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