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 /* Return innermost DIE */
 748 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
 749 {
 750         struct find_scope_param *fsp = data;
 751
 752         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 753         fsp->found = true;
 754         return 1;
 755 }
 756
 757 /* Find an appropriate scope fits to given conditions */
 758 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 759 {
 760         struct find_scope_param fsp = {
 761                 .function = pf->pev->point.function,
 762                 .file = pf->fname,
 763                 .line = pf->lno,
 764                 .diff = INT_MAX,
 765                 .die_mem = die_mem,
 766                 .found = false,
 767         };
 768         int ret;
 769
 770         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
 771                                    &fsp);
 772         if (!ret && !fsp.found)
 773                 cu_walk_functions_at(&pf->cu_die, pf->addr,
 774                                      find_inner_scope_cb, &fsp);
 775
 776         return fsp.found ? die_mem : NULL;
 777 }
 778
 779 static int probe_point_line_walker(const char *fname, int lineno,
 780                                    Dwarf_Addr addr, void *data)
 781 {
 782         struct probe_finder *pf = data;
 783         Dwarf_Die *sc_die, die_mem;
 784         int ret;
 785
 786         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 787                 return 0;
 788
 789         pf->addr = addr;
 790         sc_die = find_best_scope(pf, &die_mem);
 791         if (!sc_die) {
 792                 pr_warning("Failed to find scope of probe point.\n");
 793                 return -ENOENT;
 794         }
 795
 796         ret = call_probe_finder(sc_die, pf);
 797
 798         /* Continue if no error, because the line will be in inline function */
 799         return ret < 0 ? ret : 0;
 800 }
 801
 802 /* Find probe point from its line number */
 803 static int find_probe_point_by_line(struct probe_finder *pf)
 804 {
 805         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 806 }
 807
 808 /* Find lines which match lazy pattern */
 809 static int find_lazy_match_lines(struct intlist *list,
 810                                  const char *fname, const char *pat)
 811 {
 812         FILE *fp;
 813         char *line = NULL;
 814         size_t line_len;
 815         ssize_t len;
 816         int count = 0, linenum = 1;
 817         char sbuf[STRERR_BUFSIZE];
 818
 819         fp = fopen(fname, "r");
 820         if (!fp) {
 821                 pr_warning("Failed to open %s: %s\n", fname,
 822                            str_error_r(errno, sbuf, sizeof(sbuf)));
 823                 return -errno;
 824         }
 825
 826         while ((len = getline(&line, &line_len, fp)) > 0) {
 827
 828                 if (line[len - 1] == '\n')
 829                         line[len - 1] = '\0';
 830
 831                 if (strlazymatch(line, pat)) {
 832                         intlist__add(list, linenum);
 833                         count++;
 834                 }
 835                 linenum++;
 836         }
 837
 838         if (ferror(fp))
 839                 count = -errno;
 840         free(line);
 841         fclose(fp);
 842
 843         if (count == 0)
 844                 pr_debug("No matched lines found in %s.\n", fname);
 845         return count;
 846 }
 847
 848 static int probe_point_lazy_walker(const char *fname, int lineno,
 849                                    Dwarf_Addr addr, void *data)
 850 {
 851         struct probe_finder *pf = data;
 852         Dwarf_Die *sc_die, die_mem;
 853         int ret;
 854
 855         if (!intlist__has_entry(pf->lcache, lineno) ||
 856             strtailcmp(fname, pf->fname) != 0)
 857                 return 0;
 858
 859         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 860                  lineno, (unsigned long long)addr);
 861         pf->addr = addr;
 862         pf->lno = lineno;
 863         sc_die = find_best_scope(pf, &die_mem);
 864         if (!sc_die) {
 865                 pr_warning("Failed to find scope of probe point.\n");
 866                 return -ENOENT;
 867         }
 868
 869         ret = call_probe_finder(sc_die, pf);
 870
 871         /*
 872          * Continue if no error, because the lazy pattern will match
 873          * to other lines
 874          */
 875         return ret < 0 ? ret : 0;
 876 }
 877
 878 /* Find probe points from lazy pattern  */
 879 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 880 {
 881         int ret = 0;
 882         char *fpath;
 883
 884         if (intlist__empty(pf->lcache)) {
 885                 const char *comp_dir;
 886
 887                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 888                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 889                 if (ret < 0) {
 890                         pr_warning("Failed to find source file path.\n");
 891                         return ret;
 892                 }
 893
 894                 /* Matching lazy line pattern */
 895                 ret = find_lazy_match_lines(pf->lcache, fpath,
 896                                             pf->pev->point.lazy_line);
 897                 free(fpath);
 898                 if (ret <= 0)
 899                         return ret;
 900         }
 901
 902         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 903 }
 904
 905 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 906 {
 907         struct perf_probe_point *pp = &pf->pev->point;
 908
 909         /* Not uprobe? */
 910         if (!pf->pev->uprobes)
 911                 return;
 912
 913         /* Compiled with optimization? */
 914         if (die_is_optimized_target(&pf->cu_die))
 915                 return;
 916
 917         /* Don't know entrypc? */
 918         if (!pf->addr)
 919                 return;
 920
 921         /* Only FUNC and FUNC@SRC are eligible. */
 922         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 923             pp->offset || pp->abs_address)
 924                 return;
 925
 926         /* Not interested in func parameter? */
 927         if (!perf_probe_with_var(pf->pev))
 928                 return;
 929
 930         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 931                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 932                 pf->addr);
 933
 934         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 935 }
 936
 937 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 938 {
 939         struct probe_finder *pf = data;
 940         struct perf_probe_point *pp = &pf->pev->point;
 941         Dwarf_Addr addr;
 942         int ret;
 943
 944         if (pp->lazy_line)
 945                 ret = find_probe_point_lazy(in_die, pf);
 946         else {
 947                 /* Get probe address */
 948                 if (die_entrypc(in_die, &addr) != 0) {
 949                         pr_warning("Failed to get entry address of %s.\n",
 950                                    dwarf_diename(in_die));
 951                         return -ENOENT;
 952                 }
 953                 if (addr == 0) {
 954                         pr_debug("%s has no valid entry address. skipped.\n",
 955                                  dwarf_diename(in_die));
 956                         return -ENOENT;
 957                 }
 958                 pf->addr = addr;
 959                 pf->addr += pp->offset;
 960                 pr_debug("found inline addr: 0x%jx\n",
 961                          (uintmax_t)pf->addr);
 962
 963                 ret = call_probe_finder(in_die, pf);
 964         }
 965
 966         return ret;
 967 }
 968
 969 /* Callback parameter with return value for libdw */
 970 struct dwarf_callback_param {
 971         void *data;
 972         int retval;
 973 };
 974
 975 /* Search function from function name */
 976 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 977 {
 978         struct dwarf_callback_param *param = data;
 979         struct probe_finder *pf = param->data;
 980         struct perf_probe_point *pp = &pf->pev->point;
 981
 982         /* Check tag and diename */
 983         if (!die_is_func_def(sp_die) ||
 984             !die_match_name(sp_die, pp->function))
 985                 return DWARF_CB_OK;
 986
 987         /* Check declared file */
 988         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 989                 return DWARF_CB_OK;
 990
 991         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
 992                  (unsigned long)dwarf_dieoffset(sp_die));
 993         pf->fname = dwarf_decl_file(sp_die);
 994         if (pp->line) { /* Function relative line */
 995                 dwarf_decl_line(sp_die, &pf->lno);
 996                 pf->lno += pp->line;
 997                 param->retval = find_probe_point_by_line(pf);
 998         } else if (die_is_func_instance(sp_die)) {
 999                 /* Instances always have the entry address */
1000                 die_entrypc(sp_die, &pf->addr);
1001                 /* But in some case the entry address is 0 */
1002                 if (pf->addr == 0) {
1003                         pr_debug("%s has no entry PC. Skipped\n",
1004                                  dwarf_diename(sp_die));
1005                         param->retval = 0;
1006                 /* Real function */
1007                 } else if (pp->lazy_line)
1008                         param->retval = find_probe_point_lazy(sp_die, pf);
1009                 else {
1010                         skip_prologue(sp_die, pf);
1011                         pf->addr += pp->offset;
1012                         /* TODO: Check the address in this function */
1013                         param->retval = call_probe_finder(sp_die, pf);
1014                 }
1015         } else if (!probe_conf.no_inlines) {
1016                 /* Inlined function: search instances */
1017                 param->retval = die_walk_instances(sp_die,
1018                                         probe_point_inline_cb, (void *)pf);
1019                 /* This could be a non-existed inline definition */
1020                 if (param->retval == -ENOENT)
1021                         param->retval = 0;
1022         }
1023
1024         /* We need to find other candidates */
1025         if (strisglob(pp->function) && param->retval >= 0) {
1026                 param->retval = 0;      /* We have to clear the result */
1027                 return DWARF_CB_OK;
1028         }
1029
1030         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1031 }
1032
1033 static int find_probe_point_by_func(struct probe_finder *pf)
1034 {
1035         struct dwarf_callback_param _param = {.data = (void *)pf,
1036                                               .retval = 0};
1037         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1038         return _param.retval;
1039 }
1040
1041 struct pubname_callback_param {
1042         char *function;
1043         char *file;
1044         Dwarf_Die *cu_die;
1045         Dwarf_Die *sp_die;
1046         int found;
1047 };
1048
1049 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1050 {
1051         struct pubname_callback_param *param = data;
1052
1053         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1054                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1055                         return DWARF_CB_OK;
1056
1057                 if (die_match_name(param->sp_die, param->function)) {
1058                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1059                                 return DWARF_CB_OK;
1060
1061                         if (param->file &&
1062                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1063                                 return DWARF_CB_OK;
1064
1065                         param->found = 1;
1066                         return DWARF_CB_ABORT;
1067                 }
1068         }
1069
1070         return DWARF_CB_OK;
1071 }
1072
1073 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1074                                   struct probe_finder *pf)
1075 {
1076         struct perf_probe_point *pp = &pf->pev->point;
1077         Dwarf_Off off, noff;
1078         size_t cuhl;
1079         Dwarf_Die *diep;
1080         int ret = 0;
1081
1082         off = 0;
1083         pf->lcache = intlist__new(NULL);
1084         if (!pf->lcache)
1085                 return -ENOMEM;
1086
1087         /* Fastpath: lookup by function name from .debug_pubnames section */
1088         if (pp->function && !strisglob(pp->function)) {
1089                 struct pubname_callback_param pubname_param = {
1090                         .function = pp->function,
1091                         .file     = pp->file,
1092                         .cu_die   = &pf->cu_die,
1093                         .sp_die   = &pf->sp_die,
1094                         .found    = 0,
1095                 };
1096                 struct dwarf_callback_param probe_param = {
1097                         .data = pf,
1098                 };
1099
1100                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1101                                   &pubname_param, 0);
1102                 if (pubname_param.found) {
1103                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1104                         if (ret)
1105                                 goto found;
1106                 }
1107         }
1108
1109         /* Loop on CUs (Compilation Unit) */
1110         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1111                 /* Get the DIE(Debugging Information Entry) of this CU */
1112                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1113                 if (!diep)
1114                         continue;
1115
1116                 /* Check if target file is included. */
1117                 if (pp->file)
1118                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1119                 else
1120                         pf->fname = NULL;
1121
1122                 if (!pp->file || pf->fname) {
1123                         if (pp->function)
1124                                 ret = find_probe_point_by_func(pf);
1125                         else if (pp->lazy_line)
1126                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1127                         else {
1128                                 pf->lno = pp->line;
1129                                 ret = find_probe_point_by_line(pf);
1130                         }
1131                         if (ret < 0)
1132                                 break;
1133                 }
1134                 off = noff;
1135         }
1136
1137 found:
1138         intlist__delete(pf->lcache);
1139         pf->lcache = NULL;
1140
1141         return ret;
1142 }
1143
1144 /* Find probe points from debuginfo */
1145 static int debuginfo__find_probes(struct debuginfo *dbg,
1146                                   struct probe_finder *pf)
1147 {
1148         int ret = 0;
1149         Elf *elf;
1150         GElf_Ehdr ehdr;
1151
1152         if (pf->cfi_eh || pf->cfi_dbg)
1153                 return debuginfo__find_probe_location(dbg, pf);
1154
1155         /* Get the call frame information from this dwarf */
1156         elf = dwarf_getelf(dbg->dbg);
1157         if (elf == NULL)
1158                 return -EINVAL;
1159
1160         if (gelf_getehdr(elf, &ehdr) == NULL)
1161                 return -EINVAL;
1162
1163         pf->machine = ehdr.e_machine;
1164
1165 #if _ELFUTILS_PREREQ(0, 142)
1166         do {
1167                 GElf_Shdr shdr;
1168
1169                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1170                     shdr.sh_type == SHT_PROGBITS)
1171                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1172
1173                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1174         } while (0);
1175 #endif
1176
1177         ret = debuginfo__find_probe_location(dbg, pf);
1178         return ret;
1179 }
1180
1181 struct local_vars_finder {
1182         struct probe_finder *pf;
1183         struct perf_probe_arg *args;
1184         bool vars;
1185         int max_args;
1186         int nargs;
1187         int ret;
1188 };
1189
1190 /* Collect available variables in this scope */
1191 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1192 {
1193         struct local_vars_finder *vf = data;
1194         struct probe_finder *pf = vf->pf;
1195         int tag;
1196
1197         tag = dwarf_tag(die_mem);
1198         if (tag == DW_TAG_formal_parameter ||
1199             (tag == DW_TAG_variable && vf->vars)) {
1200                 if (convert_variable_location(die_mem, vf->pf->addr,
1201                                               vf->pf->fb_ops, &pf->sp_die,
1202                                               pf->machine, NULL) == 0) {
1203                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1204                         if (vf->args[vf->nargs].var == NULL) {
1205                                 vf->ret = -ENOMEM;
1206                                 return DIE_FIND_CB_END;
1207                         }
1208                         pr_debug(" %s", vf->args[vf->nargs].var);
1209                         vf->nargs++;
1210                 }
1211         }
1212
1213         if (dwarf_haspc(die_mem, vf->pf->addr))
1214                 return DIE_FIND_CB_CONTINUE;
1215         else
1216                 return DIE_FIND_CB_SIBLING;
1217 }
1218
1219 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1220                              struct perf_probe_arg *args)
1221 {
1222         Dwarf_Die die_mem;
1223         int i;
1224         int n = 0;
1225         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1226                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1227
1228         for (i = 0; i < pf->pev->nargs; i++) {
1229                 /* var never be NULL */
1230                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1231                         vf.vars = true;
1232                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1233                         /* Copy normal argument */
1234                         args[n] = pf->pev->args[i];
1235                         n++;
1236                         continue;
1237                 }
1238                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1239                 vf.nargs = n;
1240                 /* Special local variables */
1241                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1242                                &die_mem);
1243                 pr_debug(" (%d)\n", vf.nargs - n);
1244                 if (vf.ret < 0)
1245                         return vf.ret;
1246                 n = vf.nargs;
1247         }
1248         return n;
1249 }
1250
1251 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1252 {
1253         int i;
1254
1255         for (i = 0; i < tf->ntevs; i++) {
1256                 if (tf->pf.addr == tf->tevs[i].point.address)
1257                         return true;
1258         }
1259         return false;
1260 }
1261
1262 /* Add a found probe point into trace event list */
1263 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1264 {
1265         struct trace_event_finder *tf =
1266                         container_of(pf, struct trace_event_finder, pf);
1267         struct perf_probe_point *pp = &pf->pev->point;
1268         struct probe_trace_event *tev;
1269         struct perf_probe_arg *args = NULL;
1270         int ret, i;
1271
1272         /*
1273          * For some reason (e.g. different column assigned to same address)
1274          * This callback can be called with the address which already passed.
1275          * Ignore it first.
1276          */
1277         if (trace_event_finder_overlap(tf))
1278                 return 0;
1279
1280         /* Check number of tevs */
1281         if (tf->ntevs == tf->max_tevs) {
1282                 pr_warning("Too many( > %d) probe point found.\n",
1283                            tf->max_tevs);
1284                 return -ERANGE;
1285         }
1286         tev = &tf->tevs[tf->ntevs++];
1287
1288         /* Trace point should be converted from subprogram DIE */
1289         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1290                                      pp->retprobe, pp->function, &tev->point);
1291         if (ret < 0)
1292                 goto end;
1293
1294         tev->point.realname = strdup(dwarf_diename(sc_die));
1295         if (!tev->point.realname) {
1296                 ret = -ENOMEM;
1297                 goto end;
1298         }
1299
1300         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1301                  tev->point.offset);
1302
1303         /* Expand special probe argument if exist */
1304         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1305         if (args == NULL) {
1306                 ret = -ENOMEM;
1307                 goto end;
1308         }
1309
1310         ret = expand_probe_args(sc_die, pf, args);
1311         if (ret < 0)
1312                 goto end;
1313
1314         tev->nargs = ret;
1315         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1316         if (tev->args == NULL) {
1317                 ret = -ENOMEM;
1318                 goto end;
1319         }
1320
1321         /* Find each argument */
1322         for (i = 0; i < tev->nargs; i++) {
1323                 pf->pvar = &args[i];
1324                 pf->tvar = &tev->args[i];
1325                 /* Variable should be found from scope DIE */
1326                 ret = find_variable(sc_die, pf);
1327                 if (ret != 0)
1328                         break;
1329         }
1330
1331 end:
1332         if (ret) {
1333                 clear_probe_trace_event(tev);
1334                 tf->ntevs--;
1335         }
1336         free(args);
1337         return ret;
1338 }
1339
1340 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1341 int debuginfo__find_trace_events(struct debuginfo *dbg,
1342                                  struct perf_probe_event *pev,
1343                                  struct probe_trace_event **tevs)
1344 {
1345         struct trace_event_finder tf = {
1346                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1347                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1348         int ret, i;
1349
1350         /* Allocate result tevs array */
1351         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1352         if (*tevs == NULL)
1353                 return -ENOMEM;
1354
1355         tf.tevs = *tevs;
1356         tf.ntevs = 0;
1357
1358         ret = debuginfo__find_probes(dbg, &tf.pf);
1359         if (ret < 0) {
1360                 for (i = 0; i < tf.ntevs; i++)
1361                         clear_probe_trace_event(&tf.tevs[i]);
1362                 zfree(tevs);
1363                 return ret;
1364         }
1365
1366         return (ret < 0) ? ret : tf.ntevs;
1367 }
1368
1369 /* Collect available variables in this scope */
1370 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1371 {
1372         struct available_var_finder *af = data;
1373         struct variable_list *vl;
1374         struct strbuf buf = STRBUF_INIT;
1375         int tag, ret;
1376
1377         vl = &af->vls[af->nvls - 1];
1378
1379         tag = dwarf_tag(die_mem);
1380         if (tag == DW_TAG_formal_parameter ||
1381             tag == DW_TAG_variable) {
1382                 ret = convert_variable_location(die_mem, af->pf.addr,
1383                                                 af->pf.fb_ops, &af->pf.sp_die,
1384                                                 af->pf.machine, NULL);
1385                 if (ret == 0 || ret == -ERANGE) {
1386                         int ret2;
1387                         bool externs = !af->child;
1388
1389                         if (strbuf_init(&buf, 64) < 0)
1390                                 goto error;
1391
1392                         if (probe_conf.show_location_range) {
1393                                 if (!externs)
1394                                         ret2 = strbuf_add(&buf,
1395                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1396                                 else
1397                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1398                                 if (ret2)
1399                                         goto error;
1400                         }
1401
1402                         ret2 = die_get_varname(die_mem, &buf);
1403
1404                         if (!ret2 && probe_conf.show_location_range &&
1405                                 !externs) {
1406                                 if (strbuf_addch(&buf, '\t') < 0)
1407                                         goto error;
1408                                 ret2 = die_get_var_range(&af->pf.sp_die,
1409                                                         die_mem, &buf);
1410                         }
1411
1412                         pr_debug("Add new var: %s\n", buf.buf);
1413                         if (ret2 == 0) {
1414                                 strlist__add(vl->vars,
1415                                         strbuf_detach(&buf, NULL));
1416                         }
1417                         strbuf_release(&buf);
1418                 }
1419         }
1420
1421         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1422                 return DIE_FIND_CB_CONTINUE;
1423         else
1424                 return DIE_FIND_CB_SIBLING;
1425 error:
1426         strbuf_release(&buf);
1427         pr_debug("Error in strbuf\n");
1428         return DIE_FIND_CB_END;
1429 }
1430
1431 /* Add a found vars into available variables list */
1432 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1433 {
1434         struct available_var_finder *af =
1435                         container_of(pf, struct available_var_finder, pf);
1436         struct perf_probe_point *pp = &pf->pev->point;
1437         struct variable_list *vl;
1438         Dwarf_Die die_mem;
1439         int ret;
1440
1441         /* Check number of tevs */
1442         if (af->nvls == af->max_vls) {
1443                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1444                 return -ERANGE;
1445         }
1446         vl = &af->vls[af->nvls++];
1447
1448         /* Trace point should be converted from subprogram DIE */
1449         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1450                                      pp->retprobe, pp->function, &vl->point);
1451         if (ret < 0)
1452                 return ret;
1453
1454         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1455                  vl->point.offset);
1456
1457         /* Find local variables */
1458         vl->vars = strlist__new(NULL, NULL);
1459         if (vl->vars == NULL)
1460                 return -ENOMEM;
1461         af->child = true;
1462         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1463
1464         /* Find external variables */
1465         if (!probe_conf.show_ext_vars)
1466                 goto out;
1467         /* Don't need to search child DIE for external vars. */
1468         af->child = false;
1469         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1470
1471 out:
1472         if (strlist__empty(vl->vars)) {
1473                 strlist__delete(vl->vars);
1474                 vl->vars = NULL;
1475         }
1476
1477         return ret;
1478 }
1479
1480 /*
1481  * Find available variables at given probe point
1482  * Return the number of found probe points. Return 0 if there is no
1483  * matched probe point. Return <0 if an error occurs.
1484  */
1485 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1486                                       struct perf_probe_event *pev,
1487                                       struct variable_list **vls)
1488 {
1489         struct available_var_finder af = {
1490                         .pf = {.pev = pev, .callback = add_available_vars},
1491                         .mod = dbg->mod,
1492                         .max_vls = probe_conf.max_probes};
1493         int ret;
1494
1495         /* Allocate result vls array */
1496         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1497         if (*vls == NULL)
1498                 return -ENOMEM;
1499
1500         af.vls = *vls;
1501         af.nvls = 0;
1502
1503         ret = debuginfo__find_probes(dbg, &af.pf);
1504         if (ret < 0) {
1505                 /* Free vlist for error */
1506                 while (af.nvls--) {
1507                         zfree(&af.vls[af.nvls].point.symbol);
1508                         strlist__delete(af.vls[af.nvls].vars);
1509                 }
1510                 zfree(vls);
1511                 return ret;
1512         }
1513
1514         return (ret < 0) ? ret : af.nvls;
1515 }
1516
1517 /* For the kernel module, we need a special code to get a DIE */
1518 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1519                                 bool adjust_offset)
1520 {
1521         int n, i;
1522         Elf32_Word shndx;
1523         Elf_Scn *scn;
1524         Elf *elf;
1525         GElf_Shdr mem, *shdr;
1526         const char *p;
1527
1528         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1529         if (!elf)
1530                 return -EINVAL;
1531
1532         /* Get the number of relocations */
1533         n = dwfl_module_relocations(dbg->mod);
1534         if (n < 0)
1535                 return -ENOENT;
1536         /* Search the relocation related .text section */
1537         for (i = 0; i < n; i++) {
1538                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1539                 if (strcmp(p, ".text") == 0) {
1540                         /* OK, get the section header */
1541                         scn = elf_getscn(elf, shndx);
1542                         if (!scn)
1543                                 return -ENOENT;
1544                         shdr = gelf_getshdr(scn, &mem);
1545                         if (!shdr)
1546                                 return -ENOENT;
1547                         *offs = shdr->sh_addr;
1548                         if (adjust_offset)
1549                                 *offs -= shdr->sh_offset;
1550                 }
1551         }
1552         return 0;
1553 }
1554
1555 /* Reverse search */
1556 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1557                                 struct perf_probe_point *ppt)
1558 {
1559         Dwarf_Die cudie, spdie, indie;
1560         Dwarf_Addr _addr = 0, baseaddr = 0;
1561         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1562         int baseline = 0, lineno = 0, ret = 0;
1563
1564         /* We always need to relocate the address for aranges */
1565         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1566                 addr += baseaddr;
1567         /* Find cu die */
1568         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1569                 pr_warning("Failed to find debug information for address %lx\n",
1570                            addr);
1571                 ret = -EINVAL;
1572                 goto end;
1573         }
1574
1575         /* Find a corresponding line (filename and lineno) */
1576         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1577         /* Don't care whether it failed or not */
1578
1579         /* Find a corresponding function (name, baseline and baseaddr) */
1580         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1581                 /* Get function entry information */
1582                 func = basefunc = dwarf_diename(&spdie);
1583                 if (!func ||
1584                     die_entrypc(&spdie, &baseaddr) != 0 ||
1585                     dwarf_decl_line(&spdie, &baseline) != 0) {
1586                         lineno = 0;
1587                         goto post;
1588                 }
1589
1590                 fname = dwarf_decl_file(&spdie);
1591                 if (addr == (unsigned long)baseaddr) {
1592                         /* Function entry - Relative line number is 0 */
1593                         lineno = baseline;
1594                         goto post;
1595                 }
1596
1597                 /* Track down the inline functions step by step */
1598                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1599                                                 &indie)) {
1600                         /* There is an inline function */
1601                         if (die_entrypc(&indie, &_addr) == 0 &&
1602                             _addr == addr) {
1603                                 /*
1604                                  * addr is at an inline function entry.
1605                                  * In this case, lineno should be the call-site
1606                                  * line number. (overwrite lineinfo)
1607                                  */
1608                                 lineno = die_get_call_lineno(&indie);
1609                                 fname = die_get_call_file(&indie);
1610                                 break;
1611                         } else {
1612                                 /*
1613                                  * addr is in an inline function body.
1614                                  * Since lineno points one of the lines
1615                                  * of the inline function, baseline should
1616                                  * be the entry line of the inline function.
1617                                  */
1618                                 tmp = dwarf_diename(&indie);
1619                                 if (!tmp ||
1620                                     dwarf_decl_line(&indie, &baseline) != 0)
1621                                         break;
1622                                 func = tmp;
1623                                 spdie = indie;
1624                         }
1625                 }
1626                 /* Verify the lineno and baseline are in a same file */
1627                 tmp = dwarf_decl_file(&spdie);
1628                 if (!tmp || strcmp(tmp, fname) != 0)
1629                         lineno = 0;
1630         }
1631
1632 post:
1633         /* Make a relative line number or an offset */
1634         if (lineno)
1635                 ppt->line = lineno - baseline;
1636         else if (basefunc) {
1637                 ppt->offset = addr - (unsigned long)baseaddr;
1638                 func = basefunc;
1639         }
1640
1641         /* Duplicate strings */
1642         if (func) {
1643                 ppt->function = strdup(func);
1644                 if (ppt->function == NULL) {
1645                         ret = -ENOMEM;
1646                         goto end;
1647                 }
1648         }
1649         if (fname) {
1650                 ppt->file = strdup(fname);
1651                 if (ppt->file == NULL) {
1652                         zfree(&ppt->function);
1653                         ret = -ENOMEM;
1654                         goto end;
1655                 }
1656         }
1657 end:
1658         if (ret == 0 && (fname || func))
1659                 ret = 1;        /* Found a point */
1660         return ret;
1661 }
1662
1663 /* Add a line and store the src path */
1664 static int line_range_add_line(const char *src, unsigned int lineno,
1665                                struct line_range *lr)
1666 {
1667         /* Copy source path */
1668         if (!lr->path) {
1669                 lr->path = strdup(src);
1670                 if (lr->path == NULL)
1671                         return -ENOMEM;
1672         }
1673         return intlist__add(lr->line_list, lineno);
1674 }
1675
1676 static int line_range_walk_cb(const char *fname, int lineno,
1677                               Dwarf_Addr addr __maybe_unused,
1678                               void *data)
1679 {
1680         struct line_finder *lf = data;
1681         int err;
1682
1683         if ((strtailcmp(fname, lf->fname) != 0) ||
1684             (lf->lno_s > lineno || lf->lno_e < lineno))
1685                 return 0;
1686
1687         err = line_range_add_line(fname, lineno, lf->lr);
1688         if (err < 0 && err != -EEXIST)
1689                 return err;
1690
1691         return 0;
1692 }
1693
1694 /* Find line range from its line number */
1695 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1696 {
1697         int ret;
1698
1699         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1700
1701         /* Update status */
1702         if (ret >= 0)
1703                 if (!intlist__empty(lf->lr->line_list))
1704                         ret = lf->found = 1;
1705                 else
1706                         ret = 0;        /* Lines are not found */
1707         else {
1708                 zfree(&lf->lr->path);
1709         }
1710         return ret;
1711 }
1712
1713 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1714 {
1715         int ret = find_line_range_by_line(in_die, data);
1716
1717         /*
1718          * We have to check all instances of inlined function, because
1719          * some execution paths can be optimized out depends on the
1720          * function argument of instances. However, if an error occurs,
1721          * it should be handled by the caller.
1722          */
1723         return ret < 0 ? ret : 0;
1724 }
1725
1726 /* Search function definition from function name */
1727 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1728 {
1729         struct dwarf_callback_param *param = data;
1730         struct line_finder *lf = param->data;
1731         struct line_range *lr = lf->lr;
1732
1733         /* Check declared file */
1734         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1735                 return DWARF_CB_OK;
1736
1737         if (die_is_func_def(sp_die) &&
1738             die_match_name(sp_die, lr->function)) {
1739                 lf->fname = dwarf_decl_file(sp_die);
1740                 dwarf_decl_line(sp_die, &lr->offset);
1741                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1742                 lf->lno_s = lr->offset + lr->start;
1743                 if (lf->lno_s < 0)      /* Overflow */
1744                         lf->lno_s = INT_MAX;
1745                 lf->lno_e = lr->offset + lr->end;
1746                 if (lf->lno_e < 0)      /* Overflow */
1747                         lf->lno_e = INT_MAX;
1748                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1749                 lr->start = lf->lno_s;
1750                 lr->end = lf->lno_e;
1751                 if (!die_is_func_instance(sp_die))
1752                         param->retval = die_walk_instances(sp_die,
1753                                                 line_range_inline_cb, lf);
1754                 else
1755                         param->retval = find_line_range_by_line(sp_die, lf);
1756                 return DWARF_CB_ABORT;
1757         }
1758         return DWARF_CB_OK;
1759 }
1760
1761 static int find_line_range_by_func(struct line_finder *lf)
1762 {
1763         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1764         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1765         return param.retval;
1766 }
1767
1768 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1769 {
1770         struct line_finder lf = {.lr = lr, .found = 0};
1771         int ret = 0;
1772         Dwarf_Off off = 0, noff;
1773         size_t cuhl;
1774         Dwarf_Die *diep;
1775         const char *comp_dir;
1776
1777         /* Fastpath: lookup by function name from .debug_pubnames section */
1778         if (lr->function) {
1779                 struct pubname_callback_param pubname_param = {
1780                         .function = lr->function, .file = lr->file,
1781                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1782                 struct dwarf_callback_param line_range_param = {
1783                         .data = (void *)&lf, .retval = 0};
1784
1785                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1786                                   &pubname_param, 0);
1787                 if (pubname_param.found) {
1788                         line_range_search_cb(&lf.sp_die, &line_range_param);
1789                         if (lf.found)
1790                                 goto found;
1791                 }
1792         }
1793
1794         /* Loop on CUs (Compilation Unit) */
1795         while (!lf.found && ret >= 0) {
1796                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1797                                  NULL, NULL, NULL) != 0)
1798                         break;
1799
1800                 /* Get the DIE(Debugging Information Entry) of this CU */
1801                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1802                 if (!diep)
1803                         continue;
1804
1805                 /* Check if target file is included. */
1806                 if (lr->file)
1807                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1808                 else
1809                         lf.fname = 0;
1810
1811                 if (!lr->file || lf.fname) {
1812                         if (lr->function)
1813                                 ret = find_line_range_by_func(&lf);
1814                         else {
1815                                 lf.lno_s = lr->start;
1816                                 lf.lno_e = lr->end;
1817                                 ret = find_line_range_by_line(NULL, &lf);
1818                         }
1819                 }
1820                 off = noff;
1821         }
1822
1823 found:
1824         /* Store comp_dir */
1825         if (lf.found) {
1826                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1827                 if (comp_dir) {
1828                         lr->comp_dir = strdup(comp_dir);
1829                         if (!lr->comp_dir)
1830                                 ret = -ENOMEM;
1831                 }
1832         }
1833
1834         pr_debug("path: %s\n", lr->path);
1835         return (ret < 0) ? ret : lf.found;
1836 }
1837
1838 /*
1839  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1840  * and chop off leading directories that do not exist. Result is passed back as
1841  * a newly allocated path on success.
1842  * Return 0 if file was found and readable, -errno otherwise.
1843  */
1844 int get_real_path(const char *raw_path, const char *comp_dir,
1845                          char **new_path)
1846 {
1847         const char *prefix = symbol_conf.source_prefix;
1848
1849         if (!prefix) {
1850                 if (raw_path[0] != '/' && comp_dir)
1851                         /* If not an absolute path, try to use comp_dir */
1852                         prefix = comp_dir;
1853                 else {
1854                         if (access(raw_path, R_OK) == 0) {
1855                                 *new_path = strdup(raw_path);
1856                                 return *new_path ? 0 : -ENOMEM;
1857                         } else
1858                                 return -errno;
1859                 }
1860         }
1861
1862         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1863         if (!*new_path)
1864                 return -ENOMEM;
1865
1866         for (;;) {
1867                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1868
1869                 if (access(*new_path, R_OK) == 0)
1870                         return 0;
1871
1872                 if (!symbol_conf.source_prefix) {
1873                         /* In case of searching comp_dir, don't retry */
1874                         zfree(new_path);
1875                         return -errno;
1876                 }
1877
1878                 switch (errno) {
1879                 case ENAMETOOLONG:
1880                 case ENOENT:
1881                 case EROFS:
1882                 case EFAULT:
1883                         raw_path = strchr(++raw_path, '/');
1884                         if (!raw_path) {
1885                                 zfree(new_path);
1886                                 return -ENOENT;
1887                         }
1888                         continue;
1889
1890                 default:
1891                         zfree(new_path);
1892                         return -errno;
1893                 }
1894         }
1895 }