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