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 "intlist.h"
  39 #include "util.h"
  40 #include "symbol.h"
  41 #include "probe-finder.h"
  42
  43 /* Kprobe tracer basic type is up to u64 */
  44 #define MAX_BASIC_TYPE_BITS     64
  45
  46 /* Dwarf FL wrappers */
  47 static char *debuginfo_path;    /* Currently dummy */
  48
  49 static const Dwfl_Callbacks offline_callbacks = {
  50         .find_debuginfo = dwfl_standard_find_debuginfo,
  51         .debuginfo_path = &debuginfo_path,
  52
  53         .section_address = dwfl_offline_section_address,
  54
  55         /* We use this table for core files too.  */
  56         .find_elf = dwfl_build_id_find_elf,
  57 };
  58
  59 /* Get a Dwarf from offline image */
  60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  61                                          const char *path)
  62 {
  63         int fd;
  64
  65         fd = open(path, O_RDONLY);
  66         if (fd < 0)
  67                 return fd;
  68
  69         dbg->dwfl = dwfl_begin(&offline_callbacks);
  70         if (!dbg->dwfl)
  71                 goto error;
  72
  73         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  74         if (!dbg->mod)
  75                 goto error;
  76
  77         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  78         if (!dbg->dbg)
  79                 goto error;
  80
  81         return 0;
  82 error:
  83         if (dbg->dwfl)
  84                 dwfl_end(dbg->dwfl);
  85         else
  86                 close(fd);
  87         memset(dbg, 0, sizeof(*dbg));
  88
  89         return -ENOENT;
  90 }
  91
  92 #if _ELFUTILS_PREREQ(0, 148)
  93 /* This method is buggy if elfutils is older than 0.148 */
  94 static int __linux_kernel_find_elf(Dwfl_Module *mod,
  95                                    void **userdata,
  96                                    const char *module_name,
  97                                    Dwarf_Addr base,
  98                                    char **file_name, Elf **elfp)
  99 {
 100         int fd;
 101         const char *path = kernel_get_module_path(module_name);
 102
 103         pr_debug2("Use file %s for %s\n", path, module_name);
 104         if (path) {
 105                 fd = open(path, O_RDONLY);
 106                 if (fd >= 0) {
 107                         *file_name = strdup(path);
 108                         return fd;
 109                 }
 110         }
 111         /* If failed, try to call standard method */
 112         return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
 113                                           file_name, elfp);
 114 }
 115
 116 static const Dwfl_Callbacks kernel_callbacks = {
 117         .find_debuginfo = dwfl_standard_find_debuginfo,
 118         .debuginfo_path = &debuginfo_path,
 119
 120         .find_elf = __linux_kernel_find_elf,
 121         .section_address = dwfl_linux_kernel_module_section_address,
 122 };
 123
 124 /* Get a Dwarf from live kernel image */
 125 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg,
 126                                                Dwarf_Addr addr)
 127 {
 128         dbg->dwfl = dwfl_begin(&kernel_callbacks);
 129         if (!dbg->dwfl)
 130                 return -EINVAL;
 131
 132         /* Load the kernel dwarves: Don't care the result here */
 133         dwfl_linux_kernel_report_kernel(dbg->dwfl);
 134         dwfl_linux_kernel_report_modules(dbg->dwfl);
 135
 136         dbg->dbg = dwfl_addrdwarf(dbg->dwfl, addr, &dbg->bias);
 137         /* Here, check whether we could get a real dwarf */
 138         if (!dbg->dbg) {
 139                 pr_debug("Failed to find kernel dwarf at %lx\n",
 140                          (unsigned long)addr);
 141                 dwfl_end(dbg->dwfl);
 142                 memset(dbg, 0, sizeof(*dbg));
 143                 return -ENOENT;
 144         }
 145
 146         return 0;
 147 }
 148 #else
 149 /* With older elfutils, this just support kernel module... */
 150 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg,
 151                                                Dwarf_Addr addr __maybe_unused)
 152 {
 153         const char *path = kernel_get_module_path("kernel");
 154
 155         if (!path) {
 156                 pr_err("Failed to find vmlinux path\n");
 157                 return -ENOENT;
 158         }
 159
 160         pr_debug2("Use file %s for debuginfo\n", path);
 161         return debuginfo__init_offline_dwarf(dbg, path);
 162 }
 163 #endif
 164
 165 struct debuginfo *debuginfo__new(const char *path)
 166 {
 167         struct debuginfo *dbg = zalloc(sizeof(*dbg));
 168         if (!dbg)
 169                 return NULL;
 170
 171         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 172                 zfree(&dbg);
 173
 174         return dbg;
 175 }
 176
 177 struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
 178 {
 179         struct debuginfo *dbg = zalloc(sizeof(*dbg));
 180
 181         if (!dbg)
 182                 return NULL;
 183
 184         if (debuginfo__init_online_kernel_dwarf(dbg, (Dwarf_Addr)addr) < 0)
 185                 zfree(&dbg);
 186
 187         return dbg;
 188 }
 189
 190 void debuginfo__delete(struct debuginfo *dbg)
 191 {
 192         if (dbg) {
 193                 if (dbg->dwfl)
 194                         dwfl_end(dbg->dwfl);
 195                 free(dbg);
 196         }
 197 }
 198
 199 /*
 200  * Probe finder related functions
 201  */
 202
 203 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 204 {
 205         struct probe_trace_arg_ref *ref;
 206         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 207         if (ref != NULL)
 208                 ref->offset = offs;
 209         return ref;
 210 }
 211
 212 /*
 213  * Convert a location into trace_arg.
 214  * If tvar == NULL, this just checks variable can be converted.
 215  * If fentry == true and vr_die is a parameter, do huristic search
 216  * for the location fuzzed by function entry mcount.
 217  */
 218 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 219                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 220                                      struct probe_trace_arg *tvar)
 221 {
 222         Dwarf_Attribute attr;
 223         Dwarf_Addr tmp = 0;
 224         Dwarf_Op *op;
 225         size_t nops;
 226         unsigned int regn;
 227         Dwarf_Word offs = 0;
 228         bool ref = false;
 229         const char *regs;
 230         int ret;
 231
 232         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 233                 goto static_var;
 234
 235         /* TODO: handle more than 1 exprs */
 236         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 237                 return -EINVAL; /* Broken DIE ? */
 238         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 239                 ret = dwarf_entrypc(sp_die, &tmp);
 240                 if (ret || addr != tmp ||
 241                     dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
 242                     dwarf_highpc(sp_die, &tmp))
 243                         return -ENOENT;
 244                 /*
 245                  * This is fuzzed by fentry mcount. We try to find the
 246                  * parameter location at the earliest address.
 247                  */
 248                 for (addr += 1; addr <= tmp; addr++) {
 249                         if (dwarf_getlocation_addr(&attr, addr, &op,
 250                                                    &nops, 1) > 0)
 251                                 goto found;
 252                 }
 253                 return -ENOENT;
 254         }
 255 found:
 256         if (nops == 0)
 257                 /* TODO: Support const_value */
 258                 return -ENOENT;
 259
 260         if (op->atom == DW_OP_addr) {
 261 static_var:
 262                 if (!tvar)
 263                         return 0;
 264                 /* Static variables on memory (not stack), make @varname */
 265                 ret = strlen(dwarf_diename(vr_die));
 266                 tvar->value = zalloc(ret + 2);
 267                 if (tvar->value == NULL)
 268                         return -ENOMEM;
 269                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 270                 tvar->ref = alloc_trace_arg_ref((long)offs);
 271                 if (tvar->ref == NULL)
 272                         return -ENOMEM;
 273                 return 0;
 274         }
 275
 276         /* If this is based on frame buffer, set the offset */
 277         if (op->atom == DW_OP_fbreg) {
 278                 if (fb_ops == NULL)
 279                         return -ENOTSUP;
 280                 ref = true;
 281                 offs = op->number;
 282                 op = &fb_ops[0];
 283         }
 284
 285         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 286                 regn = op->atom - DW_OP_breg0;
 287                 offs += op->number;
 288                 ref = true;
 289         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 290                 regn = op->atom - DW_OP_reg0;
 291         } else if (op->atom == DW_OP_bregx) {
 292                 regn = op->number;
 293                 offs += op->number2;
 294                 ref = true;
 295         } else if (op->atom == DW_OP_regx) {
 296                 regn = op->number;
 297         } else {
 298                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 299                 return -ENOTSUP;
 300         }
 301
 302         if (!tvar)
 303                 return 0;
 304
 305         regs = get_arch_regstr(regn);
 306         if (!regs) {
 307                 /* This should be a bug in DWARF or this tool */
 308                 pr_warning("Mapping for the register number %u "
 309                            "missing on this architecture.\n", regn);
 310                 return -ERANGE;
 311         }
 312
 313         tvar->value = strdup(regs);
 314         if (tvar->value == NULL)
 315                 return -ENOMEM;
 316
 317         if (ref) {
 318                 tvar->ref = alloc_trace_arg_ref((long)offs);
 319                 if (tvar->ref == NULL)
 320                         return -ENOMEM;
 321         }
 322         return 0;
 323 }
 324
 325 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 326
 327 static int convert_variable_type(Dwarf_Die *vr_die,
 328                                  struct probe_trace_arg *tvar,
 329                                  const char *cast)
 330 {
 331         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 332         Dwarf_Die type;
 333         char buf[16];
 334         int bsize, boffs, total;
 335         int ret;
 336
 337         /* TODO: check all types */
 338         if (cast && strcmp(cast, "string") != 0) {
 339                 /* Non string type is OK */
 340                 tvar->type = strdup(cast);
 341                 return (tvar->type == NULL) ? -ENOMEM : 0;
 342         }
 343
 344         bsize = dwarf_bitsize(vr_die);
 345         if (bsize > 0) {
 346                 /* This is a bitfield */
 347                 boffs = dwarf_bitoffset(vr_die);
 348                 total = dwarf_bytesize(vr_die);
 349                 if (boffs < 0 || total < 0)
 350                         return -ENOENT;
 351                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 352                                 BYTES_TO_BITS(total));
 353                 goto formatted;
 354         }
 355
 356         if (die_get_real_type(vr_die, &type) == NULL) {
 357                 pr_warning("Failed to get a type information of %s.\n",
 358                            dwarf_diename(vr_die));
 359                 return -ENOENT;
 360         }
 361
 362         pr_debug("%s type is %s.\n",
 363                  dwarf_diename(vr_die), dwarf_diename(&type));
 364
 365         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 366                 ret = dwarf_tag(&type);
 367                 if (ret != DW_TAG_pointer_type &&
 368                     ret != DW_TAG_array_type) {
 369                         pr_warning("Failed to cast into string: "
 370                                    "%s(%s) is not a pointer nor array.\n",
 371                                    dwarf_diename(vr_die), dwarf_diename(&type));
 372                         return -EINVAL;
 373                 }
 374                 if (die_get_real_type(&type, &type) == NULL) {
 375                         pr_warning("Failed to get a type"
 376                                    " information.\n");
 377                         return -ENOENT;
 378                 }
 379                 if (ret == DW_TAG_pointer_type) {
 380                         while (*ref_ptr)
 381                                 ref_ptr = &(*ref_ptr)->next;
 382                         /* Add new reference with offset +0 */
 383                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 384                         if (*ref_ptr == NULL) {
 385                                 pr_warning("Out of memory error\n");
 386                                 return -ENOMEM;
 387                         }
 388                 }
 389                 if (!die_compare_name(&type, "char") &&
 390                     !die_compare_name(&type, "unsigned char")) {
 391                         pr_warning("Failed to cast into string: "
 392                                    "%s is not (unsigned) char *.\n",
 393                                    dwarf_diename(vr_die));
 394                         return -EINVAL;
 395                 }
 396                 tvar->type = strdup(cast);
 397                 return (tvar->type == NULL) ? -ENOMEM : 0;
 398         }
 399
 400         ret = dwarf_bytesize(&type);
 401         if (ret <= 0)
 402                 /* No size ... try to use default type */
 403                 return 0;
 404         ret = BYTES_TO_BITS(ret);
 405
 406         /* Check the bitwidth */
 407         if (ret > MAX_BASIC_TYPE_BITS) {
 408                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 409                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 410                 ret = MAX_BASIC_TYPE_BITS;
 411         }
 412         ret = snprintf(buf, 16, "%c%d",
 413                        die_is_signed_type(&type) ? 's' : 'u', ret);
 414
 415 formatted:
 416         if (ret < 0 || ret >= 16) {
 417                 if (ret >= 16)
 418                         ret = -E2BIG;
 419                 pr_warning("Failed to convert variable type: %s\n",
 420                            strerror(-ret));
 421                 return ret;
 422         }
 423         tvar->type = strdup(buf);
 424         if (tvar->type == NULL)
 425                 return -ENOMEM;
 426         return 0;
 427 }
 428
 429 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 430                                     struct perf_probe_arg_field *field,
 431                                     struct probe_trace_arg_ref **ref_ptr,
 432                                     Dwarf_Die *die_mem)
 433 {
 434         struct probe_trace_arg_ref *ref = *ref_ptr;
 435         Dwarf_Die type;
 436         Dwarf_Word offs;
 437         int ret, tag;
 438
 439         pr_debug("converting %s in %s\n", field->name, varname);
 440         if (die_get_real_type(vr_die, &type) == NULL) {
 441                 pr_warning("Failed to get the type of %s.\n", varname);
 442                 return -ENOENT;
 443         }
 444         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 445         tag = dwarf_tag(&type);
 446
 447         if (field->name[0] == '[' &&
 448             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 449                 if (field->next)
 450                         /* Save original type for next field */
 451                         memcpy(die_mem, &type, sizeof(*die_mem));
 452                 /* Get the type of this array */
 453                 if (die_get_real_type(&type, &type) == NULL) {
 454                         pr_warning("Failed to get the type of %s.\n", varname);
 455                         return -ENOENT;
 456                 }
 457                 pr_debug2("Array real type: (%x)\n",
 458                          (unsigned)dwarf_dieoffset(&type));
 459                 if (tag == DW_TAG_pointer_type) {
 460                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 461                         if (ref == NULL)
 462                                 return -ENOMEM;
 463                         if (*ref_ptr)
 464                                 (*ref_ptr)->next = ref;
 465                         else
 466                                 *ref_ptr = ref;
 467                 }
 468                 ref->offset += dwarf_bytesize(&type) * field->index;
 469                 if (!field->next)
 470                         /* Save vr_die for converting types */
 471                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 472                 goto next;
 473         } else if (tag == DW_TAG_pointer_type) {
 474                 /* Check the pointer and dereference */
 475                 if (!field->ref) {
 476                         pr_err("Semantic error: %s must be referred by '->'\n",
 477                                field->name);
 478                         return -EINVAL;
 479                 }
 480                 /* Get the type pointed by this pointer */
 481                 if (die_get_real_type(&type, &type) == NULL) {
 482                         pr_warning("Failed to get the type of %s.\n", varname);
 483                         return -ENOENT;
 484                 }
 485                 /* Verify it is a data structure  */
 486                 tag = dwarf_tag(&type);
 487                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 488                         pr_warning("%s is not a data structure nor an union.\n",
 489                                    varname);
 490                         return -EINVAL;
 491                 }
 492
 493                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 494                 if (ref == NULL)
 495                         return -ENOMEM;
 496                 if (*ref_ptr)
 497                         (*ref_ptr)->next = ref;
 498                 else
 499                         *ref_ptr = ref;
 500         } else {
 501                 /* Verify it is a data structure  */
 502                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 503                         pr_warning("%s is not a data structure nor an union.\n",
 504                                    varname);
 505                         return -EINVAL;
 506                 }
 507                 if (field->name[0] == '[') {
 508                         pr_err("Semantic error: %s is not a pointor"
 509                                " nor array.\n", varname);
 510                         return -EINVAL;
 511                 }
 512                 if (field->ref) {
 513                         pr_err("Semantic error: %s must be referred by '.'\n",
 514                                field->name);
 515                         return -EINVAL;
 516                 }
 517                 if (!ref) {
 518                         pr_warning("Structure on a register is not "
 519                                    "supported yet.\n");
 520                         return -ENOTSUP;
 521                 }
 522         }
 523
 524         if (die_find_member(&type, field->name, die_mem) == NULL) {
 525                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 526                            dwarf_diename(&type), field->name);
 527                 return -EINVAL;
 528         }
 529
 530         /* Get the offset of the field */
 531         if (tag == DW_TAG_union_type) {
 532                 offs = 0;
 533         } else {
 534                 ret = die_get_data_member_location(die_mem, &offs);
 535                 if (ret < 0) {
 536                         pr_warning("Failed to get the offset of %s.\n",
 537                                    field->name);
 538                         return ret;
 539                 }
 540         }
 541         ref->offset += (long)offs;
 542
 543 next:
 544         /* Converting next field */
 545         if (field->next)
 546                 return convert_variable_fields(die_mem, field->name,
 547                                         field->next, &ref, die_mem);
 548         else
 549                 return 0;
 550 }
 551
 552 /* Show a variables in kprobe event format */
 553 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 554 {
 555         Dwarf_Die die_mem;
 556         int ret;
 557
 558         pr_debug("Converting variable %s into trace event.\n",
 559                  dwarf_diename(vr_die));
 560
 561         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 562                                         &pf->sp_die, pf->tvar);
 563         if (ret == -ENOENT)
 564                 pr_err("Failed to find the location of %s at this address.\n"
 565                        " Perhaps, it has been optimized out.\n", pf->pvar->var);
 566         else if (ret == -ENOTSUP)
 567                 pr_err("Sorry, we don't support this variable location yet.\n");
 568         else if (pf->pvar->field) {
 569                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 570                                               pf->pvar->field, &pf->tvar->ref,
 571                                               &die_mem);
 572                 vr_die = &die_mem;
 573         }
 574         if (ret == 0)
 575                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 576         /* *expr will be cached in libdw. Don't free it. */
 577         return ret;
 578 }
 579
 580 /* Find a variable in a scope DIE */
 581 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 582 {
 583         Dwarf_Die vr_die;
 584         char buf[32], *ptr;
 585         int ret = 0;
 586
 587         if (!is_c_varname(pf->pvar->var)) {
 588                 /* Copy raw parameters */
 589                 pf->tvar->value = strdup(pf->pvar->var);
 590                 if (pf->tvar->value == NULL)
 591                         return -ENOMEM;
 592                 if (pf->pvar->type) {
 593                         pf->tvar->type = strdup(pf->pvar->type);
 594                         if (pf->tvar->type == NULL)
 595                                 return -ENOMEM;
 596                 }
 597                 if (pf->pvar->name) {
 598                         pf->tvar->name = strdup(pf->pvar->name);
 599                         if (pf->tvar->name == NULL)
 600                                 return -ENOMEM;
 601                 } else
 602                         pf->tvar->name = NULL;
 603                 return 0;
 604         }
 605
 606         if (pf->pvar->name)
 607                 pf->tvar->name = strdup(pf->pvar->name);
 608         else {
 609                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 610                 if (ret < 0)
 611                         return ret;
 612                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 613                 if (ptr)
 614                         *ptr = '_';
 615                 pf->tvar->name = strdup(buf);
 616         }
 617         if (pf->tvar->name == NULL)
 618                 return -ENOMEM;
 619
 620         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 621         /* Search child die for local variables and parameters. */
 622         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 623                 /* Search again in global variables */
 624                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
 625                         ret = -ENOENT;
 626         }
 627         if (ret >= 0)
 628                 ret = convert_variable(&vr_die, pf);
 629
 630         if (ret < 0)
 631                 pr_warning("Failed to find '%s' in this function.\n",
 632                            pf->pvar->var);
 633         return ret;
 634 }
 635
 636 /* Convert subprogram DIE to trace point */
 637 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 638                                   Dwarf_Addr paddr, bool retprobe,
 639                                   struct probe_trace_point *tp)
 640 {
 641         Dwarf_Addr eaddr, highaddr;
 642         GElf_Sym sym;
 643         const char *symbol;
 644
 645         /* Verify the address is correct */
 646         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 647                 pr_warning("Failed to get entry address of %s\n",
 648                            dwarf_diename(sp_die));
 649                 return -ENOENT;
 650         }
 651         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 652                 pr_warning("Failed to get end address of %s\n",
 653                            dwarf_diename(sp_die));
 654                 return -ENOENT;
 655         }
 656         if (paddr > highaddr) {
 657                 pr_warning("Offset specified is greater than size of %s\n",
 658                            dwarf_diename(sp_die));
 659                 return -EINVAL;
 660         }
 661
 662         /* Get an appropriate symbol from symtab */
 663         symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 664         if (!symbol) {
 665                 pr_warning("Failed to find symbol at 0x%lx\n",
 666                            (unsigned long)paddr);
 667                 return -ENOENT;
 668         }
 669         tp->offset = (unsigned long)(paddr - sym.st_value);
 670         tp->address = (unsigned long)paddr;
 671         tp->symbol = strdup(symbol);
 672         if (!tp->symbol)
 673                 return -ENOMEM;
 674
 675         /* Return probe must be on the head of a subprogram */
 676         if (retprobe) {
 677                 if (eaddr != paddr) {
 678                         pr_warning("Return probe must be on the head of"
 679                                    " a real function.\n");
 680                         return -EINVAL;
 681                 }
 682                 tp->retprobe = true;
 683         }
 684
 685         return 0;
 686 }
 687
 688 /* Call probe_finder callback with scope DIE */
 689 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 690 {
 691         Dwarf_Attribute fb_attr;
 692         size_t nops;
 693         int ret;
 694
 695         if (!sc_die) {
 696                 pr_err("Caller must pass a scope DIE. Program error.\n");
 697                 return -EINVAL;
 698         }
 699
 700         /* If not a real subprogram, find a real one */
 701         if (!die_is_func_def(sc_die)) {
 702                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 703                         pr_warning("Failed to find probe point in any "
 704                                    "functions.\n");
 705                         return -ENOENT;
 706                 }
 707         } else
 708                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 709
 710         /* Get the frame base attribute/ops from subprogram */
 711         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 712         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 713         if (ret <= 0 || nops == 0) {
 714                 pf->fb_ops = NULL;
 715 #if _ELFUTILS_PREREQ(0, 142)
 716         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 717                    pf->cfi != NULL) {
 718                 Dwarf_Frame *frame;
 719                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 720                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 721                         pr_warning("Failed to get call frame on 0x%jx\n",
 722                                    (uintmax_t)pf->addr);
 723                         return -ENOENT;
 724                 }
 725 #endif
 726         }
 727
 728         /* Call finder's callback handler */
 729         ret = pf->callback(sc_die, pf);
 730
 731         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 732         pf->fb_ops = NULL;
 733
 734         return ret;
 735 }
 736
 737 struct find_scope_param {
 738         const char *function;
 739         const char *file;
 740         int line;
 741         int diff;
 742         Dwarf_Die *die_mem;
 743         bool found;
 744 };
 745
 746 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 747 {
 748         struct find_scope_param *fsp = data;
 749         const char *file;
 750         int lno;
 751
 752         /* Skip if declared file name does not match */
 753         if (fsp->file) {
 754                 file = dwarf_decl_file(fn_die);
 755                 if (!file || strcmp(fsp->file, file) != 0)
 756                         return 0;
 757         }
 758         /* If the function name is given, that's what user expects */
 759         if (fsp->function) {
 760                 if (die_compare_name(fn_die, fsp->function)) {
 761                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 762                         fsp->found = true;
 763                         return 1;
 764                 }
 765         } else {
 766                 /* With the line number, find the nearest declared DIE */
 767                 dwarf_decl_line(fn_die, &lno);
 768                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 769                         /* Keep a candidate and continue */
 770                         fsp->diff = fsp->line - lno;
 771                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 772                         fsp->found = true;
 773                 }
 774         }
 775         return 0;
 776 }
 777
 778 /* Find an appropriate scope fits to given conditions */
 779 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 780 {
 781         struct find_scope_param fsp = {
 782                 .function = pf->pev->point.function,
 783                 .file = pf->fname,
 784                 .line = pf->lno,
 785                 .diff = INT_MAX,
 786                 .die_mem = die_mem,
 787                 .found = false,
 788         };
 789
 790         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 791
 792         return fsp.found ? die_mem : NULL;
 793 }
 794
 795 static int probe_point_line_walker(const char *fname, int lineno,
 796                                    Dwarf_Addr addr, void *data)
 797 {
 798         struct probe_finder *pf = data;
 799         Dwarf_Die *sc_die, die_mem;
 800         int ret;
 801
 802         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 803                 return 0;
 804
 805         pf->addr = addr;
 806         sc_die = find_best_scope(pf, &die_mem);
 807         if (!sc_die) {
 808                 pr_warning("Failed to find scope of probe point.\n");
 809                 return -ENOENT;
 810         }
 811
 812         ret = call_probe_finder(sc_die, pf);
 813
 814         /* Continue if no error, because the line will be in inline function */
 815         return ret < 0 ? ret : 0;
 816 }
 817
 818 /* Find probe point from its line number */
 819 static int find_probe_point_by_line(struct probe_finder *pf)
 820 {
 821         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 822 }
 823
 824 /* Find lines which match lazy pattern */
 825 static int find_lazy_match_lines(struct intlist *list,
 826                                  const char *fname, const char *pat)
 827 {
 828         FILE *fp;
 829         char *line = NULL;
 830         size_t line_len;
 831         ssize_t len;
 832         int count = 0, linenum = 1;
 833
 834         fp = fopen(fname, "r");
 835         if (!fp) {
 836                 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
 837                 return -errno;
 838         }
 839
 840         while ((len = getline(&line, &line_len, fp)) > 0) {
 841
 842                 if (line[len - 1] == '\n')
 843                         line[len - 1] = '\0';
 844
 845                 if (strlazymatch(line, pat)) {
 846                         intlist__add(list, linenum);
 847                         count++;
 848                 }
 849                 linenum++;
 850         }
 851
 852         if (ferror(fp))
 853                 count = -errno;
 854         free(line);
 855         fclose(fp);
 856
 857         if (count == 0)
 858                 pr_debug("No matched lines found in %s.\n", fname);
 859         return count;
 860 }
 861
 862 static int probe_point_lazy_walker(const char *fname, int lineno,
 863                                    Dwarf_Addr addr, void *data)
 864 {
 865         struct probe_finder *pf = data;
 866         Dwarf_Die *sc_die, die_mem;
 867         int ret;
 868
 869         if (!intlist__has_entry(pf->lcache, lineno) ||
 870             strtailcmp(fname, pf->fname) != 0)
 871                 return 0;
 872
 873         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 874                  lineno, (unsigned long long)addr);
 875         pf->addr = addr;
 876         pf->lno = lineno;
 877         sc_die = find_best_scope(pf, &die_mem);
 878         if (!sc_die) {
 879                 pr_warning("Failed to find scope of probe point.\n");
 880                 return -ENOENT;
 881         }
 882
 883         ret = call_probe_finder(sc_die, pf);
 884
 885         /*
 886          * Continue if no error, because the lazy pattern will match
 887          * to other lines
 888          */
 889         return ret < 0 ? ret : 0;
 890 }
 891
 892 /* Find probe points from lazy pattern  */
 893 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 894 {
 895         int ret = 0;
 896
 897         if (intlist__empty(pf->lcache)) {
 898                 /* Matching lazy line pattern */
 899                 ret = find_lazy_match_lines(pf->lcache, pf->fname,
 900                                             pf->pev->point.lazy_line);
 901                 if (ret <= 0)
 902                         return ret;
 903         }
 904
 905         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 906 }
 907
 908 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 909 {
 910         struct probe_finder *pf = data;
 911         struct perf_probe_point *pp = &pf->pev->point;
 912         Dwarf_Addr addr;
 913         int ret;
 914
 915         if (pp->lazy_line)
 916                 ret = find_probe_point_lazy(in_die, pf);
 917         else {
 918                 /* Get probe address */
 919                 if (dwarf_entrypc(in_die, &addr) != 0) {
 920                         pr_warning("Failed to get entry address of %s.\n",
 921                                    dwarf_diename(in_die));
 922                         return -ENOENT;
 923                 }
 924                 pf->addr = addr;
 925                 pf->addr += pp->offset;
 926                 pr_debug("found inline addr: 0x%jx\n",
 927                          (uintmax_t)pf->addr);
 928
 929                 ret = call_probe_finder(in_die, pf);
 930         }
 931
 932         return ret;
 933 }
 934
 935 /* Callback parameter with return value for libdw */
 936 struct dwarf_callback_param {
 937         void *data;
 938         int retval;
 939 };
 940
 941 /* Search function from function name */
 942 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 943 {
 944         struct dwarf_callback_param *param = data;
 945         struct probe_finder *pf = param->data;
 946         struct perf_probe_point *pp = &pf->pev->point;
 947
 948         /* Check tag and diename */
 949         if (!die_is_func_def(sp_die) ||
 950             !die_compare_name(sp_die, pp->function))
 951                 return DWARF_CB_OK;
 952
 953         /* Check declared file */
 954         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 955                 return DWARF_CB_OK;
 956
 957         pf->fname = dwarf_decl_file(sp_die);
 958         if (pp->line) { /* Function relative line */
 959                 dwarf_decl_line(sp_die, &pf->lno);
 960                 pf->lno += pp->line;
 961                 param->retval = find_probe_point_by_line(pf);
 962         } else if (!dwarf_func_inline(sp_die)) {
 963                 /* Real function */
 964                 if (pp->lazy_line)
 965                         param->retval = find_probe_point_lazy(sp_die, pf);
 966                 else {
 967                         if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
 968                                 pr_warning("Failed to get entry address of "
 969                                            "%s.\n", dwarf_diename(sp_die));
 970                                 param->retval = -ENOENT;
 971                                 return DWARF_CB_ABORT;
 972                         }
 973                         pf->addr += pp->offset;
 974                         /* TODO: Check the address in this function */
 975                         param->retval = call_probe_finder(sp_die, pf);
 976                 }
 977         } else
 978                 /* Inlined function: search instances */
 979                 param->retval = die_walk_instances(sp_die,
 980                                         probe_point_inline_cb, (void *)pf);
 981
 982         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 983 }
 984
 985 static int find_probe_point_by_func(struct probe_finder *pf)
 986 {
 987         struct dwarf_callback_param _param = {.data = (void *)pf,
 988                                               .retval = 0};
 989         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 990         return _param.retval;
 991 }
 992
 993 struct pubname_callback_param {
 994         char *function;
 995         char *file;
 996         Dwarf_Die *cu_die;
 997         Dwarf_Die *sp_die;
 998         int found;
 999 };
1000
1001 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1002 {
1003         struct pubname_callback_param *param = data;
1004
1005         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1006                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1007                         return DWARF_CB_OK;
1008
1009                 if (die_compare_name(param->sp_die, param->function)) {
1010                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1011                                 return DWARF_CB_OK;
1012
1013                         if (param->file &&
1014                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1015                                 return DWARF_CB_OK;
1016
1017                         param->found = 1;
1018                         return DWARF_CB_ABORT;
1019                 }
1020         }
1021
1022         return DWARF_CB_OK;
1023 }
1024
1025 /* Find probe points from debuginfo */
1026 static int debuginfo__find_probes(struct debuginfo *dbg,
1027                                   struct probe_finder *pf)
1028 {
1029         struct perf_probe_point *pp = &pf->pev->point;
1030         Dwarf_Off off, noff;
1031         size_t cuhl;
1032         Dwarf_Die *diep;
1033         int ret = 0;
1034
1035 #if _ELFUTILS_PREREQ(0, 142)
1036         /* Get the call frame information from this dwarf */
1037         pf->cfi = dwarf_getcfi(dbg->dbg);
1038 #endif
1039
1040         off = 0;
1041         pf->lcache = intlist__new(NULL);
1042         if (!pf->lcache)
1043                 return -ENOMEM;
1044
1045         /* Fastpath: lookup by function name from .debug_pubnames section */
1046         if (pp->function) {
1047                 struct pubname_callback_param pubname_param = {
1048                         .function = pp->function,
1049                         .file     = pp->file,
1050                         .cu_die   = &pf->cu_die,
1051                         .sp_die   = &pf->sp_die,
1052                         .found    = 0,
1053                 };
1054                 struct dwarf_callback_param probe_param = {
1055                         .data = pf,
1056                 };
1057
1058                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1059                                   &pubname_param, 0);
1060                 if (pubname_param.found) {
1061                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1062                         if (ret)
1063                                 goto found;
1064                 }
1065         }
1066
1067         /* Loop on CUs (Compilation Unit) */
1068         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1069                 /* Get the DIE(Debugging Information Entry) of this CU */
1070                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1071                 if (!diep)
1072                         continue;
1073
1074                 /* Check if target file is included. */
1075                 if (pp->file)
1076                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1077                 else
1078                         pf->fname = NULL;
1079
1080                 if (!pp->file || pf->fname) {
1081                         if (pp->function)
1082                                 ret = find_probe_point_by_func(pf);
1083                         else if (pp->lazy_line)
1084                                 ret = find_probe_point_lazy(NULL, pf);
1085                         else {
1086                                 pf->lno = pp->line;
1087                                 ret = find_probe_point_by_line(pf);
1088                         }
1089                         if (ret < 0)
1090                                 break;
1091                 }
1092                 off = noff;
1093         }
1094
1095 found:
1096         intlist__delete(pf->lcache);
1097         pf->lcache = NULL;
1098
1099         return ret;
1100 }
1101
1102 struct local_vars_finder {
1103         struct probe_finder *pf;
1104         struct perf_probe_arg *args;
1105         int max_args;
1106         int nargs;
1107         int ret;
1108 };
1109
1110 /* Collect available variables in this scope */
1111 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1112 {
1113         struct local_vars_finder *vf = data;
1114         struct probe_finder *pf = vf->pf;
1115         int tag;
1116
1117         tag = dwarf_tag(die_mem);
1118         if (tag == DW_TAG_formal_parameter ||
1119             tag == DW_TAG_variable) {
1120                 if (convert_variable_location(die_mem, vf->pf->addr,
1121                                               vf->pf->fb_ops, &pf->sp_die,
1122                                               NULL) == 0) {
1123                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1124                         if (vf->args[vf->nargs].var == NULL) {
1125                                 vf->ret = -ENOMEM;
1126                                 return DIE_FIND_CB_END;
1127                         }
1128                         pr_debug(" %s", vf->args[vf->nargs].var);
1129                         vf->nargs++;
1130                 }
1131         }
1132
1133         if (dwarf_haspc(die_mem, vf->pf->addr))
1134                 return DIE_FIND_CB_CONTINUE;
1135         else
1136                 return DIE_FIND_CB_SIBLING;
1137 }
1138
1139 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1140                              struct perf_probe_arg *args)
1141 {
1142         Dwarf_Die die_mem;
1143         int i;
1144         int n = 0;
1145         struct local_vars_finder vf = {.pf = pf, .args = args,
1146                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1147
1148         for (i = 0; i < pf->pev->nargs; i++) {
1149                 /* var never be NULL */
1150                 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1151                         pr_debug("Expanding $vars into:");
1152                         vf.nargs = n;
1153                         /* Special local variables */
1154                         die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1155                                        &die_mem);
1156                         pr_debug(" (%d)\n", vf.nargs - n);
1157                         if (vf.ret < 0)
1158                                 return vf.ret;
1159                         n = vf.nargs;
1160                 } else {
1161                         /* Copy normal argument */
1162                         args[n] = pf->pev->args[i];
1163                         n++;
1164                 }
1165         }
1166         return n;
1167 }
1168
1169 /* Add a found probe point into trace event list */
1170 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1171 {
1172         struct trace_event_finder *tf =
1173                         container_of(pf, struct trace_event_finder, pf);
1174         struct probe_trace_event *tev;
1175         struct perf_probe_arg *args;
1176         int ret, i;
1177
1178         /* Check number of tevs */
1179         if (tf->ntevs == tf->max_tevs) {
1180                 pr_warning("Too many( > %d) probe point found.\n",
1181                            tf->max_tevs);
1182                 return -ERANGE;
1183         }
1184         tev = &tf->tevs[tf->ntevs++];
1185
1186         /* Trace point should be converted from subprogram DIE */
1187         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1188                                      pf->pev->point.retprobe, &tev->point);
1189         if (ret < 0)
1190                 return ret;
1191
1192         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1193                  tev->point.offset);
1194
1195         /* Expand special probe argument if exist */
1196         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1197         if (args == NULL)
1198                 return -ENOMEM;
1199
1200         ret = expand_probe_args(sc_die, pf, args);
1201         if (ret < 0)
1202                 goto end;
1203
1204         tev->nargs = ret;
1205         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1206         if (tev->args == NULL) {
1207                 ret = -ENOMEM;
1208                 goto end;
1209         }
1210
1211         /* Find each argument */
1212         for (i = 0; i < tev->nargs; i++) {
1213                 pf->pvar = &args[i];
1214                 pf->tvar = &tev->args[i];
1215                 /* Variable should be found from scope DIE */
1216                 ret = find_variable(sc_die, pf);
1217                 if (ret != 0)
1218                         break;
1219         }
1220
1221 end:
1222         free(args);
1223         return ret;
1224 }
1225
1226 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1227 int debuginfo__find_trace_events(struct debuginfo *dbg,
1228                                  struct perf_probe_event *pev,
1229                                  struct probe_trace_event **tevs, int max_tevs)
1230 {
1231         struct trace_event_finder tf = {
1232                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1233                         .mod = dbg->mod, .max_tevs = max_tevs};
1234         int ret;
1235
1236         /* Allocate result tevs array */
1237         *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1238         if (*tevs == NULL)
1239                 return -ENOMEM;
1240
1241         tf.tevs = *tevs;
1242         tf.ntevs = 0;
1243
1244         ret = debuginfo__find_probes(dbg, &tf.pf);
1245         if (ret < 0) {
1246                 zfree(tevs);
1247                 return ret;
1248         }
1249
1250         return (ret < 0) ? ret : tf.ntevs;
1251 }
1252
1253 #define MAX_VAR_LEN 64
1254
1255 /* Collect available variables in this scope */
1256 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1257 {
1258         struct available_var_finder *af = data;
1259         struct variable_list *vl;
1260         char buf[MAX_VAR_LEN];
1261         int tag, ret;
1262
1263         vl = &af->vls[af->nvls - 1];
1264
1265         tag = dwarf_tag(die_mem);
1266         if (tag == DW_TAG_formal_parameter ||
1267             tag == DW_TAG_variable) {
1268                 ret = convert_variable_location(die_mem, af->pf.addr,
1269                                                 af->pf.fb_ops, &af->pf.sp_die,
1270                                                 NULL);
1271                 if (ret == 0) {
1272                         ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1273                         pr_debug2("Add new var: %s\n", buf);
1274                         if (ret > 0)
1275                                 strlist__add(vl->vars, buf);
1276                 }
1277         }
1278
1279         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1280                 return DIE_FIND_CB_CONTINUE;
1281         else
1282                 return DIE_FIND_CB_SIBLING;
1283 }
1284
1285 /* Add a found vars into available variables list */
1286 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1287 {
1288         struct available_var_finder *af =
1289                         container_of(pf, struct available_var_finder, pf);
1290         struct variable_list *vl;
1291         Dwarf_Die die_mem;
1292         int ret;
1293
1294         /* Check number of tevs */
1295         if (af->nvls == af->max_vls) {
1296                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1297                 return -ERANGE;
1298         }
1299         vl = &af->vls[af->nvls++];
1300
1301         /* Trace point should be converted from subprogram DIE */
1302         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1303                                      pf->pev->point.retprobe, &vl->point);
1304         if (ret < 0)
1305                 return ret;
1306
1307         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1308                  vl->point.offset);
1309
1310         /* Find local variables */
1311         vl->vars = strlist__new(true, NULL);
1312         if (vl->vars == NULL)
1313                 return -ENOMEM;
1314         af->child = true;
1315         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1316
1317         /* Find external variables */
1318         if (!af->externs)
1319                 goto out;
1320         /* Don't need to search child DIE for externs. */
1321         af->child = false;
1322         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1323
1324 out:
1325         if (strlist__empty(vl->vars)) {
1326                 strlist__delete(vl->vars);
1327                 vl->vars = NULL;
1328         }
1329
1330         return ret;
1331 }
1332
1333 /* Find available variables at given probe point */
1334 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1335                                       struct perf_probe_event *pev,
1336                                       struct variable_list **vls,
1337                                       int max_vls, bool externs)
1338 {
1339         struct available_var_finder af = {
1340                         .pf = {.pev = pev, .callback = add_available_vars},
1341                         .mod = dbg->mod,
1342                         .max_vls = max_vls, .externs = externs};
1343         int ret;
1344
1345         /* Allocate result vls array */
1346         *vls = zalloc(sizeof(struct variable_list) * max_vls);
1347         if (*vls == NULL)
1348                 return -ENOMEM;
1349
1350         af.vls = *vls;
1351         af.nvls = 0;
1352
1353         ret = debuginfo__find_probes(dbg, &af.pf);
1354         if (ret < 0) {
1355                 /* Free vlist for error */
1356                 while (af.nvls--) {
1357                         zfree(&af.vls[af.nvls].point.symbol);
1358                         strlist__delete(af.vls[af.nvls].vars);
1359                 }
1360                 zfree(vls);
1361                 return ret;
1362         }
1363
1364         return (ret < 0) ? ret : af.nvls;
1365 }
1366
1367 /* Reverse search */
1368 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1369                                 struct perf_probe_point *ppt)
1370 {
1371         Dwarf_Die cudie, spdie, indie;
1372         Dwarf_Addr _addr = 0, baseaddr = 0;
1373         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1374         int baseline = 0, lineno = 0, ret = 0;
1375
1376         /* Adjust address with bias */
1377         addr += dbg->bias;
1378
1379         /* Find cu die */
1380         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr - dbg->bias, &cudie)) {
1381                 pr_warning("Failed to find debug information for address %lx\n",
1382                            addr);
1383                 ret = -EINVAL;
1384                 goto end;
1385         }
1386
1387         /* Find a corresponding line (filename and lineno) */
1388         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1389         /* Don't care whether it failed or not */
1390
1391         /* Find a corresponding function (name, baseline and baseaddr) */
1392         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1393                 /* Get function entry information */
1394                 func = basefunc = dwarf_diename(&spdie);
1395                 if (!func ||
1396                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1397                     dwarf_decl_line(&spdie, &baseline) != 0) {
1398                         lineno = 0;
1399                         goto post;
1400                 }
1401
1402                 fname = dwarf_decl_file(&spdie);
1403                 if (addr == (unsigned long)baseaddr) {
1404                         /* Function entry - Relative line number is 0 */
1405                         lineno = baseline;
1406                         goto post;
1407                 }
1408
1409                 /* Track down the inline functions step by step */
1410                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1411                                                 &indie)) {
1412                         /* There is an inline function */
1413                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1414                             _addr == addr) {
1415                                 /*
1416                                  * addr is at an inline function entry.
1417                                  * In this case, lineno should be the call-site
1418                                  * line number. (overwrite lineinfo)
1419                                  */
1420                                 lineno = die_get_call_lineno(&indie);
1421                                 fname = die_get_call_file(&indie);
1422                                 break;
1423                         } else {
1424                                 /*
1425                                  * addr is in an inline function body.
1426                                  * Since lineno points one of the lines
1427                                  * of the inline function, baseline should
1428                                  * be the entry line of the inline function.
1429                                  */
1430                                 tmp = dwarf_diename(&indie);
1431                                 if (!tmp ||
1432                                     dwarf_decl_line(&indie, &baseline) != 0)
1433                                         break;
1434                                 func = tmp;
1435                                 spdie = indie;
1436                         }
1437                 }
1438                 /* Verify the lineno and baseline are in a same file */
1439                 tmp = dwarf_decl_file(&spdie);
1440                 if (!tmp || strcmp(tmp, fname) != 0)
1441                         lineno = 0;
1442         }
1443
1444 post:
1445         /* Make a relative line number or an offset */
1446         if (lineno)
1447                 ppt->line = lineno - baseline;
1448         else if (basefunc) {
1449                 ppt->offset = addr - (unsigned long)baseaddr;
1450                 func = basefunc;
1451         }
1452
1453         /* Duplicate strings */
1454         if (func) {
1455                 ppt->function = strdup(func);
1456                 if (ppt->function == NULL) {
1457                         ret = -ENOMEM;
1458                         goto end;
1459                 }
1460         }
1461         if (fname) {
1462                 ppt->file = strdup(fname);
1463                 if (ppt->file == NULL) {
1464                         zfree(&ppt->function);
1465                         ret = -ENOMEM;
1466                         goto end;
1467                 }
1468         }
1469 end:
1470         if (ret == 0 && (fname || func))
1471                 ret = 1;        /* Found a point */
1472         return ret;
1473 }
1474
1475 /* Add a line and store the src path */
1476 static int line_range_add_line(const char *src, unsigned int lineno,
1477                                struct line_range *lr)
1478 {
1479         /* Copy source path */
1480         if (!lr->path) {
1481                 lr->path = strdup(src);
1482                 if (lr->path == NULL)
1483                         return -ENOMEM;
1484         }
1485         return intlist__add(lr->line_list, lineno);
1486 }
1487
1488 static int line_range_walk_cb(const char *fname, int lineno,
1489                               Dwarf_Addr addr __maybe_unused,
1490                               void *data)
1491 {
1492         struct line_finder *lf = data;
1493
1494         if ((strtailcmp(fname, lf->fname) != 0) ||
1495             (lf->lno_s > lineno || lf->lno_e < lineno))
1496                 return 0;
1497
1498         if (line_range_add_line(fname, lineno, lf->lr) < 0)
1499                 return -EINVAL;
1500
1501         return 0;
1502 }
1503
1504 /* Find line range from its line number */
1505 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1506 {
1507         int ret;
1508
1509         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1510
1511         /* Update status */
1512         if (ret >= 0)
1513                 if (!intlist__empty(lf->lr->line_list))
1514                         ret = lf->found = 1;
1515                 else
1516                         ret = 0;        /* Lines are not found */
1517         else {
1518                 zfree(&lf->lr->path);
1519         }
1520         return ret;
1521 }
1522
1523 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1524 {
1525         find_line_range_by_line(in_die, data);
1526
1527         /*
1528          * We have to check all instances of inlined function, because
1529          * some execution paths can be optimized out depends on the
1530          * function argument of instances
1531          */
1532         return 0;
1533 }
1534
1535 /* Search function definition from function name */
1536 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1537 {
1538         struct dwarf_callback_param *param = data;
1539         struct line_finder *lf = param->data;
1540         struct line_range *lr = lf->lr;
1541
1542         /* Check declared file */
1543         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1544                 return DWARF_CB_OK;
1545
1546         if (die_is_func_def(sp_die) &&
1547             die_compare_name(sp_die, lr->function)) {
1548                 lf->fname = dwarf_decl_file(sp_die);
1549                 dwarf_decl_line(sp_die, &lr->offset);
1550                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1551                 lf->lno_s = lr->offset + lr->start;
1552                 if (lf->lno_s < 0)      /* Overflow */
1553                         lf->lno_s = INT_MAX;
1554                 lf->lno_e = lr->offset + lr->end;
1555                 if (lf->lno_e < 0)      /* Overflow */
1556                         lf->lno_e = INT_MAX;
1557                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1558                 lr->start = lf->lno_s;
1559                 lr->end = lf->lno_e;
1560                 if (dwarf_func_inline(sp_die))
1561                         param->retval = die_walk_instances(sp_die,
1562                                                 line_range_inline_cb, lf);
1563                 else
1564                         param->retval = find_line_range_by_line(sp_die, lf);
1565                 return DWARF_CB_ABORT;
1566         }
1567         return DWARF_CB_OK;
1568 }
1569
1570 static int find_line_range_by_func(struct line_finder *lf)
1571 {
1572         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1573         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1574         return param.retval;
1575 }
1576
1577 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1578 {
1579         struct line_finder lf = {.lr = lr, .found = 0};
1580         int ret = 0;
1581         Dwarf_Off off = 0, noff;
1582         size_t cuhl;
1583         Dwarf_Die *diep;
1584         const char *comp_dir;
1585
1586         /* Fastpath: lookup by function name from .debug_pubnames section */
1587         if (lr->function) {
1588                 struct pubname_callback_param pubname_param = {
1589                         .function = lr->function, .file = lr->file,
1590                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1591                 struct dwarf_callback_param line_range_param = {
1592                         .data = (void *)&lf, .retval = 0};
1593
1594                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1595                                   &pubname_param, 0);
1596                 if (pubname_param.found) {
1597                         line_range_search_cb(&lf.sp_die, &line_range_param);
1598                         if (lf.found)
1599                                 goto found;
1600                 }
1601         }
1602
1603         /* Loop on CUs (Compilation Unit) */
1604         while (!lf.found && ret >= 0) {
1605                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1606                                  NULL, NULL, NULL) != 0)
1607                         break;
1608
1609                 /* Get the DIE(Debugging Information Entry) of this CU */
1610                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1611                 if (!diep)
1612                         continue;
1613
1614                 /* Check if target file is included. */
1615                 if (lr->file)
1616                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1617                 else
1618                         lf.fname = 0;
1619
1620                 if (!lr->file || lf.fname) {
1621                         if (lr->function)
1622                                 ret = find_line_range_by_func(&lf);
1623                         else {
1624                                 lf.lno_s = lr->start;
1625                                 lf.lno_e = lr->end;
1626                                 ret = find_line_range_by_line(NULL, &lf);
1627                         }
1628                 }
1629                 off = noff;
1630         }
1631
1632 found:
1633         /* Store comp_dir */
1634         if (lf.found) {
1635                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1636                 if (comp_dir) {
1637                         lr->comp_dir = strdup(comp_dir);
1638                         if (!lr->comp_dir)
1639                                 ret = -ENOMEM;
1640                 }
1641         }
1642
1643         pr_debug("path: %s\n", lr->path);
1644         return (ret < 0) ? ret : lf.found;
1645 }
1646