linux/tools/perf/util/symbol-elf.c
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   1// SPDX-License-Identifier: GPL-2.0
   2#include <fcntl.h>
   3#include <stdio.h>
   4#include <errno.h>
   5#include <stdlib.h>
   6#include <string.h>
   7#include <unistd.h>
   8#include <inttypes.h>
   9
  10#include "dso.h"
  11#include "map.h"
  12#include "map_groups.h"
  13#include "symbol.h"
  14#include "symsrc.h"
  15#include "demangle-java.h"
  16#include "demangle-rust.h"
  17#include "machine.h"
  18#include "vdso.h"
  19#include "debug.h"
  20#include "util/copyfile.h"
  21#include <linux/ctype.h>
  22#include <linux/kernel.h>
  23#include <linux/zalloc.h>
  24#include <symbol/kallsyms.h>
  25#include <internal/lib.h>
  26
  27#ifndef EM_AARCH64
  28#define EM_AARCH64      183  /* ARM 64 bit */
  29#endif
  30
  31#ifndef ELF32_ST_VISIBILITY
  32#define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  33#endif
  34
  35/* For ELF64 the definitions are the same.  */
  36#ifndef ELF64_ST_VISIBILITY
  37#define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  38#endif
  39
  40/* How to extract information held in the st_other field.  */
  41#ifndef GELF_ST_VISIBILITY
  42#define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  43#endif
  44
  45typedef Elf64_Nhdr GElf_Nhdr;
  46
  47#ifndef DMGL_PARAMS
  48#define DMGL_NO_OPTS     0              /* For readability... */
  49#define DMGL_PARAMS      (1 << 0)       /* Include function args */
  50#define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  51#endif
  52
  53#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  54extern char *cplus_demangle(const char *, int);
  55
  56static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  57{
  58        return cplus_demangle(c, i);
  59}
  60#else
  61#ifdef NO_DEMANGLE
  62static inline char *bfd_demangle(void __maybe_unused *v,
  63                                 const char __maybe_unused *c,
  64                                 int __maybe_unused i)
  65{
  66        return NULL;
  67}
  68#else
  69#define PACKAGE 'perf'
  70#include <bfd.h>
  71#endif
  72#endif
  73
  74#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  75static int elf_getphdrnum(Elf *elf, size_t *dst)
  76{
  77        GElf_Ehdr gehdr;
  78        GElf_Ehdr *ehdr;
  79
  80        ehdr = gelf_getehdr(elf, &gehdr);
  81        if (!ehdr)
  82                return -1;
  83
  84        *dst = ehdr->e_phnum;
  85
  86        return 0;
  87}
  88#endif
  89
  90#ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  91static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  92{
  93        pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  94        return -1;
  95}
  96#endif
  97
  98#ifndef NT_GNU_BUILD_ID
  99#define NT_GNU_BUILD_ID 3
 100#endif
 101
 102/**
 103 * elf_symtab__for_each_symbol - iterate thru all the symbols
 104 *
 105 * @syms: struct elf_symtab instance to iterate
 106 * @idx: uint32_t idx
 107 * @sym: GElf_Sym iterator
 108 */
 109#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 110        for (idx = 0, gelf_getsym(syms, idx, &sym);\
 111             idx < nr_syms; \
 112             idx++, gelf_getsym(syms, idx, &sym))
 113
 114static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 115{
 116        return GELF_ST_TYPE(sym->st_info);
 117}
 118
 119static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 120{
 121        return GELF_ST_VISIBILITY(sym->st_other);
 122}
 123
 124#ifndef STT_GNU_IFUNC
 125#define STT_GNU_IFUNC 10
 126#endif
 127
 128static inline int elf_sym__is_function(const GElf_Sym *sym)
 129{
 130        return (elf_sym__type(sym) == STT_FUNC ||
 131                elf_sym__type(sym) == STT_GNU_IFUNC) &&
 132               sym->st_name != 0 &&
 133               sym->st_shndx != SHN_UNDEF;
 134}
 135
 136static inline bool elf_sym__is_object(const GElf_Sym *sym)
 137{
 138        return elf_sym__type(sym) == STT_OBJECT &&
 139                sym->st_name != 0 &&
 140                sym->st_shndx != SHN_UNDEF;
 141}
 142
 143static inline int elf_sym__is_label(const GElf_Sym *sym)
 144{
 145        return elf_sym__type(sym) == STT_NOTYPE &&
 146                sym->st_name != 0 &&
 147                sym->st_shndx != SHN_UNDEF &&
 148                sym->st_shndx != SHN_ABS &&
 149                elf_sym__visibility(sym) != STV_HIDDEN &&
 150                elf_sym__visibility(sym) != STV_INTERNAL;
 151}
 152
 153static bool elf_sym__filter(GElf_Sym *sym)
 154{
 155        return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 156}
 157
 158static inline const char *elf_sym__name(const GElf_Sym *sym,
 159                                        const Elf_Data *symstrs)
 160{
 161        return symstrs->d_buf + sym->st_name;
 162}
 163
 164static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 165                                        const Elf_Data *secstrs)
 166{
 167        return secstrs->d_buf + shdr->sh_name;
 168}
 169
 170static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 171                                        const Elf_Data *secstrs)
 172{
 173        return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 174}
 175
 176static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 177                                    const Elf_Data *secstrs)
 178{
 179        return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 180}
 181
 182static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 183{
 184        return elf_sec__is_text(shdr, secstrs) || 
 185               elf_sec__is_data(shdr, secstrs);
 186}
 187
 188static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 189{
 190        Elf_Scn *sec = NULL;
 191        GElf_Shdr shdr;
 192        size_t cnt = 1;
 193
 194        while ((sec = elf_nextscn(elf, sec)) != NULL) {
 195                gelf_getshdr(sec, &shdr);
 196
 197                if ((addr >= shdr.sh_addr) &&
 198                    (addr < (shdr.sh_addr + shdr.sh_size)))
 199                        return cnt;
 200
 201                ++cnt;
 202        }
 203
 204        return -1;
 205}
 206
 207Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 208                             GElf_Shdr *shp, const char *name, size_t *idx)
 209{
 210        Elf_Scn *sec = NULL;
 211        size_t cnt = 1;
 212
 213        /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 214        if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 215                return NULL;
 216
 217        while ((sec = elf_nextscn(elf, sec)) != NULL) {
 218                char *str;
 219
 220                gelf_getshdr(sec, shp);
 221                str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 222                if (str && !strcmp(name, str)) {
 223                        if (idx)
 224                                *idx = cnt;
 225                        return sec;
 226                }
 227                ++cnt;
 228        }
 229
 230        return NULL;
 231}
 232
 233static bool want_demangle(bool is_kernel_sym)
 234{
 235        return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 236}
 237
 238static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 239{
 240        int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 241        char *demangled = NULL;
 242
 243        /*
 244         * We need to figure out if the object was created from C++ sources
 245         * DWARF DW_compile_unit has this, but we don't always have access
 246         * to it...
 247         */
 248        if (!want_demangle(dso->kernel || kmodule))
 249            return demangled;
 250
 251        demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 252        if (demangled == NULL)
 253                demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 254        else if (rust_is_mangled(demangled))
 255                /*
 256                    * Input to Rust demangling is the BFD-demangled
 257                    * name which it Rust-demangles in place.
 258                    */
 259                rust_demangle_sym(demangled);
 260
 261        return demangled;
 262}
 263
 264#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 265        for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 266             idx < nr_entries; \
 267             ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 268
 269#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 270        for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 271             idx < nr_entries; \
 272             ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 273
 274/*
 275 * We need to check if we have a .dynsym, so that we can handle the
 276 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 277 * .dynsym or .symtab).
 278 * And always look at the original dso, not at debuginfo packages, that
 279 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 280 */
 281int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 282{
 283        uint32_t nr_rel_entries, idx;
 284        GElf_Sym sym;
 285        u64 plt_offset, plt_header_size, plt_entry_size;
 286        GElf_Shdr shdr_plt;
 287        struct symbol *f;
 288        GElf_Shdr shdr_rel_plt, shdr_dynsym;
 289        Elf_Data *reldata, *syms, *symstrs;
 290        Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 291        size_t dynsym_idx;
 292        GElf_Ehdr ehdr;
 293        char sympltname[1024];
 294        Elf *elf;
 295        int nr = 0, symidx, err = 0;
 296
 297        if (!ss->dynsym)
 298                return 0;
 299
 300        elf = ss->elf;
 301        ehdr = ss->ehdr;
 302
 303        scn_dynsym = ss->dynsym;
 304        shdr_dynsym = ss->dynshdr;
 305        dynsym_idx = ss->dynsym_idx;
 306
 307        if (scn_dynsym == NULL)
 308                goto out_elf_end;
 309
 310        scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 311                                          ".rela.plt", NULL);
 312        if (scn_plt_rel == NULL) {
 313                scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 314                                                  ".rel.plt", NULL);
 315                if (scn_plt_rel == NULL)
 316                        goto out_elf_end;
 317        }
 318
 319        err = -1;
 320
 321        if (shdr_rel_plt.sh_link != dynsym_idx)
 322                goto out_elf_end;
 323
 324        if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 325                goto out_elf_end;
 326
 327        /*
 328         * Fetch the relocation section to find the idxes to the GOT
 329         * and the symbols in the .dynsym they refer to.
 330         */
 331        reldata = elf_getdata(scn_plt_rel, NULL);
 332        if (reldata == NULL)
 333                goto out_elf_end;
 334
 335        syms = elf_getdata(scn_dynsym, NULL);
 336        if (syms == NULL)
 337                goto out_elf_end;
 338
 339        scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 340        if (scn_symstrs == NULL)
 341                goto out_elf_end;
 342
 343        symstrs = elf_getdata(scn_symstrs, NULL);
 344        if (symstrs == NULL)
 345                goto out_elf_end;
 346
 347        if (symstrs->d_size == 0)
 348                goto out_elf_end;
 349
 350        nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 351        plt_offset = shdr_plt.sh_offset;
 352        switch (ehdr.e_machine) {
 353                case EM_ARM:
 354                        plt_header_size = 20;
 355                        plt_entry_size = 12;
 356                        break;
 357
 358                case EM_AARCH64:
 359                        plt_header_size = 32;
 360                        plt_entry_size = 16;
 361                        break;
 362
 363                case EM_SPARC:
 364                        plt_header_size = 48;
 365                        plt_entry_size = 12;
 366                        break;
 367
 368                case EM_SPARCV9:
 369                        plt_header_size = 128;
 370                        plt_entry_size = 32;
 371                        break;
 372
 373                default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 374                        plt_header_size = shdr_plt.sh_entsize;
 375                        plt_entry_size = shdr_plt.sh_entsize;
 376                        break;
 377        }
 378        plt_offset += plt_header_size;
 379
 380        if (shdr_rel_plt.sh_type == SHT_RELA) {
 381                GElf_Rela pos_mem, *pos;
 382
 383                elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 384                                           nr_rel_entries) {
 385                        const char *elf_name = NULL;
 386                        char *demangled = NULL;
 387                        symidx = GELF_R_SYM(pos->r_info);
 388                        gelf_getsym(syms, symidx, &sym);
 389
 390                        elf_name = elf_sym__name(&sym, symstrs);
 391                        demangled = demangle_sym(dso, 0, elf_name);
 392                        if (demangled != NULL)
 393                                elf_name = demangled;
 394                        snprintf(sympltname, sizeof(sympltname),
 395                                 "%s@plt", elf_name);
 396                        free(demangled);
 397
 398                        f = symbol__new(plt_offset, plt_entry_size,
 399                                        STB_GLOBAL, STT_FUNC, sympltname);
 400                        if (!f)
 401                                goto out_elf_end;
 402
 403                        plt_offset += plt_entry_size;
 404                        symbols__insert(&dso->symbols, f);
 405                        ++nr;
 406                }
 407        } else if (shdr_rel_plt.sh_type == SHT_REL) {
 408                GElf_Rel pos_mem, *pos;
 409                elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 410                                          nr_rel_entries) {
 411                        const char *elf_name = NULL;
 412                        char *demangled = NULL;
 413                        symidx = GELF_R_SYM(pos->r_info);
 414                        gelf_getsym(syms, symidx, &sym);
 415
 416                        elf_name = elf_sym__name(&sym, symstrs);
 417                        demangled = demangle_sym(dso, 0, elf_name);
 418                        if (demangled != NULL)
 419                                elf_name = demangled;
 420                        snprintf(sympltname, sizeof(sympltname),
 421                                 "%s@plt", elf_name);
 422                        free(demangled);
 423
 424                        f = symbol__new(plt_offset, plt_entry_size,
 425                                        STB_GLOBAL, STT_FUNC, sympltname);
 426                        if (!f)
 427                                goto out_elf_end;
 428
 429                        plt_offset += plt_entry_size;
 430                        symbols__insert(&dso->symbols, f);
 431                        ++nr;
 432                }
 433        }
 434
 435        err = 0;
 436out_elf_end:
 437        if (err == 0)
 438                return nr;
 439        pr_debug("%s: problems reading %s PLT info.\n",
 440                 __func__, dso->long_name);
 441        return 0;
 442}
 443
 444char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 445{
 446        return demangle_sym(dso, kmodule, elf_name);
 447}
 448
 449/*
 450 * Align offset to 4 bytes as needed for note name and descriptor data.
 451 */
 452#define NOTE_ALIGN(n) (((n) + 3) & -4U)
 453
 454static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 455{
 456        int err = -1;
 457        GElf_Ehdr ehdr;
 458        GElf_Shdr shdr;
 459        Elf_Data *data;
 460        Elf_Scn *sec;
 461        Elf_Kind ek;
 462        void *ptr;
 463
 464        if (size < BUILD_ID_SIZE)
 465                goto out;
 466
 467        ek = elf_kind(elf);
 468        if (ek != ELF_K_ELF)
 469                goto out;
 470
 471        if (gelf_getehdr(elf, &ehdr) == NULL) {
 472                pr_err("%s: cannot get elf header.\n", __func__);
 473                goto out;
 474        }
 475
 476        /*
 477         * Check following sections for notes:
 478         *   '.note.gnu.build-id'
 479         *   '.notes'
 480         *   '.note' (VDSO specific)
 481         */
 482        do {
 483                sec = elf_section_by_name(elf, &ehdr, &shdr,
 484                                          ".note.gnu.build-id", NULL);
 485                if (sec)
 486                        break;
 487
 488                sec = elf_section_by_name(elf, &ehdr, &shdr,
 489                                          ".notes", NULL);
 490                if (sec)
 491                        break;
 492
 493                sec = elf_section_by_name(elf, &ehdr, &shdr,
 494                                          ".note", NULL);
 495                if (sec)
 496                        break;
 497
 498                return err;
 499
 500        } while (0);
 501
 502        data = elf_getdata(sec, NULL);
 503        if (data == NULL)
 504                goto out;
 505
 506        ptr = data->d_buf;
 507        while (ptr < (data->d_buf + data->d_size)) {
 508                GElf_Nhdr *nhdr = ptr;
 509                size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 510                       descsz = NOTE_ALIGN(nhdr->n_descsz);
 511                const char *name;
 512
 513                ptr += sizeof(*nhdr);
 514                name = ptr;
 515                ptr += namesz;
 516                if (nhdr->n_type == NT_GNU_BUILD_ID &&
 517                    nhdr->n_namesz == sizeof("GNU")) {
 518                        if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 519                                size_t sz = min(size, descsz);
 520                                memcpy(bf, ptr, sz);
 521                                memset(bf + sz, 0, size - sz);
 522                                err = descsz;
 523                                break;
 524                        }
 525                }
 526                ptr += descsz;
 527        }
 528
 529out:
 530        return err;
 531}
 532
 533int filename__read_build_id(const char *filename, void *bf, size_t size)
 534{
 535        int fd, err = -1;
 536        Elf *elf;
 537
 538        if (size < BUILD_ID_SIZE)
 539                goto out;
 540
 541        fd = open(filename, O_RDONLY);
 542        if (fd < 0)
 543                goto out;
 544
 545        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 546        if (elf == NULL) {
 547                pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 548                goto out_close;
 549        }
 550
 551        err = elf_read_build_id(elf, bf, size);
 552
 553        elf_end(elf);
 554out_close:
 555        close(fd);
 556out:
 557        return err;
 558}
 559
 560int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 561{
 562        int fd, err = -1;
 563
 564        if (size < BUILD_ID_SIZE)
 565                goto out;
 566
 567        fd = open(filename, O_RDONLY);
 568        if (fd < 0)
 569                goto out;
 570
 571        while (1) {
 572                char bf[BUFSIZ];
 573                GElf_Nhdr nhdr;
 574                size_t namesz, descsz;
 575
 576                if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 577                        break;
 578
 579                namesz = NOTE_ALIGN(nhdr.n_namesz);
 580                descsz = NOTE_ALIGN(nhdr.n_descsz);
 581                if (nhdr.n_type == NT_GNU_BUILD_ID &&
 582                    nhdr.n_namesz == sizeof("GNU")) {
 583                        if (read(fd, bf, namesz) != (ssize_t)namesz)
 584                                break;
 585                        if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 586                                size_t sz = min(descsz, size);
 587                                if (read(fd, build_id, sz) == (ssize_t)sz) {
 588                                        memset(build_id + sz, 0, size - sz);
 589                                        err = 0;
 590                                        break;
 591                                }
 592                        } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 593                                break;
 594                } else {
 595                        int n = namesz + descsz;
 596
 597                        if (n > (int)sizeof(bf)) {
 598                                n = sizeof(bf);
 599                                pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 600                                         __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 601                        }
 602                        if (read(fd, bf, n) != n)
 603                                break;
 604                }
 605        }
 606        close(fd);
 607out:
 608        return err;
 609}
 610
 611int filename__read_debuglink(const char *filename, char *debuglink,
 612                             size_t size)
 613{
 614        int fd, err = -1;
 615        Elf *elf;
 616        GElf_Ehdr ehdr;
 617        GElf_Shdr shdr;
 618        Elf_Data *data;
 619        Elf_Scn *sec;
 620        Elf_Kind ek;
 621
 622        fd = open(filename, O_RDONLY);
 623        if (fd < 0)
 624                goto out;
 625
 626        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 627        if (elf == NULL) {
 628                pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 629                goto out_close;
 630        }
 631
 632        ek = elf_kind(elf);
 633        if (ek != ELF_K_ELF)
 634                goto out_elf_end;
 635
 636        if (gelf_getehdr(elf, &ehdr) == NULL) {
 637                pr_err("%s: cannot get elf header.\n", __func__);
 638                goto out_elf_end;
 639        }
 640
 641        sec = elf_section_by_name(elf, &ehdr, &shdr,
 642                                  ".gnu_debuglink", NULL);
 643        if (sec == NULL)
 644                goto out_elf_end;
 645
 646        data = elf_getdata(sec, NULL);
 647        if (data == NULL)
 648                goto out_elf_end;
 649
 650        /* the start of this section is a zero-terminated string */
 651        strncpy(debuglink, data->d_buf, size);
 652
 653        err = 0;
 654
 655out_elf_end:
 656        elf_end(elf);
 657out_close:
 658        close(fd);
 659out:
 660        return err;
 661}
 662
 663static int dso__swap_init(struct dso *dso, unsigned char eidata)
 664{
 665        static unsigned int const endian = 1;
 666
 667        dso->needs_swap = DSO_SWAP__NO;
 668
 669        switch (eidata) {
 670        case ELFDATA2LSB:
 671                /* We are big endian, DSO is little endian. */
 672                if (*(unsigned char const *)&endian != 1)
 673                        dso->needs_swap = DSO_SWAP__YES;
 674                break;
 675
 676        case ELFDATA2MSB:
 677                /* We are little endian, DSO is big endian. */
 678                if (*(unsigned char const *)&endian != 0)
 679                        dso->needs_swap = DSO_SWAP__YES;
 680                break;
 681
 682        default:
 683                pr_err("unrecognized DSO data encoding %d\n", eidata);
 684                return -EINVAL;
 685        }
 686
 687        return 0;
 688}
 689
 690bool symsrc__possibly_runtime(struct symsrc *ss)
 691{
 692        return ss->dynsym || ss->opdsec;
 693}
 694
 695bool symsrc__has_symtab(struct symsrc *ss)
 696{
 697        return ss->symtab != NULL;
 698}
 699
 700void symsrc__destroy(struct symsrc *ss)
 701{
 702        zfree(&ss->name);
 703        elf_end(ss->elf);
 704        close(ss->fd);
 705}
 706
 707bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 708{
 709        return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 710}
 711
 712int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 713                 enum dso_binary_type type)
 714{
 715        GElf_Ehdr ehdr;
 716        Elf *elf;
 717        int fd;
 718
 719        if (dso__needs_decompress(dso)) {
 720                fd = dso__decompress_kmodule_fd(dso, name);
 721                if (fd < 0)
 722                        return -1;
 723
 724                type = dso->symtab_type;
 725        } else {
 726                fd = open(name, O_RDONLY);
 727                if (fd < 0) {
 728                        dso->load_errno = errno;
 729                        return -1;
 730                }
 731        }
 732
 733        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 734        if (elf == NULL) {
 735                pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 736                dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 737                goto out_close;
 738        }
 739
 740        if (gelf_getehdr(elf, &ehdr) == NULL) {
 741                dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 742                pr_debug("%s: cannot get elf header.\n", __func__);
 743                goto out_elf_end;
 744        }
 745
 746        if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 747                dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 748                goto out_elf_end;
 749        }
 750
 751        /* Always reject images with a mismatched build-id: */
 752        if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 753                u8 build_id[BUILD_ID_SIZE];
 754
 755                if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 756                        dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 757                        goto out_elf_end;
 758                }
 759
 760                if (!dso__build_id_equal(dso, build_id)) {
 761                        pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 762                        dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 763                        goto out_elf_end;
 764                }
 765        }
 766
 767        ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 768
 769        ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 770                        NULL);
 771        if (ss->symshdr.sh_type != SHT_SYMTAB)
 772                ss->symtab = NULL;
 773
 774        ss->dynsym_idx = 0;
 775        ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 776                        &ss->dynsym_idx);
 777        if (ss->dynshdr.sh_type != SHT_DYNSYM)
 778                ss->dynsym = NULL;
 779
 780        ss->opdidx = 0;
 781        ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 782                        &ss->opdidx);
 783        if (ss->opdshdr.sh_type != SHT_PROGBITS)
 784                ss->opdsec = NULL;
 785
 786        if (dso->kernel == DSO_TYPE_USER)
 787                ss->adjust_symbols = true;
 788        else
 789                ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 790
 791        ss->name   = strdup(name);
 792        if (!ss->name) {
 793                dso->load_errno = errno;
 794                goto out_elf_end;
 795        }
 796
 797        ss->elf    = elf;
 798        ss->fd     = fd;
 799        ss->ehdr   = ehdr;
 800        ss->type   = type;
 801
 802        return 0;
 803
 804out_elf_end:
 805        elf_end(elf);
 806out_close:
 807        close(fd);
 808        return -1;
 809}
 810
 811/**
 812 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 813 * @kmap: kernel maps and relocation reference symbol
 814 *
 815 * This function returns %true if we are dealing with the kernel maps and the
 816 * relocation reference symbol has not yet been found.  Otherwise %false is
 817 * returned.
 818 */
 819static bool ref_reloc_sym_not_found(struct kmap *kmap)
 820{
 821        return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 822               !kmap->ref_reloc_sym->unrelocated_addr;
 823}
 824
 825/**
 826 * ref_reloc - kernel relocation offset.
 827 * @kmap: kernel maps and relocation reference symbol
 828 *
 829 * This function returns the offset of kernel addresses as determined by using
 830 * the relocation reference symbol i.e. if the kernel has not been relocated
 831 * then the return value is zero.
 832 */
 833static u64 ref_reloc(struct kmap *kmap)
 834{
 835        if (kmap && kmap->ref_reloc_sym &&
 836            kmap->ref_reloc_sym->unrelocated_addr)
 837                return kmap->ref_reloc_sym->addr -
 838                       kmap->ref_reloc_sym->unrelocated_addr;
 839        return 0;
 840}
 841
 842void __weak arch__sym_update(struct symbol *s __maybe_unused,
 843                GElf_Sym *sym __maybe_unused) { }
 844
 845static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 846                                      GElf_Sym *sym, GElf_Shdr *shdr,
 847                                      struct map_groups *kmaps, struct kmap *kmap,
 848                                      struct dso **curr_dsop, struct map **curr_mapp,
 849                                      const char *section_name,
 850                                      bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 851{
 852        struct dso *curr_dso = *curr_dsop;
 853        struct map *curr_map;
 854        char dso_name[PATH_MAX];
 855
 856        /* Adjust symbol to map to file offset */
 857        if (adjust_kernel_syms)
 858                sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 859
 860        if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 861                return 0;
 862
 863        if (strcmp(section_name, ".text") == 0) {
 864                /*
 865                 * The initial kernel mapping is based on
 866                 * kallsyms and identity maps.  Overwrite it to
 867                 * map to the kernel dso.
 868                 */
 869                if (*remap_kernel && dso->kernel) {
 870                        *remap_kernel = false;
 871                        map->start = shdr->sh_addr + ref_reloc(kmap);
 872                        map->end = map->start + shdr->sh_size;
 873                        map->pgoff = shdr->sh_offset;
 874                        map->map_ip = map__map_ip;
 875                        map->unmap_ip = map__unmap_ip;
 876                        /* Ensure maps are correctly ordered */
 877                        if (kmaps) {
 878                                map__get(map);
 879                                map_groups__remove(kmaps, map);
 880                                map_groups__insert(kmaps, map);
 881                                map__put(map);
 882                        }
 883                }
 884
 885                /*
 886                 * The initial module mapping is based on
 887                 * /proc/modules mapped to offset zero.
 888                 * Overwrite it to map to the module dso.
 889                 */
 890                if (*remap_kernel && kmodule) {
 891                        *remap_kernel = false;
 892                        map->pgoff = shdr->sh_offset;
 893                }
 894
 895                *curr_mapp = map;
 896                *curr_dsop = dso;
 897                return 0;
 898        }
 899
 900        if (!kmap)
 901                return 0;
 902
 903        snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
 904
 905        curr_map = map_groups__find_by_name(kmaps, dso_name);
 906        if (curr_map == NULL) {
 907                u64 start = sym->st_value;
 908
 909                if (kmodule)
 910                        start += map->start + shdr->sh_offset;
 911
 912                curr_dso = dso__new(dso_name);
 913                if (curr_dso == NULL)
 914                        return -1;
 915                curr_dso->kernel = dso->kernel;
 916                curr_dso->long_name = dso->long_name;
 917                curr_dso->long_name_len = dso->long_name_len;
 918                curr_map = map__new2(start, curr_dso);
 919                dso__put(curr_dso);
 920                if (curr_map == NULL)
 921                        return -1;
 922
 923                if (adjust_kernel_syms) {
 924                        curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
 925                        curr_map->end    = curr_map->start + shdr->sh_size;
 926                        curr_map->pgoff  = shdr->sh_offset;
 927                } else {
 928                        curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 929                }
 930                curr_dso->symtab_type = dso->symtab_type;
 931                map_groups__insert(kmaps, curr_map);
 932                /*
 933                 * Add it before we drop the referece to curr_map, i.e. while
 934                 * we still are sure to have a reference to this DSO via
 935                 * *curr_map->dso.
 936                 */
 937                dsos__add(&map->groups->machine->dsos, curr_dso);
 938                /* kmaps already got it */
 939                map__put(curr_map);
 940                dso__set_loaded(curr_dso);
 941                *curr_mapp = curr_map;
 942                *curr_dsop = curr_dso;
 943        } else
 944                *curr_dsop = curr_map->dso;
 945
 946        return 0;
 947}
 948
 949int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 950                  struct symsrc *runtime_ss, int kmodule)
 951{
 952        struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 953        struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 954        struct map *curr_map = map;
 955        struct dso *curr_dso = dso;
 956        Elf_Data *symstrs, *secstrs;
 957        uint32_t nr_syms;
 958        int err = -1;
 959        uint32_t idx;
 960        GElf_Ehdr ehdr;
 961        GElf_Shdr shdr;
 962        GElf_Shdr tshdr;
 963        Elf_Data *syms, *opddata = NULL;
 964        GElf_Sym sym;
 965        Elf_Scn *sec, *sec_strndx;
 966        Elf *elf;
 967        int nr = 0;
 968        bool remap_kernel = false, adjust_kernel_syms = false;
 969
 970        if (kmap && !kmaps)
 971                return -1;
 972
 973        dso->symtab_type = syms_ss->type;
 974        dso->is_64_bit = syms_ss->is_64_bit;
 975        dso->rel = syms_ss->ehdr.e_type == ET_REL;
 976
 977        /*
 978         * Modules may already have symbols from kallsyms, but those symbols
 979         * have the wrong values for the dso maps, so remove them.
 980         */
 981        if (kmodule && syms_ss->symtab)
 982                symbols__delete(&dso->symbols);
 983
 984        if (!syms_ss->symtab) {
 985                /*
 986                 * If the vmlinux is stripped, fail so we will fall back
 987                 * to using kallsyms. The vmlinux runtime symbols aren't
 988                 * of much use.
 989                 */
 990                if (dso->kernel)
 991                        goto out_elf_end;
 992
 993                syms_ss->symtab  = syms_ss->dynsym;
 994                syms_ss->symshdr = syms_ss->dynshdr;
 995        }
 996
 997        elf = syms_ss->elf;
 998        ehdr = syms_ss->ehdr;
 999        sec = syms_ss->symtab;
1000        shdr = syms_ss->symshdr;
1001
1002        if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1003                                ".text", NULL))
1004                dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1005
1006        if (runtime_ss->opdsec)
1007                opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1008
1009        syms = elf_getdata(sec, NULL);
1010        if (syms == NULL)
1011                goto out_elf_end;
1012
1013        sec = elf_getscn(elf, shdr.sh_link);
1014        if (sec == NULL)
1015                goto out_elf_end;
1016
1017        symstrs = elf_getdata(sec, NULL);
1018        if (symstrs == NULL)
1019                goto out_elf_end;
1020
1021        sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1022        if (sec_strndx == NULL)
1023                goto out_elf_end;
1024
1025        secstrs = elf_getdata(sec_strndx, NULL);
1026        if (secstrs == NULL)
1027                goto out_elf_end;
1028
1029        nr_syms = shdr.sh_size / shdr.sh_entsize;
1030
1031        memset(&sym, 0, sizeof(sym));
1032
1033        /*
1034         * The kernel relocation symbol is needed in advance in order to adjust
1035         * kernel maps correctly.
1036         */
1037        if (ref_reloc_sym_not_found(kmap)) {
1038                elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1039                        const char *elf_name = elf_sym__name(&sym, symstrs);
1040
1041                        if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1042                                continue;
1043                        kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1044                        map->reloc = kmap->ref_reloc_sym->addr -
1045                                     kmap->ref_reloc_sym->unrelocated_addr;
1046                        break;
1047                }
1048        }
1049
1050        /*
1051         * Handle any relocation of vdso necessary because older kernels
1052         * attempted to prelink vdso to its virtual address.
1053         */
1054        if (dso__is_vdso(dso))
1055                map->reloc = map->start - dso->text_offset;
1056
1057        dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1058        /*
1059         * Initial kernel and module mappings do not map to the dso.
1060         * Flag the fixups.
1061         */
1062        if (dso->kernel || kmodule) {
1063                remap_kernel = true;
1064                adjust_kernel_syms = dso->adjust_symbols;
1065        }
1066        elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1067                struct symbol *f;
1068                const char *elf_name = elf_sym__name(&sym, symstrs);
1069                char *demangled = NULL;
1070                int is_label = elf_sym__is_label(&sym);
1071                const char *section_name;
1072                bool used_opd = false;
1073
1074                if (!is_label && !elf_sym__filter(&sym))
1075                        continue;
1076
1077                /* Reject ARM ELF "mapping symbols": these aren't unique and
1078                 * don't identify functions, so will confuse the profile
1079                 * output: */
1080                if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1081                        if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1082                            && (elf_name[2] == '\0' || elf_name[2] == '.'))
1083                                continue;
1084                }
1085
1086                if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1087                        u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1088                        u64 *opd = opddata->d_buf + offset;
1089                        sym.st_value = DSO__SWAP(dso, u64, *opd);
1090                        sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1091                                        sym.st_value);
1092                        used_opd = true;
1093                }
1094                /*
1095                 * When loading symbols in a data mapping, ABS symbols (which
1096                 * has a value of SHN_ABS in its st_shndx) failed at
1097                 * elf_getscn().  And it marks the loading as a failure so
1098                 * already loaded symbols cannot be fixed up.
1099                 *
1100                 * I'm not sure what should be done. Just ignore them for now.
1101                 * - Namhyung Kim
1102                 */
1103                if (sym.st_shndx == SHN_ABS)
1104                        continue;
1105
1106                sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1107                if (!sec)
1108                        goto out_elf_end;
1109
1110                gelf_getshdr(sec, &shdr);
1111
1112                if (is_label && !elf_sec__filter(&shdr, secstrs))
1113                        continue;
1114
1115                section_name = elf_sec__name(&shdr, secstrs);
1116
1117                /* On ARM, symbols for thumb functions have 1 added to
1118                 * the symbol address as a flag - remove it */
1119                if ((ehdr.e_machine == EM_ARM) &&
1120                    (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1121                    (sym.st_value & 1))
1122                        --sym.st_value;
1123
1124                if (dso->kernel || kmodule) {
1125                        if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1126                                                       section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1127                                goto out_elf_end;
1128                } else if ((used_opd && runtime_ss->adjust_symbols) ||
1129                           (!used_opd && syms_ss->adjust_symbols)) {
1130                        pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1131                                  "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1132                                  (u64)sym.st_value, (u64)shdr.sh_addr,
1133                                  (u64)shdr.sh_offset);
1134                        sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1135                }
1136
1137                demangled = demangle_sym(dso, kmodule, elf_name);
1138                if (demangled != NULL)
1139                        elf_name = demangled;
1140
1141                f = symbol__new(sym.st_value, sym.st_size,
1142                                GELF_ST_BIND(sym.st_info),
1143                                GELF_ST_TYPE(sym.st_info), elf_name);
1144                free(demangled);
1145                if (!f)
1146                        goto out_elf_end;
1147
1148                arch__sym_update(f, &sym);
1149
1150                __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1151                nr++;
1152        }
1153
1154        /*
1155         * For misannotated, zeroed, ASM function sizes.
1156         */
1157        if (nr > 0) {
1158                symbols__fixup_end(&dso->symbols);
1159                symbols__fixup_duplicate(&dso->symbols);
1160                if (kmap) {
1161                        /*
1162                         * We need to fixup this here too because we create new
1163                         * maps here, for things like vsyscall sections.
1164                         */
1165                        map_groups__fixup_end(kmaps);
1166                }
1167        }
1168        err = nr;
1169out_elf_end:
1170        return err;
1171}
1172
1173static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1174{
1175        GElf_Phdr phdr;
1176        size_t i, phdrnum;
1177        int err;
1178        u64 sz;
1179
1180        if (elf_getphdrnum(elf, &phdrnum))
1181                return -1;
1182
1183        for (i = 0; i < phdrnum; i++) {
1184                if (gelf_getphdr(elf, i, &phdr) == NULL)
1185                        return -1;
1186                if (phdr.p_type != PT_LOAD)
1187                        continue;
1188                if (exe) {
1189                        if (!(phdr.p_flags & PF_X))
1190                                continue;
1191                } else {
1192                        if (!(phdr.p_flags & PF_R))
1193                                continue;
1194                }
1195                sz = min(phdr.p_memsz, phdr.p_filesz);
1196                if (!sz)
1197                        continue;
1198                err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1199                if (err)
1200                        return err;
1201        }
1202        return 0;
1203}
1204
1205int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1206                    bool *is_64_bit)
1207{
1208        int err;
1209        Elf *elf;
1210
1211        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1212        if (elf == NULL)
1213                return -1;
1214
1215        if (is_64_bit)
1216                *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1217
1218        err = elf_read_maps(elf, exe, mapfn, data);
1219
1220        elf_end(elf);
1221        return err;
1222}
1223
1224enum dso_type dso__type_fd(int fd)
1225{
1226        enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1227        GElf_Ehdr ehdr;
1228        Elf_Kind ek;
1229        Elf *elf;
1230
1231        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1232        if (elf == NULL)
1233                goto out;
1234
1235        ek = elf_kind(elf);
1236        if (ek != ELF_K_ELF)
1237                goto out_end;
1238
1239        if (gelf_getclass(elf) == ELFCLASS64) {
1240                dso_type = DSO__TYPE_64BIT;
1241                goto out_end;
1242        }
1243
1244        if (gelf_getehdr(elf, &ehdr) == NULL)
1245                goto out_end;
1246
1247        if (ehdr.e_machine == EM_X86_64)
1248                dso_type = DSO__TYPE_X32BIT;
1249        else
1250                dso_type = DSO__TYPE_32BIT;
1251out_end:
1252        elf_end(elf);
1253out:
1254        return dso_type;
1255}
1256
1257static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1258{
1259        ssize_t r;
1260        size_t n;
1261        int err = -1;
1262        char *buf = malloc(page_size);
1263
1264        if (buf == NULL)
1265                return -1;
1266
1267        if (lseek(to, to_offs, SEEK_SET) != to_offs)
1268                goto out;
1269
1270        if (lseek(from, from_offs, SEEK_SET) != from_offs)
1271                goto out;
1272
1273        while (len) {
1274                n = page_size;
1275                if (len < n)
1276                        n = len;
1277                /* Use read because mmap won't work on proc files */
1278                r = read(from, buf, n);
1279                if (r < 0)
1280                        goto out;
1281                if (!r)
1282                        break;
1283                n = r;
1284                r = write(to, buf, n);
1285                if (r < 0)
1286                        goto out;
1287                if ((size_t)r != n)
1288                        goto out;
1289                len -= n;
1290        }
1291
1292        err = 0;
1293out:
1294        free(buf);
1295        return err;
1296}
1297
1298struct kcore {
1299        int fd;
1300        int elfclass;
1301        Elf *elf;
1302        GElf_Ehdr ehdr;
1303};
1304
1305static int kcore__open(struct kcore *kcore, const char *filename)
1306{
1307        GElf_Ehdr *ehdr;
1308
1309        kcore->fd = open(filename, O_RDONLY);
1310        if (kcore->fd == -1)
1311                return -1;
1312
1313        kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1314        if (!kcore->elf)
1315                goto out_close;
1316
1317        kcore->elfclass = gelf_getclass(kcore->elf);
1318        if (kcore->elfclass == ELFCLASSNONE)
1319                goto out_end;
1320
1321        ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1322        if (!ehdr)
1323                goto out_end;
1324
1325        return 0;
1326
1327out_end:
1328        elf_end(kcore->elf);
1329out_close:
1330        close(kcore->fd);
1331        return -1;
1332}
1333
1334static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1335                       bool temp)
1336{
1337        kcore->elfclass = elfclass;
1338
1339        if (temp)
1340                kcore->fd = mkstemp(filename);
1341        else
1342                kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1343        if (kcore->fd == -1)
1344                return -1;
1345
1346        kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1347        if (!kcore->elf)
1348                goto out_close;
1349
1350        if (!gelf_newehdr(kcore->elf, elfclass))
1351                goto out_end;
1352
1353        memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1354
1355        return 0;
1356
1357out_end:
1358        elf_end(kcore->elf);
1359out_close:
1360        close(kcore->fd);
1361        unlink(filename);
1362        return -1;
1363}
1364
1365static void kcore__close(struct kcore *kcore)
1366{
1367        elf_end(kcore->elf);
1368        close(kcore->fd);
1369}
1370
1371static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1372{
1373        GElf_Ehdr *ehdr = &to->ehdr;
1374        GElf_Ehdr *kehdr = &from->ehdr;
1375
1376        memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1377        ehdr->e_type      = kehdr->e_type;
1378        ehdr->e_machine   = kehdr->e_machine;
1379        ehdr->e_version   = kehdr->e_version;
1380        ehdr->e_entry     = 0;
1381        ehdr->e_shoff     = 0;
1382        ehdr->e_flags     = kehdr->e_flags;
1383        ehdr->e_phnum     = count;
1384        ehdr->e_shentsize = 0;
1385        ehdr->e_shnum     = 0;
1386        ehdr->e_shstrndx  = 0;
1387
1388        if (from->elfclass == ELFCLASS32) {
1389                ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1390                ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1391                ehdr->e_phentsize = sizeof(Elf32_Phdr);
1392        } else {
1393                ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1394                ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1395                ehdr->e_phentsize = sizeof(Elf64_Phdr);
1396        }
1397
1398        if (!gelf_update_ehdr(to->elf, ehdr))
1399                return -1;
1400
1401        if (!gelf_newphdr(to->elf, count))
1402                return -1;
1403
1404        return 0;
1405}
1406
1407static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1408                           u64 addr, u64 len)
1409{
1410        GElf_Phdr phdr = {
1411                .p_type         = PT_LOAD,
1412                .p_flags        = PF_R | PF_W | PF_X,
1413                .p_offset       = offset,
1414                .p_vaddr        = addr,
1415                .p_paddr        = 0,
1416                .p_filesz       = len,
1417                .p_memsz        = len,
1418                .p_align        = page_size,
1419        };
1420
1421        if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1422                return -1;
1423
1424        return 0;
1425}
1426
1427static off_t kcore__write(struct kcore *kcore)
1428{
1429        return elf_update(kcore->elf, ELF_C_WRITE);
1430}
1431
1432struct phdr_data {
1433        off_t offset;
1434        off_t rel;
1435        u64 addr;
1436        u64 len;
1437        struct list_head node;
1438        struct phdr_data *remaps;
1439};
1440
1441struct sym_data {
1442        u64 addr;
1443        struct list_head node;
1444};
1445
1446struct kcore_copy_info {
1447        u64 stext;
1448        u64 etext;
1449        u64 first_symbol;
1450        u64 last_symbol;
1451        u64 first_module;
1452        u64 last_module_symbol;
1453        size_t phnum;
1454        struct list_head phdrs;
1455        struct list_head syms;
1456};
1457
1458#define kcore_copy__for_each_phdr(k, p) \
1459        list_for_each_entry((p), &(k)->phdrs, node)
1460
1461static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1462{
1463        struct phdr_data *p = zalloc(sizeof(*p));
1464
1465        if (p) {
1466                p->addr   = addr;
1467                p->len    = len;
1468                p->offset = offset;
1469        }
1470
1471        return p;
1472}
1473
1474static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1475                                                 u64 addr, u64 len,
1476                                                 off_t offset)
1477{
1478        struct phdr_data *p = phdr_data__new(addr, len, offset);
1479
1480        if (p)
1481                list_add_tail(&p->node, &kci->phdrs);
1482
1483        return p;
1484}
1485
1486static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1487{
1488        struct phdr_data *p, *tmp;
1489
1490        list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1491                list_del_init(&p->node);
1492                free(p);
1493        }
1494}
1495
1496static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1497                                            u64 addr)
1498{
1499        struct sym_data *s = zalloc(sizeof(*s));
1500
1501        if (s) {
1502                s->addr = addr;
1503                list_add_tail(&s->node, &kci->syms);
1504        }
1505
1506        return s;
1507}
1508
1509static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1510{
1511        struct sym_data *s, *tmp;
1512
1513        list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1514                list_del_init(&s->node);
1515                free(s);
1516        }
1517}
1518
1519static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1520                                        u64 start)
1521{
1522        struct kcore_copy_info *kci = arg;
1523
1524        if (!kallsyms__is_function(type))
1525                return 0;
1526
1527        if (strchr(name, '[')) {
1528                if (start > kci->last_module_symbol)
1529                        kci->last_module_symbol = start;
1530                return 0;
1531        }
1532
1533        if (!kci->first_symbol || start < kci->first_symbol)
1534                kci->first_symbol = start;
1535
1536        if (!kci->last_symbol || start > kci->last_symbol)
1537                kci->last_symbol = start;
1538
1539        if (!strcmp(name, "_stext")) {
1540                kci->stext = start;
1541                return 0;
1542        }
1543
1544        if (!strcmp(name, "_etext")) {
1545                kci->etext = start;
1546                return 0;
1547        }
1548
1549        if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1550                return -1;
1551
1552        return 0;
1553}
1554
1555static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1556                                      const char *dir)
1557{
1558        char kallsyms_filename[PATH_MAX];
1559
1560        scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1561
1562        if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1563                return -1;
1564
1565        if (kallsyms__parse(kallsyms_filename, kci,
1566                            kcore_copy__process_kallsyms) < 0)
1567                return -1;
1568
1569        return 0;
1570}
1571
1572static int kcore_copy__process_modules(void *arg,
1573                                       const char *name __maybe_unused,
1574                                       u64 start, u64 size __maybe_unused)
1575{
1576        struct kcore_copy_info *kci = arg;
1577
1578        if (!kci->first_module || start < kci->first_module)
1579                kci->first_module = start;
1580
1581        return 0;
1582}
1583
1584static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1585                                     const char *dir)
1586{
1587        char modules_filename[PATH_MAX];
1588
1589        scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1590
1591        if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1592                return -1;
1593
1594        if (modules__parse(modules_filename, kci,
1595                           kcore_copy__process_modules) < 0)
1596                return -1;
1597
1598        return 0;
1599}
1600
1601static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1602                           u64 pgoff, u64 s, u64 e)
1603{
1604        u64 len, offset;
1605
1606        if (s < start || s >= end)
1607                return 0;
1608
1609        offset = (s - start) + pgoff;
1610        len = e < end ? e - s : end - s;
1611
1612        return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1613}
1614
1615static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1616{
1617        struct kcore_copy_info *kci = data;
1618        u64 end = start + len;
1619        struct sym_data *sdat;
1620
1621        if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1622                return -1;
1623
1624        if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1625                            kci->last_module_symbol))
1626                return -1;
1627
1628        list_for_each_entry(sdat, &kci->syms, node) {
1629                u64 s = round_down(sdat->addr, page_size);
1630
1631                if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1632                        return -1;
1633        }
1634
1635        return 0;
1636}
1637
1638static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1639{
1640        if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1641                return -1;
1642
1643        return 0;
1644}
1645
1646static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1647{
1648        struct phdr_data *p, *k = NULL;
1649        u64 kend;
1650
1651        if (!kci->stext)
1652                return;
1653
1654        /* Find phdr that corresponds to the kernel map (contains stext) */
1655        kcore_copy__for_each_phdr(kci, p) {
1656                u64 pend = p->addr + p->len - 1;
1657
1658                if (p->addr <= kci->stext && pend >= kci->stext) {
1659                        k = p;
1660                        break;
1661                }
1662        }
1663
1664        if (!k)
1665                return;
1666
1667        kend = k->offset + k->len;
1668
1669        /* Find phdrs that remap the kernel */
1670        kcore_copy__for_each_phdr(kci, p) {
1671                u64 pend = p->offset + p->len;
1672
1673                if (p == k)
1674                        continue;
1675
1676                if (p->offset >= k->offset && pend <= kend)
1677                        p->remaps = k;
1678        }
1679}
1680
1681static void kcore_copy__layout(struct kcore_copy_info *kci)
1682{
1683        struct phdr_data *p;
1684        off_t rel = 0;
1685
1686        kcore_copy__find_remaps(kci);
1687
1688        kcore_copy__for_each_phdr(kci, p) {
1689                if (!p->remaps) {
1690                        p->rel = rel;
1691                        rel += p->len;
1692                }
1693                kci->phnum += 1;
1694        }
1695
1696        kcore_copy__for_each_phdr(kci, p) {
1697                struct phdr_data *k = p->remaps;
1698
1699                if (k)
1700                        p->rel = p->offset - k->offset + k->rel;
1701        }
1702}
1703
1704static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1705                                 Elf *elf)
1706{
1707        if (kcore_copy__parse_kallsyms(kci, dir))
1708                return -1;
1709
1710        if (kcore_copy__parse_modules(kci, dir))
1711                return -1;
1712
1713        if (kci->stext)
1714                kci->stext = round_down(kci->stext, page_size);
1715        else
1716                kci->stext = round_down(kci->first_symbol, page_size);
1717
1718        if (kci->etext) {
1719                kci->etext = round_up(kci->etext, page_size);
1720        } else if (kci->last_symbol) {
1721                kci->etext = round_up(kci->last_symbol, page_size);
1722                kci->etext += page_size;
1723        }
1724
1725        kci->first_module = round_down(kci->first_module, page_size);
1726
1727        if (kci->last_module_symbol) {
1728                kci->last_module_symbol = round_up(kci->last_module_symbol,
1729                                                   page_size);
1730                kci->last_module_symbol += page_size;
1731        }
1732
1733        if (!kci->stext || !kci->etext)
1734                return -1;
1735
1736        if (kci->first_module && !kci->last_module_symbol)
1737                return -1;
1738
1739        if (kcore_copy__read_maps(kci, elf))
1740                return -1;
1741
1742        kcore_copy__layout(kci);
1743
1744        return 0;
1745}
1746
1747static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1748                                 const char *name)
1749{
1750        char from_filename[PATH_MAX];
1751        char to_filename[PATH_MAX];
1752
1753        scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1754        scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1755
1756        return copyfile_mode(from_filename, to_filename, 0400);
1757}
1758
1759static int kcore_copy__unlink(const char *dir, const char *name)
1760{
1761        char filename[PATH_MAX];
1762
1763        scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1764
1765        return unlink(filename);
1766}
1767
1768static int kcore_copy__compare_fds(int from, int to)
1769{
1770        char *buf_from;
1771        char *buf_to;
1772        ssize_t ret;
1773        size_t len;
1774        int err = -1;
1775
1776        buf_from = malloc(page_size);
1777        buf_to = malloc(page_size);
1778        if (!buf_from || !buf_to)
1779                goto out;
1780
1781        while (1) {
1782                /* Use read because mmap won't work on proc files */
1783                ret = read(from, buf_from, page_size);
1784                if (ret < 0)
1785                        goto out;
1786
1787                if (!ret)
1788                        break;
1789
1790                len = ret;
1791
1792                if (readn(to, buf_to, len) != (int)len)
1793                        goto out;
1794
1795                if (memcmp(buf_from, buf_to, len))
1796                        goto out;
1797        }
1798
1799        err = 0;
1800out:
1801        free(buf_to);
1802        free(buf_from);
1803        return err;
1804}
1805
1806static int kcore_copy__compare_files(const char *from_filename,
1807                                     const char *to_filename)
1808{
1809        int from, to, err = -1;
1810
1811        from = open(from_filename, O_RDONLY);
1812        if (from < 0)
1813                return -1;
1814
1815        to = open(to_filename, O_RDONLY);
1816        if (to < 0)
1817                goto out_close_from;
1818
1819        err = kcore_copy__compare_fds(from, to);
1820
1821        close(to);
1822out_close_from:
1823        close(from);
1824        return err;
1825}
1826
1827static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1828                                    const char *name)
1829{
1830        char from_filename[PATH_MAX];
1831        char to_filename[PATH_MAX];
1832
1833        scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1834        scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1835
1836        return kcore_copy__compare_files(from_filename, to_filename);
1837}
1838
1839/**
1840 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1841 * @from_dir: from directory
1842 * @to_dir: to directory
1843 *
1844 * This function copies kallsyms, modules and kcore files from one directory to
1845 * another.  kallsyms and modules are copied entirely.  Only code segments are
1846 * copied from kcore.  It is assumed that two segments suffice: one for the
1847 * kernel proper and one for all the modules.  The code segments are determined
1848 * from kallsyms and modules files.  The kernel map starts at _stext or the
1849 * lowest function symbol, and ends at _etext or the highest function symbol.
1850 * The module map starts at the lowest module address and ends at the highest
1851 * module symbol.  Start addresses are rounded down to the nearest page.  End
1852 * addresses are rounded up to the nearest page.  An extra page is added to the
1853 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1854 * symbol too.  Because it contains only code sections, the resulting kcore is
1855 * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1856 * is not the same for the kernel map and the modules map.  That happens because
1857 * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1858 * kallsyms and modules files are compared with their copies to check that
1859 * modules have not been loaded or unloaded while the copies were taking place.
1860 *
1861 * Return: %0 on success, %-1 on failure.
1862 */
1863int kcore_copy(const char *from_dir, const char *to_dir)
1864{
1865        struct kcore kcore;
1866        struct kcore extract;
1867        int idx = 0, err = -1;
1868        off_t offset, sz;
1869        struct kcore_copy_info kci = { .stext = 0, };
1870        char kcore_filename[PATH_MAX];
1871        char extract_filename[PATH_MAX];
1872        struct phdr_data *p;
1873
1874        INIT_LIST_HEAD(&kci.phdrs);
1875        INIT_LIST_HEAD(&kci.syms);
1876
1877        if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1878                return -1;
1879
1880        if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1881                goto out_unlink_kallsyms;
1882
1883        scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1884        scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1885
1886        if (kcore__open(&kcore, kcore_filename))
1887                goto out_unlink_modules;
1888
1889        if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1890                goto out_kcore_close;
1891
1892        if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1893                goto out_kcore_close;
1894
1895        if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1896                goto out_extract_close;
1897
1898        offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1899                 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1900        offset = round_up(offset, page_size);
1901
1902        kcore_copy__for_each_phdr(&kci, p) {
1903                off_t offs = p->rel + offset;
1904
1905                if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1906                        goto out_extract_close;
1907        }
1908
1909        sz = kcore__write(&extract);
1910        if (sz < 0 || sz > offset)
1911                goto out_extract_close;
1912
1913        kcore_copy__for_each_phdr(&kci, p) {
1914                off_t offs = p->rel + offset;
1915
1916                if (p->remaps)
1917                        continue;
1918                if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1919                        goto out_extract_close;
1920        }
1921
1922        if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1923                goto out_extract_close;
1924
1925        if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1926                goto out_extract_close;
1927
1928        err = 0;
1929
1930out_extract_close:
1931        kcore__close(&extract);
1932        if (err)
1933                unlink(extract_filename);
1934out_kcore_close:
1935        kcore__close(&kcore);
1936out_unlink_modules:
1937        if (err)
1938                kcore_copy__unlink(to_dir, "modules");
1939out_unlink_kallsyms:
1940        if (err)
1941                kcore_copy__unlink(to_dir, "kallsyms");
1942
1943        kcore_copy__free_phdrs(&kci);
1944        kcore_copy__free_syms(&kci);
1945
1946        return err;
1947}
1948
1949int kcore_extract__create(struct kcore_extract *kce)
1950{
1951        struct kcore kcore;
1952        struct kcore extract;
1953        size_t count = 1;
1954        int idx = 0, err = -1;
1955        off_t offset = page_size, sz;
1956
1957        if (kcore__open(&kcore, kce->kcore_filename))
1958                return -1;
1959
1960        strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1961        if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1962                goto out_kcore_close;
1963
1964        if (kcore__copy_hdr(&kcore, &extract, count))
1965                goto out_extract_close;
1966
1967        if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1968                goto out_extract_close;
1969
1970        sz = kcore__write(&extract);
1971        if (sz < 0 || sz > offset)
1972                goto out_extract_close;
1973
1974        if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1975                goto out_extract_close;
1976
1977        err = 0;
1978
1979out_extract_close:
1980        kcore__close(&extract);
1981        if (err)
1982                unlink(kce->extract_filename);
1983out_kcore_close:
1984        kcore__close(&kcore);
1985
1986        return err;
1987}
1988
1989void kcore_extract__delete(struct kcore_extract *kce)
1990{
1991        unlink(kce->extract_filename);
1992}
1993
1994#ifdef HAVE_GELF_GETNOTE_SUPPORT
1995
1996static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
1997{
1998        if (!base_off)
1999                return;
2000
2001        if (tmp->bit32)
2002                tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2003                        tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2004                        tmp->addr.a32[SDT_NOTE_IDX_BASE];
2005        else
2006                tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2007                        tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2008                        tmp->addr.a64[SDT_NOTE_IDX_BASE];
2009}
2010
2011static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2012                              GElf_Addr base_off)
2013{
2014        if (!base_off)
2015                return;
2016
2017        if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2018                tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2019        else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2020                tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2021}
2022
2023/**
2024 * populate_sdt_note : Parse raw data and identify SDT note
2025 * @elf: elf of the opened file
2026 * @data: raw data of a section with description offset applied
2027 * @len: note description size
2028 * @type: type of the note
2029 * @sdt_notes: List to add the SDT note
2030 *
2031 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2032 * if its an SDT note, it appends to @sdt_notes list.
2033 */
2034static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2035                             struct list_head *sdt_notes)
2036{
2037        const char *provider, *name, *args;
2038        struct sdt_note *tmp = NULL;
2039        GElf_Ehdr ehdr;
2040        GElf_Shdr shdr;
2041        int ret = -EINVAL;
2042
2043        union {
2044                Elf64_Addr a64[NR_ADDR];
2045                Elf32_Addr a32[NR_ADDR];
2046        } buf;
2047
2048        Elf_Data dst = {
2049                .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2050                .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2051                .d_off = 0, .d_align = 0
2052        };
2053        Elf_Data src = {
2054                .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2055                .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2056                .d_align = 0
2057        };
2058
2059        tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2060        if (!tmp) {
2061                ret = -ENOMEM;
2062                goto out_err;
2063        }
2064
2065        INIT_LIST_HEAD(&tmp->note_list);
2066
2067        if (len < dst.d_size + 3)
2068                goto out_free_note;
2069
2070        /* Translation from file representation to memory representation */
2071        if (gelf_xlatetom(*elf, &dst, &src,
2072                          elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2073                pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2074                goto out_free_note;
2075        }
2076
2077        /* Populate the fields of sdt_note */
2078        provider = data + dst.d_size;
2079
2080        name = (const char *)memchr(provider, '\0', data + len - provider);
2081        if (name++ == NULL)
2082                goto out_free_note;
2083
2084        tmp->provider = strdup(provider);
2085        if (!tmp->provider) {
2086                ret = -ENOMEM;
2087                goto out_free_note;
2088        }
2089        tmp->name = strdup(name);
2090        if (!tmp->name) {
2091                ret = -ENOMEM;
2092                goto out_free_prov;
2093        }
2094
2095        args = memchr(name, '\0', data + len - name);
2096
2097        /*
2098         * There is no argument if:
2099         * - We reached the end of the note;
2100         * - There is not enough room to hold a potential string;
2101         * - The argument string is empty or just contains ':'.
2102         */
2103        if (args == NULL || data + len - args < 2 ||
2104                args[1] == ':' || args[1] == '\0')
2105                tmp->args = NULL;
2106        else {
2107                tmp->args = strdup(++args);
2108                if (!tmp->args) {
2109                        ret = -ENOMEM;
2110                        goto out_free_name;
2111                }
2112        }
2113
2114        if (gelf_getclass(*elf) == ELFCLASS32) {
2115                memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2116                tmp->bit32 = true;
2117        } else {
2118                memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2119                tmp->bit32 = false;
2120        }
2121
2122        if (!gelf_getehdr(*elf, &ehdr)) {
2123                pr_debug("%s : cannot get elf header.\n", __func__);
2124                ret = -EBADF;
2125                goto out_free_args;
2126        }
2127
2128        /* Adjust the prelink effect :
2129         * Find out the .stapsdt.base section.
2130         * This scn will help us to handle prelinking (if present).
2131         * Compare the retrieved file offset of the base section with the
2132         * base address in the description of the SDT note. If its different,
2133         * then accordingly, adjust the note location.
2134         */
2135        if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2136                sdt_adjust_loc(tmp, shdr.sh_offset);
2137
2138        /* Adjust reference counter offset */
2139        if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2140                sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2141
2142        list_add_tail(&tmp->note_list, sdt_notes);
2143        return 0;
2144
2145out_free_args:
2146        zfree(&tmp->args);
2147out_free_name:
2148        zfree(&tmp->name);
2149out_free_prov:
2150        zfree(&tmp->provider);
2151out_free_note:
2152        free(tmp);
2153out_err:
2154        return ret;
2155}
2156
2157/**
2158 * construct_sdt_notes_list : constructs a list of SDT notes
2159 * @elf : elf to look into
2160 * @sdt_notes : empty list_head
2161 *
2162 * Scans the sections in 'elf' for the section
2163 * .note.stapsdt. It, then calls populate_sdt_note to find
2164 * out the SDT events and populates the 'sdt_notes'.
2165 */
2166static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2167{
2168        GElf_Ehdr ehdr;
2169        Elf_Scn *scn = NULL;
2170        Elf_Data *data;
2171        GElf_Shdr shdr;
2172        size_t shstrndx, next;
2173        GElf_Nhdr nhdr;
2174        size_t name_off, desc_off, offset;
2175        int ret = 0;
2176
2177        if (gelf_getehdr(elf, &ehdr) == NULL) {
2178                ret = -EBADF;
2179                goto out_ret;
2180        }
2181        if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2182                ret = -EBADF;
2183                goto out_ret;
2184        }
2185
2186        /* Look for the required section */
2187        scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2188        if (!scn) {
2189                ret = -ENOENT;
2190                goto out_ret;
2191        }
2192
2193        if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2194                ret = -ENOENT;
2195                goto out_ret;
2196        }
2197
2198        data = elf_getdata(scn, NULL);
2199
2200        /* Get the SDT notes */
2201        for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2202                                              &desc_off)) > 0; offset = next) {
2203                if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2204                    !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2205                            sizeof(SDT_NOTE_NAME))) {
2206                        /* Check the type of the note */
2207                        if (nhdr.n_type != SDT_NOTE_TYPE)
2208                                goto out_ret;
2209
2210                        ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2211                                                nhdr.n_descsz, sdt_notes);
2212                        if (ret < 0)
2213                                goto out_ret;
2214                }
2215        }
2216        if (list_empty(sdt_notes))
2217                ret = -ENOENT;
2218
2219out_ret:
2220        return ret;
2221}
2222
2223/**
2224 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2225 * @head : empty list_head
2226 * @target : file to find SDT notes from
2227 *
2228 * This opens the file, initializes
2229 * the ELF and then calls construct_sdt_notes_list.
2230 */
2231int get_sdt_note_list(struct list_head *head, const char *target)
2232{
2233        Elf *elf;
2234        int fd, ret;
2235
2236        fd = open(target, O_RDONLY);
2237        if (fd < 0)
2238                return -EBADF;
2239
2240        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2241        if (!elf) {
2242                ret = -EBADF;
2243                goto out_close;
2244        }
2245        ret = construct_sdt_notes_list(elf, head);
2246        elf_end(elf);
2247out_close:
2248        close(fd);
2249        return ret;
2250}
2251
2252/**
2253 * cleanup_sdt_note_list : free the sdt notes' list
2254 * @sdt_notes: sdt notes' list
2255 *
2256 * Free up the SDT notes in @sdt_notes.
2257 * Returns the number of SDT notes free'd.
2258 */
2259int cleanup_sdt_note_list(struct list_head *sdt_notes)
2260{
2261        struct sdt_note *tmp, *pos;
2262        int nr_free = 0;
2263
2264        list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2265                list_del_init(&pos->note_list);
2266                zfree(&pos->name);
2267                zfree(&pos->provider);
2268                free(pos);
2269                nr_free++;
2270        }
2271        return nr_free;
2272}
2273
2274/**
2275 * sdt_notes__get_count: Counts the number of sdt events
2276 * @start: list_head to sdt_notes list
2277 *
2278 * Returns the number of SDT notes in a list
2279 */
2280int sdt_notes__get_count(struct list_head *start)
2281{
2282        struct sdt_note *sdt_ptr;
2283        int count = 0;
2284
2285        list_for_each_entry(sdt_ptr, start, note_list)
2286                count++;
2287        return count;
2288}
2289#endif
2290
2291void symbol__elf_init(void)
2292{
2293        elf_version(EV_CURRENT);
2294}
2295