tools/perf/util/probe-finder.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * probe-finder.c : C expression to kprobe event converter
   4  *
   5  * Written by Masami Hiramatsu <[email protected]>
   6  */
   7
   8 #include <inttypes.h>
   9 #include <sys/utsname.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <fcntl.h>
  13 #include <errno.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <stdarg.h>
  19 #include <dwarf-regs.h>
  20
  21 #include <linux/bitops.h>
  22 #include <linux/zalloc.h>
  23 #include "event.h"
  24 #include "dso.h"
  25 #include "debug.h"
  26 #include "intlist.h"
  27 #include "strbuf.h"
  28 #include "strlist.h"
  29 #include "symbol.h"
  30 #include "probe-finder.h"
  31 #include "probe-file.h"
  32 #include "string2.h"
  33
  34 #ifdef HAVE_DEBUGINFOD_SUPPORT
  35 #include <elfutils/debuginfod.h>
  36 #endif
  37
  38 /* Kprobe tracer basic type is up to u64 */
  39 #define MAX_BASIC_TYPE_BITS     64
  40
  41 /* Dwarf FL wrappers */
  42 static char *debuginfo_path;    /* Currently dummy */
  43
  44 static const Dwfl_Callbacks offline_callbacks = {
  45         .find_debuginfo = dwfl_standard_find_debuginfo,
  46         .debuginfo_path = &debuginfo_path,
  47
  48         .section_address = dwfl_offline_section_address,
  49
  50         /* We use this table for core files too.  */
  51         .find_elf = dwfl_build_id_find_elf,
  52 };
  53
  54 /* Get a Dwarf from offline image */
  55 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  56                                          const char *path)
  57 {
  58         GElf_Addr dummy;
  59         int fd;
  60
  61         fd = open(path, O_RDONLY);
  62         if (fd < 0)
  63                 return fd;
  64
  65         dbg->dwfl = dwfl_begin(&offline_callbacks);
  66         if (!dbg->dwfl)
  67                 goto error;
  68
  69         dwfl_report_begin(dbg->dwfl);
  70         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  71         if (!dbg->mod)
  72                 goto error;
  73
  74         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  75         if (!dbg->dbg)
  76                 goto error;
  77
  78         dwfl_module_build_id(dbg->mod, &dbg->build_id, &dummy);
  79
  80         dwfl_report_end(dbg->dwfl, NULL, NULL);
  81
  82         return 0;
  83 error:
  84         if (dbg->dwfl)
  85                 dwfl_end(dbg->dwfl);
  86         else
  87                 close(fd);
  88         memset(dbg, 0, sizeof(*dbg));
  89
  90         return -ENOENT;
  91 }
  92
  93 static struct debuginfo *__debuginfo__new(const char *path)
  94 {
  95         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  96         if (!dbg)
  97                 return NULL;
  98
  99         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 100                 zfree(&dbg);
 101         if (dbg)
 102                 pr_debug("Open Debuginfo file: %s\n", path);
 103         return dbg;
 104 }
 105
 106 enum dso_binary_type distro_dwarf_types[] = {
 107         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 108         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 109         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 110         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 111         DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO,
 112         DSO_BINARY_TYPE__NOT_FOUND,
 113 };
 114
 115 struct debuginfo *debuginfo__new(const char *path)
 116 {
 117         enum dso_binary_type *type;
 118         char buf[PATH_MAX], nil = '\0';
 119         struct dso *dso;
 120         struct debuginfo *dinfo = NULL;
 121         struct build_id bid;
 122
 123         /* Try to open distro debuginfo files */
 124         dso = dso__new(path);
 125         if (!dso)
 126                 goto out;
 127
 128         /* Set the build id for DSO_BINARY_TYPE__BUILDID_DEBUGINFO */
 129         if (is_regular_file(path) && filename__read_build_id(path, &bid) > 0)
 130                 dso__set_build_id(dso, &bid);
 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 heuristic 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         /* Constant value */
 194         if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
 195             immediate_value_is_supported()) {
 196                 Dwarf_Sword snum;
 197
 198                 if (!tvar)
 199                         return 0;
 200
 201                 dwarf_formsdata(&attr, &snum);
 202                 ret = asprintf(&tvar->value, "\\%ld", (long)snum);
 203
 204                 return ret < 0 ? -ENOMEM : 0;
 205         }
 206
 207         /* TODO: handle more than 1 exprs */
 208         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 209                 return -EINVAL; /* Broken DIE ? */
 210         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 211                 ret = dwarf_entrypc(sp_die, &tmp);
 212                 if (ret)
 213                         return -ENOENT;
 214
 215                 if (probe_conf.show_location_range &&
 216                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 217                         ret2 = -ERANGE;
 218                 } else if (addr != tmp ||
 219                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 220                         return -ENOENT;
 221                 }
 222
 223                 ret = dwarf_highpc(sp_die, &tmp);
 224                 if (ret)
 225                         return -ENOENT;
 226                 /*
 227                  * This is fuzzed by fentry mcount. We try to find the
 228                  * parameter location at the earliest address.
 229                  */
 230                 for (addr += 1; addr <= tmp; addr++) {
 231                         if (dwarf_getlocation_addr(&attr, addr, &op,
 232                                                    &nops, 1) > 0)
 233                                 goto found;
 234                 }
 235                 return -ENOENT;
 236         }
 237 found:
 238         if (nops == 0)
 239                 /* TODO: Support const_value */
 240                 return -ENOENT;
 241
 242         if (op->atom == DW_OP_addr) {
 243 static_var:
 244                 if (!tvar)
 245                         return ret2;
 246                 /* Static variables on memory (not stack), make @varname */
 247                 ret = strlen(dwarf_diename(vr_die));
 248                 tvar->value = zalloc(ret + 2);
 249                 if (tvar->value == NULL)
 250                         return -ENOMEM;
 251                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 252                 tvar->ref = alloc_trace_arg_ref((long)offs);
 253                 if (tvar->ref == NULL)
 254                         return -ENOMEM;
 255                 return ret2;
 256         }
 257
 258         /* If this is based on frame buffer, set the offset */
 259         if (op->atom == DW_OP_fbreg) {
 260                 if (fb_ops == NULL)
 261                         return -ENOTSUP;
 262                 ref = true;
 263                 offs = op->number;
 264                 op = &fb_ops[0];
 265         }
 266
 267         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 268                 regn = op->atom - DW_OP_breg0;
 269                 offs += op->number;
 270                 ref = true;
 271         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 272                 regn = op->atom - DW_OP_reg0;
 273         } else if (op->atom == DW_OP_bregx) {
 274                 regn = op->number;
 275                 offs += op->number2;
 276                 ref = true;
 277         } else if (op->atom == DW_OP_regx) {
 278                 regn = op->number;
 279         } else {
 280                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 281                 return -ENOTSUP;
 282         }
 283
 284         if (!tvar)
 285                 return ret2;
 286
 287         regs = get_dwarf_regstr(regn, machine);
 288         if (!regs) {
 289                 /* This should be a bug in DWARF or this tool */
 290                 pr_warning("Mapping for the register number %u "
 291                            "missing on this architecture.\n", regn);
 292                 return -ENOTSUP;
 293         }
 294
 295         tvar->value = strdup(regs);
 296         if (tvar->value == NULL)
 297                 return -ENOMEM;
 298
 299         if (ref) {
 300                 tvar->ref = alloc_trace_arg_ref((long)offs);
 301                 if (tvar->ref == NULL)
 302                         return -ENOMEM;
 303         }
 304         return ret2;
 305 }
 306
 307 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 308
 309 static int convert_variable_type(Dwarf_Die *vr_die,
 310                                  struct probe_trace_arg *tvar,
 311                                  const char *cast, bool user_access)
 312 {
 313         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 314         Dwarf_Die type;
 315         char buf[16];
 316         char sbuf[STRERR_BUFSIZE];
 317         int bsize, boffs, total;
 318         int ret;
 319         char prefix;
 320
 321         /* TODO: check all types */
 322         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "ustring") &&
 323             strcmp(cast, "x") != 0 &&
 324             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 325                 /* Non string type is OK */
 326                 /* and respect signedness/hexadecimal cast */
 327                 tvar->type = strdup(cast);
 328                 return (tvar->type == NULL) ? -ENOMEM : 0;
 329         }
 330
 331         bsize = dwarf_bitsize(vr_die);
 332         if (bsize > 0) {
 333                 /* This is a bitfield */
 334                 boffs = dwarf_bitoffset(vr_die);
 335                 total = dwarf_bytesize(vr_die);
 336                 if (boffs < 0 || total < 0)
 337                         return -ENOENT;
 338                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 339                                 BYTES_TO_BITS(total));
 340                 goto formatted;
 341         }
 342
 343         if (die_get_real_type(vr_die, &type) == NULL) {
 344                 pr_warning("Failed to get a type information of %s.\n",
 345                            dwarf_diename(vr_die));
 346                 return -ENOENT;
 347         }
 348
 349         pr_debug("%s type is %s.\n",
 350                  dwarf_diename(vr_die), dwarf_diename(&type));
 351
 352         if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
 353                 /* String type */
 354                 ret = dwarf_tag(&type);
 355                 if (ret != DW_TAG_pointer_type &&
 356                     ret != DW_TAG_array_type) {
 357                         pr_warning("Failed to cast into string: "
 358                                    "%s(%s) is not a pointer nor array.\n",
 359                                    dwarf_diename(vr_die), dwarf_diename(&type));
 360                         return -EINVAL;
 361                 }
 362                 if (die_get_real_type(&type, &type) == NULL) {
 363                         pr_warning("Failed to get a type"
 364                                    " information.\n");
 365                         return -ENOENT;
 366                 }
 367                 if (ret == DW_TAG_pointer_type) {
 368                         while (*ref_ptr)
 369                                 ref_ptr = &(*ref_ptr)->next;
 370                         /* Add new reference with offset +0 */
 371                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 372                         if (*ref_ptr == NULL) {
 373                                 pr_warning("Out of memory error\n");
 374                                 return -ENOMEM;
 375                         }
 376                         (*ref_ptr)->user_access = user_access;
 377                 }
 378                 if (!die_compare_name(&type, "char") &&
 379                     !die_compare_name(&type, "unsigned char")) {
 380                         pr_warning("Failed to cast into string: "
 381                                    "%s is not (unsigned) char *.\n",
 382                                    dwarf_diename(vr_die));
 383                         return -EINVAL;
 384                 }
 385                 tvar->type = strdup(cast);
 386                 return (tvar->type == NULL) ? -ENOMEM : 0;
 387         }
 388
 389         if (cast && (strcmp(cast, "u") == 0))
 390                 prefix = 'u';
 391         else if (cast && (strcmp(cast, "s") == 0))
 392                 prefix = 's';
 393         else if (cast && (strcmp(cast, "x") == 0) &&
 394                  probe_type_is_available(PROBE_TYPE_X))
 395                 prefix = 'x';
 396         else
 397                 prefix = die_is_signed_type(&type) ? 's' :
 398                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 399
 400         ret = dwarf_bytesize(&type);
 401         if (ret <= 0)
 402                 /* No size ... try to use default type */
 403                 return 0;
 404         ret = BYTES_TO_BITS(ret);
 405
 406         /* Check the bitwidth */
 407         if (ret > MAX_BASIC_TYPE_BITS) {
 408                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 409                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 410                 ret = MAX_BASIC_TYPE_BITS;
 411         }
 412         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 413
 414 formatted:
 415         if (ret < 0 || ret >= 16) {
 416                 if (ret >= 16)
 417                         ret = -E2BIG;
 418                 pr_warning("Failed to convert variable type: %s\n",
 419                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 420                 return ret;
 421         }
 422         tvar->type = strdup(buf);
 423         if (tvar->type == NULL)
 424                 return -ENOMEM;
 425         return 0;
 426 }
 427
 428 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 429                                     struct perf_probe_arg_field *field,
 430                                     struct probe_trace_arg_ref **ref_ptr,
 431                                     Dwarf_Die *die_mem, bool user_access)
 432 {
 433         struct probe_trace_arg_ref *ref = *ref_ptr;
 434         Dwarf_Die type;
 435         Dwarf_Word offs;
 436         int ret, tag;
 437
 438         pr_debug("converting %s in %s\n", field->name, varname);
 439         if (die_get_real_type(vr_die, &type) == NULL) {
 440                 pr_warning("Failed to get the type of %s.\n", varname);
 441                 return -ENOENT;
 442         }
 443         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 444                   (unsigned)dwarf_dieoffset(&type));
 445         tag = dwarf_tag(&type);
 446
 447         if (field->name[0] == '[' &&
 448             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 449                 /* Save original type for next field or type */
 450                 memcpy(die_mem, &type, sizeof(*die_mem));
 451                 /* Get the type of this array */
 452                 if (die_get_real_type(&type, &type) == NULL) {
 453                         pr_warning("Failed to get the type of %s.\n", varname);
 454                         return -ENOENT;
 455                 }
 456                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 457                          (unsigned)dwarf_dieoffset(&type));
 458                 if (tag == DW_TAG_pointer_type) {
 459                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 460                         if (ref == NULL)
 461                                 return -ENOMEM;
 462                         if (*ref_ptr)
 463                                 (*ref_ptr)->next = ref;
 464                         else
 465                                 *ref_ptr = ref;
 466                 }
 467                 ref->offset += dwarf_bytesize(&type) * field->index;
 468                 ref->user_access = user_access;
 469                 goto next;
 470         } else if (tag == DW_TAG_pointer_type) {
 471                 /* Check the pointer and dereference */
 472                 if (!field->ref) {
 473                         pr_err("Semantic error: %s must be referred by '->'\n",
 474                                field->name);
 475                         return -EINVAL;
 476                 }
 477                 /* Get the type pointed by this pointer */
 478                 if (die_get_real_type(&type, &type) == NULL) {
 479                         pr_warning("Failed to get the type of %s.\n", varname);
 480                         return -ENOENT;
 481                 }
 482                 /* Verify it is a data structure  */
 483                 tag = dwarf_tag(&type);
 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
 490                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 491                 if (ref == NULL)
 492                         return -ENOMEM;
 493                 if (*ref_ptr)
 494                         (*ref_ptr)->next = ref;
 495                 else
 496                         *ref_ptr = ref;
 497         } else {
 498                 /* Verify it is a data structure  */
 499                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 500                         pr_warning("%s is not a data structure nor a union.\n",
 501                                    varname);
 502                         return -EINVAL;
 503                 }
 504                 if (field->name[0] == '[') {
 505                         pr_err("Semantic error: %s is not a pointer"
 506                                " nor array.\n", varname);
 507                         return -EINVAL;
 508                 }
 509                 /* While processing unnamed field, we don't care about this */
 510                 if (field->ref && dwarf_diename(vr_die)) {
 511                         pr_err("Semantic error: %s must be referred by '.'\n",
 512                                field->name);
 513                         return -EINVAL;
 514                 }
 515                 if (!ref) {
 516                         pr_warning("Structure on a register is not "
 517                                    "supported yet.\n");
 518                         return -ENOTSUP;
 519                 }
 520         }
 521
 522         if (die_find_member(&type, field->name, die_mem) == NULL) {
 523                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 524                            dwarf_diename(&type), field->name);
 525                 return -EINVAL;
 526         }
 527
 528         /* Get the offset of the field */
 529         if (tag == DW_TAG_union_type) {
 530                 offs = 0;
 531         } else {
 532                 ret = die_get_data_member_location(die_mem, &offs);
 533                 if (ret < 0) {
 534                         pr_warning("Failed to get the offset of %s.\n",
 535                                    field->name);
 536                         return ret;
 537                 }
 538         }
 539         ref->offset += (long)offs;
 540         ref->user_access = user_access;
 541
 542         /* If this member is unnamed, we need to reuse this field */
 543         if (!dwarf_diename(die_mem))
 544                 return convert_variable_fields(die_mem, varname, field,
 545                                                 &ref, die_mem, user_access);
 546
 547 next:
 548         /* Converting next field */
 549         if (field->next)
 550                 return convert_variable_fields(die_mem, field->name,
 551                                 field->next, &ref, die_mem, user_access);
 552         else
 553                 return 0;
 554 }
 555
 556 static void print_var_not_found(const char *varname)
 557 {
 558         pr_err("Failed to find the location of the '%s' variable at this address.\n"
 559                " Perhaps it has been optimized out.\n"
 560                " Use -V with the --range option to show '%s' location range.\n",
 561                 varname, varname);
 562 }
 563
 564 /* Show a variables in kprobe event format */
 565 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 566 {
 567         Dwarf_Die die_mem;
 568         int ret;
 569
 570         pr_debug("Converting variable %s into trace event.\n",
 571                  dwarf_diename(vr_die));
 572
 573         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 574                                         &pf->sp_die, pf->machine, pf->tvar);
 575         if (ret == -ENOENT && pf->skip_empty_arg)
 576                 /* This can be found in other place. skip it */
 577                 return 0;
 578         if (ret == -ENOENT || ret == -EINVAL) {
 579                 print_var_not_found(pf->pvar->var);
 580         } else if (ret == -ENOTSUP)
 581                 pr_err("Sorry, we don't support this variable location yet.\n");
 582         else if (ret == 0 && pf->pvar->field) {
 583                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 584                                               pf->pvar->field, &pf->tvar->ref,
 585                                               &die_mem, pf->pvar->user_access);
 586                 vr_die = &die_mem;
 587         }
 588         if (ret == 0)
 589                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
 590                                             pf->pvar->user_access);
 591         /* *expr will be cached in libdw. Don't free it. */
 592         return ret;
 593 }
 594
 595 /* Find a variable in a scope DIE */
 596 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 597 {
 598         Dwarf_Die vr_die;
 599         char *buf, *ptr;
 600         int ret = 0;
 601
 602         /* Copy raw parameters */
 603         if (!is_c_varname(pf->pvar->var))
 604                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 605
 606         if (pf->pvar->name)
 607                 pf->tvar->name = strdup(pf->pvar->name);
 608         else {
 609                 buf = synthesize_perf_probe_arg(pf->pvar);
 610                 if (!buf)
 611                         return -ENOMEM;
 612                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 613                 if (ptr)
 614                         *ptr = '_';
 615                 pf->tvar->name = buf;
 616         }
 617         if (pf->tvar->name == NULL)
 618                 return -ENOMEM;
 619
 620         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 621         /* Search child die for local variables and parameters. */
 622         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 623                 /* Search again in global variables */
 624                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 625                                                 0, &vr_die)) {
 626                         if (pf->skip_empty_arg)
 627                                 return 0;
 628                         pr_warning("Failed to find '%s' in this function.\n",
 629                                    pf->pvar->var);
 630                         ret = -ENOENT;
 631                 }
 632         }
 633         if (ret >= 0)
 634                 ret = convert_variable(&vr_die, pf);
 635
 636         return ret;
 637 }
 638
 639 /* Convert subprogram DIE to trace point */
 640 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 641                                   Dwarf_Addr paddr, bool retprobe,
 642                                   const char *function,
 643                                   struct probe_trace_point *tp)
 644 {
 645         Dwarf_Addr eaddr;
 646         GElf_Sym sym;
 647         const char *symbol;
 648
 649         /* Verify the address is correct */
 650         if (!dwarf_haspc(sp_die, paddr)) {
 651                 pr_warning("Specified offset is out of %s\n",
 652                            dwarf_diename(sp_die));
 653                 return -EINVAL;
 654         }
 655
 656         if (dwarf_entrypc(sp_die, &eaddr) == 0) {
 657                 /* If the DIE has entrypc, use it. */
 658                 symbol = dwarf_diename(sp_die);
 659         } else {
 660                 /* Try to get actual symbol name and address from symtab */
 661                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 662                 eaddr = sym.st_value;
 663         }
 664         if (!symbol) {
 665                 pr_warning("Failed to find symbol at 0x%lx\n",
 666                            (unsigned long)paddr);
 667                 return -ENOENT;
 668         }
 669
 670         tp->offset = (unsigned long)(paddr - eaddr);
 671         tp->address = paddr;
 672         tp->symbol = strdup(symbol);
 673         if (!tp->symbol)
 674                 return -ENOMEM;
 675
 676         /* Return probe must be on the head of a subprogram */
 677         if (retprobe) {
 678                 if (eaddr != paddr) {
 679                         pr_warning("Failed to find \"%s%%return\",\n"
 680                                    " because %s is an inlined function and"
 681                                    " has no return point.\n", function,
 682                                    function);
 683                         return -EINVAL;
 684                 }
 685                 tp->retprobe = true;
 686         }
 687
 688         return 0;
 689 }
 690
 691 /* Call probe_finder callback with scope DIE */
 692 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 693 {
 694         Dwarf_Attribute fb_attr;
 695         Dwarf_Frame *frame = NULL;
 696         size_t nops;
 697         int ret;
 698
 699         if (!sc_die) {
 700                 pr_err("Caller must pass a scope DIE. Program error.\n");
 701                 return -EINVAL;
 702         }
 703
 704         /* If not a real subprogram, find a real one */
 705         if (!die_is_func_def(sc_die)) {
 706                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 707                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 708                                 pr_warning("Ignoring tail call from %s\n",
 709                                                 dwarf_diename(&pf->sp_die));
 710                                 return 0;
 711                         } else {
 712                                 pr_warning("Failed to find probe point in any "
 713                                            "functions.\n");
 714                                 return -ENOENT;
 715                         }
 716                 }
 717         } else
 718                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 719
 720         /* Get the frame base attribute/ops from subprogram */
 721         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 722         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 723         if (ret <= 0 || nops == 0) {
 724                 pf->fb_ops = NULL;
 725 #if _ELFUTILS_PREREQ(0, 142)
 726         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 727                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 728                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 729                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 730                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 731                         pr_warning("Failed to get call frame on 0x%jx\n",
 732                                    (uintmax_t)pf->addr);
 733                         free(frame);
 734                         return -ENOENT;
 735                 }
 736 #endif
 737         }
 738
 739         /* Call finder's callback handler */
 740         ret = pf->callback(sc_die, pf);
 741
 742         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 743         free(frame);
 744         pf->fb_ops = NULL;
 745
 746         return ret;
 747 }
 748
 749 struct find_scope_param {
 750         const char *function;
 751         const char *file;
 752         int line;
 753         int diff;
 754         Dwarf_Die *die_mem;
 755         bool found;
 756 };
 757
 758 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 759 {
 760         struct find_scope_param *fsp = data;
 761         const char *file;
 762         int lno;
 763
 764         /* Skip if declared file name does not match */
 765         if (fsp->file) {
 766                 file = die_get_decl_file(fn_die);
 767                 if (!file || strcmp(fsp->file, file) != 0)
 768                         return 0;
 769         }
 770         /* If the function name is given, that's what user expects */
 771         if (fsp->function) {
 772                 if (die_match_name(fn_die, fsp->function)) {
 773                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 774                         fsp->found = true;
 775                         return 1;
 776                 }
 777         } else {
 778                 /* With the line number, find the nearest declared DIE */
 779                 dwarf_decl_line(fn_die, &lno);
 780                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 781                         /* Keep a candidate and continue */
 782                         fsp->diff = fsp->line - lno;
 783                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 784                         fsp->found = true;
 785                 }
 786         }
 787         return 0;
 788 }
 789
 790 /* Return innermost DIE */
 791 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
 792 {
 793         struct find_scope_param *fsp = data;
 794
 795         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 796         fsp->found = true;
 797         return 1;
 798 }
 799
 800 /* Find an appropriate scope fits to given conditions */
 801 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 802 {
 803         struct find_scope_param fsp = {
 804                 .function = pf->pev->point.function,
 805                 .file = pf->fname,
 806                 .line = pf->lno,
 807                 .diff = INT_MAX,
 808                 .die_mem = die_mem,
 809                 .found = false,
 810         };
 811         int ret;
 812
 813         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
 814                                    &fsp);
 815         if (!ret && !fsp.found)
 816                 cu_walk_functions_at(&pf->cu_die, pf->addr,
 817                                      find_inner_scope_cb, &fsp);
 818
 819         return fsp.found ? die_mem : NULL;
 820 }
 821
 822 static int verify_representive_line(struct probe_finder *pf, const char *fname,
 823                                 int lineno, Dwarf_Addr addr)
 824 {
 825         const char *__fname, *__func = NULL;
 826         Dwarf_Die die_mem;
 827         int __lineno;
 828
 829         /* Verify line number and address by reverse search */
 830         if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
 831                 return 0;
 832
 833         pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
 834         if (strcmp(fname, __fname) || lineno == __lineno)
 835                 return 0;
 836
 837         pr_warning("This line is sharing the address with other lines.\n");
 838
 839         if (pf->pev->point.function) {
 840                 /* Find best match function name and lines */
 841                 pf->addr = addr;
 842                 if (find_best_scope(pf, &die_mem)
 843                     && die_match_name(&die_mem, pf->pev->point.function)
 844                     && dwarf_decl_line(&die_mem, &lineno) == 0) {
 845                         __func = dwarf_diename(&die_mem);
 846                         __lineno -= lineno;
 847                 }
 848         }
 849         pr_warning("Please try to probe at %s:%d instead.\n",
 850                    __func ? : __fname, __lineno);
 851
 852         return -ENOENT;
 853 }
 854
 855 static int probe_point_line_walker(const char *fname, int lineno,
 856                                    Dwarf_Addr addr, void *data)
 857 {
 858         struct probe_finder *pf = data;
 859         Dwarf_Die *sc_die, die_mem;
 860         int ret;
 861
 862         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 863                 return 0;
 864
 865         if (verify_representive_line(pf, fname, lineno, addr))
 866                 return -ENOENT;
 867
 868         pf->addr = addr;
 869         sc_die = find_best_scope(pf, &die_mem);
 870         if (!sc_die) {
 871                 pr_warning("Failed to find scope of probe point.\n");
 872                 return -ENOENT;
 873         }
 874
 875         ret = call_probe_finder(sc_die, pf);
 876
 877         /* Continue if no error, because the line will be in inline function */
 878         return ret < 0 ? ret : 0;
 879 }
 880
 881 /* Find probe point from its line number */
 882 static int find_probe_point_by_line(struct probe_finder *pf)
 883 {
 884         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 885 }
 886
 887 /* Find lines which match lazy pattern */
 888 static int find_lazy_match_lines(struct intlist *list,
 889                                  const char *fname, const char *pat)
 890 {
 891         FILE *fp;
 892         char *line = NULL;
 893         size_t line_len;
 894         ssize_t len;
 895         int count = 0, linenum = 1;
 896         char sbuf[STRERR_BUFSIZE];
 897
 898         fp = fopen(fname, "r");
 899         if (!fp) {
 900                 pr_warning("Failed to open %s: %s\n", fname,
 901                            str_error_r(errno, sbuf, sizeof(sbuf)));
 902                 return -errno;
 903         }
 904
 905         while ((len = getline(&line, &line_len, fp)) > 0) {
 906
 907                 if (line[len - 1] == '\n')
 908                         line[len - 1] = '\0';
 909
 910                 if (strlazymatch(line, pat)) {
 911                         intlist__add(list, linenum);
 912                         count++;
 913                 }
 914                 linenum++;
 915         }
 916
 917         if (ferror(fp))
 918                 count = -errno;
 919         free(line);
 920         fclose(fp);
 921
 922         if (count == 0)
 923                 pr_debug("No matched lines found in %s.\n", fname);
 924         return count;
 925 }
 926
 927 static int probe_point_lazy_walker(const char *fname, int lineno,
 928                                    Dwarf_Addr addr, void *data)
 929 {
 930         struct probe_finder *pf = data;
 931         Dwarf_Die *sc_die, die_mem;
 932         int ret;
 933
 934         if (!intlist__has_entry(pf->lcache, lineno) ||
 935             strtailcmp(fname, pf->fname) != 0)
 936                 return 0;
 937
 938         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 939                  lineno, (unsigned long long)addr);
 940         pf->addr = addr;
 941         pf->lno = lineno;
 942         sc_die = find_best_scope(pf, &die_mem);
 943         if (!sc_die) {
 944                 pr_warning("Failed to find scope of probe point.\n");
 945                 return -ENOENT;
 946         }
 947
 948         ret = call_probe_finder(sc_die, pf);
 949
 950         /*
 951          * Continue if no error, because the lazy pattern will match
 952          * to other lines
 953          */
 954         return ret < 0 ? ret : 0;
 955 }
 956
 957 /* Find probe points from lazy pattern  */
 958 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 959 {
 960         struct build_id bid;
 961         char sbuild_id[SBUILD_ID_SIZE] = "";
 962         int ret = 0;
 963         char *fpath;
 964
 965         if (intlist__empty(pf->lcache)) {
 966                 const char *comp_dir;
 967
 968                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 969                 if (pf->dbg->build_id) {
 970                         build_id__init(&bid, pf->dbg->build_id, BUILD_ID_SIZE);
 971                         build_id__sprintf(&bid, sbuild_id);
 972                 }
 973                 ret = find_source_path(pf->fname, sbuild_id, comp_dir, &fpath);
 974                 if (ret < 0) {
 975                         pr_warning("Failed to find source file path.\n");
 976                         return ret;
 977                 }
 978
 979                 /* Matching lazy line pattern */
 980                 ret = find_lazy_match_lines(pf->lcache, fpath,
 981                                             pf->pev->point.lazy_line);
 982                 free(fpath);
 983                 if (ret <= 0)
 984                         return ret;
 985         }
 986
 987         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 988 }
 989
 990 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 991 {
 992         struct perf_probe_point *pp = &pf->pev->point;
 993
 994         /* Not uprobe? */
 995         if (!pf->pev->uprobes)
 996                 return;
 997
 998         /* Compiled with optimization? */
 999         if (die_is_optimized_target(&pf->cu_die))
1000                 return;
1001
1002         /* Don't know entrypc? */
1003         if (!pf->addr)
1004                 return;
1005
1006         /* Only FUNC and FUNC@SRC are eligible. */
1007         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
1008             pp->offset || pp->abs_address)
1009                 return;
1010
1011         /* Not interested in func parameter? */
1012         if (!perf_probe_with_var(pf->pev))
1013                 return;
1014
1015         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
1016                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
1017                 pf->addr);
1018
1019         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
1020 }
1021
1022 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1023 {
1024         struct probe_finder *pf = data;
1025         struct perf_probe_point *pp = &pf->pev->point;
1026         Dwarf_Addr addr;
1027         int ret;
1028
1029         if (pp->lazy_line)
1030                 ret = find_probe_point_lazy(in_die, pf);
1031         else {
1032                 /* Get probe address */
1033                 if (die_entrypc(in_die, &addr) != 0) {
1034                         pr_warning("Failed to get entry address of %s.\n",
1035                                    dwarf_diename(in_die));
1036                         return -ENOENT;
1037                 }
1038                 if (addr == 0) {
1039                         pr_debug("%s has no valid entry address. skipped.\n",
1040                                  dwarf_diename(in_die));
1041                         return -ENOENT;
1042                 }
1043                 pf->addr = addr;
1044                 pf->addr += pp->offset;
1045                 pr_debug("found inline addr: 0x%jx\n",
1046                          (uintmax_t)pf->addr);
1047
1048                 ret = call_probe_finder(in_die, pf);
1049         }
1050
1051         return ret;
1052 }
1053
1054 /* Callback parameter with return value for libdw */
1055 struct dwarf_callback_param {
1056         void *data;
1057         int retval;
1058 };
1059
1060 /* Search function from function name */
1061 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1062 {
1063         struct dwarf_callback_param *param = data;
1064         struct probe_finder *pf = param->data;
1065         struct perf_probe_point *pp = &pf->pev->point;
1066         const char *fname;
1067
1068         /* Check tag and diename */
1069         if (!die_is_func_def(sp_die) ||
1070             !die_match_name(sp_die, pp->function))
1071                 return DWARF_CB_OK;
1072
1073         /* Check declared file */
1074         fname = die_get_decl_file(sp_die);
1075         if (!fname) {
1076                 pr_warning("A function DIE doesn't have decl_line. Maybe broken DWARF?\n");
1077                 return DWARF_CB_OK;
1078         }
1079         if (pp->file && fname && strtailcmp(pp->file, fname))
1080                 return DWARF_CB_OK;
1081
1082         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1083                  (unsigned long)dwarf_dieoffset(sp_die));
1084         pf->fname = fname;
1085         if (pp->line) { /* Function relative line */
1086                 dwarf_decl_line(sp_die, &pf->lno);
1087                 pf->lno += pp->line;
1088                 param->retval = find_probe_point_by_line(pf);
1089         } else if (die_is_func_instance(sp_die)) {
1090                 /* Instances always have the entry address */
1091                 die_entrypc(sp_die, &pf->addr);
1092                 /* But in some case the entry address is 0 */
1093                 if (pf->addr == 0) {
1094                         pr_debug("%s has no entry PC. Skipped\n",
1095                                  dwarf_diename(sp_die));
1096                         param->retval = 0;
1097                 /* Real function */
1098                 } else if (pp->lazy_line)
1099                         param->retval = find_probe_point_lazy(sp_die, pf);
1100                 else {
1101                         skip_prologue(sp_die, pf);
1102                         pf->addr += pp->offset;
1103                         /* TODO: Check the address in this function */
1104                         param->retval = call_probe_finder(sp_die, pf);
1105                 }
1106         } else if (!probe_conf.no_inlines) {
1107                 /* Inlined function: search instances */
1108                 param->retval = die_walk_instances(sp_die,
1109                                         probe_point_inline_cb, (void *)pf);
1110                 /* This could be a non-existed inline definition */
1111                 if (param->retval == -ENOENT)
1112                         param->retval = 0;
1113         }
1114
1115         /* We need to find other candidates */
1116         if (strisglob(pp->function) && param->retval >= 0) {
1117                 param->retval = 0;      /* We have to clear the result */
1118                 return DWARF_CB_OK;
1119         }
1120
1121         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1122 }
1123
1124 static int find_probe_point_by_func(struct probe_finder *pf)
1125 {
1126         struct dwarf_callback_param _param = {.data = (void *)pf,
1127                                               .retval = 0};
1128         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1129         return _param.retval;
1130 }
1131
1132 struct pubname_callback_param {
1133         char *function;
1134         char *file;
1135         Dwarf_Die *cu_die;
1136         Dwarf_Die *sp_die;
1137         int found;
1138 };
1139
1140 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1141 {
1142         struct pubname_callback_param *param = data;
1143         const char *fname;
1144
1145         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1146                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1147                         return DWARF_CB_OK;
1148
1149                 if (die_match_name(param->sp_die, param->function)) {
1150                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1151                                 return DWARF_CB_OK;
1152
1153                         if (param->file) {
1154                                 fname = die_get_decl_file(param->sp_die);
1155                                 if (!fname || strtailcmp(param->file, fname))
1156                                         return DWARF_CB_OK;
1157                         }
1158
1159                         param->found = 1;
1160                         return DWARF_CB_ABORT;
1161                 }
1162         }
1163
1164         return DWARF_CB_OK;
1165 }
1166
1167 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1168                                   struct probe_finder *pf)
1169 {
1170         struct perf_probe_point *pp = &pf->pev->point;
1171         Dwarf_Off off, noff;
1172         size_t cuhl;
1173         Dwarf_Die *diep;
1174         int ret = 0;
1175
1176         off = 0;
1177         pf->lcache = intlist__new(NULL);
1178         if (!pf->lcache)
1179                 return -ENOMEM;
1180
1181         /* Fastpath: lookup by function name from .debug_pubnames section */
1182         if (pp->function && !strisglob(pp->function)) {
1183                 struct pubname_callback_param pubname_param = {
1184                         .function = pp->function,
1185                         .file     = pp->file,
1186                         .cu_die   = &pf->cu_die,
1187                         .sp_die   = &pf->sp_die,
1188                         .found    = 0,
1189                 };
1190                 struct dwarf_callback_param probe_param = {
1191                         .data = pf,
1192                 };
1193
1194                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1195                                   &pubname_param, 0);
1196                 if (pubname_param.found) {
1197                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1198                         if (ret)
1199                                 goto found;
1200                 }
1201         }
1202
1203         /* Loop on CUs (Compilation Unit) */
1204         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1205                 /* Get the DIE(Debugging Information Entry) of this CU */
1206                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1207                 if (!diep) {
1208                         off = noff;
1209                         continue;
1210                 }
1211
1212                 /* Check if target file is included. */
1213                 if (pp->file)
1214                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1215                 else
1216                         pf->fname = NULL;
1217
1218                 if (!pp->file || pf->fname) {
1219                         if (pp->function)
1220                                 ret = find_probe_point_by_func(pf);
1221                         else if (pp->lazy_line)
1222                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1223                         else {
1224                                 pf->lno = pp->line;
1225                                 ret = find_probe_point_by_line(pf);
1226                         }
1227                         if (ret < 0)
1228                                 break;
1229                 }
1230                 off = noff;
1231         }
1232
1233 found:
1234         intlist__delete(pf->lcache);
1235         pf->lcache = NULL;
1236
1237         return ret;
1238 }
1239
1240 /* Find probe points from debuginfo */
1241 static int debuginfo__find_probes(struct debuginfo *dbg,
1242                                   struct probe_finder *pf)
1243 {
1244         int ret = 0;
1245         Elf *elf;
1246         GElf_Ehdr ehdr;
1247
1248         if (pf->cfi_eh || pf->cfi_dbg)
1249                 return debuginfo__find_probe_location(dbg, pf);
1250
1251         /* Get the call frame information from this dwarf */
1252         elf = dwarf_getelf(dbg->dbg);
1253         if (elf == NULL)
1254                 return -EINVAL;
1255
1256         if (gelf_getehdr(elf, &ehdr) == NULL)
1257                 return -EINVAL;
1258
1259         pf->machine = ehdr.e_machine;
1260
1261 #if _ELFUTILS_PREREQ(0, 142)
1262         do {
1263                 GElf_Shdr shdr;
1264
1265                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1266                     shdr.sh_type == SHT_PROGBITS)
1267                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1268
1269                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1270         } while (0);
1271 #endif
1272
1273         ret = debuginfo__find_probe_location(dbg, pf);
1274         return ret;
1275 }
1276
1277 struct local_vars_finder {
1278         struct probe_finder *pf;
1279         struct perf_probe_arg *args;
1280         bool vars;
1281         int max_args;
1282         int nargs;
1283         int ret;
1284 };
1285
1286 /* Collect available variables in this scope */
1287 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1288 {
1289         struct local_vars_finder *vf = data;
1290         struct probe_finder *pf = vf->pf;
1291         int tag;
1292
1293         tag = dwarf_tag(die_mem);
1294         if (tag == DW_TAG_formal_parameter ||
1295             (tag == DW_TAG_variable && vf->vars)) {
1296                 if (convert_variable_location(die_mem, vf->pf->addr,
1297                                               vf->pf->fb_ops, &pf->sp_die,
1298                                               pf->machine, NULL) == 0) {
1299                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1300                         if (vf->args[vf->nargs].var == NULL) {
1301                                 vf->ret = -ENOMEM;
1302                                 return DIE_FIND_CB_END;
1303                         }
1304                         pr_debug(" %s", vf->args[vf->nargs].var);
1305                         vf->nargs++;
1306                 }
1307         }
1308
1309         if (dwarf_haspc(die_mem, vf->pf->addr))
1310                 return DIE_FIND_CB_CONTINUE;
1311         else
1312                 return DIE_FIND_CB_SIBLING;
1313 }
1314
1315 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1316                              struct perf_probe_arg *args)
1317 {
1318         Dwarf_Die die_mem;
1319         int i;
1320         int n = 0;
1321         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1322                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1323
1324         for (i = 0; i < pf->pev->nargs; i++) {
1325                 /* var never be NULL */
1326                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1327                         vf.vars = true;
1328                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1329                         /* Copy normal argument */
1330                         args[n] = pf->pev->args[i];
1331                         n++;
1332                         continue;
1333                 }
1334                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1335                 vf.nargs = n;
1336                 /* Special local variables */
1337                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1338                                &die_mem);
1339                 pr_debug(" (%d)\n", vf.nargs - n);
1340                 if (vf.ret < 0)
1341                         return vf.ret;
1342                 n = vf.nargs;
1343         }
1344         return n;
1345 }
1346
1347 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1348 {
1349         int i;
1350
1351         for (i = 0; i < tf->ntevs; i++) {
1352                 if (tf->pf.addr == tf->tevs[i].point.address)
1353                         return true;
1354         }
1355         return false;
1356 }
1357
1358 /* Add a found probe point into trace event list */
1359 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1360 {
1361         struct trace_event_finder *tf =
1362                         container_of(pf, struct trace_event_finder, pf);
1363         struct perf_probe_point *pp = &pf->pev->point;
1364         struct probe_trace_event *tev;
1365         struct perf_probe_arg *args = NULL;
1366         int ret, i;
1367
1368         /*
1369          * For some reason (e.g. different column assigned to same address)
1370          * This callback can be called with the address which already passed.
1371          * Ignore it first.
1372          */
1373         if (trace_event_finder_overlap(tf))
1374                 return 0;
1375
1376         /* Check number of tevs */
1377         if (tf->ntevs == tf->max_tevs) {
1378                 pr_warning("Too many( > %d) probe point found.\n",
1379                            tf->max_tevs);
1380                 return -ERANGE;
1381         }
1382         tev = &tf->tevs[tf->ntevs++];
1383
1384         /* Trace point should be converted from subprogram DIE */
1385         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1386                                      pp->retprobe, pp->function, &tev->point);
1387         if (ret < 0)
1388                 goto end;
1389
1390         tev->point.realname = strdup(dwarf_diename(sc_die));
1391         if (!tev->point.realname) {
1392                 ret = -ENOMEM;
1393                 goto end;
1394         }
1395
1396         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1397                  tev->point.offset);
1398
1399         /* Expand special probe argument if exist */
1400         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1401         if (args == NULL) {
1402                 ret = -ENOMEM;
1403                 goto end;
1404         }
1405
1406         ret = expand_probe_args(sc_die, pf, args);
1407         if (ret < 0)
1408                 goto end;
1409
1410         tev->nargs = ret;
1411         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1412         if (tev->args == NULL) {
1413                 ret = -ENOMEM;
1414                 goto end;
1415         }
1416
1417         /* Find each argument */
1418         for (i = 0; i < tev->nargs; i++) {
1419                 pf->pvar = &args[i];
1420                 pf->tvar = &tev->args[i];
1421                 /* Variable should be found from scope DIE */
1422                 ret = find_variable(sc_die, pf);
1423                 if (ret != 0)
1424                         break;
1425         }
1426
1427 end:
1428         if (ret) {
1429                 clear_probe_trace_event(tev);
1430                 tf->ntevs--;
1431         }
1432         free(args);
1433         return ret;
1434 }
1435
1436 static int fill_empty_trace_arg(struct perf_probe_event *pev,
1437                                 struct probe_trace_event *tevs, int ntevs)
1438 {
1439         char **valp;
1440         char *type;
1441         int i, j, ret;
1442
1443         if (!ntevs)
1444                 return -ENOENT;
1445
1446         for (i = 0; i < pev->nargs; i++) {
1447                 type = NULL;
1448                 for (j = 0; j < ntevs; j++) {
1449                         if (tevs[j].args[i].value) {
1450                                 type = tevs[j].args[i].type;
1451                                 break;
1452                         }
1453                 }
1454                 if (j == ntevs) {
1455                         print_var_not_found(pev->args[i].var);
1456                         return -ENOENT;
1457                 }
1458                 for (j = 0; j < ntevs; j++) {
1459                         valp = &tevs[j].args[i].value;
1460                         if (*valp)
1461                                 continue;
1462
1463                         ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
1464                         if (ret < 0)
1465                                 return -ENOMEM;
1466                         /* Note that type can be NULL */
1467                         if (type) {
1468                                 tevs[j].args[i].type = strdup(type);
1469                                 if (!tevs[j].args[i].type)
1470                                         return -ENOMEM;
1471                         }
1472                 }
1473         }
1474         return 0;
1475 }
1476
1477 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1478 int debuginfo__find_trace_events(struct debuginfo *dbg,
1479                                  struct perf_probe_event *pev,
1480                                  struct probe_trace_event **tevs)
1481 {
1482         struct trace_event_finder tf = {
1483                         .pf = {.pev = pev, .dbg = dbg, .callback = add_probe_trace_event},
1484                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1485         int ret, i;
1486
1487         /* Allocate result tevs array */
1488         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1489         if (*tevs == NULL)
1490                 return -ENOMEM;
1491
1492         tf.tevs = *tevs;
1493         tf.ntevs = 0;
1494
1495         if (pev->nargs != 0 && immediate_value_is_supported())
1496                 tf.pf.skip_empty_arg = true;
1497
1498         ret = debuginfo__find_probes(dbg, &tf.pf);
1499         if (ret >= 0 && tf.pf.skip_empty_arg)
1500                 ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
1501
1502         if (ret < 0 || tf.ntevs == 0) {
1503                 for (i = 0; i < tf.ntevs; i++)
1504                         clear_probe_trace_event(&tf.tevs[i]);
1505                 zfree(tevs);
1506                 return ret;
1507         }
1508
1509         return (ret < 0) ? ret : tf.ntevs;
1510 }
1511
1512 /* Collect available variables in this scope */
1513 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1514 {
1515         struct available_var_finder *af = data;
1516         struct variable_list *vl;
1517         struct strbuf buf = STRBUF_INIT;
1518         int tag, ret;
1519
1520         vl = &af->vls[af->nvls - 1];
1521
1522         tag = dwarf_tag(die_mem);
1523         if (tag == DW_TAG_formal_parameter ||
1524             tag == DW_TAG_variable) {
1525                 ret = convert_variable_location(die_mem, af->pf.addr,
1526                                                 af->pf.fb_ops, &af->pf.sp_die,
1527                                                 af->pf.machine, NULL);
1528                 if (ret == 0 || ret == -ERANGE) {
1529                         int ret2;
1530                         bool externs = !af->child;
1531
1532                         if (strbuf_init(&buf, 64) < 0)
1533                                 goto error;
1534
1535                         if (probe_conf.show_location_range) {
1536                                 if (!externs)
1537                                         ret2 = strbuf_add(&buf,
1538                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1539                                 else
1540                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1541                                 if (ret2)
1542                                         goto error;
1543                         }
1544
1545                         ret2 = die_get_varname(die_mem, &buf);
1546
1547                         if (!ret2 && probe_conf.show_location_range &&
1548                                 !externs) {
1549                                 if (strbuf_addch(&buf, '\t') < 0)
1550                                         goto error;
1551                                 ret2 = die_get_var_range(&af->pf.sp_die,
1552                                                         die_mem, &buf);
1553                         }
1554
1555                         pr_debug("Add new var: %s\n", buf.buf);
1556                         if (ret2 == 0) {
1557                                 strlist__add(vl->vars,
1558                                         strbuf_detach(&buf, NULL));
1559                         }
1560                         strbuf_release(&buf);
1561                 }
1562         }
1563
1564         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1565                 return DIE_FIND_CB_CONTINUE;
1566         else
1567                 return DIE_FIND_CB_SIBLING;
1568 error:
1569         strbuf_release(&buf);
1570         pr_debug("Error in strbuf\n");
1571         return DIE_FIND_CB_END;
1572 }
1573
1574 static bool available_var_finder_overlap(struct available_var_finder *af)
1575 {
1576         int i;
1577
1578         for (i = 0; i < af->nvls; i++) {
1579                 if (af->pf.addr == af->vls[i].point.address)
1580                         return true;
1581         }
1582         return false;
1583
1584 }
1585
1586 /* Add a found vars into available variables list */
1587 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1588 {
1589         struct available_var_finder *af =
1590                         container_of(pf, struct available_var_finder, pf);
1591         struct perf_probe_point *pp = &pf->pev->point;
1592         struct variable_list *vl;
1593         Dwarf_Die die_mem;
1594         int ret;
1595
1596         /*
1597          * For some reason (e.g. different column assigned to same address),
1598          * this callback can be called with the address which already passed.
1599          * Ignore it first.
1600          */
1601         if (available_var_finder_overlap(af))
1602                 return 0;
1603
1604         /* Check number of tevs */
1605         if (af->nvls == af->max_vls) {
1606                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1607                 return -ERANGE;
1608         }
1609         vl = &af->vls[af->nvls++];
1610
1611         /* Trace point should be converted from subprogram DIE */
1612         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1613                                      pp->retprobe, pp->function, &vl->point);
1614         if (ret < 0)
1615                 return ret;
1616
1617         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1618                  vl->point.offset);
1619
1620         /* Find local variables */
1621         vl->vars = strlist__new(NULL, NULL);
1622         if (vl->vars == NULL)
1623                 return -ENOMEM;
1624         af->child = true;
1625         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1626
1627         /* Find external variables */
1628         if (!probe_conf.show_ext_vars)
1629                 goto out;
1630         /* Don't need to search child DIE for external vars. */
1631         af->child = false;
1632         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1633
1634 out:
1635         if (strlist__empty(vl->vars)) {
1636                 strlist__delete(vl->vars);
1637                 vl->vars = NULL;
1638         }
1639
1640         return ret;
1641 }
1642
1643 /*
1644  * Find available variables at given probe point
1645  * Return the number of found probe points. Return 0 if there is no
1646  * matched probe point. Return <0 if an error occurs.
1647  */
1648 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1649                                       struct perf_probe_event *pev,
1650                                       struct variable_list **vls)
1651 {
1652         struct available_var_finder af = {
1653                         .pf = {.pev = pev, .dbg = dbg, .callback = add_available_vars},
1654                         .mod = dbg->mod,
1655                         .max_vls = probe_conf.max_probes};
1656         int ret;
1657
1658         /* Allocate result vls array */
1659         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1660         if (*vls == NULL)
1661                 return -ENOMEM;
1662
1663         af.vls = *vls;
1664         af.nvls = 0;
1665
1666         ret = debuginfo__find_probes(dbg, &af.pf);
1667         if (ret < 0) {
1668                 /* Free vlist for error */
1669                 while (af.nvls--) {
1670                         zfree(&af.vls[af.nvls].point.symbol);
1671                         strlist__delete(af.vls[af.nvls].vars);
1672                 }
1673                 zfree(vls);
1674                 return ret;
1675         }
1676
1677         return (ret < 0) ? ret : af.nvls;
1678 }
1679
1680 /* For the kernel module, we need a special code to get a DIE */
1681 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1682                                 bool adjust_offset)
1683 {
1684         int n, i;
1685         Elf32_Word shndx;
1686         Elf_Scn *scn;
1687         Elf *elf;
1688         GElf_Shdr mem, *shdr;
1689         const char *p;
1690
1691         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1692         if (!elf)
1693                 return -EINVAL;
1694
1695         /* Get the number of relocations */
1696         n = dwfl_module_relocations(dbg->mod);
1697         if (n < 0)
1698                 return -ENOENT;
1699         /* Search the relocation related .text section */
1700         for (i = 0; i < n; i++) {
1701                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1702                 if (strcmp(p, ".text") == 0) {
1703                         /* OK, get the section header */
1704                         scn = elf_getscn(elf, shndx);
1705                         if (!scn)
1706                                 return -ENOENT;
1707                         shdr = gelf_getshdr(scn, &mem);
1708                         if (!shdr)
1709                                 return -ENOENT;
1710                         *offs = shdr->sh_addr;
1711                         if (adjust_offset)
1712                                 *offs -= shdr->sh_offset;
1713                 }
1714         }
1715         return 0;
1716 }
1717
1718 /* Reverse search */
1719 int debuginfo__find_probe_point(struct debuginfo *dbg, u64 addr,
1720                                 struct perf_probe_point *ppt)
1721 {
1722         Dwarf_Die cudie, spdie, indie;
1723         Dwarf_Addr _addr = 0, baseaddr = 0;
1724         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1725         int baseline = 0, lineno = 0, ret = 0;
1726
1727         /* We always need to relocate the address for aranges */
1728         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1729                 addr += baseaddr;
1730         /* Find cu die */
1731         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1732                 pr_warning("Failed to find debug information for address %#" PRIx64 "\n",
1733                            addr);
1734                 ret = -EINVAL;
1735                 goto end;
1736         }
1737
1738         /* Find a corresponding line (filename and lineno) */
1739         cu_find_lineinfo(&cudie, (Dwarf_Addr)addr, &fname, &lineno);
1740         /* Don't care whether it failed or not */
1741
1742         /* Find a corresponding function (name, baseline and baseaddr) */
1743         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1744                 /* Get function entry information */
1745                 func = basefunc = dwarf_diename(&spdie);
1746                 if (!func ||
1747                     die_entrypc(&spdie, &baseaddr) != 0 ||
1748                     dwarf_decl_line(&spdie, &baseline) != 0) {
1749                         lineno = 0;
1750                         goto post;
1751                 }
1752
1753                 fname = die_get_decl_file(&spdie);
1754                 if (addr == baseaddr) {
1755                         /* Function entry - Relative line number is 0 */
1756                         lineno = baseline;
1757                         goto post;
1758                 }
1759
1760                 /* Track down the inline functions step by step */
1761                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1762                                                 &indie)) {
1763                         /* There is an inline function */
1764                         if (die_entrypc(&indie, &_addr) == 0 &&
1765                             _addr == addr) {
1766                                 /*
1767                                  * addr is at an inline function entry.
1768                                  * In this case, lineno should be the call-site
1769                                  * line number. (overwrite lineinfo)
1770                                  */
1771                                 lineno = die_get_call_lineno(&indie);
1772                                 fname = die_get_call_file(&indie);
1773                                 break;
1774                         } else {
1775                                 /*
1776                                  * addr is in an inline function body.
1777                                  * Since lineno points one of the lines
1778                                  * of the inline function, baseline should
1779                                  * be the entry line of the inline function.
1780                                  */
1781                                 tmp = dwarf_diename(&indie);
1782                                 if (!tmp ||
1783                                     dwarf_decl_line(&indie, &baseline) != 0)
1784                                         break;
1785                                 func = tmp;
1786                                 spdie = indie;
1787                         }
1788                 }
1789                 /* Verify the lineno and baseline are in a same file */
1790                 tmp = die_get_decl_file(&spdie);
1791                 if (!tmp || (fname && strcmp(tmp, fname) != 0))
1792                         lineno = 0;
1793         }
1794
1795 post:
1796         /* Make a relative line number or an offset */
1797         if (lineno)
1798                 ppt->line = lineno - baseline;
1799         else if (basefunc) {
1800                 ppt->offset = addr - baseaddr;
1801                 func = basefunc;
1802         }
1803
1804         /* Duplicate strings */
1805         if (func) {
1806                 ppt->function = strdup(func);
1807                 if (ppt->function == NULL) {
1808                         ret = -ENOMEM;
1809                         goto end;
1810                 }
1811         }
1812         if (fname) {
1813                 ppt->file = strdup(fname);
1814                 if (ppt->file == NULL) {
1815                         zfree(&ppt->function);
1816                         ret = -ENOMEM;
1817                         goto end;
1818                 }
1819         }
1820 end:
1821         if (ret == 0 && (fname || func))
1822                 ret = 1;        /* Found a point */
1823         return ret;
1824 }
1825
1826 /* Add a line and store the src path */
1827 static int line_range_add_line(const char *src, unsigned int lineno,
1828                                struct line_range *lr)
1829 {
1830         /* Copy source path */
1831         if (!lr->path) {
1832                 lr->path = strdup(src);
1833                 if (lr->path == NULL)
1834                         return -ENOMEM;
1835         }
1836         return intlist__add(lr->line_list, lineno);
1837 }
1838
1839 static int line_range_walk_cb(const char *fname, int lineno,
1840                               Dwarf_Addr addr, void *data)
1841 {
1842         struct line_finder *lf = data;
1843         const char *__fname;
1844         int __lineno;
1845         int err;
1846
1847         if ((strtailcmp(fname, lf->fname) != 0) ||
1848             (lf->lno_s > lineno || lf->lno_e < lineno))
1849                 return 0;
1850
1851         /* Make sure this line can be reversible */
1852         if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
1853             && (lineno != __lineno || strcmp(fname, __fname)))
1854                 return 0;
1855
1856         err = line_range_add_line(fname, lineno, lf->lr);
1857         if (err < 0 && err != -EEXIST)
1858                 return err;
1859
1860         return 0;
1861 }
1862
1863 /* Find line range from its line number */
1864 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1865 {
1866         int ret;
1867
1868         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1869
1870         /* Update status */
1871         if (ret >= 0)
1872                 if (!intlist__empty(lf->lr->line_list))
1873                         ret = lf->found = 1;
1874                 else
1875                         ret = 0;        /* Lines are not found */
1876         else {
1877                 zfree(&lf->lr->path);
1878         }
1879         return ret;
1880 }
1881
1882 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1883 {
1884         int ret = find_line_range_by_line(in_die, data);
1885
1886         /*
1887          * We have to check all instances of inlined function, because
1888          * some execution paths can be optimized out depends on the
1889          * function argument of instances. However, if an error occurs,
1890          * it should be handled by the caller.
1891          */
1892         return ret < 0 ? ret : 0;
1893 }
1894
1895 /* Search function definition from function name */
1896 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1897 {
1898         struct dwarf_callback_param *param = data;
1899         struct line_finder *lf = param->data;
1900         struct line_range *lr = lf->lr;
1901         const char *fname;
1902
1903         /* Check declared file */
1904         if (lr->file) {
1905                 fname = die_get_decl_file(sp_die);
1906                 if (!fname || strtailcmp(lr->file, fname))
1907                         return DWARF_CB_OK;
1908         }
1909
1910         if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
1911                 lf->fname = die_get_decl_file(sp_die);
1912                 dwarf_decl_line(sp_die, &lr->offset);
1913                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1914                 lf->lno_s = lr->offset + lr->start;
1915                 if (lf->lno_s < 0)      /* Overflow */
1916                         lf->lno_s = INT_MAX;
1917                 lf->lno_e = lr->offset + lr->end;
1918                 if (lf->lno_e < 0)      /* Overflow */
1919                         lf->lno_e = INT_MAX;
1920                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1921                 lr->start = lf->lno_s;
1922                 lr->end = lf->lno_e;
1923                 if (!die_is_func_instance(sp_die))
1924                         param->retval = die_walk_instances(sp_die,
1925                                                 line_range_inline_cb, lf);
1926                 else
1927                         param->retval = find_line_range_by_line(sp_die, lf);
1928                 return DWARF_CB_ABORT;
1929         }
1930         return DWARF_CB_OK;
1931 }
1932
1933 static int find_line_range_by_func(struct line_finder *lf)
1934 {
1935         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1936         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1937         return param.retval;
1938 }
1939
1940 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1941 {
1942         struct line_finder lf = {.lr = lr, .found = 0};
1943         int ret = 0;
1944         Dwarf_Off off = 0, noff;
1945         size_t cuhl;
1946         Dwarf_Die *diep;
1947         const char *comp_dir;
1948
1949         /* Fastpath: lookup by function name from .debug_pubnames section */
1950         if (lr->function) {
1951                 struct pubname_callback_param pubname_param = {
1952                         .function = lr->function, .file = lr->file,
1953                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1954                 struct dwarf_callback_param line_range_param = {
1955                         .data = (void *)&lf, .retval = 0};
1956
1957                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1958                                   &pubname_param, 0);
1959                 if (pubname_param.found) {
1960                         line_range_search_cb(&lf.sp_die, &line_range_param);
1961                         if (lf.found)
1962                                 goto found;
1963                 }
1964         }
1965
1966         /* Loop on CUs (Compilation Unit) */
1967         while (!lf.found && ret >= 0) {
1968                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1969                                  NULL, NULL, NULL) != 0)
1970                         break;
1971
1972                 /* Get the DIE(Debugging Information Entry) of this CU */
1973                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1974                 if (!diep) {
1975                         off = noff;
1976                         continue;
1977                 }
1978
1979                 /* Check if target file is included. */
1980                 if (lr->file)
1981                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1982                 else
1983                         lf.fname = 0;
1984
1985                 if (!lr->file || lf.fname) {
1986                         if (lr->function)
1987                                 ret = find_line_range_by_func(&lf);
1988                         else {
1989                                 lf.lno_s = lr->start;
1990                                 lf.lno_e = lr->end;
1991                                 ret = find_line_range_by_line(NULL, &lf);
1992                         }
1993                 }
1994                 off = noff;
1995         }
1996
1997 found:
1998         /* Store comp_dir */
1999         if (lf.found) {
2000                 comp_dir = cu_get_comp_dir(&lf.cu_die);
2001                 if (comp_dir) {
2002                         lr->comp_dir = strdup(comp_dir);
2003                         if (!lr->comp_dir)
2004                                 ret = -ENOMEM;
2005                 }
2006         }
2007
2008         pr_debug("path: %s\n", lr->path);
2009         return (ret < 0) ? ret : lf.found;
2010 }
2011
2012 #ifdef HAVE_DEBUGINFOD_SUPPORT
2013 /* debuginfod doesn't require the comp_dir but buildid is required */
2014 static int get_source_from_debuginfod(const char *raw_path,
2015                                 const char *sbuild_id, char **new_path)
2016 {
2017         debuginfod_client *c = debuginfod_begin();
2018         const char *p = raw_path;
2019         int fd;
2020
2021         if (!c)
2022                 return -ENOMEM;
2023
2024         fd = debuginfod_find_source(c, (const unsigned char *)sbuild_id,
2025                                 0, p, new_path);
2026         pr_debug("Search %s from debuginfod -> %d\n", p, fd);
2027         if (fd >= 0)
2028                 close(fd);
2029         debuginfod_end(c);
2030         if (fd < 0) {
2031                 pr_debug("Failed to find %s in debuginfod (%s)\n",
2032                         raw_path, sbuild_id);
2033                 return -ENOENT;
2034         }
2035         pr_debug("Got a source %s\n", *new_path);
2036
2037         return 0;
2038 }
2039 #else
2040 static inline int get_source_from_debuginfod(const char *raw_path __maybe_unused,
2041                                 const char *sbuild_id __maybe_unused,
2042                                 char **new_path __maybe_unused)
2043 {
2044         return -ENOTSUP;
2045 }
2046 #endif
2047 /*
2048  * Find a src file from a DWARF tag path. Prepend optional source path prefix
2049  * and chop off leading directories that do not exist. Result is passed back as
2050  * a newly allocated path on success.
2051  * Return 0 if file was found and readable, -errno otherwise.
2052  */
2053 int find_source_path(const char *raw_path, const char *sbuild_id,
2054                 const char *comp_dir, char **new_path)
2055 {
2056         const char *prefix = symbol_conf.source_prefix;
2057
2058         if (sbuild_id && !prefix) {
2059                 if (!get_source_from_debuginfod(raw_path, sbuild_id, new_path))
2060                         return 0;
2061         }
2062
2063         if (!prefix) {
2064                 if (raw_path[0] != '/' && comp_dir)
2065                         /* If not an absolute path, try to use comp_dir */
2066                         prefix = comp_dir;
2067                 else {
2068                         if (access(raw_path, R_OK) == 0) {
2069                                 *new_path = strdup(raw_path);
2070                                 return *new_path ? 0 : -ENOMEM;
2071                         } else
2072                                 return -errno;
2073                 }
2074         }
2075
2076         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
2077         if (!*new_path)
2078                 return -ENOMEM;
2079
2080         for (;;) {
2081                 sprintf(*new_path, "%s/%s", prefix, raw_path);
2082
2083                 if (access(*new_path, R_OK) == 0)
2084                         return 0;
2085
2086                 if (!symbol_conf.source_prefix) {
2087                         /* In case of searching comp_dir, don't retry */
2088                         zfree(new_path);
2089                         return -errno;
2090                 }
2091
2092                 switch (errno) {
2093                 case ENAMETOOLONG:
2094                 case ENOENT:
2095                 case EROFS:
2096                 case EFAULT:
2097                         raw_path = strchr(++raw_path, '/');
2098                         if (!raw_path) {
2099                                 zfree(new_path);
2100                                 return -ENOENT;
2101                         }
2102                         continue;
2103
2104                 default:
2105                         zfree(new_path);
2106                         return -errno;
2107                 }
2108         }
2109 }