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Linux/tools/perf/util/probe-finder.c

Version: ~ [ linux-5.12 ] ~ [ linux-5.11.16 ] ~ [ linux-5.10.32 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.114 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.188 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.231 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.267 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.267 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  * probe-finder.c : C expression to kprobe event converter
  3  *
  4  * Written by Masami Hiramatsu <mhiramat@redhat.com>
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License as published by
  8  * the Free Software Foundation; either version 2 of the License, or
  9  * (at your option) any later version.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public License
 17  * along with this program; if not, write to the Free Software
 18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 19  *
 20  */
 21 
 22 #include <sys/utsname.h>
 23 #include <sys/types.h>
 24 #include <sys/stat.h>
 25 #include <fcntl.h>
 26 #include <errno.h>
 27 #include <stdio.h>
 28 #include <unistd.h>
 29 #include <stdlib.h>
 30 #include <string.h>
 31 #include <stdarg.h>
 32 #include <dwarf-regs.h>
 33 
 34 #include <linux/bitops.h>
 35 #include "event.h"
 36 #include "dso.h"
 37 #include "debug.h"
 38 #include "intlist.h"
 39 #include "util.h"
 40 #include "symbol.h"
 41 #include "probe-finder.h"
 42 
 43 /* Kprobe tracer basic type is up to u64 */
 44 #define MAX_BASIC_TYPE_BITS     64
 45 
 46 /* Dwarf FL wrappers */
 47 static char *debuginfo_path;    /* Currently dummy */
 48 
 49 static const Dwfl_Callbacks offline_callbacks = {
 50         .find_debuginfo = dwfl_standard_find_debuginfo,
 51         .debuginfo_path = &debuginfo_path,
 52 
 53         .section_address = dwfl_offline_section_address,
 54 
 55         /* We use this table for core files too.  */
 56         .find_elf = dwfl_build_id_find_elf,
 57 };
 58 
 59 /* Get a Dwarf from offline image */
 60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
 61                                          const char *path)
 62 {
 63         int fd;
 64 
 65         fd = open(path, O_RDONLY);
 66         if (fd < 0)
 67                 return fd;
 68 
 69         dbg->dwfl = dwfl_begin(&offline_callbacks);
 70         if (!dbg->dwfl)
 71                 goto error;
 72 
 73         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
 74         if (!dbg->mod)
 75                 goto error;
 76 
 77         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
 78         if (!dbg->dbg)
 79                 goto error;
 80 
 81         return 0;
 82 error:
 83         if (dbg->dwfl)
 84                 dwfl_end(dbg->dwfl);
 85         else
 86                 close(fd);
 87         memset(dbg, 0, sizeof(*dbg));
 88 
 89         return -ENOENT;
 90 }
 91 
 92 static struct debuginfo *__debuginfo__new(const char *path)
 93 {
 94         struct debuginfo *dbg = zalloc(sizeof(*dbg));
 95         if (!dbg)
 96                 return NULL;
 97 
 98         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 99                 zfree(&dbg);
100         if (dbg)
101                 pr_debug("Open Debuginfo file: %s\n", path);
102         return dbg;
103 }
104 
105 enum dso_binary_type distro_dwarf_types[] = {
106         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
107         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
108         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
109         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
110         DSO_BINARY_TYPE__NOT_FOUND,
111 };
112 
113 struct debuginfo *debuginfo__new(const char *path)
114 {
115         enum dso_binary_type *type;
116         char buf[PATH_MAX], nil = '\0';
117         struct dso *dso;
118         struct debuginfo *dinfo = NULL;
119 
120         /* Try to open distro debuginfo files */
121         dso = dso__new(path);
122         if (!dso)
123                 goto out;
124 
125         for (type = distro_dwarf_types;
126              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
127              type++) {
128                 if (dso__read_binary_type_filename(dso, *type, &nil,
129                                                    buf, PATH_MAX) < 0)
130                         continue;
131                 dinfo = __debuginfo__new(buf);
132         }
133         dso__put(dso);
134 
135 out:
136         /* if failed to open all distro debuginfo, open given binary */
137         return dinfo ? : __debuginfo__new(path);
138 }
139 
140 void debuginfo__delete(struct debuginfo *dbg)
141 {
142         if (dbg) {
143                 if (dbg->dwfl)
144                         dwfl_end(dbg->dwfl);
145                 free(dbg);
146         }
147 }
148 
149 /*
150  * Probe finder related functions
151  */
152 
153 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
154 {
155         struct probe_trace_arg_ref *ref;
156         ref = zalloc(sizeof(struct probe_trace_arg_ref));
157         if (ref != NULL)
158                 ref->offset = offs;
159         return ref;
160 }
161 
162 /*
163  * Convert a location into trace_arg.
164  * If tvar == NULL, this just checks variable can be converted.
165  * If fentry == true and vr_die is a parameter, do huristic search
166  * for the location fuzzed by function entry mcount.
167  */
168 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
169                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
170                                      struct probe_trace_arg *tvar)
171 {
172         Dwarf_Attribute attr;
173         Dwarf_Addr tmp = 0;
174         Dwarf_Op *op;
175         size_t nops;
176         unsigned int regn;
177         Dwarf_Word offs = 0;
178         bool ref = false;
179         const char *regs;
180         int ret, ret2 = 0;
181 
182         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
183                 goto static_var;
184 
185         /* TODO: handle more than 1 exprs */
186         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
187                 return -EINVAL; /* Broken DIE ? */
188         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
189                 ret = dwarf_entrypc(sp_die, &tmp);
190                 if (ret)
191                         return -ENOENT;
192 
193                 if (probe_conf.show_location_range &&
194                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
195                         ret2 = -ERANGE;
196                 } else if (addr != tmp ||
197                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
198                         return -ENOENT;
199                 }
200 
201                 ret = dwarf_highpc(sp_die, &tmp);
202                 if (ret)
203                         return -ENOENT;
204                 /*
205                  * This is fuzzed by fentry mcount. We try to find the
206                  * parameter location at the earliest address.
207                  */
208                 for (addr += 1; addr <= tmp; addr++) {
209                         if (dwarf_getlocation_addr(&attr, addr, &op,
210                                                    &nops, 1) > 0)
211                                 goto found;
212                 }
213                 return -ENOENT;
214         }
215 found:
216         if (nops == 0)
217                 /* TODO: Support const_value */
218                 return -ENOENT;
219 
220         if (op->atom == DW_OP_addr) {
221 static_var:
222                 if (!tvar)
223                         return ret2;
224                 /* Static variables on memory (not stack), make @varname */
225                 ret = strlen(dwarf_diename(vr_die));
226                 tvar->value = zalloc(ret + 2);
227                 if (tvar->value == NULL)
228                         return -ENOMEM;
229                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
230                 tvar->ref = alloc_trace_arg_ref((long)offs);
231                 if (tvar->ref == NULL)
232                         return -ENOMEM;
233                 return ret2;
234         }
235 
236         /* If this is based on frame buffer, set the offset */
237         if (op->atom == DW_OP_fbreg) {
238                 if (fb_ops == NULL)
239                         return -ENOTSUP;
240                 ref = true;
241                 offs = op->number;
242                 op = &fb_ops[0];
243         }
244 
245         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
246                 regn = op->atom - DW_OP_breg0;
247                 offs += op->number;
248                 ref = true;
249         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
250                 regn = op->atom - DW_OP_reg0;
251         } else if (op->atom == DW_OP_bregx) {
252                 regn = op->number;
253                 offs += op->number2;
254                 ref = true;
255         } else if (op->atom == DW_OP_regx) {
256                 regn = op->number;
257         } else {
258                 pr_debug("DW_OP %x is not supported.\n", op->atom);
259                 return -ENOTSUP;
260         }
261 
262         if (!tvar)
263                 return ret2;
264 
265         regs = get_arch_regstr(regn);
266         if (!regs) {
267                 /* This should be a bug in DWARF or this tool */
268                 pr_warning("Mapping for the register number %u "
269                            "missing on this architecture.\n", regn);
270                 return -ENOTSUP;
271         }
272 
273         tvar->value = strdup(regs);
274         if (tvar->value == NULL)
275                 return -ENOMEM;
276 
277         if (ref) {
278                 tvar->ref = alloc_trace_arg_ref((long)offs);
279                 if (tvar->ref == NULL)
280                         return -ENOMEM;
281         }
282         return ret2;
283 }
284 
285 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
286 
287 static int convert_variable_type(Dwarf_Die *vr_die,
288                                  struct probe_trace_arg *tvar,
289                                  const char *cast)
290 {
291         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
292         Dwarf_Die type;
293         char buf[16];
294         char sbuf[STRERR_BUFSIZE];
295         int bsize, boffs, total;
296         int ret;
297 
298         /* TODO: check all types */
299         if (cast && strcmp(cast, "string") != 0) {
300                 /* Non string type is OK */
301                 tvar->type = strdup(cast);
302                 return (tvar->type == NULL) ? -ENOMEM : 0;
303         }
304 
305         bsize = dwarf_bitsize(vr_die);
306         if (bsize > 0) {
307                 /* This is a bitfield */
308                 boffs = dwarf_bitoffset(vr_die);
309                 total = dwarf_bytesize(vr_die);
310                 if (boffs < 0 || total < 0)
311                         return -ENOENT;
312                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
313                                 BYTES_TO_BITS(total));
314                 goto formatted;
315         }
316 
317         if (die_get_real_type(vr_die, &type) == NULL) {
318                 pr_warning("Failed to get a type information of %s.\n",
319                            dwarf_diename(vr_die));
320                 return -ENOENT;
321         }
322 
323         pr_debug("%s type is %s.\n",
324                  dwarf_diename(vr_die), dwarf_diename(&type));
325 
326         if (cast && strcmp(cast, "string") == 0) {      /* String type */
327                 ret = dwarf_tag(&type);
328                 if (ret != DW_TAG_pointer_type &&
329                     ret != DW_TAG_array_type) {
330                         pr_warning("Failed to cast into string: "
331                                    "%s(%s) is not a pointer nor array.\n",
332                                    dwarf_diename(vr_die), dwarf_diename(&type));
333                         return -EINVAL;
334                 }
335                 if (die_get_real_type(&type, &type) == NULL) {
336                         pr_warning("Failed to get a type"
337                                    " information.\n");
338                         return -ENOENT;
339                 }
340                 if (ret == DW_TAG_pointer_type) {
341                         while (*ref_ptr)
342                                 ref_ptr = &(*ref_ptr)->next;
343                         /* Add new reference with offset +0 */
344                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
345                         if (*ref_ptr == NULL) {
346                                 pr_warning("Out of memory error\n");
347                                 return -ENOMEM;
348                         }
349                 }
350                 if (!die_compare_name(&type, "char") &&
351                     !die_compare_name(&type, "unsigned char")) {
352                         pr_warning("Failed to cast into string: "
353                                    "%s is not (unsigned) char *.\n",
354                                    dwarf_diename(vr_die));
355                         return -EINVAL;
356                 }
357                 tvar->type = strdup(cast);
358                 return (tvar->type == NULL) ? -ENOMEM : 0;
359         }
360 
361         ret = dwarf_bytesize(&type);
362         if (ret <= 0)
363                 /* No size ... try to use default type */
364                 return 0;
365         ret = BYTES_TO_BITS(ret);
366 
367         /* Check the bitwidth */
368         if (ret > MAX_BASIC_TYPE_BITS) {
369                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
370                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
371                 ret = MAX_BASIC_TYPE_BITS;
372         }
373         ret = snprintf(buf, 16, "%c%d",
374                        die_is_signed_type(&type) ? 's' : 'u', ret);
375 
376 formatted:
377         if (ret < 0 || ret >= 16) {
378                 if (ret >= 16)
379                         ret = -E2BIG;
380                 pr_warning("Failed to convert variable type: %s\n",
381                            strerror_r(-ret, sbuf, sizeof(sbuf)));
382                 return ret;
383         }
384         tvar->type = strdup(buf);
385         if (tvar->type == NULL)
386                 return -ENOMEM;
387         return 0;
388 }
389 
390 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
391                                     struct perf_probe_arg_field *field,
392                                     struct probe_trace_arg_ref **ref_ptr,
393                                     Dwarf_Die *die_mem)
394 {
395         struct probe_trace_arg_ref *ref = *ref_ptr;
396         Dwarf_Die type;
397         Dwarf_Word offs;
398         int ret, tag;
399 
400         pr_debug("converting %s in %s\n", field->name, varname);
401         if (die_get_real_type(vr_die, &type) == NULL) {
402                 pr_warning("Failed to get the type of %s.\n", varname);
403                 return -ENOENT;
404         }
405         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
406         tag = dwarf_tag(&type);
407 
408         if (field->name[0] == '[' &&
409             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
410                 if (field->next)
411                         /* Save original type for next field */
412                         memcpy(die_mem, &type, sizeof(*die_mem));
413                 /* Get the type of this array */
414                 if (die_get_real_type(&type, &type) == NULL) {
415                         pr_warning("Failed to get the type of %s.\n", varname);
416                         return -ENOENT;
417                 }
418                 pr_debug2("Array real type: (%x)\n",
419                          (unsigned)dwarf_dieoffset(&type));
420                 if (tag == DW_TAG_pointer_type) {
421                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
422                         if (ref == NULL)
423                                 return -ENOMEM;
424                         if (*ref_ptr)
425                                 (*ref_ptr)->next = ref;
426                         else
427                                 *ref_ptr = ref;
428                 }
429                 ref->offset += dwarf_bytesize(&type) * field->index;
430                 if (!field->next)
431                         /* Save vr_die for converting types */
432                         memcpy(die_mem, vr_die, sizeof(*die_mem));
433                 goto next;
434         } else if (tag == DW_TAG_pointer_type) {
435                 /* Check the pointer and dereference */
436                 if (!field->ref) {
437                         pr_err("Semantic error: %s must be referred by '->'\n",
438                                field->name);
439                         return -EINVAL;
440                 }
441                 /* Get the type pointed by this pointer */
442                 if (die_get_real_type(&type, &type) == NULL) {
443                         pr_warning("Failed to get the type of %s.\n", varname);
444                         return -ENOENT;
445                 }
446                 /* Verify it is a data structure  */
447                 tag = dwarf_tag(&type);
448                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
449                         pr_warning("%s is not a data structure nor an union.\n",
450                                    varname);
451                         return -EINVAL;
452                 }
453 
454                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
455                 if (ref == NULL)
456                         return -ENOMEM;
457                 if (*ref_ptr)
458                         (*ref_ptr)->next = ref;
459                 else
460                         *ref_ptr = ref;
461         } else {
462                 /* Verify it is a data structure  */
463                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
464                         pr_warning("%s is not a data structure nor an union.\n",
465                                    varname);
466                         return -EINVAL;
467                 }
468                 if (field->name[0] == '[') {
469                         pr_err("Semantic error: %s is not a pointer"
470                                " nor array.\n", varname);
471                         return -EINVAL;
472                 }
473                 /* While prcessing unnamed field, we don't care about this */
474                 if (field->ref && dwarf_diename(vr_die)) {
475                         pr_err("Semantic error: %s must be referred by '.'\n",
476                                field->name);
477                         return -EINVAL;
478                 }
479                 if (!ref) {
480                         pr_warning("Structure on a register is not "
481                                    "supported yet.\n");
482                         return -ENOTSUP;
483                 }
484         }
485 
486         if (die_find_member(&type, field->name, die_mem) == NULL) {
487                 pr_warning("%s(type:%s) has no member %s.\n", varname,
488                            dwarf_diename(&type), field->name);
489                 return -EINVAL;
490         }
491 
492         /* Get the offset of the field */
493         if (tag == DW_TAG_union_type) {
494                 offs = 0;
495         } else {
496                 ret = die_get_data_member_location(die_mem, &offs);
497                 if (ret < 0) {
498                         pr_warning("Failed to get the offset of %s.\n",
499                                    field->name);
500                         return ret;
501                 }
502         }
503         ref->offset += (long)offs;
504 
505         /* If this member is unnamed, we need to reuse this field */
506         if (!dwarf_diename(die_mem))
507                 return convert_variable_fields(die_mem, varname, field,
508                                                 &ref, die_mem);
509 
510 next:
511         /* Converting next field */
512         if (field->next)
513                 return convert_variable_fields(die_mem, field->name,
514                                         field->next, &ref, die_mem);
515         else
516                 return 0;
517 }
518 
519 /* Show a variables in kprobe event format */
520 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
521 {
522         Dwarf_Die die_mem;
523         int ret;
524 
525         pr_debug("Converting variable %s into trace event.\n",
526                  dwarf_diename(vr_die));
527 
528         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
529                                         &pf->sp_die, pf->tvar);
530         if (ret == -ENOENT || ret == -EINVAL) {
531                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
532                        " Perhaps it has been optimized out.\n"
533                        " Use -V with the --range option to show '%s' location range.\n",
534                        pf->pvar->var, pf->pvar->var);
535         } else if (ret == -ENOTSUP)
536                 pr_err("Sorry, we don't support this variable location yet.\n");
537         else if (ret == 0 && pf->pvar->field) {
538                 ret = convert_variable_fields(vr_die, pf->pvar->var,
539                                               pf->pvar->field, &pf->tvar->ref,
540                                               &die_mem);
541                 vr_die = &die_mem;
542         }
543         if (ret == 0)
544                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
545         /* *expr will be cached in libdw. Don't free it. */
546         return ret;
547 }
548 
549 /* Find a variable in a scope DIE */
550 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
551 {
552         Dwarf_Die vr_die;
553         char buf[32], *ptr;
554         int ret = 0;
555 
556         if (!is_c_varname(pf->pvar->var)) {
557                 /* Copy raw parameters */
558                 pf->tvar->value = strdup(pf->pvar->var);
559                 if (pf->tvar->value == NULL)
560                         return -ENOMEM;
561                 if (pf->pvar->type) {
562                         pf->tvar->type = strdup(pf->pvar->type);
563                         if (pf->tvar->type == NULL)
564                                 return -ENOMEM;
565                 }
566                 if (pf->pvar->name) {
567                         pf->tvar->name = strdup(pf->pvar->name);
568                         if (pf->tvar->name == NULL)
569                                 return -ENOMEM;
570                 } else
571                         pf->tvar->name = NULL;
572                 return 0;
573         }
574 
575         if (pf->pvar->name)
576                 pf->tvar->name = strdup(pf->pvar->name);
577         else {
578                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
579                 if (ret < 0)
580                         return ret;
581                 ptr = strchr(buf, ':'); /* Change type separator to _ */
582                 if (ptr)
583                         *ptr = '_';
584                 pf->tvar->name = strdup(buf);
585         }
586         if (pf->tvar->name == NULL)
587                 return -ENOMEM;
588 
589         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
590         /* Search child die for local variables and parameters. */
591         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
592                 /* Search again in global variables */
593                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
594                                                 0, &vr_die)) {
595                         pr_warning("Failed to find '%s' in this function.\n",
596                                    pf->pvar->var);
597                         ret = -ENOENT;
598                 }
599         }
600         if (ret >= 0)
601                 ret = convert_variable(&vr_die, pf);
602 
603         return ret;
604 }
605 
606 /* Convert subprogram DIE to trace point */
607 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
608                                   Dwarf_Addr paddr, bool retprobe,
609                                   struct probe_trace_point *tp)
610 {
611         Dwarf_Addr eaddr, highaddr;
612         GElf_Sym sym;
613         const char *symbol;
614 
615         /* Verify the address is correct */
616         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
617                 pr_warning("Failed to get entry address of %s\n",
618                            dwarf_diename(sp_die));
619                 return -ENOENT;
620         }
621         if (dwarf_highpc(sp_die, &highaddr) != 0) {
622                 pr_warning("Failed to get end address of %s\n",
623                            dwarf_diename(sp_die));
624                 return -ENOENT;
625         }
626         if (paddr > highaddr) {
627                 pr_warning("Offset specified is greater than size of %s\n",
628                            dwarf_diename(sp_die));
629                 return -EINVAL;
630         }
631 
632         symbol = dwarf_diename(sp_die);
633         if (!symbol) {
634                 /* Try to get the symbol name from symtab */
635                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
636                 if (!symbol) {
637                         pr_warning("Failed to find symbol at 0x%lx\n",
638                                    (unsigned long)paddr);
639                         return -ENOENT;
640                 }
641                 eaddr = sym.st_value;
642         }
643         tp->offset = (unsigned long)(paddr - eaddr);
644         tp->address = (unsigned long)paddr;
645         tp->symbol = strdup(symbol);
646         if (!tp->symbol)
647                 return -ENOMEM;
648 
649         /* Return probe must be on the head of a subprogram */
650         if (retprobe) {
651                 if (eaddr != paddr) {
652                         pr_warning("Return probe must be on the head of"
653                                    " a real function.\n");
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         size_t nops;
667         int ret;
668 
669         if (!sc_die) {
670                 pr_err("Caller must pass a scope DIE. Program error.\n");
671                 return -EINVAL;
672         }
673 
674         /* If not a real subprogram, find a real one */
675         if (!die_is_func_def(sc_die)) {
676                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
677                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
678                                 pr_warning("Ignoring tail call from %s\n",
679                                                 dwarf_diename(&pf->sp_die));
680                                 return 0;
681                         } else {
682                                 pr_warning("Failed to find probe point in any "
683                                            "functions.\n");
684                                 return -ENOENT;
685                         }
686                 }
687         } else
688                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
689 
690         /* Get the frame base attribute/ops from subprogram */
691         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
692         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
693         if (ret <= 0 || nops == 0) {
694                 pf->fb_ops = NULL;
695 #if _ELFUTILS_PREREQ(0, 142)
696         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
697                    pf->cfi != NULL) {
698                 Dwarf_Frame *frame;
699                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
700                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
701                         pr_warning("Failed to get call frame on 0x%jx\n",
702                                    (uintmax_t)pf->addr);
703                         return -ENOENT;
704                 }
705 #endif
706         }
707 
708         /* Call finder's callback handler */
709         ret = pf->callback(sc_die, pf);
710 
711         /* *pf->fb_ops will be cached in libdw. Don't free it. */
712         pf->fb_ops = NULL;
713 
714         return ret;
715 }
716 
717 struct find_scope_param {
718         const char *function;
719         const char *file;
720         int line;
721         int diff;
722         Dwarf_Die *die_mem;
723         bool found;
724 };
725 
726 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
727 {
728         struct find_scope_param *fsp = data;
729         const char *file;
730         int lno;
731 
732         /* Skip if declared file name does not match */
733         if (fsp->file) {
734                 file = dwarf_decl_file(fn_die);
735                 if (!file || strcmp(fsp->file, file) != 0)
736                         return 0;
737         }
738         /* If the function name is given, that's what user expects */
739         if (fsp->function) {
740                 if (die_match_name(fn_die, fsp->function)) {
741                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
742                         fsp->found = true;
743                         return 1;
744                 }
745         } else {
746                 /* With the line number, find the nearest declared DIE */
747                 dwarf_decl_line(fn_die, &lno);
748                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
749                         /* Keep a candidate and continue */
750                         fsp->diff = fsp->line - lno;
751                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
752                         fsp->found = true;
753                 }
754         }
755         return 0;
756 }
757 
758 /* Find an appropriate scope fits to given conditions */
759 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
760 {
761         struct find_scope_param fsp = {
762                 .function = pf->pev->point.function,
763                 .file = pf->fname,
764                 .line = pf->lno,
765                 .diff = INT_MAX,
766                 .die_mem = die_mem,
767                 .found = false,
768         };
769 
770         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
771 
772         return fsp.found ? die_mem : NULL;
773 }
774 
775 static int probe_point_line_walker(const char *fname, int lineno,
776                                    Dwarf_Addr addr, void *data)
777 {
778         struct probe_finder *pf = data;
779         Dwarf_Die *sc_die, die_mem;
780         int ret;
781 
782         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
783                 return 0;
784 
785         pf->addr = addr;
786         sc_die = find_best_scope(pf, &die_mem);
787         if (!sc_die) {
788                 pr_warning("Failed to find scope of probe point.\n");
789                 return -ENOENT;
790         }
791 
792         ret = call_probe_finder(sc_die, pf);
793 
794         /* Continue if no error, because the line will be in inline function */
795         return ret < 0 ? ret : 0;
796 }
797 
798 /* Find probe point from its line number */
799 static int find_probe_point_by_line(struct probe_finder *pf)
800 {
801         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
802 }
803 
804 /* Find lines which match lazy pattern */
805 static int find_lazy_match_lines(struct intlist *list,
806                                  const char *fname, const char *pat)
807 {
808         FILE *fp;
809         char *line = NULL;
810         size_t line_len;
811         ssize_t len;
812         int count = 0, linenum = 1;
813         char sbuf[STRERR_BUFSIZE];
814 
815         fp = fopen(fname, "r");
816         if (!fp) {
817                 pr_warning("Failed to open %s: %s\n", fname,
818                            strerror_r(errno, sbuf, sizeof(sbuf)));
819                 return -errno;
820         }
821 
822         while ((len = getline(&line, &line_len, fp)) > 0) {
823 
824                 if (line[len - 1] == '\n')
825                         line[len - 1] = '\0';
826 
827                 if (strlazymatch(line, pat)) {
828                         intlist__add(list, linenum);
829                         count++;
830                 }
831                 linenum++;
832         }
833 
834         if (ferror(fp))
835                 count = -errno;
836         free(line);
837         fclose(fp);
838 
839         if (count == 0)
840                 pr_debug("No matched lines found in %s.\n", fname);
841         return count;
842 }
843 
844 static int probe_point_lazy_walker(const char *fname, int lineno,
845                                    Dwarf_Addr addr, void *data)
846 {
847         struct probe_finder *pf = data;
848         Dwarf_Die *sc_die, die_mem;
849         int ret;
850 
851         if (!intlist__has_entry(pf->lcache, lineno) ||
852             strtailcmp(fname, pf->fname) != 0)
853                 return 0;
854 
855         pr_debug("Probe line found: line:%d addr:0x%llx\n",
856                  lineno, (unsigned long long)addr);
857         pf->addr = addr;
858         pf->lno = lineno;
859         sc_die = find_best_scope(pf, &die_mem);
860         if (!sc_die) {
861                 pr_warning("Failed to find scope of probe point.\n");
862                 return -ENOENT;
863         }
864 
865         ret = call_probe_finder(sc_die, pf);
866 
867         /*
868          * Continue if no error, because the lazy pattern will match
869          * to other lines
870          */
871         return ret < 0 ? ret : 0;
872 }
873 
874 /* Find probe points from lazy pattern  */
875 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
876 {
877         int ret = 0;
878         char *fpath;
879 
880         if (intlist__empty(pf->lcache)) {
881                 const char *comp_dir;
882 
883                 comp_dir = cu_get_comp_dir(&pf->cu_die);
884                 ret = get_real_path(pf->fname, comp_dir, &fpath);
885                 if (ret < 0) {
886                         pr_warning("Failed to find source file path.\n");
887                         return ret;
888                 }
889 
890                 /* Matching lazy line pattern */
891                 ret = find_lazy_match_lines(pf->lcache, fpath,
892                                             pf->pev->point.lazy_line);
893                 free(fpath);
894                 if (ret <= 0)
895                         return ret;
896         }
897 
898         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
899 }
900 
901 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
902 {
903         struct probe_finder *pf = data;
904         struct perf_probe_point *pp = &pf->pev->point;
905         Dwarf_Addr addr;
906         int ret;
907 
908         if (pp->lazy_line)
909                 ret = find_probe_point_lazy(in_die, pf);
910         else {
911                 /* Get probe address */
912                 if (dwarf_entrypc(in_die, &addr) != 0) {
913                         pr_warning("Failed to get entry address of %s.\n",
914                                    dwarf_diename(in_die));
915                         return -ENOENT;
916                 }
917                 pf->addr = addr;
918                 pf->addr += pp->offset;
919                 pr_debug("found inline addr: 0x%jx\n",
920                          (uintmax_t)pf->addr);
921 
922                 ret = call_probe_finder(in_die, pf);
923         }
924 
925         return ret;
926 }
927 
928 /* Callback parameter with return value for libdw */
929 struct dwarf_callback_param {
930         void *data;
931         int retval;
932 };
933 
934 /* Search function from function name */
935 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
936 {
937         struct dwarf_callback_param *param = data;
938         struct probe_finder *pf = param->data;
939         struct perf_probe_point *pp = &pf->pev->point;
940 
941         /* Check tag and diename */
942         if (!die_is_func_def(sp_die) ||
943             !die_match_name(sp_die, pp->function))
944                 return DWARF_CB_OK;
945 
946         /* Check declared file */
947         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
948                 return DWARF_CB_OK;
949 
950         pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
951         pf->fname = dwarf_decl_file(sp_die);
952         if (pp->line) { /* Function relative line */
953                 dwarf_decl_line(sp_die, &pf->lno);
954                 pf->lno += pp->line;
955                 param->retval = find_probe_point_by_line(pf);
956         } else if (die_is_func_instance(sp_die)) {
957                 /* Instances always have the entry address */
958                 dwarf_entrypc(sp_die, &pf->addr);
959                 /* Real function */
960                 if (pp->lazy_line)
961                         param->retval = find_probe_point_lazy(sp_die, pf);
962                 else {
963                         pf->addr += pp->offset;
964                         /* TODO: Check the address in this function */
965                         param->retval = call_probe_finder(sp_die, pf);
966                 }
967         } else if (!probe_conf.no_inlines) {
968                 /* Inlined function: search instances */
969                 param->retval = die_walk_instances(sp_die,
970                                         probe_point_inline_cb, (void *)pf);
971                 /* This could be a non-existed inline definition */
972                 if (param->retval == -ENOENT && strisglob(pp->function))
973                         param->retval = 0;
974         }
975 
976         /* We need to find other candidates */
977         if (strisglob(pp->function) && param->retval >= 0) {
978                 param->retval = 0;      /* We have to clear the result */
979                 return DWARF_CB_OK;
980         }
981 
982         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
983 }
984 
985 static int find_probe_point_by_func(struct probe_finder *pf)
986 {
987         struct dwarf_callback_param _param = {.data = (void *)pf,
988                                               .retval = 0};
989         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
990         return _param.retval;
991 }
992 
993 struct pubname_callback_param {
994         char *function;
995         char *file;
996         Dwarf_Die *cu_die;
997         Dwarf_Die *sp_die;
998         int found;
999 };
1000 
1001 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1002 {
1003         struct pubname_callback_param *param = data;
1004 
1005         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1006                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1007                         return DWARF_CB_OK;
1008 
1009                 if (die_match_name(param->sp_die, param->function)) {
1010                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1011                                 return DWARF_CB_OK;
1012 
1013                         if (param->file &&
1014                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1015                                 return DWARF_CB_OK;
1016 
1017                         param->found = 1;
1018                         return DWARF_CB_ABORT;
1019                 }
1020         }
1021 
1022         return DWARF_CB_OK;
1023 }
1024 
1025 /* Find probe points from debuginfo */
1026 static int debuginfo__find_probes(struct debuginfo *dbg,
1027                                   struct probe_finder *pf)
1028 {
1029         struct perf_probe_point *pp = &pf->pev->point;
1030         Dwarf_Off off, noff;
1031         size_t cuhl;
1032         Dwarf_Die *diep;
1033         int ret = 0;
1034 
1035 #if _ELFUTILS_PREREQ(0, 142)
1036         Elf *elf;
1037         GElf_Ehdr ehdr;
1038         GElf_Shdr shdr;
1039 
1040         /* Get the call frame information from this dwarf */
1041         elf = dwarf_getelf(dbg->dbg);
1042         if (elf == NULL)
1043                 return -EINVAL;
1044 
1045         if (gelf_getehdr(elf, &ehdr) == NULL)
1046                 return -EINVAL;
1047 
1048         if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1049             shdr.sh_type == SHT_PROGBITS) {
1050                 pf->cfi = dwarf_getcfi_elf(elf);
1051         } else {
1052                 pf->cfi = dwarf_getcfi(dbg->dbg);
1053         }
1054 #endif
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                         continue;
1089 
1090                 /* Check if target file is included. */
1091                 if (pp->file)
1092                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1093                 else
1094                         pf->fname = NULL;
1095 
1096                 if (!pp->file || pf->fname) {
1097                         if (pp->function)
1098                                 ret = find_probe_point_by_func(pf);
1099                         else if (pp->lazy_line)
1100                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1101                         else {
1102                                 pf->lno = pp->line;
1103                                 ret = find_probe_point_by_line(pf);
1104                         }
1105                         if (ret < 0)
1106                                 break;
1107                 }
1108                 off = noff;
1109         }
1110 
1111 found:
1112         intlist__delete(pf->lcache);
1113         pf->lcache = NULL;
1114 
1115         return ret;
1116 }
1117 
1118 struct local_vars_finder {
1119         struct probe_finder *pf;
1120         struct perf_probe_arg *args;
1121         bool vars;
1122         int max_args;
1123         int nargs;
1124         int ret;
1125 };
1126 
1127 /* Collect available variables in this scope */
1128 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1129 {
1130         struct local_vars_finder *vf = data;
1131         struct probe_finder *pf = vf->pf;
1132         int tag;
1133 
1134         tag = dwarf_tag(die_mem);
1135         if (tag == DW_TAG_formal_parameter ||
1136             (tag == DW_TAG_variable && vf->vars)) {
1137                 if (convert_variable_location(die_mem, vf->pf->addr,
1138                                               vf->pf->fb_ops, &pf->sp_die,
1139                                               NULL) == 0) {
1140                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1141                         if (vf->args[vf->nargs].var == NULL) {
1142                                 vf->ret = -ENOMEM;
1143                                 return DIE_FIND_CB_END;
1144                         }
1145                         pr_debug(" %s", vf->args[vf->nargs].var);
1146                         vf->nargs++;
1147                 }
1148         }
1149 
1150         if (dwarf_haspc(die_mem, vf->pf->addr))
1151                 return DIE_FIND_CB_CONTINUE;
1152         else
1153                 return DIE_FIND_CB_SIBLING;
1154 }
1155 
1156 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1157                              struct perf_probe_arg *args)
1158 {
1159         Dwarf_Die die_mem;
1160         int i;
1161         int n = 0;
1162         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1163                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1164 
1165         for (i = 0; i < pf->pev->nargs; i++) {
1166                 /* var never be NULL */
1167                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1168                         vf.vars = true;
1169                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1170                         /* Copy normal argument */
1171                         args[n] = pf->pev->args[i];
1172                         n++;
1173                         continue;
1174                 }
1175                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1176                 vf.nargs = n;
1177                 /* Special local variables */
1178                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1179                                &die_mem);
1180                 pr_debug(" (%d)\n", vf.nargs - n);
1181                 if (vf.ret < 0)
1182                         return vf.ret;
1183                 n = vf.nargs;
1184         }
1185         return n;
1186 }
1187 
1188 /* Add a found probe point into trace event list */
1189 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1190 {
1191         struct trace_event_finder *tf =
1192                         container_of(pf, struct trace_event_finder, pf);
1193         struct probe_trace_event *tev;
1194         struct perf_probe_arg *args;
1195         int ret, i;
1196 
1197         /* Check number of tevs */
1198         if (tf->ntevs == tf->max_tevs) {
1199                 pr_warning("Too many( > %d) probe point found.\n",
1200                            tf->max_tevs);
1201                 return -ERANGE;
1202         }
1203         tev = &tf->tevs[tf->ntevs++];
1204 
1205         /* Trace point should be converted from subprogram DIE */
1206         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1207                                      pf->pev->point.retprobe, &tev->point);
1208         if (ret < 0)
1209                 return ret;
1210 
1211         tev->point.realname = strdup(dwarf_diename(sc_die));
1212         if (!tev->point.realname)
1213                 return -ENOMEM;
1214 
1215         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1216                  tev->point.offset);
1217 
1218         /* Expand special probe argument if exist */
1219         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1220         if (args == NULL)
1221                 return -ENOMEM;
1222 
1223         ret = expand_probe_args(sc_die, pf, args);
1224         if (ret < 0)
1225                 goto end;
1226 
1227         tev->nargs = ret;
1228         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1229         if (tev->args == NULL) {
1230                 ret = -ENOMEM;
1231                 goto end;
1232         }
1233 
1234         /* Find each argument */
1235         for (i = 0; i < tev->nargs; i++) {
1236                 pf->pvar = &args[i];
1237                 pf->tvar = &tev->args[i];
1238                 /* Variable should be found from scope DIE */
1239                 ret = find_variable(sc_die, pf);
1240                 if (ret != 0)
1241                         break;
1242         }
1243 
1244 end:
1245         free(args);
1246         return ret;
1247 }
1248 
1249 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1250 int debuginfo__find_trace_events(struct debuginfo *dbg,
1251                                  struct perf_probe_event *pev,
1252                                  struct probe_trace_event **tevs)
1253 {
1254         struct trace_event_finder tf = {
1255                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1256                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1257         int ret;
1258 
1259         /* Allocate result tevs array */
1260         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1261         if (*tevs == NULL)
1262                 return -ENOMEM;
1263 
1264         tf.tevs = *tevs;
1265         tf.ntevs = 0;
1266 
1267         ret = debuginfo__find_probes(dbg, &tf.pf);
1268         if (ret < 0) {
1269                 zfree(tevs);
1270                 return ret;
1271         }
1272 
1273         return (ret < 0) ? ret : tf.ntevs;
1274 }
1275 
1276 /* Collect available variables in this scope */
1277 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1278 {
1279         struct available_var_finder *af = data;
1280         struct variable_list *vl;
1281         int tag, ret;
1282 
1283         vl = &af->vls[af->nvls - 1];
1284 
1285         tag = dwarf_tag(die_mem);
1286         if (tag == DW_TAG_formal_parameter ||
1287             tag == DW_TAG_variable) {
1288                 ret = convert_variable_location(die_mem, af->pf.addr,
1289                                                 af->pf.fb_ops, &af->pf.sp_die,
1290                                                 NULL);
1291                 if (ret == 0 || ret == -ERANGE) {
1292                         int ret2;
1293                         bool externs = !af->child;
1294                         struct strbuf buf;
1295 
1296                         strbuf_init(&buf, 64);
1297 
1298                         if (probe_conf.show_location_range) {
1299                                 if (!externs) {
1300                                         if (ret)
1301                                                 strbuf_addf(&buf, "[INV]\t");
1302                                         else
1303                                                 strbuf_addf(&buf, "[VAL]\t");
1304                                 } else
1305                                         strbuf_addf(&buf, "[EXT]\t");
1306                         }
1307 
1308                         ret2 = die_get_varname(die_mem, &buf);
1309 
1310                         if (!ret2 && probe_conf.show_location_range &&
1311                                 !externs) {
1312                                 strbuf_addf(&buf, "\t");
1313                                 ret2 = die_get_var_range(&af->pf.sp_die,
1314                                                         die_mem, &buf);
1315                         }
1316 
1317                         pr_debug("Add new var: %s\n", buf.buf);
1318                         if (ret2 == 0) {
1319                                 strlist__add(vl->vars,
1320                                         strbuf_detach(&buf, NULL));
1321                         }
1322                         strbuf_release(&buf);
1323                 }
1324         }
1325 
1326         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1327                 return DIE_FIND_CB_CONTINUE;
1328         else
1329                 return DIE_FIND_CB_SIBLING;
1330 }
1331 
1332 /* Add a found vars into available variables list */
1333 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1334 {
1335         struct available_var_finder *af =
1336                         container_of(pf, struct available_var_finder, pf);
1337         struct variable_list *vl;
1338         Dwarf_Die die_mem;
1339         int ret;
1340 
1341         /* Check number of tevs */
1342         if (af->nvls == af->max_vls) {
1343                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1344                 return -ERANGE;
1345         }
1346         vl = &af->vls[af->nvls++];
1347 
1348         /* Trace point should be converted from subprogram DIE */
1349         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1350                                      pf->pev->point.retprobe, &vl->point);
1351         if (ret < 0)
1352                 return ret;
1353 
1354         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1355                  vl->point.offset);
1356 
1357         /* Find local variables */
1358         vl->vars = strlist__new(true, NULL);
1359         if (vl->vars == NULL)
1360                 return -ENOMEM;
1361         af->child = true;
1362         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1363 
1364         /* Find external variables */
1365         if (!probe_conf.show_ext_vars)
1366                 goto out;
1367         /* Don't need to search child DIE for external vars. */
1368         af->child = false;
1369         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1370 
1371 out:
1372         if (strlist__empty(vl->vars)) {
1373                 strlist__delete(vl->vars);
1374                 vl->vars = NULL;
1375         }
1376 
1377         return ret;
1378 }
1379 
1380 /*
1381  * Find available variables at given probe point
1382  * Return the number of found probe points. Return 0 if there is no
1383  * matched probe point. Return <0 if an error occurs.
1384  */
1385 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1386                                       struct perf_probe_event *pev,
1387                                       struct variable_list **vls)
1388 {
1389         struct available_var_finder af = {
1390                         .pf = {.pev = pev, .callback = add_available_vars},
1391                         .mod = dbg->mod,
1392                         .max_vls = probe_conf.max_probes};
1393         int ret;
1394 
1395         /* Allocate result vls array */
1396         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1397         if (*vls == NULL)
1398                 return -ENOMEM;
1399 
1400         af.vls = *vls;
1401         af.nvls = 0;
1402 
1403         ret = debuginfo__find_probes(dbg, &af.pf);
1404         if (ret < 0) {
1405                 /* Free vlist for error */
1406                 while (af.nvls--) {
1407                         zfree(&af.vls[af.nvls].point.symbol);
1408                         strlist__delete(af.vls[af.nvls].vars);
1409                 }
1410                 zfree(vls);
1411                 return ret;
1412         }
1413 
1414         return (ret < 0) ? ret : af.nvls;
1415 }
1416 
1417 /* Reverse search */
1418 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1419                                 struct perf_probe_point *ppt)
1420 {
1421         Dwarf_Die cudie, spdie, indie;
1422         Dwarf_Addr _addr = 0, baseaddr = 0;
1423         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1424         int baseline = 0, lineno = 0, ret = 0;
1425 
1426         /* Find cu die */
1427         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1428                 pr_warning("Failed to find debug information for address %lx\n",
1429                            addr);
1430                 ret = -EINVAL;
1431                 goto end;
1432         }
1433 
1434         /* Find a corresponding line (filename and lineno) */
1435         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1436         /* Don't care whether it failed or not */
1437 
1438         /* Find a corresponding function (name, baseline and baseaddr) */
1439         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1440                 /* Get function entry information */
1441                 func = basefunc = dwarf_diename(&spdie);
1442                 if (!func ||
1443                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1444                     dwarf_decl_line(&spdie, &baseline) != 0) {
1445                         lineno = 0;
1446                         goto post;
1447                 }
1448 
1449                 fname = dwarf_decl_file(&spdie);
1450                 if (addr == (unsigned long)baseaddr) {
1451                         /* Function entry - Relative line number is 0 */
1452                         lineno = baseline;
1453                         goto post;
1454                 }
1455 
1456                 /* Track down the inline functions step by step */
1457                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1458                                                 &indie)) {
1459                         /* There is an inline function */
1460                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1461                             _addr == addr) {
1462                                 /*
1463                                  * addr is at an inline function entry.
1464                                  * In this case, lineno should be the call-site
1465                                  * line number. (overwrite lineinfo)
1466                                  */
1467                                 lineno = die_get_call_lineno(&indie);
1468                                 fname = die_get_call_file(&indie);
1469                                 break;
1470                         } else {
1471                                 /*
1472                                  * addr is in an inline function body.
1473                                  * Since lineno points one of the lines
1474                                  * of the inline function, baseline should
1475                                  * be the entry line of the inline function.
1476                                  */
1477                                 tmp = dwarf_diename(&indie);
1478                                 if (!tmp ||
1479                                     dwarf_decl_line(&indie, &baseline) != 0)
1480                                         break;
1481                                 func = tmp;
1482                                 spdie = indie;
1483                         }
1484                 }
1485                 /* Verify the lineno and baseline are in a same file */
1486                 tmp = dwarf_decl_file(&spdie);
1487                 if (!tmp || strcmp(tmp, fname) != 0)
1488                         lineno = 0;
1489         }
1490 
1491 post:
1492         /* Make a relative line number or an offset */
1493         if (lineno)
1494                 ppt->line = lineno - baseline;
1495         else if (basefunc) {
1496                 ppt->offset = addr - (unsigned long)baseaddr;
1497                 func = basefunc;
1498         }
1499 
1500         /* Duplicate strings */
1501         if (func) {
1502                 ppt->function = strdup(func);
1503                 if (ppt->function == NULL) {
1504                         ret = -ENOMEM;
1505                         goto end;
1506                 }
1507         }
1508         if (fname) {
1509                 ppt->file = strdup(fname);
1510                 if (ppt->file == NULL) {
1511                         zfree(&ppt->function);
1512                         ret = -ENOMEM;
1513                         goto end;
1514                 }
1515         }
1516 end:
1517         if (ret == 0 && (fname || func))
1518                 ret = 1;        /* Found a point */
1519         return ret;
1520 }
1521 
1522 /* Add a line and store the src path */
1523 static int line_range_add_line(const char *src, unsigned int lineno,
1524                                struct line_range *lr)
1525 {
1526         /* Copy source path */
1527         if (!lr->path) {
1528                 lr->path = strdup(src);
1529                 if (lr->path == NULL)
1530                         return -ENOMEM;
1531         }
1532         return intlist__add(lr->line_list, lineno);
1533 }
1534 
1535 static int line_range_walk_cb(const char *fname, int lineno,
1536                               Dwarf_Addr addr __maybe_unused,
1537                               void *data)
1538 {
1539         struct line_finder *lf = data;
1540         int err;
1541 
1542         if ((strtailcmp(fname, lf->fname) != 0) ||
1543             (lf->lno_s > lineno || lf->lno_e < lineno))
1544                 return 0;
1545 
1546         err = line_range_add_line(fname, lineno, lf->lr);
1547         if (err < 0 && err != -EEXIST)
1548                 return err;
1549 
1550         return 0;
1551 }
1552 
1553 /* Find line range from its line number */
1554 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1555 {
1556         int ret;
1557 
1558         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1559 
1560         /* Update status */
1561         if (ret >= 0)
1562                 if (!intlist__empty(lf->lr->line_list))
1563                         ret = lf->found = 1;
1564                 else
1565                         ret = 0;        /* Lines are not found */
1566         else {
1567                 zfree(&lf->lr->path);
1568         }
1569         return ret;
1570 }
1571 
1572 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1573 {
1574         int ret = find_line_range_by_line(in_die, data);
1575 
1576         /*
1577          * We have to check all instances of inlined function, because
1578          * some execution paths can be optimized out depends on the
1579          * function argument of instances. However, if an error occurs,
1580          * it should be handled by the caller.
1581          */
1582         return ret < 0 ? ret : 0;
1583 }
1584 
1585 /* Search function definition from function name */
1586 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1587 {
1588         struct dwarf_callback_param *param = data;
1589         struct line_finder *lf = param->data;
1590         struct line_range *lr = lf->lr;
1591 
1592         /* Check declared file */
1593         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1594                 return DWARF_CB_OK;
1595 
1596         if (die_is_func_def(sp_die) &&
1597             die_match_name(sp_die, lr->function)) {
1598                 lf->fname = dwarf_decl_file(sp_die);
1599                 dwarf_decl_line(sp_die, &lr->offset);
1600                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1601                 lf->lno_s = lr->offset + lr->start;
1602                 if (lf->lno_s < 0)      /* Overflow */
1603                         lf->lno_s = INT_MAX;
1604                 lf->lno_e = lr->offset + lr->end;
1605                 if (lf->lno_e < 0)      /* Overflow */
1606                         lf->lno_e = INT_MAX;
1607                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1608                 lr->start = lf->lno_s;
1609                 lr->end = lf->lno_e;
1610                 if (!die_is_func_instance(sp_die))
1611                         param->retval = die_walk_instances(sp_die,
1612                                                 line_range_inline_cb, lf);
1613                 else
1614                         param->retval = find_line_range_by_line(sp_die, lf);
1615                 return DWARF_CB_ABORT;
1616         }
1617         return DWARF_CB_OK;
1618 }
1619 
1620 static int find_line_range_by_func(struct line_finder *lf)
1621 {
1622         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1623         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1624         return param.retval;
1625 }
1626 
1627 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1628 {
1629         struct line_finder lf = {.lr = lr, .found = 0};
1630         int ret = 0;
1631         Dwarf_Off off = 0, noff;
1632         size_t cuhl;
1633         Dwarf_Die *diep;
1634         const char *comp_dir;
1635 
1636         /* Fastpath: lookup by function name from .debug_pubnames section */
1637         if (lr->function) {
1638                 struct pubname_callback_param pubname_param = {
1639                         .function = lr->function, .file = lr->file,
1640                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1641                 struct dwarf_callback_param line_range_param = {
1642                         .data = (void *)&lf, .retval = 0};
1643 
1644                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1645                                   &pubname_param, 0);
1646                 if (pubname_param.found) {
1647                         line_range_search_cb(&lf.sp_die, &line_range_param);
1648                         if (lf.found)
1649                                 goto found;
1650                 }
1651         }
1652 
1653         /* Loop on CUs (Compilation Unit) */
1654         while (!lf.found && ret >= 0) {
1655                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1656                                  NULL, NULL, NULL) != 0)
1657                         break;
1658 
1659                 /* Get the DIE(Debugging Information Entry) of this CU */
1660                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1661                 if (!diep)
1662                         continue;
1663 
1664                 /* Check if target file is included. */
1665                 if (lr->file)
1666                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1667                 else
1668                         lf.fname = 0;
1669 
1670                 if (!lr->file || lf.fname) {
1671                         if (lr->function)
1672                                 ret = find_line_range_by_func(&lf);
1673                         else {
1674                                 lf.lno_s = lr->start;
1675                                 lf.lno_e = lr->end;
1676                                 ret = find_line_range_by_line(NULL, &lf);
1677                         }
1678                 }
1679                 off = noff;
1680         }
1681 
1682 found:
1683         /* Store comp_dir */
1684         if (lf.found) {
1685                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1686                 if (comp_dir) {
1687                         lr->comp_dir = strdup(comp_dir);
1688                         if (!lr->comp_dir)
1689                                 ret = -ENOMEM;
1690                 }
1691         }
1692 
1693         pr_debug("path: %s\n", lr->path);
1694         return (ret < 0) ? ret : lf.found;
1695 }
1696 
1697 /*
1698  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1699  * and chop off leading directories that do not exist. Result is passed back as
1700  * a newly allocated path on success.
1701  * Return 0 if file was found and readable, -errno otherwise.
1702  */
1703 int get_real_path(const char *raw_path, const char *comp_dir,
1704                          char **new_path)
1705 {
1706         const char *prefix = symbol_conf.source_prefix;
1707 
1708         if (!prefix) {
1709                 if (raw_path[0] != '/' && comp_dir)
1710                         /* If not an absolute path, try to use comp_dir */
1711                         prefix = comp_dir;
1712                 else {
1713                         if (access(raw_path, R_OK) == 0) {
1714                                 *new_path = strdup(raw_path);
1715                                 return *new_path ? 0 : -ENOMEM;
1716                         } else
1717                                 return -errno;
1718                 }
1719         }
1720 
1721         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1722         if (!*new_path)
1723                 return -ENOMEM;
1724 
1725         for (;;) {
1726                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1727 
1728                 if (access(*new_path, R_OK) == 0)
1729                         return 0;
1730 
1731                 if (!symbol_conf.source_prefix) {
1732                         /* In case of searching comp_dir, don't retry */
1733                         zfree(new_path);
1734                         return -errno;
1735                 }
1736 
1737                 switch (errno) {
1738                 case ENAMETOOLONG:
1739                 case ENOENT:
1740                 case EROFS:
1741                 case EFAULT:
1742                         raw_path = strchr(++raw_path, '/');
1743                         if (!raw_path) {
1744                                 zfree(new_path);
1745                                 return -ENOENT;
1746                         }
1747                         continue;
1748 
1749                 default:
1750                         zfree(new_path);
1751                         return -errno;
1752                 }
1753         }
1754 }
1755 

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