/* Update data structures for changes and write them out. Copyright (C) 1999, 2000, 2001, 2002, 2004, 2005, 2006 Red Hat, Inc. This file is part of Red Hat elfutils. Contributed by Ulrich Drepper , 1999. Red Hat elfutils 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; version 2 of the License. Red Hat 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 Red Hat elfutils; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. In addition, as a special exception, Red Hat, Inc. gives You the additional right to link the code of Red Hat elfutils with code licensed under any Open Source Initiative certified open source license (http://www.opensource.org/licenses/index.php) which requires the distribution of source code with any binary distribution and to distribute linked combinations of the two. Non-GPL Code permitted under this exception must only link to the code of Red Hat elfutils through those well defined interfaces identified in the file named EXCEPTION found in the source code files (the "Approved Interfaces"). The files of Non-GPL Code may instantiate templates or use macros or inline functions from the Approved Interfaces without causing the resulting work to be covered by the GNU General Public License. Only Red Hat, Inc. may make changes or additions to the list of Approved Interfaces. Red Hat's grant of this exception is conditioned upon your not adding any new exceptions. If you wish to add a new Approved Interface or exception, please contact Red Hat. You must obey the GNU General Public License in all respects for all of the Red Hat elfutils code and other code used in conjunction with Red Hat elfutils except the Non-GPL Code covered by this exception. If you modify this file, you may extend this exception to your version of the file, but you are not obligated to do so. If you do not wish to provide this exception without modification, you must delete this exception statement from your version and license this file solely under the GPL without exception. Red Hat elfutils is an included package of the Open Invention Network. An included package of the Open Invention Network is a package for which Open Invention Network licensees cross-license their patents. No patent license is granted, either expressly or impliedly, by designation as an included package. Should you wish to participate in the Open Invention Network licensing program, please visit www.openinventionnetwork.com . */ #ifdef HAVE_CONFIG_H # include #endif #include #include #include #include #include "libelfP.h" static off_t write_file (Elf *elf, off_t size, int change_bo, size_t shnum) { int class = elf->class; /* Check the mode bits now, before modification might change them. */ struct stat st; if (unlikely (fstat (elf->fildes, &st) != 0)) { __libelf_seterrno (ELF_E_WRITE_ERROR); return -1; } /* Adjust the size in any case. We do this even if we use `write'. We cannot do this if this file is in an archive. We also don't do it *now* if we are shortening the file since this would prevent programs to use the data of the file in generating the new file. We truncate the file later in this case. */ if (elf->parent == NULL && (elf->maximum_size == ~((size_t) 0) || (size_t) size > elf->maximum_size) && unlikely (ftruncate (elf->fildes, size) != 0)) { __libelf_seterrno (ELF_E_WRITE_ERROR); return -1; } /* Try to map the file if this isn't done yet. */ if (elf->map_address == NULL && elf->cmd == ELF_C_WRITE_MMAP) { #if _MUDFLAP /* Mudflap doesn't grok that our mmap'd data is ok. */ #else elf->map_address = mmap (NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, elf->fildes, 0); if (unlikely (elf->map_address == MAP_FAILED)) elf->map_address = NULL; #endif } if (elf->map_address != NULL) { /* The file is mmaped. */ if ((class == ELFCLASS32 ? __elf32_updatemmap (elf, change_bo, shnum) : __elf64_updatemmap (elf, change_bo, shnum)) != 0) /* Some problem while writing. */ size = -1; } else { /* The file is not mmaped. */ if ((class == ELFCLASS32 ? __elf32_updatefile (elf, change_bo, shnum) : __elf64_updatefile (elf, change_bo, shnum)) != 0) /* Some problem while writing. */ size = -1; } if (size != -1 && elf->parent == NULL && elf->maximum_size != ~((size_t) 0) && (size_t) size < elf->maximum_size && unlikely (ftruncate (elf->fildes, size) != 0)) { __libelf_seterrno (ELF_E_WRITE_ERROR); size = -1; } /* POSIX says that ftruncate and write may clear the S_ISUID and S_ISGID mode bits. So make sure we restore them afterwards if they were set. This is not atomic if someone else chmod's the file while we operate. */ if (size != -1 && unlikely (st.st_mode & (S_ISUID | S_ISGID)) /* fchmod ignores the bits we cannot change. */ && unlikely (fchmod (elf->fildes, st.st_mode) != 0)) { __libelf_seterrno (ELF_E_WRITE_ERROR); size = -1; } if (size != -1 && elf->parent == NULL) elf->maximum_size = size; return size; } off_t elf_update (elf, cmd) Elf *elf; Elf_Cmd cmd; { size_t shnum; off_t size; int change_bo = 0; if (cmd != ELF_C_NULL && cmd != ELF_C_WRITE && unlikely (cmd != ELF_C_WRITE_MMAP)) { __libelf_seterrno (ELF_E_INVALID_CMD); return -1; } if (elf == NULL) return -1; if (elf->kind != ELF_K_ELF) { __libelf_seterrno (ELF_E_INVALID_HANDLE); return -1; } rwlock_wrlock (elf->lock); /* Make sure we have an ELF header. */ if (elf->state.elf.ehdr == NULL) { __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR); size = -1; goto out; } /* Determine the number of sections. */ shnum = (elf->state.elf.scns_last->cnt == 0 ? 0 : 1 + elf->state.elf.scns_last->data[elf->state.elf.scns_last->cnt - 1].index); /* Update the ELF descriptor. First, place the program header. It will come right after the ELF header. The count the size of all sections and finally place the section table. */ size = (elf->class == ELFCLASS32 ? __elf32_updatenull_wrlock (elf, &change_bo, shnum) : __elf64_updatenull_wrlock (elf, &change_bo, shnum)); if (likely (size != -1) /* See whether we actually have to write out the data. */ && (cmd == ELF_C_WRITE || cmd == ELF_C_WRITE_MMAP)) { if (elf->cmd != ELF_C_RDWR && elf->cmd != ELF_C_RDWR_MMAP && elf->cmd != ELF_C_WRITE && unlikely (elf->cmd != ELF_C_WRITE_MMAP)) { __libelf_seterrno (ELF_E_UPDATE_RO); size = -1; } else if (unlikely (elf->fildes == -1)) { /* We closed the file already. */ __libelf_seterrno (ELF_E_FD_DISABLED); size = -1; } else size = write_file (elf, size, change_bo, shnum); } out: rwlock_unlock (elf->lock); return size; }