tools/perf/util/symbol-elf.c

   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 "maps.h"
  13 #include "symbol.h"
  14 #include "symsrc.h"
  15 #include "demangle-cxx.h"
  16 #include "demangle-ocaml.h"
  17 #include "demangle-java.h"
  18 #include "demangle-rust.h"
  19 #include "machine.h"
  20 #include "vdso.h"
  21 #include "debug.h"
  22 #include "util/copyfile.h"
  23 #include <linux/ctype.h>
  24 #include <linux/kernel.h>
  25 #include <linux/zalloc.h>
  26 #include <symbol/kallsyms.h>
  27 #include <internal/lib.h>
  28
  29 #ifdef HAVE_LIBBFD_SUPPORT
  30 #define PACKAGE 'perf'
  31 #include <bfd.h>
  32 #endif
  33
  34 #ifndef EM_AARCH64
  35 #define EM_AARCH64      183  /* ARM 64 bit */
  36 #endif
  37
  38 #ifndef ELF32_ST_VISIBILITY
  39 #define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  40 #endif
  41
  42 /* For ELF64 the definitions are the same.  */
  43 #ifndef ELF64_ST_VISIBILITY
  44 #define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  45 #endif
  46
  47 /* How to extract information held in the st_other field.  */
  48 #ifndef GELF_ST_VISIBILITY
  49 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  50 #endif
  51
  52 typedef Elf64_Nhdr GElf_Nhdr;
  53
  54
  55 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  56 static int elf_getphdrnum(Elf *elf, size_t *dst)
  57 {
  58         GElf_Ehdr gehdr;
  59         GElf_Ehdr *ehdr;
  60
  61         ehdr = gelf_getehdr(elf, &gehdr);
  62         if (!ehdr)
  63                 return -1;
  64
  65         *dst = ehdr->e_phnum;
  66
  67         return 0;
  68 }
  69 #endif
  70
  71 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  72 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  73 {
  74         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  75         return -1;
  76 }
  77 #endif
  78
  79 #ifndef NT_GNU_BUILD_ID
  80 #define NT_GNU_BUILD_ID 3
  81 #endif
  82
  83 /**
  84  * elf_symtab__for_each_symbol - iterate thru all the symbols
  85  *
  86  * @syms: struct elf_symtab instance to iterate
  87  * @idx: uint32_t idx
  88  * @sym: GElf_Sym iterator
  89  */
  90 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  91         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  92              idx < nr_syms; \
  93              idx++, gelf_getsym(syms, idx, &sym))
  94
  95 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  96 {
  97         return GELF_ST_TYPE(sym->st_info);
  98 }
  99
 100 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 101 {
 102         return GELF_ST_VISIBILITY(sym->st_other);
 103 }
 104
 105 #ifndef STT_GNU_IFUNC
 106 #define STT_GNU_IFUNC 10
 107 #endif
 108
 109 static inline int elf_sym__is_function(const GElf_Sym *sym)
 110 {
 111         return (elf_sym__type(sym) == STT_FUNC ||
 112                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 113                sym->st_name != 0 &&
 114                sym->st_shndx != SHN_UNDEF;
 115 }
 116
 117 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 118 {
 119         return elf_sym__type(sym) == STT_OBJECT &&
 120                 sym->st_name != 0 &&
 121                 sym->st_shndx != SHN_UNDEF;
 122 }
 123
 124 static inline int elf_sym__is_label(const GElf_Sym *sym)
 125 {
 126         return elf_sym__type(sym) == STT_NOTYPE &&
 127                 sym->st_name != 0 &&
 128                 sym->st_shndx != SHN_UNDEF &&
 129                 sym->st_shndx != SHN_ABS &&
 130                 elf_sym__visibility(sym) != STV_HIDDEN &&
 131                 elf_sym__visibility(sym) != STV_INTERNAL;
 132 }
 133
 134 static bool elf_sym__filter(GElf_Sym *sym)
 135 {
 136         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 137 }
 138
 139 static inline const char *elf_sym__name(const GElf_Sym *sym,
 140                                         const Elf_Data *symstrs)
 141 {
 142         return symstrs->d_buf + sym->st_name;
 143 }
 144
 145 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 146                                         const Elf_Data *secstrs)
 147 {
 148         return secstrs->d_buf + shdr->sh_name;
 149 }
 150
 151 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 152                                         const Elf_Data *secstrs)
 153 {
 154         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 155 }
 156
 157 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 158                                     const Elf_Data *secstrs)
 159 {
 160         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 161 }
 162
 163 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 164 {
 165         return elf_sec__is_text(shdr, secstrs) ||
 166                elf_sec__is_data(shdr, secstrs);
 167 }
 168
 169 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 170 {
 171         Elf_Scn *sec = NULL;
 172         GElf_Shdr shdr;
 173         size_t cnt = 1;
 174
 175         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 176                 gelf_getshdr(sec, &shdr);
 177
 178                 if ((addr >= shdr.sh_addr) &&
 179                     (addr < (shdr.sh_addr + shdr.sh_size)))
 180                         return cnt;
 181
 182                 ++cnt;
 183         }
 184
 185         return -1;
 186 }
 187
 188 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 189                              GElf_Shdr *shp, const char *name, size_t *idx)
 190 {
 191         Elf_Scn *sec = NULL;
 192         size_t cnt = 1;
 193
 194         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 195         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 196                 return NULL;
 197
 198         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 199                 char *str;
 200
 201                 gelf_getshdr(sec, shp);
 202                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 203                 if (str && !strcmp(name, str)) {
 204                         if (idx)
 205                                 *idx = cnt;
 206                         return sec;
 207                 }
 208                 ++cnt;
 209         }
 210
 211         return NULL;
 212 }
 213
 214 bool filename__has_section(const char *filename, const char *sec)
 215 {
 216         int fd;
 217         Elf *elf;
 218         GElf_Ehdr ehdr;
 219         GElf_Shdr shdr;
 220         bool found = false;
 221
 222         fd = open(filename, O_RDONLY);
 223         if (fd < 0)
 224                 return false;
 225
 226         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 227         if (elf == NULL)
 228                 goto out;
 229
 230         if (gelf_getehdr(elf, &ehdr) == NULL)
 231                 goto elf_out;
 232
 233         found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL);
 234
 235 elf_out:
 236         elf_end(elf);
 237 out:
 238         close(fd);
 239         return found;
 240 }
 241
 242 static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr)
 243 {
 244         size_t i, phdrnum;
 245         u64 sz;
 246
 247         if (elf_getphdrnum(elf, &phdrnum))
 248                 return -1;
 249
 250         for (i = 0; i < phdrnum; i++) {
 251                 if (gelf_getphdr(elf, i, phdr) == NULL)
 252                         return -1;
 253
 254                 if (phdr->p_type != PT_LOAD)
 255                         continue;
 256
 257                 sz = max(phdr->p_memsz, phdr->p_filesz);
 258                 if (!sz)
 259                         continue;
 260
 261                 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz))
 262                         return 0;
 263         }
 264
 265         /* Not found any valid program header */
 266         return -1;
 267 }
 268
 269 static bool want_demangle(bool is_kernel_sym)
 270 {
 271         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 272 }
 273
 274 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 275 {
 276         char *demangled = NULL;
 277
 278         /*
 279          * We need to figure out if the object was created from C++ sources
 280          * DWARF DW_compile_unit has this, but we don't always have access
 281          * to it...
 282          */
 283         if (!want_demangle(dso->kernel || kmodule))
 284             return demangled;
 285
 286         demangled = cxx_demangle_sym(elf_name, verbose > 0, verbose > 0);
 287         if (demangled == NULL) {
 288                 demangled = ocaml_demangle_sym(elf_name);
 289                 if (demangled == NULL) {
 290                         demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 291                 }
 292         }
 293         else if (rust_is_mangled(demangled))
 294                 /*
 295                     * Input to Rust demangling is the BFD-demangled
 296                     * name which it Rust-demangles in place.
 297                     */
 298                 rust_demangle_sym(demangled);
 299
 300         return demangled;
 301 }
 302
 303 struct rel_info {
 304         u32             nr_entries;
 305         u32             *sorted;
 306         bool            is_rela;
 307         Elf_Data        *reldata;
 308         GElf_Rela       rela;
 309         GElf_Rel        rel;
 310 };
 311
 312 static u32 get_rel_symidx(struct rel_info *ri, u32 idx)
 313 {
 314         idx = ri->sorted ? ri->sorted[idx] : idx;
 315         if (ri->is_rela) {
 316                 gelf_getrela(ri->reldata, idx, &ri->rela);
 317                 return GELF_R_SYM(ri->rela.r_info);
 318         }
 319         gelf_getrel(ri->reldata, idx, &ri->rel);
 320         return GELF_R_SYM(ri->rel.r_info);
 321 }
 322
 323 static u64 get_rel_offset(struct rel_info *ri, u32 x)
 324 {
 325         if (ri->is_rela) {
 326                 GElf_Rela rela;
 327
 328                 gelf_getrela(ri->reldata, x, &rela);
 329                 return rela.r_offset;
 330         } else {
 331                 GElf_Rel rel;
 332
 333                 gelf_getrel(ri->reldata, x, &rel);
 334                 return rel.r_offset;
 335         }
 336 }
 337
 338 static int rel_cmp(const void *a, const void *b, void *r)
 339 {
 340         struct rel_info *ri = r;
 341         u64 a_offset = get_rel_offset(ri, *(const u32 *)a);
 342         u64 b_offset = get_rel_offset(ri, *(const u32 *)b);
 343
 344         return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0);
 345 }
 346
 347 static int sort_rel(struct rel_info *ri)
 348 {
 349         size_t sz = sizeof(ri->sorted[0]);
 350         u32 i;
 351
 352         ri->sorted = calloc(ri->nr_entries, sz);
 353         if (!ri->sorted)
 354                 return -1;
 355         for (i = 0; i < ri->nr_entries; i++)
 356                 ri->sorted[i] = i;
 357         qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri);
 358         return 0;
 359 }
 360
 361 /*
 362  * For x86_64, the GNU linker is putting IFUNC information in the relocation
 363  * addend.
 364  */
 365 static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri)
 366 {
 367         return ehdr->e_machine == EM_X86_64 && ri->is_rela &&
 368                GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE;
 369 }
 370
 371 static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr,
 372                            struct rel_info *ri, char *buf, size_t buf_sz)
 373 {
 374         u64 addr = ri->rela.r_addend;
 375         struct symbol *sym;
 376         GElf_Phdr phdr;
 377
 378         if (!addend_may_be_ifunc(ehdr, ri))
 379                 return false;
 380
 381         if (elf_read_program_header(elf, addr, &phdr))
 382                 return false;
 383
 384         addr -= phdr.p_vaddr - phdr.p_offset;
 385
 386         sym = dso__find_symbol_nocache(dso, addr);
 387
 388         /* Expecting the address to be an IFUNC or IFUNC alias */
 389         if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias))
 390                 return false;
 391
 392         snprintf(buf, buf_sz, "%s@plt", sym->name);
 393
 394         return true;
 395 }
 396
 397 static void exit_rel(struct rel_info *ri)
 398 {
 399         zfree(&ri->sorted);
 400 }
 401
 402 static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
 403                           u64 *plt_header_size, u64 *plt_entry_size)
 404 {
 405         switch (ehdr->e_machine) {
 406         case EM_ARM:
 407                 *plt_header_size = 20;
 408                 *plt_entry_size = 12;
 409                 return true;
 410         case EM_AARCH64:
 411                 *plt_header_size = 32;
 412                 *plt_entry_size = 16;
 413                 return true;
 414         case EM_SPARC:
 415                 *plt_header_size = 48;
 416                 *plt_entry_size = 12;
 417                 return true;
 418         case EM_SPARCV9:
 419                 *plt_header_size = 128;
 420                 *plt_entry_size = 32;
 421                 return true;
 422         case EM_386:
 423         case EM_X86_64:
 424                 *plt_entry_size = shdr_plt->sh_entsize;
 425                 /* Size is 8 or 16, if not, assume alignment indicates size */
 426                 if (*plt_entry_size != 8 && *plt_entry_size != 16)
 427                         *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16;
 428                 *plt_header_size = *plt_entry_size;
 429                 break;
 430         default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 431                 *plt_header_size = shdr_plt->sh_entsize;
 432                 *plt_entry_size = shdr_plt->sh_entsize;
 433                 break;
 434         }
 435         if (*plt_entry_size)
 436                 return true;
 437         pr_debug("Missing PLT entry size for %s\n", dso->long_name);
 438         return false;
 439 }
 440
 441 static bool machine_is_x86(GElf_Half e_machine)
 442 {
 443         return e_machine == EM_386 || e_machine == EM_X86_64;
 444 }
 445
 446 struct rela_dyn {
 447         GElf_Addr       offset;
 448         u32             sym_idx;
 449 };
 450
 451 struct rela_dyn_info {
 452         struct dso      *dso;
 453         Elf_Data        *plt_got_data;
 454         u32             nr_entries;
 455         struct rela_dyn *sorted;
 456         Elf_Data        *dynsym_data;
 457         Elf_Data        *dynstr_data;
 458         Elf_Data        *rela_dyn_data;
 459 };
 460
 461 static void exit_rela_dyn(struct rela_dyn_info *di)
 462 {
 463         zfree(&di->sorted);
 464 }
 465
 466 static int cmp_offset(const void *a, const void *b)
 467 {
 468         const struct rela_dyn *va = a;
 469         const struct rela_dyn *vb = b;
 470
 471         return va->offset < vb->offset ? -1 : (va->offset > vb->offset ? 1 : 0);
 472 }
 473
 474 static int sort_rela_dyn(struct rela_dyn_info *di)
 475 {
 476         u32 i, n;
 477
 478         di->sorted = calloc(di->nr_entries, sizeof(di->sorted[0]));
 479         if (!di->sorted)
 480                 return -1;
 481
 482         /* Get data for sorting: the offset and symbol index */
 483         for (i = 0, n = 0; i < di->nr_entries; i++) {
 484                 GElf_Rela rela;
 485                 u32 sym_idx;
 486
 487                 gelf_getrela(di->rela_dyn_data, i, &rela);
 488                 sym_idx = GELF_R_SYM(rela.r_info);
 489                 if (sym_idx) {
 490                         di->sorted[n].sym_idx = sym_idx;
 491                         di->sorted[n].offset = rela.r_offset;
 492                         n += 1;
 493                 }
 494         }
 495
 496         /* Sort by offset */
 497         di->nr_entries = n;
 498         qsort(di->sorted, n, sizeof(di->sorted[0]), cmp_offset);
 499
 500         return 0;
 501 }
 502
 503 static void get_rela_dyn_info(Elf *elf, GElf_Ehdr *ehdr, struct rela_dyn_info *di, Elf_Scn *scn)
 504 {
 505         GElf_Shdr rela_dyn_shdr;
 506         GElf_Shdr shdr;
 507
 508         di->plt_got_data = elf_getdata(scn, NULL);
 509
 510         scn = elf_section_by_name(elf, ehdr, &rela_dyn_shdr, ".rela.dyn", NULL);
 511         if (!scn || !rela_dyn_shdr.sh_link || !rela_dyn_shdr.sh_entsize)
 512                 return;
 513
 514         di->nr_entries = rela_dyn_shdr.sh_size / rela_dyn_shdr.sh_entsize;
 515         di->rela_dyn_data = elf_getdata(scn, NULL);
 516
 517         scn = elf_getscn(elf, rela_dyn_shdr.sh_link);
 518         if (!scn || !gelf_getshdr(scn, &shdr) || !shdr.sh_link)
 519                 return;
 520
 521         di->dynsym_data = elf_getdata(scn, NULL);
 522         di->dynstr_data = elf_getdata(elf_getscn(elf, shdr.sh_link), NULL);
 523
 524         if (!di->plt_got_data || !di->dynstr_data || !di->dynsym_data || !di->rela_dyn_data)
 525                 return;
 526
 527         /* Sort into offset order */
 528         sort_rela_dyn(di);
 529 }
 530
 531 /* Get instruction displacement from a plt entry for x86_64 */
 532 static u32 get_x86_64_plt_disp(const u8 *p)
 533 {
 534         u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa};
 535         int n = 0;
 536
 537         /* Skip endbr64 */
 538         if (!memcmp(p, endbr64, sizeof(endbr64)))
 539                 n += sizeof(endbr64);
 540         /* Skip bnd prefix */
 541         if (p[n] == 0xf2)
 542                 n += 1;
 543         /* jmp with 4-byte displacement */
 544         if (p[n] == 0xff && p[n + 1] == 0x25) {
 545                 u32 disp;
 546
 547                 n += 2;
 548                 /* Also add offset from start of entry to end of instruction */
 549                 memcpy(&disp, p + n, sizeof(disp));
 550                 return n + 4 + le32toh(disp);
 551         }
 552         return 0;
 553 }
 554
 555 static bool get_plt_got_name(GElf_Shdr *shdr, size_t i,
 556                              struct rela_dyn_info *di,
 557                              char *buf, size_t buf_sz)
 558 {
 559         struct rela_dyn vi, *vr;
 560         const char *sym_name;
 561         char *demangled;
 562         GElf_Sym sym;
 563         bool result;
 564         u32 disp;
 565
 566         if (!di->sorted)
 567                 return false;
 568
 569         disp = get_x86_64_plt_disp(di->plt_got_data->d_buf + i);
 570         if (!disp)
 571                 return false;
 572
 573         /* Compute target offset of the .plt.got entry */
 574         vi.offset = shdr->sh_offset + di->plt_got_data->d_off + i + disp;
 575
 576         /* Find that offset in .rela.dyn (sorted by offset) */
 577         vr = bsearch(&vi, di->sorted, di->nr_entries, sizeof(di->sorted[0]), cmp_offset);
 578         if (!vr)
 579                 return false;
 580
 581         /* Get the associated symbol */
 582         gelf_getsym(di->dynsym_data, vr->sym_idx, &sym);
 583         sym_name = elf_sym__name(&sym, di->dynstr_data);
 584         demangled = demangle_sym(di->dso, 0, sym_name);
 585         if (demangled != NULL)
 586                 sym_name = demangled;
 587
 588         snprintf(buf, buf_sz, "%s@plt", sym_name);
 589
 590         result = *sym_name;
 591
 592         free(demangled);
 593
 594         return result;
 595 }
 596
 597 static int dso__synthesize_plt_got_symbols(struct dso *dso, Elf *elf,
 598                                            GElf_Ehdr *ehdr,
 599                                            char *buf, size_t buf_sz)
 600 {
 601         struct rela_dyn_info di = { .dso = dso };
 602         struct symbol *sym;
 603         GElf_Shdr shdr;
 604         Elf_Scn *scn;
 605         int err = -1;
 606         size_t i;
 607
 608         scn = elf_section_by_name(elf, ehdr, &shdr, ".plt.got", NULL);
 609         if (!scn || !shdr.sh_entsize)
 610                 return 0;
 611
 612         if (ehdr->e_machine == EM_X86_64)
 613                 get_rela_dyn_info(elf, ehdr, &di, scn);
 614
 615         for (i = 0; i < shdr.sh_size; i += shdr.sh_entsize) {
 616                 if (!get_plt_got_name(&shdr, i, &di, buf, buf_sz))
 617                         snprintf(buf, buf_sz, "offset_%#" PRIx64 "@plt", (u64)shdr.sh_offset + i);
 618                 sym = symbol__new(shdr.sh_offset + i, shdr.sh_entsize, STB_GLOBAL, STT_FUNC, buf);
 619                 if (!sym)
 620                         goto out;
 621                 symbols__insert(&dso->symbols, sym);
 622         }
 623         err = 0;
 624 out:
 625         exit_rela_dyn(&di);
 626         return err;
 627 }
 628
 629 /*
 630  * We need to check if we have a .dynsym, so that we can handle the
 631  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 632  * .dynsym or .symtab).
 633  * And always look at the original dso, not at debuginfo packages, that
 634  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 635  */
 636 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 637 {
 638         uint32_t idx;
 639         GElf_Sym sym;
 640         u64 plt_offset, plt_header_size, plt_entry_size;
 641         GElf_Shdr shdr_plt, plt_sec_shdr;
 642         struct symbol *f, *plt_sym;
 643         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 644         Elf_Data *syms, *symstrs;
 645         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 646         GElf_Ehdr ehdr;
 647         char sympltname[1024];
 648         Elf *elf;
 649         int nr = 0, err = -1;
 650         struct rel_info ri = { .is_rela = false };
 651         bool lazy_plt;
 652
 653         elf = ss->elf;
 654         ehdr = ss->ehdr;
 655
 656         if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL))
 657                 return 0;
 658
 659         /*
 660          * A symbol from a previous section (e.g. .init) can have been expanded
 661          * by symbols__fixup_end() to overlap .plt. Truncate it before adding
 662          * a symbol for .plt header.
 663          */
 664         f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset);
 665         if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset)
 666                 f->end = shdr_plt.sh_offset;
 667
 668         if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size))
 669                 return 0;
 670
 671         /* Add a symbol for .plt header */
 672         plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt");
 673         if (!plt_sym)
 674                 goto out_elf_end;
 675         symbols__insert(&dso->symbols, plt_sym);
 676
 677         /* Only x86 has .plt.got */
 678         if (machine_is_x86(ehdr.e_machine) &&
 679             dso__synthesize_plt_got_symbols(dso, elf, &ehdr, sympltname, sizeof(sympltname)))
 680                 goto out_elf_end;
 681
 682         /* Only x86 has .plt.sec */
 683         if (machine_is_x86(ehdr.e_machine) &&
 684             elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) {
 685                 if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size))
 686                         return 0;
 687                 /* Extend .plt symbol to entire .plt */
 688                 plt_sym->end = plt_sym->start + shdr_plt.sh_size;
 689                 /* Use .plt.sec offset */
 690                 plt_offset = plt_sec_shdr.sh_offset;
 691                 lazy_plt = false;
 692         } else {
 693                 plt_offset = shdr_plt.sh_offset;
 694                 lazy_plt = true;
 695         }
 696
 697         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 698                                           ".rela.plt", NULL);
 699         if (scn_plt_rel == NULL) {
 700                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 701                                                   ".rel.plt", NULL);
 702                 if (scn_plt_rel == NULL)
 703                         return 0;
 704         }
 705
 706         if (shdr_rel_plt.sh_type != SHT_RELA &&
 707             shdr_rel_plt.sh_type != SHT_REL)
 708                 return 0;
 709
 710         if (!shdr_rel_plt.sh_link)
 711                 return 0;
 712
 713         if (shdr_rel_plt.sh_link == ss->dynsym_idx) {
 714                 scn_dynsym = ss->dynsym;
 715                 shdr_dynsym = ss->dynshdr;
 716         } else if (shdr_rel_plt.sh_link == ss->symtab_idx) {
 717                 /*
 718                  * A static executable can have a .plt due to IFUNCs, in which
 719                  * case .symtab is used not .dynsym.
 720                  */
 721                 scn_dynsym = ss->symtab;
 722                 shdr_dynsym = ss->symshdr;
 723         } else {
 724                 goto out_elf_end;
 725         }
 726
 727         if (!scn_dynsym)
 728                 return 0;
 729
 730         /*
 731          * Fetch the relocation section to find the idxes to the GOT
 732          * and the symbols in the .dynsym they refer to.
 733          */
 734         ri.reldata = elf_getdata(scn_plt_rel, NULL);
 735         if (!ri.reldata)
 736                 goto out_elf_end;
 737
 738         syms = elf_getdata(scn_dynsym, NULL);
 739         if (syms == NULL)
 740                 goto out_elf_end;
 741
 742         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 743         if (scn_symstrs == NULL)
 744                 goto out_elf_end;
 745
 746         symstrs = elf_getdata(scn_symstrs, NULL);
 747         if (symstrs == NULL)
 748                 goto out_elf_end;
 749
 750         if (symstrs->d_size == 0)
 751                 goto out_elf_end;
 752
 753         ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 754
 755         ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;
 756
 757         if (lazy_plt) {
 758                 /*
 759                  * Assume a .plt with the same number of entries as the number
 760                  * of relocation entries is not lazy and does not have a header.
 761                  */
 762                 if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size)
 763                         dso__delete_symbol(dso, plt_sym);
 764                 else
 765                         plt_offset += plt_header_size;
 766         }
 767
 768         /*
 769          * x86 doesn't insert IFUNC relocations in .plt order, so sort to get
 770          * back in order.
 771          */
 772         if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri))
 773                 goto out_elf_end;
 774
 775         for (idx = 0; idx < ri.nr_entries; idx++) {
 776                 const char *elf_name = NULL;
 777                 char *demangled = NULL;
 778
 779                 gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym);
 780
 781                 elf_name = elf_sym__name(&sym, symstrs);
 782                 demangled = demangle_sym(dso, 0, elf_name);
 783                 if (demangled)
 784                         elf_name = demangled;
 785                 if (*elf_name)
 786                         snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name);
 787                 else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname)))
 788                         snprintf(sympltname, sizeof(sympltname),
 789                                  "offset_%#" PRIx64 "@plt", plt_offset);
 790                 free(demangled);
 791
 792                 f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname);
 793                 if (!f)
 794                         goto out_elf_end;
 795
 796                 plt_offset += plt_entry_size;
 797                 symbols__insert(&dso->symbols, f);
 798                 ++nr;
 799         }
 800
 801         err = 0;
 802 out_elf_end:
 803         exit_rel(&ri);
 804         if (err == 0)
 805                 return nr;
 806         pr_debug("%s: problems reading %s PLT info.\n",
 807                  __func__, dso->long_name);
 808         return 0;
 809 }
 810
 811 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 812 {
 813         return demangle_sym(dso, kmodule, elf_name);
 814 }
 815
 816 /*
 817  * Align offset to 4 bytes as needed for note name and descriptor data.
 818  */
 819 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 820
 821 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 822 {
 823         int err = -1;
 824         GElf_Ehdr ehdr;
 825         GElf_Shdr shdr;
 826         Elf_Data *data;
 827         Elf_Scn *sec;
 828         Elf_Kind ek;
 829         void *ptr;
 830
 831         if (size < BUILD_ID_SIZE)
 832                 goto out;
 833
 834         ek = elf_kind(elf);
 835         if (ek != ELF_K_ELF)
 836                 goto out;
 837
 838         if (gelf_getehdr(elf, &ehdr) == NULL) {
 839                 pr_err("%s: cannot get elf header.\n", __func__);
 840                 goto out;
 841         }
 842
 843         /*
 844          * Check following sections for notes:
 845          *   '.note.gnu.build-id'
 846          *   '.notes'
 847          *   '.note' (VDSO specific)
 848          */
 849         do {
 850                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 851                                           ".note.gnu.build-id", NULL);
 852                 if (sec)
 853                         break;
 854
 855                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 856                                           ".notes", NULL);
 857                 if (sec)
 858                         break;
 859
 860                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 861                                           ".note", NULL);
 862                 if (sec)
 863                         break;
 864
 865                 return err;
 866
 867         } while (0);
 868
 869         data = elf_getdata(sec, NULL);
 870         if (data == NULL)
 871                 goto out;
 872
 873         ptr = data->d_buf;
 874         while (ptr < (data->d_buf + data->d_size)) {
 875                 GElf_Nhdr *nhdr = ptr;
 876                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 877                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 878                 const char *name;
 879
 880                 ptr += sizeof(*nhdr);
 881                 name = ptr;
 882                 ptr += namesz;
 883                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 884                     nhdr->n_namesz == sizeof("GNU")) {
 885                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 886                                 size_t sz = min(size, descsz);
 887                                 memcpy(bf, ptr, sz);
 888                                 memset(bf + sz, 0, size - sz);
 889                                 err = descsz;
 890                                 break;
 891                         }
 892                 }
 893                 ptr += descsz;
 894         }
 895
 896 out:
 897         return err;
 898 }
 899
 900 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT
 901
 902 static int read_build_id(const char *filename, struct build_id *bid)
 903 {
 904         size_t size = sizeof(bid->data);
 905         int err = -1;
 906         bfd *abfd;
 907
 908         abfd = bfd_openr(filename, NULL);
 909         if (!abfd)
 910                 return -1;
 911
 912         if (!bfd_check_format(abfd, bfd_object)) {
 913                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 914                 goto out_close;
 915         }
 916
 917         if (!abfd->build_id || abfd->build_id->size > size)
 918                 goto out_close;
 919
 920         memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
 921         memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
 922         err = bid->size = abfd->build_id->size;
 923
 924 out_close:
 925         bfd_close(abfd);
 926         return err;
 927 }
 928
 929 #else // HAVE_LIBBFD_BUILDID_SUPPORT
 930
 931 static int read_build_id(const char *filename, struct build_id *bid)
 932 {
 933         size_t size = sizeof(bid->data);
 934         int fd, err = -1;
 935         Elf *elf;
 936
 937         if (size < BUILD_ID_SIZE)
 938                 goto out;
 939
 940         fd = open(filename, O_RDONLY);
 941         if (fd < 0)
 942                 goto out;
 943
 944         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 945         if (elf == NULL) {
 946                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 947                 goto out_close;
 948         }
 949
 950         err = elf_read_build_id(elf, bid->data, size);
 951         if (err > 0)
 952                 bid->size = err;
 953
 954         elf_end(elf);
 955 out_close:
 956         close(fd);
 957 out:
 958         return err;
 959 }
 960
 961 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
 962
 963 int filename__read_build_id(const char *filename, struct build_id *bid)
 964 {
 965         struct kmod_path m = { .name = NULL, };
 966         char path[PATH_MAX];
 967         int err;
 968
 969         if (!filename)
 970                 return -EFAULT;
 971
 972         err = kmod_path__parse(&m, filename);
 973         if (err)
 974                 return -1;
 975
 976         if (m.comp) {
 977                 int error = 0, fd;
 978
 979                 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
 980                 if (fd < 0) {
 981                         pr_debug("Failed to decompress (error %d) %s\n",
 982                                  error, filename);
 983                         return -1;
 984                 }
 985                 close(fd);
 986                 filename = path;
 987         }
 988
 989         err = read_build_id(filename, bid);
 990
 991         if (m.comp)
 992                 unlink(filename);
 993         return err;
 994 }
 995
 996 int sysfs__read_build_id(const char *filename, struct build_id *bid)
 997 {
 998         size_t size = sizeof(bid->data);
 999         int fd, err = -1;
1000
1001         fd = open(filename, O_RDONLY);
1002         if (fd < 0)
1003                 goto out;
1004
1005         while (1) {
1006                 char bf[BUFSIZ];
1007                 GElf_Nhdr nhdr;
1008                 size_t namesz, descsz;
1009
1010                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
1011                         break;
1012
1013                 namesz = NOTE_ALIGN(nhdr.n_namesz);
1014                 descsz = NOTE_ALIGN(nhdr.n_descsz);
1015                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
1016                     nhdr.n_namesz == sizeof("GNU")) {
1017                         if (read(fd, bf, namesz) != (ssize_t)namesz)
1018                                 break;
1019                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
1020                                 size_t sz = min(descsz, size);
1021                                 if (read(fd, bid->data, sz) == (ssize_t)sz) {
1022                                         memset(bid->data + sz, 0, size - sz);
1023                                         bid->size = sz;
1024                                         err = 0;
1025                                         break;
1026                                 }
1027                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
1028                                 break;
1029                 } else {
1030                         int n = namesz + descsz;
1031
1032                         if (n > (int)sizeof(bf)) {
1033                                 n = sizeof(bf);
1034                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
1035                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
1036                         }
1037                         if (read(fd, bf, n) != n)
1038                                 break;
1039                 }
1040         }
1041         close(fd);
1042 out:
1043         return err;
1044 }
1045
1046 #ifdef HAVE_LIBBFD_SUPPORT
1047
1048 int filename__read_debuglink(const char *filename, char *debuglink,
1049                              size_t size)
1050 {
1051         int err = -1;
1052         asection *section;
1053         bfd *abfd;
1054
1055         abfd = bfd_openr(filename, NULL);
1056         if (!abfd)
1057                 return -1;
1058
1059         if (!bfd_check_format(abfd, bfd_object)) {
1060                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
1061                 goto out_close;
1062         }
1063
1064         section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
1065         if (!section)
1066                 goto out_close;
1067
1068         if (section->size > size)
1069                 goto out_close;
1070
1071         if (!bfd_get_section_contents(abfd, section, debuglink, 0,
1072                                       section->size))
1073                 goto out_close;
1074
1075         err = 0;
1076
1077 out_close:
1078         bfd_close(abfd);
1079         return err;
1080 }
1081
1082 #else
1083
1084 int filename__read_debuglink(const char *filename, char *debuglink,
1085                              size_t size)
1086 {
1087         int fd, err = -1;
1088         Elf *elf;
1089         GElf_Ehdr ehdr;
1090         GElf_Shdr shdr;
1091         Elf_Data *data;
1092         Elf_Scn *sec;
1093         Elf_Kind ek;
1094
1095         fd = open(filename, O_RDONLY);
1096         if (fd < 0)
1097                 goto out;
1098
1099         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1100         if (elf == NULL) {
1101                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
1102                 goto out_close;
1103         }
1104
1105         ek = elf_kind(elf);
1106         if (ek != ELF_K_ELF)
1107                 goto out_elf_end;
1108
1109         if (gelf_getehdr(elf, &ehdr) == NULL) {
1110                 pr_err("%s: cannot get elf header.\n", __func__);
1111                 goto out_elf_end;
1112         }
1113
1114         sec = elf_section_by_name(elf, &ehdr, &shdr,
1115                                   ".gnu_debuglink", NULL);
1116         if (sec == NULL)
1117                 goto out_elf_end;
1118
1119         data = elf_getdata(sec, NULL);
1120         if (data == NULL)
1121                 goto out_elf_end;
1122
1123         /* the start of this section is a zero-terminated string */
1124         strncpy(debuglink, data->d_buf, size);
1125
1126         err = 0;
1127
1128 out_elf_end:
1129         elf_end(elf);
1130 out_close:
1131         close(fd);
1132 out:
1133         return err;
1134 }
1135
1136 #endif
1137
1138 static int dso__swap_init(struct dso *dso, unsigned char eidata)
1139 {
1140         static unsigned int const endian = 1;
1141
1142         dso->needs_swap = DSO_SWAP__NO;
1143
1144         switch (eidata) {
1145         case ELFDATA2LSB:
1146                 /* We are big endian, DSO is little endian. */
1147                 if (*(unsigned char const *)&endian != 1)
1148                         dso->needs_swap = DSO_SWAP__YES;
1149                 break;
1150
1151         case ELFDATA2MSB:
1152                 /* We are little endian, DSO is big endian. */
1153                 if (*(unsigned char const *)&endian != 0)
1154                         dso->needs_swap = DSO_SWAP__YES;
1155                 break;
1156
1157         default:
1158                 pr_err("unrecognized DSO data encoding %d\n", eidata);
1159                 return -EINVAL;
1160         }
1161
1162         return 0;
1163 }
1164
1165 bool symsrc__possibly_runtime(struct symsrc *ss)
1166 {
1167         return ss->dynsym || ss->opdsec;
1168 }
1169
1170 bool symsrc__has_symtab(struct symsrc *ss)
1171 {
1172         return ss->symtab != NULL;
1173 }
1174
1175 void symsrc__destroy(struct symsrc *ss)
1176 {
1177         zfree(&ss->name);
1178         elf_end(ss->elf);
1179         close(ss->fd);
1180 }
1181
1182 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
1183 {
1184         /*
1185          * Usually vmlinux is an ELF file with type ET_EXEC for most
1186          * architectures; except Arm64 kernel is linked with option
1187          * '-share', so need to check type ET_DYN.
1188          */
1189         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
1190                ehdr.e_type == ET_DYN;
1191 }
1192
1193 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
1194                  enum dso_binary_type type)
1195 {
1196         GElf_Ehdr ehdr;
1197         Elf *elf;
1198         int fd;
1199
1200         if (dso__needs_decompress(dso)) {
1201                 fd = dso__decompress_kmodule_fd(dso, name);
1202                 if (fd < 0)
1203                         return -1;
1204
1205                 type = dso->symtab_type;
1206         } else {
1207                 fd = open(name, O_RDONLY);
1208                 if (fd < 0) {
1209                         dso->load_errno = errno;
1210                         return -1;
1211                 }
1212         }
1213
1214         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1215         if (elf == NULL) {
1216                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
1217                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
1218                 goto out_close;
1219         }
1220
1221         if (gelf_getehdr(elf, &ehdr) == NULL) {
1222                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
1223                 pr_debug("%s: cannot get elf header.\n", __func__);
1224                 goto out_elf_end;
1225         }
1226
1227         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
1228                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
1229                 goto out_elf_end;
1230         }
1231
1232         /* Always reject images with a mismatched build-id: */
1233         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
1234                 u8 build_id[BUILD_ID_SIZE];
1235                 struct build_id bid;
1236                 int size;
1237
1238                 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
1239                 if (size <= 0) {
1240                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
1241                         goto out_elf_end;
1242                 }
1243
1244                 build_id__init(&bid, build_id, size);
1245                 if (!dso__build_id_equal(dso, &bid)) {
1246                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
1247                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
1248                         goto out_elf_end;
1249                 }
1250         }
1251
1252         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1253
1254         ss->symtab_idx = 0;
1255         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
1256                         &ss->symtab_idx);
1257         if (ss->symshdr.sh_type != SHT_SYMTAB)
1258                 ss->symtab = NULL;
1259
1260         ss->dynsym_idx = 0;
1261         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
1262                         &ss->dynsym_idx);
1263         if (ss->dynshdr.sh_type != SHT_DYNSYM)
1264                 ss->dynsym = NULL;
1265
1266         ss->opdidx = 0;
1267         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
1268                         &ss->opdidx);
1269         if (ss->opdshdr.sh_type != SHT_PROGBITS)
1270                 ss->opdsec = NULL;
1271
1272         if (dso->kernel == DSO_SPACE__USER)
1273                 ss->adjust_symbols = true;
1274         else
1275                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
1276
1277         ss->name   = strdup(name);
1278         if (!ss->name) {
1279                 dso->load_errno = errno;
1280                 goto out_elf_end;
1281         }
1282
1283         ss->elf    = elf;
1284         ss->fd     = fd;
1285         ss->ehdr   = ehdr;
1286         ss->type   = type;
1287
1288         return 0;
1289
1290 out_elf_end:
1291         elf_end(elf);
1292 out_close:
1293         close(fd);
1294         return -1;
1295 }
1296
1297 /**
1298  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
1299  * @kmap: kernel maps and relocation reference symbol
1300  *
1301  * This function returns %true if we are dealing with the kernel maps and the
1302  * relocation reference symbol has not yet been found.  Otherwise %false is
1303  * returned.
1304  */
1305 static bool ref_reloc_sym_not_found(struct kmap *kmap)
1306 {
1307         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
1308                !kmap->ref_reloc_sym->unrelocated_addr;
1309 }
1310
1311 /**
1312  * ref_reloc - kernel relocation offset.
1313  * @kmap: kernel maps and relocation reference symbol
1314  *
1315  * This function returns the offset of kernel addresses as determined by using
1316  * the relocation reference symbol i.e. if the kernel has not been relocated
1317  * then the return value is zero.
1318  */
1319 static u64 ref_reloc(struct kmap *kmap)
1320 {
1321         if (kmap && kmap->ref_reloc_sym &&
1322             kmap->ref_reloc_sym->unrelocated_addr)
1323                 return kmap->ref_reloc_sym->addr -
1324                        kmap->ref_reloc_sym->unrelocated_addr;
1325         return 0;
1326 }
1327
1328 void __weak arch__sym_update(struct symbol *s __maybe_unused,
1329                 GElf_Sym *sym __maybe_unused) { }
1330
1331 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
1332                                       GElf_Sym *sym, GElf_Shdr *shdr,
1333                                       struct maps *kmaps, struct kmap *kmap,
1334                                       struct dso **curr_dsop, struct map **curr_mapp,
1335                                       const char *section_name,
1336                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
1337 {
1338         struct dso *curr_dso = *curr_dsop;
1339         struct map *curr_map;
1340         char dso_name[PATH_MAX];
1341
1342         /* Adjust symbol to map to file offset */
1343         if (adjust_kernel_syms)
1344                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
1345
1346         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
1347                 return 0;
1348
1349         if (strcmp(section_name, ".text") == 0) {
1350                 /*
1351                  * The initial kernel mapping is based on
1352                  * kallsyms and identity maps.  Overwrite it to
1353                  * map to the kernel dso.
1354                  */
1355                 if (*remap_kernel && dso->kernel && !kmodule) {
1356                         *remap_kernel = false;
1357                         map->start = shdr->sh_addr + ref_reloc(kmap);
1358                         map->end = map__start(map) + shdr->sh_size;
1359                         map->pgoff = shdr->sh_offset;
1360                         map->map_ip = map__dso_map_ip;
1361                         map->unmap_ip = map__dso_unmap_ip;
1362                         /* Ensure maps are correctly ordered */
1363                         if (kmaps) {
1364                                 int err;
1365
1366                                 map__get(map);
1367                                 maps__remove(kmaps, map);
1368                                 err = maps__insert(kmaps, map);
1369                                 map__put(map);
1370                                 if (err)
1371                                         return err;
1372                         }
1373                 }
1374
1375                 /*
1376                  * The initial module mapping is based on
1377                  * /proc/modules mapped to offset zero.
1378                  * Overwrite it to map to the module dso.
1379                  */
1380                 if (*remap_kernel && kmodule) {
1381                         *remap_kernel = false;
1382                         map->pgoff = shdr->sh_offset;
1383                 }
1384
1385                 *curr_mapp = map;
1386                 *curr_dsop = dso;
1387                 return 0;
1388         }
1389
1390         if (!kmap)
1391                 return 0;
1392
1393         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
1394
1395         curr_map = maps__find_by_name(kmaps, dso_name);
1396         if (curr_map == NULL) {
1397                 u64 start = sym->st_value;
1398
1399                 if (kmodule)
1400                         start += map__start(map) + shdr->sh_offset;
1401
1402                 curr_dso = dso__new(dso_name);
1403                 if (curr_dso == NULL)
1404                         return -1;
1405                 curr_dso->kernel = dso->kernel;
1406                 curr_dso->long_name = dso->long_name;
1407                 curr_dso->long_name_len = dso->long_name_len;
1408                 curr_map = map__new2(start, curr_dso);
1409                 dso__put(curr_dso);
1410                 if (curr_map == NULL)
1411                         return -1;
1412
1413                 if (curr_dso->kernel)
1414                         map__kmap(curr_map)->kmaps = kmaps;
1415
1416                 if (adjust_kernel_syms) {
1417                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
1418                         curr_map->end    = map__start(curr_map) + shdr->sh_size;
1419                         curr_map->pgoff  = shdr->sh_offset;
1420                 } else {
1421                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
1422                 }
1423                 curr_dso->symtab_type = dso->symtab_type;
1424                 if (maps__insert(kmaps, curr_map))
1425                         return -1;
1426                 /*
1427                  * Add it before we drop the reference to curr_map, i.e. while
1428                  * we still are sure to have a reference to this DSO via
1429                  * *curr_map->dso.
1430                  */
1431                 dsos__add(&maps__machine(kmaps)->dsos, curr_dso);
1432                 /* kmaps already got it */
1433                 map__put(curr_map);
1434                 dso__set_loaded(curr_dso);
1435                 *curr_mapp = curr_map;
1436                 *curr_dsop = curr_dso;
1437         } else
1438                 *curr_dsop = map__dso(curr_map);
1439
1440         return 0;
1441 }
1442
1443 static int
1444 dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1445                        struct symsrc *runtime_ss, int kmodule, int dynsym)
1446 {
1447         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
1448         struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1449         struct map *curr_map = map;
1450         struct dso *curr_dso = dso;
1451         Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
1452         uint32_t nr_syms;
1453         int err = -1;
1454         uint32_t idx;
1455         GElf_Ehdr ehdr;
1456         GElf_Shdr shdr;
1457         GElf_Shdr tshdr;
1458         Elf_Data *syms, *opddata = NULL;
1459         GElf_Sym sym;
1460         Elf_Scn *sec, *sec_strndx;
1461         Elf *elf;
1462         int nr = 0;
1463         bool remap_kernel = false, adjust_kernel_syms = false;
1464
1465         if (kmap && !kmaps)
1466                 return -1;
1467
1468         elf = syms_ss->elf;
1469         ehdr = syms_ss->ehdr;
1470         if (dynsym) {
1471                 sec  = syms_ss->dynsym;
1472                 shdr = syms_ss->dynshdr;
1473         } else {
1474                 sec =  syms_ss->symtab;
1475                 shdr = syms_ss->symshdr;
1476         }
1477
1478         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1479                                 ".text", NULL))
1480                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1481
1482         if (runtime_ss->opdsec)
1483                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1484
1485         syms = elf_getdata(sec, NULL);
1486         if (syms == NULL)
1487                 goto out_elf_end;
1488
1489         sec = elf_getscn(elf, shdr.sh_link);
1490         if (sec == NULL)
1491                 goto out_elf_end;
1492
1493         symstrs = elf_getdata(sec, NULL);
1494         if (symstrs == NULL)
1495                 goto out_elf_end;
1496
1497         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1498         if (sec_strndx == NULL)
1499                 goto out_elf_end;
1500
1501         secstrs_run = elf_getdata(sec_strndx, NULL);
1502         if (secstrs_run == NULL)
1503                 goto out_elf_end;
1504
1505         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
1506         if (sec_strndx == NULL)
1507                 goto out_elf_end;
1508
1509         secstrs_sym = elf_getdata(sec_strndx, NULL);
1510         if (secstrs_sym == NULL)
1511                 goto out_elf_end;
1512
1513         nr_syms = shdr.sh_size / shdr.sh_entsize;
1514
1515         memset(&sym, 0, sizeof(sym));
1516
1517         /*
1518          * The kernel relocation symbol is needed in advance in order to adjust
1519          * kernel maps correctly.
1520          */
1521         if (ref_reloc_sym_not_found(kmap)) {
1522                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1523                         const char *elf_name = elf_sym__name(&sym, symstrs);
1524
1525                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1526                                 continue;
1527                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1528                         map->reloc = kmap->ref_reloc_sym->addr -
1529                                      kmap->ref_reloc_sym->unrelocated_addr;
1530                         break;
1531                 }
1532         }
1533
1534         /*
1535          * Handle any relocation of vdso necessary because older kernels
1536          * attempted to prelink vdso to its virtual address.
1537          */
1538         if (dso__is_vdso(dso))
1539                 map->reloc = map__start(map) - dso->text_offset;
1540
1541         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1542         /*
1543          * Initial kernel and module mappings do not map to the dso.
1544          * Flag the fixups.
1545          */
1546         if (dso->kernel) {
1547                 remap_kernel = true;
1548                 adjust_kernel_syms = dso->adjust_symbols;
1549         }
1550         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1551                 struct symbol *f;
1552                 const char *elf_name = elf_sym__name(&sym, symstrs);
1553                 char *demangled = NULL;
1554                 int is_label = elf_sym__is_label(&sym);
1555                 const char *section_name;
1556                 bool used_opd = false;
1557
1558                 if (!is_label && !elf_sym__filter(&sym))
1559                         continue;
1560
1561                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1562                  * don't identify functions, so will confuse the profile
1563                  * output: */
1564                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1565                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1566                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1567                                 continue;
1568                 }
1569
1570                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1571                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1572                         u64 *opd = opddata->d_buf + offset;
1573                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1574                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1575                                         sym.st_value);
1576                         used_opd = true;
1577                 }
1578
1579                 /*
1580                  * When loading symbols in a data mapping, ABS symbols (which
1581                  * has a value of SHN_ABS in its st_shndx) failed at
1582                  * elf_getscn().  And it marks the loading as a failure so
1583                  * already loaded symbols cannot be fixed up.
1584                  *
1585                  * I'm not sure what should be done. Just ignore them for now.
1586                  * - Namhyung Kim
1587                  */
1588                 if (sym.st_shndx == SHN_ABS)
1589                         continue;
1590
1591                 sec = elf_getscn(syms_ss->elf, sym.st_shndx);
1592                 if (!sec)
1593                         goto out_elf_end;
1594
1595                 gelf_getshdr(sec, &shdr);
1596
1597                 /*
1598                  * If the attribute bit SHF_ALLOC is not set, the section
1599                  * doesn't occupy memory during process execution.
1600                  * E.g. ".gnu.warning.*" section is used by linker to generate
1601                  * warnings when calling deprecated functions, the symbols in
1602                  * the section aren't loaded to memory during process execution,
1603                  * so skip them.
1604                  */
1605                 if (!(shdr.sh_flags & SHF_ALLOC))
1606                         continue;
1607
1608                 secstrs = secstrs_sym;
1609
1610                 /*
1611                  * We have to fallback to runtime when syms' section header has
1612                  * NOBITS set. NOBITS results in file offset (sh_offset) not
1613                  * being incremented. So sh_offset used below has different
1614                  * values for syms (invalid) and runtime (valid).
1615                  */
1616                 if (shdr.sh_type == SHT_NOBITS) {
1617                         sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1618                         if (!sec)
1619                                 goto out_elf_end;
1620
1621                         gelf_getshdr(sec, &shdr);
1622                         secstrs = secstrs_run;
1623                 }
1624
1625                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1626                         continue;
1627
1628                 section_name = elf_sec__name(&shdr, secstrs);
1629
1630                 /* On ARM, symbols for thumb functions have 1 added to
1631                  * the symbol address as a flag - remove it */
1632                 if ((ehdr.e_machine == EM_ARM) &&
1633                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1634                     (sym.st_value & 1))
1635                         --sym.st_value;
1636
1637                 if (dso->kernel) {
1638                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1639                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1640                                 goto out_elf_end;
1641                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1642                            (!used_opd && syms_ss->adjust_symbols)) {
1643                         GElf_Phdr phdr;
1644
1645                         if (elf_read_program_header(runtime_ss->elf,
1646                                                     (u64)sym.st_value, &phdr)) {
1647                                 pr_debug4("%s: failed to find program header for "
1648                                            "symbol: %s st_value: %#" PRIx64 "\n",
1649                                            __func__, elf_name, (u64)sym.st_value);
1650                                 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1651                                         "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n",
1652                                         __func__, (u64)sym.st_value, (u64)shdr.sh_addr,
1653                                         (u64)shdr.sh_offset);
1654                                 /*
1655                                  * Fail to find program header, let's rollback
1656                                  * to use shdr.sh_addr and shdr.sh_offset to
1657                                  * calibrate symbol's file address, though this
1658                                  * is not necessary for normal C ELF file, we
1659                                  * still need to handle java JIT symbols in this
1660                                  * case.
1661                                  */
1662                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1663                         } else {
1664                                 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1665                                         "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
1666                                         __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
1667                                         (u64)phdr.p_offset);
1668                                 sym.st_value -= phdr.p_vaddr - phdr.p_offset;
1669                         }
1670                 }
1671
1672                 demangled = demangle_sym(dso, kmodule, elf_name);
1673                 if (demangled != NULL)
1674                         elf_name = demangled;
1675
1676                 f = symbol__new(sym.st_value, sym.st_size,
1677                                 GELF_ST_BIND(sym.st_info),
1678                                 GELF_ST_TYPE(sym.st_info), elf_name);
1679                 free(demangled);
1680                 if (!f)
1681                         goto out_elf_end;
1682
1683                 arch__sym_update(f, &sym);
1684
1685                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1686                 nr++;
1687         }
1688
1689         /*
1690          * For misannotated, zeroed, ASM function sizes.
1691          */
1692         if (nr > 0) {
1693                 symbols__fixup_end(&dso->symbols, false);
1694                 symbols__fixup_duplicate(&dso->symbols);
1695                 if (kmap) {
1696                         /*
1697                          * We need to fixup this here too because we create new
1698                          * maps here, for things like vsyscall sections.
1699                          */
1700                         maps__fixup_end(kmaps);
1701                 }
1702         }
1703         err = nr;
1704 out_elf_end:
1705         return err;
1706 }
1707
1708 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1709                   struct symsrc *runtime_ss, int kmodule)
1710 {
1711         int nr = 0;
1712         int err = -1;
1713
1714         dso->symtab_type = syms_ss->type;
1715         dso->is_64_bit = syms_ss->is_64_bit;
1716         dso->rel = syms_ss->ehdr.e_type == ET_REL;
1717
1718         /*
1719          * Modules may already have symbols from kallsyms, but those symbols
1720          * have the wrong values for the dso maps, so remove them.
1721          */
1722         if (kmodule && syms_ss->symtab)
1723                 symbols__delete(&dso->symbols);
1724
1725         if (!syms_ss->symtab) {
1726                 /*
1727                  * If the vmlinux is stripped, fail so we will fall back
1728                  * to using kallsyms. The vmlinux runtime symbols aren't
1729                  * of much use.
1730                  */
1731                 if (dso->kernel)
1732                         return err;
1733         } else  {
1734                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1735                                              kmodule, 0);
1736                 if (err < 0)
1737                         return err;
1738                 nr = err;
1739         }
1740
1741         if (syms_ss->dynsym) {
1742                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1743                                              kmodule, 1);
1744                 if (err < 0)
1745                         return err;
1746                 err += nr;
1747         }
1748
1749         return err;
1750 }
1751
1752 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1753 {
1754         GElf_Phdr phdr;
1755         size_t i, phdrnum;
1756         int err;
1757         u64 sz;
1758
1759         if (elf_getphdrnum(elf, &phdrnum))
1760                 return -1;
1761
1762         for (i = 0; i < phdrnum; i++) {
1763                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1764                         return -1;
1765                 if (phdr.p_type != PT_LOAD)
1766                         continue;
1767                 if (exe) {
1768                         if (!(phdr.p_flags & PF_X))
1769                                 continue;
1770                 } else {
1771                         if (!(phdr.p_flags & PF_R))
1772                                 continue;
1773                 }
1774                 sz = min(phdr.p_memsz, phdr.p_filesz);
1775                 if (!sz)
1776                         continue;
1777                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1778                 if (err)
1779                         return err;
1780         }
1781         return 0;
1782 }
1783
1784 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1785                     bool *is_64_bit)
1786 {
1787         int err;
1788         Elf *elf;
1789
1790         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1791         if (elf == NULL)
1792                 return -1;
1793
1794         if (is_64_bit)
1795                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1796
1797         err = elf_read_maps(elf, exe, mapfn, data);
1798
1799         elf_end(elf);
1800         return err;
1801 }
1802
1803 enum dso_type dso__type_fd(int fd)
1804 {
1805         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1806         GElf_Ehdr ehdr;
1807         Elf_Kind ek;
1808         Elf *elf;
1809
1810         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1811         if (elf == NULL)
1812                 goto out;
1813
1814         ek = elf_kind(elf);
1815         if (ek != ELF_K_ELF)
1816                 goto out_end;
1817
1818         if (gelf_getclass(elf) == ELFCLASS64) {
1819                 dso_type = DSO__TYPE_64BIT;
1820                 goto out_end;
1821         }
1822
1823         if (gelf_getehdr(elf, &ehdr) == NULL)
1824                 goto out_end;
1825
1826         if (ehdr.e_machine == EM_X86_64)
1827                 dso_type = DSO__TYPE_X32BIT;
1828         else
1829                 dso_type = DSO__TYPE_32BIT;
1830 out_end:
1831         elf_end(elf);
1832 out:
1833         return dso_type;
1834 }
1835
1836 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1837 {
1838         ssize_t r;
1839         size_t n;
1840         int err = -1;
1841         char *buf = malloc(page_size);
1842
1843         if (buf == NULL)
1844                 return -1;
1845
1846         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1847                 goto out;
1848
1849         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1850                 goto out;
1851
1852         while (len) {
1853                 n = page_size;
1854                 if (len < n)
1855                         n = len;
1856                 /* Use read because mmap won't work on proc files */
1857                 r = read(from, buf, n);
1858                 if (r < 0)
1859                         goto out;
1860                 if (!r)
1861                         break;
1862                 n = r;
1863                 r = write(to, buf, n);
1864                 if (r < 0)
1865                         goto out;
1866                 if ((size_t)r != n)
1867                         goto out;
1868                 len -= n;
1869         }
1870
1871         err = 0;
1872 out:
1873         free(buf);
1874         return err;
1875 }
1876
1877 struct kcore {
1878         int fd;
1879         int elfclass;
1880         Elf *elf;
1881         GElf_Ehdr ehdr;
1882 };
1883
1884 static int kcore__open(struct kcore *kcore, const char *filename)
1885 {
1886         GElf_Ehdr *ehdr;
1887
1888         kcore->fd = open(filename, O_RDONLY);
1889         if (kcore->fd == -1)
1890                 return -1;
1891
1892         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1893         if (!kcore->elf)
1894                 goto out_close;
1895
1896         kcore->elfclass = gelf_getclass(kcore->elf);
1897         if (kcore->elfclass == ELFCLASSNONE)
1898                 goto out_end;
1899
1900         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1901         if (!ehdr)
1902                 goto out_end;
1903
1904         return 0;
1905
1906 out_end:
1907         elf_end(kcore->elf);
1908 out_close:
1909         close(kcore->fd);
1910         return -1;
1911 }
1912
1913 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1914                        bool temp)
1915 {
1916         kcore->elfclass = elfclass;
1917
1918         if (temp)
1919                 kcore->fd = mkstemp(filename);
1920         else
1921                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1922         if (kcore->fd == -1)
1923                 return -1;
1924
1925         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1926         if (!kcore->elf)
1927                 goto out_close;
1928
1929         if (!gelf_newehdr(kcore->elf, elfclass))
1930                 goto out_end;
1931
1932         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1933
1934         return 0;
1935
1936 out_end:
1937         elf_end(kcore->elf);
1938 out_close:
1939         close(kcore->fd);
1940         unlink(filename);
1941         return -1;
1942 }
1943
1944 static void kcore__close(struct kcore *kcore)
1945 {
1946         elf_end(kcore->elf);
1947         close(kcore->fd);
1948 }
1949
1950 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1951 {
1952         GElf_Ehdr *ehdr = &to->ehdr;
1953         GElf_Ehdr *kehdr = &from->ehdr;
1954
1955         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1956         ehdr->e_type      = kehdr->e_type;
1957         ehdr->e_machine   = kehdr->e_machine;
1958         ehdr->e_version   = kehdr->e_version;
1959         ehdr->e_entry     = 0;
1960         ehdr->e_shoff     = 0;
1961         ehdr->e_flags     = kehdr->e_flags;
1962         ehdr->e_phnum     = count;
1963         ehdr->e_shentsize = 0;
1964         ehdr->e_shnum     = 0;
1965         ehdr->e_shstrndx  = 0;
1966
1967         if (from->elfclass == ELFCLASS32) {
1968                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1969                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1970                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1971         } else {
1972                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1973                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1974                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1975         }
1976
1977         if (!gelf_update_ehdr(to->elf, ehdr))
1978                 return -1;
1979
1980         if (!gelf_newphdr(to->elf, count))
1981                 return -1;
1982
1983         return 0;
1984 }
1985
1986 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1987                            u64 addr, u64 len)
1988 {
1989         GElf_Phdr phdr = {
1990                 .p_type         = PT_LOAD,
1991                 .p_flags        = PF_R | PF_W | PF_X,
1992                 .p_offset       = offset,
1993                 .p_vaddr        = addr,
1994                 .p_paddr        = 0,
1995                 .p_filesz       = len,
1996                 .p_memsz        = len,
1997                 .p_align        = page_size,
1998         };
1999
2000         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
2001                 return -1;
2002
2003         return 0;
2004 }
2005
2006 static off_t kcore__write(struct kcore *kcore)
2007 {
2008         return elf_update(kcore->elf, ELF_C_WRITE);
2009 }
2010
2011 struct phdr_data {
2012         off_t offset;
2013         off_t rel;
2014         u64 addr;
2015         u64 len;
2016         struct list_head node;
2017         struct phdr_data *remaps;
2018 };
2019
2020 struct sym_data {
2021         u64 addr;
2022         struct list_head node;
2023 };
2024
2025 struct kcore_copy_info {
2026         u64 stext;
2027         u64 etext;
2028         u64 first_symbol;
2029         u64 last_symbol;
2030         u64 first_module;
2031         u64 first_module_symbol;
2032         u64 last_module_symbol;
2033         size_t phnum;
2034         struct list_head phdrs;
2035         struct list_head syms;
2036 };
2037
2038 #define kcore_copy__for_each_phdr(k, p) \
2039         list_for_each_entry((p), &(k)->phdrs, node)
2040
2041 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
2042 {
2043         struct phdr_data *p = zalloc(sizeof(*p));
2044
2045         if (p) {
2046                 p->addr   = addr;
2047                 p->len    = len;
2048                 p->offset = offset;
2049         }
2050
2051         return p;
2052 }
2053
2054 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
2055                                                  u64 addr, u64 len,
2056                                                  off_t offset)
2057 {
2058         struct phdr_data *p = phdr_data__new(addr, len, offset);
2059
2060         if (p)
2061                 list_add_tail(&p->node, &kci->phdrs);
2062
2063         return p;
2064 }
2065
2066 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
2067 {
2068         struct phdr_data *p, *tmp;
2069
2070         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
2071                 list_del_init(&p->node);
2072                 free(p);
2073         }
2074 }
2075
2076 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
2077                                             u64 addr)
2078 {
2079         struct sym_data *s = zalloc(sizeof(*s));
2080
2081         if (s) {
2082                 s->addr = addr;
2083                 list_add_tail(&s->node, &kci->syms);
2084         }
2085
2086         return s;
2087 }
2088
2089 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
2090 {
2091         struct sym_data *s, *tmp;
2092
2093         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
2094                 list_del_init(&s->node);
2095                 free(s);
2096         }
2097 }
2098
2099 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
2100                                         u64 start)
2101 {
2102         struct kcore_copy_info *kci = arg;
2103
2104         if (!kallsyms__is_function(type))
2105                 return 0;
2106
2107         if (strchr(name, '[')) {
2108                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
2109                         kci->first_module_symbol = start;
2110                 if (start > kci->last_module_symbol)
2111                         kci->last_module_symbol = start;
2112                 return 0;
2113         }
2114
2115         if (!kci->first_symbol || start < kci->first_symbol)
2116                 kci->first_symbol = start;
2117
2118         if (!kci->last_symbol || start > kci->last_symbol)
2119                 kci->last_symbol = start;
2120
2121         if (!strcmp(name, "_stext")) {
2122                 kci->stext = start;
2123                 return 0;
2124         }
2125
2126         if (!strcmp(name, "_etext")) {
2127                 kci->etext = start;
2128                 return 0;
2129         }
2130
2131         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
2132                 return -1;
2133
2134         return 0;
2135 }
2136
2137 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
2138                                       const char *dir)
2139 {
2140         char kallsyms_filename[PATH_MAX];
2141
2142         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
2143
2144         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
2145                 return -1;
2146
2147         if (kallsyms__parse(kallsyms_filename, kci,
2148                             kcore_copy__process_kallsyms) < 0)
2149                 return -1;
2150
2151         return 0;
2152 }
2153
2154 static int kcore_copy__process_modules(void *arg,
2155                                        const char *name __maybe_unused,
2156                                        u64 start, u64 size __maybe_unused)
2157 {
2158         struct kcore_copy_info *kci = arg;
2159
2160         if (!kci->first_module || start < kci->first_module)
2161                 kci->first_module = start;
2162
2163         return 0;
2164 }
2165
2166 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
2167                                      const char *dir)
2168 {
2169         char modules_filename[PATH_MAX];
2170
2171         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
2172
2173         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
2174                 return -1;
2175
2176         if (modules__parse(modules_filename, kci,
2177                            kcore_copy__process_modules) < 0)
2178                 return -1;
2179
2180         return 0;
2181 }
2182
2183 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
2184                            u64 pgoff, u64 s, u64 e)
2185 {
2186         u64 len, offset;
2187
2188         if (s < start || s >= end)
2189                 return 0;
2190
2191         offset = (s - start) + pgoff;
2192         len = e < end ? e - s : end - s;
2193
2194         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
2195 }
2196
2197 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
2198 {
2199         struct kcore_copy_info *kci = data;
2200         u64 end = start + len;
2201         struct sym_data *sdat;
2202
2203         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
2204                 return -1;
2205
2206         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
2207                             kci->last_module_symbol))
2208                 return -1;
2209
2210         list_for_each_entry(sdat, &kci->syms, node) {
2211                 u64 s = round_down(sdat->addr, page_size);
2212
2213                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
2214                         return -1;
2215         }
2216
2217         return 0;
2218 }
2219
2220 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
2221 {
2222         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
2223                 return -1;
2224
2225         return 0;
2226 }
2227
2228 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
2229 {
2230         struct phdr_data *p, *k = NULL;
2231         u64 kend;
2232
2233         if (!kci->stext)
2234                 return;
2235
2236         /* Find phdr that corresponds to the kernel map (contains stext) */
2237         kcore_copy__for_each_phdr(kci, p) {
2238                 u64 pend = p->addr + p->len - 1;
2239
2240                 if (p->addr <= kci->stext && pend >= kci->stext) {
2241                         k = p;
2242                         break;
2243                 }
2244         }
2245
2246         if (!k)
2247                 return;
2248
2249         kend = k->offset + k->len;
2250
2251         /* Find phdrs that remap the kernel */
2252         kcore_copy__for_each_phdr(kci, p) {
2253                 u64 pend = p->offset + p->len;
2254
2255                 if (p == k)
2256                         continue;
2257
2258                 if (p->offset >= k->offset && pend <= kend)
2259                         p->remaps = k;
2260         }
2261 }
2262
2263 static void kcore_copy__layout(struct kcore_copy_info *kci)
2264 {
2265         struct phdr_data *p;
2266         off_t rel = 0;
2267
2268         kcore_copy__find_remaps(kci);
2269
2270         kcore_copy__for_each_phdr(kci, p) {
2271                 if (!p->remaps) {
2272                         p->rel = rel;
2273                         rel += p->len;
2274                 }
2275                 kci->phnum += 1;
2276         }
2277
2278         kcore_copy__for_each_phdr(kci, p) {
2279                 struct phdr_data *k = p->remaps;
2280
2281                 if (k)
2282                         p->rel = p->offset - k->offset + k->rel;
2283         }
2284 }
2285
2286 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
2287                                  Elf *elf)
2288 {
2289         if (kcore_copy__parse_kallsyms(kci, dir))
2290                 return -1;
2291
2292         if (kcore_copy__parse_modules(kci, dir))
2293                 return -1;
2294
2295         if (kci->stext)
2296                 kci->stext = round_down(kci->stext, page_size);
2297         else
2298                 kci->stext = round_down(kci->first_symbol, page_size);
2299
2300         if (kci->etext) {
2301                 kci->etext = round_up(kci->etext, page_size);
2302         } else if (kci->last_symbol) {
2303                 kci->etext = round_up(kci->last_symbol, page_size);
2304                 kci->etext += page_size;
2305         }
2306
2307         if (kci->first_module_symbol &&
2308             (!kci->first_module || kci->first_module_symbol < kci->first_module))
2309                 kci->first_module = kci->first_module_symbol;
2310
2311         kci->first_module = round_down(kci->first_module, page_size);
2312
2313         if (kci->last_module_symbol) {
2314                 kci->last_module_symbol = round_up(kci->last_module_symbol,
2315                                                    page_size);
2316                 kci->last_module_symbol += page_size;
2317         }
2318
2319         if (!kci->stext || !kci->etext)
2320                 return -1;
2321
2322         if (kci->first_module && !kci->last_module_symbol)
2323                 return -1;
2324
2325         if (kcore_copy__read_maps(kci, elf))
2326                 return -1;
2327
2328         kcore_copy__layout(kci);
2329
2330         return 0;
2331 }
2332
2333 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
2334                                  const char *name)
2335 {
2336         char from_filename[PATH_MAX];
2337         char to_filename[PATH_MAX];
2338
2339         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2340         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2341
2342         return copyfile_mode(from_filename, to_filename, 0400);
2343 }
2344
2345 static int kcore_copy__unlink(const char *dir, const char *name)
2346 {
2347         char filename[PATH_MAX];
2348
2349         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
2350
2351         return unlink(filename);
2352 }
2353
2354 static int kcore_copy__compare_fds(int from, int to)
2355 {
2356         char *buf_from;
2357         char *buf_to;
2358         ssize_t ret;
2359         size_t len;
2360         int err = -1;
2361
2362         buf_from = malloc(page_size);
2363         buf_to = malloc(page_size);
2364         if (!buf_from || !buf_to)
2365                 goto out;
2366
2367         while (1) {
2368                 /* Use read because mmap won't work on proc files */
2369                 ret = read(from, buf_from, page_size);
2370                 if (ret < 0)
2371                         goto out;
2372
2373                 if (!ret)
2374                         break;
2375
2376                 len = ret;
2377
2378                 if (readn(to, buf_to, len) != (int)len)
2379                         goto out;
2380
2381                 if (memcmp(buf_from, buf_to, len))
2382                         goto out;
2383         }
2384
2385         err = 0;
2386 out:
2387         free(buf_to);
2388         free(buf_from);
2389         return err;
2390 }
2391
2392 static int kcore_copy__compare_files(const char *from_filename,
2393                                      const char *to_filename)
2394 {
2395         int from, to, err = -1;
2396
2397         from = open(from_filename, O_RDONLY);
2398         if (from < 0)
2399                 return -1;
2400
2401         to = open(to_filename, O_RDONLY);
2402         if (to < 0)
2403                 goto out_close_from;
2404
2405         err = kcore_copy__compare_fds(from, to);
2406
2407         close(to);
2408 out_close_from:
2409         close(from);
2410         return err;
2411 }
2412
2413 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
2414                                     const char *name)
2415 {
2416         char from_filename[PATH_MAX];
2417         char to_filename[PATH_MAX];
2418
2419         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2420         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2421
2422         return kcore_copy__compare_files(from_filename, to_filename);
2423 }
2424
2425 /**
2426  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
2427  * @from_dir: from directory
2428  * @to_dir: to directory
2429  *
2430  * This function copies kallsyms, modules and kcore files from one directory to
2431  * another.  kallsyms and modules are copied entirely.  Only code segments are
2432  * copied from kcore.  It is assumed that two segments suffice: one for the
2433  * kernel proper and one for all the modules.  The code segments are determined
2434  * from kallsyms and modules files.  The kernel map starts at _stext or the
2435  * lowest function symbol, and ends at _etext or the highest function symbol.
2436  * The module map starts at the lowest module address and ends at the highest
2437  * module symbol.  Start addresses are rounded down to the nearest page.  End
2438  * addresses are rounded up to the nearest page.  An extra page is added to the
2439  * highest kernel symbol and highest module symbol to, hopefully, encompass that
2440  * symbol too.  Because it contains only code sections, the resulting kcore is
2441  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
2442  * is not the same for the kernel map and the modules map.  That happens because
2443  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
2444  * kallsyms file is compared with its copy to check that modules have not been
2445  * loaded or unloaded while the copies were taking place.
2446  *
2447  * Return: %0 on success, %-1 on failure.
2448  */
2449 int kcore_copy(const char *from_dir, const char *to_dir)
2450 {
2451         struct kcore kcore;
2452         struct kcore extract;
2453         int idx = 0, err = -1;
2454         off_t offset, sz;
2455         struct kcore_copy_info kci = { .stext = 0, };
2456         char kcore_filename[PATH_MAX];
2457         char extract_filename[PATH_MAX];
2458         struct phdr_data *p;
2459
2460         INIT_LIST_HEAD(&kci.phdrs);
2461         INIT_LIST_HEAD(&kci.syms);
2462
2463         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2464                 return -1;
2465
2466         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2467                 goto out_unlink_kallsyms;
2468
2469         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2470         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2471
2472         if (kcore__open(&kcore, kcore_filename))
2473                 goto out_unlink_modules;
2474
2475         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2476                 goto out_kcore_close;
2477
2478         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2479                 goto out_kcore_close;
2480
2481         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2482                 goto out_extract_close;
2483
2484         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2485                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2486         offset = round_up(offset, page_size);
2487
2488         kcore_copy__for_each_phdr(&kci, p) {
2489                 off_t offs = p->rel + offset;
2490
2491                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2492                         goto out_extract_close;
2493         }
2494
2495         sz = kcore__write(&extract);
2496         if (sz < 0 || sz > offset)
2497                 goto out_extract_close;
2498
2499         kcore_copy__for_each_phdr(&kci, p) {
2500                 off_t offs = p->rel + offset;
2501
2502                 if (p->remaps)
2503                         continue;
2504                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2505                         goto out_extract_close;
2506         }
2507
2508         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2509                 goto out_extract_close;
2510
2511         err = 0;
2512
2513 out_extract_close:
2514         kcore__close(&extract);
2515         if (err)
2516                 unlink(extract_filename);
2517 out_kcore_close:
2518         kcore__close(&kcore);
2519 out_unlink_modules:
2520         if (err)
2521                 kcore_copy__unlink(to_dir, "modules");
2522 out_unlink_kallsyms:
2523         if (err)
2524                 kcore_copy__unlink(to_dir, "kallsyms");
2525
2526         kcore_copy__free_phdrs(&kci);
2527         kcore_copy__free_syms(&kci);
2528
2529         return err;
2530 }
2531
2532 int kcore_extract__create(struct kcore_extract *kce)
2533 {
2534         struct kcore kcore;
2535         struct kcore extract;
2536         size_t count = 1;
2537         int idx = 0, err = -1;
2538         off_t offset = page_size, sz;
2539
2540         if (kcore__open(&kcore, kce->kcore_filename))
2541                 return -1;
2542
2543         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2544         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2545                 goto out_kcore_close;
2546
2547         if (kcore__copy_hdr(&kcore, &extract, count))
2548                 goto out_extract_close;
2549
2550         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2551                 goto out_extract_close;
2552
2553         sz = kcore__write(&extract);
2554         if (sz < 0 || sz > offset)
2555                 goto out_extract_close;
2556
2557         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2558                 goto out_extract_close;
2559
2560         err = 0;
2561
2562 out_extract_close:
2563         kcore__close(&extract);
2564         if (err)
2565                 unlink(kce->extract_filename);
2566 out_kcore_close:
2567         kcore__close(&kcore);
2568
2569         return err;
2570 }
2571
2572 void kcore_extract__delete(struct kcore_extract *kce)
2573 {
2574         unlink(kce->extract_filename);
2575 }
2576
2577 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2578
2579 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2580 {
2581         if (!base_off)
2582                 return;
2583
2584         if (tmp->bit32)
2585                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2586                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2587                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2588         else
2589                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2590                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2591                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2592 }
2593
2594 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2595                               GElf_Addr base_off)
2596 {
2597         if (!base_off)
2598                 return;
2599
2600         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2601                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2602         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2603                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2604 }
2605
2606 /**
2607  * populate_sdt_note : Parse raw data and identify SDT note
2608  * @elf: elf of the opened file
2609  * @data: raw data of a section with description offset applied
2610  * @len: note description size
2611  * @type: type of the note
2612  * @sdt_notes: List to add the SDT note
2613  *
2614  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2615  * if its an SDT note, it appends to @sdt_notes list.
2616  */
2617 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2618                              struct list_head *sdt_notes)
2619 {
2620         const char *provider, *name, *args;
2621         struct sdt_note *tmp = NULL;
2622         GElf_Ehdr ehdr;
2623         GElf_Shdr shdr;
2624         int ret = -EINVAL;
2625
2626         union {
2627                 Elf64_Addr a64[NR_ADDR];
2628                 Elf32_Addr a32[NR_ADDR];
2629         } buf;
2630
2631         Elf_Data dst = {
2632                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2633                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2634                 .d_off = 0, .d_align = 0
2635         };
2636         Elf_Data src = {
2637                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2638                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2639                 .d_align = 0
2640         };
2641
2642         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2643         if (!tmp) {
2644                 ret = -ENOMEM;
2645                 goto out_err;
2646         }
2647
2648         INIT_LIST_HEAD(&tmp->note_list);
2649
2650         if (len < dst.d_size + 3)
2651                 goto out_free_note;
2652
2653         /* Translation from file representation to memory representation */
2654         if (gelf_xlatetom(*elf, &dst, &src,
2655                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2656                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2657                 goto out_free_note;
2658         }
2659
2660         /* Populate the fields of sdt_note */
2661         provider = data + dst.d_size;
2662
2663         name = (const char *)memchr(provider, '\0', data + len - provider);
2664         if (name++ == NULL)
2665                 goto out_free_note;
2666
2667         tmp->provider = strdup(provider);
2668         if (!tmp->provider) {
2669                 ret = -ENOMEM;
2670                 goto out_free_note;
2671         }
2672         tmp->name = strdup(name);
2673         if (!tmp->name) {
2674                 ret = -ENOMEM;
2675                 goto out_free_prov;
2676         }
2677
2678         args = memchr(name, '\0', data + len - name);
2679
2680         /*
2681          * There is no argument if:
2682          * - We reached the end of the note;
2683          * - There is not enough room to hold a potential string;
2684          * - The argument string is empty or just contains ':'.
2685          */
2686         if (args == NULL || data + len - args < 2 ||
2687                 args[1] == ':' || args[1] == '\0')
2688                 tmp->args = NULL;
2689         else {
2690                 tmp->args = strdup(++args);
2691                 if (!tmp->args) {
2692                         ret = -ENOMEM;
2693                         goto out_free_name;
2694                 }
2695         }
2696
2697         if (gelf_getclass(*elf) == ELFCLASS32) {
2698                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2699                 tmp->bit32 = true;
2700         } else {
2701                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2702                 tmp->bit32 = false;
2703         }
2704
2705         if (!gelf_getehdr(*elf, &ehdr)) {
2706                 pr_debug("%s : cannot get elf header.\n", __func__);
2707                 ret = -EBADF;
2708                 goto out_free_args;
2709         }
2710
2711         /* Adjust the prelink effect :
2712          * Find out the .stapsdt.base section.
2713          * This scn will help us to handle prelinking (if present).
2714          * Compare the retrieved file offset of the base section with the
2715          * base address in the description of the SDT note. If its different,
2716          * then accordingly, adjust the note location.
2717          */
2718         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2719                 sdt_adjust_loc(tmp, shdr.sh_offset);
2720
2721         /* Adjust reference counter offset */
2722         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2723                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2724
2725         list_add_tail(&tmp->note_list, sdt_notes);
2726         return 0;
2727
2728 out_free_args:
2729         zfree(&tmp->args);
2730 out_free_name:
2731         zfree(&tmp->name);
2732 out_free_prov:
2733         zfree(&tmp->provider);
2734 out_free_note:
2735         free(tmp);
2736 out_err:
2737         return ret;
2738 }
2739
2740 /**
2741  * construct_sdt_notes_list : constructs a list of SDT notes
2742  * @elf : elf to look into
2743  * @sdt_notes : empty list_head
2744  *
2745  * Scans the sections in 'elf' for the section
2746  * .note.stapsdt. It, then calls populate_sdt_note to find
2747  * out the SDT events and populates the 'sdt_notes'.
2748  */
2749 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2750 {
2751         GElf_Ehdr ehdr;
2752         Elf_Scn *scn = NULL;
2753         Elf_Data *data;
2754         GElf_Shdr shdr;
2755         size_t shstrndx, next;
2756         GElf_Nhdr nhdr;
2757         size_t name_off, desc_off, offset;
2758         int ret = 0;
2759
2760         if (gelf_getehdr(elf, &ehdr) == NULL) {
2761                 ret = -EBADF;
2762                 goto out_ret;
2763         }
2764         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2765                 ret = -EBADF;
2766                 goto out_ret;
2767         }
2768
2769         /* Look for the required section */
2770         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2771         if (!scn) {
2772                 ret = -ENOENT;
2773                 goto out_ret;
2774         }
2775
2776         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2777                 ret = -ENOENT;
2778                 goto out_ret;
2779         }
2780
2781         data = elf_getdata(scn, NULL);
2782
2783         /* Get the SDT notes */
2784         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2785                                               &desc_off)) > 0; offset = next) {
2786                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2787                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2788                             sizeof(SDT_NOTE_NAME))) {
2789                         /* Check the type of the note */
2790                         if (nhdr.n_type != SDT_NOTE_TYPE)
2791                                 goto out_ret;
2792
2793                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2794                                                 nhdr.n_descsz, sdt_notes);
2795                         if (ret < 0)
2796                                 goto out_ret;
2797                 }
2798         }
2799         if (list_empty(sdt_notes))
2800                 ret = -ENOENT;
2801
2802 out_ret:
2803         return ret;
2804 }
2805
2806 /**
2807  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2808  * @head : empty list_head
2809  * @target : file to find SDT notes from
2810  *
2811  * This opens the file, initializes
2812  * the ELF and then calls construct_sdt_notes_list.
2813  */
2814 int get_sdt_note_list(struct list_head *head, const char *target)
2815 {
2816         Elf *elf;
2817         int fd, ret;
2818
2819         fd = open(target, O_RDONLY);
2820         if (fd < 0)
2821                 return -EBADF;
2822
2823         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2824         if (!elf) {
2825                 ret = -EBADF;
2826                 goto out_close;
2827         }
2828         ret = construct_sdt_notes_list(elf, head);
2829         elf_end(elf);
2830 out_close:
2831         close(fd);
2832         return ret;
2833 }
2834
2835 /**
2836  * cleanup_sdt_note_list : free the sdt notes' list
2837  * @sdt_notes: sdt notes' list
2838  *
2839  * Free up the SDT notes in @sdt_notes.
2840  * Returns the number of SDT notes free'd.
2841  */
2842 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2843 {
2844         struct sdt_note *tmp, *pos;
2845         int nr_free = 0;
2846
2847         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2848                 list_del_init(&pos->note_list);
2849                 zfree(&pos->args);
2850                 zfree(&pos->name);
2851                 zfree(&pos->provider);
2852                 free(pos);
2853                 nr_free++;
2854         }
2855         return nr_free;
2856 }
2857
2858 /**
2859  * sdt_notes__get_count: Counts the number of sdt events
2860  * @start: list_head to sdt_notes list
2861  *
2862  * Returns the number of SDT notes in a list
2863  */
2864 int sdt_notes__get_count(struct list_head *start)
2865 {
2866         struct sdt_note *sdt_ptr;
2867         int count = 0;
2868
2869         list_for_each_entry(sdt_ptr, start, note_list)
2870                 count++;
2871         return count;
2872 }
2873 #endif
2874
2875 void symbol__elf_init(void)
2876 {
2877         elf_version(EV_CURRENT);
2878 }