diff options
Diffstat (limited to 'src/libelf/elf32_updatefile.c')
| -rw-r--r-- | src/libelf/elf32_updatefile.c | 820 |
1 files changed, 820 insertions, 0 deletions
diff --git a/src/libelf/elf32_updatefile.c b/src/libelf/elf32_updatefile.c new file mode 100644 index 00000000..898cf1ab --- /dev/null +++ b/src/libelf/elf32_updatefile.c @@ -0,0 +1,820 @@ +/* Write changed data structures. + Copyright (C) 2000-2010 Red Hat, Inc. + This file is part of Red Hat elfutils. + Written by Ulrich Drepper <drepper@redhat.com>, 2000. + + 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 <libelf.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/mman.h> +#include <sys/param.h> + +#include <system.h> +#include "libelfP.h" + + +#ifndef LIBELFBITS +# define LIBELFBITS 32 +#endif + + +static int +compare_sections (const void *a, const void *b) +{ + const Elf_Scn **scna = (const Elf_Scn **) a; + const Elf_Scn **scnb = (const Elf_Scn **) b; + + if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_offset + < (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_offset) + return -1; + + if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_offset + > (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_offset) + return 1; + + if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_size + < (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_size) + return -1; + + if ((*scna)->shdr.ELFW(e,LIBELFBITS)->sh_size + > (*scnb)->shdr.ELFW(e,LIBELFBITS)->sh_size) + return 1; + + if ((*scna)->index < (*scnb)->index) + return -1; + + if ((*scna)->index > (*scnb)->index) + return 1; + + return 0; +} + + +/* Insert the sections in the list into the provided array and sort + them according to their start offsets. For sections with equal + start offsets, the size is used; for sections with equal start + offsets and sizes, the section index is used. Sorting by size + ensures that zero-length sections are processed first, which + is what we want since they do not advance our file writing position. */ +static void +sort_sections (Elf_Scn **scns, Elf_ScnList *list) +{ + Elf_Scn **scnp = scns; + do + for (size_t cnt = 0; cnt < list->cnt; ++cnt) + *scnp++ = &list->data[cnt]; + while ((list = list->next) != NULL); + + qsort (scns, scnp - scns, sizeof (*scns), compare_sections); +} + + +int +internal_function +__elfw2(LIBELFBITS,updatemmap) (Elf *elf, int change_bo, size_t shnum) +{ + bool previous_scn_changed = false; + + /* We need the ELF header several times. */ + ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr; + + /* Write out the ELF header. */ + if ((elf->state.ELFW(elf,LIBELFBITS).ehdr_flags | elf->flags) & ELF_F_DIRTY) + { + /* If the type sizes should be different at some time we have to + rewrite this code. */ + assert (sizeof (ElfW2(LIBELFBITS,Ehdr)) + == elf_typesize (LIBELFBITS, ELF_T_EHDR, 1)); + + if (unlikely (change_bo)) + { + /* Today there is only one version of the ELF header. */ +#if EV_NUM != 2 + xfct_t fctp; + fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR]; +#else +# undef fctp +# define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR] +#endif + + /* Do the real work. */ + (*fctp) ((char *) elf->map_address + elf->start_offset, ehdr, + sizeof (ElfW2(LIBELFBITS,Ehdr)), 1); + } + else + memcpy (elf->map_address + elf->start_offset, ehdr, + sizeof (ElfW2(LIBELFBITS,Ehdr))); + + elf->state.ELFW(elf,LIBELFBITS).ehdr_flags &= ~ELF_F_DIRTY; + + /* We start writing sections after the ELF header only if there is + no program header. */ + previous_scn_changed = elf->state.ELFW(elf,LIBELFBITS).phdr == NULL; + } + + size_t phnum; + if (unlikely (__elf_getphdrnum_rdlock (elf, &phnum) != 0)) + return -1; + + /* Write out the program header table. */ + if (elf->state.ELFW(elf,LIBELFBITS).phdr != NULL + && ((elf->state.ELFW(elf,LIBELFBITS).phdr_flags | elf->flags) + & ELF_F_DIRTY)) + { + /* If the type sizes should be different at some time we have to + rewrite this code. */ + assert (sizeof (ElfW2(LIBELFBITS,Phdr)) + == elf_typesize (LIBELFBITS, ELF_T_PHDR, 1)); + + /* Maybe the user wants a gap between the ELF header and the program + header. */ + if (ehdr->e_phoff > ehdr->e_ehsize) + memset (elf->map_address + elf->start_offset + ehdr->e_ehsize, + __libelf_fill_byte, ehdr->e_phoff - ehdr->e_ehsize); + + if (unlikely (change_bo)) + { + /* Today there is only one version of the ELF header. */ +#if EV_NUM != 2 + xfct_t fctp; + fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR]; +#else +# undef fctp +# define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR] +#endif + + /* Do the real work. */ + (*fctp) (elf->map_address + elf->start_offset + ehdr->e_phoff, + elf->state.ELFW(elf,LIBELFBITS).phdr, + sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum, 1); + } + else + memcpy (elf->map_address + elf->start_offset + ehdr->e_phoff, + elf->state.ELFW(elf,LIBELFBITS).phdr, + sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum); + + elf->state.ELFW(elf,LIBELFBITS).phdr_flags &= ~ELF_F_DIRTY; + + /* We modified the program header. Maybe this created a gap so + we have to write fill bytes, if necessary. */ + previous_scn_changed = true; + } + + /* From now on we have to keep track of the last position to eventually + fill the gaps with the prescribed fill byte. */ + char *last_position = ((char *) elf->map_address + elf->start_offset + + MAX (elf_typesize (LIBELFBITS, ELF_T_EHDR, 1), + ehdr->e_phoff) + + elf_typesize (LIBELFBITS, ELF_T_PHDR, phnum)); + + /* Write all the sections. Well, only those which are modified. */ + if (shnum > 0) + { + Elf_ScnList *list = &elf->state.ELFW(elf,LIBELFBITS).scns; + Elf_Scn **scns = (Elf_Scn **) alloca (shnum * sizeof (Elf_Scn *)); + char *const shdr_start = ((char *) elf->map_address + elf->start_offset + + ehdr->e_shoff); + char *const shdr_end = shdr_start + ehdr->e_shnum * ehdr->e_shentsize; + +#if EV_NUM != 2 + xfct_t shdr_fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR]; +#else +# undef shdr_fctp +# define shdr_fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR] +#endif +#define shdr_dest ((ElfW2(LIBELFBITS,Shdr) *) shdr_start) + + /* Get all sections into the array and sort them. */ + sort_sections (scns, list); + + /* We possibly have to copy the section header data because moving + the sections might overwrite the data. */ + for (size_t cnt = 0; cnt < shnum; ++cnt) + { + Elf_Scn *scn = scns[cnt]; + + if (!elf->state.ELFW(elf,LIBELFBITS).shdr_malloced + && (scn->shdr_flags & ELF_F_MALLOCED) == 0 + && scn->shdr.ELFW(e,LIBELFBITS) != &shdr_dest[scn->index]) + { + assert ((char *) elf->map_address + elf->start_offset + < (char *) scn->shdr.ELFW(e,LIBELFBITS)); + assert ((char *) scn->shdr.ELFW(e,LIBELFBITS) + < ((char *) elf->map_address + elf->start_offset + + elf->maximum_size)); + + void *p = alloca (sizeof (ElfW2(LIBELFBITS,Shdr))); + scn->shdr.ELFW(e,LIBELFBITS) + = memcpy (p, scn->shdr.ELFW(e,LIBELFBITS), + sizeof (ElfW2(LIBELFBITS,Shdr))); + } + + /* If the file is mmaped and the original position of the + section in the file is lower than the new position we + need to save the section content since otherwise it is + overwritten before it can be copied. If there are + multiple data segments in the list only the first can be + from the file. */ + if (((char *) elf->map_address + elf->start_offset + <= (char *) scn->data_list.data.d.d_buf) + && ((char *) scn->data_list.data.d.d_buf + < ((char *) elf->map_address + elf->start_offset + + elf->maximum_size)) + && (((char *) elf->map_address + elf->start_offset + + scn->shdr.ELFW(e,LIBELFBITS)->sh_offset) + > (char *) scn->data_list.data.d.d_buf)) + { + void *p = malloc (scn->data_list.data.d.d_size); + if (p == NULL) + { + __libelf_seterrno (ELF_E_NOMEM); + return -1; + } + scn->data_list.data.d.d_buf = scn->data_base + = memcpy (p, scn->data_list.data.d.d_buf, + scn->data_list.data.d.d_size); + } + } + + /* Iterate over all the section in the order in which they + appear in the output file. */ + for (size_t cnt = 0; cnt < shnum; ++cnt) + { + Elf_Scn *scn = scns[cnt]; + if (scn->index == 0) + { + /* The dummy section header entry. It should not be + possible to mark this "section" as dirty. */ + assert ((scn->flags & ELF_F_DIRTY) == 0); + continue; + } + + ElfW2(LIBELFBITS,Shdr) *shdr = scn->shdr.ELFW(e,LIBELFBITS); + if (shdr->sh_type == SHT_NOBITS) + goto next; + + char *scn_start = ((char *) elf->map_address + + elf->start_offset + shdr->sh_offset); + Elf_Data_List *dl = &scn->data_list; + bool scn_changed = false; + + void fill_mmap (size_t offset) + { + size_t written = 0; + + if (last_position < shdr_start) + { + written = MIN (scn_start + offset - last_position, + shdr_start - last_position); + + memset (last_position, __libelf_fill_byte, written); + } + + if (last_position + written != scn_start + offset + && shdr_end < scn_start + offset) + { + char *fill_start = MAX (shdr_end, scn_start); + memset (fill_start, __libelf_fill_byte, + scn_start + offset - fill_start); + } + } + + if (scn->data_list_rear != NULL) + do + { + assert (dl->data.d.d_off >= 0); + assert ((GElf_Off) dl->data.d.d_off <= shdr->sh_size); + assert (dl->data.d.d_size <= (shdr->sh_size + - (GElf_Off) dl->data.d.d_off)); + + /* If there is a gap, fill it. */ + if (scn_start + dl->data.d.d_off > last_position + && (dl->data.d.d_off == 0 + || ((scn->flags | dl->flags | elf->flags) + & ELF_F_DIRTY) != 0)) + { + fill_mmap (dl->data.d.d_off); + last_position = scn_start + dl->data.d.d_off; + } + + if ((scn->flags | dl->flags | elf->flags) & ELF_F_DIRTY) + { + /* Let it go backward if the sections use a bogus + layout with overlaps. We'll overwrite the stupid + user's section data with the latest one, rather than + crashing. */ + + last_position = scn_start + dl->data.d.d_off; + + if (unlikely (change_bo)) + { +#if EV_NUM != 2 + xfct_t fctp; + fctp = __elf_xfctstom[__libelf_version - 1][dl->data.d.d_version - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type]; +#else +# undef fctp +# define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type] +#endif + + /* Do the real work. */ + (*fctp) (last_position, dl->data.d.d_buf, + dl->data.d.d_size, 1); + + last_position += dl->data.d.d_size; + } + else + last_position = mempcpy (last_position, + dl->data.d.d_buf, + dl->data.d.d_size); + + scn_changed = true; + } + else + last_position += dl->data.d.d_size; + + assert (scn_start + dl->data.d.d_off + dl->data.d.d_size + == last_position); + + dl->flags &= ~ELF_F_DIRTY; + + dl = dl->next; + } + while (dl != NULL); + else + { + /* If the previous section (or the ELF/program + header) changed we might have to fill the gap. */ + if (scn_start > last_position && previous_scn_changed) + fill_mmap (0); + + /* We have to trust the existing section header information. */ + last_position = scn_start + shdr->sh_size; + } + + + previous_scn_changed = scn_changed; + next: + scn->flags &= ~ELF_F_DIRTY; + } + + /* Fill the gap between last section and section header table if + necessary. */ + if ((elf->flags & ELF_F_DIRTY) + && last_position < ((char *) elf->map_address + elf->start_offset + + ehdr->e_shoff)) + memset (last_position, __libelf_fill_byte, + (char *) elf->map_address + elf->start_offset + ehdr->e_shoff + - last_position); + + /* Write the section header table entry if necessary. */ + for (size_t cnt = 0; cnt < shnum; ++cnt) + { + Elf_Scn *scn = scns[cnt]; + + if ((scn->shdr_flags | elf->flags) & ELF_F_DIRTY) + { + if (unlikely (change_bo)) + (*shdr_fctp) (&shdr_dest[scn->index], + scn->shdr.ELFW(e,LIBELFBITS), + sizeof (ElfW2(LIBELFBITS,Shdr)), 1); + else + memcpy (&shdr_dest[scn->index], + scn->shdr.ELFW(e,LIBELFBITS), + sizeof (ElfW2(LIBELFBITS,Shdr))); + + /* If we previously made a copy of the section header + entry we now have to adjust the pointer again so + point to new place in the mapping. */ + if (!elf->state.ELFW(elf,LIBELFBITS).shdr_malloced + && (scn->shdr_flags & ELF_F_MALLOCED) == 0) + scn->shdr.ELFW(e,LIBELFBITS) = &shdr_dest[scn->index]; + + scn->shdr_flags &= ~ELF_F_DIRTY; + } + } + } + + /* That was the last part. Clear the overall flag. */ + elf->flags &= ~ELF_F_DIRTY; + + /* Make sure the content hits the disk. */ + char *msync_start = ((char *) elf->map_address + + (elf->start_offset & ~(sysconf (_SC_PAGESIZE) - 1))); + char *msync_end = ((char *) elf->map_address + + elf->start_offset + ehdr->e_shoff + + ehdr->e_shentsize * shnum); + (void) msync (msync_start, msync_end - msync_start, MS_SYNC); + + return 0; +} + + +/* Size of the buffer we use to generate the blocks of fill bytes. */ +#define FILLBUFSIZE 4096 + +/* If we have to convert the section buffer contents we have to use + temporary buffer. Only buffers up to MAX_TMPBUF bytes are allocated + on the stack. */ +#define MAX_TMPBUF 32768 + + +/* Helper function to write out fill bytes. */ +static int +fill (int fd, off_t pos, size_t len, char *fillbuf, size_t *filledp) +{ + size_t filled = *filledp; + size_t fill_len = MIN (len, FILLBUFSIZE); + + if (unlikely (fill_len > filled) && filled < FILLBUFSIZE) + { + /* Initialize a few more bytes. */ + memset (fillbuf + filled, __libelf_fill_byte, fill_len - filled); + *filledp = filled = fill_len; + } + + do + { + /* This many bytes we want to write in this round. */ + size_t n = MIN (filled, len); + + if (unlikely ((size_t) pwrite_retry (fd, fillbuf, n, pos) != n)) + { + __libelf_seterrno (ELF_E_WRITE_ERROR); + return 1; + } + + pos += n; + len -= n; + } + while (len > 0); + + return 0; +} + + +int +internal_function +__elfw2(LIBELFBITS,updatefile) (Elf *elf, int change_bo, size_t shnum) +{ + char fillbuf[FILLBUFSIZE]; + size_t filled = 0; + bool previous_scn_changed = false; + + /* We need the ELF header several times. */ + ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr; + + /* Write out the ELF header. */ + if ((elf->state.ELFW(elf,LIBELFBITS).ehdr_flags | elf->flags) & ELF_F_DIRTY) + { + ElfW2(LIBELFBITS,Ehdr) tmp_ehdr; + ElfW2(LIBELFBITS,Ehdr) *out_ehdr = ehdr; + + /* If the type sizes should be different at some time we have to + rewrite this code. */ + assert (sizeof (ElfW2(LIBELFBITS,Ehdr)) + == elf_typesize (LIBELFBITS, ELF_T_EHDR, 1)); + + if (unlikely (change_bo)) + { + /* Today there is only one version of the ELF header. */ +#if EV_NUM != 2 + xfct_t fctp; + fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR]; +#else +# undef fctp +# define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_EHDR] +#endif + + /* Write the converted ELF header in a temporary buffer. */ + (*fctp) (&tmp_ehdr, ehdr, sizeof (ElfW2(LIBELFBITS,Ehdr)), 1); + + /* This is the buffer we want to write. */ + out_ehdr = &tmp_ehdr; + } + + /* Write out the ELF header. */ + if (unlikely (pwrite_retry (elf->fildes, out_ehdr, + sizeof (ElfW2(LIBELFBITS,Ehdr)), 0) + != sizeof (ElfW2(LIBELFBITS,Ehdr)))) + { + __libelf_seterrno (ELF_E_WRITE_ERROR); + return 1; + } + + elf->state.ELFW(elf,LIBELFBITS).ehdr_flags &= ~ELF_F_DIRTY; + + /* We start writing sections after the ELF header only if there is + no program header. */ + previous_scn_changed = elf->state.ELFW(elf,LIBELFBITS).phdr == NULL; + } + + /* If the type sizes should be different at some time we have to + rewrite this code. */ + assert (sizeof (ElfW2(LIBELFBITS,Phdr)) + == elf_typesize (LIBELFBITS, ELF_T_PHDR, 1)); + + size_t phnum; + if (unlikely (__elf_getphdrnum_rdlock (elf, &phnum) != 0)) + return -1; + + /* Write out the program header table. */ + if (elf->state.ELFW(elf,LIBELFBITS).phdr != NULL + && ((elf->state.ELFW(elf,LIBELFBITS).phdr_flags | elf->flags) + & ELF_F_DIRTY)) + { + ElfW2(LIBELFBITS,Phdr) *tmp_phdr = NULL; + ElfW2(LIBELFBITS,Phdr) *out_phdr = elf->state.ELFW(elf,LIBELFBITS).phdr; + + /* Maybe the user wants a gap between the ELF header and the program + header. */ + if (ehdr->e_phoff > ehdr->e_ehsize + && unlikely (fill (elf->fildes, ehdr->e_ehsize, + ehdr->e_phoff - ehdr->e_ehsize, fillbuf, &filled) + != 0)) + return 1; + + if (unlikely (change_bo)) + { + /* Today there is only one version of the ELF header. */ +#if EV_NUM != 2 + xfct_t fctp; + fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR]; +#else +# undef fctp +# define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_PHDR] +#endif + + /* Allocate sufficient memory. */ + tmp_phdr = (ElfW2(LIBELFBITS,Phdr) *) + malloc (sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum); + if (tmp_phdr == NULL) + { + __libelf_seterrno (ELF_E_NOMEM); + return 1; + } + + /* Write the converted ELF header in a temporary buffer. */ + (*fctp) (tmp_phdr, elf->state.ELFW(elf,LIBELFBITS).phdr, + sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum, 1); + + /* This is the buffer we want to write. */ + out_phdr = tmp_phdr; + } + + /* Write out the ELF header. */ + size_t phdr_size = sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum; + if (unlikely ((size_t) pwrite_retry (elf->fildes, out_phdr, + phdr_size, ehdr->e_phoff) + != phdr_size)) + { + __libelf_seterrno (ELF_E_WRITE_ERROR); + return 1; + } + + /* This is a no-op we we have not allocated any memory. */ + free (tmp_phdr); + + elf->state.ELFW(elf,LIBELFBITS).phdr_flags &= ~ELF_F_DIRTY; + + /* We modified the program header. Maybe this created a gap so + we have to write fill bytes, if necessary. */ + previous_scn_changed = true; + } + + /* From now on we have to keep track of the last position to eventually + fill the gaps with the prescribed fill byte. */ + off_t last_offset; + if (elf->state.ELFW(elf,LIBELFBITS).phdr == NULL) + last_offset = elf_typesize (LIBELFBITS, ELF_T_EHDR, 1); + else + last_offset = (ehdr->e_phoff + sizeof (ElfW2(LIBELFBITS,Phdr)) * phnum); + + /* Write all the sections. Well, only those which are modified. */ + if (shnum > 0) + { + off_t shdr_offset = elf->start_offset + ehdr->e_shoff; +#if EV_NUM != 2 + xfct_t shdr_fctp = __elf_xfctstom[__libelf_version - 1][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR]; +#else +# undef shdr_fctp +# define shdr_fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][ELF_T_SHDR] +#endif + + ElfW2(LIBELFBITS,Shdr) *shdr_data; + if (change_bo || elf->state.ELFW(elf,LIBELFBITS).shdr == NULL) + shdr_data = (ElfW2(LIBELFBITS,Shdr) *) + alloca (shnum * sizeof (ElfW2(LIBELFBITS,Shdr))); + else + shdr_data = elf->state.ELFW(elf,LIBELFBITS).shdr; + int shdr_flags = elf->flags; + + /* Get all sections into the array and sort them. */ + Elf_ScnList *list = &elf->state.ELFW(elf,LIBELFBITS).scns; + Elf_Scn **scns = (Elf_Scn **) alloca (shnum * sizeof (Elf_Scn *)); + sort_sections (scns, list); + + for (size_t cnt = 0; cnt < shnum; ++cnt) + { + Elf_Scn *scn = scns[cnt]; + if (scn->index == 0) + { + /* The dummy section header entry. It should not be + possible to mark this "section" as dirty. */ + assert ((scn->flags & ELF_F_DIRTY) == 0); + goto next; + } + + ElfW2(LIBELFBITS,Shdr) *shdr = scn->shdr.ELFW(e,LIBELFBITS); + if (shdr->sh_type == SHT_NOBITS) + goto next; + + off_t scn_start = elf->start_offset + shdr->sh_offset; + Elf_Data_List *dl = &scn->data_list; + bool scn_changed = false; + + if (scn->data_list_rear != NULL) + do + { + /* If there is a gap, fill it. */ + if (scn_start + dl->data.d.d_off > last_offset + && ((previous_scn_changed && dl->data.d.d_off == 0) + || ((scn->flags | dl->flags | elf->flags) + & ELF_F_DIRTY) != 0)) + { + if (unlikely (fill (elf->fildes, last_offset, + (scn_start + dl->data.d.d_off) + - last_offset, fillbuf, + &filled) != 0)) + return 1; + } + + if ((scn->flags | dl->flags | elf->flags) & ELF_F_DIRTY) + { + char tmpbuf[MAX_TMPBUF]; + void *buf = dl->data.d.d_buf; + + /* Let it go backward if the sections use a bogus + layout with overlaps. We'll overwrite the stupid + user's section data with the latest one, rather than + crashing. */ + + last_offset = scn_start + dl->data.d.d_off; + + if (unlikely (change_bo)) + { +#if EV_NUM != 2 + xfct_t fctp; + fctp = __elf_xfctstom[__libelf_version - 1][dl->data.d.d_version - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type]; +#else +# undef fctp +# define fctp __elf_xfctstom[0][EV_CURRENT - 1][ELFW(ELFCLASS, LIBELFBITS) - 1][dl->data.d.d_type] +#endif + + buf = tmpbuf; + if (dl->data.d.d_size > MAX_TMPBUF) + { + buf = malloc (dl->data.d.d_size); + if (buf == NULL) + { + __libelf_seterrno (ELF_E_NOMEM); + return 1; + } + } + + /* Do the real work. */ + (*fctp) (buf, dl->data.d.d_buf, dl->data.d.d_size, 1); + } + + ssize_t n = pwrite_retry (elf->fildes, buf, + dl->data.d.d_size, + last_offset); + if (unlikely ((size_t) n != dl->data.d.d_size)) + { + if (buf != dl->data.d.d_buf && buf != tmpbuf) + free (buf); + + __libelf_seterrno (ELF_E_WRITE_ERROR); + return 1; + } + + if (buf != dl->data.d.d_buf && buf != tmpbuf) + free (buf); + + scn_changed = true; + } + + last_offset += dl->data.d.d_size; + + dl->flags &= ~ELF_F_DIRTY; + + dl = dl->next; + } + while (dl != NULL); + else + { + /* If the previous section (or the ELF/program + header) changed we might have to fill the gap. */ + if (scn_start > last_offset && previous_scn_changed) + { + if (unlikely (fill (elf->fildes, last_offset, + scn_start - last_offset, fillbuf, + &filled) != 0)) + return 1; + } + + last_offset = scn_start + shdr->sh_size; + } + + previous_scn_changed = scn_changed; + next: + /* Collect the section header table information. */ + if (unlikely (change_bo)) + (*shdr_fctp) (&shdr_data[scn->index], + scn->shdr.ELFW(e,LIBELFBITS), + sizeof (ElfW2(LIBELFBITS,Shdr)), 1); + else if (elf->state.ELFW(elf,LIBELFBITS).shdr == NULL) + memcpy (&shdr_data[scn->index], scn->shdr.ELFW(e,LIBELFBITS), + sizeof (ElfW2(LIBELFBITS,Shdr))); + + shdr_flags |= scn->shdr_flags; + scn->shdr_flags &= ~ELF_F_DIRTY; + } + + /* Fill the gap between last section and section header table if + necessary. */ + if ((elf->flags & ELF_F_DIRTY) && last_offset < shdr_offset + && unlikely (fill (elf->fildes, last_offset, + shdr_offset - last_offset, + fillbuf, &filled) != 0)) + return 1; + + /* Write out the section header table. */ + if (shdr_flags & ELF_F_DIRTY + && unlikely ((size_t) pwrite_retry (elf->fildes, shdr_data, + sizeof (ElfW2(LIBELFBITS,Shdr)) + * shnum, shdr_offset) + != sizeof (ElfW2(LIBELFBITS,Shdr)) * shnum)) + { + __libelf_seterrno (ELF_E_WRITE_ERROR); + return 1; + } + } + + /* That was the last part. Clear the overall flag. */ + elf->flags &= ~ELF_F_DIRTY; + + return 0; +} |