Pileus Git - ~andy/linux/blob - 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 <getopt.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <stdarg.h>
  33 #include <dwarf-regs.h>
  34
  35 #include <linux/bitops.h>
  36 #include "event.h"
  37 #include "debug.h"
  38 #include "util.h"
  39 #include "symbol.h"
  40 #include "probe-finder.h"
  41
  42 /* Kprobe tracer basic type is up to u64 */
  43 #define MAX_BASIC_TYPE_BITS     64
  44
  45 /* Line number list operations */
  46
  47 /* Add a line to line number list */
  48 static int line_list__add_line(struct list_head *head, int line)
  49 {
  50         struct line_node *ln;
  51         struct list_head *p;
  52
  53         /* Reverse search, because new line will be the last one */
  54         list_for_each_entry_reverse(ln, head, list) {
  55                 if (ln->line < line) {
  56                         p = &ln->list;
  57                         goto found;
  58                 } else if (ln->line == line)    /* Already exist */
  59                         return 1;
  60         }
  61         /* List is empty, or the smallest entry */
  62         p = head;
  63 found:
  64         pr_debug("line list: add a line %u\n", line);
  65         ln = zalloc(sizeof(struct line_node));
  66         if (ln == NULL)
  67                 return -ENOMEM;
  68         ln->line = line;
  69         INIT_LIST_HEAD(&ln->list);
  70         list_add(&ln->list, p);
  71         return 0;
  72 }
  73
  74 /* Check if the line in line number list */
  75 static int line_list__has_line(struct list_head *head, int line)
  76 {
  77         struct line_node *ln;
  78
  79         /* Reverse search, because new line will be the last one */
  80         list_for_each_entry(ln, head, list)
  81                 if (ln->line == line)
  82                         return 1;
  83
  84         return 0;
  85 }
  86
  87 /* Init line number list */
  88 static void line_list__init(struct list_head *head)
  89 {
  90         INIT_LIST_HEAD(head);
  91 }
  92
  93 /* Free line number list */
  94 static void line_list__free(struct list_head *head)
  95 {
  96         struct line_node *ln;
  97         while (!list_empty(head)) {
  98                 ln = list_first_entry(head, struct line_node, list);
  99                 list_del(&ln->list);
 100                 free(ln);
 101         }
 102 }
 103
 104 /* Dwarf FL wrappers */
 105 static char *debuginfo_path;    /* Currently dummy */
 106
 107 static const Dwfl_Callbacks offline_callbacks = {
 108         .find_debuginfo = dwfl_standard_find_debuginfo,
 109         .debuginfo_path = &debuginfo_path,
 110
 111         .section_address = dwfl_offline_section_address,
 112
 113         /* We use this table for core files too.  */
 114         .find_elf = dwfl_build_id_find_elf,
 115 };
 116
 117 /* Get a Dwarf from offline image */
 118 static int debuginfo__init_offline_dwarf(struct debuginfo *self,
 119                                          const char *path)
 120 {
 121         int fd;
 122
 123         fd = open(path, O_RDONLY);
 124         if (fd < 0)
 125                 return fd;
 126
 127         self->dwfl = dwfl_begin(&offline_callbacks);
 128         if (!self->dwfl)
 129                 goto error;
 130
 131         self->mod = dwfl_report_offline(self->dwfl, "", "", fd);
 132         if (!self->mod)
 133                 goto error;
 134
 135         self->dbg = dwfl_module_getdwarf(self->mod, &self->bias);
 136         if (!self->dbg)
 137                 goto error;
 138
 139         return 0;
 140 error:
 141         if (self->dwfl)
 142                 dwfl_end(self->dwfl);
 143         else
 144                 close(fd);
 145         memset(self, 0, sizeof(*self));
 146
 147         return -ENOENT;
 148 }
 149
 150 #if _ELFUTILS_PREREQ(0, 148)
 151 /* This method is buggy if elfutils is older than 0.148 */
 152 static int __linux_kernel_find_elf(Dwfl_Module *mod,
 153                                    void **userdata,
 154                                    const char *module_name,
 155                                    Dwarf_Addr base,
 156                                    char **file_name, Elf **elfp)
 157 {
 158         int fd;
 159         const char *path = kernel_get_module_path(module_name);
 160
 161         pr_debug2("Use file %s for %s\n", path, module_name);
 162         if (path) {
 163                 fd = open(path, O_RDONLY);
 164                 if (fd >= 0) {
 165                         *file_name = strdup(path);
 166                         return fd;
 167                 }
 168         }
 169         /* If failed, try to call standard method */
 170         return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
 171                                           file_name, elfp);
 172 }
 173
 174 static const Dwfl_Callbacks kernel_callbacks = {
 175         .find_debuginfo = dwfl_standard_find_debuginfo,
 176         .debuginfo_path = &debuginfo_path,
 177
 178         .find_elf = __linux_kernel_find_elf,
 179         .section_address = dwfl_linux_kernel_module_section_address,
 180 };
 181
 182 /* Get a Dwarf from live kernel image */
 183 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
 184                                                Dwarf_Addr addr)
 185 {
 186         self->dwfl = dwfl_begin(&kernel_callbacks);
 187         if (!self->dwfl)
 188                 return -EINVAL;
 189
 190         /* Load the kernel dwarves: Don't care the result here */
 191         dwfl_linux_kernel_report_kernel(self->dwfl);
 192         dwfl_linux_kernel_report_modules(self->dwfl);
 193
 194         self->dbg = dwfl_addrdwarf(self->dwfl, addr, &self->bias);
 195         /* Here, check whether we could get a real dwarf */
 196         if (!self->dbg) {
 197                 pr_debug("Failed to find kernel dwarf at %lx\n",
 198                          (unsigned long)addr);
 199                 dwfl_end(self->dwfl);
 200                 memset(self, 0, sizeof(*self));
 201                 return -ENOENT;
 202         }
 203
 204         return 0;
 205 }
 206 #else
 207 /* With older elfutils, this just support kernel module... */
 208 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
 209                                                Dwarf_Addr addr __maybe_unused)
 210 {
 211         const char *path = kernel_get_module_path("kernel");
 212
 213         if (!path) {
 214                 pr_err("Failed to find vmlinux path\n");
 215                 return -ENOENT;
 216         }
 217
 218         pr_debug2("Use file %s for debuginfo\n", path);
 219         return debuginfo__init_offline_dwarf(self, path);
 220 }
 221 #endif
 222
 223 struct debuginfo *debuginfo__new(const char *path)
 224 {
 225         struct debuginfo *self = zalloc(sizeof(struct debuginfo));
 226         if (!self)
 227                 return NULL;
 228
 229         if (debuginfo__init_offline_dwarf(self, path) < 0) {
 230                 free(self);
 231                 self = NULL;
 232         }
 233
 234         return self;
 235 }
 236
 237 struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
 238 {
 239         struct debuginfo *self = zalloc(sizeof(struct debuginfo));
 240         if (!self)
 241                 return NULL;
 242
 243         if (debuginfo__init_online_kernel_dwarf(self, (Dwarf_Addr)addr) < 0) {
 244                 free(self);
 245                 self = NULL;
 246         }
 247
 248         return self;
 249 }
 250
 251 void debuginfo__delete(struct debuginfo *self)
 252 {
 253         if (self) {
 254                 if (self->dwfl)
 255                         dwfl_end(self->dwfl);
 256                 free(self);
 257         }
 258 }
 259
 260 /*
 261  * Probe finder related functions
 262  */
 263
 264 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 265 {
 266         struct probe_trace_arg_ref *ref;
 267         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 268         if (ref != NULL)
 269                 ref->offset = offs;
 270         return ref;
 271 }
 272
 273 /*
 274  * Convert a location into trace_arg.
 275  * If tvar == NULL, this just checks variable can be converted.
 276  * If fentry == true and vr_die is a parameter, do huristic search
 277  * for the location fuzzed by function entry mcount.
 278  */
 279 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 280                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 281                                      struct probe_trace_arg *tvar)
 282 {
 283         Dwarf_Attribute attr;
 284         Dwarf_Addr tmp = 0;
 285         Dwarf_Op *op;
 286         size_t nops;
 287         unsigned int regn;
 288         Dwarf_Word offs = 0;
 289         bool ref = false;
 290         const char *regs;
 291         int ret;
 292
 293         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 294                 goto static_var;
 295
 296         /* TODO: handle more than 1 exprs */
 297         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 298                 return -EINVAL; /* Broken DIE ? */
 299         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 300                 ret = dwarf_entrypc(sp_die, &tmp);
 301                 if (ret || addr != tmp ||
 302                     dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
 303                     dwarf_highpc(sp_die, &tmp))
 304                         return -ENOENT;
 305                 /*
 306                  * This is fuzzed by fentry mcount. We try to find the
 307                  * parameter location at the earliest address.
 308                  */
 309                 for (addr += 1; addr <= tmp; addr++) {
 310                         if (dwarf_getlocation_addr(&attr, addr, &op,
 311                                                    &nops, 1) > 0)
 312                                 goto found;
 313                 }
 314                 return -ENOENT;
 315         }
 316 found:
 317         if (nops == 0)
 318                 /* TODO: Support const_value */
 319                 return -ENOENT;
 320
 321         if (op->atom == DW_OP_addr) {
 322 static_var:
 323                 if (!tvar)
 324                         return 0;
 325                 /* Static variables on memory (not stack), make @varname */
 326                 ret = strlen(dwarf_diename(vr_die));
 327                 tvar->value = zalloc(ret + 2);
 328                 if (tvar->value == NULL)
 329                         return -ENOMEM;
 330                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 331                 tvar->ref = alloc_trace_arg_ref((long)offs);
 332                 if (tvar->ref == NULL)
 333                         return -ENOMEM;
 334                 return 0;
 335         }
 336
 337         /* If this is based on frame buffer, set the offset */
 338         if (op->atom == DW_OP_fbreg) {
 339                 if (fb_ops == NULL)
 340                         return -ENOTSUP;
 341                 ref = true;
 342                 offs = op->number;
 343                 op = &fb_ops[0];
 344         }
 345
 346         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 347                 regn = op->atom - DW_OP_breg0;
 348                 offs += op->number;
 349                 ref = true;
 350         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 351                 regn = op->atom - DW_OP_reg0;
 352         } else if (op->atom == DW_OP_bregx) {
 353                 regn = op->number;
 354                 offs += op->number2;
 355                 ref = true;
 356         } else if (op->atom == DW_OP_regx) {
 357                 regn = op->number;
 358         } else {
 359                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 360                 return -ENOTSUP;
 361         }
 362
 363         if (!tvar)
 364                 return 0;
 365
 366         regs = get_arch_regstr(regn);
 367         if (!regs) {
 368                 /* This should be a bug in DWARF or this tool */
 369                 pr_warning("Mapping for the register number %u "
 370                            "missing on this architecture.\n", regn);
 371                 return -ERANGE;
 372         }
 373
 374         tvar->value = strdup(regs);
 375         if (tvar->value == NULL)
 376                 return -ENOMEM;
 377
 378         if (ref) {
 379                 tvar->ref = alloc_trace_arg_ref((long)offs);
 380                 if (tvar->ref == NULL)
 381                         return -ENOMEM;
 382         }
 383         return 0;
 384 }
 385
 386 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 387
 388 static int convert_variable_type(Dwarf_Die *vr_die,
 389                                  struct probe_trace_arg *tvar,
 390                                  const char *cast)
 391 {
 392         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 393         Dwarf_Die type;
 394         char buf[16];
 395         int bsize, boffs, total;
 396         int ret;
 397
 398         /* TODO: check all types */
 399         if (cast && strcmp(cast, "string") != 0) {
 400                 /* Non string type is OK */
 401                 tvar->type = strdup(cast);
 402                 return (tvar->type == NULL) ? -ENOMEM : 0;
 403         }
 404
 405         bsize = dwarf_bitsize(vr_die);
 406         if (bsize > 0) {
 407                 /* This is a bitfield */
 408                 boffs = dwarf_bitoffset(vr_die);
 409                 total = dwarf_bytesize(vr_die);
 410                 if (boffs < 0 || total < 0)
 411                         return -ENOENT;
 412                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 413                                 BYTES_TO_BITS(total));
 414                 goto formatted;
 415         }
 416
 417         if (die_get_real_type(vr_die, &type) == NULL) {
 418                 pr_warning("Failed to get a type information of %s.\n",
 419                            dwarf_diename(vr_die));
 420                 return -ENOENT;
 421         }
 422
 423         pr_debug("%s type is %s.\n",
 424                  dwarf_diename(vr_die), dwarf_diename(&type));
 425
 426         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 427                 ret = dwarf_tag(&type);
 428                 if (ret != DW_TAG_pointer_type &&
 429                     ret != DW_TAG_array_type) {
 430                         pr_warning("Failed to cast into string: "
 431                                    "%s(%s) is not a pointer nor array.\n",
 432                                    dwarf_diename(vr_die), dwarf_diename(&type));
 433                         return -EINVAL;
 434                 }
 435                 if (die_get_real_type(&type, &type) == NULL) {
 436                         pr_warning("Failed to get a type"
 437                                    " information.\n");
 438                         return -ENOENT;
 439                 }
 440                 if (ret == DW_TAG_pointer_type) {
 441                         while (*ref_ptr)
 442                                 ref_ptr = &(*ref_ptr)->next;
 443                         /* Add new reference with offset +0 */
 444                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 445                         if (*ref_ptr == NULL) {
 446                                 pr_warning("Out of memory error\n");
 447                                 return -ENOMEM;
 448                         }
 449                 }
 450                 if (!die_compare_name(&type, "char") &&
 451                     !die_compare_name(&type, "unsigned char")) {
 452                         pr_warning("Failed to cast into string: "
 453                                    "%s is not (unsigned) char *.\n",
 454                                    dwarf_diename(vr_die));
 455                         return -EINVAL;
 456                 }
 457                 tvar->type = strdup(cast);
 458                 return (tvar->type == NULL) ? -ENOMEM : 0;
 459         }
 460
 461         ret = dwarf_bytesize(&type);
 462         if (ret <= 0)
 463                 /* No size ... try to use default type */
 464                 return 0;
 465         ret = BYTES_TO_BITS(ret);
 466
 467         /* Check the bitwidth */
 468         if (ret > MAX_BASIC_TYPE_BITS) {
 469                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 470                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 471                 ret = MAX_BASIC_TYPE_BITS;
 472         }
 473         ret = snprintf(buf, 16, "%c%d",
 474                        die_is_signed_type(&type) ? 's' : 'u', ret);
 475
 476 formatted:
 477         if (ret < 0 || ret >= 16) {
 478                 if (ret >= 16)
 479                         ret = -E2BIG;
 480                 pr_warning("Failed to convert variable type: %s\n",
 481                            strerror(-ret));
 482                 return ret;
 483         }
 484         tvar->type = strdup(buf);
 485         if (tvar->type == NULL)
 486                 return -ENOMEM;
 487         return 0;
 488 }
 489
 490 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 491                                     struct perf_probe_arg_field *field,
 492                                     struct probe_trace_arg_ref **ref_ptr,
 493                                     Dwarf_Die *die_mem)
 494 {
 495         struct probe_trace_arg_ref *ref = *ref_ptr;
 496         Dwarf_Die type;
 497         Dwarf_Word offs;
 498         int ret, tag;
 499
 500         pr_debug("converting %s in %s\n", field->name, varname);
 501         if (die_get_real_type(vr_die, &type) == NULL) {
 502                 pr_warning("Failed to get the type of %s.\n", varname);
 503                 return -ENOENT;
 504         }
 505         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 506         tag = dwarf_tag(&type);
 507
 508         if (field->name[0] == '[' &&
 509             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 510                 if (field->next)
 511                         /* Save original type for next field */
 512                         memcpy(die_mem, &type, sizeof(*die_mem));
 513                 /* Get the type of this array */
 514                 if (die_get_real_type(&type, &type) == NULL) {
 515                         pr_warning("Failed to get the type of %s.\n", varname);
 516                         return -ENOENT;
 517                 }
 518                 pr_debug2("Array real type: (%x)\n",
 519                          (unsigned)dwarf_dieoffset(&type));
 520                 if (tag == DW_TAG_pointer_type) {
 521                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 522                         if (ref == NULL)
 523                                 return -ENOMEM;
 524                         if (*ref_ptr)
 525                                 (*ref_ptr)->next = ref;
 526                         else
 527                                 *ref_ptr = ref;
 528                 }
 529                 ref->offset += dwarf_bytesize(&type) * field->index;
 530                 if (!field->next)
 531                         /* Save vr_die for converting types */
 532                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 533                 goto next;
 534         } else if (tag == DW_TAG_pointer_type) {
 535                 /* Check the pointer and dereference */
 536                 if (!field->ref) {
 537                         pr_err("Semantic error: %s must be referred by '->'\n",
 538                                field->name);
 539                         return -EINVAL;
 540                 }
 541                 /* Get the type pointed by this pointer */
 542                 if (die_get_real_type(&type, &type) == NULL) {
 543                         pr_warning("Failed to get the type of %s.\n", varname);
 544                         return -ENOENT;
 545                 }
 546                 /* Verify it is a data structure  */
 547                 tag = dwarf_tag(&type);
 548                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 549                         pr_warning("%s is not a data structure nor an union.\n",
 550                                    varname);
 551                         return -EINVAL;
 552                 }
 553
 554                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 555                 if (ref == NULL)
 556                         return -ENOMEM;
 557                 if (*ref_ptr)
 558                         (*ref_ptr)->next = ref;
 559                 else
 560                         *ref_ptr = ref;
 561         } else {
 562                 /* Verify it is a data structure  */
 563                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 564                         pr_warning("%s is not a data structure nor an union.\n",
 565                                    varname);
 566                         return -EINVAL;
 567                 }
 568                 if (field->name[0] == '[') {
 569                         pr_err("Semantic error: %s is not a pointor"
 570                                " nor array.\n", varname);
 571                         return -EINVAL;
 572                 }
 573                 if (field->ref) {
 574                         pr_err("Semantic error: %s must be referred by '.'\n",
 575                                field->name);
 576                         return -EINVAL;
 577                 }
 578                 if (!ref) {
 579                         pr_warning("Structure on a register is not "
 580                                    "supported yet.\n");
 581                         return -ENOTSUP;
 582                 }
 583         }
 584
 585         if (die_find_member(&type, field->name, die_mem) == NULL) {
 586                 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
 587                            dwarf_diename(&type), field->name);
 588                 return -EINVAL;
 589         }
 590
 591         /* Get the offset of the field */
 592         if (tag == DW_TAG_union_type) {
 593                 offs = 0;
 594         } else {
 595                 ret = die_get_data_member_location(die_mem, &offs);
 596                 if (ret < 0) {
 597                         pr_warning("Failed to get the offset of %s.\n",
 598                                    field->name);
 599                         return ret;
 600                 }
 601         }
 602         ref->offset += (long)offs;
 603
 604 next:
 605         /* Converting next field */
 606         if (field->next)
 607                 return convert_variable_fields(die_mem, field->name,
 608                                         field->next, &ref, die_mem);
 609         else
 610                 return 0;
 611 }
 612
 613 /* Show a variables in kprobe event format */
 614 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 615 {
 616         Dwarf_Die die_mem;
 617         int ret;
 618
 619         pr_debug("Converting variable %s into trace event.\n",
 620                  dwarf_diename(vr_die));
 621
 622         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 623                                         &pf->sp_die, pf->tvar);
 624         if (ret == -ENOENT)
 625                 pr_err("Failed to find the location of %s at this address.\n"
 626                        " Perhaps, it has been optimized out.\n", pf->pvar->var);
 627         else if (ret == -ENOTSUP)
 628                 pr_err("Sorry, we don't support this variable location yet.\n");
 629         else if (pf->pvar->field) {
 630                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 631                                               pf->pvar->field, &pf->tvar->ref,
 632                                               &die_mem);
 633                 vr_die = &die_mem;
 634         }
 635         if (ret == 0)
 636                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 637         /* *expr will be cached in libdw. Don't free it. */
 638         return ret;
 639 }
 640
 641 /* Find a variable in a scope DIE */
 642 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 643 {
 644         Dwarf_Die vr_die;
 645         char buf[32], *ptr;
 646         int ret = 0;
 647
 648         if (!is_c_varname(pf->pvar->var)) {
 649                 /* Copy raw parameters */
 650                 pf->tvar->value = strdup(pf->pvar->var);
 651                 if (pf->tvar->value == NULL)
 652                         return -ENOMEM;
 653                 if (pf->pvar->type) {
 654                         pf->tvar->type = strdup(pf->pvar->type);
 655                         if (pf->tvar->type == NULL)
 656                                 return -ENOMEM;
 657                 }
 658                 if (pf->pvar->name) {
 659                         pf->tvar->name = strdup(pf->pvar->name);
 660                         if (pf->tvar->name == NULL)
 661                                 return -ENOMEM;
 662                 } else
 663                         pf->tvar->name = NULL;
 664                 return 0;
 665         }
 666
 667         if (pf->pvar->name)
 668                 pf->tvar->name = strdup(pf->pvar->name);
 669         else {
 670                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 671                 if (ret < 0)
 672                         return ret;
 673                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 674                 if (ptr)
 675                         *ptr = '_';
 676                 pf->tvar->name = strdup(buf);
 677         }
 678         if (pf->tvar->name == NULL)
 679                 return -ENOMEM;
 680
 681         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 682         /* Search child die for local variables and parameters. */
 683         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 684                 /* Search again in global variables */
 685                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
 686                         ret = -ENOENT;
 687         }
 688         if (ret >= 0)
 689                 ret = convert_variable(&vr_die, pf);
 690
 691         if (ret < 0)
 692                 pr_warning("Failed to find '%s' in this function.\n",
 693                            pf->pvar->var);
 694         return ret;
 695 }
 696
 697 /* Convert subprogram DIE to trace point */
 698 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 699                                   Dwarf_Addr paddr, bool retprobe,
 700                                   struct probe_trace_point *tp)
 701 {
 702         Dwarf_Addr eaddr, highaddr;
 703         GElf_Sym sym;
 704         const char *symbol;
 705
 706         /* Verify the address is correct */
 707         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 708                 pr_warning("Failed to get entry address of %s\n",
 709                            dwarf_diename(sp_die));
 710                 return -ENOENT;
 711         }
 712         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 713                 pr_warning("Failed to get end address of %s\n",
 714                            dwarf_diename(sp_die));
 715                 return -ENOENT;
 716         }
 717         if (paddr > highaddr) {
 718                 pr_warning("Offset specified is greater than size of %s\n",
 719                            dwarf_diename(sp_die));
 720                 return -EINVAL;
 721         }
 722
 723         /* Get an appropriate symbol from symtab */
 724         symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 725         if (!symbol) {
 726                 pr_warning("Failed to find symbol at 0x%lx\n",
 727                            (unsigned long)paddr);
 728                 return -ENOENT;
 729         }
 730         tp->offset = (unsigned long)(paddr - sym.st_value);
 731         tp->symbol = strdup(symbol);
 732         if (!tp->symbol)
 733                 return -ENOMEM;
 734
 735         /* Return probe must be on the head of a subprogram */
 736         if (retprobe) {
 737                 if (eaddr != paddr) {
 738                         pr_warning("Return probe must be on the head of"
 739                                    " a real function.\n");
 740                         return -EINVAL;
 741                 }
 742                 tp->retprobe = true;
 743         }
 744
 745         return 0;
 746 }
 747
 748 /* Call probe_finder callback with scope DIE */
 749 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 750 {
 751         Dwarf_Attribute fb_attr;
 752         size_t nops;
 753         int ret;
 754
 755         if (!sc_die) {
 756                 pr_err("Caller must pass a scope DIE. Program error.\n");
 757                 return -EINVAL;
 758         }
 759
 760         /* If not a real subprogram, find a real one */
 761         if (!die_is_func_def(sc_die)) {
 762                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 763                         pr_warning("Failed to find probe point in any "
 764                                    "functions.\n");
 765                         return -ENOENT;
 766                 }
 767         } else
 768                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 769
 770         /* Get the frame base attribute/ops from subprogram */
 771         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 772         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 773         if (ret <= 0 || nops == 0) {
 774                 pf->fb_ops = NULL;
 775 #if _ELFUTILS_PREREQ(0, 142)
 776         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 777                    pf->cfi != NULL) {
 778                 Dwarf_Frame *frame;
 779                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 780                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 781                         pr_warning("Failed to get call frame on 0x%jx\n",
 782                                    (uintmax_t)pf->addr);
 783                         return -ENOENT;
 784                 }
 785 #endif
 786         }
 787
 788         /* Call finder's callback handler */
 789         ret = pf->callback(sc_die, pf);
 790
 791         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 792         pf->fb_ops = NULL;
 793
 794         return ret;
 795 }
 796
 797 struct find_scope_param {
 798         const char *function;
 799         const char *file;
 800         int line;
 801         int diff;
 802         Dwarf_Die *die_mem;
 803         bool found;
 804 };
 805
 806 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 807 {
 808         struct find_scope_param *fsp = data;
 809         const char *file;
 810         int lno;
 811
 812         /* Skip if declared file name does not match */
 813         if (fsp->file) {
 814                 file = dwarf_decl_file(fn_die);
 815                 if (!file || strcmp(fsp->file, file) != 0)
 816                         return 0;
 817         }
 818         /* If the function name is given, that's what user expects */
 819         if (fsp->function) {
 820                 if (die_compare_name(fn_die, fsp->function)) {
 821                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 822                         fsp->found = true;
 823                         return 1;
 824                 }
 825         } else {
 826                 /* With the line number, find the nearest declared DIE */
 827                 dwarf_decl_line(fn_die, &lno);
 828                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 829                         /* Keep a candidate and continue */
 830                         fsp->diff = fsp->line - lno;
 831                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 832                         fsp->found = true;
 833                 }
 834         }
 835         return 0;
 836 }
 837
 838 /* Find an appropriate scope fits to given conditions */
 839 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 840 {
 841         struct find_scope_param fsp = {
 842                 .function = pf->pev->point.function,
 843                 .file = pf->fname,
 844                 .line = pf->lno,
 845                 .diff = INT_MAX,
 846                 .die_mem = die_mem,
 847                 .found = false,
 848         };
 849
 850         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 851
 852         return fsp.found ? die_mem : NULL;
 853 }
 854
 855 static int probe_point_line_walker(const char *fname, int lineno,
 856                                    Dwarf_Addr addr, void *data)
 857 {
 858         struct probe_finder *pf = data;
 859         Dwarf_Die *sc_die, die_mem;
 860         int ret;
 861
 862         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 863                 return 0;
 864
 865         pf->addr = addr;
 866         sc_die = find_best_scope(pf, &die_mem);
 867         if (!sc_die) {
 868                 pr_warning("Failed to find scope of probe point.\n");
 869                 return -ENOENT;
 870         }
 871
 872         ret = call_probe_finder(sc_die, pf);
 873
 874         /* Continue if no error, because the line will be in inline function */
 875         return ret < 0 ? ret : 0;
 876 }
 877
 878 /* Find probe point from its line number */
 879 static int find_probe_point_by_line(struct probe_finder *pf)
 880 {
 881         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 882 }
 883
 884 /* Find lines which match lazy pattern */
 885 static int find_lazy_match_lines(struct list_head *head,
 886                                  const char *fname, const char *pat)
 887 {
 888         FILE *fp;
 889         char *line = NULL;
 890         size_t line_len;
 891         ssize_t len;
 892         int count = 0, linenum = 1;
 893
 894         fp = fopen(fname, "r");
 895         if (!fp) {
 896                 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
 897                 return -errno;
 898         }
 899
 900         while ((len = getline(&line, &line_len, fp)) > 0) {
 901
 902                 if (line[len - 1] == '\n')
 903                         line[len - 1] = '\0';
 904
 905                 if (strlazymatch(line, pat)) {
 906                         line_list__add_line(head, linenum);
 907                         count++;
 908                 }
 909                 linenum++;
 910         }
 911
 912         if (ferror(fp))
 913                 count = -errno;
 914         free(line);
 915         fclose(fp);
 916
 917         if (count == 0)
 918                 pr_debug("No matched lines found in %s.\n", fname);
 919         return count;
 920 }
 921
 922 static int probe_point_lazy_walker(const char *fname, int lineno,
 923                                    Dwarf_Addr addr, void *data)
 924 {
 925         struct probe_finder *pf = data;
 926         Dwarf_Die *sc_die, die_mem;
 927         int ret;
 928
 929         if (!line_list__has_line(&pf->lcache, lineno) ||
 930             strtailcmp(fname, pf->fname) != 0)
 931                 return 0;
 932
 933         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 934                  lineno, (unsigned long long)addr);
 935         pf->addr = addr;
 936         pf->lno = lineno;
 937         sc_die = find_best_scope(pf, &die_mem);
 938         if (!sc_die) {
 939                 pr_warning("Failed to find scope of probe point.\n");
 940                 return -ENOENT;
 941         }
 942
 943         ret = call_probe_finder(sc_die, pf);
 944
 945         /*
 946          * Continue if no error, because the lazy pattern will match
 947          * to other lines
 948          */
 949         return ret < 0 ? ret : 0;
 950 }
 951
 952 /* Find probe points from lazy pattern  */
 953 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 954 {
 955         int ret = 0;
 956
 957         if (list_empty(&pf->lcache)) {
 958                 /* Matching lazy line pattern */
 959                 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
 960                                             pf->pev->point.lazy_line);
 961                 if (ret <= 0)
 962                         return ret;
 963         }
 964
 965         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 966 }
 967
 968 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 969 {
 970         struct probe_finder *pf = data;
 971         struct perf_probe_point *pp = &pf->pev->point;
 972         Dwarf_Addr addr;
 973         int ret;
 974
 975         if (pp->lazy_line)
 976                 ret = find_probe_point_lazy(in_die, pf);
 977         else {
 978                 /* Get probe address */
 979                 if (dwarf_entrypc(in_die, &addr) != 0) {
 980                         pr_warning("Failed to get entry address of %s.\n",
 981                                    dwarf_diename(in_die));
 982                         return -ENOENT;
 983                 }
 984                 pf->addr = addr;
 985                 pf->addr += pp->offset;
 986                 pr_debug("found inline addr: 0x%jx\n",
 987                          (uintmax_t)pf->addr);
 988
 989                 ret = call_probe_finder(in_die, pf);
 990         }
 991
 992         return ret;
 993 }
 994
 995 /* Callback parameter with return value for libdw */
 996 struct dwarf_callback_param {
 997         void *data;
 998         int retval;
 999 };
1000
1001 /* Search function from function name */
1002 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1003 {
1004         struct dwarf_callback_param *param = data;
1005         struct probe_finder *pf = param->data;
1006         struct perf_probe_point *pp = &pf->pev->point;
1007
1008         /* Check tag and diename */
1009         if (!die_is_func_def(sp_die) ||
1010             !die_compare_name(sp_die, pp->function))
1011                 return DWARF_CB_OK;
1012
1013         /* Check declared file */
1014         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1015                 return DWARF_CB_OK;
1016
1017         pf->fname = dwarf_decl_file(sp_die);
1018         if (pp->line) { /* Function relative line */
1019                 dwarf_decl_line(sp_die, &pf->lno);
1020                 pf->lno += pp->line;
1021                 param->retval = find_probe_point_by_line(pf);
1022         } else if (!dwarf_func_inline(sp_die)) {
1023                 /* Real function */
1024                 if (pp->lazy_line)
1025                         param->retval = find_probe_point_lazy(sp_die, pf);
1026                 else {
1027                         if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1028                                 pr_warning("Failed to get entry address of "
1029                                            "%s.\n", dwarf_diename(sp_die));
1030                                 param->retval = -ENOENT;
1031                                 return DWARF_CB_ABORT;
1032                         }
1033                         pf->addr += pp->offset;
1034                         /* TODO: Check the address in this function */
1035                         param->retval = call_probe_finder(sp_die, pf);
1036                 }
1037         } else
1038                 /* Inlined function: search instances */
1039                 param->retval = die_walk_instances(sp_die,
1040                                         probe_point_inline_cb, (void *)pf);
1041
1042         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1043 }
1044
1045 static int find_probe_point_by_func(struct probe_finder *pf)
1046 {
1047         struct dwarf_callback_param _param = {.data = (void *)pf,
1048                                               .retval = 0};
1049         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1050         return _param.retval;
1051 }
1052
1053 struct pubname_callback_param {
1054         char *function;
1055         char *file;
1056         Dwarf_Die *cu_die;
1057         Dwarf_Die *sp_die;
1058         int found;
1059 };
1060
1061 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1062 {
1063         struct pubname_callback_param *param = data;
1064
1065         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1066                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1067                         return DWARF_CB_OK;
1068
1069                 if (die_compare_name(param->sp_die, param->function)) {
1070                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1071                                 return DWARF_CB_OK;
1072
1073                         if (param->file &&
1074                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1075                                 return DWARF_CB_OK;
1076
1077                         param->found = 1;
1078                         return DWARF_CB_ABORT;
1079                 }
1080         }
1081
1082         return DWARF_CB_OK;
1083 }
1084
1085 /* Find probe points from debuginfo */
1086 static int debuginfo__find_probes(struct debuginfo *self,
1087                                   struct probe_finder *pf)
1088 {
1089         struct perf_probe_point *pp = &pf->pev->point;
1090         Dwarf_Off off, noff;
1091         size_t cuhl;
1092         Dwarf_Die *diep;
1093         int ret = 0;
1094
1095 #if _ELFUTILS_PREREQ(0, 142)
1096         /* Get the call frame information from this dwarf */
1097         pf->cfi = dwarf_getcfi(self->dbg);
1098 #endif
1099
1100         off = 0;
1101         line_list__init(&pf->lcache);
1102
1103         /* Fastpath: lookup by function name from .debug_pubnames section */
1104         if (pp->function) {
1105                 struct pubname_callback_param pubname_param = {
1106                         .function = pp->function,
1107                         .file     = pp->file,
1108                         .cu_die   = &pf->cu_die,
1109                         .sp_die   = &pf->sp_die,
1110                         .found    = 0,
1111                 };
1112                 struct dwarf_callback_param probe_param = {
1113                         .data = pf,
1114                 };
1115
1116                 dwarf_getpubnames(self->dbg, pubname_search_cb,
1117                                   &pubname_param, 0);
1118                 if (pubname_param.found) {
1119                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1120                         if (ret)
1121                                 goto found;
1122                 }
1123         }
1124
1125         /* Loop on CUs (Compilation Unit) */
1126         while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1127                 /* Get the DIE(Debugging Information Entry) of this CU */
1128                 diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die);
1129                 if (!diep)
1130                         continue;
1131
1132                 /* Check if target file is included. */
1133                 if (pp->file)
1134                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1135                 else
1136                         pf->fname = NULL;
1137
1138                 if (!pp->file || pf->fname) {
1139                         if (pp->function)
1140                                 ret = find_probe_point_by_func(pf);
1141                         else if (pp->lazy_line)
1142                                 ret = find_probe_point_lazy(NULL, pf);
1143                         else {
1144                                 pf->lno = pp->line;
1145                                 ret = find_probe_point_by_line(pf);
1146                         }
1147                         if (ret < 0)
1148                                 break;
1149                 }
1150                 off = noff;
1151         }
1152
1153 found:
1154         line_list__free(&pf->lcache);
1155
1156         return ret;
1157 }
1158
1159 struct local_vars_finder {
1160         struct probe_finder *pf;
1161         struct perf_probe_arg *args;
1162         int max_args;
1163         int nargs;
1164         int ret;
1165 };
1166
1167 /* Collect available variables in this scope */
1168 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1169 {
1170         struct local_vars_finder *vf = data;
1171         struct probe_finder *pf = vf->pf;
1172         int tag;
1173
1174         tag = dwarf_tag(die_mem);
1175         if (tag == DW_TAG_formal_parameter ||
1176             tag == DW_TAG_variable) {
1177                 if (convert_variable_location(die_mem, vf->pf->addr,
1178                                               vf->pf->fb_ops, &pf->sp_die,
1179                                               NULL) == 0) {
1180                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1181                         if (vf->args[vf->nargs].var == NULL) {
1182                                 vf->ret = -ENOMEM;
1183                                 return DIE_FIND_CB_END;
1184                         }
1185                         pr_debug(" %s", vf->args[vf->nargs].var);
1186                         vf->nargs++;
1187                 }
1188         }
1189
1190         if (dwarf_haspc(die_mem, vf->pf->addr))
1191                 return DIE_FIND_CB_CONTINUE;
1192         else
1193                 return DIE_FIND_CB_SIBLING;
1194 }
1195
1196 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1197                              struct perf_probe_arg *args)
1198 {
1199         Dwarf_Die die_mem;
1200         int i;
1201         int n = 0;
1202         struct local_vars_finder vf = {.pf = pf, .args = args,
1203                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1204
1205         for (i = 0; i < pf->pev->nargs; i++) {
1206                 /* var never be NULL */
1207                 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1208                         pr_debug("Expanding $vars into:");
1209                         vf.nargs = n;
1210                         /* Special local variables */
1211                         die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1212                                        &die_mem);
1213                         pr_debug(" (%d)\n", vf.nargs - n);
1214                         if (vf.ret < 0)
1215                                 return vf.ret;
1216                         n = vf.nargs;
1217                 } else {
1218                         /* Copy normal argument */
1219                         args[n] = pf->pev->args[i];
1220                         n++;
1221                 }
1222         }
1223         return n;
1224 }
1225
1226 /* Add a found probe point into trace event list */
1227 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1228 {
1229         struct trace_event_finder *tf =
1230                         container_of(pf, struct trace_event_finder, pf);
1231         struct probe_trace_event *tev;
1232         struct perf_probe_arg *args;
1233         int ret, i;
1234
1235         /* Check number of tevs */
1236         if (tf->ntevs == tf->max_tevs) {
1237                 pr_warning("Too many( > %d) probe point found.\n",
1238                            tf->max_tevs);
1239                 return -ERANGE;
1240         }
1241         tev = &tf->tevs[tf->ntevs++];
1242
1243         /* Trace point should be converted from subprogram DIE */
1244         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1245                                      pf->pev->point.retprobe, &tev->point);
1246         if (ret < 0)
1247                 return ret;
1248
1249         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1250                  tev->point.offset);
1251
1252         /* Expand special probe argument if exist */
1253         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1254         if (args == NULL)
1255                 return -ENOMEM;
1256
1257         ret = expand_probe_args(sc_die, pf, args);
1258         if (ret < 0)
1259                 goto end;
1260
1261         tev->nargs = ret;
1262         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1263         if (tev->args == NULL) {
1264                 ret = -ENOMEM;
1265                 goto end;
1266         }
1267
1268         /* Find each argument */
1269         for (i = 0; i < tev->nargs; i++) {
1270                 pf->pvar = &args[i];
1271                 pf->tvar = &tev->args[i];
1272                 /* Variable should be found from scope DIE */
1273                 ret = find_variable(sc_die, pf);
1274                 if (ret != 0)
1275                         break;
1276         }
1277
1278 end:
1279         free(args);
1280         return ret;
1281 }
1282
1283 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1284 int debuginfo__find_trace_events(struct debuginfo *self,
1285                                  struct perf_probe_event *pev,
1286                                  struct probe_trace_event **tevs, int max_tevs)
1287 {
1288         struct trace_event_finder tf = {
1289                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1290                         .mod = self->mod, .max_tevs = max_tevs};
1291         int ret;
1292
1293         /* Allocate result tevs array */
1294         *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1295         if (*tevs == NULL)
1296                 return -ENOMEM;
1297
1298         tf.tevs = *tevs;
1299         tf.ntevs = 0;
1300
1301         ret = debuginfo__find_probes(self, &tf.pf);
1302         if (ret < 0) {
1303                 free(*tevs);
1304                 *tevs = NULL;
1305                 return ret;
1306         }
1307
1308         return (ret < 0) ? ret : tf.ntevs;
1309 }
1310
1311 #define MAX_VAR_LEN 64
1312
1313 /* Collect available variables in this scope */
1314 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1315 {
1316         struct available_var_finder *af = data;
1317         struct variable_list *vl;
1318         char buf[MAX_VAR_LEN];
1319         int tag, ret;
1320
1321         vl = &af->vls[af->nvls - 1];
1322
1323         tag = dwarf_tag(die_mem);
1324         if (tag == DW_TAG_formal_parameter ||
1325             tag == DW_TAG_variable) {
1326                 ret = convert_variable_location(die_mem, af->pf.addr,
1327                                                 af->pf.fb_ops, &af->pf.sp_die,
1328                                                 NULL);
1329                 if (ret == 0) {
1330                         ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1331                         pr_debug2("Add new var: %s\n", buf);
1332                         if (ret > 0)
1333                                 strlist__add(vl->vars, 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 /* Add a found vars into available variables list */
1344 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1345 {
1346         struct available_var_finder *af =
1347                         container_of(pf, struct available_var_finder, pf);
1348         struct variable_list *vl;
1349         Dwarf_Die die_mem;
1350         int ret;
1351
1352         /* Check number of tevs */
1353         if (af->nvls == af->max_vls) {
1354                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1355                 return -ERANGE;
1356         }
1357         vl = &af->vls[af->nvls++];
1358
1359         /* Trace point should be converted from subprogram DIE */
1360         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1361                                      pf->pev->point.retprobe, &vl->point);
1362         if (ret < 0)
1363                 return ret;
1364
1365         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1366                  vl->point.offset);
1367
1368         /* Find local variables */
1369         vl->vars = strlist__new(true, NULL);
1370         if (vl->vars == NULL)
1371                 return -ENOMEM;
1372         af->child = true;
1373         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1374
1375         /* Find external variables */
1376         if (!af->externs)
1377                 goto out;
1378         /* Don't need to search child DIE for externs. */
1379         af->child = false;
1380         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1381
1382 out:
1383         if (strlist__empty(vl->vars)) {
1384                 strlist__delete(vl->vars);
1385                 vl->vars = NULL;
1386         }
1387
1388         return ret;
1389 }
1390
1391 /* Find available variables at given probe point */
1392 int debuginfo__find_available_vars_at(struct debuginfo *self,
1393                                       struct perf_probe_event *pev,
1394                                       struct variable_list **vls,
1395                                       int max_vls, bool externs)
1396 {
1397         struct available_var_finder af = {
1398                         .pf = {.pev = pev, .callback = add_available_vars},
1399                         .mod = self->mod,
1400                         .max_vls = max_vls, .externs = externs};
1401         int ret;
1402
1403         /* Allocate result vls array */
1404         *vls = zalloc(sizeof(struct variable_list) * max_vls);
1405         if (*vls == NULL)
1406                 return -ENOMEM;
1407
1408         af.vls = *vls;
1409         af.nvls = 0;
1410
1411         ret = debuginfo__find_probes(self, &af.pf);
1412         if (ret < 0) {
1413                 /* Free vlist for error */
1414                 while (af.nvls--) {
1415                         if (af.vls[af.nvls].point.symbol)
1416                                 free(af.vls[af.nvls].point.symbol);
1417                         if (af.vls[af.nvls].vars)
1418                                 strlist__delete(af.vls[af.nvls].vars);
1419                 }
1420                 free(af.vls);
1421                 *vls = NULL;
1422                 return ret;
1423         }
1424
1425         return (ret < 0) ? ret : af.nvls;
1426 }
1427
1428 /* Reverse search */
1429 int debuginfo__find_probe_point(struct debuginfo *self, unsigned long addr,
1430                                 struct perf_probe_point *ppt)
1431 {
1432         Dwarf_Die cudie, spdie, indie;
1433         Dwarf_Addr _addr = 0, baseaddr = 0;
1434         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1435         int baseline = 0, lineno = 0, ret = 0;
1436
1437         /* Adjust address with bias */
1438         addr += self->bias;
1439
1440         /* Find cu die */
1441         if (!dwarf_addrdie(self->dbg, (Dwarf_Addr)addr - self->bias, &cudie)) {
1442                 pr_warning("Failed to find debug information for address %lx\n",
1443                            addr);
1444                 ret = -EINVAL;
1445                 goto end;
1446         }
1447
1448         /* Find a corresponding line (filename and lineno) */
1449         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1450         /* Don't care whether it failed or not */
1451
1452         /* Find a corresponding function (name, baseline and baseaddr) */
1453         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1454                 /* Get function entry information */
1455                 func = basefunc = dwarf_diename(&spdie);
1456                 if (!func ||
1457                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1458                     dwarf_decl_line(&spdie, &baseline) != 0) {
1459                         lineno = 0;
1460                         goto post;
1461                 }
1462
1463                 fname = dwarf_decl_file(&spdie);
1464                 if (addr == (unsigned long)baseaddr) {
1465                         /* Function entry - Relative line number is 0 */
1466                         lineno = baseline;
1467                         goto post;
1468                 }
1469
1470                 /* Track down the inline functions step by step */
1471                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1472                                                 &indie)) {
1473                         /* There is an inline function */
1474                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1475                             _addr == addr) {
1476                                 /*
1477                                  * addr is at an inline function entry.
1478                                  * In this case, lineno should be the call-site
1479                                  * line number. (overwrite lineinfo)
1480                                  */
1481                                 lineno = die_get_call_lineno(&indie);
1482                                 fname = die_get_call_file(&indie);
1483                                 break;
1484                         } else {
1485                                 /*
1486                                  * addr is in an inline function body.
1487                                  * Since lineno points one of the lines
1488                                  * of the inline function, baseline should
1489                                  * be the entry line of the inline function.
1490                                  */
1491                                 tmp = dwarf_diename(&indie);
1492                                 if (!tmp ||
1493                                     dwarf_decl_line(&indie, &baseline) != 0)
1494                                         break;
1495                                 func = tmp;
1496                                 spdie = indie;
1497                         }
1498                 }
1499                 /* Verify the lineno and baseline are in a same file */
1500                 tmp = dwarf_decl_file(&spdie);
1501                 if (!tmp || strcmp(tmp, fname) != 0)
1502                         lineno = 0;
1503         }
1504
1505 post:
1506         /* Make a relative line number or an offset */
1507         if (lineno)
1508                 ppt->line = lineno - baseline;
1509         else if (basefunc) {
1510                 ppt->offset = addr - (unsigned long)baseaddr;
1511                 func = basefunc;
1512         }
1513
1514         /* Duplicate strings */
1515         if (func) {
1516                 ppt->function = strdup(func);
1517                 if (ppt->function == NULL) {
1518                         ret = -ENOMEM;
1519                         goto end;
1520                 }
1521         }
1522         if (fname) {
1523                 ppt->file = strdup(fname);
1524                 if (ppt->file == NULL) {
1525                         if (ppt->function) {
1526                                 free(ppt->function);
1527                                 ppt->function = NULL;
1528                         }
1529                         ret = -ENOMEM;
1530                         goto end;
1531                 }
1532         }
1533 end:
1534         if (ret == 0 && (fname || func))
1535                 ret = 1;        /* Found a point */
1536         return ret;
1537 }
1538
1539 /* Add a line and store the src path */
1540 static int line_range_add_line(const char *src, unsigned int lineno,
1541                                struct line_range *lr)
1542 {
1543         /* Copy source path */
1544         if (!lr->path) {
1545                 lr->path = strdup(src);
1546                 if (lr->path == NULL)
1547                         return -ENOMEM;
1548         }
1549         return line_list__add_line(&lr->line_list, lineno);
1550 }
1551
1552 static int line_range_walk_cb(const char *fname, int lineno,
1553                               Dwarf_Addr addr __maybe_unused,
1554                               void *data)
1555 {
1556         struct line_finder *lf = data;
1557
1558         if ((strtailcmp(fname, lf->fname) != 0) ||
1559             (lf->lno_s > lineno || lf->lno_e < lineno))
1560                 return 0;
1561
1562         if (line_range_add_line(fname, lineno, lf->lr) < 0)
1563                 return -EINVAL;
1564
1565         return 0;
1566 }
1567
1568 /* Find line range from its line number */
1569 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1570 {
1571         int ret;
1572
1573         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1574
1575         /* Update status */
1576         if (ret >= 0)
1577                 if (!list_empty(&lf->lr->line_list))
1578                         ret = lf->found = 1;
1579                 else
1580                         ret = 0;        /* Lines are not found */
1581         else {
1582                 free(lf->lr->path);
1583                 lf->lr->path = NULL;
1584         }
1585         return ret;
1586 }
1587
1588 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1589 {
1590         find_line_range_by_line(in_die, data);
1591
1592         /*
1593          * We have to check all instances of inlined function, because
1594          * some execution paths can be optimized out depends on the
1595          * function argument of instances
1596          */
1597         return 0;
1598 }
1599
1600 /* Search function definition from function name */
1601 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1602 {
1603         struct dwarf_callback_param *param = data;
1604         struct line_finder *lf = param->data;
1605         struct line_range *lr = lf->lr;
1606
1607         /* Check declared file */
1608         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1609                 return DWARF_CB_OK;
1610
1611         if (die_is_func_def(sp_die) &&
1612             die_compare_name(sp_die, lr->function)) {
1613                 lf->fname = dwarf_decl_file(sp_die);
1614                 dwarf_decl_line(sp_die, &lr->offset);
1615                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1616                 lf->lno_s = lr->offset + lr->start;
1617                 if (lf->lno_s < 0)      /* Overflow */
1618                         lf->lno_s = INT_MAX;
1619                 lf->lno_e = lr->offset + lr->end;
1620                 if (lf->lno_e < 0)      /* Overflow */
1621                         lf->lno_e = INT_MAX;
1622                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1623                 lr->start = lf->lno_s;
1624                 lr->end = lf->lno_e;
1625                 if (dwarf_func_inline(sp_die))
1626                         param->retval = die_walk_instances(sp_die,
1627                                                 line_range_inline_cb, lf);
1628                 else
1629                         param->retval = find_line_range_by_line(sp_die, lf);
1630                 return DWARF_CB_ABORT;
1631         }
1632         return DWARF_CB_OK;
1633 }
1634
1635 static int find_line_range_by_func(struct line_finder *lf)
1636 {
1637         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1638         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1639         return param.retval;
1640 }
1641
1642 int debuginfo__find_line_range(struct debuginfo *self, struct line_range *lr)
1643 {
1644         struct line_finder lf = {.lr = lr, .found = 0};
1645         int ret = 0;
1646         Dwarf_Off off = 0, noff;
1647         size_t cuhl;
1648         Dwarf_Die *diep;
1649         const char *comp_dir;
1650
1651         /* Fastpath: lookup by function name from .debug_pubnames section */
1652         if (lr->function) {
1653                 struct pubname_callback_param pubname_param = {
1654                         .function = lr->function, .file = lr->file,
1655                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1656                 struct dwarf_callback_param line_range_param = {
1657                         .data = (void *)&lf, .retval = 0};
1658
1659                 dwarf_getpubnames(self->dbg, pubname_search_cb,
1660                                   &pubname_param, 0);
1661                 if (pubname_param.found) {
1662                         line_range_search_cb(&lf.sp_die, &line_range_param);
1663                         if (lf.found)
1664                                 goto found;
1665                 }
1666         }
1667
1668         /* Loop on CUs (Compilation Unit) */
1669         while (!lf.found && ret >= 0) {
1670                 if (dwarf_nextcu(self->dbg, off, &noff, &cuhl,
1671                                  NULL, NULL, NULL) != 0)
1672                         break;
1673
1674                 /* Get the DIE(Debugging Information Entry) of this CU */
1675                 diep = dwarf_offdie(self->dbg, off + cuhl, &lf.cu_die);
1676                 if (!diep)
1677                         continue;
1678
1679                 /* Check if target file is included. */
1680                 if (lr->file)
1681                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1682                 else
1683                         lf.fname = 0;
1684
1685                 if (!lr->file || lf.fname) {
1686                         if (lr->function)
1687                                 ret = find_line_range_by_func(&lf);
1688                         else {
1689                                 lf.lno_s = lr->start;
1690                                 lf.lno_e = lr->end;
1691                                 ret = find_line_range_by_line(NULL, &lf);
1692                         }
1693                 }
1694                 off = noff;
1695         }
1696
1697 found:
1698         /* Store comp_dir */
1699         if (lf.found) {
1700                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1701                 if (comp_dir) {
1702                         lr->comp_dir = strdup(comp_dir);
1703                         if (!lr->comp_dir)
1704                                 ret = -ENOMEM;
1705                 }
1706         }
1707
1708         pr_debug("path: %s\n", lr->path);
1709         return (ret < 0) ? ret : lf.found;
1710 }
1711