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Linux 4.8-rc8
[linux/fpc-iii.git] / tools / perf / util / probe-finder.c
blob5c290c682afe7176607fe01f4d29742b1821f1a9
1 /*
2 * probe-finder.c : C expression to kprobe event converter
3 *
4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 *
20 */
21
22 #include <sys/utsname.h>
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <fcntl.h>
26 #include <errno.h>
27 #include <stdio.h>
28 #include <unistd.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <stdarg.h>
32 #include <dwarf-regs.h>
33
34 #include <linux/bitops.h>
35 #include "event.h"
36 #include "dso.h"
37 #include "debug.h"
38 #include "intlist.h"
39 #include "util.h"
40 #include "symbol.h"
41 #include "probe-finder.h"
42
43 /* Kprobe tracer basic type is up to u64 */
44 #define MAX_BASIC_TYPE_BITS 64
45
46 /* Dwarf FL wrappers */
47 static char *debuginfo_path; /* Currently dummy */
48
49 static const Dwfl_Callbacks offline_callbacks = {
50 .find_debuginfo = dwfl_standard_find_debuginfo,
51 .debuginfo_path = &debuginfo_path,
52
53 .section_address = dwfl_offline_section_address,
54
55 /* We use this table for core files too. */
56 .find_elf = dwfl_build_id_find_elf,
57 };
58
59 /* Get a Dwarf from offline image */
60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
61 const char *path)
62 {
63 int fd;
64
65 fd = open(path, O_RDONLY);
66 if (fd < 0)
67 return fd;
68
69 dbg->dwfl = dwfl_begin(&offline_callbacks);
70 if (!dbg->dwfl)
71 goto error;
72
73 dwfl_report_begin(dbg->dwfl);
74 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
75 if (!dbg->mod)
76 goto error;
77
78 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
79 if (!dbg->dbg)
80 goto error;
81
82 dwfl_report_end(dbg->dwfl, NULL, NULL);
83
84 return 0;
85 error:
86 if (dbg->dwfl)
87 dwfl_end(dbg->dwfl);
88 else
89 close(fd);
90 memset(dbg, 0, sizeof(*dbg));
91
92 return -ENOENT;
93 }
94
95 static struct debuginfo *__debuginfo__new(const char *path)
96 {
97 struct debuginfo *dbg = zalloc(sizeof(*dbg));
98 if (!dbg)
99 return NULL;
100
101 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
102 zfree(&dbg);
103 if (dbg)
104 pr_debug("Open Debuginfo file: %s\n", path);
105 return dbg;
106 }
107
108 enum dso_binary_type distro_dwarf_types[] = {
109 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
110 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
111 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
112 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
113 DSO_BINARY_TYPE__NOT_FOUND,
114 };
115
116 struct debuginfo *debuginfo__new(const char *path)
117 {
118 enum dso_binary_type *type;
119 char buf[PATH_MAX], nil = '\0';
120 struct dso *dso;
121 struct debuginfo *dinfo = NULL;
122
123 /* Try to open distro debuginfo files */
124 dso = dso__new(path);
125 if (!dso)
126 goto out;
127
128 for (type = distro_dwarf_types;
129 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
130 type++) {
131 if (dso__read_binary_type_filename(dso, *type, &nil,
132 buf, PATH_MAX) < 0)
133 continue;
134 dinfo = __debuginfo__new(buf);
135 }
136 dso__put(dso);
137
138 out:
139 /* if failed to open all distro debuginfo, open given binary */
140 return dinfo ? : __debuginfo__new(path);
141 }
142
143 void debuginfo__delete(struct debuginfo *dbg)
144 {
145 if (dbg) {
146 if (dbg->dwfl)
147 dwfl_end(dbg->dwfl);
148 free(dbg);
149 }
150 }
151
152 /*
153 * Probe finder related functions
154 */
155
156 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
157 {
158 struct probe_trace_arg_ref *ref;
159 ref = zalloc(sizeof(struct probe_trace_arg_ref));
160 if (ref != NULL)
161 ref->offset = offs;
162 return ref;
163 }
164
165 /*
166 * Convert a location into trace_arg.
167 * If tvar == NULL, this just checks variable can be converted.
168 * If fentry == true and vr_die is a parameter, do huristic search
169 * for the location fuzzed by function entry mcount.
170 */
171 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
172 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
173 struct probe_trace_arg *tvar)
174 {
175 Dwarf_Attribute attr;
176 Dwarf_Addr tmp = 0;
177 Dwarf_Op *op;
178 size_t nops;
179 unsigned int regn;
180 Dwarf_Word offs = 0;
181 bool ref = false;
182 const char *regs;
183 int ret, ret2 = 0;
184
185 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
186 goto static_var;
187
188 /* TODO: handle more than 1 exprs */
189 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
190 return -EINVAL; /* Broken DIE ? */
191 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
192 ret = dwarf_entrypc(sp_die, &tmp);
193 if (ret)
194 return -ENOENT;
195
196 if (probe_conf.show_location_range &&
197 (dwarf_tag(vr_die) == DW_TAG_variable)) {
198 ret2 = -ERANGE;
199 } else if (addr != tmp ||
200 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
201 return -ENOENT;
202 }
203
204 ret = dwarf_highpc(sp_die, &tmp);
205 if (ret)
206 return -ENOENT;
207 /*
208 * This is fuzzed by fentry mcount. We try to find the
209 * parameter location at the earliest address.
210 */
211 for (addr += 1; addr <= tmp; addr++) {
212 if (dwarf_getlocation_addr(&attr, addr, &op,
213 &nops, 1) > 0)
214 goto found;
215 }
216 return -ENOENT;
217 }
218 found:
219 if (nops == 0)
220 /* TODO: Support const_value */
221 return -ENOENT;
222
223 if (op->atom == DW_OP_addr) {
224 static_var:
225 if (!tvar)
226 return ret2;
227 /* Static variables on memory (not stack), make @varname */
228 ret = strlen(dwarf_diename(vr_die));
229 tvar->value = zalloc(ret + 2);
230 if (tvar->value == NULL)
231 return -ENOMEM;
232 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
233 tvar->ref = alloc_trace_arg_ref((long)offs);
234 if (tvar->ref == NULL)
235 return -ENOMEM;
236 return ret2;
237 }
238
239 /* If this is based on frame buffer, set the offset */
240 if (op->atom == DW_OP_fbreg) {
241 if (fb_ops == NULL)
242 return -ENOTSUP;
243 ref = true;
244 offs = op->number;
245 op = &fb_ops[0];
246 }
247
248 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
249 regn = op->atom - DW_OP_breg0;
250 offs += op->number;
251 ref = true;
252 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
253 regn = op->atom - DW_OP_reg0;
254 } else if (op->atom == DW_OP_bregx) {
255 regn = op->number;
256 offs += op->number2;
257 ref = true;
258 } else if (op->atom == DW_OP_regx) {
259 regn = op->number;
260 } else {
261 pr_debug("DW_OP %x is not supported.\n", op->atom);
262 return -ENOTSUP;
263 }
264
265 if (!tvar)
266 return ret2;
267
268 regs = get_arch_regstr(regn);
269 if (!regs) {
270 /* This should be a bug in DWARF or this tool */
271 pr_warning("Mapping for the register number %u "
272 "missing on this architecture.\n", regn);
273 return -ENOTSUP;
274 }
275
276 tvar->value = strdup(regs);
277 if (tvar->value == NULL)
278 return -ENOMEM;
279
280 if (ref) {
281 tvar->ref = alloc_trace_arg_ref((long)offs);
282 if (tvar->ref == NULL)
283 return -ENOMEM;
284 }
285 return ret2;
286 }
287
288 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
289
290 static int convert_variable_type(Dwarf_Die *vr_die,
291 struct probe_trace_arg *tvar,
292 const char *cast)
293 {
294 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
295 Dwarf_Die type;
296 char buf[16];
297 char sbuf[STRERR_BUFSIZE];
298 int bsize, boffs, total;
299 int ret;
300 char sign;
301
302 /* TODO: check all types */
303 if (cast && strcmp(cast, "string") != 0 &&
304 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
305 /* Non string type is OK */
306 /* and respect signedness cast */
307 tvar->type = strdup(cast);
308 return (tvar->type == NULL) ? -ENOMEM : 0;
309 }
310
311 bsize = dwarf_bitsize(vr_die);
312 if (bsize > 0) {
313 /* This is a bitfield */
314 boffs = dwarf_bitoffset(vr_die);
315 total = dwarf_bytesize(vr_die);
316 if (boffs < 0 || total < 0)
317 return -ENOENT;
318 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
319 BYTES_TO_BITS(total));
320 goto formatted;
321 }
322
323 if (die_get_real_type(vr_die, &type) == NULL) {
324 pr_warning("Failed to get a type information of %s.\n",
325 dwarf_diename(vr_die));
326 return -ENOENT;
327 }
328
329 pr_debug("%s type is %s.\n",
330 dwarf_diename(vr_die), dwarf_diename(&type));
331
332 if (cast && strcmp(cast, "string") == 0) { /* String type */
333 ret = dwarf_tag(&type);
334 if (ret != DW_TAG_pointer_type &&
335 ret != DW_TAG_array_type) {
336 pr_warning("Failed to cast into string: "
337 "%s(%s) is not a pointer nor array.\n",
338 dwarf_diename(vr_die), dwarf_diename(&type));
339 return -EINVAL;
340 }
341 if (die_get_real_type(&type, &type) == NULL) {
342 pr_warning("Failed to get a type"
343 " information.\n");
344 return -ENOENT;
345 }
346 if (ret == DW_TAG_pointer_type) {
347 while (*ref_ptr)
348 ref_ptr = &(*ref_ptr)->next;
349 /* Add new reference with offset +0 */
350 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
351 if (*ref_ptr == NULL) {
352 pr_warning("Out of memory error\n");
353 return -ENOMEM;
354 }
355 }
356 if (!die_compare_name(&type, "char") &&
357 !die_compare_name(&type, "unsigned char")) {
358 pr_warning("Failed to cast into string: "
359 "%s is not (unsigned) char *.\n",
360 dwarf_diename(vr_die));
361 return -EINVAL;
362 }
363 tvar->type = strdup(cast);
364 return (tvar->type == NULL) ? -ENOMEM : 0;
365 }
366
367 if (cast && (strcmp(cast, "u") == 0))
368 sign = 'u';
369 else if (cast && (strcmp(cast, "s") == 0))
370 sign = 's';
371 else
372 sign = die_is_signed_type(&type) ? 's' : 'u';
373
374 ret = dwarf_bytesize(&type);
375 if (ret <= 0)
376 /* No size ... try to use default type */
377 return 0;
378 ret = BYTES_TO_BITS(ret);
379
380 /* Check the bitwidth */
381 if (ret > MAX_BASIC_TYPE_BITS) {
382 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
383 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
384 ret = MAX_BASIC_TYPE_BITS;
385 }
386 ret = snprintf(buf, 16, "%c%d", sign, ret);
387
388 formatted:
389 if (ret < 0 || ret >= 16) {
390 if (ret >= 16)
391 ret = -E2BIG;
392 pr_warning("Failed to convert variable type: %s\n",
393 str_error_r(-ret, sbuf, sizeof(sbuf)));
394 return ret;
395 }
396 tvar->type = strdup(buf);
397 if (tvar->type == NULL)
398 return -ENOMEM;
399 return 0;
400 }
401
402 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
403 struct perf_probe_arg_field *field,
404 struct probe_trace_arg_ref **ref_ptr,
405 Dwarf_Die *die_mem)
406 {
407 struct probe_trace_arg_ref *ref = *ref_ptr;
408 Dwarf_Die type;
409 Dwarf_Word offs;
410 int ret, tag;
411
412 pr_debug("converting %s in %s\n", field->name, varname);
413 if (die_get_real_type(vr_die, &type) == NULL) {
414 pr_warning("Failed to get the type of %s.\n", varname);
415 return -ENOENT;
416 }
417 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
418 tag = dwarf_tag(&type);
419
420 if (field->name[0] == '[' &&
421 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
422 if (field->next)
423 /* Save original type for next field */
424 memcpy(die_mem, &type, sizeof(*die_mem));
425 /* Get the type of this array */
426 if (die_get_real_type(&type, &type) == NULL) {
427 pr_warning("Failed to get the type of %s.\n", varname);
428 return -ENOENT;
429 }
430 pr_debug2("Array real type: (%x)\n",
431 (unsigned)dwarf_dieoffset(&type));
432 if (tag == DW_TAG_pointer_type) {
433 ref = zalloc(sizeof(struct probe_trace_arg_ref));
434 if (ref == NULL)
435 return -ENOMEM;
436 if (*ref_ptr)
437 (*ref_ptr)->next = ref;
438 else
439 *ref_ptr = ref;
440 }
441 ref->offset += dwarf_bytesize(&type) * field->index;
442 if (!field->next)
443 /* Save vr_die for converting types */
444 memcpy(die_mem, vr_die, sizeof(*die_mem));
445 goto next;
446 } else if (tag == DW_TAG_pointer_type) {
447 /* Check the pointer and dereference */
448 if (!field->ref) {
449 pr_err("Semantic error: %s must be referred by '->'\n",
450 field->name);
451 return -EINVAL;
452 }
453 /* Get the type pointed by this pointer */
454 if (die_get_real_type(&type, &type) == NULL) {
455 pr_warning("Failed to get the type of %s.\n", varname);
456 return -ENOENT;
457 }
458 /* Verify it is a data structure */
459 tag = dwarf_tag(&type);
460 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
461 pr_warning("%s is not a data structure nor an union.\n",
462 varname);
463 return -EINVAL;
464 }
465
466 ref = zalloc(sizeof(struct probe_trace_arg_ref));
467 if (ref == NULL)
468 return -ENOMEM;
469 if (*ref_ptr)
470 (*ref_ptr)->next = ref;
471 else
472 *ref_ptr = ref;
473 } else {
474 /* Verify it is a data structure */
475 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
476 pr_warning("%s is not a data structure nor an union.\n",
477 varname);
478 return -EINVAL;
479 }
480 if (field->name[0] == '[') {
481 pr_err("Semantic error: %s is not a pointer"
482 " nor array.\n", varname);
483 return -EINVAL;
484 }
485 /* While prcessing unnamed field, we don't care about this */
486 if (field->ref && dwarf_diename(vr_die)) {
487 pr_err("Semantic error: %s must be referred by '.'\n",
488 field->name);
489 return -EINVAL;
490 }
491 if (!ref) {
492 pr_warning("Structure on a register is not "
493 "supported yet.\n");
494 return -ENOTSUP;
495 }
496 }
497
498 if (die_find_member(&type, field->name, die_mem) == NULL) {
499 pr_warning("%s(type:%s) has no member %s.\n", varname,
500 dwarf_diename(&type), field->name);
501 return -EINVAL;
502 }
503
504 /* Get the offset of the field */
505 if (tag == DW_TAG_union_type) {
506 offs = 0;
507 } else {
508 ret = die_get_data_member_location(die_mem, &offs);
509 if (ret < 0) {
510 pr_warning("Failed to get the offset of %s.\n",
511 field->name);
512 return ret;
513 }
514 }
515 ref->offset += (long)offs;
516
517 /* If this member is unnamed, we need to reuse this field */
518 if (!dwarf_diename(die_mem))
519 return convert_variable_fields(die_mem, varname, field,
520 &ref, die_mem);
521
522 next:
523 /* Converting next field */
524 if (field->next)
525 return convert_variable_fields(die_mem, field->name,
526 field->next, &ref, die_mem);
527 else
528 return 0;
529 }
530
531 /* Show a variables in kprobe event format */
532 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
533 {
534 Dwarf_Die die_mem;
535 int ret;
536
537 pr_debug("Converting variable %s into trace event.\n",
538 dwarf_diename(vr_die));
539
540 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
541 &pf->sp_die, pf->tvar);
542 if (ret == -ENOENT || ret == -EINVAL) {
543 pr_err("Failed to find the location of the '%s' variable at this address.\n"
544 " Perhaps it has been optimized out.\n"
545 " Use -V with the --range option to show '%s' location range.\n",
546 pf->pvar->var, pf->pvar->var);
547 } else if (ret == -ENOTSUP)
548 pr_err("Sorry, we don't support this variable location yet.\n");
549 else if (ret == 0 && pf->pvar->field) {
550 ret = convert_variable_fields(vr_die, pf->pvar->var,
551 pf->pvar->field, &pf->tvar->ref,
552 &die_mem);
553 vr_die = &die_mem;
554 }
555 if (ret == 0)
556 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
557 /* *expr will be cached in libdw. Don't free it. */
558 return ret;
559 }
560
561 /* Find a variable in a scope DIE */
562 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
563 {
564 Dwarf_Die vr_die;
565 char *buf, *ptr;
566 int ret = 0;
567
568 /* Copy raw parameters */
569 if (!is_c_varname(pf->pvar->var))
570 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
571
572 if (pf->pvar->name)
573 pf->tvar->name = strdup(pf->pvar->name);
574 else {
575 buf = synthesize_perf_probe_arg(pf->pvar);
576 if (!buf)
577 return -ENOMEM;
578 ptr = strchr(buf, ':'); /* Change type separator to _ */
579 if (ptr)
580 *ptr = '_';
581 pf->tvar->name = buf;
582 }
583 if (pf->tvar->name == NULL)
584 return -ENOMEM;
585
586 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
587 /* Search child die for local variables and parameters. */
588 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
589 /* Search again in global variables */
590 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
591 0, &vr_die)) {
592 pr_warning("Failed to find '%s' in this function.\n",
593 pf->pvar->var);
594 ret = -ENOENT;
595 }
596 }
597 if (ret >= 0)
598 ret = convert_variable(&vr_die, pf);
599
600 return ret;
601 }
602
603 /* Convert subprogram DIE to trace point */
604 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
605 Dwarf_Addr paddr, bool retprobe,
606 const char *function,
607 struct probe_trace_point *tp)
608 {
609 Dwarf_Addr eaddr, highaddr;
610 GElf_Sym sym;
611 const char *symbol;
612
613 /* Verify the address is correct */
614 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
615 pr_warning("Failed to get entry address of %s\n",
616 dwarf_diename(sp_die));
617 return -ENOENT;
618 }
619 if (dwarf_highpc(sp_die, &highaddr) != 0) {
620 pr_warning("Failed to get end address of %s\n",
621 dwarf_diename(sp_die));
622 return -ENOENT;
623 }
624 if (paddr > highaddr) {
625 pr_warning("Offset specified is greater than size of %s\n",
626 dwarf_diename(sp_die));
627 return -EINVAL;
628 }
629
630 symbol = dwarf_diename(sp_die);
631 if (!symbol) {
632 /* Try to get the symbol name from symtab */
633 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
634 if (!symbol) {
635 pr_warning("Failed to find symbol at 0x%lx\n",
636 (unsigned long)paddr);
637 return -ENOENT;
638 }
639 eaddr = sym.st_value;
640 }
641 tp->offset = (unsigned long)(paddr - eaddr);
642 tp->address = (unsigned long)paddr;
643 tp->symbol = strdup(symbol);
644 if (!tp->symbol)
645 return -ENOMEM;
646
647 /* Return probe must be on the head of a subprogram */
648 if (retprobe) {
649 if (eaddr != paddr) {
650 pr_warning("Failed to find \"%s%%return\",\n"
651 " because %s is an inlined function and"
652 " has no return point.\n", function,
653 function);
654 return -EINVAL;
655 }
656 tp->retprobe = true;
657 }
658
659 return 0;
660 }
661
662 /* Call probe_finder callback with scope DIE */
663 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
664 {
665 Dwarf_Attribute fb_attr;
666 Dwarf_Frame *frame = NULL;
667 size_t nops;
668 int ret;
669
670 if (!sc_die) {
671 pr_err("Caller must pass a scope DIE. Program error.\n");
672 return -EINVAL;
673 }
674
675 /* If not a real subprogram, find a real one */
676 if (!die_is_func_def(sc_die)) {
677 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
678 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
679 pr_warning("Ignoring tail call from %s\n",
680 dwarf_diename(&pf->sp_die));
681 return 0;
682 } else {
683 pr_warning("Failed to find probe point in any "
684 "functions.\n");
685 return -ENOENT;
686 }
687 }
688 } else
689 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
690
691 /* Get the frame base attribute/ops from subprogram */
692 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
693 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
694 if (ret <= 0 || nops == 0) {
695 pf->fb_ops = NULL;
696 #if _ELFUTILS_PREREQ(0, 142)
697 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
698 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
699 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
700 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
701 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
702 pr_warning("Failed to get call frame on 0x%jx\n",
703 (uintmax_t)pf->addr);
704 free(frame);
705 return -ENOENT;
706 }
707 #endif
708 }
709
710 /* Call finder's callback handler */
711 ret = pf->callback(sc_die, pf);
712
713 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
714 free(frame);
715 pf->fb_ops = NULL;
716
717 return ret;
718 }
719
720 struct find_scope_param {
721 const char *function;
722 const char *file;
723 int line;
724 int diff;
725 Dwarf_Die *die_mem;
726 bool found;
727 };
728
729 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
730 {
731 struct find_scope_param *fsp = data;
732 const char *file;
733 int lno;
734
735 /* Skip if declared file name does not match */
736 if (fsp->file) {
737 file = dwarf_decl_file(fn_die);
738 if (!file || strcmp(fsp->file, file) != 0)
739 return 0;
740 }
741 /* If the function name is given, that's what user expects */
742 if (fsp->function) {
743 if (die_match_name(fn_die, fsp->function)) {
744 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
745 fsp->found = true;
746 return 1;
747 }
748 } else {
749 /* With the line number, find the nearest declared DIE */
750 dwarf_decl_line(fn_die, &lno);
751 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
752 /* Keep a candidate and continue */
753 fsp->diff = fsp->line - lno;
754 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
755 fsp->found = true;
756 }
757 }
758 return 0;
759 }
760
761 /* Find an appropriate scope fits to given conditions */
762 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
763 {
764 struct find_scope_param fsp = {
765 .function = pf->pev->point.function,
766 .file = pf->fname,
767 .line = pf->lno,
768 .diff = INT_MAX,
769 .die_mem = die_mem,
770 .found = false,
771 };
772
773 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
774
775 return fsp.found ? die_mem : NULL;
776 }
777
778 static int probe_point_line_walker(const char *fname, int lineno,
779 Dwarf_Addr addr, void *data)
780 {
781 struct probe_finder *pf = data;
782 Dwarf_Die *sc_die, die_mem;
783 int ret;
784
785 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
786 return 0;
787
788 pf->addr = addr;
789 sc_die = find_best_scope(pf, &die_mem);
790 if (!sc_die) {
791 pr_warning("Failed to find scope of probe point.\n");
792 return -ENOENT;
793 }
794
795 ret = call_probe_finder(sc_die, pf);
796
797 /* Continue if no error, because the line will be in inline function */
798 return ret < 0 ? ret : 0;
799 }
800
801 /* Find probe point from its line number */
802 static int find_probe_point_by_line(struct probe_finder *pf)
803 {
804 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
805 }
806
807 /* Find lines which match lazy pattern */
808 static int find_lazy_match_lines(struct intlist *list,
809 const char *fname, const char *pat)
810 {
811 FILE *fp;
812 char *line = NULL;
813 size_t line_len;
814 ssize_t len;
815 int count = 0, linenum = 1;
816 char sbuf[STRERR_BUFSIZE];
817
818 fp = fopen(fname, "r");
819 if (!fp) {
820 pr_warning("Failed to open %s: %s\n", fname,
821 str_error_r(errno, sbuf, sizeof(sbuf)));
822 return -errno;
823 }
824
825 while ((len = getline(&line, &line_len, fp)) > 0) {
826
827 if (line[len - 1] == '\n')
828 line[len - 1] = '\0';
829
830 if (strlazymatch(line, pat)) {
831 intlist__add(list, linenum);
832 count++;
833 }
834 linenum++;
835 }
836
837 if (ferror(fp))
838 count = -errno;
839 free(line);
840 fclose(fp);
841
842 if (count == 0)
843 pr_debug("No matched lines found in %s.\n", fname);
844 return count;
845 }
846
847 static int probe_point_lazy_walker(const char *fname, int lineno,
848 Dwarf_Addr addr, void *data)
849 {
850 struct probe_finder *pf = data;
851 Dwarf_Die *sc_die, die_mem;
852 int ret;
853
854 if (!intlist__has_entry(pf->lcache, lineno) ||
855 strtailcmp(fname, pf->fname) != 0)
856 return 0;
857
858 pr_debug("Probe line found: line:%d addr:0x%llx\n",
859 lineno, (unsigned long long)addr);
860 pf->addr = addr;
861 pf->lno = lineno;
862 sc_die = find_best_scope(pf, &die_mem);
863 if (!sc_die) {
864 pr_warning("Failed to find scope of probe point.\n");
865 return -ENOENT;
866 }
867
868 ret = call_probe_finder(sc_die, pf);
869
870 /*
871 * Continue if no error, because the lazy pattern will match
872 * to other lines
873 */
874 return ret < 0 ? ret : 0;
875 }
876
877 /* Find probe points from lazy pattern */
878 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
879 {
880 int ret = 0;
881 char *fpath;
882
883 if (intlist__empty(pf->lcache)) {
884 const char *comp_dir;
885
886 comp_dir = cu_get_comp_dir(&pf->cu_die);
887 ret = get_real_path(pf->fname, comp_dir, &fpath);
888 if (ret < 0) {
889 pr_warning("Failed to find source file path.\n");
890 return ret;
891 }
892
893 /* Matching lazy line pattern */
894 ret = find_lazy_match_lines(pf->lcache, fpath,
895 pf->pev->point.lazy_line);
896 free(fpath);
897 if (ret <= 0)
898 return ret;
899 }
900
901 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
902 }
903
904 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
905 {
906 struct probe_finder *pf = data;
907 struct perf_probe_point *pp = &pf->pev->point;
908 Dwarf_Addr addr;
909 int ret;
910
911 if (pp->lazy_line)
912 ret = find_probe_point_lazy(in_die, pf);
913 else {
914 /* Get probe address */
915 if (dwarf_entrypc(in_die, &addr) != 0) {
916 pr_warning("Failed to get entry address of %s.\n",
917 dwarf_diename(in_die));
918 return -ENOENT;
919 }
920 pf->addr = addr;
921 pf->addr += pp->offset;
922 pr_debug("found inline addr: 0x%jx\n",
923 (uintmax_t)pf->addr);
924
925 ret = call_probe_finder(in_die, pf);
926 }
927
928 return ret;
929 }
930
931 /* Callback parameter with return value for libdw */
932 struct dwarf_callback_param {
933 void *data;
934 int retval;
935 };
936
937 /* Search function from function name */
938 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
939 {
940 struct dwarf_callback_param *param = data;
941 struct probe_finder *pf = param->data;
942 struct perf_probe_point *pp = &pf->pev->point;
943
944 /* Check tag and diename */
945 if (!die_is_func_def(sp_die) ||
946 !die_match_name(sp_die, pp->function))
947 return DWARF_CB_OK;
948
949 /* Check declared file */
950 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
951 return DWARF_CB_OK;
952
953 pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
954 pf->fname = dwarf_decl_file(sp_die);
955 if (pp->line) { /* Function relative line */
956 dwarf_decl_line(sp_die, &pf->lno);
957 pf->lno += pp->line;
958 param->retval = find_probe_point_by_line(pf);
959 } else if (die_is_func_instance(sp_die)) {
960 /* Instances always have the entry address */
961 dwarf_entrypc(sp_die, &pf->addr);
962 /* Real function */
963 if (pp->lazy_line)
964 param->retval = find_probe_point_lazy(sp_die, pf);
965 else {
966 pf->addr += pp->offset;
967 /* TODO: Check the address in this function */
968 param->retval = call_probe_finder(sp_die, pf);
969 }
970 } else if (!probe_conf.no_inlines) {
971 /* Inlined function: search instances */
972 param->retval = die_walk_instances(sp_die,
973 probe_point_inline_cb, (void *)pf);
974 /* This could be a non-existed inline definition */
975 if (param->retval == -ENOENT && strisglob(pp->function))
976 param->retval = 0;
977 }
978
979 /* We need to find other candidates */
980 if (strisglob(pp->function) && param->retval >= 0) {
981 param->retval = 0; /* We have to clear the result */
982 return DWARF_CB_OK;
983 }
984
985 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
986 }
987
988 static int find_probe_point_by_func(struct probe_finder *pf)
989 {
990 struct dwarf_callback_param _param = {.data = (void *)pf,
991 .retval = 0};
992 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
993 return _param.retval;
994 }
995
996 struct pubname_callback_param {
997 char *function;
998 char *file;
999 Dwarf_Die *cu_die;
1000 Dwarf_Die *sp_die;
1001 int found;
1002 };
1003
1004 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1005 {
1006 struct pubname_callback_param *param = data;
1007
1008 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1009 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1010 return DWARF_CB_OK;
1011
1012 if (die_match_name(param->sp_die, param->function)) {
1013 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1014 return DWARF_CB_OK;
1015
1016 if (param->file &&
1017 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1018 return DWARF_CB_OK;
1019
1020 param->found = 1;
1021 return DWARF_CB_ABORT;
1022 }
1023 }
1024
1025 return DWARF_CB_OK;
1026 }
1027
1028 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1029 struct probe_finder *pf)
1030 {
1031 struct perf_probe_point *pp = &pf->pev->point;
1032 Dwarf_Off off, noff;
1033 size_t cuhl;
1034 Dwarf_Die *diep;
1035 int ret = 0;
1036
1037 off = 0;
1038 pf->lcache = intlist__new(NULL);
1039 if (!pf->lcache)
1040 return -ENOMEM;
1041
1042 /* Fastpath: lookup by function name from .debug_pubnames section */
1043 if (pp->function && !strisglob(pp->function)) {
1044 struct pubname_callback_param pubname_param = {
1045 .function = pp->function,
1046 .file = pp->file,
1047 .cu_die = &pf->cu_die,
1048 .sp_die = &pf->sp_die,
1049 .found = 0,
1050 };
1051 struct dwarf_callback_param probe_param = {
1052 .data = pf,
1053 };
1054
1055 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1056 &pubname_param, 0);
1057 if (pubname_param.found) {
1058 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1059 if (ret)
1060 goto found;
1061 }
1062 }
1063
1064 /* Loop on CUs (Compilation Unit) */
1065 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1066 /* Get the DIE(Debugging Information Entry) of this CU */
1067 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1068 if (!diep)
1069 continue;
1070
1071 /* Check if target file is included. */
1072 if (pp->file)
1073 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1074 else
1075 pf->fname = NULL;
1076
1077 if (!pp->file || pf->fname) {
1078 if (pp->function)
1079 ret = find_probe_point_by_func(pf);
1080 else if (pp->lazy_line)
1081 ret = find_probe_point_lazy(&pf->cu_die, pf);
1082 else {
1083 pf->lno = pp->line;
1084 ret = find_probe_point_by_line(pf);
1085 }
1086 if (ret < 0)
1087 break;
1088 }
1089 off = noff;
1090 }
1091
1092 found:
1093 intlist__delete(pf->lcache);
1094 pf->lcache = NULL;
1095
1096 return ret;
1097 }
1098
1099 /* Find probe points from debuginfo */
1100 static int debuginfo__find_probes(struct debuginfo *dbg,
1101 struct probe_finder *pf)
1102 {
1103 int ret = 0;
1104
1105 #if _ELFUTILS_PREREQ(0, 142)
1106 Elf *elf;
1107 GElf_Ehdr ehdr;
1108 GElf_Shdr shdr;
1109
1110 if (pf->cfi_eh || pf->cfi_dbg)
1111 return debuginfo__find_probe_location(dbg, pf);
1112
1113 /* Get the call frame information from this dwarf */
1114 elf = dwarf_getelf(dbg->dbg);
1115 if (elf == NULL)
1116 return -EINVAL;
1117
1118 if (gelf_getehdr(elf, &ehdr) == NULL)
1119 return -EINVAL;
1120
1121 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1122 shdr.sh_type == SHT_PROGBITS)
1123 pf->cfi_eh = dwarf_getcfi_elf(elf);
1124
1125 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1126 #endif
1127
1128 ret = debuginfo__find_probe_location(dbg, pf);
1129 return ret;
1130 }
1131
1132 struct local_vars_finder {
1133 struct probe_finder *pf;
1134 struct perf_probe_arg *args;
1135 bool vars;
1136 int max_args;
1137 int nargs;
1138 int ret;
1139 };
1140
1141 /* Collect available variables in this scope */
1142 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1143 {
1144 struct local_vars_finder *vf = data;
1145 struct probe_finder *pf = vf->pf;
1146 int tag;
1147
1148 tag = dwarf_tag(die_mem);
1149 if (tag == DW_TAG_formal_parameter ||
1150 (tag == DW_TAG_variable && vf->vars)) {
1151 if (convert_variable_location(die_mem, vf->pf->addr,
1152 vf->pf->fb_ops, &pf->sp_die,
1153 NULL) == 0) {
1154 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1155 if (vf->args[vf->nargs].var == NULL) {
1156 vf->ret = -ENOMEM;
1157 return DIE_FIND_CB_END;
1158 }
1159 pr_debug(" %s", vf->args[vf->nargs].var);
1160 vf->nargs++;
1161 }
1162 }
1163
1164 if (dwarf_haspc(die_mem, vf->pf->addr))
1165 return DIE_FIND_CB_CONTINUE;
1166 else
1167 return DIE_FIND_CB_SIBLING;
1168 }
1169
1170 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1171 struct perf_probe_arg *args)
1172 {
1173 Dwarf_Die die_mem;
1174 int i;
1175 int n = 0;
1176 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1177 .max_args = MAX_PROBE_ARGS, .ret = 0};
1178
1179 for (i = 0; i < pf->pev->nargs; i++) {
1180 /* var never be NULL */
1181 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1182 vf.vars = true;
1183 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1184 /* Copy normal argument */
1185 args[n] = pf->pev->args[i];
1186 n++;
1187 continue;
1188 }
1189 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1190 vf.nargs = n;
1191 /* Special local variables */
1192 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1193 &die_mem);
1194 pr_debug(" (%d)\n", vf.nargs - n);
1195 if (vf.ret < 0)
1196 return vf.ret;
1197 n = vf.nargs;
1198 }
1199 return n;
1200 }
1201
1202 /* Add a found probe point into trace event list */
1203 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1204 {
1205 struct trace_event_finder *tf =
1206 container_of(pf, struct trace_event_finder, pf);
1207 struct perf_probe_point *pp = &pf->pev->point;
1208 struct probe_trace_event *tev;
1209 struct perf_probe_arg *args = NULL;
1210 int ret, i;
1211
1212 /* Check number of tevs */
1213 if (tf->ntevs == tf->max_tevs) {
1214 pr_warning("Too many( > %d) probe point found.\n",
1215 tf->max_tevs);
1216 return -ERANGE;
1217 }
1218 tev = &tf->tevs[tf->ntevs++];
1219
1220 /* Trace point should be converted from subprogram DIE */
1221 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1222 pp->retprobe, pp->function, &tev->point);
1223 if (ret < 0)
1224 goto end;
1225
1226 tev->point.realname = strdup(dwarf_diename(sc_die));
1227 if (!tev->point.realname) {
1228 ret = -ENOMEM;
1229 goto end;
1230 }
1231
1232 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1233 tev->point.offset);
1234
1235 /* Expand special probe argument if exist */
1236 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1237 if (args == NULL) {
1238 ret = -ENOMEM;
1239 goto end;
1240 }
1241
1242 ret = expand_probe_args(sc_die, pf, args);
1243 if (ret < 0)
1244 goto end;
1245
1246 tev->nargs = ret;
1247 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1248 if (tev->args == NULL) {
1249 ret = -ENOMEM;
1250 goto end;
1251 }
1252
1253 /* Find each argument */
1254 for (i = 0; i < tev->nargs; i++) {
1255 pf->pvar = &args[i];
1256 pf->tvar = &tev->args[i];
1257 /* Variable should be found from scope DIE */
1258 ret = find_variable(sc_die, pf);
1259 if (ret != 0)
1260 break;
1261 }
1262
1263 end:
1264 if (ret) {
1265 clear_probe_trace_event(tev);
1266 tf->ntevs--;
1267 }
1268 free(args);
1269 return ret;
1270 }
1271
1272 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1273 int debuginfo__find_trace_events(struct debuginfo *dbg,
1274 struct perf_probe_event *pev,
1275 struct probe_trace_event **tevs)
1276 {
1277 struct trace_event_finder tf = {
1278 .pf = {.pev = pev, .callback = add_probe_trace_event},
1279 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1280 int ret, i;
1281
1282 /* Allocate result tevs array */
1283 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1284 if (*tevs == NULL)
1285 return -ENOMEM;
1286
1287 tf.tevs = *tevs;
1288 tf.ntevs = 0;
1289
1290 ret = debuginfo__find_probes(dbg, &tf.pf);
1291 if (ret < 0) {
1292 for (i = 0; i < tf.ntevs; i++)
1293 clear_probe_trace_event(&tf.tevs[i]);
1294 zfree(tevs);
1295 return ret;
1296 }
1297
1298 return (ret < 0) ? ret : tf.ntevs;
1299 }
1300
1301 /* Collect available variables in this scope */
1302 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1303 {
1304 struct available_var_finder *af = data;
1305 struct variable_list *vl;
1306 struct strbuf buf = STRBUF_INIT;
1307 int tag, ret;
1308
1309 vl = &af->vls[af->nvls - 1];
1310
1311 tag = dwarf_tag(die_mem);
1312 if (tag == DW_TAG_formal_parameter ||
1313 tag == DW_TAG_variable) {
1314 ret = convert_variable_location(die_mem, af->pf.addr,
1315 af->pf.fb_ops, &af->pf.sp_die,
1316 NULL);
1317 if (ret == 0 || ret == -ERANGE) {
1318 int ret2;
1319 bool externs = !af->child;
1320
1321 if (strbuf_init(&buf, 64) < 0)
1322 goto error;
1323
1324 if (probe_conf.show_location_range) {
1325 if (!externs)
1326 ret2 = strbuf_add(&buf,
1327 ret ? "[INV]\t" : "[VAL]\t", 6);
1328 else
1329 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1330 if (ret2)
1331 goto error;
1332 }
1333
1334 ret2 = die_get_varname(die_mem, &buf);
1335
1336 if (!ret2 && probe_conf.show_location_range &&
1337 !externs) {
1338 if (strbuf_addch(&buf, '\t') < 0)
1339 goto error;
1340 ret2 = die_get_var_range(&af->pf.sp_die,
1341 die_mem, &buf);
1342 }
1343
1344 pr_debug("Add new var: %s\n", buf.buf);
1345 if (ret2 == 0) {
1346 strlist__add(vl->vars,
1347 strbuf_detach(&buf, NULL));
1348 }
1349 strbuf_release(&buf);
1350 }
1351 }
1352
1353 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1354 return DIE_FIND_CB_CONTINUE;
1355 else
1356 return DIE_FIND_CB_SIBLING;
1357 error:
1358 strbuf_release(&buf);
1359 pr_debug("Error in strbuf\n");
1360 return DIE_FIND_CB_END;
1361 }
1362
1363 /* Add a found vars into available variables list */
1364 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1365 {
1366 struct available_var_finder *af =
1367 container_of(pf, struct available_var_finder, pf);
1368 struct perf_probe_point *pp = &pf->pev->point;
1369 struct variable_list *vl;
1370 Dwarf_Die die_mem;
1371 int ret;
1372
1373 /* Check number of tevs */
1374 if (af->nvls == af->max_vls) {
1375 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1376 return -ERANGE;
1377 }
1378 vl = &af->vls[af->nvls++];
1379
1380 /* Trace point should be converted from subprogram DIE */
1381 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1382 pp->retprobe, pp->function, &vl->point);
1383 if (ret < 0)
1384 return ret;
1385
1386 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1387 vl->point.offset);
1388
1389 /* Find local variables */
1390 vl->vars = strlist__new(NULL, NULL);
1391 if (vl->vars == NULL)
1392 return -ENOMEM;
1393 af->child = true;
1394 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1395
1396 /* Find external variables */
1397 if (!probe_conf.show_ext_vars)
1398 goto out;
1399 /* Don't need to search child DIE for external vars. */
1400 af->child = false;
1401 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1402
1403 out:
1404 if (strlist__empty(vl->vars)) {
1405 strlist__delete(vl->vars);
1406 vl->vars = NULL;
1407 }
1408
1409 return ret;
1410 }
1411
1412 /*
1413 * Find available variables at given probe point
1414 * Return the number of found probe points. Return 0 if there is no
1415 * matched probe point. Return <0 if an error occurs.
1416 */
1417 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1418 struct perf_probe_event *pev,
1419 struct variable_list **vls)
1420 {
1421 struct available_var_finder af = {
1422 .pf = {.pev = pev, .callback = add_available_vars},
1423 .mod = dbg->mod,
1424 .max_vls = probe_conf.max_probes};
1425 int ret;
1426
1427 /* Allocate result vls array */
1428 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1429 if (*vls == NULL)
1430 return -ENOMEM;
1431
1432 af.vls = *vls;
1433 af.nvls = 0;
1434
1435 ret = debuginfo__find_probes(dbg, &af.pf);
1436 if (ret < 0) {
1437 /* Free vlist for error */
1438 while (af.nvls--) {
1439 zfree(&af.vls[af.nvls].point.symbol);
1440 strlist__delete(af.vls[af.nvls].vars);
1441 }
1442 zfree(vls);
1443 return ret;
1444 }
1445
1446 return (ret < 0) ? ret : af.nvls;
1447 }
1448
1449 /* For the kernel module, we need a special code to get a DIE */
1450 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1451 {
1452 int n, i;
1453 Elf32_Word shndx;
1454 Elf_Scn *scn;
1455 Elf *elf;
1456 GElf_Shdr mem, *shdr;
1457 const char *p;
1458
1459 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1460 if (!elf)
1461 return -EINVAL;
1462
1463 /* Get the number of relocations */
1464 n = dwfl_module_relocations(dbg->mod);
1465 if (n < 0)
1466 return -ENOENT;
1467 /* Search the relocation related .text section */
1468 for (i = 0; i < n; i++) {
1469 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1470 if (strcmp(p, ".text") == 0) {
1471 /* OK, get the section header */
1472 scn = elf_getscn(elf, shndx);
1473 if (!scn)
1474 return -ENOENT;
1475 shdr = gelf_getshdr(scn, &mem);
1476 if (!shdr)
1477 return -ENOENT;
1478 *offs = shdr->sh_addr;
1479 }
1480 }
1481 return 0;
1482 }
1483
1484 /* Reverse search */
1485 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1486 struct perf_probe_point *ppt)
1487 {
1488 Dwarf_Die cudie, spdie, indie;
1489 Dwarf_Addr _addr = 0, baseaddr = 0;
1490 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1491 int baseline = 0, lineno = 0, ret = 0;
1492 bool reloc = false;
1493
1494 retry:
1495 /* Find cu die */
1496 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1497 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1498 addr += baseaddr;
1499 reloc = true;
1500 goto retry;
1501 }
1502 pr_warning("Failed to find debug information for address %lx\n",
1503 addr);
1504 ret = -EINVAL;
1505 goto end;
1506 }
1507
1508 /* Find a corresponding line (filename and lineno) */
1509 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1510 /* Don't care whether it failed or not */
1511
1512 /* Find a corresponding function (name, baseline and baseaddr) */
1513 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1514 /* Get function entry information */
1515 func = basefunc = dwarf_diename(&spdie);
1516 if (!func ||
1517 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1518 dwarf_decl_line(&spdie, &baseline) != 0) {
1519 lineno = 0;
1520 goto post;
1521 }
1522
1523 fname = dwarf_decl_file(&spdie);
1524 if (addr == (unsigned long)baseaddr) {
1525 /* Function entry - Relative line number is 0 */
1526 lineno = baseline;
1527 goto post;
1528 }
1529
1530 /* Track down the inline functions step by step */
1531 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1532 &indie)) {
1533 /* There is an inline function */
1534 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1535 _addr == addr) {
1536 /*
1537 * addr is at an inline function entry.
1538 * In this case, lineno should be the call-site
1539 * line number. (overwrite lineinfo)
1540 */
1541 lineno = die_get_call_lineno(&indie);
1542 fname = die_get_call_file(&indie);
1543 break;
1544 } else {
1545 /*
1546 * addr is in an inline function body.
1547 * Since lineno points one of the lines
1548 * of the inline function, baseline should
1549 * be the entry line of the inline function.
1550 */
1551 tmp = dwarf_diename(&indie);
1552 if (!tmp ||
1553 dwarf_decl_line(&indie, &baseline) != 0)
1554 break;
1555 func = tmp;
1556 spdie = indie;
1557 }
1558 }
1559 /* Verify the lineno and baseline are in a same file */
1560 tmp = dwarf_decl_file(&spdie);
1561 if (!tmp || strcmp(tmp, fname) != 0)
1562 lineno = 0;
1563 }
1564
1565 post:
1566 /* Make a relative line number or an offset */
1567 if (lineno)
1568 ppt->line = lineno - baseline;
1569 else if (basefunc) {
1570 ppt->offset = addr - (unsigned long)baseaddr;
1571 func = basefunc;
1572 }
1573
1574 /* Duplicate strings */
1575 if (func) {
1576 ppt->function = strdup(func);
1577 if (ppt->function == NULL) {
1578 ret = -ENOMEM;
1579 goto end;
1580 }
1581 }
1582 if (fname) {
1583 ppt->file = strdup(fname);
1584 if (ppt->file == NULL) {
1585 zfree(&ppt->function);
1586 ret = -ENOMEM;
1587 goto end;
1588 }
1589 }
1590 end:
1591 if (ret == 0 && (fname || func))
1592 ret = 1; /* Found a point */
1593 return ret;
1594 }
1595
1596 /* Add a line and store the src path */
1597 static int line_range_add_line(const char *src, unsigned int lineno,
1598 struct line_range *lr)
1599 {
1600 /* Copy source path */
1601 if (!lr->path) {
1602 lr->path = strdup(src);
1603 if (lr->path == NULL)
1604 return -ENOMEM;
1605 }
1606 return intlist__add(lr->line_list, lineno);
1607 }
1608
1609 static int line_range_walk_cb(const char *fname, int lineno,
1610 Dwarf_Addr addr __maybe_unused,
1611 void *data)
1612 {
1613 struct line_finder *lf = data;
1614 int err;
1615
1616 if ((strtailcmp(fname, lf->fname) != 0) ||
1617 (lf->lno_s > lineno || lf->lno_e < lineno))
1618 return 0;
1619
1620 err = line_range_add_line(fname, lineno, lf->lr);
1621 if (err < 0 && err != -EEXIST)
1622 return err;
1623
1624 return 0;
1625 }
1626
1627 /* Find line range from its line number */
1628 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1629 {
1630 int ret;
1631
1632 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1633
1634 /* Update status */
1635 if (ret >= 0)
1636 if (!intlist__empty(lf->lr->line_list))
1637 ret = lf->found = 1;
1638 else
1639 ret = 0; /* Lines are not found */
1640 else {
1641 zfree(&lf->lr->path);
1642 }
1643 return ret;
1644 }
1645
1646 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1647 {
1648 int ret = find_line_range_by_line(in_die, data);
1649
1650 /*
1651 * We have to check all instances of inlined function, because
1652 * some execution paths can be optimized out depends on the
1653 * function argument of instances. However, if an error occurs,
1654 * it should be handled by the caller.
1655 */
1656 return ret < 0 ? ret : 0;
1657 }
1658
1659 /* Search function definition from function name */
1660 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1661 {
1662 struct dwarf_callback_param *param = data;
1663 struct line_finder *lf = param->data;
1664 struct line_range *lr = lf->lr;
1665
1666 /* Check declared file */
1667 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1668 return DWARF_CB_OK;
1669
1670 if (die_is_func_def(sp_die) &&
1671 die_match_name(sp_die, lr->function)) {
1672 lf->fname = dwarf_decl_file(sp_die);
1673 dwarf_decl_line(sp_die, &lr->offset);
1674 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1675 lf->lno_s = lr->offset + lr->start;
1676 if (lf->lno_s < 0) /* Overflow */
1677 lf->lno_s = INT_MAX;
1678 lf->lno_e = lr->offset + lr->end;
1679 if (lf->lno_e < 0) /* Overflow */
1680 lf->lno_e = INT_MAX;
1681 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1682 lr->start = lf->lno_s;
1683 lr->end = lf->lno_e;
1684 if (!die_is_func_instance(sp_die))
1685 param->retval = die_walk_instances(sp_die,
1686 line_range_inline_cb, lf);
1687 else
1688 param->retval = find_line_range_by_line(sp_die, lf);
1689 return DWARF_CB_ABORT;
1690 }
1691 return DWARF_CB_OK;
1692 }
1693
1694 static int find_line_range_by_func(struct line_finder *lf)
1695 {
1696 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1697 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1698 return param.retval;
1699 }
1700
1701 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1702 {
1703 struct line_finder lf = {.lr = lr, .found = 0};
1704 int ret = 0;
1705 Dwarf_Off off = 0, noff;
1706 size_t cuhl;
1707 Dwarf_Die *diep;
1708 const char *comp_dir;
1709
1710 /* Fastpath: lookup by function name from .debug_pubnames section */
1711 if (lr->function) {
1712 struct pubname_callback_param pubname_param = {
1713 .function = lr->function, .file = lr->file,
1714 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1715 struct dwarf_callback_param line_range_param = {
1716 .data = (void *)&lf, .retval = 0};
1717
1718 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1719 &pubname_param, 0);
1720 if (pubname_param.found) {
1721 line_range_search_cb(&lf.sp_die, &line_range_param);
1722 if (lf.found)
1723 goto found;
1724 }
1725 }
1726
1727 /* Loop on CUs (Compilation Unit) */
1728 while (!lf.found && ret >= 0) {
1729 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1730 NULL, NULL, NULL) != 0)
1731 break;
1732
1733 /* Get the DIE(Debugging Information Entry) of this CU */
1734 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1735 if (!diep)
1736 continue;
1737
1738 /* Check if target file is included. */
1739 if (lr->file)
1740 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1741 else
1742 lf.fname = 0;
1743
1744 if (!lr->file || lf.fname) {
1745 if (lr->function)
1746 ret = find_line_range_by_func(&lf);
1747 else {
1748 lf.lno_s = lr->start;
1749 lf.lno_e = lr->end;
1750 ret = find_line_range_by_line(NULL, &lf);
1751 }
1752 }
1753 off = noff;
1754 }
1755
1756 found:
1757 /* Store comp_dir */
1758 if (lf.found) {
1759 comp_dir = cu_get_comp_dir(&lf.cu_die);
1760 if (comp_dir) {
1761 lr->comp_dir = strdup(comp_dir);
1762 if (!lr->comp_dir)
1763 ret = -ENOMEM;
1764 }
1765 }
1766
1767 pr_debug("path: %s\n", lr->path);
1768 return (ret < 0) ? ret : lf.found;
1769 }
1770
1771 /*
1772 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1773 * and chop off leading directories that do not exist. Result is passed back as
1774 * a newly allocated path on success.
1775 * Return 0 if file was found and readable, -errno otherwise.
1776 */
1777 int get_real_path(const char *raw_path, const char *comp_dir,
1778 char **new_path)
1779 {
1780 const char *prefix = symbol_conf.source_prefix;
1781
1782 if (!prefix) {
1783 if (raw_path[0] != '/' && comp_dir)
1784 /* If not an absolute path, try to use comp_dir */
1785 prefix = comp_dir;
1786 else {
1787 if (access(raw_path, R_OK) == 0) {
1788 *new_path = strdup(raw_path);
1789 return *new_path ? 0 : -ENOMEM;
1790 } else
1791 return -errno;
1792 }
1793 }
1794
1795 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1796 if (!*new_path)
1797 return -ENOMEM;
1798
1799 for (;;) {
1800 sprintf(*new_path, "%s/%s", prefix, raw_path);
1801
1802 if (access(*new_path, R_OK) == 0)
1803 return 0;
1804
1805 if (!symbol_conf.source_prefix) {
1806 /* In case of searching comp_dir, don't retry */
1807 zfree(new_path);
1808 return -errno;
1809 }
1810
1811 switch (errno) {
1812 case ENAMETOOLONG:
1813 case ENOENT:
1814 case EROFS:
1815 case EFAULT:
1816 raw_path = strchr(++raw_path, '/');
1817 if (!raw_path) {
1818 zfree(new_path);
1819 return -ENOENT;
1820 }
1821 continue;
1822
1823 default:
1824 zfree(new_path);
1825 return -errno;
1826 }
1827 }
1828 }
Linux with added FPC-III support