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                                      unsigned int machine,
 175                                      struct probe_trace_arg *tvar)
 176 {
 177         Dwarf_Attribute attr;
 178         Dwarf_Addr tmp = 0;
 179         Dwarf_Op *op;
 180         size_t nops;
 181         unsigned int regn;
 182         Dwarf_Word offs = 0;
 183         bool ref = false;
 184         const char *regs;
 185         int ret, ret2 = 0;
 186
 187         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 188                 goto static_var;
 189
 190         /* TODO: handle more than 1 exprs */
 191         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 192                 return -EINVAL; /* Broken DIE ? */
 193         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 194                 ret = dwarf_entrypc(sp_die, &tmp);
 195                 if (ret)
 196                         return -ENOENT;
 197
 198                 if (probe_conf.show_location_range &&
 199                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 200                         ret2 = -ERANGE;
 201                 } else if (addr != tmp ||
 202                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 203                         return -ENOENT;
 204                 }
 205
 206                 ret = dwarf_highpc(sp_die, &tmp);
 207                 if (ret)
 208                         return -ENOENT;
 209                 /*
 210                  * This is fuzzed by fentry mcount. We try to find the
 211                  * parameter location at the earliest address.
 212                  */
 213                 for (addr += 1; addr <= tmp; addr++) {
 214                         if (dwarf_getlocation_addr(&attr, addr, &op,
 215                                                    &nops, 1) > 0)
 216                                 goto found;
 217                 }
 218                 return -ENOENT;
 219         }
 220 found:
 221         if (nops == 0)
 222                 /* TODO: Support const_value */
 223                 return -ENOENT;
 224
 225         if (op->atom == DW_OP_addr) {
 226 static_var:
 227                 if (!tvar)
 228                         return ret2;
 229                 /* Static variables on memory (not stack), make @varname */
 230                 ret = strlen(dwarf_diename(vr_die));
 231                 tvar->value = zalloc(ret + 2);
 232                 if (tvar->value == NULL)
 233                         return -ENOMEM;
 234                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 235                 tvar->ref = alloc_trace_arg_ref((long)offs);
 236                 if (tvar->ref == NULL)
 237                         return -ENOMEM;
 238                 return ret2;
 239         }
 240
 241         /* If this is based on frame buffer, set the offset */
 242         if (op->atom == DW_OP_fbreg) {
 243                 if (fb_ops == NULL)
 244                         return -ENOTSUP;
 245                 ref = true;
 246                 offs = op->number;
 247                 op = &fb_ops[0];
 248         }
 249
 250         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 251                 regn = op->atom - DW_OP_breg0;
 252                 offs += op->number;
 253                 ref = true;
 254         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 255                 regn = op->atom - DW_OP_reg0;
 256         } else if (op->atom == DW_OP_bregx) {
 257                 regn = op->number;
 258                 offs += op->number2;
 259                 ref = true;
 260         } else if (op->atom == DW_OP_regx) {
 261                 regn = op->number;
 262         } else {
 263                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 264                 return -ENOTSUP;
 265         }
 266
 267         if (!tvar)
 268                 return ret2;
 269
 270         regs = get_dwarf_regstr(regn, machine);
 271         if (!regs) {
 272                 /* This should be a bug in DWARF or this tool */
 273                 pr_warning("Mapping for the register number %u "
 274                            "missing on this architecture.\n", regn);
 275                 return -ENOTSUP;
 276         }
 277
 278         tvar->value = strdup(regs);
 279         if (tvar->value == NULL)
 280                 return -ENOMEM;
 281
 282         if (ref) {
 283                 tvar->ref = alloc_trace_arg_ref((long)offs);
 284                 if (tvar->ref == NULL)
 285                         return -ENOMEM;
 286         }
 287         return ret2;
 288 }
 289
 290 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 291
 292 static int convert_variable_type(Dwarf_Die *vr_die,
 293                                  struct probe_trace_arg *tvar,
 294                                  const char *cast)
 295 {
 296         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 297         Dwarf_Die type;
 298         char buf[16];
 299         char sbuf[STRERR_BUFSIZE];
 300         int bsize, boffs, total;
 301         int ret;
 302         char prefix;
 303
 304         /* TODO: check all types */
 305         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 306             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 307                 /* Non string type is OK */
 308                 /* and respect signedness/hexadecimal cast */
 309                 tvar->type = strdup(cast);
 310                 return (tvar->type == NULL) ? -ENOMEM : 0;
 311         }
 312
 313         bsize = dwarf_bitsize(vr_die);
 314         if (bsize > 0) {
 315                 /* This is a bitfield */
 316                 boffs = dwarf_bitoffset(vr_die);
 317                 total = dwarf_bytesize(vr_die);
 318                 if (boffs < 0 || total < 0)
 319                         return -ENOENT;
 320                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 321                                 BYTES_TO_BITS(total));
 322                 goto formatted;
 323         }
 324
 325         if (die_get_real_type(vr_die, &type) == NULL) {
 326                 pr_warning("Failed to get a type information of %s.\n",
 327                            dwarf_diename(vr_die));
 328                 return -ENOENT;
 329         }
 330
 331         pr_debug("%s type is %s.\n",
 332                  dwarf_diename(vr_die), dwarf_diename(&type));
 333
 334         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 335                 ret = dwarf_tag(&type);
 336                 if (ret != DW_TAG_pointer_type &&
 337                     ret != DW_TAG_array_type) {
 338                         pr_warning("Failed to cast into string: "
 339                                    "%s(%s) is not a pointer nor array.\n",
 340                                    dwarf_diename(vr_die), dwarf_diename(&type));
 341                         return -EINVAL;
 342                 }
 343                 if (die_get_real_type(&type, &type) == NULL) {
 344                         pr_warning("Failed to get a type"
 345                                    " information.\n");
 346                         return -ENOENT;
 347                 }
 348                 if (ret == DW_TAG_pointer_type) {
 349                         while (*ref_ptr)
 350                                 ref_ptr = &(*ref_ptr)->next;
 351                         /* Add new reference with offset +0 */
 352                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 353                         if (*ref_ptr == NULL) {
 354                                 pr_warning("Out of memory error\n");
 355                                 return -ENOMEM;
 356                         }
 357                 }
 358                 if (!die_compare_name(&type, "char") &&
 359                     !die_compare_name(&type, "unsigned char")) {
 360                         pr_warning("Failed to cast into string: "
 361                                    "%s is not (unsigned) char *.\n",
 362                                    dwarf_diename(vr_die));
 363                         return -EINVAL;
 364                 }
 365                 tvar->type = strdup(cast);
 366                 return (tvar->type == NULL) ? -ENOMEM : 0;
 367         }
 368
 369         if (cast && (strcmp(cast, "u") == 0))
 370                 prefix = 'u';
 371         else if (cast && (strcmp(cast, "s") == 0))
 372                 prefix = 's';
 373         else if (cast && (strcmp(cast, "x") == 0) &&
 374                  probe_type_is_available(PROBE_TYPE_X))
 375                 prefix = 'x';
 376         else
 377                 prefix = die_is_signed_type(&type) ? 's' :
 378                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 379
 380         ret = dwarf_bytesize(&type);
 381         if (ret <= 0)
 382                 /* No size ... try to use default type */
 383                 return 0;
 384         ret = BYTES_TO_BITS(ret);
 385
 386         /* Check the bitwidth */
 387         if (ret > MAX_BASIC_TYPE_BITS) {
 388                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 389                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 390                 ret = MAX_BASIC_TYPE_BITS;
 391         }
 392         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 393
 394 formatted:
 395         if (ret < 0 || ret >= 16) {
 396                 if (ret >= 16)
 397                         ret = -E2BIG;
 398                 pr_warning("Failed to convert variable type: %s\n",
 399                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 400                 return ret;
 401         }
 402         tvar->type = strdup(buf);
 403         if (tvar->type == NULL)
 404                 return -ENOMEM;
 405         return 0;
 406 }
 407
 408 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 409                                     struct perf_probe_arg_field *field,
 410                                     struct probe_trace_arg_ref **ref_ptr,
 411                                     Dwarf_Die *die_mem)
 412 {
 413         struct probe_trace_arg_ref *ref = *ref_ptr;
 414         Dwarf_Die type;
 415         Dwarf_Word offs;
 416         int ret, tag;
 417
 418         pr_debug("converting %s in %s\n", field->name, varname);
 419         if (die_get_real_type(vr_die, &type) == NULL) {
 420                 pr_warning("Failed to get the type of %s.\n", varname);
 421                 return -ENOENT;
 422         }
 423         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 424         tag = dwarf_tag(&type);
 425
 426         if (field->name[0] == '[' &&
 427             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 428                 if (field->next)
 429                         /* Save original type for next field */
 430                         memcpy(die_mem, &type, sizeof(*die_mem));
 431                 /* Get the type of this array */
 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                 pr_debug2("Array real type: (%x)\n",
 437                          (unsigned)dwarf_dieoffset(&type));
 438                 if (tag == DW_TAG_pointer_type) {
 439                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 440                         if (ref == NULL)
 441                                 return -ENOMEM;
 442                         if (*ref_ptr)
 443                                 (*ref_ptr)->next = ref;
 444                         else
 445                                 *ref_ptr = ref;
 446                 }
 447                 ref->offset += dwarf_bytesize(&type) * field->index;
 448                 if (!field->next)
 449                         /* Save vr_die for converting types */
 450                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 451                 goto next;
 452         } else if (tag == DW_TAG_pointer_type) {
 453                 /* Check the pointer and dereference */
 454                 if (!field->ref) {
 455                         pr_err("Semantic error: %s must be referred by '->'\n",
 456                                field->name);
 457                         return -EINVAL;
 458                 }
 459                 /* Get the type pointed by this pointer */
 460                 if (die_get_real_type(&type, &type) == NULL) {
 461                         pr_warning("Failed to get the type of %s.\n", varname);
 462                         return -ENOENT;
 463                 }
 464                 /* Verify it is a data structure  */
 465                 tag = dwarf_tag(&type);
 466                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 467                         pr_warning("%s is not a data structure nor an union.\n",
 468                                    varname);
 469                         return -EINVAL;
 470                 }
 471
 472                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 473                 if (ref == NULL)
 474                         return -ENOMEM;
 475                 if (*ref_ptr)
 476                         (*ref_ptr)->next = ref;
 477                 else
 478                         *ref_ptr = ref;
 479         } else {
 480                 /* Verify it is a data structure  */
 481                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 482                         pr_warning("%s is not a data structure nor an union.\n",
 483                                    varname);
 484                         return -EINVAL;
 485                 }
 486                 if (field->name[0] == '[') {
 487                         pr_err("Semantic error: %s is not a pointer"
 488                                " nor array.\n", varname);
 489                         return -EINVAL;
 490                 }
 491                 /* While prcessing unnamed field, we don't care about this */
 492                 if (field->ref && dwarf_diename(vr_die)) {
 493                         pr_err("Semantic error: %s must be referred by '.'\n",
 494                                field->name);
 495                         return -EINVAL;
 496                 }
 497                 if (!ref) {
 498                         pr_warning("Structure on a register is not "
 499                                    "supported yet.\n");
 500                         return -ENOTSUP;
 501                 }
 502         }
 503
 504         if (die_find_member(&type, field->name, die_mem) == NULL) {
 505                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 506                            dwarf_diename(&type), field->name);
 507                 return -EINVAL;
 508         }
 509
 510         /* Get the offset of the field */
 511         if (tag == DW_TAG_union_type) {
 512                 offs = 0;
 513         } else {
 514                 ret = die_get_data_member_location(die_mem, &offs);
 515                 if (ret < 0) {
 516                         pr_warning("Failed to get the offset of %s.\n",
 517                                    field->name);
 518                         return ret;
 519                 }
 520         }
 521         ref->offset += (long)offs;
 522
 523         /* If this member is unnamed, we need to reuse this field */
 524         if (!dwarf_diename(die_mem))
 525                 return convert_variable_fields(die_mem, varname, field,
 526                                                 &ref, die_mem);
 527
 528 next:
 529         /* Converting next field */
 530         if (field->next)
 531                 return convert_variable_fields(die_mem, field->name,
 532                                         field->next, &ref, die_mem);
 533         else
 534                 return 0;
 535 }
 536
 537 /* Show a variables in kprobe event format */
 538 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 539 {
 540         Dwarf_Die die_mem;
 541         int ret;
 542
 543         pr_debug("Converting variable %s into trace event.\n",
 544                  dwarf_diename(vr_die));
 545
 546         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 547                                         &pf->sp_die, pf->machine, pf->tvar);
 548         if (ret == -ENOENT || ret == -EINVAL) {
 549                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 550                        " Perhaps it has been optimized out.\n"
 551                        " Use -V with the --range option to show '%s' location range.\n",
 552                        pf->pvar->var, pf->pvar->var);
 553         } else if (ret == -ENOTSUP)
 554                 pr_err("Sorry, we don't support this variable location yet.\n");
 555         else if (ret == 0 && pf->pvar->field) {
 556                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 557                                               pf->pvar->field, &pf->tvar->ref,
 558                                               &die_mem);
 559                 vr_die = &die_mem;
 560         }
 561         if (ret == 0)
 562                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 563         /* *expr will be cached in libdw. Don't free it. */
 564         return ret;
 565 }
 566
 567 /* Find a variable in a scope DIE */
 568 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 569 {
 570         Dwarf_Die vr_die;
 571         char *buf, *ptr;
 572         int ret = 0;
 573
 574         /* Copy raw parameters */
 575         if (!is_c_varname(pf->pvar->var))
 576                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 577
 578         if (pf->pvar->name)
 579                 pf->tvar->name = strdup(pf->pvar->name);
 580         else {
 581                 buf = synthesize_perf_probe_arg(pf->pvar);
 582                 if (!buf)
 583                         return -ENOMEM;
 584                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 585                 if (ptr)
 586                         *ptr = '_';
 587                 pf->tvar->name = buf;
 588         }
 589         if (pf->tvar->name == NULL)
 590                 return -ENOMEM;
 591
 592         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 593         /* Search child die for local variables and parameters. */
 594         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 595                 /* Search again in global variables */
 596                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 597                                                 0, &vr_die)) {
 598                         pr_warning("Failed to find '%s' in this function.\n",
 599                                    pf->pvar->var);
 600                         ret = -ENOENT;
 601                 }
 602         }
 603         if (ret >= 0)
 604                 ret = convert_variable(&vr_die, pf);
 605
 606         return ret;
 607 }
 608
 609 /* Convert subprogram DIE to trace point */
 610 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 611                                   Dwarf_Addr paddr, bool retprobe,
 612                                   const char *function,
 613                                   struct probe_trace_point *tp)
 614 {
 615         Dwarf_Addr eaddr, highaddr;
 616         GElf_Sym sym;
 617         const char *symbol;
 618
 619         /* Verify the address is correct */
 620         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 621                 pr_warning("Failed to get entry address of %s\n",
 622                            dwarf_diename(sp_die));
 623                 return -ENOENT;
 624         }
 625         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 626                 pr_warning("Failed to get end address of %s\n",
 627                            dwarf_diename(sp_die));
 628                 return -ENOENT;
 629         }
 630         if (paddr > highaddr) {
 631                 pr_warning("Offset specified is greater than size of %s\n",
 632                            dwarf_diename(sp_die));
 633                 return -EINVAL;
 634         }
 635
 636         symbol = dwarf_diename(sp_die);
 637         if (!symbol) {
 638                 /* Try to get the symbol name from symtab */
 639                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 640                 if (!symbol) {
 641                         pr_warning("Failed to find symbol at 0x%lx\n",
 642                                    (unsigned long)paddr);
 643                         return -ENOENT;
 644                 }
 645                 eaddr = sym.st_value;
 646         }
 647         tp->offset = (unsigned long)(paddr - eaddr);
 648         tp->address = (unsigned long)paddr;
 649         tp->symbol = strdup(symbol);
 650         if (!tp->symbol)
 651                 return -ENOMEM;
 652
 653         /* Return probe must be on the head of a subprogram */
 654         if (retprobe) {
 655                 if (eaddr != paddr) {
 656                         pr_warning("Failed to find \"%s%%return\",\n"
 657                                    " because %s is an inlined function and"
 658                                    " has no return point.\n", function,
 659                                    function);
 660                         return -EINVAL;
 661                 }
 662                 tp->retprobe = true;
 663         }
 664
 665         return 0;
 666 }
 667
 668 /* Call probe_finder callback with scope DIE */
 669 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 670 {
 671         Dwarf_Attribute fb_attr;
 672         Dwarf_Frame *frame = NULL;
 673         size_t nops;
 674         int ret;
 675
 676         if (!sc_die) {
 677                 pr_err("Caller must pass a scope DIE. Program error.\n");
 678                 return -EINVAL;
 679         }
 680
 681         /* If not a real subprogram, find a real one */
 682         if (!die_is_func_def(sc_die)) {
 683                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 684                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 685                                 pr_warning("Ignoring tail call from %s\n",
 686                                                 dwarf_diename(&pf->sp_die));
 687                                 return 0;
 688                         } else {
 689                                 pr_warning("Failed to find probe point in any "
 690                                            "functions.\n");
 691                                 return -ENOENT;
 692                         }
 693                 }
 694         } else
 695                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 696
 697         /* Get the frame base attribute/ops from subprogram */
 698         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 699         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 700         if (ret <= 0 || nops == 0) {
 701                 pf->fb_ops = NULL;
 702 #if _ELFUTILS_PREREQ(0, 142)
 703         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 704                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 705                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 706                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 707                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 708                         pr_warning("Failed to get call frame on 0x%jx\n",
 709                                    (uintmax_t)pf->addr);
 710                         free(frame);
 711                         return -ENOENT;
 712                 }
 713 #endif
 714         }
 715
 716         /* Call finder's callback handler */
 717         ret = pf->callback(sc_die, pf);
 718
 719         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 720         free(frame);
 721         pf->fb_ops = NULL;
 722
 723         return ret;
 724 }
 725
 726 struct find_scope_param {
 727         const char *function;
 728         const char *file;
 729         int line;
 730         int diff;
 731         Dwarf_Die *die_mem;
 732         bool found;
 733 };
 734
 735 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 736 {
 737         struct find_scope_param *fsp = data;
 738         const char *file;
 739         int lno;
 740
 741         /* Skip if declared file name does not match */
 742         if (fsp->file) {
 743                 file = dwarf_decl_file(fn_die);
 744                 if (!file || strcmp(fsp->file, file) != 0)
 745                         return 0;
 746         }
 747         /* If the function name is given, that's what user expects */
 748         if (fsp->function) {
 749                 if (die_match_name(fn_die, fsp->function)) {
 750                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 751                         fsp->found = true;
 752                         return 1;
 753                 }
 754         } else {
 755                 /* With the line number, find the nearest declared DIE */
 756                 dwarf_decl_line(fn_die, &lno);
 757                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 758                         /* Keep a candidate and continue */
 759                         fsp->diff = fsp->line - lno;
 760                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 761                         fsp->found = true;
 762                 }
 763         }
 764         return 0;
 765 }
 766
 767 /* Find an appropriate scope fits to given conditions */
 768 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 769 {
 770         struct find_scope_param fsp = {
 771                 .function = pf->pev->point.function,
 772                 .file = pf->fname,
 773                 .line = pf->lno,
 774                 .diff = INT_MAX,
 775                 .die_mem = die_mem,
 776                 .found = false,
 777         };
 778
 779         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 780
 781         return fsp.found ? die_mem : NULL;
 782 }
 783
 784 static int probe_point_line_walker(const char *fname, int lineno,
 785                                    Dwarf_Addr addr, void *data)
 786 {
 787         struct probe_finder *pf = data;
 788         Dwarf_Die *sc_die, die_mem;
 789         int ret;
 790
 791         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 792                 return 0;
 793
 794         pf->addr = addr;
 795         sc_die = find_best_scope(pf, &die_mem);
 796         if (!sc_die) {
 797                 pr_warning("Failed to find scope of probe point.\n");
 798                 return -ENOENT;
 799         }
 800
 801         ret = call_probe_finder(sc_die, pf);
 802
 803         /* Continue if no error, because the line will be in inline function */
 804         return ret < 0 ? ret : 0;
 805 }
 806
 807 /* Find probe point from its line number */
 808 static int find_probe_point_by_line(struct probe_finder *pf)
 809 {
 810         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 811 }
 812
 813 /* Find lines which match lazy pattern */
 814 static int find_lazy_match_lines(struct intlist *list,
 815                                  const char *fname, const char *pat)
 816 {
 817         FILE *fp;
 818         char *line = NULL;
 819         size_t line_len;
 820         ssize_t len;
 821         int count = 0, linenum = 1;
 822         char sbuf[STRERR_BUFSIZE];
 823
 824         fp = fopen(fname, "r");
 825         if (!fp) {
 826                 pr_warning("Failed to open %s: %s\n", fname,
 827                            str_error_r(errno, sbuf, sizeof(sbuf)));
 828                 return -errno;
 829         }
 830
 831         while ((len = getline(&line, &line_len, fp)) > 0) {
 832
 833                 if (line[len - 1] == '\n')
 834                         line[len - 1] = '\0';
 835
 836                 if (strlazymatch(line, pat)) {
 837                         intlist__add(list, linenum);
 838                         count++;
 839                 }
 840                 linenum++;
 841         }
 842
 843         if (ferror(fp))
 844                 count = -errno;
 845         free(line);
 846         fclose(fp);
 847
 848         if (count == 0)
 849                 pr_debug("No matched lines found in %s.\n", fname);
 850         return count;
 851 }
 852
 853 static int probe_point_lazy_walker(const char *fname, int lineno,
 854                                    Dwarf_Addr addr, void *data)
 855 {
 856         struct probe_finder *pf = data;
 857         Dwarf_Die *sc_die, die_mem;
 858         int ret;
 859
 860         if (!intlist__has_entry(pf->lcache, lineno) ||
 861             strtailcmp(fname, pf->fname) != 0)
 862                 return 0;
 863
 864         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 865                  lineno, (unsigned long long)addr);
 866         pf->addr = addr;
 867         pf->lno = lineno;
 868         sc_die = find_best_scope(pf, &die_mem);
 869         if (!sc_die) {
 870                 pr_warning("Failed to find scope of probe point.\n");
 871                 return -ENOENT;
 872         }
 873
 874         ret = call_probe_finder(sc_die, pf);
 875
 876         /*
 877          * Continue if no error, because the lazy pattern will match
 878          * to other lines
 879          */
 880         return ret < 0 ? ret : 0;
 881 }
 882
 883 /* Find probe points from lazy pattern  */
 884 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 885 {
 886         int ret = 0;
 887         char *fpath;
 888
 889         if (intlist__empty(pf->lcache)) {
 890                 const char *comp_dir;
 891
 892                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 893                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 894                 if (ret < 0) {
 895                         pr_warning("Failed to find source file path.\n");
 896                         return ret;
 897                 }
 898
 899                 /* Matching lazy line pattern */
 900                 ret = find_lazy_match_lines(pf->lcache, fpath,
 901                                             pf->pev->point.lazy_line);
 902                 free(fpath);
 903                 if (ret <= 0)
 904                         return ret;
 905         }
 906
 907         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 908 }
 909
 910 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 911 {
 912         struct perf_probe_point *pp = &pf->pev->point;
 913
 914         /* Not uprobe? */
 915         if (!pf->pev->uprobes)
 916                 return;
 917
 918         /* Compiled with optimization? */
 919         if (die_is_optimized_target(&pf->cu_die))
 920                 return;
 921
 922         /* Don't know entrypc? */
 923         if (!pf->addr)
 924                 return;
 925
 926         /* Only FUNC and FUNC@SRC are eligible. */
 927         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 928             pp->offset || pp->abs_address)
 929                 return;
 930
 931         /* Not interested in func parameter? */
 932         if (!perf_probe_with_var(pf->pev))
 933                 return;
 934
 935         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 936                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 937                 pf->addr);
 938
 939         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 940 }
 941
 942 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 943 {
 944         struct probe_finder *pf = data;
 945         struct perf_probe_point *pp = &pf->pev->point;
 946         Dwarf_Addr addr;
 947         int ret;
 948
 949         if (pp->lazy_line)
 950                 ret = find_probe_point_lazy(in_die, pf);
 951         else {
 952                 /* Get probe address */
 953                 if (dwarf_entrypc(in_die, &addr) != 0) {
 954                         pr_warning("Failed to get entry address of %s.\n",
 955                                    dwarf_diename(in_die));
 956                         return -ENOENT;
 957                 }
 958                 if (addr == 0) {
 959                         pr_debug("%s has no valid entry address. skipped.\n",
 960                                  dwarf_diename(in_die));
 961                         return -ENOENT;
 962                 }
 963                 pf->addr = addr;
 964                 pf->addr += pp->offset;
 965                 pr_debug("found inline addr: 0x%jx\n",
 966                          (uintmax_t)pf->addr);
 967
 968                 ret = call_probe_finder(in_die, pf);
 969         }
 970
 971         return ret;
 972 }
 973
 974 /* Callback parameter with return value for libdw */
 975 struct dwarf_callback_param {
 976         void *data;
 977         int retval;
 978 };
 979
 980 /* Search function from function name */
 981 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 982 {
 983         struct dwarf_callback_param *param = data;
 984         struct probe_finder *pf = param->data;
 985         struct perf_probe_point *pp = &pf->pev->point;
 986
 987         /* Check tag and diename */
 988         if (!die_is_func_def(sp_die) ||
 989             !die_match_name(sp_die, pp->function))
 990                 return DWARF_CB_OK;
 991
 992         /* Check declared file */
 993         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 994                 return DWARF_CB_OK;
 995
 996         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
 997                  (unsigned long)dwarf_dieoffset(sp_die));
 998         pf->fname = dwarf_decl_file(sp_die);
 999         if (pp->line) { /* Function relative line */
1000                 dwarf_decl_line(sp_die, &pf->lno);
1001                 pf->lno += pp->line;
1002                 param->retval = find_probe_point_by_line(pf);
1003         } else if (die_is_func_instance(sp_die)) {
1004                 /* Instances always have the entry address */
1005                 dwarf_entrypc(sp_die, &pf->addr);
1006                 /* But in some case the entry address is 0 */
1007                 if (pf->addr == 0) {
1008                         pr_debug("%s has no entry PC. Skipped\n",
1009                                  dwarf_diename(sp_die));
1010                         param->retval = 0;
1011                 /* Real function */
1012                 } else if (pp->lazy_line)
1013                         param->retval = find_probe_point_lazy(sp_die, pf);
1014                 else {
1015                         skip_prologue(sp_die, pf);
1016                         pf->addr += pp->offset;
1017                         /* TODO: Check the address in this function */
1018                         param->retval = call_probe_finder(sp_die, pf);
1019                 }
1020         } else if (!probe_conf.no_inlines) {
1021                 /* Inlined function: search instances */
1022                 param->retval = die_walk_instances(sp_die,
1023                                         probe_point_inline_cb, (void *)pf);
1024                 /* This could be a non-existed inline definition */
1025                 if (param->retval == -ENOENT)
1026                         param->retval = 0;
1027         }
1028
1029         /* We need to find other candidates */
1030         if (strisglob(pp->function) && param->retval >= 0) {
1031                 param->retval = 0;      /* We have to clear the result */
1032                 return DWARF_CB_OK;
1033         }
1034
1035         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1036 }
1037
1038 static int find_probe_point_by_func(struct probe_finder *pf)
1039 {
1040         struct dwarf_callback_param _param = {.data = (void *)pf,
1041                                               .retval = 0};
1042         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1043         return _param.retval;
1044 }
1045
1046 struct pubname_callback_param {
1047         char *function;
1048         char *file;
1049         Dwarf_Die *cu_die;
1050         Dwarf_Die *sp_die;
1051         int found;
1052 };
1053
1054 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1055 {
1056         struct pubname_callback_param *param = data;
1057
1058         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1059                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1060                         return DWARF_CB_OK;
1061
1062                 if (die_match_name(param->sp_die, param->function)) {
1063                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1064                                 return DWARF_CB_OK;
1065
1066                         if (param->file &&
1067                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1068                                 return DWARF_CB_OK;
1069
1070                         param->found = 1;
1071                         return DWARF_CB_ABORT;
1072                 }
1073         }
1074
1075         return DWARF_CB_OK;
1076 }
1077
1078 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1079                                   struct probe_finder *pf)
1080 {
1081         struct perf_probe_point *pp = &pf->pev->point;
1082         Dwarf_Off off, noff;
1083         size_t cuhl;
1084         Dwarf_Die *diep;
1085         int ret = 0;
1086
1087         off = 0;
1088         pf->lcache = intlist__new(NULL);
1089         if (!pf->lcache)
1090                 return -ENOMEM;
1091
1092         /* Fastpath: lookup by function name from .debug_pubnames section */
1093         if (pp->function && !strisglob(pp->function)) {
1094                 struct pubname_callback_param pubname_param = {
1095                         .function = pp->function,
1096                         .file     = pp->file,
1097                         .cu_die   = &pf->cu_die,
1098                         .sp_die   = &pf->sp_die,
1099                         .found    = 0,
1100                 };
1101                 struct dwarf_callback_param probe_param = {
1102                         .data = pf,
1103                 };
1104
1105                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1106                                   &pubname_param, 0);
1107                 if (pubname_param.found) {
1108                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1109                         if (ret)
1110                                 goto found;
1111                 }
1112         }
1113
1114         /* Loop on CUs (Compilation Unit) */
1115         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1116                 /* Get the DIE(Debugging Information Entry) of this CU */
1117                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1118                 if (!diep)
1119                         continue;
1120
1121                 /* Check if target file is included. */
1122                 if (pp->file)
1123                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1124                 else
1125                         pf->fname = NULL;
1126
1127                 if (!pp->file || pf->fname) {
1128                         if (pp->function)
1129                                 ret = find_probe_point_by_func(pf);
1130                         else if (pp->lazy_line)
1131                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1132                         else {
1133                                 pf->lno = pp->line;
1134                                 ret = find_probe_point_by_line(pf);
1135                         }
1136                         if (ret < 0)
1137                                 break;
1138                 }
1139                 off = noff;
1140         }
1141
1142 found:
1143         intlist__delete(pf->lcache);
1144         pf->lcache = NULL;
1145
1146         return ret;
1147 }
1148
1149 /* Find probe points from debuginfo */
1150 static int debuginfo__find_probes(struct debuginfo *dbg,
1151                                   struct probe_finder *pf)
1152 {
1153         int ret = 0;
1154         Elf *elf;
1155         GElf_Ehdr ehdr;
1156
1157         if (pf->cfi_eh || pf->cfi_dbg)
1158                 return debuginfo__find_probe_location(dbg, pf);
1159
1160         /* Get the call frame information from this dwarf */
1161         elf = dwarf_getelf(dbg->dbg);
1162         if (elf == NULL)
1163                 return -EINVAL;
1164
1165         if (gelf_getehdr(elf, &ehdr) == NULL)
1166                 return -EINVAL;
1167
1168         pf->machine = ehdr.e_machine;
1169
1170 #if _ELFUTILS_PREREQ(0, 142)
1171         do {
1172                 GElf_Shdr shdr;
1173
1174                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1175                     shdr.sh_type == SHT_PROGBITS)
1176                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1177
1178                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1179         } while (0);
1180 #endif
1181
1182         ret = debuginfo__find_probe_location(dbg, pf);
1183         return ret;
1184 }
1185
1186 struct local_vars_finder {
1187         struct probe_finder *pf;
1188         struct perf_probe_arg *args;
1189         bool vars;
1190         int max_args;
1191         int nargs;
1192         int ret;
1193 };
1194
1195 /* Collect available variables in this scope */
1196 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1197 {
1198         struct local_vars_finder *vf = data;
1199         struct probe_finder *pf = vf->pf;
1200         int tag;
1201
1202         tag = dwarf_tag(die_mem);
1203         if (tag == DW_TAG_formal_parameter ||
1204             (tag == DW_TAG_variable && vf->vars)) {
1205                 if (convert_variable_location(die_mem, vf->pf->addr,
1206                                               vf->pf->fb_ops, &pf->sp_die,
1207                                               pf->machine, NULL) == 0) {
1208                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1209                         if (vf->args[vf->nargs].var == NULL) {
1210                                 vf->ret = -ENOMEM;
1211                                 return DIE_FIND_CB_END;
1212                         }
1213                         pr_debug(" %s", vf->args[vf->nargs].var);
1214                         vf->nargs++;
1215                 }
1216         }
1217
1218         if (dwarf_haspc(die_mem, vf->pf->addr))
1219                 return DIE_FIND_CB_CONTINUE;
1220         else
1221                 return DIE_FIND_CB_SIBLING;
1222 }
1223
1224 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1225                              struct perf_probe_arg *args)
1226 {
1227         Dwarf_Die die_mem;
1228         int i;
1229         int n = 0;
1230         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1231                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1232
1233         for (i = 0; i < pf->pev->nargs; i++) {
1234                 /* var never be NULL */
1235                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1236                         vf.vars = true;
1237                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1238                         /* Copy normal argument */
1239                         args[n] = pf->pev->args[i];
1240                         n++;
1241                         continue;
1242                 }
1243                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1244                 vf.nargs = n;
1245                 /* Special local variables */
1246                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1247                                &die_mem);
1248                 pr_debug(" (%d)\n", vf.nargs - n);
1249                 if (vf.ret < 0)
1250                         return vf.ret;
1251                 n = vf.nargs;
1252         }
1253         return n;
1254 }
1255
1256 /* Add a found probe point into trace event list */
1257 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1258 {
1259         struct trace_event_finder *tf =
1260                         container_of(pf, struct trace_event_finder, pf);
1261         struct perf_probe_point *pp = &pf->pev->point;
1262         struct probe_trace_event *tev;
1263         struct perf_probe_arg *args = NULL;
1264         int ret, i;
1265
1266         /* Check number of tevs */
1267         if (tf->ntevs == tf->max_tevs) {
1268                 pr_warning("Too many( > %d) probe point found.\n",
1269                            tf->max_tevs);
1270                 return -ERANGE;
1271         }
1272         tev = &tf->tevs[tf->ntevs++];
1273
1274         /* Trace point should be converted from subprogram DIE */
1275         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1276                                      pp->retprobe, pp->function, &tev->point);
1277         if (ret < 0)
1278                 goto end;
1279
1280         tev->point.realname = strdup(dwarf_diename(sc_die));
1281         if (!tev->point.realname) {
1282                 ret = -ENOMEM;
1283                 goto end;
1284         }
1285
1286         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1287                  tev->point.offset);
1288
1289         /* Expand special probe argument if exist */
1290         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1291         if (args == NULL) {
1292                 ret = -ENOMEM;
1293                 goto end;
1294         }
1295
1296         ret = expand_probe_args(sc_die, pf, args);
1297         if (ret < 0)
1298                 goto end;
1299
1300         tev->nargs = ret;
1301         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1302         if (tev->args == NULL) {
1303                 ret = -ENOMEM;
1304                 goto end;
1305         }
1306
1307         /* Find each argument */
1308         for (i = 0; i < tev->nargs; i++) {
1309                 pf->pvar = &args[i];
1310                 pf->tvar = &tev->args[i];
1311                 /* Variable should be found from scope DIE */
1312                 ret = find_variable(sc_die, pf);
1313                 if (ret != 0)
1314                         break;
1315         }
1316
1317 end:
1318         if (ret) {
1319                 clear_probe_trace_event(tev);
1320                 tf->ntevs--;
1321         }
1322         free(args);
1323         return ret;
1324 }
1325
1326 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1327 int debuginfo__find_trace_events(struct debuginfo *dbg,
1328                                  struct perf_probe_event *pev,
1329                                  struct probe_trace_event **tevs)
1330 {
1331         struct trace_event_finder tf = {
1332                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1333                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1334         int ret, i;
1335
1336         /* Allocate result tevs array */
1337         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1338         if (*tevs == NULL)
1339                 return -ENOMEM;
1340
1341         tf.tevs = *tevs;
1342         tf.ntevs = 0;
1343
1344         ret = debuginfo__find_probes(dbg, &tf.pf);
1345         if (ret < 0) {
1346                 for (i = 0; i < tf.ntevs; i++)
1347                         clear_probe_trace_event(&tf.tevs[i]);
1348                 zfree(tevs);
1349                 return ret;
1350         }
1351
1352         return (ret < 0) ? ret : tf.ntevs;
1353 }
1354
1355 /* Collect available variables in this scope */
1356 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1357 {
1358         struct available_var_finder *af = data;
1359         struct variable_list *vl;
1360         struct strbuf buf = STRBUF_INIT;
1361         int tag, ret;
1362
1363         vl = &af->vls[af->nvls - 1];
1364
1365         tag = dwarf_tag(die_mem);
1366         if (tag == DW_TAG_formal_parameter ||
1367             tag == DW_TAG_variable) {
1368                 ret = convert_variable_location(die_mem, af->pf.addr,
1369                                                 af->pf.fb_ops, &af->pf.sp_die,
1370                                                 af->pf.machine, NULL);
1371                 if (ret == 0 || ret == -ERANGE) {
1372                         int ret2;
1373                         bool externs = !af->child;
1374
1375                         if (strbuf_init(&buf, 64) < 0)
1376                                 goto error;
1377
1378                         if (probe_conf.show_location_range) {
1379                                 if (!externs)
1380                                         ret2 = strbuf_add(&buf,
1381                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1382                                 else
1383                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1384                                 if (ret2)
1385                                         goto error;
1386                         }
1387
1388                         ret2 = die_get_varname(die_mem, &buf);
1389
1390                         if (!ret2 && probe_conf.show_location_range &&
1391                                 !externs) {
1392                                 if (strbuf_addch(&buf, '\t') < 0)
1393                                         goto error;
1394                                 ret2 = die_get_var_range(&af->pf.sp_die,
1395                                                         die_mem, &buf);
1396                         }
1397
1398                         pr_debug("Add new var: %s\n", buf.buf);
1399                         if (ret2 == 0) {
1400                                 strlist__add(vl->vars,
1401                                         strbuf_detach(&buf, NULL));
1402                         }
1403                         strbuf_release(&buf);
1404                 }
1405         }
1406
1407         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1408                 return DIE_FIND_CB_CONTINUE;
1409         else
1410                 return DIE_FIND_CB_SIBLING;
1411 error:
1412         strbuf_release(&buf);
1413         pr_debug("Error in strbuf\n");
1414         return DIE_FIND_CB_END;
1415 }
1416
1417 /* Add a found vars into available variables list */
1418 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1419 {
1420         struct available_var_finder *af =
1421                         container_of(pf, struct available_var_finder, pf);
1422         struct perf_probe_point *pp = &pf->pev->point;
1423         struct variable_list *vl;
1424         Dwarf_Die die_mem;
1425         int ret;
1426
1427         /* Check number of tevs */
1428         if (af->nvls == af->max_vls) {
1429                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1430                 return -ERANGE;
1431         }
1432         vl = &af->vls[af->nvls++];
1433
1434         /* Trace point should be converted from subprogram DIE */
1435         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1436                                      pp->retprobe, pp->function, &vl->point);
1437         if (ret < 0)
1438                 return ret;
1439
1440         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1441                  vl->point.offset);
1442
1443         /* Find local variables */
1444         vl->vars = strlist__new(NULL, NULL);
1445         if (vl->vars == NULL)
1446                 return -ENOMEM;
1447         af->child = true;
1448         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1449
1450         /* Find external variables */
1451         if (!probe_conf.show_ext_vars)
1452                 goto out;
1453         /* Don't need to search child DIE for external vars. */
1454         af->child = false;
1455         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1456
1457 out:
1458         if (strlist__empty(vl->vars)) {
1459                 strlist__delete(vl->vars);
1460                 vl->vars = NULL;
1461         }
1462
1463         return ret;
1464 }
1465
1466 /*
1467  * Find available variables at given probe point
1468  * Return the number of found probe points. Return 0 if there is no
1469  * matched probe point. Return <0 if an error occurs.
1470  */
1471 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1472                                       struct perf_probe_event *pev,
1473                                       struct variable_list **vls)
1474 {
1475         struct available_var_finder af = {
1476                         .pf = {.pev = pev, .callback = add_available_vars},
1477                         .mod = dbg->mod,
1478                         .max_vls = probe_conf.max_probes};
1479         int ret;
1480
1481         /* Allocate result vls array */
1482         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1483         if (*vls == NULL)
1484                 return -ENOMEM;
1485
1486         af.vls = *vls;
1487         af.nvls = 0;
1488
1489         ret = debuginfo__find_probes(dbg, &af.pf);
1490         if (ret < 0) {
1491                 /* Free vlist for error */
1492                 while (af.nvls--) {
1493                         zfree(&af.vls[af.nvls].point.symbol);
1494                         strlist__delete(af.vls[af.nvls].vars);
1495                 }
1496                 zfree(vls);
1497                 return ret;
1498         }
1499
1500         return (ret < 0) ? ret : af.nvls;
1501 }
1502
1503 /* For the kernel module, we need a special code to get a DIE */
1504 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1505 {
1506         int n, i;
1507         Elf32_Word shndx;
1508         Elf_Scn *scn;
1509         Elf *elf;
1510         GElf_Shdr mem, *shdr;
1511         const char *p;
1512
1513         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1514         if (!elf)
1515                 return -EINVAL;
1516
1517         /* Get the number of relocations */
1518         n = dwfl_module_relocations(dbg->mod);
1519         if (n < 0)
1520                 return -ENOENT;
1521         /* Search the relocation related .text section */
1522         for (i = 0; i < n; i++) {
1523                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1524                 if (strcmp(p, ".text") == 0) {
1525                         /* OK, get the section header */
1526                         scn = elf_getscn(elf, shndx);
1527                         if (!scn)
1528                                 return -ENOENT;
1529                         shdr = gelf_getshdr(scn, &mem);
1530                         if (!shdr)
1531                                 return -ENOENT;
1532                         *offs = shdr->sh_addr;
1533                 }
1534         }
1535         return 0;
1536 }
1537
1538 /* Reverse search */
1539 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1540                                 struct perf_probe_point *ppt)
1541 {
1542         Dwarf_Die cudie, spdie, indie;
1543         Dwarf_Addr _addr = 0, baseaddr = 0;
1544         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1545         int baseline = 0, lineno = 0, ret = 0;
1546         bool reloc = false;
1547
1548 retry:
1549         /* Find cu die */
1550         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1551                 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1552                         addr += baseaddr;
1553                         reloc = true;
1554                         goto retry;
1555                 }
1556                 pr_warning("Failed to find debug information for address %lx\n",
1557                            addr);
1558                 ret = -EINVAL;
1559                 goto end;
1560         }
1561
1562         /* Find a corresponding line (filename and lineno) */
1563         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1564         /* Don't care whether it failed or not */
1565
1566         /* Find a corresponding function (name, baseline and baseaddr) */
1567         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1568                 /* Get function entry information */
1569                 func = basefunc = dwarf_diename(&spdie);
1570                 if (!func ||
1571                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1572                     dwarf_decl_line(&spdie, &baseline) != 0) {
1573                         lineno = 0;
1574                         goto post;
1575                 }
1576
1577                 fname = dwarf_decl_file(&spdie);
1578                 if (addr == (unsigned long)baseaddr) {
1579                         /* Function entry - Relative line number is 0 */
1580                         lineno = baseline;
1581                         goto post;
1582                 }
1583
1584                 /* Track down the inline functions step by step */
1585                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1586                                                 &indie)) {
1587                         /* There is an inline function */
1588                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1589                             _addr == addr) {
1590                                 /*
1591                                  * addr is at an inline function entry.
1592                                  * In this case, lineno should be the call-site
1593                                  * line number. (overwrite lineinfo)
1594                                  */
1595                                 lineno = die_get_call_lineno(&indie);
1596                                 fname = die_get_call_file(&indie);
1597                                 break;
1598                         } else {
1599                                 /*
1600                                  * addr is in an inline function body.
1601                                  * Since lineno points one of the lines
1602                                  * of the inline function, baseline should
1603                                  * be the entry line of the inline function.
1604                                  */
1605                                 tmp = dwarf_diename(&indie);
1606                                 if (!tmp ||
1607                                     dwarf_decl_line(&indie, &baseline) != 0)
1608                                         break;
1609                                 func = tmp;
1610                                 spdie = indie;
1611                         }
1612                 }
1613                 /* Verify the lineno and baseline are in a same file */
1614                 tmp = dwarf_decl_file(&spdie);
1615                 if (!tmp || strcmp(tmp, fname) != 0)
1616                         lineno = 0;
1617         }
1618
1619 post:
1620         /* Make a relative line number or an offset */
1621         if (lineno)
1622                 ppt->line = lineno - baseline;
1623         else if (basefunc) {
1624                 ppt->offset = addr - (unsigned long)baseaddr;
1625                 func = basefunc;
1626         }
1627
1628         /* Duplicate strings */
1629         if (func) {
1630                 ppt->function = strdup(func);
1631                 if (ppt->function == NULL) {
1632                         ret = -ENOMEM;
1633                         goto end;
1634                 }
1635         }
1636         if (fname) {
1637                 ppt->file = strdup(fname);
1638                 if (ppt->file == NULL) {
1639                         zfree(&ppt->function);
1640                         ret = -ENOMEM;
1641                         goto end;
1642                 }
1643         }
1644 end:
1645         if (ret == 0 && (fname || func))
1646                 ret = 1;        /* Found a point */
1647         return ret;
1648 }
1649
1650 /* Add a line and store the src path */
1651 static int line_range_add_line(const char *src, unsigned int lineno,
1652                                struct line_range *lr)
1653 {
1654         /* Copy source path */
1655         if (!lr->path) {
1656                 lr->path = strdup(src);
1657                 if (lr->path == NULL)
1658                         return -ENOMEM;
1659         }
1660         return intlist__add(lr->line_list, lineno);
1661 }
1662
1663 static int line_range_walk_cb(const char *fname, int lineno,
1664                               Dwarf_Addr addr __maybe_unused,
1665                               void *data)
1666 {
1667         struct line_finder *lf = data;
1668         int err;
1669
1670         if ((strtailcmp(fname, lf->fname) != 0) ||
1671             (lf->lno_s > lineno || lf->lno_e < lineno))
1672                 return 0;
1673
1674         err = line_range_add_line(fname, lineno, lf->lr);
1675         if (err < 0 && err != -EEXIST)
1676                 return err;
1677
1678         return 0;
1679 }
1680
1681 /* Find line range from its line number */
1682 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1683 {
1684         int ret;
1685
1686         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1687
1688         /* Update status */
1689         if (ret >= 0)
1690                 if (!intlist__empty(lf->lr->line_list))
1691                         ret = lf->found = 1;
1692                 else
1693                         ret = 0;        /* Lines are not found */
1694         else {
1695                 zfree(&lf->lr->path);
1696         }
1697         return ret;
1698 }
1699
1700 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1701 {
1702         int ret = find_line_range_by_line(in_die, data);
1703
1704         /*
1705          * We have to check all instances of inlined function, because
1706          * some execution paths can be optimized out depends on the
1707          * function argument of instances. However, if an error occurs,
1708          * it should be handled by the caller.
1709          */
1710         return ret < 0 ? ret : 0;
1711 }
1712
1713 /* Search function definition from function name */
1714 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1715 {
1716         struct dwarf_callback_param *param = data;
1717         struct line_finder *lf = param->data;
1718         struct line_range *lr = lf->lr;
1719
1720         /* Check declared file */
1721         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1722                 return DWARF_CB_OK;
1723
1724         if (die_is_func_def(sp_die) &&
1725             die_match_name(sp_die, lr->function)) {
1726                 lf->fname = dwarf_decl_file(sp_die);
1727                 dwarf_decl_line(sp_die, &lr->offset);
1728                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1729                 lf->lno_s = lr->offset + lr->start;
1730                 if (lf->lno_s < 0)      /* Overflow */
1731                         lf->lno_s = INT_MAX;
1732                 lf->lno_e = lr->offset + lr->end;
1733                 if (lf->lno_e < 0)      /* Overflow */
1734                         lf->lno_e = INT_MAX;
1735                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1736                 lr->start = lf->lno_s;
1737                 lr->end = lf->lno_e;
1738                 if (!die_is_func_instance(sp_die))
1739                         param->retval = die_walk_instances(sp_die,
1740                                                 line_range_inline_cb, lf);
1741                 else
1742                         param->retval = find_line_range_by_line(sp_die, lf);
1743                 return DWARF_CB_ABORT;
1744         }
1745         return DWARF_CB_OK;
1746 }
1747
1748 static int find_line_range_by_func(struct line_finder *lf)
1749 {
1750         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1751         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1752         return param.retval;
1753 }
1754
1755 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1756 {
1757         struct line_finder lf = {.lr = lr, .found = 0};
1758         int ret = 0;
1759         Dwarf_Off off = 0, noff;
1760         size_t cuhl;
1761         Dwarf_Die *diep;
1762         const char *comp_dir;
1763
1764         /* Fastpath: lookup by function name from .debug_pubnames section */
1765         if (lr->function) {
1766                 struct pubname_callback_param pubname_param = {
1767                         .function = lr->function, .file = lr->file,
1768                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1769                 struct dwarf_callback_param line_range_param = {
1770                         .data = (void *)&lf, .retval = 0};
1771
1772                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1773                                   &pubname_param, 0);
1774                 if (pubname_param.found) {
1775                         line_range_search_cb(&lf.sp_die, &line_range_param);
1776                         if (lf.found)
1777                                 goto found;
1778                 }
1779         }
1780
1781         /* Loop on CUs (Compilation Unit) */
1782         while (!lf.found && ret >= 0) {
1783                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1784                                  NULL, NULL, NULL) != 0)
1785                         break;
1786
1787                 /* Get the DIE(Debugging Information Entry) of this CU */
1788                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1789                 if (!diep)
1790                         continue;
1791
1792                 /* Check if target file is included. */
1793                 if (lr->file)
1794                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1795                 else
1796                         lf.fname = 0;
1797
1798                 if (!lr->file || lf.fname) {
1799                         if (lr->function)
1800                                 ret = find_line_range_by_func(&lf);
1801                         else {
1802                                 lf.lno_s = lr->start;
1803                                 lf.lno_e = lr->end;
1804                                 ret = find_line_range_by_line(NULL, &lf);
1805                         }
1806                 }
1807                 off = noff;
1808         }
1809
1810 found:
1811         /* Store comp_dir */
1812         if (lf.found) {
1813                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1814                 if (comp_dir) {
1815                         lr->comp_dir = strdup(comp_dir);
1816                         if (!lr->comp_dir)
1817                                 ret = -ENOMEM;
1818                 }
1819         }
1820
1821         pr_debug("path: %s\n", lr->path);
1822         return (ret < 0) ? ret : lf.found;
1823 }
1824
1825 /*
1826  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1827  * and chop off leading directories that do not exist. Result is passed back as
1828  * a newly allocated path on success.
1829  * Return 0 if file was found and readable, -errno otherwise.
1830  */
1831 int get_real_path(const char *raw_path, const char *comp_dir,
1832                          char **new_path)
1833 {
1834         const char *prefix = symbol_conf.source_prefix;
1835
1836         if (!prefix) {
1837                 if (raw_path[0] != '/' && comp_dir)
1838                         /* If not an absolute path, try to use comp_dir */
1839                         prefix = comp_dir;
1840                 else {
1841                         if (access(raw_path, R_OK) == 0) {
1842                                 *new_path = strdup(raw_path);
1843                                 return *new_path ? 0 : -ENOMEM;
1844                         } else
1845                                 return -errno;
1846                 }
1847         }
1848
1849         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1850         if (!*new_path)
1851                 return -ENOMEM;
1852
1853         for (;;) {
1854                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1855
1856                 if (access(*new_path, R_OK) == 0)
1857                         return 0;
1858
1859                 if (!symbol_conf.source_prefix) {
1860                         /* In case of searching comp_dir, don't retry */
1861                         zfree(new_path);
1862                         return -errno;
1863                 }
1864
1865                 switch (errno) {
1866                 case ENAMETOOLONG:
1867                 case ENOENT:
1868                 case EROFS:
1869                 case EFAULT:
1870                         raw_path = strchr(++raw_path, '/');
1871                         if (!raw_path) {
1872                                 zfree(new_path);
1873                                 return -ENOENT;
1874                         }
1875                         continue;
1876
1877                 default:
1878                         zfree(new_path);
1879                         return -errno;
1880                 }
1881         }
1882 }