tools/perf/util/probe-finder.c

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This source file includes following definitions.
debuginfo__init_offline_dwarf
__debuginfo__new
debuginfo__new
debuginfo__delete
alloc_trace_arg_ref
convert_variable_location
convert_variable_type
convert_variable_fields
convert_variable
find_variable
convert_to_trace_point
call_probe_finder
find_best_scope_cb
find_inner_scope_cb
find_best_scope
probe_point_line_walker
find_probe_point_by_line
find_lazy_match_lines
probe_point_lazy_walker
find_probe_point_lazy
skip_prologue
probe_point_inline_cb
probe_point_search_cb
find_probe_point_by_func
pubname_search_cb
debuginfo__find_probe_location
debuginfo__find_probes
copy_variables_cb
expand_probe_args
trace_event_finder_overlap
add_probe_trace_event
debuginfo__find_trace_events
collect_variables_cb
available_var_finder_overlap
add_available_vars
debuginfo__find_available_vars_at
debuginfo__get_text_offset
debuginfo__find_probe_point
line_range_add_line
line_range_walk_cb
find_line_range_by_line
line_range_inline_cb
line_range_search_cb
find_line_range_by_func
debuginfo__find_line_range
get_real_path
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * probe-finder.c : C expression to kprobe event converter
   4  *
   5  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   6  */
   7 
   8 #include <inttypes.h>
   9 #include <sys/utsname.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <fcntl.h>
  13 #include <errno.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <stdarg.h>
  19 #include <dwarf-regs.h>
  20 
  21 #include <linux/bitops.h>
  22 #include <linux/zalloc.h>
  23 #include "event.h"
  24 #include "dso.h"
  25 #include "debug.h"
  26 #include "intlist.h"
  27 #include "strbuf.h"
  28 #include "strlist.h"
  29 #include "symbol.h"
  30 #include "probe-finder.h"
  31 #include "probe-file.h"
  32 #include "string2.h"
  33 
  34 /* Kprobe tracer basic type is up to u64 */
  35 #define MAX_BASIC_TYPE_BITS     64
  36 
  37 /* Dwarf FL wrappers */
  38 static char *debuginfo_path;    /* Currently dummy */
  39 
  40 static const Dwfl_Callbacks offline_callbacks = {
  41         .find_debuginfo = dwfl_standard_find_debuginfo,
  42         .debuginfo_path = &debuginfo_path,
  43 
  44         .section_address = dwfl_offline_section_address,
  45 
  46         /* We use this table for core files too.  */
  47         .find_elf = dwfl_build_id_find_elf,
  48 };
  49 
  50 /* Get a Dwarf from offline image */
  51 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  52                                          const char *path)
  53 {
  54         int fd;
  55 
  56         fd = open(path, O_RDONLY);
  57         if (fd < 0)
  58                 return fd;
  59 
  60         dbg->dwfl = dwfl_begin(&offline_callbacks);
  61         if (!dbg->dwfl)
  62                 goto error;
  63 
  64         dwfl_report_begin(dbg->dwfl);
  65         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  66         if (!dbg->mod)
  67                 goto error;
  68 
  69         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  70         if (!dbg->dbg)
  71                 goto error;
  72 
  73         dwfl_report_end(dbg->dwfl, NULL, NULL);
  74 
  75         return 0;
  76 error:
  77         if (dbg->dwfl)
  78                 dwfl_end(dbg->dwfl);
  79         else
  80                 close(fd);
  81         memset(dbg, 0, sizeof(*dbg));
  82 
  83         return -ENOENT;
  84 }
  85 
  86 static struct debuginfo *__debuginfo__new(const char *path)
  87 {
  88         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  89         if (!dbg)
  90                 return NULL;
  91 
  92         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  93                 zfree(&dbg);
  94         if (dbg)
  95                 pr_debug("Open Debuginfo file: %s\n", path);
  96         return dbg;
  97 }
  98 
  99 enum dso_binary_type distro_dwarf_types[] = {
 100         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 101         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 102         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 103         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 104         DSO_BINARY_TYPE__NOT_FOUND,
 105 };
 106 
 107 struct debuginfo *debuginfo__new(const char *path)
 108 {
 109         enum dso_binary_type *type;
 110         char buf[PATH_MAX], nil = '\0';
 111         struct dso *dso;
 112         struct debuginfo *dinfo = NULL;
 113 
 114         /* Try to open distro debuginfo files */
 115         dso = dso__new(path);
 116         if (!dso)
 117                 goto out;
 118 
 119         for (type = distro_dwarf_types;
 120              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 121              type++) {
 122                 if (dso__read_binary_type_filename(dso, *type, &nil,
 123                                                    buf, PATH_MAX) < 0)
 124                         continue;
 125                 dinfo = __debuginfo__new(buf);
 126         }
 127         dso__put(dso);
 128 
 129 out:
 130         /* if failed to open all distro debuginfo, open given binary */
 131         return dinfo ? : __debuginfo__new(path);
 132 }
 133 
 134 void debuginfo__delete(struct debuginfo *dbg)
 135 {
 136         if (dbg) {
 137                 if (dbg->dwfl)
 138                         dwfl_end(dbg->dwfl);
 139                 free(dbg);
 140         }
 141 }
 142 
 143 /*
 144  * Probe finder related functions
 145  */
 146 
 147 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 148 {
 149         struct probe_trace_arg_ref *ref;
 150         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 151         if (ref != NULL)
 152                 ref->offset = offs;
 153         return ref;
 154 }
 155 
 156 /*
 157  * Convert a location into trace_arg.
 158  * If tvar == NULL, this just checks variable can be converted.
 159  * If fentry == true and vr_die is a parameter, do huristic search
 160  * for the location fuzzed by function entry mcount.
 161  */
 162 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 163                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 164                                      unsigned int machine,
 165                                      struct probe_trace_arg *tvar)
 166 {
 167         Dwarf_Attribute attr;
 168         Dwarf_Addr tmp = 0;
 169         Dwarf_Op *op;
 170         size_t nops;
 171         unsigned int regn;
 172         Dwarf_Word offs = 0;
 173         bool ref = false;
 174         const char *regs;
 175         int ret, ret2 = 0;
 176 
 177         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 178                 goto static_var;
 179 
 180         /* TODO: handle more than 1 exprs */
 181         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 182                 return -EINVAL; /* Broken DIE ? */
 183         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 184                 ret = dwarf_entrypc(sp_die, &tmp);
 185                 if (ret)
 186                         return -ENOENT;
 187 
 188                 if (probe_conf.show_location_range &&
 189                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 190                         ret2 = -ERANGE;
 191                 } else if (addr != tmp ||
 192                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 193                         return -ENOENT;
 194                 }
 195 
 196                 ret = dwarf_highpc(sp_die, &tmp);
 197                 if (ret)
 198                         return -ENOENT;
 199                 /*
 200                  * This is fuzzed by fentry mcount. We try to find the
 201                  * parameter location at the earliest address.
 202                  */
 203                 for (addr += 1; addr <= tmp; addr++) {
 204                         if (dwarf_getlocation_addr(&attr, addr, &op,
 205                                                    &nops, 1) > 0)
 206                                 goto found;
 207                 }
 208                 return -ENOENT;
 209         }
 210 found:
 211         if (nops == 0)
 212                 /* TODO: Support const_value */
 213                 return -ENOENT;
 214 
 215         if (op->atom == DW_OP_addr) {
 216 static_var:
 217                 if (!tvar)
 218                         return ret2;
 219                 /* Static variables on memory (not stack), make @varname */
 220                 ret = strlen(dwarf_diename(vr_die));
 221                 tvar->value = zalloc(ret + 2);
 222                 if (tvar->value == NULL)
 223                         return -ENOMEM;
 224                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 225                 tvar->ref = alloc_trace_arg_ref((long)offs);
 226                 if (tvar->ref == NULL)
 227                         return -ENOMEM;
 228                 return ret2;
 229         }
 230 
 231         /* If this is based on frame buffer, set the offset */
 232         if (op->atom == DW_OP_fbreg) {
 233                 if (fb_ops == NULL)
 234                         return -ENOTSUP;
 235                 ref = true;
 236                 offs = op->number;
 237                 op = &fb_ops[0];
 238         }
 239 
 240         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 241                 regn = op->atom - DW_OP_breg0;
 242                 offs += op->number;
 243                 ref = true;
 244         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 245                 regn = op->atom - DW_OP_reg0;
 246         } else if (op->atom == DW_OP_bregx) {
 247                 regn = op->number;
 248                 offs += op->number2;
 249                 ref = true;
 250         } else if (op->atom == DW_OP_regx) {
 251                 regn = op->number;
 252         } else {
 253                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 254                 return -ENOTSUP;
 255         }
 256 
 257         if (!tvar)
 258                 return ret2;
 259 
 260         regs = get_dwarf_regstr(regn, machine);
 261         if (!regs) {
 262                 /* This should be a bug in DWARF or this tool */
 263                 pr_warning("Mapping for the register number %u "
 264                            "missing on this architecture.\n", regn);
 265                 return -ENOTSUP;
 266         }
 267 
 268         tvar->value = strdup(regs);
 269         if (tvar->value == NULL)
 270                 return -ENOMEM;
 271 
 272         if (ref) {
 273                 tvar->ref = alloc_trace_arg_ref((long)offs);
 274                 if (tvar->ref == NULL)
 275                         return -ENOMEM;
 276         }
 277         return ret2;
 278 }
 279 
 280 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 281 
 282 static int convert_variable_type(Dwarf_Die *vr_die,
 283                                  struct probe_trace_arg *tvar,
 284                                  const char *cast, bool user_access)
 285 {
 286         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 287         Dwarf_Die type;
 288         char buf[16];
 289         char sbuf[STRERR_BUFSIZE];
 290         int bsize, boffs, total;
 291         int ret;
 292         char prefix;
 293 
 294         /* TODO: check all types */
 295         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 296             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 297                 /* Non string type is OK */
 298                 /* and respect signedness/hexadecimal cast */
 299                 tvar->type = strdup(cast);
 300                 return (tvar->type == NULL) ? -ENOMEM : 0;
 301         }
 302 
 303         bsize = dwarf_bitsize(vr_die);
 304         if (bsize > 0) {
 305                 /* This is a bitfield */
 306                 boffs = dwarf_bitoffset(vr_die);
 307                 total = dwarf_bytesize(vr_die);
 308                 if (boffs < 0 || total < 0)
 309                         return -ENOENT;
 310                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 311                                 BYTES_TO_BITS(total));
 312                 goto formatted;
 313         }
 314 
 315         if (die_get_real_type(vr_die, &type) == NULL) {
 316                 pr_warning("Failed to get a type information of %s.\n",
 317                            dwarf_diename(vr_die));
 318                 return -ENOENT;
 319         }
 320 
 321         pr_debug("%s type is %s.\n",
 322                  dwarf_diename(vr_die), dwarf_diename(&type));
 323 
 324         if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
 325                 /* String type */
 326                 ret = dwarf_tag(&type);
 327                 if (ret != DW_TAG_pointer_type &&
 328                     ret != DW_TAG_array_type) {
 329                         pr_warning("Failed to cast into string: "
 330                                    "%s(%s) is not a pointer nor array.\n",
 331                                    dwarf_diename(vr_die), dwarf_diename(&type));
 332                         return -EINVAL;
 333                 }
 334                 if (die_get_real_type(&type, &type) == NULL) {
 335                         pr_warning("Failed to get a type"
 336                                    " information.\n");
 337                         return -ENOENT;
 338                 }
 339                 if (ret == DW_TAG_pointer_type) {
 340                         while (*ref_ptr)
 341                                 ref_ptr = &(*ref_ptr)->next;
 342                         /* Add new reference with offset +0 */
 343                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 344                         if (*ref_ptr == NULL) {
 345                                 pr_warning("Out of memory error\n");
 346                                 return -ENOMEM;
 347                         }
 348                         (*ref_ptr)->user_access = user_access;
 349                 }
 350                 if (!die_compare_name(&type, "char") &&
 351                     !die_compare_name(&type, "unsigned char")) {
 352                         pr_warning("Failed to cast into string: "
 353                                    "%s is not (unsigned) char *.\n",
 354                                    dwarf_diename(vr_die));
 355                         return -EINVAL;
 356                 }
 357                 tvar->type = strdup(cast);
 358                 return (tvar->type == NULL) ? -ENOMEM : 0;
 359         }
 360 
 361         if (cast && (strcmp(cast, "u") == 0))
 362                 prefix = 'u';
 363         else if (cast && (strcmp(cast, "s") == 0))
 364                 prefix = 's';
 365         else if (cast && (strcmp(cast, "x") == 0) &&
 366                  probe_type_is_available(PROBE_TYPE_X))
 367                 prefix = 'x';
 368         else
 369                 prefix = die_is_signed_type(&type) ? 's' :
 370                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 371 
 372         ret = dwarf_bytesize(&type);
 373         if (ret <= 0)
 374                 /* No size ... try to use default type */
 375                 return 0;
 376         ret = BYTES_TO_BITS(ret);
 377 
 378         /* Check the bitwidth */
 379         if (ret > MAX_BASIC_TYPE_BITS) {
 380                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 381                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 382                 ret = MAX_BASIC_TYPE_BITS;
 383         }
 384         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 385 
 386 formatted:
 387         if (ret < 0 || ret >= 16) {
 388                 if (ret >= 16)
 389                         ret = -E2BIG;
 390                 pr_warning("Failed to convert variable type: %s\n",
 391                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 392                 return ret;
 393         }
 394         tvar->type = strdup(buf);
 395         if (tvar->type == NULL)
 396                 return -ENOMEM;
 397         return 0;
 398 }
 399 
 400 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 401                                     struct perf_probe_arg_field *field,
 402                                     struct probe_trace_arg_ref **ref_ptr,
 403                                     Dwarf_Die *die_mem, bool user_access)
 404 {
 405         struct probe_trace_arg_ref *ref = *ref_ptr;
 406         Dwarf_Die type;
 407         Dwarf_Word offs;
 408         int ret, tag;
 409 
 410         pr_debug("converting %s in %s\n", field->name, varname);
 411         if (die_get_real_type(vr_die, &type) == NULL) {
 412                 pr_warning("Failed to get the type of %s.\n", varname);
 413                 return -ENOENT;
 414         }
 415         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 416                   (unsigned)dwarf_dieoffset(&type));
 417         tag = dwarf_tag(&type);
 418 
 419         if (field->name[0] == '[' &&
 420             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 421                 /* Save original type for next field or type */
 422                 memcpy(die_mem, &type, sizeof(*die_mem));
 423                 /* Get the type of this array */
 424                 if (die_get_real_type(&type, &type) == NULL) {
 425                         pr_warning("Failed to get the type of %s.\n", varname);
 426                         return -ENOENT;
 427                 }
 428                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 429                          (unsigned)dwarf_dieoffset(&type));
 430                 if (tag == DW_TAG_pointer_type) {
 431                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 432                         if (ref == NULL)
 433                                 return -ENOMEM;
 434                         if (*ref_ptr)
 435                                 (*ref_ptr)->next = ref;
 436                         else
 437                                 *ref_ptr = ref;
 438                 }
 439                 ref->offset += dwarf_bytesize(&type) * field->index;
 440                 ref->user_access = user_access;
 441                 goto next;
 442         } else if (tag == DW_TAG_pointer_type) {
 443                 /* Check the pointer and dereference */
 444                 if (!field->ref) {
 445                         pr_err("Semantic error: %s must be referred by '->'\n",
 446                                field->name);
 447                         return -EINVAL;
 448                 }
 449                 /* Get the type pointed by this pointer */
 450                 if (die_get_real_type(&type, &type) == NULL) {
 451                         pr_warning("Failed to get the type of %s.\n", varname);
 452                         return -ENOENT;
 453                 }
 454                 /* Verify it is a data structure  */
 455                 tag = dwarf_tag(&type);
 456                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 457                         pr_warning("%s is not a data structure nor a union.\n",
 458                                    varname);
 459                         return -EINVAL;
 460                 }
 461 
 462                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 463                 if (ref == NULL)
 464                         return -ENOMEM;
 465                 if (*ref_ptr)
 466                         (*ref_ptr)->next = ref;
 467                 else
 468                         *ref_ptr = ref;
 469         } else {
 470                 /* Verify it is a data structure  */
 471                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 472                         pr_warning("%s is not a data structure nor a union.\n",
 473                                    varname);
 474                         return -EINVAL;
 475                 }
 476                 if (field->name[0] == '[') {
 477                         pr_err("Semantic error: %s is not a pointer"
 478                                " nor array.\n", varname);
 479                         return -EINVAL;
 480                 }
 481                 /* While prcessing unnamed field, we don't care about this */
 482                 if (field->ref && dwarf_diename(vr_die)) {
 483                         pr_err("Semantic error: %s must be referred by '.'\n",
 484                                field->name);
 485                         return -EINVAL;
 486                 }
 487                 if (!ref) {
 488                         pr_warning("Structure on a register is not "
 489                                    "supported yet.\n");
 490                         return -ENOTSUP;
 491                 }
 492         }
 493 
 494         if (die_find_member(&type, field->name, die_mem) == NULL) {
 495                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 496                            dwarf_diename(&type), field->name);
 497                 return -EINVAL;
 498         }
 499 
 500         /* Get the offset of the field */
 501         if (tag == DW_TAG_union_type) {
 502                 offs = 0;
 503         } else {
 504                 ret = die_get_data_member_location(die_mem, &offs);
 505                 if (ret < 0) {
 506                         pr_warning("Failed to get the offset of %s.\n",
 507                                    field->name);
 508                         return ret;
 509                 }
 510         }
 511         ref->offset += (long)offs;
 512         ref->user_access = user_access;
 513 
 514         /* If this member is unnamed, we need to reuse this field */
 515         if (!dwarf_diename(die_mem))
 516                 return convert_variable_fields(die_mem, varname, field,
 517                                                 &ref, die_mem, user_access);
 518 
 519 next:
 520         /* Converting next field */
 521         if (field->next)
 522                 return convert_variable_fields(die_mem, field->name,
 523                                 field->next, &ref, die_mem, user_access);
 524         else
 525                 return 0;
 526 }
 527 
 528 /* Show a variables in kprobe event format */
 529 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 530 {
 531         Dwarf_Die die_mem;
 532         int ret;
 533 
 534         pr_debug("Converting variable %s into trace event.\n",
 535                  dwarf_diename(vr_die));
 536 
 537         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 538                                         &pf->sp_die, pf->machine, pf->tvar);
 539         if (ret == -ENOENT || ret == -EINVAL) {
 540                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 541                        " Perhaps it has been optimized out.\n"
 542                        " Use -V with the --range option to show '%s' location range.\n",
 543                        pf->pvar->var, pf->pvar->var);
 544         } else if (ret == -ENOTSUP)
 545                 pr_err("Sorry, we don't support this variable location yet.\n");
 546         else if (ret == 0 && pf->pvar->field) {
 547                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 548                                               pf->pvar->field, &pf->tvar->ref,
 549                                               &die_mem, pf->pvar->user_access);
 550                 vr_die = &die_mem;
 551         }
 552         if (ret == 0)
 553                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
 554                                             pf->pvar->user_access);
 555         /* *expr will be cached in libdw. Don't free it. */
 556         return ret;
 557 }
 558 
 559 /* Find a variable in a scope DIE */
 560 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 561 {
 562         Dwarf_Die vr_die;
 563         char *buf, *ptr;
 564         int ret = 0;
 565 
 566         /* Copy raw parameters */
 567         if (!is_c_varname(pf->pvar->var))
 568                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 569 
 570         if (pf->pvar->name)
 571                 pf->tvar->name = strdup(pf->pvar->name);
 572         else {
 573                 buf = synthesize_perf_probe_arg(pf->pvar);
 574                 if (!buf)
 575                         return -ENOMEM;
 576                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 577                 if (ptr)
 578                         *ptr = '_';
 579                 pf->tvar->name = buf;
 580         }
 581         if (pf->tvar->name == NULL)
 582                 return -ENOMEM;
 583 
 584         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 585         /* Search child die for local variables and parameters. */
 586         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 587                 /* Search again in global variables */
 588                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 589                                                 0, &vr_die)) {
 590                         pr_warning("Failed to find '%s' in this function.\n",
 591                                    pf->pvar->var);
 592                         ret = -ENOENT;
 593                 }
 594         }
 595         if (ret >= 0)
 596                 ret = convert_variable(&vr_die, pf);
 597 
 598         return ret;
 599 }
 600 
 601 /* Convert subprogram DIE to trace point */
 602 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 603                                   Dwarf_Addr paddr, bool retprobe,
 604                                   const char *function,
 605                                   struct probe_trace_point *tp)
 606 {
 607         Dwarf_Addr eaddr;
 608         GElf_Sym sym;
 609         const char *symbol;
 610 
 611         /* Verify the address is correct */
 612         if (!dwarf_haspc(sp_die, paddr)) {
 613                 pr_warning("Specified offset is out of %s\n",
 614                            dwarf_diename(sp_die));
 615                 return -EINVAL;
 616         }
 617 
 618         if (dwarf_entrypc(sp_die, &eaddr) == 0) {
 619                 /* If the DIE has entrypc, use it. */
 620                 symbol = dwarf_diename(sp_die);
 621         } else {
 622                 /* Try to get actual symbol name and address from symtab */
 623                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 624                 eaddr = sym.st_value;
 625         }
 626         if (!symbol) {
 627                 pr_warning("Failed to find symbol at 0x%lx\n",
 628                            (unsigned long)paddr);
 629                 return -ENOENT;
 630         }
 631 
 632         tp->offset = (unsigned long)(paddr - eaddr);
 633         tp->address = (unsigned long)paddr;
 634         tp->symbol = strdup(symbol);
 635         if (!tp->symbol)
 636                 return -ENOMEM;
 637 
 638         /* Return probe must be on the head of a subprogram */
 639         if (retprobe) {
 640                 if (eaddr != paddr) {
 641                         pr_warning("Failed to find \"%s%%return\",\n"
 642                                    " because %s is an inlined function and"
 643                                    " has no return point.\n", function,
 644                                    function);
 645                         return -EINVAL;
 646                 }
 647                 tp->retprobe = true;
 648         }
 649 
 650         return 0;
 651 }
 652 
 653 /* Call probe_finder callback with scope DIE */
 654 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 655 {
 656         Dwarf_Attribute fb_attr;
 657         Dwarf_Frame *frame = NULL;
 658         size_t nops;
 659         int ret;
 660 
 661         if (!sc_die) {
 662                 pr_err("Caller must pass a scope DIE. Program error.\n");
 663                 return -EINVAL;
 664         }
 665 
 666         /* If not a real subprogram, find a real one */
 667         if (!die_is_func_def(sc_die)) {
 668                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 669                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 670                                 pr_warning("Ignoring tail call from %s\n",
 671                                                 dwarf_diename(&pf->sp_die));
 672                                 return 0;
 673                         } else {
 674                                 pr_warning("Failed to find probe point in any "
 675                                            "functions.\n");
 676                                 return -ENOENT;
 677                         }
 678                 }
 679         } else
 680                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 681 
 682         /* Get the frame base attribute/ops from subprogram */
 683         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 684         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 685         if (ret <= 0 || nops == 0) {
 686                 pf->fb_ops = NULL;
 687 #if _ELFUTILS_PREREQ(0, 142)
 688         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 689                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 690                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 691                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 692                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 693                         pr_warning("Failed to get call frame on 0x%jx\n",
 694                                    (uintmax_t)pf->addr);
 695                         free(frame);
 696                         return -ENOENT;
 697                 }
 698 #endif
 699         }
 700 
 701         /* Call finder's callback handler */
 702         ret = pf->callback(sc_die, pf);
 703 
 704         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 705         free(frame);
 706         pf->fb_ops = NULL;
 707 
 708         return ret;
 709 }
 710 
 711 struct find_scope_param {
 712         const char *function;
 713         const char *file;
 714         int line;
 715         int diff;
 716         Dwarf_Die *die_mem;
 717         bool found;
 718 };
 719 
 720 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 721 {
 722         struct find_scope_param *fsp = data;
 723         const char *file;
 724         int lno;
 725 
 726         /* Skip if declared file name does not match */
 727         if (fsp->file) {
 728                 file = dwarf_decl_file(fn_die);
 729                 if (!file || strcmp(fsp->file, file) != 0)
 730                         return 0;
 731         }
 732         /* If the function name is given, that's what user expects */
 733         if (fsp->function) {
 734                 if (die_match_name(fn_die, fsp->function)) {
 735                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 736                         fsp->found = true;
 737                         return 1;
 738                 }
 739         } else {
 740                 /* With the line number, find the nearest declared DIE */
 741                 dwarf_decl_line(fn_die, &lno);
 742                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 743                         /* Keep a candidate and continue */
 744                         fsp->diff = fsp->line - lno;
 745                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 746                         fsp->found = true;
 747                 }
 748         }
 749         return 0;
 750 }
 751 
 752 /* Return innermost DIE */
 753 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
 754 {
 755         struct find_scope_param *fsp = data;
 756 
 757         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 758         fsp->found = true;
 759         return 1;
 760 }
 761 
 762 /* Find an appropriate scope fits to given conditions */
 763 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 764 {
 765         struct find_scope_param fsp = {
 766                 .function = pf->pev->point.function,
 767                 .file = pf->fname,
 768                 .line = pf->lno,
 769                 .diff = INT_MAX,
 770                 .die_mem = die_mem,
 771                 .found = false,
 772         };
 773         int ret;
 774 
 775         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
 776                                    &fsp);
 777         if (!ret && !fsp.found)
 778                 cu_walk_functions_at(&pf->cu_die, pf->addr,
 779                                      find_inner_scope_cb, &fsp);
 780 
 781         return fsp.found ? die_mem : NULL;
 782 }
 783 
 784 static int probe_point_line_walker(const char *fname, int lineno,
 785                                    Dwarf_Addr addr, void *data)
 786 {
 787         struct probe_finder *pf = data;
 788         Dwarf_Die *sc_die, die_mem;
 789         int ret;
 790 
 791         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 792                 return 0;
 793 
 794         pf->addr = addr;
 795         sc_die = find_best_scope(pf, &die_mem);
 796         if (!sc_die) {
 797                 pr_warning("Failed to find scope of probe point.\n");
 798                 return -ENOENT;
 799         }
 800 
 801         ret = call_probe_finder(sc_die, pf);
 802 
 803         /* Continue if no error, because the line will be in inline function */
 804         return ret < 0 ? ret : 0;
 805 }
 806 
 807 /* Find probe point from its line number */
 808 static int find_probe_point_by_line(struct probe_finder *pf)
 809 {
 810         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 811 }
 812 
 813 /* Find lines which match lazy pattern */
 814 static int find_lazy_match_lines(struct intlist *list,
 815                                  const char *fname, const char *pat)
 816 {
 817         FILE *fp;
 818         char *line = NULL;
 819         size_t line_len;
 820         ssize_t len;
 821         int count = 0, linenum = 1;
 822         char sbuf[STRERR_BUFSIZE];
 823 
 824         fp = fopen(fname, "r");
 825         if (!fp) {
 826                 pr_warning("Failed to open %s: %s\n", fname,
 827                            str_error_r(errno, sbuf, sizeof(sbuf)));
 828                 return -errno;
 829         }
 830 
 831         while ((len = getline(&line, &line_len, fp)) > 0) {
 832 
 833                 if (line[len - 1] == '\n')
 834                         line[len - 1] = '\0';
 835 
 836                 if (strlazymatch(line, pat)) {
 837                         intlist__add(list, linenum);
 838                         count++;
 839                 }
 840                 linenum++;
 841         }
 842 
 843         if (ferror(fp))
 844                 count = -errno;
 845         free(line);
 846         fclose(fp);
 847 
 848         if (count == 0)
 849                 pr_debug("No matched lines found in %s.\n", fname);
 850         return count;
 851 }
 852 
 853 static int probe_point_lazy_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 (!intlist__has_entry(pf->lcache, lineno) ||
 861             strtailcmp(fname, pf->fname) != 0)
 862                 return 0;
 863 
 864         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 865                  lineno, (unsigned long long)addr);
 866         pf->addr = addr;
 867         pf->lno = lineno;
 868         sc_die = find_best_scope(pf, &die_mem);
 869         if (!sc_die) {
 870                 pr_warning("Failed to find scope of probe point.\n");
 871                 return -ENOENT;
 872         }
 873 
 874         ret = call_probe_finder(sc_die, pf);
 875 
 876         /*
 877          * Continue if no error, because the lazy pattern will match
 878          * to other lines
 879          */
 880         return ret < 0 ? ret : 0;
 881 }
 882 
 883 /* Find probe points from lazy pattern  */
 884 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 885 {
 886         int ret = 0;
 887         char *fpath;
 888 
 889         if (intlist__empty(pf->lcache)) {
 890                 const char *comp_dir;
 891 
 892                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 893                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 894                 if (ret < 0) {
 895                         pr_warning("Failed to find source file path.\n");
 896                         return ret;
 897                 }
 898 
 899                 /* Matching lazy line pattern */
 900                 ret = find_lazy_match_lines(pf->lcache, fpath,
 901                                             pf->pev->point.lazy_line);
 902                 free(fpath);
 903                 if (ret <= 0)
 904                         return ret;
 905         }
 906 
 907         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 908 }
 909 
 910 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 911 {
 912         struct perf_probe_point *pp = &pf->pev->point;
 913 
 914         /* Not uprobe? */
 915         if (!pf->pev->uprobes)
 916                 return;
 917 
 918         /* Compiled with optimization? */
 919         if (die_is_optimized_target(&pf->cu_die))
 920                 return;
 921 
 922         /* Don't know entrypc? */
 923         if (!pf->addr)
 924                 return;
 925 
 926         /* Only FUNC and FUNC@SRC are eligible. */
 927         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 928             pp->offset || pp->abs_address)
 929                 return;
 930 
 931         /* Not interested in func parameter? */
 932         if (!perf_probe_with_var(pf->pev))
 933                 return;
 934 
 935         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 936                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 937                 pf->addr);
 938 
 939         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 940 }
 941 
 942 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 943 {
 944         struct probe_finder *pf = data;
 945         struct perf_probe_point *pp = &pf->pev->point;
 946         Dwarf_Addr addr;
 947         int ret;
 948 
 949         if (pp->lazy_line)
 950                 ret = find_probe_point_lazy(in_die, pf);
 951         else {
 952                 /* Get probe address */
 953                 if (die_entrypc(in_die, &addr) != 0) {
 954                         pr_warning("Failed to get entry address of %s.\n",
 955                                    dwarf_diename(in_die));
 956                         return -ENOENT;
 957                 }
 958                 if (addr == 0) {
 959                         pr_debug("%s has no valid entry address. skipped.\n",
 960                                  dwarf_diename(in_die));
 961                         return -ENOENT;
 962                 }
 963                 pf->addr = addr;
 964                 pf->addr += pp->offset;
 965                 pr_debug("found inline addr: 0x%jx\n",
 966                          (uintmax_t)pf->addr);
 967 
 968                 ret = call_probe_finder(in_die, pf);
 969         }
 970 
 971         return ret;
 972 }
 973 
 974 /* Callback parameter with return value for libdw */
 975 struct dwarf_callback_param {
 976         void *data;
 977         int retval;
 978 };
 979 
 980 /* Search function from function name */
 981 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 982 {
 983         struct dwarf_callback_param *param = data;
 984         struct probe_finder *pf = param->data;
 985         struct perf_probe_point *pp = &pf->pev->point;
 986 
 987         /* Check tag and diename */
 988         if (!die_is_func_def(sp_die) ||
 989             !die_match_name(sp_die, pp->function))
 990                 return DWARF_CB_OK;
 991 
 992         /* Check declared file */
 993         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 994                 return DWARF_CB_OK;
 995 
 996         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
 997                  (unsigned long)dwarf_dieoffset(sp_die));
 998         pf->fname = dwarf_decl_file(sp_die);
 999         if (pp->line) { /* Function relative line */
1000                 dwarf_decl_line(sp_die, &pf->lno);
1001                 pf->lno += pp->line;
1002                 param->retval = find_probe_point_by_line(pf);
1003         } else if (die_is_func_instance(sp_die)) {
1004                 /* Instances always have the entry address */
1005                 die_entrypc(sp_die, &pf->addr);
1006                 /* But in some case the entry address is 0 */
1007                 if (pf->addr == 0) {
1008                         pr_debug("%s has no entry PC. Skipped\n",
1009                                  dwarf_diename(sp_die));
1010                         param->retval = 0;
1011                 /* Real function */
1012                 } else if (pp->lazy_line)
1013                         param->retval = find_probe_point_lazy(sp_die, pf);
1014                 else {
1015                         skip_prologue(sp_die, pf);
1016                         pf->addr += pp->offset;
1017                         /* TODO: Check the address in this function */
1018                         param->retval = call_probe_finder(sp_die, pf);
1019                 }
1020         } else if (!probe_conf.no_inlines) {
1021                 /* Inlined function: search instances */
1022                 param->retval = die_walk_instances(sp_die,
1023                                         probe_point_inline_cb, (void *)pf);
1024                 /* This could be a non-existed inline definition */
1025                 if (param->retval == -ENOENT)
1026                         param->retval = 0;
1027         }
1028 
1029         /* We need to find other candidates */
1030         if (strisglob(pp->function) && param->retval >= 0) {
1031                 param->retval = 0;      /* We have to clear the result */
1032                 return DWARF_CB_OK;
1033         }
1034 
1035         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1036 }
1037 
1038 static int find_probe_point_by_func(struct probe_finder *pf)
1039 {
1040         struct dwarf_callback_param _param = {.data = (void *)pf,
1041                                               .retval = 0};
1042         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1043         return _param.retval;
1044 }
1045 
1046 struct pubname_callback_param {
1047         char *function;
1048         char *file;
1049         Dwarf_Die *cu_die;
1050         Dwarf_Die *sp_die;
1051         int found;
1052 };
1053 
1054 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1055 {
1056         struct pubname_callback_param *param = data;
1057 
1058         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1059                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1060                         return DWARF_CB_OK;
1061 
1062                 if (die_match_name(param->sp_die, param->function)) {
1063                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1064                                 return DWARF_CB_OK;
1065 
1066                         if (param->file &&
1067                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1068                                 return DWARF_CB_OK;
1069 
1070                         param->found = 1;
1071                         return DWARF_CB_ABORT;
1072                 }
1073         }
1074 
1075         return DWARF_CB_OK;
1076 }
1077 
1078 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1079                                   struct probe_finder *pf)
1080 {
1081         struct perf_probe_point *pp = &pf->pev->point;
1082         Dwarf_Off off, noff;
1083         size_t cuhl;
1084         Dwarf_Die *diep;
1085         int ret = 0;
1086 
1087         off = 0;
1088         pf->lcache = intlist__new(NULL);
1089         if (!pf->lcache)
1090                 return -ENOMEM;
1091 
1092         /* Fastpath: lookup by function name from .debug_pubnames section */
1093         if (pp->function && !strisglob(pp->function)) {
1094                 struct pubname_callback_param pubname_param = {
1095                         .function = pp->function,
1096                         .file     = pp->file,
1097                         .cu_die   = &pf->cu_die,
1098                         .sp_die   = &pf->sp_die,
1099                         .found    = 0,
1100                 };
1101                 struct dwarf_callback_param probe_param = {
1102                         .data = pf,
1103                 };
1104 
1105                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1106                                   &pubname_param, 0);
1107                 if (pubname_param.found) {
1108                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1109                         if (ret)
1110                                 goto found;
1111                 }
1112         }
1113 
1114         /* Loop on CUs (Compilation Unit) */
1115         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1116                 /* Get the DIE(Debugging Information Entry) of this CU */
1117                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1118                 if (!diep)
1119                         continue;
1120 
1121                 /* Check if target file is included. */
1122                 if (pp->file)
1123                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1124                 else
1125                         pf->fname = NULL;
1126 
1127                 if (!pp->file || pf->fname) {
1128                         if (pp->function)
1129                                 ret = find_probe_point_by_func(pf);
1130                         else if (pp->lazy_line)
1131                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1132                         else {
1133                                 pf->lno = pp->line;
1134                                 ret = find_probe_point_by_line(pf);
1135                         }
1136                         if (ret < 0)
1137                                 break;
1138                 }
1139                 off = noff;
1140         }
1141 
1142 found:
1143         intlist__delete(pf->lcache);
1144         pf->lcache = NULL;
1145 
1146         return ret;
1147 }
1148 
1149 /* Find probe points from debuginfo */
1150 static int debuginfo__find_probes(struct debuginfo *dbg,
1151                                   struct probe_finder *pf)
1152 {
1153         int ret = 0;
1154         Elf *elf;
1155         GElf_Ehdr ehdr;
1156 
1157         if (pf->cfi_eh || pf->cfi_dbg)
1158                 return debuginfo__find_probe_location(dbg, pf);
1159 
1160         /* Get the call frame information from this dwarf */
1161         elf = dwarf_getelf(dbg->dbg);
1162         if (elf == NULL)
1163                 return -EINVAL;
1164 
1165         if (gelf_getehdr(elf, &ehdr) == NULL)
1166                 return -EINVAL;
1167 
1168         pf->machine = ehdr.e_machine;
1169 
1170 #if _ELFUTILS_PREREQ(0, 142)
1171         do {
1172                 GElf_Shdr shdr;
1173 
1174                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1175                     shdr.sh_type == SHT_PROGBITS)
1176                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1177 
1178                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1179         } while (0);
1180 #endif
1181 
1182         ret = debuginfo__find_probe_location(dbg, pf);
1183         return ret;
1184 }
1185 
1186 struct local_vars_finder {
1187         struct probe_finder *pf;
1188         struct perf_probe_arg *args;
1189         bool vars;
1190         int max_args;
1191         int nargs;
1192         int ret;
1193 };
1194 
1195 /* Collect available variables in this scope */
1196 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1197 {
1198         struct local_vars_finder *vf = data;
1199         struct probe_finder *pf = vf->pf;
1200         int tag;
1201 
1202         tag = dwarf_tag(die_mem);
1203         if (tag == DW_TAG_formal_parameter ||
1204             (tag == DW_TAG_variable && vf->vars)) {
1205                 if (convert_variable_location(die_mem, vf->pf->addr,
1206                                               vf->pf->fb_ops, &pf->sp_die,
1207                                               pf->machine, NULL) == 0) {
1208                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1209                         if (vf->args[vf->nargs].var == NULL) {
1210                                 vf->ret = -ENOMEM;
1211                                 return DIE_FIND_CB_END;
1212                         }
1213                         pr_debug(" %s", vf->args[vf->nargs].var);
1214                         vf->nargs++;
1215                 }
1216         }
1217 
1218         if (dwarf_haspc(die_mem, vf->pf->addr))
1219                 return DIE_FIND_CB_CONTINUE;
1220         else
1221                 return DIE_FIND_CB_SIBLING;
1222 }
1223 
1224 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1225                              struct perf_probe_arg *args)
1226 {
1227         Dwarf_Die die_mem;
1228         int i;
1229         int n = 0;
1230         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1231                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1232 
1233         for (i = 0; i < pf->pev->nargs; i++) {
1234                 /* var never be NULL */
1235                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1236                         vf.vars = true;
1237                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1238                         /* Copy normal argument */
1239                         args[n] = pf->pev->args[i];
1240                         n++;
1241                         continue;
1242                 }
1243                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1244                 vf.nargs = n;
1245                 /* Special local variables */
1246                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1247                                &die_mem);
1248                 pr_debug(" (%d)\n", vf.nargs - n);
1249                 if (vf.ret < 0)
1250                         return vf.ret;
1251                 n = vf.nargs;
1252         }
1253         return n;
1254 }
1255 
1256 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1257 {
1258         int i;
1259 
1260         for (i = 0; i < tf->ntevs; i++) {
1261                 if (tf->pf.addr == tf->tevs[i].point.address)
1262                         return true;
1263         }
1264         return false;
1265 }
1266 
1267 /* Add a found probe point into trace event list */
1268 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1269 {
1270         struct trace_event_finder *tf =
1271                         container_of(pf, struct trace_event_finder, pf);
1272         struct perf_probe_point *pp = &pf->pev->point;
1273         struct probe_trace_event *tev;
1274         struct perf_probe_arg *args = NULL;
1275         int ret, i;
1276 
1277         /*
1278          * For some reason (e.g. different column assigned to same address)
1279          * This callback can be called with the address which already passed.
1280          * Ignore it first.
1281          */
1282         if (trace_event_finder_overlap(tf))
1283                 return 0;
1284 
1285         /* Check number of tevs */
1286         if (tf->ntevs == tf->max_tevs) {
1287                 pr_warning("Too many( > %d) probe point found.\n",
1288                            tf->max_tevs);
1289                 return -ERANGE;
1290         }
1291         tev = &tf->tevs[tf->ntevs++];
1292 
1293         /* Trace point should be converted from subprogram DIE */
1294         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1295                                      pp->retprobe, pp->function, &tev->point);
1296         if (ret < 0)
1297                 goto end;
1298 
1299         tev->point.realname = strdup(dwarf_diename(sc_die));
1300         if (!tev->point.realname) {
1301                 ret = -ENOMEM;
1302                 goto end;
1303         }
1304 
1305         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1306                  tev->point.offset);
1307 
1308         /* Expand special probe argument if exist */
1309         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1310         if (args == NULL) {
1311                 ret = -ENOMEM;
1312                 goto end;
1313         }
1314 
1315         ret = expand_probe_args(sc_die, pf, args);
1316         if (ret < 0)
1317                 goto end;
1318 
1319         tev->nargs = ret;
1320         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1321         if (tev->args == NULL) {
1322                 ret = -ENOMEM;
1323                 goto end;
1324         }
1325 
1326         /* Find each argument */
1327         for (i = 0; i < tev->nargs; i++) {
1328                 pf->pvar = &args[i];
1329                 pf->tvar = &tev->args[i];
1330                 /* Variable should be found from scope DIE */
1331                 ret = find_variable(sc_die, pf);
1332                 if (ret != 0)
1333                         break;
1334         }
1335 
1336 end:
1337         if (ret) {
1338                 clear_probe_trace_event(tev);
1339                 tf->ntevs--;
1340         }
1341         free(args);
1342         return ret;
1343 }
1344 
1345 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1346 int debuginfo__find_trace_events(struct debuginfo *dbg,
1347                                  struct perf_probe_event *pev,
1348                                  struct probe_trace_event **tevs)
1349 {
1350         struct trace_event_finder tf = {
1351                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1352                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1353         int ret, i;
1354 
1355         /* Allocate result tevs array */
1356         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1357         if (*tevs == NULL)
1358                 return -ENOMEM;
1359 
1360         tf.tevs = *tevs;
1361         tf.ntevs = 0;
1362 
1363         ret = debuginfo__find_probes(dbg, &tf.pf);
1364         if (ret < 0) {
1365                 for (i = 0; i < tf.ntevs; i++)
1366                         clear_probe_trace_event(&tf.tevs[i]);
1367                 zfree(tevs);
1368                 return ret;
1369         }
1370 
1371         return (ret < 0) ? ret : tf.ntevs;
1372 }
1373 
1374 /* Collect available variables in this scope */
1375 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1376 {
1377         struct available_var_finder *af = data;
1378         struct variable_list *vl;
1379         struct strbuf buf = STRBUF_INIT;
1380         int tag, ret;
1381 
1382         vl = &af->vls[af->nvls - 1];
1383 
1384         tag = dwarf_tag(die_mem);
1385         if (tag == DW_TAG_formal_parameter ||
1386             tag == DW_TAG_variable) {
1387                 ret = convert_variable_location(die_mem, af->pf.addr,
1388                                                 af->pf.fb_ops, &af->pf.sp_die,
1389                                                 af->pf.machine, NULL);
1390                 if (ret == 0 || ret == -ERANGE) {
1391                         int ret2;
1392                         bool externs = !af->child;
1393 
1394                         if (strbuf_init(&buf, 64) < 0)
1395                                 goto error;
1396 
1397                         if (probe_conf.show_location_range) {
1398                                 if (!externs)
1399                                         ret2 = strbuf_add(&buf,
1400                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1401                                 else
1402                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1403                                 if (ret2)
1404                                         goto error;
1405                         }
1406 
1407                         ret2 = die_get_varname(die_mem, &buf);
1408 
1409                         if (!ret2 && probe_conf.show_location_range &&
1410                                 !externs) {
1411                                 if (strbuf_addch(&buf, '\t') < 0)
1412                                         goto error;
1413                                 ret2 = die_get_var_range(&af->pf.sp_die,
1414                                                         die_mem, &buf);
1415                         }
1416 
1417                         pr_debug("Add new var: %s\n", buf.buf);
1418                         if (ret2 == 0) {
1419                                 strlist__add(vl->vars,
1420                                         strbuf_detach(&buf, NULL));
1421                         }
1422                         strbuf_release(&buf);
1423                 }
1424         }
1425 
1426         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1427                 return DIE_FIND_CB_CONTINUE;
1428         else
1429                 return DIE_FIND_CB_SIBLING;
1430 error:
1431         strbuf_release(&buf);
1432         pr_debug("Error in strbuf\n");
1433         return DIE_FIND_CB_END;
1434 }
1435 
1436 static bool available_var_finder_overlap(struct available_var_finder *af)
1437 {
1438         int i;
1439 
1440         for (i = 0; i < af->nvls; i++) {
1441                 if (af->pf.addr == af->vls[i].point.address)
1442                         return true;
1443         }
1444         return false;
1445 
1446 }
1447 
1448 /* Add a found vars into available variables list */
1449 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1450 {
1451         struct available_var_finder *af =
1452                         container_of(pf, struct available_var_finder, pf);
1453         struct perf_probe_point *pp = &pf->pev->point;
1454         struct variable_list *vl;
1455         Dwarf_Die die_mem;
1456         int ret;
1457 
1458         /*
1459          * For some reason (e.g. different column assigned to same address),
1460          * this callback can be called with the address which already passed.
1461          * Ignore it first.
1462          */
1463         if (available_var_finder_overlap(af))
1464                 return 0;
1465 
1466         /* Check number of tevs */
1467         if (af->nvls == af->max_vls) {
1468                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1469                 return -ERANGE;
1470         }
1471         vl = &af->vls[af->nvls++];
1472 
1473         /* Trace point should be converted from subprogram DIE */
1474         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1475                                      pp->retprobe, pp->function, &vl->point);
1476         if (ret < 0)
1477                 return ret;
1478 
1479         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1480                  vl->point.offset);
1481 
1482         /* Find local variables */
1483         vl->vars = strlist__new(NULL, NULL);
1484         if (vl->vars == NULL)
1485                 return -ENOMEM;
1486         af->child = true;
1487         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1488 
1489         /* Find external variables */
1490         if (!probe_conf.show_ext_vars)
1491                 goto out;
1492         /* Don't need to search child DIE for external vars. */
1493         af->child = false;
1494         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1495 
1496 out:
1497         if (strlist__empty(vl->vars)) {
1498                 strlist__delete(vl->vars);
1499                 vl->vars = NULL;
1500         }
1501 
1502         return ret;
1503 }
1504 
1505 /*
1506  * Find available variables at given probe point
1507  * Return the number of found probe points. Return 0 if there is no
1508  * matched probe point. Return <0 if an error occurs.
1509  */
1510 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1511                                       struct perf_probe_event *pev,
1512                                       struct variable_list **vls)
1513 {
1514         struct available_var_finder af = {
1515                         .pf = {.pev = pev, .callback = add_available_vars},
1516                         .mod = dbg->mod,
1517                         .max_vls = probe_conf.max_probes};
1518         int ret;
1519 
1520         /* Allocate result vls array */
1521         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1522         if (*vls == NULL)
1523                 return -ENOMEM;
1524 
1525         af.vls = *vls;
1526         af.nvls = 0;
1527 
1528         ret = debuginfo__find_probes(dbg, &af.pf);
1529         if (ret < 0) {
1530                 /* Free vlist for error */
1531                 while (af.nvls--) {
1532                         zfree(&af.vls[af.nvls].point.symbol);
1533                         strlist__delete(af.vls[af.nvls].vars);
1534                 }
1535                 zfree(vls);
1536                 return ret;
1537         }
1538 
1539         return (ret < 0) ? ret : af.nvls;
1540 }
1541 
1542 /* For the kernel module, we need a special code to get a DIE */
1543 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1544                                 bool adjust_offset)
1545 {
1546         int n, i;
1547         Elf32_Word shndx;
1548         Elf_Scn *scn;
1549         Elf *elf;
1550         GElf_Shdr mem, *shdr;
1551         const char *p;
1552 
1553         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1554         if (!elf)
1555                 return -EINVAL;
1556 
1557         /* Get the number of relocations */
1558         n = dwfl_module_relocations(dbg->mod);
1559         if (n < 0)
1560                 return -ENOENT;
1561         /* Search the relocation related .text section */
1562         for (i = 0; i < n; i++) {
1563                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1564                 if (strcmp(p, ".text") == 0) {
1565                         /* OK, get the section header */
1566                         scn = elf_getscn(elf, shndx);
1567                         if (!scn)
1568                                 return -ENOENT;
1569                         shdr = gelf_getshdr(scn, &mem);
1570                         if (!shdr)
1571                                 return -ENOENT;
1572                         *offs = shdr->sh_addr;
1573                         if (adjust_offset)
1574                                 *offs -= shdr->sh_offset;
1575                 }
1576         }
1577         return 0;
1578 }
1579 
1580 /* Reverse search */
1581 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1582                                 struct perf_probe_point *ppt)
1583 {
1584         Dwarf_Die cudie, spdie, indie;
1585         Dwarf_Addr _addr = 0, baseaddr = 0;
1586         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1587         int baseline = 0, lineno = 0, ret = 0;
1588 
1589         /* We always need to relocate the address for aranges */
1590         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1591                 addr += baseaddr;
1592         /* Find cu die */
1593         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1594                 pr_warning("Failed to find debug information for address %lx\n",
1595                            addr);
1596                 ret = -EINVAL;
1597                 goto end;
1598         }
1599 
1600         /* Find a corresponding line (filename and lineno) */
1601         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1602         /* Don't care whether it failed or not */
1603 
1604         /* Find a corresponding function (name, baseline and baseaddr) */
1605         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1606                 /* Get function entry information */
1607                 func = basefunc = dwarf_diename(&spdie);
1608                 if (!func ||
1609                     die_entrypc(&spdie, &baseaddr) != 0 ||
1610                     dwarf_decl_line(&spdie, &baseline) != 0) {
1611                         lineno = 0;
1612                         goto post;
1613                 }
1614 
1615                 fname = dwarf_decl_file(&spdie);
1616                 if (addr == (unsigned long)baseaddr) {
1617                         /* Function entry - Relative line number is 0 */
1618                         lineno = baseline;
1619                         goto post;
1620                 }
1621 
1622                 /* Track down the inline functions step by step */
1623                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1624                                                 &indie)) {
1625                         /* There is an inline function */
1626                         if (die_entrypc(&indie, &_addr) == 0 &&
1627                             _addr == addr) {
1628                                 /*
1629                                  * addr is at an inline function entry.
1630                                  * In this case, lineno should be the call-site
1631                                  * line number. (overwrite lineinfo)
1632                                  */
1633                                 lineno = die_get_call_lineno(&indie);
1634                                 fname = die_get_call_file(&indie);
1635                                 break;
1636                         } else {
1637                                 /*
1638                                  * addr is in an inline function body.
1639                                  * Since lineno points one of the lines
1640                                  * of the inline function, baseline should
1641                                  * be the entry line of the inline function.
1642                                  */
1643                                 tmp = dwarf_diename(&indie);
1644                                 if (!tmp ||
1645                                     dwarf_decl_line(&indie, &baseline) != 0)
1646                                         break;
1647                                 func = tmp;
1648                                 spdie = indie;
1649                         }
1650                 }
1651                 /* Verify the lineno and baseline are in a same file */
1652                 tmp = dwarf_decl_file(&spdie);
1653                 if (!tmp || strcmp(tmp, fname) != 0)
1654                         lineno = 0;
1655         }
1656 
1657 post:
1658         /* Make a relative line number or an offset */
1659         if (lineno)
1660                 ppt->line = lineno - baseline;
1661         else if (basefunc) {
1662                 ppt->offset = addr - (unsigned long)baseaddr;
1663                 func = basefunc;
1664         }
1665 
1666         /* Duplicate strings */
1667         if (func) {
1668                 ppt->function = strdup(func);
1669                 if (ppt->function == NULL) {
1670                         ret = -ENOMEM;
1671                         goto end;
1672                 }
1673         }
1674         if (fname) {
1675                 ppt->file = strdup(fname);
1676                 if (ppt->file == NULL) {
1677                         zfree(&ppt->function);
1678                         ret = -ENOMEM;
1679                         goto end;
1680                 }
1681         }
1682 end:
1683         if (ret == 0 && (fname || func))
1684                 ret = 1;        /* Found a point */
1685         return ret;
1686 }
1687 
1688 /* Add a line and store the src path */
1689 static int line_range_add_line(const char *src, unsigned int lineno,
1690                                struct line_range *lr)
1691 {
1692         /* Copy source path */
1693         if (!lr->path) {
1694                 lr->path = strdup(src);
1695                 if (lr->path == NULL)
1696                         return -ENOMEM;
1697         }
1698         return intlist__add(lr->line_list, lineno);
1699 }
1700 
1701 static int line_range_walk_cb(const char *fname, int lineno,
1702                               Dwarf_Addr addr __maybe_unused,
1703                               void *data)
1704 {
1705         struct line_finder *lf = data;
1706         int err;
1707 
1708         if ((strtailcmp(fname, lf->fname) != 0) ||
1709             (lf->lno_s > lineno || lf->lno_e < lineno))
1710                 return 0;
1711 
1712         err = line_range_add_line(fname, lineno, lf->lr);
1713         if (err < 0 && err != -EEXIST)
1714                 return err;
1715 
1716         return 0;
1717 }
1718 
1719 /* Find line range from its line number */
1720 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1721 {
1722         int ret;
1723 
1724         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1725 
1726         /* Update status */
1727         if (ret >= 0)
1728                 if (!intlist__empty(lf->lr->line_list))
1729                         ret = lf->found = 1;
1730                 else
1731                         ret = 0;        /* Lines are not found */
1732         else {
1733                 zfree(&lf->lr->path);
1734         }
1735         return ret;
1736 }
1737 
1738 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1739 {
1740         int ret = find_line_range_by_line(in_die, data);
1741 
1742         /*
1743          * We have to check all instances of inlined function, because
1744          * some execution paths can be optimized out depends on the
1745          * function argument of instances. However, if an error occurs,
1746          * it should be handled by the caller.
1747          */
1748         return ret < 0 ? ret : 0;
1749 }
1750 
1751 /* Search function definition from function name */
1752 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1753 {
1754         struct dwarf_callback_param *param = data;
1755         struct line_finder *lf = param->data;
1756         struct line_range *lr = lf->lr;
1757 
1758         /* Check declared file */
1759         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1760                 return DWARF_CB_OK;
1761 
1762         if (die_is_func_def(sp_die) &&
1763             die_match_name(sp_die, lr->function)) {
1764                 lf->fname = dwarf_decl_file(sp_die);
1765                 dwarf_decl_line(sp_die, &lr->offset);
1766                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1767                 lf->lno_s = lr->offset + lr->start;
1768                 if (lf->lno_s < 0)      /* Overflow */
1769                         lf->lno_s = INT_MAX;
1770                 lf->lno_e = lr->offset + lr->end;
1771                 if (lf->lno_e < 0)      /* Overflow */
1772                         lf->lno_e = INT_MAX;
1773                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1774                 lr->start = lf->lno_s;
1775                 lr->end = lf->lno_e;
1776                 if (!die_is_func_instance(sp_die))
1777                         param->retval = die_walk_instances(sp_die,
1778                                                 line_range_inline_cb, lf);
1779                 else
1780                         param->retval = find_line_range_by_line(sp_die, lf);
1781                 return DWARF_CB_ABORT;
1782         }
1783         return DWARF_CB_OK;
1784 }
1785 
1786 static int find_line_range_by_func(struct line_finder *lf)
1787 {
1788         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1789         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1790         return param.retval;
1791 }
1792 
1793 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1794 {
1795         struct line_finder lf = {.lr = lr, .found = 0};
1796         int ret = 0;
1797         Dwarf_Off off = 0, noff;
1798         size_t cuhl;
1799         Dwarf_Die *diep;
1800         const char *comp_dir;
1801 
1802         /* Fastpath: lookup by function name from .debug_pubnames section */
1803         if (lr->function) {
1804                 struct pubname_callback_param pubname_param = {
1805                         .function = lr->function, .file = lr->file,
1806                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1807                 struct dwarf_callback_param line_range_param = {
1808                         .data = (void *)&lf, .retval = 0};
1809 
1810                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1811                                   &pubname_param, 0);
1812                 if (pubname_param.found) {
1813                         line_range_search_cb(&lf.sp_die, &line_range_param);
1814                         if (lf.found)
1815                                 goto found;
1816                 }
1817         }
1818 
1819         /* Loop on CUs (Compilation Unit) */
1820         while (!lf.found && ret >= 0) {
1821                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1822                                  NULL, NULL, NULL) != 0)
1823                         break;
1824 
1825                 /* Get the DIE(Debugging Information Entry) of this CU */
1826                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1827                 if (!diep)
1828                         continue;
1829 
1830                 /* Check if target file is included. */
1831                 if (lr->file)
1832                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1833                 else
1834                         lf.fname = 0;
1835 
1836                 if (!lr->file || lf.fname) {
1837                         if (lr->function)
1838                                 ret = find_line_range_by_func(&lf);
1839                         else {
1840                                 lf.lno_s = lr->start;
1841                                 lf.lno_e = lr->end;
1842                                 ret = find_line_range_by_line(NULL, &lf);
1843                         }
1844                 }
1845                 off = noff;
1846         }
1847 
1848 found:
1849         /* Store comp_dir */
1850         if (lf.found) {
1851                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1852                 if (comp_dir) {
1853                         lr->comp_dir = strdup(comp_dir);
1854                         if (!lr->comp_dir)
1855                                 ret = -ENOMEM;
1856                 }
1857         }
1858 
1859         pr_debug("path: %s\n", lr->path);
1860         return (ret < 0) ? ret : lf.found;
1861 }
1862 
1863 /*
1864  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1865  * and chop off leading directories that do not exist. Result is passed back as
1866  * a newly allocated path on success.
1867  * Return 0 if file was found and readable, -errno otherwise.
1868  */
1869 int get_real_path(const char *raw_path, const char *comp_dir,
1870                          char **new_path)
1871 {
1872         const char *prefix = symbol_conf.source_prefix;
1873 
1874         if (!prefix) {
1875                 if (raw_path[0] != '/' && comp_dir)
1876                         /* If not an absolute path, try to use comp_dir */
1877                         prefix = comp_dir;
1878                 else {
1879                         if (access(raw_path, R_OK) == 0) {
1880                                 *new_path = strdup(raw_path);
1881                                 return *new_path ? 0 : -ENOMEM;
1882                         } else
1883                                 return -errno;
1884                 }
1885         }
1886 
1887         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1888         if (!*new_path)
1889                 return -ENOMEM;
1890 
1891         for (;;) {
1892                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1893 
1894                 if (access(*new_path, R_OK) == 0)
1895                         return 0;
1896 
1897                 if (!symbol_conf.source_prefix) {
1898                         /* In case of searching comp_dir, don't retry */
1899                         zfree(new_path);
1900                         return -errno;
1901                 }
1902 
1903                 switch (errno) {
1904                 case ENAMETOOLONG:
1905                 case ENOENT:
1906                 case EROFS:
1907                 case EFAULT:
1908                         raw_path = strchr(++raw_path, '/');
1909                         if (!raw_path) {
1910                                 zfree(new_path);
1911                                 return -ENOENT;
1912                         }
1913                         continue;
1914 
1915                 default:
1916                         zfree(new_path);
1917                         return -errno;
1918                 }
1919         }
1920 }
/* [<][>][^][v][top][bottom][index][help] */
root/tools/perf/util/probe-finder.c

DEFINITIONS
