diff options
Diffstat (limited to 'src/libelf/elf32_getshdr.c')
| -rw-r--r-- | src/libelf/elf32_getshdr.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/src/libelf/elf32_getshdr.c b/src/libelf/elf32_getshdr.c new file mode 100644 index 00000000..8d650d9f --- /dev/null +++ b/src/libelf/elf32_getshdr.c @@ -0,0 +1,294 @@ +/* Return section header. + Copyright (C) 1998, 1999, 2000, 2001, 2002, 2005, 2007, 2009 Red Hat, Inc. + This file is part of Red Hat elfutils. + Written by Ulrich Drepper <drepper@redhat.com>, 1998. + + 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 <stdbool.h> +#include <unistd.h> + +#include <system.h> +#include "libelfP.h" +#include "common.h" + +#ifndef LIBELFBITS +# define LIBELFBITS 32 +#endif + + +static ElfW2(LIBELFBITS,Shdr) * +load_shdr_wrlock (Elf_Scn *scn) +{ + ElfW2(LIBELFBITS,Shdr) *result; + + /* Read the section header table. */ + Elf *elf = scn->elf; + ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr; + + /* Try again, maybe the data is there now. */ + result = scn->shdr.ELFW(e,LIBELFBITS); + if (result != NULL) + goto out; + + size_t shnum; + if (__elf_getshdrnum_rdlock (elf, &shnum) != 0) + goto out; + size_t size = shnum * sizeof (ElfW2(LIBELFBITS,Shdr)); + + /* Allocate memory for the section headers. We know the number + of entries from the ELF header. */ + ElfW2(LIBELFBITS,Shdr) *shdr = elf->state.ELFW(elf,LIBELFBITS).shdr = + (ElfW2(LIBELFBITS,Shdr) *) malloc (size); + if (elf->state.ELFW(elf,LIBELFBITS).shdr == NULL) + { + __libelf_seterrno (ELF_E_NOMEM); + goto out; + } + elf->state.ELFW(elf,LIBELFBITS).shdr_malloced = 1; + + if (elf->map_address != NULL) + { + ElfW2(LIBELFBITS,Shdr) *notcvt; + + /* All the data is already mapped. If we could use it + directly this would already have happened. */ + void *file_shdr = ((char *) elf->map_address + + elf->start_offset + ehdr->e_shoff); + + assert (ehdr->e_ident[EI_DATA] != MY_ELFDATA + || (! ALLOW_UNALIGNED + && ((uintptr_t) file_shdr + & (__alignof__ (ElfW2(LIBELFBITS,Shdr)) - 1)) != 0)); + + /* Now copy the data and at the same time convert the byte order. */ + if (ehdr->e_ident[EI_DATA] == MY_ELFDATA) + { + assert (! ALLOW_UNALIGNED); + memcpy (shdr, file_shdr, size); + } + else + { + if (ALLOW_UNALIGNED + || ((uintptr_t) file_shdr + & (__alignof__ (ElfW2(LIBELFBITS,Shdr)) - 1)) == 0) + notcvt = (ElfW2(LIBELFBITS,Shdr) *) + ((char *) elf->map_address + + elf->start_offset + ehdr->e_shoff); + else + { + notcvt = (ElfW2(LIBELFBITS,Shdr) *) alloca (size); + memcpy (notcvt, ((char *) elf->map_address + + elf->start_offset + ehdr->e_shoff), + size); + } + + for (size_t cnt = 0; cnt < shnum; ++cnt) + { + CONVERT_TO (shdr[cnt].sh_name, notcvt[cnt].sh_name); + CONVERT_TO (shdr[cnt].sh_type, notcvt[cnt].sh_type); + CONVERT_TO (shdr[cnt].sh_flags, notcvt[cnt].sh_flags); + CONVERT_TO (shdr[cnt].sh_addr, notcvt[cnt].sh_addr); + CONVERT_TO (shdr[cnt].sh_offset, notcvt[cnt].sh_offset); + CONVERT_TO (shdr[cnt].sh_size, notcvt[cnt].sh_size); + CONVERT_TO (shdr[cnt].sh_link, notcvt[cnt].sh_link); + CONVERT_TO (shdr[cnt].sh_info, notcvt[cnt].sh_info); + CONVERT_TO (shdr[cnt].sh_addralign, + notcvt[cnt].sh_addralign); + CONVERT_TO (shdr[cnt].sh_entsize, notcvt[cnt].sh_entsize); + + /* If this is a section with an extended index add a + reference in the section which uses the extended + index. */ + if (shdr[cnt].sh_type == SHT_SYMTAB_SHNDX + && shdr[cnt].sh_link < shnum) + elf->state.ELFW(elf,LIBELFBITS).scns.data[shdr[cnt].sh_link].shndx_index + = cnt; + + /* Set the own shndx_index field in case it has not yet + been set. */ + if (elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shndx_index == 0) + elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shndx_index + = -1; + } + } + } + else if (likely (elf->fildes != -1)) + { + /* Read the header. */ + ssize_t n = pread_retry (elf->fildes, + elf->state.ELFW(elf,LIBELFBITS).shdr, size, + elf->start_offset + ehdr->e_shoff); + if (unlikely ((size_t) n != size)) + { + /* Severe problems. We cannot read the data. */ + __libelf_seterrno (ELF_E_READ_ERROR); + goto free_and_out; + } + + /* If the byte order of the file is not the same as the one + of the host convert the data now. */ + if (ehdr->e_ident[EI_DATA] != MY_ELFDATA) + for (size_t cnt = 0; cnt < shnum; ++cnt) + { + CONVERT (shdr[cnt].sh_name); + CONVERT (shdr[cnt].sh_type); + CONVERT (shdr[cnt].sh_flags); + CONVERT (shdr[cnt].sh_addr); + CONVERT (shdr[cnt].sh_offset); + CONVERT (shdr[cnt].sh_size); + CONVERT (shdr[cnt].sh_link); + CONVERT (shdr[cnt].sh_info); + CONVERT (shdr[cnt].sh_addralign); + CONVERT (shdr[cnt].sh_entsize); + } + } + else + { + /* The file descriptor was already enabled and not all data was + read. Undo the allocation. */ + __libelf_seterrno (ELF_E_FD_DISABLED); + + free_and_out: + free (shdr); + elf->state.ELFW(elf,LIBELFBITS).shdr = NULL; + elf->state.ELFW(elf,LIBELFBITS).shdr_malloced = 0; + + goto out; + } + + /* Set the pointers in the `scn's. */ + for (size_t cnt = 0; cnt < shnum; ++cnt) + elf->state.ELFW(elf,LIBELFBITS).scns.data[cnt].shdr.ELFW(e,LIBELFBITS) + = &elf->state.ELFW(elf,LIBELFBITS).shdr[cnt]; + + result = scn->shdr.ELFW(e,LIBELFBITS); + assert (result != NULL); + +out: + return result; +} + +static bool +scn_valid (Elf_Scn *scn) +{ + if (scn == NULL) + return false; + + if (unlikely (scn->elf->state.elf.ehdr == NULL)) + { + __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR); + return false; + } + + if (unlikely (scn->elf->class != ELFW(ELFCLASS,LIBELFBITS))) + { + __libelf_seterrno (ELF_E_INVALID_CLASS); + return false; + } + + return true; +} + +ElfW2(LIBELFBITS,Shdr) * +__elfw2(LIBELFBITS,getshdr_rdlock) (scn) + Elf_Scn *scn; +{ + ElfW2(LIBELFBITS,Shdr) *result; + + if (!scn_valid (scn)) + return NULL; + + result = scn->shdr.ELFW(e,LIBELFBITS); + if (result == NULL) + { + rwlock_unlock (scn->elf->lock); + rwlock_wrlock (scn->elf->lock); + result = scn->shdr.ELFW(e,LIBELFBITS); + if (result == NULL) + result = load_shdr_wrlock (scn); + } + + return result; +} + +ElfW2(LIBELFBITS,Shdr) * +__elfw2(LIBELFBITS,getshdr_wrlock) (scn) + Elf_Scn *scn; +{ + ElfW2(LIBELFBITS,Shdr) *result; + + if (!scn_valid (scn)) + return NULL; + + result = scn->shdr.ELFW(e,LIBELFBITS); + if (result == NULL) + result = load_shdr_wrlock (scn); + + return result; +} + +ElfW2(LIBELFBITS,Shdr) * +elfw2(LIBELFBITS,getshdr) (scn) + Elf_Scn *scn; +{ + ElfW2(LIBELFBITS,Shdr) *result; + + if (!scn_valid (scn)) + return NULL; + + rwlock_rdlock (scn->elf->lock); + result = __elfw2(LIBELFBITS,getshdr_rdlock) (scn); + rwlock_unlock (scn->elf->lock); + + return result; +} |