[PATCH] ld support for position independent executables
Jakub Jelinek
jakub@redhat.com
Thu May 29 13:29:00 GMT 2003
Hi!
The following patch adds -pie (Position Independent Executable;
or --pic-executable) option to ld.
This option creates something between a shared library and normal
executable, which can be used for security exposed binaries so that their
base address can be randomized (either a constant address different on
each box through prelink -R (support for PIEs in prelink will be comming),
or totally random address).
The result is ET_DYN object like shared libraries, on the other side has
PT_INTERP segment, DT_DEBUG dynamic tag, can have DT_PREINIT_ARRAY{,SZ}
dynamic tags, doesn't export whole symbol table dynamically by default
and can do similar assumptions as binaries regarding symbol lookup
(e.g. all symbol lookups for symbols defined in the PIE will resolve
to the PIE copies, no interposition is possible).
glibc changes have been commited yesterday and earlier (addition of
/usr/lib/Scrt1.o and making elf-init.oS in libc_nonshared.a compiled with
-fpic), gcc will still need changing (at least specs file changes
to use Scrt1.o and pass -pie through to ld, but I'd like also to add
-fpie/-fPIE switches similar to -fpic/-fPIC, which would allow gcc to make
similar assumptions about symbol visibility as for binaries.
2003-05-29 Ulrich Drepper <drepper@redhat.com>
Jakub Jelinek <jakub@redhat.com>
bfd/
* elflink.h (elf_link_add_object_symbols): Use !info->executable
instead of info->shared where appropriate.
(bfd_elfNN_size_dynamic_sections, elf_link_output_extsym): Likewise.
* elflink.c (_bfd_elf_create_got_section): Likewise.
(_bfd_elf_link_create_dynamic_sections): Likewise.
(_bfd_elf_link_assign_sym_version): Likewise.
* elf32-i386.c (elf_i386_size_dynamic_sections): Create .interp section
and DT_DEBUG dynamic tag even for position independent executables.
* elf32-ppc.c (ppc_elf_size_dynamic_sections): Likewise.
* elf32-s390.c (elf_s390_size_dynamic_sections: Likewise.
* elf64-ppc.c (ppc64_elf_size_dynamic_sections: Likewise.
* elf64-s390.c (elf_s390_size_dynamic_sections: Likewise.
* elf64-x86-64.c (elf64_x86_64_size_dynamic_sections: Likewise.
* elfxx-ia64.c (elfNN_ia64_size_dynamic_sections: Likewise.
* elf32-sparc.c (elf32_sparc_size_dynamic_sections: Likewise.
* elf64-alpha.c (elf64_alpha_size_dynamic_sections: Likewise.
* elf64-sparc.c (sparc64_elf_size_dynamic_sections: Likewise.
include/
* bfdlink.h (struct bfd_link_info): Add pie and executable
bits.
ld/
* lexsup.c (OPTION_PIE): Define.
(ld_options): Add -pie and --pic-executable options.
(parse_args): Handle OPTION_PIE.
* ldmain.c (main): Initialize link_info.pie and
link_info.executable.
* genscripts.sh: Generate PIE scripts.
* ld.texinfo: Document -pie and --pic-executable options.
* emultempl/elf32.em (gld${EMULATION_NAME}_after_open):
(gld${EMULATION_NAME}_place_orphan): Likewise.
(gld${EMULATION_NAME}_get_script): Include PIE scripts.
* scripttempl/elf.sc: In PIE scripts set . the same way as in
shared scripts.
* emulparams/elf_i386.sh (GENERATE_PIE_SCRIPT): Set to yes.
* emulparams/elf64_ia64.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf32ppc.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf64ppc.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf_x86_64.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf_s390.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf32_sparc.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf64_sparc.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf64alpha.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf64_s390.sh (GENERATE_PIE_SCRIPT): Likewise.
* emulparams/elf_i386.sh (GENERATE_PIE_SCRIPT): Likewise.
--- bfd/elf32-i386.c.jj 2003-05-23 10:18:52.000000000 -0400
+++ bfd/elf32-i386.c 2003-05-28 03:18:13.000000000 -0400
@@ -1797,7 +1797,7 @@ elf_i386_size_dynamic_sections (output_b
if (htab->elf.dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
if (s == NULL)
@@ -1963,7 +1963,7 @@ elf_i386_size_dynamic_sections (output_b
#define add_dynamic_entry(TAG, VAL) \
bfd_elf32_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (! info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elflink.h.jj 2003-05-23 10:18:52.000000000 -0400
+++ bfd/elflink.h 2003-05-28 06:27:38.000000000 -0400
@@ -474,7 +474,7 @@ elf_link_add_object_symbols (abfd, info)
.gnu.warning.SYMBOL are treated as warning symbols for the given
symbol. This differs from .gnu.warning sections, which generate
warnings when they are included in an output file. */
- if (! info->shared)
+ if (info->executable)
{
asection *s;
@@ -1321,7 +1321,7 @@ elf_link_add_object_symbols (abfd, info)
}
else
new_flag = ELF_LINK_HASH_DEF_REGULAR;
- if (info->shared
+ if (! info->executable
|| (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
| ELF_LINK_HASH_REF_DYNAMIC)) != 0)
dynsym = TRUE;
@@ -2174,7 +2174,7 @@ NAME(bfd_elf,size_dynamic_sections) (out
if (bfd_get_section_by_name (output_bfd, ".preinit_array") != NULL)
{
/* DT_PREINIT_ARRAY is not allowed in shared library. */
- if (info->shared)
+ if (! info->executable)
{
bfd *sub;
asection *o;
@@ -2440,7 +2440,7 @@ NAME(bfd_elf,size_dynamic_sections) (out
if (info->flags_1)
{
- if (! info->shared)
+ if (info->executable)
info->flags_1 &= ~ (DF_1_INITFIRST
| DF_1_NODELETE
| DF_1_NOOPEN);
@@ -4417,7 +4417,8 @@ elf_link_output_extsym (h, data)
referenced by regular files, because we will already have issued
warnings for them. */
if (! finfo->info->relocateable
- && (! finfo->info->shared || ! finfo->info->allow_shlib_undefined)
+ && (finfo->info->executable
+ || ! finfo->info->allow_shlib_undefined)
&& h->root.type == bfd_link_hash_undefined
&& (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0
&& (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0
--- bfd/elf32-ppc.c.jj 2003-05-23 10:18:52.000000000 -0400
+++ bfd/elf32-ppc.c 2003-05-28 03:19:08.000000000 -0400
@@ -2920,7 +2920,7 @@ ppc_elf_size_dynamic_sections (output_bf
if (elf_hash_table (info)->dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (htab->elf.dynobj, ".interp");
BFD_ASSERT (s != NULL);
@@ -3102,7 +3102,7 @@ ppc_elf_size_dynamic_sections (output_bf
#define add_dynamic_entry(TAG, VAL) \
bfd_elf32_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (!info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elf32-s390.c.jj 2003-05-15 16:42:24.000000000 -0400
+++ bfd/elf32-s390.c 2003-05-28 03:19:32.000000000 -0400
@@ -1927,7 +1927,7 @@ elf_s390_size_dynamic_sections (output_b
if (htab->elf.dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
if (s == NULL)
@@ -2085,7 +2085,7 @@ elf_s390_size_dynamic_sections (output_b
#define add_dynamic_entry(TAG, VAL) \
bfd_elf32_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (! info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elf64-ppc.c.jj 2003-05-23 10:18:52.000000000 -0400
+++ bfd/elf64-ppc.c 2003-05-28 03:19:51.000000000 -0400
@@ -5737,7 +5737,7 @@ ppc64_elf_size_dynamic_sections (output_
if (htab->elf.dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
if (s == NULL)
@@ -5936,7 +5936,7 @@ ppc64_elf_size_dynamic_sections (output_
#define add_dynamic_entry(TAG, VAL) \
bfd_elf64_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (!info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elf64-s390.c.jj 2003-05-15 16:42:25.000000000 -0400
+++ bfd/elf64-s390.c 2003-05-28 03:20:08.000000000 -0400
@@ -1898,7 +1898,7 @@ elf_s390_size_dynamic_sections (output_b
if (htab->elf.dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
if (s == NULL)
@@ -2056,7 +2056,7 @@ elf_s390_size_dynamic_sections (output_b
#define add_dynamic_entry(TAG, VAL) \
bfd_elf64_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (! info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elf64-x86-64.c.jj 2003-05-05 17:46:47.000000000 -0400
+++ bfd/elf64-x86-64.c 2003-05-28 05:44:30.000000000 -0400
@@ -1618,7 +1618,7 @@ elf64_x86_64_size_dynamic_sections (outp
if (htab->elf.dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
if (s == NULL)
@@ -1779,7 +1779,7 @@ elf64_x86_64_size_dynamic_sections (outp
#define add_dynamic_entry(TAG, VAL) \
bfd_elf64_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (! info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elfxx-ia64.c.jj 2003-05-15 16:42:25.000000000 -0400
+++ bfd/elfxx-ia64.c 2003-05-28 03:24:40.000000000 -0400
@@ -2903,7 +2903,7 @@ elfNN_ia64_size_dynamic_sections (output
/* Set the contents of the .interp section to the interpreter. */
if (ia64_info->root.dynamic_sections_created
- && !info->shared)
+ && info->executable)
{
sec = bfd_get_section_by_name (dynobj, ".interp");
BFD_ASSERT (sec != NULL);
@@ -3078,7 +3078,7 @@ elfNN_ia64_size_dynamic_sections (output
later (in finish_dynamic_sections) but we must add the entries now
so that we get the correct size for the .dynamic section. */
- if (!info->shared)
+ if (info->executable)
{
/* The DT_DEBUG entry is filled in by the dynamic linker and used
by the debugger. */
--- bfd/elf32-sparc.c.jj 2003-05-28 03:03:45.000000000 -0400
+++ bfd/elf32-sparc.c 2003-05-28 03:20:48.000000000 -0400
@@ -1820,7 +1820,7 @@ elf32_sparc_size_dynamic_sections (outpu
if (elf_hash_table (info)->dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
BFD_ASSERT (s != NULL);
@@ -1997,7 +1997,7 @@ elf32_sparc_size_dynamic_sections (outpu
#define add_dynamic_entry(TAG, VAL) \
bfd_elf32_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (!info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elf64-alpha.c.jj 2003-05-15 16:42:25.000000000 -0400
+++ bfd/elf64-alpha.c 2003-05-28 03:21:20.000000000 -0400
@@ -4090,7 +4090,7 @@ elf64_alpha_size_dynamic_sections (outpu
if (elf_hash_table (info)->dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (!info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
BFD_ASSERT (s != NULL);
@@ -4176,7 +4176,7 @@ elf64_alpha_size_dynamic_sections (outpu
#define add_dynamic_entry(TAG, VAL) \
bfd_elf64_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
- if (!info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elf64-sparc.c.jj 2003-05-28 03:03:45.000000000 -0400
+++ bfd/elf64-sparc.c 2003-05-28 03:21:59.000000000 -0400
@@ -1781,7 +1781,7 @@ sparc64_elf_size_dynamic_sections (outpu
if (elf_hash_table (info)->dynamic_sections_created)
{
/* Set the contents of the .interp section to the interpreter. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_get_section_by_name (dynobj, ".interp");
BFD_ASSERT (s != NULL);
@@ -1880,7 +1880,7 @@ sparc64_elf_size_dynamic_sections (outpu
struct elf_strtab_hash *dynstr;
struct elf_link_hash_table *eht = elf_hash_table (info);
- if (!info->shared)
+ if (info->executable)
{
if (!add_dynamic_entry (DT_DEBUG, 0))
return FALSE;
--- bfd/elflink.c.jj 2003-05-23 10:18:52.000000000 -0400
+++ bfd/elflink.c 2003-05-28 06:20:40.000000000 -0400
@@ -94,7 +94,7 @@ _bfd_elf_create_got_section (abfd, info)
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
h->type = STT_OBJECT;
- if (info->shared
+ if (! info->executable
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
@@ -144,7 +144,7 @@ _bfd_elf_link_create_dynamic_sections (a
/* A dynamically linked executable has a .interp section, but a
shared library does not. */
- if (! info->shared)
+ if (info->executable)
{
s = bfd_make_section (abfd, ".interp");
if (s == NULL
@@ -227,7 +227,7 @@ _bfd_elf_link_create_dynamic_sections (a
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
h->type = STT_OBJECT;
- if (info->shared
+ if (! info->executable
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
@@ -295,7 +295,7 @@ _bfd_elf_create_dynamic_sections (abfd,
h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
h->type = STT_OBJECT;
- if (info->shared
+ if (! info->executable
&& ! _bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
}
@@ -1760,7 +1760,7 @@ _bfd_elf_link_assign_sym_version (h, dat
/* If we are building an application, we need to create a
version node for this version. */
- if (t == NULL && ! info->shared)
+ if (t == NULL && info->executable)
{
struct bfd_elf_version_tree **pp;
int version_index;
--- include/bfdlink.h.jj 2003-05-23 10:18:54.000000000 -0400
+++ include/bfdlink.h 2003-05-28 03:15:38.000000000 -0400
@@ -291,6 +291,12 @@ struct bfd_link_info
/* TRUE if relaxation is being finalized. */
unsigned int relax_finalizing: 1;
+ /* TRUE if generating a position independent executable. */
+ unsigned int pie: 1;
+
+ /* TRUE if generating an executable, position independent or not. */
+ unsigned int executable : 1;
+
/* Which symbols to strip. */
enum bfd_link_strip strip;
--- ld/emulparams/elf_i386.sh.jj 2002-03-07 14:52:39.000000000 -0500
+++ ld/emulparams/elf_i386.sh 2003-05-28 03:15:38.000000000 -0400
@@ -9,4 +9,5 @@ MACHINE=
NOP=0x90909090
TEMPLATE_NAME=elf32
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
NO_SMALL_DATA=yes
--- ld/emulparams/elf64_ia64.sh.jj 2003-05-15 16:42:25.000000000 -0400
+++ ld/emulparams/elf64_ia64.sh 2003-05-28 03:15:38.000000000 -0400
@@ -16,6 +16,7 @@ fi
TEXT_START_ADDR="0x4000000000000000"
DATA_ADDR="0x6000000000000000 + (. & (${MAXPAGESIZE} - 1))"
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
NOP=0x00300000010070000002000001000400 # a bundle full of nops
OTHER_GOT_SECTIONS="
.IA_64.pltoff ${RELOCATING-0} : { *(.IA_64.pltoff) }"
--- ld/emulparams/elf32ppc.sh.jj 2003-03-19 12:19:16.000000000 -0500
+++ ld/emulparams/elf32ppc.sh 2003-05-28 03:15:38.000000000 -0400
@@ -4,6 +4,7 @@
TEMPLATE_NAME=elf32
EXTRA_EM_FILE=ppc32elf
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
SCRIPT_NAME=elf
OUTPUT_FORMAT="elf32-powerpc"
TEXT_START_ADDR=0x01800000
--- ld/emulparams/elf64ppc.sh.jj 2003-01-21 13:21:34.000000000 -0500
+++ ld/emulparams/elf64ppc.sh 2003-05-28 03:15:38.000000000 -0400
@@ -2,6 +2,7 @@ TEMPLATE_NAME=elf32
EXTRA_EM_FILE=ppc64elf
ELFSIZE=64
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
SCRIPT_NAME=elf
OUTPUT_FORMAT="elf64-powerpc"
TEXT_START_ADDR=0x10000000
--- ld/emulparams/elf_x86_64.sh.jj 2003-03-19 12:19:16.000000000 -0500
+++ ld/emulparams/elf_x86_64.sh 2003-05-28 03:15:38.000000000 -0400
@@ -10,6 +10,7 @@ MACHINE=
NOP=0x90909090
TEMPLATE_NAME=elf32
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
NO_SMALL_DATA=yes
if [ "x${host}" = "x${target}" ]; then
--- ld/emulparams/elf_s390.sh.jj 2002-03-07 14:52:39.000000000 -0500
+++ ld/emulparams/elf_s390.sh 2003-05-28 03:15:38.000000000 -0400
@@ -8,3 +8,4 @@ MACHINE=
NOP=0x07070707
TEMPLATE_NAME=elf32
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
--- ld/emulparams/elf64_sparc.sh.jj 2003-03-19 12:19:16.000000000 -0500
+++ ld/emulparams/elf64_sparc.sh 2003-05-28 03:30:35.000000000 -0400
@@ -8,6 +8,7 @@ ARCH="sparc:v9"
MACHINE=
DATA_PLT=
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
NOP=0x01000000
NO_SMALL_DATA=yes
--- ld/emulparams/elf32_sparc.sh.jj 2002-03-07 14:52:39.000000000 -0500
+++ ld/emulparams/elf32_sparc.sh 2003-05-28 03:30:49.000000000 -0400
@@ -10,4 +10,5 @@ MACHINE=
TEMPLATE_NAME=elf32
DATA_PLT=
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
NO_SMALL_DATA=yes
--- ld/emulparams/elf64alpha.sh.jj 2003-03-19 12:19:16.000000000 -0500
+++ ld/emulparams/elf64alpha.sh 2003-05-28 03:31:11.000000000 -0400
@@ -11,6 +11,7 @@ NONPAGED_TEXT_START_ADDR="0x120000000"
ARCH=alpha
MACHINE=
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
DATA_PLT=
# Note that the number is always big-endian, thus we have to
# reverse the digit string.
--- ld/emulparams/elf64_s390.sh.jj 2003-03-19 12:19:16.000000000 -0500
+++ ld/emulparams/elf64_s390.sh 2003-05-28 03:31:25.000000000 -0400
@@ -9,6 +9,7 @@ MACHINE=
NOP=0x07070707
TEMPLATE_NAME=elf32
GENERATE_SHLIB_SCRIPT=yes
+GENERATE_PIE_SCRIPT=yes
# Treat a host that matches the target with the possible exception of "x"
# in the name as if it were native.
--- ld/emultempl/elf32.em.jj 2003-05-28 03:03:45.000000000 -0400
+++ ld/emultempl/elf32.em 2003-05-28 05:37:00.000000000 -0400
@@ -643,7 +643,7 @@ gld${EMULATION_NAME}_after_open ()
struct bfd_link_needed_list *needed, *l;
/* We only need to worry about this when doing a final link. */
- if (link_info.relocateable || link_info.shared)
+ if (link_info.relocateable || !link_info.executable)
return;
/* Get the list of files which appear in DT_NEEDED entries in
@@ -1181,7 +1181,7 @@ gld${EMULATION_NAME}_place_orphan (file,
/* If this is a final link, then always put .gnu.warning.SYMBOL
sections into the .text section to get them out of the way. */
- if (! link_info.shared
+ if (link_info.executable
&& ! link_info.relocateable
&& strncmp (secname, ".gnu.warning.", sizeof ".gnu.warning." - 1) == 0
&& hold_text.os != NULL)
@@ -1475,6 +1475,14 @@ if cmp -s ldscripts/${EMULATION_NAME}.x
echo ' ; else if (!config.magic_demand_paged) return' >> e${EMULATION_NAME}.c
sed $sc ldscripts/${EMULATION_NAME}.xn >> e${EMULATION_NAME}.c
fi
+if test -n "$GENERATE_PIE_SCRIPT" ; then
+if test -n "$GENERATE_COMBRELOC_SCRIPT" ; then
+echo ' ; else if (link_info.pie && link_info.combreloc) return' >> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xdc >> e${EMULATION_NAME}.c
+fi
+echo ' ; else if (link_info.pie) return' >> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xd >> e${EMULATION_NAME}.c
+fi
if test -n "$GENERATE_SHLIB_SCRIPT" ; then
if test -n "$GENERATE_COMBRELOC_SCRIPT" ; then
echo ' ; else if (link_info.shared && link_info.combreloc) return' >> e${EMULATION_NAME}.c
@@ -1512,6 +1520,18 @@ cat >>e${EMULATION_NAME}.c <<EOF
return "ldscripts/${EMULATION_NAME}.xn";
EOF
fi
+if test -n "$GENERATE_PIE_SCRIPT" ; then
+if test -n "$GENERATE_COMBRELOC_SCRIPT" ; then
+cat >>e${EMULATION_NAME}.c <<EOF
+ else if (link_info.pie && link_info.combreloc)
+ return "ldscripts/${EMULATION_NAME}.xdc";
+EOF
+fi
+cat >>e${EMULATION_NAME}.c <<EOF
+ else if (link_info.pie)
+ return "ldscripts/${EMULATION_NAME}.xd";
+EOF
+fi
if test -n "$GENERATE_SHLIB_SCRIPT" ; then
if test -n "$GENERATE_COMBRELOC_SCRIPT" ; then
cat >>e${EMULATION_NAME}.c <<EOF
--- ld/scripttempl/elf.sc.jj 2003-05-28 03:03:45.000000000 -0400
+++ ld/scripttempl/elf.sc 2003-05-28 03:15:38.000000000 -0400
@@ -180,8 +180,9 @@ ${RELOCATING- /* For some reason, the So
SECTIONS
{
/* Read-only sections, merged into text segment: */
- ${CREATE_SHLIB-${RELOCATING+. = ${TEXT_BASE_ADDRESS};}}
+ ${CREATE_SHLIB-${CREATE_PIE-${RELOCATING+. = ${TEXT_BASE_ADDRESS};}}}
${CREATE_SHLIB+${RELOCATING+. = ${SHLIB_TEXT_START_ADDR:-0} + SIZEOF_HEADERS;}}
+ ${CREATE_PIE+${RELOCATING+. = ${SHLIB_TEXT_START_ADDR:-0} + SIZEOF_HEADERS;}}
${CREATE_SHLIB-${INTERP}}
${INITIAL_READONLY_SECTIONS}
${TEXT_DYNAMIC+${DYNAMIC}}
--- ld/lexsup.c.jj 2003-05-15 16:42:25.000000000 -0400
+++ ld/lexsup.c 2003-05-28 03:15:38.000000000 -0400
@@ -139,6 +139,7 @@ int parsing_defsym = 0;
#define OPTION_NO_STRIP_DISCARDED (OPTION_STRIP_DISCARDED + 1)
#define OPTION_ACCEPT_UNKNOWN_INPUT_ARCH (OPTION_NO_STRIP_DISCARDED + 1)
#define OPTION_NO_ACCEPT_UNKNOWN_INPUT_ARCH (OPTION_ACCEPT_UNKNOWN_INPUT_ARCH + 1)
+#define OPTION_PIE (OPTION_NO_ACCEPT_UNKNOWN_INPUT_ARCH + 1)
/* The long options. This structure is used for both the option
parsing and the help text. */
@@ -373,6 +374,10 @@ static const struct ld_option ld_options
'\0', NULL, N_("Create a shared library"), ONE_DASH },
{ {"Bshareable", no_argument, NULL, OPTION_SHARED }, /* FreeBSD. */
'\0', NULL, NULL, ONE_DASH },
+ { {"pie", no_argument, NULL, OPTION_PIE},
+ '\0', NULL, N_("Create a position independent executable"), ONE_DASH },
+ { {"pic-executable", no_argument, NULL, OPTION_PIE},
+ '\0', NULL, NULL, TWO_DASHES },
{ {"sort-common", no_argument, NULL, OPTION_SORT_COMMON},
'\0', NULL, N_("Sort common symbols by size"), TWO_DASHES },
{ {"sort_common", no_argument, NULL, OPTION_SORT_COMMON},
@@ -958,6 +961,15 @@ parse_args (argc, argv)
else
einfo (_("%P%F: -shared not supported\n"));
break;
+ case OPTION_PIE:
+ if (config.has_shared)
+ {
+ link_info.shared = TRUE;
+ link_info.pie = TRUE;
+ }
+ else
+ einfo (_("%P%F: -pie not supported\n"));
+ break;
case 'h': /* Used on Solaris. */
case OPTION_SONAME:
command_line.soname = optarg;
--- ld/genscripts.sh.jj 2003-03-19 12:19:16.000000000 -0500
+++ ld/genscripts.sh 2003-05-28 03:15:38.000000000 -0400
@@ -227,6 +227,31 @@ if test -n "$GENERATE_SHLIB_SCRIPT"; the
rm -f ${COMBRELOC}
COMBRELOC=
fi
+ unset CREATE_SHLIB
+fi
+
+if test -n "$GENERATE_PIE_SCRIPT"; then
+ LD_FLAG=pie
+ DATA_ALIGNMENT=${DATA_ALIGNMENT_s-${DATA_ALIGNMENT_}}
+ CREATE_PIE=" "
+ # Note that TEXT_START_ADDR is set to NONPAGED_TEXT_START_ADDR.
+ (
+ echo "/* Script for ld -pie: link position independent executable */"
+ . ${srcdir}/emulparams/${EMULATION_NAME}.sh
+ . ${srcdir}/scripttempl/${SCRIPT_NAME}.sc
+ ) | sed -e '/^ *$/d;s/[ ]*$//' > ldscripts/${EMULATION_NAME}.xd
+ if test -n "$GENERATE_COMBRELOC_SCRIPT"; then
+ LD_FLAG=cpie
+ DATA_ALIGNMENT=${DATA_ALIGNMENT_sc-${DATA_ALIGNMENT}}
+ COMBRELOC=ldscripts/${EMULATION_NAME}.xc.tmp
+ ( echo "/* Script for -pie -z combreloc: position independent executable, combine & sort relocs */"
+ . ${srcdir}/emulparams/${EMULATION_NAME}.sh
+ . ${srcdir}/scripttempl/${SCRIPT_NAME}.sc
+ ) | sed -e '/^ *$/d;s/[ ]*$//' > ldscripts/${EMULATION_NAME}.xdc
+ rm -f ${COMBRELOC}
+ COMBRELOC=
+ fi
+ unset CREATE_PIE
fi
case " $EMULATION_LIBPATH " in
--- ld/ldmain.c.jj 2003-05-15 16:42:25.000000000 -0400
+++ ld/ldmain.c 2003-05-28 03:15:38.000000000 -0400
@@ -291,6 +291,8 @@ main (argc, argv)
link_info.emitrelocations = FALSE;
link_info.task_link = FALSE;
link_info.shared = FALSE;
+ link_info.pie = FALSE;
+ link_info.executable = FALSE;
link_info.symbolic = FALSE;
link_info.export_dynamic = FALSE;
link_info.static_link = FALSE;
@@ -368,6 +370,9 @@ main (argc, argv)
einfo (_("%P%F: -f may not be used without -shared\n"));
}
+ if (! link_info.shared || link_info.pie)
+ link_info.executable = TRUE;
+
/* Treat ld -r -s as ld -r -S -x (i.e., strip all local symbols). I
don't see how else this can be handled, since in this case we
must preserve all externally visible symbols. */
--- ld/ld.texinfo.jj 2003-05-05 17:46:49.000000000 -0400
+++ ld/ld.texinfo 2003-05-29 07:35:25.000000000 -0400
@@ -1209,6 +1209,18 @@ command @code{OUTPUT_FORMAT} can also sp
this option overrides it. @xref{BFD}.
@end ifclear
+@kindex -pie
+@kindex --pic-executable
+@item -pie
+@itemx --pic-executable
+@cindex position independent executables
+Create a position independent executable. This is currently only supported on
+ELF platforms. Position independent executables are similar to shared
+libraries in that they are relocated by the dynamic linker to the virtual
+address OS chooses for them (which can varry between invocations), like
+normal dynamically linked executables they can be executed and symbols
+defined in the executable cannot be overridden by shared libraries.
+
@kindex -qmagic
@item -qmagic
This option is ignored for Linux compatibility.
Jakub
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