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Diffstat (limited to 'libelf/elf_getshdrstrndx.c')
| -rw-r--r-- | libelf/elf_getshdrstrndx.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/libelf/elf_getshdrstrndx.c b/libelf/elf_getshdrstrndx.c new file mode 100644 index 00000000..5e89b343 --- /dev/null +++ b/libelf/elf_getshdrstrndx.c @@ -0,0 +1,205 @@ +/* Return section index of section header string table. + Copyright (C) 2002, 2005, 2009 Red Hat, Inc. + This file is part of Red Hat elfutils. + Written by Ulrich Drepper <drepper@redhat.com>, 2002. + + 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 + <http://www.openinventionnetwork.com>. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <assert.h> +#include <errno.h> +#include <gelf.h> +#include <stddef.h> +#include <unistd.h> + +#include <system.h> +#include "libelfP.h" +#include "common.h" + + +int +elf_getshdrstrndx (elf, dst) + Elf *elf; + size_t *dst; +{ + int result = 0; + + if (elf == NULL) + return -1; + + if (unlikely (elf->kind != ELF_K_ELF)) + { + __libelf_seterrno (ELF_E_INVALID_HANDLE); + return -1; + } + + rwlock_rdlock (elf->lock); + + /* We rely here on the fact that the `elf' element is a common prefix + of `elf32' and `elf64'. */ + assert (offsetof (struct Elf, state.elf.ehdr) + == offsetof (struct Elf, state.elf32.ehdr)); + assert (sizeof (elf->state.elf.ehdr) + == sizeof (elf->state.elf32.ehdr)); + assert (offsetof (struct Elf, state.elf.ehdr) + == offsetof (struct Elf, state.elf64.ehdr)); + assert (sizeof (elf->state.elf.ehdr) + == sizeof (elf->state.elf64.ehdr)); + + if (unlikely (elf->state.elf.ehdr == NULL)) + { + __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR); + result = -1; + } + else + { + Elf32_Word num; + + num = (elf->class == ELFCLASS32 + ? elf->state.elf32.ehdr->e_shstrndx + : elf->state.elf64.ehdr->e_shstrndx); + + /* Determine whether the index is too big to fit in the ELF + header. */ + if (unlikely (num == SHN_XINDEX)) + { + /* Yes. Search the zeroth section header. */ + if (elf->class == ELFCLASS32) + { + size_t offset; + + if (elf->state.elf32.scns.data[0].shdr.e32 != NULL) + { + num = elf->state.elf32.scns.data[0].shdr.e32->sh_link; + goto success; + } + + offset = elf->state.elf32.ehdr->e_shoff; + + if (elf->map_address != NULL + && elf->state.elf32.ehdr->e_ident[EI_DATA] == MY_ELFDATA + && (ALLOW_UNALIGNED + || (((size_t) ((char *) elf->map_address + offset)) + & (__alignof__ (Elf32_Shdr) - 1)) == 0)) + /* We can directly access the memory. */ + num = ((Elf32_Shdr *) (elf->map_address + offset))->sh_link; + else + { + /* We avoid reading in all the section headers. Just read + the first one. */ + Elf32_Shdr shdr_mem; + + if (unlikely (pread_retry (elf->fildes, &shdr_mem, + sizeof (Elf32_Shdr), offset) + != sizeof (Elf32_Shdr))) + { + /* We must be able to read this ELF section header. */ + __libelf_seterrno (ELF_E_INVALID_FILE); + result = -1; + goto out; + } + + if (elf->state.elf32.ehdr->e_ident[EI_DATA] != MY_ELFDATA) + CONVERT (shdr_mem.sh_link); + num = shdr_mem.sh_link; + } + } + else + { + if (elf->state.elf64.scns.data[0].shdr.e64 != NULL) + { + num = elf->state.elf64.scns.data[0].shdr.e64->sh_link; + goto success; + } + + size_t offset = elf->state.elf64.ehdr->e_shoff; + + if (elf->map_address != NULL + && elf->state.elf64.ehdr->e_ident[EI_DATA] == MY_ELFDATA + && (ALLOW_UNALIGNED + || (((size_t) ((char *) elf->map_address + offset)) + & (__alignof__ (Elf64_Shdr) - 1)) == 0)) + /* We can directly access the memory. */ + num = ((Elf64_Shdr *) (elf->map_address + offset))->sh_link; + else + { + /* We avoid reading in all the section headers. Just read + the first one. */ + Elf64_Shdr shdr_mem; + + if (unlikely (pread_retry (elf->fildes, &shdr_mem, + sizeof (Elf64_Shdr), offset) + != sizeof (Elf64_Shdr))) + { + /* We must be able to read this ELF section header. */ + __libelf_seterrno (ELF_E_INVALID_FILE); + result = -1; + goto out; + } + + if (elf->state.elf64.ehdr->e_ident[EI_DATA] != MY_ELFDATA) + CONVERT (shdr_mem.sh_link); + num = shdr_mem.sh_link; + } + } + } + + /* Store the result. */ + success: + *dst = num; + } + + out: + rwlock_unlock (elf->lock); + + return result; +} +INTDEF(elf_getshdrstrndx) +/* Alias for the deprecated name. */ +strong_alias (elf_getshdrstrndx, elf_getshstrndx) |