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