tools/perf/util/probe-finder.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * probe-finder.c : C expression to kprobe event converter
   4  *
   5  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   6  */
   7
   8 #include <inttypes.h>
   9 #include <sys/utsname.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <fcntl.h>
  13 #include <errno.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <stdarg.h>
  19 #include <dwarf-regs.h>
  20
  21 #include <linux/bitops.h>
  22 #include <linux/zalloc.h>
  23 #include "event.h"
  24 #include "dso.h"
  25 #include "debug.h"
  26 #include "intlist.h"
  27 #include "strbuf.h"
  28 #include "strlist.h"
  29 #include "symbol.h"
  30 #include "probe-finder.h"
  31 #include "probe-file.h"
  32 #include "string2.h"
  33
  34 /* Kprobe tracer basic type is up to u64 */
  35 #define MAX_BASIC_TYPE_BITS     64
  36
  37 /* Dwarf FL wrappers */
  38 static char *debuginfo_path;    /* Currently dummy */
  39
  40 static const Dwfl_Callbacks offline_callbacks = {
  41         .find_debuginfo = dwfl_standard_find_debuginfo,
  42         .debuginfo_path = &debuginfo_path,
  43
  44         .section_address = dwfl_offline_section_address,
  45
  46         /* We use this table for core files too.  */
  47         .find_elf = dwfl_build_id_find_elf,
  48 };
  49
  50 /* Get a Dwarf from offline image */
  51 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  52                                          const char *path)
  53 {
  54         int fd;
  55
  56         fd = open(path, O_RDONLY);
  57         if (fd < 0)
  58                 return fd;
  59
  60         dbg->dwfl = dwfl_begin(&offline_callbacks);
  61         if (!dbg->dwfl)
  62                 goto error;
  63
  64         dwfl_report_begin(dbg->dwfl);
  65         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  66         if (!dbg->mod)
  67                 goto error;
  68
  69         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  70         if (!dbg->dbg)
  71                 goto error;
  72
  73         dwfl_report_end(dbg->dwfl, NULL, NULL);
  74
  75         return 0;
  76 error:
  77         if (dbg->dwfl)
  78                 dwfl_end(dbg->dwfl);
  79         else
  80                 close(fd);
  81         memset(dbg, 0, sizeof(*dbg));
  82
  83         return -ENOENT;
  84 }
  85
  86 static struct debuginfo *__debuginfo__new(const char *path)
  87 {
  88         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  89         if (!dbg)
  90                 return NULL;
  91
  92         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  93                 zfree(&dbg);
  94         if (dbg)
  95                 pr_debug("Open Debuginfo file: %s\n", path);
  96         return dbg;
  97 }
  98
  99 enum dso_binary_type distro_dwarf_types[] = {
 100         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 101         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 102         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 103         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 104         DSO_BINARY_TYPE__NOT_FOUND,
 105 };
 106
 107 struct debuginfo *debuginfo__new(const char *path)
 108 {
 109         enum dso_binary_type *type;
 110         char buf[PATH_MAX], nil = '\0';
 111         struct dso *dso;
 112         struct debuginfo *dinfo = NULL;
 113
 114         /* Try to open distro debuginfo files */
 115         dso = dso__new(path);
 116         if (!dso)
 117                 goto out;
 118
 119         for (type = distro_dwarf_types;
 120              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 121              type++) {
 122                 if (dso__read_binary_type_filename(dso, *type, &nil,
 123                                                    buf, PATH_MAX) < 0)
 124                         continue;
 125                 dinfo = __debuginfo__new(buf);
 126         }
 127         dso__put(dso);
 128
 129 out:
 130         /* if failed to open all distro debuginfo, open given binary */
 131         return dinfo ? : __debuginfo__new(path);
 132 }
 133
 134 void debuginfo__delete(struct debuginfo *dbg)
 135 {
 136         if (dbg) {
 137                 if (dbg->dwfl)
 138                         dwfl_end(dbg->dwfl);
 139                 free(dbg);
 140         }
 141 }
 142
 143 /*
 144  * Probe finder related functions
 145  */
 146
 147 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 148 {
 149         struct probe_trace_arg_ref *ref;
 150         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 151         if (ref != NULL)
 152                 ref->offset = offs;
 153         return ref;
 154 }
 155
 156 /*
 157  * Convert a location into trace_arg.
 158  * If tvar == NULL, this just checks variable can be converted.
 159  * If fentry == true and vr_die is a parameter, do huristic search
 160  * for the location fuzzed by function entry mcount.
 161  */
 162 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 163                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 164                                      unsigned int machine,
 165                                      struct probe_trace_arg *tvar)
 166 {
 167         Dwarf_Attribute attr;
 168         Dwarf_Addr tmp = 0;
 169         Dwarf_Op *op;
 170         size_t nops;
 171         unsigned int regn;
 172         Dwarf_Word offs = 0;
 173         bool ref = false;
 174         const char *regs;
 175         int ret, ret2 = 0;
 176
 177         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 178                 goto static_var;
 179
 180         /* TODO: handle more than 1 exprs */
 181         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 182                 return -EINVAL; /* Broken DIE ? */
 183         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 184                 ret = dwarf_entrypc(sp_die, &tmp);
 185                 if (ret)
 186                         return -ENOENT;
 187
 188                 if (probe_conf.show_location_range &&
 189                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 190                         ret2 = -ERANGE;
 191                 } else if (addr != tmp ||
 192                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 193                         return -ENOENT;
 194                 }
 195
 196                 ret = dwarf_highpc(sp_die, &tmp);
 197                 if (ret)
 198                         return -ENOENT;
 199                 /*
 200                  * This is fuzzed by fentry mcount. We try to find the
 201                  * parameter location at the earliest address.
 202                  */
 203                 for (addr += 1; addr <= tmp; addr++) {
 204                         if (dwarf_getlocation_addr(&attr, addr, &op,
 205                                                    &nops, 1) > 0)
 206                                 goto found;
 207                 }
 208                 return -ENOENT;
 209         }
 210 found:
 211         if (nops == 0)
 212                 /* TODO: Support const_value */
 213                 return -ENOENT;
 214
 215         if (op->atom == DW_OP_addr) {
 216 static_var:
 217                 if (!tvar)
 218                         return ret2;
 219                 /* Static variables on memory (not stack), make @varname */
 220                 ret = strlen(dwarf_diename(vr_die));
 221                 tvar->value = zalloc(ret + 2);
 222                 if (tvar->value == NULL)
 223                         return -ENOMEM;
 224                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 225                 tvar->ref = alloc_trace_arg_ref((long)offs);
 226                 if (tvar->ref == NULL)
 227                         return -ENOMEM;
 228                 return ret2;
 229         }
 230
 231         /* If this is based on frame buffer, set the offset */
 232         if (op->atom == DW_OP_fbreg) {
 233                 if (fb_ops == NULL)
 234                         return -ENOTSUP;
 235                 ref = true;
 236                 offs = op->number;
 237                 op = &fb_ops[0];
 238         }
 239
 240         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 241                 regn = op->atom - DW_OP_breg0;
 242                 offs += op->number;
 243                 ref = true;
 244         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 245                 regn = op->atom - DW_OP_reg0;
 246         } else if (op->atom == DW_OP_bregx) {
 247                 regn = op->number;
 248                 offs += op->number2;
 249                 ref = true;
 250         } else if (op->atom == DW_OP_regx) {
 251                 regn = op->number;
 252         } else {
 253                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 254                 return -ENOTSUP;
 255         }
 256
 257         if (!tvar)
 258                 return ret2;
 259
 260         regs = get_dwarf_regstr(regn, machine);
 261         if (!regs) {
 262                 /* This should be a bug in DWARF or this tool */
 263                 pr_warning("Mapping for the register number %u "
 264                            "missing on this architecture.\n", regn);
 265                 return -ENOTSUP;
 266         }
 267
 268         tvar->value = strdup(regs);
 269         if (tvar->value == NULL)
 270                 return -ENOMEM;
 271
 272         if (ref) {
 273                 tvar->ref = alloc_trace_arg_ref((long)offs);
 274                 if (tvar->ref == NULL)
 275                         return -ENOMEM;
 276         }
 277         return ret2;
 278 }
 279
 280 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 281
 282 static int convert_variable_type(Dwarf_Die *vr_die,
 283                                  struct probe_trace_arg *tvar,
 284                                  const char *cast, bool user_access)
 285 {
 286         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 287         Dwarf_Die type;
 288         char buf[16];
 289         char sbuf[STRERR_BUFSIZE];
 290         int bsize, boffs, total;
 291         int ret;
 292         char prefix;
 293
 294         /* TODO: check all types */
 295         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 296             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 297                 /* Non string type is OK */
 298                 /* and respect signedness/hexadecimal cast */
 299                 tvar->type = strdup(cast);
 300                 return (tvar->type == NULL) ? -ENOMEM : 0;
 301         }
 302
 303         bsize = dwarf_bitsize(vr_die);
 304         if (bsize > 0) {
 305                 /* This is a bitfield */
 306                 boffs = dwarf_bitoffset(vr_die);
 307                 total = dwarf_bytesize(vr_die);
 308                 if (boffs < 0 || total < 0)
 309                         return -ENOENT;
 310                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 311                                 BYTES_TO_BITS(total));
 312                 goto formatted;
 313         }
 314
 315         if (die_get_real_type(vr_die, &type) == NULL) {
 316                 pr_warning("Failed to get a type information of %s.\n",
 317                            dwarf_diename(vr_die));
 318                 return -ENOENT;
 319         }
 320
 321         pr_debug("%s type is %s.\n",
 322                  dwarf_diename(vr_die), dwarf_diename(&type));
 323
 324         if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
 325                 /* String type */
 326                 ret = dwarf_tag(&type);
 327                 if (ret != DW_TAG_pointer_type &&
 328                     ret != DW_TAG_array_type) {
 329                         pr_warning("Failed to cast into string: "
 330                                    "%s(%s) is not a pointer nor array.\n",
 331                                    dwarf_diename(vr_die), dwarf_diename(&type));
 332                         return -EINVAL;
 333                 }
 334                 if (die_get_real_type(&type, &type) == NULL) {
 335                         pr_warning("Failed to get a type"
 336                                    " information.\n");
 337                         return -ENOENT;
 338                 }
 339                 if (ret == DW_TAG_pointer_type) {
 340                         while (*ref_ptr)
 341                                 ref_ptr = &(*ref_ptr)->next;
 342                         /* Add new reference with offset +0 */
 343                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 344                         if (*ref_ptr == NULL) {
 345                                 pr_warning("Out of memory error\n");
 346                                 return -ENOMEM;
 347                         }
 348                         (*ref_ptr)->user_access = user_access;
 349                 }
 350                 if (!die_compare_name(&type, "char") &&
 351                     !die_compare_name(&type, "unsigned char")) {
 352                         pr_warning("Failed to cast into string: "
 353                                    "%s is not (unsigned) char *.\n",
 354                                    dwarf_diename(vr_die));
 355                         return -EINVAL;
 356                 }
 357                 tvar->type = strdup(cast);
 358                 return (tvar->type == NULL) ? -ENOMEM : 0;
 359         }
 360
 361         if (cast && (strcmp(cast, "u") == 0))
 362                 prefix = 'u';
 363         else if (cast && (strcmp(cast, "s") == 0))
 364                 prefix = 's';
 365         else if (cast && (strcmp(cast, "x") == 0) &&
 366                  probe_type_is_available(PROBE_TYPE_X))
 367                 prefix = 'x';
 368         else
 369                 prefix = die_is_signed_type(&type) ? 's' :
 370                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 371
 372         ret = dwarf_bytesize(&type);
 373         if (ret <= 0)
 374                 /* No size ... try to use default type */
 375                 return 0;
 376         ret = BYTES_TO_BITS(ret);
 377
 378         /* Check the bitwidth */
 379         if (ret > MAX_BASIC_TYPE_BITS) {
 380                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 381                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 382                 ret = MAX_BASIC_TYPE_BITS;
 383         }
 384         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 385
 386 formatted:
 387         if (ret < 0 || ret >= 16) {
 388                 if (ret >= 16)
 389                         ret = -E2BIG;
 390                 pr_warning("Failed to convert variable type: %s\n",
 391                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 392                 return ret;
 393         }
 394         tvar->type = strdup(buf);
 395         if (tvar->type == NULL)
 396                 return -ENOMEM;
 397         return 0;
 398 }
 399
 400 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 401                                     struct perf_probe_arg_field *field,
 402                                     struct probe_trace_arg_ref **ref_ptr,
 403                                     Dwarf_Die *die_mem, bool user_access)
 404 {
 405         struct probe_trace_arg_ref *ref = *ref_ptr;
 406         Dwarf_Die type;
 407         Dwarf_Word offs;
 408         int ret, tag;
 409
 410         pr_debug("converting %s in %s\n", field->name, varname);
 411         if (die_get_real_type(vr_die, &type) == NULL) {
 412                 pr_warning("Failed to get the type of %s.\n", varname);
 413                 return -ENOENT;
 414         }
 415         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 416                   (unsigned)dwarf_dieoffset(&type));
 417         tag = dwarf_tag(&type);
 418
 419         if (field->name[0] == '[' &&
 420             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 421                 /* Save original type for next field or type */
 422                 memcpy(die_mem, &type, sizeof(*die_mem));
 423                 /* Get the type of this array */
 424                 if (die_get_real_type(&type, &type) == NULL) {
 425                         pr_warning("Failed to get the type of %s.\n", varname);
 426                         return -ENOENT;
 427                 }
 428                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 429                          (unsigned)dwarf_dieoffset(&type));
 430                 if (tag == DW_TAG_pointer_type) {
 431                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 432                         if (ref == NULL)
 433                                 return -ENOMEM;
 434                         if (*ref_ptr)
 435                                 (*ref_ptr)->next = ref;
 436                         else
 437                                 *ref_ptr = ref;
 438                 }
 439                 ref->offset += dwarf_bytesize(&type) * field->index;
 440                 ref->user_access = user_access;
 441                 goto next;
 442         } else if (tag == DW_TAG_pointer_type) {
 443                 /* Check the pointer and dereference */
 444                 if (!field->ref) {
 445                         pr_err("Semantic error: %s must be referred by '->'\n",
 446                                field->name);
 447                         return -EINVAL;
 448                 }
 449                 /* Get the type pointed by this pointer */
 450                 if (die_get_real_type(&type, &type) == NULL) {
 451                         pr_warning("Failed to get the type of %s.\n", varname);
 452                         return -ENOENT;
 453                 }
 454                 /* Verify it is a data structure  */
 455                 tag = dwarf_tag(&type);
 456                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 457                         pr_warning("%s is not a data structure nor a union.\n",
 458                                    varname);
 459                         return -EINVAL;
 460                 }
 461
 462                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 463                 if (ref == NULL)
 464                         return -ENOMEM;
 465                 if (*ref_ptr)
 466                         (*ref_ptr)->next = ref;
 467                 else
 468                         *ref_ptr = ref;
 469         } else {
 470                 /* Verify it is a data structure  */
 471                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 472                         pr_warning("%s is not a data structure nor a union.\n",
 473                                    varname);
 474                         return -EINVAL;
 475                 }
 476                 if (field->name[0] == '[') {
 477                         pr_err("Semantic error: %s is not a pointer"
 478                                " nor array.\n", varname);
 479                         return -EINVAL;
 480                 }
 481                 /* While prcessing unnamed field, we don't care about this */
 482                 if (field->ref && dwarf_diename(vr_die)) {
 483                         pr_err("Semantic error: %s must be referred by '.'\n",
 484                                field->name);
 485                         return -EINVAL;
 486                 }
 487                 if (!ref) {
 488                         pr_warning("Structure on a register is not "
 489                                    "supported yet.\n");
 490                         return -ENOTSUP;
 491                 }
 492         }
 493
 494         if (die_find_member(&type, field->name, die_mem) == NULL) {
 495                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 496                            dwarf_diename(&type), field->name);
 497                 return -EINVAL;
 498         }
 499
 500         /* Get the offset of the field */
 501         if (tag == DW_TAG_union_type) {
 502                 offs = 0;
 503         } else {
 504                 ret = die_get_data_member_location(die_mem, &offs);
 505                 if (ret < 0) {
 506                         pr_warning("Failed to get the offset of %s.\n",
 507                                    field->name);
 508                         return ret;
 509                 }
 510         }
 511         ref->offset += (long)offs;
 512         ref->user_access = user_access;
 513
 514         /* If this member is unnamed, we need to reuse this field */
 515         if (!dwarf_diename(die_mem))
 516                 return convert_variable_fields(die_mem, varname, field,
 517                                                 &ref, die_mem, user_access);
 518
 519 next:
 520         /* Converting next field */
 521         if (field->next)
 522                 return convert_variable_fields(die_mem, field->name,
 523                                 field->next, &ref, die_mem, user_access);
 524         else
 525                 return 0;
 526 }
 527
 528 /* Show a variables in kprobe event format */
 529 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 530 {
 531         Dwarf_Die die_mem;
 532         int ret;
 533
 534         pr_debug("Converting variable %s into trace event.\n",
 535                  dwarf_diename(vr_die));
 536
 537         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 538                                         &pf->sp_die, pf->machine, pf->tvar);
 539         if (ret == -ENOENT || ret == -EINVAL) {
 540                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 541                        " Perhaps it has been optimized out.\n"
 542                        " Use -V with the --range option to show '%s' location range.\n",
 543                        pf->pvar->var, pf->pvar->var);
 544         } else if (ret == -ENOTSUP)
 545                 pr_err("Sorry, we don't support this variable location yet.\n");
 546         else if (ret == 0 && pf->pvar->field) {
 547                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 548                                               pf->pvar->field, &pf->tvar->ref,
 549                                               &die_mem, pf->pvar->user_access);
 550                 vr_die = &die_mem;
 551         }
 552         if (ret == 0)
 553                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
 554                                             pf->pvar->user_access);
 555         /* *expr will be cached in libdw. Don't free it. */
 556         return ret;
 557 }
 558
 559 /* Find a variable in a scope DIE */
 560 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 561 {
 562         Dwarf_Die vr_die;
 563         char *buf, *ptr;
 564         int ret = 0;
 565
 566         /* Copy raw parameters */
 567         if (!is_c_varname(pf->pvar->var))
 568                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 569
 570         if (pf->pvar->name)
 571                 pf->tvar->name = strdup(pf->pvar->name);
 572         else {
 573                 buf = synthesize_perf_probe_arg(pf->pvar);
 574                 if (!buf)
 575                         return -ENOMEM;
 576                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 577                 if (ptr)
 578                         *ptr = '_';
 579                 pf->tvar->name = buf;
 580         }
 581         if (pf->tvar->name == NULL)
 582                 return -ENOMEM;
 583
 584         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 585         /* Search child die for local variables and parameters. */
 586         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 587                 /* Search again in global variables */
 588                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 589                                                 0, &vr_die)) {
 590                         pr_warning("Failed to find '%s' in this function.\n",
 591                                    pf->pvar->var);
 592                         ret = -ENOENT;
 593                 }
 594         }
 595         if (ret >= 0)
 596                 ret = convert_variable(&vr_die, pf);
 597
 598         return ret;
 599 }
 600
 601 /* Convert subprogram DIE to trace point */
 602 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 603                                   Dwarf_Addr paddr, bool retprobe,
 604                                   const char *function,
 605                                   struct probe_trace_point *tp)
 606 {
 607         Dwarf_Addr eaddr;
 608         GElf_Sym sym;
 609         const char *symbol;
 610
 611         /* Verify the address is correct */
 612         if (!dwarf_haspc(sp_die, paddr)) {
 613                 pr_warning("Specified offset is out of %s\n",
 614                            dwarf_diename(sp_die));
 615                 return -EINVAL;
 616         }
 617
 618         /* Try to get actual symbol name from symtab */
 619         symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 620         if (!symbol) {
 621                 pr_warning("Failed to find symbol at 0x%lx\n",
 622                            (unsigned long)paddr);
 623                 return -ENOENT;
 624         }
 625         eaddr = sym.st_value;
 626
 627         tp->offset = (unsigned long)(paddr - eaddr);
 628         tp->address = (unsigned long)paddr;
 629         tp->symbol = strdup(symbol);
 630         if (!tp->symbol)
 631                 return -ENOMEM;
 632
 633         /* Return probe must be on the head of a subprogram */
 634         if (retprobe) {
 635                 if (eaddr != paddr) {
 636                         pr_warning("Failed to find \"%s%%return\",\n"
 637                                    " because %s is an inlined function and"
 638                                    " has no return point.\n", function,
 639                                    function);
 640                         return -EINVAL;
 641                 }
 642                 tp->retprobe = true;
 643         }
 644
 645         return 0;
 646 }
 647
 648 /* Call probe_finder callback with scope DIE */
 649 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 650 {
 651         Dwarf_Attribute fb_attr;
 652         Dwarf_Frame *frame = NULL;
 653         size_t nops;
 654         int ret;
 655
 656         if (!sc_die) {
 657                 pr_err("Caller must pass a scope DIE. Program error.\n");
 658                 return -EINVAL;
 659         }
 660
 661         /* If not a real subprogram, find a real one */
 662         if (!die_is_func_def(sc_die)) {
 663                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 664                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 665                                 pr_warning("Ignoring tail call from %s\n",
 666                                                 dwarf_diename(&pf->sp_die));
 667                                 return 0;
 668                         } else {
 669                                 pr_warning("Failed to find probe point in any "
 670                                            "functions.\n");
 671                                 return -ENOENT;
 672                         }
 673                 }
 674         } else
 675                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 676
 677         /* Get the frame base attribute/ops from subprogram */
 678         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 679         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 680         if (ret <= 0 || nops == 0) {
 681                 pf->fb_ops = NULL;
 682 #if _ELFUTILS_PREREQ(0, 142)
 683         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 684                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 685                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 686                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 687                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 688                         pr_warning("Failed to get call frame on 0x%jx\n",
 689                                    (uintmax_t)pf->addr);
 690                         free(frame);
 691                         return -ENOENT;
 692                 }
 693 #endif
 694         }
 695
 696         /* Call finder's callback handler */
 697         ret = pf->callback(sc_die, pf);
 698
 699         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 700         free(frame);
 701         pf->fb_ops = NULL;
 702
 703         return ret;
 704 }
 705
 706 struct find_scope_param {
 707         const char *function;
 708         const char *file;
 709         int line;
 710         int diff;
 711         Dwarf_Die *die_mem;
 712         bool found;
 713 };
 714
 715 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 716 {
 717         struct find_scope_param *fsp = data;
 718         const char *file;
 719         int lno;
 720
 721         /* Skip if declared file name does not match */
 722         if (fsp->file) {
 723                 file = dwarf_decl_file(fn_die);
 724                 if (!file || strcmp(fsp->file, file) != 0)
 725                         return 0;
 726         }
 727         /* If the function name is given, that's what user expects */
 728         if (fsp->function) {
 729                 if (die_match_name(fn_die, fsp->function)) {
 730                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 731                         fsp->found = true;
 732                         return 1;
 733                 }
 734         } else {
 735                 /* With the line number, find the nearest declared DIE */
 736                 dwarf_decl_line(fn_die, &lno);
 737                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 738                         /* Keep a candidate and continue */
 739                         fsp->diff = fsp->line - lno;
 740                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 741                         fsp->found = true;
 742                 }
 743         }
 744         return 0;
 745 }
 746
 747 /* Find an appropriate scope fits to given conditions */
 748 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 749 {
 750         struct find_scope_param fsp = {
 751                 .function = pf->pev->point.function,
 752                 .file = pf->fname,
 753                 .line = pf->lno,
 754                 .diff = INT_MAX,
 755                 .die_mem = die_mem,
 756                 .found = false,
 757         };
 758
 759         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 760
 761         return fsp.found ? die_mem : NULL;
 762 }
 763
 764 static int probe_point_line_walker(const char *fname, int lineno,
 765                                    Dwarf_Addr addr, void *data)
 766 {
 767         struct probe_finder *pf = data;
 768         Dwarf_Die *sc_die, die_mem;
 769         int ret;
 770
 771         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 772                 return 0;
 773
 774         pf->addr = addr;
 775         sc_die = find_best_scope(pf, &die_mem);
 776         if (!sc_die) {
 777                 pr_warning("Failed to find scope of probe point.\n");
 778                 return -ENOENT;
 779         }
 780
 781         ret = call_probe_finder(sc_die, pf);
 782
 783         /* Continue if no error, because the line will be in inline function */
 784         return ret < 0 ? ret : 0;
 785 }
 786
 787 /* Find probe point from its line number */
 788 static int find_probe_point_by_line(struct probe_finder *pf)
 789 {
 790         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 791 }
 792
 793 /* Find lines which match lazy pattern */
 794 static int find_lazy_match_lines(struct intlist *list,
 795                                  const char *fname, const char *pat)
 796 {
 797         FILE *fp;
 798         char *line = NULL;
 799         size_t line_len;
 800         ssize_t len;
 801         int count = 0, linenum = 1;
 802         char sbuf[STRERR_BUFSIZE];
 803
 804         fp = fopen(fname, "r");
 805         if (!fp) {
 806                 pr_warning("Failed to open %s: %s\n", fname,
 807                            str_error_r(errno, sbuf, sizeof(sbuf)));
 808                 return -errno;
 809         }
 810
 811         while ((len = getline(&line, &line_len, fp)) > 0) {
 812
 813                 if (line[len - 1] == '\n')
 814                         line[len - 1] = '\0';
 815
 816                 if (strlazymatch(line, pat)) {
 817                         intlist__add(list, linenum);
 818                         count++;
 819                 }
 820                 linenum++;
 821         }
 822
 823         if (ferror(fp))
 824                 count = -errno;
 825         free(line);
 826         fclose(fp);
 827
 828         if (count == 0)
 829                 pr_debug("No matched lines found in %s.\n", fname);
 830         return count;
 831 }
 832
 833 static int probe_point_lazy_walker(const char *fname, int lineno,
 834                                    Dwarf_Addr addr, void *data)
 835 {
 836         struct probe_finder *pf = data;
 837         Dwarf_Die *sc_die, die_mem;
 838         int ret;
 839
 840         if (!intlist__has_entry(pf->lcache, lineno) ||
 841             strtailcmp(fname, pf->fname) != 0)
 842                 return 0;
 843
 844         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 845                  lineno, (unsigned long long)addr);
 846         pf->addr = addr;
 847         pf->lno = lineno;
 848         sc_die = find_best_scope(pf, &die_mem);
 849         if (!sc_die) {
 850                 pr_warning("Failed to find scope of probe point.\n");
 851                 return -ENOENT;
 852         }
 853
 854         ret = call_probe_finder(sc_die, pf);
 855
 856         /*
 857          * Continue if no error, because the lazy pattern will match
 858          * to other lines
 859          */
 860         return ret < 0 ? ret : 0;
 861 }
 862
 863 /* Find probe points from lazy pattern  */
 864 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 865 {
 866         int ret = 0;
 867         char *fpath;
 868
 869         if (intlist__empty(pf->lcache)) {
 870                 const char *comp_dir;
 871
 872                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 873                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 874                 if (ret < 0) {
 875                         pr_warning("Failed to find source file path.\n");
 876                         return ret;
 877                 }
 878
 879                 /* Matching lazy line pattern */
 880                 ret = find_lazy_match_lines(pf->lcache, fpath,
 881                                             pf->pev->point.lazy_line);
 882                 free(fpath);
 883                 if (ret <= 0)
 884                         return ret;
 885         }
 886
 887         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 888 }
 889
 890 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 891 {
 892         struct perf_probe_point *pp = &pf->pev->point;
 893
 894         /* Not uprobe? */
 895         if (!pf->pev->uprobes)
 896                 return;
 897
 898         /* Compiled with optimization? */
 899         if (die_is_optimized_target(&pf->cu_die))
 900                 return;
 901
 902         /* Don't know entrypc? */
 903         if (!pf->addr)
 904                 return;
 905
 906         /* Only FUNC and FUNC@SRC are eligible. */
 907         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 908             pp->offset || pp->abs_address)
 909                 return;
 910
 911         /* Not interested in func parameter? */
 912         if (!perf_probe_with_var(pf->pev))
 913                 return;
 914
 915         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 916                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 917                 pf->addr);
 918
 919         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 920 }
 921
 922 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 923 {
 924         struct probe_finder *pf = data;
 925         struct perf_probe_point *pp = &pf->pev->point;
 926         Dwarf_Addr addr;
 927         int ret;
 928
 929         if (pp->lazy_line)
 930                 ret = find_probe_point_lazy(in_die, pf);
 931         else {
 932                 /* Get probe address */
 933                 if (dwarf_entrypc(in_die, &addr) != 0) {
 934                         pr_warning("Failed to get entry address of %s.\n",
 935                                    dwarf_diename(in_die));
 936                         return -ENOENT;
 937                 }
 938                 if (addr == 0) {
 939                         pr_debug("%s has no valid entry address. skipped.\n",
 940                                  dwarf_diename(in_die));
 941                         return -ENOENT;
 942                 }
 943                 pf->addr = addr;
 944                 pf->addr += pp->offset;
 945                 pr_debug("found inline addr: 0x%jx\n",
 946                          (uintmax_t)pf->addr);
 947
 948                 ret = call_probe_finder(in_die, pf);
 949         }
 950
 951         return ret;
 952 }
 953
 954 /* Callback parameter with return value for libdw */
 955 struct dwarf_callback_param {
 956         void *data;
 957         int retval;
 958 };
 959
 960 /* Search function from function name */
 961 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 962 {
 963         struct dwarf_callback_param *param = data;
 964         struct probe_finder *pf = param->data;
 965         struct perf_probe_point *pp = &pf->pev->point;
 966
 967         /* Check tag and diename */
 968         if (!die_is_func_def(sp_die) ||
 969             !die_match_name(sp_die, pp->function))
 970                 return DWARF_CB_OK;
 971
 972         /* Check declared file */
 973         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 974                 return DWARF_CB_OK;
 975
 976         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
 977                  (unsigned long)dwarf_dieoffset(sp_die));
 978         pf->fname = dwarf_decl_file(sp_die);
 979         if (pp->line) { /* Function relative line */
 980                 dwarf_decl_line(sp_die, &pf->lno);
 981                 pf->lno += pp->line;
 982                 param->retval = find_probe_point_by_line(pf);
 983         } else if (die_is_func_instance(sp_die)) {
 984                 /* Instances always have the entry address */
 985                 dwarf_entrypc(sp_die, &pf->addr);
 986                 /* But in some case the entry address is 0 */
 987                 if (pf->addr == 0) {
 988                         pr_debug("%s has no entry PC. Skipped\n",
 989                                  dwarf_diename(sp_die));
 990                         param->retval = 0;
 991                 /* Real function */
 992                 } else if (pp->lazy_line)
 993                         param->retval = find_probe_point_lazy(sp_die, pf);
 994                 else {
 995                         skip_prologue(sp_die, pf);
 996                         pf->addr += pp->offset;
 997                         /* TODO: Check the address in this function */
 998                         param->retval = call_probe_finder(sp_die, pf);
 999                 }
1000         } else if (!probe_conf.no_inlines) {
1001                 /* Inlined function: search instances */
1002                 param->retval = die_walk_instances(sp_die,
1003                                         probe_point_inline_cb, (void *)pf);
1004                 /* This could be a non-existed inline definition */
1005                 if (param->retval == -ENOENT)
1006                         param->retval = 0;
1007         }
1008
1009         /* We need to find other candidates */
1010         if (strisglob(pp->function) && param->retval >= 0) {
1011                 param->retval = 0;      /* We have to clear the result */
1012                 return DWARF_CB_OK;
1013         }
1014
1015         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1016 }
1017
1018 static int find_probe_point_by_func(struct probe_finder *pf)
1019 {
1020         struct dwarf_callback_param _param = {.data = (void *)pf,
1021                                               .retval = 0};
1022         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1023         return _param.retval;
1024 }
1025
1026 struct pubname_callback_param {
1027         char *function;
1028         char *file;
1029         Dwarf_Die *cu_die;
1030         Dwarf_Die *sp_die;
1031         int found;
1032 };
1033
1034 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1035 {
1036         struct pubname_callback_param *param = data;
1037
1038         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1039                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1040                         return DWARF_CB_OK;
1041
1042                 if (die_match_name(param->sp_die, param->function)) {
1043                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1044                                 return DWARF_CB_OK;
1045
1046                         if (param->file &&
1047                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1048                                 return DWARF_CB_OK;
1049
1050                         param->found = 1;
1051                         return DWARF_CB_ABORT;
1052                 }
1053         }
1054
1055         return DWARF_CB_OK;
1056 }
1057
1058 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1059                                   struct probe_finder *pf)
1060 {
1061         struct perf_probe_point *pp = &pf->pev->point;
1062         Dwarf_Off off, noff;
1063         size_t cuhl;
1064         Dwarf_Die *diep;
1065         int ret = 0;
1066
1067         off = 0;
1068         pf->lcache = intlist__new(NULL);
1069         if (!pf->lcache)
1070                 return -ENOMEM;
1071
1072         /* Fastpath: lookup by function name from .debug_pubnames section */
1073         if (pp->function && !strisglob(pp->function)) {
1074                 struct pubname_callback_param pubname_param = {
1075                         .function = pp->function,
1076                         .file     = pp->file,
1077                         .cu_die   = &pf->cu_die,
1078                         .sp_die   = &pf->sp_die,
1079                         .found    = 0,
1080                 };
1081                 struct dwarf_callback_param probe_param = {
1082                         .data = pf,
1083                 };
1084
1085                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1086                                   &pubname_param, 0);
1087                 if (pubname_param.found) {
1088                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1089                         if (ret)
1090                                 goto found;
1091                 }
1092         }
1093
1094         /* Loop on CUs (Compilation Unit) */
1095         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1096                 /* Get the DIE(Debugging Information Entry) of this CU */
1097                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1098                 if (!diep)
1099                         continue;
1100
1101                 /* Check if target file is included. */
1102                 if (pp->file)
1103                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1104                 else
1105                         pf->fname = NULL;
1106
1107                 if (!pp->file || pf->fname) {
1108                         if (pp->function)
1109                                 ret = find_probe_point_by_func(pf);
1110                         else if (pp->lazy_line)
1111                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1112                         else {
1113                                 pf->lno = pp->line;
1114                                 ret = find_probe_point_by_line(pf);
1115                         }
1116                         if (ret < 0)
1117                                 break;
1118                 }
1119                 off = noff;
1120         }
1121
1122 found:
1123         intlist__delete(pf->lcache);
1124         pf->lcache = NULL;
1125
1126         return ret;
1127 }
1128
1129 /* Find probe points from debuginfo */
1130 static int debuginfo__find_probes(struct debuginfo *dbg,
1131                                   struct probe_finder *pf)
1132 {
1133         int ret = 0;
1134         Elf *elf;
1135         GElf_Ehdr ehdr;
1136
1137         if (pf->cfi_eh || pf->cfi_dbg)
1138                 return debuginfo__find_probe_location(dbg, pf);
1139
1140         /* Get the call frame information from this dwarf */
1141         elf = dwarf_getelf(dbg->dbg);
1142         if (elf == NULL)
1143                 return -EINVAL;
1144
1145         if (gelf_getehdr(elf, &ehdr) == NULL)
1146                 return -EINVAL;
1147
1148         pf->machine = ehdr.e_machine;
1149
1150 #if _ELFUTILS_PREREQ(0, 142)
1151         do {
1152                 GElf_Shdr shdr;
1153
1154                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1155                     shdr.sh_type == SHT_PROGBITS)
1156                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1157
1158                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1159         } while (0);
1160 #endif
1161
1162         ret = debuginfo__find_probe_location(dbg, pf);
1163         return ret;
1164 }
1165
1166 struct local_vars_finder {
1167         struct probe_finder *pf;
1168         struct perf_probe_arg *args;
1169         bool vars;
1170         int max_args;
1171         int nargs;
1172         int ret;
1173 };
1174
1175 /* Collect available variables in this scope */
1176 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1177 {
1178         struct local_vars_finder *vf = data;
1179         struct probe_finder *pf = vf->pf;
1180         int tag;
1181
1182         tag = dwarf_tag(die_mem);
1183         if (tag == DW_TAG_formal_parameter ||
1184             (tag == DW_TAG_variable && vf->vars)) {
1185                 if (convert_variable_location(die_mem, vf->pf->addr,
1186                                               vf->pf->fb_ops, &pf->sp_die,
1187                                               pf->machine, NULL) == 0) {
1188                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1189                         if (vf->args[vf->nargs].var == NULL) {
1190                                 vf->ret = -ENOMEM;
1191                                 return DIE_FIND_CB_END;
1192                         }
1193                         pr_debug(" %s", vf->args[vf->nargs].var);
1194                         vf->nargs++;
1195                 }
1196         }
1197
1198         if (dwarf_haspc(die_mem, vf->pf->addr))
1199                 return DIE_FIND_CB_CONTINUE;
1200         else
1201                 return DIE_FIND_CB_SIBLING;
1202 }
1203
1204 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1205                              struct perf_probe_arg *args)
1206 {
1207         Dwarf_Die die_mem;
1208         int i;
1209         int n = 0;
1210         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1211                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1212
1213         for (i = 0; i < pf->pev->nargs; i++) {
1214                 /* var never be NULL */
1215                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1216                         vf.vars = true;
1217                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1218                         /* Copy normal argument */
1219                         args[n] = pf->pev->args[i];
1220                         n++;
1221                         continue;
1222                 }
1223                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1224                 vf.nargs = n;
1225                 /* Special local variables */
1226                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1227                                &die_mem);
1228                 pr_debug(" (%d)\n", vf.nargs - n);
1229                 if (vf.ret < 0)
1230                         return vf.ret;
1231                 n = vf.nargs;
1232         }
1233         return n;
1234 }
1235
1236 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1237 {
1238         int i;
1239
1240         for (i = 0; i < tf->ntevs; i++) {
1241                 if (tf->pf.addr == tf->tevs[i].point.address)
1242                         return true;
1243         }
1244         return false;
1245 }
1246
1247 /* Add a found probe point into trace event list */
1248 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1249 {
1250         struct trace_event_finder *tf =
1251                         container_of(pf, struct trace_event_finder, pf);
1252         struct perf_probe_point *pp = &pf->pev->point;
1253         struct probe_trace_event *tev;
1254         struct perf_probe_arg *args = NULL;
1255         int ret, i;
1256
1257         /*
1258          * For some reason (e.g. different column assigned to same address)
1259          * This callback can be called with the address which already passed.
1260          * Ignore it first.
1261          */
1262         if (trace_event_finder_overlap(tf))
1263                 return 0;
1264
1265         /* Check number of tevs */
1266         if (tf->ntevs == tf->max_tevs) {
1267                 pr_warning("Too many( > %d) probe point found.\n",
1268                            tf->max_tevs);
1269                 return -ERANGE;
1270         }
1271         tev = &tf->tevs[tf->ntevs++];
1272
1273         /* Trace point should be converted from subprogram DIE */
1274         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1275                                      pp->retprobe, pp->function, &tev->point);
1276         if (ret < 0)
1277                 goto end;
1278
1279         tev->point.realname = strdup(dwarf_diename(sc_die));
1280         if (!tev->point.realname) {
1281                 ret = -ENOMEM;
1282                 goto end;
1283         }
1284
1285         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1286                  tev->point.offset);
1287
1288         /* Expand special probe argument if exist */
1289         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1290         if (args == NULL) {
1291                 ret = -ENOMEM;
1292                 goto end;
1293         }
1294
1295         ret = expand_probe_args(sc_die, pf, args);
1296         if (ret < 0)
1297                 goto end;
1298
1299         tev->nargs = ret;
1300         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1301         if (tev->args == NULL) {
1302                 ret = -ENOMEM;
1303                 goto end;
1304         }
1305
1306         /* Find each argument */
1307         for (i = 0; i < tev->nargs; i++) {
1308                 pf->pvar = &args[i];
1309                 pf->tvar = &tev->args[i];
1310                 /* Variable should be found from scope DIE */
1311                 ret = find_variable(sc_die, pf);
1312                 if (ret != 0)
1313                         break;
1314         }
1315
1316 end:
1317         if (ret) {
1318                 clear_probe_trace_event(tev);
1319                 tf->ntevs--;
1320         }
1321         free(args);
1322         return ret;
1323 }
1324
1325 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1326 int debuginfo__find_trace_events(struct debuginfo *dbg,
1327                                  struct perf_probe_event *pev,
1328                                  struct probe_trace_event **tevs)
1329 {
1330         struct trace_event_finder tf = {
1331                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1332                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1333         int ret, i;
1334
1335         /* Allocate result tevs array */
1336         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1337         if (*tevs == NULL)
1338                 return -ENOMEM;
1339
1340         tf.tevs = *tevs;
1341         tf.ntevs = 0;
1342
1343         ret = debuginfo__find_probes(dbg, &tf.pf);
1344         if (ret < 0) {
1345                 for (i = 0; i < tf.ntevs; i++)
1346                         clear_probe_trace_event(&tf.tevs[i]);
1347                 zfree(tevs);
1348                 return ret;
1349         }
1350
1351         return (ret < 0) ? ret : tf.ntevs;
1352 }
1353
1354 /* Collect available variables in this scope */
1355 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1356 {
1357         struct available_var_finder *af = data;
1358         struct variable_list *vl;
1359         struct strbuf buf = STRBUF_INIT;
1360         int tag, ret;
1361
1362         vl = &af->vls[af->nvls - 1];
1363
1364         tag = dwarf_tag(die_mem);
1365         if (tag == DW_TAG_formal_parameter ||
1366             tag == DW_TAG_variable) {
1367                 ret = convert_variable_location(die_mem, af->pf.addr,
1368                                                 af->pf.fb_ops, &af->pf.sp_die,
1369                                                 af->pf.machine, NULL);
1370                 if (ret == 0 || ret == -ERANGE) {
1371                         int ret2;
1372                         bool externs = !af->child;
1373
1374                         if (strbuf_init(&buf, 64) < 0)
1375                                 goto error;
1376
1377                         if (probe_conf.show_location_range) {
1378                                 if (!externs)
1379                                         ret2 = strbuf_add(&buf,
1380                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1381                                 else
1382                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1383                                 if (ret2)
1384                                         goto error;
1385                         }
1386
1387                         ret2 = die_get_varname(die_mem, &buf);
1388
1389                         if (!ret2 && probe_conf.show_location_range &&
1390                                 !externs) {
1391                                 if (strbuf_addch(&buf, '\t') < 0)
1392                                         goto error;
1393                                 ret2 = die_get_var_range(&af->pf.sp_die,
1394                                                         die_mem, &buf);
1395                         }
1396
1397                         pr_debug("Add new var: %s\n", buf.buf);
1398                         if (ret2 == 0) {
1399                                 strlist__add(vl->vars,
1400                                         strbuf_detach(&buf, NULL));
1401                         }
1402                         strbuf_release(&buf);
1403                 }
1404         }
1405
1406         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1407                 return DIE_FIND_CB_CONTINUE;
1408         else
1409                 return DIE_FIND_CB_SIBLING;
1410 error:
1411         strbuf_release(&buf);
1412         pr_debug("Error in strbuf\n");
1413         return DIE_FIND_CB_END;
1414 }
1415
1416 /* Add a found vars into available variables list */
1417 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1418 {
1419         struct available_var_finder *af =
1420                         container_of(pf, struct available_var_finder, pf);
1421         struct perf_probe_point *pp = &pf->pev->point;
1422         struct variable_list *vl;
1423         Dwarf_Die die_mem;
1424         int ret;
1425
1426         /* Check number of tevs */
1427         if (af->nvls == af->max_vls) {
1428                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1429                 return -ERANGE;
1430         }
1431         vl = &af->vls[af->nvls++];
1432
1433         /* Trace point should be converted from subprogram DIE */
1434         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1435                                      pp->retprobe, pp->function, &vl->point);
1436         if (ret < 0)
1437                 return ret;
1438
1439         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1440                  vl->point.offset);
1441
1442         /* Find local variables */
1443         vl->vars = strlist__new(NULL, NULL);
1444         if (vl->vars == NULL)
1445                 return -ENOMEM;
1446         af->child = true;
1447         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1448
1449         /* Find external variables */
1450         if (!probe_conf.show_ext_vars)
1451                 goto out;
1452         /* Don't need to search child DIE for external vars. */
1453         af->child = false;
1454         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1455
1456 out:
1457         if (strlist__empty(vl->vars)) {
1458                 strlist__delete(vl->vars);
1459                 vl->vars = NULL;
1460         }
1461
1462         return ret;
1463 }
1464
1465 /*
1466  * Find available variables at given probe point
1467  * Return the number of found probe points. Return 0 if there is no
1468  * matched probe point. Return <0 if an error occurs.
1469  */
1470 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1471                                       struct perf_probe_event *pev,
1472                                       struct variable_list **vls)
1473 {
1474         struct available_var_finder af = {
1475                         .pf = {.pev = pev, .callback = add_available_vars},
1476                         .mod = dbg->mod,
1477                         .max_vls = probe_conf.max_probes};
1478         int ret;
1479
1480         /* Allocate result vls array */
1481         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1482         if (*vls == NULL)
1483                 return -ENOMEM;
1484
1485         af.vls = *vls;
1486         af.nvls = 0;
1487
1488         ret = debuginfo__find_probes(dbg, &af.pf);
1489         if (ret < 0) {
1490                 /* Free vlist for error */
1491                 while (af.nvls--) {
1492                         zfree(&af.vls[af.nvls].point.symbol);
1493                         strlist__delete(af.vls[af.nvls].vars);
1494                 }
1495                 zfree(vls);
1496                 return ret;
1497         }
1498
1499         return (ret < 0) ? ret : af.nvls;
1500 }
1501
1502 /* For the kernel module, we need a special code to get a DIE */
1503 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1504                                 bool adjust_offset)
1505 {
1506         int n, i;
1507         Elf32_Word shndx;
1508         Elf_Scn *scn;
1509         Elf *elf;
1510         GElf_Shdr mem, *shdr;
1511         const char *p;
1512
1513         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1514         if (!elf)
1515                 return -EINVAL;
1516
1517         /* Get the number of relocations */
1518         n = dwfl_module_relocations(dbg->mod);
1519         if (n < 0)
1520                 return -ENOENT;
1521         /* Search the relocation related .text section */
1522         for (i = 0; i < n; i++) {
1523                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1524                 if (strcmp(p, ".text") == 0) {
1525                         /* OK, get the section header */
1526                         scn = elf_getscn(elf, shndx);
1527                         if (!scn)
1528                                 return -ENOENT;
1529                         shdr = gelf_getshdr(scn, &mem);
1530                         if (!shdr)
1531                                 return -ENOENT;
1532                         *offs = shdr->sh_addr;
1533                         if (adjust_offset)
1534                                 *offs -= shdr->sh_offset;
1535                 }
1536         }
1537         return 0;
1538 }
1539
1540 /* Reverse search */
1541 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1542                                 struct perf_probe_point *ppt)
1543 {
1544         Dwarf_Die cudie, spdie, indie;
1545         Dwarf_Addr _addr = 0, baseaddr = 0;
1546         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1547         int baseline = 0, lineno = 0, ret = 0;
1548
1549         /* We always need to relocate the address for aranges */
1550         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1551                 addr += baseaddr;
1552         /* Find cu die */
1553         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1554                 pr_warning("Failed to find debug information for address %lx\n",
1555                            addr);
1556                 ret = -EINVAL;
1557                 goto end;
1558         }
1559
1560         /* Find a corresponding line (filename and lineno) */
1561         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1562         /* Don't care whether it failed or not */
1563
1564         /* Find a corresponding function (name, baseline and baseaddr) */
1565         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1566                 /* Get function entry information */
1567                 func = basefunc = dwarf_diename(&spdie);
1568                 if (!func ||
1569                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1570                     dwarf_decl_line(&spdie, &baseline) != 0) {
1571                         lineno = 0;
1572                         goto post;
1573                 }
1574
1575                 fname = dwarf_decl_file(&spdie);
1576                 if (addr == (unsigned long)baseaddr) {
1577                         /* Function entry - Relative line number is 0 */
1578                         lineno = baseline;
1579                         goto post;
1580                 }
1581
1582                 /* Track down the inline functions step by step */
1583                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1584                                                 &indie)) {
1585                         /* There is an inline function */
1586                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1587                             _addr == addr) {
1588                                 /*
1589                                  * addr is at an inline function entry.
1590                                  * In this case, lineno should be the call-site
1591                                  * line number. (overwrite lineinfo)
1592                                  */
1593                                 lineno = die_get_call_lineno(&indie);
1594                                 fname = die_get_call_file(&indie);
1595                                 break;
1596                         } else {
1597                                 /*
1598                                  * addr is in an inline function body.
1599                                  * Since lineno points one of the lines
1600                                  * of the inline function, baseline should
1601                                  * be the entry line of the inline function.
1602                                  */
1603                                 tmp = dwarf_diename(&indie);
1604                                 if (!tmp ||
1605                                     dwarf_decl_line(&indie, &baseline) != 0)
1606                                         break;
1607                                 func = tmp;
1608                                 spdie = indie;
1609                         }
1610                 }
1611                 /* Verify the lineno and baseline are in a same file */
1612                 tmp = dwarf_decl_file(&spdie);
1613                 if (!tmp || strcmp(tmp, fname) != 0)
1614                         lineno = 0;
1615         }
1616
1617 post:
1618         /* Make a relative line number or an offset */
1619         if (lineno)
1620                 ppt->line = lineno - baseline;
1621         else if (basefunc) {
1622                 ppt->offset = addr - (unsigned long)baseaddr;
1623                 func = basefunc;
1624         }
1625
1626         /* Duplicate strings */
1627         if (func) {
1628                 ppt->function = strdup(func);
1629                 if (ppt->function == NULL) {
1630                         ret = -ENOMEM;
1631                         goto end;
1632                 }
1633         }
1634         if (fname) {
1635                 ppt->file = strdup(fname);
1636                 if (ppt->file == NULL) {
1637                         zfree(&ppt->function);
1638                         ret = -ENOMEM;
1639                         goto end;
1640                 }
1641         }
1642 end:
1643         if (ret == 0 && (fname || func))
1644                 ret = 1;        /* Found a point */
1645         return ret;
1646 }
1647
1648 /* Add a line and store the src path */
1649 static int line_range_add_line(const char *src, unsigned int lineno,
1650                                struct line_range *lr)
1651 {
1652         /* Copy source path */
1653         if (!lr->path) {
1654                 lr->path = strdup(src);
1655                 if (lr->path == NULL)
1656                         return -ENOMEM;
1657         }
1658         return intlist__add(lr->line_list, lineno);
1659 }
1660
1661 static int line_range_walk_cb(const char *fname, int lineno,
1662                               Dwarf_Addr addr __maybe_unused,
1663                               void *data)
1664 {
1665         struct line_finder *lf = data;
1666         int err;
1667
1668         if ((strtailcmp(fname, lf->fname) != 0) ||
1669             (lf->lno_s > lineno || lf->lno_e < lineno))
1670                 return 0;
1671
1672         err = line_range_add_line(fname, lineno, lf->lr);
1673         if (err < 0 && err != -EEXIST)
1674                 return err;
1675
1676         return 0;
1677 }
1678
1679 /* Find line range from its line number */
1680 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1681 {
1682         int ret;
1683
1684         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1685
1686         /* Update status */
1687         if (ret >= 0)
1688                 if (!intlist__empty(lf->lr->line_list))
1689                         ret = lf->found = 1;
1690                 else
1691                         ret = 0;        /* Lines are not found */
1692         else {
1693                 zfree(&lf->lr->path);
1694         }
1695         return ret;
1696 }
1697
1698 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1699 {
1700         int ret = find_line_range_by_line(in_die, data);
1701
1702         /*
1703          * We have to check all instances of inlined function, because
1704          * some execution paths can be optimized out depends on the
1705          * function argument of instances. However, if an error occurs,
1706          * it should be handled by the caller.
1707          */
1708         return ret < 0 ? ret : 0;
1709 }
1710
1711 /* Search function definition from function name */
1712 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1713 {
1714         struct dwarf_callback_param *param = data;
1715         struct line_finder *lf = param->data;
1716         struct line_range *lr = lf->lr;
1717
1718         /* Check declared file */
1719         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1720                 return DWARF_CB_OK;
1721
1722         if (die_is_func_def(sp_die) &&
1723             die_match_name(sp_die, lr->function)) {
1724                 lf->fname = dwarf_decl_file(sp_die);
1725                 dwarf_decl_line(sp_die, &lr->offset);
1726                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1727                 lf->lno_s = lr->offset + lr->start;
1728                 if (lf->lno_s < 0)      /* Overflow */
1729                         lf->lno_s = INT_MAX;
1730                 lf->lno_e = lr->offset + lr->end;
1731                 if (lf->lno_e < 0)      /* Overflow */
1732                         lf->lno_e = INT_MAX;
1733                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1734                 lr->start = lf->lno_s;
1735                 lr->end = lf->lno_e;
1736                 if (!die_is_func_instance(sp_die))
1737                         param->retval = die_walk_instances(sp_die,
1738                                                 line_range_inline_cb, lf);
1739                 else
1740                         param->retval = find_line_range_by_line(sp_die, lf);
1741                 return DWARF_CB_ABORT;
1742         }
1743         return DWARF_CB_OK;
1744 }
1745
1746 static int find_line_range_by_func(struct line_finder *lf)
1747 {
1748         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1749         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1750         return param.retval;
1751 }
1752
1753 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1754 {
1755         struct line_finder lf = {.lr = lr, .found = 0};
1756         int ret = 0;
1757         Dwarf_Off off = 0, noff;
1758         size_t cuhl;
1759         Dwarf_Die *diep;
1760         const char *comp_dir;
1761
1762         /* Fastpath: lookup by function name from .debug_pubnames section */
1763         if (lr->function) {
1764                 struct pubname_callback_param pubname_param = {
1765                         .function = lr->function, .file = lr->file,
1766                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1767                 struct dwarf_callback_param line_range_param = {
1768                         .data = (void *)&lf, .retval = 0};
1769
1770                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1771                                   &pubname_param, 0);
1772                 if (pubname_param.found) {
1773                         line_range_search_cb(&lf.sp_die, &line_range_param);
1774                         if (lf.found)
1775                                 goto found;
1776                 }
1777         }
1778
1779         /* Loop on CUs (Compilation Unit) */
1780         while (!lf.found && ret >= 0) {
1781                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1782                                  NULL, NULL, NULL) != 0)
1783                         break;
1784
1785                 /* Get the DIE(Debugging Information Entry) of this CU */
1786                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1787                 if (!diep)
1788                         continue;
1789
1790                 /* Check if target file is included. */
1791                 if (lr->file)
1792                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1793                 else
1794                         lf.fname = 0;
1795
1796                 if (!lr->file || lf.fname) {
1797                         if (lr->function)
1798                                 ret = find_line_range_by_func(&lf);
1799                         else {
1800                                 lf.lno_s = lr->start;
1801                                 lf.lno_e = lr->end;
1802                                 ret = find_line_range_by_line(NULL, &lf);
1803                         }
1804                 }
1805                 off = noff;
1806         }
1807
1808 found:
1809         /* Store comp_dir */
1810         if (lf.found) {
1811                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1812                 if (comp_dir) {
1813                         lr->comp_dir = strdup(comp_dir);
1814                         if (!lr->comp_dir)
1815                                 ret = -ENOMEM;
1816                 }
1817         }
1818
1819         pr_debug("path: %s\n", lr->path);
1820         return (ret < 0) ? ret : lf.found;
1821 }
1822
1823 /*
1824  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1825  * and chop off leading directories that do not exist. Result is passed back as
1826  * a newly allocated path on success.
1827  * Return 0 if file was found and readable, -errno otherwise.
1828  */
1829 int get_real_path(const char *raw_path, const char *comp_dir,
1830                          char **new_path)
1831 {
1832         const char *prefix = symbol_conf.source_prefix;
1833
1834         if (!prefix) {
1835                 if (raw_path[0] != '/' && comp_dir)
1836                         /* If not an absolute path, try to use comp_dir */
1837                         prefix = comp_dir;
1838                 else {
1839                         if (access(raw_path, R_OK) == 0) {
1840                                 *new_path = strdup(raw_path);
1841                                 return *new_path ? 0 : -ENOMEM;
1842                         } else
1843                                 return -errno;
1844                 }
1845         }
1846
1847         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1848         if (!*new_path)
1849                 return -ENOMEM;
1850
1851         for (;;) {
1852                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1853
1854                 if (access(*new_path, R_OK) == 0)
1855                         return 0;
1856
1857                 if (!symbol_conf.source_prefix) {
1858                         /* In case of searching comp_dir, don't retry */
1859                         zfree(new_path);
1860                         return -errno;
1861                 }
1862
1863                 switch (errno) {
1864                 case ENAMETOOLONG:
1865                 case ENOENT:
1866                 case EROFS:
1867                 case EFAULT:
1868                         raw_path = strchr(++raw_path, '/');
1869                         if (!raw_path) {
1870                                 zfree(new_path);
1871                                 return -ENOENT;
1872                         }
1873                         continue;
1874
1875                 default:
1876                         zfree(new_path);
1877                         return -errno;
1878                 }
1879         }
1880 }