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 #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
__store_entry_arg(struct trace_probe * tp,int argnum)773 static int __store_entry_arg(struct trace_probe *tp, int argnum)
774 {
775 struct probe_entry_arg *earg = tp->entry_arg;
776 bool match = false;
777 int i, offset;
778
779 if (!earg) {
780 earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL);
781 if (!earg)
782 return -ENOMEM;
783 earg->size = 2 * tp->nr_args + 1;
784 earg->code = kcalloc(earg->size, sizeof(struct fetch_insn),
785 GFP_KERNEL);
786 if (!earg->code) {
787 kfree(earg);
788 return -ENOMEM;
789 }
790 /* Fill the code buffer with 'end' to simplify it */
791 for (i = 0; i < earg->size; i++)
792 earg->code[i].op = FETCH_OP_END;
793 tp->entry_arg = earg;
794 }
795
796 offset = 0;
797 for (i = 0; i < earg->size - 1; i++) {
798 switch (earg->code[i].op) {
799 case FETCH_OP_END:
800 earg->code[i].op = FETCH_OP_ARG;
801 earg->code[i].param = argnum;
802 earg->code[i + 1].op = FETCH_OP_ST_EDATA;
803 earg->code[i + 1].offset = offset;
804 return offset;
805 case FETCH_OP_ARG:
806 match = (earg->code[i].param == argnum);
807 break;
808 case FETCH_OP_ST_EDATA:
809 offset = earg->code[i].offset;
810 if (match)
811 return offset;
812 offset += sizeof(unsigned long);
813 break;
814 default:
815 break;
816 }
817 }
818 return -ENOSPC;
819 }
820
traceprobe_get_entry_data_size(struct trace_probe * tp)821 int traceprobe_get_entry_data_size(struct trace_probe *tp)
822 {
823 struct probe_entry_arg *earg = tp->entry_arg;
824 int i, size = 0;
825
826 if (!earg)
827 return 0;
828
829 for (i = 0; i < earg->size; i++) {
830 switch (earg->code[i].op) {
831 case FETCH_OP_END:
832 goto out;
833 case FETCH_OP_ST_EDATA:
834 size = earg->code[i].offset + sizeof(unsigned long);
835 break;
836 default:
837 break;
838 }
839 }
840 out:
841 return size;
842 }
843
store_trace_entry_data(void * edata,struct trace_probe * tp,struct pt_regs * regs)844 void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
845 {
846 struct probe_entry_arg *earg = tp->entry_arg;
847 unsigned long val = 0;
848 int i;
849
850 if (!earg)
851 return;
852
853 for (i = 0; i < earg->size; i++) {
854 struct fetch_insn *code = &earg->code[i];
855
856 switch (code->op) {
857 case FETCH_OP_ARG:
858 val = regs_get_kernel_argument(regs, code->param);
859 break;
860 case FETCH_OP_ST_EDATA:
861 *(unsigned long *)((unsigned long)edata + code->offset) = val;
862 break;
863 case FETCH_OP_END:
864 goto end;
865 default:
866 break;
867 }
868 }
869 end:
870 return;
871 }
NOKPROBE_SYMBOL(store_trace_entry_data)872 NOKPROBE_SYMBOL(store_trace_entry_data)
873 #endif
874
875 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
876
877 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
878 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
879 struct fetch_insn **pcode,
880 struct fetch_insn *end,
881 struct traceprobe_parse_context *ctx)
882 {
883 struct fetch_insn *code = *pcode;
884 int err = TP_ERR_BAD_VAR;
885 char *arg = orig_arg + 1;
886 unsigned long param;
887 int ret = 0;
888 int len;
889
890 if (ctx->flags & TPARG_FL_TEVENT) {
891 if (code->data)
892 return -EFAULT;
893 ret = parse_trace_event_arg(arg, code, ctx);
894 if (!ret)
895 return 0;
896 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
897 code->op = FETCH_OP_COMM;
898 return 0;
899 }
900 /* backward compatibility */
901 ctx->offset = 0;
902 goto inval;
903 }
904
905 if (str_has_prefix(arg, "retval")) {
906 if (!(ctx->flags & TPARG_FL_RETURN)) {
907 err = TP_ERR_RETVAL_ON_PROBE;
908 goto inval;
909 }
910 if (!(ctx->flags & TPARG_FL_KERNEL) ||
911 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
912 code->op = FETCH_OP_RETVAL;
913 return 0;
914 }
915 return parse_btf_arg(orig_arg, pcode, end, ctx);
916 }
917
918 len = str_has_prefix(arg, "stack");
919 if (len) {
920
921 if (arg[len] == '\0') {
922 code->op = FETCH_OP_STACKP;
923 return 0;
924 }
925
926 if (isdigit(arg[len])) {
927 ret = kstrtoul(arg + len, 10, ¶m);
928 if (ret)
929 goto inval;
930
931 if ((ctx->flags & TPARG_FL_KERNEL) &&
932 param > PARAM_MAX_STACK) {
933 err = TP_ERR_BAD_STACK_NUM;
934 goto inval;
935 }
936 code->op = FETCH_OP_STACK;
937 code->param = (unsigned int)param;
938 return 0;
939 }
940 goto inval;
941 }
942
943 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
944 code->op = FETCH_OP_COMM;
945 return 0;
946 }
947
948 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
949 len = str_has_prefix(arg, "arg");
950 if (len) {
951 ret = kstrtoul(arg + len, 10, ¶m);
952 if (ret)
953 goto inval;
954
955 if (!param || param > PARAM_MAX_STACK) {
956 err = TP_ERR_BAD_ARG_NUM;
957 goto inval;
958 }
959 param--; /* argN starts from 1, but internal arg[N] starts from 0 */
960
961 if (tparg_is_function_entry(ctx->flags)) {
962 code->op = FETCH_OP_ARG;
963 code->param = (unsigned int)param;
964 /*
965 * The tracepoint probe will probe a stub function, and the
966 * first parameter of the stub is a dummy and should be ignored.
967 */
968 if (ctx->flags & TPARG_FL_TPOINT)
969 code->param++;
970 } else if (tparg_is_function_return(ctx->flags)) {
971 /* function entry argument access from return probe */
972 ret = __store_entry_arg(ctx->tp, param);
973 if (ret < 0) /* This error should be an internal error */
974 return ret;
975
976 code->op = FETCH_OP_EDATA;
977 code->offset = ret;
978 } else {
979 err = TP_ERR_NOFENTRY_ARGS;
980 goto inval;
981 }
982 return 0;
983 }
984 #endif
985
986 inval:
987 __trace_probe_log_err(ctx->offset, err);
988 return -EINVAL;
989 }
990
str_to_immediate(char * str,unsigned long * imm)991 static int str_to_immediate(char *str, unsigned long *imm)
992 {
993 if (isdigit(str[0]))
994 return kstrtoul(str, 0, imm);
995 else if (str[0] == '-')
996 return kstrtol(str, 0, (long *)imm);
997 else if (str[0] == '+')
998 return kstrtol(str + 1, 0, (long *)imm);
999 return -EINVAL;
1000 }
1001
__parse_imm_string(char * str,char ** pbuf,int offs)1002 static int __parse_imm_string(char *str, char **pbuf, int offs)
1003 {
1004 size_t len = strlen(str);
1005
1006 if (str[len - 1] != '"') {
1007 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1008 return -EINVAL;
1009 }
1010 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1011 if (!*pbuf)
1012 return -ENOMEM;
1013 return 0;
1014 }
1015
1016 /* Recursive argument parser */
1017 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)1018 parse_probe_arg(char *arg, const struct fetch_type *type,
1019 struct fetch_insn **pcode, struct fetch_insn *end,
1020 struct traceprobe_parse_context *ctx)
1021 {
1022 struct fetch_insn *code = *pcode;
1023 unsigned long param;
1024 int deref = FETCH_OP_DEREF;
1025 long offset = 0;
1026 char *tmp;
1027 int ret = 0;
1028
1029 switch (arg[0]) {
1030 case '$':
1031 ret = parse_probe_vars(arg, type, pcode, end, ctx);
1032 break;
1033
1034 case '%': /* named register */
1035 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1036 /* eprobe and fprobe do not handle registers */
1037 trace_probe_log_err(ctx->offset, BAD_VAR);
1038 break;
1039 }
1040 ret = regs_query_register_offset(arg + 1);
1041 if (ret >= 0) {
1042 code->op = FETCH_OP_REG;
1043 code->param = (unsigned int)ret;
1044 ret = 0;
1045 } else
1046 trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1047 break;
1048
1049 case '@': /* memory, file-offset or symbol */
1050 if (isdigit(arg[1])) {
1051 ret = kstrtoul(arg + 1, 0, ¶m);
1052 if (ret) {
1053 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1054 break;
1055 }
1056 /* load address */
1057 code->op = FETCH_OP_IMM;
1058 code->immediate = param;
1059 } else if (arg[1] == '+') {
1060 /* kprobes don't support file offsets */
1061 if (ctx->flags & TPARG_FL_KERNEL) {
1062 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1063 return -EINVAL;
1064 }
1065 ret = kstrtol(arg + 2, 0, &offset);
1066 if (ret) {
1067 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1068 break;
1069 }
1070
1071 code->op = FETCH_OP_FOFFS;
1072 code->immediate = (unsigned long)offset; // imm64?
1073 } else {
1074 /* uprobes don't support symbols */
1075 if (!(ctx->flags & TPARG_FL_KERNEL)) {
1076 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1077 return -EINVAL;
1078 }
1079 /* Preserve symbol for updating */
1080 code->op = FETCH_NOP_SYMBOL;
1081 code->data = kstrdup(arg + 1, GFP_KERNEL);
1082 if (!code->data)
1083 return -ENOMEM;
1084 if (++code == end) {
1085 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1086 return -EINVAL;
1087 }
1088 code->op = FETCH_OP_IMM;
1089 code->immediate = 0;
1090 }
1091 /* These are fetching from memory */
1092 if (++code == end) {
1093 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1094 return -EINVAL;
1095 }
1096 *pcode = code;
1097 code->op = FETCH_OP_DEREF;
1098 code->offset = offset;
1099 break;
1100
1101 case '+': /* deref memory */
1102 case '-':
1103 if (arg[1] == 'u') {
1104 deref = FETCH_OP_UDEREF;
1105 arg[1] = arg[0];
1106 arg++;
1107 }
1108 if (arg[0] == '+')
1109 arg++; /* Skip '+', because kstrtol() rejects it. */
1110 tmp = strchr(arg, '(');
1111 if (!tmp) {
1112 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1113 return -EINVAL;
1114 }
1115 *tmp = '\0';
1116 ret = kstrtol(arg, 0, &offset);
1117 if (ret) {
1118 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1119 break;
1120 }
1121 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1122 arg = tmp + 1;
1123 tmp = strrchr(arg, ')');
1124 if (!tmp) {
1125 trace_probe_log_err(ctx->offset + strlen(arg),
1126 DEREF_OPEN_BRACE);
1127 return -EINVAL;
1128 } else {
1129 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1130 int cur_offs = ctx->offset;
1131
1132 *tmp = '\0';
1133 ret = parse_probe_arg(arg, t2, &code, end, ctx);
1134 if (ret)
1135 break;
1136 ctx->offset = cur_offs;
1137 if (code->op == FETCH_OP_COMM ||
1138 code->op == FETCH_OP_DATA) {
1139 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1140 return -EINVAL;
1141 }
1142 if (++code == end) {
1143 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1144 return -EINVAL;
1145 }
1146 *pcode = code;
1147
1148 code->op = deref;
1149 code->offset = offset;
1150 /* Reset the last type if used */
1151 ctx->last_type = NULL;
1152 }
1153 break;
1154 case '\\': /* Immediate value */
1155 if (arg[1] == '"') { /* Immediate string */
1156 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1157 if (ret)
1158 break;
1159 code->op = FETCH_OP_DATA;
1160 code->data = tmp;
1161 } else {
1162 ret = str_to_immediate(arg + 1, &code->immediate);
1163 if (ret)
1164 trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1165 else
1166 code->op = FETCH_OP_IMM;
1167 }
1168 break;
1169 default:
1170 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
1171 if (!tparg_is_function_entry(ctx->flags) &&
1172 !tparg_is_function_return(ctx->flags)) {
1173 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1174 return -EINVAL;
1175 }
1176 ret = parse_btf_arg(arg, pcode, end, ctx);
1177 break;
1178 }
1179 }
1180 if (!ret && code->op == FETCH_OP_NOP) {
1181 /* Parsed, but do not find fetch method */
1182 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1183 ret = -EINVAL;
1184 }
1185 return ret;
1186 }
1187
1188 /* 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)1189 static int __parse_bitfield_probe_arg(const char *bf,
1190 const struct fetch_type *t,
1191 struct fetch_insn **pcode)
1192 {
1193 struct fetch_insn *code = *pcode;
1194 unsigned long bw, bo;
1195 char *tail;
1196
1197 if (*bf != 'b')
1198 return 0;
1199
1200 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
1201
1202 if (bw == 0 || *tail != '@')
1203 return -EINVAL;
1204
1205 bf = tail + 1;
1206 bo = simple_strtoul(bf, &tail, 0);
1207
1208 if (tail == bf || *tail != '/')
1209 return -EINVAL;
1210 code++;
1211 if (code->op != FETCH_OP_NOP)
1212 return -EINVAL;
1213 *pcode = code;
1214
1215 code->op = FETCH_OP_MOD_BF;
1216 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1217 code->rshift = BYTES_TO_BITS(t->size) - bw;
1218 code->basesize = t->size;
1219
1220 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1221 }
1222
1223 /* Split type part from @arg and return it. */
parse_probe_arg_type(char * arg,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1224 static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
1225 struct traceprobe_parse_context *ctx)
1226 {
1227 char *t = NULL, *t2, *t3;
1228 int offs;
1229
1230 t = strchr(arg, ':');
1231 if (t) {
1232 *t++ = '\0';
1233 t2 = strchr(t, '[');
1234 if (t2) {
1235 *t2++ = '\0';
1236 t3 = strchr(t2, ']');
1237 if (!t3) {
1238 offs = t2 + strlen(t2) - arg;
1239
1240 trace_probe_log_err(ctx->offset + offs,
1241 ARRAY_NO_CLOSE);
1242 return ERR_PTR(-EINVAL);
1243 } else if (t3[1] != '\0') {
1244 trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1245 BAD_ARRAY_SUFFIX);
1246 return ERR_PTR(-EINVAL);
1247 }
1248 *t3 = '\0';
1249 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1250 trace_probe_log_err(ctx->offset + t2 - arg,
1251 BAD_ARRAY_NUM);
1252 return ERR_PTR(-EINVAL);
1253 }
1254 if (parg->count > MAX_ARRAY_LEN) {
1255 trace_probe_log_err(ctx->offset + t2 - arg,
1256 ARRAY_TOO_BIG);
1257 return ERR_PTR(-EINVAL);
1258 }
1259 }
1260 }
1261 offs = t ? t - arg : 0;
1262
1263 /*
1264 * Since $comm and immediate string can not be dereferenced,
1265 * we can find those by strcmp. But ignore for eprobes.
1266 */
1267 if (!(ctx->flags & TPARG_FL_TEVENT) &&
1268 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1269 strncmp(arg, "\\\"", 2) == 0)) {
1270 /* The type of $comm must be "string", and not an array type. */
1271 if (parg->count || (t && strcmp(t, "string"))) {
1272 trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
1273 return ERR_PTR(-EINVAL);
1274 }
1275 parg->type = find_fetch_type("string", ctx->flags);
1276 } else
1277 parg->type = find_fetch_type(t, ctx->flags);
1278
1279 if (!parg->type) {
1280 trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
1281 return ERR_PTR(-EINVAL);
1282 }
1283
1284 return t;
1285 }
1286
1287 /* 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)1288 static int finalize_fetch_insn(struct fetch_insn *code,
1289 struct probe_arg *parg,
1290 char *type,
1291 int type_offset,
1292 struct traceprobe_parse_context *ctx)
1293 {
1294 struct fetch_insn *scode;
1295 int ret;
1296
1297 /* Store operation */
1298 if (parg->type->is_string) {
1299 /* Check bad combination of the type and the last fetch_insn. */
1300 if (!strcmp(parg->type->name, "symstr")) {
1301 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1302 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1303 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1304 trace_probe_log_err(ctx->offset + type_offset,
1305 BAD_SYMSTRING);
1306 return -EINVAL;
1307 }
1308 } else {
1309 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1310 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1311 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1312 trace_probe_log_err(ctx->offset + type_offset,
1313 BAD_STRING);
1314 return -EINVAL;
1315 }
1316 }
1317
1318 if (!strcmp(parg->type->name, "symstr") ||
1319 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1320 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1321 parg->count) {
1322 /*
1323 * IMM, DATA and COMM is pointing actual address, those
1324 * must be kept, and if parg->count != 0, this is an
1325 * array of string pointers instead of string address
1326 * itself.
1327 * For the symstr, it doesn't need to dereference, thus
1328 * it just get the value.
1329 */
1330 code++;
1331 if (code->op != FETCH_OP_NOP) {
1332 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1333 return -EINVAL;
1334 }
1335 }
1336
1337 /* If op == DEREF, replace it with STRING */
1338 if (!strcmp(parg->type->name, "ustring") ||
1339 code->op == FETCH_OP_UDEREF)
1340 code->op = FETCH_OP_ST_USTRING;
1341 else if (!strcmp(parg->type->name, "symstr"))
1342 code->op = FETCH_OP_ST_SYMSTR;
1343 else
1344 code->op = FETCH_OP_ST_STRING;
1345 code->size = parg->type->size;
1346 parg->dynamic = true;
1347 } else if (code->op == FETCH_OP_DEREF) {
1348 code->op = FETCH_OP_ST_MEM;
1349 code->size = parg->type->size;
1350 } else if (code->op == FETCH_OP_UDEREF) {
1351 code->op = FETCH_OP_ST_UMEM;
1352 code->size = parg->type->size;
1353 } else {
1354 code++;
1355 if (code->op != FETCH_OP_NOP) {
1356 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1357 return -E2BIG;
1358 }
1359 code->op = FETCH_OP_ST_RAW;
1360 code->size = parg->type->size;
1361 }
1362
1363 /* Save storing fetch_insn. */
1364 scode = code;
1365
1366 /* Modify operation */
1367 if (type != NULL) {
1368 /* Bitfield needs a special fetch_insn. */
1369 ret = __parse_bitfield_probe_arg(type, parg->type, &code);
1370 if (ret) {
1371 trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
1372 return ret;
1373 }
1374 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1375 ctx->last_type) {
1376 /* If user not specified the type, try parsing BTF bitfield. */
1377 ret = parse_btf_bitfield(&code, ctx);
1378 if (ret)
1379 return ret;
1380 }
1381
1382 /* Loop(Array) operation */
1383 if (parg->count) {
1384 if (scode->op != FETCH_OP_ST_MEM &&
1385 scode->op != FETCH_OP_ST_STRING &&
1386 scode->op != FETCH_OP_ST_USTRING) {
1387 trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
1388 return -EINVAL;
1389 }
1390 code++;
1391 if (code->op != FETCH_OP_NOP) {
1392 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1393 return -E2BIG;
1394 }
1395 code->op = FETCH_OP_LP_ARRAY;
1396 code->param = parg->count;
1397 }
1398
1399 /* Finalize the fetch_insn array. */
1400 code++;
1401 code->op = FETCH_OP_END;
1402
1403 return 0;
1404 }
1405
1406 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1407 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1408 struct probe_arg *parg,
1409 struct traceprobe_parse_context *ctx)
1410 {
1411 struct fetch_insn *code, *tmp = NULL;
1412 char *type, *arg __free(kfree) = NULL;
1413 int ret, len;
1414
1415 len = strlen(argv);
1416 if (len > MAX_ARGSTR_LEN) {
1417 trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1418 return -E2BIG;
1419 } else if (len == 0) {
1420 trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1421 return -EINVAL;
1422 }
1423
1424 arg = kstrdup(argv, GFP_KERNEL);
1425 if (!arg)
1426 return -ENOMEM;
1427
1428 parg->comm = kstrdup(arg, GFP_KERNEL);
1429 if (!parg->comm)
1430 return -ENOMEM;
1431
1432 type = parse_probe_arg_type(arg, parg, ctx);
1433 if (IS_ERR(type))
1434 return PTR_ERR(type);
1435
1436 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
1437 if (!code)
1438 return -ENOMEM;
1439 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1440
1441 ctx->last_type = NULL;
1442 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1443 ctx);
1444 if (ret < 0)
1445 goto fail;
1446
1447 /* Update storing type if BTF is available */
1448 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1449 ctx->last_type) {
1450 if (!type) {
1451 parg->type = find_fetch_type_from_btf_type(ctx);
1452 } else if (strstr(type, "string")) {
1453 ret = check_prepare_btf_string_fetch(type, &code, ctx);
1454 if (ret)
1455 goto fail;
1456 }
1457 }
1458 parg->offset = *size;
1459 *size += parg->type->size * (parg->count ?: 1);
1460
1461 if (parg->count) {
1462 len = strlen(parg->type->fmttype) + 6;
1463 parg->fmt = kmalloc(len, GFP_KERNEL);
1464 if (!parg->fmt) {
1465 ret = -ENOMEM;
1466 goto fail;
1467 }
1468 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1469 parg->count);
1470 }
1471
1472 ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
1473 if (ret < 0)
1474 goto fail;
1475
1476 for (; code < tmp + FETCH_INSN_MAX; code++)
1477 if (code->op == FETCH_OP_END)
1478 break;
1479 /* Shrink down the code buffer */
1480 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1481 if (!parg->code)
1482 ret = -ENOMEM;
1483 else
1484 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1485
1486 fail:
1487 if (ret < 0) {
1488 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1489 if (code->op == FETCH_NOP_SYMBOL ||
1490 code->op == FETCH_OP_DATA)
1491 kfree(code->data);
1492 }
1493 kfree(tmp);
1494
1495 return ret;
1496 }
1497
1498 /* 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)1499 static int traceprobe_conflict_field_name(const char *name,
1500 struct probe_arg *args, int narg)
1501 {
1502 int i;
1503
1504 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1505 if (strcmp(reserved_field_names[i], name) == 0)
1506 return 1;
1507
1508 for (i = 0; i < narg; i++)
1509 if (strcmp(args[i].name, name) == 0)
1510 return 1;
1511
1512 return 0;
1513 }
1514
generate_probe_arg_name(const char * arg,int idx)1515 static char *generate_probe_arg_name(const char *arg, int idx)
1516 {
1517 char *name = NULL;
1518 const char *end;
1519
1520 /*
1521 * If argument name is omitted, try arg as a name (BTF variable)
1522 * or "argN".
1523 */
1524 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1525 end = strchr(arg, ':');
1526 if (!end)
1527 end = arg + strlen(arg);
1528
1529 name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1530 if (!name || !is_good_name(name)) {
1531 kfree(name);
1532 name = NULL;
1533 }
1534 }
1535
1536 if (!name)
1537 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1538
1539 return name;
1540 }
1541
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,struct traceprobe_parse_context * ctx)1542 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1543 struct traceprobe_parse_context *ctx)
1544 {
1545 struct probe_arg *parg = &tp->args[i];
1546 const char *body;
1547
1548 ctx->tp = tp;
1549 body = strchr(arg, '=');
1550 if (body) {
1551 if (body - arg > MAX_ARG_NAME_LEN) {
1552 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1553 return -EINVAL;
1554 } else if (body == arg) {
1555 trace_probe_log_err(0, NO_ARG_NAME);
1556 return -EINVAL;
1557 }
1558 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1559 body++;
1560 } else {
1561 parg->name = generate_probe_arg_name(arg, i);
1562 body = arg;
1563 }
1564 if (!parg->name)
1565 return -ENOMEM;
1566
1567 if (!is_good_name(parg->name)) {
1568 trace_probe_log_err(0, BAD_ARG_NAME);
1569 return -EINVAL;
1570 }
1571 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1572 trace_probe_log_err(0, USED_ARG_NAME);
1573 return -EINVAL;
1574 }
1575 ctx->offset = body - arg;
1576 /* Parse fetch argument */
1577 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1578 }
1579
traceprobe_free_probe_arg(struct probe_arg * arg)1580 void traceprobe_free_probe_arg(struct probe_arg *arg)
1581 {
1582 struct fetch_insn *code = arg->code;
1583
1584 while (code && code->op != FETCH_OP_END) {
1585 if (code->op == FETCH_NOP_SYMBOL ||
1586 code->op == FETCH_OP_DATA)
1587 kfree(code->data);
1588 code++;
1589 }
1590 kfree(arg->code);
1591 kfree(arg->name);
1592 kfree(arg->comm);
1593 kfree(arg->fmt);
1594 }
1595
argv_has_var_arg(int argc,const char * argv[],int * args_idx,struct traceprobe_parse_context * ctx)1596 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1597 struct traceprobe_parse_context *ctx)
1598 {
1599 int i, found = 0;
1600
1601 for (i = 0; i < argc; i++)
1602 if (str_has_prefix(argv[i], "$arg")) {
1603 trace_probe_log_set_index(i + 2);
1604
1605 if (!tparg_is_function_entry(ctx->flags) &&
1606 !tparg_is_function_return(ctx->flags)) {
1607 trace_probe_log_err(0, NOFENTRY_ARGS);
1608 return -EINVAL;
1609 }
1610
1611 if (isdigit(argv[i][4])) {
1612 found = 1;
1613 continue;
1614 }
1615
1616 if (argv[i][4] != '*') {
1617 trace_probe_log_err(0, BAD_VAR);
1618 return -EINVAL;
1619 }
1620
1621 if (*args_idx >= 0 && *args_idx < argc) {
1622 trace_probe_log_err(0, DOUBLE_ARGS);
1623 return -EINVAL;
1624 }
1625 found = 1;
1626 *args_idx = i;
1627 }
1628
1629 return found;
1630 }
1631
sprint_nth_btf_arg(int idx,const char * type,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1632 static int sprint_nth_btf_arg(int idx, const char *type,
1633 char *buf, int bufsize,
1634 struct traceprobe_parse_context *ctx)
1635 {
1636 const char *name;
1637 int ret;
1638
1639 if (idx >= ctx->nr_params) {
1640 trace_probe_log_err(0, NO_BTFARG);
1641 return -ENOENT;
1642 }
1643 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1644 if (!name) {
1645 trace_probe_log_err(0, NO_BTF_ENTRY);
1646 return -ENOENT;
1647 }
1648 ret = snprintf(buf, bufsize, "%s%s", name, type);
1649 if (ret >= bufsize) {
1650 trace_probe_log_err(0, ARGS_2LONG);
1651 return -E2BIG;
1652 }
1653 return ret;
1654 }
1655
1656 /* 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)1657 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1658 int *new_argc, char *buf, int bufsize,
1659 struct traceprobe_parse_context *ctx)
1660 {
1661 const struct btf_param *params = NULL;
1662 int i, j, n, used, ret, args_idx = -1;
1663 const char **new_argv __free(kfree) = NULL;
1664
1665 ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1666 if (ret < 0)
1667 return ERR_PTR(ret);
1668
1669 if (!ret) {
1670 *new_argc = argc;
1671 return NULL;
1672 }
1673
1674 ret = query_btf_context(ctx);
1675 if (ret < 0 || ctx->nr_params == 0) {
1676 if (args_idx != -1) {
1677 /* $arg* requires BTF info */
1678 trace_probe_log_err(0, NOSUP_BTFARG);
1679 return (const char **)params;
1680 }
1681 *new_argc = argc;
1682 return NULL;
1683 }
1684
1685 if (args_idx >= 0)
1686 *new_argc = argc + ctx->nr_params - 1;
1687 else
1688 *new_argc = argc;
1689
1690 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1691 if (!new_argv)
1692 return ERR_PTR(-ENOMEM);
1693
1694 used = 0;
1695 for (i = 0, j = 0; i < argc; i++) {
1696 trace_probe_log_set_index(i + 2);
1697 if (i == args_idx) {
1698 for (n = 0; n < ctx->nr_params; n++) {
1699 ret = sprint_nth_btf_arg(n, "", buf + used,
1700 bufsize - used, ctx);
1701 if (ret < 0)
1702 return ERR_PTR(ret);
1703
1704 new_argv[j++] = buf + used;
1705 used += ret + 1;
1706 }
1707 continue;
1708 }
1709
1710 if (str_has_prefix(argv[i], "$arg")) {
1711 char *type = NULL;
1712
1713 n = simple_strtoul(argv[i] + 4, &type, 10);
1714 if (type && !(*type == ':' || *type == '\0')) {
1715 trace_probe_log_err(0, BAD_VAR);
1716 return ERR_PTR(-ENOENT);
1717 }
1718 /* Note: $argN starts from $arg1 */
1719 ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1720 bufsize - used, ctx);
1721 if (ret < 0)
1722 return ERR_PTR(ret);
1723 new_argv[j++] = buf + used;
1724 used += ret + 1;
1725 } else
1726 new_argv[j++] = argv[i];
1727 }
1728
1729 return_ptr(new_argv);
1730 }
1731
1732 /* @buf: *buf must be equal to NULL. Caller must to free *buf */
traceprobe_expand_dentry_args(int argc,const char * argv[],char ** buf)1733 int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
1734 {
1735 int i, used, ret;
1736 const int bufsize = MAX_DENTRY_ARGS_LEN;
1737 char *tmpbuf __free(kfree) = NULL;
1738
1739 if (*buf)
1740 return -EINVAL;
1741
1742 used = 0;
1743 for (i = 0; i < argc; i++) {
1744 char *tmp __free(kfree) = NULL;
1745 char *equal;
1746 size_t arg_len;
1747
1748 if (!glob_match("*:%p[dD]", argv[i]))
1749 continue;
1750
1751 if (!tmpbuf) {
1752 tmpbuf = kmalloc(bufsize, GFP_KERNEL);
1753 if (!tmpbuf)
1754 return -ENOMEM;
1755 }
1756
1757 tmp = kstrdup(argv[i], GFP_KERNEL);
1758 if (!tmp)
1759 return -ENOMEM;
1760
1761 equal = strchr(tmp, '=');
1762 if (equal)
1763 *equal = '\0';
1764 arg_len = strlen(argv[i]);
1765 tmp[arg_len - 4] = '\0';
1766 if (argv[i][arg_len - 1] == 'd')
1767 ret = snprintf(tmpbuf + used, bufsize - used,
1768 "%s%s+0x0(+0x%zx(%s)):string",
1769 equal ? tmp : "", equal ? "=" : "",
1770 offsetof(struct dentry, d_name.name),
1771 equal ? equal + 1 : tmp);
1772 else
1773 ret = snprintf(tmpbuf + used, bufsize - used,
1774 "%s%s+0x0(+0x%zx(+0x%zx(%s))):string",
1775 equal ? tmp : "", equal ? "=" : "",
1776 offsetof(struct dentry, d_name.name),
1777 offsetof(struct file, f_path.dentry),
1778 equal ? equal + 1 : tmp);
1779
1780 if (ret >= bufsize - used)
1781 return -ENOMEM;
1782 argv[i] = tmpbuf + used;
1783 used += ret + 1;
1784 }
1785
1786 *buf = no_free_ptr(tmpbuf);
1787 return 0;
1788 }
1789
traceprobe_finish_parse(struct traceprobe_parse_context * ctx)1790 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1791 {
1792 clear_btf_context(ctx);
1793 }
1794
traceprobe_update_arg(struct probe_arg * arg)1795 int traceprobe_update_arg(struct probe_arg *arg)
1796 {
1797 struct fetch_insn *code = arg->code;
1798 long offset;
1799 char *tmp;
1800 char c;
1801 int ret = 0;
1802
1803 while (code && code->op != FETCH_OP_END) {
1804 if (code->op == FETCH_NOP_SYMBOL) {
1805 if (code[1].op != FETCH_OP_IMM)
1806 return -EINVAL;
1807
1808 tmp = strpbrk(code->data, "+-");
1809 if (tmp)
1810 c = *tmp;
1811 ret = traceprobe_split_symbol_offset(code->data,
1812 &offset);
1813 if (ret)
1814 return ret;
1815
1816 code[1].immediate =
1817 (unsigned long)kallsyms_lookup_name(code->data);
1818 if (tmp)
1819 *tmp = c;
1820 if (!code[1].immediate)
1821 return -ENOENT;
1822 code[1].immediate += offset;
1823 }
1824 code++;
1825 }
1826 return 0;
1827 }
1828
1829 /* When len=0, we just calculate the needed length */
1830 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)1831 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1832 enum probe_print_type ptype)
1833 {
1834 struct probe_arg *parg;
1835 int i, j;
1836 int pos = 0;
1837 const char *fmt, *arg;
1838
1839 switch (ptype) {
1840 case PROBE_PRINT_NORMAL:
1841 fmt = "(%lx)";
1842 arg = ", REC->" FIELD_STRING_IP;
1843 break;
1844 case PROBE_PRINT_RETURN:
1845 fmt = "(%lx <- %lx)";
1846 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1847 break;
1848 case PROBE_PRINT_EVENT:
1849 fmt = "";
1850 arg = "";
1851 break;
1852 default:
1853 WARN_ON_ONCE(1);
1854 return 0;
1855 }
1856
1857 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1858
1859 for (i = 0; i < tp->nr_args; i++) {
1860 parg = tp->args + i;
1861 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1862 if (parg->count) {
1863 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1864 parg->type->fmt);
1865 for (j = 1; j < parg->count; j++)
1866 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1867 parg->type->fmt);
1868 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1869 } else
1870 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1871 parg->type->fmt);
1872 }
1873
1874 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1875
1876 for (i = 0; i < tp->nr_args; i++) {
1877 parg = tp->args + i;
1878 if (parg->count) {
1879 if (parg->type->is_string)
1880 fmt = ", __get_str(%s[%d])";
1881 else
1882 fmt = ", REC->%s[%d]";
1883 for (j = 0; j < parg->count; j++)
1884 pos += snprintf(buf + pos, LEN_OR_ZERO,
1885 fmt, parg->name, j);
1886 } else {
1887 if (parg->type->is_string)
1888 fmt = ", __get_str(%s)";
1889 else
1890 fmt = ", REC->%s";
1891 pos += snprintf(buf + pos, LEN_OR_ZERO,
1892 fmt, parg->name);
1893 }
1894 }
1895
1896 /* return the length of print_fmt */
1897 return pos;
1898 }
1899 #undef LEN_OR_ZERO
1900
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)1901 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1902 {
1903 struct trace_event_call *call = trace_probe_event_call(tp);
1904 int len;
1905 char *print_fmt;
1906
1907 /* First: called with 0 length to calculate the needed length */
1908 len = __set_print_fmt(tp, NULL, 0, ptype);
1909 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1910 if (!print_fmt)
1911 return -ENOMEM;
1912
1913 /* Second: actually write the @print_fmt */
1914 __set_print_fmt(tp, print_fmt, len + 1, ptype);
1915 call->print_fmt = print_fmt;
1916
1917 return 0;
1918 }
1919
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)1920 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1921 size_t offset, struct trace_probe *tp)
1922 {
1923 int ret, i;
1924
1925 /* Set argument names as fields */
1926 for (i = 0; i < tp->nr_args; i++) {
1927 struct probe_arg *parg = &tp->args[i];
1928 const char *fmt = parg->type->fmttype;
1929 int size = parg->type->size;
1930
1931 if (parg->fmt)
1932 fmt = parg->fmt;
1933 if (parg->count)
1934 size *= parg->count;
1935 ret = trace_define_field(event_call, fmt, parg->name,
1936 offset + parg->offset, size,
1937 parg->type->is_signed,
1938 FILTER_OTHER);
1939 if (ret)
1940 return ret;
1941 }
1942 return 0;
1943 }
1944
trace_probe_event_free(struct trace_probe_event * tpe)1945 static void trace_probe_event_free(struct trace_probe_event *tpe)
1946 {
1947 kfree(tpe->class.system);
1948 kfree(tpe->call.name);
1949 kfree(tpe->call.print_fmt);
1950 kfree(tpe);
1951 }
1952
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)1953 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1954 {
1955 if (trace_probe_has_sibling(tp))
1956 return -EBUSY;
1957
1958 list_del_init(&tp->list);
1959 trace_probe_event_free(tp->event);
1960
1961 tp->event = to->event;
1962 list_add_tail(&tp->list, trace_probe_probe_list(to));
1963
1964 return 0;
1965 }
1966
trace_probe_unlink(struct trace_probe * tp)1967 void trace_probe_unlink(struct trace_probe *tp)
1968 {
1969 list_del_init(&tp->list);
1970 if (list_empty(trace_probe_probe_list(tp)))
1971 trace_probe_event_free(tp->event);
1972 tp->event = NULL;
1973 }
1974
trace_probe_cleanup(struct trace_probe * tp)1975 void trace_probe_cleanup(struct trace_probe *tp)
1976 {
1977 int i;
1978
1979 for (i = 0; i < tp->nr_args; i++)
1980 traceprobe_free_probe_arg(&tp->args[i]);
1981
1982 if (tp->entry_arg) {
1983 kfree(tp->entry_arg->code);
1984 kfree(tp->entry_arg);
1985 tp->entry_arg = NULL;
1986 }
1987
1988 if (tp->event)
1989 trace_probe_unlink(tp);
1990 }
1991
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter,int nargs)1992 int trace_probe_init(struct trace_probe *tp, const char *event,
1993 const char *group, bool alloc_filter, int nargs)
1994 {
1995 struct trace_event_call *call;
1996 size_t size = sizeof(struct trace_probe_event);
1997 int ret = 0;
1998
1999 if (!event || !group)
2000 return -EINVAL;
2001
2002 if (alloc_filter)
2003 size += sizeof(struct trace_uprobe_filter);
2004
2005 tp->event = kzalloc(size, GFP_KERNEL);
2006 if (!tp->event)
2007 return -ENOMEM;
2008
2009 INIT_LIST_HEAD(&tp->event->files);
2010 INIT_LIST_HEAD(&tp->event->class.fields);
2011 INIT_LIST_HEAD(&tp->event->probes);
2012 INIT_LIST_HEAD(&tp->list);
2013 list_add(&tp->list, &tp->event->probes);
2014
2015 call = trace_probe_event_call(tp);
2016 call->class = &tp->event->class;
2017 call->name = kstrdup(event, GFP_KERNEL);
2018 if (!call->name) {
2019 ret = -ENOMEM;
2020 goto error;
2021 }
2022
2023 tp->event->class.system = kstrdup(group, GFP_KERNEL);
2024 if (!tp->event->class.system) {
2025 ret = -ENOMEM;
2026 goto error;
2027 }
2028
2029 tp->nr_args = nargs;
2030 /* Make sure pointers in args[] are NULL */
2031 if (nargs)
2032 memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
2033
2034 return 0;
2035
2036 error:
2037 trace_probe_cleanup(tp);
2038 return ret;
2039 }
2040
2041 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)2042 find_trace_event_call(const char *system, const char *event_name)
2043 {
2044 struct trace_event_call *tp_event;
2045 const char *name;
2046
2047 list_for_each_entry(tp_event, &ftrace_events, list) {
2048 if (!tp_event->class->system ||
2049 strcmp(system, tp_event->class->system))
2050 continue;
2051 name = trace_event_name(tp_event);
2052 if (!name || strcmp(event_name, name))
2053 continue;
2054 return tp_event;
2055 }
2056
2057 return NULL;
2058 }
2059
trace_probe_register_event_call(struct trace_probe * tp)2060 int trace_probe_register_event_call(struct trace_probe *tp)
2061 {
2062 struct trace_event_call *call = trace_probe_event_call(tp);
2063 int ret;
2064
2065 lockdep_assert_held(&event_mutex);
2066
2067 if (find_trace_event_call(trace_probe_group_name(tp),
2068 trace_probe_name(tp)))
2069 return -EEXIST;
2070
2071 ret = register_trace_event(&call->event);
2072 if (!ret)
2073 return -ENODEV;
2074
2075 ret = trace_add_event_call(call);
2076 if (ret)
2077 unregister_trace_event(&call->event);
2078
2079 return ret;
2080 }
2081
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)2082 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2083 {
2084 struct event_file_link *link;
2085
2086 link = kmalloc(sizeof(*link), GFP_KERNEL);
2087 if (!link)
2088 return -ENOMEM;
2089
2090 link->file = file;
2091 INIT_LIST_HEAD(&link->list);
2092 list_add_tail_rcu(&link->list, &tp->event->files);
2093 trace_probe_set_flag(tp, TP_FLAG_TRACE);
2094 return 0;
2095 }
2096
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)2097 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2098 struct trace_event_file *file)
2099 {
2100 struct event_file_link *link;
2101
2102 trace_probe_for_each_link(link, tp) {
2103 if (link->file == file)
2104 return link;
2105 }
2106
2107 return NULL;
2108 }
2109
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)2110 int trace_probe_remove_file(struct trace_probe *tp,
2111 struct trace_event_file *file)
2112 {
2113 struct event_file_link *link;
2114
2115 link = trace_probe_get_file_link(tp, file);
2116 if (!link)
2117 return -ENOENT;
2118
2119 list_del_rcu(&link->list);
2120 kvfree_rcu_mightsleep(link);
2121
2122 if (list_empty(&tp->event->files))
2123 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2124
2125 return 0;
2126 }
2127
2128 /*
2129 * Return the smallest index of different type argument (start from 1).
2130 * If all argument types and name are same, return 0.
2131 */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)2132 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2133 {
2134 int i;
2135
2136 /* In case of more arguments */
2137 if (a->nr_args < b->nr_args)
2138 return a->nr_args + 1;
2139 if (a->nr_args > b->nr_args)
2140 return b->nr_args + 1;
2141
2142 for (i = 0; i < a->nr_args; i++) {
2143 if ((b->nr_args <= i) ||
2144 ((a->args[i].type != b->args[i].type) ||
2145 (a->args[i].count != b->args[i].count) ||
2146 strcmp(a->args[i].name, b->args[i].name)))
2147 return i + 1;
2148 }
2149
2150 return 0;
2151 }
2152
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)2153 bool trace_probe_match_command_args(struct trace_probe *tp,
2154 int argc, const char **argv)
2155 {
2156 char buf[MAX_ARGSTR_LEN + 1];
2157 int i;
2158
2159 if (tp->nr_args < argc)
2160 return false;
2161
2162 for (i = 0; i < argc; i++) {
2163 snprintf(buf, sizeof(buf), "%s=%s",
2164 tp->args[i].name, tp->args[i].comm);
2165 if (strcmp(buf, argv[i]))
2166 return false;
2167 }
2168 return true;
2169 }
2170
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))2171 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2172 {
2173 int argc = 0, ret = 0;
2174 char **argv;
2175
2176 argv = argv_split(GFP_KERNEL, raw_command, &argc);
2177 if (!argv)
2178 return -ENOMEM;
2179
2180 if (argc)
2181 ret = createfn(argc, (const char **)argv);
2182
2183 argv_free(argv);
2184
2185 return ret;
2186 }
2187
trace_probe_print_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)2188 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2189 u8 *data, void *field)
2190 {
2191 void *p;
2192 int i, j;
2193
2194 for (i = 0; i < nr_args; i++) {
2195 struct probe_arg *a = args + i;
2196
2197 trace_seq_printf(s, " %s=", a->name);
2198 if (likely(!a->count)) {
2199 if (!a->type->print(s, data + a->offset, field))
2200 return -ENOMEM;
2201 continue;
2202 }
2203 trace_seq_putc(s, '{');
2204 p = data + a->offset;
2205 for (j = 0; j < a->count; j++) {
2206 if (!a->type->print(s, p, field))
2207 return -ENOMEM;
2208 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2209 p += a->type->size;
2210 }
2211 }
2212 return 0;
2213 }
2214