tools/perf/util/probe-finder.c

   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 "event.h"
  23 #include "dso.h"
  24 #include "debug.h"
  25 #include "intlist.h"
  26 #include "util.h"
  27 #include "strlist.h"
  28 #include "symbol.h"
  29 #include "probe-finder.h"
  30 #include "probe-file.h"
  31 #include "string2.h"
  32
  33 /* Kprobe tracer basic type is up to u64 */
  34 #define MAX_BASIC_TYPE_BITS     64
  35
  36 /* Dwarf FL wrappers */
  37 static char *debuginfo_path;    /* Currently dummy */
  38
  39 static const Dwfl_Callbacks offline_callbacks = {
  40         .find_debuginfo = dwfl_standard_find_debuginfo,
  41         .debuginfo_path = &debuginfo_path,
  42
  43         .section_address = dwfl_offline_section_address,
  44
  45         /* We use this table for core files too.  */
  46         .find_elf = dwfl_build_id_find_elf,
  47 };
  48
  49 /* Get a Dwarf from offline image */
  50 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  51                                          const char *path)
  52 {
  53         int fd;
  54
  55         fd = open(path, O_RDONLY);
  56         if (fd < 0)
  57                 return fd;
  58
  59         dbg->dwfl = dwfl_begin(&offline_callbacks);
  60         if (!dbg->dwfl)
  61                 goto error;
  62
  63         dwfl_report_begin(dbg->dwfl);
  64         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  65         if (!dbg->mod)
  66                 goto error;
  67
  68         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  69         if (!dbg->dbg)
  70                 goto error;
  71
  72         dwfl_report_end(dbg->dwfl, NULL, NULL);
  73
  74         return 0;
  75 error:
  76         if (dbg->dwfl)
  77                 dwfl_end(dbg->dwfl);
  78         else
  79                 close(fd);
  80         memset(dbg, 0, sizeof(*dbg));
  81
  82         return -ENOENT;
  83 }
  84
  85 static struct debuginfo *__debuginfo__new(const char *path)
  86 {
  87         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  88         if (!dbg)
  89                 return NULL;
  90
  91         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  92                 zfree(&dbg);
  93         if (dbg)
  94                 pr_debug("Open Debuginfo file: %s\n", path);
  95         return dbg;
  96 }
  97
  98 enum dso_binary_type distro_dwarf_types[] = {
  99         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 100         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 101         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 102         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 103         DSO_BINARY_TYPE__NOT_FOUND,
 104 };
 105
 106 struct debuginfo *debuginfo__new(const char *path)
 107 {
 108         enum dso_binary_type *type;
 109         char buf[PATH_MAX], nil = '\0';
 110         struct dso *dso;
 111         struct debuginfo *dinfo = NULL;
 112
 113         /* Try to open distro debuginfo files */
 114         dso = dso__new(path);
 115         if (!dso)
 116                 goto out;
 117
 118         for (type = distro_dwarf_types;
 119              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 120              type++) {
 121                 if (dso__read_binary_type_filename(dso, *type, &nil,
 122                                                    buf, PATH_MAX) < 0)
 123                         continue;
 124                 dinfo = __debuginfo__new(buf);
 125         }
 126         dso__put(dso);
 127
 128 out:
 129         /* if failed to open all distro debuginfo, open given binary */
 130         return dinfo ? : __debuginfo__new(path);
 131 }
 132
 133 void debuginfo__delete(struct debuginfo *dbg)
 134 {
 135         if (dbg) {
 136                 if (dbg->dwfl)
 137                         dwfl_end(dbg->dwfl);
 138                 free(dbg);
 139         }
 140 }
 141
 142 /*
 143  * Probe finder related functions
 144  */
 145
 146 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 147 {
 148         struct probe_trace_arg_ref *ref;
 149         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 150         if (ref != NULL)
 151                 ref->offset = offs;
 152         return ref;
 153 }
 154
 155 /*
 156  * Convert a location into trace_arg.
 157  * If tvar == NULL, this just checks variable can be converted.
 158  * If fentry == true and vr_die is a parameter, do huristic search
 159  * for the location fuzzed by function entry mcount.
 160  */
 161 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 162                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 163                                      unsigned int machine,
 164                                      struct probe_trace_arg *tvar)
 165 {
 166         Dwarf_Attribute attr;
 167         Dwarf_Addr tmp = 0;
 168         Dwarf_Op *op;
 169         size_t nops;
 170         unsigned int regn;
 171         Dwarf_Word offs = 0;
 172         bool ref = false;
 173         const char *regs;
 174         int ret, ret2 = 0;
 175
 176         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 177                 goto static_var;
 178
 179         /* TODO: handle more than 1 exprs */
 180         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 181                 return -EINVAL; /* Broken DIE ? */
 182         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 183                 ret = dwarf_entrypc(sp_die, &tmp);
 184                 if (ret)
 185                         return -ENOENT;
 186
 187                 if (probe_conf.show_location_range &&
 188                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 189                         ret2 = -ERANGE;
 190                 } else if (addr != tmp ||
 191                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 192                         return -ENOENT;
 193                 }
 194
 195                 ret = dwarf_highpc(sp_die, &tmp);
 196                 if (ret)
 197                         return -ENOENT;
 198                 /*
 199                  * This is fuzzed by fentry mcount. We try to find the
 200                  * parameter location at the earliest address.
 201                  */
 202                 for (addr += 1; addr <= tmp; addr++) {
 203                         if (dwarf_getlocation_addr(&attr, addr, &op,
 204                                                    &nops, 1) > 0)
 205                                 goto found;
 206                 }
 207                 return -ENOENT;
 208         }
 209 found:
 210         if (nops == 0)
 211                 /* TODO: Support const_value */
 212                 return -ENOENT;
 213
 214         if (op->atom == DW_OP_addr) {
 215 static_var:
 216                 if (!tvar)
 217                         return ret2;
 218                 /* Static variables on memory (not stack), make @varname */
 219                 ret = strlen(dwarf_diename(vr_die));
 220                 tvar->value = zalloc(ret + 2);
 221                 if (tvar->value == NULL)
 222                         return -ENOMEM;
 223                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 224                 tvar->ref = alloc_trace_arg_ref((long)offs);
 225                 if (tvar->ref == NULL)
 226                         return -ENOMEM;
 227                 return ret2;
 228         }
 229
 230         /* If this is based on frame buffer, set the offset */
 231         if (op->atom == DW_OP_fbreg) {
 232                 if (fb_ops == NULL)
 233                         return -ENOTSUP;
 234                 ref = true;
 235                 offs = op->number;
 236                 op = &fb_ops[0];
 237         }
 238
 239         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 240                 regn = op->atom - DW_OP_breg0;
 241                 offs += op->number;
 242                 ref = true;
 243         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 244                 regn = op->atom - DW_OP_reg0;
 245         } else if (op->atom == DW_OP_bregx) {
 246                 regn = op->number;
 247                 offs += op->number2;
 248                 ref = true;
 249         } else if (op->atom == DW_OP_regx) {
 250                 regn = op->number;
 251         } else {
 252                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 253                 return -ENOTSUP;
 254         }
 255
 256         if (!tvar)
 257                 return ret2;
 258
 259         regs = get_dwarf_regstr(regn, machine);
 260         if (!regs) {
 261                 /* This should be a bug in DWARF or this tool */
 262                 pr_warning("Mapping for the register number %u "
 263                            "missing on this architecture.\n", regn);
 264                 return -ENOTSUP;
 265         }
 266
 267         tvar->value = strdup(regs);
 268         if (tvar->value == NULL)
 269                 return -ENOMEM;
 270
 271         if (ref) {
 272                 tvar->ref = alloc_trace_arg_ref((long)offs);
 273                 if (tvar->ref == NULL)
 274                         return -ENOMEM;
 275         }
 276         return ret2;
 277 }
 278
 279 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 280
 281 static int convert_variable_type(Dwarf_Die *vr_die,
 282                                  struct probe_trace_arg *tvar,
 283                                  const char *cast)
 284 {
 285         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 286         Dwarf_Die type;
 287         char buf[16];
 288         char sbuf[STRERR_BUFSIZE];
 289         int bsize, boffs, total;
 290         int ret;
 291         char prefix;
 292
 293         /* TODO: check all types */
 294         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 295             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 296                 /* Non string type is OK */
 297                 /* and respect signedness/hexadecimal cast */
 298                 tvar->type = strdup(cast);
 299                 return (tvar->type == NULL) ? -ENOMEM : 0;
 300         }
 301
 302         bsize = dwarf_bitsize(vr_die);
 303         if (bsize > 0) {
 304                 /* This is a bitfield */
 305                 boffs = dwarf_bitoffset(vr_die);
 306                 total = dwarf_bytesize(vr_die);
 307                 if (boffs < 0 || total < 0)
 308                         return -ENOENT;
 309                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 310                                 BYTES_TO_BITS(total));
 311                 goto formatted;
 312         }
 313
 314         if (die_get_real_type(vr_die, &type) == NULL) {
 315                 pr_warning("Failed to get a type information of %s.\n",
 316                            dwarf_diename(vr_die));
 317                 return -ENOENT;
 318         }
 319
 320         pr_debug("%s type is %s.\n",
 321                  dwarf_diename(vr_die), dwarf_diename(&type));
 322
 323         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 324                 ret = dwarf_tag(&type);
 325                 if (ret != DW_TAG_pointer_type &&
 326                     ret != DW_TAG_array_type) {
 327                         pr_warning("Failed to cast into string: "
 328                                    "%s(%s) is not a pointer nor array.\n",
 329                                    dwarf_diename(vr_die), dwarf_diename(&type));
 330                         return -EINVAL;
 331                 }
 332                 if (die_get_real_type(&type, &type) == NULL) {
 333                         pr_warning("Failed to get a type"
 334                                    " information.\n");
 335                         return -ENOENT;
 336                 }
 337                 if (ret == DW_TAG_pointer_type) {
 338                         while (*ref_ptr)
 339                                 ref_ptr = &(*ref_ptr)->next;
 340                         /* Add new reference with offset +0 */
 341                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 342                         if (*ref_ptr == NULL) {
 343                                 pr_warning("Out of memory error\n");
 344                                 return -ENOMEM;
 345                         }
 346                 }
 347                 if (!die_compare_name(&type, "char") &&
 348                     !die_compare_name(&type, "unsigned char")) {
 349                         pr_warning("Failed to cast into string: "
 350                                    "%s is not (unsigned) char *.\n",
 351                                    dwarf_diename(vr_die));
 352                         return -EINVAL;
 353                 }
 354                 tvar->type = strdup(cast);
 355                 return (tvar->type == NULL) ? -ENOMEM : 0;
 356         }
 357
 358         if (cast && (strcmp(cast, "u") == 0))
 359                 prefix = 'u';
 360         else if (cast && (strcmp(cast, "s") == 0))
 361                 prefix = 's';
 362         else if (cast && (strcmp(cast, "x") == 0) &&
 363                  probe_type_is_available(PROBE_TYPE_X))
 364                 prefix = 'x';
 365         else
 366                 prefix = die_is_signed_type(&type) ? 's' :
 367                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 368
 369         ret = dwarf_bytesize(&type);
 370         if (ret <= 0)
 371                 /* No size ... try to use default type */
 372                 return 0;
 373         ret = BYTES_TO_BITS(ret);
 374
 375         /* Check the bitwidth */
 376         if (ret > MAX_BASIC_TYPE_BITS) {
 377                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 378                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 379                 ret = MAX_BASIC_TYPE_BITS;
 380         }
 381         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 382
 383 formatted:
 384         if (ret < 0 || ret >= 16) {
 385                 if (ret >= 16)
 386                         ret = -E2BIG;
 387                 pr_warning("Failed to convert variable type: %s\n",
 388                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 389                 return ret;
 390         }
 391         tvar->type = strdup(buf);
 392         if (tvar->type == NULL)
 393                 return -ENOMEM;
 394         return 0;
 395 }
 396
 397 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 398                                     struct perf_probe_arg_field *field,
 399                                     struct probe_trace_arg_ref **ref_ptr,
 400                                     Dwarf_Die *die_mem)
 401 {
 402         struct probe_trace_arg_ref *ref = *ref_ptr;
 403         Dwarf_Die type;
 404         Dwarf_Word offs;
 405         int ret, tag;
 406
 407         pr_debug("converting %s in %s\n", field->name, varname);
 408         if (die_get_real_type(vr_die, &type) == NULL) {
 409                 pr_warning("Failed to get the type of %s.\n", varname);
 410                 return -ENOENT;
 411         }
 412         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 413                   (unsigned)dwarf_dieoffset(&type));
 414         tag = dwarf_tag(&type);
 415
 416         if (field->name[0] == '[' &&
 417             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 418                 /* Save original type for next field or type */
 419                 memcpy(die_mem, &type, sizeof(*die_mem));
 420                 /* Get the type of this array */
 421                 if (die_get_real_type(&type, &type) == NULL) {
 422                         pr_warning("Failed to get the type of %s.\n", varname);
 423                         return -ENOENT;
 424                 }
 425                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 426                          (unsigned)dwarf_dieoffset(&type));
 427                 if (tag == DW_TAG_pointer_type) {
 428                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 429                         if (ref == NULL)
 430                                 return -ENOMEM;
 431                         if (*ref_ptr)
 432                                 (*ref_ptr)->next = ref;
 433                         else
 434                                 *ref_ptr = ref;
 435                 }
 436                 ref->offset += dwarf_bytesize(&type) * field->index;
 437                 goto next;
 438         } else if (tag == DW_TAG_pointer_type) {
 439                 /* Check the pointer and dereference */
 440                 if (!field->ref) {
 441                         pr_err("Semantic error: %s must be referred by '->'\n",
 442                                field->name);
 443                         return -EINVAL;
 444                 }
 445                 /* Get the type pointed by this pointer */
 446                 if (die_get_real_type(&type, &type) == NULL) {
 447                         pr_warning("Failed to get the type of %s.\n", varname);
 448                         return -ENOENT;
 449                 }
 450                 /* Verify it is a data structure  */
 451                 tag = dwarf_tag(&type);
 452                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 453                         pr_warning("%s is not a data structure nor a union.\n",
 454                                    varname);
 455                         return -EINVAL;
 456                 }
 457
 458                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 459                 if (ref == NULL)
 460                         return -ENOMEM;
 461                 if (*ref_ptr)
 462                         (*ref_ptr)->next = ref;
 463                 else
 464                         *ref_ptr = ref;
 465         } else {
 466                 /* Verify it is a data structure  */
 467                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 468                         pr_warning("%s is not a data structure nor a union.\n",
 469                                    varname);
 470                         return -EINVAL;
 471                 }
 472                 if (field->name[0] == '[') {
 473                         pr_err("Semantic error: %s is not a pointer"
 474                                " nor array.\n", varname);
 475                         return -EINVAL;
 476                 }
 477                 /* While prcessing unnamed field, we don't care about this */
 478                 if (field->ref && dwarf_diename(vr_die)) {
 479                         pr_err("Semantic error: %s must be referred by '.'\n",
 480                                field->name);
 481                         return -EINVAL;
 482                 }
 483                 if (!ref) {
 484                         pr_warning("Structure on a register is not "
 485                                    "supported yet.\n");
 486                         return -ENOTSUP;
 487                 }
 488         }
 489
 490         if (die_find_member(&type, field->name, die_mem) == NULL) {
 491                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 492                            dwarf_diename(&type), field->name);
 493                 return -EINVAL;
 494         }
 495
 496         /* Get the offset of the field */
 497         if (tag == DW_TAG_union_type) {
 498                 offs = 0;
 499         } else {
 500                 ret = die_get_data_member_location(die_mem, &offs);
 501                 if (ret < 0) {
 502                         pr_warning("Failed to get the offset of %s.\n",
 503                                    field->name);
 504                         return ret;
 505                 }
 506         }
 507         ref->offset += (long)offs;
 508
 509         /* If this member is unnamed, we need to reuse this field */
 510         if (!dwarf_diename(die_mem))
 511                 return convert_variable_fields(die_mem, varname, field,
 512                                                 &ref, die_mem);
 513
 514 next:
 515         /* Converting next field */
 516         if (field->next)
 517                 return convert_variable_fields(die_mem, field->name,
 518                                         field->next, &ref, die_mem);
 519         else
 520                 return 0;
 521 }
 522
 523 /* Show a variables in kprobe event format */
 524 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 525 {
 526         Dwarf_Die die_mem;
 527         int ret;
 528
 529         pr_debug("Converting variable %s into trace event.\n",
 530                  dwarf_diename(vr_die));
 531
 532         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 533                                         &pf->sp_die, pf->machine, pf->tvar);
 534         if (ret == -ENOENT || ret == -EINVAL) {
 535                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 536                        " Perhaps it has been optimized out.\n"
 537                        " Use -V with the --range option to show '%s' location range.\n",
 538                        pf->pvar->var, pf->pvar->var);
 539         } else if (ret == -ENOTSUP)
 540                 pr_err("Sorry, we don't support this variable location yet.\n");
 541         else if (ret == 0 && pf->pvar->field) {
 542                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 543                                               pf->pvar->field, &pf->tvar->ref,
 544                                               &die_mem);
 545                 vr_die = &die_mem;
 546         }
 547         if (ret == 0)
 548                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 549         /* *expr will be cached in libdw. Don't free it. */
 550         return ret;
 551 }
 552
 553 /* Find a variable in a scope DIE */
 554 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 555 {
 556         Dwarf_Die vr_die;
 557         char *buf, *ptr;
 558         int ret = 0;
 559
 560         /* Copy raw parameters */
 561         if (!is_c_varname(pf->pvar->var))
 562                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 563
 564         if (pf->pvar->name)
 565                 pf->tvar->name = strdup(pf->pvar->name);
 566         else {
 567                 buf = synthesize_perf_probe_arg(pf->pvar);
 568                 if (!buf)
 569                         return -ENOMEM;
 570                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 571                 if (ptr)
 572                         *ptr = '_';
 573                 pf->tvar->name = buf;
 574         }
 575         if (pf->tvar->name == NULL)
 576                 return -ENOMEM;
 577
 578         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 579         /* Search child die for local variables and parameters. */
 580         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 581                 /* Search again in global variables */
 582                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 583                                                 0, &vr_die)) {
 584                         pr_warning("Failed to find '%s' in this function.\n",
 585                                    pf->pvar->var);
 586                         ret = -ENOENT;
 587                 }
 588         }
 589         if (ret >= 0)
 590                 ret = convert_variable(&vr_die, pf);
 591
 592         return ret;
 593 }
 594
 595 /* Convert subprogram DIE to trace point */
 596 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 597                                   Dwarf_Addr paddr, bool retprobe,
 598                                   const char *function,
 599                                   struct probe_trace_point *tp)
 600 {
 601         Dwarf_Addr eaddr, highaddr;
 602         GElf_Sym sym;
 603         const char *symbol;
 604
 605         /* Verify the address is correct */
 606         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 607                 pr_warning("Failed to get entry address of %s\n",
 608                            dwarf_diename(sp_die));
 609                 return -ENOENT;
 610         }
 611         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 612                 pr_warning("Failed to get end address of %s\n",
 613                            dwarf_diename(sp_die));
 614                 return -ENOENT;
 615         }
 616         if (paddr > highaddr) {
 617                 pr_warning("Offset specified is greater than size of %s\n",
 618                            dwarf_diename(sp_die));
 619                 return -EINVAL;
 620         }
 621
 622         symbol = dwarf_diename(sp_die);
 623         if (!symbol) {
 624                 /* Try to get the symbol name from symtab */
 625                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 626                 if (!symbol) {
 627                         pr_warning("Failed to find symbol at 0x%lx\n",
 628                                    (unsigned long)paddr);
 629                         return -ENOENT;
 630                 }
 631                 eaddr = sym.st_value;
 632         }
 633         tp->offset = (unsigned long)(paddr - eaddr);
 634         tp->address = (unsigned long)paddr;
 635         tp->symbol = strdup(symbol);
 636         if (!tp->symbol)
 637                 return -ENOMEM;
 638
 639         /* Return probe must be on the head of a subprogram */
 640         if (retprobe) {
 641                 if (eaddr != paddr) {
 642                         pr_warning("Failed to find \"%s%%return\",\n"
 643                                    " because %s is an inlined function and"
 644                                    " has no return point.\n", function,
 645                                    function);
 646                         return -EINVAL;
 647                 }
 648                 tp->retprobe = true;
 649         }
 650
 651         return 0;
 652 }
 653
 654 /* Call probe_finder callback with scope DIE */
 655 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 656 {
 657         Dwarf_Attribute fb_attr;
 658         Dwarf_Frame *frame = NULL;
 659         size_t nops;
 660         int ret;
 661
 662         if (!sc_die) {
 663                 pr_err("Caller must pass a scope DIE. Program error.\n");
 664                 return -EINVAL;
 665         }
 666
 667         /* If not a real subprogram, find a real one */
 668         if (!die_is_func_def(sc_die)) {
 669                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 670                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 671                                 pr_warning("Ignoring tail call from %s\n",
 672                                                 dwarf_diename(&pf->sp_die));
 673                                 return 0;
 674                         } else {
 675                                 pr_warning("Failed to find probe point in any "
 676                                            "functions.\n");
 677                                 return -ENOENT;
 678                         }
 679                 }
 680         } else
 681                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 682
 683         /* Get the frame base attribute/ops from subprogram */
 684         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 685         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 686         if (ret <= 0 || nops == 0) {
 687                 pf->fb_ops = NULL;
 688 #if _ELFUTILS_PREREQ(0, 142)
 689         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 690                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 691                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 692                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 693                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 694                         pr_warning("Failed to get call frame on 0x%jx\n",
 695                                    (uintmax_t)pf->addr);
 696                         free(frame);
 697                         return -ENOENT;
 698                 }
 699 #endif
 700         }
 701
 702         /* Call finder's callback handler */
 703         ret = pf->callback(sc_die, pf);
 704
 705         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 706         free(frame);
 707         pf->fb_ops = NULL;
 708
 709         return ret;
 710 }
 711
 712 struct find_scope_param {
 713         const char *function;
 714         const char *file;
 715         int line;
 716         int diff;
 717         Dwarf_Die *die_mem;
 718         bool found;
 719 };
 720
 721 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 722 {
 723         struct find_scope_param *fsp = data;
 724         const char *file;
 725         int lno;
 726
 727         /* Skip if declared file name does not match */
 728         if (fsp->file) {
 729                 file = dwarf_decl_file(fn_die);
 730                 if (!file || strcmp(fsp->file, file) != 0)
 731                         return 0;
 732         }
 733         /* If the function name is given, that's what user expects */
 734         if (fsp->function) {
 735                 if (die_match_name(fn_die, fsp->function)) {
 736                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 737                         fsp->found = true;
 738                         return 1;
 739                 }
 740         } else {
 741                 /* With the line number, find the nearest declared DIE */
 742                 dwarf_decl_line(fn_die, &lno);
 743                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 744                         /* Keep a candidate and continue */
 745                         fsp->diff = fsp->line - lno;
 746                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 747                         fsp->found = true;
 748                 }
 749         }
 750         return 0;
 751 }
 752
 753 /* Find an appropriate scope fits to given conditions */
 754 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 755 {
 756         struct find_scope_param fsp = {
 757                 .function = pf->pev->point.function,
 758                 .file = pf->fname,
 759                 .line = pf->lno,
 760                 .diff = INT_MAX,
 761                 .die_mem = die_mem,
 762                 .found = false,
 763         };
 764
 765         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 766
 767         return fsp.found ? die_mem : NULL;
 768 }
 769
 770 static int probe_point_line_walker(const char *fname, int lineno,
 771                                    Dwarf_Addr addr, void *data)
 772 {
 773         struct probe_finder *pf = data;
 774         Dwarf_Die *sc_die, die_mem;
 775         int ret;
 776
 777         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 778                 return 0;
 779
 780         pf->addr = addr;
 781         sc_die = find_best_scope(pf, &die_mem);
 782         if (!sc_die) {
 783                 pr_warning("Failed to find scope of probe point.\n");
 784                 return -ENOENT;
 785         }
 786
 787         ret = call_probe_finder(sc_die, pf);
 788
 789         /* Continue if no error, because the line will be in inline function */
 790         return ret < 0 ? ret : 0;
 791 }
 792
 793 /* Find probe point from its line number */
 794 static int find_probe_point_by_line(struct probe_finder *pf)
 795 {
 796         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 797 }
 798
 799 /* Find lines which match lazy pattern */
 800 static int find_lazy_match_lines(struct intlist *list,
 801                                  const char *fname, const char *pat)
 802 {
 803         FILE *fp;
 804         char *line = NULL;
 805         size_t line_len;
 806         ssize_t len;
 807         int count = 0, linenum = 1;
 808         char sbuf[STRERR_BUFSIZE];
 809
 810         fp = fopen(fname, "r");
 811         if (!fp) {
 812                 pr_warning("Failed to open %s: %s\n", fname,
 813                            str_error_r(errno, sbuf, sizeof(sbuf)));
 814                 return -errno;
 815         }
 816
 817         while ((len = getline(&line, &line_len, fp)) > 0) {
 818
 819                 if (line[len - 1] == '\n')
 820                         line[len - 1] = '\0';
 821
 822                 if (strlazymatch(line, pat)) {
 823                         intlist__add(list, linenum);
 824                         count++;
 825                 }
 826                 linenum++;
 827         }
 828
 829         if (ferror(fp))
 830                 count = -errno;
 831         free(line);
 832         fclose(fp);
 833
 834         if (count == 0)
 835                 pr_debug("No matched lines found in %s.\n", fname);
 836         return count;
 837 }
 838
 839 static int probe_point_lazy_walker(const char *fname, int lineno,
 840                                    Dwarf_Addr addr, void *data)
 841 {
 842         struct probe_finder *pf = data;
 843         Dwarf_Die *sc_die, die_mem;
 844         int ret;
 845
 846         if (!intlist__has_entry(pf->lcache, lineno) ||
 847             strtailcmp(fname, pf->fname) != 0)
 848                 return 0;
 849
 850         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 851                  lineno, (unsigned long long)addr);
 852         pf->addr = addr;
 853         pf->lno = lineno;
 854         sc_die = find_best_scope(pf, &die_mem);
 855         if (!sc_die) {
 856                 pr_warning("Failed to find scope of probe point.\n");
 857                 return -ENOENT;
 858         }
 859
 860         ret = call_probe_finder(sc_die, pf);
 861
 862         /*
 863          * Continue if no error, because the lazy pattern will match
 864          * to other lines
 865          */
 866         return ret < 0 ? ret : 0;
 867 }
 868
 869 /* Find probe points from lazy pattern  */
 870 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 871 {
 872         int ret = 0;
 873         char *fpath;
 874
 875         if (intlist__empty(pf->lcache)) {
 876                 const char *comp_dir;
 877
 878                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 879                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 880                 if (ret < 0) {
 881                         pr_warning("Failed to find source file path.\n");
 882                         return ret;
 883                 }
 884
 885                 /* Matching lazy line pattern */
 886                 ret = find_lazy_match_lines(pf->lcache, fpath,
 887                                             pf->pev->point.lazy_line);
 888                 free(fpath);
 889                 if (ret <= 0)
 890                         return ret;
 891         }
 892
 893         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 894 }
 895
 896 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 897 {
 898         struct perf_probe_point *pp = &pf->pev->point;
 899
 900         /* Not uprobe? */
 901         if (!pf->pev->uprobes)
 902                 return;
 903
 904         /* Compiled with optimization? */
 905         if (die_is_optimized_target(&pf->cu_die))
 906                 return;
 907
 908         /* Don't know entrypc? */
 909         if (!pf->addr)
 910                 return;
 911
 912         /* Only FUNC and FUNC@SRC are eligible. */
 913         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 914             pp->offset || pp->abs_address)
 915                 return;
 916
 917         /* Not interested in func parameter? */
 918         if (!perf_probe_with_var(pf->pev))
 919                 return;
 920
 921         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 922                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 923                 pf->addr);
 924
 925         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 926 }
 927
 928 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 929 {
 930         struct probe_finder *pf = data;
 931         struct perf_probe_point *pp = &pf->pev->point;
 932         Dwarf_Addr addr;
 933         int ret;
 934
 935         if (pp->lazy_line)
 936                 ret = find_probe_point_lazy(in_die, pf);
 937         else {
 938                 /* Get probe address */
 939                 if (dwarf_entrypc(in_die, &addr) != 0) {
 940                         pr_warning("Failed to get entry address of %s.\n",
 941                                    dwarf_diename(in_die));
 942                         return -ENOENT;
 943                 }
 944                 if (addr == 0) {
 945                         pr_debug("%s has no valid entry address. skipped.\n",
 946                                  dwarf_diename(in_die));
 947                         return -ENOENT;
 948                 }
 949                 pf->addr = addr;
 950                 pf->addr += pp->offset;
 951                 pr_debug("found inline addr: 0x%jx\n",
 952                          (uintmax_t)pf->addr);
 953
 954                 ret = call_probe_finder(in_die, pf);
 955         }
 956
 957         return ret;
 958 }
 959
 960 /* Callback parameter with return value for libdw */
 961 struct dwarf_callback_param {
 962         void *data;
 963         int retval;
 964 };
 965
 966 /* Search function from function name */
 967 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 968 {
 969         struct dwarf_callback_param *param = data;
 970         struct probe_finder *pf = param->data;
 971         struct perf_probe_point *pp = &pf->pev->point;
 972
 973         /* Check tag and diename */
 974         if (!die_is_func_def(sp_die) ||
 975             !die_match_name(sp_die, pp->function))
 976                 return DWARF_CB_OK;
 977
 978         /* Check declared file */
 979         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 980                 return DWARF_CB_OK;
 981
 982         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
 983                  (unsigned long)dwarf_dieoffset(sp_die));
 984         pf->fname = dwarf_decl_file(sp_die);
 985         if (pp->line) { /* Function relative line */
 986                 dwarf_decl_line(sp_die, &pf->lno);
 987                 pf->lno += pp->line;
 988                 param->retval = find_probe_point_by_line(pf);
 989         } else if (die_is_func_instance(sp_die)) {
 990                 /* Instances always have the entry address */
 991                 dwarf_entrypc(sp_die, &pf->addr);
 992                 /* But in some case the entry address is 0 */
 993                 if (pf->addr == 0) {
 994                         pr_debug("%s has no entry PC. Skipped\n",
 995                                  dwarf_diename(sp_die));
 996                         param->retval = 0;
 997                 /* Real function */
 998                 } else if (pp->lazy_line)
 999                         param->retval = find_probe_point_lazy(sp_die, pf);
1000                 else {
1001                         skip_prologue(sp_die, pf);
1002                         pf->addr += pp->offset;
1003                         /* TODO: Check the address in this function */
1004                         param->retval = call_probe_finder(sp_die, pf);
1005                 }
1006         } else if (!probe_conf.no_inlines) {
1007                 /* Inlined function: search instances */
1008                 param->retval = die_walk_instances(sp_die,
1009                                         probe_point_inline_cb, (void *)pf);
1010                 /* This could be a non-existed inline definition */
1011                 if (param->retval == -ENOENT)
1012                         param->retval = 0;
1013         }
1014
1015         /* We need to find other candidates */
1016         if (strisglob(pp->function) && param->retval >= 0) {
1017                 param->retval = 0;      /* We have to clear the result */
1018                 return DWARF_CB_OK;
1019         }
1020
1021         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1022 }
1023
1024 static int find_probe_point_by_func(struct probe_finder *pf)
1025 {
1026         struct dwarf_callback_param _param = {.data = (void *)pf,
1027                                               .retval = 0};
1028         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1029         return _param.retval;
1030 }
1031
1032 struct pubname_callback_param {
1033         char *function;
1034         char *file;
1035         Dwarf_Die *cu_die;
1036         Dwarf_Die *sp_die;
1037         int found;
1038 };
1039
1040 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1041 {
1042         struct pubname_callback_param *param = data;
1043
1044         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1045                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1046                         return DWARF_CB_OK;
1047
1048                 if (die_match_name(param->sp_die, param->function)) {
1049                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1050                                 return DWARF_CB_OK;
1051
1052                         if (param->file &&
1053                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1054                                 return DWARF_CB_OK;
1055
1056                         param->found = 1;
1057                         return DWARF_CB_ABORT;
1058                 }
1059         }
1060
1061         return DWARF_CB_OK;
1062 }
1063
1064 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1065                                   struct probe_finder *pf)
1066 {
1067         struct perf_probe_point *pp = &pf->pev->point;
1068         Dwarf_Off off, noff;
1069         size_t cuhl;
1070         Dwarf_Die *diep;
1071         int ret = 0;
1072
1073         off = 0;
1074         pf->lcache = intlist__new(NULL);
1075         if (!pf->lcache)
1076                 return -ENOMEM;
1077
1078         /* Fastpath: lookup by function name from .debug_pubnames section */
1079         if (pp->function && !strisglob(pp->function)) {
1080                 struct pubname_callback_param pubname_param = {
1081                         .function = pp->function,
1082                         .file     = pp->file,
1083                         .cu_die   = &pf->cu_die,
1084                         .sp_die   = &pf->sp_die,
1085                         .found    = 0,
1086                 };
1087                 struct dwarf_callback_param probe_param = {
1088                         .data = pf,
1089                 };
1090
1091                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1092                                   &pubname_param, 0);
1093                 if (pubname_param.found) {
1094                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1095                         if (ret)
1096                                 goto found;
1097                 }
1098         }
1099
1100         /* Loop on CUs (Compilation Unit) */
1101         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1102                 /* Get the DIE(Debugging Information Entry) of this CU */
1103                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1104                 if (!diep)
1105                         continue;
1106
1107                 /* Check if target file is included. */
1108                 if (pp->file)
1109                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1110                 else
1111                         pf->fname = NULL;
1112
1113                 if (!pp->file || pf->fname) {
1114                         if (pp->function)
1115                                 ret = find_probe_point_by_func(pf);
1116                         else if (pp->lazy_line)
1117                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1118                         else {
1119                                 pf->lno = pp->line;
1120                                 ret = find_probe_point_by_line(pf);
1121                         }
1122                         if (ret < 0)
1123                                 break;
1124                 }
1125                 off = noff;
1126         }
1127
1128 found:
1129         intlist__delete(pf->lcache);
1130         pf->lcache = NULL;
1131
1132         return ret;
1133 }
1134
1135 /* Find probe points from debuginfo */
1136 static int debuginfo__find_probes(struct debuginfo *dbg,
1137                                   struct probe_finder *pf)
1138 {
1139         int ret = 0;
1140         Elf *elf;
1141         GElf_Ehdr ehdr;
1142
1143         if (pf->cfi_eh || pf->cfi_dbg)
1144                 return debuginfo__find_probe_location(dbg, pf);
1145
1146         /* Get the call frame information from this dwarf */
1147         elf = dwarf_getelf(dbg->dbg);
1148         if (elf == NULL)
1149                 return -EINVAL;
1150
1151         if (gelf_getehdr(elf, &ehdr) == NULL)
1152                 return -EINVAL;
1153
1154         pf->machine = ehdr.e_machine;
1155
1156 #if _ELFUTILS_PREREQ(0, 142)
1157         do {
1158                 GElf_Shdr shdr;
1159
1160                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1161                     shdr.sh_type == SHT_PROGBITS)
1162                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1163
1164                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1165         } while (0);
1166 #endif
1167
1168         ret = debuginfo__find_probe_location(dbg, pf);
1169         return ret;
1170 }
1171
1172 struct local_vars_finder {
1173         struct probe_finder *pf;
1174         struct perf_probe_arg *args;
1175         bool vars;
1176         int max_args;
1177         int nargs;
1178         int ret;
1179 };
1180
1181 /* Collect available variables in this scope */
1182 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1183 {
1184         struct local_vars_finder *vf = data;
1185         struct probe_finder *pf = vf->pf;
1186         int tag;
1187
1188         tag = dwarf_tag(die_mem);
1189         if (tag == DW_TAG_formal_parameter ||
1190             (tag == DW_TAG_variable && vf->vars)) {
1191                 if (convert_variable_location(die_mem, vf->pf->addr,
1192                                               vf->pf->fb_ops, &pf->sp_die,
1193                                               pf->machine, NULL) == 0) {
1194                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1195                         if (vf->args[vf->nargs].var == NULL) {
1196                                 vf->ret = -ENOMEM;
1197                                 return DIE_FIND_CB_END;
1198                         }
1199                         pr_debug(" %s", vf->args[vf->nargs].var);
1200                         vf->nargs++;
1201                 }
1202         }
1203
1204         if (dwarf_haspc(die_mem, vf->pf->addr))
1205                 return DIE_FIND_CB_CONTINUE;
1206         else
1207                 return DIE_FIND_CB_SIBLING;
1208 }
1209
1210 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1211                              struct perf_probe_arg *args)
1212 {
1213         Dwarf_Die die_mem;
1214         int i;
1215         int n = 0;
1216         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1217                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1218
1219         for (i = 0; i < pf->pev->nargs; i++) {
1220                 /* var never be NULL */
1221                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1222                         vf.vars = true;
1223                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1224                         /* Copy normal argument */
1225                         args[n] = pf->pev->args[i];
1226                         n++;
1227                         continue;
1228                 }
1229                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1230                 vf.nargs = n;
1231                 /* Special local variables */
1232                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1233                                &die_mem);
1234                 pr_debug(" (%d)\n", vf.nargs - n);
1235                 if (vf.ret < 0)
1236                         return vf.ret;
1237                 n = vf.nargs;
1238         }
1239         return n;
1240 }
1241
1242 /* Add a found probe point into trace event list */
1243 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1244 {
1245         struct trace_event_finder *tf =
1246                         container_of(pf, struct trace_event_finder, pf);
1247         struct perf_probe_point *pp = &pf->pev->point;
1248         struct probe_trace_event *tev;
1249         struct perf_probe_arg *args = NULL;
1250         int ret, i;
1251
1252         /* Check number of tevs */
1253         if (tf->ntevs == tf->max_tevs) {
1254                 pr_warning("Too many( > %d) probe point found.\n",
1255                            tf->max_tevs);
1256                 return -ERANGE;
1257         }
1258         tev = &tf->tevs[tf->ntevs++];
1259
1260         /* Trace point should be converted from subprogram DIE */
1261         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1262                                      pp->retprobe, pp->function, &tev->point);
1263         if (ret < 0)
1264                 goto end;
1265
1266         tev->point.realname = strdup(dwarf_diename(sc_die));
1267         if (!tev->point.realname) {
1268                 ret = -ENOMEM;
1269                 goto end;
1270         }
1271
1272         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1273                  tev->point.offset);
1274
1275         /* Expand special probe argument if exist */
1276         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1277         if (args == NULL) {
1278                 ret = -ENOMEM;
1279                 goto end;
1280         }
1281
1282         ret = expand_probe_args(sc_die, pf, args);
1283         if (ret < 0)
1284                 goto end;
1285
1286         tev->nargs = ret;
1287         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1288         if (tev->args == NULL) {
1289                 ret = -ENOMEM;
1290                 goto end;
1291         }
1292
1293         /* Find each argument */
1294         for (i = 0; i < tev->nargs; i++) {
1295                 pf->pvar = &args[i];
1296                 pf->tvar = &tev->args[i];
1297                 /* Variable should be found from scope DIE */
1298                 ret = find_variable(sc_die, pf);
1299                 if (ret != 0)
1300                         break;
1301         }
1302
1303 end:
1304         if (ret) {
1305                 clear_probe_trace_event(tev);
1306                 tf->ntevs--;
1307         }
1308         free(args);
1309         return ret;
1310 }
1311
1312 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1313 int debuginfo__find_trace_events(struct debuginfo *dbg,
1314                                  struct perf_probe_event *pev,
1315                                  struct probe_trace_event **tevs)
1316 {
1317         struct trace_event_finder tf = {
1318                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1319                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1320         int ret, i;
1321
1322         /* Allocate result tevs array */
1323         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1324         if (*tevs == NULL)
1325                 return -ENOMEM;
1326
1327         tf.tevs = *tevs;
1328         tf.ntevs = 0;
1329
1330         ret = debuginfo__find_probes(dbg, &tf.pf);
1331         if (ret < 0) {
1332                 for (i = 0; i < tf.ntevs; i++)
1333                         clear_probe_trace_event(&tf.tevs[i]);
1334                 zfree(tevs);
1335                 return ret;
1336         }
1337
1338         return (ret < 0) ? ret : tf.ntevs;
1339 }
1340
1341 /* Collect available variables in this scope */
1342 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1343 {
1344         struct available_var_finder *af = data;
1345         struct variable_list *vl;
1346         struct strbuf buf = STRBUF_INIT;
1347         int tag, ret;
1348
1349         vl = &af->vls[af->nvls - 1];
1350
1351         tag = dwarf_tag(die_mem);
1352         if (tag == DW_TAG_formal_parameter ||
1353             tag == DW_TAG_variable) {
1354                 ret = convert_variable_location(die_mem, af->pf.addr,
1355                                                 af->pf.fb_ops, &af->pf.sp_die,
1356                                                 af->pf.machine, NULL);
1357                 if (ret == 0 || ret == -ERANGE) {
1358                         int ret2;
1359                         bool externs = !af->child;
1360
1361                         if (strbuf_init(&buf, 64) < 0)
1362                                 goto error;
1363
1364                         if (probe_conf.show_location_range) {
1365                                 if (!externs)
1366                                         ret2 = strbuf_add(&buf,
1367                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1368                                 else
1369                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1370                                 if (ret2)
1371                                         goto error;
1372                         }
1373
1374                         ret2 = die_get_varname(die_mem, &buf);
1375
1376                         if (!ret2 && probe_conf.show_location_range &&
1377                                 !externs) {
1378                                 if (strbuf_addch(&buf, '\t') < 0)
1379                                         goto error;
1380                                 ret2 = die_get_var_range(&af->pf.sp_die,
1381                                                         die_mem, &buf);
1382                         }
1383
1384                         pr_debug("Add new var: %s\n", buf.buf);
1385                         if (ret2 == 0) {
1386                                 strlist__add(vl->vars,
1387                                         strbuf_detach(&buf, NULL));
1388                         }
1389                         strbuf_release(&buf);
1390                 }
1391         }
1392
1393         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1394                 return DIE_FIND_CB_CONTINUE;
1395         else
1396                 return DIE_FIND_CB_SIBLING;
1397 error:
1398         strbuf_release(&buf);
1399         pr_debug("Error in strbuf\n");
1400         return DIE_FIND_CB_END;
1401 }
1402
1403 /* Add a found vars into available variables list */
1404 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1405 {
1406         struct available_var_finder *af =
1407                         container_of(pf, struct available_var_finder, pf);
1408         struct perf_probe_point *pp = &pf->pev->point;
1409         struct variable_list *vl;
1410         Dwarf_Die die_mem;
1411         int ret;
1412
1413         /* Check number of tevs */
1414         if (af->nvls == af->max_vls) {
1415                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1416                 return -ERANGE;
1417         }
1418         vl = &af->vls[af->nvls++];
1419
1420         /* Trace point should be converted from subprogram DIE */
1421         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1422                                      pp->retprobe, pp->function, &vl->point);
1423         if (ret < 0)
1424                 return ret;
1425
1426         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1427                  vl->point.offset);
1428
1429         /* Find local variables */
1430         vl->vars = strlist__new(NULL, NULL);
1431         if (vl->vars == NULL)
1432                 return -ENOMEM;
1433         af->child = true;
1434         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1435
1436         /* Find external variables */
1437         if (!probe_conf.show_ext_vars)
1438                 goto out;
1439         /* Don't need to search child DIE for external vars. */
1440         af->child = false;
1441         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1442
1443 out:
1444         if (strlist__empty(vl->vars)) {
1445                 strlist__delete(vl->vars);
1446                 vl->vars = NULL;
1447         }
1448
1449         return ret;
1450 }
1451
1452 /*
1453  * Find available variables at given probe point
1454  * Return the number of found probe points. Return 0 if there is no
1455  * matched probe point. Return <0 if an error occurs.
1456  */
1457 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1458                                       struct perf_probe_event *pev,
1459                                       struct variable_list **vls)
1460 {
1461         struct available_var_finder af = {
1462                         .pf = {.pev = pev, .callback = add_available_vars},
1463                         .mod = dbg->mod,
1464                         .max_vls = probe_conf.max_probes};
1465         int ret;
1466
1467         /* Allocate result vls array */
1468         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1469         if (*vls == NULL)
1470                 return -ENOMEM;
1471
1472         af.vls = *vls;
1473         af.nvls = 0;
1474
1475         ret = debuginfo__find_probes(dbg, &af.pf);
1476         if (ret < 0) {
1477                 /* Free vlist for error */
1478                 while (af.nvls--) {
1479                         zfree(&af.vls[af.nvls].point.symbol);
1480                         strlist__delete(af.vls[af.nvls].vars);
1481                 }
1482                 zfree(vls);
1483                 return ret;
1484         }
1485
1486         return (ret < 0) ? ret : af.nvls;
1487 }
1488
1489 /* For the kernel module, we need a special code to get a DIE */
1490 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1491                                 bool adjust_offset)
1492 {
1493         int n, i;
1494         Elf32_Word shndx;
1495         Elf_Scn *scn;
1496         Elf *elf;
1497         GElf_Shdr mem, *shdr;
1498         const char *p;
1499
1500         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1501         if (!elf)
1502                 return -EINVAL;
1503
1504         /* Get the number of relocations */
1505         n = dwfl_module_relocations(dbg->mod);
1506         if (n < 0)
1507                 return -ENOENT;
1508         /* Search the relocation related .text section */
1509         for (i = 0; i < n; i++) {
1510                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1511                 if (strcmp(p, ".text") == 0) {
1512                         /* OK, get the section header */
1513                         scn = elf_getscn(elf, shndx);
1514                         if (!scn)
1515                                 return -ENOENT;
1516                         shdr = gelf_getshdr(scn, &mem);
1517                         if (!shdr)
1518                                 return -ENOENT;
1519                         *offs = shdr->sh_addr;
1520                         if (adjust_offset)
1521                                 *offs -= shdr->sh_offset;
1522                 }
1523         }
1524         return 0;
1525 }
1526
1527 /* Reverse search */
1528 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1529                                 struct perf_probe_point *ppt)
1530 {
1531         Dwarf_Die cudie, spdie, indie;
1532         Dwarf_Addr _addr = 0, baseaddr = 0;
1533         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1534         int baseline = 0, lineno = 0, ret = 0;
1535
1536         /* We always need to relocate the address for aranges */
1537         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1538                 addr += baseaddr;
1539         /* Find cu die */
1540         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1541                 pr_warning("Failed to find debug information for address %lx\n",
1542                            addr);
1543                 ret = -EINVAL;
1544                 goto end;
1545         }
1546
1547         /* Find a corresponding line (filename and lineno) */
1548         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1549         /* Don't care whether it failed or not */
1550
1551         /* Find a corresponding function (name, baseline and baseaddr) */
1552         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1553                 /* Get function entry information */
1554                 func = basefunc = dwarf_diename(&spdie);
1555                 if (!func ||
1556                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1557                     dwarf_decl_line(&spdie, &baseline) != 0) {
1558                         lineno = 0;
1559                         goto post;
1560                 }
1561
1562                 fname = dwarf_decl_file(&spdie);
1563                 if (addr == (unsigned long)baseaddr) {
1564                         /* Function entry - Relative line number is 0 */
1565                         lineno = baseline;
1566                         goto post;
1567                 }
1568
1569                 /* Track down the inline functions step by step */
1570                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1571                                                 &indie)) {
1572                         /* There is an inline function */
1573                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1574                             _addr == addr) {
1575                                 /*
1576                                  * addr is at an inline function entry.
1577                                  * In this case, lineno should be the call-site
1578                                  * line number. (overwrite lineinfo)
1579                                  */
1580                                 lineno = die_get_call_lineno(&indie);
1581                                 fname = die_get_call_file(&indie);
1582                                 break;
1583                         } else {
1584                                 /*
1585                                  * addr is in an inline function body.
1586                                  * Since lineno points one of the lines
1587                                  * of the inline function, baseline should
1588                                  * be the entry line of the inline function.
1589                                  */
1590                                 tmp = dwarf_diename(&indie);
1591                                 if (!tmp ||
1592                                     dwarf_decl_line(&indie, &baseline) != 0)
1593                                         break;
1594                                 func = tmp;
1595                                 spdie = indie;
1596                         }
1597                 }
1598                 /* Verify the lineno and baseline are in a same file */
1599                 tmp = dwarf_decl_file(&spdie);
1600                 if (!tmp || strcmp(tmp, fname) != 0)
1601                         lineno = 0;
1602         }
1603
1604 post:
1605         /* Make a relative line number or an offset */
1606         if (lineno)
1607                 ppt->line = lineno - baseline;
1608         else if (basefunc) {
1609                 ppt->offset = addr - (unsigned long)baseaddr;
1610                 func = basefunc;
1611         }
1612
1613         /* Duplicate strings */
1614         if (func) {
1615                 ppt->function = strdup(func);
1616                 if (ppt->function == NULL) {
1617                         ret = -ENOMEM;
1618                         goto end;
1619                 }
1620         }
1621         if (fname) {
1622                 ppt->file = strdup(fname);
1623                 if (ppt->file == NULL) {
1624                         zfree(&ppt->function);
1625                         ret = -ENOMEM;
1626                         goto end;
1627                 }
1628         }
1629 end:
1630         if (ret == 0 && (fname || func))
1631                 ret = 1;        /* Found a point */
1632         return ret;
1633 }
1634
1635 /* Add a line and store the src path */
1636 static int line_range_add_line(const char *src, unsigned int lineno,
1637                                struct line_range *lr)
1638 {
1639         /* Copy source path */
1640         if (!lr->path) {
1641                 lr->path = strdup(src);
1642                 if (lr->path == NULL)
1643                         return -ENOMEM;
1644         }
1645         return intlist__add(lr->line_list, lineno);
1646 }
1647
1648 static int line_range_walk_cb(const char *fname, int lineno,
1649                               Dwarf_Addr addr __maybe_unused,
1650                               void *data)
1651 {
1652         struct line_finder *lf = data;
1653         int err;
1654
1655         if ((strtailcmp(fname, lf->fname) != 0) ||
1656             (lf->lno_s > lineno || lf->lno_e < lineno))
1657                 return 0;
1658
1659         err = line_range_add_line(fname, lineno, lf->lr);
1660         if (err < 0 && err != -EEXIST)
1661                 return err;
1662
1663         return 0;
1664 }
1665
1666 /* Find line range from its line number */
1667 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1668 {
1669         int ret;
1670
1671         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1672
1673         /* Update status */
1674         if (ret >= 0)
1675                 if (!intlist__empty(lf->lr->line_list))
1676                         ret = lf->found = 1;
1677                 else
1678                         ret = 0;        /* Lines are not found */
1679         else {
1680                 zfree(&lf->lr->path);
1681         }
1682         return ret;
1683 }
1684
1685 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1686 {
1687         int ret = find_line_range_by_line(in_die, data);
1688
1689         /*
1690          * We have to check all instances of inlined function, because
1691          * some execution paths can be optimized out depends on the
1692          * function argument of instances. However, if an error occurs,
1693          * it should be handled by the caller.
1694          */
1695         return ret < 0 ? ret : 0;
1696 }
1697
1698 /* Search function definition from function name */
1699 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1700 {
1701         struct dwarf_callback_param *param = data;
1702         struct line_finder *lf = param->data;
1703         struct line_range *lr = lf->lr;
1704
1705         /* Check declared file */
1706         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1707                 return DWARF_CB_OK;
1708
1709         if (die_is_func_def(sp_die) &&
1710             die_match_name(sp_die, lr->function)) {
1711                 lf->fname = dwarf_decl_file(sp_die);
1712                 dwarf_decl_line(sp_die, &lr->offset);
1713                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1714                 lf->lno_s = lr->offset + lr->start;
1715                 if (lf->lno_s < 0)      /* Overflow */
1716                         lf->lno_s = INT_MAX;
1717                 lf->lno_e = lr->offset + lr->end;
1718                 if (lf->lno_e < 0)      /* Overflow */
1719                         lf->lno_e = INT_MAX;
1720                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1721                 lr->start = lf->lno_s;
1722                 lr->end = lf->lno_e;
1723                 if (!die_is_func_instance(sp_die))
1724                         param->retval = die_walk_instances(sp_die,
1725                                                 line_range_inline_cb, lf);
1726                 else
1727                         param->retval = find_line_range_by_line(sp_die, lf);
1728                 return DWARF_CB_ABORT;
1729         }
1730         return DWARF_CB_OK;
1731 }
1732
1733 static int find_line_range_by_func(struct line_finder *lf)
1734 {
1735         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1736         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1737         return param.retval;
1738 }
1739
1740 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1741 {
1742         struct line_finder lf = {.lr = lr, .found = 0};
1743         int ret = 0;
1744         Dwarf_Off off = 0, noff;
1745         size_t cuhl;
1746         Dwarf_Die *diep;
1747         const char *comp_dir;
1748
1749         /* Fastpath: lookup by function name from .debug_pubnames section */
1750         if (lr->function) {
1751                 struct pubname_callback_param pubname_param = {
1752                         .function = lr->function, .file = lr->file,
1753                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1754                 struct dwarf_callback_param line_range_param = {
1755                         .data = (void *)&lf, .retval = 0};
1756
1757                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1758                                   &pubname_param, 0);
1759                 if (pubname_param.found) {
1760                         line_range_search_cb(&lf.sp_die, &line_range_param);
1761                         if (lf.found)
1762                                 goto found;
1763                 }
1764         }
1765
1766         /* Loop on CUs (Compilation Unit) */
1767         while (!lf.found && ret >= 0) {
1768                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1769                                  NULL, NULL, NULL) != 0)
1770                         break;
1771
1772                 /* Get the DIE(Debugging Information Entry) of this CU */
1773                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1774                 if (!diep)
1775                         continue;
1776
1777                 /* Check if target file is included. */
1778                 if (lr->file)
1779                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1780                 else
1781                         lf.fname = 0;
1782
1783                 if (!lr->file || lf.fname) {
1784                         if (lr->function)
1785                                 ret = find_line_range_by_func(&lf);
1786                         else {
1787                                 lf.lno_s = lr->start;
1788                                 lf.lno_e = lr->end;
1789                                 ret = find_line_range_by_line(NULL, &lf);
1790                         }
1791                 }
1792                 off = noff;
1793         }
1794
1795 found:
1796         /* Store comp_dir */
1797         if (lf.found) {
1798                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1799                 if (comp_dir) {
1800                         lr->comp_dir = strdup(comp_dir);
1801                         if (!lr->comp_dir)
1802                                 ret = -ENOMEM;
1803                 }
1804         }
1805
1806         pr_debug("path: %s\n", lr->path);
1807         return (ret < 0) ? ret : lf.found;
1808 }
1809
1810 /*
1811  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1812  * and chop off leading directories that do not exist. Result is passed back as
1813  * a newly allocated path on success.
1814  * Return 0 if file was found and readable, -errno otherwise.
1815  */
1816 int get_real_path(const char *raw_path, const char *comp_dir,
1817                          char **new_path)
1818 {
1819         const char *prefix = symbol_conf.source_prefix;
1820
1821         if (!prefix) {
1822                 if (raw_path[0] != '/' && comp_dir)
1823                         /* If not an absolute path, try to use comp_dir */
1824                         prefix = comp_dir;
1825                 else {
1826                         if (access(raw_path, R_OK) == 0) {
1827                                 *new_path = strdup(raw_path);
1828                                 return *new_path ? 0 : -ENOMEM;
1829                         } else
1830                                 return -errno;
1831                 }
1832         }
1833
1834         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1835         if (!*new_path)
1836                 return -ENOMEM;
1837
1838         for (;;) {
1839                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1840
1841                 if (access(*new_path, R_OK) == 0)
1842                         return 0;
1843
1844                 if (!symbol_conf.source_prefix) {
1845                         /* In case of searching comp_dir, don't retry */
1846                         zfree(new_path);
1847                         return -errno;
1848                 }
1849
1850                 switch (errno) {
1851                 case ENAMETOOLONG:
1852                 case ENOENT:
1853                 case EROFS:
1854                 case EFAULT:
1855                         raw_path = strchr(++raw_path, '/');
1856                         if (!raw_path) {
1857                                 zfree(new_path);
1858                                 return -ENOENT;
1859                         }
1860                         continue;
1861
1862                 default:
1863                         zfree(new_path);
1864                         return -errno;
1865                 }
1866         }
1867 }