tools/perf/util/probe-finder.c

   1 /*
   2  * probe-finder.c : C expression to kprobe event converter
   3  *
   4  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  */
  21
  22 #include <sys/utsname.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <unistd.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <stdarg.h>
  32 #include <dwarf-regs.h>
  33
  34 #include <linux/bitops.h>
  35 #include "event.h"
  36 #include "dso.h"
  37 #include "debug.h"
  38 #include "intlist.h"
  39 #include "util.h"
  40 #include "symbol.h"
  41 #include "probe-finder.h"
  42
  43 /* Kprobe tracer basic type is up to u64 */
  44 #define MAX_BASIC_TYPE_BITS     64
  45
  46 /* Dwarf FL wrappers */
  47 static char *debuginfo_path;    /* Currently dummy */
  48
  49 static const Dwfl_Callbacks offline_callbacks = {
  50         .find_debuginfo = dwfl_standard_find_debuginfo,
  51         .debuginfo_path = &debuginfo_path,
  52
  53         .section_address = dwfl_offline_section_address,
  54
  55         /* We use this table for core files too.  */
  56         .find_elf = dwfl_build_id_find_elf,
  57 };
  58
  59 /* Get a Dwarf from offline image */
  60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  61                                          const char *path)
  62 {
  63         int fd;
  64
  65         fd = open(path, O_RDONLY);
  66         if (fd < 0)
  67                 return fd;
  68
  69         dbg->dwfl = dwfl_begin(&offline_callbacks);
  70         if (!dbg->dwfl)
  71                 goto error;
  72
  73         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  74         if (!dbg->mod)
  75                 goto error;
  76
  77         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  78         if (!dbg->dbg)
  79                 goto error;
  80
  81         return 0;
  82 error:
  83         if (dbg->dwfl)
  84                 dwfl_end(dbg->dwfl);
  85         else
  86                 close(fd);
  87         memset(dbg, 0, sizeof(*dbg));
  88
  89         return -ENOENT;
  90 }
  91
  92 static struct debuginfo *__debuginfo__new(const char *path)
  93 {
  94         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  95         if (!dbg)
  96                 return NULL;
  97
  98         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  99                 zfree(&dbg);
 100         if (dbg)
 101                 pr_debug("Open Debuginfo file: %s\n", path);
 102         return dbg;
 103 }
 104
 105 enum dso_binary_type distro_dwarf_types[] = {
 106         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 107         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 108         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 109         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 110         DSO_BINARY_TYPE__NOT_FOUND,
 111 };
 112
 113 struct debuginfo *debuginfo__new(const char *path)
 114 {
 115         enum dso_binary_type *type;
 116         char buf[PATH_MAX], nil = '\0';
 117         struct dso *dso;
 118         struct debuginfo *dinfo = NULL;
 119
 120         /* Try to open distro debuginfo files */
 121         dso = dso__new(path);
 122         if (!dso)
 123                 goto out;
 124
 125         for (type = distro_dwarf_types;
 126              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 127              type++) {
 128                 if (dso__read_binary_type_filename(dso, *type, &nil,
 129                                                    buf, PATH_MAX) < 0)
 130                         continue;
 131                 dinfo = __debuginfo__new(buf);
 132         }
 133         dso__delete(dso);
 134
 135 out:
 136         /* if failed to open all distro debuginfo, open given binary */
 137         return dinfo ? : __debuginfo__new(path);
 138 }
 139
 140 void debuginfo__delete(struct debuginfo *dbg)
 141 {
 142         if (dbg) {
 143                 if (dbg->dwfl)
 144                         dwfl_end(dbg->dwfl);
 145                 free(dbg);
 146         }
 147 }
 148
 149 /*
 150  * Probe finder related functions
 151  */
 152
 153 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 154 {
 155         struct probe_trace_arg_ref *ref;
 156         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 157         if (ref != NULL)
 158                 ref->offset = offs;
 159         return ref;
 160 }
 161
 162 /*
 163  * Convert a location into trace_arg.
 164  * If tvar == NULL, this just checks variable can be converted.
 165  * If fentry == true and vr_die is a parameter, do huristic search
 166  * for the location fuzzed by function entry mcount.
 167  */
 168 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 169                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 170                                      struct probe_trace_arg *tvar)
 171 {
 172         Dwarf_Attribute attr;
 173         Dwarf_Addr tmp = 0;
 174         Dwarf_Op *op;
 175         size_t nops;
 176         unsigned int regn;
 177         Dwarf_Word offs = 0;
 178         bool ref = false;
 179         const char *regs;
 180         int ret, ret2 = 0;
 181
 182         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 183                 goto static_var;
 184
 185         /* TODO: handle more than 1 exprs */
 186         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 187                 return -EINVAL; /* Broken DIE ? */
 188         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 189                 ret = dwarf_entrypc(sp_die, &tmp);
 190                 if (ret)
 191                         return -ENOENT;
 192
 193                 if (probe_conf.show_location_range &&
 194                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 195                         ret2 = -ERANGE;
 196                 } else if (addr != tmp ||
 197                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 198                         return -ENOENT;
 199                 }
 200
 201                 ret = dwarf_highpc(sp_die, &tmp);
 202                 if (ret)
 203                         return -ENOENT;
 204                 /*
 205                  * This is fuzzed by fentry mcount. We try to find the
 206                  * parameter location at the earliest address.
 207                  */
 208                 for (addr += 1; addr <= tmp; addr++) {
 209                         if (dwarf_getlocation_addr(&attr, addr, &op,
 210                                                    &nops, 1) > 0)
 211                                 goto found;
 212                 }
 213                 return -ENOENT;
 214         }
 215 found:
 216         if (nops == 0)
 217                 /* TODO: Support const_value */
 218                 return -ENOENT;
 219
 220         if (op->atom == DW_OP_addr) {
 221 static_var:
 222                 if (!tvar)
 223                         return ret2;
 224                 /* Static variables on memory (not stack), make @varname */
 225                 ret = strlen(dwarf_diename(vr_die));
 226                 tvar->value = zalloc(ret + 2);
 227                 if (tvar->value == NULL)
 228                         return -ENOMEM;
 229                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 230                 tvar->ref = alloc_trace_arg_ref((long)offs);
 231                 if (tvar->ref == NULL)
 232                         return -ENOMEM;
 233                 return ret2;
 234         }
 235
 236         /* If this is based on frame buffer, set the offset */
 237         if (op->atom == DW_OP_fbreg) {
 238                 if (fb_ops == NULL)
 239                         return -ENOTSUP;
 240                 ref = true;
 241                 offs = op->number;
 242                 op = &fb_ops[0];
 243         }
 244
 245         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 246                 regn = op->atom - DW_OP_breg0;
 247                 offs += op->number;
 248                 ref = true;
 249         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 250                 regn = op->atom - DW_OP_reg0;
 251         } else if (op->atom == DW_OP_bregx) {
 252                 regn = op->number;
 253                 offs += op->number2;
 254                 ref = true;
 255         } else if (op->atom == DW_OP_regx) {
 256                 regn = op->number;
 257         } else {
 258                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 259                 return -ENOTSUP;
 260         }
 261
 262         if (!tvar)
 263                 return ret2;
 264
 265         regs = get_arch_regstr(regn);
 266         if (!regs) {
 267                 /* This should be a bug in DWARF or this tool */
 268                 pr_warning("Mapping for the register number %u "
 269                            "missing on this architecture.\n", regn);
 270                 return -ENOTSUP;
 271         }
 272
 273         tvar->value = strdup(regs);
 274         if (tvar->value == NULL)
 275                 return -ENOMEM;
 276
 277         if (ref) {
 278                 tvar->ref = alloc_trace_arg_ref((long)offs);
 279                 if (tvar->ref == NULL)
 280                         return -ENOMEM;
 281         }
 282         return ret2;
 283 }
 284
 285 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 286
 287 static int convert_variable_type(Dwarf_Die *vr_die,
 288                                  struct probe_trace_arg *tvar,
 289                                  const char *cast)
 290 {
 291         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 292         Dwarf_Die type;
 293         char buf[16];
 294         char sbuf[STRERR_BUFSIZE];
 295         int bsize, boffs, total;
 296         int ret;
 297
 298         /* TODO: check all types */
 299         if (cast && strcmp(cast, "string") != 0) {
 300                 /* Non string type is OK */
 301                 tvar->type = strdup(cast);
 302                 return (tvar->type == NULL) ? -ENOMEM : 0;
 303         }
 304
 305         bsize = dwarf_bitsize(vr_die);
 306         if (bsize > 0) {
 307                 /* This is a bitfield */
 308                 boffs = dwarf_bitoffset(vr_die);
 309                 total = dwarf_bytesize(vr_die);
 310                 if (boffs < 0 || total < 0)
 311                         return -ENOENT;
 312                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 313                                 BYTES_TO_BITS(total));
 314                 goto formatted;
 315         }
 316
 317         if (die_get_real_type(vr_die, &type) == NULL) {
 318                 pr_warning("Failed to get a type information of %s.\n",
 319                            dwarf_diename(vr_die));
 320                 return -ENOENT;
 321         }
 322
 323         pr_debug("%s type is %s.\n",
 324                  dwarf_diename(vr_die), dwarf_diename(&type));
 325
 326         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 327                 ret = dwarf_tag(&type);
 328                 if (ret != DW_TAG_pointer_type &&
 329                     ret != DW_TAG_array_type) {
 330                         pr_warning("Failed to cast into string: "
 331                                    "%s(%s) is not a pointer nor array.\n",
 332                                    dwarf_diename(vr_die), dwarf_diename(&type));
 333                         return -EINVAL;
 334                 }
 335                 if (die_get_real_type(&type, &type) == NULL) {
 336                         pr_warning("Failed to get a type"
 337                                    " information.\n");
 338                         return -ENOENT;
 339                 }
 340                 if (ret == DW_TAG_pointer_type) {
 341                         while (*ref_ptr)
 342                                 ref_ptr = &(*ref_ptr)->next;
 343                         /* Add new reference with offset +0 */
 344                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 345                         if (*ref_ptr == NULL) {
 346                                 pr_warning("Out of memory error\n");
 347                                 return -ENOMEM;
 348                         }
 349                 }
 350                 if (!die_compare_name(&type, "char") &&
 351                     !die_compare_name(&type, "unsigned char")) {
 352                         pr_warning("Failed to cast into string: "
 353                                    "%s is not (unsigned) char *.\n",
 354                                    dwarf_diename(vr_die));
 355                         return -EINVAL;
 356                 }
 357                 tvar->type = strdup(cast);
 358                 return (tvar->type == NULL) ? -ENOMEM : 0;
 359         }
 360
 361         ret = dwarf_bytesize(&type);
 362         if (ret <= 0)
 363                 /* No size ... try to use default type */
 364                 return 0;
 365         ret = BYTES_TO_BITS(ret);
 366
 367         /* Check the bitwidth */
 368         if (ret > MAX_BASIC_TYPE_BITS) {
 369                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 370                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 371                 ret = MAX_BASIC_TYPE_BITS;
 372         }
 373         ret = snprintf(buf, 16, "%c%d",
 374                        die_is_signed_type(&type) ? 's' : 'u', ret);
 375
 376 formatted:
 377         if (ret < 0 || ret >= 16) {
 378                 if (ret >= 16)
 379                         ret = -E2BIG;
 380                 pr_warning("Failed to convert variable type: %s\n",
 381                            strerror_r(-ret, sbuf, sizeof(sbuf)));
 382                 return ret;
 383         }
 384         tvar->type = strdup(buf);
 385         if (tvar->type == NULL)
 386                 return -ENOMEM;
 387         return 0;
 388 }
 389
 390 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 391                                     struct perf_probe_arg_field *field,
 392                                     struct probe_trace_arg_ref **ref_ptr,
 393                                     Dwarf_Die *die_mem)
 394 {
 395         struct probe_trace_arg_ref *ref = *ref_ptr;
 396         Dwarf_Die type;
 397         Dwarf_Word offs;
 398         int ret, tag;
 399
 400         pr_debug("converting %s in %s\n", field->name, varname);
 401         if (die_get_real_type(vr_die, &type) == NULL) {
 402                 pr_warning("Failed to get the type of %s.\n", varname);
 403                 return -ENOENT;
 404         }
 405         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 406         tag = dwarf_tag(&type);
 407
 408         if (field->name[0] == '[' &&
 409             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 410                 if (field->next)
 411                         /* Save original type for next field */
 412                         memcpy(die_mem, &type, sizeof(*die_mem));
 413                 /* Get the type of this array */
 414                 if (die_get_real_type(&type, &type) == NULL) {
 415                         pr_warning("Failed to get the type of %s.\n", varname);
 416                         return -ENOENT;
 417                 }
 418                 pr_debug2("Array real type: (%x)\n",
 419                          (unsigned)dwarf_dieoffset(&type));
 420                 if (tag == DW_TAG_pointer_type) {
 421                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 422                         if (ref == NULL)
 423                                 return -ENOMEM;
 424                         if (*ref_ptr)
 425                                 (*ref_ptr)->next = ref;
 426                         else
 427                                 *ref_ptr = ref;
 428                 }
 429                 ref->offset += dwarf_bytesize(&type) * field->index;
 430                 if (!field->next)
 431                         /* Save vr_die for converting types */
 432                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 433                 goto next;
 434         } else if (tag == DW_TAG_pointer_type) {
 435                 /* Check the pointer and dereference */
 436                 if (!field->ref) {
 437                         pr_err("Semantic error: %s must be referred by '->'\n",
 438                                field->name);
 439                         return -EINVAL;
 440                 }
 441                 /* Get the type pointed by this pointer */
 442                 if (die_get_real_type(&type, &type) == NULL) {
 443                         pr_warning("Failed to get the type of %s.\n", varname);
 444                         return -ENOENT;
 445                 }
 446                 /* Verify it is a data structure  */
 447                 tag = dwarf_tag(&type);
 448                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 449                         pr_warning("%s is not a data structure nor an union.\n",
 450                                    varname);
 451                         return -EINVAL;
 452                 }
 453
 454                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 455                 if (ref == NULL)
 456                         return -ENOMEM;
 457                 if (*ref_ptr)
 458                         (*ref_ptr)->next = ref;
 459                 else
 460                         *ref_ptr = ref;
 461         } else {
 462                 /* Verify it is a data structure  */
 463                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 464                         pr_warning("%s is not a data structure nor an union.\n",
 465                                    varname);
 466                         return -EINVAL;
 467                 }
 468                 if (field->name[0] == '[') {
 469                         pr_err("Semantic error: %s is not a pointer"
 470                                " nor array.\n", varname);
 471                         return -EINVAL;
 472                 }
 473                 /* While prcessing unnamed field, we don't care about this */
 474                 if (field->ref && dwarf_diename(vr_die)) {
 475                         pr_err("Semantic error: %s must be referred by '.'\n",
 476                                field->name);
 477                         return -EINVAL;
 478                 }
 479                 if (!ref) {
 480                         pr_warning("Structure on a register is not "
 481                                    "supported yet.\n");
 482                         return -ENOTSUP;
 483                 }
 484         }
 485
 486         if (die_find_member(&type, field->name, die_mem) == NULL) {
 487                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 488                            dwarf_diename(&type), field->name);
 489                 return -EINVAL;
 490         }
 491
 492         /* Get the offset of the field */
 493         if (tag == DW_TAG_union_type) {
 494                 offs = 0;
 495         } else {
 496                 ret = die_get_data_member_location(die_mem, &offs);
 497                 if (ret < 0) {
 498                         pr_warning("Failed to get the offset of %s.\n",
 499                                    field->name);
 500                         return ret;
 501                 }
 502         }
 503         ref->offset += (long)offs;
 504
 505         /* If this member is unnamed, we need to reuse this field */
 506         if (!dwarf_diename(die_mem))
 507                 return convert_variable_fields(die_mem, varname, field,
 508                                                 &ref, die_mem);
 509
 510 next:
 511         /* Converting next field */
 512         if (field->next)
 513                 return convert_variable_fields(die_mem, field->name,
 514                                         field->next, &ref, die_mem);
 515         else
 516                 return 0;
 517 }
 518
 519 /* Show a variables in kprobe event format */
 520 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 521 {
 522         Dwarf_Die die_mem;
 523         int ret;
 524
 525         pr_debug("Converting variable %s into trace event.\n",
 526                  dwarf_diename(vr_die));
 527
 528         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 529                                         &pf->sp_die, pf->tvar);
 530         if (ret == -ENOENT || ret == -EINVAL)
 531                 pr_err("Failed to find the location of %s at this address.\n"
 532                        " Perhaps, it has been optimized out.\n", pf->pvar->var);
 533         else if (ret == -ENOTSUP)
 534                 pr_err("Sorry, we don't support this variable location yet.\n");
 535         else if (ret == 0 && pf->pvar->field) {
 536                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 537                                               pf->pvar->field, &pf->tvar->ref,
 538                                               &die_mem);
 539                 vr_die = &die_mem;
 540         }
 541         if (ret == 0)
 542                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 543         /* *expr will be cached in libdw. Don't free it. */
 544         return ret;
 545 }
 546
 547 /* Find a variable in a scope DIE */
 548 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 549 {
 550         Dwarf_Die vr_die;
 551         char buf[32], *ptr;
 552         int ret = 0;
 553
 554         if (!is_c_varname(pf->pvar->var)) {
 555                 /* Copy raw parameters */
 556                 pf->tvar->value = strdup(pf->pvar->var);
 557                 if (pf->tvar->value == NULL)
 558                         return -ENOMEM;
 559                 if (pf->pvar->type) {
 560                         pf->tvar->type = strdup(pf->pvar->type);
 561                         if (pf->tvar->type == NULL)
 562                                 return -ENOMEM;
 563                 }
 564                 if (pf->pvar->name) {
 565                         pf->tvar->name = strdup(pf->pvar->name);
 566                         if (pf->tvar->name == NULL)
 567                                 return -ENOMEM;
 568                 } else
 569                         pf->tvar->name = NULL;
 570                 return 0;
 571         }
 572
 573         if (pf->pvar->name)
 574                 pf->tvar->name = strdup(pf->pvar->name);
 575         else {
 576                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 577                 if (ret < 0)
 578                         return ret;
 579                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 580                 if (ptr)
 581                         *ptr = '_';
 582                 pf->tvar->name = strdup(buf);
 583         }
 584         if (pf->tvar->name == NULL)
 585                 return -ENOMEM;
 586
 587         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 588         /* Search child die for local variables and parameters. */
 589         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 590                 /* Search again in global variables */
 591                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 592                                                 0, &vr_die)) {
 593                         pr_warning("Failed to find '%s' in this function.\n",
 594                                    pf->pvar->var);
 595                         ret = -ENOENT;
 596                 }
 597         }
 598         if (ret >= 0)
 599                 ret = convert_variable(&vr_die, pf);
 600
 601         return ret;
 602 }
 603
 604 /* Convert subprogram DIE to trace point */
 605 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 606                                   Dwarf_Addr paddr, bool retprobe,
 607                                   struct probe_trace_point *tp)
 608 {
 609         Dwarf_Addr eaddr, highaddr;
 610         GElf_Sym sym;
 611         const char *symbol;
 612
 613         /* Verify the address is correct */
 614         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 615                 pr_warning("Failed to get entry address of %s\n",
 616                            dwarf_diename(sp_die));
 617                 return -ENOENT;
 618         }
 619         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 620                 pr_warning("Failed to get end address of %s\n",
 621                            dwarf_diename(sp_die));
 622                 return -ENOENT;
 623         }
 624         if (paddr > highaddr) {
 625                 pr_warning("Offset specified is greater than size of %s\n",
 626                            dwarf_diename(sp_die));
 627                 return -EINVAL;
 628         }
 629
 630         symbol = dwarf_diename(sp_die);
 631         if (!symbol) {
 632                 /* Try to get the symbol name from symtab */
 633                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 634                 if (!symbol) {
 635                         pr_warning("Failed to find symbol at 0x%lx\n",
 636                                    (unsigned long)paddr);
 637                         return -ENOENT;
 638                 }
 639                 eaddr = sym.st_value;
 640         }
 641         tp->offset = (unsigned long)(paddr - eaddr);
 642         tp->address = (unsigned long)paddr;
 643         tp->symbol = strdup(symbol);
 644         if (!tp->symbol)
 645                 return -ENOMEM;
 646
 647         /* Return probe must be on the head of a subprogram */
 648         if (retprobe) {
 649                 if (eaddr != paddr) {
 650                         pr_warning("Return probe must be on the head of"
 651                                    " a real function.\n");
 652                         return -EINVAL;
 653                 }
 654                 tp->retprobe = true;
 655         }
 656
 657         return 0;
 658 }
 659
 660 /* Call probe_finder callback with scope DIE */
 661 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 662 {
 663         Dwarf_Attribute fb_attr;
 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                         pr_warning("Failed to find probe point in any "
 676                                    "functions.\n");
 677                         return -ENOENT;
 678                 }
 679         } else
 680                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 681
 682         /* Get the frame base attribute/ops from subprogram */
 683         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 684         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 685         if (ret <= 0 || nops == 0) {
 686                 pf->fb_ops = NULL;
 687 #if _ELFUTILS_PREREQ(0, 142)
 688         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 689                    pf->cfi != NULL) {
 690                 Dwarf_Frame *frame;
 691                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 692                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 693                         pr_warning("Failed to get call frame on 0x%jx\n",
 694                                    (uintmax_t)pf->addr);
 695                         return -ENOENT;
 696                 }
 697 #endif
 698         }
 699
 700         /* Call finder's callback handler */
 701         ret = pf->callback(sc_die, pf);
 702
 703         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 704         pf->fb_ops = NULL;
 705
 706         return ret;
 707 }
 708
 709 struct find_scope_param {
 710         const char *function;
 711         const char *file;
 712         int line;
 713         int diff;
 714         Dwarf_Die *die_mem;
 715         bool found;
 716 };
 717
 718 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 719 {
 720         struct find_scope_param *fsp = data;
 721         const char *file;
 722         int lno;
 723
 724         /* Skip if declared file name does not match */
 725         if (fsp->file) {
 726                 file = dwarf_decl_file(fn_die);
 727                 if (!file || strcmp(fsp->file, file) != 0)
 728                         return 0;
 729         }
 730         /* If the function name is given, that's what user expects */
 731         if (fsp->function) {
 732                 if (die_match_name(fn_die, fsp->function)) {
 733                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 734                         fsp->found = true;
 735                         return 1;
 736                 }
 737         } else {
 738                 /* With the line number, find the nearest declared DIE */
 739                 dwarf_decl_line(fn_die, &lno);
 740                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 741                         /* Keep a candidate and continue */
 742                         fsp->diff = fsp->line - lno;
 743                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 744                         fsp->found = true;
 745                 }
 746         }
 747         return 0;
 748 }
 749
 750 /* Find an appropriate scope fits to given conditions */
 751 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 752 {
 753         struct find_scope_param fsp = {
 754                 .function = pf->pev->point.function,
 755                 .file = pf->fname,
 756                 .line = pf->lno,
 757                 .diff = INT_MAX,
 758                 .die_mem = die_mem,
 759                 .found = false,
 760         };
 761
 762         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 763
 764         return fsp.found ? die_mem : NULL;
 765 }
 766
 767 static int probe_point_line_walker(const char *fname, int lineno,
 768                                    Dwarf_Addr addr, void *data)
 769 {
 770         struct probe_finder *pf = data;
 771         Dwarf_Die *sc_die, die_mem;
 772         int ret;
 773
 774         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 775                 return 0;
 776
 777         pf->addr = addr;
 778         sc_die = find_best_scope(pf, &die_mem);
 779         if (!sc_die) {
 780                 pr_warning("Failed to find scope of probe point.\n");
 781                 return -ENOENT;
 782         }
 783
 784         ret = call_probe_finder(sc_die, pf);
 785
 786         /* Continue if no error, because the line will be in inline function */
 787         return ret < 0 ? ret : 0;
 788 }
 789
 790 /* Find probe point from its line number */
 791 static int find_probe_point_by_line(struct probe_finder *pf)
 792 {
 793         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 794 }
 795
 796 /* Find lines which match lazy pattern */
 797 static int find_lazy_match_lines(struct intlist *list,
 798                                  const char *fname, const char *pat)
 799 {
 800         FILE *fp;
 801         char *line = NULL;
 802         size_t line_len;
 803         ssize_t len;
 804         int count = 0, linenum = 1;
 805         char sbuf[STRERR_BUFSIZE];
 806
 807         fp = fopen(fname, "r");
 808         if (!fp) {
 809                 pr_warning("Failed to open %s: %s\n", fname,
 810                            strerror_r(errno, sbuf, sizeof(sbuf)));
 811                 return -errno;
 812         }
 813
 814         while ((len = getline(&line, &line_len, fp)) > 0) {
 815
 816                 if (line[len - 1] == '\n')
 817                         line[len - 1] = '\0';
 818
 819                 if (strlazymatch(line, pat)) {
 820                         intlist__add(list, linenum);
 821                         count++;
 822                 }
 823                 linenum++;
 824         }
 825
 826         if (ferror(fp))
 827                 count = -errno;
 828         free(line);
 829         fclose(fp);
 830
 831         if (count == 0)
 832                 pr_debug("No matched lines found in %s.\n", fname);
 833         return count;
 834 }
 835
 836 static int probe_point_lazy_walker(const char *fname, int lineno,
 837                                    Dwarf_Addr addr, void *data)
 838 {
 839         struct probe_finder *pf = data;
 840         Dwarf_Die *sc_die, die_mem;
 841         int ret;
 842
 843         if (!intlist__has_entry(pf->lcache, lineno) ||
 844             strtailcmp(fname, pf->fname) != 0)
 845                 return 0;
 846
 847         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 848                  lineno, (unsigned long long)addr);
 849         pf->addr = addr;
 850         pf->lno = lineno;
 851         sc_die = find_best_scope(pf, &die_mem);
 852         if (!sc_die) {
 853                 pr_warning("Failed to find scope of probe point.\n");
 854                 return -ENOENT;
 855         }
 856
 857         ret = call_probe_finder(sc_die, pf);
 858
 859         /*
 860          * Continue if no error, because the lazy pattern will match
 861          * to other lines
 862          */
 863         return ret < 0 ? ret : 0;
 864 }
 865
 866 /* Find probe points from lazy pattern  */
 867 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 868 {
 869         int ret = 0;
 870         char *fpath;
 871
 872         if (intlist__empty(pf->lcache)) {
 873                 const char *comp_dir;
 874
 875                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 876                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 877                 if (ret < 0) {
 878                         pr_warning("Failed to find source file path.\n");
 879                         return ret;
 880                 }
 881
 882                 /* Matching lazy line pattern */
 883                 ret = find_lazy_match_lines(pf->lcache, fpath,
 884                                             pf->pev->point.lazy_line);
 885                 free(fpath);
 886                 if (ret <= 0)
 887                         return ret;
 888         }
 889
 890         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 891 }
 892
 893 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 894 {
 895         struct probe_finder *pf = data;
 896         struct perf_probe_point *pp = &pf->pev->point;
 897         Dwarf_Addr addr;
 898         int ret;
 899
 900         if (pp->lazy_line)
 901                 ret = find_probe_point_lazy(in_die, pf);
 902         else {
 903                 /* Get probe address */
 904                 if (dwarf_entrypc(in_die, &addr) != 0) {
 905                         pr_warning("Failed to get entry address of %s.\n",
 906                                    dwarf_diename(in_die));
 907                         return -ENOENT;
 908                 }
 909                 pf->addr = addr;
 910                 pf->addr += pp->offset;
 911                 pr_debug("found inline addr: 0x%jx\n",
 912                          (uintmax_t)pf->addr);
 913
 914                 ret = call_probe_finder(in_die, pf);
 915         }
 916
 917         return ret;
 918 }
 919
 920 /* Callback parameter with return value for libdw */
 921 struct dwarf_callback_param {
 922         void *data;
 923         int retval;
 924 };
 925
 926 /* Search function from function name */
 927 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 928 {
 929         struct dwarf_callback_param *param = data;
 930         struct probe_finder *pf = param->data;
 931         struct perf_probe_point *pp = &pf->pev->point;
 932
 933         /* Check tag and diename */
 934         if (!die_is_func_def(sp_die) ||
 935             !die_match_name(sp_die, pp->function))
 936                 return DWARF_CB_OK;
 937
 938         /* Check declared file */
 939         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 940                 return DWARF_CB_OK;
 941
 942         pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
 943         pf->fname = dwarf_decl_file(sp_die);
 944         if (pp->line) { /* Function relative line */
 945                 dwarf_decl_line(sp_die, &pf->lno);
 946                 pf->lno += pp->line;
 947                 param->retval = find_probe_point_by_line(pf);
 948         } else if (die_is_func_instance(sp_die)) {
 949                 /* Instances always have the entry address */
 950                 dwarf_entrypc(sp_die, &pf->addr);
 951                 /* Real function */
 952                 if (pp->lazy_line)
 953                         param->retval = find_probe_point_lazy(sp_die, pf);
 954                 else {
 955                         pf->addr += pp->offset;
 956                         /* TODO: Check the address in this function */
 957                         param->retval = call_probe_finder(sp_die, pf);
 958                 }
 959         } else if (!probe_conf.no_inlines) {
 960                 /* Inlined function: search instances */
 961                 param->retval = die_walk_instances(sp_die,
 962                                         probe_point_inline_cb, (void *)pf);
 963                 /* This could be a non-existed inline definition */
 964                 if (param->retval == -ENOENT && strisglob(pp->function))
 965                         param->retval = 0;
 966         }
 967
 968         /* We need to find other candidates */
 969         if (strisglob(pp->function) && param->retval >= 0) {
 970                 param->retval = 0;      /* We have to clear the result */
 971                 return DWARF_CB_OK;
 972         }
 973
 974         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 975 }
 976
 977 static int find_probe_point_by_func(struct probe_finder *pf)
 978 {
 979         struct dwarf_callback_param _param = {.data = (void *)pf,
 980                                               .retval = 0};
 981         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 982         return _param.retval;
 983 }
 984
 985 struct pubname_callback_param {
 986         char *function;
 987         char *file;
 988         Dwarf_Die *cu_die;
 989         Dwarf_Die *sp_die;
 990         int found;
 991 };
 992
 993 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
 994 {
 995         struct pubname_callback_param *param = data;
 996
 997         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
 998                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
 999                         return DWARF_CB_OK;
1000
1001                 if (die_match_name(param->sp_die, param->function)) {
1002                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1003                                 return DWARF_CB_OK;
1004
1005                         if (param->file &&
1006                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1007                                 return DWARF_CB_OK;
1008
1009                         param->found = 1;
1010                         return DWARF_CB_ABORT;
1011                 }
1012         }
1013
1014         return DWARF_CB_OK;
1015 }
1016
1017 /* Find probe points from debuginfo */
1018 static int debuginfo__find_probes(struct debuginfo *dbg,
1019                                   struct probe_finder *pf)
1020 {
1021         struct perf_probe_point *pp = &pf->pev->point;
1022         Dwarf_Off off, noff;
1023         size_t cuhl;
1024         Dwarf_Die *diep;
1025         int ret = 0;
1026
1027 #if _ELFUTILS_PREREQ(0, 142)
1028         Elf *elf;
1029         GElf_Ehdr ehdr;
1030         GElf_Shdr shdr;
1031
1032         /* Get the call frame information from this dwarf */
1033         elf = dwarf_getelf(dbg->dbg);
1034         if (elf == NULL)
1035                 return -EINVAL;
1036
1037         if (gelf_getehdr(elf, &ehdr) == NULL)
1038                 return -EINVAL;
1039
1040         if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1041             shdr.sh_type == SHT_PROGBITS) {
1042                 pf->cfi = dwarf_getcfi_elf(elf);
1043         } else {
1044                 pf->cfi = dwarf_getcfi(dbg->dbg);
1045         }
1046 #endif
1047
1048         off = 0;
1049         pf->lcache = intlist__new(NULL);
1050         if (!pf->lcache)
1051                 return -ENOMEM;
1052
1053         /* Fastpath: lookup by function name from .debug_pubnames section */
1054         if (pp->function && !strisglob(pp->function)) {
1055                 struct pubname_callback_param pubname_param = {
1056                         .function = pp->function,
1057                         .file     = pp->file,
1058                         .cu_die   = &pf->cu_die,
1059                         .sp_die   = &pf->sp_die,
1060                         .found    = 0,
1061                 };
1062                 struct dwarf_callback_param probe_param = {
1063                         .data = pf,
1064                 };
1065
1066                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1067                                   &pubname_param, 0);
1068                 if (pubname_param.found) {
1069                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1070                         if (ret)
1071                                 goto found;
1072                 }
1073         }
1074
1075         /* Loop on CUs (Compilation Unit) */
1076         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1077                 /* Get the DIE(Debugging Information Entry) of this CU */
1078                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1079                 if (!diep)
1080                         continue;
1081
1082                 /* Check if target file is included. */
1083                 if (pp->file)
1084                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1085                 else
1086                         pf->fname = NULL;
1087
1088                 if (!pp->file || pf->fname) {
1089                         if (pp->function)
1090                                 ret = find_probe_point_by_func(pf);
1091                         else if (pp->lazy_line)
1092                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1093                         else {
1094                                 pf->lno = pp->line;
1095                                 ret = find_probe_point_by_line(pf);
1096                         }
1097                         if (ret < 0)
1098                                 break;
1099                 }
1100                 off = noff;
1101         }
1102
1103 found:
1104         intlist__delete(pf->lcache);
1105         pf->lcache = NULL;
1106
1107         return ret;
1108 }
1109
1110 struct local_vars_finder {
1111         struct probe_finder *pf;
1112         struct perf_probe_arg *args;
1113         bool vars;
1114         int max_args;
1115         int nargs;
1116         int ret;
1117 };
1118
1119 /* Collect available variables in this scope */
1120 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1121 {
1122         struct local_vars_finder *vf = data;
1123         struct probe_finder *pf = vf->pf;
1124         int tag;
1125
1126         tag = dwarf_tag(die_mem);
1127         if (tag == DW_TAG_formal_parameter ||
1128             (tag == DW_TAG_variable && vf->vars)) {
1129                 if (convert_variable_location(die_mem, vf->pf->addr,
1130                                               vf->pf->fb_ops, &pf->sp_die,
1131                                               NULL) == 0) {
1132                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1133                         if (vf->args[vf->nargs].var == NULL) {
1134                                 vf->ret = -ENOMEM;
1135                                 return DIE_FIND_CB_END;
1136                         }
1137                         pr_debug(" %s", vf->args[vf->nargs].var);
1138                         vf->nargs++;
1139                 }
1140         }
1141
1142         if (dwarf_haspc(die_mem, vf->pf->addr))
1143                 return DIE_FIND_CB_CONTINUE;
1144         else
1145                 return DIE_FIND_CB_SIBLING;
1146 }
1147
1148 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1149                              struct perf_probe_arg *args)
1150 {
1151         Dwarf_Die die_mem;
1152         int i;
1153         int n = 0;
1154         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1155                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1156
1157         for (i = 0; i < pf->pev->nargs; i++) {
1158                 /* var never be NULL */
1159                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1160                         vf.vars = true;
1161                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1162                         /* Copy normal argument */
1163                         args[n] = pf->pev->args[i];
1164                         n++;
1165                         continue;
1166                 }
1167                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1168                 vf.nargs = n;
1169                 /* Special local variables */
1170                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1171                                &die_mem);
1172                 pr_debug(" (%d)\n", vf.nargs - n);
1173                 if (vf.ret < 0)
1174                         return vf.ret;
1175                 n = vf.nargs;
1176         }
1177         return n;
1178 }
1179
1180 /* Add a found probe point into trace event list */
1181 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1182 {
1183         struct trace_event_finder *tf =
1184                         container_of(pf, struct trace_event_finder, pf);
1185         struct probe_trace_event *tev;
1186         struct perf_probe_arg *args;
1187         int ret, i;
1188
1189         /* Check number of tevs */
1190         if (tf->ntevs == tf->max_tevs) {
1191                 pr_warning("Too many( > %d) probe point found.\n",
1192                            tf->max_tevs);
1193                 return -ERANGE;
1194         }
1195         tev = &tf->tevs[tf->ntevs++];
1196
1197         /* Trace point should be converted from subprogram DIE */
1198         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1199                                      pf->pev->point.retprobe, &tev->point);
1200         if (ret < 0)
1201                 return ret;
1202
1203         tev->point.realname = strdup(dwarf_diename(sc_die));
1204         if (!tev->point.realname)
1205                 return -ENOMEM;
1206
1207         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1208                  tev->point.offset);
1209
1210         /* Expand special probe argument if exist */
1211         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1212         if (args == NULL)
1213                 return -ENOMEM;
1214
1215         ret = expand_probe_args(sc_die, pf, args);
1216         if (ret < 0)
1217                 goto end;
1218
1219         tev->nargs = ret;
1220         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1221         if (tev->args == NULL) {
1222                 ret = -ENOMEM;
1223                 goto end;
1224         }
1225
1226         /* Find each argument */
1227         for (i = 0; i < tev->nargs; i++) {
1228                 pf->pvar = &args[i];
1229                 pf->tvar = &tev->args[i];
1230                 /* Variable should be found from scope DIE */
1231                 ret = find_variable(sc_die, pf);
1232                 if (ret != 0)
1233                         break;
1234         }
1235
1236 end:
1237         free(args);
1238         return ret;
1239 }
1240
1241 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1242 int debuginfo__find_trace_events(struct debuginfo *dbg,
1243                                  struct perf_probe_event *pev,
1244                                  struct probe_trace_event **tevs)
1245 {
1246         struct trace_event_finder tf = {
1247                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1248                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1249         int ret;
1250
1251         /* Allocate result tevs array */
1252         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1253         if (*tevs == NULL)
1254                 return -ENOMEM;
1255
1256         tf.tevs = *tevs;
1257         tf.ntevs = 0;
1258
1259         ret = debuginfo__find_probes(dbg, &tf.pf);
1260         if (ret < 0) {
1261                 zfree(tevs);
1262                 return ret;
1263         }
1264
1265         return (ret < 0) ? ret : tf.ntevs;
1266 }
1267
1268 /* Collect available variables in this scope */
1269 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1270 {
1271         struct available_var_finder *af = data;
1272         struct variable_list *vl;
1273         int tag, ret;
1274
1275         vl = &af->vls[af->nvls - 1];
1276
1277         tag = dwarf_tag(die_mem);
1278         if (tag == DW_TAG_formal_parameter ||
1279             tag == DW_TAG_variable) {
1280                 ret = convert_variable_location(die_mem, af->pf.addr,
1281                                                 af->pf.fb_ops, &af->pf.sp_die,
1282                                                 NULL);
1283                 if (ret == 0 || ret == -ERANGE) {
1284                         int ret2;
1285                         bool externs = !af->child;
1286                         struct strbuf buf;
1287
1288                         strbuf_init(&buf, 64);
1289
1290                         if (probe_conf.show_location_range) {
1291                                 if (!externs) {
1292                                         if (ret)
1293                                                 strbuf_addf(&buf, "[INV]\t");
1294                                         else
1295                                                 strbuf_addf(&buf, "[VAL]\t");
1296                                 } else
1297                                         strbuf_addf(&buf, "[EXT]\t");
1298                         }
1299
1300                         ret2 = die_get_varname(die_mem, &buf);
1301
1302                         if (!ret2 && probe_conf.show_location_range &&
1303                                 !externs) {
1304                                 strbuf_addf(&buf, "\t");
1305                                 ret2 = die_get_var_range(&af->pf.sp_die,
1306                                                         die_mem, &buf);
1307                         }
1308
1309                         pr_debug("Add new var: %s\n", buf.buf);
1310                         if (ret2 == 0) {
1311                                 strlist__add(vl->vars,
1312                                         strbuf_detach(&buf, NULL));
1313                         }
1314                         strbuf_release(&buf);
1315                 }
1316         }
1317
1318         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1319                 return DIE_FIND_CB_CONTINUE;
1320         else
1321                 return DIE_FIND_CB_SIBLING;
1322 }
1323
1324 /* Add a found vars into available variables list */
1325 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1326 {
1327         struct available_var_finder *af =
1328                         container_of(pf, struct available_var_finder, pf);
1329         struct variable_list *vl;
1330         Dwarf_Die die_mem;
1331         int ret;
1332
1333         /* Check number of tevs */
1334         if (af->nvls == af->max_vls) {
1335                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1336                 return -ERANGE;
1337         }
1338         vl = &af->vls[af->nvls++];
1339
1340         /* Trace point should be converted from subprogram DIE */
1341         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1342                                      pf->pev->point.retprobe, &vl->point);
1343         if (ret < 0)
1344                 return ret;
1345
1346         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1347                  vl->point.offset);
1348
1349         /* Find local variables */
1350         vl->vars = strlist__new(true, NULL);
1351         if (vl->vars == NULL)
1352                 return -ENOMEM;
1353         af->child = true;
1354         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1355
1356         /* Find external variables */
1357         if (!probe_conf.show_ext_vars)
1358                 goto out;
1359         /* Don't need to search child DIE for external vars. */
1360         af->child = false;
1361         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1362
1363 out:
1364         if (strlist__empty(vl->vars)) {
1365                 strlist__delete(vl->vars);
1366                 vl->vars = NULL;
1367         }
1368
1369         return ret;
1370 }
1371
1372 /*
1373  * Find available variables at given probe point
1374  * Return the number of found probe points. Return 0 if there is no
1375  * matched probe point. Return <0 if an error occurs.
1376  */
1377 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1378                                       struct perf_probe_event *pev,
1379                                       struct variable_list **vls)
1380 {
1381         struct available_var_finder af = {
1382                         .pf = {.pev = pev, .callback = add_available_vars},
1383                         .mod = dbg->mod,
1384                         .max_vls = probe_conf.max_probes};
1385         int ret;
1386
1387         /* Allocate result vls array */
1388         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1389         if (*vls == NULL)
1390                 return -ENOMEM;
1391
1392         af.vls = *vls;
1393         af.nvls = 0;
1394
1395         ret = debuginfo__find_probes(dbg, &af.pf);
1396         if (ret < 0) {
1397                 /* Free vlist for error */
1398                 while (af.nvls--) {
1399                         zfree(&af.vls[af.nvls].point.symbol);
1400                         strlist__delete(af.vls[af.nvls].vars);
1401                 }
1402                 zfree(vls);
1403                 return ret;
1404         }
1405
1406         return (ret < 0) ? ret : af.nvls;
1407 }
1408
1409 /* Reverse search */
1410 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1411                                 struct perf_probe_point *ppt)
1412 {
1413         Dwarf_Die cudie, spdie, indie;
1414         Dwarf_Addr _addr = 0, baseaddr = 0;
1415         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1416         int baseline = 0, lineno = 0, ret = 0;
1417
1418         /* Find cu die */
1419         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1420                 pr_warning("Failed to find debug information for address %lx\n",
1421                            addr);
1422                 ret = -EINVAL;
1423                 goto end;
1424         }
1425
1426         /* Find a corresponding line (filename and lineno) */
1427         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1428         /* Don't care whether it failed or not */
1429
1430         /* Find a corresponding function (name, baseline and baseaddr) */
1431         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1432                 /* Get function entry information */
1433                 func = basefunc = dwarf_diename(&spdie);
1434                 if (!func ||
1435                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1436                     dwarf_decl_line(&spdie, &baseline) != 0) {
1437                         lineno = 0;
1438                         goto post;
1439                 }
1440
1441                 fname = dwarf_decl_file(&spdie);
1442                 if (addr == (unsigned long)baseaddr) {
1443                         /* Function entry - Relative line number is 0 */
1444                         lineno = baseline;
1445                         goto post;
1446                 }
1447
1448                 /* Track down the inline functions step by step */
1449                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1450                                                 &indie)) {
1451                         /* There is an inline function */
1452                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1453                             _addr == addr) {
1454                                 /*
1455                                  * addr is at an inline function entry.
1456                                  * In this case, lineno should be the call-site
1457                                  * line number. (overwrite lineinfo)
1458                                  */
1459                                 lineno = die_get_call_lineno(&indie);
1460                                 fname = die_get_call_file(&indie);
1461                                 break;
1462                         } else {
1463                                 /*
1464                                  * addr is in an inline function body.
1465                                  * Since lineno points one of the lines
1466                                  * of the inline function, baseline should
1467                                  * be the entry line of the inline function.
1468                                  */
1469                                 tmp = dwarf_diename(&indie);
1470                                 if (!tmp ||
1471                                     dwarf_decl_line(&indie, &baseline) != 0)
1472                                         break;
1473                                 func = tmp;
1474                                 spdie = indie;
1475                         }
1476                 }
1477                 /* Verify the lineno and baseline are in a same file */
1478                 tmp = dwarf_decl_file(&spdie);
1479                 if (!tmp || strcmp(tmp, fname) != 0)
1480                         lineno = 0;
1481         }
1482
1483 post:
1484         /* Make a relative line number or an offset */
1485         if (lineno)
1486                 ppt->line = lineno - baseline;
1487         else if (basefunc) {
1488                 ppt->offset = addr - (unsigned long)baseaddr;
1489                 func = basefunc;
1490         }
1491
1492         /* Duplicate strings */
1493         if (func) {
1494                 ppt->function = strdup(func);
1495                 if (ppt->function == NULL) {
1496                         ret = -ENOMEM;
1497                         goto end;
1498                 }
1499         }
1500         if (fname) {
1501                 ppt->file = strdup(fname);
1502                 if (ppt->file == NULL) {
1503                         zfree(&ppt->function);
1504                         ret = -ENOMEM;
1505                         goto end;
1506                 }
1507         }
1508 end:
1509         if (ret == 0 && (fname || func))
1510                 ret = 1;        /* Found a point */
1511         return ret;
1512 }
1513
1514 /* Add a line and store the src path */
1515 static int line_range_add_line(const char *src, unsigned int lineno,
1516                                struct line_range *lr)
1517 {
1518         /* Copy source path */
1519         if (!lr->path) {
1520                 lr->path = strdup(src);
1521                 if (lr->path == NULL)
1522                         return -ENOMEM;
1523         }
1524         return intlist__add(lr->line_list, lineno);
1525 }
1526
1527 static int line_range_walk_cb(const char *fname, int lineno,
1528                               Dwarf_Addr addr __maybe_unused,
1529                               void *data)
1530 {
1531         struct line_finder *lf = data;
1532         int err;
1533
1534         if ((strtailcmp(fname, lf->fname) != 0) ||
1535             (lf->lno_s > lineno || lf->lno_e < lineno))
1536                 return 0;
1537
1538         err = line_range_add_line(fname, lineno, lf->lr);
1539         if (err < 0 && err != -EEXIST)
1540                 return err;
1541
1542         return 0;
1543 }
1544
1545 /* Find line range from its line number */
1546 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1547 {
1548         int ret;
1549
1550         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1551
1552         /* Update status */
1553         if (ret >= 0)
1554                 if (!intlist__empty(lf->lr->line_list))
1555                         ret = lf->found = 1;
1556                 else
1557                         ret = 0;        /* Lines are not found */
1558         else {
1559                 zfree(&lf->lr->path);
1560         }
1561         return ret;
1562 }
1563
1564 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1565 {
1566         int ret = find_line_range_by_line(in_die, data);
1567
1568         /*
1569          * We have to check all instances of inlined function, because
1570          * some execution paths can be optimized out depends on the
1571          * function argument of instances. However, if an error occurs,
1572          * it should be handled by the caller.
1573          */
1574         return ret < 0 ? ret : 0;
1575 }
1576
1577 /* Search function definition from function name */
1578 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1579 {
1580         struct dwarf_callback_param *param = data;
1581         struct line_finder *lf = param->data;
1582         struct line_range *lr = lf->lr;
1583
1584         /* Check declared file */
1585         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1586                 return DWARF_CB_OK;
1587
1588         if (die_is_func_def(sp_die) &&
1589             die_match_name(sp_die, lr->function)) {
1590                 lf->fname = dwarf_decl_file(sp_die);
1591                 dwarf_decl_line(sp_die, &lr->offset);
1592                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1593                 lf->lno_s = lr->offset + lr->start;
1594                 if (lf->lno_s < 0)      /* Overflow */
1595                         lf->lno_s = INT_MAX;
1596                 lf->lno_e = lr->offset + lr->end;
1597                 if (lf->lno_e < 0)      /* Overflow */
1598                         lf->lno_e = INT_MAX;
1599                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1600                 lr->start = lf->lno_s;
1601                 lr->end = lf->lno_e;
1602                 if (!die_is_func_instance(sp_die))
1603                         param->retval = die_walk_instances(sp_die,
1604                                                 line_range_inline_cb, lf);
1605                 else
1606                         param->retval = find_line_range_by_line(sp_die, lf);
1607                 return DWARF_CB_ABORT;
1608         }
1609         return DWARF_CB_OK;
1610 }
1611
1612 static int find_line_range_by_func(struct line_finder *lf)
1613 {
1614         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1615         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1616         return param.retval;
1617 }
1618
1619 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1620 {
1621         struct line_finder lf = {.lr = lr, .found = 0};
1622         int ret = 0;
1623         Dwarf_Off off = 0, noff;
1624         size_t cuhl;
1625         Dwarf_Die *diep;
1626         const char *comp_dir;
1627
1628         /* Fastpath: lookup by function name from .debug_pubnames section */
1629         if (lr->function) {
1630                 struct pubname_callback_param pubname_param = {
1631                         .function = lr->function, .file = lr->file,
1632                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1633                 struct dwarf_callback_param line_range_param = {
1634                         .data = (void *)&lf, .retval = 0};
1635
1636                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1637                                   &pubname_param, 0);
1638                 if (pubname_param.found) {
1639                         line_range_search_cb(&lf.sp_die, &line_range_param);
1640                         if (lf.found)
1641                                 goto found;
1642                 }
1643         }
1644
1645         /* Loop on CUs (Compilation Unit) */
1646         while (!lf.found && ret >= 0) {
1647                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1648                                  NULL, NULL, NULL) != 0)
1649                         break;
1650
1651                 /* Get the DIE(Debugging Information Entry) of this CU */
1652                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1653                 if (!diep)
1654                         continue;
1655
1656                 /* Check if target file is included. */
1657                 if (lr->file)
1658                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1659                 else
1660                         lf.fname = 0;
1661
1662                 if (!lr->file || lf.fname) {
1663                         if (lr->function)
1664                                 ret = find_line_range_by_func(&lf);
1665                         else {
1666                                 lf.lno_s = lr->start;
1667                                 lf.lno_e = lr->end;
1668                                 ret = find_line_range_by_line(NULL, &lf);
1669                         }
1670                 }
1671                 off = noff;
1672         }
1673
1674 found:
1675         /* Store comp_dir */
1676         if (lf.found) {
1677                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1678                 if (comp_dir) {
1679                         lr->comp_dir = strdup(comp_dir);
1680                         if (!lr->comp_dir)
1681                                 ret = -ENOMEM;
1682                 }
1683         }
1684
1685         pr_debug("path: %s\n", lr->path);
1686         return (ret < 0) ? ret : lf.found;
1687 }
1688
1689 /*
1690  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1691  * and chop off leading directories that do not exist. Result is passed back as
1692  * a newly allocated path on success.
1693  * Return 0 if file was found and readable, -errno otherwise.
1694  */
1695 int get_real_path(const char *raw_path, const char *comp_dir,
1696                          char **new_path)
1697 {
1698         const char *prefix = symbol_conf.source_prefix;
1699
1700         if (!prefix) {
1701                 if (raw_path[0] != '/' && comp_dir)
1702                         /* If not an absolute path, try to use comp_dir */
1703                         prefix = comp_dir;
1704                 else {
1705                         if (access(raw_path, R_OK) == 0) {
1706                                 *new_path = strdup(raw_path);
1707                                 return *new_path ? 0 : -ENOMEM;
1708                         } else
1709                                 return -errno;
1710                 }
1711         }
1712
1713         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1714         if (!*new_path)
1715                 return -ENOMEM;
1716
1717         for (;;) {
1718                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1719
1720                 if (access(*new_path, R_OK) == 0)
1721                         return 0;
1722
1723                 if (!symbol_conf.source_prefix) {
1724                         /* In case of searching comp_dir, don't retry */
1725                         zfree(new_path);
1726                         return -errno;
1727                 }
1728
1729                 switch (errno) {
1730                 case ENAMETOOLONG:
1731                 case ENOENT:
1732                 case EROFS:
1733                 case EFAULT:
1734                         raw_path = strchr(++raw_path, '/');
1735                         if (!raw_path) {
1736                                 zfree(new_path);
1737                                 return -ENOENT;
1738                         }
1739                         continue;
1740
1741                 default:
1742                         zfree(new_path);
1743                         return -errno;
1744                 }
1745         }
1746 }