354
1355 /* Update storing type if BTF is available */
1356 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1357 ctx->last_type) {
1358 if (!t) {
1359 parg->type = find_fetch_type_from_btf_type(ctx);
1360 } else if (strstr(t, "string")) {
1361 ret = check_prepare_btf_string_fetch(t, &code, ctx);
1362 if (ret)
1363 goto fail;
1364 }
1365 }
1366 parg->offset = *size;
1367 *size += parg->type->size * (parg->count ?: 1);
1368
1369 if (parg->count) {
1370 len = strlen(parg->type->fmttype) + 6;
1371 parg->fmt = kmalloc(len, GFP_KERNEL);
1372 if (!parg->fmt) {
1373 ret = -ENOMEM;
1374 goto out;
1375 }
1376 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1377 parg->count);
1378 }
1379
1380 ret = -EINVAL;
1381 /* Store operation */
1382 if (parg->type->is_string) {
1383 if (!strcmp(parg->type->name, "symstr")) {
1384 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1385 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1386 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1387 trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1388 BAD_SYMSTRING);
1389 goto fail;
1390 }
1391 } else {
1392 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1393 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1394 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1395 trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1396 BAD_STRING);
1397 goto fail;
1398 }
1399 }
1400 if (!strcmp(parg->type->name, "symstr") ||
1401 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1402 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1403 parg->count) {
1404 /*
1405 * IMM, DATA and COMM is pointing actual address, those
1406 * must be kept, and if parg->count != 0, this is an
1407 * array of string pointers instead of string address
1408 * itself.
1409 * For the symstr, it doesn't need to dereference, thus
1410 * it just get the value.
1411 */
1412 code++;
1413 if (code->op != FETCH_OP_NOP) {
1414 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1415 goto fail;
1416 }
1417 }
1418 /* If op == DEREF, replace it with STRING */
1419 if (!strcmp(parg->type->name, "ustring") ||
1420 code->op == FETCH_OP_UDEREF)
1421 code->op = FETCH_OP_ST_USTRING;
1422 else if (!strcmp(parg->type->name, "symstr"))
1423 code->op = FETCH_OP_ST_SYMSTR;
1424 else
1425 code->op = FETCH_OP_ST_STRING;
1426 code->size = parg->type->size;
1427 parg->dynamic = true;
1428 } else if (code->op == FETCH_OP_DEREF) {
1429 code->op = FETCH_OP_ST_MEM;
1430 code->size = parg->type->size;
1431 } else if (code->op == FETCH_OP_UDEREF) {
1432 code->op = FETCH_OP_ST_UMEM;
1433 code->size = parg->type->size;
1434 } else {
1435 code++;
1436 if (code->op != FETCH_OP_NOP) {
1437 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1438 goto fail;
1439 }
1440 code->op = FETCH_OP_ST_RAW;
1441 code->size = parg->type->size;
1442 }
1443 scode = code;
1444 /* Modify operation */
1445 if (t != NULL) {
1446 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
1447 if (ret) {
1448 trace_probe_log_err(ctx->offset + t - arg, BAD_BITFIELD);
1449 goto fail;
1450 }
1451 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1452 ctx->last_type) {
1453 ret = parse_btf_bitfield(&code, ctx);
1454 if (ret)
1455 goto fail;
1456 }
1457 ret = -EINVAL;
1458 /* Loop(Array) operation */
1459 if (parg->count) {
1460 if (scode->op != FETCH_OP_ST_MEM &&
1461 scode->op != FETCH_OP_ST_STRING &&
1462 scode->op != FETCH_OP_ST_USTRING) {
1463 trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1464 BAD_STRING);
1465 goto fail;
1466 }
1467 code++;
1468 if (code->op != FETCH_OP_NOP) {
1469 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1470 goto fail;
1471 }
1472 code->op = FETCH_OP_LP_ARRAY;
1473 code->param = parg->count;
1474 }
1475 code++;
1476 code->op = FETCH_OP_END;
1477
1478 ret = 0;
1479 /* Shrink down the code buffer */
1480 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1481 if (!parg->code)
1482 ret = -ENOMEM;
1483 else
1484 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1485
1486 fail:
1487 if (ret) {
1488 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1489 if (code->op == FETCH_NOP_SYMBOL ||
1490 code->op == FETCH_OP_DATA)
1491 kfree(code->data);
1492 }
1493 kfree(tmp);
1494 out:
1495 kfree(arg);
1496
1497 return ret;
1498 }
1499
1500 /* 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)1501 static int traceprobe_conflict_field_name(const char *name,
1502 struct probe_arg *args, int narg)
1503 {
1504 int i;
1505
1506 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1507 if (strcmp(reserved_field_names[i], name) == 0)
1508 return 1;
1509
1510 for (i = 0; i < narg; i++)
1511 if (strcmp(args[i].name, name) == 0)
1512 return 1;
1513
1514 return 0;
1515 }
1516
generate_probe_arg_name(const char * arg,int idx)1517 static char *generate_probe_arg_name(const char *arg, int idx)
1518 {
1519 char *name = NULL;
1520 const char *end;
1521
1522 /*
1523 * If argument name is omitted, try arg as a name (BTF variable)
1524 * or "argN".
1525 */
1526 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1527 end = strchr(arg, ':');
1528 if (!end)
1529 end = arg + strlen(arg);
1530
1531 name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1532 if (!name || !is_good_name(name)) {
1533 kfree(name);
1534 name = NULL;
1535 }
1536 }
1537
1538 if (!name)
1539 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1540
1541 return name;
1542 }
1543
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,struct traceprobe_parse_context * ctx)1544 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1545 struct traceprobe_parse_context *ctx)
1546 {
1547 struct probe_arg *parg = &tp->args[i];
1548 const char *body;
1549
1550 ctx->tp = tp;
1551 body = strchr(arg, '=');
1552 if (body) {
1553 if (body - arg > MAX_ARG_NAME_LEN) {
1554 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1555 return -EINVAL;
1556 } else if (body == arg) {
1557 trace_probe_log_err(0, NO_ARG_NAME);
1558 return -EINVAL;
1559 }
1560 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1561 body++;
1562 } else {
1563 parg->name = generate_probe_arg_name(arg, i);
1564 body = arg;
1565 }
1566 if (!parg->name)
1567 return -ENOMEM;
1568
1569 if (!is_good_name(parg->name)) {
1570 trace_probe_log_err(0, BAD_ARG_NAME);
1571 return -EINVAL;
1572 }
1573 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1574 trace_probe_log_err(0, USED_ARG_NAME);
1575 return -EINVAL;
1576 }
1577 ctx->offset = body - arg;
1578 /* Parse fetch argument */
1579 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1580 }
1581
traceprobe_free_probe_arg(struct probe_arg * arg)1582 void traceprobe_free_probe_arg(struct probe_arg *arg)
1583 {
1584 struct fetch_insn *code = arg->code;
1585
1586 while (code && code->op != FETCH_OP_END) {
1587 if (code->op == FETCH_NOP_SYMBOL ||
1588 code->op == FETCH_OP_DATA)
1589 kfree(code->data);
1590 code++;
1591 }
1592 kfree(arg->code);
1593 kfree(arg->name);
1594 kfree(arg->comm);
1595 kfree(arg->fmt);
1596 }
1597
argv_has_var_arg(int argc,const char * argv[],int * args_idx,struct traceprobe_parse_context * ctx)1598 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1599 struct traceprobe_parse_context *ctx)
1600 {
1601 int i, found = 0;
1602
1603 for (i = 0; i < argc; i++)
1604 if (str_has_prefix(argv[i], "$arg")) {
1605 trace_probe_log_set_index(i + 2);
1606
1607 if (!tparg_is_function_entry(ctx->flags) &&
1608 !tparg_is_function_return(ctx->flags)) {
1609 trace_probe_log_err(0, NOFENTRY_ARGS);
1610 return -EINVAL;
1611 }
1612
1613 if (isdigit(argv[i][4])) {
1614 found = 1;
1615 continue;
1616 }
1617
1618 if (argv[i][4] != '*') {
1619 trace_probe_log_err(0, BAD_VAR);
1620 return -EINVAL;
1621 }
1622
1623 if (*args_idx >= 0 && *args_idx < argc) {
1624 trace_probe_log_err(0, DOUBLE_ARGS);
1625 return -EINVAL;
1626 }
1627 found = 1;
1628 *args_idx = i;
1629 }
1630
1631 return found;
1632 }
1633
sprint_nth_btf_arg(int idx,const char * type,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1634 static int sprint_nth_btf_arg(int idx, const char *type,
1635 char *buf, int bufsize,
1636 struct traceprobe_parse_context *ctx)
1637 {
1638 const char *name;
1639 int ret;
1640
1641 if (idx >= ctx->nr_params) {
1642 trace_probe_log_err(0, NO_BTFARG);
1643 return -ENOENT;
1644 }
1645 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1646 if (!name) {
1647 trace_probe_log_err(0, NO_BTF_ENTRY);
1648 return -ENOENT;
1649 }
1650 ret = snprintf(buf, bufsize, "%s%s", name, type);
1651 if (ret >= bufsize) {
1652 trace_probe_log_err(0, ARGS_2LONG);
1653 return -E2BIG;
1654 }
1655 return ret;
1656 }
1657
1658 /* Return new_argv which must be freed after use */
traceprobe_expand_meta_args(int argc,const char * argv[],int * new_argc,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1659 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1660 int *new_argc, char *buf, int bufsize,
1661 struct traceprobe_parse_context *ctx)
1662 {
1663 const struct btf_param *params = NULL;
1664 int i, j, n, used, ret, args_idx = -1;
1665 const char **new_argv = NULL;
1666
1667 ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1668 if (ret < 0)
1669 return ERR_PTR(ret);
1670
1671 if (!ret) {
1672 *new_argc = argc;
1673 return NULL;
1674 }
1675
1676 ret = query_btf_context(ctx);
1677 if (ret < 0 || ctx->nr_params == 0) {
1678 if (args_idx != -1) {
1679 /* $arg* requires BTF info */
1680 trace_probe_log_err(0, NOSUP_BTFARG);
1681 return (const char **)params;
1682 }
1683 *new_argc = argc;
1684 return NULL;
1685 }
1686
1687 if (args_idx >= 0)
1688 *new_argc = argc + ctx->nr_params - 1;
1689 else
1690 *new_argc = argc;
1691
1692 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1693 if (!new_argv)
1694 return ERR_PTR(-ENOMEM);
1695
1696 used = 0;
1697 for (i = 0, j = 0; i < argc; i++) {
1698 trace_probe_log_set_index(i + 2);
1699 if (i == args_idx) {
1700 for (n = 0; n < ctx->nr_params; n++) {
1701 ret = sprint_nth_btf_arg(n, "", buf + used,
1702 bufsize - used, ctx);
1703 if (ret < 0)
1704 goto error;
1705
1706 new_argv[j++] = buf + used;
1707 used += ret + 1;
1708 }
1709 continue;
1710 }
1711
1712 if (str_has_prefix(argv[i], "$arg")) {
1713 char *type = NULL;
1714
1715 n = simple_strtoul(argv[i] + 4, &type, 10);
1716 if (type && !(*type == ':' || *type == '\0')) {
1717 trace_probe_log_err(0, BAD_VAR);
1718 ret = -ENOENT;
1719 goto error;
1720 }
1721 /* Note: $argN starts from $arg1 */
1722 ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1723 bufsize - used, ctx);
1724 if (ret < 0)
1725 goto error;
1726 new_argv[j++] = buf + used;
1727 used += ret + 1;
1728 } else
1729 new_argv[j++] = argv[i];
1730 }
1731
1732 return new_argv;
1733
1734 error:
1735 kfree(new_argv);
1736 return ERR_PTR(ret);
1737 }
1738
traceprobe_finish_parse(struct traceprobe_parse_context * ctx)1739 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1740 {
1741 clear_btf_context(ctx);
1742 }
1743
traceprobe_update_arg(struct probe_arg * arg)1744 int traceprobe_update_arg(struct probe_arg *arg)
1745 {
1746 struct fetch_insn *code = arg->code;
1747 long offset;
1748 char *tmp;
1749 char c;
1750 int ret = 0;
1751
1752 while (code && code->op != FETCH_OP_END) {
1753 if (code->op == FETCH_NOP_SYMBOL) {
1754 if (code[1].op != FETCH_OP_IMM)
1755 return -EINVAL;
1756
1757 tmp = strpbrk(code->data, "+-");
1758 if (tmp)
1759 c = *tmp;
1760 ret = traceprobe_split_symbol_offset(code->data,
1761 &offset);
1762 if (ret)
1763 return ret;
1764
1765 code[1].immediate =
1766 (unsigned long)kallsyms_lookup_name(code->data);
1767 if (tmp)
1768 *tmp = c;
1769 if (!code[1].immediate)
1770 return -ENOENT;
1771 code[1].immediate += offset;
1772 }
1773 code++;
1774 }
1775 return 0;
1776 }
1777
1778 /* When len=0, we just calculate the needed length */
1779 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)1780 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1781 enum probe_print_type ptype)
1782 {
1783 struct probe_arg *parg;
1784 int i, j;
1785 int pos = 0;
1786 const char *fmt, *arg;
1787
1788 switch (ptype) {
1789 case PROBE_PRINT_NORMAL:
1790 fmt = "(%lx)";
1791 arg = ", REC->" FIELD_STRING_IP;
1792 break;
1793 case PROBE_PRINT_RETURN:
1794 fmt = "(%lx <- %lx)";
1795 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1796 break;
1797 case PROBE_PRINT_EVENT:
1798 fmt = "";
1799 arg = "";
1800 break;
1801 default:
1802 WARN_ON_ONCE(1);
1803 return 0;
1804 }
1805
1806 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1807
1808 for (i = 0; i < tp->nr_args; i++) {
1809 parg = tp->args + i;
1810 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1811 if (parg->count) {
1812 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1813 parg->type->fmt);
1814 for (j = 1; j < parg->count; j++)
1815 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1816 parg->type->fmt);
1817 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1818 } else
1819 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1820 parg->type->fmt);
1821 }
1822
1823 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1824
1825 for (i = 0; i < tp->nr_args; i++) {
1826 parg = tp->args + i;
1827 if (parg->count) {
1828 if (parg->type->is_string)
1829 fmt = ", __get_str(%s[%d])";
1830 else
1831 fmt = ", REC->%s[%d]";
1832 for (j = 0; j < parg->count; j++)
1833 pos += snprintf(buf + pos, LEN_OR_ZERO,
1834 fmt, parg->name, j);
1835 } else {
1836 if (parg->type->is_string)
1837 fmt = ", __get_str(%s)";
1838 else
1839 fmt = ", REC->%s";
1840 pos += snprintf(buf + pos, LEN_OR_ZERO,
1841 fmt, parg->name);
1842 }
1843 }
1844
1845 /* return the length of print_fmt */
1846 return pos;
1847 }
1848 #undef LEN_OR_ZERO
1849
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)1850 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1851 {
1852 struct trace_event_call *call = trace_probe_event_call(tp);
1853 int len;
1854 char *print_fmt;
1855
1856 /* First: called with 0 length to calculate the needed length */
1857 len = __set_print_fmt(tp, NULL, 0, ptype);
1858 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1859 if (!print_fmt)
1860 return -ENOMEM;
1861
1862 /* Second: actually write the @print_fmt */
1863 __set_print_fmt(tp, print_fmt, len + 1, ptype);
1864 call->print_fmt = print_fmt;
1865
1866 return 0;
1867 }
1868
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)1869 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1870 size_t offset, struct trace_probe *tp)
1871 {
1872 int ret, i;
1873
1874 /* Set argument names as fields */
1875 for (i = 0; i < tp->nr_args; i++) {
1876 struct probe_arg *parg = &tp->args[i];
1877 const char *fmt = parg->type->fmttype;
1878 int size = parg->type->size;
1879
1880 if (parg->fmt)
1881 fmt = parg->fmt;
1882 if (parg->count)
1883 size *= parg->count;
1884 ret = trace_define_field(event_call, fmt, parg->name,
1885 offset + parg->offset, size,
1886 parg->type->is_signed,
1887 FILTER_OTHER);
1888 if (ret)
1889 return ret;
1890 }
1891 return 0;
1892 }
1893
trace_probe_event_free(struct trace_probe_event * tpe)1894 static void trace_probe_event_free(struct trace_probe_event *tpe)
1895 {
1896 kfree(tpe->class.system);
1897 kfree(tpe->call.name);
1898 kfree(tpe->call.print_fmt);
1899 kfree(tpe);
1900 }
1901
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)1902 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1903 {
1904 if (trace_probe_has_sibling(tp))
1905 return -EBUSY;
1906
1907 list_del_init(&tp->list);
1908 trace_probe_event_free(tp->event);
1909
1910 tp->event = to->event;
1911 list_add_tail(&tp->list, trace_probe_probe_list(to));
1912
1913 return 0;
1914 }
1915
trace_probe_unlink(struct trace_probe * tp)1916 void trace_probe_unlink(struct trace_probe *tp)
1917 {
1918 list_del_init(&tp->list);
1919 if (list_empty(trace_probe_probe_list(tp)))
1920 trace_probe_event_free(tp->event);
1921 tp->event = NULL;
1922 }
1923
trace_probe_cleanup(struct trace_probe * tp)1924 void trace_probe_cleanup(struct trace_probe *tp)
1925 {
1926 int i;
1927
1928 for (i = 0; i < tp->nr_args; i++)
1929 traceprobe_free_probe_arg(&tp->args[i]);
1930
1931 if (tp->entry_arg) {
1932 kfree(tp->entry_arg->code);
1933 kfree(tp->entry_arg);
1934 tp->entry_arg = NULL;
1935 }
1936
1937 if (tp->event)
1938 trace_probe_unlink(tp);
1939 }
1940
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter,int nargs)1941 int trace_probe_init(struct trace_probe *tp, const char *event,
1942 const char *group, bool alloc_filter, int nargs)
1943 {
1944 struct trace_event_call *call;
1945 size_t size = sizeof(struct trace_probe_event);
1946 int ret = 0;
1947
1948 if (!event || !group)
1949 return -EINVAL;
1950
1951 if (alloc_filter)
1952 size += sizeof(struct trace_uprobe_filter);
1953
1954 tp->event = kzalloc(size, GFP_KERNEL);
1955 if (!tp->event)
1956 return -ENOMEM;
1957
1958 INIT_LIST_HEAD(&tp->event->files);
1959 INIT_LIST_HEAD(&tp->event->class.fields);
1960 INIT_LIST_HEAD(&tp->event->probes);
1961 INIT_LIST_HEAD(&tp->list);
1962 list_add(&tp->list, &tp->event->probes);
1963
1964 call = trace_probe_event_call(tp);
1965 call->class = &tp->event->class;
1966 call->name = kstrdup(event, GFP_KERNEL);
1967 if (!call->name) {
1968 ret = -ENOMEM;
1969 goto error;
1970 }
1971
1972 tp->event->class.system = kstrdup(group, GFP_KERNEL);
1973 if (!tp->event->class.system) {
1974 ret = -ENOMEM;
1975 goto error;
1976 }
1977
1978 tp->nr_args = nargs;
1979 /* Make sure pointers in args[] are NULL */
1980 if (nargs)
1981 memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
1982
1983 return 0;
1984
1985 error:
1986 trace_probe_cleanup(tp);
1987 return ret;
1988 }
1989
1990 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)1991 find_trace_event_call(const char *system, const char *event_name)
1992 {
1993 struct trace_event_call *tp_event;
1994 const char *name;
1995
1996 list_for_each_entry(tp_event, &ftrace_events, list) {
1997 if (!tp_event->class->system ||
1998 strcmp(system, tp_event->class->system))
1999 continue;
2000 name = trace_event_name(tp_event);
2001 if (!name || strcmp(event_name, name))
2002 continue;
2003 return tp_event;
2004 }
2005
2006 return NULL;
2007 }
2008
trace_probe_register_event_call(struct trace_probe * tp)2009 int trace_probe_register_event_call(struct trace_probe *tp)
2010 {
2011 struct trace_event_call *call = trace_probe_event_call(tp);
2012 int ret;
2013
2014 lockdep_assert_held(&event_mutex);
2015
2016 if (find_trace_event_call(trace_probe_group_name(tp),
2017 trace_probe_name(tp)))
2018 return -EEXIST;
2019
2020 ret = register_trace_event(&call->event);
2021 if (!ret)
2022 return -ENODEV;
2023
2024 ret = trace_add_event_call(call);
2025 if (ret)
2026 unregister_trace_event(&call->event);
2027
2028 return ret;
2029 }
2030
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)2031 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2032 {
2033 struct event_file_link *link;
2034
2035 link = kmalloc(sizeof(*link), GFP_KERNEL);
2036 if (!link)
2037 return -ENOMEM;
2038
2039 link->file = file;
2040 INIT_LIST_HEAD(&link->list);
2041 list_add_tail_rcu(&link->list, &tp->event->files);
2042 trace_probe_set_flag(tp, TP_FLAG_TRACE);
2043 return 0;
2044 }
2045
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)2046 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2047 struct trace_event_file *file)
2048 {
2049 struct event_file_link *link;
2050
2051 trace_probe_for_each_link(link, tp) {
2052 if (link->file == file)
2053 return link;
2054 }
2055
2056 return NULL;
2057 }
2058
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)2059 int trace_probe_remove_file(struct trace_probe *tp,
2060 struct trace_event_file *file)
2061 {
2062 struct event_file_link *link;
2063
2064 link = trace_probe_get_file_link(tp, file);
2065 if (!link)
2066 return -ENOENT;
2067
2068 list_del_rcu(&link->list);
2069 kvfree_rcu_mightsleep(link);
2070
2071 if (list_empty(&tp->event->files))
2072 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2073
2074 return 0;
2075 }
2076
2077 /*
2078 * Return the smallest index of different type argument (start from 1).
2079 * If all argument types and name are same, return 0.
2080 */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)2081 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2082 {
2083 int i;
2084
2085 /* In case of more arguments */
2086 if (a->nr_args < b->nr_args)
2087 return a->nr_args + 1;
2088 if (a->nr_args > b->nr_args)
2089 return b->nr_args + 1;
2090
2091 for (i = 0; i < a->nr_args; i++) {
2092 if ((b->nr_args <= i) ||
2093 ((a->args[i].type != b->args[i].type) ||
2094 (a->args[i].count != b->args[i].count) ||
2095 strcmp(a->args[i].name, b->args[i].name)))
2096 return i + 1;
2097 }
2098
2099 return 0;
2100 }
2101
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)2102 bool trace_probe_match_command_args(struct trace_probe *tp,
2103 int argc, const char **argv)
2104 {
2105 char buf[MAX_ARGSTR_LEN + 1];
2106 int i;
2107
2108 if (tp->nr_args < argc)
2109 return false;
2110
2111 for (i = 0; i < argc; i++) {
2112 snprintf(buf, sizeof(buf), "%s=%s",
2113 tp->args[i].name, tp->args[i].comm);
2114 if (strcmp(buf, argv[i]))
2115 return false;
2116 }
2117 return true;
2118 }
2119
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))2120 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2121 {
2122 int argc = 0, ret = 0;
2123 char **argv;
2124
2125 argv = argv_split(GFP_KERNEL, raw_command, &argc);
2126 if (!argv)
2127 return -ENOMEM;
2128
2129 if (argc)
2130 ret = createfn(argc, (const char **)argv);
2131
2132 argv_free(argv);
2133
2134 return ret;
2135 }
2136
trace_probe_print_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)2137 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2138 u8 *data, void *field)
2139 {
2140 void *p;
2141 int i, j;
2142
2143 for (i = 0; i < nr_args; i++) {
2144 struct probe_arg *a = args + i;
2145
2146 trace_seq_printf(s, " %s=", a->name);
2147 if (likely(!a->count)) {
2148 if (!a->type->print(s, data + a->offset, field))
2149 return -ENOMEM;
2150 continue;
2151 }
2152 trace_seq_putc(s, '{');
2153 p = data + a->offset;
2154 for (j = 0; j < a->count; j++) {
2155 if (!a->type->print(s, p, field))
2156 return -ENOMEM;
2157 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2158 p += a->type->size;
2159 }
2160 }
2161 return 0;
2162 }
2163