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6ccf769a17
On fedora rawhide, with test-case gdb.base/rtld-step.exp I get:
...
static-pie-static-libc.c: In function '_start':^M
static-pie-static-libc.c:1:22: error: \
implicit declaration of function '_exit' [-Wimplicit-function-declaration]^M
1 | void _start (void) { _exit (0); }^M
| ^~~~~^M
compiler exited with status 1
...
UNTESTED: gdb.base/rtld-step.exp: failed to compile \
(-static-pie not supported or static libc missing)
...
Fix this by adding the missing include.
Tested on aarch64-linux.
Approved-by: Kevin Buettner <kevinb@redhat.com>
150 lines
6.2 KiB
Plaintext
150 lines
6.2 KiB
Plaintext
# Copyright 2022-2024 Free Software Foundation, Inc.
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# Test stepping through a runtime loader / dynamic linker (RTLD):
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#
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# While it'd be nice to have a test which steps through an actual
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# runtime loader / dynamic linker, constructing such a test would be
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# non-portable; we would need to know implementation details such
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# as the names of some of the symbols and the order of calls to
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# various functions that implement the RTLD. So, instead, we'll use a
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# program which doesn't even pretend to implement this functionality,
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# but which will instead be invoked in the same fashion (for ELF
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# binaries anyway) as would be expected for an ELF-based RTLD.
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#
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# To that end, we have two programs, one which will pretend to be an
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# RTLD and the other which will be caused to use the pretend RTLD.
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#
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# When the main program is run, the pretend/fake RTLD is run instead,
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# due to it being specified as the ELF interpreter for the main
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# program. Within GDB, we then attempt to do some simple debugging
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# involving 'step', 'next', and 'finish'.
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# This test can't be run on targets lacking shared library support
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# or for non-ELF targets. (We're not really testing or building
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# shared libraries here, but having a RTLD implies having shared
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# libraries on the target.)
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require allow_shlib_tests is_elf_target
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# (Pretend) RTLD file names and flags:
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set rtld_basename ${::gdb_test_file_name}-rtld
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set srcfile_rtld ${srcdir}/${subdir}/${rtld_basename}.c
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set binfile_rtld [standard_output_file ${rtld_basename}]
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# Placing 'pie' in the flag list (for rtld_flags) doesn't work, but
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# using -static-pie -FPIE in additional_flags does. Apparently, when
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# 'pie' is listed, gdb_compile will (on Linux) use both -fPIE and
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# -pie. Testing shows that use of -pie creates a dynamically linked
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# executable when either a static or static-pie executable is desired
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# instead. (This is probably fragile.)
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#
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# While developing this code on Fedora Linux, it was found that (only)
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# the flags -static-pie -fPIE were needed for Fedora 35 through Fedora
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# 38. The source file rtld-step-rtld.c didn't need the _start()
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# function either. And, better still, it was possible to call
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# printf() to output progress messages in the pretend/fake RTLD.
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# Sadly, these output statements had to be removed in order to obtain
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# code which would work on other Linux distributions / releases.
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#
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# When testing against earlier versions of Fedora, RHEL 9, and
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# also Ubuntu 22.04, that short flag list didn't work. For these
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# linux releases, it was found that -nostdlib -lc were also required.
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# Due to the use of -nostdlib, a _start() function had to be added
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# to the RTLD code.
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#
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# Finally, on FreeBSD, it was found that in order to end up with a
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# statically linked executable, -static was also needed.
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# Unfortunately, when attempting to run the rtld-step-main under GDB
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# on FreeBSD 13.1, this message was/is encountered:
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#
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# ELF interpreter /path/to/rtld-step-rtld not found, error 22
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#
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# So, sadly, this test does not currently work on FreeBSD. If you try
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# to make it work on FreeBSD, you'll probably need to enable the
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# declarations for __progname and environ in rtld-step-rtld.c.
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#
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# If this test becomes broken at some point in the future, you might
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# try removing -static from the flags below as it is not needed for
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# Linux.
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#
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# Also, because the RTLD is static, you'll need static versions of
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# libc/glibc installed on your system. (A message such as "cannot
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# find -lc" is a clue that you're missing a static version of libc.)
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set rtld_flags [list debug additional_flags=[list -static-pie -fPIE \
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-nostdlib -static -lc]]
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if { ![gdb_can_simple_compile static-pie-static-libc \
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{
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#include <unistd.h>
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void _start (void) { _exit (0); }
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} \
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executable $rtld_flags] } {
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set reason "-static-pie not supported or static libc missing"
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untested "failed to compile ($reason)"
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return -1
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}
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# Main program file names and flags:
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set main_basename ${::gdb_test_file_name}-main
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set srcfile_main ${srcdir}/${subdir}/${main_basename}.c
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set binfile_main [standard_output_file ${main_basename}]
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set main_flags [list debug additional_flags="-Wl,--dynamic-linker=${binfile_rtld}"]
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# Compile pretend RTLD:
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if { [gdb_compile ${srcfile_rtld} ${binfile_rtld} executable $rtld_flags] != "" } {
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untested "failed to compile"
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return -1
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}
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# Compile main program:
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if { [gdb_compile ${srcfile_main} ${binfile_main} executable $main_flags] != "" } {
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untested "failed to compile"
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return -1
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}
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clean_restart ${binfile_main}
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if {![runto_main]} {
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return 0
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}
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# Running the command 'info sharedlibrary' should output a path to
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# the pretend/fake RTLD along with the address range. Check that
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# this path is present and, if so, extract the address range.
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gdb_test_multiple "info sharedlibrary" "" {
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-re -wrap "($hex)\[ \t\]+($hex)\[ \t\]+Yes\[ \t\]+$fullname_syntax$rtld_basename" {
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set rtld_lower $expect_out(1,string)
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set rtld_upper $expect_out(2,string)
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pass $gdb_test_name
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}
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}
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# Fetch PC value.
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set pc [get_hexadecimal_valueof "\$pc" 0]
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# Verify that PC is in the address range of the pretend/fake RTLD.
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gdb_assert { $rtld_lower <= $pc && $pc < $rtld_upper } "pc is in rtld"
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gdb_test "next" {bar \(\);} "next over foo 0"
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gdb_test "step" {bar \(\) at.*foo \(1\);.*} "step into bar"
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gdb_test "step" {baz \(.*?\);} "step into foo 1"
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gdb_test "finish" {Run till exit.*bar \(\).*baz.*} "finish out of foo 1"
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gdb_test "next" {foo \(2\);} "next over baz in bar"
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gdb_test "step" {baz \(.*?\);} "step into foo 2"
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gdb_test "next" "\}" "next over baz in foo"
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gdb_test "step" "bar \\(\\).*}" "step out of foo back into bar"
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gdb_continue_to_end
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