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 separator 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_obj(*tp->entry_arg);
842 if (!earg)
843 return -ENOMEM;
844 earg->size = 2 * tp->nr_args + 1;
845 earg->code = kzalloc_objs(struct fetch_insn, earg->size);
846 if (!earg->code) {
847 kfree(earg);
848 return -ENOMEM;
849 }
850 /* Fill the code buffer with 'end' to simplify it */
851 for (i = 0; i < earg->size; i++)
852 earg->code[i].op = FETCH_OP_END;
853 tp->entry_arg = earg;
854 store_entry_arg_at(earg->code, argnum, 0);
855 return 0;
856 }
857
858 /*
859 * NOTE: if anyone change the following rule, please rewrite this.
860 * The entry code array is filled with the pair of
861 *
862 * [FETCH_OP_ARG(argnum)]
863 * [FETCH_OP_ST_EDATA(offset of entry data buffer)]
864 *
865 * and the rest of entries are filled with [FETCH_OP_END].
866 * The offset should be incremented, thus the last pair should
867 * have the largest offset.
868 */
869
870 /* Search the offset for the sprcified argnum. */
871 for (i = 0; i < earg->size - 1 && earg->code[i].op != FETCH_OP_END; i += 2) {
872 if (WARN_ON_ONCE(earg->code[i].op != FETCH_OP_ARG))
873 return -EINVAL;
874
875 if (earg->code[i].param != argnum)
876 continue;
877
878 if (WARN_ON_ONCE(earg->code[i + 1].op != FETCH_OP_ST_EDATA))
879 return -EINVAL;
880
881 return earg->code[i + 1].offset;
882 }
883 /* Not found, append new entry if possible. */
884 if (i >= earg->size - 1)
885 return -ENOSPC;
886
887 /* The last entry must have the largest offset. */
888 if (i != 0) {
889 if (WARN_ON_ONCE(earg->code[i - 1].op != FETCH_OP_ST_EDATA))
890 return -EINVAL;
891 last_offset = earg->code[i - 1].offset;
892 }
893
894 offset = last_offset + sizeof(unsigned long);
895 store_entry_arg_at(&earg->code[i], argnum, offset);
896 return offset;
897 }
898
traceprobe_get_entry_data_size(struct trace_probe * tp)899 int traceprobe_get_entry_data_size(struct trace_probe *tp)
900 {
901 struct probe_entry_arg *earg = tp->entry_arg;
902
903 if (!earg)
904 return 0;
905
906 return get_entry_arg_max_offset(earg) + sizeof(unsigned long);
907 }
908
store_trace_entry_data(void * edata,struct trace_probe * tp,struct pt_regs * regs)909 void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
910 {
911 struct probe_entry_arg *earg = tp->entry_arg;
912 unsigned long val = 0;
913 int i;
914
915 if (!earg)
916 return;
917
918 for (i = 0; i < earg->size; i++) {
919 struct fetch_insn *code = &earg->code[i];
920
921 switch (code->op) {
922 case FETCH_OP_ARG:
923 val = regs_get_kernel_argument(regs, code->param);
924 break;
925 case FETCH_OP_ST_EDATA:
926 *(unsigned long *)((unsigned long)edata + code->offset) = val;
927 break;
928 case FETCH_OP_END:
929 goto end;
930 default:
931 break;
932 }
933 }
934 end:
935 return;
936 }
NOKPROBE_SYMBOL(store_trace_entry_data)937 NOKPROBE_SYMBOL(store_trace_entry_data)
938 #endif
939
940 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
941
942 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
943 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
944 struct fetch_insn **pcode,
945 struct fetch_insn *end,
946 struct traceprobe_parse_context *ctx)
947 {
948 struct fetch_insn *code = *pcode;
949 int err = TP_ERR_BAD_VAR;
950 char *arg = orig_arg + 1;
951 unsigned long param;
952 int ret = 0;
953 int len;
954
955 if (ctx->flags & TPARG_FL_TEVENT) {
956 if (code->data)
957 return -EFAULT;
958 ret = parse_trace_event_arg(arg, code, ctx);
959 if (!ret)
960 return 0;
961 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
962 code->op = FETCH_OP_COMM;
963 return 0;
964 }
965 /* backward compatibility */
966 ctx->offset = 0;
967 goto inval;
968 }
969
970 if (str_has_prefix(arg, "retval")) {
971 if (!(ctx->flags & TPARG_FL_RETURN)) {
972 err = TP_ERR_RETVAL_ON_PROBE;
973 goto inval;
974 }
975 if (!(ctx->flags & TPARG_FL_KERNEL) ||
976 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
977 code->op = FETCH_OP_RETVAL;
978 return 0;
979 }
980 return parse_btf_arg(orig_arg, pcode, end, ctx);
981 }
982
983 len = str_has_prefix(arg, "stack");
984 if (len) {
985
986 if (arg[len] == '\0') {
987 code->op = FETCH_OP_STACKP;
988 return 0;
989 }
990
991 if (isdigit(arg[len])) {
992 ret = kstrtoul(arg + len, 10, ¶m);
993 if (ret)
994 goto inval;
995
996 if ((ctx->flags & TPARG_FL_KERNEL) &&
997 param > PARAM_MAX_STACK) {
998 err = TP_ERR_BAD_STACK_NUM;
999 goto inval;
1000 }
1001 code->op = FETCH_OP_STACK;
1002 code->param = (unsigned int)param;
1003 return 0;
1004 }
1005 goto inval;
1006 }
1007
1008 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
1009 code->op = FETCH_OP_COMM;
1010 return 0;
1011 }
1012
1013 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1014 len = str_has_prefix(arg, "arg");
1015 if (len) {
1016 ret = kstrtoul(arg + len, 10, ¶m);
1017 if (ret)
1018 goto inval;
1019
1020 if (!param || param > PARAM_MAX_STACK) {
1021 err = TP_ERR_BAD_ARG_NUM;
1022 goto inval;
1023 }
1024 param--; /* argN starts from 1, but internal arg[N] starts from 0 */
1025
1026 if (tparg_is_function_entry(ctx->flags)) {
1027 code->op = FETCH_OP_ARG;
1028 code->param = (unsigned int)param;
1029 /*
1030 * The tracepoint probe will probe a stub function, and the
1031 * first parameter of the stub is a dummy and should be ignored.
1032 */
1033 if (ctx->flags & TPARG_FL_TPOINT)
1034 code->param++;
1035 } else if (tparg_is_function_return(ctx->flags)) {
1036 /* function entry argument access from return probe */
1037 ret = __store_entry_arg(ctx->tp, param);
1038 if (ret < 0) /* This error should be an internal error */
1039 return ret;
1040
1041 code->op = FETCH_OP_EDATA;
1042 code->offset = ret;
1043 } else {
1044 err = TP_ERR_NOFENTRY_ARGS;
1045 goto inval;
1046 }
1047 return 0;
1048 }
1049 #endif
1050
1051 inval:
1052 __trace_probe_log_err(ctx->offset, err);
1053 return -EINVAL;
1054 }
1055
str_to_immediate(char * str,unsigned long * imm)1056 static int str_to_immediate(char *str, unsigned long *imm)
1057 {
1058 if (isdigit(str[0]))
1059 return kstrtoul(str, 0, imm);
1060 else if (str[0] == '-')
1061 return kstrtol(str, 0, (long *)imm);
1062 else if (str[0] == '+')
1063 return kstrtol(str + 1, 0, (long *)imm);
1064 return -EINVAL;
1065 }
1066
__parse_imm_string(char * str,char ** pbuf,int offs)1067 static int __parse_imm_string(char *str, char **pbuf, int offs)
1068 {
1069 size_t len = strlen(str);
1070
1071 if (str[len - 1] != '"') {
1072 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1073 return -EINVAL;
1074 }
1075 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1076 if (!*pbuf)
1077 return -ENOMEM;
1078 return 0;
1079 }
1080
1081 /* Recursive argument parser */
1082 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)1083 parse_probe_arg(char *arg, const struct fetch_type *type,
1084 struct fetch_insn **pcode, struct fetch_insn *end,
1085 struct traceprobe_parse_context *ctx)
1086 {
1087 struct fetch_insn *code = *pcode;
1088 unsigned long param;
1089 int deref = FETCH_OP_DEREF;
1090 long offset = 0;
1091 char *tmp;
1092 int ret = 0;
1093
1094 switch (arg[0]) {
1095 case '$':
1096 ret = parse_probe_vars(arg, type, pcode, end, ctx);
1097 break;
1098
1099 case '%': /* named register */
1100 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1101 /* eprobe and fprobe do not handle registers */
1102 trace_probe_log_err(ctx->offset, BAD_VAR);
1103 break;
1104 }
1105 ret = regs_query_register_offset(arg + 1);
1106 if (ret >= 0) {
1107 code->op = FETCH_OP_REG;
1108 code->param = (unsigned int)ret;
1109 ret = 0;
1110 } else
1111 trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1112 break;
1113
1114 case '@': /* memory, file-offset or symbol */
1115 if (isdigit(arg[1])) {
1116 ret = kstrtoul(arg + 1, 0, ¶m);
1117 if (ret) {
1118 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1119 break;
1120 }
1121 /* load address */
1122 code->op = FETCH_OP_IMM;
1123 code->immediate = param;
1124 } else if (arg[1] == '+') {
1125 /* kprobes don't support file offsets */
1126 if (ctx->flags & TPARG_FL_KERNEL) {
1127 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1128 return -EINVAL;
1129 }
1130 ret = kstrtol(arg + 2, 0, &offset);
1131 if (ret) {
1132 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1133 break;
1134 }
1135
1136 code->op = FETCH_OP_FOFFS;
1137 code->immediate = (unsigned long)offset; // imm64?
1138 } else {
1139 /* uprobes don't support symbols */
1140 if (!(ctx->flags & TPARG_FL_KERNEL)) {
1141 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1142 return -EINVAL;
1143 }
1144 /* Preserve symbol for updating */
1145 code->op = FETCH_NOP_SYMBOL;
1146 code->data = kstrdup(arg + 1, GFP_KERNEL);
1147 if (!code->data)
1148 return -ENOMEM;
1149 if (++code == end) {
1150 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1151 return -EINVAL;
1152 }
1153 code->op = FETCH_OP_IMM;
1154 code->immediate = 0;
1155 }
1156 /* These are fetching from memory */
1157 if (++code == end) {
1158 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1159 return -EINVAL;
1160 }
1161 *pcode = code;
1162 code->op = FETCH_OP_DEREF;
1163 code->offset = offset;
1164 break;
1165
1166 case '+': /* deref memory */
1167 case '-':
1168 if (arg[1] == 'u') {
1169 deref = FETCH_OP_UDEREF;
1170 arg[1] = arg[0];
1171 arg++;
1172 }
1173 if (arg[0] == '+')
1174 arg++; /* Skip '+', because kstrtol() rejects it. */
1175 tmp = strchr(arg, '(');
1176 if (!tmp) {
1177 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1178 return -EINVAL;
1179 }
1180 *tmp = '\0';
1181 ret = kstrtol(arg, 0, &offset);
1182 if (ret) {
1183 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1184 break;
1185 }
1186 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1187 arg = tmp + 1;
1188 tmp = strrchr(arg, ')');
1189 if (!tmp) {
1190 trace_probe_log_err(ctx->offset + strlen(arg),
1191 DEREF_OPEN_BRACE);
1192 return -EINVAL;
1193 } else {
1194 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1195 int cur_offs = ctx->offset;
1196
1197 *tmp = '\0';
1198 ret = parse_probe_arg(arg, t2, &code, end, ctx);
1199 if (ret)
1200 break;
1201 ctx->offset = cur_offs;
1202 if (code->op == FETCH_OP_COMM ||
1203 code->op == FETCH_OP_DATA) {
1204 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1205 return -EINVAL;
1206 }
1207 if (++code == end) {
1208 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1209 return -EINVAL;
1210 }
1211 *pcode = code;
1212
1213 code->op = deref;
1214 code->offset = offset;
1215 /* Reset the last type if used */
1216 ctx->last_type = NULL;
1217 }
1218 break;
1219 case '\\': /* Immediate value */
1220 if (arg[1] == '"') { /* Immediate string */
1221 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1222 if (ret)
1223 break;
1224 code->op = FETCH_OP_DATA;
1225 code->data = tmp;
1226 } else {
1227 ret = str_to_immediate(arg + 1, &code->immediate);
1228 if (ret)
1229 trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1230 else
1231 code->op = FETCH_OP_IMM;
1232 }
1233 break;
1234 default:
1235 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
1236 if (!tparg_is_function_entry(ctx->flags) &&
1237 !tparg_is_function_return(ctx->flags)) {
1238 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1239 return -EINVAL;
1240 }
1241 ret = parse_btf_arg(arg, pcode, end, ctx);
1242 break;
1243 }
1244 }
1245 if (!ret && code->op == FETCH_OP_NOP) {
1246 /* Parsed, but do not find fetch method */
1247 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1248 ret = -EINVAL;
1249 }
1250 return ret;
1251 }
1252
1253 /* 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)1254 static int __parse_bitfield_probe_arg(const char *bf,
1255 const struct fetch_type *t,
1256 struct fetch_insn **pcode)
1257 {
1258 struct fetch_insn *code = *pcode;
1259 unsigned long bw, bo;
1260 char *tail;
1261
1262 if (*bf != 'b')
1263 return 0;
1264
1265 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
1266
1267 if (bw == 0 || *tail != '@')
1268 return -EINVAL;
1269
1270 bf = tail + 1;
1271 bo = simple_strtoul(bf, &tail, 0);
1272
1273 if (tail == bf || *tail != '/')
1274 return -EINVAL;
1275 code++;
1276 if (code->op != FETCH_OP_NOP)
1277 return -EINVAL;
1278 *pcode = code;
1279
1280 code->op = FETCH_OP_MOD_BF;
1281 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1282 code->rshift = BYTES_TO_BITS(t->size) - bw;
1283 code->basesize = t->size;
1284
1285 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1286 }
1287
1288 /* Split type part from @arg and return it. */
parse_probe_arg_type(char * arg,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1289 static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
1290 struct traceprobe_parse_context *ctx)
1291 {
1292 char *t = NULL, *t2, *t3;
1293 int offs;
1294
1295 t = strchr(arg, ':');
1296 if (t) {
1297 *t++ = '\0';
1298 t2 = strchr(t, '[');
1299 if (t2) {
1300 *t2++ = '\0';
1301 t3 = strchr(t2, ']');
1302 if (!t3) {
1303 offs = t2 + strlen(t2) - arg;
1304
1305 trace_probe_log_err(ctx->offset + offs,
1306 ARRAY_NO_CLOSE);
1307 return ERR_PTR(-EINVAL);
1308 } else if (t3[1] != '\0') {
1309 trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1310 BAD_ARRAY_SUFFIX);
1311 return ERR_PTR(-EINVAL);
1312 }
1313 *t3 = '\0';
1314 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1315 trace_probe_log_err(ctx->offset + t2 - arg,
1316 BAD_ARRAY_NUM);
1317 return ERR_PTR(-EINVAL);
1318 }
1319 if (parg->count > MAX_ARRAY_LEN) {
1320 trace_probe_log_err(ctx->offset + t2 - arg,
1321 ARRAY_TOO_BIG);
1322 return ERR_PTR(-EINVAL);
1323 }
1324 }
1325 }
1326 offs = t ? t - arg : 0;
1327
1328 /*
1329 * Since $comm and immediate string can not be dereferenced,
1330 * we can find those by strcmp. But ignore for eprobes.
1331 */
1332 if (!(ctx->flags & TPARG_FL_TEVENT) &&
1333 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1334 strncmp(arg, "\\\"", 2) == 0)) {
1335 /* The type of $comm must be "string", and not an array type. */
1336 if (parg->count || (t && strcmp(t, "string"))) {
1337 trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
1338 return ERR_PTR(-EINVAL);
1339 }
1340 parg->type = find_fetch_type("string", ctx->flags);
1341 } else
1342 parg->type = find_fetch_type(t, ctx->flags);
1343
1344 if (!parg->type) {
1345 trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
1346 return ERR_PTR(-EINVAL);
1347 }
1348
1349 return t;
1350 }
1351
1352 /* 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)1353 static int finalize_fetch_insn(struct fetch_insn *code,
1354 struct probe_arg *parg,
1355 char *type,
1356 int type_offset,
1357 struct traceprobe_parse_context *ctx)
1358 {
1359 struct fetch_insn *scode;
1360 int ret;
1361
1362 /* Store operation */
1363 if (parg->type->is_string) {
1364 /* Check bad combination of the type and the last fetch_insn. */
1365 if (!strcmp(parg->type->name, "symstr")) {
1366 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1367 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1368 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1369 trace_probe_log_err(ctx->offset + type_offset,
1370 BAD_SYMSTRING);
1371 return -EINVAL;
1372 }
1373 } else {
1374 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1375 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1376 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1377 trace_probe_log_err(ctx->offset + type_offset,
1378 BAD_STRING);
1379 return -EINVAL;
1380 }
1381 }
1382
1383 if (!strcmp(parg->type->name, "symstr") ||
1384 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1385 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1386 parg->count) {
1387 /*
1388 * IMM, DATA and COMM is pointing actual address, those
1389 * must be kept, and if parg->count != 0, this is an
1390 * array of string pointers instead of string address
1391 * itself.
1392 * For the symstr, it doesn't need to dereference, thus
1393 * it just get the value.
1394 */
1395 code++;
1396 if (code->op != FETCH_OP_NOP) {
1397 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1398 return -EINVAL;
1399 }
1400 }
1401
1402 /* If op == DEREF, replace it with STRING */
1403 if (!strcmp(parg->type->name, "ustring") ||
1404 code->op == FETCH_OP_UDEREF)
1405 code->op = FETCH_OP_ST_USTRING;
1406 else if (!strcmp(parg->type->name, "symstr"))
1407 code->op = FETCH_OP_ST_SYMSTR;
1408 else
1409 code->op = FETCH_OP_ST_STRING;
1410 code->size = parg->type->size;
1411 parg->dynamic = true;
1412 } else if (code->op == FETCH_OP_DEREF) {
1413 code->op = FETCH_OP_ST_MEM;
1414 code->size = parg->type->size;
1415 } else if (code->op == FETCH_OP_UDEREF) {
1416 code->op = FETCH_OP_ST_UMEM;
1417 code->size = parg->type->size;
1418 } else {
1419 code++;
1420 if (code->op != FETCH_OP_NOP) {
1421 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1422 return -E2BIG;
1423 }
1424 code->op = FETCH_OP_ST_RAW;
1425 code->size = parg->type->size;
1426 }
1427
1428 /* Save storing fetch_insn. */
1429 scode = code;
1430
1431 /* Modify operation */
1432 if (type != NULL) {
1433 /* Bitfield needs a special fetch_insn. */
1434 ret = __parse_bitfield_probe_arg(type, parg->type, &code);
1435 if (ret) {
1436 trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
1437 return ret;
1438 }
1439 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1440 ctx->last_type) {
1441 /* If user not specified the type, try parsing BTF bitfield. */
1442 ret = parse_btf_bitfield(&code, ctx);
1443 if (ret)
1444 return ret;
1445 }
1446
1447 /* Loop(Array) operation */
1448 if (parg->count) {
1449 if (scode->op != FETCH_OP_ST_MEM &&
1450 scode->op != FETCH_OP_ST_STRING &&
1451 scode->op != FETCH_OP_ST_USTRING) {
1452 trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
1453 return -EINVAL;
1454 }
1455 code++;
1456 if (code->op != FETCH_OP_NOP) {
1457 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1458 return -E2BIG;
1459 }
1460 code->op = FETCH_OP_LP_ARRAY;
1461 code->param = parg->count;
1462 }
1463
1464 /* Finalize the fetch_insn array. */
1465 code++;
1466 code->op = FETCH_OP_END;
1467
1468 return 0;
1469 }
1470
1471 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1472 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1473 struct probe_arg *parg,
1474 struct traceprobe_parse_context *ctx)
1475 {
1476 struct fetch_insn *code, *tmp = NULL;
1477 char *type, *arg __free(kfree) = NULL;
1478 int ret, len;
1479
1480 len = strlen(argv);
1481 if (len > MAX_ARGSTR_LEN) {
1482 trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1483 return -E2BIG;
1484 } else if (len == 0) {
1485 trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1486 return -EINVAL;
1487 }
1488
1489 arg = kstrdup(argv, GFP_KERNEL);
1490 if (!arg)
1491 return -ENOMEM;
1492
1493 parg->comm = kstrdup(arg, GFP_KERNEL);
1494 if (!parg->comm)
1495 return -ENOMEM;
1496
1497 type = parse_probe_arg_type(arg, parg, ctx);
1498 if (IS_ERR(type))
1499 return PTR_ERR(type);
1500
1501 code = tmp = kzalloc_objs(*code, FETCH_INSN_MAX);
1502 if (!code)
1503 return -ENOMEM;
1504 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1505
1506 ctx->last_type = NULL;
1507 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1508 ctx);
1509 if (ret < 0)
1510 goto fail;
1511
1512 /* Update storing type if BTF is available */
1513 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1514 ctx->last_type) {
1515 if (!type) {
1516 parg->type = find_fetch_type_from_btf_type(ctx);
1517 } else if (strstr(type, "string")) {
1518 ret = check_prepare_btf_string_fetch(type, &code, ctx);
1519 if (ret)
1520 goto fail;
1521 }
1522 }
1523 parg->offset = *size;
1524 *size += parg->type->size * (parg->count ?: 1);
1525
1526 if (parg->count) {
1527 len = strlen(parg->type->fmttype) + 6;
1528 parg->fmt = kmalloc(len, GFP_KERNEL);
1529 if (!parg->fmt) {
1530 ret = -ENOMEM;
1531 goto fail;
1532 }
1533 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1534 parg->count);
1535 }
1536
1537 ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
1538 if (ret < 0)
1539 goto fail;
1540
1541 for (; code < tmp + FETCH_INSN_MAX; code++)
1542 if (code->op == FETCH_OP_END)
1543 break;
1544 /* Shrink down the code buffer */
1545 parg->code = kzalloc_objs(*code, code - tmp + 1);
1546 if (!parg->code)
1547 ret = -ENOMEM;
1548 else
1549 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1550
1551 fail:
1552 if (ret < 0) {
1553 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1554 if (code->op == FETCH_NOP_SYMBOL ||
1555 code->op == FETCH_OP_DATA)
1556 kfree(code->data);
1557 }
1558 kfree(tmp);
1559
1560 return ret;
1561 }
1562
1563 /* 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)1564 static int traceprobe_conflict_field_name(const char *name,
1565 struct probe_arg *args, int narg)
1566 {
1567 int i;
1568
1569 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1570 if (strcmp(reserved_field_names[i], name) == 0)
1571 return 1;
1572
1573 for (i = 0; i < narg; i++)
1574 if (strcmp(args[i].name, name) == 0)
1575 return 1;
1576
1577 return 0;
1578 }
1579
generate_probe_arg_name(const char * arg,int idx)1580 static char *generate_probe_arg_name(const char *arg, int idx)
1581 {
1582 char *name = NULL;
1583 const char *end;
1584
1585 /*
1586 * If argument name is omitted, try arg as a name (BTF variable)
1587 * or "argN".
1588 */
1589 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1590 end = strchr(arg, ':');
1591 if (!end)
1592 end = arg + strlen(arg);
1593
1594 name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1595 if (!name || !is_good_name(name)) {
1596 kfree(name);
1597 name = NULL;
1598 }
1599 }
1600
1601 if (!name)
1602 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1603
1604 return name;
1605 }
1606
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,struct traceprobe_parse_context * ctx)1607 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1608 struct traceprobe_parse_context *ctx)
1609 {
1610 struct probe_arg *parg = &tp->args[i];
1611 const char *body;
1612
1613 ctx->tp = tp;
1614 body = strchr(arg, '=');
1615 if (body) {
1616 if (body - arg > MAX_ARG_NAME_LEN) {
1617 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1618 return -EINVAL;
1619 } else if (body == arg) {
1620 trace_probe_log_err(0, NO_ARG_NAME);
1621 return -EINVAL;
1622 }
1623 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1624 body++;
1625 } else {
1626 parg->name = generate_probe_arg_name(arg, i);
1627 body = arg;
1628 }
1629 if (!parg->name)
1630 return -ENOMEM;
1631
1632 if (!is_good_name(parg->name)) {
1633 trace_probe_log_err(0, BAD_ARG_NAME);
1634 return -EINVAL;
1635 }
1636 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1637 trace_probe_log_err(0, USED_ARG_NAME);
1638 return -EINVAL;
1639 }
1640 ctx->offset = body - arg;
1641 /* Parse fetch argument */
1642 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1643 }
1644
traceprobe_free_probe_arg(struct probe_arg * arg)1645 void traceprobe_free_probe_arg(struct probe_arg *arg)
1646 {
1647 struct fetch_insn *code = arg->code;
1648
1649 while (code && code->op != FETCH_OP_END) {
1650 if (code->op == FETCH_NOP_SYMBOL ||
1651 code->op == FETCH_OP_DATA)
1652 kfree(code->data);
1653 code++;
1654 }
1655 kfree(arg->code);
1656 kfree(arg->name);
1657 kfree(arg->comm);
1658 kfree(arg->fmt);
1659 }
1660
argv_has_var_arg(int argc,const char * argv[],int * args_idx,struct traceprobe_parse_context * ctx)1661 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1662 struct traceprobe_parse_context *ctx)
1663 {
1664 int i, found = 0;
1665
1666 for (i = 0; i < argc; i++)
1667 if (str_has_prefix(argv[i], "$arg")) {
1668 trace_probe_log_set_index(i + 2);
1669
1670 if (!tparg_is_function_entry(ctx->flags) &&
1671 !tparg_is_function_return(ctx->flags)) {
1672 trace_probe_log_err(0, NOFENTRY_ARGS);
1673 return -EINVAL;
1674 }
1675
1676 if (isdigit(argv[i][4])) {
1677 found = 1;
1678 continue;
1679 }
1680
1681 if (argv[i][4] != '*') {
1682 trace_probe_log_err(0, BAD_VAR);
1683 return -EINVAL;
1684 }
1685
1686 if (*args_idx >= 0 && *args_idx < argc) {
1687 trace_probe_log_err(0, DOUBLE_ARGS);
1688 return -EINVAL;
1689 }
1690 found = 1;
1691 *args_idx = i;
1692 }
1693
1694 return found;
1695 }
1696
sprint_nth_btf_arg(int idx,const char * type,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1697 static int sprint_nth_btf_arg(int idx, const char *type,
1698 char *buf, int bufsize,
1699 struct traceprobe_parse_context *ctx)
1700 {
1701 const char *name;
1702 int ret;
1703
1704 if (idx >= ctx->nr_params) {
1705 trace_probe_log_err(0, NO_BTFARG);
1706 return -ENOENT;
1707 }
1708 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1709 if (!name) {
1710 trace_probe_log_err(0, NO_BTF_ENTRY);
1711 return -ENOENT;
1712 }
1713 ret = snprintf(buf, bufsize, "%s%s", name, type);
1714 if (ret >= bufsize) {
1715 trace_probe_log_err(0, ARGS_2LONG);
1716 return -E2BIG;
1717 }
1718 return ret;
1719 }
1720
1721 /* 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)1722 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1723 int *new_argc, char *buf, int bufsize,
1724 struct traceprobe_parse_context *ctx)
1725 {
1726 const struct btf_param *params = NULL;
1727 int i, j, n, used, ret, args_idx = -1;
1728 const char **new_argv __free(kfree) = NULL;
1729
1730 ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1731 if (ret < 0)
1732 return ERR_PTR(ret);
1733
1734 if (!ret) {
1735 *new_argc = argc;
1736 return NULL;
1737 }
1738
1739 ret = query_btf_context(ctx);
1740 if (ret < 0 || ctx->nr_params == 0) {
1741 if (args_idx != -1) {
1742 /* $arg* requires BTF info */
1743 trace_probe_log_err(0, NOSUP_BTFARG);
1744 return (const char **)params;
1745 }
1746 *new_argc = argc;
1747 return NULL;
1748 }
1749
1750 if (args_idx >= 0)
1751 *new_argc = argc + ctx->nr_params - 1;
1752 else
1753 *new_argc = argc;
1754
1755 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1756 if (!new_argv)
1757 return ERR_PTR(-ENOMEM);
1758
1759 used = 0;
1760 for (i = 0, j = 0; i < argc; i++) {
1761 trace_probe_log_set_index(i + 2);
1762 if (i == args_idx) {
1763 for (n = 0; n < ctx->nr_params; n++) {
1764 ret = sprint_nth_btf_arg(n, "", buf + used,
1765 bufsize - used, ctx);
1766 if (ret < 0)
1767 return ERR_PTR(ret);
1768
1769 new_argv[j++] = buf + used;
1770 used += ret + 1;
1771 }
1772 continue;
1773 }
1774
1775 if (str_has_prefix(argv[i], "$arg")) {
1776 char *type = NULL;
1777
1778 n = simple_strtoul(argv[i] + 4, &type, 10);
1779 if (type && !(*type == ':' || *type == '\0')) {
1780 trace_probe_log_err(0, BAD_VAR);
1781 return ERR_PTR(-ENOENT);
1782 }
1783 /* Note: $argN starts from $arg1 */
1784 ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1785 bufsize - used, ctx);
1786 if (ret < 0)
1787 return ERR_PTR(ret);
1788 new_argv[j++] = buf + used;
1789 used += ret + 1;
1790 } else
1791 new_argv[j++] = argv[i];
1792 }
1793
1794 return_ptr(new_argv);
1795 }
1796
1797 /* @buf: *buf must be equal to NULL. Caller must to free *buf */
traceprobe_expand_dentry_args(int argc,const char * argv[],char ** buf)1798 int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
1799 {
1800 int i, used, ret;
1801 const int bufsize = MAX_DENTRY_ARGS_LEN;
1802 char *tmpbuf __free(kfree) = NULL;
1803
1804 if (*buf)
1805 return -EINVAL;
1806
1807 used = 0;
1808 for (i = 0; i < argc; i++) {
1809 char *tmp __free(kfree) = NULL;
1810 char *equal;
1811 size_t arg_len;
1812
1813 if (!glob_match("*:%p[dD]", argv[i]))
1814 continue;
1815
1816 if (!tmpbuf) {
1817 tmpbuf = kmalloc(bufsize, GFP_KERNEL);
1818 if (!tmpbuf)
1819 return -ENOMEM;
1820 }
1821
1822 tmp = kstrdup(argv[i], GFP_KERNEL);
1823 if (!tmp)
1824 return -ENOMEM;
1825
1826 equal = strchr(tmp, '=');
1827 if (equal)
1828 *equal = '\0';
1829 arg_len = strlen(argv[i]);
1830 tmp[arg_len - 4] = '\0';
1831 if (argv[i][arg_len - 1] == 'd')
1832 ret = snprintf(tmpbuf + used, bufsize - used,
1833 "%s%s+0x0(+0x%zx(%s)):string",
1834 equal ? tmp : "", equal ? "=" : "",
1835 offsetof(struct dentry, d_name.name),
1836 equal ? equal + 1 : tmp);
1837 else
1838 ret = snprintf(tmpbuf + used, bufsize - used,
1839 "%s%s+0x0(+0x%zx(+0x%zx(%s))):string",
1840 equal ? tmp : "", equal ? "=" : "",
1841 offsetof(struct dentry, d_name.name),
1842 offsetof(struct file, f_path.dentry),
1843 equal ? equal + 1 : tmp);
1844
1845 if (ret >= bufsize - used)
1846 return -ENOMEM;
1847 argv[i] = tmpbuf + used;
1848 used += ret + 1;
1849 }
1850
1851 *buf = no_free_ptr(tmpbuf);
1852 return 0;
1853 }
1854
traceprobe_finish_parse(struct traceprobe_parse_context * ctx)1855 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1856 {
1857 clear_btf_context(ctx);
1858 }
1859
traceprobe_update_arg(struct probe_arg * arg)1860 int traceprobe_update_arg(struct probe_arg *arg)
1861 {
1862 struct fetch_insn *code = arg->code;
1863 long offset;
1864 char *tmp;
1865 char c;
1866 int ret = 0;
1867
1868 while (code && code->op != FETCH_OP_END) {
1869 if (code->op == FETCH_NOP_SYMBOL) {
1870 if (code[1].op != FETCH_OP_IMM)
1871 return -EINVAL;
1872
1873 tmp = strpbrk(code->data, "+-");
1874 if (tmp)
1875 c = *tmp;
1876 ret = traceprobe_split_symbol_offset(code->data,
1877 &offset);
1878 if (ret)
1879 return ret;
1880
1881 code[1].immediate =
1882 (unsigned long)kallsyms_lookup_name(code->data);
1883 if (tmp)
1884 *tmp = c;
1885 if (!code[1].immediate)
1886 return -ENOENT;
1887 code[1].immediate += offset;
1888 }
1889 code++;
1890 }
1891 return 0;
1892 }
1893
1894 /* When len=0, we just calculate the needed length */
1895 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)1896 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1897 enum probe_print_type ptype)
1898 {
1899 struct probe_arg *parg;
1900 int i, j;
1901 int pos = 0;
1902 const char *fmt, *arg;
1903
1904 switch (ptype) {
1905 case PROBE_PRINT_NORMAL:
1906 fmt = "(%lx)";
1907 arg = ", REC->" FIELD_STRING_IP;
1908 break;
1909 case PROBE_PRINT_RETURN:
1910 fmt = "(%lx <- %lx)";
1911 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1912 break;
1913 case PROBE_PRINT_EVENT:
1914 fmt = "";
1915 arg = "";
1916 break;
1917 default:
1918 WARN_ON_ONCE(1);
1919 return 0;
1920 }
1921
1922 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1923
1924 for (i = 0; i < tp->nr_args; i++) {
1925 parg = tp->args + i;
1926 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1927 if (parg->count) {
1928 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1929 parg->type->fmt);
1930 for (j = 1; j < parg->count; j++)
1931 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1932 parg->type->fmt);
1933 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1934 } else
1935 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1936 parg->type->fmt);
1937 }
1938
1939 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1940
1941 for (i = 0; i < tp->nr_args; i++) {
1942 parg = tp->args + i;
1943 if (parg->count) {
1944 if (parg->type->is_string)
1945 fmt = ", __get_str(%s[%d])";
1946 else
1947 fmt = ", REC->%s[%d]";
1948 for (j = 0; j < parg->count; j++)
1949 pos += snprintf(buf + pos, LEN_OR_ZERO,
1950 fmt, parg->name, j);
1951 } else {
1952 if (parg->type->is_string)
1953 fmt = ", __get_str(%s)";
1954 else
1955 fmt = ", REC->%s";
1956 pos += snprintf(buf + pos, LEN_OR_ZERO,
1957 fmt, parg->name);
1958 }
1959 }
1960
1961 /* return the length of print_fmt */
1962 return pos;
1963 }
1964 #undef LEN_OR_ZERO
1965
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)1966 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1967 {
1968 struct trace_event_call *call = trace_probe_event_call(tp);
1969 int len;
1970 char *print_fmt;
1971
1972 /* First: called with 0 length to calculate the needed length */
1973 len = __set_print_fmt(tp, NULL, 0, ptype);
1974 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1975 if (!print_fmt)
1976 return -ENOMEM;
1977
1978 /* Second: actually write the @print_fmt */
1979 __set_print_fmt(tp, print_fmt, len + 1, ptype);
1980 call->print_fmt = print_fmt;
1981
1982 return 0;
1983 }
1984
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)1985 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1986 size_t offset, struct trace_probe *tp)
1987 {
1988 int ret, i;
1989
1990 /* Set argument names as fields */
1991 for (i = 0; i < tp->nr_args; i++) {
1992 struct probe_arg *parg = &tp->args[i];
1993 const char *fmt = parg->type->fmttype;
1994 int size = parg->type->size;
1995
1996 if (parg->fmt)
1997 fmt = parg->fmt;
1998 if (parg->count)
1999 size *= parg->count;
2000 ret = trace_define_field(event_call, fmt, parg->name,
2001 offset + parg->offset, size,
2002 parg->type->is_signed,
2003 FILTER_OTHER);
2004 if (ret)
2005 return ret;
2006 }
2007 return 0;
2008 }
2009
trace_probe_event_free(struct trace_probe_event * tpe)2010 static void trace_probe_event_free(struct trace_probe_event *tpe)
2011 {
2012 kfree(tpe->class.system);
2013 kfree(tpe->call.name);
2014 kfree(tpe->call.print_fmt);
2015 kfree(tpe);
2016 }
2017
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)2018 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
2019 {
2020 if (trace_probe_has_sibling(tp))
2021 return -EBUSY;
2022
2023 list_del_init(&tp->list);
2024 trace_probe_event_free(tp->event);
2025
2026 tp->event = to->event;
2027 list_add_tail(&tp->list, trace_probe_probe_list(to));
2028
2029 return 0;
2030 }
2031
trace_probe_unlink(struct trace_probe * tp)2032 void trace_probe_unlink(struct trace_probe *tp)
2033 {
2034 list_del_init(&tp->list);
2035 if (list_empty(trace_probe_probe_list(tp)))
2036 trace_probe_event_free(tp->event);
2037 tp->event = NULL;
2038 }
2039
trace_probe_cleanup(struct trace_probe * tp)2040 void trace_probe_cleanup(struct trace_probe *tp)
2041 {
2042 int i;
2043
2044 for (i = 0; i < tp->nr_args; i++)
2045 traceprobe_free_probe_arg(&tp->args[i]);
2046
2047 if (tp->entry_arg) {
2048 kfree(tp->entry_arg->code);
2049 kfree(tp->entry_arg);
2050 tp->entry_arg = NULL;
2051 }
2052
2053 if (tp->event)
2054 trace_probe_unlink(tp);
2055 }
2056
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter,int nargs)2057 int trace_probe_init(struct trace_probe *tp, const char *event,
2058 const char *group, bool alloc_filter, int nargs)
2059 {
2060 struct trace_event_call *call;
2061 size_t size = sizeof(struct trace_probe_event);
2062 int ret = 0;
2063
2064 if (!event || !group)
2065 return -EINVAL;
2066
2067 if (alloc_filter)
2068 size += sizeof(struct trace_uprobe_filter);
2069
2070 tp->event = kzalloc(size, GFP_KERNEL);
2071 if (!tp->event)
2072 return -ENOMEM;
2073
2074 INIT_LIST_HEAD(&tp->event->files);
2075 INIT_LIST_HEAD(&tp->event->class.fields);
2076 INIT_LIST_HEAD(&tp->event->probes);
2077 INIT_LIST_HEAD(&tp->list);
2078 list_add(&tp->list, &tp->event->probes);
2079
2080 call = trace_probe_event_call(tp);
2081 call->class = &tp->event->class;
2082 call->name = kstrdup(event, GFP_KERNEL);
2083 if (!call->name) {
2084 ret = -ENOMEM;
2085 goto error;
2086 }
2087
2088 tp->event->class.system = kstrdup(group, GFP_KERNEL);
2089 if (!tp->event->class.system) {
2090 ret = -ENOMEM;
2091 goto error;
2092 }
2093
2094 tp->nr_args = nargs;
2095 /* Make sure pointers in args[] are NULL */
2096 if (nargs)
2097 memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
2098
2099 return 0;
2100
2101 error:
2102 trace_probe_cleanup(tp);
2103 return ret;
2104 }
2105
2106 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)2107 find_trace_event_call(const char *system, const char *event_name)
2108 {
2109 struct trace_event_call *tp_event;
2110 const char *name;
2111
2112 list_for_each_entry(tp_event, &ftrace_events, list) {
2113 if (!tp_event->class->system ||
2114 strcmp(system, tp_event->class->system))
2115 continue;
2116 name = trace_event_name(tp_event);
2117 if (!name || strcmp(event_name, name))
2118 continue;
2119 return tp_event;
2120 }
2121
2122 return NULL;
2123 }
2124
trace_probe_register_event_call(struct trace_probe * tp)2125 int trace_probe_register_event_call(struct trace_probe *tp)
2126 {
2127 struct trace_event_call *call = trace_probe_event_call(tp);
2128 int ret;
2129
2130 lockdep_assert_held(&event_mutex);
2131
2132 if (find_trace_event_call(trace_probe_group_name(tp),
2133 trace_probe_name(tp)))
2134 return -EEXIST;
2135
2136 ret = register_trace_event(&call->event);
2137 if (!ret)
2138 return -ENODEV;
2139
2140 ret = trace_add_event_call(call);
2141 if (ret)
2142 unregister_trace_event(&call->event);
2143
2144 return ret;
2145 }
2146
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)2147 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2148 {
2149 struct event_file_link *link;
2150
2151 link = kmalloc_obj(*link);
2152 if (!link)
2153 return -ENOMEM;
2154
2155 link->file = file;
2156 INIT_LIST_HEAD(&link->list);
2157 list_add_tail_rcu(&link->list, &tp->event->files);
2158 trace_probe_set_flag(tp, TP_FLAG_TRACE);
2159 return 0;
2160 }
2161
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)2162 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2163 struct trace_event_file *file)
2164 {
2165 struct event_file_link *link;
2166
2167 trace_probe_for_each_link(link, tp) {
2168 if (link->file == file)
2169 return link;
2170 }
2171
2172 return NULL;
2173 }
2174
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)2175 int trace_probe_remove_file(struct trace_probe *tp,
2176 struct trace_event_file *file)
2177 {
2178 struct event_file_link *link;
2179
2180 link = trace_probe_get_file_link(tp, file);
2181 if (!link)
2182 return -ENOENT;
2183
2184 list_del_rcu(&link->list);
2185 kvfree_rcu_mightsleep(link);
2186
2187 if (list_empty(&tp->event->files))
2188 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2189
2190 return 0;
2191 }
2192
2193 /*
2194 * Return the smallest index of different type argument (start from 1).
2195 * If all argument types and name are same, return 0.
2196 */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)2197 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2198 {
2199 int i;
2200
2201 /* In case of more arguments */
2202 if (a->nr_args < b->nr_args)
2203 return a->nr_args + 1;
2204 if (a->nr_args > b->nr_args)
2205 return b->nr_args + 1;
2206
2207 for (i = 0; i < a->nr_args; i++) {
2208 if ((b->nr_args <= i) ||
2209 ((a->args[i].type != b->args[i].type) ||
2210 (a->args[i].count != b->args[i].count) ||
2211 strcmp(a->args[i].name, b->args[i].name)))
2212 return i + 1;
2213 }
2214
2215 return 0;
2216 }
2217
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)2218 bool trace_probe_match_command_args(struct trace_probe *tp,
2219 int argc, const char **argv)
2220 {
2221 char buf[MAX_ARGSTR_LEN + 1];
2222 int i;
2223
2224 if (tp->nr_args < argc)
2225 return false;
2226
2227 for (i = 0; i < argc; i++) {
2228 snprintf(buf, sizeof(buf), "%s=%s",
2229 tp->args[i].name, tp->args[i].comm);
2230 if (strcmp(buf, argv[i]))
2231 return false;
2232 }
2233 return true;
2234 }
2235
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))2236 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2237 {
2238 int argc = 0, ret = 0;
2239 char **argv;
2240
2241 argv = argv_split(GFP_KERNEL, raw_command, &argc);
2242 if (!argv)
2243 return -ENOMEM;
2244
2245 if (argc)
2246 ret = createfn(argc, (const char **)argv);
2247
2248 argv_free(argv);
2249
2250 return ret;
2251 }
2252
trace_probe_print_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)2253 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2254 u8 *data, void *field)
2255 {
2256 void *p;
2257 int i, j;
2258
2259 for (i = 0; i < nr_args; i++) {
2260 struct probe_arg *a = args + i;
2261
2262 trace_seq_printf(s, " %s=", a->name);
2263 if (likely(!a->count)) {
2264 if (!a->type->print(s, data + a->offset, field))
2265 return -ENOMEM;
2266 continue;
2267 }
2268 trace_seq_putc(s, '{');
2269 p = data + a->offset;
2270 for (j = 0; j < a->count; j++) {
2271 if (!a->type->print(s, p, field))
2272 return -ENOMEM;
2273 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2274 p += a->type->size;
2275 }
2276 }
2277 return 0;
2278 }
2279