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