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