tools/perf/util/probe-finder.c

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