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TOMOYO Linux Cross Reference
Linux/tools/perf/util/probe-finder.c

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

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