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 <inttypes.h>
  23 #include <sys/utsname.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <stdio.h>
  29 #include <unistd.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <stdarg.h>
  33 #include <dwarf-regs.h>
  34
  35 #include <linux/bitops.h>
  36 #include "event.h"
  37 #include "dso.h"
  38 #include "debug.h"
  39 #include "intlist.h"
  40 #include "util.h"
  41 #include "strlist.h"
  42 #include "symbol.h"
  43 #include "probe-finder.h"
  44 #include "probe-file.h"
  45 #include "string2.h"
  46
  47 /* Kprobe tracer basic type is up to u64 */
  48 #define MAX_BASIC_TYPE_BITS     64
  49
  50 /* Dwarf FL wrappers */
  51 static char *debuginfo_path;    /* Currently dummy */
  52
  53 static const Dwfl_Callbacks offline_callbacks = {
  54         .find_debuginfo = dwfl_standard_find_debuginfo,
  55         .debuginfo_path = &debuginfo_path,
  56
  57         .section_address = dwfl_offline_section_address,
  58
  59         /* We use this table for core files too.  */
  60         .find_elf = dwfl_build_id_find_elf,
  61 };
  62
  63 /* Get a Dwarf from offline image */
  64 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  65                                          const char *path)
  66 {
  67         int fd;
  68
  69         fd = open(path, O_RDONLY);
  70         if (fd < 0)
  71                 return fd;
  72
  73         dbg->dwfl = dwfl_begin(&offline_callbacks);
  74         if (!dbg->dwfl)
  75                 goto error;
  76
  77         dwfl_report_begin(dbg->dwfl);
  78         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  79         if (!dbg->mod)
  80                 goto error;
  81
  82         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  83         if (!dbg->dbg)
  84                 goto error;
  85
  86         dwfl_report_end(dbg->dwfl, NULL, NULL);
  87
  88         return 0;
  89 error:
  90         if (dbg->dwfl)
  91                 dwfl_end(dbg->dwfl);
  92         else
  93                 close(fd);
  94         memset(dbg, 0, sizeof(*dbg));
  95
  96         return -ENOENT;
  97 }
  98
  99 static struct debuginfo *__debuginfo__new(const char *path)
 100 {
 101         struct debuginfo *dbg = zalloc(sizeof(*dbg));
 102         if (!dbg)
 103                 return NULL;
 104
 105         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 106                 zfree(&dbg);
 107         if (dbg)
 108                 pr_debug("Open Debuginfo file: %s\n", path);
 109         return dbg;
 110 }
 111
 112 enum dso_binary_type distro_dwarf_types[] = {
 113         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 114         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 115         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 116         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 117         DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO,
 118         DSO_BINARY_TYPE__NOT_FOUND,
 119 };
 120
 121 struct debuginfo *debuginfo__new(const char *path)
 122 {
 123         enum dso_binary_type *type;
 124         char buf[PATH_MAX], nil = '\0';
 125         struct dso *dso;
 126         struct debuginfo *dinfo = NULL;
 127
 128         /* Try to open distro debuginfo files */
 129         dso = dso__new(path);
 130         if (!dso)
 131                 goto out;
 132
 133         for (type = distro_dwarf_types;
 134              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 135              type++) {
 136                 if (dso__read_binary_type_filename(dso, *type, &nil,
 137                                                    buf, PATH_MAX) < 0)
 138                         continue;
 139                 dinfo = __debuginfo__new(buf);
 140         }
 141         dso__put(dso);
 142
 143 out:
 144         /* if failed to open all distro debuginfo, open given binary */
 145         return dinfo ? : __debuginfo__new(path);
 146 }
 147
 148 void debuginfo__delete(struct debuginfo *dbg)
 149 {
 150         if (dbg) {
 151                 if (dbg->dwfl)
 152                         dwfl_end(dbg->dwfl);
 153                 free(dbg);
 154         }
 155 }
 156
 157 /*
 158  * Probe finder related functions
 159  */
 160
 161 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 162 {
 163         struct probe_trace_arg_ref *ref;
 164         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 165         if (ref != NULL)
 166                 ref->offset = offs;
 167         return ref;
 168 }
 169
 170 /*
 171  * Convert a location into trace_arg.
 172  * If tvar == NULL, this just checks variable can be converted.
 173  * If fentry == true and vr_die is a parameter, do huristic search
 174  * for the location fuzzed by function entry mcount.
 175  */
 176 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 177                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 178                                      unsigned int machine,
 179                                      struct probe_trace_arg *tvar)
 180 {
 181         Dwarf_Attribute attr;
 182         Dwarf_Addr tmp = 0;
 183         Dwarf_Op *op;
 184         size_t nops;
 185         unsigned int regn;
 186         Dwarf_Word offs = 0;
 187         bool ref = false;
 188         const char *regs;
 189         int ret, ret2 = 0;
 190
 191         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 192                 goto static_var;
 193
 194         /* TODO: handle more than 1 exprs */
 195         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 196                 return -EINVAL; /* Broken DIE ? */
 197         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 198                 ret = dwarf_entrypc(sp_die, &tmp);
 199                 if (ret)
 200                         return -ENOENT;
 201
 202                 if (probe_conf.show_location_range &&
 203                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 204                         ret2 = -ERANGE;
 205                 } else if (addr != tmp ||
 206                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 207                         return -ENOENT;
 208                 }
 209
 210                 ret = dwarf_highpc(sp_die, &tmp);
 211                 if (ret)
 212                         return -ENOENT;
 213                 /*
 214                  * This is fuzzed by fentry mcount. We try to find the
 215                  * parameter location at the earliest address.
 216                  */
 217                 for (addr += 1; addr <= tmp; addr++) {
 218                         if (dwarf_getlocation_addr(&attr, addr, &op,
 219                                                    &nops, 1) > 0)
 220                                 goto found;
 221                 }
 222                 return -ENOENT;
 223         }
 224 found:
 225         if (nops == 0)
 226                 /* TODO: Support const_value */
 227                 return -ENOENT;
 228
 229         if (op->atom == DW_OP_addr) {
 230 static_var:
 231                 if (!tvar)
 232                         return ret2;
 233                 /* Static variables on memory (not stack), make @varname */
 234                 ret = strlen(dwarf_diename(vr_die));
 235                 tvar->value = zalloc(ret + 2);
 236                 if (tvar->value == NULL)
 237                         return -ENOMEM;
 238                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 239                 tvar->ref = alloc_trace_arg_ref((long)offs);
 240                 if (tvar->ref == NULL)
 241                         return -ENOMEM;
 242                 return ret2;
 243         }
 244
 245         /* If this is based on frame buffer, set the offset */
 246         if (op->atom == DW_OP_fbreg) {
 247                 if (fb_ops == NULL)
 248                         return -ENOTSUP;
 249                 ref = true;
 250                 offs = op->number;
 251                 op = &fb_ops[0];
 252         }
 253
 254         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 255                 regn = op->atom - DW_OP_breg0;
 256                 offs += op->number;
 257                 ref = true;
 258         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 259                 regn = op->atom - DW_OP_reg0;
 260         } else if (op->atom == DW_OP_bregx) {
 261                 regn = op->number;
 262                 offs += op->number2;
 263                 ref = true;
 264         } else if (op->atom == DW_OP_regx) {
 265                 regn = op->number;
 266         } else {
 267                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 268                 return -ENOTSUP;
 269         }
 270
 271         if (!tvar)
 272                 return ret2;
 273
 274         regs = get_dwarf_regstr(regn, machine);
 275         if (!regs) {
 276                 /* This should be a bug in DWARF or this tool */
 277                 pr_warning("Mapping for the register number %u "
 278                            "missing on this architecture.\n", regn);
 279                 return -ENOTSUP;
 280         }
 281
 282         tvar->value = strdup(regs);
 283         if (tvar->value == NULL)
 284                 return -ENOMEM;
 285
 286         if (ref) {
 287                 tvar->ref = alloc_trace_arg_ref((long)offs);
 288                 if (tvar->ref == NULL)
 289                         return -ENOMEM;
 290         }
 291         return ret2;
 292 }
 293
 294 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 295
 296 static int convert_variable_type(Dwarf_Die *vr_die,
 297                                  struct probe_trace_arg *tvar,
 298                                  const char *cast)
 299 {
 300         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 301         Dwarf_Die type;
 302         char buf[16];
 303         char sbuf[STRERR_BUFSIZE];
 304         int bsize, boffs, total;
 305         int ret;
 306         char prefix;
 307
 308         /* TODO: check all types */
 309         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 310             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 311                 /* Non string type is OK */
 312                 /* and respect signedness/hexadecimal cast */
 313                 tvar->type = strdup(cast);
 314                 return (tvar->type == NULL) ? -ENOMEM : 0;
 315         }
 316
 317         bsize = dwarf_bitsize(vr_die);
 318         if (bsize > 0) {
 319                 /* This is a bitfield */
 320                 boffs = dwarf_bitoffset(vr_die);
 321                 total = dwarf_bytesize(vr_die);
 322                 if (boffs < 0 || total < 0)
 323                         return -ENOENT;
 324                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 325                                 BYTES_TO_BITS(total));
 326                 goto formatted;
 327         }
 328
 329         if (die_get_real_type(vr_die, &type) == NULL) {
 330                 pr_warning("Failed to get a type information of %s.\n",
 331                            dwarf_diename(vr_die));
 332                 return -ENOENT;
 333         }
 334
 335         pr_debug("%s type is %s.\n",
 336                  dwarf_diename(vr_die), dwarf_diename(&type));
 337
 338         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 339                 ret = dwarf_tag(&type);
 340                 if (ret != DW_TAG_pointer_type &&
 341                     ret != DW_TAG_array_type) {
 342                         pr_warning("Failed to cast into string: "
 343                                    "%s(%s) is not a pointer nor array.\n",
 344                                    dwarf_diename(vr_die), dwarf_diename(&type));
 345                         return -EINVAL;
 346                 }
 347                 if (die_get_real_type(&type, &type) == NULL) {
 348                         pr_warning("Failed to get a type"
 349                                    " information.\n");
 350                         return -ENOENT;
 351                 }
 352                 if (ret == DW_TAG_pointer_type) {
 353                         while (*ref_ptr)
 354                                 ref_ptr = &(*ref_ptr)->next;
 355                         /* Add new reference with offset +0 */
 356                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 357                         if (*ref_ptr == NULL) {
 358                                 pr_warning("Out of memory error\n");
 359                                 return -ENOMEM;
 360                         }
 361                 }
 362                 if (!die_compare_name(&type, "char") &&
 363                     !die_compare_name(&type, "unsigned char")) {
 364                         pr_warning("Failed to cast into string: "
 365                                    "%s is not (unsigned) char *.\n",
 366                                    dwarf_diename(vr_die));
 367                         return -EINVAL;
 368                 }
 369                 tvar->type = strdup(cast);
 370                 return (tvar->type == NULL) ? -ENOMEM : 0;
 371         }
 372
 373         if (cast && (strcmp(cast, "u") == 0))
 374                 prefix = 'u';
 375         else if (cast && (strcmp(cast, "s") == 0))
 376                 prefix = 's';
 377         else if (cast && (strcmp(cast, "x") == 0) &&
 378                  probe_type_is_available(PROBE_TYPE_X))
 379                 prefix = 'x';
 380         else
 381                 prefix = die_is_signed_type(&type) ? 's' :
 382                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 383
 384         ret = dwarf_bytesize(&type);
 385         if (ret <= 0)
 386                 /* No size ... try to use default type */
 387                 return 0;
 388         ret = BYTES_TO_BITS(ret);
 389
 390         /* Check the bitwidth */
 391         if (ret > MAX_BASIC_TYPE_BITS) {
 392                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 393                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 394                 ret = MAX_BASIC_TYPE_BITS;
 395         }
 396         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 397
 398 formatted:
 399         if (ret < 0 || ret >= 16) {
 400                 if (ret >= 16)
 401                         ret = -E2BIG;
 402                 pr_warning("Failed to convert variable type: %s\n",
 403                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 404                 return ret;
 405         }
 406         tvar->type = strdup(buf);
 407         if (tvar->type == NULL)
 408                 return -ENOMEM;
 409         return 0;
 410 }
 411
 412 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 413                                     struct perf_probe_arg_field *field,
 414                                     struct probe_trace_arg_ref **ref_ptr,
 415                                     Dwarf_Die *die_mem)
 416 {
 417         struct probe_trace_arg_ref *ref = *ref_ptr;
 418         Dwarf_Die type;
 419         Dwarf_Word offs;
 420         int ret, tag;
 421
 422         pr_debug("converting %s in %s\n", field->name, varname);
 423         if (die_get_real_type(vr_die, &type) == NULL) {
 424                 pr_warning("Failed to get the type of %s.\n", varname);
 425                 return -ENOENT;
 426         }
 427         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 428         tag = dwarf_tag(&type);
 429
 430         if (field->name[0] == '[' &&
 431             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 432                 if (field->next)
 433                         /* Save original type for next field */
 434                         memcpy(die_mem, &type, sizeof(*die_mem));
 435                 /* Get the type of this array */
 436                 if (die_get_real_type(&type, &type) == NULL) {
 437                         pr_warning("Failed to get the type of %s.\n", varname);
 438                         return -ENOENT;
 439                 }
 440                 pr_debug2("Array real type: (%x)\n",
 441                          (unsigned)dwarf_dieoffset(&type));
 442                 if (tag == DW_TAG_pointer_type) {
 443                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 444                         if (ref == NULL)
 445                                 return -ENOMEM;
 446                         if (*ref_ptr)
 447                                 (*ref_ptr)->next = ref;
 448                         else
 449                                 *ref_ptr = ref;
 450                 }
 451                 ref->offset += dwarf_bytesize(&type) * field->index;
 452                 if (!field->next)
 453                         /* Save vr_die for converting types */
 454                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 455                 goto next;
 456         } else if (tag == DW_TAG_pointer_type) {
 457                 /* Check the pointer and dereference */
 458                 if (!field->ref) {
 459                         pr_err("Semantic error: %s must be referred by '->'\n",
 460                                field->name);
 461                         return -EINVAL;
 462                 }
 463                 /* Get the type pointed by this pointer */
 464                 if (die_get_real_type(&type, &type) == NULL) {
 465                         pr_warning("Failed to get the type of %s.\n", varname);
 466                         return -ENOENT;
 467                 }
 468                 /* Verify it is a data structure  */
 469                 tag = dwarf_tag(&type);
 470                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 471                         pr_warning("%s is not a data structure nor a union.\n",
 472                                    varname);
 473                         return -EINVAL;
 474                 }
 475
 476                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 477                 if (ref == NULL)
 478                         return -ENOMEM;
 479                 if (*ref_ptr)
 480                         (*ref_ptr)->next = ref;
 481                 else
 482                         *ref_ptr = ref;
 483         } else {
 484                 /* Verify it is a data structure  */
 485                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 486                         pr_warning("%s is not a data structure nor a union.\n",
 487                                    varname);
 488                         return -EINVAL;
 489                 }
 490                 if (field->name[0] == '[') {
 491                         pr_err("Semantic error: %s is not a pointer"
 492                                " nor array.\n", varname);
 493                         return -EINVAL;
 494                 }
 495                 /* While prcessing unnamed field, we don't care about this */
 496                 if (field->ref && dwarf_diename(vr_die)) {
 497                         pr_err("Semantic error: %s must be referred by '.'\n",
 498                                field->name);
 499                         return -EINVAL;
 500                 }
 501                 if (!ref) {
 502                         pr_warning("Structure on a register is not "
 503                                    "supported yet.\n");
 504                         return -ENOTSUP;
 505                 }
 506         }
 507
 508         if (die_find_member(&type, field->name, die_mem) == NULL) {
 509                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 510                            dwarf_diename(&type), field->name);
 511                 return -EINVAL;
 512         }
 513
 514         /* Get the offset of the field */
 515         if (tag == DW_TAG_union_type) {
 516                 offs = 0;
 517         } else {
 518                 ret = die_get_data_member_location(die_mem, &offs);
 519                 if (ret < 0) {
 520                         pr_warning("Failed to get the offset of %s.\n",
 521                                    field->name);
 522                         return ret;
 523                 }
 524         }
 525         ref->offset += (long)offs;
 526
 527         /* If this member is unnamed, we need to reuse this field */
 528         if (!dwarf_diename(die_mem))
 529                 return convert_variable_fields(die_mem, varname, field,
 530                                                 &ref, die_mem);
 531
 532 next:
 533         /* Converting next field */
 534         if (field->next)
 535                 return convert_variable_fields(die_mem, field->name,
 536                                         field->next, &ref, die_mem);
 537         else
 538                 return 0;
 539 }
 540
 541 /* Show a variables in kprobe event format */
 542 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 543 {
 544         Dwarf_Die die_mem;
 545         int ret;
 546
 547         pr_debug("Converting variable %s into trace event.\n",
 548                  dwarf_diename(vr_die));
 549
 550         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 551                                         &pf->sp_die, pf->machine, pf->tvar);
 552         if (ret == -ENOENT || ret == -EINVAL) {
 553                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 554                        " Perhaps it has been optimized out.\n"
 555                        " Use -V with the --range option to show '%s' location range.\n",
 556                        pf->pvar->var, pf->pvar->var);
 557         } else if (ret == -ENOTSUP)
 558                 pr_err("Sorry, we don't support this variable location yet.\n");
 559         else if (ret == 0 && pf->pvar->field) {
 560                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 561                                               pf->pvar->field, &pf->tvar->ref,
 562                                               &die_mem);
 563                 vr_die = &die_mem;
 564         }
 565         if (ret == 0)
 566                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 567         /* *expr will be cached in libdw. Don't free it. */
 568         return ret;
 569 }
 570
 571 /* Find a variable in a scope DIE */
 572 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 573 {
 574         Dwarf_Die vr_die;
 575         char *buf, *ptr;
 576         int ret = 0;
 577
 578         /* Copy raw parameters */
 579         if (!is_c_varname(pf->pvar->var))
 580                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 581
 582         if (pf->pvar->name)
 583                 pf->tvar->name = strdup(pf->pvar->name);
 584         else {
 585                 buf = synthesize_perf_probe_arg(pf->pvar);
 586                 if (!buf)
 587                         return -ENOMEM;
 588                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 589                 if (ptr)
 590                         *ptr = '_';
 591                 pf->tvar->name = buf;
 592         }
 593         if (pf->tvar->name == NULL)
 594                 return -ENOMEM;
 595
 596         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 597         /* Search child die for local variables and parameters. */
 598         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 599                 /* Search again in global variables */
 600                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 601                                                 0, &vr_die)) {
 602                         pr_warning("Failed to find '%s' in this function.\n",
 603                                    pf->pvar->var);
 604                         ret = -ENOENT;
 605                 }
 606         }
 607         if (ret >= 0)
 608                 ret = convert_variable(&vr_die, pf);
 609
 610         return ret;
 611 }
 612
 613 /* Convert subprogram DIE to trace point */
 614 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 615                                   Dwarf_Addr paddr, bool retprobe,
 616                                   const char *function,
 617                                   struct probe_trace_point *tp)
 618 {
 619         Dwarf_Addr eaddr;
 620         GElf_Sym sym;
 621         const char *symbol;
 622
 623         /* Verify the address is correct */
 624         if (!dwarf_haspc(sp_die, paddr)) {
 625                 pr_warning("Specified offset is out of %s\n",
 626                            dwarf_diename(sp_die));
 627                 return -EINVAL;
 628         }
 629
 630         if (dwarf_entrypc(sp_die, &eaddr) == 0) {
 631                 /* If the DIE has entrypc, use it. */
 632                 symbol = dwarf_diename(sp_die);
 633         } else {
 634                 /* Try to get actual symbol name and address from symtab */
 635                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 636                 eaddr = sym.st_value;
 637         }
 638         if (!symbol) {
 639                 pr_warning("Failed to find symbol at 0x%lx\n",
 640                            (unsigned long)paddr);
 641                 return -ENOENT;
 642         }
 643
 644         tp->offset = (unsigned long)(paddr - eaddr);
 645         tp->address = (unsigned long)paddr;
 646         tp->symbol = strdup(symbol);
 647         if (!tp->symbol)
 648                 return -ENOMEM;
 649
 650         /* Return probe must be on the head of a subprogram */
 651         if (retprobe) {
 652                 if (eaddr != paddr) {
 653                         pr_warning("Failed to find \"%s%%return\",\n"
 654                                    " because %s is an inlined function and"
 655                                    " has no return point.\n", function,
 656                                    function);
 657                         return -EINVAL;
 658                 }
 659                 tp->retprobe = true;
 660         }
 661
 662         return 0;
 663 }
 664
 665 /* Call probe_finder callback with scope DIE */
 666 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 667 {
 668         Dwarf_Attribute fb_attr;
 669         Dwarf_Frame *frame = NULL;
 670         size_t nops;
 671         int ret;
 672
 673         if (!sc_die) {
 674                 pr_err("Caller must pass a scope DIE. Program error.\n");
 675                 return -EINVAL;
 676         }
 677
 678         /* If not a real subprogram, find a real one */
 679         if (!die_is_func_def(sc_die)) {
 680                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 681                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 682                                 pr_warning("Ignoring tail call from %s\n",
 683                                                 dwarf_diename(&pf->sp_die));
 684                                 return 0;
 685                         } else {
 686                                 pr_warning("Failed to find probe point in any "
 687                                            "functions.\n");
 688                                 return -ENOENT;
 689                         }
 690                 }
 691         } else
 692                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 693
 694         /* Get the frame base attribute/ops from subprogram */
 695         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 696         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 697         if (ret <= 0 || nops == 0) {
 698                 pf->fb_ops = NULL;
 699 #if _ELFUTILS_PREREQ(0, 142)
 700         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 701                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 702                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 703                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 704                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 705                         pr_warning("Failed to get call frame on 0x%jx\n",
 706                                    (uintmax_t)pf->addr);
 707                         free(frame);
 708                         return -ENOENT;
 709                 }
 710 #endif
 711         }
 712
 713         /* Call finder's callback handler */
 714         ret = pf->callback(sc_die, pf);
 715
 716         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 717         free(frame);
 718         pf->fb_ops = NULL;
 719
 720         return ret;
 721 }
 722
 723 struct find_scope_param {
 724         const char *function;
 725         const char *file;
 726         int line;
 727         int diff;
 728         Dwarf_Die *die_mem;
 729         bool found;
 730 };
 731
 732 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 733 {
 734         struct find_scope_param *fsp = data;
 735         const char *file;
 736         int lno;
 737
 738         /* Skip if declared file name does not match */
 739         if (fsp->file) {
 740                 file = dwarf_decl_file(fn_die);
 741                 if (!file || strcmp(fsp->file, file) != 0)
 742                         return 0;
 743         }
 744         /* If the function name is given, that's what user expects */
 745         if (fsp->function) {
 746                 if (die_match_name(fn_die, fsp->function)) {
 747                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 748                         fsp->found = true;
 749                         return 1;
 750                 }
 751         } else {
 752                 /* With the line number, find the nearest declared DIE */
 753                 dwarf_decl_line(fn_die, &lno);
 754                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 755                         /* Keep a candidate and continue */
 756                         fsp->diff = fsp->line - lno;
 757                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 758                         fsp->found = true;
 759                 }
 760         }
 761         return 0;
 762 }
 763
 764 /* Return innermost DIE */
 765 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
 766 {
 767         struct find_scope_param *fsp = data;
 768
 769         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 770         fsp->found = true;
 771         return 1;
 772 }
 773
 774 /* Find an appropriate scope fits to given conditions */
 775 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 776 {
 777         struct find_scope_param fsp = {
 778                 .function = pf->pev->point.function,
 779                 .file = pf->fname,
 780                 .line = pf->lno,
 781                 .diff = INT_MAX,
 782                 .die_mem = die_mem,
 783                 .found = false,
 784         };
 785         int ret;
 786
 787         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
 788                                    &fsp);
 789         if (!ret && !fsp.found)
 790                 cu_walk_functions_at(&pf->cu_die, pf->addr,
 791                                      find_inner_scope_cb, &fsp);
 792
 793         return fsp.found ? die_mem : NULL;
 794 }
 795
 796 static int probe_point_line_walker(const char *fname, int lineno,
 797                                    Dwarf_Addr addr, void *data)
 798 {
 799         struct probe_finder *pf = data;
 800         Dwarf_Die *sc_die, die_mem;
 801         int ret;
 802
 803         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 804                 return 0;
 805
 806         pf->addr = addr;
 807         sc_die = find_best_scope(pf, &die_mem);
 808         if (!sc_die) {
 809                 pr_warning("Failed to find scope of probe point.\n");
 810                 return -ENOENT;
 811         }
 812
 813         ret = call_probe_finder(sc_die, pf);
 814
 815         /* Continue if no error, because the line will be in inline function */
 816         return ret < 0 ? ret : 0;
 817 }
 818
 819 /* Find probe point from its line number */
 820 static int find_probe_point_by_line(struct probe_finder *pf)
 821 {
 822         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 823 }
 824
 825 /* Find lines which match lazy pattern */
 826 static int find_lazy_match_lines(struct intlist *list,
 827                                  const char *fname, const char *pat)
 828 {
 829         FILE *fp;
 830         char *line = NULL;
 831         size_t line_len;
 832         ssize_t len;
 833         int count = 0, linenum = 1;
 834         char sbuf[STRERR_BUFSIZE];
 835
 836         fp = fopen(fname, "r");
 837         if (!fp) {
 838                 pr_warning("Failed to open %s: %s\n", fname,
 839                            str_error_r(errno, sbuf, sizeof(sbuf)));
 840                 return -errno;
 841         }
 842
 843         while ((len = getline(&line, &line_len, fp)) > 0) {
 844
 845                 if (line[len - 1] == '\n')
 846                         line[len - 1] = '\0';
 847
 848                 if (strlazymatch(line, pat)) {
 849                         intlist__add(list, linenum);
 850                         count++;
 851                 }
 852                 linenum++;
 853         }
 854
 855         if (ferror(fp))
 856                 count = -errno;
 857         free(line);
 858         fclose(fp);
 859
 860         if (count == 0)
 861                 pr_debug("No matched lines found in %s.\n", fname);
 862         return count;
 863 }
 864
 865 static int probe_point_lazy_walker(const char *fname, int lineno,
 866                                    Dwarf_Addr addr, void *data)
 867 {
 868         struct probe_finder *pf = data;
 869         Dwarf_Die *sc_die, die_mem;
 870         int ret;
 871
 872         if (!intlist__has_entry(pf->lcache, lineno) ||
 873             strtailcmp(fname, pf->fname) != 0)
 874                 return 0;
 875
 876         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 877                  lineno, (unsigned long long)addr);
 878         pf->addr = addr;
 879         pf->lno = lineno;
 880         sc_die = find_best_scope(pf, &die_mem);
 881         if (!sc_die) {
 882                 pr_warning("Failed to find scope of probe point.\n");
 883                 return -ENOENT;
 884         }
 885
 886         ret = call_probe_finder(sc_die, pf);
 887
 888         /*
 889          * Continue if no error, because the lazy pattern will match
 890          * to other lines
 891          */
 892         return ret < 0 ? ret : 0;
 893 }
 894
 895 /* Find probe points from lazy pattern  */
 896 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 897 {
 898         int ret = 0;
 899         char *fpath;
 900
 901         if (intlist__empty(pf->lcache)) {
 902                 const char *comp_dir;
 903
 904                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 905                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 906                 if (ret < 0) {
 907                         pr_warning("Failed to find source file path.\n");
 908                         return ret;
 909                 }
 910
 911                 /* Matching lazy line pattern */
 912                 ret = find_lazy_match_lines(pf->lcache, fpath,
 913                                             pf->pev->point.lazy_line);
 914                 free(fpath);
 915                 if (ret <= 0)
 916                         return ret;
 917         }
 918
 919         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 920 }
 921
 922 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 923 {
 924         struct perf_probe_point *pp = &pf->pev->point;
 925
 926         /* Not uprobe? */
 927         if (!pf->pev->uprobes)
 928                 return;
 929
 930         /* Compiled with optimization? */
 931         if (die_is_optimized_target(&pf->cu_die))
 932                 return;
 933
 934         /* Don't know entrypc? */
 935         if (!pf->addr)
 936                 return;
 937
 938         /* Only FUNC and FUNC@SRC are eligible. */
 939         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 940             pp->offset || pp->abs_address)
 941                 return;
 942
 943         /* Not interested in func parameter? */
 944         if (!perf_probe_with_var(pf->pev))
 945                 return;
 946
 947         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 948                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 949                 pf->addr);
 950
 951         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 952 }
 953
 954 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 955 {
 956         struct probe_finder *pf = data;
 957         struct perf_probe_point *pp = &pf->pev->point;
 958         Dwarf_Addr addr;
 959         int ret;
 960
 961         if (pp->lazy_line)
 962                 ret = find_probe_point_lazy(in_die, pf);
 963         else {
 964                 /* Get probe address */
 965                 if (die_entrypc(in_die, &addr) != 0) {
 966                         pr_warning("Failed to get entry address of %s.\n",
 967                                    dwarf_diename(in_die));
 968                         return -ENOENT;
 969                 }
 970                 if (addr == 0) {
 971                         pr_debug("%s has no valid entry address. skipped.\n",
 972                                  dwarf_diename(in_die));
 973                         return -ENOENT;
 974                 }
 975                 pf->addr = addr;
 976                 pf->addr += pp->offset;
 977                 pr_debug("found inline addr: 0x%jx\n",
 978                          (uintmax_t)pf->addr);
 979
 980                 ret = call_probe_finder(in_die, pf);
 981         }
 982
 983         return ret;
 984 }
 985
 986 /* Callback parameter with return value for libdw */
 987 struct dwarf_callback_param {
 988         void *data;
 989         int retval;
 990 };
 991
 992 /* Search function from function name */
 993 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 994 {
 995         struct dwarf_callback_param *param = data;
 996         struct probe_finder *pf = param->data;
 997         struct perf_probe_point *pp = &pf->pev->point;
 998
 999         /* Check tag and diename */
1000         if (!die_is_func_def(sp_die) ||
1001             !die_match_name(sp_die, pp->function))
1002                 return DWARF_CB_OK;
1003
1004         /* Check declared file */
1005         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1006                 return DWARF_CB_OK;
1007
1008         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1009                  (unsigned long)dwarf_dieoffset(sp_die));
1010         pf->fname = dwarf_decl_file(sp_die);
1011         if (pp->line) { /* Function relative line */
1012                 dwarf_decl_line(sp_die, &pf->lno);
1013                 pf->lno += pp->line;
1014                 param->retval = find_probe_point_by_line(pf);
1015         } else if (die_is_func_instance(sp_die)) {
1016                 /* Instances always have the entry address */
1017                 die_entrypc(sp_die, &pf->addr);
1018                 /* But in some case the entry address is 0 */
1019                 if (pf->addr == 0) {
1020                         pr_debug("%s has no entry PC. Skipped\n",
1021                                  dwarf_diename(sp_die));
1022                         param->retval = 0;
1023                 /* Real function */
1024                 } else if (pp->lazy_line)
1025                         param->retval = find_probe_point_lazy(sp_die, pf);
1026                 else {
1027                         skip_prologue(sp_die, pf);
1028                         pf->addr += pp->offset;
1029                         /* TODO: Check the address in this function */
1030                         param->retval = call_probe_finder(sp_die, pf);
1031                 }
1032         } else if (!probe_conf.no_inlines) {
1033                 /* Inlined function: search instances */
1034                 param->retval = die_walk_instances(sp_die,
1035                                         probe_point_inline_cb, (void *)pf);
1036                 /* This could be a non-existed inline definition */
1037                 if (param->retval == -ENOENT)
1038                         param->retval = 0;
1039         }
1040
1041         /* We need to find other candidates */
1042         if (strisglob(pp->function) && param->retval >= 0) {
1043                 param->retval = 0;      /* We have to clear the result */
1044                 return DWARF_CB_OK;
1045         }
1046
1047         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1048 }
1049
1050 static int find_probe_point_by_func(struct probe_finder *pf)
1051 {
1052         struct dwarf_callback_param _param = {.data = (void *)pf,
1053                                               .retval = 0};
1054         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1055         return _param.retval;
1056 }
1057
1058 struct pubname_callback_param {
1059         char *function;
1060         char *file;
1061         Dwarf_Die *cu_die;
1062         Dwarf_Die *sp_die;
1063         int found;
1064 };
1065
1066 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1067 {
1068         struct pubname_callback_param *param = data;
1069
1070         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1071                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1072                         return DWARF_CB_OK;
1073
1074                 if (die_match_name(param->sp_die, param->function)) {
1075                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1076                                 return DWARF_CB_OK;
1077
1078                         if (param->file &&
1079                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1080                                 return DWARF_CB_OK;
1081
1082                         param->found = 1;
1083                         return DWARF_CB_ABORT;
1084                 }
1085         }
1086
1087         return DWARF_CB_OK;
1088 }
1089
1090 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1091                                   struct probe_finder *pf)
1092 {
1093         struct perf_probe_point *pp = &pf->pev->point;
1094         Dwarf_Off off, noff;
1095         size_t cuhl;
1096         Dwarf_Die *diep;
1097         int ret = 0;
1098
1099         off = 0;
1100         pf->lcache = intlist__new(NULL);
1101         if (!pf->lcache)
1102                 return -ENOMEM;
1103
1104         /* Fastpath: lookup by function name from .debug_pubnames section */
1105         if (pp->function && !strisglob(pp->function)) {
1106                 struct pubname_callback_param pubname_param = {
1107                         .function = pp->function,
1108                         .file     = pp->file,
1109                         .cu_die   = &pf->cu_die,
1110                         .sp_die   = &pf->sp_die,
1111                         .found    = 0,
1112                 };
1113                 struct dwarf_callback_param probe_param = {
1114                         .data = pf,
1115                 };
1116
1117                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1118                                   &pubname_param, 0);
1119                 if (pubname_param.found) {
1120                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1121                         if (ret)
1122                                 goto found;
1123                 }
1124         }
1125
1126         /* Loop on CUs (Compilation Unit) */
1127         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1128                 /* Get the DIE(Debugging Information Entry) of this CU */
1129                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1130                 if (!diep)
1131                         continue;
1132
1133                 /* Check if target file is included. */
1134                 if (pp->file)
1135                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1136                 else
1137                         pf->fname = NULL;
1138
1139                 if (!pp->file || pf->fname) {
1140                         if (pp->function)
1141                                 ret = find_probe_point_by_func(pf);
1142                         else if (pp->lazy_line)
1143                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1144                         else {
1145                                 pf->lno = pp->line;
1146                                 ret = find_probe_point_by_line(pf);
1147                         }
1148                         if (ret < 0)
1149                                 break;
1150                 }
1151                 off = noff;
1152         }
1153
1154 found:
1155         intlist__delete(pf->lcache);
1156         pf->lcache = NULL;
1157
1158         return ret;
1159 }
1160
1161 /* Find probe points from debuginfo */
1162 static int debuginfo__find_probes(struct debuginfo *dbg,
1163                                   struct probe_finder *pf)
1164 {
1165         int ret = 0;
1166         Elf *elf;
1167         GElf_Ehdr ehdr;
1168
1169         if (pf->cfi_eh || pf->cfi_dbg)
1170                 return debuginfo__find_probe_location(dbg, pf);
1171
1172         /* Get the call frame information from this dwarf */
1173         elf = dwarf_getelf(dbg->dbg);
1174         if (elf == NULL)
1175                 return -EINVAL;
1176
1177         if (gelf_getehdr(elf, &ehdr) == NULL)
1178                 return -EINVAL;
1179
1180         pf->machine = ehdr.e_machine;
1181
1182 #if _ELFUTILS_PREREQ(0, 142)
1183         do {
1184                 GElf_Shdr shdr;
1185
1186                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1187                     shdr.sh_type == SHT_PROGBITS)
1188                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1189
1190                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1191         } while (0);
1192 #endif
1193
1194         ret = debuginfo__find_probe_location(dbg, pf);
1195         return ret;
1196 }
1197
1198 struct local_vars_finder {
1199         struct probe_finder *pf;
1200         struct perf_probe_arg *args;
1201         bool vars;
1202         int max_args;
1203         int nargs;
1204         int ret;
1205 };
1206
1207 /* Collect available variables in this scope */
1208 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1209 {
1210         struct local_vars_finder *vf = data;
1211         struct probe_finder *pf = vf->pf;
1212         int tag;
1213
1214         tag = dwarf_tag(die_mem);
1215         if (tag == DW_TAG_formal_parameter ||
1216             (tag == DW_TAG_variable && vf->vars)) {
1217                 if (convert_variable_location(die_mem, vf->pf->addr,
1218                                               vf->pf->fb_ops, &pf->sp_die,
1219                                               pf->machine, NULL) == 0) {
1220                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1221                         if (vf->args[vf->nargs].var == NULL) {
1222                                 vf->ret = -ENOMEM;
1223                                 return DIE_FIND_CB_END;
1224                         }
1225                         pr_debug(" %s", vf->args[vf->nargs].var);
1226                         vf->nargs++;
1227                 }
1228         }
1229
1230         if (dwarf_haspc(die_mem, vf->pf->addr))
1231                 return DIE_FIND_CB_CONTINUE;
1232         else
1233                 return DIE_FIND_CB_SIBLING;
1234 }
1235
1236 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1237                              struct perf_probe_arg *args)
1238 {
1239         Dwarf_Die die_mem;
1240         int i;
1241         int n = 0;
1242         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1243                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1244
1245         for (i = 0; i < pf->pev->nargs; i++) {
1246                 /* var never be NULL */
1247                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1248                         vf.vars = true;
1249                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1250                         /* Copy normal argument */
1251                         args[n] = pf->pev->args[i];
1252                         n++;
1253                         continue;
1254                 }
1255                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1256                 vf.nargs = n;
1257                 /* Special local variables */
1258                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1259                                &die_mem);
1260                 pr_debug(" (%d)\n", vf.nargs - n);
1261                 if (vf.ret < 0)
1262                         return vf.ret;
1263                 n = vf.nargs;
1264         }
1265         return n;
1266 }
1267
1268 /* Add a found probe point into trace event list */
1269 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1270 {
1271         struct trace_event_finder *tf =
1272                         container_of(pf, struct trace_event_finder, pf);
1273         struct perf_probe_point *pp = &pf->pev->point;
1274         struct probe_trace_event *tev;
1275         struct perf_probe_arg *args = NULL;
1276         int ret, i;
1277
1278         /* Check number of tevs */
1279         if (tf->ntevs == tf->max_tevs) {
1280                 pr_warning("Too many( > %d) probe point found.\n",
1281                            tf->max_tevs);
1282                 return -ERANGE;
1283         }
1284         tev = &tf->tevs[tf->ntevs++];
1285
1286         /* Trace point should be converted from subprogram DIE */
1287         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1288                                      pp->retprobe, pp->function, &tev->point);
1289         if (ret < 0)
1290                 goto end;
1291
1292         tev->point.realname = strdup(dwarf_diename(sc_die));
1293         if (!tev->point.realname) {
1294                 ret = -ENOMEM;
1295                 goto end;
1296         }
1297
1298         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1299                  tev->point.offset);
1300
1301         /* Expand special probe argument if exist */
1302         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1303         if (args == NULL) {
1304                 ret = -ENOMEM;
1305                 goto end;
1306         }
1307
1308         ret = expand_probe_args(sc_die, pf, args);
1309         if (ret < 0)
1310                 goto end;
1311
1312         tev->nargs = ret;
1313         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1314         if (tev->args == NULL) {
1315                 ret = -ENOMEM;
1316                 goto end;
1317         }
1318
1319         /* Find each argument */
1320         for (i = 0; i < tev->nargs; i++) {
1321                 pf->pvar = &args[i];
1322                 pf->tvar = &tev->args[i];
1323                 /* Variable should be found from scope DIE */
1324                 ret = find_variable(sc_die, pf);
1325                 if (ret != 0)
1326                         break;
1327         }
1328
1329 end:
1330         if (ret) {
1331                 clear_probe_trace_event(tev);
1332                 tf->ntevs--;
1333         }
1334         free(args);
1335         return ret;
1336 }
1337
1338 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1339 int debuginfo__find_trace_events(struct debuginfo *dbg,
1340                                  struct perf_probe_event *pev,
1341                                  struct probe_trace_event **tevs)
1342 {
1343         struct trace_event_finder tf = {
1344                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1345                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1346         int ret, i;
1347
1348         /* Allocate result tevs array */
1349         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1350         if (*tevs == NULL)
1351                 return -ENOMEM;
1352
1353         tf.tevs = *tevs;
1354         tf.ntevs = 0;
1355
1356         ret = debuginfo__find_probes(dbg, &tf.pf);
1357         if (ret < 0 || tf.ntevs == 0) {
1358                 for (i = 0; i < tf.ntevs; i++)
1359                         clear_probe_trace_event(&tf.tevs[i]);
1360                 zfree(tevs);
1361                 return ret;
1362         }
1363
1364         return (ret < 0) ? ret : tf.ntevs;
1365 }
1366
1367 /* Collect available variables in this scope */
1368 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1369 {
1370         struct available_var_finder *af = data;
1371         struct variable_list *vl;
1372         struct strbuf buf = STRBUF_INIT;
1373         int tag, ret;
1374
1375         vl = &af->vls[af->nvls - 1];
1376
1377         tag = dwarf_tag(die_mem);
1378         if (tag == DW_TAG_formal_parameter ||
1379             tag == DW_TAG_variable) {
1380                 ret = convert_variable_location(die_mem, af->pf.addr,
1381                                                 af->pf.fb_ops, &af->pf.sp_die,
1382                                                 af->pf.machine, NULL);
1383                 if (ret == 0 || ret == -ERANGE) {
1384                         int ret2;
1385                         bool externs = !af->child;
1386
1387                         if (strbuf_init(&buf, 64) < 0)
1388                                 goto error;
1389
1390                         if (probe_conf.show_location_range) {
1391                                 if (!externs)
1392                                         ret2 = strbuf_add(&buf,
1393                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1394                                 else
1395                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1396                                 if (ret2)
1397                                         goto error;
1398                         }
1399
1400                         ret2 = die_get_varname(die_mem, &buf);
1401
1402                         if (!ret2 && probe_conf.show_location_range &&
1403                                 !externs) {
1404                                 if (strbuf_addch(&buf, '\t') < 0)
1405                                         goto error;
1406                                 ret2 = die_get_var_range(&af->pf.sp_die,
1407                                                         die_mem, &buf);
1408                         }
1409
1410                         pr_debug("Add new var: %s\n", buf.buf);
1411                         if (ret2 == 0) {
1412                                 strlist__add(vl->vars,
1413                                         strbuf_detach(&buf, NULL));
1414                         }
1415                         strbuf_release(&buf);
1416                 }
1417         }
1418
1419         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1420                 return DIE_FIND_CB_CONTINUE;
1421         else
1422                 return DIE_FIND_CB_SIBLING;
1423 error:
1424         strbuf_release(&buf);
1425         pr_debug("Error in strbuf\n");
1426         return DIE_FIND_CB_END;
1427 }
1428
1429 static bool available_var_finder_overlap(struct available_var_finder *af)
1430 {
1431         int i;
1432
1433         for (i = 0; i < af->nvls; i++) {
1434                 if (af->pf.addr == af->vls[i].point.address)
1435                         return true;
1436         }
1437         return false;
1438
1439 }
1440
1441 /* Add a found vars into available variables list */
1442 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1443 {
1444         struct available_var_finder *af =
1445                         container_of(pf, struct available_var_finder, pf);
1446         struct perf_probe_point *pp = &pf->pev->point;
1447         struct variable_list *vl;
1448         Dwarf_Die die_mem;
1449         int ret;
1450
1451         /*
1452          * For some reason (e.g. different column assigned to same address),
1453          * this callback can be called with the address which already passed.
1454          * Ignore it first.
1455          */
1456         if (available_var_finder_overlap(af))
1457                 return 0;
1458
1459         /* Check number of tevs */
1460         if (af->nvls == af->max_vls) {
1461                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1462                 return -ERANGE;
1463         }
1464         vl = &af->vls[af->nvls++];
1465
1466         /* Trace point should be converted from subprogram DIE */
1467         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1468                                      pp->retprobe, pp->function, &vl->point);
1469         if (ret < 0)
1470                 return ret;
1471
1472         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1473                  vl->point.offset);
1474
1475         /* Find local variables */
1476         vl->vars = strlist__new(NULL, NULL);
1477         if (vl->vars == NULL)
1478                 return -ENOMEM;
1479         af->child = true;
1480         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1481
1482         /* Find external variables */
1483         if (!probe_conf.show_ext_vars)
1484                 goto out;
1485         /* Don't need to search child DIE for external vars. */
1486         af->child = false;
1487         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1488
1489 out:
1490         if (strlist__empty(vl->vars)) {
1491                 strlist__delete(vl->vars);
1492                 vl->vars = NULL;
1493         }
1494
1495         return ret;
1496 }
1497
1498 /*
1499  * Find available variables at given probe point
1500  * Return the number of found probe points. Return 0 if there is no
1501  * matched probe point. Return <0 if an error occurs.
1502  */
1503 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1504                                       struct perf_probe_event *pev,
1505                                       struct variable_list **vls)
1506 {
1507         struct available_var_finder af = {
1508                         .pf = {.pev = pev, .callback = add_available_vars},
1509                         .mod = dbg->mod,
1510                         .max_vls = probe_conf.max_probes};
1511         int ret;
1512
1513         /* Allocate result vls array */
1514         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1515         if (*vls == NULL)
1516                 return -ENOMEM;
1517
1518         af.vls = *vls;
1519         af.nvls = 0;
1520
1521         ret = debuginfo__find_probes(dbg, &af.pf);
1522         if (ret < 0) {
1523                 /* Free vlist for error */
1524                 while (af.nvls--) {
1525                         zfree(&af.vls[af.nvls].point.symbol);
1526                         strlist__delete(af.vls[af.nvls].vars);
1527                 }
1528                 zfree(vls);
1529                 return ret;
1530         }
1531
1532         return (ret < 0) ? ret : af.nvls;
1533 }
1534
1535 /* For the kernel module, we need a special code to get a DIE */
1536 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1537                                 bool adjust_offset)
1538 {
1539         int n, i;
1540         Elf32_Word shndx;
1541         Elf_Scn *scn;
1542         Elf *elf;
1543         GElf_Shdr mem, *shdr;
1544         const char *p;
1545
1546         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1547         if (!elf)
1548                 return -EINVAL;
1549
1550         /* Get the number of relocations */
1551         n = dwfl_module_relocations(dbg->mod);
1552         if (n < 0)
1553                 return -ENOENT;
1554         /* Search the relocation related .text section */
1555         for (i = 0; i < n; i++) {
1556                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1557                 if (strcmp(p, ".text") == 0) {
1558                         /* OK, get the section header */
1559                         scn = elf_getscn(elf, shndx);
1560                         if (!scn)
1561                                 return -ENOENT;
1562                         shdr = gelf_getshdr(scn, &mem);
1563                         if (!shdr)
1564                                 return -ENOENT;
1565                         *offs = shdr->sh_addr;
1566                         if (adjust_offset)
1567                                 *offs -= shdr->sh_offset;
1568                 }
1569         }
1570         return 0;
1571 }
1572
1573 /* Reverse search */
1574 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1575                                 struct perf_probe_point *ppt)
1576 {
1577         Dwarf_Die cudie, spdie, indie;
1578         Dwarf_Addr _addr = 0, baseaddr = 0;
1579         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1580         int baseline = 0, lineno = 0, ret = 0;
1581
1582         /* We always need to relocate the address for aranges */
1583         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1584                 addr += baseaddr;
1585         /* Find cu die */
1586         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1587                 pr_warning("Failed to find debug information for address %lx\n",
1588                            addr);
1589                 ret = -EINVAL;
1590                 goto end;
1591         }
1592
1593         /* Find a corresponding line (filename and lineno) */
1594         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1595         /* Don't care whether it failed or not */
1596
1597         /* Find a corresponding function (name, baseline and baseaddr) */
1598         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1599                 /* Get function entry information */
1600                 func = basefunc = dwarf_diename(&spdie);
1601                 if (!func ||
1602                     die_entrypc(&spdie, &baseaddr) != 0 ||
1603                     dwarf_decl_line(&spdie, &baseline) != 0) {
1604                         lineno = 0;
1605                         goto post;
1606                 }
1607
1608                 fname = dwarf_decl_file(&spdie);
1609                 if (addr == (unsigned long)baseaddr) {
1610                         /* Function entry - Relative line number is 0 */
1611                         lineno = baseline;
1612                         goto post;
1613                 }
1614
1615                 /* Track down the inline functions step by step */
1616                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1617                                                 &indie)) {
1618                         /* There is an inline function */
1619                         if (die_entrypc(&indie, &_addr) == 0 &&
1620                             _addr == addr) {
1621                                 /*
1622                                  * addr is at an inline function entry.
1623                                  * In this case, lineno should be the call-site
1624                                  * line number. (overwrite lineinfo)
1625                                  */
1626                                 lineno = die_get_call_lineno(&indie);
1627                                 fname = die_get_call_file(&indie);
1628                                 break;
1629                         } else {
1630                                 /*
1631                                  * addr is in an inline function body.
1632                                  * Since lineno points one of the lines
1633                                  * of the inline function, baseline should
1634                                  * be the entry line of the inline function.
1635                                  */
1636                                 tmp = dwarf_diename(&indie);
1637                                 if (!tmp ||
1638                                     dwarf_decl_line(&indie, &baseline) != 0)
1639                                         break;
1640                                 func = tmp;
1641                                 spdie = indie;
1642                         }
1643                 }
1644                 /* Verify the lineno and baseline are in a same file */
1645                 tmp = dwarf_decl_file(&spdie);
1646                 if (!tmp || strcmp(tmp, fname) != 0)
1647                         lineno = 0;
1648         }
1649
1650 post:
1651         /* Make a relative line number or an offset */
1652         if (lineno)
1653                 ppt->line = lineno - baseline;
1654         else if (basefunc) {
1655                 ppt->offset = addr - (unsigned long)baseaddr;
1656                 func = basefunc;
1657         }
1658
1659         /* Duplicate strings */
1660         if (func) {
1661                 ppt->function = strdup(func);
1662                 if (ppt->function == NULL) {
1663                         ret = -ENOMEM;
1664                         goto end;
1665                 }
1666         }
1667         if (fname) {
1668                 ppt->file = strdup(fname);
1669                 if (ppt->file == NULL) {
1670                         zfree(&ppt->function);
1671                         ret = -ENOMEM;
1672                         goto end;
1673                 }
1674         }
1675 end:
1676         if (ret == 0 && (fname || func))
1677                 ret = 1;        /* Found a point */
1678         return ret;
1679 }
1680
1681 /* Add a line and store the src path */
1682 static int line_range_add_line(const char *src, unsigned int lineno,
1683                                struct line_range *lr)
1684 {
1685         /* Copy source path */
1686         if (!lr->path) {
1687                 lr->path = strdup(src);
1688                 if (lr->path == NULL)
1689                         return -ENOMEM;
1690         }
1691         return intlist__add(lr->line_list, lineno);
1692 }
1693
1694 static int line_range_walk_cb(const char *fname, int lineno,
1695                               Dwarf_Addr addr __maybe_unused,
1696                               void *data)
1697 {
1698         struct line_finder *lf = data;
1699         int err;
1700
1701         if ((strtailcmp(fname, lf->fname) != 0) ||
1702             (lf->lno_s > lineno || lf->lno_e < lineno))
1703                 return 0;
1704
1705         err = line_range_add_line(fname, lineno, lf->lr);
1706         if (err < 0 && err != -EEXIST)
1707                 return err;
1708
1709         return 0;
1710 }
1711
1712 /* Find line range from its line number */
1713 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1714 {
1715         int ret;
1716
1717         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1718
1719         /* Update status */
1720         if (ret >= 0)
1721                 if (!intlist__empty(lf->lr->line_list))
1722                         ret = lf->found = 1;
1723                 else
1724                         ret = 0;        /* Lines are not found */
1725         else {
1726                 zfree(&lf->lr->path);
1727         }
1728         return ret;
1729 }
1730
1731 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1732 {
1733         int ret = find_line_range_by_line(in_die, data);
1734
1735         /*
1736          * We have to check all instances of inlined function, because
1737          * some execution paths can be optimized out depends on the
1738          * function argument of instances. However, if an error occurs,
1739          * it should be handled by the caller.
1740          */
1741         return ret < 0 ? ret : 0;
1742 }
1743
1744 /* Search function definition from function name */
1745 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1746 {
1747         struct dwarf_callback_param *param = data;
1748         struct line_finder *lf = param->data;
1749         struct line_range *lr = lf->lr;
1750
1751         /* Check declared file */
1752         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1753                 return DWARF_CB_OK;
1754
1755         if (die_is_func_def(sp_die) &&
1756             die_match_name(sp_die, lr->function)) {
1757                 lf->fname = dwarf_decl_file(sp_die);
1758                 dwarf_decl_line(sp_die, &lr->offset);
1759                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1760                 lf->lno_s = lr->offset + lr->start;
1761                 if (lf->lno_s < 0)      /* Overflow */
1762                         lf->lno_s = INT_MAX;
1763                 lf->lno_e = lr->offset + lr->end;
1764                 if (lf->lno_e < 0)      /* Overflow */
1765                         lf->lno_e = INT_MAX;
1766                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1767                 lr->start = lf->lno_s;
1768                 lr->end = lf->lno_e;
1769                 if (!die_is_func_instance(sp_die))
1770                         param->retval = die_walk_instances(sp_die,
1771                                                 line_range_inline_cb, lf);
1772                 else
1773                         param->retval = find_line_range_by_line(sp_die, lf);
1774                 return DWARF_CB_ABORT;
1775         }
1776         return DWARF_CB_OK;
1777 }
1778
1779 static int find_line_range_by_func(struct line_finder *lf)
1780 {
1781         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1782         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1783         return param.retval;
1784 }
1785
1786 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1787 {
1788         struct line_finder lf = {.lr = lr, .found = 0};
1789         int ret = 0;
1790         Dwarf_Off off = 0, noff;
1791         size_t cuhl;
1792         Dwarf_Die *diep;
1793         const char *comp_dir;
1794
1795         /* Fastpath: lookup by function name from .debug_pubnames section */
1796         if (lr->function) {
1797                 struct pubname_callback_param pubname_param = {
1798                         .function = lr->function, .file = lr->file,
1799                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1800                 struct dwarf_callback_param line_range_param = {
1801                         .data = (void *)&lf, .retval = 0};
1802
1803                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1804                                   &pubname_param, 0);
1805                 if (pubname_param.found) {
1806                         line_range_search_cb(&lf.sp_die, &line_range_param);
1807                         if (lf.found)
1808                                 goto found;
1809                 }
1810         }
1811
1812         /* Loop on CUs (Compilation Unit) */
1813         while (!lf.found && ret >= 0) {
1814                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1815                                  NULL, NULL, NULL) != 0)
1816                         break;
1817
1818                 /* Get the DIE(Debugging Information Entry) of this CU */
1819                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1820                 if (!diep)
1821                         continue;
1822
1823                 /* Check if target file is included. */
1824                 if (lr->file)
1825                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1826                 else
1827                         lf.fname = 0;
1828
1829                 if (!lr->file || lf.fname) {
1830                         if (lr->function)
1831                                 ret = find_line_range_by_func(&lf);
1832                         else {
1833                                 lf.lno_s = lr->start;
1834                                 lf.lno_e = lr->end;
1835                                 ret = find_line_range_by_line(NULL, &lf);
1836                         }
1837                 }
1838                 off = noff;
1839         }
1840
1841 found:
1842         /* Store comp_dir */
1843         if (lf.found) {
1844                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1845                 if (comp_dir) {
1846                         lr->comp_dir = strdup(comp_dir);
1847                         if (!lr->comp_dir)
1848                                 ret = -ENOMEM;
1849                 }
1850         }
1851
1852         pr_debug("path: %s\n", lr->path);
1853         return (ret < 0) ? ret : lf.found;
1854 }
1855
1856 /*
1857  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1858  * and chop off leading directories that do not exist. Result is passed back as
1859  * a newly allocated path on success.
1860  * Return 0 if file was found and readable, -errno otherwise.
1861  */
1862 int get_real_path(const char *raw_path, const char *comp_dir,
1863                          char **new_path)
1864 {
1865         const char *prefix = symbol_conf.source_prefix;
1866
1867         if (!prefix) {
1868                 if (raw_path[0] != '/' && comp_dir)
1869                         /* If not an absolute path, try to use comp_dir */
1870                         prefix = comp_dir;
1871                 else {
1872                         if (access(raw_path, R_OK) == 0) {
1873                                 *new_path = strdup(raw_path);
1874                                 return *new_path ? 0 : -ENOMEM;
1875                         } else
1876                                 return -errno;
1877                 }
1878         }
1879
1880         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1881         if (!*new_path)
1882                 return -ENOMEM;
1883
1884         for (;;) {
1885                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1886
1887                 if (access(*new_path, R_OK) == 0)
1888                         return 0;
1889
1890                 if (!symbol_conf.source_prefix) {
1891                         /* In case of searching comp_dir, don't retry */
1892                         zfree(new_path);
1893                         return -errno;
1894                 }
1895
1896                 switch (errno) {
1897                 case ENAMETOOLONG:
1898                 case ENOENT:
1899                 case EROFS:
1900                 case EFAULT:
1901                         raw_path = strchr(++raw_path, '/');
1902                         if (!raw_path) {
1903                                 zfree(new_path);
1904                                 return -ENOENT;
1905                         }
1906                         continue;
1907
1908                 default:
1909                         zfree(new_path);
1910                         return -errno;
1911                 }
1912         }
1913 }