diff options
Diffstat (limited to 'libelf/elf_update.c')
| -rw-r--r-- | libelf/elf_update.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/libelf/elf_update.c b/libelf/elf_update.c new file mode 100644 index 00000000..5d6c6b7a --- /dev/null +++ b/libelf/elf_update.c @@ -0,0 +1,178 @@ +/* Update data structures for changes and write them out. + Copyright (C) 1999, 2000, 2001, 2002, 2004, 2005 Red Hat, Inc. + Contributed by Ulrich Drepper <drepper@redhat.com>, 1999. + + This program 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. + + This program 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, write to the Free Software Foundation, + Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <libelf.h> +#include <unistd.h> +#include <sys/mman.h> + +#include "libelfP.h" + + +static off_t +write_file (Elf *elf, off_t size, int change_bo, size_t shnum) +{ + int class = elf->class; + + /* 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; + } + + 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 (elf, &change_bo, shnum) + : __elf64_updatenull (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 + { + if (elf->parent != NULL) + { + extern int puts (const char *); + puts ("this is an archive member"); + } + + size = write_file (elf, size, change_bo, shnum); + } + } + + out: + rwlock_unlock (elf->lock); + + return size; +} |