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