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