1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Common code for probe-based Dynamic events.
4 *
5 * This code was copied from kernel/trace/trace_kprobe.c written by
6 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
7 *
8 * Updates to make this generic:
9 * Copyright (C) IBM Corporation, 2010-2011
10 * Author: Srikar Dronamraju
11 */
12 #define pr_fmt(fmt) "trace_probe: " fmt
13
14 #include <linux/bpf.h>
15 #include <linux/fs.h>
16
17 #include "trace_btf.h"
18 #include "trace_probe.h"
19
20 #undef C
21 #define C(a, b) b
22
23 static const char *trace_probe_err_text[] = { ERRORS };
24
25 static const char *reserved_field_names[] = {
26 "common_type",
27 "common_flags",
28 "common_preempt_count",
29 "common_pid",
30 "common_tgid",
31 FIELD_STRING_IP,
32 FIELD_STRING_RETIP,
33 FIELD_STRING_FUNC,
34 };
35
36 /* Printing in basic type function template */
37 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
38 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
39 { \
40 trace_seq_printf(s, fmt, *(type *)data); \
41 return !trace_seq_has_overflowed(s); \
42 } \
43 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
44
45 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
48 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
49 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
53 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
54 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
55 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
56 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
57 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
58
PRINT_TYPE_FUNC_NAME(symbol)59 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
60 {
61 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
62 return !trace_seq_has_overflowed(s);
63 }
64 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
65
66 /* Print type function for string type */
PRINT_TYPE_FUNC_NAME(string)67 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
68 {
69 int len = *(u32 *)data >> 16;
70
71 if (!len)
72 trace_seq_puts(s, FAULT_STRING);
73 else
74 trace_seq_printf(s, "\"%s\"",
75 (const char *)get_loc_data(data, ent));
76 return !trace_seq_has_overflowed(s);
77 }
78
79 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
80
81 /* Fetch type information table */
82 static const struct fetch_type probe_fetch_types[] = {
83 /* Special types */
84 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
85 "__data_loc char[]"),
86 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
87 "__data_loc char[]"),
88 __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
89 "__data_loc char[]"),
90 /* Basic types */
91 ASSIGN_FETCH_TYPE(u8, u8, 0),
92 ASSIGN_FETCH_TYPE(u16, u16, 0),
93 ASSIGN_FETCH_TYPE(u32, u32, 0),
94 ASSIGN_FETCH_TYPE(u64, u64, 0),
95 ASSIGN_FETCH_TYPE(s8, u8, 1),
96 ASSIGN_FETCH_TYPE(s16, u16, 1),
97 ASSIGN_FETCH_TYPE(s32, u32, 1),
98 ASSIGN_FETCH_TYPE(s64, u64, 1),
99 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
100 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
101 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
102 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
103 ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0),
104 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
105
106 ASSIGN_FETCH_TYPE_END
107 };
108
find_fetch_type(const char * type,unsigned long flags)109 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
110 {
111 int i;
112
113 /* Reject the symbol/symstr for uprobes */
114 if (type && (flags & TPARG_FL_USER) &&
115 (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
116 return NULL;
117
118 if (!type)
119 type = DEFAULT_FETCH_TYPE_STR;
120
121 /* Special case: bitfield */
122 if (*type == 'b') {
123 unsigned long bs;
124
125 type = strchr(type, '/');
126 if (!type)
127 goto fail;
128
129 type++;
130 if (kstrtoul(type, 0, &bs))
131 goto fail;
132
133 switch (bs) {
134 case 8:
135 return find_fetch_type("u8", flags);
136 case 16:
137 return find_fetch_type("u16", flags);
138 case 32:
139 return find_fetch_type("u32", flags);
140 case 64:
141 return find_fetch_type("u64", flags);
142 default:
143 goto fail;
144 }
145 }
146
147 for (i = 0; probe_fetch_types[i].name; i++) {
148 if (strcmp(type, probe_fetch_types[i].name) == 0)
149 return &probe_fetch_types[i];
150 }
151
152 fail:
153 return NULL;
154 }
155
156 static struct trace_probe_log trace_probe_log;
157 extern struct mutex dyn_event_ops_mutex;
158
trace_probe_log_init(const char * subsystem,int argc,const char ** argv)159 const char *trace_probe_log_init(const char *subsystem, int argc, const char **argv)
160 {
161 lockdep_assert_held(&dyn_event_ops_mutex);
162
163 trace_probe_log.subsystem = subsystem;
164 trace_probe_log.argc = argc;
165 trace_probe_log.argv = argv;
166 trace_probe_log.index = 0;
167 return subsystem;
168 }
169
trace_probe_log_clear(void)170 void trace_probe_log_clear(void)
171 {
172 lockdep_assert_held(&dyn_event_ops_mutex);
173
174 memset(&trace_probe_log, 0, sizeof(trace_probe_log));
175 }
176
trace_probe_log_set_index(int index)177 void trace_probe_log_set_index(int index)
178 {
179 lockdep_assert_held(&dyn_event_ops_mutex);
180
181 trace_probe_log.index = index;
182 }
183
__trace_probe_log_err(int offset,int err_type)184 void __trace_probe_log_err(int offset, int err_type)
185 {
186 char *command, *p;
187 int i, len = 0, pos = 0;
188
189 lockdep_assert_held(&dyn_event_ops_mutex);
190
191 if (!trace_probe_log.argv)
192 return;
193
194 /* Recalculate the length and allocate buffer */
195 for (i = 0; i < trace_probe_log.argc; i++) {
196 if (i == trace_probe_log.index)
197 pos = len;
198 len += strlen(trace_probe_log.argv[i]) + 1;
199 }
200 command = kzalloc(len, GFP_KERNEL);
201 if (!command)
202 return;
203
204 if (trace_probe_log.index >= trace_probe_log.argc) {
205 /**
206 * Set the error position is next to the last arg + space.
207 * Note that len includes the terminal null and the cursor
208 * appears at pos + 1.
209 */
210 pos = len;
211 offset = 0;
212 }
213
214 /* And make a command string from argv array */
215 p = command;
216 for (i = 0; i < trace_probe_log.argc; i++) {
217 len = strlen(trace_probe_log.argv[i]);
218 memcpy(p, trace_probe_log.argv[i], len);
219 p[len] = ' ';
220 p += len + 1;
221 }
222 *(p - 1) = '\0';
223
224 tracing_log_err(NULL, trace_probe_log.subsystem, command,
225 trace_probe_err_text, err_type, pos + offset);
226
227 kfree(command);
228 }
229
230 /* Split symbol and offset. */
traceprobe_split_symbol_offset(char * symbol,long * offset)231 int traceprobe_split_symbol_offset(char *symbol, long *offset)
232 {
233 char *tmp;
234 int ret;
235
236 if (!offset)
237 return -EINVAL;
238
239 tmp = strpbrk(symbol, "+-");
240 if (tmp) {
241 ret = kstrtol(tmp, 0, offset);
242 if (ret)
243 return ret;
244 *tmp = '\0';
245 } else
246 *offset = 0;
247
248 return 0;
249 }
250
251 /**
252 * traceprobe_parse_event_name() - Parse a string into group and event names
253 * @pevent: A pointer to the string to be parsed.
254 * @pgroup: A pointer to the group name.
255 * @buf: A buffer to store the parsed group name.
256 * @offset: The offset of the string in the original user command, for logging.
257 *
258 * This parses a string with the format `[GROUP/][EVENT]` or `[GROUP.][EVENT]`
259 * (either GROUP or EVENT or both must be specified).
260 * Since the parsed group name is stored in @buf, the caller must ensure @buf
261 * is at least MAX_EVENT_NAME_LEN bytes.
262 *
263 * Return: 0 on success, or -EINVAL on failure.
264 *
265 * If success, *@pevent is updated to point to the event name part of the
266 * original string, or NULL if there is no event name.
267 * Also, *@pgroup is updated to point to the parsed group which is stored
268 * in @buf, or NULL if there is no group name.
269 */
traceprobe_parse_event_name(const char ** pevent,const char ** pgroup,char * buf,int offset)270 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
271 char *buf, int offset)
272 {
273 const char *slash, *event = *pevent;
274 int len;
275
276 slash = strchr(event, '/');
277 if (!slash)
278 slash = strchr(event, '.');
279
280 if (slash) {
281 if (slash == event) {
282 trace_probe_log_err(offset, NO_GROUP_NAME);
283 return -EINVAL;
284 }
285 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
286 trace_probe_log_err(offset, GROUP_TOO_LONG);
287 return -EINVAL;
288 }
289 strscpy(buf, event, slash - event + 1);
290 if (!is_good_system_name(buf)) {
291 trace_probe_log_err(offset, BAD_GROUP_NAME);
292 return -EINVAL;
293 }
294 *pgroup = buf;
295 *pevent = slash + 1;
296 offset += slash - event + 1;
297 event = *pevent;
298 }
299 len = strlen(event);
300 if (len == 0) {
301 if (slash) {
302 *pevent = NULL;
303 return 0;
304 }
305 trace_probe_log_err(offset, NO_EVENT_NAME);
306 return -EINVAL;
307 } else if (len >= MAX_EVENT_NAME_LEN) {
308 trace_probe_log_err(offset, EVENT_TOO_LONG);
309 return -EINVAL;
310 }
311 if (!is_good_name(event)) {
312 trace_probe_log_err(offset, BAD_EVENT_NAME);
313 return -EINVAL;
314 }
315 return 0;
316 }
317
parse_trace_event_arg(char * arg,struct fetch_insn * code,struct traceprobe_parse_context * ctx)318 static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
319 struct traceprobe_parse_context *ctx)
320 {
321 struct ftrace_event_field *field;
322 struct list_head *head;
323
324 head = trace_get_fields(ctx->event);
325 list_for_each_entry(field, head, link) {
326 if (!strcmp(arg, field->name)) {
327 code->op = FETCH_OP_TP_ARG;
328 code->data = field;
329 return 0;
330 }
331 }
332 return -ENOENT;
333 }
334
parse_trace_event(char * arg,struct fetch_insn * code,struct traceprobe_parse_context * ctx)335 static int parse_trace_event(char *arg, struct fetch_insn *code,
336 struct traceprobe_parse_context *ctx)
337 {
338 int ret;
339
340 if (code->data)
341 return -EFAULT;
342 ret = parse_trace_event_arg(arg, code, ctx);
343 if (!ret)
344 return 0;
345 return -EINVAL;
346 }
347
348 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
349
btf_type_int(const struct btf_type * t)350 static u32 btf_type_int(const struct btf_type *t)
351 {
352 return *(u32 *)(t + 1);
353 }
354
btf_type_is_char_ptr(struct btf * btf,const struct btf_type * type)355 static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
356 {
357 const struct btf_type *real_type;
358 u32 intdata;
359 s32 tid;
360
361 real_type = btf_type_skip_modifiers(btf, type->type, &tid);
362 if (!real_type)
363 return false;
364
365 if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
366 return false;
367
368 intdata = btf_type_int(real_type);
369 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
370 && BTF_INT_BITS(intdata) == 8;
371 }
372
btf_type_is_char_array(struct btf * btf,const struct btf_type * type)373 static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
374 {
375 const struct btf_type *real_type;
376 const struct btf_array *array;
377 u32 intdata;
378 s32 tid;
379
380 if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
381 return false;
382
383 array = (const struct btf_array *)(type + 1);
384
385 real_type = btf_type_skip_modifiers(btf, array->type, &tid);
386
387 intdata = btf_type_int(real_type);
388 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
389 && BTF_INT_BITS(intdata) == 8;
390 }
391
ctx_btf(struct traceprobe_parse_context * ctx)392 static struct btf *ctx_btf(struct traceprobe_parse_context *ctx)
393 {
394 return ctx->struct_btf ? : ctx->btf;
395 }
396
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)397 static int check_prepare_btf_string_fetch(char *typename,
398 struct fetch_insn **pcode,
399 struct traceprobe_parse_context *ctx)
400 {
401 struct btf *btf = ctx_btf(ctx);
402
403 if (!btf || !ctx->last_type)
404 return 0;
405
406 /* char [] does not need any change. */
407 if (btf_type_is_char_array(btf, ctx->last_type))
408 return 0;
409
410 /* char * requires dereference the pointer. */
411 if (btf_type_is_char_ptr(btf, ctx->last_type)) {
412 struct fetch_insn *code = *pcode + 1;
413
414 if (code->op == FETCH_OP_END) {
415 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
416 return -E2BIG;
417 }
418 if (typename[0] == 'u')
419 code->op = FETCH_OP_UDEREF;
420 else
421 code->op = FETCH_OP_DEREF;
422 code->offset = 0;
423 *pcode = code;
424 return 0;
425 }
426 /* Other types are not available for string */
427 trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
428 return -EINVAL;
429 }
430
fetch_type_from_btf_type(struct btf * btf,const struct btf_type * type,struct traceprobe_parse_context * ctx)431 static const char *fetch_type_from_btf_type(struct btf *btf,
432 const struct btf_type *type,
433 struct traceprobe_parse_context *ctx)
434 {
435 u32 intdata;
436
437 /* TODO: const char * could be converted as a string */
438 switch (BTF_INFO_KIND(type->info)) {
439 case BTF_KIND_ENUM:
440 /* enum is "int", so convert to "s32" */
441 return "s32";
442 case BTF_KIND_ENUM64:
443 return "s64";
444 case BTF_KIND_PTR:
445 /* pointer will be converted to "x??" */
446 if (IS_ENABLED(CONFIG_64BIT))
447 return "x64";
448 else
449 return "x32";
450 case BTF_KIND_INT:
451 intdata = btf_type_int(type);
452 if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
453 switch (BTF_INT_BITS(intdata)) {
454 case 8:
455 return "s8";
456 case 16:
457 return "s16";
458 case 32:
459 return "s32";
460 case 64:
461 return "s64";
462 }
463 } else { /* unsigned */
464 switch (BTF_INT_BITS(intdata)) {
465 case 8:
466 return "u8";
467 case 16:
468 return "u16";
469 case 32:
470 return "u32";
471 case 64:
472 return "u64";
473 }
474 /* bitfield, size is encoded in the type */
475 ctx->last_bitsize = BTF_INT_BITS(intdata);
476 ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
477 return "u64";
478 }
479 }
480 /* TODO: support other types */
481
482 return NULL;
483 }
484
query_btf_context(struct traceprobe_parse_context * ctx)485 static int query_btf_context(struct traceprobe_parse_context *ctx)
486 {
487 const struct btf_param *param;
488 const struct btf_type *type;
489 struct btf *btf;
490 s32 nr;
491
492 if (ctx->btf)
493 return 0;
494
495 if (!ctx->funcname)
496 return -EINVAL;
497
498 type = btf_find_func_proto(ctx->funcname, &btf);
499 if (!type)
500 return -ENOENT;
501
502 ctx->btf = btf;
503 ctx->proto = type;
504
505 /* ctx->params is optional, since func(void) will not have params. */
506 nr = 0;
507 param = btf_get_func_param(type, &nr);
508 if (!IS_ERR_OR_NULL(param)) {
509 /* Hide the first 'data' argument of tracepoint */
510 if (ctx->flags & TPARG_FL_TPOINT) {
511 nr--;
512 param++;
513 }
514 }
515
516 if (nr > 0) {
517 ctx->nr_params = nr;
518 ctx->params = param;
519 } else {
520 ctx->nr_params = 0;
521 ctx->params = NULL;
522 }
523
524 return 0;
525 }
526
clear_struct_btf(struct traceprobe_parse_context * ctx)527 static void clear_struct_btf(struct traceprobe_parse_context *ctx)
528 {
529 if (ctx->struct_btf) {
530 btf_put(ctx->struct_btf);
531 ctx->struct_btf = NULL;
532 ctx->last_struct = NULL;
533 }
534 }
535
clear_btf_context(struct traceprobe_parse_context * ctx)536 static void clear_btf_context(struct traceprobe_parse_context *ctx)
537 {
538 if (ctx->btf) {
539 btf_put(ctx->btf);
540 ctx->btf = NULL;
541 ctx->proto = NULL;
542 ctx->params = NULL;
543 ctx->nr_params = 0;
544 }
545 }
546
547 /* Return 1 if the field separator is arrow operator ('->') */
split_next_field(char * varname,char ** next_field,struct traceprobe_parse_context * ctx)548 static int split_next_field(char *varname, char **next_field,
549 struct traceprobe_parse_context *ctx)
550 {
551 char *field;
552 int ret = 0;
553
554 field = strpbrk(varname, ".-");
555 if (field) {
556 if (field[0] == '-' && field[1] == '>') {
557 field[0] = '\0';
558 field += 2;
559 ret = 1;
560 } else if (field[0] == '.') {
561 field[0] = '\0';
562 field += 1;
563 } else {
564 trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
565 return -EINVAL;
566 }
567 *next_field = field;
568 }
569
570 return ret;
571 }
572
573 /*
574 * Parse the field of data structure. The @type must be a pointer type
575 * pointing the target data structure type.
576 */
parse_btf_field(char * fieldname,const struct btf_type * type,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)577 static int parse_btf_field(char *fieldname, const struct btf_type *type,
578 struct fetch_insn **pcode, struct fetch_insn *end,
579 struct traceprobe_parse_context *ctx)
580 {
581 struct fetch_insn *code = *pcode;
582 const struct btf_member *field;
583 u32 bitoffs, anon_offs;
584 bool is_struct = ctx->struct_btf != NULL;
585 struct btf *btf = ctx_btf(ctx);
586 char *next;
587 int is_ptr;
588 s32 tid;
589
590 do {
591 if (!is_struct) {
592 /* Outer loop for solving arrow operator ('->') */
593 if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
594 trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
595 return -EINVAL;
596 }
597
598 /* Convert a struct pointer type to a struct type */
599 type = btf_type_skip_modifiers(btf, type->type, &tid);
600 if (!type) {
601 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
602 return -EINVAL;
603 }
604 }
605 /* Only the first type can skip being a pointer */
606 is_struct = false;
607
608 bitoffs = 0;
609 do {
610 /* Inner loop for solving dot operator ('.') */
611 next = NULL;
612 is_ptr = split_next_field(fieldname, &next, ctx);
613 if (is_ptr < 0)
614 return is_ptr;
615
616 anon_offs = 0;
617 field = btf_find_struct_member(btf, type, fieldname,
618 &anon_offs);
619 if (IS_ERR(field)) {
620 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
621 return PTR_ERR(field);
622 }
623 if (!field) {
624 trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
625 return -ENOENT;
626 }
627 /* Add anonymous structure/union offset */
628 bitoffs += anon_offs;
629
630 /* Accumulate the bit-offsets of the dot-connected fields */
631 if (btf_type_kflag(type)) {
632 bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
633 ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
634 } else {
635 bitoffs += field->offset;
636 ctx->last_bitsize = 0;
637 }
638
639 type = btf_type_skip_modifiers(btf, field->type, &tid);
640 if (!type) {
641 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
642 return -EINVAL;
643 }
644
645 ctx->offset += next - fieldname;
646 fieldname = next;
647 } while (!is_ptr && fieldname);
648
649 if (++code == end) {
650 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
651 return -EINVAL;
652 }
653 code->op = FETCH_OP_DEREF; /* TODO: user deref support */
654 code->offset = bitoffs / 8;
655 *pcode = code;
656
657 ctx->last_bitoffs = bitoffs % 8;
658 ctx->last_type = type;
659 } while (fieldname);
660
661 return 0;
662 }
663
664 static int __store_entry_arg(struct trace_probe *tp, int argnum);
665
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)666 static int parse_btf_arg(char *varname,
667 struct fetch_insn **pcode, struct fetch_insn *end,
668 struct traceprobe_parse_context *ctx)
669 {
670 struct fetch_insn *code = *pcode;
671 const struct btf_param *params;
672 const struct btf_type *type;
673 char *field = NULL;
674 int i, is_ptr, ret;
675 u32 tid;
676
677 if (!ctx->funcname && !(ctx->flags & TPARG_FL_TEVENT))
678 return -EINVAL;
679
680 is_ptr = split_next_field(varname, &field, ctx);
681 if (is_ptr < 0)
682 return is_ptr;
683 if (!is_ptr && field) {
684 /* dot-connected field on an argument is not supported. */
685 trace_probe_log_err(ctx->offset + field - varname,
686 NOSUP_DAT_ARG);
687 return -EOPNOTSUPP;
688 }
689
690 if (ctx->flags & TPARG_FL_TEVENT) {
691 ret = parse_trace_event(varname, code, ctx);
692 if (ret < 0) {
693 trace_probe_log_err(ctx->offset, BAD_ATTACH_ARG);
694 return ret;
695 }
696 /* TEVENT is only here via a typecast */
697 if (WARN_ON_ONCE(ctx->struct_btf == NULL))
698 return -EINVAL;
699 type = ctx->last_struct;
700 goto found_type;
701 }
702
703 if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
704 code->op = FETCH_OP_RETVAL;
705 /* Check whether the function return type is not void */
706 if (query_btf_context(ctx) == 0) {
707 if (ctx->proto->type == 0) {
708 trace_probe_log_err(ctx->offset, NO_RETVAL);
709 return -ENOENT;
710 }
711 tid = ctx->proto->type;
712 goto found;
713 }
714 if (field) {
715 trace_probe_log_err(ctx->offset + field - varname,
716 NO_BTF_ENTRY);
717 return -ENOENT;
718 }
719 return 0;
720 }
721
722 if (!ctx->btf) {
723 ret = query_btf_context(ctx);
724 if (ret < 0 || ctx->nr_params == 0) {
725 trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
726 return -ENOENT;
727 }
728 }
729 params = ctx->params;
730
731 for (i = 0; i < ctx->nr_params; i++) {
732 const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
733
734 if (name && !strcmp(name, varname)) {
735 if (tparg_is_function_entry(ctx->flags)) {
736 code->op = FETCH_OP_ARG;
737 if (ctx->flags & TPARG_FL_TPOINT)
738 code->param = i + 1;
739 else
740 code->param = i;
741 } else if (tparg_is_function_return(ctx->flags)) {
742 code->op = FETCH_OP_EDATA;
743 ret = __store_entry_arg(ctx->tp, i);
744 if (ret < 0) {
745 /* internal error */
746 return ret;
747 }
748 code->offset = ret;
749 }
750 tid = params[i].type;
751 goto found;
752 }
753 }
754 trace_probe_log_err(ctx->offset, NO_BTFARG);
755 return -ENOENT;
756
757 found:
758 type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
759 found_type:
760 if (!type) {
761 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
762 return -EINVAL;
763 }
764 /* Initialize the last type information */
765 ctx->last_type = type;
766 ctx->last_bitoffs = 0;
767 ctx->last_bitsize = 0;
768 if (field) {
769 ctx->offset += field - varname;
770 return parse_btf_field(field, type, pcode, end, ctx);
771 }
772 return 0;
773 }
774
find_fetch_type_from_btf_type(struct traceprobe_parse_context * ctx)775 static const struct fetch_type *find_fetch_type_from_btf_type(
776 struct traceprobe_parse_context *ctx)
777 {
778 struct btf *btf = ctx_btf(ctx);
779 const char *typestr = NULL;
780
781 if (btf && ctx->last_type)
782 typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
783
784 return find_fetch_type(typestr, ctx->flags);
785 }
786
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)787 static int parse_btf_bitfield(struct fetch_insn **pcode,
788 struct traceprobe_parse_context *ctx)
789 {
790 struct fetch_insn *code = *pcode;
791
792 if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
793 return 0;
794
795 code++;
796 if (code->op != FETCH_OP_NOP) {
797 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
798 return -EINVAL;
799 }
800 *pcode = code;
801
802 code->op = FETCH_OP_MOD_BF;
803 code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
804 code->rshift = 64 - ctx->last_bitsize;
805 code->basesize = 64 / 8;
806 return 0;
807 }
808
query_btf_struct(const char * sname,struct traceprobe_parse_context * ctx)809 static int query_btf_struct(const char *sname, struct traceprobe_parse_context *ctx)
810 {
811 struct btf *btf = NULL;
812 int id;
813
814 /* A struct_btf should only be used by a single argument */
815 if (WARN_ON_ONCE(ctx->struct_btf)) {
816 btf_put(ctx->struct_btf);
817 ctx->struct_btf = NULL;
818 }
819
820 id = bpf_find_btf_id(sname, BTF_KIND_STRUCT, &btf);
821 if (id < 0)
822 return id;
823 ctx->struct_btf = btf;
824 ctx->last_struct = btf_type_by_id(ctx->struct_btf, id);
825 return 0;
826 }
827
handle_typecast(char * arg,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)828 static int handle_typecast(char *arg, struct fetch_insn **pcode,
829 struct fetch_insn *end,
830 struct traceprobe_parse_context *ctx)
831 {
832 char *tmp;
833 int ret;
834
835 /* Currently this only works for eprobes */
836 if (!(ctx->flags & TPARG_FL_TEVENT)) {
837 trace_probe_log_err(ctx->offset, TYPECAST_NOT_EVENT);
838 return -EINVAL;
839 }
840
841 tmp = strchr(arg, ')');
842 if (!tmp) {
843 trace_probe_log_err(ctx->offset + strlen(arg),
844 DEREF_OPEN_BRACE);
845 return -EINVAL;
846 }
847 *tmp = '\0';
848 ret = query_btf_struct(arg + 1, ctx);
849 *tmp = ')';
850
851 if (ret < 0) {
852 trace_probe_log_err(ctx->offset + 1, NO_PTR_STRCT);
853 return -EINVAL;
854 }
855
856 tmp++;
857
858 ctx->offset += tmp - arg;
859 ret = parse_btf_arg(tmp, pcode, end, ctx);
860 return ret;
861 }
862
863 #else /* !CONFIG_PROBE_EVENTS_BTF_ARGS */
864
clear_struct_btf(struct traceprobe_parse_context * ctx)865 static void clear_struct_btf(struct traceprobe_parse_context *ctx)
866 {
867 ctx->struct_btf = NULL;
868 }
869
clear_btf_context(struct traceprobe_parse_context * ctx)870 static void clear_btf_context(struct traceprobe_parse_context *ctx)
871 {
872 ctx->btf = NULL;
873 }
874
query_btf_context(struct traceprobe_parse_context * ctx)875 static int query_btf_context(struct traceprobe_parse_context *ctx)
876 {
877 return -EOPNOTSUPP;
878 }
879
parse_btf_arg(char * varname,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)880 static int parse_btf_arg(char *varname,
881 struct fetch_insn **pcode, struct fetch_insn *end,
882 struct traceprobe_parse_context *ctx)
883 {
884 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
885 return -EOPNOTSUPP;
886 }
887
parse_btf_bitfield(struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)888 static int parse_btf_bitfield(struct fetch_insn **pcode,
889 struct traceprobe_parse_context *ctx)
890 {
891 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
892 return -EOPNOTSUPP;
893 }
894
895 #define find_fetch_type_from_btf_type(ctx) \
896 find_fetch_type(NULL, ctx->flags)
897
check_prepare_btf_string_fetch(char * typename,struct fetch_insn ** pcode,struct traceprobe_parse_context * ctx)898 static int check_prepare_btf_string_fetch(char *typename,
899 struct fetch_insn **pcode,
900 struct traceprobe_parse_context *ctx)
901 {
902 return 0;
903 }
904
handle_typecast(char * arg,struct fetch_insn ** pcode,struct fetch_insn * end,struct traceprobe_parse_context * ctx)905 static int handle_typecast(char *arg, struct fetch_insn **pcode,
906 struct fetch_insn *end,
907 struct traceprobe_parse_context *ctx)
908 {
909 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
910 return -EOPNOTSUPP;
911 }
912
913 #endif /* CONFIG_PROBE_EVENTS_BTF_ARGS */
914
915 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
916
store_entry_arg_at(struct fetch_insn * code,int argnum,int offset)917 static void store_entry_arg_at(struct fetch_insn *code, int argnum, int offset)
918 {
919 code[0].op = FETCH_OP_ARG;
920 code[0].param = argnum;
921 code[1].op = FETCH_OP_ST_EDATA;
922 code[1].offset = offset;
923 }
924
get_entry_arg_max_offset(struct probe_entry_arg * earg)925 static int get_entry_arg_max_offset(struct probe_entry_arg *earg)
926 {
927 int i, max_offset = 0;
928
929 /*
930 * earg->code[] array has an operation sequence which is run in
931 * the entry handler.
932 * The sequence stopped by FETCH_OP_END and each data stored in
933 * the entry data buffer by FETCH_OP_ST_EDATA. The FETCH_OP_ST_EDATA
934 * stores the data at the data buffer + its offset, and all data are
935 * "unsigned long" size. The offset must be increased when a data is
936 * stored. Thus we need to find the last FETCH_OP_ST_EDATA in the
937 * code array.
938 */
939 for (i = 0; i < earg->size - 1 && earg->code[i].op != FETCH_OP_END; i++) {
940 if (earg->code[i].op == FETCH_OP_ST_EDATA)
941 if (earg->code[i].offset > max_offset)
942 max_offset = earg->code[i].offset;
943 }
944 return max_offset;
945 }
946
947 /*
948 * Add the entry code to store the 'argnum'th parameter and return the offset
949 * in the entry data buffer where the data will be stored.
950 */
__store_entry_arg(struct trace_probe * tp,int argnum)951 static int __store_entry_arg(struct trace_probe *tp, int argnum)
952 {
953 struct probe_entry_arg *earg = tp->entry_arg;
954 int i, offset, last_offset = 0;
955
956 if (!earg) {
957 earg = kzalloc_flex(*earg, code, 2 * tp->nr_args + 1);
958 if (!earg)
959 return -ENOMEM;
960 earg->size = 2 * tp->nr_args + 1;
961 /* Fill the code buffer with 'end' to simplify it */
962 for (i = 0; i < earg->size; i++)
963 earg->code[i].op = FETCH_OP_END;
964 tp->entry_arg = earg;
965 store_entry_arg_at(earg->code, argnum, 0);
966 return 0;
967 }
968
969 /*
970 * NOTE: if anyone change the following rule, please rewrite this.
971 * The entry code array is filled with the pair of
972 *
973 * [FETCH_OP_ARG(argnum)]
974 * [FETCH_OP_ST_EDATA(offset of entry data buffer)]
975 *
976 * and the rest of entries are filled with [FETCH_OP_END].
977 * The offset should be incremented, thus the last pair should
978 * have the largest offset.
979 */
980
981 /* Search the offset for the sprcified argnum. */
982 for (i = 0; i < earg->size - 1 && earg->code[i].op != FETCH_OP_END; i += 2) {
983 if (WARN_ON_ONCE(earg->code[i].op != FETCH_OP_ARG))
984 return -EINVAL;
985
986 if (earg->code[i].param != argnum)
987 continue;
988
989 if (WARN_ON_ONCE(earg->code[i + 1].op != FETCH_OP_ST_EDATA))
990 return -EINVAL;
991
992 return earg->code[i + 1].offset;
993 }
994 /* Not found, append new entry if possible. */
995 if (i >= earg->size - 1)
996 return -ENOSPC;
997
998 /* The last entry must have the largest offset. */
999 if (i != 0) {
1000 if (WARN_ON_ONCE(earg->code[i - 1].op != FETCH_OP_ST_EDATA))
1001 return -EINVAL;
1002 last_offset = earg->code[i - 1].offset;
1003 }
1004
1005 offset = last_offset + sizeof(unsigned long);
1006 store_entry_arg_at(&earg->code[i], argnum, offset);
1007 return offset;
1008 }
1009
traceprobe_get_entry_data_size(struct trace_probe * tp)1010 int traceprobe_get_entry_data_size(struct trace_probe *tp)
1011 {
1012 struct probe_entry_arg *earg = tp->entry_arg;
1013
1014 if (!earg)
1015 return 0;
1016
1017 return get_entry_arg_max_offset(earg) + sizeof(unsigned long);
1018 }
1019
store_trace_entry_data(void * edata,struct trace_probe * tp,struct pt_regs * regs)1020 void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
1021 {
1022 struct probe_entry_arg *earg = tp->entry_arg;
1023 unsigned long val = 0;
1024 int i;
1025
1026 if (!earg)
1027 return;
1028
1029 for (i = 0; i < earg->size; i++) {
1030 struct fetch_insn *code = &earg->code[i];
1031
1032 switch (code->op) {
1033 case FETCH_OP_ARG:
1034 val = regs_get_kernel_argument(regs, code->param);
1035 break;
1036 case FETCH_OP_ST_EDATA:
1037 *(unsigned long *)((unsigned long)edata + code->offset) = val;
1038 break;
1039 case FETCH_OP_END:
1040 goto end;
1041 default:
1042 break;
1043 }
1044 }
1045 end:
1046 return;
1047 }
NOKPROBE_SYMBOL(store_trace_entry_data)1048 NOKPROBE_SYMBOL(store_trace_entry_data)
1049 #endif
1050
1051 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
1052
1053 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
1054 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
1055 struct fetch_insn **pcode,
1056 struct fetch_insn *end,
1057 struct traceprobe_parse_context *ctx)
1058 {
1059 struct fetch_insn *code = *pcode;
1060 int err = TP_ERR_BAD_VAR;
1061 char *arg = orig_arg + 1;
1062 unsigned long param;
1063 int ret = 0;
1064 int len;
1065
1066 if (ctx->flags & TPARG_FL_TEVENT) {
1067 if (parse_trace_event(arg, code, ctx) < 0) {
1068 /* 'comm' should be checked after field parsing. */
1069 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
1070 code->op = FETCH_OP_COMM;
1071 return 0;
1072 }
1073 goto inval;
1074 }
1075 return 0;
1076 }
1077
1078 if (str_has_prefix(arg, "retval")) {
1079 if (!(ctx->flags & TPARG_FL_RETURN)) {
1080 err = TP_ERR_RETVAL_ON_PROBE;
1081 goto inval;
1082 }
1083 if (!(ctx->flags & TPARG_FL_KERNEL) ||
1084 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1085 code->op = FETCH_OP_RETVAL;
1086 return 0;
1087 }
1088 return parse_btf_arg(orig_arg, pcode, end, ctx);
1089 }
1090
1091 len = str_has_prefix(arg, "stack");
1092 if (len) {
1093
1094 if (arg[len] == '\0') {
1095 code->op = FETCH_OP_STACKP;
1096 return 0;
1097 }
1098
1099 if (isdigit(arg[len])) {
1100 ret = kstrtoul(arg + len, 10, ¶m);
1101 if (ret)
1102 goto inval;
1103
1104 if ((ctx->flags & TPARG_FL_KERNEL) &&
1105 param > PARAM_MAX_STACK) {
1106 err = TP_ERR_BAD_STACK_NUM;
1107 goto inval;
1108 }
1109 code->op = FETCH_OP_STACK;
1110 code->param = (unsigned int)param;
1111 return 0;
1112 }
1113 goto inval;
1114 }
1115
1116 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
1117 code->op = FETCH_OP_COMM;
1118 return 0;
1119 }
1120
1121 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1122 len = str_has_prefix(arg, "arg");
1123 if (len) {
1124 ret = kstrtoul(arg + len, 10, ¶m);
1125 if (ret)
1126 goto inval;
1127
1128 if (!param || param > PARAM_MAX_STACK) {
1129 err = TP_ERR_BAD_ARG_NUM;
1130 goto inval;
1131 }
1132 param--; /* argN starts from 1, but internal arg[N] starts from 0 */
1133
1134 if (tparg_is_function_entry(ctx->flags)) {
1135 code->op = FETCH_OP_ARG;
1136 code->param = (unsigned int)param;
1137 /*
1138 * The tracepoint probe will probe a stub function, and the
1139 * first parameter of the stub is a dummy and should be ignored.
1140 */
1141 if (ctx->flags & TPARG_FL_TPOINT)
1142 code->param++;
1143 } else if (tparg_is_function_return(ctx->flags)) {
1144 /* function entry argument access from return probe */
1145 ret = __store_entry_arg(ctx->tp, param);
1146 if (ret < 0) /* This error should be an internal error */
1147 return ret;
1148
1149 code->op = FETCH_OP_EDATA;
1150 code->offset = ret;
1151 } else {
1152 err = TP_ERR_NOFENTRY_ARGS;
1153 goto inval;
1154 }
1155 return 0;
1156 }
1157 #endif
1158
1159 inval:
1160 __trace_probe_log_err(ctx->offset, err);
1161 return -EINVAL;
1162 }
1163
str_to_immediate(char * str,unsigned long * imm)1164 static int str_to_immediate(char *str, unsigned long *imm)
1165 {
1166 if (isdigit(str[0]))
1167 return kstrtoul(str, 0, imm);
1168 else if (str[0] == '-')
1169 return kstrtol(str, 0, (long *)imm);
1170 else if (str[0] == '+')
1171 return kstrtol(str + 1, 0, (long *)imm);
1172 return -EINVAL;
1173 }
1174
__parse_imm_string(char * str,char ** pbuf,int offs)1175 static int __parse_imm_string(char *str, char **pbuf, int offs)
1176 {
1177 size_t len = strlen(str);
1178
1179 if (!len || str[len - 1] != '"') {
1180 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1181 return -EINVAL;
1182 }
1183 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1184 if (!*pbuf)
1185 return -ENOMEM;
1186 return 0;
1187 }
1188
1189 /* Recursive argument parser */
1190 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)1191 parse_probe_arg(char *arg, const struct fetch_type *type,
1192 struct fetch_insn **pcode, struct fetch_insn *end,
1193 struct traceprobe_parse_context *ctx)
1194 {
1195 struct fetch_insn *code = *pcode;
1196 unsigned long param;
1197 int deref = FETCH_OP_DEREF;
1198 long offset = 0;
1199 char *tmp;
1200 int ret = 0;
1201
1202 switch (arg[0]) {
1203 case '$':
1204 ret = parse_probe_vars(arg, type, pcode, end, ctx);
1205 break;
1206
1207 case '%': /* named register */
1208 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1209 /* eprobe and fprobe do not handle registers */
1210 trace_probe_log_err(ctx->offset, BAD_VAR);
1211 break;
1212 }
1213 ret = regs_query_register_offset(arg + 1);
1214 if (ret >= 0) {
1215 code->op = FETCH_OP_REG;
1216 code->param = (unsigned int)ret;
1217 ret = 0;
1218 } else
1219 trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1220 break;
1221
1222 case '@': /* memory, file-offset or symbol */
1223 if (isdigit(arg[1])) {
1224 ret = kstrtoul(arg + 1, 0, ¶m);
1225 if (ret) {
1226 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1227 break;
1228 }
1229 /* load address */
1230 code->op = FETCH_OP_IMM;
1231 code->immediate = param;
1232 } else if (arg[1] == '+') {
1233 /* kprobes don't support file offsets */
1234 if (ctx->flags & TPARG_FL_KERNEL) {
1235 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1236 return -EINVAL;
1237 }
1238 ret = kstrtol(arg + 2, 0, &offset);
1239 if (ret) {
1240 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1241 break;
1242 }
1243
1244 code->op = FETCH_OP_FOFFS;
1245 code->immediate = (unsigned long)offset; // imm64?
1246 offset = 0;
1247 } else {
1248 /* uprobes don't support symbols */
1249 if (!(ctx->flags & TPARG_FL_KERNEL)) {
1250 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1251 return -EINVAL;
1252 }
1253 /* Preserve symbol for updating */
1254 code->op = FETCH_NOP_SYMBOL;
1255 code->data = kstrdup(arg + 1, GFP_KERNEL);
1256 if (!code->data)
1257 return -ENOMEM;
1258 if (++code == end) {
1259 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1260 return -EINVAL;
1261 }
1262 code->op = FETCH_OP_IMM;
1263 code->immediate = 0;
1264 }
1265 /* These are fetching from memory */
1266 if (++code == end) {
1267 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1268 return -EINVAL;
1269 }
1270 *pcode = code;
1271 code->op = FETCH_OP_DEREF;
1272 code->offset = offset;
1273 break;
1274
1275 case '+': /* deref memory */
1276 case '-':
1277 if (arg[1] == 'u') {
1278 deref = FETCH_OP_UDEREF;
1279 arg[1] = arg[0];
1280 arg++;
1281 }
1282 if (arg[0] == '+')
1283 arg++; /* Skip '+', because kstrtol() rejects it. */
1284 tmp = strchr(arg, '(');
1285 if (!tmp) {
1286 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1287 return -EINVAL;
1288 }
1289 *tmp = '\0';
1290 ret = kstrtol(arg, 0, &offset);
1291 if (ret) {
1292 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1293 break;
1294 }
1295 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1296 arg = tmp + 1;
1297 tmp = strrchr(arg, ')');
1298 if (!tmp) {
1299 trace_probe_log_err(ctx->offset + strlen(arg),
1300 DEREF_OPEN_BRACE);
1301 return -EINVAL;
1302 } else {
1303 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1304 int cur_offs = ctx->offset;
1305
1306 *tmp = '\0';
1307 ret = parse_probe_arg(arg, t2, &code, end, ctx);
1308 if (ret)
1309 break;
1310 ctx->offset = cur_offs;
1311 if (code->op == FETCH_OP_COMM ||
1312 code->op == FETCH_OP_DATA) {
1313 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1314 return -EINVAL;
1315 }
1316 if (++code == end) {
1317 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1318 return -EINVAL;
1319 }
1320 *pcode = code;
1321
1322 code->op = deref;
1323 code->offset = offset;
1324 /* Reset the last type if used */
1325 ctx->last_type = NULL;
1326 }
1327 break;
1328 case '\\': /* Immediate value */
1329 if (arg[1] == '"') { /* Immediate string */
1330 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1331 if (ret)
1332 break;
1333 code->op = FETCH_OP_DATA;
1334 code->data = tmp;
1335 } else {
1336 ret = str_to_immediate(arg + 1, &code->immediate);
1337 if (ret)
1338 trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1339 else
1340 code->op = FETCH_OP_IMM;
1341 }
1342 break;
1343 case '(':
1344 ret = handle_typecast(arg, pcode, end, ctx);
1345 break;
1346 default:
1347 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
1348 if (!tparg_is_function_entry(ctx->flags) &&
1349 !tparg_is_function_return(ctx->flags)) {
1350 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1351 return -EINVAL;
1352 }
1353 ret = parse_btf_arg(arg, pcode, end, ctx);
1354 break;
1355 }
1356 }
1357 if (!ret && code->op == FETCH_OP_NOP) {
1358 /* Parsed, but do not find fetch method */
1359 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1360 ret = -EINVAL;
1361 }
1362 return ret;
1363 }
1364
1365 /* 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)1366 static int __parse_bitfield_probe_arg(const char *bf,
1367 const struct fetch_type *t,
1368 struct fetch_insn **pcode)
1369 {
1370 struct fetch_insn *code = *pcode;
1371 unsigned long bw, bo;
1372 char *tail;
1373
1374 if (*bf != 'b')
1375 return 0;
1376
1377 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
1378
1379 if (bw == 0 || *tail != '@')
1380 return -EINVAL;
1381
1382 bf = tail + 1;
1383 bo = simple_strtoul(bf, &tail, 0);
1384
1385 if (tail == bf || *tail != '/')
1386 return -EINVAL;
1387 code++;
1388 if (code->op != FETCH_OP_NOP)
1389 return -EINVAL;
1390 *pcode = code;
1391
1392 code->op = FETCH_OP_MOD_BF;
1393 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1394 code->rshift = BYTES_TO_BITS(t->size) - bw;
1395 code->basesize = t->size;
1396
1397 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1398 }
1399
1400 /* Split type part from @arg and return it. */
parse_probe_arg_type(char * arg,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1401 static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
1402 struct traceprobe_parse_context *ctx)
1403 {
1404 char *t = NULL, *t2, *t3;
1405 int offs;
1406
1407 t = strchr(arg, ':');
1408 if (t) {
1409 *t++ = '\0';
1410 t2 = strchr(t, '[');
1411 if (t2) {
1412 *t2++ = '\0';
1413 t3 = strchr(t2, ']');
1414 if (!t3) {
1415 offs = t2 + strlen(t2) - arg;
1416
1417 trace_probe_log_err(ctx->offset + offs,
1418 ARRAY_NO_CLOSE);
1419 return ERR_PTR(-EINVAL);
1420 } else if (t3[1] != '\0') {
1421 trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1422 BAD_ARRAY_SUFFIX);
1423 return ERR_PTR(-EINVAL);
1424 }
1425 *t3 = '\0';
1426 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1427 trace_probe_log_err(ctx->offset + t2 - arg,
1428 BAD_ARRAY_NUM);
1429 return ERR_PTR(-EINVAL);
1430 }
1431 if (parg->count > MAX_ARRAY_LEN) {
1432 trace_probe_log_err(ctx->offset + t2 - arg,
1433 ARRAY_TOO_BIG);
1434 return ERR_PTR(-EINVAL);
1435 }
1436 }
1437 }
1438 offs = t ? t - arg : 0;
1439
1440 /*
1441 * Since $comm and immediate string can not be dereferenced,
1442 * we can find those by strcmp. But ignore for eprobes.
1443 */
1444 if (!(ctx->flags & TPARG_FL_TEVENT) &&
1445 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1446 strncmp(arg, "\\\"", 2) == 0)) {
1447 /* The type of $comm must be "string", and not an array type. */
1448 if (parg->count || (t && strcmp(t, "string"))) {
1449 trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
1450 return ERR_PTR(-EINVAL);
1451 }
1452 parg->type = find_fetch_type("string", ctx->flags);
1453 } else
1454 parg->type = find_fetch_type(t, ctx->flags);
1455
1456 if (!parg->type) {
1457 trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
1458 return ERR_PTR(-EINVAL);
1459 }
1460
1461 return t;
1462 }
1463
1464 /* 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)1465 static int finalize_fetch_insn(struct fetch_insn *code,
1466 struct probe_arg *parg,
1467 char *type,
1468 int type_offset,
1469 struct traceprobe_parse_context *ctx)
1470 {
1471 struct fetch_insn *scode;
1472 int ret;
1473
1474 /* Store operation */
1475 if (parg->type->is_string) {
1476 /* Check bad combination of the type and the last fetch_insn. */
1477 if (!strcmp(parg->type->name, "symstr")) {
1478 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1479 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1480 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1481 trace_probe_log_err(ctx->offset + type_offset,
1482 BAD_SYMSTRING);
1483 return -EINVAL;
1484 }
1485 } else {
1486 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1487 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1488 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1489 trace_probe_log_err(ctx->offset + type_offset,
1490 BAD_STRING);
1491 return -EINVAL;
1492 }
1493 }
1494
1495 if (!strcmp(parg->type->name, "symstr") ||
1496 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1497 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1498 parg->count) {
1499 /*
1500 * IMM, DATA and COMM is pointing actual address, those
1501 * must be kept, and if parg->count != 0, this is an
1502 * array of string pointers instead of string address
1503 * itself.
1504 * For the symstr, it doesn't need to dereference, thus
1505 * it just get the value.
1506 */
1507 code++;
1508 if (code->op != FETCH_OP_NOP) {
1509 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1510 return -EINVAL;
1511 }
1512 }
1513
1514 /* If op == DEREF, replace it with STRING */
1515 if (!strcmp(parg->type->name, "ustring") ||
1516 code->op == FETCH_OP_UDEREF)
1517 code->op = FETCH_OP_ST_USTRING;
1518 else if (!strcmp(parg->type->name, "symstr"))
1519 code->op = FETCH_OP_ST_SYMSTR;
1520 else
1521 code->op = FETCH_OP_ST_STRING;
1522 code->size = parg->type->size;
1523 parg->dynamic = true;
1524 } else if (code->op == FETCH_OP_DEREF) {
1525 code->op = FETCH_OP_ST_MEM;
1526 code->size = parg->type->size;
1527 } else if (code->op == FETCH_OP_UDEREF) {
1528 code->op = FETCH_OP_ST_UMEM;
1529 code->size = parg->type->size;
1530 } else {
1531 code++;
1532 if (code->op != FETCH_OP_NOP) {
1533 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1534 return -E2BIG;
1535 }
1536 code->op = FETCH_OP_ST_RAW;
1537 code->size = parg->type->size;
1538 }
1539
1540 /* Save storing fetch_insn. */
1541 scode = code;
1542
1543 /* Modify operation */
1544 if (type != NULL) {
1545 /* Bitfield needs a special fetch_insn. */
1546 ret = __parse_bitfield_probe_arg(type, parg->type, &code);
1547 if (ret) {
1548 trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
1549 return ret;
1550 }
1551 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1552 ctx->last_type) {
1553 /* If user not specified the type, try parsing BTF bitfield. */
1554 ret = parse_btf_bitfield(&code, ctx);
1555 if (ret)
1556 return ret;
1557 }
1558
1559 /* Loop(Array) operation */
1560 if (parg->count) {
1561 if (scode->op != FETCH_OP_ST_MEM &&
1562 scode->op != FETCH_OP_ST_STRING &&
1563 scode->op != FETCH_OP_ST_USTRING) {
1564 trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
1565 return -EINVAL;
1566 }
1567 code++;
1568 if (code->op != FETCH_OP_NOP) {
1569 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1570 return -E2BIG;
1571 }
1572 code->op = FETCH_OP_LP_ARRAY;
1573 code->param = parg->count;
1574 }
1575
1576 /* Finalize the fetch_insn array. */
1577 code++;
1578 code->op = FETCH_OP_END;
1579
1580 return 0;
1581 }
1582
1583 /* String length checking wrapper */
traceprobe_parse_probe_arg_body(const char * argv,ssize_t * size,struct probe_arg * parg,struct traceprobe_parse_context * ctx)1584 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1585 struct probe_arg *parg,
1586 struct traceprobe_parse_context *ctx)
1587 {
1588 struct fetch_insn *code, *tmp = NULL;
1589 char *type, *arg __free(kfree) = NULL;
1590 int ret, len;
1591
1592 len = strlen(argv);
1593 if (len > MAX_ARGSTR_LEN) {
1594 trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1595 return -E2BIG;
1596 } else if (len == 0) {
1597 trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1598 return -EINVAL;
1599 }
1600
1601 arg = kstrdup(argv, GFP_KERNEL);
1602 if (!arg)
1603 return -ENOMEM;
1604
1605 parg->comm = kstrdup(arg, GFP_KERNEL);
1606 if (!parg->comm)
1607 return -ENOMEM;
1608
1609 type = parse_probe_arg_type(arg, parg, ctx);
1610 if (IS_ERR(type))
1611 return PTR_ERR(type);
1612
1613 code = tmp = kzalloc_objs(*code, FETCH_INSN_MAX);
1614 if (!code)
1615 return -ENOMEM;
1616 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1617
1618 ctx->last_type = NULL;
1619 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1620 ctx);
1621 if (ret < 0)
1622 goto fail;
1623
1624 /* Update storing type if BTF is available */
1625 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1626 ctx->last_type) {
1627 if (!type) {
1628 parg->type = find_fetch_type_from_btf_type(ctx);
1629 } else if (strstr(type, "string")) {
1630 ret = check_prepare_btf_string_fetch(type, &code, ctx);
1631 if (ret)
1632 goto fail;
1633 }
1634 }
1635 parg->offset = *size;
1636 *size += parg->type->size * (parg->count ?: 1);
1637
1638 if (*size > MAX_PROBE_EVENT_SIZE) {
1639 ret = -E2BIG;
1640 trace_probe_log_err(ctx->offset, EVENT_TOO_BIG);
1641 goto fail;
1642 }
1643
1644 if (parg->count) {
1645 len = strlen(parg->type->fmttype) + 6;
1646 parg->fmt = kmalloc(len, GFP_KERNEL);
1647 if (!parg->fmt) {
1648 ret = -ENOMEM;
1649 goto fail;
1650 }
1651 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1652 parg->count);
1653 }
1654
1655 ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
1656 if (ret < 0)
1657 goto fail;
1658
1659 for (; code < tmp + FETCH_INSN_MAX; code++)
1660 if (code->op == FETCH_OP_END)
1661 break;
1662 /* Shrink down the code buffer */
1663 parg->code = kzalloc_objs(*code, code - tmp + 1);
1664 if (!parg->code)
1665 ret = -ENOMEM;
1666 else
1667 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1668
1669 fail:
1670 if (ret < 0) {
1671 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1672 if (code->op == FETCH_NOP_SYMBOL ||
1673 code->op == FETCH_OP_DATA)
1674 kfree(code->data);
1675 }
1676 kfree(tmp);
1677
1678 /* struct_btf should not be passed to other arguments */
1679 clear_struct_btf(ctx);
1680
1681 return ret;
1682 }
1683
1684 /* 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)1685 static int traceprobe_conflict_field_name(const char *name,
1686 struct probe_arg *args, int narg)
1687 {
1688 int i;
1689
1690 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1691 if (strcmp(reserved_field_names[i], name) == 0)
1692 return 1;
1693
1694 for (i = 0; i < narg; i++)
1695 if (strcmp(args[i].name, name) == 0)
1696 return 1;
1697
1698 return 0;
1699 }
1700
generate_probe_arg_name(const char * arg,int idx)1701 static char *generate_probe_arg_name(const char *arg, int idx)
1702 {
1703 char *name = NULL;
1704 const char *end;
1705
1706 /*
1707 * If argument name is omitted, try arg as a name (BTF variable)
1708 * or "argN".
1709 */
1710 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1711 end = strchr(arg, ':');
1712 if (!end)
1713 end = arg + strlen(arg);
1714
1715 name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1716 if (!name || !is_good_name(name)) {
1717 kfree(name);
1718 name = NULL;
1719 }
1720 }
1721
1722 if (!name)
1723 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1724
1725 return name;
1726 }
1727
traceprobe_parse_probe_arg(struct trace_probe * tp,int i,const char * arg,struct traceprobe_parse_context * ctx)1728 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1729 struct traceprobe_parse_context *ctx)
1730 {
1731 struct probe_arg *parg = &tp->args[i];
1732 const char *body;
1733
1734 ctx->tp = tp;
1735 body = strchr(arg, '=');
1736 if (body) {
1737 if (body - arg > MAX_ARG_NAME_LEN) {
1738 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1739 return -EINVAL;
1740 } else if (body == arg) {
1741 trace_probe_log_err(0, NO_ARG_NAME);
1742 return -EINVAL;
1743 }
1744 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1745 body++;
1746 } else {
1747 parg->name = generate_probe_arg_name(arg, i);
1748 body = arg;
1749 }
1750 if (!parg->name)
1751 return -ENOMEM;
1752
1753 if (!is_good_name(parg->name)) {
1754 trace_probe_log_err(0, BAD_ARG_NAME);
1755 return -EINVAL;
1756 }
1757 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1758 trace_probe_log_err(0, USED_ARG_NAME);
1759 return -EINVAL;
1760 }
1761 ctx->offset = body - arg;
1762 /* Parse fetch argument */
1763 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1764 }
1765
traceprobe_free_probe_arg(struct probe_arg * arg)1766 void traceprobe_free_probe_arg(struct probe_arg *arg)
1767 {
1768 struct fetch_insn *code = arg->code;
1769
1770 while (code && code->op != FETCH_OP_END) {
1771 if (code->op == FETCH_NOP_SYMBOL ||
1772 code->op == FETCH_OP_DATA)
1773 kfree(code->data);
1774 code++;
1775 }
1776 kfree(arg->code);
1777 kfree(arg->name);
1778 kfree(arg->comm);
1779 kfree(arg->fmt);
1780 }
1781
argv_has_var_arg(int argc,const char * argv[],int * args_idx,struct traceprobe_parse_context * ctx)1782 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1783 struct traceprobe_parse_context *ctx)
1784 {
1785 int i, found = 0;
1786
1787 for (i = 0; i < argc; i++)
1788 if (str_has_prefix(argv[i], "$arg")) {
1789 trace_probe_log_set_index(i + 2);
1790
1791 if (!tparg_is_function_entry(ctx->flags) &&
1792 !tparg_is_function_return(ctx->flags)) {
1793 trace_probe_log_err(0, NOFENTRY_ARGS);
1794 return -EINVAL;
1795 }
1796
1797 if (isdigit(argv[i][4])) {
1798 found = 1;
1799 continue;
1800 }
1801
1802 if (argv[i][4] != '*') {
1803 trace_probe_log_err(0, BAD_VAR);
1804 return -EINVAL;
1805 }
1806
1807 if (*args_idx >= 0 && *args_idx < argc) {
1808 trace_probe_log_err(0, DOUBLE_ARGS);
1809 return -EINVAL;
1810 }
1811 found = 1;
1812 *args_idx = i;
1813 }
1814
1815 return found;
1816 }
1817
sprint_nth_btf_arg(int idx,const char * type,char * buf,int bufsize,struct traceprobe_parse_context * ctx)1818 static int sprint_nth_btf_arg(int idx, const char *type,
1819 char *buf, int bufsize,
1820 struct traceprobe_parse_context *ctx)
1821 {
1822 const char *name;
1823 int ret;
1824
1825 if (idx >= ctx->nr_params) {
1826 trace_probe_log_err(0, NO_BTFARG);
1827 return -ENOENT;
1828 }
1829 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1830 if (!name) {
1831 trace_probe_log_err(0, NO_BTF_ENTRY);
1832 return -ENOENT;
1833 }
1834 ret = snprintf(buf, bufsize, "%s%s", name, type);
1835 if (ret >= bufsize) {
1836 trace_probe_log_err(0, ARGS_2LONG);
1837 return -E2BIG;
1838 }
1839 return ret;
1840 }
1841
1842 /* 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)1843 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1844 int *new_argc, char *buf, int bufsize,
1845 struct traceprobe_parse_context *ctx)
1846 {
1847 const struct btf_param *params = NULL;
1848 int i, j, n, used, ret, args_idx = -1;
1849 const char **new_argv __free(kfree) = NULL;
1850
1851 ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1852 if (ret < 0)
1853 return ERR_PTR(ret);
1854
1855 if (!ret) {
1856 *new_argc = argc;
1857 return NULL;
1858 }
1859
1860 ret = query_btf_context(ctx);
1861 if (ret < 0 || ctx->nr_params == 0) {
1862 if (args_idx != -1) {
1863 /* $arg* requires BTF info */
1864 trace_probe_log_err(0, NOSUP_BTFARG);
1865 return (const char **)params;
1866 }
1867 *new_argc = argc;
1868 return NULL;
1869 }
1870
1871 if (args_idx >= 0)
1872 *new_argc = argc + ctx->nr_params - 1;
1873 else
1874 *new_argc = argc;
1875
1876 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1877 if (!new_argv)
1878 return ERR_PTR(-ENOMEM);
1879
1880 used = 0;
1881 for (i = 0, j = 0; i < argc; i++) {
1882 trace_probe_log_set_index(i + 2);
1883 if (i == args_idx) {
1884 for (n = 0; n < ctx->nr_params; n++) {
1885 ret = sprint_nth_btf_arg(n, "", buf + used,
1886 bufsize - used, ctx);
1887 if (ret < 0)
1888 return ERR_PTR(ret);
1889
1890 new_argv[j++] = buf + used;
1891 used += ret + 1;
1892 }
1893 continue;
1894 }
1895
1896 if (str_has_prefix(argv[i], "$arg")) {
1897 char *type = NULL;
1898
1899 n = simple_strtoul(argv[i] + 4, &type, 10);
1900 if (type && !(*type == ':' || *type == '\0')) {
1901 trace_probe_log_err(0, BAD_VAR);
1902 return ERR_PTR(-ENOENT);
1903 }
1904 /* Note: $argN starts from $arg1 */
1905 ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1906 bufsize - used, ctx);
1907 if (ret < 0)
1908 return ERR_PTR(ret);
1909 new_argv[j++] = buf + used;
1910 used += ret + 1;
1911 } else
1912 new_argv[j++] = argv[i];
1913 }
1914
1915 return_ptr(new_argv);
1916 }
1917
1918 /* @buf: *buf must be equal to NULL. Caller must to free *buf */
traceprobe_expand_dentry_args(int argc,const char * argv[],char ** buf)1919 int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
1920 {
1921 int i, used, ret;
1922 const int bufsize = MAX_DENTRY_ARGS_LEN;
1923 char *tmpbuf __free(kfree) = NULL;
1924
1925 if (*buf)
1926 return -EINVAL;
1927
1928 used = 0;
1929 for (i = 0; i < argc; i++) {
1930 char *tmp __free(kfree) = NULL;
1931 char *equal;
1932 size_t arg_len;
1933
1934 if (!glob_match("*:%p[dD]", argv[i]))
1935 continue;
1936
1937 if (!tmpbuf) {
1938 tmpbuf = kmalloc(bufsize, GFP_KERNEL);
1939 if (!tmpbuf)
1940 return -ENOMEM;
1941 }
1942
1943 tmp = kstrdup(argv[i], GFP_KERNEL);
1944 if (!tmp)
1945 return -ENOMEM;
1946
1947 equal = strchr(tmp, '=');
1948 if (equal)
1949 *equal = '\0';
1950 arg_len = strlen(argv[i]);
1951 tmp[arg_len - 4] = '\0';
1952 if (argv[i][arg_len - 1] == 'd')
1953 ret = snprintf(tmpbuf + used, bufsize - used,
1954 "%s%s+0x0(+0x%zx(%s)):string",
1955 equal ? tmp : "", equal ? "=" : "",
1956 offsetof(struct dentry, d_name.name),
1957 equal ? equal + 1 : tmp);
1958 else
1959 ret = snprintf(tmpbuf + used, bufsize - used,
1960 "%s%s+0x0(+0x%zx(+0x%zx(%s))):string",
1961 equal ? tmp : "", equal ? "=" : "",
1962 offsetof(struct dentry, d_name.name),
1963 offsetof(struct file, f_path.dentry),
1964 equal ? equal + 1 : tmp);
1965
1966 if (ret >= bufsize - used)
1967 return -ENOMEM;
1968 argv[i] = tmpbuf + used;
1969 used += ret + 1;
1970 }
1971
1972 *buf = no_free_ptr(tmpbuf);
1973 return 0;
1974 }
1975
traceprobe_finish_parse(struct traceprobe_parse_context * ctx)1976 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1977 {
1978 clear_btf_context(ctx);
1979 }
1980
traceprobe_update_arg(struct probe_arg * arg)1981 int traceprobe_update_arg(struct probe_arg *arg)
1982 {
1983 struct fetch_insn *code = arg->code;
1984 long offset;
1985 char *tmp;
1986 char c;
1987 int ret = 0;
1988
1989 while (code && code->op != FETCH_OP_END) {
1990 if (code->op == FETCH_NOP_SYMBOL) {
1991 if (code[1].op != FETCH_OP_IMM)
1992 return -EINVAL;
1993
1994 tmp = strpbrk(code->data, "+-");
1995 if (tmp)
1996 c = *tmp;
1997 ret = traceprobe_split_symbol_offset(code->data,
1998 &offset);
1999 if (ret)
2000 return ret;
2001
2002 code[1].immediate =
2003 (unsigned long)kallsyms_lookup_name(code->data);
2004 if (tmp)
2005 *tmp = c;
2006 if (!code[1].immediate)
2007 return -ENOENT;
2008 code[1].immediate += offset;
2009 }
2010 code++;
2011 }
2012 return 0;
2013 }
2014
2015 /* When len=0, we just calculate the needed length */
2016 #define LEN_OR_ZERO (len ? len - pos : 0)
__set_print_fmt(struct trace_probe * tp,char * buf,int len,enum probe_print_type ptype)2017 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
2018 enum probe_print_type ptype)
2019 {
2020 struct probe_arg *parg;
2021 int i, j;
2022 int pos = 0;
2023 const char *fmt, *arg;
2024
2025 switch (ptype) {
2026 case PROBE_PRINT_NORMAL:
2027 fmt = "(%lx)";
2028 arg = ", REC->" FIELD_STRING_IP;
2029 break;
2030 case PROBE_PRINT_RETURN:
2031 fmt = "(%lx <- %lx)";
2032 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
2033 break;
2034 case PROBE_PRINT_EVENT:
2035 fmt = "";
2036 arg = "";
2037 break;
2038 default:
2039 WARN_ON_ONCE(1);
2040 return 0;
2041 }
2042
2043 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
2044
2045 for (i = 0; i < tp->nr_args; i++) {
2046 parg = tp->args + i;
2047 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
2048 if (parg->count) {
2049 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
2050 parg->type->fmt);
2051 for (j = 1; j < parg->count; j++)
2052 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
2053 parg->type->fmt);
2054 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
2055 } else
2056 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
2057 parg->type->fmt);
2058 }
2059
2060 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
2061
2062 for (i = 0; i < tp->nr_args; i++) {
2063 parg = tp->args + i;
2064 if (parg->count) {
2065 if (parg->type->is_string)
2066 fmt = ", __get_str(%s[%d])";
2067 else
2068 fmt = ", REC->%s[%d]";
2069 for (j = 0; j < parg->count; j++)
2070 pos += snprintf(buf + pos, LEN_OR_ZERO,
2071 fmt, parg->name, j);
2072 } else {
2073 if (parg->type->is_string)
2074 fmt = ", __get_str(%s)";
2075 else
2076 fmt = ", REC->%s";
2077 pos += snprintf(buf + pos, LEN_OR_ZERO,
2078 fmt, parg->name);
2079 }
2080 }
2081
2082 /* return the length of print_fmt */
2083 return pos;
2084 }
2085 #undef LEN_OR_ZERO
2086
traceprobe_set_print_fmt(struct trace_probe * tp,enum probe_print_type ptype)2087 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
2088 {
2089 struct trace_event_call *call = trace_probe_event_call(tp);
2090 int len;
2091 char *print_fmt;
2092
2093 /* First: called with 0 length to calculate the needed length */
2094 len = __set_print_fmt(tp, NULL, 0, ptype);
2095 print_fmt = kmalloc(len + 1, GFP_KERNEL);
2096 if (!print_fmt)
2097 return -ENOMEM;
2098
2099 /* Second: actually write the @print_fmt */
2100 __set_print_fmt(tp, print_fmt, len + 1, ptype);
2101 call->print_fmt = print_fmt;
2102
2103 return 0;
2104 }
2105
traceprobe_define_arg_fields(struct trace_event_call * event_call,size_t offset,struct trace_probe * tp)2106 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
2107 size_t offset, struct trace_probe *tp)
2108 {
2109 int ret, i;
2110
2111 /* Set argument names as fields */
2112 for (i = 0; i < tp->nr_args; i++) {
2113 struct probe_arg *parg = &tp->args[i];
2114 const char *fmt = parg->type->fmttype;
2115 int size = parg->type->size;
2116
2117 if (parg->fmt)
2118 fmt = parg->fmt;
2119 if (parg->count)
2120 size *= parg->count;
2121 ret = trace_define_field(event_call, fmt, parg->name,
2122 offset + parg->offset, size,
2123 parg->type->is_signed,
2124 FILTER_OTHER);
2125 if (ret)
2126 return ret;
2127 }
2128 return 0;
2129 }
2130
trace_probe_event_free(struct trace_probe_event * tpe)2131 static void trace_probe_event_free(struct trace_probe_event *tpe)
2132 {
2133 kfree(tpe->class.system);
2134 kfree(tpe->call.name);
2135 kfree(tpe->call.print_fmt);
2136 kfree(tpe);
2137 }
2138
trace_probe_append(struct trace_probe * tp,struct trace_probe * to)2139 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
2140 {
2141 if (trace_probe_has_sibling(tp))
2142 return -EBUSY;
2143
2144 list_del_init(&tp->list);
2145 trace_probe_event_free(tp->event);
2146
2147 tp->event = to->event;
2148 list_add_tail(&tp->list, trace_probe_probe_list(to));
2149
2150 return 0;
2151 }
2152
trace_probe_unlink(struct trace_probe * tp)2153 void trace_probe_unlink(struct trace_probe *tp)
2154 {
2155 list_del_init(&tp->list);
2156 if (list_empty(trace_probe_probe_list(tp)))
2157 trace_probe_event_free(tp->event);
2158 tp->event = NULL;
2159 }
2160
trace_probe_cleanup(struct trace_probe * tp)2161 void trace_probe_cleanup(struct trace_probe *tp)
2162 {
2163 int i;
2164
2165 for (i = 0; i < tp->nr_args; i++)
2166 traceprobe_free_probe_arg(&tp->args[i]);
2167
2168 if (tp->entry_arg) {
2169 kfree(tp->entry_arg);
2170 tp->entry_arg = NULL;
2171 }
2172
2173 if (tp->event)
2174 trace_probe_unlink(tp);
2175 }
2176
trace_probe_init(struct trace_probe * tp,const char * event,const char * group,bool alloc_filter,int nargs)2177 int trace_probe_init(struct trace_probe *tp, const char *event,
2178 const char *group, bool alloc_filter, int nargs)
2179 {
2180 struct trace_event_call *call;
2181 size_t size = sizeof(struct trace_probe_event);
2182 int ret = 0;
2183
2184 if (!event || !group)
2185 return -EINVAL;
2186
2187 if (alloc_filter)
2188 size += sizeof(struct trace_uprobe_filter);
2189
2190 tp->event = kzalloc(size, GFP_KERNEL);
2191 if (!tp->event)
2192 return -ENOMEM;
2193
2194 INIT_LIST_HEAD(&tp->event->files);
2195 INIT_LIST_HEAD(&tp->event->class.fields);
2196 INIT_LIST_HEAD(&tp->event->probes);
2197 INIT_LIST_HEAD(&tp->list);
2198 list_add(&tp->list, &tp->event->probes);
2199
2200 call = trace_probe_event_call(tp);
2201 call->class = &tp->event->class;
2202 call->name = kstrdup(event, GFP_KERNEL);
2203 if (!call->name) {
2204 ret = -ENOMEM;
2205 goto error;
2206 }
2207
2208 tp->event->class.system = kstrdup(group, GFP_KERNEL);
2209 if (!tp->event->class.system) {
2210 ret = -ENOMEM;
2211 goto error;
2212 }
2213
2214 tp->nr_args = nargs;
2215 /* Make sure pointers in args[] are NULL */
2216 if (nargs)
2217 memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
2218
2219 return 0;
2220
2221 error:
2222 trace_probe_cleanup(tp);
2223 return ret;
2224 }
2225
2226 static struct trace_event_call *
find_trace_event_call(const char * system,const char * event_name)2227 find_trace_event_call(const char *system, const char *event_name)
2228 {
2229 struct trace_event_call *tp_event;
2230 const char *name;
2231
2232 list_for_each_entry(tp_event, &ftrace_events, list) {
2233 if (!tp_event->class->system ||
2234 strcmp(system, tp_event->class->system))
2235 continue;
2236 name = trace_event_name(tp_event);
2237 if (!name || strcmp(event_name, name))
2238 continue;
2239 return tp_event;
2240 }
2241
2242 return NULL;
2243 }
2244
trace_probe_register_event_call(struct trace_probe * tp)2245 int trace_probe_register_event_call(struct trace_probe *tp)
2246 {
2247 struct trace_event_call *call = trace_probe_event_call(tp);
2248 int ret;
2249
2250 lockdep_assert_held(&event_mutex);
2251
2252 if (find_trace_event_call(trace_probe_group_name(tp),
2253 trace_probe_name(tp)))
2254 return -EEXIST;
2255
2256 ret = register_trace_event(&call->event);
2257 if (!ret)
2258 return -ENODEV;
2259
2260 ret = trace_add_event_call(call);
2261 if (ret)
2262 unregister_trace_event(&call->event);
2263
2264 return ret;
2265 }
2266
trace_probe_add_file(struct trace_probe * tp,struct trace_event_file * file)2267 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2268 {
2269 struct event_file_link *link;
2270
2271 link = kmalloc_obj(*link);
2272 if (!link)
2273 return -ENOMEM;
2274
2275 link->file = file;
2276 INIT_LIST_HEAD(&link->list);
2277 list_add_tail_rcu(&link->list, &tp->event->files);
2278 trace_probe_set_flag(tp, TP_FLAG_TRACE);
2279 return 0;
2280 }
2281
trace_probe_get_file_link(struct trace_probe * tp,struct trace_event_file * file)2282 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2283 struct trace_event_file *file)
2284 {
2285 struct event_file_link *link;
2286
2287 trace_probe_for_each_link(link, tp) {
2288 if (link->file == file)
2289 return link;
2290 }
2291
2292 return NULL;
2293 }
2294
trace_probe_remove_file(struct trace_probe * tp,struct trace_event_file * file)2295 int trace_probe_remove_file(struct trace_probe *tp,
2296 struct trace_event_file *file)
2297 {
2298 struct event_file_link *link;
2299
2300 link = trace_probe_get_file_link(tp, file);
2301 if (!link)
2302 return -ENOENT;
2303
2304 list_del_rcu(&link->list);
2305 kvfree_rcu_mightsleep(link);
2306
2307 if (list_empty(&tp->event->files))
2308 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2309
2310 return 0;
2311 }
2312
2313 /*
2314 * Return the smallest index of different type argument (start from 1).
2315 * If all argument types and name are same, return 0.
2316 */
trace_probe_compare_arg_type(struct trace_probe * a,struct trace_probe * b)2317 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2318 {
2319 int i;
2320
2321 /* In case of more arguments */
2322 if (a->nr_args < b->nr_args)
2323 return a->nr_args + 1;
2324 if (a->nr_args > b->nr_args)
2325 return b->nr_args + 1;
2326
2327 for (i = 0; i < a->nr_args; i++) {
2328 if ((b->nr_args <= i) ||
2329 ((a->args[i].type != b->args[i].type) ||
2330 (a->args[i].count != b->args[i].count) ||
2331 strcmp(a->args[i].name, b->args[i].name)))
2332 return i + 1;
2333 }
2334
2335 return 0;
2336 }
2337
trace_probe_match_command_args(struct trace_probe * tp,int argc,const char ** argv)2338 bool trace_probe_match_command_args(struct trace_probe *tp,
2339 int argc, const char **argv)
2340 {
2341 char buf[MAX_ARGSTR_LEN + 1];
2342 int i;
2343
2344 if (tp->nr_args < argc)
2345 return false;
2346
2347 for (i = 0; i < argc; i++) {
2348 snprintf(buf, sizeof(buf), "%s=%s",
2349 tp->args[i].name, tp->args[i].comm);
2350 if (strcmp(buf, argv[i]))
2351 return false;
2352 }
2353 return true;
2354 }
2355
trace_probe_create(const char * raw_command,int (* createfn)(int,const char **))2356 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2357 {
2358 int argc = 0, ret = 0;
2359 char **argv;
2360
2361 argv = argv_split(GFP_KERNEL, raw_command, &argc);
2362 if (!argv)
2363 return -ENOMEM;
2364
2365 if (argc)
2366 ret = createfn(argc, (const char **)argv);
2367
2368 argv_free(argv);
2369
2370 return ret;
2371 }
2372
trace_probe_print_args(struct trace_seq * s,struct probe_arg * args,int nr_args,u8 * data,void * field)2373 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2374 u8 *data, void *field)
2375 {
2376 void *p;
2377 int i, j;
2378
2379 for (i = 0; i < nr_args; i++) {
2380 struct probe_arg *a = args + i;
2381
2382 trace_seq_printf(s, " %s=", a->name);
2383 if (likely(!a->count)) {
2384 if (!a->type->print(s, data + a->offset, field))
2385 return -ENOMEM;
2386 continue;
2387 }
2388 trace_seq_putc(s, '{');
2389 p = data + a->offset;
2390 for (j = 0; j < a->count; j++) {
2391 if (!a->type->print(s, p, field))
2392 return -ENOMEM;
2393 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2394 p += a->type->size;
2395 }
2396 }
2397 return 0;
2398 }
2399