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main
src/objdump.c
796 строк
20 KB
Anton Moryakov
objdump: Handle elf_getarhdr returning NULL in handle_ar
08 фев 2025, 01:02
08 фев 2025, 01:02
6c76ce7
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/* Print information from ELF file in human-readable form. Copyright (C) 2005, 2006, 2007, 2009, 2011, 2012, 2014, 2015 Red Hat, Inc. This file is part of elfutils. Written by Ulrich Drepper <drepper@redhat.com>, 2005. This file is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. elfutils is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #ifdef HAVE_CONFIG_H # include <config.h> #endif #include <argp.h> #include <fcntl.h> #include <inttypes.h> #include <locale.h> #include <stdbool.h> #include <stdio.h> #include <stdio_ext.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <libeu.h> #include <system.h> #include <color.h> #include <printversion.h> #include "../libebl/libeblP.h" /* Name and version of program. */ ARGP_PROGRAM_VERSION_HOOK_DEF = print_version; /* Bug report address. */ ARGP_PROGRAM_BUG_ADDRESS_DEF = PACKAGE_BUGREPORT; /* Definitions of arguments for argp functions. */ static const struct argp_option options[] = { { NULL, 0, NULL, 0, N_("Mode selection:"), 0 }, { "reloc", 'r', NULL, 0, N_("Display relocation information."), 0 }, { "full-contents", 's', NULL, 0, N_("Display the full contents of all sections requested"), 0 }, { "disassemble", 'd', NULL, 0, N_("Display assembler code of executable sections"), 0 }, { NULL, 0, NULL, 0, N_("Output content selection:"), 0 }, { "section", 'j', "NAME", 0, N_("Only display information for section NAME."), 0 }, { NULL, 0, NULL, 0, NULL, 0 } }; /* Short description of program. */ static const char doc[] = N_("\ Show information from FILEs (a.out by default)."); /* Strings for arguments in help texts. */ static const char args_doc[] = N_("[FILE...]"); /* Prototype for option handler. */ static error_t parse_opt (int key, char *arg, struct argp_state *state); /* Parser children. */ static struct argp_child argp_children[] = { { &color_argp, 0, N_("Output formatting"), 2 }, { NULL, 0, NULL, 0} }; /* Data structure to communicate with argp functions. */ static const struct argp argp = { options, parse_opt, args_doc, doc, argp_children, NULL, NULL }; /* Print symbols in file named FNAME. */ static int process_file (const char *fname, bool more_than_one); /* Handle content of archive. */ static int handle_ar (int fd, Elf *elf, const char *prefix, const char *fname, const char *suffix); /* Handle ELF file. */ static int handle_elf (Elf *elf, const char *prefix, const char *fname, const char *suffix); #define INTERNAL_ERROR(fname) \ error_exit (0, _("%s: INTERNAL ERROR %d (%s): %s"), \ fname, __LINE__, PACKAGE_VERSION, elf_errmsg (-1)) /* List of sections which should be used. */ static struct section_list { bool is_name; union { const char *name; uint32_t scnndx; }; struct section_list *next; } *section_list; /* If true print archive index. */ static bool print_relocs; /* If true print full contents of requested sections. */ static bool print_full_content; /* If true print disassembled output.. */ static bool print_disasm; int main (int argc, char *argv[]) { /* We use no threads here which can interfere with handling a stream. */ (void) __fsetlocking (stdin, FSETLOCKING_BYCALLER); (void) __fsetlocking (stdout, FSETLOCKING_BYCALLER); (void) __fsetlocking (stderr, FSETLOCKING_BYCALLER); /* Set locale. */ (void) setlocale (LC_ALL, ""); /* Make sure the message catalog can be found. */ (void) bindtextdomain (PACKAGE_TARNAME, LOCALEDIR); /* Initialize the message catalog. */ (void) textdomain (PACKAGE_TARNAME); /* Parse and process arguments. */ int remaining; (void) argp_parse (&argp, argc, argv, 0, &remaining, NULL); /* Tell the library which version we are expecting. */ (void) elf_version (EV_CURRENT); int result = 0; if (remaining == argc) /* The user didn't specify a name so we use a.out. */ result = process_file ("a.out", false); else { /* Process all the remaining files. */ const bool more_than_one = remaining + 1 < argc; do result |= process_file (argv[remaining], more_than_one); while (++remaining < argc); } return result; } /* Handle program arguments. */ static error_t parse_opt (int key, char *arg, struct argp_state *state __attribute__ ((unused))) { /* True if any of the control options is set. */ static bool any_control_option; switch (key) { case 'j': { struct section_list *newp = xmalloc (sizeof (*newp)); char *endp; newp->scnndx = strtoul (arg, &endp, 0); if (*endp == 0) newp->is_name = false; else { newp->name = arg; newp->is_name = true; } newp->next = section_list; section_list = newp; } any_control_option = true; break; case 'd': print_disasm = true; any_control_option = true; break; case 'r': print_relocs = true; any_control_option = true; break; case 's': print_full_content = true; any_control_option = true; break; case ARGP_KEY_FINI: if (! any_control_option) { fputs (_("No operation specified.\n"), stderr); argp_help (&argp, stderr, ARGP_HELP_SEE, program_invocation_short_name); exit (EXIT_FAILURE); } /* We only use this for checking the number of arguments, we don't actually want to consume them. */ FALLTHROUGH; default: return ARGP_ERR_UNKNOWN; } return 0; } /* Open the file and determine the type. */ static int process_file (const char *fname, bool more_than_one) { /* Open the file. */ int fd = open (fname, O_RDONLY); if (fd == -1) { error (0, errno, _("cannot open %s"), fname); return 1; } /* Now get the ELF descriptor. */ Elf *elf = elf_begin (fd, ELF_C_READ_MMAP, NULL); if (elf != NULL) { if (elf_kind (elf) == ELF_K_ELF) { int result = handle_elf (elf, more_than_one ? "" : NULL, fname, NULL); if (elf_end (elf) != 0) INTERNAL_ERROR (fname); if (close (fd) != 0) error_exit (errno, _("while close `%s'"), fname); return result; } else if (elf_kind (elf) == ELF_K_AR) { int result = handle_ar (fd, elf, NULL, fname, NULL); if (elf_end (elf) != 0) INTERNAL_ERROR (fname); if (close (fd) != 0) error_exit (errno, _("while close `%s'"), fname); return result; } /* We cannot handle this type. Close the descriptor anyway. */ if (elf_end (elf) != 0) INTERNAL_ERROR (fname); } error (0, 0, _("%s: File format not recognized"), fname); return 1; } static int handle_ar (int fd, Elf *elf, const char *prefix, const char *fname, const char *suffix) { size_t fname_len = strlen (fname) + 1; size_t prefix_len = prefix != NULL ? strlen (prefix) : 0; char new_prefix[prefix_len + fname_len + 2]; size_t suffix_len = suffix != NULL ? strlen (suffix) : 0; char new_suffix[suffix_len + 2]; Elf *subelf; Elf_Cmd cmd = ELF_C_READ_MMAP; int result = 0; char *cp = new_prefix; if (prefix != NULL) cp = stpcpy (cp, prefix); cp = stpcpy (cp, fname); stpcpy (cp, "["); cp = new_suffix; if (suffix != NULL) cp = stpcpy (cp, suffix); stpcpy (cp, "]"); /* Process all the files contained in the archive. */ while ((subelf = elf_begin (fd, cmd, elf)) != NULL) { /* The the header for this element. */ Elf_Arhdr *arhdr = elf_getarhdr (subelf); /* Skip over the index entries. */ if (arhdr != NULL && strcmp (arhdr->ar_name, "/") != 0 && strcmp (arhdr->ar_name, "//") != 0) { if (elf_kind (subelf) == ELF_K_ELF) result |= handle_elf (subelf, new_prefix, arhdr->ar_name, new_suffix); else if (elf_kind (subelf) == ELF_K_AR) result |= handle_ar (fd, subelf, new_prefix, arhdr->ar_name, new_suffix); else { error (0, 0, _("%s%s%s: file format not recognized"), new_prefix, arhdr->ar_name, new_suffix); result = 1; } } /* Get next archive element. */ cmd = elf_next (subelf); if (elf_end (subelf) != 0) INTERNAL_ERROR (fname); } return result; } static void show_relocs_x (Ebl *ebl, GElf_Shdr *shdr, Elf_Data *symdata, Elf_Data *xndxdata, size_t symstrndx, size_t shstrndx, GElf_Addr r_offset, GElf_Xword r_info, GElf_Sxword r_addend) { int elfclass = gelf_getclass (ebl->elf); char buf[128]; printf ("%0*" PRIx64 " %-20s ", elfclass == ELFCLASS32 ? 8 : 16, r_offset, ebl_reloc_type_name (ebl, GELF_R_TYPE (r_info), buf, sizeof (buf))); Elf32_Word xndx; GElf_Sym symmem; GElf_Sym *sym = gelf_getsymshndx (symdata, xndxdata, GELF_R_SYM (r_info), &symmem, &xndx); if (sym == NULL) printf ("<%s %ld>", _("INVALID SYMBOL"), (long int) GELF_R_SYM (r_info)); else if (GELF_ST_TYPE (sym->st_info) != STT_SECTION) printf ("%s", elf_strptr (ebl->elf, symstrndx, sym->st_name)); else { GElf_Shdr destshdr_mem; GElf_Shdr *destshdr; destshdr = gelf_getshdr (elf_getscn (ebl->elf, sym->st_shndx == SHN_XINDEX ? xndx : sym->st_shndx), &destshdr_mem); if (shdr == NULL || destshdr == NULL) printf ("<%s %ld>", _("INVALID SECTION"), (long int) (sym->st_shndx == SHN_XINDEX ? xndx : sym->st_shndx)); else printf ("%s", elf_strptr (ebl->elf, shstrndx, destshdr->sh_name)); } if (r_addend != 0) { char sign = '+'; if (r_addend < 0) { sign = '-'; r_addend = -r_addend; } printf ("%c%#" PRIx64, sign, r_addend); } putchar ('\n'); } static void show_relocs_rel (Ebl *ebl, GElf_Shdr *shdr, Elf_Data *data, Elf_Data *symdata, Elf_Data *xndxdata, size_t symstrndx, size_t shstrndx) { size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_REL, 1, EV_CURRENT); int nentries = shdr->sh_size / sh_entsize; for (int cnt = 0; cnt < nentries; ++cnt) { GElf_Rel relmem; GElf_Rel *rel; rel = gelf_getrel (data, cnt, &relmem); if (rel != NULL) show_relocs_x (ebl, shdr, symdata, xndxdata, symstrndx, shstrndx, rel->r_offset, rel->r_info, 0); } } static void show_relocs_rela (Ebl *ebl, GElf_Shdr *shdr, Elf_Data *data, Elf_Data *symdata, Elf_Data *xndxdata, size_t symstrndx, size_t shstrndx) { size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_RELA, 1, EV_CURRENT); int nentries = shdr->sh_size / sh_entsize; for (int cnt = 0; cnt < nentries; ++cnt) { GElf_Rela relmem; GElf_Rela *rel; rel = gelf_getrela (data, cnt, &relmem); if (rel != NULL) show_relocs_x (ebl, shdr, symdata, xndxdata, symstrndx, shstrndx, rel->r_offset, rel->r_info, rel->r_addend); } } static bool section_match (Elf *elf, uint32_t scnndx, GElf_Shdr *shdr, size_t shstrndx) { if (section_list == NULL) return true; struct section_list *runp = section_list; const char *name = elf_strptr (elf, shstrndx, shdr->sh_name); do { if (runp->is_name) { if (name && strcmp (runp->name, name) == 0) return true; } else { if (runp->scnndx == scnndx) return true; } runp = runp->next; } while (runp != NULL); return false; } static int show_relocs (Ebl *ebl, const char *fname, uint32_t shstrndx) { int elfclass = gelf_getclass (ebl->elf); Elf_Scn *scn = NULL; while ((scn = elf_nextscn (ebl->elf, scn)) != NULL) { GElf_Shdr shdr_mem; GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); if (shdr == NULL) INTERNAL_ERROR (fname); if (shdr->sh_type == SHT_REL || shdr->sh_type == SHT_RELA) { if (! section_match (ebl->elf, elf_ndxscn (scn), shdr, shstrndx)) continue; GElf_Shdr destshdr_mem; GElf_Shdr *destshdr = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_info), &destshdr_mem); if (unlikely (destshdr == NULL)) continue; printf (_("\nRELOCATION RECORDS FOR [%s]:\n" "%-*s TYPE VALUE\n"), elf_strptr (ebl->elf, shstrndx, destshdr->sh_name), elfclass == ELFCLASS32 ? 8 : 16, _("OFFSET")); /* Get the data of the section. */ Elf_Data *data = elf_getdata (scn, NULL); if (data == NULL) continue; /* Get the symbol table information. */ Elf_Scn *symscn = elf_getscn (ebl->elf, shdr->sh_link); GElf_Shdr symshdr_mem; GElf_Shdr *symshdr = gelf_getshdr (symscn, &symshdr_mem); Elf_Data *symdata = elf_getdata (symscn, NULL); if (unlikely (symshdr == NULL || symdata == NULL)) continue; /* Search for the optional extended section index table. */ Elf_Data *xndxdata = NULL; Elf_Scn *xndxscn = NULL; while ((xndxscn = elf_nextscn (ebl->elf, xndxscn)) != NULL) { GElf_Shdr xndxshdr_mem; GElf_Shdr *xndxshdr; xndxshdr = gelf_getshdr (xndxscn, &xndxshdr_mem); if (xndxshdr != NULL && xndxshdr->sh_type == SHT_SYMTAB_SHNDX && xndxshdr->sh_link == elf_ndxscn (symscn)) { /* Found it. */ xndxdata = elf_getdata (xndxscn, NULL); break; } } if (shdr->sh_type == SHT_REL) show_relocs_rel (ebl, shdr, data, symdata, xndxdata, symshdr->sh_link, shstrndx); else show_relocs_rela (ebl, shdr, data, symdata, xndxdata, symshdr->sh_link, shstrndx); putchar ('\n'); } } return 0; } static int show_full_content (Ebl *ebl, const char *fname, uint32_t shstrndx) { Elf_Scn *scn = NULL; while ((scn = elf_nextscn (ebl->elf, scn)) != NULL) { GElf_Shdr shdr_mem; GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); if (shdr == NULL) INTERNAL_ERROR (fname); if (shdr->sh_type == SHT_PROGBITS && shdr->sh_size > 0) { if (! section_match (ebl->elf, elf_ndxscn (scn), shdr, shstrndx)) continue; printf (_("Contents of section %s:\n"), elf_strptr (ebl->elf, shstrndx, shdr->sh_name)); /* Get the data of the section. */ Elf_Data *data = elf_getdata (scn, NULL); if (data == NULL) continue; unsigned char *cp = data->d_buf; size_t cnt; for (cnt = 0; cnt + 16 < data->d_size; cp += 16, cnt += 16) { printf (" %04zx ", cnt); for (size_t inner = 0; inner < 16; inner += 4) printf ("%02hhx%02hhx%02hhx%02hhx ", cp[inner], cp[inner + 1], cp[inner + 2], cp[inner + 3]); fputc (' ', stdout); for (size_t inner = 0; inner < 16; ++inner) fputc (isascii (cp[inner]) && isprint (cp[inner]) ? cp[inner] : '.', stdout); fputc ('\n', stdout); } printf (" %04zx ", cnt); size_t remaining = data->d_size - cnt; size_t inner; for (inner = 0; inner + 4 <= remaining; inner += 4) printf ("%02hhx%02hhx%02hhx%02hhx ", cp[inner], cp[inner + 1], cp[inner + 2], cp[inner + 3]); for (; inner < remaining; ++inner) printf ("%02hhx", cp[inner]); for (inner = 2 * (16 - inner) + (16 - inner + 3) / 4 + 1; inner > 0; --inner) fputc (' ', stdout); for (inner = 0; inner < remaining; ++inner) fputc (isascii (cp[inner]) && isprint (cp[inner]) ? cp[inner] : '.', stdout); fputc ('\n', stdout); fputc ('\n', stdout); } } return 0; } struct disasm_info { GElf_Addr addr; const uint8_t *cur; const uint8_t *last_end; const char *address_color; const char *bytes_color; }; // XXX This is not the preferred output for all architectures. Needs // XXX customization, too. static int disasm_output (char *buf, size_t buflen, void *arg) { struct disasm_info *info = (struct disasm_info *) arg; if (info->address_color != NULL) printf ("%s%8" PRIx64 "%s: ", info->address_color, (uint64_t) info->addr, color_off); else printf ("%8" PRIx64 ": ", (uint64_t) info->addr); if (info->bytes_color != NULL) fputs (info->bytes_color, stdout); size_t cnt; for (cnt = 0; cnt < (size_t) MIN (info->cur - info->last_end, 8); ++cnt) printf (" %02" PRIx8, info->last_end[cnt]); if (info->bytes_color != NULL) fputs (color_off, stdout); printf ("%*s %.*s\n", (int) (8 - cnt) * 3 + 1, "", (int) buflen, buf); info->addr += cnt; /* We limit the number of bytes printed before the mnemonic to 8. Print the rest on a separate, following line. */ if (info->cur - info->last_end > 8) { if (info->address_color != NULL) printf ("%s%8" PRIx64 "%s: ", info->address_color, (uint64_t) info->addr, color_off); else printf ("%8" PRIx64 ": ", (uint64_t) info->addr); if (info->bytes_color != NULL) fputs (info->bytes_color, stdout); for (; cnt < (size_t) (info->cur - info->last_end); ++cnt) printf (" %02" PRIx8, info->last_end[cnt]); if (info->bytes_color != NULL) fputs (color_off, stdout); putchar ('\n'); info->addr += info->cur - info->last_end - 8; } info->last_end = info->cur; return 0; } static int show_disasm (Ebl *ebl, const char *fname, uint32_t shstrndx) { DisasmCtx_t *ctx = disasm_begin (ebl, ebl->elf, NULL /* XXX TODO */); if (ctx == NULL) error_exit (0, _("cannot disassemble")); Elf_Scn *scn = NULL; while ((scn = elf_nextscn (ebl->elf, scn)) != NULL) { GElf_Shdr shdr_mem; GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); if (shdr == NULL) INTERNAL_ERROR (fname); if (shdr->sh_type == SHT_PROGBITS && shdr->sh_size > 0 && (shdr->sh_flags & SHF_EXECINSTR) != 0) { if (! section_match (ebl->elf, elf_ndxscn (scn), shdr, shstrndx)) continue; Elf_Data *data = elf_getdata (scn, NULL); if (data == NULL) continue; printf ("Disassembly of section %s:\n\n", elf_strptr (ebl->elf, shstrndx, shdr->sh_name)); struct disasm_info info; info.addr = shdr->sh_addr; info.last_end = info.cur = data->d_buf; char *fmt; if (color_mode) { info.address_color = color_address; info.bytes_color = color_bytes; fmt = xasprintf ("%s%%7m %s%%.1o,%s%%.2o,%s%%.3o,,%s%%.4o%s%%.5o%%34a %s%%l", color_mnemonic ?: "", color_operand1 ?: "", color_operand2 ?: "", color_operand3 ?: "", color_operand4 ?: "", color_operand5 ?: "", color_label ?: ""); } else { info.address_color = info.bytes_color = NULL; fmt = "%7m %.1o,%.2o,%.3o,%.4o,%.5o%34a %l"; } disasm_cb (ctx, &info.cur, info.cur + data->d_size, info.addr, fmt, disasm_output, &info, NULL /* XXX */); if (color_mode) free (fmt); } } (void) disasm_end (ctx); return 0; } static int handle_elf (Elf *elf, const char *prefix, const char *fname, const char *suffix) { /* Get the backend for this object file type. */ Ebl *ebl = ebl_openbackend (elf); if (ebl == NULL) error_exit (0, _("cannot create backend for elf file")); printf ("%s: elf%d-%s\n\n", fname, gelf_getclass (elf) == ELFCLASS32 ? 32 : 64, ebl_backend_name (ebl)); /* Create the full name of the file. */ size_t prefix_len = prefix == NULL ? 0 : strlen (prefix); size_t suffix_len = suffix == NULL ? 0 : strlen (suffix); size_t fname_len = strlen (fname) + 1; char fullname[prefix_len + 1 + fname_len + suffix_len]; char *cp = fullname; if (prefix != NULL) cp = mempcpy (cp, prefix, prefix_len); cp = mempcpy (cp, fname, fname_len); if (suffix != NULL) memcpy (cp - 1, suffix, suffix_len + 1); /* Get the section header string table index. */ size_t shstrndx; if (elf_getshdrstrndx (ebl->elf, &shstrndx) < 0) error_exit (0, _("cannot get section header string table index")); int result = 0; if (print_disasm) result = show_disasm (ebl, fullname, shstrndx); if (print_relocs && !print_disasm) result = show_relocs (ebl, fullname, shstrndx); if (print_full_content) result = show_full_content (ebl, fullname, shstrndx); /* Close the ELF backend library descriptor. */ ebl_closebackend (ebl); return result; } #include "debugpred.h"