tools/perf/util/probe-finder.c

   1 /*
   2  * probe-finder.c : C expression to kprobe event converter
   3  *
   4  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  */
  21
  22 #include <sys/utsname.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <unistd.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <stdarg.h>
  32 #include <dwarf-regs.h>
  33
  34 #include <linux/bitops.h>
  35 #include "event.h"
  36 #include "dso.h"
  37 #include "debug.h"
  38 #include "intlist.h"
  39 #include "util.h"
  40 #include "symbol.h"
  41 #include "probe-finder.h"
  42
  43 /* Kprobe tracer basic type is up to u64 */
  44 #define MAX_BASIC_TYPE_BITS     64
  45
  46 /* Dwarf FL wrappers */
  47 static char *debuginfo_path;    /* Currently dummy */
  48
  49 static const Dwfl_Callbacks offline_callbacks = {
  50         .find_debuginfo = dwfl_standard_find_debuginfo,
  51         .debuginfo_path = &debuginfo_path,
  52
  53         .section_address = dwfl_offline_section_address,
  54
  55         /* We use this table for core files too.  */
  56         .find_elf = dwfl_build_id_find_elf,
  57 };
  58
  59 /* Get a Dwarf from offline image */
  60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  61                                          const char *path)
  62 {
  63         int fd;
  64
  65         fd = open(path, O_RDONLY);
  66         if (fd < 0)
  67                 return fd;
  68
  69         dbg->dwfl = dwfl_begin(&offline_callbacks);
  70         if (!dbg->dwfl)
  71                 goto error;
  72
  73         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  74         if (!dbg->mod)
  75                 goto error;
  76
  77         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  78         if (!dbg->dbg)
  79                 goto error;
  80
  81         return 0;
  82 error:
  83         if (dbg->dwfl)
  84                 dwfl_end(dbg->dwfl);
  85         else
  86                 close(fd);
  87         memset(dbg, 0, sizeof(*dbg));
  88
  89         return -ENOENT;
  90 }
  91
  92 static struct debuginfo *__debuginfo__new(const char *path)
  93 {
  94         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  95         if (!dbg)
  96                 return NULL;
  97
  98         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  99                 zfree(&dbg);
 100         if (dbg)
 101                 pr_debug("Open Debuginfo file: %s\n", path);
 102         return dbg;
 103 }
 104
 105 enum dso_binary_type distro_dwarf_types[] = {
 106         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 107         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 108         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 109         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 110         DSO_BINARY_TYPE__NOT_FOUND,
 111 };
 112
 113 struct debuginfo *debuginfo__new(const char *path)
 114 {
 115         enum dso_binary_type *type;
 116         char buf[PATH_MAX], nil = '\0';
 117         struct dso *dso;
 118         struct debuginfo *dinfo = NULL;
 119
 120         /* Try to open distro debuginfo files */
 121         dso = dso__new(path);
 122         if (!dso)
 123                 goto out;
 124
 125         for (type = distro_dwarf_types;
 126              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 127              type++) {
 128                 if (dso__read_binary_type_filename(dso, *type, &nil,
 129                                                    buf, PATH_MAX) < 0)
 130                         continue;
 131                 dinfo = __debuginfo__new(buf);
 132         }
 133         dso__delete(dso);
 134
 135 out:
 136         /* if failed to open all distro debuginfo, open given binary */
 137         return dinfo ? : __debuginfo__new(path);
 138 }
 139
 140 void debuginfo__delete(struct debuginfo *dbg)
 141 {
 142         if (dbg) {
 143                 if (dbg->dwfl)
 144                         dwfl_end(dbg->dwfl);
 145                 free(dbg);
 146         }
 147 }
 148
 149 /*
 150  * Probe finder related functions
 151  */
 152
 153 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 154 {
 155         struct probe_trace_arg_ref *ref;
 156         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 157         if (ref != NULL)
 158                 ref->offset = offs;
 159         return ref;
 160 }
 161
 162 /*
 163  * Convert a location into trace_arg.
 164  * If tvar == NULL, this just checks variable can be converted.
 165  * If fentry == true and vr_die is a parameter, do huristic search
 166  * for the location fuzzed by function entry mcount.
 167  */
 168 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 169                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 170                                      struct probe_trace_arg *tvar)
 171 {
 172         Dwarf_Attribute attr;
 173         Dwarf_Addr tmp = 0;
 174         Dwarf_Op *op;
 175         size_t nops;
 176         unsigned int regn;
 177         Dwarf_Word offs = 0;
 178         bool ref = false;
 179         const char *regs;
 180         int ret;
 181
 182         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 183                 goto static_var;
 184
 185         /* TODO: handle more than 1 exprs */
 186         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 187                 return -EINVAL; /* Broken DIE ? */
 188         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 189                 ret = dwarf_entrypc(sp_die, &tmp);
 190                 if (ret || addr != tmp ||
 191                     dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
 192                     dwarf_highpc(sp_die, &tmp))
 193                         return -ENOENT;
 194                 /*
 195                  * This is fuzzed by fentry mcount. We try to find the
 196                  * parameter location at the earliest address.
 197                  */
 198                 for (addr += 1; addr <= tmp; addr++) {
 199                         if (dwarf_getlocation_addr(&attr, addr, &op,
 200                                                    &nops, 1) > 0)
 201                                 goto found;
 202                 }
 203                 return -ENOENT;
 204         }
 205 found:
 206         if (nops == 0)
 207                 /* TODO: Support const_value */
 208                 return -ENOENT;
 209
 210         if (op->atom == DW_OP_addr) {
 211 static_var:
 212                 if (!tvar)
 213                         return 0;
 214                 /* Static variables on memory (not stack), make @varname */
 215                 ret = strlen(dwarf_diename(vr_die));
 216                 tvar->value = zalloc(ret + 2);
 217                 if (tvar->value == NULL)
 218                         return -ENOMEM;
 219                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 220                 tvar->ref = alloc_trace_arg_ref((long)offs);
 221                 if (tvar->ref == NULL)
 222                         return -ENOMEM;
 223                 return 0;
 224         }
 225
 226         /* If this is based on frame buffer, set the offset */
 227         if (op->atom == DW_OP_fbreg) {
 228                 if (fb_ops == NULL)
 229                         return -ENOTSUP;
 230                 ref = true;
 231                 offs = op->number;
 232                 op = &fb_ops[0];
 233         }
 234
 235         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 236                 regn = op->atom - DW_OP_breg0;
 237                 offs += op->number;
 238                 ref = true;
 239         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 240                 regn = op->atom - DW_OP_reg0;
 241         } else if (op->atom == DW_OP_bregx) {
 242                 regn = op->number;
 243                 offs += op->number2;
 244                 ref = true;
 245         } else if (op->atom == DW_OP_regx) {
 246                 regn = op->number;
 247         } else {
 248                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 249                 return -ENOTSUP;
 250         }
 251
 252         if (!tvar)
 253                 return 0;
 254
 255         regs = get_arch_regstr(regn);
 256         if (!regs) {
 257                 /* This should be a bug in DWARF or this tool */
 258                 pr_warning("Mapping for the register number %u "
 259                            "missing on this architecture.\n", regn);
 260                 return -ERANGE;
 261         }
 262
 263         tvar->value = strdup(regs);
 264         if (tvar->value == NULL)
 265                 return -ENOMEM;
 266
 267         if (ref) {
 268                 tvar->ref = alloc_trace_arg_ref((long)offs);
 269                 if (tvar->ref == NULL)
 270                         return -ENOMEM;
 271         }
 272         return 0;
 273 }
 274
 275 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 276
 277 static int convert_variable_type(Dwarf_Die *vr_die,
 278                                  struct probe_trace_arg *tvar,
 279                                  const char *cast)
 280 {
 281         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 282         Dwarf_Die type;
 283         char buf[16];
 284         char sbuf[STRERR_BUFSIZE];
 285         int bsize, boffs, total;
 286         int ret;
 287
 288         /* TODO: check all types */
 289         if (cast && strcmp(cast, "string") != 0) {
 290                 /* Non string type is OK */
 291                 tvar->type = strdup(cast);
 292                 return (tvar->type == NULL) ? -ENOMEM : 0;
 293         }
 294
 295         bsize = dwarf_bitsize(vr_die);
 296         if (bsize > 0) {
 297                 /* This is a bitfield */
 298                 boffs = dwarf_bitoffset(vr_die);
 299                 total = dwarf_bytesize(vr_die);
 300                 if (boffs < 0 || total < 0)
 301                         return -ENOENT;
 302                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 303                                 BYTES_TO_BITS(total));
 304                 goto formatted;
 305         }
 306
 307         if (die_get_real_type(vr_die, &type) == NULL) {
 308                 pr_warning("Failed to get a type information of %s.\n",
 309                            dwarf_diename(vr_die));
 310                 return -ENOENT;
 311         }
 312
 313         pr_debug("%s type is %s.\n",
 314                  dwarf_diename(vr_die), dwarf_diename(&type));
 315
 316         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 317                 ret = dwarf_tag(&type);
 318                 if (ret != DW_TAG_pointer_type &&
 319                     ret != DW_TAG_array_type) {
 320                         pr_warning("Failed to cast into string: "
 321                                    "%s(%s) is not a pointer nor array.\n",
 322                                    dwarf_diename(vr_die), dwarf_diename(&type));
 323                         return -EINVAL;
 324                 }
 325                 if (die_get_real_type(&type, &type) == NULL) {
 326                         pr_warning("Failed to get a type"
 327                                    " information.\n");
 328                         return -ENOENT;
 329                 }
 330                 if (ret == DW_TAG_pointer_type) {
 331                         while (*ref_ptr)
 332                                 ref_ptr = &(*ref_ptr)->next;
 333                         /* Add new reference with offset +0 */
 334                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 335                         if (*ref_ptr == NULL) {
 336                                 pr_warning("Out of memory error\n");
 337                                 return -ENOMEM;
 338                         }
 339                 }
 340                 if (!die_compare_name(&type, "char") &&
 341                     !die_compare_name(&type, "unsigned char")) {
 342                         pr_warning("Failed to cast into string: "
 343                                    "%s is not (unsigned) char *.\n",
 344                                    dwarf_diename(vr_die));
 345                         return -EINVAL;
 346                 }
 347                 tvar->type = strdup(cast);
 348                 return (tvar->type == NULL) ? -ENOMEM : 0;
 349         }
 350
 351         ret = dwarf_bytesize(&type);
 352         if (ret <= 0)
 353                 /* No size ... try to use default type */
 354                 return 0;
 355         ret = BYTES_TO_BITS(ret);
 356
 357         /* Check the bitwidth */
 358         if (ret > MAX_BASIC_TYPE_BITS) {
 359                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 360                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 361                 ret = MAX_BASIC_TYPE_BITS;
 362         }
 363         ret = snprintf(buf, 16, "%c%d",
 364                        die_is_signed_type(&type) ? 's' : 'u', ret);
 365
 366 formatted:
 367         if (ret < 0 || ret >= 16) {
 368                 if (ret >= 16)
 369                         ret = -E2BIG;
 370                 pr_warning("Failed to convert variable type: %s\n",
 371                            strerror_r(-ret, sbuf, sizeof(sbuf)));
 372                 return ret;
 373         }
 374         tvar->type = strdup(buf);
 375         if (tvar->type == NULL)
 376                 return -ENOMEM;
 377         return 0;
 378 }
 379
 380 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 381                                     struct perf_probe_arg_field *field,
 382                                     struct probe_trace_arg_ref **ref_ptr,
 383                                     Dwarf_Die *die_mem)
 384 {
 385         struct probe_trace_arg_ref *ref = *ref_ptr;
 386         Dwarf_Die type;
 387         Dwarf_Word offs;
 388         int ret, tag;
 389
 390         pr_debug("converting %s in %s\n", field->name, varname);
 391         if (die_get_real_type(vr_die, &type) == NULL) {
 392                 pr_warning("Failed to get the type of %s.\n", varname);
 393                 return -ENOENT;
 394         }
 395         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 396         tag = dwarf_tag(&type);
 397
 398         if (field->name[0] == '[' &&
 399             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 400                 if (field->next)
 401                         /* Save original type for next field */
 402                         memcpy(die_mem, &type, sizeof(*die_mem));
 403                 /* Get the type of this array */
 404                 if (die_get_real_type(&type, &type) == NULL) {
 405                         pr_warning("Failed to get the type of %s.\n", varname);
 406                         return -ENOENT;
 407                 }
 408                 pr_debug2("Array real type: (%x)\n",
 409                          (unsigned)dwarf_dieoffset(&type));
 410                 if (tag == DW_TAG_pointer_type) {
 411                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 412                         if (ref == NULL)
 413                                 return -ENOMEM;
 414                         if (*ref_ptr)
 415                                 (*ref_ptr)->next = ref;
 416                         else
 417                                 *ref_ptr = ref;
 418                 }
 419                 ref->offset += dwarf_bytesize(&type) * field->index;
 420                 if (!field->next)
 421                         /* Save vr_die for converting types */
 422                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 423                 goto next;
 424         } else if (tag == DW_TAG_pointer_type) {
 425                 /* Check the pointer and dereference */
 426                 if (!field->ref) {
 427                         pr_err("Semantic error: %s must be referred by '->'\n",
 428                                field->name);
 429                         return -EINVAL;
 430                 }
 431                 /* Get the type pointed by this pointer */
 432                 if (die_get_real_type(&type, &type) == NULL) {
 433                         pr_warning("Failed to get the type of %s.\n", varname);
 434                         return -ENOENT;
 435                 }
 436                 /* Verify it is a data structure  */
 437                 tag = dwarf_tag(&type);
 438                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 439                         pr_warning("%s is not a data structure nor an union.\n",
 440                                    varname);
 441                         return -EINVAL;
 442                 }
 443
 444                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 445                 if (ref == NULL)
 446                         return -ENOMEM;
 447                 if (*ref_ptr)
 448                         (*ref_ptr)->next = ref;
 449                 else
 450                         *ref_ptr = ref;
 451         } else {
 452                 /* Verify it is a data structure  */
 453                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 454                         pr_warning("%s is not a data structure nor an union.\n",
 455                                    varname);
 456                         return -EINVAL;
 457                 }
 458                 if (field->name[0] == '[') {
 459                         pr_err("Semantic error: %s is not a pointer"
 460                                " nor array.\n", varname);
 461                         return -EINVAL;
 462                 }
 463                 /* While prcessing unnamed field, we don't care about this */
 464                 if (field->ref && dwarf_diename(vr_die)) {
 465                         pr_err("Semantic error: %s must be referred by '.'\n",
 466                                field->name);
 467                         return -EINVAL;
 468                 }
 469                 if (!ref) {
 470                         pr_warning("Structure on a register is not "
 471                                    "supported yet.\n");
 472                         return -ENOTSUP;
 473                 }
 474         }
 475
 476         if (die_find_member(&type, field->name, die_mem) == NULL) {
 477                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 478                            dwarf_diename(&type), field->name);
 479                 return -EINVAL;
 480         }
 481
 482         /* Get the offset of the field */
 483         if (tag == DW_TAG_union_type) {
 484                 offs = 0;
 485         } else {
 486                 ret = die_get_data_member_location(die_mem, &offs);
 487                 if (ret < 0) {
 488                         pr_warning("Failed to get the offset of %s.\n",
 489                                    field->name);
 490                         return ret;
 491                 }
 492         }
 493         ref->offset += (long)offs;
 494
 495         /* If this member is unnamed, we need to reuse this field */
 496         if (!dwarf_diename(die_mem))
 497                 return convert_variable_fields(die_mem, varname, field,
 498                                                 &ref, die_mem);
 499
 500 next:
 501         /* Converting next field */
 502         if (field->next)
 503                 return convert_variable_fields(die_mem, field->name,
 504                                         field->next, &ref, die_mem);
 505         else
 506                 return 0;
 507 }
 508
 509 /* Show a variables in kprobe event format */
 510 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 511 {
 512         Dwarf_Die die_mem;
 513         int ret;
 514
 515         pr_debug("Converting variable %s into trace event.\n",
 516                  dwarf_diename(vr_die));
 517
 518         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 519                                         &pf->sp_die, pf->tvar);
 520         if (ret == -ENOENT || ret == -EINVAL)
 521                 pr_err("Failed to find the location of %s at this address.\n"
 522                        " Perhaps, it has been optimized out.\n", pf->pvar->var);
 523         else if (ret == -ENOTSUP)
 524                 pr_err("Sorry, we don't support this variable location yet.\n");
 525         else if (ret == 0 && pf->pvar->field) {
 526                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 527                                               pf->pvar->field, &pf->tvar->ref,
 528                                               &die_mem);
 529                 vr_die = &die_mem;
 530         }
 531         if (ret == 0)
 532                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 533         /* *expr will be cached in libdw. Don't free it. */
 534         return ret;
 535 }
 536
 537 /* Find a variable in a scope DIE */
 538 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 539 {
 540         Dwarf_Die vr_die;
 541         char buf[32], *ptr;
 542         int ret = 0;
 543
 544         if (!is_c_varname(pf->pvar->var)) {
 545                 /* Copy raw parameters */
 546                 pf->tvar->value = strdup(pf->pvar->var);
 547                 if (pf->tvar->value == NULL)
 548                         return -ENOMEM;
 549                 if (pf->pvar->type) {
 550                         pf->tvar->type = strdup(pf->pvar->type);
 551                         if (pf->tvar->type == NULL)
 552                                 return -ENOMEM;
 553                 }
 554                 if (pf->pvar->name) {
 555                         pf->tvar->name = strdup(pf->pvar->name);
 556                         if (pf->tvar->name == NULL)
 557                                 return -ENOMEM;
 558                 } else
 559                         pf->tvar->name = NULL;
 560                 return 0;
 561         }
 562
 563         if (pf->pvar->name)
 564                 pf->tvar->name = strdup(pf->pvar->name);
 565         else {
 566                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 567                 if (ret < 0)
 568                         return ret;
 569                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 570                 if (ptr)
 571                         *ptr = '_';
 572                 pf->tvar->name = strdup(buf);
 573         }
 574         if (pf->tvar->name == NULL)
 575                 return -ENOMEM;
 576
 577         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 578         /* Search child die for local variables and parameters. */
 579         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 580                 /* Search again in global variables */
 581                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
 582                         pr_warning("Failed to find '%s' in this function.\n",
 583                                    pf->pvar->var);
 584                         ret = -ENOENT;
 585         }
 586         if (ret >= 0)
 587                 ret = convert_variable(&vr_die, pf);
 588
 589         return ret;
 590 }
 591
 592 /* Convert subprogram DIE to trace point */
 593 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 594                                   Dwarf_Addr paddr, bool retprobe,
 595                                   struct probe_trace_point *tp)
 596 {
 597         Dwarf_Addr eaddr, highaddr;
 598         GElf_Sym sym;
 599         const char *symbol;
 600
 601         /* Verify the address is correct */
 602         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 603                 pr_warning("Failed to get entry address of %s\n",
 604                            dwarf_diename(sp_die));
 605                 return -ENOENT;
 606         }
 607         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 608                 pr_warning("Failed to get end address of %s\n",
 609                            dwarf_diename(sp_die));
 610                 return -ENOENT;
 611         }
 612         if (paddr > highaddr) {
 613                 pr_warning("Offset specified is greater than size of %s\n",
 614                            dwarf_diename(sp_die));
 615                 return -EINVAL;
 616         }
 617
 618         symbol = dwarf_diename(sp_die);
 619         if (!symbol) {
 620                 /* Try to get the symbol name from symtab */
 621                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 622                 if (!symbol) {
 623                         pr_warning("Failed to find symbol at 0x%lx\n",
 624                                    (unsigned long)paddr);
 625                         return -ENOENT;
 626                 }
 627                 eaddr = sym.st_value;
 628         }
 629         tp->offset = (unsigned long)(paddr - eaddr);
 630         tp->address = (unsigned long)paddr;
 631         tp->symbol = strdup(symbol);
 632         if (!tp->symbol)
 633                 return -ENOMEM;
 634
 635         /* Return probe must be on the head of a subprogram */
 636         if (retprobe) {
 637                 if (eaddr != paddr) {
 638                         pr_warning("Return probe must be on the head of"
 639                                    " a real function.\n");
 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         size_t nops;
 653         int ret;
 654
 655         if (!sc_die) {
 656                 pr_err("Caller must pass a scope DIE. Program error.\n");
 657                 return -EINVAL;
 658         }
 659
 660         /* If not a real subprogram, find a real one */
 661         if (!die_is_func_def(sc_die)) {
 662                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 663                         pr_warning("Failed to find probe point in any "
 664                                    "functions.\n");
 665                         return -ENOENT;
 666                 }
 667         } else
 668                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 669
 670         /* Get the frame base attribute/ops from subprogram */
 671         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 672         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 673         if (ret <= 0 || nops == 0) {
 674                 pf->fb_ops = NULL;
 675 #if _ELFUTILS_PREREQ(0, 142)
 676         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 677                    pf->cfi != NULL) {
 678                 Dwarf_Frame *frame;
 679                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 680                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 681                         pr_warning("Failed to get call frame on 0x%jx\n",
 682                                    (uintmax_t)pf->addr);
 683                         return -ENOENT;
 684                 }
 685 #endif
 686         }
 687
 688         /* Call finder's callback handler */
 689         ret = pf->callback(sc_die, pf);
 690
 691         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 692         pf->fb_ops = NULL;
 693
 694         return ret;
 695 }
 696
 697 struct find_scope_param {
 698         const char *function;
 699         const char *file;
 700         int line;
 701         int diff;
 702         Dwarf_Die *die_mem;
 703         bool found;
 704 };
 705
 706 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 707 {
 708         struct find_scope_param *fsp = data;
 709         const char *file;
 710         int lno;
 711
 712         /* Skip if declared file name does not match */
 713         if (fsp->file) {
 714                 file = dwarf_decl_file(fn_die);
 715                 if (!file || strcmp(fsp->file, file) != 0)
 716                         return 0;
 717         }
 718         /* If the function name is given, that's what user expects */
 719         if (fsp->function) {
 720                 if (die_compare_name(fn_die, fsp->function)) {
 721                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 722                         fsp->found = true;
 723                         return 1;
 724                 }
 725         } else {
 726                 /* With the line number, find the nearest declared DIE */
 727                 dwarf_decl_line(fn_die, &lno);
 728                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 729                         /* Keep a candidate and continue */
 730                         fsp->diff = fsp->line - lno;
 731                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 732                         fsp->found = true;
 733                 }
 734         }
 735         return 0;
 736 }
 737
 738 /* Find an appropriate scope fits to given conditions */
 739 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 740 {
 741         struct find_scope_param fsp = {
 742                 .function = pf->pev->point.function,
 743                 .file = pf->fname,
 744                 .line = pf->lno,
 745                 .diff = INT_MAX,
 746                 .die_mem = die_mem,
 747                 .found = false,
 748         };
 749
 750         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 751
 752         return fsp.found ? die_mem : NULL;
 753 }
 754
 755 static int probe_point_line_walker(const char *fname, int lineno,
 756                                    Dwarf_Addr addr, void *data)
 757 {
 758         struct probe_finder *pf = data;
 759         Dwarf_Die *sc_die, die_mem;
 760         int ret;
 761
 762         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 763                 return 0;
 764
 765         pf->addr = addr;
 766         sc_die = find_best_scope(pf, &die_mem);
 767         if (!sc_die) {
 768                 pr_warning("Failed to find scope of probe point.\n");
 769                 return -ENOENT;
 770         }
 771
 772         ret = call_probe_finder(sc_die, pf);
 773
 774         /* Continue if no error, because the line will be in inline function */
 775         return ret < 0 ? ret : 0;
 776 }
 777
 778 /* Find probe point from its line number */
 779 static int find_probe_point_by_line(struct probe_finder *pf)
 780 {
 781         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 782 }
 783
 784 /* Find lines which match lazy pattern */
 785 static int find_lazy_match_lines(struct intlist *list,
 786                                  const char *fname, const char *pat)
 787 {
 788         FILE *fp;
 789         char *line = NULL;
 790         size_t line_len;
 791         ssize_t len;
 792         int count = 0, linenum = 1;
 793         char sbuf[STRERR_BUFSIZE];
 794
 795         fp = fopen(fname, "r");
 796         if (!fp) {
 797                 pr_warning("Failed to open %s: %s\n", fname,
 798                            strerror_r(errno, sbuf, sizeof(sbuf)));
 799                 return -errno;
 800         }
 801
 802         while ((len = getline(&line, &line_len, fp)) > 0) {
 803
 804                 if (line[len - 1] == '\n')
 805                         line[len - 1] = '\0';
 806
 807                 if (strlazymatch(line, pat)) {
 808                         intlist__add(list, linenum);
 809                         count++;
 810                 }
 811                 linenum++;
 812         }
 813
 814         if (ferror(fp))
 815                 count = -errno;
 816         free(line);
 817         fclose(fp);
 818
 819         if (count == 0)
 820                 pr_debug("No matched lines found in %s.\n", fname);
 821         return count;
 822 }
 823
 824 static int probe_point_lazy_walker(const char *fname, int lineno,
 825                                    Dwarf_Addr addr, void *data)
 826 {
 827         struct probe_finder *pf = data;
 828         Dwarf_Die *sc_die, die_mem;
 829         int ret;
 830
 831         if (!intlist__has_entry(pf->lcache, lineno) ||
 832             strtailcmp(fname, pf->fname) != 0)
 833                 return 0;
 834
 835         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 836                  lineno, (unsigned long long)addr);
 837         pf->addr = addr;
 838         pf->lno = lineno;
 839         sc_die = find_best_scope(pf, &die_mem);
 840         if (!sc_die) {
 841                 pr_warning("Failed to find scope of probe point.\n");
 842                 return -ENOENT;
 843         }
 844
 845         ret = call_probe_finder(sc_die, pf);
 846
 847         /*
 848          * Continue if no error, because the lazy pattern will match
 849          * to other lines
 850          */
 851         return ret < 0 ? ret : 0;
 852 }
 853
 854 /* Find probe points from lazy pattern  */
 855 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 856 {
 857         int ret = 0;
 858         char *fpath;
 859
 860         if (intlist__empty(pf->lcache)) {
 861                 const char *comp_dir;
 862
 863                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 864                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 865                 if (ret < 0) {
 866                         pr_warning("Failed to find source file path.\n");
 867                         return ret;
 868                 }
 869
 870                 /* Matching lazy line pattern */
 871                 ret = find_lazy_match_lines(pf->lcache, fpath,
 872                                             pf->pev->point.lazy_line);
 873                 free(fpath);
 874                 if (ret <= 0)
 875                         return ret;
 876         }
 877
 878         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 879 }
 880
 881 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 882 {
 883         struct probe_finder *pf = data;
 884         struct perf_probe_point *pp = &pf->pev->point;
 885         Dwarf_Addr addr;
 886         int ret;
 887
 888         if (pp->lazy_line)
 889                 ret = find_probe_point_lazy(in_die, pf);
 890         else {
 891                 /* Get probe address */
 892                 if (dwarf_entrypc(in_die, &addr) != 0) {
 893                         pr_warning("Failed to get entry address of %s.\n",
 894                                    dwarf_diename(in_die));
 895                         return -ENOENT;
 896                 }
 897                 pf->addr = addr;
 898                 pf->addr += pp->offset;
 899                 pr_debug("found inline addr: 0x%jx\n",
 900                          (uintmax_t)pf->addr);
 901
 902                 ret = call_probe_finder(in_die, pf);
 903         }
 904
 905         return ret;
 906 }
 907
 908 /* Callback parameter with return value for libdw */
 909 struct dwarf_callback_param {
 910         void *data;
 911         int retval;
 912 };
 913
 914 /* Search function from function name */
 915 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 916 {
 917         struct dwarf_callback_param *param = data;
 918         struct probe_finder *pf = param->data;
 919         struct perf_probe_point *pp = &pf->pev->point;
 920
 921         /* Check tag and diename */
 922         if (!die_is_func_def(sp_die) ||
 923             !die_compare_name(sp_die, pp->function))
 924                 return DWARF_CB_OK;
 925
 926         /* Check declared file */
 927         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 928                 return DWARF_CB_OK;
 929
 930         pf->fname = dwarf_decl_file(sp_die);
 931         if (pp->line) { /* Function relative line */
 932                 dwarf_decl_line(sp_die, &pf->lno);
 933                 pf->lno += pp->line;
 934                 param->retval = find_probe_point_by_line(pf);
 935         } else if (die_is_func_instance(sp_die)) {
 936                 /* Instances always have the entry address */
 937                 dwarf_entrypc(sp_die, &pf->addr);
 938                 /* Real function */
 939                 if (pp->lazy_line)
 940                         param->retval = find_probe_point_lazy(sp_die, pf);
 941                 else {
 942                         pf->addr += pp->offset;
 943                         /* TODO: Check the address in this function */
 944                         param->retval = call_probe_finder(sp_die, pf);
 945                 }
 946         } else
 947                 /* Inlined function: search instances */
 948                 param->retval = die_walk_instances(sp_die,
 949                                         probe_point_inline_cb, (void *)pf);
 950
 951         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 952 }
 953
 954 static int find_probe_point_by_func(struct probe_finder *pf)
 955 {
 956         struct dwarf_callback_param _param = {.data = (void *)pf,
 957                                               .retval = 0};
 958         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 959         return _param.retval;
 960 }
 961
 962 struct pubname_callback_param {
 963         char *function;
 964         char *file;
 965         Dwarf_Die *cu_die;
 966         Dwarf_Die *sp_die;
 967         int found;
 968 };
 969
 970 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
 971 {
 972         struct pubname_callback_param *param = data;
 973
 974         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
 975                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
 976                         return DWARF_CB_OK;
 977
 978                 if (die_compare_name(param->sp_die, param->function)) {
 979                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
 980                                 return DWARF_CB_OK;
 981
 982                         if (param->file &&
 983                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
 984                                 return DWARF_CB_OK;
 985
 986                         param->found = 1;
 987                         return DWARF_CB_ABORT;
 988                 }
 989         }
 990
 991         return DWARF_CB_OK;
 992 }
 993
 994 /* Find probe points from debuginfo */
 995 static int debuginfo__find_probes(struct debuginfo *dbg,
 996                                   struct probe_finder *pf)
 997 {
 998         struct perf_probe_point *pp = &pf->pev->point;
 999         Dwarf_Off off, noff;
1000         size_t cuhl;
1001         Dwarf_Die *diep;
1002         int ret = 0;
1003
1004 #if _ELFUTILS_PREREQ(0, 142)
1005         Elf *elf;
1006         GElf_Ehdr ehdr;
1007         GElf_Shdr shdr;
1008
1009         /* Get the call frame information from this dwarf */
1010         elf = dwarf_getelf(dbg->dbg);
1011         if (elf == NULL)
1012                 return -EINVAL;
1013
1014         if (gelf_getehdr(elf, &ehdr) == NULL)
1015                 return -EINVAL;
1016
1017         if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1018             shdr.sh_type == SHT_PROGBITS) {
1019                 pf->cfi = dwarf_getcfi_elf(elf);
1020         } else {
1021                 pf->cfi = dwarf_getcfi(dbg->dbg);
1022         }
1023 #endif
1024
1025         off = 0;
1026         pf->lcache = intlist__new(NULL);
1027         if (!pf->lcache)
1028                 return -ENOMEM;
1029
1030         /* Fastpath: lookup by function name from .debug_pubnames section */
1031         if (pp->function) {
1032                 struct pubname_callback_param pubname_param = {
1033                         .function = pp->function,
1034                         .file     = pp->file,
1035                         .cu_die   = &pf->cu_die,
1036                         .sp_die   = &pf->sp_die,
1037                         .found    = 0,
1038                 };
1039                 struct dwarf_callback_param probe_param = {
1040                         .data = pf,
1041                 };
1042
1043                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1044                                   &pubname_param, 0);
1045                 if (pubname_param.found) {
1046                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1047                         if (ret)
1048                                 goto found;
1049                 }
1050         }
1051
1052         /* Loop on CUs (Compilation Unit) */
1053         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1054                 /* Get the DIE(Debugging Information Entry) of this CU */
1055                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1056                 if (!diep)
1057                         continue;
1058
1059                 /* Check if target file is included. */
1060                 if (pp->file)
1061                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1062                 else
1063                         pf->fname = NULL;
1064
1065                 if (!pp->file || pf->fname) {
1066                         if (pp->function)
1067                                 ret = find_probe_point_by_func(pf);
1068                         else if (pp->lazy_line)
1069                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1070                         else {
1071                                 pf->lno = pp->line;
1072                                 ret = find_probe_point_by_line(pf);
1073                         }
1074                         if (ret < 0)
1075                                 break;
1076                 }
1077                 off = noff;
1078         }
1079
1080 found:
1081         intlist__delete(pf->lcache);
1082         pf->lcache = NULL;
1083
1084         return ret;
1085 }
1086
1087 struct local_vars_finder {
1088         struct probe_finder *pf;
1089         struct perf_probe_arg *args;
1090         int max_args;
1091         int nargs;
1092         int ret;
1093 };
1094
1095 /* Collect available variables in this scope */
1096 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1097 {
1098         struct local_vars_finder *vf = data;
1099         struct probe_finder *pf = vf->pf;
1100         int tag;
1101
1102         tag = dwarf_tag(die_mem);
1103         if (tag == DW_TAG_formal_parameter ||
1104             tag == DW_TAG_variable) {
1105                 if (convert_variable_location(die_mem, vf->pf->addr,
1106                                               vf->pf->fb_ops, &pf->sp_die,
1107                                               NULL) == 0) {
1108                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1109                         if (vf->args[vf->nargs].var == NULL) {
1110                                 vf->ret = -ENOMEM;
1111                                 return DIE_FIND_CB_END;
1112                         }
1113                         pr_debug(" %s", vf->args[vf->nargs].var);
1114                         vf->nargs++;
1115                 }
1116         }
1117
1118         if (dwarf_haspc(die_mem, vf->pf->addr))
1119                 return DIE_FIND_CB_CONTINUE;
1120         else
1121                 return DIE_FIND_CB_SIBLING;
1122 }
1123
1124 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1125                              struct perf_probe_arg *args)
1126 {
1127         Dwarf_Die die_mem;
1128         int i;
1129         int n = 0;
1130         struct local_vars_finder vf = {.pf = pf, .args = args,
1131                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1132
1133         for (i = 0; i < pf->pev->nargs; i++) {
1134                 /* var never be NULL */
1135                 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1136                         pr_debug("Expanding $vars into:");
1137                         vf.nargs = n;
1138                         /* Special local variables */
1139                         die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1140                                        &die_mem);
1141                         pr_debug(" (%d)\n", vf.nargs - n);
1142                         if (vf.ret < 0)
1143                                 return vf.ret;
1144                         n = vf.nargs;
1145                 } else {
1146                         /* Copy normal argument */
1147                         args[n] = pf->pev->args[i];
1148                         n++;
1149                 }
1150         }
1151         return n;
1152 }
1153
1154 /* Add a found probe point into trace event list */
1155 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1156 {
1157         struct trace_event_finder *tf =
1158                         container_of(pf, struct trace_event_finder, pf);
1159         struct probe_trace_event *tev;
1160         struct perf_probe_arg *args;
1161         int ret, i;
1162
1163         /* Check number of tevs */
1164         if (tf->ntevs == tf->max_tevs) {
1165                 pr_warning("Too many( > %d) probe point found.\n",
1166                            tf->max_tevs);
1167                 return -ERANGE;
1168         }
1169         tev = &tf->tevs[tf->ntevs++];
1170
1171         /* Trace point should be converted from subprogram DIE */
1172         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1173                                      pf->pev->point.retprobe, &tev->point);
1174         if (ret < 0)
1175                 return ret;
1176
1177         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1178                  tev->point.offset);
1179
1180         /* Expand special probe argument if exist */
1181         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1182         if (args == NULL)
1183                 return -ENOMEM;
1184
1185         ret = expand_probe_args(sc_die, pf, args);
1186         if (ret < 0)
1187                 goto end;
1188
1189         tev->nargs = ret;
1190         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1191         if (tev->args == NULL) {
1192                 ret = -ENOMEM;
1193                 goto end;
1194         }
1195
1196         /* Find each argument */
1197         for (i = 0; i < tev->nargs; i++) {
1198                 pf->pvar = &args[i];
1199                 pf->tvar = &tev->args[i];
1200                 /* Variable should be found from scope DIE */
1201                 ret = find_variable(sc_die, pf);
1202                 if (ret != 0)
1203                         break;
1204         }
1205
1206 end:
1207         free(args);
1208         return ret;
1209 }
1210
1211 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1212 int debuginfo__find_trace_events(struct debuginfo *dbg,
1213                                  struct perf_probe_event *pev,
1214                                  struct probe_trace_event **tevs, int max_tevs)
1215 {
1216         struct trace_event_finder tf = {
1217                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1218                         .mod = dbg->mod, .max_tevs = max_tevs};
1219         int ret;
1220
1221         /* Allocate result tevs array */
1222         *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1223         if (*tevs == NULL)
1224                 return -ENOMEM;
1225
1226         tf.tevs = *tevs;
1227         tf.ntevs = 0;
1228
1229         ret = debuginfo__find_probes(dbg, &tf.pf);
1230         if (ret < 0) {
1231                 zfree(tevs);
1232                 return ret;
1233         }
1234
1235         return (ret < 0) ? ret : tf.ntevs;
1236 }
1237
1238 #define MAX_VAR_LEN 64
1239
1240 /* Collect available variables in this scope */
1241 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1242 {
1243         struct available_var_finder *af = data;
1244         struct variable_list *vl;
1245         char buf[MAX_VAR_LEN];
1246         int tag, ret;
1247
1248         vl = &af->vls[af->nvls - 1];
1249
1250         tag = dwarf_tag(die_mem);
1251         if (tag == DW_TAG_formal_parameter ||
1252             tag == DW_TAG_variable) {
1253                 ret = convert_variable_location(die_mem, af->pf.addr,
1254                                                 af->pf.fb_ops, &af->pf.sp_die,
1255                                                 NULL);
1256                 if (ret == 0) {
1257                         ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1258                         pr_debug2("Add new var: %s\n", buf);
1259                         if (ret > 0)
1260                                 strlist__add(vl->vars, buf);
1261                 }
1262         }
1263
1264         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1265                 return DIE_FIND_CB_CONTINUE;
1266         else
1267                 return DIE_FIND_CB_SIBLING;
1268 }
1269
1270 /* Add a found vars into available variables list */
1271 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1272 {
1273         struct available_var_finder *af =
1274                         container_of(pf, struct available_var_finder, pf);
1275         struct variable_list *vl;
1276         Dwarf_Die die_mem;
1277         int ret;
1278
1279         /* Check number of tevs */
1280         if (af->nvls == af->max_vls) {
1281                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1282                 return -ERANGE;
1283         }
1284         vl = &af->vls[af->nvls++];
1285
1286         /* Trace point should be converted from subprogram DIE */
1287         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1288                                      pf->pev->point.retprobe, &vl->point);
1289         if (ret < 0)
1290                 return ret;
1291
1292         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1293                  vl->point.offset);
1294
1295         /* Find local variables */
1296         vl->vars = strlist__new(true, NULL);
1297         if (vl->vars == NULL)
1298                 return -ENOMEM;
1299         af->child = true;
1300         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1301
1302         /* Find external variables */
1303         if (!af->externs)
1304                 goto out;
1305         /* Don't need to search child DIE for externs. */
1306         af->child = false;
1307         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1308
1309 out:
1310         if (strlist__empty(vl->vars)) {
1311                 strlist__delete(vl->vars);
1312                 vl->vars = NULL;
1313         }
1314
1315         return ret;
1316 }
1317
1318 /*
1319  * Find available variables at given probe point
1320  * Return the number of found probe points. Return 0 if there is no
1321  * matched probe point. Return <0 if an error occurs.
1322  */
1323 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1324                                       struct perf_probe_event *pev,
1325                                       struct variable_list **vls,
1326                                       int max_vls, bool externs)
1327 {
1328         struct available_var_finder af = {
1329                         .pf = {.pev = pev, .callback = add_available_vars},
1330                         .mod = dbg->mod,
1331                         .max_vls = max_vls, .externs = externs};
1332         int ret;
1333
1334         /* Allocate result vls array */
1335         *vls = zalloc(sizeof(struct variable_list) * max_vls);
1336         if (*vls == NULL)
1337                 return -ENOMEM;
1338
1339         af.vls = *vls;
1340         af.nvls = 0;
1341
1342         ret = debuginfo__find_probes(dbg, &af.pf);
1343         if (ret < 0) {
1344                 /* Free vlist for error */
1345                 while (af.nvls--) {
1346                         zfree(&af.vls[af.nvls].point.symbol);
1347                         strlist__delete(af.vls[af.nvls].vars);
1348                 }
1349                 zfree(vls);
1350                 return ret;
1351         }
1352
1353         return (ret < 0) ? ret : af.nvls;
1354 }
1355
1356 /* Reverse search */
1357 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1358                                 struct perf_probe_point *ppt)
1359 {
1360         Dwarf_Die cudie, spdie, indie;
1361         Dwarf_Addr _addr = 0, baseaddr = 0;
1362         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1363         int baseline = 0, lineno = 0, ret = 0;
1364
1365         /* Find cu die */
1366         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1367                 pr_warning("Failed to find debug information for address %lx\n",
1368                            addr);
1369                 ret = -EINVAL;
1370                 goto end;
1371         }
1372
1373         /* Find a corresponding line (filename and lineno) */
1374         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1375         /* Don't care whether it failed or not */
1376
1377         /* Find a corresponding function (name, baseline and baseaddr) */
1378         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1379                 /* Get function entry information */
1380                 func = basefunc = dwarf_diename(&spdie);
1381                 if (!func ||
1382                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1383                     dwarf_decl_line(&spdie, &baseline) != 0) {
1384                         lineno = 0;
1385                         goto post;
1386                 }
1387
1388                 fname = dwarf_decl_file(&spdie);
1389                 if (addr == (unsigned long)baseaddr) {
1390                         /* Function entry - Relative line number is 0 */
1391                         lineno = baseline;
1392                         goto post;
1393                 }
1394
1395                 /* Track down the inline functions step by step */
1396                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1397                                                 &indie)) {
1398                         /* There is an inline function */
1399                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1400                             _addr == addr) {
1401                                 /*
1402                                  * addr is at an inline function entry.
1403                                  * In this case, lineno should be the call-site
1404                                  * line number. (overwrite lineinfo)
1405                                  */
1406                                 lineno = die_get_call_lineno(&indie);
1407                                 fname = die_get_call_file(&indie);
1408                                 break;
1409                         } else {
1410                                 /*
1411                                  * addr is in an inline function body.
1412                                  * Since lineno points one of the lines
1413                                  * of the inline function, baseline should
1414                                  * be the entry line of the inline function.
1415                                  */
1416                                 tmp = dwarf_diename(&indie);
1417                                 if (!tmp ||
1418                                     dwarf_decl_line(&indie, &baseline) != 0)
1419                                         break;
1420                                 func = tmp;
1421                                 spdie = indie;
1422                         }
1423                 }
1424                 /* Verify the lineno and baseline are in a same file */
1425                 tmp = dwarf_decl_file(&spdie);
1426                 if (!tmp || strcmp(tmp, fname) != 0)
1427                         lineno = 0;
1428         }
1429
1430 post:
1431         /* Make a relative line number or an offset */
1432         if (lineno)
1433                 ppt->line = lineno - baseline;
1434         else if (basefunc) {
1435                 ppt->offset = addr - (unsigned long)baseaddr;
1436                 func = basefunc;
1437         }
1438
1439         /* Duplicate strings */
1440         if (func) {
1441                 ppt->function = strdup(func);
1442                 if (ppt->function == NULL) {
1443                         ret = -ENOMEM;
1444                         goto end;
1445                 }
1446         }
1447         if (fname) {
1448                 ppt->file = strdup(fname);
1449                 if (ppt->file == NULL) {
1450                         zfree(&ppt->function);
1451                         ret = -ENOMEM;
1452                         goto end;
1453                 }
1454         }
1455 end:
1456         if (ret == 0 && (fname || func))
1457                 ret = 1;        /* Found a point */
1458         return ret;
1459 }
1460
1461 /* Add a line and store the src path */
1462 static int line_range_add_line(const char *src, unsigned int lineno,
1463                                struct line_range *lr)
1464 {
1465         /* Copy source path */
1466         if (!lr->path) {
1467                 lr->path = strdup(src);
1468                 if (lr->path == NULL)
1469                         return -ENOMEM;
1470         }
1471         return intlist__add(lr->line_list, lineno);
1472 }
1473
1474 static int line_range_walk_cb(const char *fname, int lineno,
1475                               Dwarf_Addr addr __maybe_unused,
1476                               void *data)
1477 {
1478         struct line_finder *lf = data;
1479         int err;
1480
1481         if ((strtailcmp(fname, lf->fname) != 0) ||
1482             (lf->lno_s > lineno || lf->lno_e < lineno))
1483                 return 0;
1484
1485         err = line_range_add_line(fname, lineno, lf->lr);
1486         if (err < 0 && err != -EEXIST)
1487                 return err;
1488
1489         return 0;
1490 }
1491
1492 /* Find line range from its line number */
1493 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1494 {
1495         int ret;
1496
1497         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1498
1499         /* Update status */
1500         if (ret >= 0)
1501                 if (!intlist__empty(lf->lr->line_list))
1502                         ret = lf->found = 1;
1503                 else
1504                         ret = 0;        /* Lines are not found */
1505         else {
1506                 zfree(&lf->lr->path);
1507         }
1508         return ret;
1509 }
1510
1511 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1512 {
1513         int ret = find_line_range_by_line(in_die, data);
1514
1515         /*
1516          * We have to check all instances of inlined function, because
1517          * some execution paths can be optimized out depends on the
1518          * function argument of instances. However, if an error occurs,
1519          * it should be handled by the caller.
1520          */
1521         return ret < 0 ? ret : 0;
1522 }
1523
1524 /* Search function definition from function name */
1525 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1526 {
1527         struct dwarf_callback_param *param = data;
1528         struct line_finder *lf = param->data;
1529         struct line_range *lr = lf->lr;
1530
1531         /* Check declared file */
1532         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1533                 return DWARF_CB_OK;
1534
1535         if (die_is_func_def(sp_die) &&
1536             die_compare_name(sp_die, lr->function)) {
1537                 lf->fname = dwarf_decl_file(sp_die);
1538                 dwarf_decl_line(sp_die, &lr->offset);
1539                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1540                 lf->lno_s = lr->offset + lr->start;
1541                 if (lf->lno_s < 0)      /* Overflow */
1542                         lf->lno_s = INT_MAX;
1543                 lf->lno_e = lr->offset + lr->end;
1544                 if (lf->lno_e < 0)      /* Overflow */
1545                         lf->lno_e = INT_MAX;
1546                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1547                 lr->start = lf->lno_s;
1548                 lr->end = lf->lno_e;
1549                 if (!die_is_func_instance(sp_die))
1550                         param->retval = die_walk_instances(sp_die,
1551                                                 line_range_inline_cb, lf);
1552                 else
1553                         param->retval = find_line_range_by_line(sp_die, lf);
1554                 return DWARF_CB_ABORT;
1555         }
1556         return DWARF_CB_OK;
1557 }
1558
1559 static int find_line_range_by_func(struct line_finder *lf)
1560 {
1561         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1562         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1563         return param.retval;
1564 }
1565
1566 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1567 {
1568         struct line_finder lf = {.lr = lr, .found = 0};
1569         int ret = 0;
1570         Dwarf_Off off = 0, noff;
1571         size_t cuhl;
1572         Dwarf_Die *diep;
1573         const char *comp_dir;
1574
1575         /* Fastpath: lookup by function name from .debug_pubnames section */
1576         if (lr->function) {
1577                 struct pubname_callback_param pubname_param = {
1578                         .function = lr->function, .file = lr->file,
1579                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1580                 struct dwarf_callback_param line_range_param = {
1581                         .data = (void *)&lf, .retval = 0};
1582
1583                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1584                                   &pubname_param, 0);
1585                 if (pubname_param.found) {
1586                         line_range_search_cb(&lf.sp_die, &line_range_param);
1587                         if (lf.found)
1588                                 goto found;
1589                 }
1590         }
1591
1592         /* Loop on CUs (Compilation Unit) */
1593         while (!lf.found && ret >= 0) {
1594                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1595                                  NULL, NULL, NULL) != 0)
1596                         break;
1597
1598                 /* Get the DIE(Debugging Information Entry) of this CU */
1599                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1600                 if (!diep)
1601                         continue;
1602
1603                 /* Check if target file is included. */
1604                 if (lr->file)
1605                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1606                 else
1607                         lf.fname = 0;
1608
1609                 if (!lr->file || lf.fname) {
1610                         if (lr->function)
1611                                 ret = find_line_range_by_func(&lf);
1612                         else {
1613                                 lf.lno_s = lr->start;
1614                                 lf.lno_e = lr->end;
1615                                 ret = find_line_range_by_line(NULL, &lf);
1616                         }
1617                 }
1618                 off = noff;
1619         }
1620
1621 found:
1622         /* Store comp_dir */
1623         if (lf.found) {
1624                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1625                 if (comp_dir) {
1626                         lr->comp_dir = strdup(comp_dir);
1627                         if (!lr->comp_dir)
1628                                 ret = -ENOMEM;
1629                 }
1630         }
1631
1632         pr_debug("path: %s\n", lr->path);
1633         return (ret < 0) ? ret : lf.found;
1634 }
1635
1636 /*
1637  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1638  * and chop off leading directories that do not exist. Result is passed back as
1639  * a newly allocated path on success.
1640  * Return 0 if file was found and readable, -errno otherwise.
1641  */
1642 int get_real_path(const char *raw_path, const char *comp_dir,
1643                          char **new_path)
1644 {
1645         const char *prefix = symbol_conf.source_prefix;
1646
1647         if (!prefix) {
1648                 if (raw_path[0] != '/' && comp_dir)
1649                         /* If not an absolute path, try to use comp_dir */
1650                         prefix = comp_dir;
1651                 else {
1652                         if (access(raw_path, R_OK) == 0) {
1653                                 *new_path = strdup(raw_path);
1654                                 return *new_path ? 0 : -ENOMEM;
1655                         } else
1656                                 return -errno;
1657                 }
1658         }
1659
1660         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1661         if (!*new_path)
1662                 return -ENOMEM;
1663
1664         for (;;) {
1665                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1666
1667                 if (access(*new_path, R_OK) == 0)
1668                         return 0;
1669
1670                 if (!symbol_conf.source_prefix) {
1671                         /* In case of searching comp_dir, don't retry */
1672                         zfree(new_path);
1673                         return -errno;
1674                 }
1675
1676                 switch (errno) {
1677                 case ENAMETOOLONG:
1678                 case ENOENT:
1679                 case EROFS:
1680                 case EFAULT:
1681                         raw_path = strchr(++raw_path, '/');
1682                         if (!raw_path) {
1683                                 zfree(new_path);
1684                                 return -ENOENT;
1685                         }
1686                         continue;
1687
1688                 default:
1689                         zfree(new_path);
1690                         return -errno;
1691                 }
1692         }
1693 }