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