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