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Re: [patch 08/15] PIE: Base functionality
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: gdb-patches at sourceware dot org
- Cc: Tom Tromey <tromey at redhat dot com>
- Date: Thu, 14 Jan 2010 21:57:19 +0100
- Subject: Re: [patch 08/15] PIE: Base functionality
On Mon, 09 Nov 2009 21:59:27 +0100, Jan Kratochvil wrote:
> Patch does not try to make `-fPIE -pie -static' working as on non-embedded
> GNU/Linux targets it has no use and it does not even build for me on
> fedora12.x86_64.
> /usr/bin/ld: /usr/lib/gcc/x86_64-redhat-linux/4.4.2/crtbeginT.o: relocation R_X86_64_32 against `__DTOR_END__' can not be used when
> making a shared object; recompile with -fPIC
> Left there some existing embedded static PIE support intact
> (->svr4_static_exec_displacement).
Later tried such executable using this x86_64 source and:
gcc -o a -nostdlib a.S -Wall -g -shared
#include <asm/unistd.h>
.text
.globl _start
_start:
nop
mov $__NR_pause, %eax
syscall
mov $__NR_exit_group, %eax
mov $42, %rdi
syscall
-fPIC and -fPIE have no meaning for .S source and -pie created .interp despite
-nostdlib so -shared acts as -pie creating ET_DYN in this case.
And svr4_static_exec_displacement (former svr4_relocate_main_executable) is
really broken for attaching to such program (FSF GDB before this patchset
relocated the executable by non-PAGE_SIZE offset according to the current PC).
But with this patch this function is no longer used, only in a case when
target_auxv_search fails to find AT_ENTRY. Such search succeeds even for core
file thanks for the NT_AUXV NOTE. So I have no cases when
svr4_static_exec_displacement can be used, probably in some embedded situation
so this code should at least not regress there.
On Wed, 11 Nov 2009 18:19:21 +0100, Tom Tromey wrote:
> >>>>> "Jan" == Jan Kratochvil <jan.kratochvil@redhat.com> writes:
>
> Jan> gdb/
> Jan> * solib-svr4.c (svr4_relocate_main_executable): Move the static exec
> Jan> code part to ...
> Jan> (svr4_static_exec_displacement): ... a new function.
> Jan> (svr4_exec_displacement): New function.
> Jan> (svr4_relocate_main_executable): Call svr4_exec_displacement. Allocate
> Jan> new_offsets using alloca now. Remove variable old_chain and changed.
> Jan> Call objfile_relocate unconditionally now.
> Jan> * symfile.c (syms_from_objfile): Relocate even MAINLINE objfiles.
>
> Ok.
Checked-in.
Thanks,
Jan
http://sourceware.org/ml/gdb-cvs/2010-01/msg00120.html
--- src/gdb/ChangeLog 2010/01/14 18:58:57 1.11246
+++ src/gdb/ChangeLog 2010/01/14 20:48:25 1.11247
@@ -1,3 +1,13 @@
+2010-01-14 Jan Kratochvil <jan.kratochvil@redhat.com>
+
+ * solib-svr4.c (svr4_relocate_main_executable): Move the static exec
+ code part to ...
+ (svr4_static_exec_displacement): ... a new function.
+ (svr4_exec_displacement): New function.
+ (svr4_relocate_main_executable): Call svr4_exec_displacement. Allocate
+ new_offsets using alloca now. Remove variable old_chain and changed.
+ Call objfile_relocate unconditionally now.
+
2010-01-14 Doug Evans <dje@google.com>
* gdbtypes.c (arch_flags_type): Fix comment.
--- src/gdb/solib-svr4.c 2010/01/08 22:52:03 1.110
+++ src/gdb/solib-svr4.c 2010/01/14 20:48:26 1.111
@@ -1535,111 +1535,119 @@
{
}
-/* Relocate the main executable. This function should be called upon
- stopping the inferior process at the entry point to the program.
- The entry point from BFD is compared to the PC and if they are
- different, the main executable is relocated by the proper amount.
+/* Decide if the objfile needs to be relocated. As indicated above,
+ we will only be here when execution is stopped at the beginning
+ of the program. Relocation is necessary if the address at which
+ we are presently stopped differs from the start address stored in
+ the executable AND there's no interpreter section. The condition
+ regarding the interpreter section is very important because if
+ there *is* an interpreter section, execution will begin there
+ instead. When there is an interpreter section, the start address
+ is (presumably) used by the interpreter at some point to start
+ execution of the program.
+
+ If there is an interpreter, it is normal for it to be set to an
+ arbitrary address at the outset. The job of finding it is
+ handled in enable_break().
+
+ So, to summarize, relocations are necessary when there is no
+ interpreter section and the start address obtained from the
+ executable is different from the address at which GDB is
+ currently stopped.
- As written it will only attempt to relocate executables which
- lack interpreter sections. It seems likely that only dynamic
- linker executables will get relocated, though it should work
- properly for a position-independent static executable as well. */
+ [ The astute reader will note that we also test to make sure that
+ the executable in question has the DYNAMIC flag set. It is my
+ opinion that this test is unnecessary (undesirable even). It
+ was added to avoid inadvertent relocation of an executable
+ whose e_type member in the ELF header is not ET_DYN. There may
+ be a time in the future when it is desirable to do relocations
+ on other types of files as well in which case this condition
+ should either be removed or modified to accomodate the new file
+ type. (E.g, an ET_EXEC executable which has been built to be
+ position-independent could safely be relocated by the OS if
+ desired. It is true that this violates the ABI, but the ABI
+ has been known to be bent from time to time.) - Kevin, Nov 2000. ]
+ */
-static void
-svr4_relocate_main_executable (void)
+static CORE_ADDR
+svr4_static_exec_displacement (void)
{
asection *interp_sect;
struct regcache *regcache
= get_thread_arch_regcache (inferior_ptid, target_gdbarch);
CORE_ADDR pc = regcache_read_pc (regcache);
- /* Decide if the objfile needs to be relocated. As indicated above,
- we will only be here when execution is stopped at the beginning
- of the program. Relocation is necessary if the address at which
- we are presently stopped differs from the start address stored in
- the executable AND there's no interpreter section. The condition
- regarding the interpreter section is very important because if
- there *is* an interpreter section, execution will begin there
- instead. When there is an interpreter section, the start address
- is (presumably) used by the interpreter at some point to start
- execution of the program.
-
- If there is an interpreter, it is normal for it to be set to an
- arbitrary address at the outset. The job of finding it is
- handled in enable_break().
-
- So, to summarize, relocations are necessary when there is no
- interpreter section and the start address obtained from the
- executable is different from the address at which GDB is
- currently stopped.
-
- [ The astute reader will note that we also test to make sure that
- the executable in question has the DYNAMIC flag set. It is my
- opinion that this test is unnecessary (undesirable even). It
- was added to avoid inadvertent relocation of an executable
- whose e_type member in the ELF header is not ET_DYN. There may
- be a time in the future when it is desirable to do relocations
- on other types of files as well in which case this condition
- should either be removed or modified to accomodate the new file
- type. (E.g, an ET_EXEC executable which has been built to be
- position-independent could safely be relocated by the OS if
- desired. It is true that this violates the ABI, but the ABI
- has been known to be bent from time to time.) - Kevin, Nov 2000. ]
- */
-
interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
if (interp_sect == NULL
&& (bfd_get_file_flags (exec_bfd) & DYNAMIC) != 0
&& (exec_entry_point (exec_bfd, &exec_ops) != pc))
+ return pc - exec_entry_point (exec_bfd, &exec_ops);
+
+ return 0;
+}
+
+/* We relocate all of the sections by the same amount. This
+ behavior is mandated by recent editions of the System V ABI.
+ According to the System V Application Binary Interface,
+ Edition 4.1, page 5-5:
+
+ ... Though the system chooses virtual addresses for
+ individual processes, it maintains the segments' relative
+ positions. Because position-independent code uses relative
+ addressesing between segments, the difference between
+ virtual addresses in memory must match the difference
+ between virtual addresses in the file. The difference
+ between the virtual address of any segment in memory and
+ the corresponding virtual address in the file is thus a
+ single constant value for any one executable or shared
+ object in a given process. This difference is the base
+ address. One use of the base address is to relocate the
+ memory image of the program during dynamic linking.
+
+ The same language also appears in Edition 4.0 of the System V
+ ABI and is left unspecified in some of the earlier editions. */
+
+static CORE_ADDR
+svr4_exec_displacement (void)
+{
+ int found;
+ CORE_ADDR entry_point;
+
+ if (exec_bfd == NULL)
+ return 0;
+
+ if (target_auxv_search (¤t_target, AT_ENTRY, &entry_point) == 1)
+ return entry_point - exec_entry_point (exec_bfd, ¤t_target);
+
+ return svr4_static_exec_displacement ();
+}
+
+/* Relocate the main executable. This function should be called upon
+ stopping the inferior process at the entry point to the program.
+ The entry point from BFD is compared to the AT_ENTRY of AUXV and if they are
+ different, the main executable is relocated by the proper amount. */
+
+static void
+svr4_relocate_main_executable (void)
+{
+ CORE_ADDR displacement = svr4_exec_displacement ();
+
+ /* Even if DISPLACEMENT is 0 still try to relocate it as this is a new
+ difference of in-memory vs. in-file addresses and we could already
+ relocate the executable at this function to improper address before. */
+
+ if (symfile_objfile)
{
- struct cleanup *old_chain;
struct section_offsets *new_offsets;
- int i, changed;
- CORE_ADDR displacement;
-
- /* It is necessary to relocate the objfile. The amount to
- relocate by is simply the address at which we are stopped
- minus the starting address from the executable.
-
- We relocate all of the sections by the same amount. This
- behavior is mandated by recent editions of the System V ABI.
- According to the System V Application Binary Interface,
- Edition 4.1, page 5-5:
-
- ... Though the system chooses virtual addresses for
- individual processes, it maintains the segments' relative
- positions. Because position-independent code uses relative
- addressesing between segments, the difference between
- virtual addresses in memory must match the difference
- between virtual addresses in the file. The difference
- between the virtual address of any segment in memory and
- the corresponding virtual address in the file is thus a
- single constant value for any one executable or shared
- object in a given process. This difference is the base
- address. One use of the base address is to relocate the
- memory image of the program during dynamic linking.
-
- The same language also appears in Edition 4.0 of the System V
- ABI and is left unspecified in some of the earlier editions. */
-
- displacement = pc - exec_entry_point (exec_bfd, &exec_ops);
- changed = 0;
-
- new_offsets = xcalloc (symfile_objfile->num_sections,
- sizeof (struct section_offsets));
- old_chain = make_cleanup (xfree, new_offsets);
+ int i;
- for (i = 0; i < symfile_objfile->num_sections; i++)
- {
- if (displacement != ANOFFSET (symfile_objfile->section_offsets, i))
- changed = 1;
- new_offsets->offsets[i] = displacement;
- }
+ new_offsets = alloca (symfile_objfile->num_sections
+ * sizeof (*new_offsets));
- if (changed)
- objfile_relocate (symfile_objfile, new_offsets);
+ for (i = 0; i < symfile_objfile->num_sections; i++)
+ new_offsets->offsets[i] = displacement;
- do_cleanups (old_chain);
+ objfile_relocate (symfile_objfile, new_offsets);
}
}
--- src/gdb/testsuite/ChangeLog 2010/01/14 08:03:37 1.2082
+++ src/gdb/testsuite/ChangeLog 2010/01/14 20:48:26 1.2083
@@ -1,3 +1,7 @@
+2010-01-14 Jan Kratochvil <jan.kratochvil@redhat.com>
+
+ * gdb.base/break-interp.exp: New file.
+
2010-01-13 Phil Muldoon <pmuldoon@redhat.com>
* gdb.python/py-value.exp (test_lazy_strings): Add lazy string test.
--- src/gdb/testsuite/gdb.base/break-interp.exp
+++ src/gdb/testsuite/gdb.base/break-interp.exp 2010-01-14 20:48:46.141738000 +0000
@@ -0,0 +1,413 @@
+# Copyright 2010 Free Software Foundation, Inc.
+
+# 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; either version 3 of the License, or
+# (at your option) any later version.
+#
+# 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, see <http://www.gnu.org/licenses/>.
+
+# This test only works on GNU/Linux.
+if { ![isnative] || [is_remote host] || ![istarget *-linux*] } {
+ continue
+}
+
+set test "break-interp"
+set binprefix ${objdir}/${subdir}/${test}
+# Only to get the $interp_system name.
+set srcfile_test "start.c"
+set binfile_test ${test}-test
+set srcfile "start.c"
+if {[build_executable ${test}.exp $binfile_test ${srcfile_test} {}] == -1} {
+ return -1
+}
+
+# Return the interpreter filename string.
+# Return "" if no interpreter was found.
+proc section_get {exec section} {
+ global objdir
+ global subdir
+ set tmp "${objdir}/${subdir}/break-interp.interp"
+ set objcopy_program [transform objcopy]
+
+ set command "exec $objcopy_program -O binary --set-section-flags $section=A --change-section-address $section=0 -j $section $exec $tmp"
+ verbose -log "command is $command"
+ set result [catch $command output]
+ verbose -log "result is $result"
+ verbose -log "output is $output"
+ if {$result == 1} {
+ return ""
+ }
+ set fi [open $tmp]
+ fconfigure $fi -translation binary
+ set data [read $fi]
+ close $fi
+ #file delete $tmp
+ # .interp has size $len + 1 but .gnu_debuglink contains garbage after \000.
+ set len [string first \000 $data]
+ if {$len < 0} {
+ verbose -log "section $section not found"
+ return ""
+ }
+ set retval [string range $data 0 [expr $len - 1]]
+ verbose -log "section $section is <$retval>"
+ return $retval
+}
+
+# Note: The separate debug info file content build-id/crc32 are not verified
+# contrary to the GDB search algorithm skipping non-matching ones.
+proc system_debug_get {exec} {
+ global debug_root
+
+ set exec_build_id_debug [build_id_debug_filename_get $exec]
+ set debug_base "[file tail $exec].debug"
+ set exec_dir [file dirname $exec]
+
+ # isfile returns 1 even for symlinks to files.
+ set retval $debug_root/$exec_build_id_debug
+ if [file isfile $retval] {
+ return $retval
+ }
+ set retval $exec_dir/$debug_base
+ if [file isfile $retval] {
+ return $retval
+ }
+ set retval $exec_dir/.debug/$debug_base
+ if [file isfile $retval] {
+ return $retval
+ }
+ set retval $debug_root/$exec_dir/$debug_base
+ if [file isfile $retval] {
+ return $retval
+ }
+ return ""
+}
+
+gdb_exit
+gdb_start
+set debug_root ""
+set test "show debug-file-directory"
+gdb_test_multiple $test $test {
+ -re "The directory where separate debug symbols are searched for is \"(.*)\".\r\n$gdb_prompt $" {
+ set debug_root $expect_out(1,string)
+ }
+}
+
+set interp_system [section_get ${objdir}/${subdir}/$binfile_test .interp]
+set interp_system_debug [system_debug_get $interp_system]
+verbose -log "$interp_system has debug $interp_system_debug"
+
+proc prelinkNO_run {arg} {
+ set command "exec /usr/sbin/prelink -uN $arg"
+ verbose -log "command is $command"
+ set result [catch $command output]
+ verbose -log "result is $result"
+ verbose -log "output is $output"
+ return [list $result $output]
+}
+
+proc prelinkNO {arg {name {}}} {
+ if {$name == ""} {
+ set name [file tail $arg]
+ }
+ set test "unprelink $name"
+ set run [prelinkNO_run $arg]
+ set result [lindex $run 0]
+ set output [lindex $run 1]
+ if {$result == 0 && $output == ""} {
+ verbose -log "$name has been now unprelinked"
+ set run [prelinkNO_run $arg]
+ set result [lindex $run 0]
+ set output [lindex $run 1]
+ }
+ # Last line does miss the trailing \n.
+ if {$result == 1 && [regexp {^(/usr/sbin/prelink: [^ ]* does not have .gnu.prelink_undo section\n?)*$} $output]} {
+ pass $test
+ return 1
+ } else {
+ fail $test
+ return 0
+ }
+}
+
+proc prelinkYES {arg {name ""}} {
+ if {$name == ""} {
+ set name [file tail $arg]
+ }
+ set test "prelink $name"
+ set command "exec /usr/sbin/prelink -qNR --no-exec-shield $arg"
+ verbose -log "command is $command"
+ set result [catch $command output]
+ verbose -log "result is $result"
+ verbose -log "output is $output"
+ if {$result == 0 && $output == ""} {
+ pass $test
+ return 1
+ } else {
+ fail $test
+ return 0
+ }
+}
+
+# Resolve symlinks.
+proc symlink_resolve {file} {
+ set loop 0
+ while {[file type $file] == "link"} {
+ set target [file readlink $file]
+ if {[file pathtype $target] == "relative"} {
+ set src2 [file dirname $file]/$target
+ } else {
+ set src2 $target
+ }
+ verbose -log "Resolved symlink $file targetting $target as $src2"
+ set file $src2
+
+ set loop [expr $loop + 1]
+ if {$loop > 30} {
+ fail "Looping symlink resolution for $file"
+ return ""
+ }
+ }
+ return $file
+}
+
+proc copy {src dest} {
+ set src [symlink_resolve $src]
+ # Test name would contain build-id hash for symlink-unresolved $src.
+ set test "copy [file tail $src] to [file tail $dest]"
+ set command "file copy -force $src $dest"
+ verbose -log "command is $command"
+ if [catch $command] {
+ fail $test
+ return 0
+ } else {
+ pass $test
+ return 1
+ }
+}
+
+proc strip_debug {dest} {
+ set test "strip [file tail $dest]"
+ set strip_program [transform strip]
+ set command "exec $strip_program --strip-debug $dest"
+ verbose -log "command is $command"
+ if [catch $command] {
+ fail $test
+ return 0
+ } else {
+ pass $test
+ return 1
+ }
+}
+
+# `runto' does not check we stopped really at the function we specified.
+proc reach {func command} {
+ global gdb_prompt
+
+ if [gdb_breakpoint $func allow-pending] {
+ set test "reach $func"
+ gdb_test_multiple $command $test {
+ -re "Breakpoint \[0-9\]+, $func \\(.*\\) at .*:\[0-9\]+\r\n.*$gdb_prompt $" {
+ pass $test
+ }
+ -re "Breakpoint \[0-9\]+, \[0-9xa-f\]+ in $func \\(\\)( from .*)?\r\n$gdb_prompt $" {
+ pass $test
+ }
+ }
+ }
+}
+
+proc test_ld {file ifmain} {
+ global srcdir subdir gdb_prompt
+
+ # First test normal `file'-command loaded $FILE with symbols.
+
+ gdb_exit
+ gdb_start
+ # Clear it to never find any separate debug infos in $debug_root.
+ gdb_test "set debug-file-directory"
+ gdb_reinitialize_dir $srcdir/$subdir
+ gdb_load $file
+
+ reach "dl_main" run
+ if $ifmain {
+ reach "main" continue
+ }
+}
+
+# Create separate binaries for each testcase - to make the possible reported
+# problem reproducible after the whole test run finishes.
+
+set old_ldprefix $pf_prefix
+foreach ldprelink {NO YES} {
+ foreach ldsepdebug {NO IN SEP} {
+ # Skip running the ldsepdebug test if we do not have system separate
+ # debug info available.
+ if {$interp_system_debug == "" && $ldsepdebug == "SEP"} {
+ continue
+ }
+
+ set ldname "LDprelink${ldprelink}debug${ldsepdebug}"
+ set interp $binprefix-$ldname
+
+ # prelink needs to always prelink all the dependencies to do any file
+ # modifications of its files. ld.so also needs all the dependencies to
+ # be prelinked to omit the relocation process. In-memory file offsets
+ # are not dependent whether ld.so went the prelink way or through the
+ # relocation process.
+ #
+ # For GDB we are not interested whether prelink succeeds as it is
+ # transparent to GDB. GDB is being tested for differences of file
+ # offsets vs. in-memory offsets. So we have to prelink even ld.so for
+ # the BIN modification to happen but we need to restore the original
+ # possibly unprelinked ld.so to test all the combinations for GDB.
+ set interp_saved ${interp}-saved
+
+ set pf_prefix $old_ldprefix
+ lappend pf_prefix "$ldname:"
+
+ if {$ldsepdebug == "NO"} {
+ copy $interp_system $interp
+ # Never call strip-debug before unprelink:
+ # prelink: ...: Section .note.gnu.build-id created after prelinking
+ if ![prelinkNO $interp] {
+ continue
+ }
+ strip_debug $interp
+ } elseif {$ldsepdebug == "IN" && $interp_system_debug == ""} {
+ copy $interp_system $interp
+ } elseif {$ldsepdebug == "IN" && $interp_system_debug != ""} {
+ copy $interp_system $interp
+ copy $interp_system_debug "${interp}.debug"
+ # eu-unstrip: DWARF data in '...' not adjusted for prelinking bias; consider prelink -u
+ if {![prelinkNO $interp] || ![prelinkNO "${interp}.debug"]} {
+ continue
+ }
+ set test "eu-unstrip unprelinked:[file tail $interp_system] + [file tail $interp_system_debug] to [file tail $interp]"
+ set command "exec eu-unstrip -o $interp $interp ${interp}.debug"
+ verbose -log "command is $command"
+ if [catch $command] {
+ setup_xfail *-*-*
+ fail $test
+ continue
+ } else {
+ pass $test
+ }
+ } elseif {$ldsepdebug == "SEP" && $interp_system_debug == ""} {
+ copy $interp_system $interp
+ # eu-unstrip: DWARF data in '...' not adjusted for prelinking bias; consider prelink -u
+ if ![prelinkNO $interp] {
+ continue
+ }
+ gdb_gnu_strip_debug $interp
+ } elseif {$ldsepdebug == "SEP" && $interp_system_debug != ""} {
+ copy $interp_system $interp
+ copy $interp_system_debug "${interp}.debug"
+ }
+
+ if {$ldsepdebug == "SEP"} {
+ if ![prelinkNO "${interp}.debug"] {
+ continue
+ }
+ } else {
+ file delete "${interp}.debug"
+ }
+
+ if ![prelink$ldprelink $interp] {
+ continue
+ }
+ test_ld $interp 0
+
+ if ![copy $interp $interp_saved] {
+ continue
+ }
+ set old_binprefix $pf_prefix
+ foreach binprelink {NO YES} {
+ foreach binsepdebug {NO IN SEP} {
+ foreach binpie {NO YES} {
+ # This combination is not possible, non-PIE (fixed address)
+ # binary cannot be prelinked to any (other) address.
+ if {$binprelink == "YES" && $binpie == "NO"} {
+ continue
+ }
+
+ set binname "BINprelink${binprelink}debug${binsepdebug}pie${binpie}"
+ set exec $binprefix-$binname
+ set dir ${exec}.d
+
+ set pf_prefix $old_binprefix
+ lappend pf_prefix "$binname:"
+
+ set opts "additional_flags=-Wl,--dynamic-linker,$interp,-rpath,$dir"
+ if {$binsepdebug != "NO"} {
+ lappend opts {debug}
+ }
+ if {$binpie == "YES"} {
+ lappend opts {additional_flags=-fPIE -pie}
+ }
+ if {[build_executable ${test}.exp [file tail $exec] $srcfile $opts] == -1} {
+ continue;
+ }
+ if {$binsepdebug == "SEP"} {
+ gdb_gnu_strip_debug $exec
+ # Just a sanity check. As gdb_gnu_strip_debug uses the
+ # "[file dirname $exec]/.debug/[file tail $exec].debug"
+ # variant delete the higher-priority exec.debug file.
+ file delete "$exec.debug"
+ }
+
+ # Supply a self-sufficent directory $dir with the required
+ # libraries. To make an executable properly prelinked all
+ # its dependencies on libraries must be also prelinked. If
+ # some of the system libraries is currently not prelinked
+ # we have no right to prelink (modify it) at its current
+ # system place.
+
+ file delete -force $dir
+ file mkdir $dir
+
+ set command "ldd $exec"
+ set result [catch "exec $command" output]
+ verbose -log "result of $command is $result"
+ verbose -log "output of $command is $output"
+ if {$result != 0 || $output == ""} {
+ fail $command
+ } else {
+ pass $command
+ }
+
+ # gdb testsuite will put there also needless -lm.
+ set test "$command output contains libc"
+ set libc [regexp -all -inline -line {^.* => (/[^ ]+).*$} $output]
+ if {[llength $libc] == 0} {
+ fail $test
+ } else {
+ pass $test
+ }
+
+ set dests {}
+ for {set i 1} {$i < [llength $libc]} {incr i 2} {
+ set abspath [lindex $libc $i]
+ set dest "$dir/[file tail $abspath]"
+ copy $abspath $dest
+ lappend dests $dest
+ }
+
+ if {[prelink$binprelink "--dynamic-linker=$interp --ld-library-path=$dir $exec $interp [concat $dests]" $exec]
+ && [copy $interp_saved $interp]} {
+ test_ld $exec 1
+ }
+ }
+ }
+ }
+
+ file delete $interp_saved
+ }
+}
+set pf_prefix $old_ldprefix