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