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Merge tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / tools / perf / util / probe-finder.c
blob76dd349aa48d8e90ae76f8bb876eec307f45b05c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * probe-finder.c : C expression to kprobe event converter
4 *
5 * Written by Masami Hiramatsu <mhiramat@redhat.com>
6 */
7
8 #include <inttypes.h>
9 #include <sys/utsname.h>
10 #include <sys/types.h>
11 #include <sys/stat.h>
12 #include <fcntl.h>
13 #include <errno.h>
14 #include <stdio.h>
15 #include <unistd.h>
16 #include <stdlib.h>
17 #include <string.h>
18 #include <stdarg.h>
19 #include <dwarf-regs.h>
20
21 #include <linux/bitops.h>
22 #include <linux/zalloc.h>
23 #include "event.h"
24 #include "dso.h"
25 #include "debug.h"
26 #include "intlist.h"
27 #include "strbuf.h"
28 #include "strlist.h"
29 #include "symbol.h"
30 #include "probe-finder.h"
31 #include "probe-file.h"
32 #include "string2.h"
33
34 #ifdef HAVE_DEBUGINFOD_SUPPORT
35 #include <elfutils/debuginfod.h>
36 #endif
37
38 /* Kprobe tracer basic type is up to u64 */
39 #define MAX_BASIC_TYPE_BITS 64
40
41 /* Dwarf FL wrappers */
42 static char *debuginfo_path; /* Currently dummy */
43
44 static const Dwfl_Callbacks offline_callbacks = {
45 .find_debuginfo = dwfl_standard_find_debuginfo,
46 .debuginfo_path = &debuginfo_path,
47
48 .section_address = dwfl_offline_section_address,
49
50 /* We use this table for core files too. */
51 .find_elf = dwfl_build_id_find_elf,
52 };
53
54 /* Get a Dwarf from offline image */
55 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
56 const char *path)
57 {
58 GElf_Addr dummy;
59 int fd;
60
61 fd = open(path, O_RDONLY);
62 if (fd < 0)
63 return fd;
64
65 dbg->dwfl = dwfl_begin(&offline_callbacks);
66 if (!dbg->dwfl)
67 goto error;
68
69 dwfl_report_begin(dbg->dwfl);
70 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
71 if (!dbg->mod)
72 goto error;
73
74 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
75 if (!dbg->dbg)
76 goto error;
77
78 dwfl_module_build_id(dbg->mod, &dbg->build_id, &dummy);
79
80 dwfl_report_end(dbg->dwfl, NULL, NULL);
81
82 return 0;
83 error:
84 if (dbg->dwfl)
85 dwfl_end(dbg->dwfl);
86 else
87 close(fd);
88 memset(dbg, 0, sizeof(*dbg));
89
90 return -ENOENT;
91 }
92
93 static struct debuginfo *__debuginfo__new(const char *path)
94 {
95 struct debuginfo *dbg = zalloc(sizeof(*dbg));
96 if (!dbg)
97 return NULL;
98
99 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
100 zfree(&dbg);
101 if (dbg)
102 pr_debug("Open Debuginfo file: %s\n", path);
103 return dbg;
104 }
105
106 enum dso_binary_type distro_dwarf_types[] = {
107 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
108 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
109 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
110 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
111 DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO,
112 DSO_BINARY_TYPE__NOT_FOUND,
113 };
114
115 struct debuginfo *debuginfo__new(const char *path)
116 {
117 enum dso_binary_type *type;
118 char buf[PATH_MAX], nil = '\0';
119 struct dso *dso;
120 struct debuginfo *dinfo = NULL;
121
122 /* Try to open distro debuginfo files */
123 dso = dso__new(path);
124 if (!dso)
125 goto out;
126
127 for (type = distro_dwarf_types;
128 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
129 type++) {
130 if (dso__read_binary_type_filename(dso, *type, &nil,
131 buf, PATH_MAX) < 0)
132 continue;
133 dinfo = __debuginfo__new(buf);
134 }
135 dso__put(dso);
136
137 out:
138 /* if failed to open all distro debuginfo, open given binary */
139 return dinfo ? : __debuginfo__new(path);
140 }
141
142 void debuginfo__delete(struct debuginfo *dbg)
143 {
144 if (dbg) {
145 if (dbg->dwfl)
146 dwfl_end(dbg->dwfl);
147 free(dbg);
148 }
149 }
150
151 /*
152 * Probe finder related functions
153 */
154
155 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
156 {
157 struct probe_trace_arg_ref *ref;
158 ref = zalloc(sizeof(struct probe_trace_arg_ref));
159 if (ref != NULL)
160 ref->offset = offs;
161 return ref;
162 }
163
164 /*
165 * Convert a location into trace_arg.
166 * If tvar == NULL, this just checks variable can be converted.
167 * If fentry == true and vr_die is a parameter, do huristic search
168 * for the location fuzzed by function entry mcount.
169 */
170 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
171 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
172 unsigned int machine,
173 struct probe_trace_arg *tvar)
174 {
175 Dwarf_Attribute attr;
176 Dwarf_Addr tmp = 0;
177 Dwarf_Op *op;
178 size_t nops;
179 unsigned int regn;
180 Dwarf_Word offs = 0;
181 bool ref = false;
182 const char *regs;
183 int ret, ret2 = 0;
184
185 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
186 goto static_var;
187
188 /* Constant value */
189 if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
190 immediate_value_is_supported()) {
191 Dwarf_Sword snum;
192
193 dwarf_formsdata(&attr, &snum);
194 ret = asprintf(&tvar->value, "\\%ld", (long)snum);
195
196 return ret < 0 ? -ENOMEM : 0;
197 }
198
199 /* TODO: handle more than 1 exprs */
200 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
201 return -EINVAL; /* Broken DIE ? */
202 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
203 ret = dwarf_entrypc(sp_die, &tmp);
204 if (ret)
205 return -ENOENT;
206
207 if (probe_conf.show_location_range &&
208 (dwarf_tag(vr_die) == DW_TAG_variable)) {
209 ret2 = -ERANGE;
210 } else if (addr != tmp ||
211 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
212 return -ENOENT;
213 }
214
215 ret = dwarf_highpc(sp_die, &tmp);
216 if (ret)
217 return -ENOENT;
218 /*
219 * This is fuzzed by fentry mcount. We try to find the
220 * parameter location at the earliest address.
221 */
222 for (addr += 1; addr <= tmp; addr++) {
223 if (dwarf_getlocation_addr(&attr, addr, &op,
224 &nops, 1) > 0)
225 goto found;
226 }
227 return -ENOENT;
228 }
229 found:
230 if (nops == 0)
231 /* TODO: Support const_value */
232 return -ENOENT;
233
234 if (op->atom == DW_OP_addr) {
235 static_var:
236 if (!tvar)
237 return ret2;
238 /* Static variables on memory (not stack), make @varname */
239 ret = strlen(dwarf_diename(vr_die));
240 tvar->value = zalloc(ret + 2);
241 if (tvar->value == NULL)
242 return -ENOMEM;
243 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
244 tvar->ref = alloc_trace_arg_ref((long)offs);
245 if (tvar->ref == NULL)
246 return -ENOMEM;
247 return ret2;
248 }
249
250 /* If this is based on frame buffer, set the offset */
251 if (op->atom == DW_OP_fbreg) {
252 if (fb_ops == NULL)
253 return -ENOTSUP;
254 ref = true;
255 offs = op->number;
256 op = &fb_ops[0];
257 }
258
259 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
260 regn = op->atom - DW_OP_breg0;
261 offs += op->number;
262 ref = true;
263 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
264 regn = op->atom - DW_OP_reg0;
265 } else if (op->atom == DW_OP_bregx) {
266 regn = op->number;
267 offs += op->number2;
268 ref = true;
269 } else if (op->atom == DW_OP_regx) {
270 regn = op->number;
271 } else {
272 pr_debug("DW_OP %x is not supported.\n", op->atom);
273 return -ENOTSUP;
274 }
275
276 if (!tvar)
277 return ret2;
278
279 regs = get_dwarf_regstr(regn, machine);
280 if (!regs) {
281 /* This should be a bug in DWARF or this tool */
282 pr_warning("Mapping for the register number %u "
283 "missing on this architecture.\n", regn);
284 return -ENOTSUP;
285 }
286
287 tvar->value = strdup(regs);
288 if (tvar->value == NULL)
289 return -ENOMEM;
290
291 if (ref) {
292 tvar->ref = alloc_trace_arg_ref((long)offs);
293 if (tvar->ref == NULL)
294 return -ENOMEM;
295 }
296 return ret2;
297 }
298
299 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
300
301 static int convert_variable_type(Dwarf_Die *vr_die,
302 struct probe_trace_arg *tvar,
303 const char *cast, bool user_access)
304 {
305 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
306 Dwarf_Die type;
307 char buf[16];
308 char sbuf[STRERR_BUFSIZE];
309 int bsize, boffs, total;
310 int ret;
311 char prefix;
312
313 /* TODO: check all types */
314 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "ustring") &&
315 strcmp(cast, "x") != 0 &&
316 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
317 /* Non string type is OK */
318 /* and respect signedness/hexadecimal cast */
319 tvar->type = strdup(cast);
320 return (tvar->type == NULL) ? -ENOMEM : 0;
321 }
322
323 bsize = dwarf_bitsize(vr_die);
324 if (bsize > 0) {
325 /* This is a bitfield */
326 boffs = dwarf_bitoffset(vr_die);
327 total = dwarf_bytesize(vr_die);
328 if (boffs < 0 || total < 0)
329 return -ENOENT;
330 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
331 BYTES_TO_BITS(total));
332 goto formatted;
333 }
334
335 if (die_get_real_type(vr_die, &type) == NULL) {
336 pr_warning("Failed to get a type information of %s.\n",
337 dwarf_diename(vr_die));
338 return -ENOENT;
339 }
340
341 pr_debug("%s type is %s.\n",
342 dwarf_diename(vr_die), dwarf_diename(&type));
343
344 if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
345 /* String type */
346 ret = dwarf_tag(&type);
347 if (ret != DW_TAG_pointer_type &&
348 ret != DW_TAG_array_type) {
349 pr_warning("Failed to cast into string: "
350 "%s(%s) is not a pointer nor array.\n",
351 dwarf_diename(vr_die), dwarf_diename(&type));
352 return -EINVAL;
353 }
354 if (die_get_real_type(&type, &type) == NULL) {
355 pr_warning("Failed to get a type"
356 " information.\n");
357 return -ENOENT;
358 }
359 if (ret == DW_TAG_pointer_type) {
360 while (*ref_ptr)
361 ref_ptr = &(*ref_ptr)->next;
362 /* Add new reference with offset +0 */
363 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
364 if (*ref_ptr == NULL) {
365 pr_warning("Out of memory error\n");
366 return -ENOMEM;
367 }
368 (*ref_ptr)->user_access = user_access;
369 }
370 if (!die_compare_name(&type, "char") &&
371 !die_compare_name(&type, "unsigned char")) {
372 pr_warning("Failed to cast into string: "
373 "%s is not (unsigned) char *.\n",
374 dwarf_diename(vr_die));
375 return -EINVAL;
376 }
377 tvar->type = strdup(cast);
378 return (tvar->type == NULL) ? -ENOMEM : 0;
379 }
380
381 if (cast && (strcmp(cast, "u") == 0))
382 prefix = 'u';
383 else if (cast && (strcmp(cast, "s") == 0))
384 prefix = 's';
385 else if (cast && (strcmp(cast, "x") == 0) &&
386 probe_type_is_available(PROBE_TYPE_X))
387 prefix = 'x';
388 else
389 prefix = die_is_signed_type(&type) ? 's' :
390 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
391
392 ret = dwarf_bytesize(&type);
393 if (ret <= 0)
394 /* No size ... try to use default type */
395 return 0;
396 ret = BYTES_TO_BITS(ret);
397
398 /* Check the bitwidth */
399 if (ret > MAX_BASIC_TYPE_BITS) {
400 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
401 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
402 ret = MAX_BASIC_TYPE_BITS;
403 }
404 ret = snprintf(buf, 16, "%c%d", prefix, ret);
405
406 formatted:
407 if (ret < 0 || ret >= 16) {
408 if (ret >= 16)
409 ret = -E2BIG;
410 pr_warning("Failed to convert variable type: %s\n",
411 str_error_r(-ret, sbuf, sizeof(sbuf)));
412 return ret;
413 }
414 tvar->type = strdup(buf);
415 if (tvar->type == NULL)
416 return -ENOMEM;
417 return 0;
418 }
419
420 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
421 struct perf_probe_arg_field *field,
422 struct probe_trace_arg_ref **ref_ptr,
423 Dwarf_Die *die_mem, bool user_access)
424 {
425 struct probe_trace_arg_ref *ref = *ref_ptr;
426 Dwarf_Die type;
427 Dwarf_Word offs;
428 int ret, tag;
429
430 pr_debug("converting %s in %s\n", field->name, varname);
431 if (die_get_real_type(vr_die, &type) == NULL) {
432 pr_warning("Failed to get the type of %s.\n", varname);
433 return -ENOENT;
434 }
435 pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
436 (unsigned)dwarf_dieoffset(&type));
437 tag = dwarf_tag(&type);
438
439 if (field->name[0] == '[' &&
440 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
441 /* Save original type for next field or type */
442 memcpy(die_mem, &type, sizeof(*die_mem));
443 /* Get the type of this array */
444 if (die_get_real_type(&type, &type) == NULL) {
445 pr_warning("Failed to get the type of %s.\n", varname);
446 return -ENOENT;
447 }
448 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
449 (unsigned)dwarf_dieoffset(&type));
450 if (tag == DW_TAG_pointer_type) {
451 ref = zalloc(sizeof(struct probe_trace_arg_ref));
452 if (ref == NULL)
453 return -ENOMEM;
454 if (*ref_ptr)
455 (*ref_ptr)->next = ref;
456 else
457 *ref_ptr = ref;
458 }
459 ref->offset += dwarf_bytesize(&type) * field->index;
460 ref->user_access = user_access;
461 goto next;
462 } else if (tag == DW_TAG_pointer_type) {
463 /* Check the pointer and dereference */
464 if (!field->ref) {
465 pr_err("Semantic error: %s must be referred by '->'\n",
466 field->name);
467 return -EINVAL;
468 }
469 /* Get the type pointed by this pointer */
470 if (die_get_real_type(&type, &type) == NULL) {
471 pr_warning("Failed to get the type of %s.\n", varname);
472 return -ENOENT;
473 }
474 /* Verify it is a data structure */
475 tag = dwarf_tag(&type);
476 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
477 pr_warning("%s is not a data structure nor a union.\n",
478 varname);
479 return -EINVAL;
480 }
481
482 ref = zalloc(sizeof(struct probe_trace_arg_ref));
483 if (ref == NULL)
484 return -ENOMEM;
485 if (*ref_ptr)
486 (*ref_ptr)->next = ref;
487 else
488 *ref_ptr = ref;
489 } else {
490 /* Verify it is a data structure */
491 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
492 pr_warning("%s is not a data structure nor a union.\n",
493 varname);
494 return -EINVAL;
495 }
496 if (field->name[0] == '[') {
497 pr_err("Semantic error: %s is not a pointer"
498 " nor array.\n", varname);
499 return -EINVAL;
500 }
501 /* While prcessing unnamed field, we don't care about this */
502 if (field->ref && dwarf_diename(vr_die)) {
503 pr_err("Semantic error: %s must be referred by '.'\n",
504 field->name);
505 return -EINVAL;
506 }
507 if (!ref) {
508 pr_warning("Structure on a register is not "
509 "supported yet.\n");
510 return -ENOTSUP;
511 }
512 }
513
514 if (die_find_member(&type, field->name, die_mem) == NULL) {
515 pr_warning("%s(type:%s) has no member %s.\n", varname,
516 dwarf_diename(&type), field->name);
517 return -EINVAL;
518 }
519
520 /* Get the offset of the field */
521 if (tag == DW_TAG_union_type) {
522 offs = 0;
523 } else {
524 ret = die_get_data_member_location(die_mem, &offs);
525 if (ret < 0) {
526 pr_warning("Failed to get the offset of %s.\n",
527 field->name);
528 return ret;
529 }
530 }
531 ref->offset += (long)offs;
532 ref->user_access = user_access;
533
534 /* If this member is unnamed, we need to reuse this field */
535 if (!dwarf_diename(die_mem))
536 return convert_variable_fields(die_mem, varname, field,
537 &ref, die_mem, user_access);
538
539 next:
540 /* Converting next field */
541 if (field->next)
542 return convert_variable_fields(die_mem, field->name,
543 field->next, &ref, die_mem, user_access);
544 else
545 return 0;
546 }
547
548 static void print_var_not_found(const char *varname)
549 {
550 pr_err("Failed to find the location of the '%s' variable at this address.\n"
551 " Perhaps it has been optimized out.\n"
552 " Use -V with the --range option to show '%s' location range.\n",
553 varname, varname);
554 }
555
556 /* Show a variables in kprobe event format */
557 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
558 {
559 Dwarf_Die die_mem;
560 int ret;
561
562 pr_debug("Converting variable %s into trace event.\n",
563 dwarf_diename(vr_die));
564
565 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
566 &pf->sp_die, pf->machine, pf->tvar);
567 if (ret == -ENOENT && pf->skip_empty_arg)
568 /* This can be found in other place. skip it */
569 return 0;
570 if (ret == -ENOENT || ret == -EINVAL) {
571 print_var_not_found(pf->pvar->var);
572 } else if (ret == -ENOTSUP)
573 pr_err("Sorry, we don't support this variable location yet.\n");
574 else if (ret == 0 && pf->pvar->field) {
575 ret = convert_variable_fields(vr_die, pf->pvar->var,
576 pf->pvar->field, &pf->tvar->ref,
577 &die_mem, pf->pvar->user_access);
578 vr_die = &die_mem;
579 }
580 if (ret == 0)
581 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
582 pf->pvar->user_access);
583 /* *expr will be cached in libdw. Don't free it. */
584 return ret;
585 }
586
587 /* Find a variable in a scope DIE */
588 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
589 {
590 Dwarf_Die vr_die;
591 char *buf, *ptr;
592 int ret = 0;
593
594 /* Copy raw parameters */
595 if (!is_c_varname(pf->pvar->var))
596 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
597
598 if (pf->pvar->name)
599 pf->tvar->name = strdup(pf->pvar->name);
600 else {
601 buf = synthesize_perf_probe_arg(pf->pvar);
602 if (!buf)
603 return -ENOMEM;
604 ptr = strchr(buf, ':'); /* Change type separator to _ */
605 if (ptr)
606 *ptr = '_';
607 pf->tvar->name = buf;
608 }
609 if (pf->tvar->name == NULL)
610 return -ENOMEM;
611
612 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
613 /* Search child die for local variables and parameters. */
614 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
615 /* Search again in global variables */
616 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
617 0, &vr_die)) {
618 if (pf->skip_empty_arg)
619 return 0;
620 pr_warning("Failed to find '%s' in this function.\n",
621 pf->pvar->var);
622 ret = -ENOENT;
623 }
624 }
625 if (ret >= 0)
626 ret = convert_variable(&vr_die, pf);
627
628 return ret;
629 }
630
631 /* Convert subprogram DIE to trace point */
632 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
633 Dwarf_Addr paddr, bool retprobe,
634 const char *function,
635 struct probe_trace_point *tp)
636 {
637 Dwarf_Addr eaddr;
638 GElf_Sym sym;
639 const char *symbol;
640
641 /* Verify the address is correct */
642 if (!dwarf_haspc(sp_die, paddr)) {
643 pr_warning("Specified offset is out of %s\n",
644 dwarf_diename(sp_die));
645 return -EINVAL;
646 }
647
648 if (dwarf_entrypc(sp_die, &eaddr) == 0) {
649 /* If the DIE has entrypc, use it. */
650 symbol = dwarf_diename(sp_die);
651 } else {
652 /* Try to get actual symbol name and address from symtab */
653 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
654 eaddr = sym.st_value;
655 }
656 if (!symbol) {
657 pr_warning("Failed to find symbol at 0x%lx\n",
658 (unsigned long)paddr);
659 return -ENOENT;
660 }
661
662 tp->offset = (unsigned long)(paddr - eaddr);
663 tp->address = (unsigned long)paddr;
664 tp->symbol = strdup(symbol);
665 if (!tp->symbol)
666 return -ENOMEM;
667
668 /* Return probe must be on the head of a subprogram */
669 if (retprobe) {
670 if (eaddr != paddr) {
671 pr_warning("Failed to find \"%s%%return\",\n"
672 " because %s is an inlined function and"
673 " has no return point.\n", function,
674 function);
675 return -EINVAL;
676 }
677 tp->retprobe = true;
678 }
679
680 return 0;
681 }
682
683 /* Call probe_finder callback with scope DIE */
684 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
685 {
686 Dwarf_Attribute fb_attr;
687 Dwarf_Frame *frame = NULL;
688 size_t nops;
689 int ret;
690
691 if (!sc_die) {
692 pr_err("Caller must pass a scope DIE. Program error.\n");
693 return -EINVAL;
694 }
695
696 /* If not a real subprogram, find a real one */
697 if (!die_is_func_def(sc_die)) {
698 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
699 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
700 pr_warning("Ignoring tail call from %s\n",
701 dwarf_diename(&pf->sp_die));
702 return 0;
703 } else {
704 pr_warning("Failed to find probe point in any "
705 "functions.\n");
706 return -ENOENT;
707 }
708 }
709 } else
710 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
711
712 /* Get the frame base attribute/ops from subprogram */
713 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
714 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
715 if (ret <= 0 || nops == 0) {
716 pf->fb_ops = NULL;
717 #if _ELFUTILS_PREREQ(0, 142)
718 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
719 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
720 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
721 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
722 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
723 pr_warning("Failed to get call frame on 0x%jx\n",
724 (uintmax_t)pf->addr);
725 free(frame);
726 return -ENOENT;
727 }
728 #endif
729 }
730
731 /* Call finder's callback handler */
732 ret = pf->callback(sc_die, pf);
733
734 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
735 free(frame);
736 pf->fb_ops = NULL;
737
738 return ret;
739 }
740
741 struct find_scope_param {
742 const char *function;
743 const char *file;
744 int line;
745 int diff;
746 Dwarf_Die *die_mem;
747 bool found;
748 };
749
750 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
751 {
752 struct find_scope_param *fsp = data;
753 const char *file;
754 int lno;
755
756 /* Skip if declared file name does not match */
757 if (fsp->file) {
758 file = dwarf_decl_file(fn_die);
759 if (!file || strcmp(fsp->file, file) != 0)
760 return 0;
761 }
762 /* If the function name is given, that's what user expects */
763 if (fsp->function) {
764 if (die_match_name(fn_die, fsp->function)) {
765 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
766 fsp->found = true;
767 return 1;
768 }
769 } else {
770 /* With the line number, find the nearest declared DIE */
771 dwarf_decl_line(fn_die, &lno);
772 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
773 /* Keep a candidate and continue */
774 fsp->diff = fsp->line - lno;
775 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
776 fsp->found = true;
777 }
778 }
779 return 0;
780 }
781
782 /* Return innermost DIE */
783 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
784 {
785 struct find_scope_param *fsp = data;
786
787 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
788 fsp->found = true;
789 return 1;
790 }
791
792 /* Find an appropriate scope fits to given conditions */
793 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
794 {
795 struct find_scope_param fsp = {
796 .function = pf->pev->point.function,
797 .file = pf->fname,
798 .line = pf->lno,
799 .diff = INT_MAX,
800 .die_mem = die_mem,
801 .found = false,
802 };
803 int ret;
804
805 ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
806 &fsp);
807 if (!ret && !fsp.found)
808 cu_walk_functions_at(&pf->cu_die, pf->addr,
809 find_inner_scope_cb, &fsp);
810
811 return fsp.found ? die_mem : NULL;
812 }
813
814 static int verify_representive_line(struct probe_finder *pf, const char *fname,
815 int lineno, Dwarf_Addr addr)
816 {
817 const char *__fname, *__func = NULL;
818 Dwarf_Die die_mem;
819 int __lineno;
820
821 /* Verify line number and address by reverse search */
822 if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
823 return 0;
824
825 pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
826 if (strcmp(fname, __fname) || lineno == __lineno)
827 return 0;
828
829 pr_warning("This line is sharing the address with other lines.\n");
830
831 if (pf->pev->point.function) {
832 /* Find best match function name and lines */
833 pf->addr = addr;
834 if (find_best_scope(pf, &die_mem)
835 && die_match_name(&die_mem, pf->pev->point.function)
836 && dwarf_decl_line(&die_mem, &lineno) == 0) {
837 __func = dwarf_diename(&die_mem);
838 __lineno -= lineno;
839 }
840 }
841 pr_warning("Please try to probe at %s:%d instead.\n",
842 __func ? : __fname, __lineno);
843
844 return -ENOENT;
845 }
846
847 static int probe_point_line_walker(const char *fname, int lineno,
848 Dwarf_Addr addr, void *data)
849 {
850 struct probe_finder *pf = data;
851 Dwarf_Die *sc_die, die_mem;
852 int ret;
853
854 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
855 return 0;
856
857 if (verify_representive_line(pf, fname, lineno, addr))
858 return -ENOENT;
859
860 pf->addr = addr;
861 sc_die = find_best_scope(pf, &die_mem);
862 if (!sc_die) {
863 pr_warning("Failed to find scope of probe point.\n");
864 return -ENOENT;
865 }
866
867 ret = call_probe_finder(sc_die, pf);
868
869 /* Continue if no error, because the line will be in inline function */
870 return ret < 0 ? ret : 0;
871 }
872
873 /* Find probe point from its line number */
874 static int find_probe_point_by_line(struct probe_finder *pf)
875 {
876 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
877 }
878
879 /* Find lines which match lazy pattern */
880 static int find_lazy_match_lines(struct intlist *list,
881 const char *fname, const char *pat)
882 {
883 FILE *fp;
884 char *line = NULL;
885 size_t line_len;
886 ssize_t len;
887 int count = 0, linenum = 1;
888 char sbuf[STRERR_BUFSIZE];
889
890 fp = fopen(fname, "r");
891 if (!fp) {
892 pr_warning("Failed to open %s: %s\n", fname,
893 str_error_r(errno, sbuf, sizeof(sbuf)));
894 return -errno;
895 }
896
897 while ((len = getline(&line, &line_len, fp)) > 0) {
898
899 if (line[len - 1] == '\n')
900 line[len - 1] = '\0';
901
902 if (strlazymatch(line, pat)) {
903 intlist__add(list, linenum);
904 count++;
905 }
906 linenum++;
907 }
908
909 if (ferror(fp))
910 count = -errno;
911 free(line);
912 fclose(fp);
913
914 if (count == 0)
915 pr_debug("No matched lines found in %s.\n", fname);
916 return count;
917 }
918
919 static int probe_point_lazy_walker(const char *fname, int lineno,
920 Dwarf_Addr addr, void *data)
921 {
922 struct probe_finder *pf = data;
923 Dwarf_Die *sc_die, die_mem;
924 int ret;
925
926 if (!intlist__has_entry(pf->lcache, lineno) ||
927 strtailcmp(fname, pf->fname) != 0)
928 return 0;
929
930 pr_debug("Probe line found: line:%d addr:0x%llx\n",
931 lineno, (unsigned long long)addr);
932 pf->addr = addr;
933 pf->lno = lineno;
934 sc_die = find_best_scope(pf, &die_mem);
935 if (!sc_die) {
936 pr_warning("Failed to find scope of probe point.\n");
937 return -ENOENT;
938 }
939
940 ret = call_probe_finder(sc_die, pf);
941
942 /*
943 * Continue if no error, because the lazy pattern will match
944 * to other lines
945 */
946 return ret < 0 ? ret : 0;
947 }
948
949 /* Find probe points from lazy pattern */
950 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
951 {
952 struct build_id bid;
953 char sbuild_id[SBUILD_ID_SIZE] = "";
954 int ret = 0;
955 char *fpath;
956
957 if (intlist__empty(pf->lcache)) {
958 const char *comp_dir;
959
960 comp_dir = cu_get_comp_dir(&pf->cu_die);
961 if (pf->dbg->build_id) {
962 build_id__init(&bid, pf->dbg->build_id, BUILD_ID_SIZE);
963 build_id__sprintf(&bid, sbuild_id);
964 }
965 ret = find_source_path(pf->fname, sbuild_id, comp_dir, &fpath);
966 if (ret < 0) {
967 pr_warning("Failed to find source file path.\n");
968 return ret;
969 }
970
971 /* Matching lazy line pattern */
972 ret = find_lazy_match_lines(pf->lcache, fpath,
973 pf->pev->point.lazy_line);
974 free(fpath);
975 if (ret <= 0)
976 return ret;
977 }
978
979 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
980 }
981
982 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
983 {
984 struct perf_probe_point *pp = &pf->pev->point;
985
986 /* Not uprobe? */
987 if (!pf->pev->uprobes)
988 return;
989
990 /* Compiled with optimization? */
991 if (die_is_optimized_target(&pf->cu_die))
992 return;
993
994 /* Don't know entrypc? */
995 if (!pf->addr)
996 return;
997
998 /* Only FUNC and FUNC@SRC are eligible. */
999 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
1000 pp->offset || pp->abs_address)
1001 return;
1002
1003 /* Not interested in func parameter? */
1004 if (!perf_probe_with_var(pf->pev))
1005 return;
1006
1007 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
1008 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
1009 pf->addr);
1010
1011 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
1012 }
1013
1014 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1015 {
1016 struct probe_finder *pf = data;
1017 struct perf_probe_point *pp = &pf->pev->point;
1018 Dwarf_Addr addr;
1019 int ret;
1020
1021 if (pp->lazy_line)
1022 ret = find_probe_point_lazy(in_die, pf);
1023 else {
1024 /* Get probe address */
1025 if (die_entrypc(in_die, &addr) != 0) {
1026 pr_warning("Failed to get entry address of %s.\n",
1027 dwarf_diename(in_die));
1028 return -ENOENT;
1029 }
1030 if (addr == 0) {
1031 pr_debug("%s has no valid entry address. skipped.\n",
1032 dwarf_diename(in_die));
1033 return -ENOENT;
1034 }
1035 pf->addr = addr;
1036 pf->addr += pp->offset;
1037 pr_debug("found inline addr: 0x%jx\n",
1038 (uintmax_t)pf->addr);
1039
1040 ret = call_probe_finder(in_die, pf);
1041 }
1042
1043 return ret;
1044 }
1045
1046 /* Callback parameter with return value for libdw */
1047 struct dwarf_callback_param {
1048 void *data;
1049 int retval;
1050 };
1051
1052 /* Search function from function name */
1053 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1054 {
1055 struct dwarf_callback_param *param = data;
1056 struct probe_finder *pf = param->data;
1057 struct perf_probe_point *pp = &pf->pev->point;
1058
1059 /* Check tag and diename */
1060 if (!die_is_func_def(sp_die) ||
1061 !die_match_name(sp_die, pp->function))
1062 return DWARF_CB_OK;
1063
1064 /* Check declared file */
1065 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1066 return DWARF_CB_OK;
1067
1068 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1069 (unsigned long)dwarf_dieoffset(sp_die));
1070 pf->fname = dwarf_decl_file(sp_die);
1071 if (pp->line) { /* Function relative line */
1072 dwarf_decl_line(sp_die, &pf->lno);
1073 pf->lno += pp->line;
1074 param->retval = find_probe_point_by_line(pf);
1075 } else if (die_is_func_instance(sp_die)) {
1076 /* Instances always have the entry address */
1077 die_entrypc(sp_die, &pf->addr);
1078 /* But in some case the entry address is 0 */
1079 if (pf->addr == 0) {
1080 pr_debug("%s has no entry PC. Skipped\n",
1081 dwarf_diename(sp_die));
1082 param->retval = 0;
1083 /* Real function */
1084 } else if (pp->lazy_line)
1085 param->retval = find_probe_point_lazy(sp_die, pf);
1086 else {
1087 skip_prologue(sp_die, pf);
1088 pf->addr += pp->offset;
1089 /* TODO: Check the address in this function */
1090 param->retval = call_probe_finder(sp_die, pf);
1091 }
1092 } else if (!probe_conf.no_inlines) {
1093 /* Inlined function: search instances */
1094 param->retval = die_walk_instances(sp_die,
1095 probe_point_inline_cb, (void *)pf);
1096 /* This could be a non-existed inline definition */
1097 if (param->retval == -ENOENT)
1098 param->retval = 0;
1099 }
1100
1101 /* We need to find other candidates */
1102 if (strisglob(pp->function) && param->retval >= 0) {
1103 param->retval = 0; /* We have to clear the result */
1104 return DWARF_CB_OK;
1105 }
1106
1107 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1108 }
1109
1110 static int find_probe_point_by_func(struct probe_finder *pf)
1111 {
1112 struct dwarf_callback_param _param = {.data = (void *)pf,
1113 .retval = 0};
1114 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1115 return _param.retval;
1116 }
1117
1118 struct pubname_callback_param {
1119 char *function;
1120 char *file;
1121 Dwarf_Die *cu_die;
1122 Dwarf_Die *sp_die;
1123 int found;
1124 };
1125
1126 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1127 {
1128 struct pubname_callback_param *param = data;
1129
1130 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1131 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1132 return DWARF_CB_OK;
1133
1134 if (die_match_name(param->sp_die, param->function)) {
1135 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1136 return DWARF_CB_OK;
1137
1138 if (param->file &&
1139 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1140 return DWARF_CB_OK;
1141
1142 param->found = 1;
1143 return DWARF_CB_ABORT;
1144 }
1145 }
1146
1147 return DWARF_CB_OK;
1148 }
1149
1150 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1151 struct probe_finder *pf)
1152 {
1153 struct perf_probe_point *pp = &pf->pev->point;
1154 Dwarf_Off off, noff;
1155 size_t cuhl;
1156 Dwarf_Die *diep;
1157 int ret = 0;
1158
1159 off = 0;
1160 pf->lcache = intlist__new(NULL);
1161 if (!pf->lcache)
1162 return -ENOMEM;
1163
1164 /* Fastpath: lookup by function name from .debug_pubnames section */
1165 if (pp->function && !strisglob(pp->function)) {
1166 struct pubname_callback_param pubname_param = {
1167 .function = pp->function,
1168 .file = pp->file,
1169 .cu_die = &pf->cu_die,
1170 .sp_die = &pf->sp_die,
1171 .found = 0,
1172 };
1173 struct dwarf_callback_param probe_param = {
1174 .data = pf,
1175 };
1176
1177 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1178 &pubname_param, 0);
1179 if (pubname_param.found) {
1180 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1181 if (ret)
1182 goto found;
1183 }
1184 }
1185
1186 /* Loop on CUs (Compilation Unit) */
1187 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1188 /* Get the DIE(Debugging Information Entry) of this CU */
1189 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1190 if (!diep)
1191 continue;
1192
1193 /* Check if target file is included. */
1194 if (pp->file)
1195 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1196 else
1197 pf->fname = NULL;
1198
1199 if (!pp->file || pf->fname) {
1200 if (pp->function)
1201 ret = find_probe_point_by_func(pf);
1202 else if (pp->lazy_line)
1203 ret = find_probe_point_lazy(&pf->cu_die, pf);
1204 else {
1205 pf->lno = pp->line;
1206 ret = find_probe_point_by_line(pf);
1207 }
1208 if (ret < 0)
1209 break;
1210 }
1211 off = noff;
1212 }
1213
1214 found:
1215 intlist__delete(pf->lcache);
1216 pf->lcache = NULL;
1217
1218 return ret;
1219 }
1220
1221 /* Find probe points from debuginfo */
1222 static int debuginfo__find_probes(struct debuginfo *dbg,
1223 struct probe_finder *pf)
1224 {
1225 int ret = 0;
1226 Elf *elf;
1227 GElf_Ehdr ehdr;
1228
1229 if (pf->cfi_eh || pf->cfi_dbg)
1230 return debuginfo__find_probe_location(dbg, pf);
1231
1232 /* Get the call frame information from this dwarf */
1233 elf = dwarf_getelf(dbg->dbg);
1234 if (elf == NULL)
1235 return -EINVAL;
1236
1237 if (gelf_getehdr(elf, &ehdr) == NULL)
1238 return -EINVAL;
1239
1240 pf->machine = ehdr.e_machine;
1241
1242 #if _ELFUTILS_PREREQ(0, 142)
1243 do {
1244 GElf_Shdr shdr;
1245
1246 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1247 shdr.sh_type == SHT_PROGBITS)
1248 pf->cfi_eh = dwarf_getcfi_elf(elf);
1249
1250 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1251 } while (0);
1252 #endif
1253
1254 ret = debuginfo__find_probe_location(dbg, pf);
1255 return ret;
1256 }
1257
1258 struct local_vars_finder {
1259 struct probe_finder *pf;
1260 struct perf_probe_arg *args;
1261 bool vars;
1262 int max_args;
1263 int nargs;
1264 int ret;
1265 };
1266
1267 /* Collect available variables in this scope */
1268 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1269 {
1270 struct local_vars_finder *vf = data;
1271 struct probe_finder *pf = vf->pf;
1272 int tag;
1273
1274 tag = dwarf_tag(die_mem);
1275 if (tag == DW_TAG_formal_parameter ||
1276 (tag == DW_TAG_variable && vf->vars)) {
1277 if (convert_variable_location(die_mem, vf->pf->addr,
1278 vf->pf->fb_ops, &pf->sp_die,
1279 pf->machine, NULL) == 0) {
1280 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1281 if (vf->args[vf->nargs].var == NULL) {
1282 vf->ret = -ENOMEM;
1283 return DIE_FIND_CB_END;
1284 }
1285 pr_debug(" %s", vf->args[vf->nargs].var);
1286 vf->nargs++;
1287 }
1288 }
1289
1290 if (dwarf_haspc(die_mem, vf->pf->addr))
1291 return DIE_FIND_CB_CONTINUE;
1292 else
1293 return DIE_FIND_CB_SIBLING;
1294 }
1295
1296 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1297 struct perf_probe_arg *args)
1298 {
1299 Dwarf_Die die_mem;
1300 int i;
1301 int n = 0;
1302 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1303 .max_args = MAX_PROBE_ARGS, .ret = 0};
1304
1305 for (i = 0; i < pf->pev->nargs; i++) {
1306 /* var never be NULL */
1307 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1308 vf.vars = true;
1309 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1310 /* Copy normal argument */
1311 args[n] = pf->pev->args[i];
1312 n++;
1313 continue;
1314 }
1315 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1316 vf.nargs = n;
1317 /* Special local variables */
1318 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1319 &die_mem);
1320 pr_debug(" (%d)\n", vf.nargs - n);
1321 if (vf.ret < 0)
1322 return vf.ret;
1323 n = vf.nargs;
1324 }
1325 return n;
1326 }
1327
1328 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1329 {
1330 int i;
1331
1332 for (i = 0; i < tf->ntevs; i++) {
1333 if (tf->pf.addr == tf->tevs[i].point.address)
1334 return true;
1335 }
1336 return false;
1337 }
1338
1339 /* Add a found probe point into trace event list */
1340 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1341 {
1342 struct trace_event_finder *tf =
1343 container_of(pf, struct trace_event_finder, pf);
1344 struct perf_probe_point *pp = &pf->pev->point;
1345 struct probe_trace_event *tev;
1346 struct perf_probe_arg *args = NULL;
1347 int ret, i;
1348
1349 /*
1350 * For some reason (e.g. different column assigned to same address)
1351 * This callback can be called with the address which already passed.
1352 * Ignore it first.
1353 */
1354 if (trace_event_finder_overlap(tf))
1355 return 0;
1356
1357 /* Check number of tevs */
1358 if (tf->ntevs == tf->max_tevs) {
1359 pr_warning("Too many( > %d) probe point found.\n",
1360 tf->max_tevs);
1361 return -ERANGE;
1362 }
1363 tev = &tf->tevs[tf->ntevs++];
1364
1365 /* Trace point should be converted from subprogram DIE */
1366 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1367 pp->retprobe, pp->function, &tev->point);
1368 if (ret < 0)
1369 goto end;
1370
1371 tev->point.realname = strdup(dwarf_diename(sc_die));
1372 if (!tev->point.realname) {
1373 ret = -ENOMEM;
1374 goto end;
1375 }
1376
1377 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1378 tev->point.offset);
1379
1380 /* Expand special probe argument if exist */
1381 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1382 if (args == NULL) {
1383 ret = -ENOMEM;
1384 goto end;
1385 }
1386
1387 ret = expand_probe_args(sc_die, pf, args);
1388 if (ret < 0)
1389 goto end;
1390
1391 tev->nargs = ret;
1392 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1393 if (tev->args == NULL) {
1394 ret = -ENOMEM;
1395 goto end;
1396 }
1397
1398 /* Find each argument */
1399 for (i = 0; i < tev->nargs; i++) {
1400 pf->pvar = &args[i];
1401 pf->tvar = &tev->args[i];
1402 /* Variable should be found from scope DIE */
1403 ret = find_variable(sc_die, pf);
1404 if (ret != 0)
1405 break;
1406 }
1407
1408 end:
1409 if (ret) {
1410 clear_probe_trace_event(tev);
1411 tf->ntevs--;
1412 }
1413 free(args);
1414 return ret;
1415 }
1416
1417 static int fill_empty_trace_arg(struct perf_probe_event *pev,
1418 struct probe_trace_event *tevs, int ntevs)
1419 {
1420 char **valp;
1421 char *type;
1422 int i, j, ret;
1423
1424 if (!ntevs)
1425 return -ENOENT;
1426
1427 for (i = 0; i < pev->nargs; i++) {
1428 type = NULL;
1429 for (j = 0; j < ntevs; j++) {
1430 if (tevs[j].args[i].value) {
1431 type = tevs[j].args[i].type;
1432 break;
1433 }
1434 }
1435 if (j == ntevs) {
1436 print_var_not_found(pev->args[i].var);
1437 return -ENOENT;
1438 }
1439 for (j = 0; j < ntevs; j++) {
1440 valp = &tevs[j].args[i].value;
1441 if (*valp)
1442 continue;
1443
1444 ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
1445 if (ret < 0)
1446 return -ENOMEM;
1447 /* Note that type can be NULL */
1448 if (type) {
1449 tevs[j].args[i].type = strdup(type);
1450 if (!tevs[j].args[i].type)
1451 return -ENOMEM;
1452 }
1453 }
1454 }
1455 return 0;
1456 }
1457
1458 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1459 int debuginfo__find_trace_events(struct debuginfo *dbg,
1460 struct perf_probe_event *pev,
1461 struct probe_trace_event **tevs)
1462 {
1463 struct trace_event_finder tf = {
1464 .pf = {.pev = pev, .dbg = dbg, .callback = add_probe_trace_event},
1465 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1466 int ret, i;
1467
1468 /* Allocate result tevs array */
1469 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1470 if (*tevs == NULL)
1471 return -ENOMEM;
1472
1473 tf.tevs = *tevs;
1474 tf.ntevs = 0;
1475
1476 if (pev->nargs != 0 && immediate_value_is_supported())
1477 tf.pf.skip_empty_arg = true;
1478
1479 ret = debuginfo__find_probes(dbg, &tf.pf);
1480 if (ret >= 0 && tf.pf.skip_empty_arg)
1481 ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
1482
1483 if (ret < 0 || tf.ntevs == 0) {
1484 for (i = 0; i < tf.ntevs; i++)
1485 clear_probe_trace_event(&tf.tevs[i]);
1486 zfree(tevs);
1487 return ret;
1488 }
1489
1490 return (ret < 0) ? ret : tf.ntevs;
1491 }
1492
1493 /* Collect available variables in this scope */
1494 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1495 {
1496 struct available_var_finder *af = data;
1497 struct variable_list *vl;
1498 struct strbuf buf = STRBUF_INIT;
1499 int tag, ret;
1500
1501 vl = &af->vls[af->nvls - 1];
1502
1503 tag = dwarf_tag(die_mem);
1504 if (tag == DW_TAG_formal_parameter ||
1505 tag == DW_TAG_variable) {
1506 ret = convert_variable_location(die_mem, af->pf.addr,
1507 af->pf.fb_ops, &af->pf.sp_die,
1508 af->pf.machine, NULL);
1509 if (ret == 0 || ret == -ERANGE) {
1510 int ret2;
1511 bool externs = !af->child;
1512
1513 if (strbuf_init(&buf, 64) < 0)
1514 goto error;
1515
1516 if (probe_conf.show_location_range) {
1517 if (!externs)
1518 ret2 = strbuf_add(&buf,
1519 ret ? "[INV]\t" : "[VAL]\t", 6);
1520 else
1521 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1522 if (ret2)
1523 goto error;
1524 }
1525
1526 ret2 = die_get_varname(die_mem, &buf);
1527
1528 if (!ret2 && probe_conf.show_location_range &&
1529 !externs) {
1530 if (strbuf_addch(&buf, '\t') < 0)
1531 goto error;
1532 ret2 = die_get_var_range(&af->pf.sp_die,
1533 die_mem, &buf);
1534 }
1535
1536 pr_debug("Add new var: %s\n", buf.buf);
1537 if (ret2 == 0) {
1538 strlist__add(vl->vars,
1539 strbuf_detach(&buf, NULL));
1540 }
1541 strbuf_release(&buf);
1542 }
1543 }
1544
1545 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1546 return DIE_FIND_CB_CONTINUE;
1547 else
1548 return DIE_FIND_CB_SIBLING;
1549 error:
1550 strbuf_release(&buf);
1551 pr_debug("Error in strbuf\n");
1552 return DIE_FIND_CB_END;
1553 }
1554
1555 static bool available_var_finder_overlap(struct available_var_finder *af)
1556 {
1557 int i;
1558
1559 for (i = 0; i < af->nvls; i++) {
1560 if (af->pf.addr == af->vls[i].point.address)
1561 return true;
1562 }
1563 return false;
1564
1565 }
1566
1567 /* Add a found vars into available variables list */
1568 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1569 {
1570 struct available_var_finder *af =
1571 container_of(pf, struct available_var_finder, pf);
1572 struct perf_probe_point *pp = &pf->pev->point;
1573 struct variable_list *vl;
1574 Dwarf_Die die_mem;
1575 int ret;
1576
1577 /*
1578 * For some reason (e.g. different column assigned to same address),
1579 * this callback can be called with the address which already passed.
1580 * Ignore it first.
1581 */
1582 if (available_var_finder_overlap(af))
1583 return 0;
1584
1585 /* Check number of tevs */
1586 if (af->nvls == af->max_vls) {
1587 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1588 return -ERANGE;
1589 }
1590 vl = &af->vls[af->nvls++];
1591
1592 /* Trace point should be converted from subprogram DIE */
1593 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1594 pp->retprobe, pp->function, &vl->point);
1595 if (ret < 0)
1596 return ret;
1597
1598 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1599 vl->point.offset);
1600
1601 /* Find local variables */
1602 vl->vars = strlist__new(NULL, NULL);
1603 if (vl->vars == NULL)
1604 return -ENOMEM;
1605 af->child = true;
1606 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1607
1608 /* Find external variables */
1609 if (!probe_conf.show_ext_vars)
1610 goto out;
1611 /* Don't need to search child DIE for external vars. */
1612 af->child = false;
1613 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1614
1615 out:
1616 if (strlist__empty(vl->vars)) {
1617 strlist__delete(vl->vars);
1618 vl->vars = NULL;
1619 }
1620
1621 return ret;
1622 }
1623
1624 /*
1625 * Find available variables at given probe point
1626 * Return the number of found probe points. Return 0 if there is no
1627 * matched probe point. Return <0 if an error occurs.
1628 */
1629 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1630 struct perf_probe_event *pev,
1631 struct variable_list **vls)
1632 {
1633 struct available_var_finder af = {
1634 .pf = {.pev = pev, .dbg = dbg, .callback = add_available_vars},
1635 .mod = dbg->mod,
1636 .max_vls = probe_conf.max_probes};
1637 int ret;
1638
1639 /* Allocate result vls array */
1640 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1641 if (*vls == NULL)
1642 return -ENOMEM;
1643
1644 af.vls = *vls;
1645 af.nvls = 0;
1646
1647 ret = debuginfo__find_probes(dbg, &af.pf);
1648 if (ret < 0) {
1649 /* Free vlist for error */
1650 while (af.nvls--) {
1651 zfree(&af.vls[af.nvls].point.symbol);
1652 strlist__delete(af.vls[af.nvls].vars);
1653 }
1654 zfree(vls);
1655 return ret;
1656 }
1657
1658 return (ret < 0) ? ret : af.nvls;
1659 }
1660
1661 /* For the kernel module, we need a special code to get a DIE */
1662 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1663 bool adjust_offset)
1664 {
1665 int n, i;
1666 Elf32_Word shndx;
1667 Elf_Scn *scn;
1668 Elf *elf;
1669 GElf_Shdr mem, *shdr;
1670 const char *p;
1671
1672 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1673 if (!elf)
1674 return -EINVAL;
1675
1676 /* Get the number of relocations */
1677 n = dwfl_module_relocations(dbg->mod);
1678 if (n < 0)
1679 return -ENOENT;
1680 /* Search the relocation related .text section */
1681 for (i = 0; i < n; i++) {
1682 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1683 if (strcmp(p, ".text") == 0) {
1684 /* OK, get the section header */
1685 scn = elf_getscn(elf, shndx);
1686 if (!scn)
1687 return -ENOENT;
1688 shdr = gelf_getshdr(scn, &mem);
1689 if (!shdr)
1690 return -ENOENT;
1691 *offs = shdr->sh_addr;
1692 if (adjust_offset)
1693 *offs -= shdr->sh_offset;
1694 }
1695 }
1696 return 0;
1697 }
1698
1699 /* Reverse search */
1700 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1701 struct perf_probe_point *ppt)
1702 {
1703 Dwarf_Die cudie, spdie, indie;
1704 Dwarf_Addr _addr = 0, baseaddr = 0;
1705 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1706 int baseline = 0, lineno = 0, ret = 0;
1707
1708 /* We always need to relocate the address for aranges */
1709 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1710 addr += baseaddr;
1711 /* Find cu die */
1712 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1713 pr_warning("Failed to find debug information for address %lx\n",
1714 addr);
1715 ret = -EINVAL;
1716 goto end;
1717 }
1718
1719 /* Find a corresponding line (filename and lineno) */
1720 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1721 /* Don't care whether it failed or not */
1722
1723 /* Find a corresponding function (name, baseline and baseaddr) */
1724 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1725 /* Get function entry information */
1726 func = basefunc = dwarf_diename(&spdie);
1727 if (!func ||
1728 die_entrypc(&spdie, &baseaddr) != 0 ||
1729 dwarf_decl_line(&spdie, &baseline) != 0) {
1730 lineno = 0;
1731 goto post;
1732 }
1733
1734 fname = dwarf_decl_file(&spdie);
1735 if (addr == (unsigned long)baseaddr) {
1736 /* Function entry - Relative line number is 0 */
1737 lineno = baseline;
1738 goto post;
1739 }
1740
1741 /* Track down the inline functions step by step */
1742 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1743 &indie)) {
1744 /* There is an inline function */
1745 if (die_entrypc(&indie, &_addr) == 0 &&
1746 _addr == addr) {
1747 /*
1748 * addr is at an inline function entry.
1749 * In this case, lineno should be the call-site
1750 * line number. (overwrite lineinfo)
1751 */
1752 lineno = die_get_call_lineno(&indie);
1753 fname = die_get_call_file(&indie);
1754 break;
1755 } else {
1756 /*
1757 * addr is in an inline function body.
1758 * Since lineno points one of the lines
1759 * of the inline function, baseline should
1760 * be the entry line of the inline function.
1761 */
1762 tmp = dwarf_diename(&indie);
1763 if (!tmp ||
1764 dwarf_decl_line(&indie, &baseline) != 0)
1765 break;
1766 func = tmp;
1767 spdie = indie;
1768 }
1769 }
1770 /* Verify the lineno and baseline are in a same file */
1771 tmp = dwarf_decl_file(&spdie);
1772 if (!tmp || strcmp(tmp, fname) != 0)
1773 lineno = 0;
1774 }
1775
1776 post:
1777 /* Make a relative line number or an offset */
1778 if (lineno)
1779 ppt->line = lineno - baseline;
1780 else if (basefunc) {
1781 ppt->offset = addr - (unsigned long)baseaddr;
1782 func = basefunc;
1783 }
1784
1785 /* Duplicate strings */
1786 if (func) {
1787 ppt->function = strdup(func);
1788 if (ppt->function == NULL) {
1789 ret = -ENOMEM;
1790 goto end;
1791 }
1792 }
1793 if (fname) {
1794 ppt->file = strdup(fname);
1795 if (ppt->file == NULL) {
1796 zfree(&ppt->function);
1797 ret = -ENOMEM;
1798 goto end;
1799 }
1800 }
1801 end:
1802 if (ret == 0 && (fname || func))
1803 ret = 1; /* Found a point */
1804 return ret;
1805 }
1806
1807 /* Add a line and store the src path */
1808 static int line_range_add_line(const char *src, unsigned int lineno,
1809 struct line_range *lr)
1810 {
1811 /* Copy source path */
1812 if (!lr->path) {
1813 lr->path = strdup(src);
1814 if (lr->path == NULL)
1815 return -ENOMEM;
1816 }
1817 return intlist__add(lr->line_list, lineno);
1818 }
1819
1820 static int line_range_walk_cb(const char *fname, int lineno,
1821 Dwarf_Addr addr __maybe_unused,
1822 void *data)
1823 {
1824 struct line_finder *lf = data;
1825 const char *__fname;
1826 int __lineno;
1827 int err;
1828
1829 if ((strtailcmp(fname, lf->fname) != 0) ||
1830 (lf->lno_s > lineno || lf->lno_e < lineno))
1831 return 0;
1832
1833 /* Make sure this line can be reversable */
1834 if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
1835 && (lineno != __lineno || strcmp(fname, __fname)))
1836 return 0;
1837
1838 err = line_range_add_line(fname, lineno, lf->lr);
1839 if (err < 0 && err != -EEXIST)
1840 return err;
1841
1842 return 0;
1843 }
1844
1845 /* Find line range from its line number */
1846 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1847 {
1848 int ret;
1849
1850 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1851
1852 /* Update status */
1853 if (ret >= 0)
1854 if (!intlist__empty(lf->lr->line_list))
1855 ret = lf->found = 1;
1856 else
1857 ret = 0; /* Lines are not found */
1858 else {
1859 zfree(&lf->lr->path);
1860 }
1861 return ret;
1862 }
1863
1864 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1865 {
1866 int ret = find_line_range_by_line(in_die, data);
1867
1868 /*
1869 * We have to check all instances of inlined function, because
1870 * some execution paths can be optimized out depends on the
1871 * function argument of instances. However, if an error occurs,
1872 * it should be handled by the caller.
1873 */
1874 return ret < 0 ? ret : 0;
1875 }
1876
1877 /* Search function definition from function name */
1878 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1879 {
1880 struct dwarf_callback_param *param = data;
1881 struct line_finder *lf = param->data;
1882 struct line_range *lr = lf->lr;
1883
1884 /* Check declared file */
1885 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1886 return DWARF_CB_OK;
1887
1888 if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
1889 lf->fname = dwarf_decl_file(sp_die);
1890 dwarf_decl_line(sp_die, &lr->offset);
1891 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1892 lf->lno_s = lr->offset + lr->start;
1893 if (lf->lno_s < 0) /* Overflow */
1894 lf->lno_s = INT_MAX;
1895 lf->lno_e = lr->offset + lr->end;
1896 if (lf->lno_e < 0) /* Overflow */
1897 lf->lno_e = INT_MAX;
1898 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1899 lr->start = lf->lno_s;
1900 lr->end = lf->lno_e;
1901 if (!die_is_func_instance(sp_die))
1902 param->retval = die_walk_instances(sp_die,
1903 line_range_inline_cb, lf);
1904 else
1905 param->retval = find_line_range_by_line(sp_die, lf);
1906 return DWARF_CB_ABORT;
1907 }
1908 return DWARF_CB_OK;
1909 }
1910
1911 static int find_line_range_by_func(struct line_finder *lf)
1912 {
1913 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1914 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1915 return param.retval;
1916 }
1917
1918 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1919 {
1920 struct line_finder lf = {.lr = lr, .found = 0};
1921 int ret = 0;
1922 Dwarf_Off off = 0, noff;
1923 size_t cuhl;
1924 Dwarf_Die *diep;
1925 const char *comp_dir;
1926
1927 /* Fastpath: lookup by function name from .debug_pubnames section */
1928 if (lr->function) {
1929 struct pubname_callback_param pubname_param = {
1930 .function = lr->function, .file = lr->file,
1931 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1932 struct dwarf_callback_param line_range_param = {
1933 .data = (void *)&lf, .retval = 0};
1934
1935 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1936 &pubname_param, 0);
1937 if (pubname_param.found) {
1938 line_range_search_cb(&lf.sp_die, &line_range_param);
1939 if (lf.found)
1940 goto found;
1941 }
1942 }
1943
1944 /* Loop on CUs (Compilation Unit) */
1945 while (!lf.found && ret >= 0) {
1946 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1947 NULL, NULL, NULL) != 0)
1948 break;
1949
1950 /* Get the DIE(Debugging Information Entry) of this CU */
1951 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1952 if (!diep)
1953 continue;
1954
1955 /* Check if target file is included. */
1956 if (lr->file)
1957 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1958 else
1959 lf.fname = 0;
1960
1961 if (!lr->file || lf.fname) {
1962 if (lr->function)
1963 ret = find_line_range_by_func(&lf);
1964 else {
1965 lf.lno_s = lr->start;
1966 lf.lno_e = lr->end;
1967 ret = find_line_range_by_line(NULL, &lf);
1968 }
1969 }
1970 off = noff;
1971 }
1972
1973 found:
1974 /* Store comp_dir */
1975 if (lf.found) {
1976 comp_dir = cu_get_comp_dir(&lf.cu_die);
1977 if (comp_dir) {
1978 lr->comp_dir = strdup(comp_dir);
1979 if (!lr->comp_dir)
1980 ret = -ENOMEM;
1981 }
1982 }
1983
1984 pr_debug("path: %s\n", lr->path);
1985 return (ret < 0) ? ret : lf.found;
1986 }
1987
1988 #ifdef HAVE_DEBUGINFOD_SUPPORT
1989 /* debuginfod doesn't require the comp_dir but buildid is required */
1990 static int get_source_from_debuginfod(const char *raw_path,
1991 const char *sbuild_id, char **new_path)
1992 {
1993 debuginfod_client *c = debuginfod_begin();
1994 const char *p = raw_path;
1995 int fd;
1996
1997 if (!c)
1998 return -ENOMEM;
1999
2000 fd = debuginfod_find_source(c, (const unsigned char *)sbuild_id,
2001 0, p, new_path);
2002 pr_debug("Search %s from debuginfod -> %d\n", p, fd);
2003 if (fd >= 0)
2004 close(fd);
2005 debuginfod_end(c);
2006 if (fd < 0) {
2007 pr_debug("Failed to find %s in debuginfod (%s)\n",
2008 raw_path, sbuild_id);
2009 return -ENOENT;
2010 }
2011 pr_debug("Got a source %s\n", *new_path);
2012
2013 return 0;
2014 }
2015 #else
2016 static inline int get_source_from_debuginfod(const char *raw_path __maybe_unused,
2017 const char *sbuild_id __maybe_unused,
2018 char **new_path __maybe_unused)
2019 {
2020 return -ENOTSUP;
2021 }
2022 #endif
2023 /*
2024 * Find a src file from a DWARF tag path. Prepend optional source path prefix
2025 * and chop off leading directories that do not exist. Result is passed back as
2026 * a newly allocated path on success.
2027 * Return 0 if file was found and readable, -errno otherwise.
2028 */
2029 int find_source_path(const char *raw_path, const char *sbuild_id,
2030 const char *comp_dir, char **new_path)
2031 {
2032 const char *prefix = symbol_conf.source_prefix;
2033
2034 if (sbuild_id && !prefix) {
2035 if (!get_source_from_debuginfod(raw_path, sbuild_id, new_path))
2036 return 0;
2037 }
2038
2039 if (!prefix) {
2040 if (raw_path[0] != '/' && comp_dir)
2041 /* If not an absolute path, try to use comp_dir */
2042 prefix = comp_dir;
2043 else {
2044 if (access(raw_path, R_OK) == 0) {
2045 *new_path = strdup(raw_path);
2046 return *new_path ? 0 : -ENOMEM;
2047 } else
2048 return -errno;
2049 }
2050 }
2051
2052 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
2053 if (!*new_path)
2054 return -ENOMEM;
2055
2056 for (;;) {
2057 sprintf(*new_path, "%s/%s", prefix, raw_path);
2058
2059 if (access(*new_path, R_OK) == 0)
2060 return 0;
2061
2062 if (!symbol_conf.source_prefix) {
2063 /* In case of searching comp_dir, don't retry */
2064 zfree(new_path);
2065 return -errno;
2066 }
2067
2068 switch (errno) {
2069 case ENAMETOOLONG:
2070 case ENOENT:
2071 case EROFS:
2072 case EFAULT:
2073 raw_path = strchr(++raw_path, '/');
2074 if (!raw_path) {
2075 zfree(new_path);
2076 return -ENOENT;
2077 }
2078 continue;
2079
2080 default:
2081 zfree(new_path);
2082 return -errno;
2083 }
2084 }
2085 }
Linux with added FPC-III support