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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / tools / perf / util / probe-finder.c
blobc470c49a804fd3c1539cd6cf3f87964db79ed131
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * probe-finder.c : C expression to kprobe event converter
4 *
5 * Written by Masami Hiramatsu <mhiramat@redhat.com>
6 */
7
8 #include <inttypes.h>
9 #include <sys/utsname.h>
10 #include <sys/types.h>
11 #include <sys/stat.h>
12 #include <fcntl.h>
13 #include <errno.h>
14 #include <stdio.h>
15 #include <unistd.h>
16 #include <stdlib.h>
17 #include <string.h>
18 #include <stdarg.h>
19 #include <dwarf-regs.h>
20
21 #include <linux/bitops.h>
22 #include <linux/zalloc.h>
23 #include "event.h"
24 #include "dso.h"
25 #include "debug.h"
26 #include "intlist.h"
27 #include "strbuf.h"
28 #include "strlist.h"
29 #include "symbol.h"
30 #include "probe-finder.h"
31 #include "probe-file.h"
32 #include "string2.h"
33
34 /* Kprobe tracer basic type is up to u64 */
35 #define MAX_BASIC_TYPE_BITS 64
36
37 /* Dwarf FL wrappers */
38 static char *debuginfo_path; /* Currently dummy */
39
40 static const Dwfl_Callbacks offline_callbacks = {
41 .find_debuginfo = dwfl_standard_find_debuginfo,
42 .debuginfo_path = &debuginfo_path,
43
44 .section_address = dwfl_offline_section_address,
45
46 /* We use this table for core files too. */
47 .find_elf = dwfl_build_id_find_elf,
48 };
49
50 /* Get a Dwarf from offline image */
51 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
52 const char *path)
53 {
54 int fd;
55
56 fd = open(path, O_RDONLY);
57 if (fd < 0)
58 return fd;
59
60 dbg->dwfl = dwfl_begin(&offline_callbacks);
61 if (!dbg->dwfl)
62 goto error;
63
64 dwfl_report_begin(dbg->dwfl);
65 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
66 if (!dbg->mod)
67 goto error;
68
69 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
70 if (!dbg->dbg)
71 goto error;
72
73 dwfl_report_end(dbg->dwfl, NULL, NULL);
74
75 return 0;
76 error:
77 if (dbg->dwfl)
78 dwfl_end(dbg->dwfl);
79 else
80 close(fd);
81 memset(dbg, 0, sizeof(*dbg));
82
83 return -ENOENT;
84 }
85
86 static struct debuginfo *__debuginfo__new(const char *path)
87 {
88 struct debuginfo *dbg = zalloc(sizeof(*dbg));
89 if (!dbg)
90 return NULL;
91
92 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
93 zfree(&dbg);
94 if (dbg)
95 pr_debug("Open Debuginfo file: %s\n", path);
96 return dbg;
97 }
98
99 enum dso_binary_type distro_dwarf_types[] = {
100 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
101 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
102 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
103 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
104 DSO_BINARY_TYPE__NOT_FOUND,
105 };
106
107 struct debuginfo *debuginfo__new(const char *path)
108 {
109 enum dso_binary_type *type;
110 char buf[PATH_MAX], nil = '\0';
111 struct dso *dso;
112 struct debuginfo *dinfo = NULL;
113
114 /* Try to open distro debuginfo files */
115 dso = dso__new(path);
116 if (!dso)
117 goto out;
118
119 for (type = distro_dwarf_types;
120 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
121 type++) {
122 if (dso__read_binary_type_filename(dso, *type, &nil,
123 buf, PATH_MAX) < 0)
124 continue;
125 dinfo = __debuginfo__new(buf);
126 }
127 dso__put(dso);
128
129 out:
130 /* if failed to open all distro debuginfo, open given binary */
131 return dinfo ? : __debuginfo__new(path);
132 }
133
134 void debuginfo__delete(struct debuginfo *dbg)
135 {
136 if (dbg) {
137 if (dbg->dwfl)
138 dwfl_end(dbg->dwfl);
139 free(dbg);
140 }
141 }
142
143 /*
144 * Probe finder related functions
145 */
146
147 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
148 {
149 struct probe_trace_arg_ref *ref;
150 ref = zalloc(sizeof(struct probe_trace_arg_ref));
151 if (ref != NULL)
152 ref->offset = offs;
153 return ref;
154 }
155
156 /*
157 * Convert a location into trace_arg.
158 * If tvar == NULL, this just checks variable can be converted.
159 * If fentry == true and vr_die is a parameter, do huristic search
160 * for the location fuzzed by function entry mcount.
161 */
162 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
163 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
164 unsigned int machine,
165 struct probe_trace_arg *tvar)
166 {
167 Dwarf_Attribute attr;
168 Dwarf_Addr tmp = 0;
169 Dwarf_Op *op;
170 size_t nops;
171 unsigned int regn;
172 Dwarf_Word offs = 0;
173 bool ref = false;
174 const char *regs;
175 int ret, ret2 = 0;
176
177 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
178 goto static_var;
179
180 /* Constant value */
181 if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
182 immediate_value_is_supported()) {
183 Dwarf_Sword snum;
184
185 dwarf_formsdata(&attr, &snum);
186 ret = asprintf(&tvar->value, "\\%ld", (long)snum);
187
188 return ret < 0 ? -ENOMEM : 0;
189 }
190
191 /* TODO: handle more than 1 exprs */
192 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
193 return -EINVAL; /* Broken DIE ? */
194 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
195 ret = dwarf_entrypc(sp_die, &tmp);
196 if (ret)
197 return -ENOENT;
198
199 if (probe_conf.show_location_range &&
200 (dwarf_tag(vr_die) == DW_TAG_variable)) {
201 ret2 = -ERANGE;
202 } else if (addr != tmp ||
203 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
204 return -ENOENT;
205 }
206
207 ret = dwarf_highpc(sp_die, &tmp);
208 if (ret)
209 return -ENOENT;
210 /*
211 * This is fuzzed by fentry mcount. We try to find the
212 * parameter location at the earliest address.
213 */
214 for (addr += 1; addr <= tmp; addr++) {
215 if (dwarf_getlocation_addr(&attr, addr, &op,
216 &nops, 1) > 0)
217 goto found;
218 }
219 return -ENOENT;
220 }
221 found:
222 if (nops == 0)
223 /* TODO: Support const_value */
224 return -ENOENT;
225
226 if (op->atom == DW_OP_addr) {
227 static_var:
228 if (!tvar)
229 return ret2;
230 /* Static variables on memory (not stack), make @varname */
231 ret = strlen(dwarf_diename(vr_die));
232 tvar->value = zalloc(ret + 2);
233 if (tvar->value == NULL)
234 return -ENOMEM;
235 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
236 tvar->ref = alloc_trace_arg_ref((long)offs);
237 if (tvar->ref == NULL)
238 return -ENOMEM;
239 return ret2;
240 }
241
242 /* If this is based on frame buffer, set the offset */
243 if (op->atom == DW_OP_fbreg) {
244 if (fb_ops == NULL)
245 return -ENOTSUP;
246 ref = true;
247 offs = op->number;
248 op = &fb_ops[0];
249 }
250
251 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
252 regn = op->atom - DW_OP_breg0;
253 offs += op->number;
254 ref = true;
255 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
256 regn = op->atom - DW_OP_reg0;
257 } else if (op->atom == DW_OP_bregx) {
258 regn = op->number;
259 offs += op->number2;
260 ref = true;
261 } else if (op->atom == DW_OP_regx) {
262 regn = op->number;
263 } else {
264 pr_debug("DW_OP %x is not supported.\n", op->atom);
265 return -ENOTSUP;
266 }
267
268 if (!tvar)
269 return ret2;
270
271 regs = get_dwarf_regstr(regn, machine);
272 if (!regs) {
273 /* This should be a bug in DWARF or this tool */
274 pr_warning("Mapping for the register number %u "
275 "missing on this architecture.\n", regn);
276 return -ENOTSUP;
277 }
278
279 tvar->value = strdup(regs);
280 if (tvar->value == NULL)
281 return -ENOMEM;
282
283 if (ref) {
284 tvar->ref = alloc_trace_arg_ref((long)offs);
285 if (tvar->ref == NULL)
286 return -ENOMEM;
287 }
288 return ret2;
289 }
290
291 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
292
293 static int convert_variable_type(Dwarf_Die *vr_die,
294 struct probe_trace_arg *tvar,
295 const char *cast, bool user_access)
296 {
297 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
298 Dwarf_Die type;
299 char buf[16];
300 char sbuf[STRERR_BUFSIZE];
301 int bsize, boffs, total;
302 int ret;
303 char prefix;
304
305 /* TODO: check all types */
306 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
307 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
308 /* Non string type is OK */
309 /* and respect signedness/hexadecimal cast */
310 tvar->type = strdup(cast);
311 return (tvar->type == NULL) ? -ENOMEM : 0;
312 }
313
314 bsize = dwarf_bitsize(vr_die);
315 if (bsize > 0) {
316 /* This is a bitfield */
317 boffs = dwarf_bitoffset(vr_die);
318 total = dwarf_bytesize(vr_die);
319 if (boffs < 0 || total < 0)
320 return -ENOENT;
321 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
322 BYTES_TO_BITS(total));
323 goto formatted;
324 }
325
326 if (die_get_real_type(vr_die, &type) == NULL) {
327 pr_warning("Failed to get a type information of %s.\n",
328 dwarf_diename(vr_die));
329 return -ENOENT;
330 }
331
332 pr_debug("%s type is %s.\n",
333 dwarf_diename(vr_die), dwarf_diename(&type));
334
335 if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
336 /* String type */
337 ret = dwarf_tag(&type);
338 if (ret != DW_TAG_pointer_type &&
339 ret != DW_TAG_array_type) {
340 pr_warning("Failed to cast into string: "
341 "%s(%s) is not a pointer nor array.\n",
342 dwarf_diename(vr_die), dwarf_diename(&type));
343 return -EINVAL;
344 }
345 if (die_get_real_type(&type, &type) == NULL) {
346 pr_warning("Failed to get a type"
347 " information.\n");
348 return -ENOENT;
349 }
350 if (ret == DW_TAG_pointer_type) {
351 while (*ref_ptr)
352 ref_ptr = &(*ref_ptr)->next;
353 /* Add new reference with offset +0 */
354 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
355 if (*ref_ptr == NULL) {
356 pr_warning("Out of memory error\n");
357 return -ENOMEM;
358 }
359 (*ref_ptr)->user_access = user_access;
360 }
361 if (!die_compare_name(&type, "char") &&
362 !die_compare_name(&type, "unsigned char")) {
363 pr_warning("Failed to cast into string: "
364 "%s is not (unsigned) char *.\n",
365 dwarf_diename(vr_die));
366 return -EINVAL;
367 }
368 tvar->type = strdup(cast);
369 return (tvar->type == NULL) ? -ENOMEM : 0;
370 }
371
372 if (cast && (strcmp(cast, "u") == 0))
373 prefix = 'u';
374 else if (cast && (strcmp(cast, "s") == 0))
375 prefix = 's';
376 else if (cast && (strcmp(cast, "x") == 0) &&
377 probe_type_is_available(PROBE_TYPE_X))
378 prefix = 'x';
379 else
380 prefix = die_is_signed_type(&type) ? 's' :
381 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
382
383 ret = dwarf_bytesize(&type);
384 if (ret <= 0)
385 /* No size ... try to use default type */
386 return 0;
387 ret = BYTES_TO_BITS(ret);
388
389 /* Check the bitwidth */
390 if (ret > MAX_BASIC_TYPE_BITS) {
391 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
392 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
393 ret = MAX_BASIC_TYPE_BITS;
394 }
395 ret = snprintf(buf, 16, "%c%d", prefix, ret);
396
397 formatted:
398 if (ret < 0 || ret >= 16) {
399 if (ret >= 16)
400 ret = -E2BIG;
401 pr_warning("Failed to convert variable type: %s\n",
402 str_error_r(-ret, sbuf, sizeof(sbuf)));
403 return ret;
404 }
405 tvar->type = strdup(buf);
406 if (tvar->type == NULL)
407 return -ENOMEM;
408 return 0;
409 }
410
411 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
412 struct perf_probe_arg_field *field,
413 struct probe_trace_arg_ref **ref_ptr,
414 Dwarf_Die *die_mem, bool user_access)
415 {
416 struct probe_trace_arg_ref *ref = *ref_ptr;
417 Dwarf_Die type;
418 Dwarf_Word offs;
419 int ret, tag;
420
421 pr_debug("converting %s in %s\n", field->name, varname);
422 if (die_get_real_type(vr_die, &type) == NULL) {
423 pr_warning("Failed to get the type of %s.\n", varname);
424 return -ENOENT;
425 }
426 pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
427 (unsigned)dwarf_dieoffset(&type));
428 tag = dwarf_tag(&type);
429
430 if (field->name[0] == '[' &&
431 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
432 /* Save original type for next field or type */
433 memcpy(die_mem, &type, sizeof(*die_mem));
434 /* Get the type of this array */
435 if (die_get_real_type(&type, &type) == NULL) {
436 pr_warning("Failed to get the type of %s.\n", varname);
437 return -ENOENT;
438 }
439 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
440 (unsigned)dwarf_dieoffset(&type));
441 if (tag == DW_TAG_pointer_type) {
442 ref = zalloc(sizeof(struct probe_trace_arg_ref));
443 if (ref == NULL)
444 return -ENOMEM;
445 if (*ref_ptr)
446 (*ref_ptr)->next = ref;
447 else
448 *ref_ptr = ref;
449 }
450 ref->offset += dwarf_bytesize(&type) * field->index;
451 ref->user_access = user_access;
452 goto next;
453 } else if (tag == DW_TAG_pointer_type) {
454 /* Check the pointer and dereference */
455 if (!field->ref) {
456 pr_err("Semantic error: %s must be referred by '->'\n",
457 field->name);
458 return -EINVAL;
459 }
460 /* Get the type pointed by this pointer */
461 if (die_get_real_type(&type, &type) == NULL) {
462 pr_warning("Failed to get the type of %s.\n", varname);
463 return -ENOENT;
464 }
465 /* Verify it is a data structure */
466 tag = dwarf_tag(&type);
467 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
468 pr_warning("%s is not a data structure nor a union.\n",
469 varname);
470 return -EINVAL;
471 }
472
473 ref = zalloc(sizeof(struct probe_trace_arg_ref));
474 if (ref == NULL)
475 return -ENOMEM;
476 if (*ref_ptr)
477 (*ref_ptr)->next = ref;
478 else
479 *ref_ptr = ref;
480 } else {
481 /* Verify it is a data structure */
482 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
483 pr_warning("%s is not a data structure nor a union.\n",
484 varname);
485 return -EINVAL;
486 }
487 if (field->name[0] == '[') {
488 pr_err("Semantic error: %s is not a pointer"
489 " nor array.\n", varname);
490 return -EINVAL;
491 }
492 /* While prcessing unnamed field, we don't care about this */
493 if (field->ref && dwarf_diename(vr_die)) {
494 pr_err("Semantic error: %s must be referred by '.'\n",
495 field->name);
496 return -EINVAL;
497 }
498 if (!ref) {
499 pr_warning("Structure on a register is not "
500 "supported yet.\n");
501 return -ENOTSUP;
502 }
503 }
504
505 if (die_find_member(&type, field->name, die_mem) == NULL) {
506 pr_warning("%s(type:%s) has no member %s.\n", varname,
507 dwarf_diename(&type), field->name);
508 return -EINVAL;
509 }
510
511 /* Get the offset of the field */
512 if (tag == DW_TAG_union_type) {
513 offs = 0;
514 } else {
515 ret = die_get_data_member_location(die_mem, &offs);
516 if (ret < 0) {
517 pr_warning("Failed to get the offset of %s.\n",
518 field->name);
519 return ret;
520 }
521 }
522 ref->offset += (long)offs;
523 ref->user_access = user_access;
524
525 /* If this member is unnamed, we need to reuse this field */
526 if (!dwarf_diename(die_mem))
527 return convert_variable_fields(die_mem, varname, field,
528 &ref, die_mem, user_access);
529
530 next:
531 /* Converting next field */
532 if (field->next)
533 return convert_variable_fields(die_mem, field->name,
534 field->next, &ref, die_mem, user_access);
535 else
536 return 0;
537 }
538
539 static void print_var_not_found(const char *varname)
540 {
541 pr_err("Failed to find the location of the '%s' variable at this address.\n"
542 " Perhaps it has been optimized out.\n"
543 " Use -V with the --range option to show '%s' location range.\n",
544 varname, varname);
545 }
546
547 /* Show a variables in kprobe event format */
548 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
549 {
550 Dwarf_Die die_mem;
551 int ret;
552
553 pr_debug("Converting variable %s into trace event.\n",
554 dwarf_diename(vr_die));
555
556 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
557 &pf->sp_die, pf->machine, pf->tvar);
558 if (ret == -ENOENT && pf->skip_empty_arg)
559 /* This can be found in other place. skip it */
560 return 0;
561 if (ret == -ENOENT || ret == -EINVAL) {
562 print_var_not_found(pf->pvar->var);
563 } else if (ret == -ENOTSUP)
564 pr_err("Sorry, we don't support this variable location yet.\n");
565 else if (ret == 0 && pf->pvar->field) {
566 ret = convert_variable_fields(vr_die, pf->pvar->var,
567 pf->pvar->field, &pf->tvar->ref,
568 &die_mem, pf->pvar->user_access);
569 vr_die = &die_mem;
570 }
571 if (ret == 0)
572 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
573 pf->pvar->user_access);
574 /* *expr will be cached in libdw. Don't free it. */
575 return ret;
576 }
577
578 /* Find a variable in a scope DIE */
579 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
580 {
581 Dwarf_Die vr_die;
582 char *buf, *ptr;
583 int ret = 0;
584
585 /* Copy raw parameters */
586 if (!is_c_varname(pf->pvar->var))
587 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
588
589 if (pf->pvar->name)
590 pf->tvar->name = strdup(pf->pvar->name);
591 else {
592 buf = synthesize_perf_probe_arg(pf->pvar);
593 if (!buf)
594 return -ENOMEM;
595 ptr = strchr(buf, ':'); /* Change type separator to _ */
596 if (ptr)
597 *ptr = '_';
598 pf->tvar->name = buf;
599 }
600 if (pf->tvar->name == NULL)
601 return -ENOMEM;
602
603 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
604 /* Search child die for local variables and parameters. */
605 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
606 /* Search again in global variables */
607 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
608 0, &vr_die)) {
609 if (pf->skip_empty_arg)
610 return 0;
611 pr_warning("Failed to find '%s' in this function.\n",
612 pf->pvar->var);
613 ret = -ENOENT;
614 }
615 }
616 if (ret >= 0)
617 ret = convert_variable(&vr_die, pf);
618
619 return ret;
620 }
621
622 /* Convert subprogram DIE to trace point */
623 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
624 Dwarf_Addr paddr, bool retprobe,
625 const char *function,
626 struct probe_trace_point *tp)
627 {
628 Dwarf_Addr eaddr;
629 GElf_Sym sym;
630 const char *symbol;
631
632 /* Verify the address is correct */
633 if (!dwarf_haspc(sp_die, paddr)) {
634 pr_warning("Specified offset is out of %s\n",
635 dwarf_diename(sp_die));
636 return -EINVAL;
637 }
638
639 /* Try to get actual symbol name from symtab */
640 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
641 if (!symbol) {
642 pr_warning("Failed to find symbol at 0x%lx\n",
643 (unsigned long)paddr);
644 return -ENOENT;
645 }
646 eaddr = sym.st_value;
647
648 tp->offset = (unsigned long)(paddr - eaddr);
649 tp->address = (unsigned long)paddr;
650 tp->symbol = strdup(symbol);
651 if (!tp->symbol)
652 return -ENOMEM;
653
654 /* Return probe must be on the head of a subprogram */
655 if (retprobe) {
656 if (eaddr != paddr) {
657 pr_warning("Failed to find \"%s%%return\",\n"
658 " because %s is an inlined function and"
659 " has no return point.\n", function,
660 function);
661 return -EINVAL;
662 }
663 tp->retprobe = true;
664 }
665
666 return 0;
667 }
668
669 /* Call probe_finder callback with scope DIE */
670 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
671 {
672 Dwarf_Attribute fb_attr;
673 Dwarf_Frame *frame = NULL;
674 size_t nops;
675 int ret;
676
677 if (!sc_die) {
678 pr_err("Caller must pass a scope DIE. Program error.\n");
679 return -EINVAL;
680 }
681
682 /* If not a real subprogram, find a real one */
683 if (!die_is_func_def(sc_die)) {
684 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
685 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
686 pr_warning("Ignoring tail call from %s\n",
687 dwarf_diename(&pf->sp_die));
688 return 0;
689 } else {
690 pr_warning("Failed to find probe point in any "
691 "functions.\n");
692 return -ENOENT;
693 }
694 }
695 } else
696 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
697
698 /* Get the frame base attribute/ops from subprogram */
699 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
700 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
701 if (ret <= 0 || nops == 0) {
702 pf->fb_ops = NULL;
703 #if _ELFUTILS_PREREQ(0, 142)
704 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
705 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
706 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
707 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
708 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
709 pr_warning("Failed to get call frame on 0x%jx\n",
710 (uintmax_t)pf->addr);
711 free(frame);
712 return -ENOENT;
713 }
714 #endif
715 }
716
717 /* Call finder's callback handler */
718 ret = pf->callback(sc_die, pf);
719
720 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
721 free(frame);
722 pf->fb_ops = NULL;
723
724 return ret;
725 }
726
727 struct find_scope_param {
728 const char *function;
729 const char *file;
730 int line;
731 int diff;
732 Dwarf_Die *die_mem;
733 bool found;
734 };
735
736 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
737 {
738 struct find_scope_param *fsp = data;
739 const char *file;
740 int lno;
741
742 /* Skip if declared file name does not match */
743 if (fsp->file) {
744 file = dwarf_decl_file(fn_die);
745 if (!file || strcmp(fsp->file, file) != 0)
746 return 0;
747 }
748 /* If the function name is given, that's what user expects */
749 if (fsp->function) {
750 if (die_match_name(fn_die, fsp->function)) {
751 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
752 fsp->found = true;
753 return 1;
754 }
755 } else {
756 /* With the line number, find the nearest declared DIE */
757 dwarf_decl_line(fn_die, &lno);
758 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
759 /* Keep a candidate and continue */
760 fsp->diff = fsp->line - lno;
761 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
762 fsp->found = true;
763 }
764 }
765 return 0;
766 }
767
768 /* Return innermost DIE */
769 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
770 {
771 struct find_scope_param *fsp = data;
772
773 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
774 fsp->found = true;
775 return 1;
776 }
777
778 /* Find an appropriate scope fits to given conditions */
779 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
780 {
781 struct find_scope_param fsp = {
782 .function = pf->pev->point.function,
783 .file = pf->fname,
784 .line = pf->lno,
785 .diff = INT_MAX,
786 .die_mem = die_mem,
787 .found = false,
788 };
789 int ret;
790
791 ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
792 &fsp);
793 if (!ret && !fsp.found)
794 cu_walk_functions_at(&pf->cu_die, pf->addr,
795 find_inner_scope_cb, &fsp);
796
797 return fsp.found ? die_mem : NULL;
798 }
799
800 static int verify_representive_line(struct probe_finder *pf, const char *fname,
801 int lineno, Dwarf_Addr addr)
802 {
803 const char *__fname, *__func = NULL;
804 Dwarf_Die die_mem;
805 int __lineno;
806
807 /* Verify line number and address by reverse search */
808 if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
809 return 0;
810
811 pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
812 if (strcmp(fname, __fname) || lineno == __lineno)
813 return 0;
814
815 pr_warning("This line is sharing the address with other lines.\n");
816
817 if (pf->pev->point.function) {
818 /* Find best match function name and lines */
819 pf->addr = addr;
820 if (find_best_scope(pf, &die_mem)
821 && die_match_name(&die_mem, pf->pev->point.function)
822 && dwarf_decl_line(&die_mem, &lineno) == 0) {
823 __func = dwarf_diename(&die_mem);
824 __lineno -= lineno;
825 }
826 }
827 pr_warning("Please try to probe at %s:%d instead.\n",
828 __func ? : __fname, __lineno);
829
830 return -ENOENT;
831 }
832
833 static int probe_point_line_walker(const char *fname, int lineno,
834 Dwarf_Addr addr, void *data)
835 {
836 struct probe_finder *pf = data;
837 Dwarf_Die *sc_die, die_mem;
838 int ret;
839
840 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
841 return 0;
842
843 if (verify_representive_line(pf, fname, lineno, addr))
844 return -ENOENT;
845
846 pf->addr = addr;
847 sc_die = find_best_scope(pf, &die_mem);
848 if (!sc_die) {
849 pr_warning("Failed to find scope of probe point.\n");
850 return -ENOENT;
851 }
852
853 ret = call_probe_finder(sc_die, pf);
854
855 /* Continue if no error, because the line will be in inline function */
856 return ret < 0 ? ret : 0;
857 }
858
859 /* Find probe point from its line number */
860 static int find_probe_point_by_line(struct probe_finder *pf)
861 {
862 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
863 }
864
865 /* Find lines which match lazy pattern */
866 static int find_lazy_match_lines(struct intlist *list,
867 const char *fname, const char *pat)
868 {
869 FILE *fp;
870 char *line = NULL;
871 size_t line_len;
872 ssize_t len;
873 int count = 0, linenum = 1;
874 char sbuf[STRERR_BUFSIZE];
875
876 fp = fopen(fname, "r");
877 if (!fp) {
878 pr_warning("Failed to open %s: %s\n", fname,
879 str_error_r(errno, sbuf, sizeof(sbuf)));
880 return -errno;
881 }
882
883 while ((len = getline(&line, &line_len, fp)) > 0) {
884
885 if (line[len - 1] == '\n')
886 line[len - 1] = '\0';
887
888 if (strlazymatch(line, pat)) {
889 intlist__add(list, linenum);
890 count++;
891 }
892 linenum++;
893 }
894
895 if (ferror(fp))
896 count = -errno;
897 free(line);
898 fclose(fp);
899
900 if (count == 0)
901 pr_debug("No matched lines found in %s.\n", fname);
902 return count;
903 }
904
905 static int probe_point_lazy_walker(const char *fname, int lineno,
906 Dwarf_Addr addr, void *data)
907 {
908 struct probe_finder *pf = data;
909 Dwarf_Die *sc_die, die_mem;
910 int ret;
911
912 if (!intlist__has_entry(pf->lcache, lineno) ||
913 strtailcmp(fname, pf->fname) != 0)
914 return 0;
915
916 pr_debug("Probe line found: line:%d addr:0x%llx\n",
917 lineno, (unsigned long long)addr);
918 pf->addr = addr;
919 pf->lno = lineno;
920 sc_die = find_best_scope(pf, &die_mem);
921 if (!sc_die) {
922 pr_warning("Failed to find scope of probe point.\n");
923 return -ENOENT;
924 }
925
926 ret = call_probe_finder(sc_die, pf);
927
928 /*
929 * Continue if no error, because the lazy pattern will match
930 * to other lines
931 */
932 return ret < 0 ? ret : 0;
933 }
934
935 /* Find probe points from lazy pattern */
936 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
937 {
938 int ret = 0;
939 char *fpath;
940
941 if (intlist__empty(pf->lcache)) {
942 const char *comp_dir;
943
944 comp_dir = cu_get_comp_dir(&pf->cu_die);
945 ret = get_real_path(pf->fname, comp_dir, &fpath);
946 if (ret < 0) {
947 pr_warning("Failed to find source file path.\n");
948 return ret;
949 }
950
951 /* Matching lazy line pattern */
952 ret = find_lazy_match_lines(pf->lcache, fpath,
953 pf->pev->point.lazy_line);
954 free(fpath);
955 if (ret <= 0)
956 return ret;
957 }
958
959 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
960 }
961
962 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
963 {
964 struct perf_probe_point *pp = &pf->pev->point;
965
966 /* Not uprobe? */
967 if (!pf->pev->uprobes)
968 return;
969
970 /* Compiled with optimization? */
971 if (die_is_optimized_target(&pf->cu_die))
972 return;
973
974 /* Don't know entrypc? */
975 if (!pf->addr)
976 return;
977
978 /* Only FUNC and FUNC@SRC are eligible. */
979 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
980 pp->offset || pp->abs_address)
981 return;
982
983 /* Not interested in func parameter? */
984 if (!perf_probe_with_var(pf->pev))
985 return;
986
987 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
988 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
989 pf->addr);
990
991 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
992 }
993
994 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
995 {
996 struct probe_finder *pf = data;
997 struct perf_probe_point *pp = &pf->pev->point;
998 Dwarf_Addr addr;
999 int ret;
1000
1001 if (pp->lazy_line)
1002 ret = find_probe_point_lazy(in_die, pf);
1003 else {
1004 /* Get probe address */
1005 if (die_entrypc(in_die, &addr) != 0) {
1006 pr_warning("Failed to get entry address of %s.\n",
1007 dwarf_diename(in_die));
1008 return -ENOENT;
1009 }
1010 if (addr == 0) {
1011 pr_debug("%s has no valid entry address. skipped.\n",
1012 dwarf_diename(in_die));
1013 return -ENOENT;
1014 }
1015 pf->addr = addr;
1016 pf->addr += pp->offset;
1017 pr_debug("found inline addr: 0x%jx\n",
1018 (uintmax_t)pf->addr);
1019
1020 ret = call_probe_finder(in_die, pf);
1021 }
1022
1023 return ret;
1024 }
1025
1026 /* Callback parameter with return value for libdw */
1027 struct dwarf_callback_param {
1028 void *data;
1029 int retval;
1030 };
1031
1032 /* Search function from function name */
1033 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1034 {
1035 struct dwarf_callback_param *param = data;
1036 struct probe_finder *pf = param->data;
1037 struct perf_probe_point *pp = &pf->pev->point;
1038
1039 /* Check tag and diename */
1040 if (!die_is_func_def(sp_die) ||
1041 !die_match_name(sp_die, pp->function))
1042 return DWARF_CB_OK;
1043
1044 /* Check declared file */
1045 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1046 return DWARF_CB_OK;
1047
1048 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1049 (unsigned long)dwarf_dieoffset(sp_die));
1050 pf->fname = dwarf_decl_file(sp_die);
1051 if (pp->line) { /* Function relative line */
1052 dwarf_decl_line(sp_die, &pf->lno);
1053 pf->lno += pp->line;
1054 param->retval = find_probe_point_by_line(pf);
1055 } else if (die_is_func_instance(sp_die)) {
1056 /* Instances always have the entry address */
1057 die_entrypc(sp_die, &pf->addr);
1058 /* But in some case the entry address is 0 */
1059 if (pf->addr == 0) {
1060 pr_debug("%s has no entry PC. Skipped\n",
1061 dwarf_diename(sp_die));
1062 param->retval = 0;
1063 /* Real function */
1064 } else if (pp->lazy_line)
1065 param->retval = find_probe_point_lazy(sp_die, pf);
1066 else {
1067 skip_prologue(sp_die, pf);
1068 pf->addr += pp->offset;
1069 /* TODO: Check the address in this function */
1070 param->retval = call_probe_finder(sp_die, pf);
1071 }
1072 } else if (!probe_conf.no_inlines) {
1073 /* Inlined function: search instances */
1074 param->retval = die_walk_instances(sp_die,
1075 probe_point_inline_cb, (void *)pf);
1076 /* This could be a non-existed inline definition */
1077 if (param->retval == -ENOENT)
1078 param->retval = 0;
1079 }
1080
1081 /* We need to find other candidates */
1082 if (strisglob(pp->function) && param->retval >= 0) {
1083 param->retval = 0; /* We have to clear the result */
1084 return DWARF_CB_OK;
1085 }
1086
1087 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1088 }
1089
1090 static int find_probe_point_by_func(struct probe_finder *pf)
1091 {
1092 struct dwarf_callback_param _param = {.data = (void *)pf,
1093 .retval = 0};
1094 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1095 return _param.retval;
1096 }
1097
1098 struct pubname_callback_param {
1099 char *function;
1100 char *file;
1101 Dwarf_Die *cu_die;
1102 Dwarf_Die *sp_die;
1103 int found;
1104 };
1105
1106 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1107 {
1108 struct pubname_callback_param *param = data;
1109
1110 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1111 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1112 return DWARF_CB_OK;
1113
1114 if (die_match_name(param->sp_die, param->function)) {
1115 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1116 return DWARF_CB_OK;
1117
1118 if (param->file &&
1119 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1120 return DWARF_CB_OK;
1121
1122 param->found = 1;
1123 return DWARF_CB_ABORT;
1124 }
1125 }
1126
1127 return DWARF_CB_OK;
1128 }
1129
1130 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1131 struct probe_finder *pf)
1132 {
1133 struct perf_probe_point *pp = &pf->pev->point;
1134 Dwarf_Off off, noff;
1135 size_t cuhl;
1136 Dwarf_Die *diep;
1137 int ret = 0;
1138
1139 off = 0;
1140 pf->lcache = intlist__new(NULL);
1141 if (!pf->lcache)
1142 return -ENOMEM;
1143
1144 /* Fastpath: lookup by function name from .debug_pubnames section */
1145 if (pp->function && !strisglob(pp->function)) {
1146 struct pubname_callback_param pubname_param = {
1147 .function = pp->function,
1148 .file = pp->file,
1149 .cu_die = &pf->cu_die,
1150 .sp_die = &pf->sp_die,
1151 .found = 0,
1152 };
1153 struct dwarf_callback_param probe_param = {
1154 .data = pf,
1155 };
1156
1157 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1158 &pubname_param, 0);
1159 if (pubname_param.found) {
1160 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1161 if (ret)
1162 goto found;
1163 }
1164 }
1165
1166 /* Loop on CUs (Compilation Unit) */
1167 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1168 /* Get the DIE(Debugging Information Entry) of this CU */
1169 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1170 if (!diep)
1171 continue;
1172
1173 /* Check if target file is included. */
1174 if (pp->file)
1175 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1176 else
1177 pf->fname = NULL;
1178
1179 if (!pp->file || pf->fname) {
1180 if (pp->function)
1181 ret = find_probe_point_by_func(pf);
1182 else if (pp->lazy_line)
1183 ret = find_probe_point_lazy(&pf->cu_die, pf);
1184 else {
1185 pf->lno = pp->line;
1186 ret = find_probe_point_by_line(pf);
1187 }
1188 if (ret < 0)
1189 break;
1190 }
1191 off = noff;
1192 }
1193
1194 found:
1195 intlist__delete(pf->lcache);
1196 pf->lcache = NULL;
1197
1198 return ret;
1199 }
1200
1201 /* Find probe points from debuginfo */
1202 static int debuginfo__find_probes(struct debuginfo *dbg,
1203 struct probe_finder *pf)
1204 {
1205 int ret = 0;
1206 Elf *elf;
1207 GElf_Ehdr ehdr;
1208
1209 if (pf->cfi_eh || pf->cfi_dbg)
1210 return debuginfo__find_probe_location(dbg, pf);
1211
1212 /* Get the call frame information from this dwarf */
1213 elf = dwarf_getelf(dbg->dbg);
1214 if (elf == NULL)
1215 return -EINVAL;
1216
1217 if (gelf_getehdr(elf, &ehdr) == NULL)
1218 return -EINVAL;
1219
1220 pf->machine = ehdr.e_machine;
1221
1222 #if _ELFUTILS_PREREQ(0, 142)
1223 do {
1224 GElf_Shdr shdr;
1225
1226 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1227 shdr.sh_type == SHT_PROGBITS)
1228 pf->cfi_eh = dwarf_getcfi_elf(elf);
1229
1230 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1231 } while (0);
1232 #endif
1233
1234 ret = debuginfo__find_probe_location(dbg, pf);
1235 return ret;
1236 }
1237
1238 struct local_vars_finder {
1239 struct probe_finder *pf;
1240 struct perf_probe_arg *args;
1241 bool vars;
1242 int max_args;
1243 int nargs;
1244 int ret;
1245 };
1246
1247 /* Collect available variables in this scope */
1248 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1249 {
1250 struct local_vars_finder *vf = data;
1251 struct probe_finder *pf = vf->pf;
1252 int tag;
1253
1254 tag = dwarf_tag(die_mem);
1255 if (tag == DW_TAG_formal_parameter ||
1256 (tag == DW_TAG_variable && vf->vars)) {
1257 if (convert_variable_location(die_mem, vf->pf->addr,
1258 vf->pf->fb_ops, &pf->sp_die,
1259 pf->machine, NULL) == 0) {
1260 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1261 if (vf->args[vf->nargs].var == NULL) {
1262 vf->ret = -ENOMEM;
1263 return DIE_FIND_CB_END;
1264 }
1265 pr_debug(" %s", vf->args[vf->nargs].var);
1266 vf->nargs++;
1267 }
1268 }
1269
1270 if (dwarf_haspc(die_mem, vf->pf->addr))
1271 return DIE_FIND_CB_CONTINUE;
1272 else
1273 return DIE_FIND_CB_SIBLING;
1274 }
1275
1276 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1277 struct perf_probe_arg *args)
1278 {
1279 Dwarf_Die die_mem;
1280 int i;
1281 int n = 0;
1282 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1283 .max_args = MAX_PROBE_ARGS, .ret = 0};
1284
1285 for (i = 0; i < pf->pev->nargs; i++) {
1286 /* var never be NULL */
1287 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1288 vf.vars = true;
1289 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1290 /* Copy normal argument */
1291 args[n] = pf->pev->args[i];
1292 n++;
1293 continue;
1294 }
1295 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1296 vf.nargs = n;
1297 /* Special local variables */
1298 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1299 &die_mem);
1300 pr_debug(" (%d)\n", vf.nargs - n);
1301 if (vf.ret < 0)
1302 return vf.ret;
1303 n = vf.nargs;
1304 }
1305 return n;
1306 }
1307
1308 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1309 {
1310 int i;
1311
1312 for (i = 0; i < tf->ntevs; i++) {
1313 if (tf->pf.addr == tf->tevs[i].point.address)
1314 return true;
1315 }
1316 return false;
1317 }
1318
1319 /* Add a found probe point into trace event list */
1320 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1321 {
1322 struct trace_event_finder *tf =
1323 container_of(pf, struct trace_event_finder, pf);
1324 struct perf_probe_point *pp = &pf->pev->point;
1325 struct probe_trace_event *tev;
1326 struct perf_probe_arg *args = NULL;
1327 int ret, i;
1328
1329 /*
1330 * For some reason (e.g. different column assigned to same address)
1331 * This callback can be called with the address which already passed.
1332 * Ignore it first.
1333 */
1334 if (trace_event_finder_overlap(tf))
1335 return 0;
1336
1337 /* Check number of tevs */
1338 if (tf->ntevs == tf->max_tevs) {
1339 pr_warning("Too many( > %d) probe point found.\n",
1340 tf->max_tevs);
1341 return -ERANGE;
1342 }
1343 tev = &tf->tevs[tf->ntevs++];
1344
1345 /* Trace point should be converted from subprogram DIE */
1346 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1347 pp->retprobe, pp->function, &tev->point);
1348 if (ret < 0)
1349 goto end;
1350
1351 tev->point.realname = strdup(dwarf_diename(sc_die));
1352 if (!tev->point.realname) {
1353 ret = -ENOMEM;
1354 goto end;
1355 }
1356
1357 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1358 tev->point.offset);
1359
1360 /* Expand special probe argument if exist */
1361 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1362 if (args == NULL) {
1363 ret = -ENOMEM;
1364 goto end;
1365 }
1366
1367 ret = expand_probe_args(sc_die, pf, args);
1368 if (ret < 0)
1369 goto end;
1370
1371 tev->nargs = ret;
1372 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1373 if (tev->args == NULL) {
1374 ret = -ENOMEM;
1375 goto end;
1376 }
1377
1378 /* Find each argument */
1379 for (i = 0; i < tev->nargs; i++) {
1380 pf->pvar = &args[i];
1381 pf->tvar = &tev->args[i];
1382 /* Variable should be found from scope DIE */
1383 ret = find_variable(sc_die, pf);
1384 if (ret != 0)
1385 break;
1386 }
1387
1388 end:
1389 if (ret) {
1390 clear_probe_trace_event(tev);
1391 tf->ntevs--;
1392 }
1393 free(args);
1394 return ret;
1395 }
1396
1397 static int fill_empty_trace_arg(struct perf_probe_event *pev,
1398 struct probe_trace_event *tevs, int ntevs)
1399 {
1400 char **valp;
1401 char *type;
1402 int i, j, ret;
1403
1404 for (i = 0; i < pev->nargs; i++) {
1405 type = NULL;
1406 for (j = 0; j < ntevs; j++) {
1407 if (tevs[j].args[i].value) {
1408 type = tevs[j].args[i].type;
1409 break;
1410 }
1411 }
1412 if (j == ntevs) {
1413 print_var_not_found(pev->args[i].var);
1414 return -ENOENT;
1415 }
1416 for (j = 0; j < ntevs; j++) {
1417 valp = &tevs[j].args[i].value;
1418 if (*valp)
1419 continue;
1420
1421 ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
1422 if (ret < 0)
1423 return -ENOMEM;
1424 /* Note that type can be NULL */
1425 if (type) {
1426 tevs[j].args[i].type = strdup(type);
1427 if (!tevs[j].args[i].type)
1428 return -ENOMEM;
1429 }
1430 }
1431 }
1432 return 0;
1433 }
1434
1435 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1436 int debuginfo__find_trace_events(struct debuginfo *dbg,
1437 struct perf_probe_event *pev,
1438 struct probe_trace_event **tevs)
1439 {
1440 struct trace_event_finder tf = {
1441 .pf = {.pev = pev, .callback = add_probe_trace_event},
1442 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1443 int ret, i;
1444
1445 /* Allocate result tevs array */
1446 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1447 if (*tevs == NULL)
1448 return -ENOMEM;
1449
1450 tf.tevs = *tevs;
1451 tf.ntevs = 0;
1452
1453 if (pev->nargs != 0 && immediate_value_is_supported())
1454 tf.pf.skip_empty_arg = true;
1455
1456 ret = debuginfo__find_probes(dbg, &tf.pf);
1457 if (ret >= 0 && tf.pf.skip_empty_arg)
1458 ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
1459
1460 if (ret < 0) {
1461 for (i = 0; i < tf.ntevs; i++)
1462 clear_probe_trace_event(&tf.tevs[i]);
1463 zfree(tevs);
1464 return ret;
1465 }
1466
1467 return (ret < 0) ? ret : tf.ntevs;
1468 }
1469
1470 /* Collect available variables in this scope */
1471 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1472 {
1473 struct available_var_finder *af = data;
1474 struct variable_list *vl;
1475 struct strbuf buf = STRBUF_INIT;
1476 int tag, ret;
1477
1478 vl = &af->vls[af->nvls - 1];
1479
1480 tag = dwarf_tag(die_mem);
1481 if (tag == DW_TAG_formal_parameter ||
1482 tag == DW_TAG_variable) {
1483 ret = convert_variable_location(die_mem, af->pf.addr,
1484 af->pf.fb_ops, &af->pf.sp_die,
1485 af->pf.machine, NULL);
1486 if (ret == 0 || ret == -ERANGE) {
1487 int ret2;
1488 bool externs = !af->child;
1489
1490 if (strbuf_init(&buf, 64) < 0)
1491 goto error;
1492
1493 if (probe_conf.show_location_range) {
1494 if (!externs)
1495 ret2 = strbuf_add(&buf,
1496 ret ? "[INV]\t" : "[VAL]\t", 6);
1497 else
1498 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1499 if (ret2)
1500 goto error;
1501 }
1502
1503 ret2 = die_get_varname(die_mem, &buf);
1504
1505 if (!ret2 && probe_conf.show_location_range &&
1506 !externs) {
1507 if (strbuf_addch(&buf, '\t') < 0)
1508 goto error;
1509 ret2 = die_get_var_range(&af->pf.sp_die,
1510 die_mem, &buf);
1511 }
1512
1513 pr_debug("Add new var: %s\n", buf.buf);
1514 if (ret2 == 0) {
1515 strlist__add(vl->vars,
1516 strbuf_detach(&buf, NULL));
1517 }
1518 strbuf_release(&buf);
1519 }
1520 }
1521
1522 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1523 return DIE_FIND_CB_CONTINUE;
1524 else
1525 return DIE_FIND_CB_SIBLING;
1526 error:
1527 strbuf_release(&buf);
1528 pr_debug("Error in strbuf\n");
1529 return DIE_FIND_CB_END;
1530 }
1531
1532 static bool available_var_finder_overlap(struct available_var_finder *af)
1533 {
1534 int i;
1535
1536 for (i = 0; i < af->nvls; i++) {
1537 if (af->pf.addr == af->vls[i].point.address)
1538 return true;
1539 }
1540 return false;
1541
1542 }
1543
1544 /* Add a found vars into available variables list */
1545 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1546 {
1547 struct available_var_finder *af =
1548 container_of(pf, struct available_var_finder, pf);
1549 struct perf_probe_point *pp = &pf->pev->point;
1550 struct variable_list *vl;
1551 Dwarf_Die die_mem;
1552 int ret;
1553
1554 /*
1555 * For some reason (e.g. different column assigned to same address),
1556 * this callback can be called with the address which already passed.
1557 * Ignore it first.
1558 */
1559 if (available_var_finder_overlap(af))
1560 return 0;
1561
1562 /* Check number of tevs */
1563 if (af->nvls == af->max_vls) {
1564 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1565 return -ERANGE;
1566 }
1567 vl = &af->vls[af->nvls++];
1568
1569 /* Trace point should be converted from subprogram DIE */
1570 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1571 pp->retprobe, pp->function, &vl->point);
1572 if (ret < 0)
1573 return ret;
1574
1575 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1576 vl->point.offset);
1577
1578 /* Find local variables */
1579 vl->vars = strlist__new(NULL, NULL);
1580 if (vl->vars == NULL)
1581 return -ENOMEM;
1582 af->child = true;
1583 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1584
1585 /* Find external variables */
1586 if (!probe_conf.show_ext_vars)
1587 goto out;
1588 /* Don't need to search child DIE for external vars. */
1589 af->child = false;
1590 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1591
1592 out:
1593 if (strlist__empty(vl->vars)) {
1594 strlist__delete(vl->vars);
1595 vl->vars = NULL;
1596 }
1597
1598 return ret;
1599 }
1600
1601 /*
1602 * Find available variables at given probe point
1603 * Return the number of found probe points. Return 0 if there is no
1604 * matched probe point. Return <0 if an error occurs.
1605 */
1606 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1607 struct perf_probe_event *pev,
1608 struct variable_list **vls)
1609 {
1610 struct available_var_finder af = {
1611 .pf = {.pev = pev, .callback = add_available_vars},
1612 .mod = dbg->mod,
1613 .max_vls = probe_conf.max_probes};
1614 int ret;
1615
1616 /* Allocate result vls array */
1617 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1618 if (*vls == NULL)
1619 return -ENOMEM;
1620
1621 af.vls = *vls;
1622 af.nvls = 0;
1623
1624 ret = debuginfo__find_probes(dbg, &af.pf);
1625 if (ret < 0) {
1626 /* Free vlist for error */
1627 while (af.nvls--) {
1628 zfree(&af.vls[af.nvls].point.symbol);
1629 strlist__delete(af.vls[af.nvls].vars);
1630 }
1631 zfree(vls);
1632 return ret;
1633 }
1634
1635 return (ret < 0) ? ret : af.nvls;
1636 }
1637
1638 /* For the kernel module, we need a special code to get a DIE */
1639 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1640 bool adjust_offset)
1641 {
1642 int n, i;
1643 Elf32_Word shndx;
1644 Elf_Scn *scn;
1645 Elf *elf;
1646 GElf_Shdr mem, *shdr;
1647 const char *p;
1648
1649 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1650 if (!elf)
1651 return -EINVAL;
1652
1653 /* Get the number of relocations */
1654 n = dwfl_module_relocations(dbg->mod);
1655 if (n < 0)
1656 return -ENOENT;
1657 /* Search the relocation related .text section */
1658 for (i = 0; i < n; i++) {
1659 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1660 if (strcmp(p, ".text") == 0) {
1661 /* OK, get the section header */
1662 scn = elf_getscn(elf, shndx);
1663 if (!scn)
1664 return -ENOENT;
1665 shdr = gelf_getshdr(scn, &mem);
1666 if (!shdr)
1667 return -ENOENT;
1668 *offs = shdr->sh_addr;
1669 if (adjust_offset)
1670 *offs -= shdr->sh_offset;
1671 }
1672 }
1673 return 0;
1674 }
1675
1676 /* Reverse search */
1677 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1678 struct perf_probe_point *ppt)
1679 {
1680 Dwarf_Die cudie, spdie, indie;
1681 Dwarf_Addr _addr = 0, baseaddr = 0;
1682 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1683 int baseline = 0, lineno = 0, ret = 0;
1684
1685 /* We always need to relocate the address for aranges */
1686 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1687 addr += baseaddr;
1688 /* Find cu die */
1689 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1690 pr_warning("Failed to find debug information for address %lx\n",
1691 addr);
1692 ret = -EINVAL;
1693 goto end;
1694 }
1695
1696 /* Find a corresponding line (filename and lineno) */
1697 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1698 /* Don't care whether it failed or not */
1699
1700 /* Find a corresponding function (name, baseline and baseaddr) */
1701 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1702 /* Get function entry information */
1703 func = basefunc = dwarf_diename(&spdie);
1704 if (!func ||
1705 die_entrypc(&spdie, &baseaddr) != 0 ||
1706 dwarf_decl_line(&spdie, &baseline) != 0) {
1707 lineno = 0;
1708 goto post;
1709 }
1710
1711 fname = dwarf_decl_file(&spdie);
1712 if (addr == (unsigned long)baseaddr) {
1713 /* Function entry - Relative line number is 0 */
1714 lineno = baseline;
1715 goto post;
1716 }
1717
1718 /* Track down the inline functions step by step */
1719 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1720 &indie)) {
1721 /* There is an inline function */
1722 if (die_entrypc(&indie, &_addr) == 0 &&
1723 _addr == addr) {
1724 /*
1725 * addr is at an inline function entry.
1726 * In this case, lineno should be the call-site
1727 * line number. (overwrite lineinfo)
1728 */
1729 lineno = die_get_call_lineno(&indie);
1730 fname = die_get_call_file(&indie);
1731 break;
1732 } else {
1733 /*
1734 * addr is in an inline function body.
1735 * Since lineno points one of the lines
1736 * of the inline function, baseline should
1737 * be the entry line of the inline function.
1738 */
1739 tmp = dwarf_diename(&indie);
1740 if (!tmp ||
1741 dwarf_decl_line(&indie, &baseline) != 0)
1742 break;
1743 func = tmp;
1744 spdie = indie;
1745 }
1746 }
1747 /* Verify the lineno and baseline are in a same file */
1748 tmp = dwarf_decl_file(&spdie);
1749 if (!tmp || strcmp(tmp, fname) != 0)
1750 lineno = 0;
1751 }
1752
1753 post:
1754 /* Make a relative line number or an offset */
1755 if (lineno)
1756 ppt->line = lineno - baseline;
1757 else if (basefunc) {
1758 ppt->offset = addr - (unsigned long)baseaddr;
1759 func = basefunc;
1760 }
1761
1762 /* Duplicate strings */
1763 if (func) {
1764 ppt->function = strdup(func);
1765 if (ppt->function == NULL) {
1766 ret = -ENOMEM;
1767 goto end;
1768 }
1769 }
1770 if (fname) {
1771 ppt->file = strdup(fname);
1772 if (ppt->file == NULL) {
1773 zfree(&ppt->function);
1774 ret = -ENOMEM;
1775 goto end;
1776 }
1777 }
1778 end:
1779 if (ret == 0 && (fname || func))
1780 ret = 1; /* Found a point */
1781 return ret;
1782 }
1783
1784 /* Add a line and store the src path */
1785 static int line_range_add_line(const char *src, unsigned int lineno,
1786 struct line_range *lr)
1787 {
1788 /* Copy source path */
1789 if (!lr->path) {
1790 lr->path = strdup(src);
1791 if (lr->path == NULL)
1792 return -ENOMEM;
1793 }
1794 return intlist__add(lr->line_list, lineno);
1795 }
1796
1797 static int line_range_walk_cb(const char *fname, int lineno,
1798 Dwarf_Addr addr __maybe_unused,
1799 void *data)
1800 {
1801 struct line_finder *lf = data;
1802 const char *__fname;
1803 int __lineno;
1804 int err;
1805
1806 if ((strtailcmp(fname, lf->fname) != 0) ||
1807 (lf->lno_s > lineno || lf->lno_e < lineno))
1808 return 0;
1809
1810 /* Make sure this line can be reversable */
1811 if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
1812 && (lineno != __lineno || strcmp(fname, __fname)))
1813 return 0;
1814
1815 err = line_range_add_line(fname, lineno, lf->lr);
1816 if (err < 0 && err != -EEXIST)
1817 return err;
1818
1819 return 0;
1820 }
1821
1822 /* Find line range from its line number */
1823 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1824 {
1825 int ret;
1826
1827 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1828
1829 /* Update status */
1830 if (ret >= 0)
1831 if (!intlist__empty(lf->lr->line_list))
1832 ret = lf->found = 1;
1833 else
1834 ret = 0; /* Lines are not found */
1835 else {
1836 zfree(&lf->lr->path);
1837 }
1838 return ret;
1839 }
1840
1841 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1842 {
1843 int ret = find_line_range_by_line(in_die, data);
1844
1845 /*
1846 * We have to check all instances of inlined function, because
1847 * some execution paths can be optimized out depends on the
1848 * function argument of instances. However, if an error occurs,
1849 * it should be handled by the caller.
1850 */
1851 return ret < 0 ? ret : 0;
1852 }
1853
1854 /* Search function definition from function name */
1855 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1856 {
1857 struct dwarf_callback_param *param = data;
1858 struct line_finder *lf = param->data;
1859 struct line_range *lr = lf->lr;
1860
1861 /* Check declared file */
1862 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1863 return DWARF_CB_OK;
1864
1865 if (die_is_func_def(sp_die) &&
1866 die_match_name(sp_die, lr->function)) {
1867 lf->fname = dwarf_decl_file(sp_die);
1868 dwarf_decl_line(sp_die, &lr->offset);
1869 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1870 lf->lno_s = lr->offset + lr->start;
1871 if (lf->lno_s < 0) /* Overflow */
1872 lf->lno_s = INT_MAX;
1873 lf->lno_e = lr->offset + lr->end;
1874 if (lf->lno_e < 0) /* Overflow */
1875 lf->lno_e = INT_MAX;
1876 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1877 lr->start = lf->lno_s;
1878 lr->end = lf->lno_e;
1879 if (!die_is_func_instance(sp_die))
1880 param->retval = die_walk_instances(sp_die,
1881 line_range_inline_cb, lf);
1882 else
1883 param->retval = find_line_range_by_line(sp_die, lf);
1884 return DWARF_CB_ABORT;
1885 }
1886 return DWARF_CB_OK;
1887 }
1888
1889 static int find_line_range_by_func(struct line_finder *lf)
1890 {
1891 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1892 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1893 return param.retval;
1894 }
1895
1896 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1897 {
1898 struct line_finder lf = {.lr = lr, .found = 0};
1899 int ret = 0;
1900 Dwarf_Off off = 0, noff;
1901 size_t cuhl;
1902 Dwarf_Die *diep;
1903 const char *comp_dir;
1904
1905 /* Fastpath: lookup by function name from .debug_pubnames section */
1906 if (lr->function) {
1907 struct pubname_callback_param pubname_param = {
1908 .function = lr->function, .file = lr->file,
1909 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1910 struct dwarf_callback_param line_range_param = {
1911 .data = (void *)&lf, .retval = 0};
1912
1913 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1914 &pubname_param, 0);
1915 if (pubname_param.found) {
1916 line_range_search_cb(&lf.sp_die, &line_range_param);
1917 if (lf.found)
1918 goto found;
1919 }
1920 }
1921
1922 /* Loop on CUs (Compilation Unit) */
1923 while (!lf.found && ret >= 0) {
1924 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1925 NULL, NULL, NULL) != 0)
1926 break;
1927
1928 /* Get the DIE(Debugging Information Entry) of this CU */
1929 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1930 if (!diep)
1931 continue;
1932
1933 /* Check if target file is included. */
1934 if (lr->file)
1935 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1936 else
1937 lf.fname = 0;
1938
1939 if (!lr->file || lf.fname) {
1940 if (lr->function)
1941 ret = find_line_range_by_func(&lf);
1942 else {
1943 lf.lno_s = lr->start;
1944 lf.lno_e = lr->end;
1945 ret = find_line_range_by_line(NULL, &lf);
1946 }
1947 }
1948 off = noff;
1949 }
1950
1951 found:
1952 /* Store comp_dir */
1953 if (lf.found) {
1954 comp_dir = cu_get_comp_dir(&lf.cu_die);
1955 if (comp_dir) {
1956 lr->comp_dir = strdup(comp_dir);
1957 if (!lr->comp_dir)
1958 ret = -ENOMEM;
1959 }
1960 }
1961
1962 pr_debug("path: %s\n", lr->path);
1963 return (ret < 0) ? ret : lf.found;
1964 }
1965
1966 /*
1967 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1968 * and chop off leading directories that do not exist. Result is passed back as
1969 * a newly allocated path on success.
1970 * Return 0 if file was found and readable, -errno otherwise.
1971 */
1972 int get_real_path(const char *raw_path, const char *comp_dir,
1973 char **new_path)
1974 {
1975 const char *prefix = symbol_conf.source_prefix;
1976
1977 if (!prefix) {
1978 if (raw_path[0] != '/' && comp_dir)
1979 /* If not an absolute path, try to use comp_dir */
1980 prefix = comp_dir;
1981 else {
1982 if (access(raw_path, R_OK) == 0) {
1983 *new_path = strdup(raw_path);
1984 return *new_path ? 0 : -ENOMEM;
1985 } else
1986 return -errno;
1987 }
1988 }
1989
1990 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1991 if (!*new_path)
1992 return -ENOMEM;
1993
1994 for (;;) {
1995 sprintf(*new_path, "%s/%s", prefix, raw_path);
1996
1997 if (access(*new_path, R_OK) == 0)
1998 return 0;
1999
2000 if (!symbol_conf.source_prefix) {
2001 /* In case of searching comp_dir, don't retry */
2002 zfree(new_path);
2003 return -errno;
2004 }
2005
2006 switch (errno) {
2007 case ENAMETOOLONG:
2008 case ENOENT:
2009 case EROFS:
2010 case EFAULT:
2011 raw_path = strchr(++raw_path, '/');
2012 if (!raw_path) {
2013 zfree(new_path);
2014 return -ENOENT;
2015 }
2016 continue;
2017
2018 default:
2019 zfree(new_path);
2020 return -errno;
2021 }
2022 }
2023 }
Linux with added FPC-III support