The Android Open Source Project | 441f72d | 2009-03-03 19:29:28 -0800 | [diff] [blame] | 1 | /* Compute simple checksum from permanent parts of the ELF file. |
| 2 | Copyright (C) 2002, 2003, 2004 Red Hat, Inc. |
| 3 | Written by Ulrich Drepper <drepper@redhat.com>, 2002. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation, version 2. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program; if not, write to the Free Software Foundation, |
| 16 | Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 17 | |
| 18 | #ifdef HAVE_CONFIG_H |
| 19 | # include <config.h> |
| 20 | #endif |
| 21 | |
| 22 | #include <assert.h> |
The Android Open Source Project | 441f72d | 2009-03-03 19:29:28 -0800 | [diff] [blame] | 23 | #include <stdbool.h> |
| 24 | #include <stddef.h> |
| 25 | #include <string.h> |
| 26 | |
| 27 | #include "gelf.h" |
| 28 | #include "libelfP.h" |
| 29 | #include "elf-knowledge.h" |
| 30 | |
| 31 | #ifndef LIBELFBITS |
| 32 | # define LIBELFBITS 32 |
| 33 | #endif |
| 34 | |
| 35 | |
| 36 | /* The SECTION_STRIP_P macro wants to call into libebl which we cannot |
| 37 | do and do not have to do here. Provide a dummy replacement. */ |
| 38 | #define ebl_debugscn_p(ebl, name) true |
| 39 | |
| 40 | |
| 41 | #define process_block(crc, data) \ |
| 42 | __libelf_crc32 (crc, data->d_buf, data->d_size) |
| 43 | |
| 44 | |
| 45 | long int |
| 46 | elfw2(LIBELFBITS,checksum) (elf) |
| 47 | Elf *elf; |
| 48 | { |
| 49 | size_t shstrndx; |
| 50 | Elf_Scn *scn; |
| 51 | long int result = 0; |
| 52 | unsigned char *ident; |
| 53 | bool same_byte_order; |
| 54 | |
| 55 | if (elf == NULL) |
| 56 | return -1l; |
| 57 | |
| 58 | /* Find the section header string table. */ |
| 59 | if (INTUSE(elf_getshstrndx) (elf, &shstrndx) < 0) |
| 60 | { |
| 61 | /* This can only happen if the ELF handle is not for real. */ |
| 62 | __libelf_seterrno (ELF_E_INVALID_HANDLE); |
| 63 | return -1l; |
| 64 | } |
| 65 | |
| 66 | /* Determine whether the byte order of the file and that of the host |
| 67 | is the same. */ |
| 68 | ident = elf->state.ELFW(elf,LIBELFBITS).ehdr->e_ident; |
| 69 | same_byte_order = ((ident[EI_DATA] == ELFDATA2LSB |
| 70 | && __BYTE_ORDER == __LITTLE_ENDIAN) |
| 71 | || (ident[EI_DATA] == ELFDATA2MSB |
| 72 | && __BYTE_ORDER == __BIG_ENDIAN)); |
| 73 | |
| 74 | /* Iterate over all sections to find those which are not strippable. */ |
| 75 | scn = NULL; |
| 76 | while ((scn = INTUSE(elf_nextscn) (elf, scn)) != NULL) |
| 77 | { |
| 78 | GElf_Shdr shdr_mem; |
| 79 | GElf_Shdr *shdr; |
| 80 | Elf_Data *data; |
| 81 | |
| 82 | /* Get the section header. */ |
| 83 | shdr = INTUSE(gelf_getshdr) (scn, &shdr_mem); |
| 84 | if (shdr == NULL) |
| 85 | { |
| 86 | __libelf_seterrno (ELF_E_INVALID_SECTION_HEADER); |
| 87 | return -1l; |
| 88 | } |
| 89 | |
| 90 | if (SECTION_STRIP_P (NULL, NULL, NULL, shdr, |
| 91 | elf_strptr (elf, shstrndx, shdr->sh_name), |
| 92 | true, false)) |
| 93 | /* The section can be stripped. Don't use it. */ |
| 94 | continue; |
| 95 | |
| 96 | /* To compute the checksum we need to get to the data. For |
| 97 | repeatable results we must use the external format. The data |
| 98 | we get with 'elf'getdata' might be changed for endianess |
| 99 | reasons. Therefore we use 'elf_rawdata' if possible. But |
| 100 | this function can fail if the data was constructed by the |
| 101 | program. In this case we have to use 'elf_getdata' and |
| 102 | eventually convert the data to the external format. */ |
| 103 | data = INTUSE(elf_rawdata) (scn, NULL); |
| 104 | if (data != NULL) |
| 105 | { |
| 106 | /* The raw data is available. */ |
| 107 | result = process_block (result, data); |
| 108 | |
| 109 | /* Maybe the user added more data. These blocks cannot be |
| 110 | read using 'elf_rawdata'. Simply proceed with looking |
| 111 | for more data block with 'elf_getdata'. */ |
| 112 | } |
| 113 | |
| 114 | /* Iterate through the list of data blocks. */ |
| 115 | while ((data = INTUSE(elf_getdata) (scn, data)) != NULL) |
| 116 | /* If the file byte order is the same as the host byte order |
| 117 | process the buffer directly. If the data is just a stream |
| 118 | of bytes which the library will not convert we can use it |
| 119 | as well. */ |
| 120 | if (likely (same_byte_order) || data->d_type == ELF_T_BYTE) |
| 121 | result = process_block (result, data); |
| 122 | else |
| 123 | { |
| 124 | /* Convert the data to file byte order. */ |
| 125 | if (INTUSE(elfw2(LIBELFBITS,xlatetof)) (data, data, ident[EI_DATA]) |
| 126 | == NULL) |
| 127 | return -1l; |
| 128 | |
| 129 | result = process_block (result, data); |
| 130 | |
| 131 | /* And convert it back. */ |
| 132 | if (INTUSE(elfw2(LIBELFBITS,xlatetom)) (data, data, ident[EI_DATA]) |
| 133 | == NULL) |
| 134 | return -1l; |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | return result; |
| 139 | } |
| 140 | INTDEF(elfw2(LIBELFBITS,checksum)) |