GNU Linux-libre 4.19.211-gnu1
[releases.git] / tools / perf / util / probe-finder.c
1 /*
2  * probe-finder.c : C expression to kprobe event converter
3  *
4  * Written by Masami Hiramatsu <mhiramat@redhat.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19  *
20  */
21
22 #include <inttypes.h>
23 #include <sys/utsname.h>
24 #include <sys/types.h>
25 #include <sys/stat.h>
26 #include <fcntl.h>
27 #include <errno.h>
28 #include <stdio.h>
29 #include <unistd.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <stdarg.h>
33 #include <dwarf-regs.h>
34
35 #include <linux/bitops.h>
36 #include "event.h"
37 #include "dso.h"
38 #include "debug.h"
39 #include "intlist.h"
40 #include "util.h"
41 #include "strlist.h"
42 #include "symbol.h"
43 #include "probe-finder.h"
44 #include "probe-file.h"
45 #include "string2.h"
46
47 /* Kprobe tracer basic type is up to u64 */
48 #define MAX_BASIC_TYPE_BITS     64
49
50 /* Dwarf FL wrappers */
51 static char *debuginfo_path;    /* Currently dummy */
52
53 static const Dwfl_Callbacks offline_callbacks = {
54         .find_debuginfo = dwfl_standard_find_debuginfo,
55         .debuginfo_path = &debuginfo_path,
56
57         .section_address = dwfl_offline_section_address,
58
59         /* We use this table for core files too.  */
60         .find_elf = dwfl_build_id_find_elf,
61 };
62
63 /* Get a Dwarf from offline image */
64 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
65                                          const char *path)
66 {
67         int fd;
68
69         fd = open(path, O_RDONLY);
70         if (fd < 0)
71                 return fd;
72
73         dbg->dwfl = dwfl_begin(&offline_callbacks);
74         if (!dbg->dwfl)
75                 goto error;
76
77         dwfl_report_begin(dbg->dwfl);
78         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
79         if (!dbg->mod)
80                 goto error;
81
82         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
83         if (!dbg->dbg)
84                 goto error;
85
86         dwfl_report_end(dbg->dwfl, NULL, NULL);
87
88         return 0;
89 error:
90         if (dbg->dwfl)
91                 dwfl_end(dbg->dwfl);
92         else
93                 close(fd);
94         memset(dbg, 0, sizeof(*dbg));
95
96         return -ENOENT;
97 }
98
99 static struct debuginfo *__debuginfo__new(const char *path)
100 {
101         struct debuginfo *dbg = zalloc(sizeof(*dbg));
102         if (!dbg)
103                 return NULL;
104
105         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
106                 zfree(&dbg);
107         if (dbg)
108                 pr_debug("Open Debuginfo file: %s\n", path);
109         return dbg;
110 }
111
112 enum dso_binary_type distro_dwarf_types[] = {
113         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
114         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
115         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
116         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
117         DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO,
118         DSO_BINARY_TYPE__NOT_FOUND,
119 };
120
121 struct debuginfo *debuginfo__new(const char *path)
122 {
123         enum dso_binary_type *type;
124         char buf[PATH_MAX], nil = '\0';
125         struct dso *dso;
126         struct debuginfo *dinfo = NULL;
127
128         /* Try to open distro debuginfo files */
129         dso = dso__new(path);
130         if (!dso)
131                 goto out;
132
133         for (type = distro_dwarf_types;
134              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
135              type++) {
136                 if (dso__read_binary_type_filename(dso, *type, &nil,
137                                                    buf, PATH_MAX) < 0)
138                         continue;
139                 dinfo = __debuginfo__new(buf);
140         }
141         dso__put(dso);
142
143 out:
144         /* if failed to open all distro debuginfo, open given binary */
145         return dinfo ? : __debuginfo__new(path);
146 }
147
148 void debuginfo__delete(struct debuginfo *dbg)
149 {
150         if (dbg) {
151                 if (dbg->dwfl)
152                         dwfl_end(dbg->dwfl);
153                 free(dbg);
154         }
155 }
156
157 /*
158  * Probe finder related functions
159  */
160
161 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
162 {
163         struct probe_trace_arg_ref *ref;
164         ref = zalloc(sizeof(struct probe_trace_arg_ref));
165         if (ref != NULL)
166                 ref->offset = offs;
167         return ref;
168 }
169
170 /*
171  * Convert a location into trace_arg.
172  * If tvar == NULL, this just checks variable can be converted.
173  * If fentry == true and vr_die is a parameter, do huristic search
174  * for the location fuzzed by function entry mcount.
175  */
176 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
177                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
178                                      unsigned int machine,
179                                      struct probe_trace_arg *tvar)
180 {
181         Dwarf_Attribute attr;
182         Dwarf_Addr tmp = 0;
183         Dwarf_Op *op;
184         size_t nops;
185         unsigned int regn;
186         Dwarf_Word offs = 0;
187         bool ref = false;
188         const char *regs;
189         int ret, ret2 = 0;
190
191         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
192                 goto static_var;
193
194         /* TODO: handle more than 1 exprs */
195         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
196                 return -EINVAL; /* Broken DIE ? */
197         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
198                 ret = dwarf_entrypc(sp_die, &tmp);
199                 if (ret)
200                         return -ENOENT;
201
202                 if (probe_conf.show_location_range &&
203                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
204                         ret2 = -ERANGE;
205                 } else if (addr != tmp ||
206                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
207                         return -ENOENT;
208                 }
209
210                 ret = dwarf_highpc(sp_die, &tmp);
211                 if (ret)
212                         return -ENOENT;
213                 /*
214                  * This is fuzzed by fentry mcount. We try to find the
215                  * parameter location at the earliest address.
216                  */
217                 for (addr += 1; addr <= tmp; addr++) {
218                         if (dwarf_getlocation_addr(&attr, addr, &op,
219                                                    &nops, 1) > 0)
220                                 goto found;
221                 }
222                 return -ENOENT;
223         }
224 found:
225         if (nops == 0)
226                 /* TODO: Support const_value */
227                 return -ENOENT;
228
229         if (op->atom == DW_OP_addr) {
230 static_var:
231                 if (!tvar)
232                         return ret2;
233                 /* Static variables on memory (not stack), make @varname */
234                 ret = strlen(dwarf_diename(vr_die));
235                 tvar->value = zalloc(ret + 2);
236                 if (tvar->value == NULL)
237                         return -ENOMEM;
238                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
239                 tvar->ref = alloc_trace_arg_ref((long)offs);
240                 if (tvar->ref == NULL)
241                         return -ENOMEM;
242                 return ret2;
243         }
244
245         /* If this is based on frame buffer, set the offset */
246         if (op->atom == DW_OP_fbreg) {
247                 if (fb_ops == NULL)
248                         return -ENOTSUP;
249                 ref = true;
250                 offs = op->number;
251                 op = &fb_ops[0];
252         }
253
254         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
255                 regn = op->atom - DW_OP_breg0;
256                 offs += op->number;
257                 ref = true;
258         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
259                 regn = op->atom - DW_OP_reg0;
260         } else if (op->atom == DW_OP_bregx) {
261                 regn = op->number;
262                 offs += op->number2;
263                 ref = true;
264         } else if (op->atom == DW_OP_regx) {
265                 regn = op->number;
266         } else {
267                 pr_debug("DW_OP %x is not supported.\n", op->atom);
268                 return -ENOTSUP;
269         }
270
271         if (!tvar)
272                 return ret2;
273
274         regs = get_dwarf_regstr(regn, machine);
275         if (!regs) {
276                 /* This should be a bug in DWARF or this tool */
277                 pr_warning("Mapping for the register number %u "
278                            "missing on this architecture.\n", regn);
279                 return -ENOTSUP;
280         }
281
282         tvar->value = strdup(regs);
283         if (tvar->value == NULL)
284                 return -ENOMEM;
285
286         if (ref) {
287                 tvar->ref = alloc_trace_arg_ref((long)offs);
288                 if (tvar->ref == NULL)
289                         return -ENOMEM;
290         }
291         return ret2;
292 }
293
294 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
295
296 static int convert_variable_type(Dwarf_Die *vr_die,
297                                  struct probe_trace_arg *tvar,
298                                  const char *cast)
299 {
300         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
301         Dwarf_Die type;
302         char buf[16];
303         char sbuf[STRERR_BUFSIZE];
304         int bsize, boffs, total;
305         int ret;
306         char prefix;
307
308         /* TODO: check all types */
309         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
310             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
311                 /* Non string type is OK */
312                 /* and respect signedness/hexadecimal cast */
313                 tvar->type = strdup(cast);
314                 return (tvar->type == NULL) ? -ENOMEM : 0;
315         }
316
317         bsize = dwarf_bitsize(vr_die);
318         if (bsize > 0) {
319                 /* This is a bitfield */
320                 boffs = dwarf_bitoffset(vr_die);
321                 total = dwarf_bytesize(vr_die);
322                 if (boffs < 0 || total < 0)
323                         return -ENOENT;
324                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
325                                 BYTES_TO_BITS(total));
326                 goto formatted;
327         }
328
329         if (die_get_real_type(vr_die, &type) == NULL) {
330                 pr_warning("Failed to get a type information of %s.\n",
331                            dwarf_diename(vr_die));
332                 return -ENOENT;
333         }
334
335         pr_debug("%s type is %s.\n",
336                  dwarf_diename(vr_die), dwarf_diename(&type));
337
338         if (cast && strcmp(cast, "string") == 0) {      /* String type */
339                 ret = dwarf_tag(&type);
340                 if (ret != DW_TAG_pointer_type &&
341                     ret != DW_TAG_array_type) {
342                         pr_warning("Failed to cast into string: "
343                                    "%s(%s) is not a pointer nor array.\n",
344                                    dwarf_diename(vr_die), dwarf_diename(&type));
345                         return -EINVAL;
346                 }
347                 if (die_get_real_type(&type, &type) == NULL) {
348                         pr_warning("Failed to get a type"
349                                    " information.\n");
350                         return -ENOENT;
351                 }
352                 if (ret == DW_TAG_pointer_type) {
353                         while (*ref_ptr)
354                                 ref_ptr = &(*ref_ptr)->next;
355                         /* Add new reference with offset +0 */
356                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
357                         if (*ref_ptr == NULL) {
358                                 pr_warning("Out of memory error\n");
359                                 return -ENOMEM;
360                         }
361                 }
362                 if (!die_compare_name(&type, "char") &&
363                     !die_compare_name(&type, "unsigned char")) {
364                         pr_warning("Failed to cast into string: "
365                                    "%s is not (unsigned) char *.\n",
366                                    dwarf_diename(vr_die));
367                         return -EINVAL;
368                 }
369                 tvar->type = strdup(cast);
370                 return (tvar->type == NULL) ? -ENOMEM : 0;
371         }
372
373         if (cast && (strcmp(cast, "u") == 0))
374                 prefix = 'u';
375         else if (cast && (strcmp(cast, "s") == 0))
376                 prefix = 's';
377         else if (cast && (strcmp(cast, "x") == 0) &&
378                  probe_type_is_available(PROBE_TYPE_X))
379                 prefix = 'x';
380         else
381                 prefix = die_is_signed_type(&type) ? 's' :
382                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
383
384         ret = dwarf_bytesize(&type);
385         if (ret <= 0)
386                 /* No size ... try to use default type */
387                 return 0;
388         ret = BYTES_TO_BITS(ret);
389
390         /* Check the bitwidth */
391         if (ret > MAX_BASIC_TYPE_BITS) {
392                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
393                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
394                 ret = MAX_BASIC_TYPE_BITS;
395         }
396         ret = snprintf(buf, 16, "%c%d", prefix, ret);
397
398 formatted:
399         if (ret < 0 || ret >= 16) {
400                 if (ret >= 16)
401                         ret = -E2BIG;
402                 pr_warning("Failed to convert variable type: %s\n",
403                            str_error_r(-ret, sbuf, sizeof(sbuf)));
404                 return ret;
405         }
406         tvar->type = strdup(buf);
407         if (tvar->type == NULL)
408                 return -ENOMEM;
409         return 0;
410 }
411
412 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
413                                     struct perf_probe_arg_field *field,
414                                     struct probe_trace_arg_ref **ref_ptr,
415                                     Dwarf_Die *die_mem)
416 {
417         struct probe_trace_arg_ref *ref = *ref_ptr;
418         Dwarf_Die type;
419         Dwarf_Word offs;
420         int ret, tag;
421
422         pr_debug("converting %s in %s\n", field->name, varname);
423         if (die_get_real_type(vr_die, &type) == NULL) {
424                 pr_warning("Failed to get the type of %s.\n", varname);
425                 return -ENOENT;
426         }
427         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
428                   (unsigned)dwarf_dieoffset(&type));
429         tag = dwarf_tag(&type);
430
431         if (field->name[0] == '[' &&
432             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
433                 /* Save original type for next field or type */
434                 memcpy(die_mem, &type, sizeof(*die_mem));
435                 /* Get the type of this array */
436                 if (die_get_real_type(&type, &type) == NULL) {
437                         pr_warning("Failed to get the type of %s.\n", varname);
438                         return -ENOENT;
439                 }
440                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
441                          (unsigned)dwarf_dieoffset(&type));
442                 if (tag == DW_TAG_pointer_type) {
443                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
444                         if (ref == NULL)
445                                 return -ENOMEM;
446                         if (*ref_ptr)
447                                 (*ref_ptr)->next = ref;
448                         else
449                                 *ref_ptr = ref;
450                 }
451                 ref->offset += dwarf_bytesize(&type) * field->index;
452                 goto next;
453         } else if (tag == DW_TAG_pointer_type) {
454                 /* Check the pointer and dereference */
455                 if (!field->ref) {
456                         pr_err("Semantic error: %s must be referred by '->'\n",
457                                field->name);
458                         return -EINVAL;
459                 }
460                 /* Get the type pointed by this pointer */
461                 if (die_get_real_type(&type, &type) == NULL) {
462                         pr_warning("Failed to get the type of %s.\n", varname);
463                         return -ENOENT;
464                 }
465                 /* Verify it is a data structure  */
466                 tag = dwarf_tag(&type);
467                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
468                         pr_warning("%s is not a data structure nor a union.\n",
469                                    varname);
470                         return -EINVAL;
471                 }
472
473                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
474                 if (ref == NULL)
475                         return -ENOMEM;
476                 if (*ref_ptr)
477                         (*ref_ptr)->next = ref;
478                 else
479                         *ref_ptr = ref;
480         } else {
481                 /* Verify it is a data structure  */
482                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
483                         pr_warning("%s is not a data structure nor a union.\n",
484                                    varname);
485                         return -EINVAL;
486                 }
487                 if (field->name[0] == '[') {
488                         pr_err("Semantic error: %s is not a pointer"
489                                " nor array.\n", varname);
490                         return -EINVAL;
491                 }
492                 /* While prcessing unnamed field, we don't care about this */
493                 if (field->ref && dwarf_diename(vr_die)) {
494                         pr_err("Semantic error: %s must be referred by '.'\n",
495                                field->name);
496                         return -EINVAL;
497                 }
498                 if (!ref) {
499                         pr_warning("Structure on a register is not "
500                                    "supported yet.\n");
501                         return -ENOTSUP;
502                 }
503         }
504
505         if (die_find_member(&type, field->name, die_mem) == NULL) {
506                 pr_warning("%s(type:%s) has no member %s.\n", varname,
507                            dwarf_diename(&type), field->name);
508                 return -EINVAL;
509         }
510
511         /* Get the offset of the field */
512         if (tag == DW_TAG_union_type) {
513                 offs = 0;
514         } else {
515                 ret = die_get_data_member_location(die_mem, &offs);
516                 if (ret < 0) {
517                         pr_warning("Failed to get the offset of %s.\n",
518                                    field->name);
519                         return ret;
520                 }
521         }
522         ref->offset += (long)offs;
523
524         /* If this member is unnamed, we need to reuse this field */
525         if (!dwarf_diename(die_mem))
526                 return convert_variable_fields(die_mem, varname, field,
527                                                 &ref, die_mem);
528
529 next:
530         /* Converting next field */
531         if (field->next)
532                 return convert_variable_fields(die_mem, field->name,
533                                         field->next, &ref, die_mem);
534         else
535                 return 0;
536 }
537
538 /* Show a variables in kprobe event format */
539 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
540 {
541         Dwarf_Die die_mem;
542         int ret;
543
544         pr_debug("Converting variable %s into trace event.\n",
545                  dwarf_diename(vr_die));
546
547         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
548                                         &pf->sp_die, pf->machine, pf->tvar);
549         if (ret == -ENOENT || ret == -EINVAL) {
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                        pf->pvar->var, pf->pvar->var);
554         } else if (ret == -ENOTSUP)
555                 pr_err("Sorry, we don't support this variable location yet.\n");
556         else if (ret == 0 && pf->pvar->field) {
557                 ret = convert_variable_fields(vr_die, pf->pvar->var,
558                                               pf->pvar->field, &pf->tvar->ref,
559                                               &die_mem);
560                 vr_die = &die_mem;
561         }
562         if (ret == 0)
563                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
564         /* *expr will be cached in libdw. Don't free it. */
565         return ret;
566 }
567
568 /* Find a variable in a scope DIE */
569 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
570 {
571         Dwarf_Die vr_die;
572         char *buf, *ptr;
573         int ret = 0;
574
575         /* Copy raw parameters */
576         if (!is_c_varname(pf->pvar->var))
577                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
578
579         if (pf->pvar->name)
580                 pf->tvar->name = strdup(pf->pvar->name);
581         else {
582                 buf = synthesize_perf_probe_arg(pf->pvar);
583                 if (!buf)
584                         return -ENOMEM;
585                 ptr = strchr(buf, ':'); /* Change type separator to _ */
586                 if (ptr)
587                         *ptr = '_';
588                 pf->tvar->name = buf;
589         }
590         if (pf->tvar->name == NULL)
591                 return -ENOMEM;
592
593         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
594         /* Search child die for local variables and parameters. */
595         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
596                 /* Search again in global variables */
597                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
598                                                 0, &vr_die)) {
599                         pr_warning("Failed to find '%s' in this function.\n",
600                                    pf->pvar->var);
601                         ret = -ENOENT;
602                 }
603         }
604         if (ret >= 0)
605                 ret = convert_variable(&vr_die, pf);
606
607         return ret;
608 }
609
610 /* Convert subprogram DIE to trace point */
611 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
612                                   Dwarf_Addr paddr, bool retprobe,
613                                   const char *function,
614                                   struct probe_trace_point *tp)
615 {
616         Dwarf_Addr eaddr;
617         GElf_Sym sym;
618         const char *symbol;
619
620         /* Verify the address is correct */
621         if (!dwarf_haspc(sp_die, paddr)) {
622                 pr_warning("Specified offset is out of %s\n",
623                            dwarf_diename(sp_die));
624                 return -EINVAL;
625         }
626
627         if (dwarf_entrypc(sp_die, &eaddr) == 0) {
628                 /* If the DIE has entrypc, use it. */
629                 symbol = dwarf_diename(sp_die);
630         } else {
631                 /* Try to get actual symbol name and address from symtab */
632                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
633                 eaddr = sym.st_value;
634         }
635         if (!symbol) {
636                 pr_warning("Failed to find symbol at 0x%lx\n",
637                            (unsigned long)paddr);
638                 return -ENOENT;
639         }
640
641         tp->offset = (unsigned long)(paddr - eaddr);
642         tp->address = (unsigned long)paddr;
643         tp->symbol = strdup(symbol);
644         if (!tp->symbol)
645                 return -ENOMEM;
646
647         /* Return probe must be on the head of a subprogram */
648         if (retprobe) {
649                 if (eaddr != paddr) {
650                         pr_warning("Failed to find \"%s%%return\",\n"
651                                    " because %s is an inlined function and"
652                                    " has no return point.\n", function,
653                                    function);
654                         return -EINVAL;
655                 }
656                 tp->retprobe = true;
657         }
658
659         return 0;
660 }
661
662 /* Call probe_finder callback with scope DIE */
663 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
664 {
665         Dwarf_Attribute fb_attr;
666         Dwarf_Frame *frame = NULL;
667         size_t nops;
668         int ret;
669
670         if (!sc_die) {
671                 pr_err("Caller must pass a scope DIE. Program error.\n");
672                 return -EINVAL;
673         }
674
675         /* If not a real subprogram, find a real one */
676         if (!die_is_func_def(sc_die)) {
677                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
678                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
679                                 pr_warning("Ignoring tail call from %s\n",
680                                                 dwarf_diename(&pf->sp_die));
681                                 return 0;
682                         } else {
683                                 pr_warning("Failed to find probe point in any "
684                                            "functions.\n");
685                                 return -ENOENT;
686                         }
687                 }
688         } else
689                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
690
691         /* Get the frame base attribute/ops from subprogram */
692         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
693         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
694         if (ret <= 0 || nops == 0) {
695                 pf->fb_ops = NULL;
696 #if _ELFUTILS_PREREQ(0, 142)
697         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
698                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
699                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
700                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
701                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
702                         pr_warning("Failed to get call frame on 0x%jx\n",
703                                    (uintmax_t)pf->addr);
704                         free(frame);
705                         return -ENOENT;
706                 }
707 #endif
708         }
709
710         /* Call finder's callback handler */
711         ret = pf->callback(sc_die, pf);
712
713         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
714         free(frame);
715         pf->fb_ops = NULL;
716
717         return ret;
718 }
719
720 struct find_scope_param {
721         const char *function;
722         const char *file;
723         int line;
724         int diff;
725         Dwarf_Die *die_mem;
726         bool found;
727 };
728
729 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
730 {
731         struct find_scope_param *fsp = data;
732         const char *file;
733         int lno;
734
735         /* Skip if declared file name does not match */
736         if (fsp->file) {
737                 file = dwarf_decl_file(fn_die);
738                 if (!file || strcmp(fsp->file, file) != 0)
739                         return 0;
740         }
741         /* If the function name is given, that's what user expects */
742         if (fsp->function) {
743                 if (die_match_name(fn_die, fsp->function)) {
744                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
745                         fsp->found = true;
746                         return 1;
747                 }
748         } else {
749                 /* With the line number, find the nearest declared DIE */
750                 dwarf_decl_line(fn_die, &lno);
751                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
752                         /* Keep a candidate and continue */
753                         fsp->diff = fsp->line - lno;
754                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
755                         fsp->found = true;
756                 }
757         }
758         return 0;
759 }
760
761 /* Return innermost DIE */
762 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
763 {
764         struct find_scope_param *fsp = data;
765
766         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
767         fsp->found = true;
768         return 1;
769 }
770
771 /* Find an appropriate scope fits to given conditions */
772 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
773 {
774         struct find_scope_param fsp = {
775                 .function = pf->pev->point.function,
776                 .file = pf->fname,
777                 .line = pf->lno,
778                 .diff = INT_MAX,
779                 .die_mem = die_mem,
780                 .found = false,
781         };
782         int ret;
783
784         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
785                                    &fsp);
786         if (!ret && !fsp.found)
787                 cu_walk_functions_at(&pf->cu_die, pf->addr,
788                                      find_inner_scope_cb, &fsp);
789
790         return fsp.found ? die_mem : NULL;
791 }
792
793 static int probe_point_line_walker(const char *fname, int lineno,
794                                    Dwarf_Addr addr, void *data)
795 {
796         struct probe_finder *pf = data;
797         Dwarf_Die *sc_die, die_mem;
798         int ret;
799
800         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
801                 return 0;
802
803         pf->addr = addr;
804         sc_die = find_best_scope(pf, &die_mem);
805         if (!sc_die) {
806                 pr_warning("Failed to find scope of probe point.\n");
807                 return -ENOENT;
808         }
809
810         ret = call_probe_finder(sc_die, pf);
811
812         /* Continue if no error, because the line will be in inline function */
813         return ret < 0 ? ret : 0;
814 }
815
816 /* Find probe point from its line number */
817 static int find_probe_point_by_line(struct probe_finder *pf)
818 {
819         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
820 }
821
822 /* Find lines which match lazy pattern */
823 static int find_lazy_match_lines(struct intlist *list,
824                                  const char *fname, const char *pat)
825 {
826         FILE *fp;
827         char *line = NULL;
828         size_t line_len;
829         ssize_t len;
830         int count = 0, linenum = 1;
831         char sbuf[STRERR_BUFSIZE];
832
833         fp = fopen(fname, "r");
834         if (!fp) {
835                 pr_warning("Failed to open %s: %s\n", fname,
836                            str_error_r(errno, sbuf, sizeof(sbuf)));
837                 return -errno;
838         }
839
840         while ((len = getline(&line, &line_len, fp)) > 0) {
841
842                 if (line[len - 1] == '\n')
843                         line[len - 1] = '\0';
844
845                 if (strlazymatch(line, pat)) {
846                         intlist__add(list, linenum);
847                         count++;
848                 }
849                 linenum++;
850         }
851
852         if (ferror(fp))
853                 count = -errno;
854         free(line);
855         fclose(fp);
856
857         if (count == 0)
858                 pr_debug("No matched lines found in %s.\n", fname);
859         return count;
860 }
861
862 static int probe_point_lazy_walker(const char *fname, int lineno,
863                                    Dwarf_Addr addr, void *data)
864 {
865         struct probe_finder *pf = data;
866         Dwarf_Die *sc_die, die_mem;
867         int ret;
868
869         if (!intlist__has_entry(pf->lcache, lineno) ||
870             strtailcmp(fname, pf->fname) != 0)
871                 return 0;
872
873         pr_debug("Probe line found: line:%d addr:0x%llx\n",
874                  lineno, (unsigned long long)addr);
875         pf->addr = addr;
876         pf->lno = lineno;
877         sc_die = find_best_scope(pf, &die_mem);
878         if (!sc_die) {
879                 pr_warning("Failed to find scope of probe point.\n");
880                 return -ENOENT;
881         }
882
883         ret = call_probe_finder(sc_die, pf);
884
885         /*
886          * Continue if no error, because the lazy pattern will match
887          * to other lines
888          */
889         return ret < 0 ? ret : 0;
890 }
891
892 /* Find probe points from lazy pattern  */
893 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
894 {
895         int ret = 0;
896         char *fpath;
897
898         if (intlist__empty(pf->lcache)) {
899                 const char *comp_dir;
900
901                 comp_dir = cu_get_comp_dir(&pf->cu_die);
902                 ret = get_real_path(pf->fname, comp_dir, &fpath);
903                 if (ret < 0) {
904                         pr_warning("Failed to find source file path.\n");
905                         return ret;
906                 }
907
908                 /* Matching lazy line pattern */
909                 ret = find_lazy_match_lines(pf->lcache, fpath,
910                                             pf->pev->point.lazy_line);
911                 free(fpath);
912                 if (ret <= 0)
913                         return ret;
914         }
915
916         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
917 }
918
919 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
920 {
921         struct perf_probe_point *pp = &pf->pev->point;
922
923         /* Not uprobe? */
924         if (!pf->pev->uprobes)
925                 return;
926
927         /* Compiled with optimization? */
928         if (die_is_optimized_target(&pf->cu_die))
929                 return;
930
931         /* Don't know entrypc? */
932         if (!pf->addr)
933                 return;
934
935         /* Only FUNC and FUNC@SRC are eligible. */
936         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
937             pp->offset || pp->abs_address)
938                 return;
939
940         /* Not interested in func parameter? */
941         if (!perf_probe_with_var(pf->pev))
942                 return;
943
944         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
945                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
946                 pf->addr);
947
948         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
949 }
950
951 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
952 {
953         struct probe_finder *pf = data;
954         struct perf_probe_point *pp = &pf->pev->point;
955         Dwarf_Addr addr;
956         int ret;
957
958         if (pp->lazy_line)
959                 ret = find_probe_point_lazy(in_die, pf);
960         else {
961                 /* Get probe address */
962                 if (die_entrypc(in_die, &addr) != 0) {
963                         pr_warning("Failed to get entry address of %s.\n",
964                                    dwarf_diename(in_die));
965                         return -ENOENT;
966                 }
967                 if (addr == 0) {
968                         pr_debug("%s has no valid entry address. skipped.\n",
969                                  dwarf_diename(in_die));
970                         return -ENOENT;
971                 }
972                 pf->addr = addr;
973                 pf->addr += pp->offset;
974                 pr_debug("found inline addr: 0x%jx\n",
975                          (uintmax_t)pf->addr);
976
977                 ret = call_probe_finder(in_die, pf);
978         }
979
980         return ret;
981 }
982
983 /* Callback parameter with return value for libdw */
984 struct dwarf_callback_param {
985         void *data;
986         int retval;
987 };
988
989 /* Search function from function name */
990 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
991 {
992         struct dwarf_callback_param *param = data;
993         struct probe_finder *pf = param->data;
994         struct perf_probe_point *pp = &pf->pev->point;
995
996         /* Check tag and diename */
997         if (!die_is_func_def(sp_die) ||
998             !die_match_name(sp_die, pp->function))
999                 return DWARF_CB_OK;
1000
1001         /* Check declared file */
1002         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1003                 return DWARF_CB_OK;
1004
1005         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1006                  (unsigned long)dwarf_dieoffset(sp_die));
1007         pf->fname = dwarf_decl_file(sp_die);
1008         if (pp->line) { /* Function relative line */
1009                 dwarf_decl_line(sp_die, &pf->lno);
1010                 pf->lno += pp->line;
1011                 param->retval = find_probe_point_by_line(pf);
1012         } else if (die_is_func_instance(sp_die)) {
1013                 /* Instances always have the entry address */
1014                 die_entrypc(sp_die, &pf->addr);
1015                 /* But in some case the entry address is 0 */
1016                 if (pf->addr == 0) {
1017                         pr_debug("%s has no entry PC. Skipped\n",
1018                                  dwarf_diename(sp_die));
1019                         param->retval = 0;
1020                 /* Real function */
1021                 } else if (pp->lazy_line)
1022                         param->retval = find_probe_point_lazy(sp_die, pf);
1023                 else {
1024                         skip_prologue(sp_die, pf);
1025                         pf->addr += pp->offset;
1026                         /* TODO: Check the address in this function */
1027                         param->retval = call_probe_finder(sp_die, pf);
1028                 }
1029         } else if (!probe_conf.no_inlines) {
1030                 /* Inlined function: search instances */
1031                 param->retval = die_walk_instances(sp_die,
1032                                         probe_point_inline_cb, (void *)pf);
1033                 /* This could be a non-existed inline definition */
1034                 if (param->retval == -ENOENT)
1035                         param->retval = 0;
1036         }
1037
1038         /* We need to find other candidates */
1039         if (strisglob(pp->function) && param->retval >= 0) {
1040                 param->retval = 0;      /* We have to clear the result */
1041                 return DWARF_CB_OK;
1042         }
1043
1044         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1045 }
1046
1047 static int find_probe_point_by_func(struct probe_finder *pf)
1048 {
1049         struct dwarf_callback_param _param = {.data = (void *)pf,
1050                                               .retval = 0};
1051         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1052         return _param.retval;
1053 }
1054
1055 struct pubname_callback_param {
1056         char *function;
1057         char *file;
1058         Dwarf_Die *cu_die;
1059         Dwarf_Die *sp_die;
1060         int found;
1061 };
1062
1063 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1064 {
1065         struct pubname_callback_param *param = data;
1066
1067         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1068                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1069                         return DWARF_CB_OK;
1070
1071                 if (die_match_name(param->sp_die, param->function)) {
1072                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1073                                 return DWARF_CB_OK;
1074
1075                         if (param->file &&
1076                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1077                                 return DWARF_CB_OK;
1078
1079                         param->found = 1;
1080                         return DWARF_CB_ABORT;
1081                 }
1082         }
1083
1084         return DWARF_CB_OK;
1085 }
1086
1087 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1088                                   struct probe_finder *pf)
1089 {
1090         struct perf_probe_point *pp = &pf->pev->point;
1091         Dwarf_Off off, noff;
1092         size_t cuhl;
1093         Dwarf_Die *diep;
1094         int ret = 0;
1095
1096         off = 0;
1097         pf->lcache = intlist__new(NULL);
1098         if (!pf->lcache)
1099                 return -ENOMEM;
1100
1101         /* Fastpath: lookup by function name from .debug_pubnames section */
1102         if (pp->function && !strisglob(pp->function)) {
1103                 struct pubname_callback_param pubname_param = {
1104                         .function = pp->function,
1105                         .file     = pp->file,
1106                         .cu_die   = &pf->cu_die,
1107                         .sp_die   = &pf->sp_die,
1108                         .found    = 0,
1109                 };
1110                 struct dwarf_callback_param probe_param = {
1111                         .data = pf,
1112                 };
1113
1114                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1115                                   &pubname_param, 0);
1116                 if (pubname_param.found) {
1117                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1118                         if (ret)
1119                                 goto found;
1120                 }
1121         }
1122
1123         /* Loop on CUs (Compilation Unit) */
1124         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1125                 /* Get the DIE(Debugging Information Entry) of this CU */
1126                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1127                 if (!diep)
1128                         continue;
1129
1130                 /* Check if target file is included. */
1131                 if (pp->file)
1132                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1133                 else
1134                         pf->fname = NULL;
1135
1136                 if (!pp->file || pf->fname) {
1137                         if (pp->function)
1138                                 ret = find_probe_point_by_func(pf);
1139                         else if (pp->lazy_line)
1140                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1141                         else {
1142                                 pf->lno = pp->line;
1143                                 ret = find_probe_point_by_line(pf);
1144                         }
1145                         if (ret < 0)
1146                                 break;
1147                 }
1148                 off = noff;
1149         }
1150
1151 found:
1152         intlist__delete(pf->lcache);
1153         pf->lcache = NULL;
1154
1155         return ret;
1156 }
1157
1158 /* Find probe points from debuginfo */
1159 static int debuginfo__find_probes(struct debuginfo *dbg,
1160                                   struct probe_finder *pf)
1161 {
1162         int ret = 0;
1163         Elf *elf;
1164         GElf_Ehdr ehdr;
1165
1166         if (pf->cfi_eh || pf->cfi_dbg)
1167                 return debuginfo__find_probe_location(dbg, pf);
1168
1169         /* Get the call frame information from this dwarf */
1170         elf = dwarf_getelf(dbg->dbg);
1171         if (elf == NULL)
1172                 return -EINVAL;
1173
1174         if (gelf_getehdr(elf, &ehdr) == NULL)
1175                 return -EINVAL;
1176
1177         pf->machine = ehdr.e_machine;
1178
1179 #if _ELFUTILS_PREREQ(0, 142)
1180         do {
1181                 GElf_Shdr shdr;
1182
1183                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1184                     shdr.sh_type == SHT_PROGBITS)
1185                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1186
1187                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1188         } while (0);
1189 #endif
1190
1191         ret = debuginfo__find_probe_location(dbg, pf);
1192         return ret;
1193 }
1194
1195 struct local_vars_finder {
1196         struct probe_finder *pf;
1197         struct perf_probe_arg *args;
1198         bool vars;
1199         int max_args;
1200         int nargs;
1201         int ret;
1202 };
1203
1204 /* Collect available variables in this scope */
1205 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1206 {
1207         struct local_vars_finder *vf = data;
1208         struct probe_finder *pf = vf->pf;
1209         int tag;
1210
1211         tag = dwarf_tag(die_mem);
1212         if (tag == DW_TAG_formal_parameter ||
1213             (tag == DW_TAG_variable && vf->vars)) {
1214                 if (convert_variable_location(die_mem, vf->pf->addr,
1215                                               vf->pf->fb_ops, &pf->sp_die,
1216                                               pf->machine, NULL) == 0) {
1217                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1218                         if (vf->args[vf->nargs].var == NULL) {
1219                                 vf->ret = -ENOMEM;
1220                                 return DIE_FIND_CB_END;
1221                         }
1222                         pr_debug(" %s", vf->args[vf->nargs].var);
1223                         vf->nargs++;
1224                 }
1225         }
1226
1227         if (dwarf_haspc(die_mem, vf->pf->addr))
1228                 return DIE_FIND_CB_CONTINUE;
1229         else
1230                 return DIE_FIND_CB_SIBLING;
1231 }
1232
1233 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1234                              struct perf_probe_arg *args)
1235 {
1236         Dwarf_Die die_mem;
1237         int i;
1238         int n = 0;
1239         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1240                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1241
1242         for (i = 0; i < pf->pev->nargs; i++) {
1243                 /* var never be NULL */
1244                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1245                         vf.vars = true;
1246                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1247                         /* Copy normal argument */
1248                         args[n] = pf->pev->args[i];
1249                         n++;
1250                         continue;
1251                 }
1252                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1253                 vf.nargs = n;
1254                 /* Special local variables */
1255                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1256                                &die_mem);
1257                 pr_debug(" (%d)\n", vf.nargs - n);
1258                 if (vf.ret < 0)
1259                         return vf.ret;
1260                 n = vf.nargs;
1261         }
1262         return n;
1263 }
1264
1265 /* Add a found probe point into trace event list */
1266 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1267 {
1268         struct trace_event_finder *tf =
1269                         container_of(pf, struct trace_event_finder, pf);
1270         struct perf_probe_point *pp = &pf->pev->point;
1271         struct probe_trace_event *tev;
1272         struct perf_probe_arg *args = NULL;
1273         int ret, i;
1274
1275         /* Check number of tevs */
1276         if (tf->ntevs == tf->max_tevs) {
1277                 pr_warning("Too many( > %d) probe point found.\n",
1278                            tf->max_tevs);
1279                 return -ERANGE;
1280         }
1281         tev = &tf->tevs[tf->ntevs++];
1282
1283         /* Trace point should be converted from subprogram DIE */
1284         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1285                                      pp->retprobe, pp->function, &tev->point);
1286         if (ret < 0)
1287                 goto end;
1288
1289         tev->point.realname = strdup(dwarf_diename(sc_die));
1290         if (!tev->point.realname) {
1291                 ret = -ENOMEM;
1292                 goto end;
1293         }
1294
1295         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1296                  tev->point.offset);
1297
1298         /* Expand special probe argument if exist */
1299         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1300         if (args == NULL) {
1301                 ret = -ENOMEM;
1302                 goto end;
1303         }
1304
1305         ret = expand_probe_args(sc_die, pf, args);
1306         if (ret < 0)
1307                 goto end;
1308
1309         tev->nargs = ret;
1310         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1311         if (tev->args == NULL) {
1312                 ret = -ENOMEM;
1313                 goto end;
1314         }
1315
1316         /* Find each argument */
1317         for (i = 0; i < tev->nargs; i++) {
1318                 pf->pvar = &args[i];
1319                 pf->tvar = &tev->args[i];
1320                 /* Variable should be found from scope DIE */
1321                 ret = find_variable(sc_die, pf);
1322                 if (ret != 0)
1323                         break;
1324         }
1325
1326 end:
1327         if (ret) {
1328                 clear_probe_trace_event(tev);
1329                 tf->ntevs--;
1330         }
1331         free(args);
1332         return ret;
1333 }
1334
1335 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1336 int debuginfo__find_trace_events(struct debuginfo *dbg,
1337                                  struct perf_probe_event *pev,
1338                                  struct probe_trace_event **tevs)
1339 {
1340         struct trace_event_finder tf = {
1341                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1342                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1343         int ret, i;
1344
1345         /* Allocate result tevs array */
1346         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1347         if (*tevs == NULL)
1348                 return -ENOMEM;
1349
1350         tf.tevs = *tevs;
1351         tf.ntevs = 0;
1352
1353         ret = debuginfo__find_probes(dbg, &tf.pf);
1354         if (ret < 0 || tf.ntevs == 0) {
1355                 for (i = 0; i < tf.ntevs; i++)
1356                         clear_probe_trace_event(&tf.tevs[i]);
1357                 zfree(tevs);
1358                 return ret;
1359         }
1360
1361         return (ret < 0) ? ret : tf.ntevs;
1362 }
1363
1364 /* Collect available variables in this scope */
1365 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1366 {
1367         struct available_var_finder *af = data;
1368         struct variable_list *vl;
1369         struct strbuf buf = STRBUF_INIT;
1370         int tag, ret;
1371
1372         vl = &af->vls[af->nvls - 1];
1373
1374         tag = dwarf_tag(die_mem);
1375         if (tag == DW_TAG_formal_parameter ||
1376             tag == DW_TAG_variable) {
1377                 ret = convert_variable_location(die_mem, af->pf.addr,
1378                                                 af->pf.fb_ops, &af->pf.sp_die,
1379                                                 af->pf.machine, NULL);
1380                 if (ret == 0 || ret == -ERANGE) {
1381                         int ret2;
1382                         bool externs = !af->child;
1383
1384                         if (strbuf_init(&buf, 64) < 0)
1385                                 goto error;
1386
1387                         if (probe_conf.show_location_range) {
1388                                 if (!externs)
1389                                         ret2 = strbuf_add(&buf,
1390                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1391                                 else
1392                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1393                                 if (ret2)
1394                                         goto error;
1395                         }
1396
1397                         ret2 = die_get_varname(die_mem, &buf);
1398
1399                         if (!ret2 && probe_conf.show_location_range &&
1400                                 !externs) {
1401                                 if (strbuf_addch(&buf, '\t') < 0)
1402                                         goto error;
1403                                 ret2 = die_get_var_range(&af->pf.sp_die,
1404                                                         die_mem, &buf);
1405                         }
1406
1407                         pr_debug("Add new var: %s\n", buf.buf);
1408                         if (ret2 == 0) {
1409                                 strlist__add(vl->vars,
1410                                         strbuf_detach(&buf, NULL));
1411                         }
1412                         strbuf_release(&buf);
1413                 }
1414         }
1415
1416         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1417                 return DIE_FIND_CB_CONTINUE;
1418         else
1419                 return DIE_FIND_CB_SIBLING;
1420 error:
1421         strbuf_release(&buf);
1422         pr_debug("Error in strbuf\n");
1423         return DIE_FIND_CB_END;
1424 }
1425
1426 static bool available_var_finder_overlap(struct available_var_finder *af)
1427 {
1428         int i;
1429
1430         for (i = 0; i < af->nvls; i++) {
1431                 if (af->pf.addr == af->vls[i].point.address)
1432                         return true;
1433         }
1434         return false;
1435
1436 }
1437
1438 /* Add a found vars into available variables list */
1439 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1440 {
1441         struct available_var_finder *af =
1442                         container_of(pf, struct available_var_finder, pf);
1443         struct perf_probe_point *pp = &pf->pev->point;
1444         struct variable_list *vl;
1445         Dwarf_Die die_mem;
1446         int ret;
1447
1448         /*
1449          * For some reason (e.g. different column assigned to same address),
1450          * this callback can be called with the address which already passed.
1451          * Ignore it first.
1452          */
1453         if (available_var_finder_overlap(af))
1454                 return 0;
1455
1456         /* Check number of tevs */
1457         if (af->nvls == af->max_vls) {
1458                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1459                 return -ERANGE;
1460         }
1461         vl = &af->vls[af->nvls++];
1462
1463         /* Trace point should be converted from subprogram DIE */
1464         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1465                                      pp->retprobe, pp->function, &vl->point);
1466         if (ret < 0)
1467                 return ret;
1468
1469         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1470                  vl->point.offset);
1471
1472         /* Find local variables */
1473         vl->vars = strlist__new(NULL, NULL);
1474         if (vl->vars == NULL)
1475                 return -ENOMEM;
1476         af->child = true;
1477         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1478
1479         /* Find external variables */
1480         if (!probe_conf.show_ext_vars)
1481                 goto out;
1482         /* Don't need to search child DIE for external vars. */
1483         af->child = false;
1484         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1485
1486 out:
1487         if (strlist__empty(vl->vars)) {
1488                 strlist__delete(vl->vars);
1489                 vl->vars = NULL;
1490         }
1491
1492         return ret;
1493 }
1494
1495 /*
1496  * Find available variables at given probe point
1497  * Return the number of found probe points. Return 0 if there is no
1498  * matched probe point. Return <0 if an error occurs.
1499  */
1500 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1501                                       struct perf_probe_event *pev,
1502                                       struct variable_list **vls)
1503 {
1504         struct available_var_finder af = {
1505                         .pf = {.pev = pev, .callback = add_available_vars},
1506                         .mod = dbg->mod,
1507                         .max_vls = probe_conf.max_probes};
1508         int ret;
1509
1510         /* Allocate result vls array */
1511         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1512         if (*vls == NULL)
1513                 return -ENOMEM;
1514
1515         af.vls = *vls;
1516         af.nvls = 0;
1517
1518         ret = debuginfo__find_probes(dbg, &af.pf);
1519         if (ret < 0) {
1520                 /* Free vlist for error */
1521                 while (af.nvls--) {
1522                         zfree(&af.vls[af.nvls].point.symbol);
1523                         strlist__delete(af.vls[af.nvls].vars);
1524                 }
1525                 zfree(vls);
1526                 return ret;
1527         }
1528
1529         return (ret < 0) ? ret : af.nvls;
1530 }
1531
1532 /* For the kernel module, we need a special code to get a DIE */
1533 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1534                                 bool adjust_offset)
1535 {
1536         int n, i;
1537         Elf32_Word shndx;
1538         Elf_Scn *scn;
1539         Elf *elf;
1540         GElf_Shdr mem, *shdr;
1541         const char *p;
1542
1543         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1544         if (!elf)
1545                 return -EINVAL;
1546
1547         /* Get the number of relocations */
1548         n = dwfl_module_relocations(dbg->mod);
1549         if (n < 0)
1550                 return -ENOENT;
1551         /* Search the relocation related .text section */
1552         for (i = 0; i < n; i++) {
1553                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1554                 if (strcmp(p, ".text") == 0) {
1555                         /* OK, get the section header */
1556                         scn = elf_getscn(elf, shndx);
1557                         if (!scn)
1558                                 return -ENOENT;
1559                         shdr = gelf_getshdr(scn, &mem);
1560                         if (!shdr)
1561                                 return -ENOENT;
1562                         *offs = shdr->sh_addr;
1563                         if (adjust_offset)
1564                                 *offs -= shdr->sh_offset;
1565                 }
1566         }
1567         return 0;
1568 }
1569
1570 /* Reverse search */
1571 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1572                                 struct perf_probe_point *ppt)
1573 {
1574         Dwarf_Die cudie, spdie, indie;
1575         Dwarf_Addr _addr = 0, baseaddr = 0;
1576         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1577         int baseline = 0, lineno = 0, ret = 0;
1578
1579         /* We always need to relocate the address for aranges */
1580         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1581                 addr += baseaddr;
1582         /* Find cu die */
1583         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1584                 pr_warning("Failed to find debug information for address %lx\n",
1585                            addr);
1586                 ret = -EINVAL;
1587                 goto end;
1588         }
1589
1590         /* Find a corresponding line (filename and lineno) */
1591         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1592         /* Don't care whether it failed or not */
1593
1594         /* Find a corresponding function (name, baseline and baseaddr) */
1595         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1596                 /* Get function entry information */
1597                 func = basefunc = dwarf_diename(&spdie);
1598                 if (!func ||
1599                     die_entrypc(&spdie, &baseaddr) != 0 ||
1600                     dwarf_decl_line(&spdie, &baseline) != 0) {
1601                         lineno = 0;
1602                         goto post;
1603                 }
1604
1605                 fname = dwarf_decl_file(&spdie);
1606                 if (addr == (unsigned long)baseaddr) {
1607                         /* Function entry - Relative line number is 0 */
1608                         lineno = baseline;
1609                         goto post;
1610                 }
1611
1612                 /* Track down the inline functions step by step */
1613                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1614                                                 &indie)) {
1615                         /* There is an inline function */
1616                         if (die_entrypc(&indie, &_addr) == 0 &&
1617                             _addr == addr) {
1618                                 /*
1619                                  * addr is at an inline function entry.
1620                                  * In this case, lineno should be the call-site
1621                                  * line number. (overwrite lineinfo)
1622                                  */
1623                                 lineno = die_get_call_lineno(&indie);
1624                                 fname = die_get_call_file(&indie);
1625                                 break;
1626                         } else {
1627                                 /*
1628                                  * addr is in an inline function body.
1629                                  * Since lineno points one of the lines
1630                                  * of the inline function, baseline should
1631                                  * be the entry line of the inline function.
1632                                  */
1633                                 tmp = dwarf_diename(&indie);
1634                                 if (!tmp ||
1635                                     dwarf_decl_line(&indie, &baseline) != 0)
1636                                         break;
1637                                 func = tmp;
1638                                 spdie = indie;
1639                         }
1640                 }
1641                 /* Verify the lineno and baseline are in a same file */
1642                 tmp = dwarf_decl_file(&spdie);
1643                 if (!tmp || strcmp(tmp, fname) != 0)
1644                         lineno = 0;
1645         }
1646
1647 post:
1648         /* Make a relative line number or an offset */
1649         if (lineno)
1650                 ppt->line = lineno - baseline;
1651         else if (basefunc) {
1652                 ppt->offset = addr - (unsigned long)baseaddr;
1653                 func = basefunc;
1654         }
1655
1656         /* Duplicate strings */
1657         if (func) {
1658                 ppt->function = strdup(func);
1659                 if (ppt->function == NULL) {
1660                         ret = -ENOMEM;
1661                         goto end;
1662                 }
1663         }
1664         if (fname) {
1665                 ppt->file = strdup(fname);
1666                 if (ppt->file == NULL) {
1667                         zfree(&ppt->function);
1668                         ret = -ENOMEM;
1669                         goto end;
1670                 }
1671         }
1672 end:
1673         if (ret == 0 && (fname || func))
1674                 ret = 1;        /* Found a point */
1675         return ret;
1676 }
1677
1678 /* Add a line and store the src path */
1679 static int line_range_add_line(const char *src, unsigned int lineno,
1680                                struct line_range *lr)
1681 {
1682         /* Copy source path */
1683         if (!lr->path) {
1684                 lr->path = strdup(src);
1685                 if (lr->path == NULL)
1686                         return -ENOMEM;
1687         }
1688         return intlist__add(lr->line_list, lineno);
1689 }
1690
1691 static int line_range_walk_cb(const char *fname, int lineno,
1692                               Dwarf_Addr addr __maybe_unused,
1693                               void *data)
1694 {
1695         struct line_finder *lf = data;
1696         int err;
1697
1698         if ((strtailcmp(fname, lf->fname) != 0) ||
1699             (lf->lno_s > lineno || lf->lno_e < lineno))
1700                 return 0;
1701
1702         err = line_range_add_line(fname, lineno, lf->lr);
1703         if (err < 0 && err != -EEXIST)
1704                 return err;
1705
1706         return 0;
1707 }
1708
1709 /* Find line range from its line number */
1710 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1711 {
1712         int ret;
1713
1714         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1715
1716         /* Update status */
1717         if (ret >= 0)
1718                 if (!intlist__empty(lf->lr->line_list))
1719                         ret = lf->found = 1;
1720                 else
1721                         ret = 0;        /* Lines are not found */
1722         else {
1723                 zfree(&lf->lr->path);
1724         }
1725         return ret;
1726 }
1727
1728 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1729 {
1730         int ret = find_line_range_by_line(in_die, data);
1731
1732         /*
1733          * We have to check all instances of inlined function, because
1734          * some execution paths can be optimized out depends on the
1735          * function argument of instances. However, if an error occurs,
1736          * it should be handled by the caller.
1737          */
1738         return ret < 0 ? ret : 0;
1739 }
1740
1741 /* Search function definition from function name */
1742 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1743 {
1744         struct dwarf_callback_param *param = data;
1745         struct line_finder *lf = param->data;
1746         struct line_range *lr = lf->lr;
1747
1748         /* Check declared file */
1749         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1750                 return DWARF_CB_OK;
1751
1752         if (die_is_func_def(sp_die) &&
1753             die_match_name(sp_die, lr->function)) {
1754                 lf->fname = dwarf_decl_file(sp_die);
1755                 dwarf_decl_line(sp_die, &lr->offset);
1756                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1757                 lf->lno_s = lr->offset + lr->start;
1758                 if (lf->lno_s < 0)      /* Overflow */
1759                         lf->lno_s = INT_MAX;
1760                 lf->lno_e = lr->offset + lr->end;
1761                 if (lf->lno_e < 0)      /* Overflow */
1762                         lf->lno_e = INT_MAX;
1763                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1764                 lr->start = lf->lno_s;
1765                 lr->end = lf->lno_e;
1766                 if (!die_is_func_instance(sp_die))
1767                         param->retval = die_walk_instances(sp_die,
1768                                                 line_range_inline_cb, lf);
1769                 else
1770                         param->retval = find_line_range_by_line(sp_die, lf);
1771                 return DWARF_CB_ABORT;
1772         }
1773         return DWARF_CB_OK;
1774 }
1775
1776 static int find_line_range_by_func(struct line_finder *lf)
1777 {
1778         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1779         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1780         return param.retval;
1781 }
1782
1783 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1784 {
1785         struct line_finder lf = {.lr = lr, .found = 0};
1786         int ret = 0;
1787         Dwarf_Off off = 0, noff;
1788         size_t cuhl;
1789         Dwarf_Die *diep;
1790         const char *comp_dir;
1791
1792         /* Fastpath: lookup by function name from .debug_pubnames section */
1793         if (lr->function) {
1794                 struct pubname_callback_param pubname_param = {
1795                         .function = lr->function, .file = lr->file,
1796                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1797                 struct dwarf_callback_param line_range_param = {
1798                         .data = (void *)&lf, .retval = 0};
1799
1800                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1801                                   &pubname_param, 0);
1802                 if (pubname_param.found) {
1803                         line_range_search_cb(&lf.sp_die, &line_range_param);
1804                         if (lf.found)
1805                                 goto found;
1806                 }
1807         }
1808
1809         /* Loop on CUs (Compilation Unit) */
1810         while (!lf.found && ret >= 0) {
1811                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1812                                  NULL, NULL, NULL) != 0)
1813                         break;
1814
1815                 /* Get the DIE(Debugging Information Entry) of this CU */
1816                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1817                 if (!diep)
1818                         continue;
1819
1820                 /* Check if target file is included. */
1821                 if (lr->file)
1822                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1823                 else
1824                         lf.fname = 0;
1825
1826                 if (!lr->file || lf.fname) {
1827                         if (lr->function)
1828                                 ret = find_line_range_by_func(&lf);
1829                         else {
1830                                 lf.lno_s = lr->start;
1831                                 lf.lno_e = lr->end;
1832                                 ret = find_line_range_by_line(NULL, &lf);
1833                         }
1834                 }
1835                 off = noff;
1836         }
1837
1838 found:
1839         /* Store comp_dir */
1840         if (lf.found) {
1841                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1842                 if (comp_dir) {
1843                         lr->comp_dir = strdup(comp_dir);
1844                         if (!lr->comp_dir)
1845                                 ret = -ENOMEM;
1846                 }
1847         }
1848
1849         pr_debug("path: %s\n", lr->path);
1850         return (ret < 0) ? ret : lf.found;
1851 }
1852
1853 /*
1854  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1855  * and chop off leading directories that do not exist. Result is passed back as
1856  * a newly allocated path on success.
1857  * Return 0 if file was found and readable, -errno otherwise.
1858  */
1859 int get_real_path(const char *raw_path, const char *comp_dir,
1860                          char **new_path)
1861 {
1862         const char *prefix = symbol_conf.source_prefix;
1863
1864         if (!prefix) {
1865                 if (raw_path[0] != '/' && comp_dir)
1866                         /* If not an absolute path, try to use comp_dir */
1867                         prefix = comp_dir;
1868                 else {
1869                         if (access(raw_path, R_OK) == 0) {
1870                                 *new_path = strdup(raw_path);
1871                                 return *new_path ? 0 : -ENOMEM;
1872                         } else
1873                                 return -errno;
1874                 }
1875         }
1876
1877         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1878         if (!*new_path)
1879                 return -ENOMEM;
1880
1881         for (;;) {
1882                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1883
1884                 if (access(*new_path, R_OK) == 0)
1885                         return 0;
1886
1887                 if (!symbol_conf.source_prefix) {
1888                         /* In case of searching comp_dir, don't retry */
1889                         zfree(new_path);
1890                         return -errno;
1891                 }
1892
1893                 switch (errno) {
1894                 case ENAMETOOLONG:
1895                 case ENOENT:
1896                 case EROFS:
1897                 case EFAULT:
1898                         raw_path = strchr(++raw_path, '/');
1899                         if (!raw_path) {
1900                                 zfree(new_path);
1901                                 return -ENOENT;
1902                         }
1903                         continue;
1904
1905                 default:
1906                         zfree(new_path);
1907                         return -errno;
1908                 }
1909         }
1910 }