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 "strlist.h"
  28 #include "symbol.h"
  29 #include "probe-finder.h"
  30 #include "probe-file.h"
  31 #include "string2.h"
  32
  33 /* Kprobe tracer basic type is up to u64 */
  34 #define MAX_BASIC_TYPE_BITS     64
  35
  36 /* Dwarf FL wrappers */
  37 static char *debuginfo_path;    /* Currently dummy */
  38
  39 static const Dwfl_Callbacks offline_callbacks = {
  40         .find_debuginfo = dwfl_standard_find_debuginfo,
  41         .debuginfo_path = &debuginfo_path,
  42
  43         .section_address = dwfl_offline_section_address,
  44
  45         /* We use this table for core files too.  */
  46         .find_elf = dwfl_build_id_find_elf,
  47 };
  48
  49 /* Get a Dwarf from offline image */
  50 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  51                                          const char *path)
  52 {
  53         int fd;
  54
  55         fd = open(path, O_RDONLY);
  56         if (fd < 0)
  57                 return fd;
  58
  59         dbg->dwfl = dwfl_begin(&offline_callbacks);
  60         if (!dbg->dwfl)
  61                 goto error;
  62
  63         dwfl_report_begin(dbg->dwfl);
  64         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  65         if (!dbg->mod)
  66                 goto error;
  67
  68         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  69         if (!dbg->dbg)
  70                 goto error;
  71
  72         dwfl_report_end(dbg->dwfl, NULL, NULL);
  73
  74         return 0;
  75 error:
  76         if (dbg->dwfl)
  77                 dwfl_end(dbg->dwfl);
  78         else
  79                 close(fd);
  80         memset(dbg, 0, sizeof(*dbg));
  81
  82         return -ENOENT;
  83 }
  84
  85 static struct debuginfo *__debuginfo__new(const char *path)
  86 {
  87         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  88         if (!dbg)
  89                 return NULL;
  90
  91         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  92                 zfree(&dbg);
  93         if (dbg)
  94                 pr_debug("Open Debuginfo file: %s\n", path);
  95         return dbg;
  96 }
  97
  98 enum dso_binary_type distro_dwarf_types[] = {
  99         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 100         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 101         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 102         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 103         DSO_BINARY_TYPE__NOT_FOUND,
 104 };
 105
 106 struct debuginfo *debuginfo__new(const char *path)
 107 {
 108         enum dso_binary_type *type;
 109         char buf[PATH_MAX], nil = '\0';
 110         struct dso *dso;
 111         struct debuginfo *dinfo = NULL;
 112
 113         /* Try to open distro debuginfo files */
 114         dso = dso__new(path);
 115         if (!dso)
 116                 goto out;
 117
 118         for (type = distro_dwarf_types;
 119              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 120              type++) {
 121                 if (dso__read_binary_type_filename(dso, *type, &nil,
 122                                                    buf, PATH_MAX) < 0)
 123                         continue;
 124                 dinfo = __debuginfo__new(buf);
 125         }
 126         dso__put(dso);
 127
 128 out:
 129         /* if failed to open all distro debuginfo, open given binary */
 130         return dinfo ? : __debuginfo__new(path);
 131 }
 132
 133 void debuginfo__delete(struct debuginfo *dbg)
 134 {
 135         if (dbg) {
 136                 if (dbg->dwfl)
 137                         dwfl_end(dbg->dwfl);
 138                 free(dbg);
 139         }
 140 }
 141
 142 /*
 143  * Probe finder related functions
 144  */
 145
 146 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 147 {
 148         struct probe_trace_arg_ref *ref;
 149         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 150         if (ref != NULL)
 151                 ref->offset = offs;
 152         return ref;
 153 }
 154
 155 /*
 156  * Convert a location into trace_arg.
 157  * If tvar == NULL, this just checks variable can be converted.
 158  * If fentry == true and vr_die is a parameter, do huristic search
 159  * for the location fuzzed by function entry mcount.
 160  */
 161 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 162                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 163                                      unsigned int machine,
 164                                      struct probe_trace_arg *tvar)
 165 {
 166         Dwarf_Attribute attr;
 167         Dwarf_Addr tmp = 0;
 168         Dwarf_Op *op;
 169         size_t nops;
 170         unsigned int regn;
 171         Dwarf_Word offs = 0;
 172         bool ref = false;
 173         const char *regs;
 174         int ret, ret2 = 0;
 175
 176         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 177                 goto static_var;
 178
 179         /* TODO: handle more than 1 exprs */
 180         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 181                 return -EINVAL; /* Broken DIE ? */
 182         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 183                 ret = dwarf_entrypc(sp_die, &tmp);
 184                 if (ret)
 185                         return -ENOENT;
 186
 187                 if (probe_conf.show_location_range &&
 188                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 189                         ret2 = -ERANGE;
 190                 } else if (addr != tmp ||
 191                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 192                         return -ENOENT;
 193                 }
 194
 195                 ret = dwarf_highpc(sp_die, &tmp);
 196                 if (ret)
 197                         return -ENOENT;
 198                 /*
 199                  * This is fuzzed by fentry mcount. We try to find the
 200                  * parameter location at the earliest address.
 201                  */
 202                 for (addr += 1; addr <= tmp; addr++) {
 203                         if (dwarf_getlocation_addr(&attr, addr, &op,
 204                                                    &nops, 1) > 0)
 205                                 goto found;
 206                 }
 207                 return -ENOENT;
 208         }
 209 found:
 210         if (nops == 0)
 211                 /* TODO: Support const_value */
 212                 return -ENOENT;
 213
 214         if (op->atom == DW_OP_addr) {
 215 static_var:
 216                 if (!tvar)
 217                         return ret2;
 218                 /* Static variables on memory (not stack), make @varname */
 219                 ret = strlen(dwarf_diename(vr_die));
 220                 tvar->value = zalloc(ret + 2);
 221                 if (tvar->value == NULL)
 222                         return -ENOMEM;
 223                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 224                 tvar->ref = alloc_trace_arg_ref((long)offs);
 225                 if (tvar->ref == NULL)
 226                         return -ENOMEM;
 227                 return ret2;
 228         }
 229
 230         /* If this is based on frame buffer, set the offset */
 231         if (op->atom == DW_OP_fbreg) {
 232                 if (fb_ops == NULL)
 233                         return -ENOTSUP;
 234                 ref = true;
 235                 offs = op->number;
 236                 op = &fb_ops[0];
 237         }
 238
 239         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 240                 regn = op->atom - DW_OP_breg0;
 241                 offs += op->number;
 242                 ref = true;
 243         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 244                 regn = op->atom - DW_OP_reg0;
 245         } else if (op->atom == DW_OP_bregx) {
 246                 regn = op->number;
 247                 offs += op->number2;
 248                 ref = true;
 249         } else if (op->atom == DW_OP_regx) {
 250                 regn = op->number;
 251         } else {
 252                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 253                 return -ENOTSUP;
 254         }
 255
 256         if (!tvar)
 257                 return ret2;
 258
 259         regs = get_dwarf_regstr(regn, machine);
 260         if (!regs) {
 261                 /* This should be a bug in DWARF or this tool */
 262                 pr_warning("Mapping for the register number %u "
 263                            "missing on this architecture.\n", regn);
 264                 return -ENOTSUP;
 265         }
 266
 267         tvar->value = strdup(regs);
 268         if (tvar->value == NULL)
 269                 return -ENOMEM;
 270
 271         if (ref) {
 272                 tvar->ref = alloc_trace_arg_ref((long)offs);
 273                 if (tvar->ref == NULL)
 274                         return -ENOMEM;
 275         }
 276         return ret2;
 277 }
 278
 279 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 280
 281 static int convert_variable_type(Dwarf_Die *vr_die,
 282                                  struct probe_trace_arg *tvar,
 283                                  const char *cast, bool user_access)
 284 {
 285         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 286         Dwarf_Die type;
 287         char buf[16];
 288         char sbuf[STRERR_BUFSIZE];
 289         int bsize, boffs, total;
 290         int ret;
 291         char prefix;
 292
 293         /* TODO: check all types */
 294         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 295             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 296                 /* Non string type is OK */
 297                 /* and respect signedness/hexadecimal cast */
 298                 tvar->type = strdup(cast);
 299                 return (tvar->type == NULL) ? -ENOMEM : 0;
 300         }
 301
 302         bsize = dwarf_bitsize(vr_die);
 303         if (bsize > 0) {
 304                 /* This is a bitfield */
 305                 boffs = dwarf_bitoffset(vr_die);
 306                 total = dwarf_bytesize(vr_die);
 307                 if (boffs < 0 || total < 0)
 308                         return -ENOENT;
 309                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 310                                 BYTES_TO_BITS(total));
 311                 goto formatted;
 312         }
 313
 314         if (die_get_real_type(vr_die, &type) == NULL) {
 315                 pr_warning("Failed to get a type information of %s.\n",
 316                            dwarf_diename(vr_die));
 317                 return -ENOENT;
 318         }
 319
 320         pr_debug("%s type is %s.\n",
 321                  dwarf_diename(vr_die), dwarf_diename(&type));
 322
 323         if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
 324                 /* String type */
 325                 ret = dwarf_tag(&type);
 326                 if (ret != DW_TAG_pointer_type &&
 327                     ret != DW_TAG_array_type) {
 328                         pr_warning("Failed to cast into string: "
 329                                    "%s(%s) is not a pointer nor array.\n",
 330                                    dwarf_diename(vr_die), dwarf_diename(&type));
 331                         return -EINVAL;
 332                 }
 333                 if (die_get_real_type(&type, &type) == NULL) {
 334                         pr_warning("Failed to get a type"
 335                                    " information.\n");
 336                         return -ENOENT;
 337                 }
 338                 if (ret == DW_TAG_pointer_type) {
 339                         while (*ref_ptr)
 340                                 ref_ptr = &(*ref_ptr)->next;
 341                         /* Add new reference with offset +0 */
 342                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 343                         if (*ref_ptr == NULL) {
 344                                 pr_warning("Out of memory error\n");
 345                                 return -ENOMEM;
 346                         }
 347                         (*ref_ptr)->user_access = user_access;
 348                 }
 349                 if (!die_compare_name(&type, "char") &&
 350                     !die_compare_name(&type, "unsigned char")) {
 351                         pr_warning("Failed to cast into string: "
 352                                    "%s is not (unsigned) char *.\n",
 353                                    dwarf_diename(vr_die));
 354                         return -EINVAL;
 355                 }
 356                 tvar->type = strdup(cast);
 357                 return (tvar->type == NULL) ? -ENOMEM : 0;
 358         }
 359
 360         if (cast && (strcmp(cast, "u") == 0))
 361                 prefix = 'u';
 362         else if (cast && (strcmp(cast, "s") == 0))
 363                 prefix = 's';
 364         else if (cast && (strcmp(cast, "x") == 0) &&
 365                  probe_type_is_available(PROBE_TYPE_X))
 366                 prefix = 'x';
 367         else
 368                 prefix = die_is_signed_type(&type) ? 's' :
 369                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 370
 371         ret = dwarf_bytesize(&type);
 372         if (ret <= 0)
 373                 /* No size ... try to use default type */
 374                 return 0;
 375         ret = BYTES_TO_BITS(ret);
 376
 377         /* Check the bitwidth */
 378         if (ret > MAX_BASIC_TYPE_BITS) {
 379                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 380                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 381                 ret = MAX_BASIC_TYPE_BITS;
 382         }
 383         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 384
 385 formatted:
 386         if (ret < 0 || ret >= 16) {
 387                 if (ret >= 16)
 388                         ret = -E2BIG;
 389                 pr_warning("Failed to convert variable type: %s\n",
 390                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 391                 return ret;
 392         }
 393         tvar->type = strdup(buf);
 394         if (tvar->type == NULL)
 395                 return -ENOMEM;
 396         return 0;
 397 }
 398
 399 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 400                                     struct perf_probe_arg_field *field,
 401                                     struct probe_trace_arg_ref **ref_ptr,
 402                                     Dwarf_Die *die_mem, bool user_access)
 403 {
 404         struct probe_trace_arg_ref *ref = *ref_ptr;
 405         Dwarf_Die type;
 406         Dwarf_Word offs;
 407         int ret, tag;
 408
 409         pr_debug("converting %s in %s\n", field->name, varname);
 410         if (die_get_real_type(vr_die, &type) == NULL) {
 411                 pr_warning("Failed to get the type of %s.\n", varname);
 412                 return -ENOENT;
 413         }
 414         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 415                   (unsigned)dwarf_dieoffset(&type));
 416         tag = dwarf_tag(&type);
 417
 418         if (field->name[0] == '[' &&
 419             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 420                 /* Save original type for next field or type */
 421                 memcpy(die_mem, &type, sizeof(*die_mem));
 422                 /* Get the type of this array */
 423                 if (die_get_real_type(&type, &type) == NULL) {
 424                         pr_warning("Failed to get the type of %s.\n", varname);
 425                         return -ENOENT;
 426                 }
 427                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 428                          (unsigned)dwarf_dieoffset(&type));
 429                 if (tag == DW_TAG_pointer_type) {
 430                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 431                         if (ref == NULL)
 432                                 return -ENOMEM;
 433                         if (*ref_ptr)
 434                                 (*ref_ptr)->next = ref;
 435                         else
 436                                 *ref_ptr = ref;
 437                 }
 438                 ref->offset += dwarf_bytesize(&type) * field->index;
 439                 ref->user_access = user_access;
 440                 goto next;
 441         } else if (tag == DW_TAG_pointer_type) {
 442                 /* Check the pointer and dereference */
 443                 if (!field->ref) {
 444                         pr_err("Semantic error: %s must be referred by '->'\n",
 445                                field->name);
 446                         return -EINVAL;
 447                 }
 448                 /* Get the type pointed by this pointer */
 449                 if (die_get_real_type(&type, &type) == NULL) {
 450                         pr_warning("Failed to get the type of %s.\n", varname);
 451                         return -ENOENT;
 452                 }
 453                 /* Verify it is a data structure  */
 454                 tag = dwarf_tag(&type);
 455                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 456                         pr_warning("%s is not a data structure nor a union.\n",
 457                                    varname);
 458                         return -EINVAL;
 459                 }
 460
 461                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 462                 if (ref == NULL)
 463                         return -ENOMEM;
 464                 if (*ref_ptr)
 465                         (*ref_ptr)->next = ref;
 466                 else
 467                         *ref_ptr = ref;
 468         } else {
 469                 /* Verify it is a data structure  */
 470                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 471                         pr_warning("%s is not a data structure nor a union.\n",
 472                                    varname);
 473                         return -EINVAL;
 474                 }
 475                 if (field->name[0] == '[') {
 476                         pr_err("Semantic error: %s is not a pointer"
 477                                " nor array.\n", varname);
 478                         return -EINVAL;
 479                 }
 480                 /* While prcessing unnamed field, we don't care about this */
 481                 if (field->ref && dwarf_diename(vr_die)) {
 482                         pr_err("Semantic error: %s must be referred by '.'\n",
 483                                field->name);
 484                         return -EINVAL;
 485                 }
 486                 if (!ref) {
 487                         pr_warning("Structure on a register is not "
 488                                    "supported yet.\n");
 489                         return -ENOTSUP;
 490                 }
 491         }
 492
 493         if (die_find_member(&type, field->name, die_mem) == NULL) {
 494                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 495                            dwarf_diename(&type), field->name);
 496                 return -EINVAL;
 497         }
 498
 499         /* Get the offset of the field */
 500         if (tag == DW_TAG_union_type) {
 501                 offs = 0;
 502         } else {
 503                 ret = die_get_data_member_location(die_mem, &offs);
 504                 if (ret < 0) {
 505                         pr_warning("Failed to get the offset of %s.\n",
 506                                    field->name);
 507                         return ret;
 508                 }
 509         }
 510         ref->offset += (long)offs;
 511         ref->user_access = user_access;
 512
 513         /* If this member is unnamed, we need to reuse this field */
 514         if (!dwarf_diename(die_mem))
 515                 return convert_variable_fields(die_mem, varname, field,
 516                                                 &ref, die_mem, user_access);
 517
 518 next:
 519         /* Converting next field */
 520         if (field->next)
 521                 return convert_variable_fields(die_mem, field->name,
 522                                 field->next, &ref, die_mem, user_access);
 523         else
 524                 return 0;
 525 }
 526
 527 /* Show a variables in kprobe event format */
 528 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 529 {
 530         Dwarf_Die die_mem;
 531         int ret;
 532
 533         pr_debug("Converting variable %s into trace event.\n",
 534                  dwarf_diename(vr_die));
 535
 536         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 537                                         &pf->sp_die, pf->machine, pf->tvar);
 538         if (ret == -ENOENT || ret == -EINVAL) {
 539                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 540                        " Perhaps it has been optimized out.\n"
 541                        " Use -V with the --range option to show '%s' location range.\n",
 542                        pf->pvar->var, pf->pvar->var);
 543         } else if (ret == -ENOTSUP)
 544                 pr_err("Sorry, we don't support this variable location yet.\n");
 545         else if (ret == 0 && pf->pvar->field) {
 546                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 547                                               pf->pvar->field, &pf->tvar->ref,
 548                                               &die_mem, pf->pvar->user_access);
 549                 vr_die = &die_mem;
 550         }
 551         if (ret == 0)
 552                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
 553                                             pf->pvar->user_access);
 554         /* *expr will be cached in libdw. Don't free it. */
 555         return ret;
 556 }
 557
 558 /* Find a variable in a scope DIE */
 559 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 560 {
 561         Dwarf_Die vr_die;
 562         char *buf, *ptr;
 563         int ret = 0;
 564
 565         /* Copy raw parameters */
 566         if (!is_c_varname(pf->pvar->var))
 567                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 568
 569         if (pf->pvar->name)
 570                 pf->tvar->name = strdup(pf->pvar->name);
 571         else {
 572                 buf = synthesize_perf_probe_arg(pf->pvar);
 573                 if (!buf)
 574                         return -ENOMEM;
 575                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 576                 if (ptr)
 577                         *ptr = '_';
 578                 pf->tvar->name = buf;
 579         }
 580         if (pf->tvar->name == NULL)
 581                 return -ENOMEM;
 582
 583         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 584         /* Search child die for local variables and parameters. */
 585         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 586                 /* Search again in global variables */
 587                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 588                                                 0, &vr_die)) {
 589                         pr_warning("Failed to find '%s' in this function.\n",
 590                                    pf->pvar->var);
 591                         ret = -ENOENT;
 592                 }
 593         }
 594         if (ret >= 0)
 595                 ret = convert_variable(&vr_die, pf);
 596
 597         return ret;
 598 }
 599
 600 /* Convert subprogram DIE to trace point */
 601 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 602                                   Dwarf_Addr paddr, bool retprobe,
 603                                   const char *function,
 604                                   struct probe_trace_point *tp)
 605 {
 606         Dwarf_Addr eaddr, highaddr;
 607         GElf_Sym sym;
 608         const char *symbol;
 609
 610         /* Verify the address is correct */
 611         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 612                 pr_warning("Failed to get entry address of %s\n",
 613                            dwarf_diename(sp_die));
 614                 return -ENOENT;
 615         }
 616         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 617                 pr_warning("Failed to get end address of %s\n",
 618                            dwarf_diename(sp_die));
 619                 return -ENOENT;
 620         }
 621         if (paddr > highaddr) {
 622                 pr_warning("Offset specified is greater than size of %s\n",
 623                            dwarf_diename(sp_die));
 624                 return -EINVAL;
 625         }
 626
 627         symbol = dwarf_diename(sp_die);
 628         if (!symbol) {
 629                 /* Try to get the symbol name from symtab */
 630                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 631                 if (!symbol) {
 632                         pr_warning("Failed to find symbol at 0x%lx\n",
 633                                    (unsigned long)paddr);
 634                         return -ENOENT;
 635                 }
 636                 eaddr = sym.st_value;
 637         }
 638         tp->offset = (unsigned long)(paddr - eaddr);
 639         tp->address = (unsigned long)paddr;
 640         tp->symbol = strdup(symbol);
 641         if (!tp->symbol)
 642                 return -ENOMEM;
 643
 644         /* Return probe must be on the head of a subprogram */
 645         if (retprobe) {
 646                 if (eaddr != paddr) {
 647                         pr_warning("Failed to find \"%s%%return\",\n"
 648                                    " because %s is an inlined function and"
 649                                    " has no return point.\n", function,
 650                                    function);
 651                         return -EINVAL;
 652                 }
 653                 tp->retprobe = true;
 654         }
 655
 656         return 0;
 657 }
 658
 659 /* Call probe_finder callback with scope DIE */
 660 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 661 {
 662         Dwarf_Attribute fb_attr;
 663         Dwarf_Frame *frame = NULL;
 664         size_t nops;
 665         int ret;
 666
 667         if (!sc_die) {
 668                 pr_err("Caller must pass a scope DIE. Program error.\n");
 669                 return -EINVAL;
 670         }
 671
 672         /* If not a real subprogram, find a real one */
 673         if (!die_is_func_def(sc_die)) {
 674                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 675                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 676                                 pr_warning("Ignoring tail call from %s\n",
 677                                                 dwarf_diename(&pf->sp_die));
 678                                 return 0;
 679                         } else {
 680                                 pr_warning("Failed to find probe point in any "
 681                                            "functions.\n");
 682                                 return -ENOENT;
 683                         }
 684                 }
 685         } else
 686                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 687
 688         /* Get the frame base attribute/ops from subprogram */
 689         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 690         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 691         if (ret <= 0 || nops == 0) {
 692                 pf->fb_ops = NULL;
 693 #if _ELFUTILS_PREREQ(0, 142)
 694         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 695                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 696                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 697                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 698                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 699                         pr_warning("Failed to get call frame on 0x%jx\n",
 700                                    (uintmax_t)pf->addr);
 701                         free(frame);
 702                         return -ENOENT;
 703                 }
 704 #endif
 705         }
 706
 707         /* Call finder's callback handler */
 708         ret = pf->callback(sc_die, pf);
 709
 710         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 711         free(frame);
 712         pf->fb_ops = NULL;
 713
 714         return ret;
 715 }
 716
 717 struct find_scope_param {
 718         const char *function;
 719         const char *file;
 720         int line;
 721         int diff;
 722         Dwarf_Die *die_mem;
 723         bool found;
 724 };
 725
 726 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 727 {
 728         struct find_scope_param *fsp = data;
 729         const char *file;
 730         int lno;
 731
 732         /* Skip if declared file name does not match */
 733         if (fsp->file) {
 734                 file = dwarf_decl_file(fn_die);
 735                 if (!file || strcmp(fsp->file, file) != 0)
 736                         return 0;
 737         }
 738         /* If the function name is given, that's what user expects */
 739         if (fsp->function) {
 740                 if (die_match_name(fn_die, fsp->function)) {
 741                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 742                         fsp->found = true;
 743                         return 1;
 744                 }
 745         } else {
 746                 /* With the line number, find the nearest declared DIE */
 747                 dwarf_decl_line(fn_die, &lno);
 748                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 749                         /* Keep a candidate and continue */
 750                         fsp->diff = fsp->line - lno;
 751                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 752                         fsp->found = true;
 753                 }
 754         }
 755         return 0;
 756 }
 757
 758 /* Find an appropriate scope fits to given conditions */
 759 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 760 {
 761         struct find_scope_param fsp = {
 762                 .function = pf->pev->point.function,
 763                 .file = pf->fname,
 764                 .line = pf->lno,
 765                 .diff = INT_MAX,
 766                 .die_mem = die_mem,
 767                 .found = false,
 768         };
 769
 770         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 771
 772         return fsp.found ? die_mem : NULL;
 773 }
 774
 775 static int probe_point_line_walker(const char *fname, int lineno,
 776                                    Dwarf_Addr addr, void *data)
 777 {
 778         struct probe_finder *pf = data;
 779         Dwarf_Die *sc_die, die_mem;
 780         int ret;
 781
 782         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 783                 return 0;
 784
 785         pf->addr = addr;
 786         sc_die = find_best_scope(pf, &die_mem);
 787         if (!sc_die) {
 788                 pr_warning("Failed to find scope of probe point.\n");
 789                 return -ENOENT;
 790         }
 791
 792         ret = call_probe_finder(sc_die, pf);
 793
 794         /* Continue if no error, because the line will be in inline function */
 795         return ret < 0 ? ret : 0;
 796 }
 797
 798 /* Find probe point from its line number */
 799 static int find_probe_point_by_line(struct probe_finder *pf)
 800 {
 801         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 802 }
 803
 804 /* Find lines which match lazy pattern */
 805 static int find_lazy_match_lines(struct intlist *list,
 806                                  const char *fname, const char *pat)
 807 {
 808         FILE *fp;
 809         char *line = NULL;
 810         size_t line_len;
 811         ssize_t len;
 812         int count = 0, linenum = 1;
 813         char sbuf[STRERR_BUFSIZE];
 814
 815         fp = fopen(fname, "r");
 816         if (!fp) {
 817                 pr_warning("Failed to open %s: %s\n", fname,
 818                            str_error_r(errno, sbuf, sizeof(sbuf)));
 819                 return -errno;
 820         }
 821
 822         while ((len = getline(&line, &line_len, fp)) > 0) {
 823
 824                 if (line[len - 1] == '\n')
 825                         line[len - 1] = '\0';
 826
 827                 if (strlazymatch(line, pat)) {
 828                         intlist__add(list, linenum);
 829                         count++;
 830                 }
 831                 linenum++;
 832         }
 833
 834         if (ferror(fp))
 835                 count = -errno;
 836         free(line);
 837         fclose(fp);
 838
 839         if (count == 0)
 840                 pr_debug("No matched lines found in %s.\n", fname);
 841         return count;
 842 }
 843
 844 static int probe_point_lazy_walker(const char *fname, int lineno,
 845                                    Dwarf_Addr addr, void *data)
 846 {
 847         struct probe_finder *pf = data;
 848         Dwarf_Die *sc_die, die_mem;
 849         int ret;
 850
 851         if (!intlist__has_entry(pf->lcache, lineno) ||
 852             strtailcmp(fname, pf->fname) != 0)
 853                 return 0;
 854
 855         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 856                  lineno, (unsigned long long)addr);
 857         pf->addr = addr;
 858         pf->lno = lineno;
 859         sc_die = find_best_scope(pf, &die_mem);
 860         if (!sc_die) {
 861                 pr_warning("Failed to find scope of probe point.\n");
 862                 return -ENOENT;
 863         }
 864
 865         ret = call_probe_finder(sc_die, pf);
 866
 867         /*
 868          * Continue if no error, because the lazy pattern will match
 869          * to other lines
 870          */
 871         return ret < 0 ? ret : 0;
 872 }
 873
 874 /* Find probe points from lazy pattern  */
 875 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 876 {
 877         int ret = 0;
 878         char *fpath;
 879
 880         if (intlist__empty(pf->lcache)) {
 881                 const char *comp_dir;
 882
 883                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 884                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 885                 if (ret < 0) {
 886                         pr_warning("Failed to find source file path.\n");
 887                         return ret;
 888                 }
 889
 890                 /* Matching lazy line pattern */
 891                 ret = find_lazy_match_lines(pf->lcache, fpath,
 892                                             pf->pev->point.lazy_line);
 893                 free(fpath);
 894                 if (ret <= 0)
 895                         return ret;
 896         }
 897
 898         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 899 }
 900
 901 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 902 {
 903         struct perf_probe_point *pp = &pf->pev->point;
 904
 905         /* Not uprobe? */
 906         if (!pf->pev->uprobes)
 907                 return;
 908
 909         /* Compiled with optimization? */
 910         if (die_is_optimized_target(&pf->cu_die))
 911                 return;
 912
 913         /* Don't know entrypc? */
 914         if (!pf->addr)
 915                 return;
 916
 917         /* Only FUNC and FUNC@SRC are eligible. */
 918         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 919             pp->offset || pp->abs_address)
 920                 return;
 921
 922         /* Not interested in func parameter? */
 923         if (!perf_probe_with_var(pf->pev))
 924                 return;
 925
 926         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 927                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 928                 pf->addr);
 929
 930         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 931 }
 932
 933 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 934 {
 935         struct probe_finder *pf = data;
 936         struct perf_probe_point *pp = &pf->pev->point;
 937         Dwarf_Addr addr;
 938         int ret;
 939
 940         if (pp->lazy_line)
 941                 ret = find_probe_point_lazy(in_die, pf);
 942         else {
 943                 /* Get probe address */
 944                 if (dwarf_entrypc(in_die, &addr) != 0) {
 945                         pr_warning("Failed to get entry address of %s.\n",
 946                                    dwarf_diename(in_die));
 947                         return -ENOENT;
 948                 }
 949                 if (addr == 0) {
 950                         pr_debug("%s has no valid entry address. skipped.\n",
 951                                  dwarf_diename(in_die));
 952                         return -ENOENT;
 953                 }
 954                 pf->addr = addr;
 955                 pf->addr += pp->offset;
 956                 pr_debug("found inline addr: 0x%jx\n",
 957                          (uintmax_t)pf->addr);
 958
 959                 ret = call_probe_finder(in_die, pf);
 960         }
 961
 962         return ret;
 963 }
 964
 965 /* Callback parameter with return value for libdw */
 966 struct dwarf_callback_param {
 967         void *data;
 968         int retval;
 969 };
 970
 971 /* Search function from function name */
 972 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 973 {
 974         struct dwarf_callback_param *param = data;
 975         struct probe_finder *pf = param->data;
 976         struct perf_probe_point *pp = &pf->pev->point;
 977
 978         /* Check tag and diename */
 979         if (!die_is_func_def(sp_die) ||
 980             !die_match_name(sp_die, pp->function))
 981                 return DWARF_CB_OK;
 982
 983         /* Check declared file */
 984         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 985                 return DWARF_CB_OK;
 986
 987         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
 988                  (unsigned long)dwarf_dieoffset(sp_die));
 989         pf->fname = dwarf_decl_file(sp_die);
 990         if (pp->line) { /* Function relative line */
 991                 dwarf_decl_line(sp_die, &pf->lno);
 992                 pf->lno += pp->line;
 993                 param->retval = find_probe_point_by_line(pf);
 994         } else if (die_is_func_instance(sp_die)) {
 995                 /* Instances always have the entry address */
 996                 dwarf_entrypc(sp_die, &pf->addr);
 997                 /* But in some case the entry address is 0 */
 998                 if (pf->addr == 0) {
 999                         pr_debug("%s has no entry PC. Skipped\n",
1000                                  dwarf_diename(sp_die));
1001                         param->retval = 0;
1002                 /* Real function */
1003                 } else if (pp->lazy_line)
1004                         param->retval = find_probe_point_lazy(sp_die, pf);
1005                 else {
1006                         skip_prologue(sp_die, pf);
1007                         pf->addr += pp->offset;
1008                         /* TODO: Check the address in this function */
1009                         param->retval = call_probe_finder(sp_die, pf);
1010                 }
1011         } else if (!probe_conf.no_inlines) {
1012                 /* Inlined function: search instances */
1013                 param->retval = die_walk_instances(sp_die,
1014                                         probe_point_inline_cb, (void *)pf);
1015                 /* This could be a non-existed inline definition */
1016                 if (param->retval == -ENOENT)
1017                         param->retval = 0;
1018         }
1019
1020         /* We need to find other candidates */
1021         if (strisglob(pp->function) && param->retval >= 0) {
1022                 param->retval = 0;      /* We have to clear the result */
1023                 return DWARF_CB_OK;
1024         }
1025
1026         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1027 }
1028
1029 static int find_probe_point_by_func(struct probe_finder *pf)
1030 {
1031         struct dwarf_callback_param _param = {.data = (void *)pf,
1032                                               .retval = 0};
1033         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1034         return _param.retval;
1035 }
1036
1037 struct pubname_callback_param {
1038         char *function;
1039         char *file;
1040         Dwarf_Die *cu_die;
1041         Dwarf_Die *sp_die;
1042         int found;
1043 };
1044
1045 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1046 {
1047         struct pubname_callback_param *param = data;
1048
1049         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1050                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1051                         return DWARF_CB_OK;
1052
1053                 if (die_match_name(param->sp_die, param->function)) {
1054                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1055                                 return DWARF_CB_OK;
1056
1057                         if (param->file &&
1058                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1059                                 return DWARF_CB_OK;
1060
1061                         param->found = 1;
1062                         return DWARF_CB_ABORT;
1063                 }
1064         }
1065
1066         return DWARF_CB_OK;
1067 }
1068
1069 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1070                                   struct probe_finder *pf)
1071 {
1072         struct perf_probe_point *pp = &pf->pev->point;
1073         Dwarf_Off off, noff;
1074         size_t cuhl;
1075         Dwarf_Die *diep;
1076         int ret = 0;
1077
1078         off = 0;
1079         pf->lcache = intlist__new(NULL);
1080         if (!pf->lcache)
1081                 return -ENOMEM;
1082
1083         /* Fastpath: lookup by function name from .debug_pubnames section */
1084         if (pp->function && !strisglob(pp->function)) {
1085                 struct pubname_callback_param pubname_param = {
1086                         .function = pp->function,
1087                         .file     = pp->file,
1088                         .cu_die   = &pf->cu_die,
1089                         .sp_die   = &pf->sp_die,
1090                         .found    = 0,
1091                 };
1092                 struct dwarf_callback_param probe_param = {
1093                         .data = pf,
1094                 };
1095
1096                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1097                                   &pubname_param, 0);
1098                 if (pubname_param.found) {
1099                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1100                         if (ret)
1101                                 goto found;
1102                 }
1103         }
1104
1105         /* Loop on CUs (Compilation Unit) */
1106         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1107                 /* Get the DIE(Debugging Information Entry) of this CU */
1108                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1109                 if (!diep)
1110                         continue;
1111
1112                 /* Check if target file is included. */
1113                 if (pp->file)
1114                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1115                 else
1116                         pf->fname = NULL;
1117
1118                 if (!pp->file || pf->fname) {
1119                         if (pp->function)
1120                                 ret = find_probe_point_by_func(pf);
1121                         else if (pp->lazy_line)
1122                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1123                         else {
1124                                 pf->lno = pp->line;
1125                                 ret = find_probe_point_by_line(pf);
1126                         }
1127                         if (ret < 0)
1128                                 break;
1129                 }
1130                 off = noff;
1131         }
1132
1133 found:
1134         intlist__delete(pf->lcache);
1135         pf->lcache = NULL;
1136
1137         return ret;
1138 }
1139
1140 /* Find probe points from debuginfo */
1141 static int debuginfo__find_probes(struct debuginfo *dbg,
1142                                   struct probe_finder *pf)
1143 {
1144         int ret = 0;
1145         Elf *elf;
1146         GElf_Ehdr ehdr;
1147
1148         if (pf->cfi_eh || pf->cfi_dbg)
1149                 return debuginfo__find_probe_location(dbg, pf);
1150
1151         /* Get the call frame information from this dwarf */
1152         elf = dwarf_getelf(dbg->dbg);
1153         if (elf == NULL)
1154                 return -EINVAL;
1155
1156         if (gelf_getehdr(elf, &ehdr) == NULL)
1157                 return -EINVAL;
1158
1159         pf->machine = ehdr.e_machine;
1160
1161 #if _ELFUTILS_PREREQ(0, 142)
1162         do {
1163                 GElf_Shdr shdr;
1164
1165                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1166                     shdr.sh_type == SHT_PROGBITS)
1167                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1168
1169                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1170         } while (0);
1171 #endif
1172
1173         ret = debuginfo__find_probe_location(dbg, pf);
1174         return ret;
1175 }
1176
1177 struct local_vars_finder {
1178         struct probe_finder *pf;
1179         struct perf_probe_arg *args;
1180         bool vars;
1181         int max_args;
1182         int nargs;
1183         int ret;
1184 };
1185
1186 /* Collect available variables in this scope */
1187 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1188 {
1189         struct local_vars_finder *vf = data;
1190         struct probe_finder *pf = vf->pf;
1191         int tag;
1192
1193         tag = dwarf_tag(die_mem);
1194         if (tag == DW_TAG_formal_parameter ||
1195             (tag == DW_TAG_variable && vf->vars)) {
1196                 if (convert_variable_location(die_mem, vf->pf->addr,
1197                                               vf->pf->fb_ops, &pf->sp_die,
1198                                               pf->machine, NULL) == 0) {
1199                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1200                         if (vf->args[vf->nargs].var == NULL) {
1201                                 vf->ret = -ENOMEM;
1202                                 return DIE_FIND_CB_END;
1203                         }
1204                         pr_debug(" %s", vf->args[vf->nargs].var);
1205                         vf->nargs++;
1206                 }
1207         }
1208
1209         if (dwarf_haspc(die_mem, vf->pf->addr))
1210                 return DIE_FIND_CB_CONTINUE;
1211         else
1212                 return DIE_FIND_CB_SIBLING;
1213 }
1214
1215 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1216                              struct perf_probe_arg *args)
1217 {
1218         Dwarf_Die die_mem;
1219         int i;
1220         int n = 0;
1221         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1222                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1223
1224         for (i = 0; i < pf->pev->nargs; i++) {
1225                 /* var never be NULL */
1226                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1227                         vf.vars = true;
1228                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1229                         /* Copy normal argument */
1230                         args[n] = pf->pev->args[i];
1231                         n++;
1232                         continue;
1233                 }
1234                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1235                 vf.nargs = n;
1236                 /* Special local variables */
1237                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1238                                &die_mem);
1239                 pr_debug(" (%d)\n", vf.nargs - n);
1240                 if (vf.ret < 0)
1241                         return vf.ret;
1242                 n = vf.nargs;
1243         }
1244         return n;
1245 }
1246
1247 /* Add a found probe point into trace event list */
1248 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1249 {
1250         struct trace_event_finder *tf =
1251                         container_of(pf, struct trace_event_finder, pf);
1252         struct perf_probe_point *pp = &pf->pev->point;
1253         struct probe_trace_event *tev;
1254         struct perf_probe_arg *args = NULL;
1255         int ret, i;
1256
1257         /* Check number of tevs */
1258         if (tf->ntevs == tf->max_tevs) {
1259                 pr_warning("Too many( > %d) probe point found.\n",
1260                            tf->max_tevs);
1261                 return -ERANGE;
1262         }
1263         tev = &tf->tevs[tf->ntevs++];
1264
1265         /* Trace point should be converted from subprogram DIE */
1266         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1267                                      pp->retprobe, pp->function, &tev->point);
1268         if (ret < 0)
1269                 goto end;
1270
1271         tev->point.realname = strdup(dwarf_diename(sc_die));
1272         if (!tev->point.realname) {
1273                 ret = -ENOMEM;
1274                 goto end;
1275         }
1276
1277         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1278                  tev->point.offset);
1279
1280         /* Expand special probe argument if exist */
1281         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1282         if (args == NULL) {
1283                 ret = -ENOMEM;
1284                 goto end;
1285         }
1286
1287         ret = expand_probe_args(sc_die, pf, args);
1288         if (ret < 0)
1289                 goto end;
1290
1291         tev->nargs = ret;
1292         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1293         if (tev->args == NULL) {
1294                 ret = -ENOMEM;
1295                 goto end;
1296         }
1297
1298         /* Find each argument */
1299         for (i = 0; i < tev->nargs; i++) {
1300                 pf->pvar = &args[i];
1301                 pf->tvar = &tev->args[i];
1302                 /* Variable should be found from scope DIE */
1303                 ret = find_variable(sc_die, pf);
1304                 if (ret != 0)
1305                         break;
1306         }
1307
1308 end:
1309         if (ret) {
1310                 clear_probe_trace_event(tev);
1311                 tf->ntevs--;
1312         }
1313         free(args);
1314         return ret;
1315 }
1316
1317 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1318 int debuginfo__find_trace_events(struct debuginfo *dbg,
1319                                  struct perf_probe_event *pev,
1320                                  struct probe_trace_event **tevs)
1321 {
1322         struct trace_event_finder tf = {
1323                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1324                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1325         int ret, i;
1326
1327         /* Allocate result tevs array */
1328         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1329         if (*tevs == NULL)
1330                 return -ENOMEM;
1331
1332         tf.tevs = *tevs;
1333         tf.ntevs = 0;
1334
1335         ret = debuginfo__find_probes(dbg, &tf.pf);
1336         if (ret < 0) {
1337                 for (i = 0; i < tf.ntevs; i++)
1338                         clear_probe_trace_event(&tf.tevs[i]);
1339                 zfree(tevs);
1340                 return ret;
1341         }
1342
1343         return (ret < 0) ? ret : tf.ntevs;
1344 }
1345
1346 /* Collect available variables in this scope */
1347 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1348 {
1349         struct available_var_finder *af = data;
1350         struct variable_list *vl;
1351         struct strbuf buf = STRBUF_INIT;
1352         int tag, ret;
1353
1354         vl = &af->vls[af->nvls - 1];
1355
1356         tag = dwarf_tag(die_mem);
1357         if (tag == DW_TAG_formal_parameter ||
1358             tag == DW_TAG_variable) {
1359                 ret = convert_variable_location(die_mem, af->pf.addr,
1360                                                 af->pf.fb_ops, &af->pf.sp_die,
1361                                                 af->pf.machine, NULL);
1362                 if (ret == 0 || ret == -ERANGE) {
1363                         int ret2;
1364                         bool externs = !af->child;
1365
1366                         if (strbuf_init(&buf, 64) < 0)
1367                                 goto error;
1368
1369                         if (probe_conf.show_location_range) {
1370                                 if (!externs)
1371                                         ret2 = strbuf_add(&buf,
1372                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1373                                 else
1374                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1375                                 if (ret2)
1376                                         goto error;
1377                         }
1378
1379                         ret2 = die_get_varname(die_mem, &buf);
1380
1381                         if (!ret2 && probe_conf.show_location_range &&
1382                                 !externs) {
1383                                 if (strbuf_addch(&buf, '\t') < 0)
1384                                         goto error;
1385                                 ret2 = die_get_var_range(&af->pf.sp_die,
1386                                                         die_mem, &buf);
1387                         }
1388
1389                         pr_debug("Add new var: %s\n", buf.buf);
1390                         if (ret2 == 0) {
1391                                 strlist__add(vl->vars,
1392                                         strbuf_detach(&buf, NULL));
1393                         }
1394                         strbuf_release(&buf);
1395                 }
1396         }
1397
1398         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1399                 return DIE_FIND_CB_CONTINUE;
1400         else
1401                 return DIE_FIND_CB_SIBLING;
1402 error:
1403         strbuf_release(&buf);
1404         pr_debug("Error in strbuf\n");
1405         return DIE_FIND_CB_END;
1406 }
1407
1408 /* Add a found vars into available variables list */
1409 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1410 {
1411         struct available_var_finder *af =
1412                         container_of(pf, struct available_var_finder, pf);
1413         struct perf_probe_point *pp = &pf->pev->point;
1414         struct variable_list *vl;
1415         Dwarf_Die die_mem;
1416         int ret;
1417
1418         /* Check number of tevs */
1419         if (af->nvls == af->max_vls) {
1420                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1421                 return -ERANGE;
1422         }
1423         vl = &af->vls[af->nvls++];
1424
1425         /* Trace point should be converted from subprogram DIE */
1426         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1427                                      pp->retprobe, pp->function, &vl->point);
1428         if (ret < 0)
1429                 return ret;
1430
1431         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1432                  vl->point.offset);
1433
1434         /* Find local variables */
1435         vl->vars = strlist__new(NULL, NULL);
1436         if (vl->vars == NULL)
1437                 return -ENOMEM;
1438         af->child = true;
1439         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1440
1441         /* Find external variables */
1442         if (!probe_conf.show_ext_vars)
1443                 goto out;
1444         /* Don't need to search child DIE for external vars. */
1445         af->child = false;
1446         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1447
1448 out:
1449         if (strlist__empty(vl->vars)) {
1450                 strlist__delete(vl->vars);
1451                 vl->vars = NULL;
1452         }
1453
1454         return ret;
1455 }
1456
1457 /*
1458  * Find available variables at given probe point
1459  * Return the number of found probe points. Return 0 if there is no
1460  * matched probe point. Return <0 if an error occurs.
1461  */
1462 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1463                                       struct perf_probe_event *pev,
1464                                       struct variable_list **vls)
1465 {
1466         struct available_var_finder af = {
1467                         .pf = {.pev = pev, .callback = add_available_vars},
1468                         .mod = dbg->mod,
1469                         .max_vls = probe_conf.max_probes};
1470         int ret;
1471
1472         /* Allocate result vls array */
1473         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1474         if (*vls == NULL)
1475                 return -ENOMEM;
1476
1477         af.vls = *vls;
1478         af.nvls = 0;
1479
1480         ret = debuginfo__find_probes(dbg, &af.pf);
1481         if (ret < 0) {
1482                 /* Free vlist for error */
1483                 while (af.nvls--) {
1484                         zfree(&af.vls[af.nvls].point.symbol);
1485                         strlist__delete(af.vls[af.nvls].vars);
1486                 }
1487                 zfree(vls);
1488                 return ret;
1489         }
1490
1491         return (ret < 0) ? ret : af.nvls;
1492 }
1493
1494 /* For the kernel module, we need a special code to get a DIE */
1495 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1496                                 bool adjust_offset)
1497 {
1498         int n, i;
1499         Elf32_Word shndx;
1500         Elf_Scn *scn;
1501         Elf *elf;
1502         GElf_Shdr mem, *shdr;
1503         const char *p;
1504
1505         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1506         if (!elf)
1507                 return -EINVAL;
1508
1509         /* Get the number of relocations */
1510         n = dwfl_module_relocations(dbg->mod);
1511         if (n < 0)
1512                 return -ENOENT;
1513         /* Search the relocation related .text section */
1514         for (i = 0; i < n; i++) {
1515                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1516                 if (strcmp(p, ".text") == 0) {
1517                         /* OK, get the section header */
1518                         scn = elf_getscn(elf, shndx);
1519                         if (!scn)
1520                                 return -ENOENT;
1521                         shdr = gelf_getshdr(scn, &mem);
1522                         if (!shdr)
1523                                 return -ENOENT;
1524                         *offs = shdr->sh_addr;
1525                         if (adjust_offset)
1526                                 *offs -= shdr->sh_offset;
1527                 }
1528         }
1529         return 0;
1530 }
1531
1532 /* Reverse search */
1533 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1534                                 struct perf_probe_point *ppt)
1535 {
1536         Dwarf_Die cudie, spdie, indie;
1537         Dwarf_Addr _addr = 0, baseaddr = 0;
1538         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1539         int baseline = 0, lineno = 0, ret = 0;
1540
1541         /* We always need to relocate the address for aranges */
1542         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1543                 addr += baseaddr;
1544         /* Find cu die */
1545         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1546                 pr_warning("Failed to find debug information for address %lx\n",
1547                            addr);
1548                 ret = -EINVAL;
1549                 goto end;
1550         }
1551
1552         /* Find a corresponding line (filename and lineno) */
1553         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1554         /* Don't care whether it failed or not */
1555
1556         /* Find a corresponding function (name, baseline and baseaddr) */
1557         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1558                 /* Get function entry information */
1559                 func = basefunc = dwarf_diename(&spdie);
1560                 if (!func ||
1561                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1562                     dwarf_decl_line(&spdie, &baseline) != 0) {
1563                         lineno = 0;
1564                         goto post;
1565                 }
1566
1567                 fname = dwarf_decl_file(&spdie);
1568                 if (addr == (unsigned long)baseaddr) {
1569                         /* Function entry - Relative line number is 0 */
1570                         lineno = baseline;
1571                         goto post;
1572                 }
1573
1574                 /* Track down the inline functions step by step */
1575                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1576                                                 &indie)) {
1577                         /* There is an inline function */
1578                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1579                             _addr == addr) {
1580                                 /*
1581                                  * addr is at an inline function entry.
1582                                  * In this case, lineno should be the call-site
1583                                  * line number. (overwrite lineinfo)
1584                                  */
1585                                 lineno = die_get_call_lineno(&indie);
1586                                 fname = die_get_call_file(&indie);
1587                                 break;
1588                         } else {
1589                                 /*
1590                                  * addr is in an inline function body.
1591                                  * Since lineno points one of the lines
1592                                  * of the inline function, baseline should
1593                                  * be the entry line of the inline function.
1594                                  */
1595                                 tmp = dwarf_diename(&indie);
1596                                 if (!tmp ||
1597                                     dwarf_decl_line(&indie, &baseline) != 0)
1598                                         break;
1599                                 func = tmp;
1600                                 spdie = indie;
1601                         }
1602                 }
1603                 /* Verify the lineno and baseline are in a same file */
1604                 tmp = dwarf_decl_file(&spdie);
1605                 if (!tmp || strcmp(tmp, fname) != 0)
1606                         lineno = 0;
1607         }
1608
1609 post:
1610         /* Make a relative line number or an offset */
1611         if (lineno)
1612                 ppt->line = lineno - baseline;
1613         else if (basefunc) {
1614                 ppt->offset = addr - (unsigned long)baseaddr;
1615                 func = basefunc;
1616         }
1617
1618         /* Duplicate strings */
1619         if (func) {
1620                 ppt->function = strdup(func);
1621                 if (ppt->function == NULL) {
1622                         ret = -ENOMEM;
1623                         goto end;
1624                 }
1625         }
1626         if (fname) {
1627                 ppt->file = strdup(fname);
1628                 if (ppt->file == NULL) {
1629                         zfree(&ppt->function);
1630                         ret = -ENOMEM;
1631                         goto end;
1632                 }
1633         }
1634 end:
1635         if (ret == 0 && (fname || func))
1636                 ret = 1;        /* Found a point */
1637         return ret;
1638 }
1639
1640 /* Add a line and store the src path */
1641 static int line_range_add_line(const char *src, unsigned int lineno,
1642                                struct line_range *lr)
1643 {
1644         /* Copy source path */
1645         if (!lr->path) {
1646                 lr->path = strdup(src);
1647                 if (lr->path == NULL)
1648                         return -ENOMEM;
1649         }
1650         return intlist__add(lr->line_list, lineno);
1651 }
1652
1653 static int line_range_walk_cb(const char *fname, int lineno,
1654                               Dwarf_Addr addr __maybe_unused,
1655                               void *data)
1656 {
1657         struct line_finder *lf = data;
1658         int err;
1659
1660         if ((strtailcmp(fname, lf->fname) != 0) ||
1661             (lf->lno_s > lineno || lf->lno_e < lineno))
1662                 return 0;
1663
1664         err = line_range_add_line(fname, lineno, lf->lr);
1665         if (err < 0 && err != -EEXIST)
1666                 return err;
1667
1668         return 0;
1669 }
1670
1671 /* Find line range from its line number */
1672 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1673 {
1674         int ret;
1675
1676         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1677
1678         /* Update status */
1679         if (ret >= 0)
1680                 if (!intlist__empty(lf->lr->line_list))
1681                         ret = lf->found = 1;
1682                 else
1683                         ret = 0;        /* Lines are not found */
1684         else {
1685                 zfree(&lf->lr->path);
1686         }
1687         return ret;
1688 }
1689
1690 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1691 {
1692         int ret = find_line_range_by_line(in_die, data);
1693
1694         /*
1695          * We have to check all instances of inlined function, because
1696          * some execution paths can be optimized out depends on the
1697          * function argument of instances. However, if an error occurs,
1698          * it should be handled by the caller.
1699          */
1700         return ret < 0 ? ret : 0;
1701 }
1702
1703 /* Search function definition from function name */
1704 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1705 {
1706         struct dwarf_callback_param *param = data;
1707         struct line_finder *lf = param->data;
1708         struct line_range *lr = lf->lr;
1709
1710         /* Check declared file */
1711         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1712                 return DWARF_CB_OK;
1713
1714         if (die_is_func_def(sp_die) &&
1715             die_match_name(sp_die, lr->function)) {
1716                 lf->fname = dwarf_decl_file(sp_die);
1717                 dwarf_decl_line(sp_die, &lr->offset);
1718                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1719                 lf->lno_s = lr->offset + lr->start;
1720                 if (lf->lno_s < 0)      /* Overflow */
1721                         lf->lno_s = INT_MAX;
1722                 lf->lno_e = lr->offset + lr->end;
1723                 if (lf->lno_e < 0)      /* Overflow */
1724                         lf->lno_e = INT_MAX;
1725                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1726                 lr->start = lf->lno_s;
1727                 lr->end = lf->lno_e;
1728                 if (!die_is_func_instance(sp_die))
1729                         param->retval = die_walk_instances(sp_die,
1730                                                 line_range_inline_cb, lf);
1731                 else
1732                         param->retval = find_line_range_by_line(sp_die, lf);
1733                 return DWARF_CB_ABORT;
1734         }
1735         return DWARF_CB_OK;
1736 }
1737
1738 static int find_line_range_by_func(struct line_finder *lf)
1739 {
1740         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1741         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1742         return param.retval;
1743 }
1744
1745 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1746 {
1747         struct line_finder lf = {.lr = lr, .found = 0};
1748         int ret = 0;
1749         Dwarf_Off off = 0, noff;
1750         size_t cuhl;
1751         Dwarf_Die *diep;
1752         const char *comp_dir;
1753
1754         /* Fastpath: lookup by function name from .debug_pubnames section */
1755         if (lr->function) {
1756                 struct pubname_callback_param pubname_param = {
1757                         .function = lr->function, .file = lr->file,
1758                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1759                 struct dwarf_callback_param line_range_param = {
1760                         .data = (void *)&lf, .retval = 0};
1761
1762                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1763                                   &pubname_param, 0);
1764                 if (pubname_param.found) {
1765                         line_range_search_cb(&lf.sp_die, &line_range_param);
1766                         if (lf.found)
1767                                 goto found;
1768                 }
1769         }
1770
1771         /* Loop on CUs (Compilation Unit) */
1772         while (!lf.found && ret >= 0) {
1773                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1774                                  NULL, NULL, NULL) != 0)
1775                         break;
1776
1777                 /* Get the DIE(Debugging Information Entry) of this CU */
1778                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1779                 if (!diep)
1780                         continue;
1781
1782                 /* Check if target file is included. */
1783                 if (lr->file)
1784                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1785                 else
1786                         lf.fname = 0;
1787
1788                 if (!lr->file || lf.fname) {
1789                         if (lr->function)
1790                                 ret = find_line_range_by_func(&lf);
1791                         else {
1792                                 lf.lno_s = lr->start;
1793                                 lf.lno_e = lr->end;
1794                                 ret = find_line_range_by_line(NULL, &lf);
1795                         }
1796                 }
1797                 off = noff;
1798         }
1799
1800 found:
1801         /* Store comp_dir */
1802         if (lf.found) {
1803                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1804                 if (comp_dir) {
1805                         lr->comp_dir = strdup(comp_dir);
1806                         if (!lr->comp_dir)
1807                                 ret = -ENOMEM;
1808                 }
1809         }
1810
1811         pr_debug("path: %s\n", lr->path);
1812         return (ret < 0) ? ret : lf.found;
1813 }
1814
1815 /*
1816  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1817  * and chop off leading directories that do not exist. Result is passed back as
1818  * a newly allocated path on success.
1819  * Return 0 if file was found and readable, -errno otherwise.
1820  */
1821 int get_real_path(const char *raw_path, const char *comp_dir,
1822                          char **new_path)
1823 {
1824         const char *prefix = symbol_conf.source_prefix;
1825
1826         if (!prefix) {
1827                 if (raw_path[0] != '/' && comp_dir)
1828                         /* If not an absolute path, try to use comp_dir */
1829                         prefix = comp_dir;
1830                 else {
1831                         if (access(raw_path, R_OK) == 0) {
1832                                 *new_path = strdup(raw_path);
1833                                 return *new_path ? 0 : -ENOMEM;
1834                         } else
1835                                 return -errno;
1836                 }
1837         }
1838
1839         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1840         if (!*new_path)
1841                 return -ENOMEM;
1842
1843         for (;;) {
1844                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1845
1846                 if (access(*new_path, R_OK) == 0)
1847                         return 0;
1848
1849                 if (!symbol_conf.source_prefix) {
1850                         /* In case of searching comp_dir, don't retry */
1851                         zfree(new_path);
1852                         return -errno;
1853                 }
1854
1855                 switch (errno) {
1856                 case ENAMETOOLONG:
1857                 case ENOENT:
1858                 case EROFS:
1859                 case EFAULT:
1860                         raw_path = strchr(++raw_path, '/');
1861                         if (!raw_path) {
1862                                 zfree(new_path);
1863                                 return -ENOENT;
1864                         }
1865                         continue;
1866
1867                 default:
1868                         zfree(new_path);
1869                         return -errno;
1870                 }
1871         }
1872 }