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 <mhiramat@redhat.com>
   6  */
   7
   8 #include <inttypes.h>
   9 #include <sys/utsname.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <fcntl.h>
  13 #include <errno.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <stdarg.h>
  19 #include <dwarf-regs.h>
  20
  21 #include <linux/bitops.h>
  22 #include <linux/zalloc.h>
  23 #include "event.h"
  24 #include "dso.h"
  25 #include "debug.h"
  26 #include "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
 122         /* Try to open distro debuginfo files */
 123         dso = dso__new(path);
 124         if (!dso)
 125                 goto out;
 126
 127         for (type = distro_dwarf_types;
 128              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 129              type++) {
 130                 if (dso__read_binary_type_filename(dso, *type, &nil,
 131                                                    buf, PATH_MAX) < 0)
 132                         continue;
 133                 dinfo = __debuginfo__new(buf);
 134         }
 135         dso__put(dso);
 136
 137 out:
 138         /* if failed to open all distro debuginfo, open given binary */
 139         return dinfo ? : __debuginfo__new(path);
 140 }
 141
 142 void debuginfo__delete(struct debuginfo *dbg)
 143 {
 144         if (dbg) {
 145                 if (dbg->dwfl)
 146                         dwfl_end(dbg->dwfl);
 147                 free(dbg);
 148         }
 149 }
 150
 151 /*
 152  * Probe finder related functions
 153  */
 154
 155 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 156 {
 157         struct probe_trace_arg_ref *ref;
 158         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 159         if (ref != NULL)
 160                 ref->offset = offs;
 161         return ref;
 162 }
 163
 164 /*
 165  * Convert a location into trace_arg.
 166  * If tvar == NULL, this just checks variable can be converted.
 167  * If fentry == true and vr_die is a parameter, do huristic search
 168  * for the location fuzzed by function entry mcount.
 169  */
 170 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 171                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 172                                      unsigned int machine,
 173                                      struct probe_trace_arg *tvar)
 174 {
 175         Dwarf_Attribute attr;
 176         Dwarf_Addr tmp = 0;
 177         Dwarf_Op *op;
 178         size_t nops;
 179         unsigned int regn;
 180         Dwarf_Word offs = 0;
 181         bool ref = false;
 182         const char *regs;
 183         int ret, ret2 = 0;
 184
 185         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 186                 goto static_var;
 187
 188         /* Constant value */
 189         if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
 190             immediate_value_is_supported()) {
 191                 Dwarf_Sword snum;
 192
 193                 dwarf_formsdata(&attr, &snum);
 194                 ret = asprintf(&tvar->value, "\\%ld", (long)snum);
 195
 196                 return ret < 0 ? -ENOMEM : 0;
 197         }
 198
 199         /* TODO: handle more than 1 exprs */
 200         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 201                 return -EINVAL; /* Broken DIE ? */
 202         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 203                 ret = dwarf_entrypc(sp_die, &tmp);
 204                 if (ret)
 205                         return -ENOENT;
 206
 207                 if (probe_conf.show_location_range &&
 208                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 209                         ret2 = -ERANGE;
 210                 } else if (addr != tmp ||
 211                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 212                         return -ENOENT;
 213                 }
 214
 215                 ret = dwarf_highpc(sp_die, &tmp);
 216                 if (ret)
 217                         return -ENOENT;
 218                 /*
 219                  * This is fuzzed by fentry mcount. We try to find the
 220                  * parameter location at the earliest address.
 221                  */
 222                 for (addr += 1; addr <= tmp; addr++) {
 223                         if (dwarf_getlocation_addr(&attr, addr, &op,
 224                                                    &nops, 1) > 0)
 225                                 goto found;
 226                 }
 227                 return -ENOENT;
 228         }
 229 found:
 230         if (nops == 0)
 231                 /* TODO: Support const_value */
 232                 return -ENOENT;
 233
 234         if (op->atom == DW_OP_addr) {
 235 static_var:
 236                 if (!tvar)
 237                         return ret2;
 238                 /* Static variables on memory (not stack), make @varname */
 239                 ret = strlen(dwarf_diename(vr_die));
 240                 tvar->value = zalloc(ret + 2);
 241                 if (tvar->value == NULL)
 242                         return -ENOMEM;
 243                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 244                 tvar->ref = alloc_trace_arg_ref((long)offs);
 245                 if (tvar->ref == NULL)
 246                         return -ENOMEM;
 247                 return ret2;
 248         }
 249
 250         /* If this is based on frame buffer, set the offset */
 251         if (op->atom == DW_OP_fbreg) {
 252                 if (fb_ops == NULL)
 253                         return -ENOTSUP;
 254                 ref = true;
 255                 offs = op->number;
 256                 op = &fb_ops[0];
 257         }
 258
 259         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 260                 regn = op->atom - DW_OP_breg0;
 261                 offs += op->number;
 262                 ref = true;
 263         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 264                 regn = op->atom - DW_OP_reg0;
 265         } else if (op->atom == DW_OP_bregx) {
 266                 regn = op->number;
 267                 offs += op->number2;
 268                 ref = true;
 269         } else if (op->atom == DW_OP_regx) {
 270                 regn = op->number;
 271         } else {
 272                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 273                 return -ENOTSUP;
 274         }
 275
 276         if (!tvar)
 277                 return ret2;
 278
 279         regs = get_dwarf_regstr(regn, machine);
 280         if (!regs) {
 281                 /* This should be a bug in DWARF or this tool */
 282                 pr_warning("Mapping for the register number %u "
 283                            "missing on this architecture.\n", regn);
 284                 return -ENOTSUP;
 285         }
 286
 287         tvar->value = strdup(regs);
 288         if (tvar->value == NULL)
 289                 return -ENOMEM;
 290
 291         if (ref) {
 292                 tvar->ref = alloc_trace_arg_ref((long)offs);
 293                 if (tvar->ref == NULL)
 294                         return -ENOMEM;
 295         }
 296         return ret2;
 297 }
 298
 299 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 300
 301 static int convert_variable_type(Dwarf_Die *vr_die,
 302                                  struct probe_trace_arg *tvar,
 303                                  const char *cast, bool user_access)
 304 {
 305         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 306         Dwarf_Die type;
 307         char buf[16];
 308         char sbuf[STRERR_BUFSIZE];
 309         int bsize, boffs, total;
 310         int ret;
 311         char prefix;
 312
 313         /* TODO: check all types */
 314         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "ustring") &&
 315             strcmp(cast, "x") != 0 &&
 316             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 317                 /* Non string type is OK */
 318                 /* and respect signedness/hexadecimal cast */
 319                 tvar->type = strdup(cast);
 320                 return (tvar->type == NULL) ? -ENOMEM : 0;
 321         }
 322
 323         bsize = dwarf_bitsize(vr_die);
 324         if (bsize > 0) {
 325                 /* This is a bitfield */
 326                 boffs = dwarf_bitoffset(vr_die);
 327                 total = dwarf_bytesize(vr_die);
 328                 if (boffs < 0 || total < 0)
 329                         return -ENOENT;
 330                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 331                                 BYTES_TO_BITS(total));
 332                 goto formatted;
 333         }
 334
 335         if (die_get_real_type(vr_die, &type) == NULL) {
 336                 pr_warning("Failed to get a type information of %s.\n",
 337                            dwarf_diename(vr_die));
 338                 return -ENOENT;
 339         }
 340
 341         pr_debug("%s type is %s.\n",
 342                  dwarf_diename(vr_die), dwarf_diename(&type));
 343
 344         if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
 345                 /* String type */
 346                 ret = dwarf_tag(&type);
 347                 if (ret != DW_TAG_pointer_type &&
 348                     ret != DW_TAG_array_type) {
 349                         pr_warning("Failed to cast into string: "
 350                                    "%s(%s) is not a pointer nor array.\n",
 351                                    dwarf_diename(vr_die), dwarf_diename(&type));
 352                         return -EINVAL;
 353                 }
 354                 if (die_get_real_type(&type, &type) == NULL) {
 355                         pr_warning("Failed to get a type"
 356                                    " information.\n");
 357                         return -ENOENT;
 358                 }
 359                 if (ret == DW_TAG_pointer_type) {
 360                         while (*ref_ptr)
 361                                 ref_ptr = &(*ref_ptr)->next;
 362                         /* Add new reference with offset +0 */
 363                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 364                         if (*ref_ptr == NULL) {
 365                                 pr_warning("Out of memory error\n");
 366                                 return -ENOMEM;
 367                         }
 368                         (*ref_ptr)->user_access = user_access;
 369                 }
 370                 if (!die_compare_name(&type, "char") &&
 371                     !die_compare_name(&type, "unsigned char")) {
 372                         pr_warning("Failed to cast into string: "
 373                                    "%s is not (unsigned) char *.\n",
 374                                    dwarf_diename(vr_die));
 375                         return -EINVAL;
 376                 }
 377                 tvar->type = strdup(cast);
 378                 return (tvar->type == NULL) ? -ENOMEM : 0;
 379         }
 380
 381         if (cast && (strcmp(cast, "u") == 0))
 382                 prefix = 'u';
 383         else if (cast && (strcmp(cast, "s") == 0))
 384                 prefix = 's';
 385         else if (cast && (strcmp(cast, "x") == 0) &&
 386                  probe_type_is_available(PROBE_TYPE_X))
 387                 prefix = 'x';
 388         else
 389                 prefix = die_is_signed_type(&type) ? 's' :
 390                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 391
 392         ret = dwarf_bytesize(&type);
 393         if (ret <= 0)
 394                 /* No size ... try to use default type */
 395                 return 0;
 396         ret = BYTES_TO_BITS(ret);
 397
 398         /* Check the bitwidth */
 399         if (ret > MAX_BASIC_TYPE_BITS) {
 400                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 401                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 402                 ret = MAX_BASIC_TYPE_BITS;
 403         }
 404         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 405
 406 formatted:
 407         if (ret < 0 || ret >= 16) {
 408                 if (ret >= 16)
 409                         ret = -E2BIG;
 410                 pr_warning("Failed to convert variable type: %s\n",
 411                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 412                 return ret;
 413         }
 414         tvar->type = strdup(buf);
 415         if (tvar->type == NULL)
 416                 return -ENOMEM;
 417         return 0;
 418 }
 419
 420 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 421                                     struct perf_probe_arg_field *field,
 422                                     struct probe_trace_arg_ref **ref_ptr,
 423                                     Dwarf_Die *die_mem, bool user_access)
 424 {
 425         struct probe_trace_arg_ref *ref = *ref_ptr;
 426         Dwarf_Die type;
 427         Dwarf_Word offs;
 428         int ret, tag;
 429
 430         pr_debug("converting %s in %s\n", field->name, varname);
 431         if (die_get_real_type(vr_die, &type) == NULL) {
 432                 pr_warning("Failed to get the type of %s.\n", varname);
 433                 return -ENOENT;
 434         }
 435         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 436                   (unsigned)dwarf_dieoffset(&type));
 437         tag = dwarf_tag(&type);
 438
 439         if (field->name[0] == '[' &&
 440             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 441                 /* Save original type for next field or type */
 442                 memcpy(die_mem, &type, sizeof(*die_mem));
 443                 /* Get the type of this array */
 444                 if (die_get_real_type(&type, &type) == NULL) {
 445                         pr_warning("Failed to get the type of %s.\n", varname);
 446                         return -ENOENT;
 447                 }
 448                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 449                          (unsigned)dwarf_dieoffset(&type));
 450                 if (tag == DW_TAG_pointer_type) {
 451                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 452                         if (ref == NULL)
 453                                 return -ENOMEM;
 454                         if (*ref_ptr)
 455                                 (*ref_ptr)->next = ref;
 456                         else
 457                                 *ref_ptr = ref;
 458                 }
 459                 ref->offset += dwarf_bytesize(&type) * field->index;
 460                 ref->user_access = user_access;
 461                 goto next;
 462         } else if (tag == DW_TAG_pointer_type) {
 463                 /* Check the pointer and dereference */
 464                 if (!field->ref) {
 465                         pr_err("Semantic error: %s must be referred by '->'\n",
 466                                field->name);
 467                         return -EINVAL;
 468                 }
 469                 /* Get the type pointed by this pointer */
 470                 if (die_get_real_type(&type, &type) == NULL) {
 471                         pr_warning("Failed to get the type of %s.\n", varname);
 472                         return -ENOENT;
 473                 }
 474                 /* Verify it is a data structure  */
 475                 tag = dwarf_tag(&type);
 476                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 477                         pr_warning("%s is not a data structure nor a union.\n",
 478                                    varname);
 479                         return -EINVAL;
 480                 }
 481
 482                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 483                 if (ref == NULL)
 484                         return -ENOMEM;
 485                 if (*ref_ptr)
 486                         (*ref_ptr)->next = ref;
 487                 else
 488                         *ref_ptr = ref;
 489         } else {
 490                 /* Verify it is a data structure  */
 491                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 492                         pr_warning("%s is not a data structure nor a union.\n",
 493                                    varname);
 494                         return -EINVAL;
 495                 }
 496                 if (field->name[0] == '[') {
 497                         pr_err("Semantic error: %s is not a pointer"
 498                                " nor array.\n", varname);
 499                         return -EINVAL;
 500                 }
 501                 /* While prcessing unnamed field, we don't care about this */
 502                 if (field->ref && dwarf_diename(vr_die)) {
 503                         pr_err("Semantic error: %s must be referred by '.'\n",
 504                                field->name);
 505                         return -EINVAL;
 506                 }
 507                 if (!ref) {
 508                         pr_warning("Structure on a register is not "
 509                                    "supported yet.\n");
 510                         return -ENOTSUP;
 511                 }
 512         }
 513
 514         if (die_find_member(&type, field->name, die_mem) == NULL) {
 515                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 516                            dwarf_diename(&type), field->name);
 517                 return -EINVAL;
 518         }
 519
 520         /* Get the offset of the field */
 521         if (tag == DW_TAG_union_type) {
 522                 offs = 0;
 523         } else {
 524                 ret = die_get_data_member_location(die_mem, &offs);
 525                 if (ret < 0) {
 526                         pr_warning("Failed to get the offset of %s.\n",
 527                                    field->name);
 528                         return ret;
 529                 }
 530         }
 531         ref->offset += (long)offs;
 532         ref->user_access = user_access;
 533
 534         /* If this member is unnamed, we need to reuse this field */
 535         if (!dwarf_diename(die_mem))
 536                 return convert_variable_fields(die_mem, varname, field,
 537                                                 &ref, die_mem, user_access);
 538
 539 next:
 540         /* Converting next field */
 541         if (field->next)
 542                 return convert_variable_fields(die_mem, field->name,
 543                                 field->next, &ref, die_mem, user_access);
 544         else
 545                 return 0;
 546 }
 547
 548 static void print_var_not_found(const char *varname)
 549 {
 550         pr_err("Failed to find the location of the '%s' variable at this address.\n"
 551                " Perhaps it has been optimized out.\n"
 552                " Use -V with the --range option to show '%s' location range.\n",
 553                 varname, varname);
 554 }
 555
 556 /* Show a variables in kprobe event format */
 557 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 558 {
 559         Dwarf_Die die_mem;
 560         int ret;
 561
 562         pr_debug("Converting variable %s into trace event.\n",
 563                  dwarf_diename(vr_die));
 564
 565         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 566                                         &pf->sp_die, pf->machine, pf->tvar);
 567         if (ret == -ENOENT && pf->skip_empty_arg)
 568                 /* This can be found in other place. skip it */
 569                 return 0;
 570         if (ret == -ENOENT || ret == -EINVAL) {
 571                 print_var_not_found(pf->pvar->var);
 572         } else if (ret == -ENOTSUP)
 573                 pr_err("Sorry, we don't support this variable location yet.\n");
 574         else if (ret == 0 && pf->pvar->field) {
 575                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 576                                               pf->pvar->field, &pf->tvar->ref,
 577                                               &die_mem, pf->pvar->user_access);
 578                 vr_die = &die_mem;
 579         }
 580         if (ret == 0)
 581                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
 582                                             pf->pvar->user_access);
 583         /* *expr will be cached in libdw. Don't free it. */
 584         return ret;
 585 }
 586
 587 /* Find a variable in a scope DIE */
 588 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 589 {
 590         Dwarf_Die vr_die;
 591         char *buf, *ptr;
 592         int ret = 0;
 593
 594         /* Copy raw parameters */
 595         if (!is_c_varname(pf->pvar->var))
 596                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 597
 598         if (pf->pvar->name)
 599                 pf->tvar->name = strdup(pf->pvar->name);
 600         else {
 601                 buf = synthesize_perf_probe_arg(pf->pvar);
 602                 if (!buf)
 603                         return -ENOMEM;
 604                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 605                 if (ptr)
 606                         *ptr = '_';
 607                 pf->tvar->name = buf;
 608         }
 609         if (pf->tvar->name == NULL)
 610                 return -ENOMEM;
 611
 612         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 613         /* Search child die for local variables and parameters. */
 614         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 615                 /* Search again in global variables */
 616                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 617                                                 0, &vr_die)) {
 618                         if (pf->skip_empty_arg)
 619                                 return 0;
 620                         pr_warning("Failed to find '%s' in this function.\n",
 621                                    pf->pvar->var);
 622                         ret = -ENOENT;
 623                 }
 624         }
 625         if (ret >= 0)
 626                 ret = convert_variable(&vr_die, pf);
 627
 628         return ret;
 629 }
 630
 631 /* Convert subprogram DIE to trace point */
 632 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 633                                   Dwarf_Addr paddr, bool retprobe,
 634                                   const char *function,
 635                                   struct probe_trace_point *tp)
 636 {
 637         Dwarf_Addr eaddr;
 638         GElf_Sym sym;
 639         const char *symbol;
 640
 641         /* Verify the address is correct */
 642         if (!dwarf_haspc(sp_die, paddr)) {
 643                 pr_warning("Specified offset is out of %s\n",
 644                            dwarf_diename(sp_die));
 645                 return -EINVAL;
 646         }
 647
 648         if (dwarf_entrypc(sp_die, &eaddr) == 0) {
 649                 /* If the DIE has entrypc, use it. */
 650                 symbol = dwarf_diename(sp_die);
 651         } else {
 652                 /* Try to get actual symbol name and address from symtab */
 653                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 654                 eaddr = sym.st_value;
 655         }
 656         if (!symbol) {
 657                 pr_warning("Failed to find symbol at 0x%lx\n",
 658                            (unsigned long)paddr);
 659                 return -ENOENT;
 660         }
 661
 662         tp->offset = (unsigned long)(paddr - eaddr);
 663         tp->address = (unsigned long)paddr;
 664         tp->symbol = strdup(symbol);
 665         if (!tp->symbol)
 666                 return -ENOMEM;
 667
 668         /* Return probe must be on the head of a subprogram */
 669         if (retprobe) {
 670                 if (eaddr != paddr) {
 671                         pr_warning("Failed to find \"%s%%return\",\n"
 672                                    " because %s is an inlined function and"
 673                                    " has no return point.\n", function,
 674                                    function);
 675                         return -EINVAL;
 676                 }
 677                 tp->retprobe = true;
 678         }
 679
 680         return 0;
 681 }
 682
 683 /* Call probe_finder callback with scope DIE */
 684 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 685 {
 686         Dwarf_Attribute fb_attr;
 687         Dwarf_Frame *frame = NULL;
 688         size_t nops;
 689         int ret;
 690
 691         if (!sc_die) {
 692                 pr_err("Caller must pass a scope DIE. Program error.\n");
 693                 return -EINVAL;
 694         }
 695
 696         /* If not a real subprogram, find a real one */
 697         if (!die_is_func_def(sc_die)) {
 698                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 699                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 700                                 pr_warning("Ignoring tail call from %s\n",
 701                                                 dwarf_diename(&pf->sp_die));
 702                                 return 0;
 703                         } else {
 704                                 pr_warning("Failed to find probe point in any "
 705                                            "functions.\n");
 706                                 return -ENOENT;
 707                         }
 708                 }
 709         } else
 710                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 711
 712         /* Get the frame base attribute/ops from subprogram */
 713         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 714         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 715         if (ret <= 0 || nops == 0) {
 716                 pf->fb_ops = NULL;
 717 #if _ELFUTILS_PREREQ(0, 142)
 718         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 719                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 720                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 721                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 722                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 723                         pr_warning("Failed to get call frame on 0x%jx\n",
 724                                    (uintmax_t)pf->addr);
 725                         free(frame);
 726                         return -ENOENT;
 727                 }
 728 #endif
 729         }
 730
 731         /* Call finder's callback handler */
 732         ret = pf->callback(sc_die, pf);
 733
 734         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 735         free(frame);
 736         pf->fb_ops = NULL;
 737
 738         return ret;
 739 }
 740
 741 struct find_scope_param {
 742         const char *function;
 743         const char *file;
 744         int line;
 745         int diff;
 746         Dwarf_Die *die_mem;
 747         bool found;
 748 };
 749
 750 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 751 {
 752         struct find_scope_param *fsp = data;
 753         const char *file;
 754         int lno;
 755
 756         /* Skip if declared file name does not match */
 757         if (fsp->file) {
 758                 file = dwarf_decl_file(fn_die);
 759                 if (!file || strcmp(fsp->file, file) != 0)
 760                         return 0;
 761         }
 762         /* If the function name is given, that's what user expects */
 763         if (fsp->function) {
 764                 if (die_match_name(fn_die, fsp->function)) {
 765                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 766                         fsp->found = true;
 767                         return 1;
 768                 }
 769         } else {
 770                 /* With the line number, find the nearest declared DIE */
 771                 dwarf_decl_line(fn_die, &lno);
 772                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 773                         /* Keep a candidate and continue */
 774                         fsp->diff = fsp->line - lno;
 775                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 776                         fsp->found = true;
 777                 }
 778         }
 779         return 0;
 780 }
 781
 782 /* Return innermost DIE */
 783 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
 784 {
 785         struct find_scope_param *fsp = data;
 786
 787         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 788         fsp->found = true;
 789         return 1;
 790 }
 791
 792 /* Find an appropriate scope fits to given conditions */
 793 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 794 {
 795         struct find_scope_param fsp = {
 796                 .function = pf->pev->point.function,
 797                 .file = pf->fname,
 798                 .line = pf->lno,
 799                 .diff = INT_MAX,
 800                 .die_mem = die_mem,
 801                 .found = false,
 802         };
 803         int ret;
 804
 805         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
 806                                    &fsp);
 807         if (!ret && !fsp.found)
 808                 cu_walk_functions_at(&pf->cu_die, pf->addr,
 809                                      find_inner_scope_cb, &fsp);
 810
 811         return fsp.found ? die_mem : NULL;
 812 }
 813
 814 static int verify_representive_line(struct probe_finder *pf, const char *fname,
 815                                 int lineno, Dwarf_Addr addr)
 816 {
 817         const char *__fname, *__func = NULL;
 818         Dwarf_Die die_mem;
 819         int __lineno;
 820
 821         /* Verify line number and address by reverse search */
 822         if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
 823                 return 0;
 824
 825         pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
 826         if (strcmp(fname, __fname) || lineno == __lineno)
 827                 return 0;
 828
 829         pr_warning("This line is sharing the address with other lines.\n");
 830
 831         if (pf->pev->point.function) {
 832                 /* Find best match function name and lines */
 833                 pf->addr = addr;
 834                 if (find_best_scope(pf, &die_mem)
 835                     && die_match_name(&die_mem, pf->pev->point.function)
 836                     && dwarf_decl_line(&die_mem, &lineno) == 0) {
 837                         __func = dwarf_diename(&die_mem);
 838                         __lineno -= lineno;
 839                 }
 840         }
 841         pr_warning("Please try to probe at %s:%d instead.\n",
 842                    __func ? : __fname, __lineno);
 843
 844         return -ENOENT;
 845 }
 846
 847 static int probe_point_line_walker(const char *fname, int lineno,
 848                                    Dwarf_Addr addr, void *data)
 849 {
 850         struct probe_finder *pf = data;
 851         Dwarf_Die *sc_die, die_mem;
 852         int ret;
 853
 854         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 855                 return 0;
 856
 857         if (verify_representive_line(pf, fname, lineno, addr))
 858                 return -ENOENT;
 859
 860         pf->addr = addr;
 861         sc_die = find_best_scope(pf, &die_mem);
 862         if (!sc_die) {
 863                 pr_warning("Failed to find scope of probe point.\n");
 864                 return -ENOENT;
 865         }
 866
 867         ret = call_probe_finder(sc_die, pf);
 868
 869         /* Continue if no error, because the line will be in inline function */
 870         return ret < 0 ? ret : 0;
 871 }
 872
 873 /* Find probe point from its line number */
 874 static int find_probe_point_by_line(struct probe_finder *pf)
 875 {
 876         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 877 }
 878
 879 /* Find lines which match lazy pattern */
 880 static int find_lazy_match_lines(struct intlist *list,
 881                                  const char *fname, const char *pat)
 882 {
 883         FILE *fp;
 884         char *line = NULL;
 885         size_t line_len;
 886         ssize_t len;
 887         int count = 0, linenum = 1;
 888         char sbuf[STRERR_BUFSIZE];
 889
 890         fp = fopen(fname, "r");
 891         if (!fp) {
 892                 pr_warning("Failed to open %s: %s\n", fname,
 893                            str_error_r(errno, sbuf, sizeof(sbuf)));
 894                 return -errno;
 895         }
 896
 897         while ((len = getline(&line, &line_len, fp)) > 0) {
 898
 899                 if (line[len - 1] == '\n')
 900                         line[len - 1] = '\0';
 901
 902                 if (strlazymatch(line, pat)) {
 903                         intlist__add(list, linenum);
 904                         count++;
 905                 }
 906                 linenum++;
 907         }
 908
 909         if (ferror(fp))
 910                 count = -errno;
 911         free(line);
 912         fclose(fp);
 913
 914         if (count == 0)
 915                 pr_debug("No matched lines found in %s.\n", fname);
 916         return count;
 917 }
 918
 919 static int probe_point_lazy_walker(const char *fname, int lineno,
 920                                    Dwarf_Addr addr, void *data)
 921 {
 922         struct probe_finder *pf = data;
 923         Dwarf_Die *sc_die, die_mem;
 924         int ret;
 925
 926         if (!intlist__has_entry(pf->lcache, lineno) ||
 927             strtailcmp(fname, pf->fname) != 0)
 928                 return 0;
 929
 930         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 931                  lineno, (unsigned long long)addr);
 932         pf->addr = addr;
 933         pf->lno = lineno;
 934         sc_die = find_best_scope(pf, &die_mem);
 935         if (!sc_die) {
 936                 pr_warning("Failed to find scope of probe point.\n");
 937                 return -ENOENT;
 938         }
 939
 940         ret = call_probe_finder(sc_die, pf);
 941
 942         /*
 943          * Continue if no error, because the lazy pattern will match
 944          * to other lines
 945          */
 946         return ret < 0 ? ret : 0;
 947 }
 948
 949 /* Find probe points from lazy pattern  */
 950 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 951 {
 952         struct build_id bid;
 953         char sbuild_id[SBUILD_ID_SIZE] = "";
 954         int ret = 0;
 955         char *fpath;
 956
 957         if (intlist__empty(pf->lcache)) {
 958                 const char *comp_dir;
 959
 960                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 961                 if (pf->dbg->build_id) {
 962                         build_id__init(&bid, pf->dbg->build_id, BUILD_ID_SIZE);
 963                         build_id__sprintf(&bid, sbuild_id);
 964                 }
 965                 ret = find_source_path(pf->fname, sbuild_id, comp_dir, &fpath);
 966                 if (ret < 0) {
 967                         pr_warning("Failed to find source file path.\n");
 968                         return ret;
 969                 }
 970
 971                 /* Matching lazy line pattern */
 972                 ret = find_lazy_match_lines(pf->lcache, fpath,
 973                                             pf->pev->point.lazy_line);
 974                 free(fpath);
 975                 if (ret <= 0)
 976                         return ret;
 977         }
 978
 979         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 980 }
 981
 982 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 983 {
 984         struct perf_probe_point *pp = &pf->pev->point;
 985
 986         /* Not uprobe? */
 987         if (!pf->pev->uprobes)
 988                 return;
 989
 990         /* Compiled with optimization? */
 991         if (die_is_optimized_target(&pf->cu_die))
 992                 return;
 993
 994         /* Don't know entrypc? */
 995         if (!pf->addr)
 996                 return;
 997
 998         /* Only FUNC and FUNC@SRC are eligible. */
 999         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
1000             pp->offset || pp->abs_address)
1001                 return;
1002
1003         /* Not interested in func parameter? */
1004         if (!perf_probe_with_var(pf->pev))
1005                 return;
1006
1007         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
1008                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
1009                 pf->addr);
1010
1011         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
1012 }
1013
1014 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1015 {
1016         struct probe_finder *pf = data;
1017         struct perf_probe_point *pp = &pf->pev->point;
1018         Dwarf_Addr addr;
1019         int ret;
1020
1021         if (pp->lazy_line)
1022                 ret = find_probe_point_lazy(in_die, pf);
1023         else {
1024                 /* Get probe address */
1025                 if (die_entrypc(in_die, &addr) != 0) {
1026                         pr_warning("Failed to get entry address of %s.\n",
1027                                    dwarf_diename(in_die));
1028                         return -ENOENT;
1029                 }
1030                 if (addr == 0) {
1031                         pr_debug("%s has no valid entry address. skipped.\n",
1032                                  dwarf_diename(in_die));
1033                         return -ENOENT;
1034                 }
1035                 pf->addr = addr;
1036                 pf->addr += pp->offset;
1037                 pr_debug("found inline addr: 0x%jx\n",
1038                          (uintmax_t)pf->addr);
1039
1040                 ret = call_probe_finder(in_die, pf);
1041         }
1042
1043         return ret;
1044 }
1045
1046 /* Callback parameter with return value for libdw */
1047 struct dwarf_callback_param {
1048         void *data;
1049         int retval;
1050 };
1051
1052 /* Search function from function name */
1053 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1054 {
1055         struct dwarf_callback_param *param = data;
1056         struct probe_finder *pf = param->data;
1057         struct perf_probe_point *pp = &pf->pev->point;
1058
1059         /* Check tag and diename */
1060         if (!die_is_func_def(sp_die) ||
1061             !die_match_name(sp_die, pp->function))
1062                 return DWARF_CB_OK;
1063
1064         /* Check declared file */
1065         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1066                 return DWARF_CB_OK;
1067
1068         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1069                  (unsigned long)dwarf_dieoffset(sp_die));
1070         pf->fname = dwarf_decl_file(sp_die);
1071         if (pp->line) { /* Function relative line */
1072                 dwarf_decl_line(sp_die, &pf->lno);
1073                 pf->lno += pp->line;
1074                 param->retval = find_probe_point_by_line(pf);
1075         } else if (die_is_func_instance(sp_die)) {
1076                 /* Instances always have the entry address */
1077                 die_entrypc(sp_die, &pf->addr);
1078                 /* But in some case the entry address is 0 */
1079                 if (pf->addr == 0) {
1080                         pr_debug("%s has no entry PC. Skipped\n",
1081                                  dwarf_diename(sp_die));
1082                         param->retval = 0;
1083                 /* Real function */
1084                 } else if (pp->lazy_line)
1085                         param->retval = find_probe_point_lazy(sp_die, pf);
1086                 else {
1087                         skip_prologue(sp_die, pf);
1088                         pf->addr += pp->offset;
1089                         /* TODO: Check the address in this function */
1090                         param->retval = call_probe_finder(sp_die, pf);
1091                 }
1092         } else if (!probe_conf.no_inlines) {
1093                 /* Inlined function: search instances */
1094                 param->retval = die_walk_instances(sp_die,
1095                                         probe_point_inline_cb, (void *)pf);
1096                 /* This could be a non-existed inline definition */
1097                 if (param->retval == -ENOENT)
1098                         param->retval = 0;
1099         }
1100
1101         /* We need to find other candidates */
1102         if (strisglob(pp->function) && param->retval >= 0) {
1103                 param->retval = 0;      /* We have to clear the result */
1104                 return DWARF_CB_OK;
1105         }
1106
1107         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1108 }
1109
1110 static int find_probe_point_by_func(struct probe_finder *pf)
1111 {
1112         struct dwarf_callback_param _param = {.data = (void *)pf,
1113                                               .retval = 0};
1114         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1115         return _param.retval;
1116 }
1117
1118 struct pubname_callback_param {
1119         char *function;
1120         char *file;
1121         Dwarf_Die *cu_die;
1122         Dwarf_Die *sp_die;
1123         int found;
1124 };
1125
1126 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1127 {
1128         struct pubname_callback_param *param = data;
1129
1130         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1131                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1132                         return DWARF_CB_OK;
1133
1134                 if (die_match_name(param->sp_die, param->function)) {
1135                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1136                                 return DWARF_CB_OK;
1137
1138                         if (param->file &&
1139                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1140                                 return DWARF_CB_OK;
1141
1142                         param->found = 1;
1143                         return DWARF_CB_ABORT;
1144                 }
1145         }
1146
1147         return DWARF_CB_OK;
1148 }
1149
1150 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1151                                   struct probe_finder *pf)
1152 {
1153         struct perf_probe_point *pp = &pf->pev->point;
1154         Dwarf_Off off, noff;
1155         size_t cuhl;
1156         Dwarf_Die *diep;
1157         int ret = 0;
1158
1159         off = 0;
1160         pf->lcache = intlist__new(NULL);
1161         if (!pf->lcache)
1162                 return -ENOMEM;
1163
1164         /* Fastpath: lookup by function name from .debug_pubnames section */
1165         if (pp->function && !strisglob(pp->function)) {
1166                 struct pubname_callback_param pubname_param = {
1167                         .function = pp->function,
1168                         .file     = pp->file,
1169                         .cu_die   = &pf->cu_die,
1170                         .sp_die   = &pf->sp_die,
1171                         .found    = 0,
1172                 };
1173                 struct dwarf_callback_param probe_param = {
1174                         .data = pf,
1175                 };
1176
1177                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1178                                   &pubname_param, 0);
1179                 if (pubname_param.found) {
1180                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1181                         if (ret)
1182                                 goto found;
1183                 }
1184         }
1185
1186         /* Loop on CUs (Compilation Unit) */
1187         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1188                 /* Get the DIE(Debugging Information Entry) of this CU */
1189                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1190                 if (!diep)
1191                         continue;
1192
1193                 /* Check if target file is included. */
1194                 if (pp->file)
1195                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1196                 else
1197                         pf->fname = NULL;
1198
1199                 if (!pp->file || pf->fname) {
1200                         if (pp->function)
1201                                 ret = find_probe_point_by_func(pf);
1202                         else if (pp->lazy_line)
1203                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1204                         else {
1205                                 pf->lno = pp->line;
1206                                 ret = find_probe_point_by_line(pf);
1207                         }
1208                         if (ret < 0)
1209                                 break;
1210                 }
1211                 off = noff;
1212         }
1213
1214 found:
1215         intlist__delete(pf->lcache);
1216         pf->lcache = NULL;
1217
1218         return ret;
1219 }
1220
1221 /* Find probe points from debuginfo */
1222 static int debuginfo__find_probes(struct debuginfo *dbg,
1223                                   struct probe_finder *pf)
1224 {
1225         int ret = 0;
1226         Elf *elf;
1227         GElf_Ehdr ehdr;
1228
1229         if (pf->cfi_eh || pf->cfi_dbg)
1230                 return debuginfo__find_probe_location(dbg, pf);
1231
1232         /* Get the call frame information from this dwarf */
1233         elf = dwarf_getelf(dbg->dbg);
1234         if (elf == NULL)
1235                 return -EINVAL;
1236
1237         if (gelf_getehdr(elf, &ehdr) == NULL)
1238                 return -EINVAL;
1239
1240         pf->machine = ehdr.e_machine;
1241
1242 #if _ELFUTILS_PREREQ(0, 142)
1243         do {
1244                 GElf_Shdr shdr;
1245
1246                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1247                     shdr.sh_type == SHT_PROGBITS)
1248                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1249
1250                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1251         } while (0);
1252 #endif
1253
1254         ret = debuginfo__find_probe_location(dbg, pf);
1255         return ret;
1256 }
1257
1258 struct local_vars_finder {
1259         struct probe_finder *pf;
1260         struct perf_probe_arg *args;
1261         bool vars;
1262         int max_args;
1263         int nargs;
1264         int ret;
1265 };
1266
1267 /* Collect available variables in this scope */
1268 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1269 {
1270         struct local_vars_finder *vf = data;
1271         struct probe_finder *pf = vf->pf;
1272         int tag;
1273
1274         tag = dwarf_tag(die_mem);
1275         if (tag == DW_TAG_formal_parameter ||
1276             (tag == DW_TAG_variable && vf->vars)) {
1277                 if (convert_variable_location(die_mem, vf->pf->addr,
1278                                               vf->pf->fb_ops, &pf->sp_die,
1279                                               pf->machine, NULL) == 0) {
1280                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1281                         if (vf->args[vf->nargs].var == NULL) {
1282                                 vf->ret = -ENOMEM;
1283                                 return DIE_FIND_CB_END;
1284                         }
1285                         pr_debug(" %s", vf->args[vf->nargs].var);
1286                         vf->nargs++;
1287                 }
1288         }
1289
1290         if (dwarf_haspc(die_mem, vf->pf->addr))
1291                 return DIE_FIND_CB_CONTINUE;
1292         else
1293                 return DIE_FIND_CB_SIBLING;
1294 }
1295
1296 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1297                              struct perf_probe_arg *args)
1298 {
1299         Dwarf_Die die_mem;
1300         int i;
1301         int n = 0;
1302         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1303                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1304
1305         for (i = 0; i < pf->pev->nargs; i++) {
1306                 /* var never be NULL */
1307                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1308                         vf.vars = true;
1309                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1310                         /* Copy normal argument */
1311                         args[n] = pf->pev->args[i];
1312                         n++;
1313                         continue;
1314                 }
1315                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1316                 vf.nargs = n;
1317                 /* Special local variables */
1318                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1319                                &die_mem);
1320                 pr_debug(" (%d)\n", vf.nargs - n);
1321                 if (vf.ret < 0)
1322                         return vf.ret;
1323                 n = vf.nargs;
1324         }
1325         return n;
1326 }
1327
1328 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1329 {
1330         int i;
1331
1332         for (i = 0; i < tf->ntevs; i++) {
1333                 if (tf->pf.addr == tf->tevs[i].point.address)
1334                         return true;
1335         }
1336         return false;
1337 }
1338
1339 /* Add a found probe point into trace event list */
1340 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1341 {
1342         struct trace_event_finder *tf =
1343                         container_of(pf, struct trace_event_finder, pf);
1344         struct perf_probe_point *pp = &pf->pev->point;
1345         struct probe_trace_event *tev;
1346         struct perf_probe_arg *args = NULL;
1347         int ret, i;
1348
1349         /*
1350          * For some reason (e.g. different column assigned to same address)
1351          * This callback can be called with the address which already passed.
1352          * Ignore it first.
1353          */
1354         if (trace_event_finder_overlap(tf))
1355                 return 0;
1356
1357         /* Check number of tevs */
1358         if (tf->ntevs == tf->max_tevs) {
1359                 pr_warning("Too many( > %d) probe point found.\n",
1360                            tf->max_tevs);
1361                 return -ERANGE;
1362         }
1363         tev = &tf->tevs[tf->ntevs++];
1364
1365         /* Trace point should be converted from subprogram DIE */
1366         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1367                                      pp->retprobe, pp->function, &tev->point);
1368         if (ret < 0)
1369                 goto end;
1370
1371         tev->point.realname = strdup(dwarf_diename(sc_die));
1372         if (!tev->point.realname) {
1373                 ret = -ENOMEM;
1374                 goto end;
1375         }
1376
1377         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1378                  tev->point.offset);
1379
1380         /* Expand special probe argument if exist */
1381         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1382         if (args == NULL) {
1383                 ret = -ENOMEM;
1384                 goto end;
1385         }
1386
1387         ret = expand_probe_args(sc_die, pf, args);
1388         if (ret < 0)
1389                 goto end;
1390
1391         tev->nargs = ret;
1392         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1393         if (tev->args == NULL) {
1394                 ret = -ENOMEM;
1395                 goto end;
1396         }
1397
1398         /* Find each argument */
1399         for (i = 0; i < tev->nargs; i++) {
1400                 pf->pvar = &args[i];
1401                 pf->tvar = &tev->args[i];
1402                 /* Variable should be found from scope DIE */
1403                 ret = find_variable(sc_die, pf);
1404                 if (ret != 0)
1405                         break;
1406         }
1407
1408 end:
1409         if (ret) {
1410                 clear_probe_trace_event(tev);
1411                 tf->ntevs--;
1412         }
1413         free(args);
1414         return ret;
1415 }
1416
1417 static int fill_empty_trace_arg(struct perf_probe_event *pev,
1418                                 struct probe_trace_event *tevs, int ntevs)
1419 {
1420         char **valp;
1421         char *type;
1422         int i, j, ret;
1423
1424         if (!ntevs)
1425                 return -ENOENT;
1426
1427         for (i = 0; i < pev->nargs; i++) {
1428                 type = NULL;
1429                 for (j = 0; j < ntevs; j++) {
1430                         if (tevs[j].args[i].value) {
1431                                 type = tevs[j].args[i].type;
1432                                 break;
1433                         }
1434                 }
1435                 if (j == ntevs) {
1436                         print_var_not_found(pev->args[i].var);
1437                         return -ENOENT;
1438                 }
1439                 for (j = 0; j < ntevs; j++) {
1440                         valp = &tevs[j].args[i].value;
1441                         if (*valp)
1442                                 continue;
1443
1444                         ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
1445                         if (ret < 0)
1446                                 return -ENOMEM;
1447                         /* Note that type can be NULL */
1448                         if (type) {
1449                                 tevs[j].args[i].type = strdup(type);
1450                                 if (!tevs[j].args[i].type)
1451                                         return -ENOMEM;
1452                         }
1453                 }
1454         }
1455         return 0;
1456 }
1457
1458 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1459 int debuginfo__find_trace_events(struct debuginfo *dbg,
1460                                  struct perf_probe_event *pev,
1461                                  struct probe_trace_event **tevs)
1462 {
1463         struct trace_event_finder tf = {
1464                         .pf = {.pev = pev, .dbg = dbg, .callback = add_probe_trace_event},
1465                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1466         int ret, i;
1467
1468         /* Allocate result tevs array */
1469         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1470         if (*tevs == NULL)
1471                 return -ENOMEM;
1472
1473         tf.tevs = *tevs;
1474         tf.ntevs = 0;
1475
1476         if (pev->nargs != 0 && immediate_value_is_supported())
1477                 tf.pf.skip_empty_arg = true;
1478
1479         ret = debuginfo__find_probes(dbg, &tf.pf);
1480         if (ret >= 0 && tf.pf.skip_empty_arg)
1481                 ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
1482
1483         if (ret < 0 || tf.ntevs == 0) {
1484                 for (i = 0; i < tf.ntevs; i++)
1485                         clear_probe_trace_event(&tf.tevs[i]);
1486                 zfree(tevs);
1487                 return ret;
1488         }
1489
1490         return (ret < 0) ? ret : tf.ntevs;
1491 }
1492
1493 /* Collect available variables in this scope */
1494 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1495 {
1496         struct available_var_finder *af = data;
1497         struct variable_list *vl;
1498         struct strbuf buf = STRBUF_INIT;
1499         int tag, ret;
1500
1501         vl = &af->vls[af->nvls - 1];
1502
1503         tag = dwarf_tag(die_mem);
1504         if (tag == DW_TAG_formal_parameter ||
1505             tag == DW_TAG_variable) {
1506                 ret = convert_variable_location(die_mem, af->pf.addr,
1507                                                 af->pf.fb_ops, &af->pf.sp_die,
1508                                                 af->pf.machine, NULL);
1509                 if (ret == 0 || ret == -ERANGE) {
1510                         int ret2;
1511                         bool externs = !af->child;
1512
1513                         if (strbuf_init(&buf, 64) < 0)
1514                                 goto error;
1515
1516                         if (probe_conf.show_location_range) {
1517                                 if (!externs)
1518                                         ret2 = strbuf_add(&buf,
1519                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1520                                 else
1521                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1522                                 if (ret2)
1523                                         goto error;
1524                         }
1525
1526                         ret2 = die_get_varname(die_mem, &buf);
1527
1528                         if (!ret2 && probe_conf.show_location_range &&
1529                                 !externs) {
1530                                 if (strbuf_addch(&buf, '\t') < 0)
1531                                         goto error;
1532                                 ret2 = die_get_var_range(&af->pf.sp_die,
1533                                                         die_mem, &buf);
1534                         }
1535
1536                         pr_debug("Add new var: %s\n", buf.buf);
1537                         if (ret2 == 0) {
1538                                 strlist__add(vl->vars,
1539                                         strbuf_detach(&buf, NULL));
1540                         }
1541                         strbuf_release(&buf);
1542                 }
1543         }
1544
1545         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1546                 return DIE_FIND_CB_CONTINUE;
1547         else
1548                 return DIE_FIND_CB_SIBLING;
1549 error:
1550         strbuf_release(&buf);
1551         pr_debug("Error in strbuf\n");
1552         return DIE_FIND_CB_END;
1553 }
1554
1555 static bool available_var_finder_overlap(struct available_var_finder *af)
1556 {
1557         int i;
1558
1559         for (i = 0; i < af->nvls; i++) {
1560                 if (af->pf.addr == af->vls[i].point.address)
1561                         return true;
1562         }
1563         return false;
1564
1565 }
1566
1567 /* Add a found vars into available variables list */
1568 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1569 {
1570         struct available_var_finder *af =
1571                         container_of(pf, struct available_var_finder, pf);
1572         struct perf_probe_point *pp = &pf->pev->point;
1573         struct variable_list *vl;
1574         Dwarf_Die die_mem;
1575         int ret;
1576
1577         /*
1578          * For some reason (e.g. different column assigned to same address),
1579          * this callback can be called with the address which already passed.
1580          * Ignore it first.
1581          */
1582         if (available_var_finder_overlap(af))
1583                 return 0;
1584
1585         /* Check number of tevs */
1586         if (af->nvls == af->max_vls) {
1587                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1588                 return -ERANGE;
1589         }
1590         vl = &af->vls[af->nvls++];
1591
1592         /* Trace point should be converted from subprogram DIE */
1593         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1594                                      pp->retprobe, pp->function, &vl->point);
1595         if (ret < 0)
1596                 return ret;
1597
1598         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1599                  vl->point.offset);
1600
1601         /* Find local variables */
1602         vl->vars = strlist__new(NULL, NULL);
1603         if (vl->vars == NULL)
1604                 return -ENOMEM;
1605         af->child = true;
1606         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1607
1608         /* Find external variables */
1609         if (!probe_conf.show_ext_vars)
1610                 goto out;
1611         /* Don't need to search child DIE for external vars. */
1612         af->child = false;
1613         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1614
1615 out:
1616         if (strlist__empty(vl->vars)) {
1617                 strlist__delete(vl->vars);
1618                 vl->vars = NULL;
1619         }
1620
1621         return ret;
1622 }
1623
1624 /*
1625  * Find available variables at given probe point
1626  * Return the number of found probe points. Return 0 if there is no
1627  * matched probe point. Return <0 if an error occurs.
1628  */
1629 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1630                                       struct perf_probe_event *pev,
1631                                       struct variable_list **vls)
1632 {
1633         struct available_var_finder af = {
1634                         .pf = {.pev = pev, .dbg = dbg, .callback = add_available_vars},
1635                         .mod = dbg->mod,
1636                         .max_vls = probe_conf.max_probes};
1637         int ret;
1638
1639         /* Allocate result vls array */
1640         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1641         if (*vls == NULL)
1642                 return -ENOMEM;
1643
1644         af.vls = *vls;
1645         af.nvls = 0;
1646
1647         ret = debuginfo__find_probes(dbg, &af.pf);
1648         if (ret < 0) {
1649                 /* Free vlist for error */
1650                 while (af.nvls--) {
1651                         zfree(&af.vls[af.nvls].point.symbol);
1652                         strlist__delete(af.vls[af.nvls].vars);
1653                 }
1654                 zfree(vls);
1655                 return ret;
1656         }
1657
1658         return (ret < 0) ? ret : af.nvls;
1659 }
1660
1661 /* For the kernel module, we need a special code to get a DIE */
1662 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1663                                 bool adjust_offset)
1664 {
1665         int n, i;
1666         Elf32_Word shndx;
1667         Elf_Scn *scn;
1668         Elf *elf;
1669         GElf_Shdr mem, *shdr;
1670         const char *p;
1671
1672         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1673         if (!elf)
1674                 return -EINVAL;
1675
1676         /* Get the number of relocations */
1677         n = dwfl_module_relocations(dbg->mod);
1678         if (n < 0)
1679                 return -ENOENT;
1680         /* Search the relocation related .text section */
1681         for (i = 0; i < n; i++) {
1682                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1683                 if (strcmp(p, ".text") == 0) {
1684                         /* OK, get the section header */
1685                         scn = elf_getscn(elf, shndx);
1686                         if (!scn)
1687                                 return -ENOENT;
1688                         shdr = gelf_getshdr(scn, &mem);
1689                         if (!shdr)
1690                                 return -ENOENT;
1691                         *offs = shdr->sh_addr;
1692                         if (adjust_offset)
1693                                 *offs -= shdr->sh_offset;
1694                 }
1695         }
1696         return 0;
1697 }
1698
1699 /* Reverse search */
1700 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1701                                 struct perf_probe_point *ppt)
1702 {
1703         Dwarf_Die cudie, spdie, indie;
1704         Dwarf_Addr _addr = 0, baseaddr = 0;
1705         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1706         int baseline = 0, lineno = 0, ret = 0;
1707
1708         /* We always need to relocate the address for aranges */
1709         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1710                 addr += baseaddr;
1711         /* Find cu die */
1712         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1713                 pr_warning("Failed to find debug information for address %lx\n",
1714                            addr);
1715                 ret = -EINVAL;
1716                 goto end;
1717         }
1718
1719         /* Find a corresponding line (filename and lineno) */
1720         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1721         /* Don't care whether it failed or not */
1722
1723         /* Find a corresponding function (name, baseline and baseaddr) */
1724         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1725                 /* Get function entry information */
1726                 func = basefunc = dwarf_diename(&spdie);
1727                 if (!func ||
1728                     die_entrypc(&spdie, &baseaddr) != 0 ||
1729                     dwarf_decl_line(&spdie, &baseline) != 0) {
1730                         lineno = 0;
1731                         goto post;
1732                 }
1733
1734                 fname = dwarf_decl_file(&spdie);
1735                 if (addr == (unsigned long)baseaddr) {
1736                         /* Function entry - Relative line number is 0 */
1737                         lineno = baseline;
1738                         goto post;
1739                 }
1740
1741                 /* Track down the inline functions step by step */
1742                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1743                                                 &indie)) {
1744                         /* There is an inline function */
1745                         if (die_entrypc(&indie, &_addr) == 0 &&
1746                             _addr == addr) {
1747                                 /*
1748                                  * addr is at an inline function entry.
1749                                  * In this case, lineno should be the call-site
1750                                  * line number. (overwrite lineinfo)
1751                                  */
1752                                 lineno = die_get_call_lineno(&indie);
1753                                 fname = die_get_call_file(&indie);
1754                                 break;
1755                         } else {
1756                                 /*
1757                                  * addr is in an inline function body.
1758                                  * Since lineno points one of the lines
1759                                  * of the inline function, baseline should
1760                                  * be the entry line of the inline function.
1761                                  */
1762                                 tmp = dwarf_diename(&indie);
1763                                 if (!tmp ||
1764                                     dwarf_decl_line(&indie, &baseline) != 0)
1765                                         break;
1766                                 func = tmp;
1767                                 spdie = indie;
1768                         }
1769                 }
1770                 /* Verify the lineno and baseline are in a same file */
1771                 tmp = dwarf_decl_file(&spdie);
1772                 if (!tmp || strcmp(tmp, fname) != 0)
1773                         lineno = 0;
1774         }
1775
1776 post:
1777         /* Make a relative line number or an offset */
1778         if (lineno)
1779                 ppt->line = lineno - baseline;
1780         else if (basefunc) {
1781                 ppt->offset = addr - (unsigned long)baseaddr;
1782                 func = basefunc;
1783         }
1784
1785         /* Duplicate strings */
1786         if (func) {
1787                 ppt->function = strdup(func);
1788                 if (ppt->function == NULL) {
1789                         ret = -ENOMEM;
1790                         goto end;
1791                 }
1792         }
1793         if (fname) {
1794                 ppt->file = strdup(fname);
1795                 if (ppt->file == NULL) {
1796                         zfree(&ppt->function);
1797                         ret = -ENOMEM;
1798                         goto end;
1799                 }
1800         }
1801 end:
1802         if (ret == 0 && (fname || func))
1803                 ret = 1;        /* Found a point */
1804         return ret;
1805 }
1806
1807 /* Add a line and store the src path */
1808 static int line_range_add_line(const char *src, unsigned int lineno,
1809                                struct line_range *lr)
1810 {
1811         /* Copy source path */
1812         if (!lr->path) {
1813                 lr->path = strdup(src);
1814                 if (lr->path == NULL)
1815                         return -ENOMEM;
1816         }
1817         return intlist__add(lr->line_list, lineno);
1818 }
1819
1820 static int line_range_walk_cb(const char *fname, int lineno,
1821                               Dwarf_Addr addr __maybe_unused,
1822                               void *data)
1823 {
1824         struct line_finder *lf = data;
1825         const char *__fname;
1826         int __lineno;
1827         int err;
1828
1829         if ((strtailcmp(fname, lf->fname) != 0) ||
1830             (lf->lno_s > lineno || lf->lno_e < lineno))
1831                 return 0;
1832
1833         /* Make sure this line can be reversable */
1834         if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
1835             && (lineno != __lineno || strcmp(fname, __fname)))
1836                 return 0;
1837
1838         err = line_range_add_line(fname, lineno, lf->lr);
1839         if (err < 0 && err != -EEXIST)
1840                 return err;
1841
1842         return 0;
1843 }
1844
1845 /* Find line range from its line number */
1846 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1847 {
1848         int ret;
1849
1850         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1851
1852         /* Update status */
1853         if (ret >= 0)
1854                 if (!intlist__empty(lf->lr->line_list))
1855                         ret = lf->found = 1;
1856                 else
1857                         ret = 0;        /* Lines are not found */
1858         else {
1859                 zfree(&lf->lr->path);
1860         }
1861         return ret;
1862 }
1863
1864 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1865 {
1866         int ret = find_line_range_by_line(in_die, data);
1867
1868         /*
1869          * We have to check all instances of inlined function, because
1870          * some execution paths can be optimized out depends on the
1871          * function argument of instances. However, if an error occurs,
1872          * it should be handled by the caller.
1873          */
1874         return ret < 0 ? ret : 0;
1875 }
1876
1877 /* Search function definition from function name */
1878 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1879 {
1880         struct dwarf_callback_param *param = data;
1881         struct line_finder *lf = param->data;
1882         struct line_range *lr = lf->lr;
1883
1884         /* Check declared file */
1885         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1886                 return DWARF_CB_OK;
1887
1888         if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
1889                 lf->fname = dwarf_decl_file(sp_die);
1890                 dwarf_decl_line(sp_die, &lr->offset);
1891                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1892                 lf->lno_s = lr->offset + lr->start;
1893                 if (lf->lno_s < 0)      /* Overflow */
1894                         lf->lno_s = INT_MAX;
1895                 lf->lno_e = lr->offset + lr->end;
1896                 if (lf->lno_e < 0)      /* Overflow */
1897                         lf->lno_e = INT_MAX;
1898                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1899                 lr->start = lf->lno_s;
1900                 lr->end = lf->lno_e;
1901                 if (!die_is_func_instance(sp_die))
1902                         param->retval = die_walk_instances(sp_die,
1903                                                 line_range_inline_cb, lf);
1904                 else
1905                         param->retval = find_line_range_by_line(sp_die, lf);
1906                 return DWARF_CB_ABORT;
1907         }
1908         return DWARF_CB_OK;
1909 }
1910
1911 static int find_line_range_by_func(struct line_finder *lf)
1912 {
1913         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1914         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1915         return param.retval;
1916 }
1917
1918 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1919 {
1920         struct line_finder lf = {.lr = lr, .found = 0};
1921         int ret = 0;
1922         Dwarf_Off off = 0, noff;
1923         size_t cuhl;
1924         Dwarf_Die *diep;
1925         const char *comp_dir;
1926
1927         /* Fastpath: lookup by function name from .debug_pubnames section */
1928         if (lr->function) {
1929                 struct pubname_callback_param pubname_param = {
1930                         .function = lr->function, .file = lr->file,
1931                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1932                 struct dwarf_callback_param line_range_param = {
1933                         .data = (void *)&lf, .retval = 0};
1934
1935                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1936                                   &pubname_param, 0);
1937                 if (pubname_param.found) {
1938                         line_range_search_cb(&lf.sp_die, &line_range_param);
1939                         if (lf.found)
1940                                 goto found;
1941                 }
1942         }
1943
1944         /* Loop on CUs (Compilation Unit) */
1945         while (!lf.found && ret >= 0) {
1946                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1947                                  NULL, NULL, NULL) != 0)
1948                         break;
1949
1950                 /* Get the DIE(Debugging Information Entry) of this CU */
1951                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1952                 if (!diep)
1953                         continue;
1954
1955                 /* Check if target file is included. */
1956                 if (lr->file)
1957                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1958                 else
1959                         lf.fname = 0;
1960
1961                 if (!lr->file || lf.fname) {
1962                         if (lr->function)
1963                                 ret = find_line_range_by_func(&lf);
1964                         else {
1965                                 lf.lno_s = lr->start;
1966                                 lf.lno_e = lr->end;
1967                                 ret = find_line_range_by_line(NULL, &lf);
1968                         }
1969                 }
1970                 off = noff;
1971         }
1972
1973 found:
1974         /* Store comp_dir */
1975         if (lf.found) {
1976                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1977                 if (comp_dir) {
1978                         lr->comp_dir = strdup(comp_dir);
1979                         if (!lr->comp_dir)
1980                                 ret = -ENOMEM;
1981                 }
1982         }
1983
1984         pr_debug("path: %s\n", lr->path);
1985         return (ret < 0) ? ret : lf.found;
1986 }
1987
1988 #ifdef HAVE_DEBUGINFOD_SUPPORT
1989 /* debuginfod doesn't require the comp_dir but buildid is required */
1990 static int get_source_from_debuginfod(const char *raw_path,
1991                                 const char *sbuild_id, char **new_path)
1992 {
1993         debuginfod_client *c = debuginfod_begin();
1994         const char *p = raw_path;
1995         int fd;
1996
1997         if (!c)
1998                 return -ENOMEM;
1999
2000         fd = debuginfod_find_source(c, (const unsigned char *)sbuild_id,
2001                                 0, p, new_path);
2002         pr_debug("Search %s from debuginfod -> %d\n", p, fd);
2003         if (fd >= 0)
2004                 close(fd);
2005         debuginfod_end(c);
2006         if (fd < 0) {
2007                 pr_debug("Failed to find %s in debuginfod (%s)\n",
2008                         raw_path, sbuild_id);
2009                 return -ENOENT;
2010         }
2011         pr_debug("Got a source %s\n", *new_path);
2012
2013         return 0;
2014 }
2015 #else
2016 static inline int get_source_from_debuginfod(const char *raw_path __maybe_unused,
2017                                 const char *sbuild_id __maybe_unused,
2018                                 char **new_path __maybe_unused)
2019 {
2020         return -ENOTSUP;
2021 }
2022 #endif
2023 /*
2024  * Find a src file from a DWARF tag path. Prepend optional source path prefix
2025  * and chop off leading directories that do not exist. Result is passed back as
2026  * a newly allocated path on success.
2027  * Return 0 if file was found and readable, -errno otherwise.
2028  */
2029 int find_source_path(const char *raw_path, const char *sbuild_id,
2030                 const char *comp_dir, char **new_path)
2031 {
2032         const char *prefix = symbol_conf.source_prefix;
2033
2034         if (sbuild_id && !prefix) {
2035                 if (!get_source_from_debuginfod(raw_path, sbuild_id, new_path))
2036                         return 0;
2037         }
2038
2039         if (!prefix) {
2040                 if (raw_path[0] != '/' && comp_dir)
2041                         /* If not an absolute path, try to use comp_dir */
2042                         prefix = comp_dir;
2043                 else {
2044                         if (access(raw_path, R_OK) == 0) {
2045                                 *new_path = strdup(raw_path);
2046                                 return *new_path ? 0 : -ENOMEM;
2047                         } else
2048                                 return -errno;
2049                 }
2050         }
2051
2052         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
2053         if (!*new_path)
2054                 return -ENOMEM;
2055
2056         for (;;) {
2057                 sprintf(*new_path, "%s/%s", prefix, raw_path);
2058
2059                 if (access(*new_path, R_OK) == 0)
2060                         return 0;
2061
2062                 if (!symbol_conf.source_prefix) {
2063                         /* In case of searching comp_dir, don't retry */
2064                         zfree(new_path);
2065                         return -errno;
2066                 }
2067
2068                 switch (errno) {
2069                 case ENAMETOOLONG:
2070                 case ENOENT:
2071                 case EROFS:
2072                 case EFAULT:
2073                         raw_path = strchr(++raw_path, '/');
2074                         if (!raw_path) {
2075                                 zfree(new_path);
2076                                 return -ENOENT;
2077                         }
2078                         continue;
2079
2080                 default:
2081                         zfree(new_path);
2082                         return -errno;
2083                 }
2084         }
2085 }