1 /* Update data structures for changes and write them out. 2 Copyright (C) 1999, 2000, 2001, 2002, 2004, 2005, 2006 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Contributed by Ulrich Drepper <drepper (at) redhat.com>, 1999. 5 6 Red Hat elfutils is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by the 8 Free Software Foundation; version 2 of the License. 9 10 Red Hat elfutils is distributed in the hope that it will be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 General Public License for more details. 14 15 You should have received a copy of the GNU General Public License along 16 with Red Hat elfutils; if not, write to the Free Software Foundation, 17 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 18 19 In addition, as a special exception, Red Hat, Inc. gives You the 20 additional right to link the code of Red Hat elfutils with code licensed 21 under any Open Source Initiative certified open source license 22 (http://www.opensource.org/licenses/index.php) which requires the 23 distribution of source code with any binary distribution and to 24 distribute linked combinations of the two. Non-GPL Code permitted under 25 this exception must only link to the code of Red Hat elfutils through 26 those well defined interfaces identified in the file named EXCEPTION 27 found in the source code files (the "Approved Interfaces"). The files 28 of Non-GPL Code may instantiate templates or use macros or inline 29 functions from the Approved Interfaces without causing the resulting 30 work to be covered by the GNU General Public License. Only Red Hat, 31 Inc. may make changes or additions to the list of Approved Interfaces. 32 Red Hat's grant of this exception is conditioned upon your not adding 33 any new exceptions. If you wish to add a new Approved Interface or 34 exception, please contact Red Hat. You must obey the GNU General Public 35 License in all respects for all of the Red Hat elfutils code and other 36 code used in conjunction with Red Hat elfutils except the Non-GPL Code 37 covered by this exception. If you modify this file, you may extend this 38 exception to your version of the file, but you are not obligated to do 39 so. If you do not wish to provide this exception without modification, 40 you must delete this exception statement from your version and license 41 this file solely under the GPL without exception. 42 43 Red Hat elfutils is an included package of the Open Invention Network. 44 An included package of the Open Invention Network is a package for which 45 Open Invention Network licensees cross-license their patents. No patent 46 license is granted, either expressly or impliedly, by designation as an 47 included package. Should you wish to participate in the Open Invention 48 Network licensing program, please visit www.openinventionnetwork.com 49 <http://www.openinventionnetwork.com>. */ 50 51 #ifdef HAVE_CONFIG_H 52 # include <config.h> 53 #endif 54 55 #include <libelf.h> 56 #include <unistd.h> 57 #include <sys/mman.h> 58 #include <sys/stat.h> 59 60 #include "libelfP.h" 61 62 63 static off_t 64 write_file (Elf *elf, off_t size, int change_bo, size_t shnum) 65 { 66 int class = elf->class; 67 68 /* Check the mode bits now, before modification might change them. */ 69 struct stat st; 70 if (unlikely (fstat (elf->fildes, &st) != 0)) 71 { 72 __libelf_seterrno (ELF_E_WRITE_ERROR); 73 return -1; 74 } 75 76 /* Adjust the size in any case. We do this even if we use `write'. 77 We cannot do this if this file is in an archive. We also don't 78 do it *now* if we are shortening the file since this would 79 prevent programs to use the data of the file in generating the 80 new file. We truncate the file later in this case. */ 81 if (elf->parent == NULL 82 && (elf->maximum_size == ~((size_t) 0) 83 || (size_t) size > elf->maximum_size) 84 && unlikely (ftruncate (elf->fildes, size) != 0)) 85 { 86 __libelf_seterrno (ELF_E_WRITE_ERROR); 87 return -1; 88 } 89 90 /* Try to map the file if this isn't done yet. */ 91 if (elf->map_address == NULL && elf->cmd == ELF_C_WRITE_MMAP) 92 { 93 #if _MUDFLAP 94 /* Mudflap doesn't grok that our mmap'd data is ok. */ 95 #else 96 elf->map_address = mmap (NULL, size, PROT_READ | PROT_WRITE, 97 MAP_SHARED, elf->fildes, 0); 98 if (unlikely (elf->map_address == MAP_FAILED)) 99 elf->map_address = NULL; 100 #endif 101 } 102 103 if (elf->map_address != NULL) 104 { 105 /* The file is mmaped. */ 106 if ((class == ELFCLASS32 107 ? __elf32_updatemmap (elf, change_bo, shnum) 108 : __elf64_updatemmap (elf, change_bo, shnum)) != 0) 109 /* Some problem while writing. */ 110 size = -1; 111 } 112 else 113 { 114 /* The file is not mmaped. */ 115 if ((class == ELFCLASS32 116 ? __elf32_updatefile (elf, change_bo, shnum) 117 : __elf64_updatefile (elf, change_bo, shnum)) != 0) 118 /* Some problem while writing. */ 119 size = -1; 120 } 121 122 if (size != -1 123 && elf->parent == NULL 124 && elf->maximum_size != ~((size_t) 0) 125 && (size_t) size < elf->maximum_size 126 && unlikely (ftruncate (elf->fildes, size) != 0)) 127 { 128 __libelf_seterrno (ELF_E_WRITE_ERROR); 129 size = -1; 130 } 131 132 /* POSIX says that ftruncate and write may clear the S_ISUID and S_ISGID 133 mode bits. So make sure we restore them afterwards if they were set. 134 This is not atomic if someone else chmod's the file while we operate. */ 135 if (size != -1 136 && unlikely (st.st_mode & (S_ISUID | S_ISGID)) 137 /* fchmod ignores the bits we cannot change. */ 138 && unlikely (fchmod (elf->fildes, st.st_mode) != 0)) 139 { 140 __libelf_seterrno (ELF_E_WRITE_ERROR); 141 size = -1; 142 } 143 144 if (size != -1 && elf->parent == NULL) 145 elf->maximum_size = size; 146 147 return size; 148 } 149 150 151 off_t 152 elf_update (elf, cmd) 153 Elf *elf; 154 Elf_Cmd cmd; 155 { 156 size_t shnum; 157 off_t size; 158 int change_bo = 0; 159 160 if (cmd != ELF_C_NULL 161 && cmd != ELF_C_WRITE 162 && unlikely (cmd != ELF_C_WRITE_MMAP)) 163 { 164 __libelf_seterrno (ELF_E_INVALID_CMD); 165 return -1; 166 } 167 168 if (elf == NULL) 169 return -1; 170 171 if (elf->kind != ELF_K_ELF) 172 { 173 __libelf_seterrno (ELF_E_INVALID_HANDLE); 174 return -1; 175 } 176 177 rwlock_wrlock (elf->lock); 178 179 /* Make sure we have an ELF header. */ 180 if (elf->state.elf.ehdr == NULL) 181 { 182 __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR); 183 size = -1; 184 goto out; 185 } 186 187 /* Determine the number of sections. */ 188 shnum = (elf->state.elf.scns_last->cnt == 0 189 ? 0 190 : 1 + elf->state.elf.scns_last->data[elf->state.elf.scns_last->cnt - 1].index); 191 192 /* Update the ELF descriptor. First, place the program header. It 193 will come right after the ELF header. The count the size of all 194 sections and finally place the section table. */ 195 size = (elf->class == ELFCLASS32 196 ? __elf32_updatenull_wrlock (elf, &change_bo, shnum) 197 : __elf64_updatenull_wrlock (elf, &change_bo, shnum)); 198 if (likely (size != -1) 199 /* See whether we actually have to write out the data. */ 200 && (cmd == ELF_C_WRITE || cmd == ELF_C_WRITE_MMAP)) 201 { 202 if (elf->cmd != ELF_C_RDWR 203 && elf->cmd != ELF_C_RDWR_MMAP 204 && elf->cmd != ELF_C_WRITE 205 && unlikely (elf->cmd != ELF_C_WRITE_MMAP)) 206 { 207 __libelf_seterrno (ELF_E_UPDATE_RO); 208 size = -1; 209 } 210 else if (unlikely (elf->fildes == -1)) 211 { 212 /* We closed the file already. */ 213 __libelf_seterrno (ELF_E_FD_DISABLED); 214 size = -1; 215 } 216 else 217 size = write_file (elf, size, change_bo, shnum); 218 } 219 220 out: 221 rwlock_unlock (elf->lock); 222 223 return size; 224 } 225
