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Merge remote-tracking branch 'xen-tip/linux-next'
[deliverable/linux.git] / tools / perf / util / probe-finder.c
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 #include "probe-file.h"
43
44 /* Kprobe tracer basic type is up to u64 */
45 #define MAX_BASIC_TYPE_BITS 64
46
47 /* Dwarf FL wrappers */
48 static char *debuginfo_path; /* Currently dummy */
49
50 static const Dwfl_Callbacks offline_callbacks = {
51 .find_debuginfo = dwfl_standard_find_debuginfo,
52 .debuginfo_path = &debuginfo_path,
53
54 .section_address = dwfl_offline_section_address,
55
56 /* We use this table for core files too. */
57 .find_elf = dwfl_build_id_find_elf,
58 };
59
60 /* Get a Dwarf from offline image */
61 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
62 const char *path)
63 {
64 int fd;
65
66 fd = open(path, O_RDONLY);
67 if (fd < 0)
68 return fd;
69
70 dbg->dwfl = dwfl_begin(&offline_callbacks);
71 if (!dbg->dwfl)
72 goto error;
73
74 dwfl_report_begin(dbg->dwfl);
75 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
76 if (!dbg->mod)
77 goto error;
78
79 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
80 if (!dbg->dbg)
81 goto error;
82
83 dwfl_report_end(dbg->dwfl, NULL, NULL);
84
85 return 0;
86 error:
87 if (dbg->dwfl)
88 dwfl_end(dbg->dwfl);
89 else
90 close(fd);
91 memset(dbg, 0, sizeof(*dbg));
92
93 return -ENOENT;
94 }
95
96 static struct debuginfo *__debuginfo__new(const char *path)
97 {
98 struct debuginfo *dbg = zalloc(sizeof(*dbg));
99 if (!dbg)
100 return NULL;
101
102 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
103 zfree(&dbg);
104 if (dbg)
105 pr_debug("Open Debuginfo file: %s\n", path);
106 return dbg;
107 }
108
109 enum dso_binary_type distro_dwarf_types[] = {
110 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
111 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
112 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
113 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
114 DSO_BINARY_TYPE__NOT_FOUND,
115 };
116
117 struct debuginfo *debuginfo__new(const char *path)
118 {
119 enum dso_binary_type *type;
120 char buf[PATH_MAX], nil = '\0';
121 struct dso *dso;
122 struct debuginfo *dinfo = NULL;
123
124 /* Try to open distro debuginfo files */
125 dso = dso__new(path);
126 if (!dso)
127 goto out;
128
129 for (type = distro_dwarf_types;
130 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
131 type++) {
132 if (dso__read_binary_type_filename(dso, *type, &nil,
133 buf, PATH_MAX) < 0)
134 continue;
135 dinfo = __debuginfo__new(buf);
136 }
137 dso__put(dso);
138
139 out:
140 /* if failed to open all distro debuginfo, open given binary */
141 return dinfo ? : __debuginfo__new(path);
142 }
143
144 void debuginfo__delete(struct debuginfo *dbg)
145 {
146 if (dbg) {
147 if (dbg->dwfl)
148 dwfl_end(dbg->dwfl);
149 free(dbg);
150 }
151 }
152
153 /*
154 * Probe finder related functions
155 */
156
157 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
158 {
159 struct probe_trace_arg_ref *ref;
160 ref = zalloc(sizeof(struct probe_trace_arg_ref));
161 if (ref != NULL)
162 ref->offset = offs;
163 return ref;
164 }
165
166 /*
167 * Convert a location into trace_arg.
168 * If tvar == NULL, this just checks variable can be converted.
169 * If fentry == true and vr_die is a parameter, do huristic search
170 * for the location fuzzed by function entry mcount.
171 */
172 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
173 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
174 unsigned int machine,
175 struct probe_trace_arg *tvar)
176 {
177 Dwarf_Attribute attr;
178 Dwarf_Addr tmp = 0;
179 Dwarf_Op *op;
180 size_t nops;
181 unsigned int regn;
182 Dwarf_Word offs = 0;
183 bool ref = false;
184 const char *regs;
185 int ret, ret2 = 0;
186
187 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
188 goto static_var;
189
190 /* TODO: handle more than 1 exprs */
191 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
192 return -EINVAL; /* Broken DIE ? */
193 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
194 ret = dwarf_entrypc(sp_die, &tmp);
195 if (ret)
196 return -ENOENT;
197
198 if (probe_conf.show_location_range &&
199 (dwarf_tag(vr_die) == DW_TAG_variable)) {
200 ret2 = -ERANGE;
201 } else if (addr != tmp ||
202 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
203 return -ENOENT;
204 }
205
206 ret = dwarf_highpc(sp_die, &tmp);
207 if (ret)
208 return -ENOENT;
209 /*
210 * This is fuzzed by fentry mcount. We try to find the
211 * parameter location at the earliest address.
212 */
213 for (addr += 1; addr <= tmp; addr++) {
214 if (dwarf_getlocation_addr(&attr, addr, &op,
215 &nops, 1) > 0)
216 goto found;
217 }
218 return -ENOENT;
219 }
220 found:
221 if (nops == 0)
222 /* TODO: Support const_value */
223 return -ENOENT;
224
225 if (op->atom == DW_OP_addr) {
226 static_var:
227 if (!tvar)
228 return ret2;
229 /* Static variables on memory (not stack), make @varname */
230 ret = strlen(dwarf_diename(vr_die));
231 tvar->value = zalloc(ret + 2);
232 if (tvar->value == NULL)
233 return -ENOMEM;
234 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
235 tvar->ref = alloc_trace_arg_ref((long)offs);
236 if (tvar->ref == NULL)
237 return -ENOMEM;
238 return ret2;
239 }
240
241 /* If this is based on frame buffer, set the offset */
242 if (op->atom == DW_OP_fbreg) {
243 if (fb_ops == NULL)
244 return -ENOTSUP;
245 ref = true;
246 offs = op->number;
247 op = &fb_ops[0];
248 }
249
250 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
251 regn = op->atom - DW_OP_breg0;
252 offs += op->number;
253 ref = true;
254 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
255 regn = op->atom - DW_OP_reg0;
256 } else if (op->atom == DW_OP_bregx) {
257 regn = op->number;
258 offs += op->number2;
259 ref = true;
260 } else if (op->atom == DW_OP_regx) {
261 regn = op->number;
262 } else {
263 pr_debug("DW_OP %x is not supported.\n", op->atom);
264 return -ENOTSUP;
265 }
266
267 if (!tvar)
268 return ret2;
269
270 regs = get_dwarf_regstr(regn, machine);
271 if (!regs) {
272 /* This should be a bug in DWARF or this tool */
273 pr_warning("Mapping for the register number %u "
274 "missing on this architecture.\n", regn);
275 return -ENOTSUP;
276 }
277
278 tvar->value = strdup(regs);
279 if (tvar->value == NULL)
280 return -ENOMEM;
281
282 if (ref) {
283 tvar->ref = alloc_trace_arg_ref((long)offs);
284 if (tvar->ref == NULL)
285 return -ENOMEM;
286 }
287 return ret2;
288 }
289
290 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
291
292 static int convert_variable_type(Dwarf_Die *vr_die,
293 struct probe_trace_arg *tvar,
294 const char *cast)
295 {
296 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
297 Dwarf_Die type;
298 char buf[16];
299 char sbuf[STRERR_BUFSIZE];
300 int bsize, boffs, total;
301 int ret;
302 char prefix;
303
304 /* TODO: check all types */
305 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
306 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
307 /* Non string type is OK */
308 /* and respect signedness/hexadecimal cast */
309 tvar->type = strdup(cast);
310 return (tvar->type == NULL) ? -ENOMEM : 0;
311 }
312
313 bsize = dwarf_bitsize(vr_die);
314 if (bsize > 0) {
315 /* This is a bitfield */
316 boffs = dwarf_bitoffset(vr_die);
317 total = dwarf_bytesize(vr_die);
318 if (boffs < 0 || total < 0)
319 return -ENOENT;
320 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
321 BYTES_TO_BITS(total));
322 goto formatted;
323 }
324
325 if (die_get_real_type(vr_die, &type) == NULL) {
326 pr_warning("Failed to get a type information of %s.\n",
327 dwarf_diename(vr_die));
328 return -ENOENT;
329 }
330
331 pr_debug("%s type is %s.\n",
332 dwarf_diename(vr_die), dwarf_diename(&type));
333
334 if (cast && strcmp(cast, "string") == 0) { /* String type */
335 ret = dwarf_tag(&type);
336 if (ret != DW_TAG_pointer_type &&
337 ret != DW_TAG_array_type) {
338 pr_warning("Failed to cast into string: "
339 "%s(%s) is not a pointer nor array.\n",
340 dwarf_diename(vr_die), dwarf_diename(&type));
341 return -EINVAL;
342 }
343 if (die_get_real_type(&type, &type) == NULL) {
344 pr_warning("Failed to get a type"
345 " information.\n");
346 return -ENOENT;
347 }
348 if (ret == DW_TAG_pointer_type) {
349 while (*ref_ptr)
350 ref_ptr = &(*ref_ptr)->next;
351 /* Add new reference with offset +0 */
352 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
353 if (*ref_ptr == NULL) {
354 pr_warning("Out of memory error\n");
355 return -ENOMEM;
356 }
357 }
358 if (!die_compare_name(&type, "char") &&
359 !die_compare_name(&type, "unsigned char")) {
360 pr_warning("Failed to cast into string: "
361 "%s is not (unsigned) char *.\n",
362 dwarf_diename(vr_die));
363 return -EINVAL;
364 }
365 tvar->type = strdup(cast);
366 return (tvar->type == NULL) ? -ENOMEM : 0;
367 }
368
369 if (cast && (strcmp(cast, "u") == 0))
370 prefix = 'u';
371 else if (cast && (strcmp(cast, "s") == 0))
372 prefix = 's';
373 else if (cast && (strcmp(cast, "x") == 0) &&
374 probe_type_is_available(PROBE_TYPE_X))
375 prefix = 'x';
376 else
377 prefix = die_is_signed_type(&type) ? 's' :
378 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
379
380 ret = dwarf_bytesize(&type);
381 if (ret <= 0)
382 /* No size ... try to use default type */
383 return 0;
384 ret = BYTES_TO_BITS(ret);
385
386 /* Check the bitwidth */
387 if (ret > MAX_BASIC_TYPE_BITS) {
388 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
389 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
390 ret = MAX_BASIC_TYPE_BITS;
391 }
392 ret = snprintf(buf, 16, "%c%d", prefix, ret);
393
394 formatted:
395 if (ret < 0 || ret >= 16) {
396 if (ret >= 16)
397 ret = -E2BIG;
398 pr_warning("Failed to convert variable type: %s\n",
399 str_error_r(-ret, sbuf, sizeof(sbuf)));
400 return ret;
401 }
402 tvar->type = strdup(buf);
403 if (tvar->type == NULL)
404 return -ENOMEM;
405 return 0;
406 }
407
408 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
409 struct perf_probe_arg_field *field,
410 struct probe_trace_arg_ref **ref_ptr,
411 Dwarf_Die *die_mem)
412 {
413 struct probe_trace_arg_ref *ref = *ref_ptr;
414 Dwarf_Die type;
415 Dwarf_Word offs;
416 int ret, tag;
417
418 pr_debug("converting %s in %s\n", field->name, varname);
419 if (die_get_real_type(vr_die, &type) == NULL) {
420 pr_warning("Failed to get the type of %s.\n", varname);
421 return -ENOENT;
422 }
423 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
424 tag = dwarf_tag(&type);
425
426 if (field->name[0] == '[' &&
427 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
428 if (field->next)
429 /* Save original type for next field */
430 memcpy(die_mem, &type, sizeof(*die_mem));
431 /* Get the type of this array */
432 if (die_get_real_type(&type, &type) == NULL) {
433 pr_warning("Failed to get the type of %s.\n", varname);
434 return -ENOENT;
435 }
436 pr_debug2("Array real type: (%x)\n",
437 (unsigned)dwarf_dieoffset(&type));
438 if (tag == DW_TAG_pointer_type) {
439 ref = zalloc(sizeof(struct probe_trace_arg_ref));
440 if (ref == NULL)
441 return -ENOMEM;
442 if (*ref_ptr)
443 (*ref_ptr)->next = ref;
444 else
445 *ref_ptr = ref;
446 }
447 ref->offset += dwarf_bytesize(&type) * field->index;
448 if (!field->next)
449 /* Save vr_die for converting types */
450 memcpy(die_mem, vr_die, sizeof(*die_mem));
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 an 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 an 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 pf->addr = addr;
959 pf->addr += pp->offset;
960 pr_debug("found inline addr: 0x%jx\n",
961 (uintmax_t)pf->addr);
962
963 ret = call_probe_finder(in_die, pf);
964 }
965
966 return ret;
967 }
968
969 /* Callback parameter with return value for libdw */
970 struct dwarf_callback_param {
971 void *data;
972 int retval;
973 };
974
975 /* Search function from function name */
976 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
977 {
978 struct dwarf_callback_param *param = data;
979 struct probe_finder *pf = param->data;
980 struct perf_probe_point *pp = &pf->pev->point;
981
982 /* Check tag and diename */
983 if (!die_is_func_def(sp_die) ||
984 !die_match_name(sp_die, pp->function))
985 return DWARF_CB_OK;
986
987 /* Check declared file */
988 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
989 return DWARF_CB_OK;
990
991 pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
992 pf->fname = dwarf_decl_file(sp_die);
993 if (pp->line) { /* Function relative line */
994 dwarf_decl_line(sp_die, &pf->lno);
995 pf->lno += pp->line;
996 param->retval = find_probe_point_by_line(pf);
997 } else if (die_is_func_instance(sp_die)) {
998 /* Instances always have the entry address */
999 dwarf_entrypc(sp_die, &pf->addr);
1000 /* Real function */
1001 if (pp->lazy_line)
1002 param->retval = find_probe_point_lazy(sp_die, pf);
1003 else {
1004 skip_prologue(sp_die, pf);
1005 pf->addr += pp->offset;
1006 /* TODO: Check the address in this function */
1007 param->retval = call_probe_finder(sp_die, pf);
1008 }
1009 } else if (!probe_conf.no_inlines) {
1010 /* Inlined function: search instances */
1011 param->retval = die_walk_instances(sp_die,
1012 probe_point_inline_cb, (void *)pf);
1013 /* This could be a non-existed inline definition */
1014 if (param->retval == -ENOENT && strisglob(pp->function))
1015 param->retval = 0;
1016 }
1017
1018 /* We need to find other candidates */
1019 if (strisglob(pp->function) && param->retval >= 0) {
1020 param->retval = 0; /* We have to clear the result */
1021 return DWARF_CB_OK;
1022 }
1023
1024 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1025 }
1026
1027 static int find_probe_point_by_func(struct probe_finder *pf)
1028 {
1029 struct dwarf_callback_param _param = {.data = (void *)pf,
1030 .retval = 0};
1031 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1032 return _param.retval;
1033 }
1034
1035 struct pubname_callback_param {
1036 char *function;
1037 char *file;
1038 Dwarf_Die *cu_die;
1039 Dwarf_Die *sp_die;
1040 int found;
1041 };
1042
1043 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1044 {
1045 struct pubname_callback_param *param = data;
1046
1047 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1048 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1049 return DWARF_CB_OK;
1050
1051 if (die_match_name(param->sp_die, param->function)) {
1052 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1053 return DWARF_CB_OK;
1054
1055 if (param->file &&
1056 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1057 return DWARF_CB_OK;
1058
1059 param->found = 1;
1060 return DWARF_CB_ABORT;
1061 }
1062 }
1063
1064 return DWARF_CB_OK;
1065 }
1066
1067 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1068 struct probe_finder *pf)
1069 {
1070 struct perf_probe_point *pp = &pf->pev->point;
1071 Dwarf_Off off, noff;
1072 size_t cuhl;
1073 Dwarf_Die *diep;
1074 int ret = 0;
1075
1076 off = 0;
1077 pf->lcache = intlist__new(NULL);
1078 if (!pf->lcache)
1079 return -ENOMEM;
1080
1081 /* Fastpath: lookup by function name from .debug_pubnames section */
1082 if (pp->function && !strisglob(pp->function)) {
1083 struct pubname_callback_param pubname_param = {
1084 .function = pp->function,
1085 .file = pp->file,
1086 .cu_die = &pf->cu_die,
1087 .sp_die = &pf->sp_die,
1088 .found = 0,
1089 };
1090 struct dwarf_callback_param probe_param = {
1091 .data = pf,
1092 };
1093
1094 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1095 &pubname_param, 0);
1096 if (pubname_param.found) {
1097 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1098 if (ret)
1099 goto found;
1100 }
1101 }
1102
1103 /* Loop on CUs (Compilation Unit) */
1104 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1105 /* Get the DIE(Debugging Information Entry) of this CU */
1106 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1107 if (!diep)
1108 continue;
1109
1110 /* Check if target file is included. */
1111 if (pp->file)
1112 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1113 else
1114 pf->fname = NULL;
1115
1116 if (!pp->file || pf->fname) {
1117 if (pp->function)
1118 ret = find_probe_point_by_func(pf);
1119 else if (pp->lazy_line)
1120 ret = find_probe_point_lazy(&pf->cu_die, pf);
1121 else {
1122 pf->lno = pp->line;
1123 ret = find_probe_point_by_line(pf);
1124 }
1125 if (ret < 0)
1126 break;
1127 }
1128 off = noff;
1129 }
1130
1131 found:
1132 intlist__delete(pf->lcache);
1133 pf->lcache = NULL;
1134
1135 return ret;
1136 }
1137
1138 /* Find probe points from debuginfo */
1139 static int debuginfo__find_probes(struct debuginfo *dbg,
1140 struct probe_finder *pf)
1141 {
1142 int ret = 0;
1143 Elf *elf;
1144 GElf_Ehdr ehdr;
1145
1146 if (pf->cfi_eh || pf->cfi_dbg)
1147 return debuginfo__find_probe_location(dbg, pf);
1148
1149 /* Get the call frame information from this dwarf */
1150 elf = dwarf_getelf(dbg->dbg);
1151 if (elf == NULL)
1152 return -EINVAL;
1153
1154 if (gelf_getehdr(elf, &ehdr) == NULL)
1155 return -EINVAL;
1156
1157 pf->machine = ehdr.e_machine;
1158
1159 #if _ELFUTILS_PREREQ(0, 142)
1160 do {
1161 GElf_Shdr shdr;
1162
1163 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1164 shdr.sh_type == SHT_PROGBITS)
1165 pf->cfi_eh = dwarf_getcfi_elf(elf);
1166
1167 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1168 } while (0);
1169 #endif
1170
1171 ret = debuginfo__find_probe_location(dbg, pf);
1172 return ret;
1173 }
1174
1175 struct local_vars_finder {
1176 struct probe_finder *pf;
1177 struct perf_probe_arg *args;
1178 bool vars;
1179 int max_args;
1180 int nargs;
1181 int ret;
1182 };
1183
1184 /* Collect available variables in this scope */
1185 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1186 {
1187 struct local_vars_finder *vf = data;
1188 struct probe_finder *pf = vf->pf;
1189 int tag;
1190
1191 tag = dwarf_tag(die_mem);
1192 if (tag == DW_TAG_formal_parameter ||
1193 (tag == DW_TAG_variable && vf->vars)) {
1194 if (convert_variable_location(die_mem, vf->pf->addr,
1195 vf->pf->fb_ops, &pf->sp_die,
1196 pf->machine, NULL) == 0) {
1197 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1198 if (vf->args[vf->nargs].var == NULL) {
1199 vf->ret = -ENOMEM;
1200 return DIE_FIND_CB_END;
1201 }
1202 pr_debug(" %s", vf->args[vf->nargs].var);
1203 vf->nargs++;
1204 }
1205 }
1206
1207 if (dwarf_haspc(die_mem, vf->pf->addr))
1208 return DIE_FIND_CB_CONTINUE;
1209 else
1210 return DIE_FIND_CB_SIBLING;
1211 }
1212
1213 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1214 struct perf_probe_arg *args)
1215 {
1216 Dwarf_Die die_mem;
1217 int i;
1218 int n = 0;
1219 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1220 .max_args = MAX_PROBE_ARGS, .ret = 0};
1221
1222 for (i = 0; i < pf->pev->nargs; i++) {
1223 /* var never be NULL */
1224 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1225 vf.vars = true;
1226 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1227 /* Copy normal argument */
1228 args[n] = pf->pev->args[i];
1229 n++;
1230 continue;
1231 }
1232 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1233 vf.nargs = n;
1234 /* Special local variables */
1235 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1236 &die_mem);
1237 pr_debug(" (%d)\n", vf.nargs - n);
1238 if (vf.ret < 0)
1239 return vf.ret;
1240 n = vf.nargs;
1241 }
1242 return n;
1243 }
1244
1245 /* Add a found probe point into trace event list */
1246 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1247 {
1248 struct trace_event_finder *tf =
1249 container_of(pf, struct trace_event_finder, pf);
1250 struct perf_probe_point *pp = &pf->pev->point;
1251 struct probe_trace_event *tev;
1252 struct perf_probe_arg *args = NULL;
1253 int ret, i;
1254
1255 /* Check number of tevs */
1256 if (tf->ntevs == tf->max_tevs) {
1257 pr_warning("Too many( > %d) probe point found.\n",
1258 tf->max_tevs);
1259 return -ERANGE;
1260 }
1261 tev = &tf->tevs[tf->ntevs++];
1262
1263 /* Trace point should be converted from subprogram DIE */
1264 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1265 pp->retprobe, pp->function, &tev->point);
1266 if (ret < 0)
1267 goto end;
1268
1269 tev->point.realname = strdup(dwarf_diename(sc_die));
1270 if (!tev->point.realname) {
1271 ret = -ENOMEM;
1272 goto end;
1273 }
1274
1275 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1276 tev->point.offset);
1277
1278 /* Expand special probe argument if exist */
1279 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1280 if (args == NULL) {
1281 ret = -ENOMEM;
1282 goto end;
1283 }
1284
1285 ret = expand_probe_args(sc_die, pf, args);
1286 if (ret < 0)
1287 goto end;
1288
1289 tev->nargs = ret;
1290 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1291 if (tev->args == NULL) {
1292 ret = -ENOMEM;
1293 goto end;
1294 }
1295
1296 /* Find each argument */
1297 for (i = 0; i < tev->nargs; i++) {
1298 pf->pvar = &args[i];
1299 pf->tvar = &tev->args[i];
1300 /* Variable should be found from scope DIE */
1301 ret = find_variable(sc_die, pf);
1302 if (ret != 0)
1303 break;
1304 }
1305
1306 end:
1307 if (ret) {
1308 clear_probe_trace_event(tev);
1309 tf->ntevs--;
1310 }
1311 free(args);
1312 return ret;
1313 }
1314
1315 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1316 int debuginfo__find_trace_events(struct debuginfo *dbg,
1317 struct perf_probe_event *pev,
1318 struct probe_trace_event **tevs)
1319 {
1320 struct trace_event_finder tf = {
1321 .pf = {.pev = pev, .callback = add_probe_trace_event},
1322 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1323 int ret, i;
1324
1325 /* Allocate result tevs array */
1326 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1327 if (*tevs == NULL)
1328 return -ENOMEM;
1329
1330 tf.tevs = *tevs;
1331 tf.ntevs = 0;
1332
1333 ret = debuginfo__find_probes(dbg, &tf.pf);
1334 if (ret < 0) {
1335 for (i = 0; i < tf.ntevs; i++)
1336 clear_probe_trace_event(&tf.tevs[i]);
1337 zfree(tevs);
1338 return ret;
1339 }
1340
1341 return (ret < 0) ? ret : tf.ntevs;
1342 }
1343
1344 /* Collect available variables in this scope */
1345 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1346 {
1347 struct available_var_finder *af = data;
1348 struct variable_list *vl;
1349 struct strbuf buf = STRBUF_INIT;
1350 int tag, ret;
1351
1352 vl = &af->vls[af->nvls - 1];
1353
1354 tag = dwarf_tag(die_mem);
1355 if (tag == DW_TAG_formal_parameter ||
1356 tag == DW_TAG_variable) {
1357 ret = convert_variable_location(die_mem, af->pf.addr,
1358 af->pf.fb_ops, &af->pf.sp_die,
1359 af->pf.machine, NULL);
1360 if (ret == 0 || ret == -ERANGE) {
1361 int ret2;
1362 bool externs = !af->child;
1363
1364 if (strbuf_init(&buf, 64) < 0)
1365 goto error;
1366
1367 if (probe_conf.show_location_range) {
1368 if (!externs)
1369 ret2 = strbuf_add(&buf,
1370 ret ? "[INV]\t" : "[VAL]\t", 6);
1371 else
1372 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1373 if (ret2)
1374 goto error;
1375 }
1376
1377 ret2 = die_get_varname(die_mem, &buf);
1378
1379 if (!ret2 && probe_conf.show_location_range &&
1380 !externs) {
1381 if (strbuf_addch(&buf, '\t') < 0)
1382 goto error;
1383 ret2 = die_get_var_range(&af->pf.sp_die,
1384 die_mem, &buf);
1385 }
1386
1387 pr_debug("Add new var: %s\n", buf.buf);
1388 if (ret2 == 0) {
1389 strlist__add(vl->vars,
1390 strbuf_detach(&buf, NULL));
1391 }
1392 strbuf_release(&buf);
1393 }
1394 }
1395
1396 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1397 return DIE_FIND_CB_CONTINUE;
1398 else
1399 return DIE_FIND_CB_SIBLING;
1400 error:
1401 strbuf_release(&buf);
1402 pr_debug("Error in strbuf\n");
1403 return DIE_FIND_CB_END;
1404 }
1405
1406 /* Add a found vars into available variables list */
1407 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1408 {
1409 struct available_var_finder *af =
1410 container_of(pf, struct available_var_finder, pf);
1411 struct perf_probe_point *pp = &pf->pev->point;
1412 struct variable_list *vl;
1413 Dwarf_Die die_mem;
1414 int ret;
1415
1416 /* Check number of tevs */
1417 if (af->nvls == af->max_vls) {
1418 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1419 return -ERANGE;
1420 }
1421 vl = &af->vls[af->nvls++];
1422
1423 /* Trace point should be converted from subprogram DIE */
1424 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1425 pp->retprobe, pp->function, &vl->point);
1426 if (ret < 0)
1427 return ret;
1428
1429 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1430 vl->point.offset);
1431
1432 /* Find local variables */
1433 vl->vars = strlist__new(NULL, NULL);
1434 if (vl->vars == NULL)
1435 return -ENOMEM;
1436 af->child = true;
1437 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1438
1439 /* Find external variables */
1440 if (!probe_conf.show_ext_vars)
1441 goto out;
1442 /* Don't need to search child DIE for external vars. */
1443 af->child = false;
1444 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1445
1446 out:
1447 if (strlist__empty(vl->vars)) {
1448 strlist__delete(vl->vars);
1449 vl->vars = NULL;
1450 }
1451
1452 return ret;
1453 }
1454
1455 /*
1456 * Find available variables at given probe point
1457 * Return the number of found probe points. Return 0 if there is no
1458 * matched probe point. Return <0 if an error occurs.
1459 */
1460 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1461 struct perf_probe_event *pev,
1462 struct variable_list **vls)
1463 {
1464 struct available_var_finder af = {
1465 .pf = {.pev = pev, .callback = add_available_vars},
1466 .mod = dbg->mod,
1467 .max_vls = probe_conf.max_probes};
1468 int ret;
1469
1470 /* Allocate result vls array */
1471 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1472 if (*vls == NULL)
1473 return -ENOMEM;
1474
1475 af.vls = *vls;
1476 af.nvls = 0;
1477
1478 ret = debuginfo__find_probes(dbg, &af.pf);
1479 if (ret < 0) {
1480 /* Free vlist for error */
1481 while (af.nvls--) {
1482 zfree(&af.vls[af.nvls].point.symbol);
1483 strlist__delete(af.vls[af.nvls].vars);
1484 }
1485 zfree(vls);
1486 return ret;
1487 }
1488
1489 return (ret < 0) ? ret : af.nvls;
1490 }
1491
1492 /* For the kernel module, we need a special code to get a DIE */
1493 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1494 {
1495 int n, i;
1496 Elf32_Word shndx;
1497 Elf_Scn *scn;
1498 Elf *elf;
1499 GElf_Shdr mem, *shdr;
1500 const char *p;
1501
1502 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1503 if (!elf)
1504 return -EINVAL;
1505
1506 /* Get the number of relocations */
1507 n = dwfl_module_relocations(dbg->mod);
1508 if (n < 0)
1509 return -ENOENT;
1510 /* Search the relocation related .text section */
1511 for (i = 0; i < n; i++) {
1512 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1513 if (strcmp(p, ".text") == 0) {
1514 /* OK, get the section header */
1515 scn = elf_getscn(elf, shndx);
1516 if (!scn)
1517 return -ENOENT;
1518 shdr = gelf_getshdr(scn, &mem);
1519 if (!shdr)
1520 return -ENOENT;
1521 *offs = shdr->sh_addr;
1522 }
1523 }
1524 return 0;
1525 }
1526
1527 /* Reverse search */
1528 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1529 struct perf_probe_point *ppt)
1530 {
1531 Dwarf_Die cudie, spdie, indie;
1532 Dwarf_Addr _addr = 0, baseaddr = 0;
1533 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1534 int baseline = 0, lineno = 0, ret = 0;
1535 bool reloc = false;
1536
1537 retry:
1538 /* Find cu die */
1539 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1540 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1541 addr += baseaddr;
1542 reloc = true;
1543 goto retry;
1544 }
1545 pr_warning("Failed to find debug information for address %lx\n",
1546 addr);
1547 ret = -EINVAL;
1548 goto end;
1549 }
1550
1551 /* Find a corresponding line (filename and lineno) */
1552 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1553 /* Don't care whether it failed or not */
1554
1555 /* Find a corresponding function (name, baseline and baseaddr) */
1556 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1557 /* Get function entry information */
1558 func = basefunc = dwarf_diename(&spdie);
1559 if (!func ||
1560 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1561 dwarf_decl_line(&spdie, &baseline) != 0) {
1562 lineno = 0;
1563 goto post;
1564 }
1565
1566 fname = dwarf_decl_file(&spdie);
1567 if (addr == (unsigned long)baseaddr) {
1568 /* Function entry - Relative line number is 0 */
1569 lineno = baseline;
1570 goto post;
1571 }
1572
1573 /* Track down the inline functions step by step */
1574 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1575 &indie)) {
1576 /* There is an inline function */
1577 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1578 _addr == addr) {
1579 /*
1580 * addr is at an inline function entry.
1581 * In this case, lineno should be the call-site
1582 * line number. (overwrite lineinfo)
1583 */
1584 lineno = die_get_call_lineno(&indie);
1585 fname = die_get_call_file(&indie);
1586 break;
1587 } else {
1588 /*
1589 * addr is in an inline function body.
1590 * Since lineno points one of the lines
1591 * of the inline function, baseline should
1592 * be the entry line of the inline function.
1593 */
1594 tmp = dwarf_diename(&indie);
1595 if (!tmp ||
1596 dwarf_decl_line(&indie, &baseline) != 0)
1597 break;
1598 func = tmp;
1599 spdie = indie;
1600 }
1601 }
1602 /* Verify the lineno and baseline are in a same file */
1603 tmp = dwarf_decl_file(&spdie);
1604 if (!tmp || strcmp(tmp, fname) != 0)
1605 lineno = 0;
1606 }
1607
1608 post:
1609 /* Make a relative line number or an offset */
1610 if (lineno)
1611 ppt->line = lineno - baseline;
1612 else if (basefunc) {
1613 ppt->offset = addr - (unsigned long)baseaddr;
1614 func = basefunc;
1615 }
1616
1617 /* Duplicate strings */
1618 if (func) {
1619 ppt->function = strdup(func);
1620 if (ppt->function == NULL) {
1621 ret = -ENOMEM;
1622 goto end;
1623 }
1624 }
1625 if (fname) {
1626 ppt->file = strdup(fname);
1627 if (ppt->file == NULL) {
1628 zfree(&ppt->function);
1629 ret = -ENOMEM;
1630 goto end;
1631 }
1632 }
1633 end:
1634 if (ret == 0 && (fname || func))
1635 ret = 1; /* Found a point */
1636 return ret;
1637 }
1638
1639 /* Add a line and store the src path */
1640 static int line_range_add_line(const char *src, unsigned int lineno,
1641 struct line_range *lr)
1642 {
1643 /* Copy source path */
1644 if (!lr->path) {
1645 lr->path = strdup(src);
1646 if (lr->path == NULL)
1647 return -ENOMEM;
1648 }
1649 return intlist__add(lr->line_list, lineno);
1650 }
1651
1652 static int line_range_walk_cb(const char *fname, int lineno,
1653 Dwarf_Addr addr __maybe_unused,
1654 void *data)
1655 {
1656 struct line_finder *lf = data;
1657 int err;
1658
1659 if ((strtailcmp(fname, lf->fname) != 0) ||
1660 (lf->lno_s > lineno || lf->lno_e < lineno))
1661 return 0;
1662
1663 err = line_range_add_line(fname, lineno, lf->lr);
1664 if (err < 0 && err != -EEXIST)
1665 return err;
1666
1667 return 0;
1668 }
1669
1670 /* Find line range from its line number */
1671 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1672 {
1673 int ret;
1674
1675 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1676
1677 /* Update status */
1678 if (ret >= 0)
1679 if (!intlist__empty(lf->lr->line_list))
1680 ret = lf->found = 1;
1681 else
1682 ret = 0; /* Lines are not found */
1683 else {
1684 zfree(&lf->lr->path);
1685 }
1686 return ret;
1687 }
1688
1689 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1690 {
1691 int ret = find_line_range_by_line(in_die, data);
1692
1693 /*
1694 * We have to check all instances of inlined function, because
1695 * some execution paths can be optimized out depends on the
1696 * function argument of instances. However, if an error occurs,
1697 * it should be handled by the caller.
1698 */
1699 return ret < 0 ? ret : 0;
1700 }
1701
1702 /* Search function definition from function name */
1703 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1704 {
1705 struct dwarf_callback_param *param = data;
1706 struct line_finder *lf = param->data;
1707 struct line_range *lr = lf->lr;
1708
1709 /* Check declared file */
1710 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1711 return DWARF_CB_OK;
1712
1713 if (die_is_func_def(sp_die) &&
1714 die_match_name(sp_die, lr->function)) {
1715 lf->fname = dwarf_decl_file(sp_die);
1716 dwarf_decl_line(sp_die, &lr->offset);
1717 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1718 lf->lno_s = lr->offset + lr->start;
1719 if (lf->lno_s < 0) /* Overflow */
1720 lf->lno_s = INT_MAX;
1721 lf->lno_e = lr->offset + lr->end;
1722 if (lf->lno_e < 0) /* Overflow */
1723 lf->lno_e = INT_MAX;
1724 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1725 lr->start = lf->lno_s;
1726 lr->end = lf->lno_e;
1727 if (!die_is_func_instance(sp_die))
1728 param->retval = die_walk_instances(sp_die,
1729 line_range_inline_cb, lf);
1730 else
1731 param->retval = find_line_range_by_line(sp_die, lf);
1732 return DWARF_CB_ABORT;
1733 }
1734 return DWARF_CB_OK;
1735 }
1736
1737 static int find_line_range_by_func(struct line_finder *lf)
1738 {
1739 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1740 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1741 return param.retval;
1742 }
1743
1744 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1745 {
1746 struct line_finder lf = {.lr = lr, .found = 0};
1747 int ret = 0;
1748 Dwarf_Off off = 0, noff;
1749 size_t cuhl;
1750 Dwarf_Die *diep;
1751 const char *comp_dir;
1752
1753 /* Fastpath: lookup by function name from .debug_pubnames section */
1754 if (lr->function) {
1755 struct pubname_callback_param pubname_param = {
1756 .function = lr->function, .file = lr->file,
1757 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1758 struct dwarf_callback_param line_range_param = {
1759 .data = (void *)&lf, .retval = 0};
1760
1761 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1762 &pubname_param, 0);
1763 if (pubname_param.found) {
1764 line_range_search_cb(&lf.sp_die, &line_range_param);
1765 if (lf.found)
1766 goto found;
1767 }
1768 }
1769
1770 /* Loop on CUs (Compilation Unit) */
1771 while (!lf.found && ret >= 0) {
1772 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1773 NULL, NULL, NULL) != 0)
1774 break;
1775
1776 /* Get the DIE(Debugging Information Entry) of this CU */
1777 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1778 if (!diep)
1779 continue;
1780
1781 /* Check if target file is included. */
1782 if (lr->file)
1783 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1784 else
1785 lf.fname = 0;
1786
1787 if (!lr->file || lf.fname) {
1788 if (lr->function)
1789 ret = find_line_range_by_func(&lf);
1790 else {
1791 lf.lno_s = lr->start;
1792 lf.lno_e = lr->end;
1793 ret = find_line_range_by_line(NULL, &lf);
1794 }
1795 }
1796 off = noff;
1797 }
1798
1799 found:
1800 /* Store comp_dir */
1801 if (lf.found) {
1802 comp_dir = cu_get_comp_dir(&lf.cu_die);
1803 if (comp_dir) {
1804 lr->comp_dir = strdup(comp_dir);
1805 if (!lr->comp_dir)
1806 ret = -ENOMEM;
1807 }
1808 }
1809
1810 pr_debug("path: %s\n", lr->path);
1811 return (ret < 0) ? ret : lf.found;
1812 }
1813
1814 /*
1815 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1816 * and chop off leading directories that do not exist. Result is passed back as
1817 * a newly allocated path on success.
1818 * Return 0 if file was found and readable, -errno otherwise.
1819 */
1820 int get_real_path(const char *raw_path, const char *comp_dir,
1821 char **new_path)
1822 {
1823 const char *prefix = symbol_conf.source_prefix;
1824
1825 if (!prefix) {
1826 if (raw_path[0] != '/' && comp_dir)
1827 /* If not an absolute path, try to use comp_dir */
1828 prefix = comp_dir;
1829 else {
1830 if (access(raw_path, R_OK) == 0) {
1831 *new_path = strdup(raw_path);
1832 return *new_path ? 0 : -ENOMEM;
1833 } else
1834 return -errno;
1835 }
1836 }
1837
1838 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1839 if (!*new_path)
1840 return -ENOMEM;
1841
1842 for (;;) {
1843 sprintf(*new_path, "%s/%s", prefix, raw_path);
1844
1845 if (access(*new_path, R_OK) == 0)
1846 return 0;
1847
1848 if (!symbol_conf.source_prefix) {
1849 /* In case of searching comp_dir, don't retry */
1850 zfree(new_path);
1851 return -errno;
1852 }
1853
1854 switch (errno) {
1855 case ENAMETOOLONG:
1856 case ENOENT:
1857 case EROFS:
1858 case EFAULT:
1859 raw_path = strchr(++raw_path, '/');
1860 if (!raw_path) {
1861 zfree(new_path);
1862 return -ENOENT;
1863 }
1864 continue;
1865
1866 default:
1867 zfree(new_path);
1868 return -errno;
1869 }
1870 }
1871 }
Linux kernel - Deliverables
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