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 #include "probe-file.h"
  43
  44 /* Kprobe tracer basic type is up to u64 */
  45 #define MAX_BASIC_TYPE_BITS     64
  46
  47 /* Dwarf FL wrappers */
  48 static char *debuginfo_path;    /* Currently dummy */
  49
  50 static const Dwfl_Callbacks offline_callbacks = {
  51         .find_debuginfo = dwfl_standard_find_debuginfo,
  52         .debuginfo_path = &debuginfo_path,
  53
  54         .section_address = dwfl_offline_section_address,
  55
  56         /* We use this table for core files too.  */
  57         .find_elf = dwfl_build_id_find_elf,
  58 };
  59
  60 /* Get a Dwarf from offline image */
  61 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  62                                          const char *path)
  63 {
  64         int fd;
  65
  66         fd = open(path, O_RDONLY);
  67         if (fd < 0)
  68                 return fd;
  69
  70         dbg->dwfl = dwfl_begin(&offline_callbacks);
  71         if (!dbg->dwfl)
  72                 goto error;
  73
  74         dwfl_report_begin(dbg->dwfl);
  75         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  76         if (!dbg->mod)
  77                 goto error;
  78
  79         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  80         if (!dbg->dbg)
  81                 goto error;
  82
  83         dwfl_report_end(dbg->dwfl, NULL, NULL);
  84
  85         return 0;
  86 error:
  87         if (dbg->dwfl)
  88                 dwfl_end(dbg->dwfl);
  89         else
  90                 close(fd);
  91         memset(dbg, 0, sizeof(*dbg));
  92
  93         return -ENOENT;
  94 }
  95
  96 static struct debuginfo *__debuginfo__new(const char *path)
  97 {
  98         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  99         if (!dbg)
 100                 return NULL;
 101
 102         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 103                 zfree(&dbg);
 104         if (dbg)
 105                 pr_debug("Open Debuginfo file: %s\n", path);
 106         return dbg;
 107 }
 108
 109 enum dso_binary_type distro_dwarf_types[] = {
 110         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 111         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 112         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 113         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 114         DSO_BINARY_TYPE__NOT_FOUND,
 115 };
 116
 117 struct debuginfo *debuginfo__new(const char *path)
 118 {
 119         enum dso_binary_type *type;
 120         char buf[PATH_MAX], nil = '\0';
 121         struct dso *dso;
 122         struct debuginfo *dinfo = NULL;
 123
 124         /* Try to open distro debuginfo files */
 125         dso = dso__new(path);
 126         if (!dso)
 127                 goto out;
 128
 129         for (type = distro_dwarf_types;
 130              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 131              type++) {
 132                 if (dso__read_binary_type_filename(dso, *type, &nil,
 133                                                    buf, PATH_MAX) < 0)
 134                         continue;
 135                 dinfo = __debuginfo__new(buf);
 136         }
 137         dso__put(dso);
 138
 139 out:
 140         /* if failed to open all distro debuginfo, open given binary */
 141         return dinfo ? : __debuginfo__new(path);
 142 }
 143
 144 void debuginfo__delete(struct debuginfo *dbg)
 145 {
 146         if (dbg) {
 147                 if (dbg->dwfl)
 148                         dwfl_end(dbg->dwfl);
 149                 free(dbg);
 150         }
 151 }
 152
 153 /*
 154  * Probe finder related functions
 155  */
 156
 157 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 158 {
 159         struct probe_trace_arg_ref *ref;
 160         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 161         if (ref != NULL)
 162                 ref->offset = offs;
 163         return ref;
 164 }
 165
 166 /*
 167  * Convert a location into trace_arg.
 168  * If tvar == NULL, this just checks variable can be converted.
 169  * If fentry == true and vr_die is a parameter, do huristic search
 170  * for the location fuzzed by function entry mcount.
 171  */
 172 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 173                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 174                                      struct probe_trace_arg *tvar)
 175 {
 176         Dwarf_Attribute attr;
 177         Dwarf_Addr tmp = 0;
 178         Dwarf_Op *op;
 179         size_t nops;
 180         unsigned int regn;
 181         Dwarf_Word offs = 0;
 182         bool ref = false;
 183         const char *regs;
 184         int ret, ret2 = 0;
 185
 186         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 187                 goto static_var;
 188
 189         /* TODO: handle more than 1 exprs */
 190         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 191                 return -EINVAL; /* Broken DIE ? */
 192         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 193                 ret = dwarf_entrypc(sp_die, &tmp);
 194                 if (ret)
 195                         return -ENOENT;
 196
 197                 if (probe_conf.show_location_range &&
 198                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 199                         ret2 = -ERANGE;
 200                 } else if (addr != tmp ||
 201                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 202                         return -ENOENT;
 203                 }
 204
 205                 ret = dwarf_highpc(sp_die, &tmp);
 206                 if (ret)
 207                         return -ENOENT;
 208                 /*
 209                  * This is fuzzed by fentry mcount. We try to find the
 210                  * parameter location at the earliest address.
 211                  */
 212                 for (addr += 1; addr <= tmp; addr++) {
 213                         if (dwarf_getlocation_addr(&attr, addr, &op,
 214                                                    &nops, 1) > 0)
 215                                 goto found;
 216                 }
 217                 return -ENOENT;
 218         }
 219 found:
 220         if (nops == 0)
 221                 /* TODO: Support const_value */
 222                 return -ENOENT;
 223
 224         if (op->atom == DW_OP_addr) {
 225 static_var:
 226                 if (!tvar)
 227                         return ret2;
 228                 /* Static variables on memory (not stack), make @varname */
 229                 ret = strlen(dwarf_diename(vr_die));
 230                 tvar->value = zalloc(ret + 2);
 231                 if (tvar->value == NULL)
 232                         return -ENOMEM;
 233                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 234                 tvar->ref = alloc_trace_arg_ref((long)offs);
 235                 if (tvar->ref == NULL)
 236                         return -ENOMEM;
 237                 return ret2;
 238         }
 239
 240         /* If this is based on frame buffer, set the offset */
 241         if (op->atom == DW_OP_fbreg) {
 242                 if (fb_ops == NULL)
 243                         return -ENOTSUP;
 244                 ref = true;
 245                 offs = op->number;
 246                 op = &fb_ops[0];
 247         }
 248
 249         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 250                 regn = op->atom - DW_OP_breg0;
 251                 offs += op->number;
 252                 ref = true;
 253         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 254                 regn = op->atom - DW_OP_reg0;
 255         } else if (op->atom == DW_OP_bregx) {
 256                 regn = op->number;
 257                 offs += op->number2;
 258                 ref = true;
 259         } else if (op->atom == DW_OP_regx) {
 260                 regn = op->number;
 261         } else {
 262                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 263                 return -ENOTSUP;
 264         }
 265
 266         if (!tvar)
 267                 return ret2;
 268
 269         regs = get_arch_regstr(regn);
 270         if (!regs) {
 271                 /* This should be a bug in DWARF or this tool */
 272                 pr_warning("Mapping for the register number %u "
 273                            "missing on this architecture.\n", regn);
 274                 return -ENOTSUP;
 275         }
 276
 277         tvar->value = strdup(regs);
 278         if (tvar->value == NULL)
 279                 return -ENOMEM;
 280
 281         if (ref) {
 282                 tvar->ref = alloc_trace_arg_ref((long)offs);
 283                 if (tvar->ref == NULL)
 284                         return -ENOMEM;
 285         }
 286         return ret2;
 287 }
 288
 289 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 290
 291 static int convert_variable_type(Dwarf_Die *vr_die,
 292                                  struct probe_trace_arg *tvar,
 293                                  const char *cast)
 294 {
 295         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 296         Dwarf_Die type;
 297         char buf[16];
 298         char sbuf[STRERR_BUFSIZE];
 299         int bsize, boffs, total;
 300         int ret;
 301         char sign;
 302
 303         /* TODO: check all types */
 304         if (cast && strcmp(cast, "string") != 0 &&
 305             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 306                 /* Non string type is OK */
 307                 /* and respect signedness cast */
 308                 tvar->type = strdup(cast);
 309                 return (tvar->type == NULL) ? -ENOMEM : 0;
 310         }
 311
 312         bsize = dwarf_bitsize(vr_die);
 313         if (bsize > 0) {
 314                 /* This is a bitfield */
 315                 boffs = dwarf_bitoffset(vr_die);
 316                 total = dwarf_bytesize(vr_die);
 317                 if (boffs < 0 || total < 0)
 318                         return -ENOENT;
 319                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 320                                 BYTES_TO_BITS(total));
 321                 goto formatted;
 322         }
 323
 324         if (die_get_real_type(vr_die, &type) == NULL) {
 325                 pr_warning("Failed to get a type information of %s.\n",
 326                            dwarf_diename(vr_die));
 327                 return -ENOENT;
 328         }
 329
 330         pr_debug("%s type is %s.\n",
 331                  dwarf_diename(vr_die), dwarf_diename(&type));
 332
 333         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 334                 ret = dwarf_tag(&type);
 335                 if (ret != DW_TAG_pointer_type &&
 336                     ret != DW_TAG_array_type) {
 337                         pr_warning("Failed to cast into string: "
 338                                    "%s(%s) is not a pointer nor array.\n",
 339                                    dwarf_diename(vr_die), dwarf_diename(&type));
 340                         return -EINVAL;
 341                 }
 342                 if (die_get_real_type(&type, &type) == NULL) {
 343                         pr_warning("Failed to get a type"
 344                                    " information.\n");
 345                         return -ENOENT;
 346                 }
 347                 if (ret == DW_TAG_pointer_type) {
 348                         while (*ref_ptr)
 349                                 ref_ptr = &(*ref_ptr)->next;
 350                         /* Add new reference with offset +0 */
 351                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 352                         if (*ref_ptr == NULL) {
 353                                 pr_warning("Out of memory error\n");
 354                                 return -ENOMEM;
 355                         }
 356                 }
 357                 if (!die_compare_name(&type, "char") &&
 358                     !die_compare_name(&type, "unsigned char")) {
 359                         pr_warning("Failed to cast into string: "
 360                                    "%s is not (unsigned) char *.\n",
 361                                    dwarf_diename(vr_die));
 362                         return -EINVAL;
 363                 }
 364                 tvar->type = strdup(cast);
 365                 return (tvar->type == NULL) ? -ENOMEM : 0;
 366         }
 367
 368         if (cast && (strcmp(cast, "u") == 0))
 369                 sign = 'u';
 370         else if (cast && (strcmp(cast, "s") == 0))
 371                 sign = 's';
 372         else
 373                 sign = die_is_signed_type(&type) ? 's' : 'u';
 374
 375         ret = dwarf_bytesize(&type);
 376         if (ret <= 0)
 377                 /* No size ... try to use default type */
 378                 return 0;
 379         ret = BYTES_TO_BITS(ret);
 380
 381         /* Check the bitwidth */
 382         if (ret > MAX_BASIC_TYPE_BITS) {
 383                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 384                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 385                 ret = MAX_BASIC_TYPE_BITS;
 386         }
 387         ret = snprintf(buf, 16, "%c%d", sign, ret);
 388
 389 formatted:
 390         if (ret < 0 || ret >= 16) {
 391                 if (ret >= 16)
 392                         ret = -E2BIG;
 393                 pr_warning("Failed to convert variable type: %s\n",
 394                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 395                 return ret;
 396         }
 397         tvar->type = strdup(buf);
 398         if (tvar->type == NULL)
 399                 return -ENOMEM;
 400         return 0;
 401 }
 402
 403 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 404                                     struct perf_probe_arg_field *field,
 405                                     struct probe_trace_arg_ref **ref_ptr,
 406                                     Dwarf_Die *die_mem)
 407 {
 408         struct probe_trace_arg_ref *ref = *ref_ptr;
 409         Dwarf_Die type;
 410         Dwarf_Word offs;
 411         int ret, tag;
 412
 413         pr_debug("converting %s in %s\n", field->name, varname);
 414         if (die_get_real_type(vr_die, &type) == NULL) {
 415                 pr_warning("Failed to get the type of %s.\n", varname);
 416                 return -ENOENT;
 417         }
 418         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 419         tag = dwarf_tag(&type);
 420
 421         if (field->name[0] == '[' &&
 422             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 423                 if (field->next)
 424                         /* Save original type for next field */
 425                         memcpy(die_mem, &type, sizeof(*die_mem));
 426                 /* Get the type of this array */
 427                 if (die_get_real_type(&type, &type) == NULL) {
 428                         pr_warning("Failed to get the type of %s.\n", varname);
 429                         return -ENOENT;
 430                 }
 431                 pr_debug2("Array real type: (%x)\n",
 432                          (unsigned)dwarf_dieoffset(&type));
 433                 if (tag == DW_TAG_pointer_type) {
 434                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 435                         if (ref == NULL)
 436                                 return -ENOMEM;
 437                         if (*ref_ptr)
 438                                 (*ref_ptr)->next = ref;
 439                         else
 440                                 *ref_ptr = ref;
 441                 }
 442                 ref->offset += dwarf_bytesize(&type) * field->index;
 443                 if (!field->next)
 444                         /* Save vr_die for converting types */
 445                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 446                 goto next;
 447         } else if (tag == DW_TAG_pointer_type) {
 448                 /* Check the pointer and dereference */
 449                 if (!field->ref) {
 450                         pr_err("Semantic error: %s must be referred by '->'\n",
 451                                field->name);
 452                         return -EINVAL;
 453                 }
 454                 /* Get the type pointed by this pointer */
 455                 if (die_get_real_type(&type, &type) == NULL) {
 456                         pr_warning("Failed to get the type of %s.\n", varname);
 457                         return -ENOENT;
 458                 }
 459                 /* Verify it is a data structure  */
 460                 tag = dwarf_tag(&type);
 461                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 462                         pr_warning("%s is not a data structure nor an union.\n",
 463                                    varname);
 464                         return -EINVAL;
 465                 }
 466
 467                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 468                 if (ref == NULL)
 469                         return -ENOMEM;
 470                 if (*ref_ptr)
 471                         (*ref_ptr)->next = ref;
 472                 else
 473                         *ref_ptr = ref;
 474         } else {
 475                 /* Verify it is a data structure  */
 476                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 477                         pr_warning("%s is not a data structure nor an union.\n",
 478                                    varname);
 479                         return -EINVAL;
 480                 }
 481                 if (field->name[0] == '[') {
 482                         pr_err("Semantic error: %s is not a pointer"
 483                                " nor array.\n", varname);
 484                         return -EINVAL;
 485                 }
 486                 /* While prcessing unnamed field, we don't care about this */
 487                 if (field->ref && dwarf_diename(vr_die)) {
 488                         pr_err("Semantic error: %s must be referred by '.'\n",
 489                                field->name);
 490                         return -EINVAL;
 491                 }
 492                 if (!ref) {
 493                         pr_warning("Structure on a register is not "
 494                                    "supported yet.\n");
 495                         return -ENOTSUP;
 496                 }
 497         }
 498
 499         if (die_find_member(&type, field->name, die_mem) == NULL) {
 500                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 501                            dwarf_diename(&type), field->name);
 502                 return -EINVAL;
 503         }
 504
 505         /* Get the offset of the field */
 506         if (tag == DW_TAG_union_type) {
 507                 offs = 0;
 508         } else {
 509                 ret = die_get_data_member_location(die_mem, &offs);
 510                 if (ret < 0) {
 511                         pr_warning("Failed to get the offset of %s.\n",
 512                                    field->name);
 513                         return ret;
 514                 }
 515         }
 516         ref->offset += (long)offs;
 517
 518         /* If this member is unnamed, we need to reuse this field */
 519         if (!dwarf_diename(die_mem))
 520                 return convert_variable_fields(die_mem, varname, field,
 521                                                 &ref, die_mem);
 522
 523 next:
 524         /* Converting next field */
 525         if (field->next)
 526                 return convert_variable_fields(die_mem, field->name,
 527                                         field->next, &ref, die_mem);
 528         else
 529                 return 0;
 530 }
 531
 532 /* Show a variables in kprobe event format */
 533 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 534 {
 535         Dwarf_Die die_mem;
 536         int ret;
 537
 538         pr_debug("Converting variable %s into trace event.\n",
 539                  dwarf_diename(vr_die));
 540
 541         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 542                                         &pf->sp_die, pf->tvar);
 543         if (ret == -ENOENT || ret == -EINVAL) {
 544                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 545                        " Perhaps it has been optimized out.\n"
 546                        " Use -V with the --range option to show '%s' location range.\n",
 547                        pf->pvar->var, pf->pvar->var);
 548         } else if (ret == -ENOTSUP)
 549                 pr_err("Sorry, we don't support this variable location yet.\n");
 550         else if (ret == 0 && pf->pvar->field) {
 551                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 552                                               pf->pvar->field, &pf->tvar->ref,
 553                                               &die_mem);
 554                 vr_die = &die_mem;
 555         }
 556         if (ret == 0)
 557                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 558         /* *expr will be cached in libdw. Don't free it. */
 559         return ret;
 560 }
 561
 562 /* Find a variable in a scope DIE */
 563 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 564 {
 565         Dwarf_Die vr_die;
 566         char *buf, *ptr;
 567         int ret = 0;
 568
 569         /* Copy raw parameters */
 570         if (!is_c_varname(pf->pvar->var))
 571                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 572
 573         if (pf->pvar->name)
 574                 pf->tvar->name = strdup(pf->pvar->name);
 575         else {
 576                 buf = synthesize_perf_probe_arg(pf->pvar);
 577                 if (!buf)
 578                         return -ENOMEM;
 579                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 580                 if (ptr)
 581                         *ptr = '_';
 582                 pf->tvar->name = buf;
 583         }
 584         if (pf->tvar->name == NULL)
 585                 return -ENOMEM;
 586
 587         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 588         /* Search child die for local variables and parameters. */
 589         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 590                 /* Search again in global variables */
 591                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 592                                                 0, &vr_die)) {
 593                         pr_warning("Failed to find '%s' in this function.\n",
 594                                    pf->pvar->var);
 595                         ret = -ENOENT;
 596                 }
 597         }
 598         if (ret >= 0)
 599                 ret = convert_variable(&vr_die, pf);
 600
 601         return ret;
 602 }
 603
 604 /* Convert subprogram DIE to trace point */
 605 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 606                                   Dwarf_Addr paddr, bool retprobe,
 607                                   const char *function,
 608                                   struct probe_trace_point *tp)
 609 {
 610         Dwarf_Addr eaddr, highaddr;
 611         GElf_Sym sym;
 612         const char *symbol;
 613
 614         /* Verify the address is correct */
 615         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 616                 pr_warning("Failed to get entry address of %s\n",
 617                            dwarf_diename(sp_die));
 618                 return -ENOENT;
 619         }
 620         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 621                 pr_warning("Failed to get end address of %s\n",
 622                            dwarf_diename(sp_die));
 623                 return -ENOENT;
 624         }
 625         if (paddr > highaddr) {
 626                 pr_warning("Offset specified is greater than size of %s\n",
 627                            dwarf_diename(sp_die));
 628                 return -EINVAL;
 629         }
 630
 631         symbol = dwarf_diename(sp_die);
 632         if (!symbol) {
 633                 /* Try to get the symbol name from symtab */
 634                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 635                 if (!symbol) {
 636                         pr_warning("Failed to find symbol at 0x%lx\n",
 637                                    (unsigned long)paddr);
 638                         return -ENOENT;
 639                 }
 640                 eaddr = sym.st_value;
 641         }
 642         tp->offset = (unsigned long)(paddr - eaddr);
 643         tp->address = (unsigned long)paddr;
 644         tp->symbol = strdup(symbol);
 645         if (!tp->symbol)
 646                 return -ENOMEM;
 647
 648         /* Return probe must be on the head of a subprogram */
 649         if (retprobe) {
 650                 if (eaddr != paddr) {
 651                         pr_warning("Failed to find \"%s%%return\",\n"
 652                                    " because %s is an inlined function and"
 653                                    " has no return point.\n", function,
 654                                    function);
 655                         return -EINVAL;
 656                 }
 657                 tp->retprobe = true;
 658         }
 659
 660         return 0;
 661 }
 662
 663 /* Call probe_finder callback with scope DIE */
 664 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 665 {
 666         Dwarf_Attribute fb_attr;
 667         Dwarf_Frame *frame = NULL;
 668         size_t nops;
 669         int ret;
 670
 671         if (!sc_die) {
 672                 pr_err("Caller must pass a scope DIE. Program error.\n");
 673                 return -EINVAL;
 674         }
 675
 676         /* If not a real subprogram, find a real one */
 677         if (!die_is_func_def(sc_die)) {
 678                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 679                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 680                                 pr_warning("Ignoring tail call from %s\n",
 681                                                 dwarf_diename(&pf->sp_die));
 682                                 return 0;
 683                         } else {
 684                                 pr_warning("Failed to find probe point in any "
 685                                            "functions.\n");
 686                                 return -ENOENT;
 687                         }
 688                 }
 689         } else
 690                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 691
 692         /* Get the frame base attribute/ops from subprogram */
 693         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 694         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 695         if (ret <= 0 || nops == 0) {
 696                 pf->fb_ops = NULL;
 697 #if _ELFUTILS_PREREQ(0, 142)
 698         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 699                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 700                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 701                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 702                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 703                         pr_warning("Failed to get call frame on 0x%jx\n",
 704                                    (uintmax_t)pf->addr);
 705                         free(frame);
 706                         return -ENOENT;
 707                 }
 708 #endif
 709         }
 710
 711         /* Call finder's callback handler */
 712         ret = pf->callback(sc_die, pf);
 713
 714         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 715         free(frame);
 716         pf->fb_ops = NULL;
 717
 718         return ret;
 719 }
 720
 721 struct find_scope_param {
 722         const char *function;
 723         const char *file;
 724         int line;
 725         int diff;
 726         Dwarf_Die *die_mem;
 727         bool found;
 728 };
 729
 730 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 731 {
 732         struct find_scope_param *fsp = data;
 733         const char *file;
 734         int lno;
 735
 736         /* Skip if declared file name does not match */
 737         if (fsp->file) {
 738                 file = dwarf_decl_file(fn_die);
 739                 if (!file || strcmp(fsp->file, file) != 0)
 740                         return 0;
 741         }
 742         /* If the function name is given, that's what user expects */
 743         if (fsp->function) {
 744                 if (die_match_name(fn_die, fsp->function)) {
 745                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 746                         fsp->found = true;
 747                         return 1;
 748                 }
 749         } else {
 750                 /* With the line number, find the nearest declared DIE */
 751                 dwarf_decl_line(fn_die, &lno);
 752                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 753                         /* Keep a candidate and continue */
 754                         fsp->diff = fsp->line - lno;
 755                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 756                         fsp->found = true;
 757                 }
 758         }
 759         return 0;
 760 }
 761
 762 /* Find an appropriate scope fits to given conditions */
 763 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 764 {
 765         struct find_scope_param fsp = {
 766                 .function = pf->pev->point.function,
 767                 .file = pf->fname,
 768                 .line = pf->lno,
 769                 .diff = INT_MAX,
 770                 .die_mem = die_mem,
 771                 .found = false,
 772         };
 773
 774         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 775
 776         return fsp.found ? die_mem : NULL;
 777 }
 778
 779 static int probe_point_line_walker(const char *fname, int lineno,
 780                                    Dwarf_Addr addr, void *data)
 781 {
 782         struct probe_finder *pf = data;
 783         Dwarf_Die *sc_die, die_mem;
 784         int ret;
 785
 786         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 787                 return 0;
 788
 789         pf->addr = addr;
 790         sc_die = find_best_scope(pf, &die_mem);
 791         if (!sc_die) {
 792                 pr_warning("Failed to find scope of probe point.\n");
 793                 return -ENOENT;
 794         }
 795
 796         ret = call_probe_finder(sc_die, pf);
 797
 798         /* Continue if no error, because the line will be in inline function */
 799         return ret < 0 ? ret : 0;
 800 }
 801
 802 /* Find probe point from its line number */
 803 static int find_probe_point_by_line(struct probe_finder *pf)
 804 {
 805         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 806 }
 807
 808 /* Find lines which match lazy pattern */
 809 static int find_lazy_match_lines(struct intlist *list,
 810                                  const char *fname, const char *pat)
 811 {
 812         FILE *fp;
 813         char *line = NULL;
 814         size_t line_len;
 815         ssize_t len;
 816         int count = 0, linenum = 1;
 817         char sbuf[STRERR_BUFSIZE];
 818
 819         fp = fopen(fname, "r");
 820         if (!fp) {
 821                 pr_warning("Failed to open %s: %s\n", fname,
 822                            str_error_r(errno, sbuf, sizeof(sbuf)));
 823                 return -errno;
 824         }
 825
 826         while ((len = getline(&line, &line_len, fp)) > 0) {
 827
 828                 if (line[len - 1] == '\n')
 829                         line[len - 1] = '\0';
 830
 831                 if (strlazymatch(line, pat)) {
 832                         intlist__add(list, linenum);
 833                         count++;
 834                 }
 835                 linenum++;
 836         }
 837
 838         if (ferror(fp))
 839                 count = -errno;
 840         free(line);
 841         fclose(fp);
 842
 843         if (count == 0)
 844                 pr_debug("No matched lines found in %s.\n", fname);
 845         return count;
 846 }
 847
 848 static int probe_point_lazy_walker(const char *fname, int lineno,
 849                                    Dwarf_Addr addr, void *data)
 850 {
 851         struct probe_finder *pf = data;
 852         Dwarf_Die *sc_die, die_mem;
 853         int ret;
 854
 855         if (!intlist__has_entry(pf->lcache, lineno) ||
 856             strtailcmp(fname, pf->fname) != 0)
 857                 return 0;
 858
 859         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 860                  lineno, (unsigned long long)addr);
 861         pf->addr = addr;
 862         pf->lno = lineno;
 863         sc_die = find_best_scope(pf, &die_mem);
 864         if (!sc_die) {
 865                 pr_warning("Failed to find scope of probe point.\n");
 866                 return -ENOENT;
 867         }
 868
 869         ret = call_probe_finder(sc_die, pf);
 870
 871         /*
 872          * Continue if no error, because the lazy pattern will match
 873          * to other lines
 874          */
 875         return ret < 0 ? ret : 0;
 876 }
 877
 878 /* Find probe points from lazy pattern  */
 879 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 880 {
 881         int ret = 0;
 882         char *fpath;
 883
 884         if (intlist__empty(pf->lcache)) {
 885                 const char *comp_dir;
 886
 887                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 888                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 889                 if (ret < 0) {
 890                         pr_warning("Failed to find source file path.\n");
 891                         return ret;
 892                 }
 893
 894                 /* Matching lazy line pattern */
 895                 ret = find_lazy_match_lines(pf->lcache, fpath,
 896                                             pf->pev->point.lazy_line);
 897                 free(fpath);
 898                 if (ret <= 0)
 899                         return ret;
 900         }
 901
 902         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 903 }
 904
 905 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 906 {
 907         struct probe_finder *pf = data;
 908         struct perf_probe_point *pp = &pf->pev->point;
 909         Dwarf_Addr addr;
 910         int ret;
 911
 912         if (pp->lazy_line)
 913                 ret = find_probe_point_lazy(in_die, pf);
 914         else {
 915                 /* Get probe address */
 916                 if (dwarf_entrypc(in_die, &addr) != 0) {
 917                         pr_warning("Failed to get entry address of %s.\n",
 918                                    dwarf_diename(in_die));
 919                         return -ENOENT;
 920                 }
 921                 pf->addr = addr;
 922                 pf->addr += pp->offset;
 923                 pr_debug("found inline addr: 0x%jx\n",
 924                          (uintmax_t)pf->addr);
 925
 926                 ret = call_probe_finder(in_die, pf);
 927         }
 928
 929         return ret;
 930 }
 931
 932 /* Callback parameter with return value for libdw */
 933 struct dwarf_callback_param {
 934         void *data;
 935         int retval;
 936 };
 937
 938 /* Search function from function name */
 939 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 940 {
 941         struct dwarf_callback_param *param = data;
 942         struct probe_finder *pf = param->data;
 943         struct perf_probe_point *pp = &pf->pev->point;
 944
 945         /* Check tag and diename */
 946         if (!die_is_func_def(sp_die) ||
 947             !die_match_name(sp_die, pp->function))
 948                 return DWARF_CB_OK;
 949
 950         /* Check declared file */
 951         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 952                 return DWARF_CB_OK;
 953
 954         pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
 955         pf->fname = dwarf_decl_file(sp_die);
 956         if (pp->line) { /* Function relative line */
 957                 dwarf_decl_line(sp_die, &pf->lno);
 958                 pf->lno += pp->line;
 959                 param->retval = find_probe_point_by_line(pf);
 960         } else if (die_is_func_instance(sp_die)) {
 961                 /* Instances always have the entry address */
 962                 dwarf_entrypc(sp_die, &pf->addr);
 963                 /* Real function */
 964                 if (pp->lazy_line)
 965                         param->retval = find_probe_point_lazy(sp_die, pf);
 966                 else {
 967                         pf->addr += pp->offset;
 968                         /* TODO: Check the address in this function */
 969                         param->retval = call_probe_finder(sp_die, pf);
 970                 }
 971         } else if (!probe_conf.no_inlines) {
 972                 /* Inlined function: search instances */
 973                 param->retval = die_walk_instances(sp_die,
 974                                         probe_point_inline_cb, (void *)pf);
 975                 /* This could be a non-existed inline definition */
 976                 if (param->retval == -ENOENT && strisglob(pp->function))
 977                         param->retval = 0;
 978         }
 979
 980         /* We need to find other candidates */
 981         if (strisglob(pp->function) && param->retval >= 0) {
 982                 param->retval = 0;      /* We have to clear the result */
 983                 return DWARF_CB_OK;
 984         }
 985
 986         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 987 }
 988
 989 static int find_probe_point_by_func(struct probe_finder *pf)
 990 {
 991         struct dwarf_callback_param _param = {.data = (void *)pf,
 992                                               .retval = 0};
 993         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 994         return _param.retval;
 995 }
 996
 997 struct pubname_callback_param {
 998         char *function;
 999         char *file;
1000         Dwarf_Die *cu_die;
1001         Dwarf_Die *sp_die;
1002         int found;
1003 };
1004
1005 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1006 {
1007         struct pubname_callback_param *param = data;
1008
1009         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1010                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1011                         return DWARF_CB_OK;
1012
1013                 if (die_match_name(param->sp_die, param->function)) {
1014                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1015                                 return DWARF_CB_OK;
1016
1017                         if (param->file &&
1018                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1019                                 return DWARF_CB_OK;
1020
1021                         param->found = 1;
1022                         return DWARF_CB_ABORT;
1023                 }
1024         }
1025
1026         return DWARF_CB_OK;
1027 }
1028
1029 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1030                                   struct probe_finder *pf)
1031 {
1032         struct perf_probe_point *pp = &pf->pev->point;
1033         Dwarf_Off off, noff;
1034         size_t cuhl;
1035         Dwarf_Die *diep;
1036         int ret = 0;
1037
1038         off = 0;
1039         pf->lcache = intlist__new(NULL);
1040         if (!pf->lcache)
1041                 return -ENOMEM;
1042
1043         /* Fastpath: lookup by function name from .debug_pubnames section */
1044         if (pp->function && !strisglob(pp->function)) {
1045                 struct pubname_callback_param pubname_param = {
1046                         .function = pp->function,
1047                         .file     = pp->file,
1048                         .cu_die   = &pf->cu_die,
1049                         .sp_die   = &pf->sp_die,
1050                         .found    = 0,
1051                 };
1052                 struct dwarf_callback_param probe_param = {
1053                         .data = pf,
1054                 };
1055
1056                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1057                                   &pubname_param, 0);
1058                 if (pubname_param.found) {
1059                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1060                         if (ret)
1061                                 goto found;
1062                 }
1063         }
1064
1065         /* Loop on CUs (Compilation Unit) */
1066         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1067                 /* Get the DIE(Debugging Information Entry) of this CU */
1068                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1069                 if (!diep)
1070                         continue;
1071
1072                 /* Check if target file is included. */
1073                 if (pp->file)
1074                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1075                 else
1076                         pf->fname = NULL;
1077
1078                 if (!pp->file || pf->fname) {
1079                         if (pp->function)
1080                                 ret = find_probe_point_by_func(pf);
1081                         else if (pp->lazy_line)
1082                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1083                         else {
1084                                 pf->lno = pp->line;
1085                                 ret = find_probe_point_by_line(pf);
1086                         }
1087                         if (ret < 0)
1088                                 break;
1089                 }
1090                 off = noff;
1091         }
1092
1093 found:
1094         intlist__delete(pf->lcache);
1095         pf->lcache = NULL;
1096
1097         return ret;
1098 }
1099
1100 /* Find probe points from debuginfo */
1101 static int debuginfo__find_probes(struct debuginfo *dbg,
1102                                   struct probe_finder *pf)
1103 {
1104         int ret = 0;
1105
1106 #if _ELFUTILS_PREREQ(0, 142)
1107         Elf *elf;
1108         GElf_Ehdr ehdr;
1109         GElf_Shdr shdr;
1110
1111         if (pf->cfi_eh || pf->cfi_dbg)
1112                 return debuginfo__find_probe_location(dbg, pf);
1113
1114         /* Get the call frame information from this dwarf */
1115         elf = dwarf_getelf(dbg->dbg);
1116         if (elf == NULL)
1117                 return -EINVAL;
1118
1119         if (gelf_getehdr(elf, &ehdr) == NULL)
1120                 return -EINVAL;
1121
1122         if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1123             shdr.sh_type == SHT_PROGBITS)
1124                 pf->cfi_eh = dwarf_getcfi_elf(elf);
1125
1126         pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1127 #endif
1128
1129         ret = debuginfo__find_probe_location(dbg, pf);
1130         return ret;
1131 }
1132
1133 struct local_vars_finder {
1134         struct probe_finder *pf;
1135         struct perf_probe_arg *args;
1136         bool vars;
1137         int max_args;
1138         int nargs;
1139         int ret;
1140 };
1141
1142 /* Collect available variables in this scope */
1143 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1144 {
1145         struct local_vars_finder *vf = data;
1146         struct probe_finder *pf = vf->pf;
1147         int tag;
1148
1149         tag = dwarf_tag(die_mem);
1150         if (tag == DW_TAG_formal_parameter ||
1151             (tag == DW_TAG_variable && vf->vars)) {
1152                 if (convert_variable_location(die_mem, vf->pf->addr,
1153                                               vf->pf->fb_ops, &pf->sp_die,
1154                                               NULL) == 0) {
1155                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1156                         if (vf->args[vf->nargs].var == NULL) {
1157                                 vf->ret = -ENOMEM;
1158                                 return DIE_FIND_CB_END;
1159                         }
1160                         pr_debug(" %s", vf->args[vf->nargs].var);
1161                         vf->nargs++;
1162                 }
1163         }
1164
1165         if (dwarf_haspc(die_mem, vf->pf->addr))
1166                 return DIE_FIND_CB_CONTINUE;
1167         else
1168                 return DIE_FIND_CB_SIBLING;
1169 }
1170
1171 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1172                              struct perf_probe_arg *args)
1173 {
1174         Dwarf_Die die_mem;
1175         int i;
1176         int n = 0;
1177         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1178                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1179
1180         for (i = 0; i < pf->pev->nargs; i++) {
1181                 /* var never be NULL */
1182                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1183                         vf.vars = true;
1184                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1185                         /* Copy normal argument */
1186                         args[n] = pf->pev->args[i];
1187                         n++;
1188                         continue;
1189                 }
1190                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1191                 vf.nargs = n;
1192                 /* Special local variables */
1193                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1194                                &die_mem);
1195                 pr_debug(" (%d)\n", vf.nargs - n);
1196                 if (vf.ret < 0)
1197                         return vf.ret;
1198                 n = vf.nargs;
1199         }
1200         return n;
1201 }
1202
1203 /* Add a found probe point into trace event list */
1204 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1205 {
1206         struct trace_event_finder *tf =
1207                         container_of(pf, struct trace_event_finder, pf);
1208         struct perf_probe_point *pp = &pf->pev->point;
1209         struct probe_trace_event *tev;
1210         struct perf_probe_arg *args = NULL;
1211         int ret, i;
1212
1213         /* Check number of tevs */
1214         if (tf->ntevs == tf->max_tevs) {
1215                 pr_warning("Too many( > %d) probe point found.\n",
1216                            tf->max_tevs);
1217                 return -ERANGE;
1218         }
1219         tev = &tf->tevs[tf->ntevs++];
1220
1221         /* Trace point should be converted from subprogram DIE */
1222         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1223                                      pp->retprobe, pp->function, &tev->point);
1224         if (ret < 0)
1225                 goto end;
1226
1227         tev->point.realname = strdup(dwarf_diename(sc_die));
1228         if (!tev->point.realname) {
1229                 ret = -ENOMEM;
1230                 goto end;
1231         }
1232
1233         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1234                  tev->point.offset);
1235
1236         /* Expand special probe argument if exist */
1237         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1238         if (args == NULL) {
1239                 ret = -ENOMEM;
1240                 goto end;
1241         }
1242
1243         ret = expand_probe_args(sc_die, pf, args);
1244         if (ret < 0)
1245                 goto end;
1246
1247         tev->nargs = ret;
1248         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1249         if (tev->args == NULL) {
1250                 ret = -ENOMEM;
1251                 goto end;
1252         }
1253
1254         /* Find each argument */
1255         for (i = 0; i < tev->nargs; i++) {
1256                 pf->pvar = &args[i];
1257                 pf->tvar = &tev->args[i];
1258                 /* Variable should be found from scope DIE */
1259                 ret = find_variable(sc_die, pf);
1260                 if (ret != 0)
1261                         break;
1262         }
1263
1264 end:
1265         if (ret) {
1266                 clear_probe_trace_event(tev);
1267                 tf->ntevs--;
1268         }
1269         free(args);
1270         return ret;
1271 }
1272
1273 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1274 int debuginfo__find_trace_events(struct debuginfo *dbg,
1275                                  struct perf_probe_event *pev,
1276                                  struct probe_trace_event **tevs)
1277 {
1278         struct trace_event_finder tf = {
1279                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1280                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1281         int ret, i;
1282
1283         /* Allocate result tevs array */
1284         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1285         if (*tevs == NULL)
1286                 return -ENOMEM;
1287
1288         tf.tevs = *tevs;
1289         tf.ntevs = 0;
1290
1291         ret = debuginfo__find_probes(dbg, &tf.pf);
1292         if (ret < 0) {
1293                 for (i = 0; i < tf.ntevs; i++)
1294                         clear_probe_trace_event(&tf.tevs[i]);
1295                 zfree(tevs);
1296                 return ret;
1297         }
1298
1299         return (ret < 0) ? ret : tf.ntevs;
1300 }
1301
1302 /* Collect available variables in this scope */
1303 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1304 {
1305         struct available_var_finder *af = data;
1306         struct variable_list *vl;
1307         struct strbuf buf = STRBUF_INIT;
1308         int tag, ret;
1309
1310         vl = &af->vls[af->nvls - 1];
1311
1312         tag = dwarf_tag(die_mem);
1313         if (tag == DW_TAG_formal_parameter ||
1314             tag == DW_TAG_variable) {
1315                 ret = convert_variable_location(die_mem, af->pf.addr,
1316                                                 af->pf.fb_ops, &af->pf.sp_die,
1317                                                 NULL);
1318                 if (ret == 0 || ret == -ERANGE) {
1319                         int ret2;
1320                         bool externs = !af->child;
1321
1322                         if (strbuf_init(&buf, 64) < 0)
1323                                 goto error;
1324
1325                         if (probe_conf.show_location_range) {
1326                                 if (!externs)
1327                                         ret2 = strbuf_add(&buf,
1328                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1329                                 else
1330                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1331                                 if (ret2)
1332                                         goto error;
1333                         }
1334
1335                         ret2 = die_get_varname(die_mem, &buf);
1336
1337                         if (!ret2 && probe_conf.show_location_range &&
1338                                 !externs) {
1339                                 if (strbuf_addch(&buf, '\t') < 0)
1340                                         goto error;
1341                                 ret2 = die_get_var_range(&af->pf.sp_die,
1342                                                         die_mem, &buf);
1343                         }
1344
1345                         pr_debug("Add new var: %s\n", buf.buf);
1346                         if (ret2 == 0) {
1347                                 strlist__add(vl->vars,
1348                                         strbuf_detach(&buf, NULL));
1349                         }
1350                         strbuf_release(&buf);
1351                 }
1352         }
1353
1354         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1355                 return DIE_FIND_CB_CONTINUE;
1356         else
1357                 return DIE_FIND_CB_SIBLING;
1358 error:
1359         strbuf_release(&buf);
1360         pr_debug("Error in strbuf\n");
1361         return DIE_FIND_CB_END;
1362 }
1363
1364 /* Add a found vars into available variables list */
1365 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1366 {
1367         struct available_var_finder *af =
1368                         container_of(pf, struct available_var_finder, pf);
1369         struct perf_probe_point *pp = &pf->pev->point;
1370         struct variable_list *vl;
1371         Dwarf_Die die_mem;
1372         int ret;
1373
1374         /* Check number of tevs */
1375         if (af->nvls == af->max_vls) {
1376                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1377                 return -ERANGE;
1378         }
1379         vl = &af->vls[af->nvls++];
1380
1381         /* Trace point should be converted from subprogram DIE */
1382         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1383                                      pp->retprobe, pp->function, &vl->point);
1384         if (ret < 0)
1385                 return ret;
1386
1387         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1388                  vl->point.offset);
1389
1390         /* Find local variables */
1391         vl->vars = strlist__new(NULL, NULL);
1392         if (vl->vars == NULL)
1393                 return -ENOMEM;
1394         af->child = true;
1395         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1396
1397         /* Find external variables */
1398         if (!probe_conf.show_ext_vars)
1399                 goto out;
1400         /* Don't need to search child DIE for external vars. */
1401         af->child = false;
1402         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1403
1404 out:
1405         if (strlist__empty(vl->vars)) {
1406                 strlist__delete(vl->vars);
1407                 vl->vars = NULL;
1408         }
1409
1410         return ret;
1411 }
1412
1413 /*
1414  * Find available variables at given probe point
1415  * Return the number of found probe points. Return 0 if there is no
1416  * matched probe point. Return <0 if an error occurs.
1417  */
1418 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1419                                       struct perf_probe_event *pev,
1420                                       struct variable_list **vls)
1421 {
1422         struct available_var_finder af = {
1423                         .pf = {.pev = pev, .callback = add_available_vars},
1424                         .mod = dbg->mod,
1425                         .max_vls = probe_conf.max_probes};
1426         int ret;
1427
1428         /* Allocate result vls array */
1429         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1430         if (*vls == NULL)
1431                 return -ENOMEM;
1432
1433         af.vls = *vls;
1434         af.nvls = 0;
1435
1436         ret = debuginfo__find_probes(dbg, &af.pf);
1437         if (ret < 0) {
1438                 /* Free vlist for error */
1439                 while (af.nvls--) {
1440                         zfree(&af.vls[af.nvls].point.symbol);
1441                         strlist__delete(af.vls[af.nvls].vars);
1442                 }
1443                 zfree(vls);
1444                 return ret;
1445         }
1446
1447         return (ret < 0) ? ret : af.nvls;
1448 }
1449
1450 /* For the kernel module, we need a special code to get a DIE */
1451 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1452 {
1453         int n, i;
1454         Elf32_Word shndx;
1455         Elf_Scn *scn;
1456         Elf *elf;
1457         GElf_Shdr mem, *shdr;
1458         const char *p;
1459
1460         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1461         if (!elf)
1462                 return -EINVAL;
1463
1464         /* Get the number of relocations */
1465         n = dwfl_module_relocations(dbg->mod);
1466         if (n < 0)
1467                 return -ENOENT;
1468         /* Search the relocation related .text section */
1469         for (i = 0; i < n; i++) {
1470                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1471                 if (strcmp(p, ".text") == 0) {
1472                         /* OK, get the section header */
1473                         scn = elf_getscn(elf, shndx);
1474                         if (!scn)
1475                                 return -ENOENT;
1476                         shdr = gelf_getshdr(scn, &mem);
1477                         if (!shdr)
1478                                 return -ENOENT;
1479                         *offs = shdr->sh_addr;
1480                 }
1481         }
1482         return 0;
1483 }
1484
1485 /* Reverse search */
1486 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1487                                 struct perf_probe_point *ppt)
1488 {
1489         Dwarf_Die cudie, spdie, indie;
1490         Dwarf_Addr _addr = 0, baseaddr = 0;
1491         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1492         int baseline = 0, lineno = 0, ret = 0;
1493         bool reloc = false;
1494
1495 retry:
1496         /* Find cu die */
1497         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1498                 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1499                         addr += baseaddr;
1500                         reloc = true;
1501                         goto retry;
1502                 }
1503                 pr_warning("Failed to find debug information for address %lx\n",
1504                            addr);
1505                 ret = -EINVAL;
1506                 goto end;
1507         }
1508
1509         /* Find a corresponding line (filename and lineno) */
1510         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1511         /* Don't care whether it failed or not */
1512
1513         /* Find a corresponding function (name, baseline and baseaddr) */
1514         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1515                 /* Get function entry information */
1516                 func = basefunc = dwarf_diename(&spdie);
1517                 if (!func ||
1518                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1519                     dwarf_decl_line(&spdie, &baseline) != 0) {
1520                         lineno = 0;
1521                         goto post;
1522                 }
1523
1524                 fname = dwarf_decl_file(&spdie);
1525                 if (addr == (unsigned long)baseaddr) {
1526                         /* Function entry - Relative line number is 0 */
1527                         lineno = baseline;
1528                         goto post;
1529                 }
1530
1531                 /* Track down the inline functions step by step */
1532                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1533                                                 &indie)) {
1534                         /* There is an inline function */
1535                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1536                             _addr == addr) {
1537                                 /*
1538                                  * addr is at an inline function entry.
1539                                  * In this case, lineno should be the call-site
1540                                  * line number. (overwrite lineinfo)
1541                                  */
1542                                 lineno = die_get_call_lineno(&indie);
1543                                 fname = die_get_call_file(&indie);
1544                                 break;
1545                         } else {
1546                                 /*
1547                                  * addr is in an inline function body.
1548                                  * Since lineno points one of the lines
1549                                  * of the inline function, baseline should
1550                                  * be the entry line of the inline function.
1551                                  */
1552                                 tmp = dwarf_diename(&indie);
1553                                 if (!tmp ||
1554                                     dwarf_decl_line(&indie, &baseline) != 0)
1555                                         break;
1556                                 func = tmp;
1557                                 spdie = indie;
1558                         }
1559                 }
1560                 /* Verify the lineno and baseline are in a same file */
1561                 tmp = dwarf_decl_file(&spdie);
1562                 if (!tmp || strcmp(tmp, fname) != 0)
1563                         lineno = 0;
1564         }
1565
1566 post:
1567         /* Make a relative line number or an offset */
1568         if (lineno)
1569                 ppt->line = lineno - baseline;
1570         else if (basefunc) {
1571                 ppt->offset = addr - (unsigned long)baseaddr;
1572                 func = basefunc;
1573         }
1574
1575         /* Duplicate strings */
1576         if (func) {
1577                 ppt->function = strdup(func);
1578                 if (ppt->function == NULL) {
1579                         ret = -ENOMEM;
1580                         goto end;
1581                 }
1582         }
1583         if (fname) {
1584                 ppt->file = strdup(fname);
1585                 if (ppt->file == NULL) {
1586                         zfree(&ppt->function);
1587                         ret = -ENOMEM;
1588                         goto end;
1589                 }
1590         }
1591 end:
1592         if (ret == 0 && (fname || func))
1593                 ret = 1;        /* Found a point */
1594         return ret;
1595 }
1596
1597 /* Add a line and store the src path */
1598 static int line_range_add_line(const char *src, unsigned int lineno,
1599                                struct line_range *lr)
1600 {
1601         /* Copy source path */
1602         if (!lr->path) {
1603                 lr->path = strdup(src);
1604                 if (lr->path == NULL)
1605                         return -ENOMEM;
1606         }
1607         return intlist__add(lr->line_list, lineno);
1608 }
1609
1610 static int line_range_walk_cb(const char *fname, int lineno,
1611                               Dwarf_Addr addr __maybe_unused,
1612                               void *data)
1613 {
1614         struct line_finder *lf = data;
1615         int err;
1616
1617         if ((strtailcmp(fname, lf->fname) != 0) ||
1618             (lf->lno_s > lineno || lf->lno_e < lineno))
1619                 return 0;
1620
1621         err = line_range_add_line(fname, lineno, lf->lr);
1622         if (err < 0 && err != -EEXIST)
1623                 return err;
1624
1625         return 0;
1626 }
1627
1628 /* Find line range from its line number */
1629 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1630 {
1631         int ret;
1632
1633         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1634
1635         /* Update status */
1636         if (ret >= 0)
1637                 if (!intlist__empty(lf->lr->line_list))
1638                         ret = lf->found = 1;
1639                 else
1640                         ret = 0;        /* Lines are not found */
1641         else {
1642                 zfree(&lf->lr->path);
1643         }
1644         return ret;
1645 }
1646
1647 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1648 {
1649         int ret = find_line_range_by_line(in_die, data);
1650
1651         /*
1652          * We have to check all instances of inlined function, because
1653          * some execution paths can be optimized out depends on the
1654          * function argument of instances. However, if an error occurs,
1655          * it should be handled by the caller.
1656          */
1657         return ret < 0 ? ret : 0;
1658 }
1659
1660 /* Search function definition from function name */
1661 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1662 {
1663         struct dwarf_callback_param *param = data;
1664         struct line_finder *lf = param->data;
1665         struct line_range *lr = lf->lr;
1666
1667         /* Check declared file */
1668         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1669                 return DWARF_CB_OK;
1670
1671         if (die_is_func_def(sp_die) &&
1672             die_match_name(sp_die, lr->function)) {
1673                 lf->fname = dwarf_decl_file(sp_die);
1674                 dwarf_decl_line(sp_die, &lr->offset);
1675                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1676                 lf->lno_s = lr->offset + lr->start;
1677                 if (lf->lno_s < 0)      /* Overflow */
1678                         lf->lno_s = INT_MAX;
1679                 lf->lno_e = lr->offset + lr->end;
1680                 if (lf->lno_e < 0)      /* Overflow */
1681                         lf->lno_e = INT_MAX;
1682                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1683                 lr->start = lf->lno_s;
1684                 lr->end = lf->lno_e;
1685                 if (!die_is_func_instance(sp_die))
1686                         param->retval = die_walk_instances(sp_die,
1687                                                 line_range_inline_cb, lf);
1688                 else
1689                         param->retval = find_line_range_by_line(sp_die, lf);
1690                 return DWARF_CB_ABORT;
1691         }
1692         return DWARF_CB_OK;
1693 }
1694
1695 static int find_line_range_by_func(struct line_finder *lf)
1696 {
1697         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1698         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1699         return param.retval;
1700 }
1701
1702 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1703 {
1704         struct line_finder lf = {.lr = lr, .found = 0};
1705         int ret = 0;
1706         Dwarf_Off off = 0, noff;
1707         size_t cuhl;
1708         Dwarf_Die *diep;
1709         const char *comp_dir;
1710
1711         /* Fastpath: lookup by function name from .debug_pubnames section */
1712         if (lr->function) {
1713                 struct pubname_callback_param pubname_param = {
1714                         .function = lr->function, .file = lr->file,
1715                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1716                 struct dwarf_callback_param line_range_param = {
1717                         .data = (void *)&lf, .retval = 0};
1718
1719                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1720                                   &pubname_param, 0);
1721                 if (pubname_param.found) {
1722                         line_range_search_cb(&lf.sp_die, &line_range_param);
1723                         if (lf.found)
1724                                 goto found;
1725                 }
1726         }
1727
1728         /* Loop on CUs (Compilation Unit) */
1729         while (!lf.found && ret >= 0) {
1730                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1731                                  NULL, NULL, NULL) != 0)
1732                         break;
1733
1734                 /* Get the DIE(Debugging Information Entry) of this CU */
1735                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1736                 if (!diep)
1737                         continue;
1738
1739                 /* Check if target file is included. */
1740                 if (lr->file)
1741                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1742                 else
1743                         lf.fname = 0;
1744
1745                 if (!lr->file || lf.fname) {
1746                         if (lr->function)
1747                                 ret = find_line_range_by_func(&lf);
1748                         else {
1749                                 lf.lno_s = lr->start;
1750                                 lf.lno_e = lr->end;
1751                                 ret = find_line_range_by_line(NULL, &lf);
1752                         }
1753                 }
1754                 off = noff;
1755         }
1756
1757 found:
1758         /* Store comp_dir */
1759         if (lf.found) {
1760                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1761                 if (comp_dir) {
1762                         lr->comp_dir = strdup(comp_dir);
1763                         if (!lr->comp_dir)
1764                                 ret = -ENOMEM;
1765                 }
1766         }
1767
1768         pr_debug("path: %s\n", lr->path);
1769         return (ret < 0) ? ret : lf.found;
1770 }
1771
1772 /*
1773  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1774  * and chop off leading directories that do not exist. Result is passed back as
1775  * a newly allocated path on success.
1776  * Return 0 if file was found and readable, -errno otherwise.
1777  */
1778 int get_real_path(const char *raw_path, const char *comp_dir,
1779                          char **new_path)
1780 {
1781         const char *prefix = symbol_conf.source_prefix;
1782
1783         if (!prefix) {
1784                 if (raw_path[0] != '/' && comp_dir)
1785                         /* If not an absolute path, try to use comp_dir */
1786                         prefix = comp_dir;
1787                 else {
1788                         if (access(raw_path, R_OK) == 0) {
1789                                 *new_path = strdup(raw_path);
1790                                 return *new_path ? 0 : -ENOMEM;
1791                         } else
1792                                 return -errno;
1793                 }
1794         }
1795
1796         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1797         if (!*new_path)
1798                 return -ENOMEM;
1799
1800         for (;;) {
1801                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1802
1803                 if (access(*new_path, R_OK) == 0)
1804                         return 0;
1805
1806                 if (!symbol_conf.source_prefix) {
1807                         /* In case of searching comp_dir, don't retry */
1808                         zfree(new_path);
1809                         return -errno;
1810                 }
1811
1812                 switch (errno) {
1813                 case ENAMETOOLONG:
1814                 case ENOENT:
1815                 case EROFS:
1816                 case EFAULT:
1817                         raw_path = strchr(++raw_path, '/');
1818                         if (!raw_path) {
1819                                 zfree(new_path);
1820                                 return -ENOENT;
1821                         }
1822                         continue;
1823
1824                 default:
1825                         zfree(new_path);
1826                         return -errno;
1827                 }
1828         }
1829 }