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 prefix;
 302
 303         /* TODO: check all types */
 304         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 305             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 306                 /* Non string type is OK */
 307                 /* and respect signedness/hexadecimal 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                 prefix = 'u';
 370         else if (cast && (strcmp(cast, "s") == 0))
 371                 prefix = 's';
 372         else if (cast && (strcmp(cast, "x") == 0) &&
 373                  probe_type_is_available(PROBE_TYPE_X))
 374                 prefix = 'x';
 375         else
 376                 prefix = die_is_signed_type(&type) ? 's' :
 377                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 378
 379         ret = dwarf_bytesize(&type);
 380         if (ret <= 0)
 381                 /* No size ... try to use default type */
 382                 return 0;
 383         ret = BYTES_TO_BITS(ret);
 384
 385         /* Check the bitwidth */
 386         if (ret > MAX_BASIC_TYPE_BITS) {
 387                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 388                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 389                 ret = MAX_BASIC_TYPE_BITS;
 390         }
 391         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 392
 393 formatted:
 394         if (ret < 0 || ret >= 16) {
 395                 if (ret >= 16)
 396                         ret = -E2BIG;
 397                 pr_warning("Failed to convert variable type: %s\n",
 398                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 399                 return ret;
 400         }
 401         tvar->type = strdup(buf);
 402         if (tvar->type == NULL)
 403                 return -ENOMEM;
 404         return 0;
 405 }
 406
 407 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 408                                     struct perf_probe_arg_field *field,
 409                                     struct probe_trace_arg_ref **ref_ptr,
 410                                     Dwarf_Die *die_mem)
 411 {
 412         struct probe_trace_arg_ref *ref = *ref_ptr;
 413         Dwarf_Die type;
 414         Dwarf_Word offs;
 415         int ret, tag;
 416
 417         pr_debug("converting %s in %s\n", field->name, varname);
 418         if (die_get_real_type(vr_die, &type) == NULL) {
 419                 pr_warning("Failed to get the type of %s.\n", varname);
 420                 return -ENOENT;
 421         }
 422         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 423         tag = dwarf_tag(&type);
 424
 425         if (field->name[0] == '[' &&
 426             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 427                 if (field->next)
 428                         /* Save original type for next field */
 429                         memcpy(die_mem, &type, sizeof(*die_mem));
 430                 /* Get the type of this array */
 431                 if (die_get_real_type(&type, &type) == NULL) {
 432                         pr_warning("Failed to get the type of %s.\n", varname);
 433                         return -ENOENT;
 434                 }
 435                 pr_debug2("Array real type: (%x)\n",
 436                          (unsigned)dwarf_dieoffset(&type));
 437                 if (tag == DW_TAG_pointer_type) {
 438                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 439                         if (ref == NULL)
 440                                 return -ENOMEM;
 441                         if (*ref_ptr)
 442                                 (*ref_ptr)->next = ref;
 443                         else
 444                                 *ref_ptr = ref;
 445                 }
 446                 ref->offset += dwarf_bytesize(&type) * field->index;
 447                 if (!field->next)
 448                         /* Save vr_die for converting types */
 449                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 450                 goto next;
 451         } else if (tag == DW_TAG_pointer_type) {
 452                 /* Check the pointer and dereference */
 453                 if (!field->ref) {
 454                         pr_err("Semantic error: %s must be referred by '->'\n",
 455                                field->name);
 456                         return -EINVAL;
 457                 }
 458                 /* Get the type pointed by this pointer */
 459                 if (die_get_real_type(&type, &type) == NULL) {
 460                         pr_warning("Failed to get the type of %s.\n", varname);
 461                         return -ENOENT;
 462                 }
 463                 /* Verify it is a data structure  */
 464                 tag = dwarf_tag(&type);
 465                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 466                         pr_warning("%s is not a data structure nor an union.\n",
 467                                    varname);
 468                         return -EINVAL;
 469                 }
 470
 471                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 472                 if (ref == NULL)
 473                         return -ENOMEM;
 474                 if (*ref_ptr)
 475                         (*ref_ptr)->next = ref;
 476                 else
 477                         *ref_ptr = ref;
 478         } else {
 479                 /* Verify it is a data structure  */
 480                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 481                         pr_warning("%s is not a data structure nor an union.\n",
 482                                    varname);
 483                         return -EINVAL;
 484                 }
 485                 if (field->name[0] == '[') {
 486                         pr_err("Semantic error: %s is not a pointer"
 487                                " nor array.\n", varname);
 488                         return -EINVAL;
 489                 }
 490                 /* While prcessing unnamed field, we don't care about this */
 491                 if (field->ref && dwarf_diename(vr_die)) {
 492                         pr_err("Semantic error: %s must be referred by '.'\n",
 493                                field->name);
 494                         return -EINVAL;
 495                 }
 496                 if (!ref) {
 497                         pr_warning("Structure on a register is not "
 498                                    "supported yet.\n");
 499                         return -ENOTSUP;
 500                 }
 501         }
 502
 503         if (die_find_member(&type, field->name, die_mem) == NULL) {
 504                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 505                            dwarf_diename(&type), field->name);
 506                 return -EINVAL;
 507         }
 508
 509         /* Get the offset of the field */
 510         if (tag == DW_TAG_union_type) {
 511                 offs = 0;
 512         } else {
 513                 ret = die_get_data_member_location(die_mem, &offs);
 514                 if (ret < 0) {
 515                         pr_warning("Failed to get the offset of %s.\n",
 516                                    field->name);
 517                         return ret;
 518                 }
 519         }
 520         ref->offset += (long)offs;
 521
 522         /* If this member is unnamed, we need to reuse this field */
 523         if (!dwarf_diename(die_mem))
 524                 return convert_variable_fields(die_mem, varname, field,
 525                                                 &ref, die_mem);
 526
 527 next:
 528         /* Converting next field */
 529         if (field->next)
 530                 return convert_variable_fields(die_mem, field->name,
 531                                         field->next, &ref, die_mem);
 532         else
 533                 return 0;
 534 }
 535
 536 /* Show a variables in kprobe event format */
 537 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 538 {
 539         Dwarf_Die die_mem;
 540         int ret;
 541
 542         pr_debug("Converting variable %s into trace event.\n",
 543                  dwarf_diename(vr_die));
 544
 545         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 546                                         &pf->sp_die, pf->tvar);
 547         if (ret == -ENOENT || ret == -EINVAL) {
 548                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 549                        " Perhaps it has been optimized out.\n"
 550                        " Use -V with the --range option to show '%s' location range.\n",
 551                        pf->pvar->var, pf->pvar->var);
 552         } else if (ret == -ENOTSUP)
 553                 pr_err("Sorry, we don't support this variable location yet.\n");
 554         else if (ret == 0 && pf->pvar->field) {
 555                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 556                                               pf->pvar->field, &pf->tvar->ref,
 557                                               &die_mem);
 558                 vr_die = &die_mem;
 559         }
 560         if (ret == 0)
 561                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 562         /* *expr will be cached in libdw. Don't free it. */
 563         return ret;
 564 }
 565
 566 /* Find a variable in a scope DIE */
 567 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 568 {
 569         Dwarf_Die vr_die;
 570         char *buf, *ptr;
 571         int ret = 0;
 572
 573         /* Copy raw parameters */
 574         if (!is_c_varname(pf->pvar->var))
 575                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 576
 577         if (pf->pvar->name)
 578                 pf->tvar->name = strdup(pf->pvar->name);
 579         else {
 580                 buf = synthesize_perf_probe_arg(pf->pvar);
 581                 if (!buf)
 582                         return -ENOMEM;
 583                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 584                 if (ptr)
 585                         *ptr = '_';
 586                 pf->tvar->name = buf;
 587         }
 588         if (pf->tvar->name == NULL)
 589                 return -ENOMEM;
 590
 591         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 592         /* Search child die for local variables and parameters. */
 593         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 594                 /* Search again in global variables */
 595                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 596                                                 0, &vr_die)) {
 597                         pr_warning("Failed to find '%s' in this function.\n",
 598                                    pf->pvar->var);
 599                         ret = -ENOENT;
 600                 }
 601         }
 602         if (ret >= 0)
 603                 ret = convert_variable(&vr_die, pf);
 604
 605         return ret;
 606 }
 607
 608 /* Convert subprogram DIE to trace point */
 609 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 610                                   Dwarf_Addr paddr, bool retprobe,
 611                                   const char *function,
 612                                   struct probe_trace_point *tp)
 613 {
 614         Dwarf_Addr eaddr, highaddr;
 615         GElf_Sym sym;
 616         const char *symbol;
 617
 618         /* Verify the address is correct */
 619         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 620                 pr_warning("Failed to get entry address of %s\n",
 621                            dwarf_diename(sp_die));
 622                 return -ENOENT;
 623         }
 624         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 625                 pr_warning("Failed to get end address of %s\n",
 626                            dwarf_diename(sp_die));
 627                 return -ENOENT;
 628         }
 629         if (paddr > highaddr) {
 630                 pr_warning("Offset specified is greater than size of %s\n",
 631                            dwarf_diename(sp_die));
 632                 return -EINVAL;
 633         }
 634
 635         symbol = dwarf_diename(sp_die);
 636         if (!symbol) {
 637                 /* Try to get the symbol name from symtab */
 638                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 639                 if (!symbol) {
 640                         pr_warning("Failed to find symbol at 0x%lx\n",
 641                                    (unsigned long)paddr);
 642                         return -ENOENT;
 643                 }
 644                 eaddr = sym.st_value;
 645         }
 646         tp->offset = (unsigned long)(paddr - eaddr);
 647         tp->address = (unsigned long)paddr;
 648         tp->symbol = strdup(symbol);
 649         if (!tp->symbol)
 650                 return -ENOMEM;
 651
 652         /* Return probe must be on the head of a subprogram */
 653         if (retprobe) {
 654                 if (eaddr != paddr) {
 655                         pr_warning("Failed to find \"%s%%return\",\n"
 656                                    " because %s is an inlined function and"
 657                                    " has no return point.\n", function,
 658                                    function);
 659                         return -EINVAL;
 660                 }
 661                 tp->retprobe = true;
 662         }
 663
 664         return 0;
 665 }
 666
 667 /* Call probe_finder callback with scope DIE */
 668 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 669 {
 670         Dwarf_Attribute fb_attr;
 671         Dwarf_Frame *frame = NULL;
 672         size_t nops;
 673         int ret;
 674
 675         if (!sc_die) {
 676                 pr_err("Caller must pass a scope DIE. Program error.\n");
 677                 return -EINVAL;
 678         }
 679
 680         /* If not a real subprogram, find a real one */
 681         if (!die_is_func_def(sc_die)) {
 682                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 683                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 684                                 pr_warning("Ignoring tail call from %s\n",
 685                                                 dwarf_diename(&pf->sp_die));
 686                                 return 0;
 687                         } else {
 688                                 pr_warning("Failed to find probe point in any "
 689                                            "functions.\n");
 690                                 return -ENOENT;
 691                         }
 692                 }
 693         } else
 694                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 695
 696         /* Get the frame base attribute/ops from subprogram */
 697         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 698         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 699         if (ret <= 0 || nops == 0) {
 700                 pf->fb_ops = NULL;
 701 #if _ELFUTILS_PREREQ(0, 142)
 702         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 703                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 704                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 705                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 706                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 707                         pr_warning("Failed to get call frame on 0x%jx\n",
 708                                    (uintmax_t)pf->addr);
 709                         free(frame);
 710                         return -ENOENT;
 711                 }
 712 #endif
 713         }
 714
 715         /* Call finder's callback handler */
 716         ret = pf->callback(sc_die, pf);
 717
 718         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 719         free(frame);
 720         pf->fb_ops = NULL;
 721
 722         return ret;
 723 }
 724
 725 struct find_scope_param {
 726         const char *function;
 727         const char *file;
 728         int line;
 729         int diff;
 730         Dwarf_Die *die_mem;
 731         bool found;
 732 };
 733
 734 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 735 {
 736         struct find_scope_param *fsp = data;
 737         const char *file;
 738         int lno;
 739
 740         /* Skip if declared file name does not match */
 741         if (fsp->file) {
 742                 file = dwarf_decl_file(fn_die);
 743                 if (!file || strcmp(fsp->file, file) != 0)
 744                         return 0;
 745         }
 746         /* If the function name is given, that's what user expects */
 747         if (fsp->function) {
 748                 if (die_match_name(fn_die, fsp->function)) {
 749                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 750                         fsp->found = true;
 751                         return 1;
 752                 }
 753         } else {
 754                 /* With the line number, find the nearest declared DIE */
 755                 dwarf_decl_line(fn_die, &lno);
 756                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 757                         /* Keep a candidate and continue */
 758                         fsp->diff = fsp->line - lno;
 759                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 760                         fsp->found = true;
 761                 }
 762         }
 763         return 0;
 764 }
 765
 766 /* Find an appropriate scope fits to given conditions */
 767 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 768 {
 769         struct find_scope_param fsp = {
 770                 .function = pf->pev->point.function,
 771                 .file = pf->fname,
 772                 .line = pf->lno,
 773                 .diff = INT_MAX,
 774                 .die_mem = die_mem,
 775                 .found = false,
 776         };
 777
 778         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 779
 780         return fsp.found ? die_mem : NULL;
 781 }
 782
 783 static int probe_point_line_walker(const char *fname, int lineno,
 784                                    Dwarf_Addr addr, void *data)
 785 {
 786         struct probe_finder *pf = data;
 787         Dwarf_Die *sc_die, die_mem;
 788         int ret;
 789
 790         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 791                 return 0;
 792
 793         pf->addr = addr;
 794         sc_die = find_best_scope(pf, &die_mem);
 795         if (!sc_die) {
 796                 pr_warning("Failed to find scope of probe point.\n");
 797                 return -ENOENT;
 798         }
 799
 800         ret = call_probe_finder(sc_die, pf);
 801
 802         /* Continue if no error, because the line will be in inline function */
 803         return ret < 0 ? ret : 0;
 804 }
 805
 806 /* Find probe point from its line number */
 807 static int find_probe_point_by_line(struct probe_finder *pf)
 808 {
 809         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 810 }
 811
 812 /* Find lines which match lazy pattern */
 813 static int find_lazy_match_lines(struct intlist *list,
 814                                  const char *fname, const char *pat)
 815 {
 816         FILE *fp;
 817         char *line = NULL;
 818         size_t line_len;
 819         ssize_t len;
 820         int count = 0, linenum = 1;
 821         char sbuf[STRERR_BUFSIZE];
 822
 823         fp = fopen(fname, "r");
 824         if (!fp) {
 825                 pr_warning("Failed to open %s: %s\n", fname,
 826                            str_error_r(errno, sbuf, sizeof(sbuf)));
 827                 return -errno;
 828         }
 829
 830         while ((len = getline(&line, &line_len, fp)) > 0) {
 831
 832                 if (line[len - 1] == '\n')
 833                         line[len - 1] = '\0';
 834
 835                 if (strlazymatch(line, pat)) {
 836                         intlist__add(list, linenum);
 837                         count++;
 838                 }
 839                 linenum++;
 840         }
 841
 842         if (ferror(fp))
 843                 count = -errno;
 844         free(line);
 845         fclose(fp);
 846
 847         if (count == 0)
 848                 pr_debug("No matched lines found in %s.\n", fname);
 849         return count;
 850 }
 851
 852 static int probe_point_lazy_walker(const char *fname, int lineno,
 853                                    Dwarf_Addr addr, void *data)
 854 {
 855         struct probe_finder *pf = data;
 856         Dwarf_Die *sc_die, die_mem;
 857         int ret;
 858
 859         if (!intlist__has_entry(pf->lcache, lineno) ||
 860             strtailcmp(fname, pf->fname) != 0)
 861                 return 0;
 862
 863         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 864                  lineno, (unsigned long long)addr);
 865         pf->addr = addr;
 866         pf->lno = lineno;
 867         sc_die = find_best_scope(pf, &die_mem);
 868         if (!sc_die) {
 869                 pr_warning("Failed to find scope of probe point.\n");
 870                 return -ENOENT;
 871         }
 872
 873         ret = call_probe_finder(sc_die, pf);
 874
 875         /*
 876          * Continue if no error, because the lazy pattern will match
 877          * to other lines
 878          */
 879         return ret < 0 ? ret : 0;
 880 }
 881
 882 /* Find probe points from lazy pattern  */
 883 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 884 {
 885         int ret = 0;
 886         char *fpath;
 887
 888         if (intlist__empty(pf->lcache)) {
 889                 const char *comp_dir;
 890
 891                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 892                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 893                 if (ret < 0) {
 894                         pr_warning("Failed to find source file path.\n");
 895                         return ret;
 896                 }
 897
 898                 /* Matching lazy line pattern */
 899                 ret = find_lazy_match_lines(pf->lcache, fpath,
 900                                             pf->pev->point.lazy_line);
 901                 free(fpath);
 902                 if (ret <= 0)
 903                         return ret;
 904         }
 905
 906         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 907 }
 908
 909 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 910 {
 911         struct probe_finder *pf = data;
 912         struct perf_probe_point *pp = &pf->pev->point;
 913         Dwarf_Addr addr;
 914         int ret;
 915
 916         if (pp->lazy_line)
 917                 ret = find_probe_point_lazy(in_die, pf);
 918         else {
 919                 /* Get probe address */
 920                 if (dwarf_entrypc(in_die, &addr) != 0) {
 921                         pr_warning("Failed to get entry address of %s.\n",
 922                                    dwarf_diename(in_die));
 923                         return -ENOENT;
 924                 }
 925                 pf->addr = addr;
 926                 pf->addr += pp->offset;
 927                 pr_debug("found inline addr: 0x%jx\n",
 928                          (uintmax_t)pf->addr);
 929
 930                 ret = call_probe_finder(in_die, pf);
 931         }
 932
 933         return ret;
 934 }
 935
 936 /* Callback parameter with return value for libdw */
 937 struct dwarf_callback_param {
 938         void *data;
 939         int retval;
 940 };
 941
 942 /* Search function from function name */
 943 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 944 {
 945         struct dwarf_callback_param *param = data;
 946         struct probe_finder *pf = param->data;
 947         struct perf_probe_point *pp = &pf->pev->point;
 948
 949         /* Check tag and diename */
 950         if (!die_is_func_def(sp_die) ||
 951             !die_match_name(sp_die, pp->function))
 952                 return DWARF_CB_OK;
 953
 954         /* Check declared file */
 955         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 956                 return DWARF_CB_OK;
 957
 958         pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
 959         pf->fname = dwarf_decl_file(sp_die);
 960         if (pp->line) { /* Function relative line */
 961                 dwarf_decl_line(sp_die, &pf->lno);
 962                 pf->lno += pp->line;
 963                 param->retval = find_probe_point_by_line(pf);
 964         } else if (die_is_func_instance(sp_die)) {
 965                 /* Instances always have the entry address */
 966                 dwarf_entrypc(sp_die, &pf->addr);
 967                 /* Real function */
 968                 if (pp->lazy_line)
 969                         param->retval = find_probe_point_lazy(sp_die, pf);
 970                 else {
 971                         pf->addr += pp->offset;
 972                         /* TODO: Check the address in this function */
 973                         param->retval = call_probe_finder(sp_die, pf);
 974                 }
 975         } else if (!probe_conf.no_inlines) {
 976                 /* Inlined function: search instances */
 977                 param->retval = die_walk_instances(sp_die,
 978                                         probe_point_inline_cb, (void *)pf);
 979                 /* This could be a non-existed inline definition */
 980                 if (param->retval == -ENOENT && strisglob(pp->function))
 981                         param->retval = 0;
 982         }
 983
 984         /* We need to find other candidates */
 985         if (strisglob(pp->function) && param->retval >= 0) {
 986                 param->retval = 0;      /* We have to clear the result */
 987                 return DWARF_CB_OK;
 988         }
 989
 990         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 991 }
 992
 993 static int find_probe_point_by_func(struct probe_finder *pf)
 994 {
 995         struct dwarf_callback_param _param = {.data = (void *)pf,
 996                                               .retval = 0};
 997         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 998         return _param.retval;
 999 }
1000
1001 struct pubname_callback_param {
1002         char *function;
1003         char *file;
1004         Dwarf_Die *cu_die;
1005         Dwarf_Die *sp_die;
1006         int found;
1007 };
1008
1009 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1010 {
1011         struct pubname_callback_param *param = data;
1012
1013         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1014                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1015                         return DWARF_CB_OK;
1016
1017                 if (die_match_name(param->sp_die, param->function)) {
1018                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1019                                 return DWARF_CB_OK;
1020
1021                         if (param->file &&
1022                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1023                                 return DWARF_CB_OK;
1024
1025                         param->found = 1;
1026                         return DWARF_CB_ABORT;
1027                 }
1028         }
1029
1030         return DWARF_CB_OK;
1031 }
1032
1033 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1034                                   struct probe_finder *pf)
1035 {
1036         struct perf_probe_point *pp = &pf->pev->point;
1037         Dwarf_Off off, noff;
1038         size_t cuhl;
1039         Dwarf_Die *diep;
1040         int ret = 0;
1041
1042         off = 0;
1043         pf->lcache = intlist__new(NULL);
1044         if (!pf->lcache)
1045                 return -ENOMEM;
1046
1047         /* Fastpath: lookup by function name from .debug_pubnames section */
1048         if (pp->function && !strisglob(pp->function)) {
1049                 struct pubname_callback_param pubname_param = {
1050                         .function = pp->function,
1051                         .file     = pp->file,
1052                         .cu_die   = &pf->cu_die,
1053                         .sp_die   = &pf->sp_die,
1054                         .found    = 0,
1055                 };
1056                 struct dwarf_callback_param probe_param = {
1057                         .data = pf,
1058                 };
1059
1060                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1061                                   &pubname_param, 0);
1062                 if (pubname_param.found) {
1063                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1064                         if (ret)
1065                                 goto found;
1066                 }
1067         }
1068
1069         /* Loop on CUs (Compilation Unit) */
1070         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1071                 /* Get the DIE(Debugging Information Entry) of this CU */
1072                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1073                 if (!diep)
1074                         continue;
1075
1076                 /* Check if target file is included. */
1077                 if (pp->file)
1078                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1079                 else
1080                         pf->fname = NULL;
1081
1082                 if (!pp->file || pf->fname) {
1083                         if (pp->function)
1084                                 ret = find_probe_point_by_func(pf);
1085                         else if (pp->lazy_line)
1086                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1087                         else {
1088                                 pf->lno = pp->line;
1089                                 ret = find_probe_point_by_line(pf);
1090                         }
1091                         if (ret < 0)
1092                                 break;
1093                 }
1094                 off = noff;
1095         }
1096
1097 found:
1098         intlist__delete(pf->lcache);
1099         pf->lcache = NULL;
1100
1101         return ret;
1102 }
1103
1104 /* Find probe points from debuginfo */
1105 static int debuginfo__find_probes(struct debuginfo *dbg,
1106                                   struct probe_finder *pf)
1107 {
1108         int ret = 0;
1109
1110 #if _ELFUTILS_PREREQ(0, 142)
1111         Elf *elf;
1112         GElf_Ehdr ehdr;
1113         GElf_Shdr shdr;
1114
1115         if (pf->cfi_eh || pf->cfi_dbg)
1116                 return debuginfo__find_probe_location(dbg, pf);
1117
1118         /* Get the call frame information from this dwarf */
1119         elf = dwarf_getelf(dbg->dbg);
1120         if (elf == NULL)
1121                 return -EINVAL;
1122
1123         if (gelf_getehdr(elf, &ehdr) == NULL)
1124                 return -EINVAL;
1125
1126         if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1127             shdr.sh_type == SHT_PROGBITS)
1128                 pf->cfi_eh = dwarf_getcfi_elf(elf);
1129
1130         pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1131 #endif
1132
1133         ret = debuginfo__find_probe_location(dbg, pf);
1134         return ret;
1135 }
1136
1137 struct local_vars_finder {
1138         struct probe_finder *pf;
1139         struct perf_probe_arg *args;
1140         bool vars;
1141         int max_args;
1142         int nargs;
1143         int ret;
1144 };
1145
1146 /* Collect available variables in this scope */
1147 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1148 {
1149         struct local_vars_finder *vf = data;
1150         struct probe_finder *pf = vf->pf;
1151         int tag;
1152
1153         tag = dwarf_tag(die_mem);
1154         if (tag == DW_TAG_formal_parameter ||
1155             (tag == DW_TAG_variable && vf->vars)) {
1156                 if (convert_variable_location(die_mem, vf->pf->addr,
1157                                               vf->pf->fb_ops, &pf->sp_die,
1158                                               NULL) == 0) {
1159                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1160                         if (vf->args[vf->nargs].var == NULL) {
1161                                 vf->ret = -ENOMEM;
1162                                 return DIE_FIND_CB_END;
1163                         }
1164                         pr_debug(" %s", vf->args[vf->nargs].var);
1165                         vf->nargs++;
1166                 }
1167         }
1168
1169         if (dwarf_haspc(die_mem, vf->pf->addr))
1170                 return DIE_FIND_CB_CONTINUE;
1171         else
1172                 return DIE_FIND_CB_SIBLING;
1173 }
1174
1175 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1176                              struct perf_probe_arg *args)
1177 {
1178         Dwarf_Die die_mem;
1179         int i;
1180         int n = 0;
1181         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1182                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1183
1184         for (i = 0; i < pf->pev->nargs; i++) {
1185                 /* var never be NULL */
1186                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1187                         vf.vars = true;
1188                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1189                         /* Copy normal argument */
1190                         args[n] = pf->pev->args[i];
1191                         n++;
1192                         continue;
1193                 }
1194                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1195                 vf.nargs = n;
1196                 /* Special local variables */
1197                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1198                                &die_mem);
1199                 pr_debug(" (%d)\n", vf.nargs - n);
1200                 if (vf.ret < 0)
1201                         return vf.ret;
1202                 n = vf.nargs;
1203         }
1204         return n;
1205 }
1206
1207 /* Add a found probe point into trace event list */
1208 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1209 {
1210         struct trace_event_finder *tf =
1211                         container_of(pf, struct trace_event_finder, pf);
1212         struct perf_probe_point *pp = &pf->pev->point;
1213         struct probe_trace_event *tev;
1214         struct perf_probe_arg *args = NULL;
1215         int ret, i;
1216
1217         /* Check number of tevs */
1218         if (tf->ntevs == tf->max_tevs) {
1219                 pr_warning("Too many( > %d) probe point found.\n",
1220                            tf->max_tevs);
1221                 return -ERANGE;
1222         }
1223         tev = &tf->tevs[tf->ntevs++];
1224
1225         /* Trace point should be converted from subprogram DIE */
1226         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1227                                      pp->retprobe, pp->function, &tev->point);
1228         if (ret < 0)
1229                 goto end;
1230
1231         tev->point.realname = strdup(dwarf_diename(sc_die));
1232         if (!tev->point.realname) {
1233                 ret = -ENOMEM;
1234                 goto end;
1235         }
1236
1237         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1238                  tev->point.offset);
1239
1240         /* Expand special probe argument if exist */
1241         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1242         if (args == NULL) {
1243                 ret = -ENOMEM;
1244                 goto end;
1245         }
1246
1247         ret = expand_probe_args(sc_die, pf, args);
1248         if (ret < 0)
1249                 goto end;
1250
1251         tev->nargs = ret;
1252         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1253         if (tev->args == NULL) {
1254                 ret = -ENOMEM;
1255                 goto end;
1256         }
1257
1258         /* Find each argument */
1259         for (i = 0; i < tev->nargs; i++) {
1260                 pf->pvar = &args[i];
1261                 pf->tvar = &tev->args[i];
1262                 /* Variable should be found from scope DIE */
1263                 ret = find_variable(sc_die, pf);
1264                 if (ret != 0)
1265                         break;
1266         }
1267
1268 end:
1269         if (ret) {
1270                 clear_probe_trace_event(tev);
1271                 tf->ntevs--;
1272         }
1273         free(args);
1274         return ret;
1275 }
1276
1277 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1278 int debuginfo__find_trace_events(struct debuginfo *dbg,
1279                                  struct perf_probe_event *pev,
1280                                  struct probe_trace_event **tevs)
1281 {
1282         struct trace_event_finder tf = {
1283                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1284                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1285         int ret, i;
1286
1287         /* Allocate result tevs array */
1288         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1289         if (*tevs == NULL)
1290                 return -ENOMEM;
1291
1292         tf.tevs = *tevs;
1293         tf.ntevs = 0;
1294
1295         ret = debuginfo__find_probes(dbg, &tf.pf);
1296         if (ret < 0) {
1297                 for (i = 0; i < tf.ntevs; i++)
1298                         clear_probe_trace_event(&tf.tevs[i]);
1299                 zfree(tevs);
1300                 return ret;
1301         }
1302
1303         return (ret < 0) ? ret : tf.ntevs;
1304 }
1305
1306 /* Collect available variables in this scope */
1307 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1308 {
1309         struct available_var_finder *af = data;
1310         struct variable_list *vl;
1311         struct strbuf buf = STRBUF_INIT;
1312         int tag, ret;
1313
1314         vl = &af->vls[af->nvls - 1];
1315
1316         tag = dwarf_tag(die_mem);
1317         if (tag == DW_TAG_formal_parameter ||
1318             tag == DW_TAG_variable) {
1319                 ret = convert_variable_location(die_mem, af->pf.addr,
1320                                                 af->pf.fb_ops, &af->pf.sp_die,
1321                                                 NULL);
1322                 if (ret == 0 || ret == -ERANGE) {
1323                         int ret2;
1324                         bool externs = !af->child;
1325
1326                         if (strbuf_init(&buf, 64) < 0)
1327                                 goto error;
1328
1329                         if (probe_conf.show_location_range) {
1330                                 if (!externs)
1331                                         ret2 = strbuf_add(&buf,
1332                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1333                                 else
1334                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1335                                 if (ret2)
1336                                         goto error;
1337                         }
1338
1339                         ret2 = die_get_varname(die_mem, &buf);
1340
1341                         if (!ret2 && probe_conf.show_location_range &&
1342                                 !externs) {
1343                                 if (strbuf_addch(&buf, '\t') < 0)
1344                                         goto error;
1345                                 ret2 = die_get_var_range(&af->pf.sp_die,
1346                                                         die_mem, &buf);
1347                         }
1348
1349                         pr_debug("Add new var: %s\n", buf.buf);
1350                         if (ret2 == 0) {
1351                                 strlist__add(vl->vars,
1352                                         strbuf_detach(&buf, NULL));
1353                         }
1354                         strbuf_release(&buf);
1355                 }
1356         }
1357
1358         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1359                 return DIE_FIND_CB_CONTINUE;
1360         else
1361                 return DIE_FIND_CB_SIBLING;
1362 error:
1363         strbuf_release(&buf);
1364         pr_debug("Error in strbuf\n");
1365         return DIE_FIND_CB_END;
1366 }
1367
1368 /* Add a found vars into available variables list */
1369 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1370 {
1371         struct available_var_finder *af =
1372                         container_of(pf, struct available_var_finder, pf);
1373         struct perf_probe_point *pp = &pf->pev->point;
1374         struct variable_list *vl;
1375         Dwarf_Die die_mem;
1376         int ret;
1377
1378         /* Check number of tevs */
1379         if (af->nvls == af->max_vls) {
1380                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1381                 return -ERANGE;
1382         }
1383         vl = &af->vls[af->nvls++];
1384
1385         /* Trace point should be converted from subprogram DIE */
1386         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1387                                      pp->retprobe, pp->function, &vl->point);
1388         if (ret < 0)
1389                 return ret;
1390
1391         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1392                  vl->point.offset);
1393
1394         /* Find local variables */
1395         vl->vars = strlist__new(NULL, NULL);
1396         if (vl->vars == NULL)
1397                 return -ENOMEM;
1398         af->child = true;
1399         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1400
1401         /* Find external variables */
1402         if (!probe_conf.show_ext_vars)
1403                 goto out;
1404         /* Don't need to search child DIE for external vars. */
1405         af->child = false;
1406         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1407
1408 out:
1409         if (strlist__empty(vl->vars)) {
1410                 strlist__delete(vl->vars);
1411                 vl->vars = NULL;
1412         }
1413
1414         return ret;
1415 }
1416
1417 /*
1418  * Find available variables at given probe point
1419  * Return the number of found probe points. Return 0 if there is no
1420  * matched probe point. Return <0 if an error occurs.
1421  */
1422 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1423                                       struct perf_probe_event *pev,
1424                                       struct variable_list **vls)
1425 {
1426         struct available_var_finder af = {
1427                         .pf = {.pev = pev, .callback = add_available_vars},
1428                         .mod = dbg->mod,
1429                         .max_vls = probe_conf.max_probes};
1430         int ret;
1431
1432         /* Allocate result vls array */
1433         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1434         if (*vls == NULL)
1435                 return -ENOMEM;
1436
1437         af.vls = *vls;
1438         af.nvls = 0;
1439
1440         ret = debuginfo__find_probes(dbg, &af.pf);
1441         if (ret < 0) {
1442                 /* Free vlist for error */
1443                 while (af.nvls--) {
1444                         zfree(&af.vls[af.nvls].point.symbol);
1445                         strlist__delete(af.vls[af.nvls].vars);
1446                 }
1447                 zfree(vls);
1448                 return ret;
1449         }
1450
1451         return (ret < 0) ? ret : af.nvls;
1452 }
1453
1454 /* For the kernel module, we need a special code to get a DIE */
1455 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1456 {
1457         int n, i;
1458         Elf32_Word shndx;
1459         Elf_Scn *scn;
1460         Elf *elf;
1461         GElf_Shdr mem, *shdr;
1462         const char *p;
1463
1464         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1465         if (!elf)
1466                 return -EINVAL;
1467
1468         /* Get the number of relocations */
1469         n = dwfl_module_relocations(dbg->mod);
1470         if (n < 0)
1471                 return -ENOENT;
1472         /* Search the relocation related .text section */
1473         for (i = 0; i < n; i++) {
1474                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1475                 if (strcmp(p, ".text") == 0) {
1476                         /* OK, get the section header */
1477                         scn = elf_getscn(elf, shndx);
1478                         if (!scn)
1479                                 return -ENOENT;
1480                         shdr = gelf_getshdr(scn, &mem);
1481                         if (!shdr)
1482                                 return -ENOENT;
1483                         *offs = shdr->sh_addr;
1484                 }
1485         }
1486         return 0;
1487 }
1488
1489 /* Reverse search */
1490 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1491                                 struct perf_probe_point *ppt)
1492 {
1493         Dwarf_Die cudie, spdie, indie;
1494         Dwarf_Addr _addr = 0, baseaddr = 0;
1495         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1496         int baseline = 0, lineno = 0, ret = 0;
1497         bool reloc = false;
1498
1499 retry:
1500         /* Find cu die */
1501         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1502                 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1503                         addr += baseaddr;
1504                         reloc = true;
1505                         goto retry;
1506                 }
1507                 pr_warning("Failed to find debug information for address %lx\n",
1508                            addr);
1509                 ret = -EINVAL;
1510                 goto end;
1511         }
1512
1513         /* Find a corresponding line (filename and lineno) */
1514         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1515         /* Don't care whether it failed or not */
1516
1517         /* Find a corresponding function (name, baseline and baseaddr) */
1518         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1519                 /* Get function entry information */
1520                 func = basefunc = dwarf_diename(&spdie);
1521                 if (!func ||
1522                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1523                     dwarf_decl_line(&spdie, &baseline) != 0) {
1524                         lineno = 0;
1525                         goto post;
1526                 }
1527
1528                 fname = dwarf_decl_file(&spdie);
1529                 if (addr == (unsigned long)baseaddr) {
1530                         /* Function entry - Relative line number is 0 */
1531                         lineno = baseline;
1532                         goto post;
1533                 }
1534
1535                 /* Track down the inline functions step by step */
1536                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1537                                                 &indie)) {
1538                         /* There is an inline function */
1539                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1540                             _addr == addr) {
1541                                 /*
1542                                  * addr is at an inline function entry.
1543                                  * In this case, lineno should be the call-site
1544                                  * line number. (overwrite lineinfo)
1545                                  */
1546                                 lineno = die_get_call_lineno(&indie);
1547                                 fname = die_get_call_file(&indie);
1548                                 break;
1549                         } else {
1550                                 /*
1551                                  * addr is in an inline function body.
1552                                  * Since lineno points one of the lines
1553                                  * of the inline function, baseline should
1554                                  * be the entry line of the inline function.
1555                                  */
1556                                 tmp = dwarf_diename(&indie);
1557                                 if (!tmp ||
1558                                     dwarf_decl_line(&indie, &baseline) != 0)
1559                                         break;
1560                                 func = tmp;
1561                                 spdie = indie;
1562                         }
1563                 }
1564                 /* Verify the lineno and baseline are in a same file */
1565                 tmp = dwarf_decl_file(&spdie);
1566                 if (!tmp || strcmp(tmp, fname) != 0)
1567                         lineno = 0;
1568         }
1569
1570 post:
1571         /* Make a relative line number or an offset */
1572         if (lineno)
1573                 ppt->line = lineno - baseline;
1574         else if (basefunc) {
1575                 ppt->offset = addr - (unsigned long)baseaddr;
1576                 func = basefunc;
1577         }
1578
1579         /* Duplicate strings */
1580         if (func) {
1581                 ppt->function = strdup(func);
1582                 if (ppt->function == NULL) {
1583                         ret = -ENOMEM;
1584                         goto end;
1585                 }
1586         }
1587         if (fname) {
1588                 ppt->file = strdup(fname);
1589                 if (ppt->file == NULL) {
1590                         zfree(&ppt->function);
1591                         ret = -ENOMEM;
1592                         goto end;
1593                 }
1594         }
1595 end:
1596         if (ret == 0 && (fname || func))
1597                 ret = 1;        /* Found a point */
1598         return ret;
1599 }
1600
1601 /* Add a line and store the src path */
1602 static int line_range_add_line(const char *src, unsigned int lineno,
1603                                struct line_range *lr)
1604 {
1605         /* Copy source path */
1606         if (!lr->path) {
1607                 lr->path = strdup(src);
1608                 if (lr->path == NULL)
1609                         return -ENOMEM;
1610         }
1611         return intlist__add(lr->line_list, lineno);
1612 }
1613
1614 static int line_range_walk_cb(const char *fname, int lineno,
1615                               Dwarf_Addr addr __maybe_unused,
1616                               void *data)
1617 {
1618         struct line_finder *lf = data;
1619         int err;
1620
1621         if ((strtailcmp(fname, lf->fname) != 0) ||
1622             (lf->lno_s > lineno || lf->lno_e < lineno))
1623                 return 0;
1624
1625         err = line_range_add_line(fname, lineno, lf->lr);
1626         if (err < 0 && err != -EEXIST)
1627                 return err;
1628
1629         return 0;
1630 }
1631
1632 /* Find line range from its line number */
1633 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1634 {
1635         int ret;
1636
1637         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1638
1639         /* Update status */
1640         if (ret >= 0)
1641                 if (!intlist__empty(lf->lr->line_list))
1642                         ret = lf->found = 1;
1643                 else
1644                         ret = 0;        /* Lines are not found */
1645         else {
1646                 zfree(&lf->lr->path);
1647         }
1648         return ret;
1649 }
1650
1651 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1652 {
1653         int ret = find_line_range_by_line(in_die, data);
1654
1655         /*
1656          * We have to check all instances of inlined function, because
1657          * some execution paths can be optimized out depends on the
1658          * function argument of instances. However, if an error occurs,
1659          * it should be handled by the caller.
1660          */
1661         return ret < 0 ? ret : 0;
1662 }
1663
1664 /* Search function definition from function name */
1665 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1666 {
1667         struct dwarf_callback_param *param = data;
1668         struct line_finder *lf = param->data;
1669         struct line_range *lr = lf->lr;
1670
1671         /* Check declared file */
1672         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1673                 return DWARF_CB_OK;
1674
1675         if (die_is_func_def(sp_die) &&
1676             die_match_name(sp_die, lr->function)) {
1677                 lf->fname = dwarf_decl_file(sp_die);
1678                 dwarf_decl_line(sp_die, &lr->offset);
1679                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1680                 lf->lno_s = lr->offset + lr->start;
1681                 if (lf->lno_s < 0)      /* Overflow */
1682                         lf->lno_s = INT_MAX;
1683                 lf->lno_e = lr->offset + lr->end;
1684                 if (lf->lno_e < 0)      /* Overflow */
1685                         lf->lno_e = INT_MAX;
1686                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1687                 lr->start = lf->lno_s;
1688                 lr->end = lf->lno_e;
1689                 if (!die_is_func_instance(sp_die))
1690                         param->retval = die_walk_instances(sp_die,
1691                                                 line_range_inline_cb, lf);
1692                 else
1693                         param->retval = find_line_range_by_line(sp_die, lf);
1694                 return DWARF_CB_ABORT;
1695         }
1696         return DWARF_CB_OK;
1697 }
1698
1699 static int find_line_range_by_func(struct line_finder *lf)
1700 {
1701         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1702         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1703         return param.retval;
1704 }
1705
1706 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1707 {
1708         struct line_finder lf = {.lr = lr, .found = 0};
1709         int ret = 0;
1710         Dwarf_Off off = 0, noff;
1711         size_t cuhl;
1712         Dwarf_Die *diep;
1713         const char *comp_dir;
1714
1715         /* Fastpath: lookup by function name from .debug_pubnames section */
1716         if (lr->function) {
1717                 struct pubname_callback_param pubname_param = {
1718                         .function = lr->function, .file = lr->file,
1719                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1720                 struct dwarf_callback_param line_range_param = {
1721                         .data = (void *)&lf, .retval = 0};
1722
1723                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1724                                   &pubname_param, 0);
1725                 if (pubname_param.found) {
1726                         line_range_search_cb(&lf.sp_die, &line_range_param);
1727                         if (lf.found)
1728                                 goto found;
1729                 }
1730         }
1731
1732         /* Loop on CUs (Compilation Unit) */
1733         while (!lf.found && ret >= 0) {
1734                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1735                                  NULL, NULL, NULL) != 0)
1736                         break;
1737
1738                 /* Get the DIE(Debugging Information Entry) of this CU */
1739                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1740                 if (!diep)
1741                         continue;
1742
1743                 /* Check if target file is included. */
1744                 if (lr->file)
1745                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1746                 else
1747                         lf.fname = 0;
1748
1749                 if (!lr->file || lf.fname) {
1750                         if (lr->function)
1751                                 ret = find_line_range_by_func(&lf);
1752                         else {
1753                                 lf.lno_s = lr->start;
1754                                 lf.lno_e = lr->end;
1755                                 ret = find_line_range_by_line(NULL, &lf);
1756                         }
1757                 }
1758                 off = noff;
1759         }
1760
1761 found:
1762         /* Store comp_dir */
1763         if (lf.found) {
1764                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1765                 if (comp_dir) {
1766                         lr->comp_dir = strdup(comp_dir);
1767                         if (!lr->comp_dir)
1768                                 ret = -ENOMEM;
1769                 }
1770         }
1771
1772         pr_debug("path: %s\n", lr->path);
1773         return (ret < 0) ? ret : lf.found;
1774 }
1775
1776 /*
1777  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1778  * and chop off leading directories that do not exist. Result is passed back as
1779  * a newly allocated path on success.
1780  * Return 0 if file was found and readable, -errno otherwise.
1781  */
1782 int get_real_path(const char *raw_path, const char *comp_dir,
1783                          char **new_path)
1784 {
1785         const char *prefix = symbol_conf.source_prefix;
1786
1787         if (!prefix) {
1788                 if (raw_path[0] != '/' && comp_dir)
1789                         /* If not an absolute path, try to use comp_dir */
1790                         prefix = comp_dir;
1791                 else {
1792                         if (access(raw_path, R_OK) == 0) {
1793                                 *new_path = strdup(raw_path);
1794                                 return *new_path ? 0 : -ENOMEM;
1795                         } else
1796                                 return -errno;
1797                 }
1798         }
1799
1800         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1801         if (!*new_path)
1802                 return -ENOMEM;
1803
1804         for (;;) {
1805                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1806
1807                 if (access(*new_path, R_OK) == 0)
1808                         return 0;
1809
1810                 if (!symbol_conf.source_prefix) {
1811                         /* In case of searching comp_dir, don't retry */
1812                         zfree(new_path);
1813                         return -errno;
1814                 }
1815
1816                 switch (errno) {
1817                 case ENAMETOOLONG:
1818                 case ENOENT:
1819                 case EROFS:
1820                 case EFAULT:
1821                         raw_path = strchr(++raw_path, '/');
1822                         if (!raw_path) {
1823                                 zfree(new_path);
1824                                 return -ENOENT;
1825                         }
1826                         continue;
1827
1828                 default:
1829                         zfree(new_path);
1830                         return -errno;
1831                 }
1832         }
1833 }