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