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-ocaml.h"
  16 #include "demangle-java.h"
  17 #include "demangle-rust.h"
  18 #include "machine.h"
  19 #include "vdso.h"
  20 #include "debug.h"
  21 #include "util/copyfile.h"
  22 #include <linux/ctype.h>
  23 #include <linux/kernel.h>
  24 #include <linux/zalloc.h>
  25 #include <symbol/kallsyms.h>
  26 #include <internal/lib.h>
  27
  28 #ifndef EM_AARCH64
  29 #define EM_AARCH64      183  /* ARM 64 bit */
  30 #endif
  31
  32 #ifndef ELF32_ST_VISIBILITY
  33 #define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  34 #endif
  35
  36 /* For ELF64 the definitions are the same.  */
  37 #ifndef ELF64_ST_VISIBILITY
  38 #define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  39 #endif
  40
  41 /* How to extract information held in the st_other field.  */
  42 #ifndef GELF_ST_VISIBILITY
  43 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  44 #endif
  45
  46 typedef Elf64_Nhdr GElf_Nhdr;
  47
  48 #ifndef DMGL_PARAMS
  49 #define DMGL_NO_OPTS     0              /* For readability... */
  50 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
  51 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  52 #endif
  53
  54 #ifdef HAVE_LIBBFD_SUPPORT
  55 #define PACKAGE 'perf'
  56 #include <bfd.h>
  57 #else
  58 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  59 extern char *cplus_demangle(const char *, int);
  60
  61 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  62 {
  63         return cplus_demangle(c, i);
  64 }
  65 #else
  66 #ifdef NO_DEMANGLE
  67 static inline char *bfd_demangle(void __maybe_unused *v,
  68                                  const char __maybe_unused *c,
  69                                  int __maybe_unused i)
  70 {
  71         return NULL;
  72 }
  73 #endif
  74 #endif
  75 #endif
  76
  77 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  78 static int elf_getphdrnum(Elf *elf, size_t *dst)
  79 {
  80         GElf_Ehdr gehdr;
  81         GElf_Ehdr *ehdr;
  82
  83         ehdr = gelf_getehdr(elf, &gehdr);
  84         if (!ehdr)
  85                 return -1;
  86
  87         *dst = ehdr->e_phnum;
  88
  89         return 0;
  90 }
  91 #endif
  92
  93 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  94 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  95 {
  96         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  97         return -1;
  98 }
  99 #endif
 100
 101 #ifndef NT_GNU_BUILD_ID
 102 #define NT_GNU_BUILD_ID 3
 103 #endif
 104
 105 /**
 106  * elf_symtab__for_each_symbol - iterate thru all the symbols
 107  *
 108  * @syms: struct elf_symtab instance to iterate
 109  * @idx: uint32_t idx
 110  * @sym: GElf_Sym iterator
 111  */
 112 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 113         for (idx = 0, gelf_getsym(syms, idx, &sym);\
 114              idx < nr_syms; \
 115              idx++, gelf_getsym(syms, idx, &sym))
 116
 117 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 118 {
 119         return GELF_ST_TYPE(sym->st_info);
 120 }
 121
 122 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 123 {
 124         return GELF_ST_VISIBILITY(sym->st_other);
 125 }
 126
 127 #ifndef STT_GNU_IFUNC
 128 #define STT_GNU_IFUNC 10
 129 #endif
 130
 131 static inline int elf_sym__is_function(const GElf_Sym *sym)
 132 {
 133         return (elf_sym__type(sym) == STT_FUNC ||
 134                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 135                sym->st_name != 0 &&
 136                sym->st_shndx != SHN_UNDEF;
 137 }
 138
 139 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 140 {
 141         return elf_sym__type(sym) == STT_OBJECT &&
 142                 sym->st_name != 0 &&
 143                 sym->st_shndx != SHN_UNDEF;
 144 }
 145
 146 static inline int elf_sym__is_label(const GElf_Sym *sym)
 147 {
 148         return elf_sym__type(sym) == STT_NOTYPE &&
 149                 sym->st_name != 0 &&
 150                 sym->st_shndx != SHN_UNDEF &&
 151                 sym->st_shndx != SHN_ABS &&
 152                 elf_sym__visibility(sym) != STV_HIDDEN &&
 153                 elf_sym__visibility(sym) != STV_INTERNAL;
 154 }
 155
 156 static bool elf_sym__filter(GElf_Sym *sym)
 157 {
 158         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 159 }
 160
 161 static inline const char *elf_sym__name(const GElf_Sym *sym,
 162                                         const Elf_Data *symstrs)
 163 {
 164         return symstrs->d_buf + sym->st_name;
 165 }
 166
 167 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 168                                         const Elf_Data *secstrs)
 169 {
 170         return secstrs->d_buf + shdr->sh_name;
 171 }
 172
 173 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 174                                         const Elf_Data *secstrs)
 175 {
 176         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 177 }
 178
 179 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 180                                     const Elf_Data *secstrs)
 181 {
 182         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 183 }
 184
 185 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 186 {
 187         return elf_sec__is_text(shdr, secstrs) ||
 188                elf_sec__is_data(shdr, secstrs);
 189 }
 190
 191 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 192 {
 193         Elf_Scn *sec = NULL;
 194         GElf_Shdr shdr;
 195         size_t cnt = 1;
 196
 197         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 198                 gelf_getshdr(sec, &shdr);
 199
 200                 if ((addr >= shdr.sh_addr) &&
 201                     (addr < (shdr.sh_addr + shdr.sh_size)))
 202                         return cnt;
 203
 204                 ++cnt;
 205         }
 206
 207         return -1;
 208 }
 209
 210 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 211                              GElf_Shdr *shp, const char *name, size_t *idx)
 212 {
 213         Elf_Scn *sec = NULL;
 214         size_t cnt = 1;
 215
 216         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 217         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 218                 return NULL;
 219
 220         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 221                 char *str;
 222
 223                 gelf_getshdr(sec, shp);
 224                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 225                 if (str && !strcmp(name, str)) {
 226                         if (idx)
 227                                 *idx = cnt;
 228                         return sec;
 229                 }
 230                 ++cnt;
 231         }
 232
 233         return NULL;
 234 }
 235
 236 bool filename__has_section(const char *filename, const char *sec)
 237 {
 238         int fd;
 239         Elf *elf;
 240         GElf_Ehdr ehdr;
 241         GElf_Shdr shdr;
 242         bool found = false;
 243
 244         fd = open(filename, O_RDONLY);
 245         if (fd < 0)
 246                 return false;
 247
 248         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 249         if (elf == NULL)
 250                 goto out;
 251
 252         if (gelf_getehdr(elf, &ehdr) == NULL)
 253                 goto elf_out;
 254
 255         found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL);
 256
 257 elf_out:
 258         elf_end(elf);
 259 out:
 260         close(fd);
 261         return found;
 262 }
 263
 264 static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr)
 265 {
 266         size_t i, phdrnum;
 267         u64 sz;
 268
 269         if (elf_getphdrnum(elf, &phdrnum))
 270                 return -1;
 271
 272         for (i = 0; i < phdrnum; i++) {
 273                 if (gelf_getphdr(elf, i, phdr) == NULL)
 274                         return -1;
 275
 276                 if (phdr->p_type != PT_LOAD)
 277                         continue;
 278
 279                 sz = max(phdr->p_memsz, phdr->p_filesz);
 280                 if (!sz)
 281                         continue;
 282
 283                 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz))
 284                         return 0;
 285         }
 286
 287         /* Not found any valid program header */
 288         return -1;
 289 }
 290
 291 static bool want_demangle(bool is_kernel_sym)
 292 {
 293         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 294 }
 295
 296 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 297 {
 298         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 299         char *demangled = NULL;
 300
 301         /*
 302          * We need to figure out if the object was created from C++ sources
 303          * DWARF DW_compile_unit has this, but we don't always have access
 304          * to it...
 305          */
 306         if (!want_demangle(dso->kernel || kmodule))
 307             return demangled;
 308
 309         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 310         if (demangled == NULL) {
 311                 demangled = ocaml_demangle_sym(elf_name);
 312                 if (demangled == NULL) {
 313                         demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 314                 }
 315         }
 316         else if (rust_is_mangled(demangled))
 317                 /*
 318                     * Input to Rust demangling is the BFD-demangled
 319                     * name which it Rust-demangles in place.
 320                     */
 321                 rust_demangle_sym(demangled);
 322
 323         return demangled;
 324 }
 325
 326 struct rel_info {
 327         u32             nr_entries;
 328         u32             *sorted;
 329         bool            is_rela;
 330         Elf_Data        *reldata;
 331         GElf_Rela       rela;
 332         GElf_Rel        rel;
 333 };
 334
 335 static u32 get_rel_symidx(struct rel_info *ri, u32 idx)
 336 {
 337         idx = ri->sorted ? ri->sorted[idx] : idx;
 338         if (ri->is_rela) {
 339                 gelf_getrela(ri->reldata, idx, &ri->rela);
 340                 return GELF_R_SYM(ri->rela.r_info);
 341         }
 342         gelf_getrel(ri->reldata, idx, &ri->rel);
 343         return GELF_R_SYM(ri->rel.r_info);
 344 }
 345
 346 static u64 get_rel_offset(struct rel_info *ri, u32 x)
 347 {
 348         if (ri->is_rela) {
 349                 GElf_Rela rela;
 350
 351                 gelf_getrela(ri->reldata, x, &rela);
 352                 return rela.r_offset;
 353         } else {
 354                 GElf_Rel rel;
 355
 356                 gelf_getrel(ri->reldata, x, &rel);
 357                 return rel.r_offset;
 358         }
 359 }
 360
 361 static int rel_cmp(const void *a, const void *b, void *r)
 362 {
 363         struct rel_info *ri = r;
 364         u64 a_offset = get_rel_offset(ri, *(const u32 *)a);
 365         u64 b_offset = get_rel_offset(ri, *(const u32 *)b);
 366
 367         return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0);
 368 }
 369
 370 static int sort_rel(struct rel_info *ri)
 371 {
 372         size_t sz = sizeof(ri->sorted[0]);
 373         u32 i;
 374
 375         ri->sorted = calloc(ri->nr_entries, sz);
 376         if (!ri->sorted)
 377                 return -1;
 378         for (i = 0; i < ri->nr_entries; i++)
 379                 ri->sorted[i] = i;
 380         qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri);
 381         return 0;
 382 }
 383
 384 /*
 385  * For x86_64, the GNU linker is putting IFUNC information in the relocation
 386  * addend.
 387  */
 388 static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri)
 389 {
 390         return ehdr->e_machine == EM_X86_64 && ri->is_rela &&
 391                GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE;
 392 }
 393
 394 static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr,
 395                            struct rel_info *ri, char *buf, size_t buf_sz)
 396 {
 397         u64 addr = ri->rela.r_addend;
 398         struct symbol *sym;
 399         GElf_Phdr phdr;
 400
 401         if (!addend_may_be_ifunc(ehdr, ri))
 402                 return false;
 403
 404         if (elf_read_program_header(elf, addr, &phdr))
 405                 return false;
 406
 407         addr -= phdr.p_vaddr - phdr.p_offset;
 408
 409         sym = dso__find_symbol_nocache(dso, addr);
 410
 411         /* Expecting the address to be an IFUNC or IFUNC alias */
 412         if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias))
 413                 return false;
 414
 415         snprintf(buf, buf_sz, "%s@plt", sym->name);
 416
 417         return true;
 418 }
 419
 420 static void exit_rel(struct rel_info *ri)
 421 {
 422         free(ri->sorted);
 423 }
 424
 425 static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
 426                           u64 *plt_header_size, u64 *plt_entry_size)
 427 {
 428         switch (ehdr->e_machine) {
 429         case EM_ARM:
 430                 *plt_header_size = 20;
 431                 *plt_entry_size = 12;
 432                 return true;
 433         case EM_AARCH64:
 434                 *plt_header_size = 32;
 435                 *plt_entry_size = 16;
 436                 return true;
 437         case EM_SPARC:
 438                 *plt_header_size = 48;
 439                 *plt_entry_size = 12;
 440                 return true;
 441         case EM_SPARCV9:
 442                 *plt_header_size = 128;
 443                 *plt_entry_size = 32;
 444                 return true;
 445         case EM_386:
 446         case EM_X86_64:
 447                 *plt_entry_size = shdr_plt->sh_entsize;
 448                 /* Size is 8 or 16, if not, assume alignment indicates size */
 449                 if (*plt_entry_size != 8 && *plt_entry_size != 16)
 450                         *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16;
 451                 *plt_header_size = *plt_entry_size;
 452                 break;
 453         default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 454                 *plt_header_size = shdr_plt->sh_entsize;
 455                 *plt_entry_size = shdr_plt->sh_entsize;
 456                 break;
 457         }
 458         if (*plt_entry_size)
 459                 return true;
 460         pr_debug("Missing PLT entry size for %s\n", dso->long_name);
 461         return false;
 462 }
 463
 464 static bool machine_is_x86(GElf_Half e_machine)
 465 {
 466         return e_machine == EM_386 || e_machine == EM_X86_64;
 467 }
 468
 469 struct rela_dyn {
 470         GElf_Addr       offset;
 471         u32             sym_idx;
 472 };
 473
 474 struct rela_dyn_info {
 475         struct dso      *dso;
 476         Elf_Data        *plt_got_data;
 477         u32             nr_entries;
 478         struct rela_dyn *sorted;
 479         Elf_Data        *dynsym_data;
 480         Elf_Data        *dynstr_data;
 481         Elf_Data        *rela_dyn_data;
 482 };
 483
 484 static void exit_rela_dyn(struct rela_dyn_info *di)
 485 {
 486         free(di->sorted);
 487 }
 488
 489 static int cmp_offset(const void *a, const void *b)
 490 {
 491         const struct rela_dyn *va = a;
 492         const struct rela_dyn *vb = b;
 493
 494         return va->offset < vb->offset ? -1 : (va->offset > vb->offset ? 1 : 0);
 495 }
 496
 497 static int sort_rela_dyn(struct rela_dyn_info *di)
 498 {
 499         u32 i, n;
 500
 501         di->sorted = calloc(di->nr_entries, sizeof(di->sorted[0]));
 502         if (!di->sorted)
 503                 return -1;
 504
 505         /* Get data for sorting: the offset and symbol index */
 506         for (i = 0, n = 0; i < di->nr_entries; i++) {
 507                 GElf_Rela rela;
 508                 u32 sym_idx;
 509
 510                 gelf_getrela(di->rela_dyn_data, i, &rela);
 511                 sym_idx = GELF_R_SYM(rela.r_info);
 512                 if (sym_idx) {
 513                         di->sorted[n].sym_idx = sym_idx;
 514                         di->sorted[n].offset = rela.r_offset;
 515                         n += 1;
 516                 }
 517         }
 518
 519         /* Sort by offset */
 520         di->nr_entries = n;
 521         qsort(di->sorted, n, sizeof(di->sorted[0]), cmp_offset);
 522
 523         return 0;
 524 }
 525
 526 static void get_rela_dyn_info(Elf *elf, GElf_Ehdr *ehdr, struct rela_dyn_info *di, Elf_Scn *scn)
 527 {
 528         GElf_Shdr rela_dyn_shdr;
 529         GElf_Shdr shdr;
 530
 531         di->plt_got_data = elf_getdata(scn, NULL);
 532
 533         scn = elf_section_by_name(elf, ehdr, &rela_dyn_shdr, ".rela.dyn", NULL);
 534         if (!scn || !rela_dyn_shdr.sh_link || !rela_dyn_shdr.sh_entsize)
 535                 return;
 536
 537         di->nr_entries = rela_dyn_shdr.sh_size / rela_dyn_shdr.sh_entsize;
 538         di->rela_dyn_data = elf_getdata(scn, NULL);
 539
 540         scn = elf_getscn(elf, rela_dyn_shdr.sh_link);
 541         if (!scn || !gelf_getshdr(scn, &shdr) || !shdr.sh_link)
 542                 return;
 543
 544         di->dynsym_data = elf_getdata(scn, NULL);
 545         di->dynstr_data = elf_getdata(elf_getscn(elf, shdr.sh_link), NULL);
 546
 547         if (!di->plt_got_data || !di->dynstr_data || !di->dynsym_data || !di->rela_dyn_data)
 548                 return;
 549
 550         /* Sort into offset order */
 551         sort_rela_dyn(di);
 552 }
 553
 554 /* Get instruction displacement from a plt entry for x86_64 */
 555 static u32 get_x86_64_plt_disp(const u8 *p)
 556 {
 557         u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa};
 558         int n = 0;
 559
 560         /* Skip endbr64 */
 561         if (!memcmp(p, endbr64, sizeof(endbr64)))
 562                 n += sizeof(endbr64);
 563         /* Skip bnd prefix */
 564         if (p[n] == 0xf2)
 565                 n += 1;
 566         /* jmp with 4-byte displacement */
 567         if (p[n] == 0xff && p[n + 1] == 0x25) {
 568                 n += 2;
 569                 /* Also add offset from start of entry to end of instruction */
 570                 return n + 4 + le32toh(*(const u32 *)(p + n));
 571         }
 572         return 0;
 573 }
 574
 575 static bool get_plt_got_name(GElf_Shdr *shdr, size_t i,
 576                              struct rela_dyn_info *di,
 577                              char *buf, size_t buf_sz)
 578 {
 579         struct rela_dyn vi, *vr;
 580         const char *sym_name;
 581         char *demangled;
 582         GElf_Sym sym;
 583         u32 disp;
 584
 585         if (!di->sorted)
 586                 return false;
 587
 588         disp = get_x86_64_plt_disp(di->plt_got_data->d_buf + i);
 589         if (!disp)
 590                 return false;
 591
 592         /* Compute target offset of the .plt.got entry */
 593         vi.offset = shdr->sh_offset + di->plt_got_data->d_off + i + disp;
 594
 595         /* Find that offset in .rela.dyn (sorted by offset) */
 596         vr = bsearch(&vi, di->sorted, di->nr_entries, sizeof(di->sorted[0]), cmp_offset);
 597         if (!vr)
 598                 return false;
 599
 600         /* Get the associated symbol */
 601         gelf_getsym(di->dynsym_data, vr->sym_idx, &sym);
 602         sym_name = elf_sym__name(&sym, di->dynstr_data);
 603         demangled = demangle_sym(di->dso, 0, sym_name);
 604         if (demangled != NULL)
 605                 sym_name = demangled;
 606
 607         snprintf(buf, buf_sz, "%s@plt", sym_name);
 608
 609         free(demangled);
 610
 611         return *sym_name;
 612 }
 613
 614 static int dso__synthesize_plt_got_symbols(struct dso *dso, Elf *elf,
 615                                            GElf_Ehdr *ehdr,
 616                                            char *buf, size_t buf_sz)
 617 {
 618         struct rela_dyn_info di = { .dso = dso };
 619         struct symbol *sym;
 620         GElf_Shdr shdr;
 621         Elf_Scn *scn;
 622         int err = -1;
 623         size_t i;
 624
 625         scn = elf_section_by_name(elf, ehdr, &shdr, ".plt.got", NULL);
 626         if (!scn || !shdr.sh_entsize)
 627                 return 0;
 628
 629         if (ehdr->e_machine == EM_X86_64)
 630                 get_rela_dyn_info(elf, ehdr, &di, scn);
 631
 632         for (i = 0; i < shdr.sh_size; i += shdr.sh_entsize) {
 633                 if (!get_plt_got_name(&shdr, i, &di, buf, buf_sz))
 634                         snprintf(buf, buf_sz, "offset_%#" PRIx64 "@plt", (u64)shdr.sh_offset + i);
 635                 sym = symbol__new(shdr.sh_offset + i, shdr.sh_entsize, STB_GLOBAL, STT_FUNC, buf);
 636                 if (!sym)
 637                         goto out;
 638                 symbols__insert(&dso->symbols, sym);
 639         }
 640         err = 0;
 641 out:
 642         exit_rela_dyn(&di);
 643         return err;
 644 }
 645
 646 /*
 647  * We need to check if we have a .dynsym, so that we can handle the
 648  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 649  * .dynsym or .symtab).
 650  * And always look at the original dso, not at debuginfo packages, that
 651  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 652  */
 653 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 654 {
 655         uint32_t idx;
 656         GElf_Sym sym;
 657         u64 plt_offset, plt_header_size, plt_entry_size;
 658         GElf_Shdr shdr_plt, plt_sec_shdr;
 659         struct symbol *f, *plt_sym;
 660         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 661         Elf_Data *syms, *symstrs;
 662         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 663         GElf_Ehdr ehdr;
 664         char sympltname[1024];
 665         Elf *elf;
 666         int nr = 0, err = -1;
 667         struct rel_info ri = { .is_rela = false };
 668         bool lazy_plt;
 669
 670         elf = ss->elf;
 671         ehdr = ss->ehdr;
 672
 673         if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL))
 674                 return 0;
 675
 676         /*
 677          * A symbol from a previous section (e.g. .init) can have been expanded
 678          * by symbols__fixup_end() to overlap .plt. Truncate it before adding
 679          * a symbol for .plt header.
 680          */
 681         f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset);
 682         if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset)
 683                 f->end = shdr_plt.sh_offset;
 684
 685         if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size))
 686                 return 0;
 687
 688         /* Add a symbol for .plt header */
 689         plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt");
 690         if (!plt_sym)
 691                 goto out_elf_end;
 692         symbols__insert(&dso->symbols, plt_sym);
 693
 694         /* Only x86 has .plt.got */
 695         if (machine_is_x86(ehdr.e_machine) &&
 696             dso__synthesize_plt_got_symbols(dso, elf, &ehdr, sympltname, sizeof(sympltname)))
 697                 goto out_elf_end;
 698
 699         /* Only x86 has .plt.sec */
 700         if (machine_is_x86(ehdr.e_machine) &&
 701             elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) {
 702                 if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size))
 703                         return 0;
 704                 /* Extend .plt symbol to entire .plt */
 705                 plt_sym->end = plt_sym->start + shdr_plt.sh_size;
 706                 /* Use .plt.sec offset */
 707                 plt_offset = plt_sec_shdr.sh_offset;
 708                 lazy_plt = false;
 709         } else {
 710                 plt_offset = shdr_plt.sh_offset;
 711                 lazy_plt = true;
 712         }
 713
 714         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 715                                           ".rela.plt", NULL);
 716         if (scn_plt_rel == NULL) {
 717                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 718                                                   ".rel.plt", NULL);
 719                 if (scn_plt_rel == NULL)
 720                         return 0;
 721         }
 722
 723         if (shdr_rel_plt.sh_type != SHT_RELA &&
 724             shdr_rel_plt.sh_type != SHT_REL)
 725                 return 0;
 726
 727         if (!shdr_rel_plt.sh_link)
 728                 return 0;
 729
 730         if (shdr_rel_plt.sh_link == ss->dynsym_idx) {
 731                 scn_dynsym = ss->dynsym;
 732                 shdr_dynsym = ss->dynshdr;
 733         } else if (shdr_rel_plt.sh_link == ss->symtab_idx) {
 734                 /*
 735                  * A static executable can have a .plt due to IFUNCs, in which
 736                  * case .symtab is used not .dynsym.
 737                  */
 738                 scn_dynsym = ss->symtab;
 739                 shdr_dynsym = ss->symshdr;
 740         } else {
 741                 goto out_elf_end;
 742         }
 743
 744         if (!scn_dynsym)
 745                 return 0;
 746
 747         /*
 748          * Fetch the relocation section to find the idxes to the GOT
 749          * and the symbols in the .dynsym they refer to.
 750          */
 751         ri.reldata = elf_getdata(scn_plt_rel, NULL);
 752         if (!ri.reldata)
 753                 goto out_elf_end;
 754
 755         syms = elf_getdata(scn_dynsym, NULL);
 756         if (syms == NULL)
 757                 goto out_elf_end;
 758
 759         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 760         if (scn_symstrs == NULL)
 761                 goto out_elf_end;
 762
 763         symstrs = elf_getdata(scn_symstrs, NULL);
 764         if (symstrs == NULL)
 765                 goto out_elf_end;
 766
 767         if (symstrs->d_size == 0)
 768                 goto out_elf_end;
 769
 770         ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 771
 772         ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;
 773
 774         if (lazy_plt) {
 775                 /*
 776                  * Assume a .plt with the same number of entries as the number
 777                  * of relocation entries is not lazy and does not have a header.
 778                  */
 779                 if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size)
 780                         dso__delete_symbol(dso, plt_sym);
 781                 else
 782                         plt_offset += plt_header_size;
 783         }
 784
 785         /*
 786          * x86 doesn't insert IFUNC relocations in .plt order, so sort to get
 787          * back in order.
 788          */
 789         if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri))
 790                 goto out_elf_end;
 791
 792         for (idx = 0; idx < ri.nr_entries; idx++) {
 793                 const char *elf_name = NULL;
 794                 char *demangled = NULL;
 795
 796                 gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym);
 797
 798                 elf_name = elf_sym__name(&sym, symstrs);
 799                 demangled = demangle_sym(dso, 0, elf_name);
 800                 if (demangled)
 801                         elf_name = demangled;
 802                 if (*elf_name)
 803                         snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name);
 804                 else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname)))
 805                         snprintf(sympltname, sizeof(sympltname),
 806                                  "offset_%#" PRIx64 "@plt", plt_offset);
 807                 free(demangled);
 808
 809                 f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname);
 810                 if (!f)
 811                         goto out_elf_end;
 812
 813                 plt_offset += plt_entry_size;
 814                 symbols__insert(&dso->symbols, f);
 815                 ++nr;
 816         }
 817
 818         err = 0;
 819 out_elf_end:
 820         exit_rel(&ri);
 821         if (err == 0)
 822                 return nr;
 823         pr_debug("%s: problems reading %s PLT info.\n",
 824                  __func__, dso->long_name);
 825         return 0;
 826 }
 827
 828 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 829 {
 830         return demangle_sym(dso, kmodule, elf_name);
 831 }
 832
 833 /*
 834  * Align offset to 4 bytes as needed for note name and descriptor data.
 835  */
 836 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 837
 838 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 839 {
 840         int err = -1;
 841         GElf_Ehdr ehdr;
 842         GElf_Shdr shdr;
 843         Elf_Data *data;
 844         Elf_Scn *sec;
 845         Elf_Kind ek;
 846         void *ptr;
 847
 848         if (size < BUILD_ID_SIZE)
 849                 goto out;
 850
 851         ek = elf_kind(elf);
 852         if (ek != ELF_K_ELF)
 853                 goto out;
 854
 855         if (gelf_getehdr(elf, &ehdr) == NULL) {
 856                 pr_err("%s: cannot get elf header.\n", __func__);
 857                 goto out;
 858         }
 859
 860         /*
 861          * Check following sections for notes:
 862          *   '.note.gnu.build-id'
 863          *   '.notes'
 864          *   '.note' (VDSO specific)
 865          */
 866         do {
 867                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 868                                           ".note.gnu.build-id", NULL);
 869                 if (sec)
 870                         break;
 871
 872                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 873                                           ".notes", NULL);
 874                 if (sec)
 875                         break;
 876
 877                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 878                                           ".note", NULL);
 879                 if (sec)
 880                         break;
 881
 882                 return err;
 883
 884         } while (0);
 885
 886         data = elf_getdata(sec, NULL);
 887         if (data == NULL)
 888                 goto out;
 889
 890         ptr = data->d_buf;
 891         while (ptr < (data->d_buf + data->d_size)) {
 892                 GElf_Nhdr *nhdr = ptr;
 893                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 894                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 895                 const char *name;
 896
 897                 ptr += sizeof(*nhdr);
 898                 name = ptr;
 899                 ptr += namesz;
 900                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 901                     nhdr->n_namesz == sizeof("GNU")) {
 902                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 903                                 size_t sz = min(size, descsz);
 904                                 memcpy(bf, ptr, sz);
 905                                 memset(bf + sz, 0, size - sz);
 906                                 err = descsz;
 907                                 break;
 908                         }
 909                 }
 910                 ptr += descsz;
 911         }
 912
 913 out:
 914         return err;
 915 }
 916
 917 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT
 918
 919 static int read_build_id(const char *filename, struct build_id *bid)
 920 {
 921         size_t size = sizeof(bid->data);
 922         int err = -1;
 923         bfd *abfd;
 924
 925         abfd = bfd_openr(filename, NULL);
 926         if (!abfd)
 927                 return -1;
 928
 929         if (!bfd_check_format(abfd, bfd_object)) {
 930                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 931                 goto out_close;
 932         }
 933
 934         if (!abfd->build_id || abfd->build_id->size > size)
 935                 goto out_close;
 936
 937         memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
 938         memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
 939         err = bid->size = abfd->build_id->size;
 940
 941 out_close:
 942         bfd_close(abfd);
 943         return err;
 944 }
 945
 946 #else // HAVE_LIBBFD_BUILDID_SUPPORT
 947
 948 static int read_build_id(const char *filename, struct build_id *bid)
 949 {
 950         size_t size = sizeof(bid->data);
 951         int fd, err = -1;
 952         Elf *elf;
 953
 954         if (size < BUILD_ID_SIZE)
 955                 goto out;
 956
 957         fd = open(filename, O_RDONLY);
 958         if (fd < 0)
 959                 goto out;
 960
 961         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 962         if (elf == NULL) {
 963                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 964                 goto out_close;
 965         }
 966
 967         err = elf_read_build_id(elf, bid->data, size);
 968         if (err > 0)
 969                 bid->size = err;
 970
 971         elf_end(elf);
 972 out_close:
 973         close(fd);
 974 out:
 975         return err;
 976 }
 977
 978 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
 979
 980 int filename__read_build_id(const char *filename, struct build_id *bid)
 981 {
 982         struct kmod_path m = { .name = NULL, };
 983         char path[PATH_MAX];
 984         int err;
 985
 986         if (!filename)
 987                 return -EFAULT;
 988
 989         err = kmod_path__parse(&m, filename);
 990         if (err)
 991                 return -1;
 992
 993         if (m.comp) {
 994                 int error = 0, fd;
 995
 996                 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
 997                 if (fd < 0) {
 998                         pr_debug("Failed to decompress (error %d) %s\n",
 999                                  error, filename);
1000                         return -1;
1001                 }
1002                 close(fd);
1003                 filename = path;
1004         }
1005
1006         err = read_build_id(filename, bid);
1007
1008         if (m.comp)
1009                 unlink(filename);
1010         return err;
1011 }
1012
1013 int sysfs__read_build_id(const char *filename, struct build_id *bid)
1014 {
1015         size_t size = sizeof(bid->data);
1016         int fd, err = -1;
1017
1018         fd = open(filename, O_RDONLY);
1019         if (fd < 0)
1020                 goto out;
1021
1022         while (1) {
1023                 char bf[BUFSIZ];
1024                 GElf_Nhdr nhdr;
1025                 size_t namesz, descsz;
1026
1027                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
1028                         break;
1029
1030                 namesz = NOTE_ALIGN(nhdr.n_namesz);
1031                 descsz = NOTE_ALIGN(nhdr.n_descsz);
1032                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
1033                     nhdr.n_namesz == sizeof("GNU")) {
1034                         if (read(fd, bf, namesz) != (ssize_t)namesz)
1035                                 break;
1036                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
1037                                 size_t sz = min(descsz, size);
1038                                 if (read(fd, bid->data, sz) == (ssize_t)sz) {
1039                                         memset(bid->data + sz, 0, size - sz);
1040                                         bid->size = sz;
1041                                         err = 0;
1042                                         break;
1043                                 }
1044                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
1045                                 break;
1046                 } else {
1047                         int n = namesz + descsz;
1048
1049                         if (n > (int)sizeof(bf)) {
1050                                 n = sizeof(bf);
1051                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
1052                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
1053                         }
1054                         if (read(fd, bf, n) != n)
1055                                 break;
1056                 }
1057         }
1058         close(fd);
1059 out:
1060         return err;
1061 }
1062
1063 #ifdef HAVE_LIBBFD_SUPPORT
1064
1065 int filename__read_debuglink(const char *filename, char *debuglink,
1066                              size_t size)
1067 {
1068         int err = -1;
1069         asection *section;
1070         bfd *abfd;
1071
1072         abfd = bfd_openr(filename, NULL);
1073         if (!abfd)
1074                 return -1;
1075
1076         if (!bfd_check_format(abfd, bfd_object)) {
1077                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
1078                 goto out_close;
1079         }
1080
1081         section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
1082         if (!section)
1083                 goto out_close;
1084
1085         if (section->size > size)
1086                 goto out_close;
1087
1088         if (!bfd_get_section_contents(abfd, section, debuglink, 0,
1089                                       section->size))
1090                 goto out_close;
1091
1092         err = 0;
1093
1094 out_close:
1095         bfd_close(abfd);
1096         return err;
1097 }
1098
1099 #else
1100
1101 int filename__read_debuglink(const char *filename, char *debuglink,
1102                              size_t size)
1103 {
1104         int fd, err = -1;
1105         Elf *elf;
1106         GElf_Ehdr ehdr;
1107         GElf_Shdr shdr;
1108         Elf_Data *data;
1109         Elf_Scn *sec;
1110         Elf_Kind ek;
1111
1112         fd = open(filename, O_RDONLY);
1113         if (fd < 0)
1114                 goto out;
1115
1116         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1117         if (elf == NULL) {
1118                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
1119                 goto out_close;
1120         }
1121
1122         ek = elf_kind(elf);
1123         if (ek != ELF_K_ELF)
1124                 goto out_elf_end;
1125
1126         if (gelf_getehdr(elf, &ehdr) == NULL) {
1127                 pr_err("%s: cannot get elf header.\n", __func__);
1128                 goto out_elf_end;
1129         }
1130
1131         sec = elf_section_by_name(elf, &ehdr, &shdr,
1132                                   ".gnu_debuglink", NULL);
1133         if (sec == NULL)
1134                 goto out_elf_end;
1135
1136         data = elf_getdata(sec, NULL);
1137         if (data == NULL)
1138                 goto out_elf_end;
1139
1140         /* the start of this section is a zero-terminated string */
1141         strncpy(debuglink, data->d_buf, size);
1142
1143         err = 0;
1144
1145 out_elf_end:
1146         elf_end(elf);
1147 out_close:
1148         close(fd);
1149 out:
1150         return err;
1151 }
1152
1153 #endif
1154
1155 static int dso__swap_init(struct dso *dso, unsigned char eidata)
1156 {
1157         static unsigned int const endian = 1;
1158
1159         dso->needs_swap = DSO_SWAP__NO;
1160
1161         switch (eidata) {
1162         case ELFDATA2LSB:
1163                 /* We are big endian, DSO is little endian. */
1164                 if (*(unsigned char const *)&endian != 1)
1165                         dso->needs_swap = DSO_SWAP__YES;
1166                 break;
1167
1168         case ELFDATA2MSB:
1169                 /* We are little endian, DSO is big endian. */
1170                 if (*(unsigned char const *)&endian != 0)
1171                         dso->needs_swap = DSO_SWAP__YES;
1172                 break;
1173
1174         default:
1175                 pr_err("unrecognized DSO data encoding %d\n", eidata);
1176                 return -EINVAL;
1177         }
1178
1179         return 0;
1180 }
1181
1182 bool symsrc__possibly_runtime(struct symsrc *ss)
1183 {
1184         return ss->dynsym || ss->opdsec;
1185 }
1186
1187 bool symsrc__has_symtab(struct symsrc *ss)
1188 {
1189         return ss->symtab != NULL;
1190 }
1191
1192 void symsrc__destroy(struct symsrc *ss)
1193 {
1194         zfree(&ss->name);
1195         elf_end(ss->elf);
1196         close(ss->fd);
1197 }
1198
1199 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
1200 {
1201         /*
1202          * Usually vmlinux is an ELF file with type ET_EXEC for most
1203          * architectures; except Arm64 kernel is linked with option
1204          * '-share', so need to check type ET_DYN.
1205          */
1206         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
1207                ehdr.e_type == ET_DYN;
1208 }
1209
1210 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
1211                  enum dso_binary_type type)
1212 {
1213         GElf_Ehdr ehdr;
1214         Elf *elf;
1215         int fd;
1216
1217         if (dso__needs_decompress(dso)) {
1218                 fd = dso__decompress_kmodule_fd(dso, name);
1219                 if (fd < 0)
1220                         return -1;
1221
1222                 type = dso->symtab_type;
1223         } else {
1224                 fd = open(name, O_RDONLY);
1225                 if (fd < 0) {
1226                         dso->load_errno = errno;
1227                         return -1;
1228                 }
1229         }
1230
1231         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1232         if (elf == NULL) {
1233                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
1234                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
1235                 goto out_close;
1236         }
1237
1238         if (gelf_getehdr(elf, &ehdr) == NULL) {
1239                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
1240                 pr_debug("%s: cannot get elf header.\n", __func__);
1241                 goto out_elf_end;
1242         }
1243
1244         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
1245                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
1246                 goto out_elf_end;
1247         }
1248
1249         /* Always reject images with a mismatched build-id: */
1250         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
1251                 u8 build_id[BUILD_ID_SIZE];
1252                 struct build_id bid;
1253                 int size;
1254
1255                 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
1256                 if (size <= 0) {
1257                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
1258                         goto out_elf_end;
1259                 }
1260
1261                 build_id__init(&bid, build_id, size);
1262                 if (!dso__build_id_equal(dso, &bid)) {
1263                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
1264                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
1265                         goto out_elf_end;
1266                 }
1267         }
1268
1269         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1270
1271         ss->symtab_idx = 0;
1272         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
1273                         &ss->symtab_idx);
1274         if (ss->symshdr.sh_type != SHT_SYMTAB)
1275                 ss->symtab = NULL;
1276
1277         ss->dynsym_idx = 0;
1278         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
1279                         &ss->dynsym_idx);
1280         if (ss->dynshdr.sh_type != SHT_DYNSYM)
1281                 ss->dynsym = NULL;
1282
1283         ss->opdidx = 0;
1284         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
1285                         &ss->opdidx);
1286         if (ss->opdshdr.sh_type != SHT_PROGBITS)
1287                 ss->opdsec = NULL;
1288
1289         if (dso->kernel == DSO_SPACE__USER)
1290                 ss->adjust_symbols = true;
1291         else
1292                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
1293
1294         ss->name   = strdup(name);
1295         if (!ss->name) {
1296                 dso->load_errno = errno;
1297                 goto out_elf_end;
1298         }
1299
1300         ss->elf    = elf;
1301         ss->fd     = fd;
1302         ss->ehdr   = ehdr;
1303         ss->type   = type;
1304
1305         return 0;
1306
1307 out_elf_end:
1308         elf_end(elf);
1309 out_close:
1310         close(fd);
1311         return -1;
1312 }
1313
1314 /**
1315  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
1316  * @kmap: kernel maps and relocation reference symbol
1317  *
1318  * This function returns %true if we are dealing with the kernel maps and the
1319  * relocation reference symbol has not yet been found.  Otherwise %false is
1320  * returned.
1321  */
1322 static bool ref_reloc_sym_not_found(struct kmap *kmap)
1323 {
1324         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
1325                !kmap->ref_reloc_sym->unrelocated_addr;
1326 }
1327
1328 /**
1329  * ref_reloc - kernel relocation offset.
1330  * @kmap: kernel maps and relocation reference symbol
1331  *
1332  * This function returns the offset of kernel addresses as determined by using
1333  * the relocation reference symbol i.e. if the kernel has not been relocated
1334  * then the return value is zero.
1335  */
1336 static u64 ref_reloc(struct kmap *kmap)
1337 {
1338         if (kmap && kmap->ref_reloc_sym &&
1339             kmap->ref_reloc_sym->unrelocated_addr)
1340                 return kmap->ref_reloc_sym->addr -
1341                        kmap->ref_reloc_sym->unrelocated_addr;
1342         return 0;
1343 }
1344
1345 void __weak arch__sym_update(struct symbol *s __maybe_unused,
1346                 GElf_Sym *sym __maybe_unused) { }
1347
1348 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
1349                                       GElf_Sym *sym, GElf_Shdr *shdr,
1350                                       struct maps *kmaps, struct kmap *kmap,
1351                                       struct dso **curr_dsop, struct map **curr_mapp,
1352                                       const char *section_name,
1353                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
1354 {
1355         struct dso *curr_dso = *curr_dsop;
1356         struct map *curr_map;
1357         char dso_name[PATH_MAX];
1358
1359         /* Adjust symbol to map to file offset */
1360         if (adjust_kernel_syms)
1361                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
1362
1363         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
1364                 return 0;
1365
1366         if (strcmp(section_name, ".text") == 0) {
1367                 /*
1368                  * The initial kernel mapping is based on
1369                  * kallsyms and identity maps.  Overwrite it to
1370                  * map to the kernel dso.
1371                  */
1372                 if (*remap_kernel && dso->kernel && !kmodule) {
1373                         *remap_kernel = false;
1374                         map->start = shdr->sh_addr + ref_reloc(kmap);
1375                         map->end = map->start + shdr->sh_size;
1376                         map->pgoff = shdr->sh_offset;
1377                         map->map_ip = map__map_ip;
1378                         map->unmap_ip = map__unmap_ip;
1379                         /* Ensure maps are correctly ordered */
1380                         if (kmaps) {
1381                                 map__get(map);
1382                                 maps__remove(kmaps, map);
1383                                 maps__insert(kmaps, map);
1384                                 map__put(map);
1385                         }
1386                 }
1387
1388                 /*
1389                  * The initial module mapping is based on
1390                  * /proc/modules mapped to offset zero.
1391                  * Overwrite it to map to the module dso.
1392                  */
1393                 if (*remap_kernel && kmodule) {
1394                         *remap_kernel = false;
1395                         map->pgoff = shdr->sh_offset;
1396                 }
1397
1398                 *curr_mapp = map;
1399                 *curr_dsop = dso;
1400                 return 0;
1401         }
1402
1403         if (!kmap)
1404                 return 0;
1405
1406         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
1407
1408         curr_map = maps__find_by_name(kmaps, dso_name);
1409         if (curr_map == NULL) {
1410                 u64 start = sym->st_value;
1411
1412                 if (kmodule)
1413                         start += map->start + shdr->sh_offset;
1414
1415                 curr_dso = dso__new(dso_name);
1416                 if (curr_dso == NULL)
1417                         return -1;
1418                 curr_dso->kernel = dso->kernel;
1419                 curr_dso->long_name = dso->long_name;
1420                 curr_dso->long_name_len = dso->long_name_len;
1421                 curr_map = map__new2(start, curr_dso);
1422                 dso__put(curr_dso);
1423                 if (curr_map == NULL)
1424                         return -1;
1425
1426                 if (curr_dso->kernel)
1427                         map__kmap(curr_map)->kmaps = kmaps;
1428
1429                 if (adjust_kernel_syms) {
1430                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
1431                         curr_map->end    = curr_map->start + shdr->sh_size;
1432                         curr_map->pgoff  = shdr->sh_offset;
1433                 } else {
1434                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
1435                 }
1436                 curr_dso->symtab_type = dso->symtab_type;
1437                 maps__insert(kmaps, curr_map);
1438                 /*
1439                  * Add it before we drop the reference to curr_map, i.e. while
1440                  * we still are sure to have a reference to this DSO via
1441                  * *curr_map->dso.
1442                  */
1443                 dsos__add(&kmaps->machine->dsos, curr_dso);
1444                 /* kmaps already got it */
1445                 map__put(curr_map);
1446                 dso__set_loaded(curr_dso);
1447                 *curr_mapp = curr_map;
1448                 *curr_dsop = curr_dso;
1449         } else
1450                 *curr_dsop = curr_map->dso;
1451
1452         return 0;
1453 }
1454
1455 static int
1456 dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1457                        struct symsrc *runtime_ss, int kmodule, int dynsym)
1458 {
1459         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
1460         struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1461         struct map *curr_map = map;
1462         struct dso *curr_dso = dso;
1463         Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
1464         uint32_t nr_syms;
1465         int err = -1;
1466         uint32_t idx;
1467         GElf_Ehdr ehdr;
1468         GElf_Shdr shdr;
1469         GElf_Shdr tshdr;
1470         Elf_Data *syms, *opddata = NULL;
1471         GElf_Sym sym;
1472         Elf_Scn *sec, *sec_strndx;
1473         Elf *elf;
1474         int nr = 0;
1475         bool remap_kernel = false, adjust_kernel_syms = false;
1476
1477         if (kmap && !kmaps)
1478                 return -1;
1479
1480         elf = syms_ss->elf;
1481         ehdr = syms_ss->ehdr;
1482         if (dynsym) {
1483                 sec  = syms_ss->dynsym;
1484                 shdr = syms_ss->dynshdr;
1485         } else {
1486                 sec =  syms_ss->symtab;
1487                 shdr = syms_ss->symshdr;
1488         }
1489
1490         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1491                                 ".text", NULL))
1492                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1493
1494         if (runtime_ss->opdsec)
1495                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1496
1497         syms = elf_getdata(sec, NULL);
1498         if (syms == NULL)
1499                 goto out_elf_end;
1500
1501         sec = elf_getscn(elf, shdr.sh_link);
1502         if (sec == NULL)
1503                 goto out_elf_end;
1504
1505         symstrs = elf_getdata(sec, NULL);
1506         if (symstrs == NULL)
1507                 goto out_elf_end;
1508
1509         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1510         if (sec_strndx == NULL)
1511                 goto out_elf_end;
1512
1513         secstrs_run = elf_getdata(sec_strndx, NULL);
1514         if (secstrs_run == NULL)
1515                 goto out_elf_end;
1516
1517         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
1518         if (sec_strndx == NULL)
1519                 goto out_elf_end;
1520
1521         secstrs_sym = elf_getdata(sec_strndx, NULL);
1522         if (secstrs_sym == NULL)
1523                 goto out_elf_end;
1524
1525         nr_syms = shdr.sh_size / shdr.sh_entsize;
1526
1527         memset(&sym, 0, sizeof(sym));
1528
1529         /*
1530          * The kernel relocation symbol is needed in advance in order to adjust
1531          * kernel maps correctly.
1532          */
1533         if (ref_reloc_sym_not_found(kmap)) {
1534                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1535                         const char *elf_name = elf_sym__name(&sym, symstrs);
1536
1537                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1538                                 continue;
1539                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1540                         map->reloc = kmap->ref_reloc_sym->addr -
1541                                      kmap->ref_reloc_sym->unrelocated_addr;
1542                         break;
1543                 }
1544         }
1545
1546         /*
1547          * Handle any relocation of vdso necessary because older kernels
1548          * attempted to prelink vdso to its virtual address.
1549          */
1550         if (dso__is_vdso(dso))
1551                 map->reloc = map->start - dso->text_offset;
1552
1553         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1554         /*
1555          * Initial kernel and module mappings do not map to the dso.
1556          * Flag the fixups.
1557          */
1558         if (dso->kernel) {
1559                 remap_kernel = true;
1560                 adjust_kernel_syms = dso->adjust_symbols;
1561         }
1562         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1563                 struct symbol *f;
1564                 const char *elf_name = elf_sym__name(&sym, symstrs);
1565                 char *demangled = NULL;
1566                 int is_label = elf_sym__is_label(&sym);
1567                 const char *section_name;
1568                 bool used_opd = false;
1569
1570                 if (!is_label && !elf_sym__filter(&sym))
1571                         continue;
1572
1573                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1574                  * don't identify functions, so will confuse the profile
1575                  * output: */
1576                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1577                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1578                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1579                                 continue;
1580                 }
1581
1582                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1583                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1584                         u64 *opd = opddata->d_buf + offset;
1585                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1586                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1587                                         sym.st_value);
1588                         used_opd = true;
1589                 }
1590
1591                 /*
1592                  * When loading symbols in a data mapping, ABS symbols (which
1593                  * has a value of SHN_ABS in its st_shndx) failed at
1594                  * elf_getscn().  And it marks the loading as a failure so
1595                  * already loaded symbols cannot be fixed up.
1596                  *
1597                  * I'm not sure what should be done. Just ignore them for now.
1598                  * - Namhyung Kim
1599                  */
1600                 if (sym.st_shndx == SHN_ABS)
1601                         continue;
1602
1603                 sec = elf_getscn(syms_ss->elf, sym.st_shndx);
1604                 if (!sec)
1605                         goto out_elf_end;
1606
1607                 gelf_getshdr(sec, &shdr);
1608
1609                 /*
1610                  * If the attribute bit SHF_ALLOC is not set, the section
1611                  * doesn't occupy memory during process execution.
1612                  * E.g. ".gnu.warning.*" section is used by linker to generate
1613                  * warnings when calling deprecated functions, the symbols in
1614                  * the section aren't loaded to memory during process execution,
1615                  * so skip them.
1616                  */
1617                 if (!(shdr.sh_flags & SHF_ALLOC))
1618                         continue;
1619
1620                 secstrs = secstrs_sym;
1621
1622                 /*
1623                  * We have to fallback to runtime when syms' section header has
1624                  * NOBITS set. NOBITS results in file offset (sh_offset) not
1625                  * being incremented. So sh_offset used below has different
1626                  * values for syms (invalid) and runtime (valid).
1627                  */
1628                 if (shdr.sh_type == SHT_NOBITS) {
1629                         sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1630                         if (!sec)
1631                                 goto out_elf_end;
1632
1633                         gelf_getshdr(sec, &shdr);
1634                         secstrs = secstrs_run;
1635                 }
1636
1637                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1638                         continue;
1639
1640                 section_name = elf_sec__name(&shdr, secstrs);
1641
1642                 /* On ARM, symbols for thumb functions have 1 added to
1643                  * the symbol address as a flag - remove it */
1644                 if ((ehdr.e_machine == EM_ARM) &&
1645                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1646                     (sym.st_value & 1))
1647                         --sym.st_value;
1648
1649                 if (dso->kernel) {
1650                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1651                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1652                                 goto out_elf_end;
1653                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1654                            (!used_opd && syms_ss->adjust_symbols)) {
1655                         GElf_Phdr phdr;
1656
1657                         if (elf_read_program_header(runtime_ss->elf,
1658                                                     (u64)sym.st_value, &phdr)) {
1659                                 pr_debug4("%s: failed to find program header for "
1660                                            "symbol: %s st_value: %#" PRIx64 "\n",
1661                                            __func__, elf_name, (u64)sym.st_value);
1662                                 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1663                                         "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n",
1664                                         __func__, (u64)sym.st_value, (u64)shdr.sh_addr,
1665                                         (u64)shdr.sh_offset);
1666                                 /*
1667                                  * Fail to find program header, let's rollback
1668                                  * to use shdr.sh_addr and shdr.sh_offset to
1669                                  * calibrate symbol's file address, though this
1670                                  * is not necessary for normal C ELF file, we
1671                                  * still need to handle java JIT symbols in this
1672                                  * case.
1673                                  */
1674                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1675                         } else {
1676                                 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1677                                         "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
1678                                         __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
1679                                         (u64)phdr.p_offset);
1680                                 sym.st_value -= phdr.p_vaddr - phdr.p_offset;
1681                         }
1682                 }
1683
1684                 demangled = demangle_sym(dso, kmodule, elf_name);
1685                 if (demangled != NULL)
1686                         elf_name = demangled;
1687
1688                 f = symbol__new(sym.st_value, sym.st_size,
1689                                 GELF_ST_BIND(sym.st_info),
1690                                 GELF_ST_TYPE(sym.st_info), elf_name);
1691                 free(demangled);
1692                 if (!f)
1693                         goto out_elf_end;
1694
1695                 arch__sym_update(f, &sym);
1696
1697                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1698                 nr++;
1699         }
1700
1701         /*
1702          * For misannotated, zeroed, ASM function sizes.
1703          */
1704         if (nr > 0) {
1705                 symbols__fixup_end(&dso->symbols, false);
1706                 symbols__fixup_duplicate(&dso->symbols);
1707                 if (kmap) {
1708                         /*
1709                          * We need to fixup this here too because we create new
1710                          * maps here, for things like vsyscall sections.
1711                          */
1712                         maps__fixup_end(kmaps);
1713                 }
1714         }
1715         err = nr;
1716 out_elf_end:
1717         return err;
1718 }
1719
1720 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1721                   struct symsrc *runtime_ss, int kmodule)
1722 {
1723         int nr = 0;
1724         int err = -1;
1725
1726         dso->symtab_type = syms_ss->type;
1727         dso->is_64_bit = syms_ss->is_64_bit;
1728         dso->rel = syms_ss->ehdr.e_type == ET_REL;
1729
1730         /*
1731          * Modules may already have symbols from kallsyms, but those symbols
1732          * have the wrong values for the dso maps, so remove them.
1733          */
1734         if (kmodule && syms_ss->symtab)
1735                 symbols__delete(&dso->symbols);
1736
1737         if (!syms_ss->symtab) {
1738                 /*
1739                  * If the vmlinux is stripped, fail so we will fall back
1740                  * to using kallsyms. The vmlinux runtime symbols aren't
1741                  * of much use.
1742                  */
1743                 if (dso->kernel)
1744                         return err;
1745         } else  {
1746                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1747                                              kmodule, 0);
1748                 if (err < 0)
1749                         return err;
1750                 nr = err;
1751         }
1752
1753         if (syms_ss->dynsym) {
1754                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1755                                              kmodule, 1);
1756                 if (err < 0)
1757                         return err;
1758                 err += nr;
1759         }
1760
1761         return err;
1762 }
1763
1764 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1765 {
1766         GElf_Phdr phdr;
1767         size_t i, phdrnum;
1768         int err;
1769         u64 sz;
1770
1771         if (elf_getphdrnum(elf, &phdrnum))
1772                 return -1;
1773
1774         for (i = 0; i < phdrnum; i++) {
1775                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1776                         return -1;
1777                 if (phdr.p_type != PT_LOAD)
1778                         continue;
1779                 if (exe) {
1780                         if (!(phdr.p_flags & PF_X))
1781                                 continue;
1782                 } else {
1783                         if (!(phdr.p_flags & PF_R))
1784                                 continue;
1785                 }
1786                 sz = min(phdr.p_memsz, phdr.p_filesz);
1787                 if (!sz)
1788                         continue;
1789                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1790                 if (err)
1791                         return err;
1792         }
1793         return 0;
1794 }
1795
1796 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1797                     bool *is_64_bit)
1798 {
1799         int err;
1800         Elf *elf;
1801
1802         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1803         if (elf == NULL)
1804                 return -1;
1805
1806         if (is_64_bit)
1807                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1808
1809         err = elf_read_maps(elf, exe, mapfn, data);
1810
1811         elf_end(elf);
1812         return err;
1813 }
1814
1815 enum dso_type dso__type_fd(int fd)
1816 {
1817         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1818         GElf_Ehdr ehdr;
1819         Elf_Kind ek;
1820         Elf *elf;
1821
1822         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1823         if (elf == NULL)
1824                 goto out;
1825
1826         ek = elf_kind(elf);
1827         if (ek != ELF_K_ELF)
1828                 goto out_end;
1829
1830         if (gelf_getclass(elf) == ELFCLASS64) {
1831                 dso_type = DSO__TYPE_64BIT;
1832                 goto out_end;
1833         }
1834
1835         if (gelf_getehdr(elf, &ehdr) == NULL)
1836                 goto out_end;
1837
1838         if (ehdr.e_machine == EM_X86_64)
1839                 dso_type = DSO__TYPE_X32BIT;
1840         else
1841                 dso_type = DSO__TYPE_32BIT;
1842 out_end:
1843         elf_end(elf);
1844 out:
1845         return dso_type;
1846 }
1847
1848 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1849 {
1850         ssize_t r;
1851         size_t n;
1852         int err = -1;
1853         char *buf = malloc(page_size);
1854
1855         if (buf == NULL)
1856                 return -1;
1857
1858         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1859                 goto out;
1860
1861         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1862                 goto out;
1863
1864         while (len) {
1865                 n = page_size;
1866                 if (len < n)
1867                         n = len;
1868                 /* Use read because mmap won't work on proc files */
1869                 r = read(from, buf, n);
1870                 if (r < 0)
1871                         goto out;
1872                 if (!r)
1873                         break;
1874                 n = r;
1875                 r = write(to, buf, n);
1876                 if (r < 0)
1877                         goto out;
1878                 if ((size_t)r != n)
1879                         goto out;
1880                 len -= n;
1881         }
1882
1883         err = 0;
1884 out:
1885         free(buf);
1886         return err;
1887 }
1888
1889 struct kcore {
1890         int fd;
1891         int elfclass;
1892         Elf *elf;
1893         GElf_Ehdr ehdr;
1894 };
1895
1896 static int kcore__open(struct kcore *kcore, const char *filename)
1897 {
1898         GElf_Ehdr *ehdr;
1899
1900         kcore->fd = open(filename, O_RDONLY);
1901         if (kcore->fd == -1)
1902                 return -1;
1903
1904         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1905         if (!kcore->elf)
1906                 goto out_close;
1907
1908         kcore->elfclass = gelf_getclass(kcore->elf);
1909         if (kcore->elfclass == ELFCLASSNONE)
1910                 goto out_end;
1911
1912         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1913         if (!ehdr)
1914                 goto out_end;
1915
1916         return 0;
1917
1918 out_end:
1919         elf_end(kcore->elf);
1920 out_close:
1921         close(kcore->fd);
1922         return -1;
1923 }
1924
1925 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1926                        bool temp)
1927 {
1928         kcore->elfclass = elfclass;
1929
1930         if (temp)
1931                 kcore->fd = mkstemp(filename);
1932         else
1933                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1934         if (kcore->fd == -1)
1935                 return -1;
1936
1937         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1938         if (!kcore->elf)
1939                 goto out_close;
1940
1941         if (!gelf_newehdr(kcore->elf, elfclass))
1942                 goto out_end;
1943
1944         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1945
1946         return 0;
1947
1948 out_end:
1949         elf_end(kcore->elf);
1950 out_close:
1951         close(kcore->fd);
1952         unlink(filename);
1953         return -1;
1954 }
1955
1956 static void kcore__close(struct kcore *kcore)
1957 {
1958         elf_end(kcore->elf);
1959         close(kcore->fd);
1960 }
1961
1962 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1963 {
1964         GElf_Ehdr *ehdr = &to->ehdr;
1965         GElf_Ehdr *kehdr = &from->ehdr;
1966
1967         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1968         ehdr->e_type      = kehdr->e_type;
1969         ehdr->e_machine   = kehdr->e_machine;
1970         ehdr->e_version   = kehdr->e_version;
1971         ehdr->e_entry     = 0;
1972         ehdr->e_shoff     = 0;
1973         ehdr->e_flags     = kehdr->e_flags;
1974         ehdr->e_phnum     = count;
1975         ehdr->e_shentsize = 0;
1976         ehdr->e_shnum     = 0;
1977         ehdr->e_shstrndx  = 0;
1978
1979         if (from->elfclass == ELFCLASS32) {
1980                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1981                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1982                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1983         } else {
1984                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1985                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1986                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1987         }
1988
1989         if (!gelf_update_ehdr(to->elf, ehdr))
1990                 return -1;
1991
1992         if (!gelf_newphdr(to->elf, count))
1993                 return -1;
1994
1995         return 0;
1996 }
1997
1998 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1999                            u64 addr, u64 len)
2000 {
2001         GElf_Phdr phdr = {
2002                 .p_type         = PT_LOAD,
2003                 .p_flags        = PF_R | PF_W | PF_X,
2004                 .p_offset       = offset,
2005                 .p_vaddr        = addr,
2006                 .p_paddr        = 0,
2007                 .p_filesz       = len,
2008                 .p_memsz        = len,
2009                 .p_align        = page_size,
2010         };
2011
2012         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
2013                 return -1;
2014
2015         return 0;
2016 }
2017
2018 static off_t kcore__write(struct kcore *kcore)
2019 {
2020         return elf_update(kcore->elf, ELF_C_WRITE);
2021 }
2022
2023 struct phdr_data {
2024         off_t offset;
2025         off_t rel;
2026         u64 addr;
2027         u64 len;
2028         struct list_head node;
2029         struct phdr_data *remaps;
2030 };
2031
2032 struct sym_data {
2033         u64 addr;
2034         struct list_head node;
2035 };
2036
2037 struct kcore_copy_info {
2038         u64 stext;
2039         u64 etext;
2040         u64 first_symbol;
2041         u64 last_symbol;
2042         u64 first_module;
2043         u64 first_module_symbol;
2044         u64 last_module_symbol;
2045         size_t phnum;
2046         struct list_head phdrs;
2047         struct list_head syms;
2048 };
2049
2050 #define kcore_copy__for_each_phdr(k, p) \
2051         list_for_each_entry((p), &(k)->phdrs, node)
2052
2053 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
2054 {
2055         struct phdr_data *p = zalloc(sizeof(*p));
2056
2057         if (p) {
2058                 p->addr   = addr;
2059                 p->len    = len;
2060                 p->offset = offset;
2061         }
2062
2063         return p;
2064 }
2065
2066 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
2067                                                  u64 addr, u64 len,
2068                                                  off_t offset)
2069 {
2070         struct phdr_data *p = phdr_data__new(addr, len, offset);
2071
2072         if (p)
2073                 list_add_tail(&p->node, &kci->phdrs);
2074
2075         return p;
2076 }
2077
2078 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
2079 {
2080         struct phdr_data *p, *tmp;
2081
2082         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
2083                 list_del_init(&p->node);
2084                 free(p);
2085         }
2086 }
2087
2088 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
2089                                             u64 addr)
2090 {
2091         struct sym_data *s = zalloc(sizeof(*s));
2092
2093         if (s) {
2094                 s->addr = addr;
2095                 list_add_tail(&s->node, &kci->syms);
2096         }
2097
2098         return s;
2099 }
2100
2101 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
2102 {
2103         struct sym_data *s, *tmp;
2104
2105         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
2106                 list_del_init(&s->node);
2107                 free(s);
2108         }
2109 }
2110
2111 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
2112                                         u64 start)
2113 {
2114         struct kcore_copy_info *kci = arg;
2115
2116         if (!kallsyms__is_function(type))
2117                 return 0;
2118
2119         if (strchr(name, '[')) {
2120                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
2121                         kci->first_module_symbol = start;
2122                 if (start > kci->last_module_symbol)
2123                         kci->last_module_symbol = start;
2124                 return 0;
2125         }
2126
2127         if (!kci->first_symbol || start < kci->first_symbol)
2128                 kci->first_symbol = start;
2129
2130         if (!kci->last_symbol || start > kci->last_symbol)
2131                 kci->last_symbol = start;
2132
2133         if (!strcmp(name, "_stext")) {
2134                 kci->stext = start;
2135                 return 0;
2136         }
2137
2138         if (!strcmp(name, "_etext")) {
2139                 kci->etext = start;
2140                 return 0;
2141         }
2142
2143         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
2144                 return -1;
2145
2146         return 0;
2147 }
2148
2149 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
2150                                       const char *dir)
2151 {
2152         char kallsyms_filename[PATH_MAX];
2153
2154         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
2155
2156         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
2157                 return -1;
2158
2159         if (kallsyms__parse(kallsyms_filename, kci,
2160                             kcore_copy__process_kallsyms) < 0)
2161                 return -1;
2162
2163         return 0;
2164 }
2165
2166 static int kcore_copy__process_modules(void *arg,
2167                                        const char *name __maybe_unused,
2168                                        u64 start, u64 size __maybe_unused)
2169 {
2170         struct kcore_copy_info *kci = arg;
2171
2172         if (!kci->first_module || start < kci->first_module)
2173                 kci->first_module = start;
2174
2175         return 0;
2176 }
2177
2178 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
2179                                      const char *dir)
2180 {
2181         char modules_filename[PATH_MAX];
2182
2183         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
2184
2185         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
2186                 return -1;
2187
2188         if (modules__parse(modules_filename, kci,
2189                            kcore_copy__process_modules) < 0)
2190                 return -1;
2191
2192         return 0;
2193 }
2194
2195 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
2196                            u64 pgoff, u64 s, u64 e)
2197 {
2198         u64 len, offset;
2199
2200         if (s < start || s >= end)
2201                 return 0;
2202
2203         offset = (s - start) + pgoff;
2204         len = e < end ? e - s : end - s;
2205
2206         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
2207 }
2208
2209 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
2210 {
2211         struct kcore_copy_info *kci = data;
2212         u64 end = start + len;
2213         struct sym_data *sdat;
2214
2215         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
2216                 return -1;
2217
2218         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
2219                             kci->last_module_symbol))
2220                 return -1;
2221
2222         list_for_each_entry(sdat, &kci->syms, node) {
2223                 u64 s = round_down(sdat->addr, page_size);
2224
2225                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
2226                         return -1;
2227         }
2228
2229         return 0;
2230 }
2231
2232 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
2233 {
2234         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
2235                 return -1;
2236
2237         return 0;
2238 }
2239
2240 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
2241 {
2242         struct phdr_data *p, *k = NULL;
2243         u64 kend;
2244
2245         if (!kci->stext)
2246                 return;
2247
2248         /* Find phdr that corresponds to the kernel map (contains stext) */
2249         kcore_copy__for_each_phdr(kci, p) {
2250                 u64 pend = p->addr + p->len - 1;
2251
2252                 if (p->addr <= kci->stext && pend >= kci->stext) {
2253                         k = p;
2254                         break;
2255                 }
2256         }
2257
2258         if (!k)
2259                 return;
2260
2261         kend = k->offset + k->len;
2262
2263         /* Find phdrs that remap the kernel */
2264         kcore_copy__for_each_phdr(kci, p) {
2265                 u64 pend = p->offset + p->len;
2266
2267                 if (p == k)
2268                         continue;
2269
2270                 if (p->offset >= k->offset && pend <= kend)
2271                         p->remaps = k;
2272         }
2273 }
2274
2275 static void kcore_copy__layout(struct kcore_copy_info *kci)
2276 {
2277         struct phdr_data *p;
2278         off_t rel = 0;
2279
2280         kcore_copy__find_remaps(kci);
2281
2282         kcore_copy__for_each_phdr(kci, p) {
2283                 if (!p->remaps) {
2284                         p->rel = rel;
2285                         rel += p->len;
2286                 }
2287                 kci->phnum += 1;
2288         }
2289
2290         kcore_copy__for_each_phdr(kci, p) {
2291                 struct phdr_data *k = p->remaps;
2292
2293                 if (k)
2294                         p->rel = p->offset - k->offset + k->rel;
2295         }
2296 }
2297
2298 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
2299                                  Elf *elf)
2300 {
2301         if (kcore_copy__parse_kallsyms(kci, dir))
2302                 return -1;
2303
2304         if (kcore_copy__parse_modules(kci, dir))
2305                 return -1;
2306
2307         if (kci->stext)
2308                 kci->stext = round_down(kci->stext, page_size);
2309         else
2310                 kci->stext = round_down(kci->first_symbol, page_size);
2311
2312         if (kci->etext) {
2313                 kci->etext = round_up(kci->etext, page_size);
2314         } else if (kci->last_symbol) {
2315                 kci->etext = round_up(kci->last_symbol, page_size);
2316                 kci->etext += page_size;
2317         }
2318
2319         if (kci->first_module_symbol &&
2320             (!kci->first_module || kci->first_module_symbol < kci->first_module))
2321                 kci->first_module = kci->first_module_symbol;
2322
2323         kci->first_module = round_down(kci->first_module, page_size);
2324
2325         if (kci->last_module_symbol) {
2326                 kci->last_module_symbol = round_up(kci->last_module_symbol,
2327                                                    page_size);
2328                 kci->last_module_symbol += page_size;
2329         }
2330
2331         if (!kci->stext || !kci->etext)
2332                 return -1;
2333
2334         if (kci->first_module && !kci->last_module_symbol)
2335                 return -1;
2336
2337         if (kcore_copy__read_maps(kci, elf))
2338                 return -1;
2339
2340         kcore_copy__layout(kci);
2341
2342         return 0;
2343 }
2344
2345 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
2346                                  const char *name)
2347 {
2348         char from_filename[PATH_MAX];
2349         char to_filename[PATH_MAX];
2350
2351         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2352         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2353
2354         return copyfile_mode(from_filename, to_filename, 0400);
2355 }
2356
2357 static int kcore_copy__unlink(const char *dir, const char *name)
2358 {
2359         char filename[PATH_MAX];
2360
2361         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
2362
2363         return unlink(filename);
2364 }
2365
2366 static int kcore_copy__compare_fds(int from, int to)
2367 {
2368         char *buf_from;
2369         char *buf_to;
2370         ssize_t ret;
2371         size_t len;
2372         int err = -1;
2373
2374         buf_from = malloc(page_size);
2375         buf_to = malloc(page_size);
2376         if (!buf_from || !buf_to)
2377                 goto out;
2378
2379         while (1) {
2380                 /* Use read because mmap won't work on proc files */
2381                 ret = read(from, buf_from, page_size);
2382                 if (ret < 0)
2383                         goto out;
2384
2385                 if (!ret)
2386                         break;
2387
2388                 len = ret;
2389
2390                 if (readn(to, buf_to, len) != (int)len)
2391                         goto out;
2392
2393                 if (memcmp(buf_from, buf_to, len))
2394                         goto out;
2395         }
2396
2397         err = 0;
2398 out:
2399         free(buf_to);
2400         free(buf_from);
2401         return err;
2402 }
2403
2404 static int kcore_copy__compare_files(const char *from_filename,
2405                                      const char *to_filename)
2406 {
2407         int from, to, err = -1;
2408
2409         from = open(from_filename, O_RDONLY);
2410         if (from < 0)
2411                 return -1;
2412
2413         to = open(to_filename, O_RDONLY);
2414         if (to < 0)
2415                 goto out_close_from;
2416
2417         err = kcore_copy__compare_fds(from, to);
2418
2419         close(to);
2420 out_close_from:
2421         close(from);
2422         return err;
2423 }
2424
2425 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
2426                                     const char *name)
2427 {
2428         char from_filename[PATH_MAX];
2429         char to_filename[PATH_MAX];
2430
2431         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2432         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2433
2434         return kcore_copy__compare_files(from_filename, to_filename);
2435 }
2436
2437 /**
2438  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
2439  * @from_dir: from directory
2440  * @to_dir: to directory
2441  *
2442  * This function copies kallsyms, modules and kcore files from one directory to
2443  * another.  kallsyms and modules are copied entirely.  Only code segments are
2444  * copied from kcore.  It is assumed that two segments suffice: one for the
2445  * kernel proper and one for all the modules.  The code segments are determined
2446  * from kallsyms and modules files.  The kernel map starts at _stext or the
2447  * lowest function symbol, and ends at _etext or the highest function symbol.
2448  * The module map starts at the lowest module address and ends at the highest
2449  * module symbol.  Start addresses are rounded down to the nearest page.  End
2450  * addresses are rounded up to the nearest page.  An extra page is added to the
2451  * highest kernel symbol and highest module symbol to, hopefully, encompass that
2452  * symbol too.  Because it contains only code sections, the resulting kcore is
2453  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
2454  * is not the same for the kernel map and the modules map.  That happens because
2455  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
2456  * kallsyms file is compared with its copy to check that modules have not been
2457  * loaded or unloaded while the copies were taking place.
2458  *
2459  * Return: %0 on success, %-1 on failure.
2460  */
2461 int kcore_copy(const char *from_dir, const char *to_dir)
2462 {
2463         struct kcore kcore;
2464         struct kcore extract;
2465         int idx = 0, err = -1;
2466         off_t offset, sz;
2467         struct kcore_copy_info kci = { .stext = 0, };
2468         char kcore_filename[PATH_MAX];
2469         char extract_filename[PATH_MAX];
2470         struct phdr_data *p;
2471
2472         INIT_LIST_HEAD(&kci.phdrs);
2473         INIT_LIST_HEAD(&kci.syms);
2474
2475         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2476                 return -1;
2477
2478         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2479                 goto out_unlink_kallsyms;
2480
2481         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2482         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2483
2484         if (kcore__open(&kcore, kcore_filename))
2485                 goto out_unlink_modules;
2486
2487         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2488                 goto out_kcore_close;
2489
2490         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2491                 goto out_kcore_close;
2492
2493         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2494                 goto out_extract_close;
2495
2496         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2497                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2498         offset = round_up(offset, page_size);
2499
2500         kcore_copy__for_each_phdr(&kci, p) {
2501                 off_t offs = p->rel + offset;
2502
2503                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2504                         goto out_extract_close;
2505         }
2506
2507         sz = kcore__write(&extract);
2508         if (sz < 0 || sz > offset)
2509                 goto out_extract_close;
2510
2511         kcore_copy__for_each_phdr(&kci, p) {
2512                 off_t offs = p->rel + offset;
2513
2514                 if (p->remaps)
2515                         continue;
2516                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2517                         goto out_extract_close;
2518         }
2519
2520         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2521                 goto out_extract_close;
2522
2523         err = 0;
2524
2525 out_extract_close:
2526         kcore__close(&extract);
2527         if (err)
2528                 unlink(extract_filename);
2529 out_kcore_close:
2530         kcore__close(&kcore);
2531 out_unlink_modules:
2532         if (err)
2533                 kcore_copy__unlink(to_dir, "modules");
2534 out_unlink_kallsyms:
2535         if (err)
2536                 kcore_copy__unlink(to_dir, "kallsyms");
2537
2538         kcore_copy__free_phdrs(&kci);
2539         kcore_copy__free_syms(&kci);
2540
2541         return err;
2542 }
2543
2544 int kcore_extract__create(struct kcore_extract *kce)
2545 {
2546         struct kcore kcore;
2547         struct kcore extract;
2548         size_t count = 1;
2549         int idx = 0, err = -1;
2550         off_t offset = page_size, sz;
2551
2552         if (kcore__open(&kcore, kce->kcore_filename))
2553                 return -1;
2554
2555         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2556         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2557                 goto out_kcore_close;
2558
2559         if (kcore__copy_hdr(&kcore, &extract, count))
2560                 goto out_extract_close;
2561
2562         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2563                 goto out_extract_close;
2564
2565         sz = kcore__write(&extract);
2566         if (sz < 0 || sz > offset)
2567                 goto out_extract_close;
2568
2569         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2570                 goto out_extract_close;
2571
2572         err = 0;
2573
2574 out_extract_close:
2575         kcore__close(&extract);
2576         if (err)
2577                 unlink(kce->extract_filename);
2578 out_kcore_close:
2579         kcore__close(&kcore);
2580
2581         return err;
2582 }
2583
2584 void kcore_extract__delete(struct kcore_extract *kce)
2585 {
2586         unlink(kce->extract_filename);
2587 }
2588
2589 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2590
2591 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2592 {
2593         if (!base_off)
2594                 return;
2595
2596         if (tmp->bit32)
2597                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2598                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2599                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2600         else
2601                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2602                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2603                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2604 }
2605
2606 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2607                               GElf_Addr base_off)
2608 {
2609         if (!base_off)
2610                 return;
2611
2612         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2613                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2614         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2615                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2616 }
2617
2618 /**
2619  * populate_sdt_note : Parse raw data and identify SDT note
2620  * @elf: elf of the opened file
2621  * @data: raw data of a section with description offset applied
2622  * @len: note description size
2623  * @type: type of the note
2624  * @sdt_notes: List to add the SDT note
2625  *
2626  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2627  * if its an SDT note, it appends to @sdt_notes list.
2628  */
2629 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2630                              struct list_head *sdt_notes)
2631 {
2632         const char *provider, *name, *args;
2633         struct sdt_note *tmp = NULL;
2634         GElf_Ehdr ehdr;
2635         GElf_Shdr shdr;
2636         int ret = -EINVAL;
2637
2638         union {
2639                 Elf64_Addr a64[NR_ADDR];
2640                 Elf32_Addr a32[NR_ADDR];
2641         } buf;
2642
2643         Elf_Data dst = {
2644                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2645                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2646                 .d_off = 0, .d_align = 0
2647         };
2648         Elf_Data src = {
2649                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2650                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2651                 .d_align = 0
2652         };
2653
2654         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2655         if (!tmp) {
2656                 ret = -ENOMEM;
2657                 goto out_err;
2658         }
2659
2660         INIT_LIST_HEAD(&tmp->note_list);
2661
2662         if (len < dst.d_size + 3)
2663                 goto out_free_note;
2664
2665         /* Translation from file representation to memory representation */
2666         if (gelf_xlatetom(*elf, &dst, &src,
2667                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2668                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2669                 goto out_free_note;
2670         }
2671
2672         /* Populate the fields of sdt_note */
2673         provider = data + dst.d_size;
2674
2675         name = (const char *)memchr(provider, '\0', data + len - provider);
2676         if (name++ == NULL)
2677                 goto out_free_note;
2678
2679         tmp->provider = strdup(provider);
2680         if (!tmp->provider) {
2681                 ret = -ENOMEM;
2682                 goto out_free_note;
2683         }
2684         tmp->name = strdup(name);
2685         if (!tmp->name) {
2686                 ret = -ENOMEM;
2687                 goto out_free_prov;
2688         }
2689
2690         args = memchr(name, '\0', data + len - name);
2691
2692         /*
2693          * There is no argument if:
2694          * - We reached the end of the note;
2695          * - There is not enough room to hold a potential string;
2696          * - The argument string is empty or just contains ':'.
2697          */
2698         if (args == NULL || data + len - args < 2 ||
2699                 args[1] == ':' || args[1] == '\0')
2700                 tmp->args = NULL;
2701         else {
2702                 tmp->args = strdup(++args);
2703                 if (!tmp->args) {
2704                         ret = -ENOMEM;
2705                         goto out_free_name;
2706                 }
2707         }
2708
2709         if (gelf_getclass(*elf) == ELFCLASS32) {
2710                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2711                 tmp->bit32 = true;
2712         } else {
2713                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2714                 tmp->bit32 = false;
2715         }
2716
2717         if (!gelf_getehdr(*elf, &ehdr)) {
2718                 pr_debug("%s : cannot get elf header.\n", __func__);
2719                 ret = -EBADF;
2720                 goto out_free_args;
2721         }
2722
2723         /* Adjust the prelink effect :
2724          * Find out the .stapsdt.base section.
2725          * This scn will help us to handle prelinking (if present).
2726          * Compare the retrieved file offset of the base section with the
2727          * base address in the description of the SDT note. If its different,
2728          * then accordingly, adjust the note location.
2729          */
2730         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2731                 sdt_adjust_loc(tmp, shdr.sh_offset);
2732
2733         /* Adjust reference counter offset */
2734         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2735                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2736
2737         list_add_tail(&tmp->note_list, sdt_notes);
2738         return 0;
2739
2740 out_free_args:
2741         zfree(&tmp->args);
2742 out_free_name:
2743         zfree(&tmp->name);
2744 out_free_prov:
2745         zfree(&tmp->provider);
2746 out_free_note:
2747         free(tmp);
2748 out_err:
2749         return ret;
2750 }
2751
2752 /**
2753  * construct_sdt_notes_list : constructs a list of SDT notes
2754  * @elf : elf to look into
2755  * @sdt_notes : empty list_head
2756  *
2757  * Scans the sections in 'elf' for the section
2758  * .note.stapsdt. It, then calls populate_sdt_note to find
2759  * out the SDT events and populates the 'sdt_notes'.
2760  */
2761 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2762 {
2763         GElf_Ehdr ehdr;
2764         Elf_Scn *scn = NULL;
2765         Elf_Data *data;
2766         GElf_Shdr shdr;
2767         size_t shstrndx, next;
2768         GElf_Nhdr nhdr;
2769         size_t name_off, desc_off, offset;
2770         int ret = 0;
2771
2772         if (gelf_getehdr(elf, &ehdr) == NULL) {
2773                 ret = -EBADF;
2774                 goto out_ret;
2775         }
2776         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2777                 ret = -EBADF;
2778                 goto out_ret;
2779         }
2780
2781         /* Look for the required section */
2782         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2783         if (!scn) {
2784                 ret = -ENOENT;
2785                 goto out_ret;
2786         }
2787
2788         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2789                 ret = -ENOENT;
2790                 goto out_ret;
2791         }
2792
2793         data = elf_getdata(scn, NULL);
2794
2795         /* Get the SDT notes */
2796         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2797                                               &desc_off)) > 0; offset = next) {
2798                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2799                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2800                             sizeof(SDT_NOTE_NAME))) {
2801                         /* Check the type of the note */
2802                         if (nhdr.n_type != SDT_NOTE_TYPE)
2803                                 goto out_ret;
2804
2805                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2806                                                 nhdr.n_descsz, sdt_notes);
2807                         if (ret < 0)
2808                                 goto out_ret;
2809                 }
2810         }
2811         if (list_empty(sdt_notes))
2812                 ret = -ENOENT;
2813
2814 out_ret:
2815         return ret;
2816 }
2817
2818 /**
2819  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2820  * @head : empty list_head
2821  * @target : file to find SDT notes from
2822  *
2823  * This opens the file, initializes
2824  * the ELF and then calls construct_sdt_notes_list.
2825  */
2826 int get_sdt_note_list(struct list_head *head, const char *target)
2827 {
2828         Elf *elf;
2829         int fd, ret;
2830
2831         fd = open(target, O_RDONLY);
2832         if (fd < 0)
2833                 return -EBADF;
2834
2835         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2836         if (!elf) {
2837                 ret = -EBADF;
2838                 goto out_close;
2839         }
2840         ret = construct_sdt_notes_list(elf, head);
2841         elf_end(elf);
2842 out_close:
2843         close(fd);
2844         return ret;
2845 }
2846
2847 /**
2848  * cleanup_sdt_note_list : free the sdt notes' list
2849  * @sdt_notes: sdt notes' list
2850  *
2851  * Free up the SDT notes in @sdt_notes.
2852  * Returns the number of SDT notes free'd.
2853  */
2854 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2855 {
2856         struct sdt_note *tmp, *pos;
2857         int nr_free = 0;
2858
2859         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2860                 list_del_init(&pos->note_list);
2861                 zfree(&pos->args);
2862                 zfree(&pos->name);
2863                 zfree(&pos->provider);
2864                 free(pos);
2865                 nr_free++;
2866         }
2867         return nr_free;
2868 }
2869
2870 /**
2871  * sdt_notes__get_count: Counts the number of sdt events
2872  * @start: list_head to sdt_notes list
2873  *
2874  * Returns the number of SDT notes in a list
2875  */
2876 int sdt_notes__get_count(struct list_head *start)
2877 {
2878         struct sdt_note *sdt_ptr;
2879         int count = 0;
2880
2881         list_for_each_entry(sdt_ptr, start, note_list)
2882                 count++;
2883         return count;
2884 }
2885 #endif
2886
2887 void symbol__elf_init(void)
2888 {
2889         elf_version(EV_CURRENT);
2890 }