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 <linux/fs.h>
16
17 #include "trace_btf.h"
18 #include "trace_probe.h"
19
20 #undef C
21 #define C(a, b) b
22
23 static const char *trace_probe_err_text[] = { ERRORS };
24
25 static const char *reserved_field_names[] = {
26 "common_type",
27 "common_flags",
28 "common_preempt_count",
29 "common_pid",
30 "common_tgid",
31 FIELD_STRING_IP,
32 FIELD_STRING_RETIP,
33 FIELD_STRING_FUNC,
34 };
35
36 /* Printing in basic type function template */
37 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
38 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
39 { \
40 trace_seq_printf(s, fmt, *(type *)data); \
41 return !trace_seq_has_overflowed(s); \
42 } \
43 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
44
45 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
48 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
49 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
53 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
54 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
55 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
56 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
57 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
58
PRINT_TYPE_FUNC_NAME(symbol)59 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
60 {
61 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
62 return !trace_seq_has_overflowed(s);
63 }
64 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
65
66 /* Print type function for string type */
PRINT_TYPE_FUNC_NAME(string)67 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
68 {
69 int len = *(u32 *)data >> 16;
70
71 if (!len)
72 trace_seq_puts(s, FAULT_STRING);
73 else
74 trace_seq_printf(s, "\"%s\"",
75 (const char *)get_loc_data(data, ent));
76 return !trace_seq_has_overflowed(s);
77 }
78
79 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
80
81 /* Fetch type information table */
82 static const struct fetch_type probe_fetch_types[] = {
83 /* Special types */
84 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
85 "__data_loc char[]"),
86 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
87 "__data_loc char[]"),
88 __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
89 "__data_loc char[]"),
90 /* Basic types */
91 ASSIGN_FETCH_TYPE(u8, u8, 0),
92 ASSIGN_FETCH_TYPE(u16, u16, 0),
93 ASSIGN_FETCH_TYPE(u32, u32, 0),
94 ASSIGN_FETCH_TYPE(u64, u64, 0),
95 ASSIGN_FETCH_TYPE(s8, u8, 1),
96 ASSIGN_FETCH_TYPE(s16, u16, 1),
97 ASSIGN_FETCH_TYPE(s32, u32, 1),
98 ASSIGN_FETCH_TYPE(s64, u64, 1),
99 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
100 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
101 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
102 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
103 ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0),
104 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
105
106 ASSIGN_FETCH_TYPE_END
107 };
108
find_fetch_type(const char * type,unsigned long flags)109 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
110 {
111 int i;
112
113 /* Reject the symbol/symstr for uprobes */
114 if (type && (flags & TPARG_FL_USER) &&
115 (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
116 return NULL;
117
118 if (!type)
119 type = DEFAULT_FETCH_TYPE_STR;
120
121 /* Special case: bitfield */
122 if (*type == 'b') {
123 unsigned long bs;
124
125 type = strchr(type, '/');
126 if (!type)
127 goto fail;
128
129 type++;
130 if (kstrtoul(type, 0, &bs))
131 goto fail;
132
133 switch (bs) {
134 case 8:
135 return find_fetch_type("u8", flags);
136 case 16:
137 return find_fetch_type("u16", flags);
138 case 32:
139 return find_fetch_type("u32", flags);
140 case 64:
141 return find_fetch_type("u64", flags);
142 default:
143 goto fail;
144 }
145 }
146
147 for (i = 0; probe_fetch_types[i].name; i++) {
148 if (strcmp(type, probe_fetch_types[i].name) == 0)
149 return &probe_fetch_types[i];
150 }
151
152 fail:
153 return NULL;
154 }
155
156 static struct trace_probe_log trace_probe_log;
157 extern struct mutex dyn_event_ops_mutex;
158
trace_probe_log_init(const char * subsystem,int argc,const char ** argv)159 const char *trace_probe_log_init(const char *subsystem, int argc, const char **argv)
160 {
161 lockdep_assert_held(&dyn_event_ops_mutex);
162
163 trace_probe_log.subsystem = subsystem;
164 trace_probe_log.argc = argc;
165 trace_probe_log.argv = argv;
166 trace_probe_log.index = 0;
167 return subsystem;
168 }
169
trace_probe_log_clear(void)170 void trace_probe_log_clear(void)
171 {
172 lockdep_assert_held(&dyn_event_ops_mutex);
173
174 memset(&trace_probe_log, 0, sizeof(trace_probe_log));
175 }
176
trace_probe_log_set_index(int index)177 void trace_probe_log_set_index(int index)
178 {
179 lockdep_assert_held(&dyn_event_ops_mutex);
180
181 trace_probe_log.index = index;
182 }
183
__trace_probe_log_err(int offset,int err_type)184 void __trace_probe_log_err(int offset, int err_type)
185 {
186 char *command, *p;
187 int i, len = 0, pos = 0;
188
189 lockdep_assert_held(&dyn_event_ops_mutex);
190
191 if (!trace_probe_log.argv)
192 return;
193
194 /* Recalculate the length and allocate buffer */
195 for (i = 0; i < trace_probe_log.argc; i++) {
196 if (i == trace_probe_log.index)
197 pos = len;
198 len += strlen(trace_probe_log.argv[i]) + 1;
199 }
200 command = kzalloc(len, GFP_KERNEL);
201 if (!command)
202 return;
203
204 if (trace_probe_log.index >= trace_probe_log.argc) {
205 /**
206 * Set the error position is next to the last arg + space.
207 * Note that len includes the terminal null and the cursor
208 * appears at pos + 1.
209 */
210 pos = len;
211 offset = 0;
212 }
213
214 /* And make a command string from argv array */
215 p = command;
216 for (i = 0; i < trace_probe_log.argc; i++) {
217 len = strlen(trace_probe_log.argv[i]);
218 memcpy(p, trace_probe_log.argv[i], len);
219 p[len] = ' ';
220 p += len + 1;
221 }
222 *(p - 1) = '\0';
223
224 tracing_log_err(NULL, trace_probe_log.subsystem, command,
225 trace_probe_err_text, err_type, pos + offset);
226
227 kfree(command);
228 }
229
230 /* Split symbol and offset. */
traceprobe_split_symbol_offset(char * symbol,long * offset)231 int traceprobe_split_symbol_offset(char *symbol, long *offset)
232 {
233 char *tmp;
234 int ret;
235
236 if (!offset)
237 return -EINVAL;
238
239 tmp = strpbrk(symbol, "+-");
240 if (tmp) {
241 ret = kstrtol(tmp, 0, offset);
242 if (ret)
243 return ret;
244 *tmp = '\0';
245 } else
246 *offset = 0;
247
248 return 0;
249 }
250
251 /**
252 * traceprobe_parse_event_name() - Parse a string into group and event names
253 * @pevent: A pointer to the string to be parsed.
254 * @pgroup: A pointer to the group name.
255 * @buf: A buffer to store the parsed group name.
256 * @offset: The offset of the string in the original user command, for logging.
257 *
258 * This parses a string with the format `[GROUP/][EVENT]` or `[GROUP.][EVENT]`
259 * (either GROUP or EVENT or both must be specified).
260 * Since the parsed group name is stored in @buf, the caller must ensure @buf
261 * is at least MAX_EVENT_NAME_LEN bytes.
262 *
263 * Return: 0 on success, or -EINVAL on failure.
264 *
265 * If success, *@pevent is updated to point to the event name part of the
266 * original string, or NULL if there is no event name.
267 * Also, *@pgroup is updated to point to the parsed group which is stored
268 * in @buf, or NULL if there is no group name.
269 */
traceprobe_parse_event_name(const char ** pevent,const char ** pgroup,char * buf,int offset)270 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
271 char *buf, int offset)
272 {
273 const char *slash, *event = *pevent;
274 int len;
275
276 slash = strchr(event, '/');
277 if (!slash)
278 slash = strchr(event, '.');
279
280 if (slash) {
281 if (slash == event) {
282 trace_probe_log_err(offset, NO_GROUP_NAME);
283 return -EINVAL;
284 }
285 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
286 trace_probe_log_err(offset, GROUP_TOO_LONG);
287 return -EINVAL;
288 }
289 strscpy(buf, event, slash - event + 1);
290 if (!is_good_system_name(buf)) {
291 trace_probe_log_err(offset, BAD_GROUP_NAME);
292 return -EINVAL;
293 }
294 *pgroup = buf;
295 *pevent = slash + 1;
296 offset += slash - event + 1;
297 event = *pevent;
298 }
299 len = strlen(event);
300 if (len == 0) {
301 if (slash) {
302 *pevent = NULL;
303 return 0;
304 }
305 trace_probe_log_err(offset, NO_EVENT_NAME);
306 return -EINVAL;
307 } else if (len >= MAX_EVENT_NAME_LEN) {
308 trace_probe_log_err(offset, EVENT_TOO_LONG);
309 return -EINVAL;
310 }
311 if (!is_good_name(event)) {
312 trace_probe_log_err(offset, BAD_EVENT_NAME);
313 return -EINVAL;
314 }
315 return 0;
316 }
317
parse_trace_event_arg(char * arg,struct fetch_insn * code,struct traceprobe_parse_context * ctx)318 static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
319 struct traceprobe_parse_context *ctx)
320 {
321 struct ftrace_event_field *field;
322 struct list_head *head;
323
324 head = trace_get_fields(ctx->event);
325 list_for_each_entry(field, head, link) {
326 if (!strcmp(arg, field->name)) {
327 code->op = FETCH_OP_TP_ARG;
328 code->data = field;
329 return 0;
330 }
331 }
332 return -ENOENT;
333 }
334
335 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
336
btf_type_int(const struct btf_type * t)337 static u32 btf_type_int(const struct btf_type *t)
338 {
339 return *(u32 *)(t + 1);
340 }
341
btf_type_is_char_ptr(struct btf * btf,const struct btf_type * type)342 static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
343 {
344 const struct btf_type *real_type;
345 u32 intdata;
346 s32 tid;
347
348 real_type = btf_type_skip_modifiers(btf, type->type, &tid);
349 if (!real_type)
350 return false;
351
352 if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
353 return false;
354
355 intdata = btf_type_int(real_type);
356 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
357 && BTF_INT_BITS(intdata) == 8;
358 }
359
btf_type_is_char_array(struct btf * btf,const struct btf_type * type)360 static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
361 {
362 const struct btf_type *real_type;
363 const struct btf_array *array;
364 u32 intdata;
365 s32 tid;
366
367 if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
368 return false;
369
370 array = (const struct btf_array *)(type + 1);
371
372 real_type = btf_type_skip_modifiers(btf, array->type, &tid);
373
374 intdata = btf_type_int(real_type);
375 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
376 && BTF_INT_BITS(intdata) == 8;
377 }
378
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)379 static int check_prepare_btf_string_fetch(char *typename,
380 struct fetch_insn **pcode,
381 struct traceprobe_parse_context *ctx)
382 {
383 struct btf *btf = ctx->btf;
384
385 if (!btf || !ctx->last_type)
386 return 0;
387
388 /* char [] does not need any change. */
389 if (btf_type_is_char_array(btf, ctx->last_type))
390 return 0;
391
392 /* char * requires dereference the pointer. */
393 if (btf_type_is_char_ptr(btf, ctx->last_type)) {
394 struct fetch_insn *code = *pcode + 1;
395
396 if (code->op == FETCH_OP_END) {
397 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
398 return -E2BIG;
399 }
400 if (typename[0] == 'u')
401 code->op = FETCH_OP_UDEREF;
402 else
403 code->op = FETCH_OP_DEREF;
404 code->offset = 0;
405 *pcode = code;
406 return 0;
407 }
408 /* Other types are not available for string */
409 trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
410 return -EINVAL;
411 }
412
fetch_type_from_btf_type(struct btf * btf,const struct btf_type * type,struct traceprobe_parse_context * ctx)413 static const char *fetch_type_from_btf_type(struct btf *btf,
414 const struct btf_type *type,
415 struct traceprobe_parse_context *ctx)
416 {
417 u32 intdata;
418
419 /* TODO: const char * could be converted as a string */
420 switch (BTF_INFO_KIND(type->info)) {
421 case BTF_KIND_ENUM:
422 /* enum is "int", so convert to "s32" */
423 return "s32";
424 case BTF_KIND_ENUM64:
425 return "s64";
426 case BTF_KIND_PTR:
427 /* pointer will be converted to "x??" */
428 if (IS_ENABLED(CONFIG_64BIT))
429 return "x64";
430 else
431 return "x32";
432 case BTF_KIND_INT:
433 intdata = btf_type_int(type);
434 if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
435 switch (BTF_INT_BITS(intdata)) {
436 case 8:
437 return "s8";
438 case 16:
439 return "s16";
440 case 32:
441 return "s32";
442 case 64:
443 return "s64";
444 }
445 } else { /* unsigned */
446 switch (BTF_INT_BITS(intdata)) {
447 case 8:
448 return "u8";
449 case 16:
450 return "u16";
451 case 32:
452 return "u32";
453 case 64:
454 return "u64";
455 }
456 /* bitfield, size is encoded in the type */
457 ctx->last_bitsize = BTF_INT_BITS(intdata);
458 ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
459 return "u64";
460 }
461 }
462 /* TODO: support other types */
463
464 return NULL;
465 }
466
query_btf_context(struct traceprobe_parse_context * ctx)467 static int query_btf_context(struct traceprobe_parse_context *ctx)
468 {
469 const struct btf_param *param;
470 const struct btf_type *type;
471 struct btf *btf;
472 s32 nr;
473
474 if (ctx->btf)
475 return 0;
476
477 if (!ctx->funcname)
478 return -EINVAL;
479
480 type = btf_find_func_proto(ctx->funcname, &btf);
481 if (!type)
482 return -ENOENT;
483
484 ctx->btf = btf;
485 ctx->proto = type;
486
487 /* ctx->params is optional, since func(void) will not have params. */
488 nr = 0;
489 param = btf_get_func_param(type, &nr);
490 if (!IS_ERR_OR_NULL(param)) {
491 /* Hide the first 'data' argument of tracepoint */
492 if (ctx->flags & TPARG_FL_TPOINT) {
493 nr--;
494 param++;
495 }
496 }
497
498 if (nr > 0) {
499 ctx->nr_params = nr;
500 ctx->params = param;
501 } else {
502 ctx->nr_params = 0;
503 ctx->params = NULL;
504 }
505
506 return 0;
507 }
508
clear_btf_context(struct traceprobe_parse_context * ctx)509 static void clear_btf_context(struct traceprobe_parse_context *ctx)
510 {
511 if (ctx->btf) {
512 btf_put(ctx->btf);
513 ctx->btf = NULL;
514 ctx->proto = NULL;
515 ctx->params = NULL;
516 ctx->nr_params = 0;
517 }
518 }
519
520 /* Return 1 if the field separater is arrow operator ('->') */
split_next_field(char * varname,char ** next_field,struct traceprobe_parse_context * ctx)521 static int split_next_field(char *varname, char **next_field,
522 struct traceprobe_parse_context *ctx)
523 {
524 char *field;
525 int ret = 0;
526
527 field = strpbrk(varname, ".-");
528 if (field) {
529 if (field[0] == '-' && field[1] == '>') {
530 field[0] = '\0';
531 field += 2;
532 ret = 1;
533 } else if (field[0] == '.') {
534 field[0] = '\0';
535 field += 1;
536 } else {
537 trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
538 return -EINVAL;
539 }
540 *next_field = field;
541 }
542
543 return ret;
544 }
545
546 /*
547 * Parse the field of data structure. The @type must be a pointer type
548 * pointing the target data structure type.
549 */
parse_btf_field(char * fieldname,const struct btf_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)550 static int parse_btf_field(char *fieldname, const struct btf_type *type,
551 struct fetch_insn **pcode, struct fetch_insn *end,
552 struct traceprobe_parse_context *ctx)
553 {
554 struct fetch_insn *code = *pcode;
555 const struct btf_member *field;
556 u32 bitoffs, anon_offs;
557 char *next;
558 int is_ptr;
559 s32 tid;
560
561 do {
562 /* Outer loop for solving arrow operator ('->') */
563 if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
564 trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
565 return -EINVAL;
566 }
567 /* Convert a struct pointer type to a struct type */
568 type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
569 if (!type) {
570 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
571 return -EINVAL;
572 }
573
574 bitoffs = 0;
575 do {
576 /* Inner loop for solving dot operator ('.') */
577 next = NULL;
578 is_ptr = split_next_field(fieldname, &next, ctx);
579 if (is_ptr < 0)
580 return is_ptr;
581
582 anon_offs = 0;
583 field = btf_find_struct_member(ctx->btf, type, fieldname,
584 &anon_offs);
585 if (IS_ERR(field)) {
586 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
587 return PTR_ERR(field);
588 }
589 if (!field) {
590 trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
591 return -ENOENT;
592 }
593 /* Add anonymous structure/union offset */
594 bitoffs += anon_offs;
595
596 /* Accumulate the bit-offsets of the dot-connected fields */
597 if (btf_type_kflag(type)) {
598 bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
599 ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
600 } else {
601 bitoffs += field->offset;
602 ctx->last_bitsize = 0;
603 }
604
605 type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
606 if (!type) {
607 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
608 return -EINVAL;
609 }
610
611 ctx->offset += next - fieldname;
612 fieldname = next;
613 } while (!is_ptr && fieldname);
614
615 if (++code == end) {
616 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
617 return -EINVAL;
618 }
619 code->op = FETCH_OP_DEREF; /* TODO: user deref support */
620 code->offset = bitoffs / 8;
621 *pcode = code;
622
623 ctx->last_bitoffs = bitoffs % 8;
624 ctx->last_type = type;
625 } while (fieldname);
626
627 return 0;
628 }
629
630 static int __store_entry_arg(struct trace_probe *tp, int argnum);
631
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)632 static int parse_btf_arg(char *varname,
633 struct fetch_insn **pcode, struct fetch_insn *end,
634 struct traceprobe_parse_context *ctx)
635 {
636 struct fetch_insn *code = *pcode;
637 const struct btf_param *params;
638 const struct btf_type *type;
639 char *field = NULL;
640 int i, is_ptr, ret;
641 u32 tid;
642
643 if (WARN_ON_ONCE(!ctx->funcname))
644 return -EINVAL;
645
646 is_ptr = split_next_field(varname, &field, ctx);
647 if (is_ptr < 0)
648 return is_ptr;
649 if (!is_ptr && field) {
650 /* dot-connected field on an argument is not supported. */
651 trace_probe_log_err(ctx->offset + field - varname,
652 NOSUP_DAT_ARG);
653 return -EOPNOTSUPP;
654 }
655
656 if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
657 code->op = FETCH_OP_RETVAL;
658 /* Check whether the function return type is not void */
659 if (query_btf_context(ctx) == 0) {
660 if (ctx->proto->type == 0) {
661 trace_probe_log_err(ctx->offset, NO_RETVAL);
662 return -ENOENT;
663 }
664 tid = ctx->proto->type;
665 goto found;
666 }
667 if (field) {
668 trace_probe_log_err(ctx->offset + field - varname,
669 NO_BTF_ENTRY);
670 return -ENOENT;
671 }
672 return 0;
673 }
674
675 if (!ctx->btf) {
676 ret = query_btf_context(ctx);
677 if (ret < 0 || ctx->nr_params == 0) {
678 trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
679 return -ENOENT;
680 }
681 }
682 params = ctx->params;
683
684 for (i = 0; i < ctx->nr_params; i++) {
685 const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
686
687 if (name && !strcmp(name, varname)) {
688 if (tparg_is_function_entry(ctx->flags)) {
689 code->op = FETCH_OP_ARG;
690 if (ctx->flags & TPARG_FL_TPOINT)
691 code->param = i + 1;
692 else
693 code->param = i;
694 } else if (tparg_is_function_return(ctx->flags)) {
695 code->op = FETCH_OP_EDATA;
696 ret = __store_entry_arg(ctx->tp, i);
697 if (ret < 0) {
698 /* internal error */
699 return ret;
700 }
701 code->offset = ret;
702 }
703 tid = params[i].type;
704 goto found;
705 }
706 }
707 trace_probe_log_err(ctx->offset, NO_BTFARG);
708 return -ENOENT;
709
710 found:
711 type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
712 if (!type) {
713 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
714 return -EINVAL;
715 }
716 /* Initialize the last type information */
717 ctx->last_type = type;
718 ctx->last_bitoffs = 0;
719 ctx->last_bitsize = 0;
720 if (field) {
721 ctx->offset += field - varname;
722 return parse_btf_field(field, type, pcode, end, ctx);
723 }
724 return 0;
725 }
726
find_fetch_type_from_btf_type(struct traceprobe_parse_context * ctx)727 static const struct fetch_type *find_fetch_type_from_btf_type(
728 struct traceprobe_parse_context *ctx)
729 {
730 struct btf *btf = ctx->btf;
731 const char *typestr = NULL;
732
733 if (btf && ctx->last_type)
734 typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
735
736 return find_fetch_type(typestr, ctx->flags);
737 }
738
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)739 static int parse_btf_bitfield(struct fetch_insn **pcode,
740 struct traceprobe_parse_context *ctx)
741 {
742 struct fetch_insn *code = *pcode;
743
744 if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
745 return 0;
746
747 code++;
748 if (code->op != FETCH_OP_NOP) {
749 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
750 return -EINVAL;
751 }
752 *pcode = code;
753
754 code->op = FETCH_OP_MOD_BF;
755 code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
756 code->rshift = 64 - ctx->last_bitsize;
757 code->basesize = 64 / 8;
758 return 0;
759 }
760
761 #else
clear_btf_context(struct traceprobe_parse_context * ctx)762 static void clear_btf_context(struct traceprobe_parse_context *ctx)
763 {
764 ctx->btf = NULL;
765 }
766
query_btf_context(struct traceprobe_parse_context * ctx)767 static int query_btf_context(struct traceprobe_parse_context *ctx)
768 {
769 return -EOPNOTSUPP;
770 }
771
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)772 static int parse_btf_arg(char *varname,
773 struct fetch_insn **pcode, struct fetch_insn *end,
774 struct traceprobe_parse_context *ctx)
775 {
776 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
777 return -EOPNOTSUPP;
778 }
779
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)780 static int parse_btf_bitfield(struct fetch_insn **pcode,
781 struct traceprobe_parse_context *ctx)
782 {
783 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
784 return -EOPNOTSUPP;
785 }
786
787 #define find_fetch_type_from_btf_type(ctx) \
788 find_fetch_type(NULL, ctx->flags)
789
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)790 static int check_prepare_btf_string_fetch(char *typename,
791 struct fetch_insn **pcode,
792 struct traceprobe_parse_context *ctx)
793 {
794 return 0;
795 }
796
797 #endif
798
799 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
800
store_entry_arg_at(struct fetch_insn * code,int argnum,int offset)801 static void store_entry_arg_at(struct fetch_insn *code, int argnum, int offset)
802 {
803 code[0].op = FETCH_OP_ARG;
804 code[0].param = argnum;
805 code[1].op = FETCH_OP_ST_EDATA;
806 code[1].offset = offset;
807 }
808
get_entry_arg_max_offset(struct probe_entry_arg * earg)809 static int get_entry_arg_max_offset(struct probe_entry_arg *earg)
810 {
811 int i, max_offset = 0;
812
813 /*
814 * earg->code[] array has an operation sequence which is run in
815 * the entry handler.
816 * The sequence stopped by FETCH_OP_END and each data stored in
817 * the entry data buffer by FETCH_OP_ST_EDATA. The FETCH_OP_ST_EDATA
818 * stores the data at the data buffer + its offset, and all data are
819 * "unsigned long" size. The offset must be increased when a data is
820 * stored. Thus we need to find the last FETCH_OP_ST_EDATA in the
821 * code array.
822 */
823 for (i = 0; i < earg->size - 1 && earg->code[i].op != FETCH_OP_END; i++) {
824 if (earg->code[i].op == FETCH_OP_ST_EDATA)
825 if (earg->code[i].offset > max_offset)
826 max_offset = earg->code[i].offset;
827 }
828 return max_offset;
829 }
830
831 /*
832 * Add the entry code to store the 'argnum'th parameter and return the offset
833 * in the entry data buffer where the data will be stored.
834 */
__store_entry_arg(struct trace_probe * tp,int argnum)835 static int __store_entry_arg(struct trace_probe *tp, int argnum)
836 {
837 struct probe_entry_arg *earg = tp->entry_arg;
838 int i, offset, last_offset = 0;
839
840 if (!earg) {
841 earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL);
842 if (!earg)
843 return -ENOMEM;
844 earg->size = 2 * tp->nr_args + 1;
845 earg->code = kcalloc(earg->size, sizeof(struct fetch_insn),
846 GFP_KERNEL);
847 if (!earg->code) {
848 kfree(earg);
849 return -ENOMEM;
850 }
851 /* Fill the code buffer with 'end' to simplify it */
852 for (i = 0; i < earg->size; i++)
853 earg->code[i].op = FETCH_OP_END;
854 tp->entry_arg = earg;
855 store_entry_arg_at(earg->code, argnum, 0);
856 return 0;
857 }
858
859 /*
860 * NOTE: if anyone change the following rule, please rewrite this.
861 * The entry code array is filled with the pair of
862 *
863 * [FETCH_OP_ARG(argnum)]
864 * [FETCH_OP_ST_EDATA(offset of entry data buffer)]
865 *
866 * and the rest of entries are filled with [FETCH_OP_END].
867 * The offset should be incremented, thus the last pair should
868 * have the largest offset.
869 */
870
871 /* Search the offset for the sprcified argnum. */
872 for (i = 0; i < earg->size - 1 && earg->code[i].op != FETCH_OP_END; i += 2) {
873 if (WARN_ON_ONCE(earg->code[i].op != FETCH_OP_ARG))
874 return -EINVAL;
875
876 if (earg->code[i].param != argnum)
877 continue;
878
879 if (WARN_ON_ONCE(earg->code[i + 1].op != FETCH_OP_ST_EDATA))
880 return -EINVAL;
881
882 return earg->code[i + 1].offset;
883 }
884 /* Not found, append new entry if possible. */
885 if (i >= earg->size - 1)
886 return -ENOSPC;
887
888 /* The last entry must have the largest offset. */
889 if (i != 0) {
890 if (WARN_ON_ONCE(earg->code[i - 1].op != FETCH_OP_ST_EDATA))
891 return -EINVAL;
892 last_offset = earg->code[i - 1].offset;
893 }
894
895 offset = last_offset + sizeof(unsigned long);
896 store_entry_arg_at(&earg->code[i], argnum, offset);
897 return offset;
898 }
899
traceprobe_get_entry_data_size(struct trace_probe * tp)900 int traceprobe_get_entry_data_size(struct trace_probe *tp)
901 {
902 struct probe_entry_arg *earg = tp->entry_arg;
903
904 if (!earg)
905 return 0;
906
907 return get_entry_arg_max_offset(earg) + sizeof(unsigned long);
908 }
909
store_trace_entry_data(void * edata,struct trace_probe * tp,struct pt_regs * regs)910 void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
911 {
912 struct probe_entry_arg *earg = tp->entry_arg;
913 unsigned long val = 0;
914 int i;
915
916 if (!earg)
917 return;
918
919 for (i = 0; i < earg->size; i++) {
920 struct fetch_insn *code = &earg->code[i];
921
922 switch (code->op) {
923 case FETCH_OP_ARG:
924 val = regs_get_kernel_argument(regs, code->param);
925 break;
926 case FETCH_OP_ST_EDATA:
927 *(unsigned long *)((unsigned long)edata + code->offset) = val;
928 break;
929 case FETCH_OP_END:
930 goto end;
931 default:
932 break;
933 }
934 }
935 end:
936 return;
937 }
NOKPROBE_SYMBOL(store_trace_entry_data)938 NOKPROBE_SYMBOL(store_trace_entry_data)
939 #endif
940
941 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
942
943 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
944 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
945 struct fetch_insn **pcode,
946 struct fetch_insn *end,
947 struct traceprobe_parse_context *ctx)
948 {
949 struct fetch_insn *code = *pcode;
950 int err = TP_ERR_BAD_VAR;
951 char *arg = orig_arg + 1;
952 unsigned long param;
953 int ret = 0;
954 int len;
955
956 if (ctx->flags & TPARG_FL_TEVENT) {
957 if (code->data)
958 return -EFAULT;
959 ret = parse_trace_event_arg(arg, code, ctx);
960 if (!ret)
961 return 0;
962 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
963 code->op = FETCH_OP_COMM;
964 return 0;
965 }
966 /* backward compatibility */
967 ctx->offset = 0;
968 goto inval;
969 }
970
971 if (str_has_prefix(arg, "retval")) {
972 if (!(ctx->flags & TPARG_FL_RETURN)) {
973 err = TP_ERR_RETVAL_ON_PROBE;
974 goto inval;
975 }
976 if (!(ctx->flags & TPARG_FL_KERNEL) ||
977 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
978 code->op = FETCH_OP_RETVAL;
979 return 0;
980 }
981 return parse_btf_arg(orig_arg, pcode, end, ctx);
982 }
983
984 len = str_has_prefix(arg, "stack");
985 if (len) {
986
987 if (arg[len] == '\0') {
988 code->op = FETCH_OP_STACKP;
989 return 0;
990 }
991
992 if (isdigit(arg[len])) {
993 ret = kstrtoul(arg + len, 10, ¶m);
994 if (ret)
995 goto inval;
996
997 if ((ctx->flags & TPARG_FL_KERNEL) &&
998 param > PARAM_MAX_STACK) {
999 err = TP_ERR_BAD_STACK_NUM;
1000 goto inval;
1001 }
1002 code->op = FETCH_OP_STACK;
1003 code->param = (unsigned int)param;
1004 return 0;
1005 }
1006 goto inval;
1007 }
1008
1009 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
1010 code->op = FETCH_OP_COMM;
1011 return 0;
1012 }
1013
1014 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1015 len = str_has_prefix(arg, "arg");
1016 if (len) {
1017 ret = kstrtoul(arg + len, 10, ¶m);
1018 if (ret)
1019 goto inval;
1020
1021 if (!param || param > PARAM_MAX_STACK) {
1022 err = TP_ERR_BAD_ARG_NUM;
1023 goto inval;
1024 }
1025 param--; /* argN starts from 1, but internal arg[N] starts from 0 */
1026
1027 if (tparg_is_function_entry(ctx->flags)) {
1028 code->op = FETCH_OP_ARG;
1029 code->param = (unsigned int)param;
1030 /*
1031 * The tracepoint probe will probe a stub function, and the
1032 * first parameter of the stub is a dummy and should be ignored.
1033 */
1034 if (ctx->flags & TPARG_FL_TPOINT)
1035 code->param++;
1036 } else if (tparg_is_function_return(ctx->flags)) {
1037 /* function entry argument access from return probe */
1038 ret = __store_entry_arg(ctx->tp, param);
1039 if (ret < 0) /* This error should be an internal error */
1040 return ret;
1041
1042 code->op = FETCH_OP_EDATA;
1043 code->offset = ret;
1044 } else {
1045 err = TP_ERR_NOFENTRY_ARGS;
1046 goto inval;
1047 }
1048 return 0;
1049 }
1050 #endif
1051
1052 inval:
1053 __trace_probe_log_err(ctx->offset, err);
1054 return -EINVAL;
1055 }
1056
str_to_immediate(char * str,unsigned long * imm)1057 static int str_to_immediate(char *str, unsigned long *imm)
1058 {
1059 if (isdigit(str[0]))
1060 return kstrtoul(str, 0, imm);
1061 else if (str[0] == '-')
1062 return kstrtol(str, 0, (long *)imm);
1063 else if (str[0] == '+')
1064 return kstrtol(str + 1, 0, (long *)imm);
1065 return -EINVAL;
1066 }
1067
__parse_imm_string(char * str,char ** pbuf,int offs)1068 static int __parse_imm_string(char *str, char **pbuf, int offs)
1069 {
1070 size_t len = strlen(str);
1071
1072 if (str[len - 1] != '"') {
1073 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1074 return -EINVAL;
1075 }
1076 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1077 if (!*pbuf)
1078 return -ENOMEM;
1079 return 0;
1080 }
1081
1082 /* Recursive argument parser */
1083 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)1084 parse_probe_arg(char *arg, const struct fetch_type *type,
1085 struct fetch_insn **pcode, struct fetch_insn *end,
1086 struct traceprobe_parse_context *ctx)
1087 {
1088 struct fetch_insn *code = *pcode;
1089 unsigned long param;
1090 int deref = FETCH_OP_DEREF;
1091 long offset = 0;
1092 char *tmp;
1093 int ret = 0;
1094
1095 switch (arg[0]) {
1096 case '$':
1097 ret = parse_probe_vars(arg, type, pcode, end, ctx);
1098 break;
1099
1100 case '%': /* named register */
1101 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1102 /* eprobe and fprobe do not handle registers */
1103 trace_probe_log_err(ctx->offset, BAD_VAR);
1104 break;
1105 }
1106 ret = regs_query_register_offset(arg + 1);
1107 if (ret >= 0) {
1108 code->op = FETCH_OP_REG;
1109 code->param = (unsigned int)ret;
1110 ret = 0;
1111 } else
1112 trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1113 break;
1114
1115 case '@': /* memory, file-offset or symbol */
1116 if (isdigit(arg[1])) {
1117 ret = kstrtoul(arg + 1, 0, ¶m);
1118 if (ret) {
1119 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1120 break;
1121 }
1122 /* load address */
1123 code->op = FETCH_OP_IMM;
1124 code->immediate = param;
1125 } else if (arg[1] == '+') {
1126 /* kprobes don't support file offsets */
1127 if (ctx->flags & TPARG_FL_KERNEL) {
1128 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1129 return -EINVAL;
1130 }
1131 ret = kstrtol(arg + 2, 0, &offset);
1132 if (ret) {
1133 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1134 break;
1135 }
1136
1137 code->op = FETCH_OP_FOFFS;
1138 code->immediate = (unsigned long)offset; // imm64?
1139 } else {
1140 /* uprobes don't support symbols */
1141 if (!(ctx->flags & TPARG_FL_KERNEL)) {
1142 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1143 return -EINVAL;
1144 }
1145 /* Preserve symbol for updating */
1146 code->op = FETCH_NOP_SYMBOL;
1147 code->data = kstrdup(arg + 1, GFP_KERNEL);
1148 if (!code->data)
1149 return -ENOMEM;
1150 if (++code == end) {
1151 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1152 return -EINVAL;
1153 }
1154 code->op = FETCH_OP_IMM;
1155 code->immediate = 0;
1156 }
1157 /* These are fetching from memory */
1158 if (++code == end) {
1159 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1160 return -EINVAL;
1161 }
1162 *pcode = code;
1163 code->op = FETCH_OP_DEREF;
1164 code->offset = offset;
1165 break;
1166
1167 case '+': /* deref memory */
1168 case '-':
1169 if (arg[1] == 'u') {
1170 deref = FETCH_OP_UDEREF;
1171 arg[1] = arg[0];
1172 arg++;
1173 }
1174 if (arg[0] == '+')
1175 arg++; /* Skip '+', because kstrtol() rejects it. */
1176 tmp = strchr(arg, '(');
1177 if (!tmp) {
1178 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1179 return -EINVAL;
1180 }
1181 *tmp = '\0';
1182 ret = kstrtol(arg, 0, &offset);
1183 if (ret) {
1184 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1185 break;
1186 }
1187 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1188 arg = tmp + 1;
1189 tmp = strrchr(arg, ')');
1190 if (!tmp) {
1191 trace_probe_log_err(ctx->offset + strlen(arg),
1192 DEREF_OPEN_BRACE);
1193 return -EINVAL;
1194 } else {
1195 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1196 int cur_offs = ctx->offset;
1197
1198 *tmp = '\0';
1199 ret = parse_probe_arg(arg, t2, &code, end, ctx);
1200 if (ret)
1201 break;
1202 ctx->offset = cur_offs;
1203 if (code->op == FETCH_OP_COMM ||
1204 code->op == FETCH_OP_DATA) {
1205 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1206 return -EINVAL;
1207 }
1208 if (++code == end) {
1209 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1210 return -EINVAL;
1211 }
1212 *pcode = code;
1213
1214 code->op = deref;
1215 code->offset = offset;
1216 /* Reset the last type if used */
1217 ctx->last_type = NULL;
1218 }
1219 break;
1220 case '\\': /* Immediate value */
1221 if (arg[1] == '"') { /* Immediate string */
1222 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1223 if (ret)
1224 break;
1225 code->op = FETCH_OP_DATA;
1226 code->data = tmp;
1227 } else {
1228 ret = str_to_immediate(arg + 1, &code->immediate);
1229 if (ret)
1230 trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1231 else
1232 code->op = FETCH_OP_IMM;
1233 }
1234 break;
1235 default:
1236 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
1237 if (!tparg_is_function_entry(ctx->flags) &&
1238 !tparg_is_function_return(ctx->flags)) {
1239 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1240 return -EINVAL;
1241 }
1242 ret = parse_btf_arg(arg, pcode, end, ctx);
1243 break;
1244 }
1245 }
1246 if (!ret && code->op == FETCH_OP_NOP) {
1247 /* Parsed, but do not find fetch method */
1248 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1249 ret = -EINVAL;
1250 }
1251 return ret;
1252 }
1253
1254 /* 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)1255 static int __parse_bitfield_probe_arg(const char *bf,
1256 const struct fetch_type *t,
1257 struct fetch_insn **pcode)
1258 {
1259 struct fetch_insn *code = *pcode;
1260 unsigned long bw, bo;
1261 char *tail;
1262
1263 if (*bf != 'b')
1264 return 0;
1265
1266 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
1267
1268 if (bw == 0 || *tail != '@')
1269 return -EINVAL;
1270
1271 bf = tail + 1;
1272 bo = simple_strtoul(bf, &tail, 0);
1273
1274 if (tail == bf || *tail != '/')
1275 return -EINVAL;
1276 code++;
1277 if (code->op != FETCH_OP_NOP)
1278 return -EINVAL;
1279 *pcode = code;
1280
1281 code->op = FETCH_OP_MOD_BF;
1282 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1283 code->rshift = BYTES_TO_BITS(t->size) - bw;
1284 code->basesize = t->size;
1285
1286 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1287 }
1288
1289 /* Split type part from @arg and return it. */
parse_probe_arg_type(char * arg,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1290 static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
1291 struct traceprobe_parse_context *ctx)
1292 {
1293 char *t = NULL, *t2, *t3;
1294 int offs;
1295
1296 t = strchr(arg, ':');
1297 if (t) {
1298 *t++ = '\0';
1299 t2 = strchr(t, '[');
1300 if (t2) {
1301 *t2++ = '\0';
1302 t3 = strchr(t2, ']');
1303 if (!t3) {
1304 offs = t2 + strlen(t2) - arg;
1305
1306 trace_probe_log_err(ctx->offset + offs,
1307 ARRAY_NO_CLOSE);
1308 return ERR_PTR(-EINVAL);
1309 } else if (t3[1] != '\0') {
1310 trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1311 BAD_ARRAY_SUFFIX);
1312 return ERR_PTR(-EINVAL);
1313 }
1314 *t3 = '\0';
1315 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1316 trace_probe_log_err(ctx->offset + t2 - arg,
1317 BAD_ARRAY_NUM);
1318 return ERR_PTR(-EINVAL);
1319 }
1320 if (parg->count > MAX_ARRAY_LEN) {
1321 trace_probe_log_err(ctx->offset + t2 - arg,
1322 ARRAY_TOO_BIG);
1323 return ERR_PTR(-EINVAL);
1324 }
1325 }
1326 }
1327 offs = t ? t - arg : 0;
1328
1329 /*
1330 * Since $comm and immediate string can not be dereferenced,
1331 * we can find those by strcmp. But ignore for eprobes.
1332 */
1333 if (!(ctx->flags & TPARG_FL_TEVENT) &&
1334 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1335 strncmp(arg, "\\\"", 2) == 0)) {
1336 /* The type of $comm must be "string", and not an array type. */
1337 if (parg->count || (t && strcmp(t, "string"))) {
1338 trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
1339 return ERR_PTR(-EINVAL);
1340 }
1341 parg->type = find_fetch_type("string", ctx->flags);
1342 } else
1343 parg->type = find_fetch_type(t, ctx->flags);
1344
1345 if (!parg->type) {
1346 trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
1347 return ERR_PTR(-EINVAL);
1348 }
1349
1350 return t;
1351 }
1352
1353 /* After parsing, adjust the fetch_insn according to the probe_arg */
finalize_fetch_insn(struct fetch_insn * code,struct probe_arg * parg,char * type,int type_offset,struct traceprobe_parse_context * ctx)1354 static int finalize_fetch_insn(struct fetch_insn *code,
1355 struct probe_arg *parg,
1356 char *type,
1357 int type_offset,
1358 struct traceprobe_parse_context *ctx)
1359 {
1360 struct fetch_insn *scode;
1361 int ret;
1362
1363 /* Store operation */
1364 if (parg->type->is_string) {
1365 /* Check bad combination of the type and the last fetch_insn. */
1366 if (!strcmp(parg->type->name, "symstr")) {
1367 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1368 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1369 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1370 trace_probe_log_err(ctx->offset + type_offset,
1371 BAD_SYMSTRING);
1372 return -EINVAL;
1373 }
1374 } else {
1375 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1376 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1377 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1378 trace_probe_log_err(ctx->offset + type_offset,
1379 BAD_STRING);
1380 return -EINVAL;
1381 }
1382 }
1383
1384 if (!strcmp(parg->type->name, "symstr") ||
1385 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1386 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1387 parg->count) {
1388 /*
1389 * IMM, DATA and COMM is pointing actual address, those
1390 * must be kept, and if parg->count != 0, this is an
1391 * array of string pointers instead of string address
1392 * itself.
1393 * For the symstr, it doesn't need to dereference, thus
1394 * it just get the value.
1395 */
1396 code++;
1397 if (code->op != FETCH_OP_NOP) {
1398 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1399 return -EINVAL;
1400 }
1401 }
1402
1403 /* If op == DEREF, replace it with STRING */
1404 if (!strcmp(parg->type->name, "ustring") ||
1405 code->op == FETCH_OP_UDEREF)
1406 code->op = FETCH_OP_ST_USTRING;
1407 else if (!strcmp(parg->type->name, "symstr"))
1408 code->op = FETCH_OP_ST_SYMSTR;
1409 else
1410 code->op = FETCH_OP_ST_STRING;
1411 code->size = parg->type->size;
1412 parg->dynamic = true;
1413 } else if (code->op == FETCH_OP_DEREF) {
1414 code->op = FETCH_OP_ST_MEM;
1415 code->size = parg->type->size;
1416 } else if (code->op == FETCH_OP_UDEREF) {
1417 code->op = FETCH_OP_ST_UMEM;
1418 code->size = parg->type->size;
1419 } else {
1420 code++;
1421 if (code->op != FETCH_OP_NOP) {
1422 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1423 return -E2BIG;
1424 }
1425 code->op = FETCH_OP_ST_RAW;
1426 code->size = parg->type->size;
1427 }
1428
1429 /* Save storing fetch_insn. */
1430 scode = code;
1431
1432 /* Modify operation */
1433 if (type != NULL) {
1434 /* Bitfield needs a special fetch_insn. */
1435 ret = __parse_bitfield_probe_arg(type, parg->type, &code);
1436 if (ret) {
1437 trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
1438 return ret;
1439 }
1440 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1441 ctx->last_type) {
1442 /* If user not specified the type, try parsing BTF bitfield. */
1443 ret = parse_btf_bitfield(&code, ctx);
1444 if (ret)
1445 return ret;
1446 }
1447
1448 /* Loop(Array) operation */
1449 if (parg->count) {
1450 if (scode->op != FETCH_OP_ST_MEM &&
1451 scode->op != FETCH_OP_ST_STRING &&
1452 scode->op != FETCH_OP_ST_USTRING) {
1453 trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
1454 return -EINVAL;
1455 }
1456 code++;
1457 if (code->op != FETCH_OP_NOP) {
1458 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1459 return -E2BIG;
1460 }
1461 code->op = FETCH_OP_LP_ARRAY;
1462 code->param = parg->count;
1463 }
1464
1465 /* Finalize the fetch_insn array. */
1466 code++;
1467 code->op = FETCH_OP_END;
1468
1469 return 0;
1470 }
1471
1472 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1473 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1474 struct probe_arg *parg,
1475 struct traceprobe_parse_context *ctx)
1476 {
1477 struct fetch_insn *code, *tmp = NULL;
1478 char *type, *arg __free(kfree) = NULL;
1479 int ret, len;
1480
1481 len = strlen(argv);
1482 if (len > MAX_ARGSTR_LEN) {
1483 trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1484 return -E2BIG;
1485 } else if (len == 0) {
1486 trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1487 return -EINVAL;
1488 }
1489
1490 arg = kstrdup(argv, GFP_KERNEL);
1491 if (!arg)
1492 return -ENOMEM;
1493
1494 parg->comm = kstrdup(arg, GFP_KERNEL);
1495 if (!parg->comm)
1496 return -ENOMEM;
1497
1498 type = parse_probe_arg_type(arg, parg, ctx);
1499 if (IS_ERR(type))
1500 return PTR_ERR(type);
1501
1502 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
1503 if (!code)
1504 return -ENOMEM;
1505 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1506
1507 ctx->last_type = NULL;
1508 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1509 ctx);
1510 if (ret < 0)
1511 goto fail;
1512
1513 /* Update storing type if BTF is available */
1514 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1515 ctx->last_type) {
1516 if (!type) {
1517 parg->type = find_fetch_type_from_btf_type(ctx);
1518 } else if (strstr(type, "string")) {
1519 ret = check_prepare_btf_string_fetch(type, &code, ctx);
1520 if (ret)
1521 goto fail;
1522 }
1523 }
1524 parg->offset = *size;
1525 *size += parg->type->size * (parg->count ?: 1);
1526
1527 if (parg->count) {
1528 len = strlen(parg->type->fmttype) + 6;
1529 parg->fmt = kmalloc(len, GFP_KERNEL);
1530 if (!parg->fmt) {
1531 ret = -ENOMEM;
1532 goto fail;
1533 }
1534 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1535 parg->count);
1536 }
1537
1538 ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
1539 if (ret < 0)
1540 goto fail;
1541
1542 for (; code < tmp + FETCH_INSN_MAX; code++)
1543 if (code->op == FETCH_OP_END)
1544 break;
1545 /* Shrink down the code buffer */
1546 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1547 if (!parg->code)
1548 ret = -ENOMEM;
1549 else
1550 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1551
1552 fail:
1553 if (ret < 0) {
1554 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1555 if (code->op == FETCH_NOP_SYMBOL ||
1556 code->op == FETCH_OP_DATA)
1557 kfree(code->data);
1558 }
1559 kfree(tmp);
1560
1561 return ret;
1562 }
1563
1564 /* 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)1565 static int traceprobe_conflict_field_name(const char *name,
1566 struct probe_arg *args, int narg)
1567 {
1568 int i;
1569
1570 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1571 if (strcmp(reserved_field_names[i], name) == 0)
1572 return 1;
1573
1574 for (i = 0; i < narg; i++)
1575 if (strcmp(args[i].name, name) == 0)
1576 return 1;
1577
1578 return 0;
1579 }
1580
generate_probe_arg_name(const char * arg,int idx)1581 static char *generate_probe_arg_name(const char *arg, int idx)
1582 {
1583 char *name = NULL;
1584 const char *end;
1585
1586 /*
1587 * If argument name is omitted, try arg as a name (BTF variable)
1588 * or "argN".
1589 */
1590 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1591 end = strchr(arg, ':');
1592 if (!end)
1593 end = arg + strlen(arg);
1594
1595 name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1596 if (!name || !is_good_name(name)) {
1597 kfree(name);
1598 name = NULL;
1599 }
1600 }
1601
1602 if (!name)
1603 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1604
1605 return name;
1606 }
1607
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,struct traceprobe_parse_context * ctx)1608 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1609 struct traceprobe_parse_context *ctx)
1610 {
1611 struct probe_arg *parg = &tp->args[i];
1612 const char *body;
1613
1614 ctx->tp = tp;
1615 body = strchr(arg, '=');
1616 if (body) {
1617 if (body - arg > MAX_ARG_NAME_LEN) {
1618 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1619 return -EINVAL;
1620 } else if (body == arg) {
1621 trace_probe_log_err(0, NO_ARG_NAME);
1622 return -EINVAL;
1623 }
1624 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1625 body++;
1626 } else {
1627 parg->name = generate_probe_arg_name(arg, i);
1628 body = arg;
1629 }
1630 if (!parg->name)
1631 return -ENOMEM;
1632
1633 if (!is_good_name(parg->name)) {
1634 trace_probe_log_err(0, BAD_ARG_NAME);
1635 return -EINVAL;
1636 }
1637 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1638 trace_probe_log_err(0, USED_ARG_NAME);
1639 return -EINVAL;
1640 }
1641 ctx->offset = body - arg;
1642 /* Parse fetch argument */
1643 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1644 }
1645
traceprobe_free_probe_arg(struct probe_arg * arg)1646 void traceprobe_free_probe_arg(struct probe_arg *arg)
1647 {
1648 struct fetch_insn *code = arg->code;
1649
1650 while (code && code->op != FETCH_OP_END) {
1651 if (code->op == FETCH_NOP_SYMBOL ||
1652 code->op == FETCH_OP_DATA)
1653 kfree(code->data);
1654 code++;
1655 }
1656 kfree(arg->code);
1657 kfree(arg->name);
1658 kfree(arg->comm);
1659 kfree(arg->fmt);
1660 }
1661
argv_has_var_arg(int argc,const char * argv[],int * args_idx,struct traceprobe_parse_context * ctx)1662 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1663 struct traceprobe_parse_context *ctx)
1664 {
1665 int i, found = 0;
1666
1667 for (i = 0; i < argc; i++)
1668 if (str_has_prefix(argv[i], "$arg")) {
1669 trace_probe_log_set_index(i + 2);
1670
1671 if (!tparg_is_function_entry(ctx->flags) &&
1672 !tparg_is_function_return(ctx->flags)) {
1673 trace_probe_log_err(0, NOFENTRY_ARGS);
1674 return -EINVAL;
1675 }
1676
1677 if (isdigit(argv[i][4])) {
1678 found = 1;
1679 continue;
1680 }
1681
1682 if (argv[i][4] != '*') {
1683 trace_probe_log_err(0, BAD_VAR);
1684 return -EINVAL;
1685 }
1686
1687 if (*args_idx >= 0 && *args_idx < argc) {
1688 trace_probe_log_err(0, DOUBLE_ARGS);
1689 return -EINVAL;
1690 }
1691 found = 1;
1692 *args_idx = i;
1693 }
1694
1695 return found;
1696 }
1697
sprint_nth_btf_arg(int idx,const char * type,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1698 static int sprint_nth_btf_arg(int idx, const char *type,
1699 char *buf, int bufsize,
1700 struct traceprobe_parse_context *ctx)
1701 {
1702 const char *name;
1703 int ret;
1704
1705 if (idx >= ctx->nr_params) {
1706 trace_probe_log_err(0, NO_BTFARG);
1707 return -ENOENT;
1708 }
1709 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1710 if (!name) {
1711 trace_probe_log_err(0, NO_BTF_ENTRY);
1712 return -ENOENT;
1713 }
1714 ret = snprintf(buf, bufsize, "%s%s", name, type);
1715 if (ret >= bufsize) {
1716 trace_probe_log_err(0, ARGS_2LONG);
1717 return -E2BIG;
1718 }
1719 return ret;
1720 }
1721
1722 /* 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)1723 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1724 int *new_argc, char *buf, int bufsize,
1725 struct traceprobe_parse_context *ctx)
1726 {
1727 const struct btf_param *params = NULL;
1728 int i, j, n, used, ret, args_idx = -1;
1729 const char **new_argv __free(kfree) = NULL;
1730
1731 ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1732 if (ret < 0)
1733 return ERR_PTR(ret);
1734
1735 if (!ret) {
1736 *new_argc = argc;
1737 return NULL;
1738 }
1739
1740 ret = query_btf_context(ctx);
1741 if (ret < 0 || ctx->nr_params == 0) {
1742 if (args_idx != -1) {
1743 /* $arg* requires BTF info */
1744 trace_probe_log_err(0, NOSUP_BTFARG);
1745 return (const char **)params;
1746 }
1747 *new_argc = argc;
1748 return NULL;
1749 }
1750
1751 if (args_idx >= 0)
1752 *new_argc = argc + ctx->nr_params - 1;
1753 else
1754 *new_argc = argc;
1755
1756 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1757 if (!new_argv)
1758 return ERR_PTR(-ENOMEM);
1759
1760 used = 0;
1761 for (i = 0, j = 0; i < argc; i++) {
1762 trace_probe_log_set_index(i + 2);
1763 if (i == args_idx) {
1764 for (n = 0; n < ctx->nr_params; n++) {
1765 ret = sprint_nth_btf_arg(n, "", buf + used,
1766 bufsize - used, ctx);
1767 if (ret < 0)
1768 return ERR_PTR(ret);
1769
1770 new_argv[j++] = buf + used;
1771 used += ret + 1;
1772 }
1773 continue;
1774 }
1775
1776 if (str_has_prefix(argv[i], "$arg")) {
1777 char *type = NULL;
1778
1779 n = simple_strtoul(argv[i] + 4, &type, 10);
1780 if (type && !(*type == ':' || *type == '\0')) {
1781 trace_probe_log_err(0, BAD_VAR);
1782 return ERR_PTR(-ENOENT);
1783 }
1784 /* Note: $argN starts from $arg1 */
1785 ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1786 bufsize - used, ctx);
1787 if (ret < 0)
1788 return ERR_PTR(ret);
1789 new_argv[j++] = buf + used;
1790 used += ret + 1;
1791 } else
1792 new_argv[j++] = argv[i];
1793 }
1794
1795 return_ptr(new_argv);
1796 }
1797
1798 /* @buf: *buf must be equal to NULL. Caller must to free *buf */
traceprobe_expand_dentry_args(int argc,const char * argv[],char ** buf)1799 int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
1800 {
1801 int i, used, ret;
1802 const int bufsize = MAX_DENTRY_ARGS_LEN;
1803 char *tmpbuf __free(kfree) = NULL;
1804
1805 if (*buf)
1806 return -EINVAL;
1807
1808 used = 0;
1809 for (i = 0; i < argc; i++) {
1810 char *tmp __free(kfree) = NULL;
1811 char *equal;
1812 size_t arg_len;
1813
1814 if (!glob_match("*:%p[dD]", argv[i]))
1815 continue;
1816
1817 if (!tmpbuf) {
1818 tmpbuf = kmalloc(bufsize, GFP_KERNEL);
1819 if (!tmpbuf)
1820 return -ENOMEM;
1821 }
1822
1823 tmp = kstrdup(argv[i], GFP_KERNEL);
1824 if (!tmp)
1825 return -ENOMEM;
1826
1827 equal = strchr(tmp, '=');
1828 if (equal)
1829 *equal = '\0';
1830 arg_len = strlen(argv[i]);
1831 tmp[arg_len - 4] = '\0';
1832 if (argv[i][arg_len - 1] == 'd')
1833 ret = snprintf(tmpbuf + used, bufsize - used,
1834 "%s%s+0x0(+0x%zx(%s)):string",
1835 equal ? tmp : "", equal ? "=" : "",
1836 offsetof(struct dentry, d_name.name),
1837 equal ? equal + 1 : tmp);
1838 else
1839 ret = snprintf(tmpbuf + used, bufsize - used,
1840 "%s%s+0x0(+0x%zx(+0x%zx(%s))):string",
1841 equal ? tmp : "", equal ? "=" : "",
1842 offsetof(struct dentry, d_name.name),
1843 offsetof(struct file, f_path.dentry),
1844 equal ? equal + 1 : tmp);
1845
1846 if (ret >= bufsize - used)
1847 return -ENOMEM;
1848 argv[i] = tmpbuf + used;
1849 used += ret + 1;
1850 }
1851
1852 *buf = no_free_ptr(tmpbuf);
1853 return 0;
1854 }
1855
traceprobe_finish_parse(struct traceprobe_parse_context * ctx)1856 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1857 {
1858 clear_btf_context(ctx);
1859 }
1860
traceprobe_update_arg(struct probe_arg * arg)1861 int traceprobe_update_arg(struct probe_arg *arg)
1862 {
1863 struct fetch_insn *code = arg->code;
1864 long offset;
1865 char *tmp;
1866 char c;
1867 int ret = 0;
1868
1869 while (code && code->op != FETCH_OP_END) {
1870 if (code->op == FETCH_NOP_SYMBOL) {
1871 if (code[1].op != FETCH_OP_IMM)
1872 return -EINVAL;
1873
1874 tmp = strpbrk(code->data, "+-");
1875 if (tmp)
1876 c = *tmp;
1877 ret = traceprobe_split_symbol_offset(code->data,
1878 &offset);
1879 if (ret)
1880 return ret;
1881
1882 code[1].immediate =
1883 (unsigned long)kallsyms_lookup_name(code->data);
1884 if (tmp)
1885 *tmp = c;
1886 if (!code[1].immediate)
1887 return -ENOENT;
1888 code[1].immediate += offset;
1889 }
1890 code++;
1891 }
1892 return 0;
1893 }
1894
1895 /* When len=0, we just calculate the needed length */
1896 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)1897 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1898 enum probe_print_type ptype)
1899 {
1900 struct probe_arg *parg;
1901 int i, j;
1902 int pos = 0;
1903 const char *fmt, *arg;
1904
1905 switch (ptype) {
1906 case PROBE_PRINT_NORMAL:
1907 fmt = "(%lx)";
1908 arg = ", REC->" FIELD_STRING_IP;
1909 break;
1910 case PROBE_PRINT_RETURN:
1911 fmt = "(%lx <- %lx)";
1912 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1913 break;
1914 case PROBE_PRINT_EVENT:
1915 fmt = "";
1916 arg = "";
1917 break;
1918 default:
1919 WARN_ON_ONCE(1);
1920 return 0;
1921 }
1922
1923 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1924
1925 for (i = 0; i < tp->nr_args; i++) {
1926 parg = tp->args + i;
1927 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1928 if (parg->count) {
1929 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1930 parg->type->fmt);
1931 for (j = 1; j < parg->count; j++)
1932 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1933 parg->type->fmt);
1934 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1935 } else
1936 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1937 parg->type->fmt);
1938 }
1939
1940 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1941
1942 for (i = 0; i < tp->nr_args; i++) {
1943 parg = tp->args + i;
1944 if (parg->count) {
1945 if (parg->type->is_string)
1946 fmt = ", __get_str(%s[%d])";
1947 else
1948 fmt = ", REC->%s[%d]";
1949 for (j = 0; j < parg->count; j++)
1950 pos += snprintf(buf + pos, LEN_OR_ZERO,
1951 fmt, parg->name, j);
1952 } else {
1953 if (parg->type->is_string)
1954 fmt = ", __get_str(%s)";
1955 else
1956 fmt = ", REC->%s";
1957 pos += snprintf(buf + pos, LEN_OR_ZERO,
1958 fmt, parg->name);
1959 }
1960 }
1961
1962 /* return the length of print_fmt */
1963 return pos;
1964 }
1965 #undef LEN_OR_ZERO
1966
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)1967 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1968 {
1969 struct trace_event_call *call = trace_probe_event_call(tp);
1970 int len;
1971 char *print_fmt;
1972
1973 /* First: called with 0 length to calculate the needed length */
1974 len = __set_print_fmt(tp, NULL, 0, ptype);
1975 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1976 if (!print_fmt)
1977 return -ENOMEM;
1978
1979 /* Second: actually write the @print_fmt */
1980 __set_print_fmt(tp, print_fmt, len + 1, ptype);
1981 call->print_fmt = print_fmt;
1982
1983 return 0;
1984 }
1985
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)1986 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1987 size_t offset, struct trace_probe *tp)
1988 {
1989 int ret, i;
1990
1991 /* Set argument names as fields */
1992 for (i = 0; i < tp->nr_args; i++) {
1993 struct probe_arg *parg = &tp->args[i];
1994 const char *fmt = parg->type->fmttype;
1995 int size = parg->type->size;
1996
1997 if (parg->fmt)
1998 fmt = parg->fmt;
1999 if (parg->count)
2000 size *= parg->count;
2001 ret = trace_define_field(event_call, fmt, parg->name,
2002 offset + parg->offset, size,
2003 parg->type->is_signed,
2004 FILTER_OTHER);
2005 if (ret)
2006 return ret;
2007 }
2008 return 0;
2009 }
2010
trace_probe_event_free(struct trace_probe_event * tpe)2011 static void trace_probe_event_free(struct trace_probe_event *tpe)
2012 {
2013 kfree(tpe->class.system);
2014 kfree(tpe->call.name);
2015 kfree(tpe->call.print_fmt);
2016 kfree(tpe);
2017 }
2018
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)2019 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
2020 {
2021 if (trace_probe_has_sibling(tp))
2022 return -EBUSY;
2023
2024 list_del_init(&tp->list);
2025 trace_probe_event_free(tp->event);
2026
2027 tp->event = to->event;
2028 list_add_tail(&tp->list, trace_probe_probe_list(to));
2029
2030 return 0;
2031 }
2032
trace_probe_unlink(struct trace_probe * tp)2033 void trace_probe_unlink(struct trace_probe *tp)
2034 {
2035 list_del_init(&tp->list);
2036 if (list_empty(trace_probe_probe_list(tp)))
2037 trace_probe_event_free(tp->event);
2038 tp->event = NULL;
2039 }
2040
trace_probe_cleanup(struct trace_probe * tp)2041 void trace_probe_cleanup(struct trace_probe *tp)
2042 {
2043 int i;
2044
2045 for (i = 0; i < tp->nr_args; i++)
2046 traceprobe_free_probe_arg(&tp->args[i]);
2047
2048 if (tp->entry_arg) {
2049 kfree(tp->entry_arg->code);
2050 kfree(tp->entry_arg);
2051 tp->entry_arg = NULL;
2052 }
2053
2054 if (tp->event)
2055 trace_probe_unlink(tp);
2056 }
2057
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter,int nargs)2058 int trace_probe_init(struct trace_probe *tp, const char *event,
2059 const char *group, bool alloc_filter, int nargs)
2060 {
2061 struct trace_event_call *call;
2062 size_t size = sizeof(struct trace_probe_event);
2063 int ret = 0;
2064
2065 if (!event || !group)
2066 return -EINVAL;
2067
2068 if (alloc_filter)
2069 size += sizeof(struct trace_uprobe_filter);
2070
2071 tp->event = kzalloc(size, GFP_KERNEL);
2072 if (!tp->event)
2073 return -ENOMEM;
2074
2075 INIT_LIST_HEAD(&tp->event->files);
2076 INIT_LIST_HEAD(&tp->event->class.fields);
2077 INIT_LIST_HEAD(&tp->event->probes);
2078 INIT_LIST_HEAD(&tp->list);
2079 list_add(&tp->list, &tp->event->probes);
2080
2081 call = trace_probe_event_call(tp);
2082 call->class = &tp->event->class;
2083 call->name = kstrdup(event, GFP_KERNEL);
2084 if (!call->name) {
2085 ret = -ENOMEM;
2086 goto error;
2087 }
2088
2089 tp->event->class.system = kstrdup(group, GFP_KERNEL);
2090 if (!tp->event->class.system) {
2091 ret = -ENOMEM;
2092 goto error;
2093 }
2094
2095 tp->nr_args = nargs;
2096 /* Make sure pointers in args[] are NULL */
2097 if (nargs)
2098 memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
2099
2100 return 0;
2101
2102 error:
2103 trace_probe_cleanup(tp);
2104 return ret;
2105 }
2106
2107 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)2108 find_trace_event_call(const char *system, const char *event_name)
2109 {
2110 struct trace_event_call *tp_event;
2111 const char *name;
2112
2113 list_for_each_entry(tp_event, &ftrace_events, list) {
2114 if (!tp_event->class->system ||
2115 strcmp(system, tp_event->class->system))
2116 continue;
2117 name = trace_event_name(tp_event);
2118 if (!name || strcmp(event_name, name))
2119 continue;
2120 return tp_event;
2121 }
2122
2123 return NULL;
2124 }
2125
trace_probe_register_event_call(struct trace_probe * tp)2126 int trace_probe_register_event_call(struct trace_probe *tp)
2127 {
2128 struct trace_event_call *call = trace_probe_event_call(tp);
2129 int ret;
2130
2131 lockdep_assert_held(&event_mutex);
2132
2133 if (find_trace_event_call(trace_probe_group_name(tp),
2134 trace_probe_name(tp)))
2135 return -EEXIST;
2136
2137 ret = register_trace_event(&call->event);
2138 if (!ret)
2139 return -ENODEV;
2140
2141 ret = trace_add_event_call(call);
2142 if (ret)
2143 unregister_trace_event(&call->event);
2144
2145 return ret;
2146 }
2147
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)2148 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2149 {
2150 struct event_file_link *link;
2151
2152 link = kmalloc(sizeof(*link), GFP_KERNEL);
2153 if (!link)
2154 return -ENOMEM;
2155
2156 link->file = file;
2157 INIT_LIST_HEAD(&link->list);
2158 list_add_tail_rcu(&link->list, &tp->event->files);
2159 trace_probe_set_flag(tp, TP_FLAG_TRACE);
2160 return 0;
2161 }
2162
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)2163 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2164 struct trace_event_file *file)
2165 {
2166 struct event_file_link *link;
2167
2168 trace_probe_for_each_link(link, tp) {
2169 if (link->file == file)
2170 return link;
2171 }
2172
2173 return NULL;
2174 }
2175
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)2176 int trace_probe_remove_file(struct trace_probe *tp,
2177 struct trace_event_file *file)
2178 {
2179 struct event_file_link *link;
2180
2181 link = trace_probe_get_file_link(tp, file);
2182 if (!link)
2183 return -ENOENT;
2184
2185 list_del_rcu(&link->list);
2186 kvfree_rcu_mightsleep(link);
2187
2188 if (list_empty(&tp->event->files))
2189 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2190
2191 return 0;
2192 }
2193
2194 /*
2195 * Return the smallest index of different type argument (start from 1).
2196 * If all argument types and name are same, return 0.
2197 */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)2198 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2199 {
2200 int i;
2201
2202 /* In case of more arguments */
2203 if (a->nr_args < b->nr_args)
2204 return a->nr_args + 1;
2205 if (a->nr_args > b->nr_args)
2206 return b->nr_args + 1;
2207
2208 for (i = 0; i < a->nr_args; i++) {
2209 if ((b->nr_args <= i) ||
2210 ((a->args[i].type != b->args[i].type) ||
2211 (a->args[i].count != b->args[i].count) ||
2212 strcmp(a->args[i].name, b->args[i].name)))
2213 return i + 1;
2214 }
2215
2216 return 0;
2217 }
2218
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)2219 bool trace_probe_match_command_args(struct trace_probe *tp,
2220 int argc, const char **argv)
2221 {
2222 char buf[MAX_ARGSTR_LEN + 1];
2223 int i;
2224
2225 if (tp->nr_args < argc)
2226 return false;
2227
2228 for (i = 0; i < argc; i++) {
2229 snprintf(buf, sizeof(buf), "%s=%s",
2230 tp->args[i].name, tp->args[i].comm);
2231 if (strcmp(buf, argv[i]))
2232 return false;
2233 }
2234 return true;
2235 }
2236
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))2237 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2238 {
2239 int argc = 0, ret = 0;
2240 char **argv;
2241
2242 argv = argv_split(GFP_KERNEL, raw_command, &argc);
2243 if (!argv)
2244 return -ENOMEM;
2245
2246 if (argc)
2247 ret = createfn(argc, (const char **)argv);
2248
2249 argv_free(argv);
2250
2251 return ret;
2252 }
2253
trace_probe_print_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)2254 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2255 u8 *data, void *field)
2256 {
2257 void *p;
2258 int i, j;
2259
2260 for (i = 0; i < nr_args; i++) {
2261 struct probe_arg *a = args + i;
2262
2263 trace_seq_printf(s, " %s=", a->name);
2264 if (likely(!a->count)) {
2265 if (!a->type->print(s, data + a->offset, field))
2266 return -ENOMEM;
2267 continue;
2268 }
2269 trace_seq_putc(s, '{');
2270 p = data + a->offset;
2271 for (j = 0; j < a->count; j++) {
2272 if (!a->type->print(s, p, field))
2273 return -ENOMEM;
2274 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2275 p += a->type->size;
2276 }
2277 }
2278 return 0;
2279 }
2280