| /* Compare relevant content of two ELF files. |
| Copyright (C) 2005 Red Hat, Inc. |
| Written by Ulrich Drepper <drepper@redhat.com>, 2005. |
| |
| This program is Open Source software; you can redistribute it and/or |
| modify it under the terms of the Open Software License version 1.0 as |
| published by the Open Source Initiative. |
| |
| You should have received a copy of the Open Software License along |
| with this program; if not, you may obtain a copy of the Open Software |
| License version 1.0 from http://www.opensource.org/licenses/osl.php or |
| by writing the Open Source Initiative c/o Lawrence Rosen, Esq., |
| 3001 King Ranch Road, Ukiah, CA 95482. */ |
| |
| #ifdef HAVE_CONFIG_H |
| # include <config.h> |
| #endif |
| |
| #include <argp.h> |
| #include <assert.h> |
| #include <errno.h> |
| #include <error.h> |
| #include <fcntl.h> |
| #include <locale.h> |
| #include <libintl.h> |
| #include <stdbool.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include "../libelf/elf-knowledge.h" |
| #include "../libebl/libeblP.h" |
| |
| |
| /* Prototypes of local functions. */ |
| static Elf *open_file (const char *fname, int *fdp, Ebl **eblp); |
| static bool search_for_copy_reloc (Ebl *ebl, size_t scnndx, int symndx); |
| static int regioncompare (const void *p1, const void *p2); |
| |
| |
| /* Name and version of program. */ |
| static void print_version (FILE *stream, struct argp_state *state); |
| void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version; |
| |
| /* Bug report address. */ |
| const char *argp_program_bug_address = PACKAGE_BUGREPORT; |
| |
| /* Values for the parameters which have no short form. */ |
| #define OPT_GAPS 0x100 |
| |
| /* Definitions of arguments for argp functions. */ |
| static const struct argp_option options[] = |
| { |
| { NULL, 0, NULL, 0, N_("Control options:"), 0 }, |
| { "gaps", OPT_GAPS, "ACTION", 0, N_("Control treatment of gaps in loadable segments [ignore|match] (default: ignore)"), 0 }, |
| { "quiet", 'q', NULL, 0, N_("Output nothing; yield exit status only"), 0 }, |
| |
| { NULL, 0, NULL, 0, N_("Miscellaneous:"), 0 }, |
| { NULL, 0, NULL, 0, NULL, 0 } |
| }; |
| |
| /* Short description of program. */ |
| static const char doc[] = N_("\ |
| Compare relevant parts of two ELF files for equality."); |
| |
| /* Strings for arguments in help texts. */ |
| static const char args_doc[] = N_("FILE1 FILE2"); |
| |
| /* Prototype for option handler. */ |
| static error_t parse_opt (int key, char *arg, struct argp_state *state); |
| |
| /* Data structure to communicate with argp functions. */ |
| static struct argp argp = |
| { |
| options, parse_opt, args_doc, doc, NULL, NULL, NULL |
| }; |
| |
| |
| /* How to treat gaps in loadable segments. */ |
| static enum |
| { |
| gaps_ignore = 0, |
| gaps_match |
| } |
| gaps; |
| |
| /* Structure to hold information about used regions. */ |
| struct region |
| { |
| GElf_Addr from; |
| GElf_Addr to; |
| struct region *next; |
| }; |
| |
| /* Nonzero if only exit status is wanted. */ |
| static bool quiet; |
| |
| |
| int |
| main (int argc, char *argv[]) |
| { |
| /* Set locale. */ |
| (void) setlocale (LC_ALL, ""); |
| |
| /* Make sure the message catalog can be found. */ |
| (void) bindtextdomain (PACKAGE, LOCALEDIR); |
| |
| /* Initialize the message catalog. */ |
| (void) textdomain (PACKAGE); |
| |
| /* Parse and process arguments. */ |
| int remaining; |
| (void) argp_parse (&argp, argc, argv, 0, &remaining, NULL); |
| |
| /* We expect exactly two non-option parameters. */ |
| if (remaining + 2 != argc) |
| { |
| fputs (gettext ("Invalid number of parameters.\n"), stderr); |
| argp_help (&argp, stderr, ARGP_HELP_SEE, program_invocation_short_name); |
| exit (1); |
| } |
| |
| /* Comparing the files is done in two phases: |
| 1. compare all sections. Sections which are irrelevant (i.e., if |
| strip would remove them) are ignored. Some section types are |
| handled special. |
| 2. all parts of the loadable segments which are not parts of any |
| section is compared according to the rules of the --gaps option. |
| */ |
| int result = 0; |
| elf_version (EV_CURRENT); |
| |
| const char *const fname1 = argv[remaining]; |
| int fd1; |
| Ebl *ebl1; |
| Elf *elf1 = open_file (fname1, &fd1, &ebl1); |
| |
| const char *const fname2 = argv[remaining + 1]; |
| int fd2; |
| Ebl *ebl2; |
| Elf *elf2 = open_file (fname2, &fd2, &ebl2); |
| |
| GElf_Ehdr ehdr1_mem; |
| GElf_Ehdr *ehdr1 = gelf_getehdr (elf1, &ehdr1_mem); |
| if (ehdr1 == NULL) |
| error (EXIT_FAILURE, 0, gettext ("cannot get ELF header of \"%s\": %s"), |
| fname1, elf_errmsg (-1)); |
| GElf_Ehdr ehdr2_mem; |
| GElf_Ehdr *ehdr2 = gelf_getehdr (elf2, &ehdr2_mem); |
| if (ehdr2 == NULL) |
| error (EXIT_FAILURE, 0, gettext ("cannot get ELF header of \"%s\": %s"), |
| fname2, elf_errmsg (-1)); |
| |
| /* Compare the ELF headers. */ |
| if (memcmp (ehdr1->e_ident, ehdr2->e_ident, EI_NIDENT) != 0 |
| || ehdr1->e_type != ehdr2->e_type |
| || ehdr1->e_machine != ehdr2->e_machine |
| || ehdr1->e_version != ehdr2->e_version |
| || ehdr1->e_entry != ehdr2->e_entry |
| || ehdr1->e_phoff != ehdr2->e_phoff |
| || ehdr1->e_flags != ehdr2->e_flags |
| || ehdr1->e_ehsize != ehdr2->e_ehsize |
| || ehdr1->e_phentsize != ehdr2->e_phentsize |
| || ehdr1->e_phnum != ehdr2->e_phnum |
| || ehdr1->e_shentsize != ehdr2->e_shentsize |
| || ehdr1->e_shnum != ehdr2->e_shnum |
| || ehdr1->e_shstrndx != ehdr2->e_shstrndx) |
| { |
| if (! quiet) |
| error (0, 0, gettext ("%s %s diff: ELF header"), fname1, fname2); |
| result = 1; |
| goto out; |
| } |
| |
| /* Iterate over all sections. We expect the sections in the two |
| files to match exactly. */ |
| Elf_Scn *scn1 = NULL; |
| Elf_Scn *scn2 = NULL; |
| struct region *regions = NULL; |
| size_t nregions = 0; |
| while (1) |
| { |
| GElf_Shdr shdr1_mem; |
| GElf_Shdr *shdr1; |
| const char *sname1 = NULL; |
| do |
| { |
| scn1 = elf_nextscn (elf1, scn1); |
| shdr1 = gelf_getshdr (scn1, &shdr1_mem); |
| if (shdr1 != NULL) |
| sname1 = elf_strptr (elf1, ehdr1->e_shstrndx, shdr1->sh_name); |
| } |
| while (scn1 != NULL |
| && ebl_section_strip_p (ebl1, ehdr1, shdr1, sname1, true, false)); |
| |
| GElf_Shdr shdr2_mem; |
| GElf_Shdr *shdr2; |
| const char *sname2 = NULL; |
| do |
| { |
| scn2 = elf_nextscn (elf2, scn2); |
| shdr2 = gelf_getshdr (scn2, &shdr2_mem); |
| if (shdr2 != NULL) |
| sname2 = elf_strptr (elf2, ehdr2->e_shstrndx, shdr2->sh_name); |
| } |
| while (scn2 != NULL |
| && ebl_section_strip_p (ebl2, ehdr2, shdr2, sname2, true, false)); |
| |
| if (scn1 == NULL || scn2 == NULL) |
| break; |
| |
| if (gaps != gaps_ignore && (shdr1->sh_flags & SHF_ALLOC) != 0) |
| { |
| struct region *newp = (struct region *) alloca (sizeof (*newp)); |
| newp->from = shdr1->sh_offset; |
| newp->to = shdr1->sh_offset + shdr1->sh_size; |
| newp->next = regions; |
| regions = newp; |
| |
| ++nregions; |
| } |
| |
| /* Compare the headers. We allow the name to be at a different |
| location. */ |
| if (strcmp (sname1, sname2) != 0) |
| { |
| header_mismatch: |
| error (0, 0, gettext ("%s %s differ: section header"), |
| fname1, fname2); |
| result = 1; |
| goto out; |
| } |
| |
| /* We ignore certain sections. */ |
| if (strcmp (sname1, ".gnu_debuglink") == 0 |
| || strcmp (sname1, ".gnu.prelink_undo") == 0) |
| continue; |
| |
| if (shdr1->sh_type != shdr2->sh_type |
| // XXX Any flags which should be ignored? |
| || shdr1->sh_flags != shdr2->sh_flags |
| || shdr1->sh_addr != shdr2->sh_addr |
| || shdr1->sh_offset != shdr2->sh_offset |
| || shdr1->sh_size != shdr2->sh_size |
| || shdr1->sh_link != shdr2->sh_link |
| || shdr1->sh_info != shdr2->sh_info |
| || shdr1->sh_addralign != shdr2->sh_addralign |
| || shdr1->sh_entsize != shdr2->sh_entsize) |
| goto header_mismatch; |
| |
| Elf_Data *data1 = elf_getdata (scn1, NULL); |
| if (data1 == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get content of section %zu in \"%s\": %s"), |
| elf_ndxscn (scn1), fname1, elf_errmsg (-1)); |
| |
| Elf_Data *data2 = elf_getdata (scn2, NULL); |
| if (data2 == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get content of section %zu in \"%s\": %s"), |
| elf_ndxscn (scn2), fname2, elf_errmsg (-1)); |
| |
| switch (shdr1->sh_type) |
| { |
| case SHT_DYNSYM: |
| case SHT_SYMTAB: |
| /* Iterate over the symbol table. We ignore the st_size |
| value of undefined symbols. */ |
| for (int ndx = 0; ndx < (int) (shdr1->sh_size / shdr1->sh_entsize); |
| ++ndx) |
| { |
| GElf_Sym sym1_mem; |
| GElf_Sym *sym1 = gelf_getsym (data1, ndx, &sym1_mem); |
| if (sym1 == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get symbol in \"%s\": %s"), |
| fname1, elf_errmsg (-1)); |
| GElf_Sym sym2_mem; |
| GElf_Sym *sym2 = gelf_getsym (data2, ndx, &sym2_mem); |
| if (sym2 == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get symbol in \"%s\": %s"), |
| fname2, elf_errmsg (-1)); |
| |
| const char *name1 = elf_strptr (elf1, shdr1->sh_link, |
| sym1->st_name); |
| const char *name2 = elf_strptr (elf2, shdr2->sh_link, |
| sym2->st_name); |
| if (strcmp (name1, name2) != 0 |
| || sym1->st_value != sym2->st_value |
| || (sym1->st_size != sym2->st_size |
| && sym1->st_shndx != SHN_UNDEF) |
| || sym1->st_info != sym2->st_info |
| || sym1->st_other != sym2->st_other |
| || sym1->st_shndx != sym1->st_shndx) |
| { |
| // XXX Do we want to allow reordered symbol tables? |
| symtab_mismatch: |
| if (! quiet) |
| { |
| if (elf_ndxscn (scn1) == elf_ndxscn (scn2)) |
| error (0, 0, |
| gettext ("%s %s differ: symbol table [%zu]"), |
| fname1, fname2, elf_ndxscn (scn1)); |
| else |
| error (0, 0, gettext ("\ |
| %s %s differ: symbol table [%zu,%zu]"), |
| fname1, fname2, elf_ndxscn (scn1), |
| elf_ndxscn (scn2)); |
| } |
| result = 1; |
| goto out; |
| } |
| |
| if (sym1->st_shndx == SHN_UNDEF |
| && sym1->st_size != sym2->st_size) |
| { |
| /* The size of the symbol in the object defining it |
| might have changed. That is OK unless the symbol |
| is used in a copy relocation. Look over the |
| sections in both files and determine which |
| relocation section uses this symbol table |
| section. Then look through the relocations to |
| see whether any copy relocation references this |
| symbol. */ |
| if (search_for_copy_reloc (ebl1, elf_ndxscn (scn1), ndx) |
| || search_for_copy_reloc (ebl2, elf_ndxscn (scn2), ndx)) |
| goto symtab_mismatch; |
| } |
| } |
| break; |
| |
| default: |
| /* Compare the section content byte for byte. */ |
| assert (shdr1->sh_type == SHT_NOBITS |
| || (data1->d_buf != NULL || data1->d_size == 0)); |
| assert (shdr2->sh_type == SHT_NOBITS |
| || (data2->d_buf != NULL || data1->d_size == 0)); |
| |
| if (data1->d_size != data2->d_size |
| || (shdr1->sh_type != SHT_NOBITS |
| && memcmp (data1->d_buf, data2->d_buf, data1->d_size) != 0)) |
| { |
| if (! quiet) |
| { |
| if (elf_ndxscn (scn1) == elf_ndxscn (scn2)) |
| error (0, 0, gettext ("\ |
| %s %s differ: section [%zu] '%s' content"), |
| fname1, fname2, elf_ndxscn (scn1), sname1); |
| else |
| if (elf_ndxscn (scn1) == elf_ndxscn (scn2)) |
| error (0, 0, gettext ("\ |
| %s %s differ: section [%zu,%zu] '%s' content"), |
| fname1, fname2, elf_ndxscn (scn1), |
| elf_ndxscn (scn2), sname1); |
| } |
| result = 1; |
| goto out; |
| } |
| break; |
| } |
| } |
| |
| if (scn1 != scn2) |
| { |
| if (! quiet) |
| error (0, 0, |
| gettext ("%s %s differ: unequal amount of important sections"), |
| fname1, fname2); |
| result = 1; |
| goto out; |
| } |
| |
| /* We we look at gaps, create artificial ones for the parts of the |
| program which we are not in sections. */ |
| struct region ehdr_region; |
| struct region phdr_region; |
| if (gaps != gaps_ignore) |
| { |
| ehdr_region.from = 0; |
| ehdr_region.to = ehdr1->e_ehsize; |
| ehdr_region.next = &phdr_region; |
| |
| phdr_region.from = ehdr1->e_phoff; |
| phdr_region.to = ehdr1->e_phoff + ehdr1->e_phnum * ehdr1->e_phentsize; |
| phdr_region.next = regions; |
| |
| regions = &ehdr_region; |
| nregions += 2; |
| } |
| |
| /* If we need to look at the gaps we need access to the file data. */ |
| char *raw1 = NULL; |
| size_t size1 = 0; |
| char *raw2 = NULL; |
| size_t size2 = 0; |
| struct region *regionsarr = alloca (nregions * sizeof (struct region)); |
| if (gaps != gaps_ignore) |
| { |
| raw1 = elf_rawfile (elf1, &size1); |
| if (raw1 == NULL ) |
| error (EXIT_FAILURE, 0, gettext ("cannot load data of \"%s\": %s"), |
| fname1, elf_errmsg (-1)); |
| |
| raw2 = elf_rawfile (elf2, &size2); |
| if (raw2 == NULL ) |
| error (EXIT_FAILURE, 0, gettext ("cannot load data of \"%s\": %s"), |
| fname2, elf_errmsg (-1)); |
| |
| for (size_t cnt = 0; cnt < nregions; ++cnt) |
| { |
| regionsarr[cnt] = *regions; |
| regions = regions->next; |
| } |
| |
| qsort (regionsarr, nregions, sizeof (regionsarr[0]), regioncompare); |
| } |
| |
| /* Compare the program header tables. */ |
| for (int ndx = 0; ndx < ehdr1->e_phnum; ++ndx) |
| { |
| GElf_Phdr phdr1_mem; |
| GElf_Phdr *phdr1 = gelf_getphdr (elf1, ndx, &phdr1_mem); |
| if (ehdr1 == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get program header entry %d of \"%s\": %s"), |
| ndx, fname1, elf_errmsg (-1)); |
| GElf_Phdr phdr2_mem; |
| GElf_Phdr *phdr2 = gelf_getphdr (elf2, ndx, &phdr2_mem); |
| if (ehdr2 == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get program header entry %d of \"%s\": %s"), |
| ndx, fname2, elf_errmsg (-1)); |
| |
| if (memcmp (phdr1, phdr2, sizeof (GElf_Phdr)) != 0) |
| { |
| if (! quiet) |
| error (0, 0, gettext ("%s %s differ: program header %d"), |
| fname1, fname2, ndx); |
| result = 1; |
| goto out; |
| } |
| |
| if (gaps != gaps_ignore && phdr1->p_type == PT_LOAD) |
| { |
| size_t cnt = 0; |
| while (cnt < nregions && regionsarr[cnt].to < phdr1->p_offset) |
| ++cnt; |
| |
| GElf_Off last = phdr1->p_offset; |
| GElf_Off end = phdr1->p_offset + phdr1->p_filesz; |
| while (cnt < nregions && regionsarr[cnt].from < end) |
| { |
| if (last < regionsarr[cnt].from) |
| { |
| /* Compare the [LAST,FROM) region. */ |
| assert (gaps == gaps_match); |
| if (memcmp (raw1 + last, raw2 + last, |
| regionsarr[cnt].from - last) != 0) |
| { |
| gapmismatch: |
| if (!quiet) |
| error (0, 0, gettext ("%s %s differ: gap"), |
| fname1, fname2); |
| result = 1; |
| goto out; |
| } |
| |
| } |
| last = regionsarr[cnt].to; |
| ++cnt; |
| } |
| |
| if (cnt == nregions && last < end) |
| goto gapmismatch; |
| } |
| } |
| |
| out: |
| elf_end (elf1); |
| elf_end (elf2); |
| close (fd1); |
| close (fd2); |
| |
| return result; |
| } |
| |
| |
| /* Print the version information. */ |
| static void |
| print_version (FILE *stream, struct argp_state *state __attribute__ ((unused))) |
| { |
| fprintf (stream, "elfcmp (%s) %s\n", PACKAGE_NAME, VERSION); |
| fprintf (stream, gettext ("\ |
| Copyright (C) %s Red Hat, Inc.\n\ |
| This is free software; see the source for copying conditions. There is NO\n\ |
| warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\ |
| "), "2005"); |
| fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper"); |
| } |
| |
| |
| /* Handle program arguments. */ |
| static error_t |
| parse_opt (int key, char *arg, |
| struct argp_state *state __attribute__ ((unused))) |
| { |
| switch (key) |
| { |
| case 'q': |
| quiet = true; |
| break; |
| |
| case OPT_GAPS: |
| if (strcasecmp (arg, "ignore") == 0) |
| gaps = gaps_ignore; |
| else if (strcasecmp (arg, "match") == 0) |
| gaps = gaps_match; |
| else |
| { |
| fprintf (stderr, |
| gettext ("Invalid value \"%s\" for --gaps parameter."), |
| arg); |
| argp_help (&argp, stderr, ARGP_HELP_SEE, |
| program_invocation_short_name); |
| exit (1); |
| } |
| break; |
| |
| default: |
| return ARGP_ERR_UNKNOWN; |
| } |
| return 0; |
| } |
| |
| |
| static Elf * |
| open_file (const char *fname, int *fdp, Ebl **eblp) |
| { |
| int fd = open (fname, O_RDONLY); |
| if (unlikely (fd == -1)) |
| error (EXIT_FAILURE, errno, gettext ("cannot open \"%s\""), fname); |
| Elf *elf = elf_begin (fd, ELF_C_READ_MMAP, NULL); |
| if (elf == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot create ELF descriptor for \"%s\": %s"), |
| fname, elf_errmsg (-1)); |
| Ebl *ebl = ebl_openbackend (elf); |
| if (ebl == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot create EBL descriptor for \"%s\""), fname); |
| |
| *fdp = fd; |
| *eblp = ebl; |
| return elf; |
| } |
| |
| |
| static bool |
| search_for_copy_reloc (Ebl *ebl, size_t scnndx, int symndx) |
| { |
| 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) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get section header of section %zu: %s"), |
| elf_ndxscn (scn), elf_errmsg (-1)); |
| |
| if ((shdr->sh_type != SHT_REL && shdr->sh_type != SHT_RELA) |
| || shdr->sh_link != scnndx) |
| continue; |
| |
| Elf_Data *data = elf_getdata (scn, NULL); |
| if (data == NULL) |
| error (EXIT_FAILURE, 0, |
| gettext ("cannot get content of section %zu: %s"), |
| elf_ndxscn (scn), elf_errmsg (-1)); |
| |
| if (shdr->sh_type == SHT_REL) |
| for (int ndx = 0; ndx < (int) (shdr->sh_size / shdr->sh_entsize); |
| ++ndx) |
| { |
| GElf_Rel rel_mem; |
| GElf_Rel *rel = gelf_getrel (data, ndx, &rel_mem); |
| if (rel == NULL) |
| error (EXIT_FAILURE, 0, gettext ("cannot get relocation: %s"), |
| elf_errmsg (-1)); |
| |
| if ((int) GELF_R_SYM (rel->r_info) == symndx |
| && ebl_copy_reloc_p (ebl, GELF_R_TYPE (rel->r_info))) |
| return true; |
| } |
| else |
| for (int ndx = 0; ndx < (int) (shdr->sh_size / shdr->sh_entsize); |
| ++ndx) |
| { |
| GElf_Rela rela_mem; |
| GElf_Rela *rela = gelf_getrela (data, ndx, &rela_mem); |
| if (rela == NULL) |
| error (EXIT_FAILURE, 0, gettext ("cannot get relocation: %s"), |
| elf_errmsg (-1)); |
| |
| if ((int) GELF_R_SYM (rela->r_info) == symndx |
| && ebl_copy_reloc_p (ebl, GELF_R_TYPE (rela->r_info))) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| |
| static int |
| regioncompare (const void *p1, const void *p2) |
| { |
| const struct region *r1 = (const struct region *) p1; |
| const struct region *r2 = (const struct region *) p2; |
| |
| if (r1->from < r2->from) |
| return -1; |
| return 1; |
| } |