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Linux 5.1.15
[linux/fpc-iii.git] / tools / perf / util / probe-finder.c
blobc37fbef1711dd70df81d6b0d82556121fa4a1bc1
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 <inttypes.h>
23 #include <sys/utsname.h>
24 #include <sys/types.h>
25 #include <sys/stat.h>
26 #include <fcntl.h>
27 #include <errno.h>
28 #include <stdio.h>
29 #include <unistd.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <stdarg.h>
33 #include <dwarf-regs.h>
34
35 #include <linux/bitops.h>
36 #include "event.h"
37 #include "dso.h"
38 #include "debug.h"
39 #include "intlist.h"
40 #include "util.h"
41 #include "strlist.h"
42 #include "symbol.h"
43 #include "probe-finder.h"
44 #include "probe-file.h"
45 #include "string2.h"
46
47 /* Kprobe tracer basic type is up to u64 */
48 #define MAX_BASIC_TYPE_BITS 64
49
50 /* Dwarf FL wrappers */
51 static char *debuginfo_path; /* Currently dummy */
52
53 static const Dwfl_Callbacks offline_callbacks = {
54 .find_debuginfo = dwfl_standard_find_debuginfo,
55 .debuginfo_path = &debuginfo_path,
56
57 .section_address = dwfl_offline_section_address,
58
59 /* We use this table for core files too. */
60 .find_elf = dwfl_build_id_find_elf,
61 };
62
63 /* Get a Dwarf from offline image */
64 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
65 const char *path)
66 {
67 int fd;
68
69 fd = open(path, O_RDONLY);
70 if (fd < 0)
71 return fd;
72
73 dbg->dwfl = dwfl_begin(&offline_callbacks);
74 if (!dbg->dwfl)
75 goto error;
76
77 dwfl_report_begin(dbg->dwfl);
78 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
79 if (!dbg->mod)
80 goto error;
81
82 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
83 if (!dbg->dbg)
84 goto error;
85
86 dwfl_report_end(dbg->dwfl, NULL, NULL);
87
88 return 0;
89 error:
90 if (dbg->dwfl)
91 dwfl_end(dbg->dwfl);
92 else
93 close(fd);
94 memset(dbg, 0, sizeof(*dbg));
95
96 return -ENOENT;
97 }
98
99 static struct debuginfo *__debuginfo__new(const char *path)
100 {
101 struct debuginfo *dbg = zalloc(sizeof(*dbg));
102 if (!dbg)
103 return NULL;
104
105 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
106 zfree(&dbg);
107 if (dbg)
108 pr_debug("Open Debuginfo file: %s\n", path);
109 return dbg;
110 }
111
112 enum dso_binary_type distro_dwarf_types[] = {
113 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
114 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
115 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
116 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
117 DSO_BINARY_TYPE__NOT_FOUND,
118 };
119
120 struct debuginfo *debuginfo__new(const char *path)
121 {
122 enum dso_binary_type *type;
123 char buf[PATH_MAX], nil = '\0';
124 struct dso *dso;
125 struct debuginfo *dinfo = NULL;
126
127 /* Try to open distro debuginfo files */
128 dso = dso__new(path);
129 if (!dso)
130 goto out;
131
132 for (type = distro_dwarf_types;
133 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
134 type++) {
135 if (dso__read_binary_type_filename(dso, *type, &nil,
136 buf, PATH_MAX) < 0)
137 continue;
138 dinfo = __debuginfo__new(buf);
139 }
140 dso__put(dso);
141
142 out:
143 /* if failed to open all distro debuginfo, open given binary */
144 return dinfo ? : __debuginfo__new(path);
145 }
146
147 void debuginfo__delete(struct debuginfo *dbg)
148 {
149 if (dbg) {
150 if (dbg->dwfl)
151 dwfl_end(dbg->dwfl);
152 free(dbg);
153 }
154 }
155
156 /*
157 * Probe finder related functions
158 */
159
160 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
161 {
162 struct probe_trace_arg_ref *ref;
163 ref = zalloc(sizeof(struct probe_trace_arg_ref));
164 if (ref != NULL)
165 ref->offset = offs;
166 return ref;
167 }
168
169 /*
170 * Convert a location into trace_arg.
171 * If tvar == NULL, this just checks variable can be converted.
172 * If fentry == true and vr_die is a parameter, do huristic search
173 * for the location fuzzed by function entry mcount.
174 */
175 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
176 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
177 unsigned int machine,
178 struct probe_trace_arg *tvar)
179 {
180 Dwarf_Attribute attr;
181 Dwarf_Addr tmp = 0;
182 Dwarf_Op *op;
183 size_t nops;
184 unsigned int regn;
185 Dwarf_Word offs = 0;
186 bool ref = false;
187 const char *regs;
188 int ret, ret2 = 0;
189
190 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
191 goto static_var;
192
193 /* TODO: handle more than 1 exprs */
194 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
195 return -EINVAL; /* Broken DIE ? */
196 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
197 ret = dwarf_entrypc(sp_die, &tmp);
198 if (ret)
199 return -ENOENT;
200
201 if (probe_conf.show_location_range &&
202 (dwarf_tag(vr_die) == DW_TAG_variable)) {
203 ret2 = -ERANGE;
204 } else if (addr != tmp ||
205 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
206 return -ENOENT;
207 }
208
209 ret = dwarf_highpc(sp_die, &tmp);
210 if (ret)
211 return -ENOENT;
212 /*
213 * This is fuzzed by fentry mcount. We try to find the
214 * parameter location at the earliest address.
215 */
216 for (addr += 1; addr <= tmp; addr++) {
217 if (dwarf_getlocation_addr(&attr, addr, &op,
218 &nops, 1) > 0)
219 goto found;
220 }
221 return -ENOENT;
222 }
223 found:
224 if (nops == 0)
225 /* TODO: Support const_value */
226 return -ENOENT;
227
228 if (op->atom == DW_OP_addr) {
229 static_var:
230 if (!tvar)
231 return ret2;
232 /* Static variables on memory (not stack), make @varname */
233 ret = strlen(dwarf_diename(vr_die));
234 tvar->value = zalloc(ret + 2);
235 if (tvar->value == NULL)
236 return -ENOMEM;
237 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
238 tvar->ref = alloc_trace_arg_ref((long)offs);
239 if (tvar->ref == NULL)
240 return -ENOMEM;
241 return ret2;
242 }
243
244 /* If this is based on frame buffer, set the offset */
245 if (op->atom == DW_OP_fbreg) {
246 if (fb_ops == NULL)
247 return -ENOTSUP;
248 ref = true;
249 offs = op->number;
250 op = &fb_ops[0];
251 }
252
253 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
254 regn = op->atom - DW_OP_breg0;
255 offs += op->number;
256 ref = true;
257 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
258 regn = op->atom - DW_OP_reg0;
259 } else if (op->atom == DW_OP_bregx) {
260 regn = op->number;
261 offs += op->number2;
262 ref = true;
263 } else if (op->atom == DW_OP_regx) {
264 regn = op->number;
265 } else {
266 pr_debug("DW_OP %x is not supported.\n", op->atom);
267 return -ENOTSUP;
268 }
269
270 if (!tvar)
271 return ret2;
272
273 regs = get_dwarf_regstr(regn, machine);
274 if (!regs) {
275 /* This should be a bug in DWARF or this tool */
276 pr_warning("Mapping for the register number %u "
277 "missing on this architecture.\n", regn);
278 return -ENOTSUP;
279 }
280
281 tvar->value = strdup(regs);
282 if (tvar->value == NULL)
283 return -ENOMEM;
284
285 if (ref) {
286 tvar->ref = alloc_trace_arg_ref((long)offs);
287 if (tvar->ref == NULL)
288 return -ENOMEM;
289 }
290 return ret2;
291 }
292
293 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
294
295 static int convert_variable_type(Dwarf_Die *vr_die,
296 struct probe_trace_arg *tvar,
297 const char *cast)
298 {
299 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
300 Dwarf_Die type;
301 char buf[16];
302 char sbuf[STRERR_BUFSIZE];
303 int bsize, boffs, total;
304 int ret;
305 char prefix;
306
307 /* TODO: check all types */
308 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
309 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
310 /* Non string type is OK */
311 /* and respect signedness/hexadecimal cast */
312 tvar->type = strdup(cast);
313 return (tvar->type == NULL) ? -ENOMEM : 0;
314 }
315
316 bsize = dwarf_bitsize(vr_die);
317 if (bsize > 0) {
318 /* This is a bitfield */
319 boffs = dwarf_bitoffset(vr_die);
320 total = dwarf_bytesize(vr_die);
321 if (boffs < 0 || total < 0)
322 return -ENOENT;
323 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
324 BYTES_TO_BITS(total));
325 goto formatted;
326 }
327
328 if (die_get_real_type(vr_die, &type) == NULL) {
329 pr_warning("Failed to get a type information of %s.\n",
330 dwarf_diename(vr_die));
331 return -ENOENT;
332 }
333
334 pr_debug("%s type is %s.\n",
335 dwarf_diename(vr_die), dwarf_diename(&type));
336
337 if (cast && strcmp(cast, "string") == 0) { /* String type */
338 ret = dwarf_tag(&type);
339 if (ret != DW_TAG_pointer_type &&
340 ret != DW_TAG_array_type) {
341 pr_warning("Failed to cast into string: "
342 "%s(%s) is not a pointer nor array.\n",
343 dwarf_diename(vr_die), dwarf_diename(&type));
344 return -EINVAL;
345 }
346 if (die_get_real_type(&type, &type) == NULL) {
347 pr_warning("Failed to get a type"
348 " information.\n");
349 return -ENOENT;
350 }
351 if (ret == DW_TAG_pointer_type) {
352 while (*ref_ptr)
353 ref_ptr = &(*ref_ptr)->next;
354 /* Add new reference with offset +0 */
355 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
356 if (*ref_ptr == NULL) {
357 pr_warning("Out of memory error\n");
358 return -ENOMEM;
359 }
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)
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 goto next;
452 } else if (tag == DW_TAG_pointer_type) {
453 /* Check the pointer and dereference */
454 if (!field->ref) {
455 pr_err("Semantic error: %s must be referred by '->'\n",
456 field->name);
457 return -EINVAL;
458 }
459 /* Get the type pointed by this pointer */
460 if (die_get_real_type(&type, &type) == NULL) {
461 pr_warning("Failed to get the type of %s.\n", varname);
462 return -ENOENT;
463 }
464 /* Verify it is a data structure */
465 tag = dwarf_tag(&type);
466 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
467 pr_warning("%s is not a data structure nor a union.\n",
468 varname);
469 return -EINVAL;
470 }
471
472 ref = zalloc(sizeof(struct probe_trace_arg_ref));
473 if (ref == NULL)
474 return -ENOMEM;
475 if (*ref_ptr)
476 (*ref_ptr)->next = ref;
477 else
478 *ref_ptr = ref;
479 } else {
480 /* Verify it is a data structure */
481 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
482 pr_warning("%s is not a data structure nor a union.\n",
483 varname);
484 return -EINVAL;
485 }
486 if (field->name[0] == '[') {
487 pr_err("Semantic error: %s is not a pointer"
488 " nor array.\n", varname);
489 return -EINVAL;
490 }
491 /* While prcessing unnamed field, we don't care about this */
492 if (field->ref && dwarf_diename(vr_die)) {
493 pr_err("Semantic error: %s must be referred by '.'\n",
494 field->name);
495 return -EINVAL;
496 }
497 if (!ref) {
498 pr_warning("Structure on a register is not "
499 "supported yet.\n");
500 return -ENOTSUP;
501 }
502 }
503
504 if (die_find_member(&type, field->name, die_mem) == NULL) {
505 pr_warning("%s(type:%s) has no member %s.\n", varname,
506 dwarf_diename(&type), field->name);
507 return -EINVAL;
508 }
509
510 /* Get the offset of the field */
511 if (tag == DW_TAG_union_type) {
512 offs = 0;
513 } else {
514 ret = die_get_data_member_location(die_mem, &offs);
515 if (ret < 0) {
516 pr_warning("Failed to get the offset of %s.\n",
517 field->name);
518 return ret;
519 }
520 }
521 ref->offset += (long)offs;
522
523 /* If this member is unnamed, we need to reuse this field */
524 if (!dwarf_diename(die_mem))
525 return convert_variable_fields(die_mem, varname, field,
526 &ref, die_mem);
527
528 next:
529 /* Converting next field */
530 if (field->next)
531 return convert_variable_fields(die_mem, field->name,
532 field->next, &ref, die_mem);
533 else
534 return 0;
535 }
536
537 /* Show a variables in kprobe event format */
538 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
539 {
540 Dwarf_Die die_mem;
541 int ret;
542
543 pr_debug("Converting variable %s into trace event.\n",
544 dwarf_diename(vr_die));
545
546 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
547 &pf->sp_die, pf->machine, pf->tvar);
548 if (ret == -ENOENT || ret == -EINVAL) {
549 pr_err("Failed to find the location of the '%s' variable at this address.\n"
550 " Perhaps it has been optimized out.\n"
551 " Use -V with the --range option to show '%s' location range.\n",
552 pf->pvar->var, pf->pvar->var);
553 } else if (ret == -ENOTSUP)
554 pr_err("Sorry, we don't support this variable location yet.\n");
555 else if (ret == 0 && pf->pvar->field) {
556 ret = convert_variable_fields(vr_die, pf->pvar->var,
557 pf->pvar->field, &pf->tvar->ref,
558 &die_mem);
559 vr_die = &die_mem;
560 }
561 if (ret == 0)
562 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
563 /* *expr will be cached in libdw. Don't free it. */
564 return ret;
565 }
566
567 /* Find a variable in a scope DIE */
568 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
569 {
570 Dwarf_Die vr_die;
571 char *buf, *ptr;
572 int ret = 0;
573
574 /* Copy raw parameters */
575 if (!is_c_varname(pf->pvar->var))
576 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
577
578 if (pf->pvar->name)
579 pf->tvar->name = strdup(pf->pvar->name);
580 else {
581 buf = synthesize_perf_probe_arg(pf->pvar);
582 if (!buf)
583 return -ENOMEM;
584 ptr = strchr(buf, ':'); /* Change type separator to _ */
585 if (ptr)
586 *ptr = '_';
587 pf->tvar->name = buf;
588 }
589 if (pf->tvar->name == NULL)
590 return -ENOMEM;
591
592 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
593 /* Search child die for local variables and parameters. */
594 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
595 /* Search again in global variables */
596 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
597 0, &vr_die)) {
598 pr_warning("Failed to find '%s' in this function.\n",
599 pf->pvar->var);
600 ret = -ENOENT;
601 }
602 }
603 if (ret >= 0)
604 ret = convert_variable(&vr_die, pf);
605
606 return ret;
607 }
608
609 /* Convert subprogram DIE to trace point */
610 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
611 Dwarf_Addr paddr, bool retprobe,
612 const char *function,
613 struct probe_trace_point *tp)
614 {
615 Dwarf_Addr eaddr, highaddr;
616 GElf_Sym sym;
617 const char *symbol;
618
619 /* Verify the address is correct */
620 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
621 pr_warning("Failed to get entry address of %s\n",
622 dwarf_diename(sp_die));
623 return -ENOENT;
624 }
625 if (dwarf_highpc(sp_die, &highaddr) != 0) {
626 pr_warning("Failed to get end address of %s\n",
627 dwarf_diename(sp_die));
628 return -ENOENT;
629 }
630 if (paddr > highaddr) {
631 pr_warning("Offset specified is greater than size of %s\n",
632 dwarf_diename(sp_die));
633 return -EINVAL;
634 }
635
636 symbol = dwarf_diename(sp_die);
637 if (!symbol) {
638 /* Try to get the symbol name from symtab */
639 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
640 if (!symbol) {
641 pr_warning("Failed to find symbol at 0x%lx\n",
642 (unsigned long)paddr);
643 return -ENOENT;
644 }
645 eaddr = sym.st_value;
646 }
647 tp->offset = (unsigned long)(paddr - eaddr);
648 tp->address = (unsigned long)paddr;
649 tp->symbol = strdup(symbol);
650 if (!tp->symbol)
651 return -ENOMEM;
652
653 /* Return probe must be on the head of a subprogram */
654 if (retprobe) {
655 if (eaddr != paddr) {
656 pr_warning("Failed to find \"%s%%return\",\n"
657 " because %s is an inlined function and"
658 " has no return point.\n", function,
659 function);
660 return -EINVAL;
661 }
662 tp->retprobe = true;
663 }
664
665 return 0;
666 }
667
668 /* Call probe_finder callback with scope DIE */
669 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
670 {
671 Dwarf_Attribute fb_attr;
672 Dwarf_Frame *frame = NULL;
673 size_t nops;
674 int ret;
675
676 if (!sc_die) {
677 pr_err("Caller must pass a scope DIE. Program error.\n");
678 return -EINVAL;
679 }
680
681 /* If not a real subprogram, find a real one */
682 if (!die_is_func_def(sc_die)) {
683 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
684 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
685 pr_warning("Ignoring tail call from %s\n",
686 dwarf_diename(&pf->sp_die));
687 return 0;
688 } else {
689 pr_warning("Failed to find probe point in any "
690 "functions.\n");
691 return -ENOENT;
692 }
693 }
694 } else
695 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
696
697 /* Get the frame base attribute/ops from subprogram */
698 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
699 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
700 if (ret <= 0 || nops == 0) {
701 pf->fb_ops = NULL;
702 #if _ELFUTILS_PREREQ(0, 142)
703 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
704 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
705 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
706 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
707 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
708 pr_warning("Failed to get call frame on 0x%jx\n",
709 (uintmax_t)pf->addr);
710 free(frame);
711 return -ENOENT;
712 }
713 #endif
714 }
715
716 /* Call finder's callback handler */
717 ret = pf->callback(sc_die, pf);
718
719 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
720 free(frame);
721 pf->fb_ops = NULL;
722
723 return ret;
724 }
725
726 struct find_scope_param {
727 const char *function;
728 const char *file;
729 int line;
730 int diff;
731 Dwarf_Die *die_mem;
732 bool found;
733 };
734
735 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
736 {
737 struct find_scope_param *fsp = data;
738 const char *file;
739 int lno;
740
741 /* Skip if declared file name does not match */
742 if (fsp->file) {
743 file = dwarf_decl_file(fn_die);
744 if (!file || strcmp(fsp->file, file) != 0)
745 return 0;
746 }
747 /* If the function name is given, that's what user expects */
748 if (fsp->function) {
749 if (die_match_name(fn_die, fsp->function)) {
750 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
751 fsp->found = true;
752 return 1;
753 }
754 } else {
755 /* With the line number, find the nearest declared DIE */
756 dwarf_decl_line(fn_die, &lno);
757 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
758 /* Keep a candidate and continue */
759 fsp->diff = fsp->line - lno;
760 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
761 fsp->found = true;
762 }
763 }
764 return 0;
765 }
766
767 /* Find an appropriate scope fits to given conditions */
768 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
769 {
770 struct find_scope_param fsp = {
771 .function = pf->pev->point.function,
772 .file = pf->fname,
773 .line = pf->lno,
774 .diff = INT_MAX,
775 .die_mem = die_mem,
776 .found = false,
777 };
778
779 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
780
781 return fsp.found ? die_mem : NULL;
782 }
783
784 static int probe_point_line_walker(const char *fname, int lineno,
785 Dwarf_Addr addr, void *data)
786 {
787 struct probe_finder *pf = data;
788 Dwarf_Die *sc_die, die_mem;
789 int ret;
790
791 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
792 return 0;
793
794 pf->addr = addr;
795 sc_die = find_best_scope(pf, &die_mem);
796 if (!sc_die) {
797 pr_warning("Failed to find scope of probe point.\n");
798 return -ENOENT;
799 }
800
801 ret = call_probe_finder(sc_die, pf);
802
803 /* Continue if no error, because the line will be in inline function */
804 return ret < 0 ? ret : 0;
805 }
806
807 /* Find probe point from its line number */
808 static int find_probe_point_by_line(struct probe_finder *pf)
809 {
810 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
811 }
812
813 /* Find lines which match lazy pattern */
814 static int find_lazy_match_lines(struct intlist *list,
815 const char *fname, const char *pat)
816 {
817 FILE *fp;
818 char *line = NULL;
819 size_t line_len;
820 ssize_t len;
821 int count = 0, linenum = 1;
822 char sbuf[STRERR_BUFSIZE];
823
824 fp = fopen(fname, "r");
825 if (!fp) {
826 pr_warning("Failed to open %s: %s\n", fname,
827 str_error_r(errno, sbuf, sizeof(sbuf)));
828 return -errno;
829 }
830
831 while ((len = getline(&line, &line_len, fp)) > 0) {
832
833 if (line[len - 1] == '\n')
834 line[len - 1] = '\0';
835
836 if (strlazymatch(line, pat)) {
837 intlist__add(list, linenum);
838 count++;
839 }
840 linenum++;
841 }
842
843 if (ferror(fp))
844 count = -errno;
845 free(line);
846 fclose(fp);
847
848 if (count == 0)
849 pr_debug("No matched lines found in %s.\n", fname);
850 return count;
851 }
852
853 static int probe_point_lazy_walker(const char *fname, int lineno,
854 Dwarf_Addr addr, void *data)
855 {
856 struct probe_finder *pf = data;
857 Dwarf_Die *sc_die, die_mem;
858 int ret;
859
860 if (!intlist__has_entry(pf->lcache, lineno) ||
861 strtailcmp(fname, pf->fname) != 0)
862 return 0;
863
864 pr_debug("Probe line found: line:%d addr:0x%llx\n",
865 lineno, (unsigned long long)addr);
866 pf->addr = addr;
867 pf->lno = lineno;
868 sc_die = find_best_scope(pf, &die_mem);
869 if (!sc_die) {
870 pr_warning("Failed to find scope of probe point.\n");
871 return -ENOENT;
872 }
873
874 ret = call_probe_finder(sc_die, pf);
875
876 /*
877 * Continue if no error, because the lazy pattern will match
878 * to other lines
879 */
880 return ret < 0 ? ret : 0;
881 }
882
883 /* Find probe points from lazy pattern */
884 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
885 {
886 int ret = 0;
887 char *fpath;
888
889 if (intlist__empty(pf->lcache)) {
890 const char *comp_dir;
891
892 comp_dir = cu_get_comp_dir(&pf->cu_die);
893 ret = get_real_path(pf->fname, comp_dir, &fpath);
894 if (ret < 0) {
895 pr_warning("Failed to find source file path.\n");
896 return ret;
897 }
898
899 /* Matching lazy line pattern */
900 ret = find_lazy_match_lines(pf->lcache, fpath,
901 pf->pev->point.lazy_line);
902 free(fpath);
903 if (ret <= 0)
904 return ret;
905 }
906
907 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
908 }
909
910 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
911 {
912 struct perf_probe_point *pp = &pf->pev->point;
913
914 /* Not uprobe? */
915 if (!pf->pev->uprobes)
916 return;
917
918 /* Compiled with optimization? */
919 if (die_is_optimized_target(&pf->cu_die))
920 return;
921
922 /* Don't know entrypc? */
923 if (!pf->addr)
924 return;
925
926 /* Only FUNC and FUNC@SRC are eligible. */
927 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
928 pp->offset || pp->abs_address)
929 return;
930
931 /* Not interested in func parameter? */
932 if (!perf_probe_with_var(pf->pev))
933 return;
934
935 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
936 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
937 pf->addr);
938
939 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
940 }
941
942 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
943 {
944 struct probe_finder *pf = data;
945 struct perf_probe_point *pp = &pf->pev->point;
946 Dwarf_Addr addr;
947 int ret;
948
949 if (pp->lazy_line)
950 ret = find_probe_point_lazy(in_die, pf);
951 else {
952 /* Get probe address */
953 if (dwarf_entrypc(in_die, &addr) != 0) {
954 pr_warning("Failed to get entry address of %s.\n",
955 dwarf_diename(in_die));
956 return -ENOENT;
957 }
958 if (addr == 0) {
959 pr_debug("%s has no valid entry address. skipped.\n",
960 dwarf_diename(in_die));
961 return -ENOENT;
962 }
963 pf->addr = addr;
964 pf->addr += pp->offset;
965 pr_debug("found inline addr: 0x%jx\n",
966 (uintmax_t)pf->addr);
967
968 ret = call_probe_finder(in_die, pf);
969 }
970
971 return ret;
972 }
973
974 /* Callback parameter with return value for libdw */
975 struct dwarf_callback_param {
976 void *data;
977 int retval;
978 };
979
980 /* Search function from function name */
981 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
982 {
983 struct dwarf_callback_param *param = data;
984 struct probe_finder *pf = param->data;
985 struct perf_probe_point *pp = &pf->pev->point;
986
987 /* Check tag and diename */
988 if (!die_is_func_def(sp_die) ||
989 !die_match_name(sp_die, pp->function))
990 return DWARF_CB_OK;
991
992 /* Check declared file */
993 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
994 return DWARF_CB_OK;
995
996 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
997 (unsigned long)dwarf_dieoffset(sp_die));
998 pf->fname = dwarf_decl_file(sp_die);
999 if (pp->line) { /* Function relative line */
1000 dwarf_decl_line(sp_die, &pf->lno);
1001 pf->lno += pp->line;
1002 param->retval = find_probe_point_by_line(pf);
1003 } else if (die_is_func_instance(sp_die)) {
1004 /* Instances always have the entry address */
1005 dwarf_entrypc(sp_die, &pf->addr);
1006 /* But in some case the entry address is 0 */
1007 if (pf->addr == 0) {
1008 pr_debug("%s has no entry PC. Skipped\n",
1009 dwarf_diename(sp_die));
1010 param->retval = 0;
1011 /* Real function */
1012 } else if (pp->lazy_line)
1013 param->retval = find_probe_point_lazy(sp_die, pf);
1014 else {
1015 skip_prologue(sp_die, pf);
1016 pf->addr += pp->offset;
1017 /* TODO: Check the address in this function */
1018 param->retval = call_probe_finder(sp_die, pf);
1019 }
1020 } else if (!probe_conf.no_inlines) {
1021 /* Inlined function: search instances */
1022 param->retval = die_walk_instances(sp_die,
1023 probe_point_inline_cb, (void *)pf);
1024 /* This could be a non-existed inline definition */
1025 if (param->retval == -ENOENT)
1026 param->retval = 0;
1027 }
1028
1029 /* We need to find other candidates */
1030 if (strisglob(pp->function) && param->retval >= 0) {
1031 param->retval = 0; /* We have to clear the result */
1032 return DWARF_CB_OK;
1033 }
1034
1035 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1036 }
1037
1038 static int find_probe_point_by_func(struct probe_finder *pf)
1039 {
1040 struct dwarf_callback_param _param = {.data = (void *)pf,
1041 .retval = 0};
1042 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1043 return _param.retval;
1044 }
1045
1046 struct pubname_callback_param {
1047 char *function;
1048 char *file;
1049 Dwarf_Die *cu_die;
1050 Dwarf_Die *sp_die;
1051 int found;
1052 };
1053
1054 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1055 {
1056 struct pubname_callback_param *param = data;
1057
1058 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1059 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1060 return DWARF_CB_OK;
1061
1062 if (die_match_name(param->sp_die, param->function)) {
1063 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1064 return DWARF_CB_OK;
1065
1066 if (param->file &&
1067 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1068 return DWARF_CB_OK;
1069
1070 param->found = 1;
1071 return DWARF_CB_ABORT;
1072 }
1073 }
1074
1075 return DWARF_CB_OK;
1076 }
1077
1078 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1079 struct probe_finder *pf)
1080 {
1081 struct perf_probe_point *pp = &pf->pev->point;
1082 Dwarf_Off off, noff;
1083 size_t cuhl;
1084 Dwarf_Die *diep;
1085 int ret = 0;
1086
1087 off = 0;
1088 pf->lcache = intlist__new(NULL);
1089 if (!pf->lcache)
1090 return -ENOMEM;
1091
1092 /* Fastpath: lookup by function name from .debug_pubnames section */
1093 if (pp->function && !strisglob(pp->function)) {
1094 struct pubname_callback_param pubname_param = {
1095 .function = pp->function,
1096 .file = pp->file,
1097 .cu_die = &pf->cu_die,
1098 .sp_die = &pf->sp_die,
1099 .found = 0,
1100 };
1101 struct dwarf_callback_param probe_param = {
1102 .data = pf,
1103 };
1104
1105 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1106 &pubname_param, 0);
1107 if (pubname_param.found) {
1108 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1109 if (ret)
1110 goto found;
1111 }
1112 }
1113
1114 /* Loop on CUs (Compilation Unit) */
1115 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1116 /* Get the DIE(Debugging Information Entry) of this CU */
1117 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1118 if (!diep)
1119 continue;
1120
1121 /* Check if target file is included. */
1122 if (pp->file)
1123 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1124 else
1125 pf->fname = NULL;
1126
1127 if (!pp->file || pf->fname) {
1128 if (pp->function)
1129 ret = find_probe_point_by_func(pf);
1130 else if (pp->lazy_line)
1131 ret = find_probe_point_lazy(&pf->cu_die, pf);
1132 else {
1133 pf->lno = pp->line;
1134 ret = find_probe_point_by_line(pf);
1135 }
1136 if (ret < 0)
1137 break;
1138 }
1139 off = noff;
1140 }
1141
1142 found:
1143 intlist__delete(pf->lcache);
1144 pf->lcache = NULL;
1145
1146 return ret;
1147 }
1148
1149 /* Find probe points from debuginfo */
1150 static int debuginfo__find_probes(struct debuginfo *dbg,
1151 struct probe_finder *pf)
1152 {
1153 int ret = 0;
1154 Elf *elf;
1155 GElf_Ehdr ehdr;
1156
1157 if (pf->cfi_eh || pf->cfi_dbg)
1158 return debuginfo__find_probe_location(dbg, pf);
1159
1160 /* Get the call frame information from this dwarf */
1161 elf = dwarf_getelf(dbg->dbg);
1162 if (elf == NULL)
1163 return -EINVAL;
1164
1165 if (gelf_getehdr(elf, &ehdr) == NULL)
1166 return -EINVAL;
1167
1168 pf->machine = ehdr.e_machine;
1169
1170 #if _ELFUTILS_PREREQ(0, 142)
1171 do {
1172 GElf_Shdr shdr;
1173
1174 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1175 shdr.sh_type == SHT_PROGBITS)
1176 pf->cfi_eh = dwarf_getcfi_elf(elf);
1177
1178 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1179 } while (0);
1180 #endif
1181
1182 ret = debuginfo__find_probe_location(dbg, pf);
1183 return ret;
1184 }
1185
1186 struct local_vars_finder {
1187 struct probe_finder *pf;
1188 struct perf_probe_arg *args;
1189 bool vars;
1190 int max_args;
1191 int nargs;
1192 int ret;
1193 };
1194
1195 /* Collect available variables in this scope */
1196 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1197 {
1198 struct local_vars_finder *vf = data;
1199 struct probe_finder *pf = vf->pf;
1200 int tag;
1201
1202 tag = dwarf_tag(die_mem);
1203 if (tag == DW_TAG_formal_parameter ||
1204 (tag == DW_TAG_variable && vf->vars)) {
1205 if (convert_variable_location(die_mem, vf->pf->addr,
1206 vf->pf->fb_ops, &pf->sp_die,
1207 pf->machine, NULL) == 0) {
1208 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1209 if (vf->args[vf->nargs].var == NULL) {
1210 vf->ret = -ENOMEM;
1211 return DIE_FIND_CB_END;
1212 }
1213 pr_debug(" %s", vf->args[vf->nargs].var);
1214 vf->nargs++;
1215 }
1216 }
1217
1218 if (dwarf_haspc(die_mem, vf->pf->addr))
1219 return DIE_FIND_CB_CONTINUE;
1220 else
1221 return DIE_FIND_CB_SIBLING;
1222 }
1223
1224 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1225 struct perf_probe_arg *args)
1226 {
1227 Dwarf_Die die_mem;
1228 int i;
1229 int n = 0;
1230 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1231 .max_args = MAX_PROBE_ARGS, .ret = 0};
1232
1233 for (i = 0; i < pf->pev->nargs; i++) {
1234 /* var never be NULL */
1235 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1236 vf.vars = true;
1237 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1238 /* Copy normal argument */
1239 args[n] = pf->pev->args[i];
1240 n++;
1241 continue;
1242 }
1243 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1244 vf.nargs = n;
1245 /* Special local variables */
1246 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1247 &die_mem);
1248 pr_debug(" (%d)\n", vf.nargs - n);
1249 if (vf.ret < 0)
1250 return vf.ret;
1251 n = vf.nargs;
1252 }
1253 return n;
1254 }
1255
1256 /* Add a found probe point into trace event list */
1257 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1258 {
1259 struct trace_event_finder *tf =
1260 container_of(pf, struct trace_event_finder, pf);
1261 struct perf_probe_point *pp = &pf->pev->point;
1262 struct probe_trace_event *tev;
1263 struct perf_probe_arg *args = NULL;
1264 int ret, i;
1265
1266 /* Check number of tevs */
1267 if (tf->ntevs == tf->max_tevs) {
1268 pr_warning("Too many( > %d) probe point found.\n",
1269 tf->max_tevs);
1270 return -ERANGE;
1271 }
1272 tev = &tf->tevs[tf->ntevs++];
1273
1274 /* Trace point should be converted from subprogram DIE */
1275 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1276 pp->retprobe, pp->function, &tev->point);
1277 if (ret < 0)
1278 goto end;
1279
1280 tev->point.realname = strdup(dwarf_diename(sc_die));
1281 if (!tev->point.realname) {
1282 ret = -ENOMEM;
1283 goto end;
1284 }
1285
1286 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1287 tev->point.offset);
1288
1289 /* Expand special probe argument if exist */
1290 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1291 if (args == NULL) {
1292 ret = -ENOMEM;
1293 goto end;
1294 }
1295
1296 ret = expand_probe_args(sc_die, pf, args);
1297 if (ret < 0)
1298 goto end;
1299
1300 tev->nargs = ret;
1301 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1302 if (tev->args == NULL) {
1303 ret = -ENOMEM;
1304 goto end;
1305 }
1306
1307 /* Find each argument */
1308 for (i = 0; i < tev->nargs; i++) {
1309 pf->pvar = &args[i];
1310 pf->tvar = &tev->args[i];
1311 /* Variable should be found from scope DIE */
1312 ret = find_variable(sc_die, pf);
1313 if (ret != 0)
1314 break;
1315 }
1316
1317 end:
1318 if (ret) {
1319 clear_probe_trace_event(tev);
1320 tf->ntevs--;
1321 }
1322 free(args);
1323 return ret;
1324 }
1325
1326 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1327 int debuginfo__find_trace_events(struct debuginfo *dbg,
1328 struct perf_probe_event *pev,
1329 struct probe_trace_event **tevs)
1330 {
1331 struct trace_event_finder tf = {
1332 .pf = {.pev = pev, .callback = add_probe_trace_event},
1333 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1334 int ret, i;
1335
1336 /* Allocate result tevs array */
1337 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1338 if (*tevs == NULL)
1339 return -ENOMEM;
1340
1341 tf.tevs = *tevs;
1342 tf.ntevs = 0;
1343
1344 ret = debuginfo__find_probes(dbg, &tf.pf);
1345 if (ret < 0) {
1346 for (i = 0; i < tf.ntevs; i++)
1347 clear_probe_trace_event(&tf.tevs[i]);
1348 zfree(tevs);
1349 return ret;
1350 }
1351
1352 return (ret < 0) ? ret : tf.ntevs;
1353 }
1354
1355 /* Collect available variables in this scope */
1356 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1357 {
1358 struct available_var_finder *af = data;
1359 struct variable_list *vl;
1360 struct strbuf buf = STRBUF_INIT;
1361 int tag, ret;
1362
1363 vl = &af->vls[af->nvls - 1];
1364
1365 tag = dwarf_tag(die_mem);
1366 if (tag == DW_TAG_formal_parameter ||
1367 tag == DW_TAG_variable) {
1368 ret = convert_variable_location(die_mem, af->pf.addr,
1369 af->pf.fb_ops, &af->pf.sp_die,
1370 af->pf.machine, NULL);
1371 if (ret == 0 || ret == -ERANGE) {
1372 int ret2;
1373 bool externs = !af->child;
1374
1375 if (strbuf_init(&buf, 64) < 0)
1376 goto error;
1377
1378 if (probe_conf.show_location_range) {
1379 if (!externs)
1380 ret2 = strbuf_add(&buf,
1381 ret ? "[INV]\t" : "[VAL]\t", 6);
1382 else
1383 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1384 if (ret2)
1385 goto error;
1386 }
1387
1388 ret2 = die_get_varname(die_mem, &buf);
1389
1390 if (!ret2 && probe_conf.show_location_range &&
1391 !externs) {
1392 if (strbuf_addch(&buf, '\t') < 0)
1393 goto error;
1394 ret2 = die_get_var_range(&af->pf.sp_die,
1395 die_mem, &buf);
1396 }
1397
1398 pr_debug("Add new var: %s\n", buf.buf);
1399 if (ret2 == 0) {
1400 strlist__add(vl->vars,
1401 strbuf_detach(&buf, NULL));
1402 }
1403 strbuf_release(&buf);
1404 }
1405 }
1406
1407 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1408 return DIE_FIND_CB_CONTINUE;
1409 else
1410 return DIE_FIND_CB_SIBLING;
1411 error:
1412 strbuf_release(&buf);
1413 pr_debug("Error in strbuf\n");
1414 return DIE_FIND_CB_END;
1415 }
1416
1417 /* Add a found vars into available variables list */
1418 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1419 {
1420 struct available_var_finder *af =
1421 container_of(pf, struct available_var_finder, pf);
1422 struct perf_probe_point *pp = &pf->pev->point;
1423 struct variable_list *vl;
1424 Dwarf_Die die_mem;
1425 int ret;
1426
1427 /* Check number of tevs */
1428 if (af->nvls == af->max_vls) {
1429 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1430 return -ERANGE;
1431 }
1432 vl = &af->vls[af->nvls++];
1433
1434 /* Trace point should be converted from subprogram DIE */
1435 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1436 pp->retprobe, pp->function, &vl->point);
1437 if (ret < 0)
1438 return ret;
1439
1440 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1441 vl->point.offset);
1442
1443 /* Find local variables */
1444 vl->vars = strlist__new(NULL, NULL);
1445 if (vl->vars == NULL)
1446 return -ENOMEM;
1447 af->child = true;
1448 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1449
1450 /* Find external variables */
1451 if (!probe_conf.show_ext_vars)
1452 goto out;
1453 /* Don't need to search child DIE for external vars. */
1454 af->child = false;
1455 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1456
1457 out:
1458 if (strlist__empty(vl->vars)) {
1459 strlist__delete(vl->vars);
1460 vl->vars = NULL;
1461 }
1462
1463 return ret;
1464 }
1465
1466 /*
1467 * Find available variables at given probe point
1468 * Return the number of found probe points. Return 0 if there is no
1469 * matched probe point. Return <0 if an error occurs.
1470 */
1471 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1472 struct perf_probe_event *pev,
1473 struct variable_list **vls)
1474 {
1475 struct available_var_finder af = {
1476 .pf = {.pev = pev, .callback = add_available_vars},
1477 .mod = dbg->mod,
1478 .max_vls = probe_conf.max_probes};
1479 int ret;
1480
1481 /* Allocate result vls array */
1482 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1483 if (*vls == NULL)
1484 return -ENOMEM;
1485
1486 af.vls = *vls;
1487 af.nvls = 0;
1488
1489 ret = debuginfo__find_probes(dbg, &af.pf);
1490 if (ret < 0) {
1491 /* Free vlist for error */
1492 while (af.nvls--) {
1493 zfree(&af.vls[af.nvls].point.symbol);
1494 strlist__delete(af.vls[af.nvls].vars);
1495 }
1496 zfree(vls);
1497 return ret;
1498 }
1499
1500 return (ret < 0) ? ret : af.nvls;
1501 }
1502
1503 /* For the kernel module, we need a special code to get a DIE */
1504 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1505 bool adjust_offset)
1506 {
1507 int n, i;
1508 Elf32_Word shndx;
1509 Elf_Scn *scn;
1510 Elf *elf;
1511 GElf_Shdr mem, *shdr;
1512 const char *p;
1513
1514 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1515 if (!elf)
1516 return -EINVAL;
1517
1518 /* Get the number of relocations */
1519 n = dwfl_module_relocations(dbg->mod);
1520 if (n < 0)
1521 return -ENOENT;
1522 /* Search the relocation related .text section */
1523 for (i = 0; i < n; i++) {
1524 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1525 if (strcmp(p, ".text") == 0) {
1526 /* OK, get the section header */
1527 scn = elf_getscn(elf, shndx);
1528 if (!scn)
1529 return -ENOENT;
1530 shdr = gelf_getshdr(scn, &mem);
1531 if (!shdr)
1532 return -ENOENT;
1533 *offs = shdr->sh_addr;
1534 if (adjust_offset)
1535 *offs -= shdr->sh_offset;
1536 }
1537 }
1538 return 0;
1539 }
1540
1541 /* Reverse search */
1542 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1543 struct perf_probe_point *ppt)
1544 {
1545 Dwarf_Die cudie, spdie, indie;
1546 Dwarf_Addr _addr = 0, baseaddr = 0;
1547 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1548 int baseline = 0, lineno = 0, ret = 0;
1549
1550 /* We always need to relocate the address for aranges */
1551 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1552 addr += baseaddr;
1553 /* Find cu die */
1554 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1555 pr_warning("Failed to find debug information for address %lx\n",
1556 addr);
1557 ret = -EINVAL;
1558 goto end;
1559 }
1560
1561 /* Find a corresponding line (filename and lineno) */
1562 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1563 /* Don't care whether it failed or not */
1564
1565 /* Find a corresponding function (name, baseline and baseaddr) */
1566 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1567 /* Get function entry information */
1568 func = basefunc = dwarf_diename(&spdie);
1569 if (!func ||
1570 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1571 dwarf_decl_line(&spdie, &baseline) != 0) {
1572 lineno = 0;
1573 goto post;
1574 }
1575
1576 fname = dwarf_decl_file(&spdie);
1577 if (addr == (unsigned long)baseaddr) {
1578 /* Function entry - Relative line number is 0 */
1579 lineno = baseline;
1580 goto post;
1581 }
1582
1583 /* Track down the inline functions step by step */
1584 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1585 &indie)) {
1586 /* There is an inline function */
1587 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1588 _addr == addr) {
1589 /*
1590 * addr is at an inline function entry.
1591 * In this case, lineno should be the call-site
1592 * line number. (overwrite lineinfo)
1593 */
1594 lineno = die_get_call_lineno(&indie);
1595 fname = die_get_call_file(&indie);
1596 break;
1597 } else {
1598 /*
1599 * addr is in an inline function body.
1600 * Since lineno points one of the lines
1601 * of the inline function, baseline should
1602 * be the entry line of the inline function.
1603 */
1604 tmp = dwarf_diename(&indie);
1605 if (!tmp ||
1606 dwarf_decl_line(&indie, &baseline) != 0)
1607 break;
1608 func = tmp;
1609 spdie = indie;
1610 }
1611 }
1612 /* Verify the lineno and baseline are in a same file */
1613 tmp = dwarf_decl_file(&spdie);
1614 if (!tmp || strcmp(tmp, fname) != 0)
1615 lineno = 0;
1616 }
1617
1618 post:
1619 /* Make a relative line number or an offset */
1620 if (lineno)
1621 ppt->line = lineno - baseline;
1622 else if (basefunc) {
1623 ppt->offset = addr - (unsigned long)baseaddr;
1624 func = basefunc;
1625 }
1626
1627 /* Duplicate strings */
1628 if (func) {
1629 ppt->function = strdup(func);
1630 if (ppt->function == NULL) {
1631 ret = -ENOMEM;
1632 goto end;
1633 }
1634 }
1635 if (fname) {
1636 ppt->file = strdup(fname);
1637 if (ppt->file == NULL) {
1638 zfree(&ppt->function);
1639 ret = -ENOMEM;
1640 goto end;
1641 }
1642 }
1643 end:
1644 if (ret == 0 && (fname || func))
1645 ret = 1; /* Found a point */
1646 return ret;
1647 }
1648
1649 /* Add a line and store the src path */
1650 static int line_range_add_line(const char *src, unsigned int lineno,
1651 struct line_range *lr)
1652 {
1653 /* Copy source path */
1654 if (!lr->path) {
1655 lr->path = strdup(src);
1656 if (lr->path == NULL)
1657 return -ENOMEM;
1658 }
1659 return intlist__add(lr->line_list, lineno);
1660 }
1661
1662 static int line_range_walk_cb(const char *fname, int lineno,
1663 Dwarf_Addr addr __maybe_unused,
1664 void *data)
1665 {
1666 struct line_finder *lf = data;
1667 int err;
1668
1669 if ((strtailcmp(fname, lf->fname) != 0) ||
1670 (lf->lno_s > lineno || lf->lno_e < lineno))
1671 return 0;
1672
1673 err = line_range_add_line(fname, lineno, lf->lr);
1674 if (err < 0 && err != -EEXIST)
1675 return err;
1676
1677 return 0;
1678 }
1679
1680 /* Find line range from its line number */
1681 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1682 {
1683 int ret;
1684
1685 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1686
1687 /* Update status */
1688 if (ret >= 0)
1689 if (!intlist__empty(lf->lr->line_list))
1690 ret = lf->found = 1;
1691 else
1692 ret = 0; /* Lines are not found */
1693 else {
1694 zfree(&lf->lr->path);
1695 }
1696 return ret;
1697 }
1698
1699 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1700 {
1701 int ret = find_line_range_by_line(in_die, data);
1702
1703 /*
1704 * We have to check all instances of inlined function, because
1705 * some execution paths can be optimized out depends on the
1706 * function argument of instances. However, if an error occurs,
1707 * it should be handled by the caller.
1708 */
1709 return ret < 0 ? ret : 0;
1710 }
1711
1712 /* Search function definition from function name */
1713 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1714 {
1715 struct dwarf_callback_param *param = data;
1716 struct line_finder *lf = param->data;
1717 struct line_range *lr = lf->lr;
1718
1719 /* Check declared file */
1720 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1721 return DWARF_CB_OK;
1722
1723 if (die_is_func_def(sp_die) &&
1724 die_match_name(sp_die, lr->function)) {
1725 lf->fname = dwarf_decl_file(sp_die);
1726 dwarf_decl_line(sp_die, &lr->offset);
1727 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1728 lf->lno_s = lr->offset + lr->start;
1729 if (lf->lno_s < 0) /* Overflow */
1730 lf->lno_s = INT_MAX;
1731 lf->lno_e = lr->offset + lr->end;
1732 if (lf->lno_e < 0) /* Overflow */
1733 lf->lno_e = INT_MAX;
1734 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1735 lr->start = lf->lno_s;
1736 lr->end = lf->lno_e;
1737 if (!die_is_func_instance(sp_die))
1738 param->retval = die_walk_instances(sp_die,
1739 line_range_inline_cb, lf);
1740 else
1741 param->retval = find_line_range_by_line(sp_die, lf);
1742 return DWARF_CB_ABORT;
1743 }
1744 return DWARF_CB_OK;
1745 }
1746
1747 static int find_line_range_by_func(struct line_finder *lf)
1748 {
1749 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1750 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1751 return param.retval;
1752 }
1753
1754 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1755 {
1756 struct line_finder lf = {.lr = lr, .found = 0};
1757 int ret = 0;
1758 Dwarf_Off off = 0, noff;
1759 size_t cuhl;
1760 Dwarf_Die *diep;
1761 const char *comp_dir;
1762
1763 /* Fastpath: lookup by function name from .debug_pubnames section */
1764 if (lr->function) {
1765 struct pubname_callback_param pubname_param = {
1766 .function = lr->function, .file = lr->file,
1767 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1768 struct dwarf_callback_param line_range_param = {
1769 .data = (void *)&lf, .retval = 0};
1770
1771 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1772 &pubname_param, 0);
1773 if (pubname_param.found) {
1774 line_range_search_cb(&lf.sp_die, &line_range_param);
1775 if (lf.found)
1776 goto found;
1777 }
1778 }
1779
1780 /* Loop on CUs (Compilation Unit) */
1781 while (!lf.found && ret >= 0) {
1782 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1783 NULL, NULL, NULL) != 0)
1784 break;
1785
1786 /* Get the DIE(Debugging Information Entry) of this CU */
1787 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1788 if (!diep)
1789 continue;
1790
1791 /* Check if target file is included. */
1792 if (lr->file)
1793 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1794 else
1795 lf.fname = 0;
1796
1797 if (!lr->file || lf.fname) {
1798 if (lr->function)
1799 ret = find_line_range_by_func(&lf);
1800 else {
1801 lf.lno_s = lr->start;
1802 lf.lno_e = lr->end;
1803 ret = find_line_range_by_line(NULL, &lf);
1804 }
1805 }
1806 off = noff;
1807 }
1808
1809 found:
1810 /* Store comp_dir */
1811 if (lf.found) {
1812 comp_dir = cu_get_comp_dir(&lf.cu_die);
1813 if (comp_dir) {
1814 lr->comp_dir = strdup(comp_dir);
1815 if (!lr->comp_dir)
1816 ret = -ENOMEM;
1817 }
1818 }
1819
1820 pr_debug("path: %s\n", lr->path);
1821 return (ret < 0) ? ret : lf.found;
1822 }
1823
1824 /*
1825 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1826 * and chop off leading directories that do not exist. Result is passed back as
1827 * a newly allocated path on success.
1828 * Return 0 if file was found and readable, -errno otherwise.
1829 */
1830 int get_real_path(const char *raw_path, const char *comp_dir,
1831 char **new_path)
1832 {
1833 const char *prefix = symbol_conf.source_prefix;
1834
1835 if (!prefix) {
1836 if (raw_path[0] != '/' && comp_dir)
1837 /* If not an absolute path, try to use comp_dir */
1838 prefix = comp_dir;
1839 else {
1840 if (access(raw_path, R_OK) == 0) {
1841 *new_path = strdup(raw_path);
1842 return *new_path ? 0 : -ENOMEM;
1843 } else
1844 return -errno;
1845 }
1846 }
1847
1848 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1849 if (!*new_path)
1850 return -ENOMEM;
1851
1852 for (;;) {
1853 sprintf(*new_path, "%s/%s", prefix, raw_path);
1854
1855 if (access(*new_path, R_OK) == 0)
1856 return 0;
1857
1858 if (!symbol_conf.source_prefix) {
1859 /* In case of searching comp_dir, don't retry */
1860 zfree(new_path);
1861 return -errno;
1862 }
1863
1864 switch (errno) {
1865 case ENAMETOOLONG:
1866 case ENOENT:
1867 case EROFS:
1868 case EFAULT:
1869 raw_path = strchr(++raw_path, '/');
1870 if (!raw_path) {
1871 zfree(new_path);
1872 return -ENOENT;
1873 }
1874 continue;
1875
1876 default:
1877 zfree(new_path);
1878 return -errno;
1879 }
1880 }
1881 }
Linux with added FPC-III support