This patch implements a new posix_spawn{p} implementation for Linux. The main
difference is it uses the clone syscall directly with CLONE_VM and CLONE_VFORK
flags and a direct allocated stack. The new stack and start function solves
most the vfork limitation (possible parent clobber due stack spilling). The
remaning issue are related to signal handling:
1. That no signal handlers must run in child context, to avoid corrupt
parent's state.
2. Child must synchronize with parent to enforce stack deallocation and
to possible return execv issues.
The first one is solved by blocking all signals in child, even NPTL-internal
ones (SIGCANCEL and SIGSETXID). The second issue is done by a stack allocation
in parent and a synchronization with using a pipe or waitpid (in case or error).
The pipe has the advantage of allowing the child signal an exec error (checked
with new tst-spawn2 test).
There is an inherent race condition in pipe2 usage for architectures that do not
support the syscall directly. In such cases the a pipe plus fctnl is used
instead and it may lead to file descriptor leak in parent (as decribed by fcntl
documentation).
The child process stack is allocate with a mmap with MAP_STACK flag using
default architecture stack size. Although it is slower than use a stack buffer
from parent, it allows some slack for the compatibility code to run scripts
with no shebang (which may use a buffer with size depending of argument list
count).
Performance should be similar to the vfork default posix implementation and
way faster than fork path (vfork on mostly linux ports are basically
clone with CLONE_VM plus CLONE_VFORK). The only difference is the syscalls
required for the stack allocation/deallocation.
It fixes BZ#10354, BZ#14750, and BZ#18433.
Tested on i386, x86_64, powerpc64le, and aarch64.
[BZ #14750]
[BZ #10354]
[BZ #18433]
* include/sched.h (__clone): Add hidden prototype.
(__clone2): Likewise.
* include/unistd.h (__dup): Likewise.
* posix/Makefile (tests): Add tst-spawn2.
* posix/tst-spawn2.c: New file.
* sysdeps/posix/dup.c (__dup): Add hidden definition.
* sysdeps/unix/sysv/linux/aarch64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/alpha/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/arm/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/hppa/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/i386/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/ia64/clone2.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/m68k/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/microblaze/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/mips/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/nios2/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S (__clone):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S (__clone):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/sh/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/tile/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/x86_64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/nptl-signals.h
(____nptl_is_internal_signal): New function.
* sysdeps/unix/sysv/linux/spawni.c: New file.
2004-12-07 Kaz Kojima <kkojima@rr.iij4u.or.jp>
* sysdeps/unix/sysv/linux/sh/clone.S: Clear the frame pointer when
starting a new thread. Add support for NPTL where the PID is stored
at userlevel and needs to be reset when CLONE_THREAD is not used.
2003-02-07 Kaz Kojima <kkojima@rr.iij4u.or.jp>
* elf/tls-macros.h: Add non-PIC TLS macros and fix clobber list
for SH.
* sysdeps/unix/sysv/linux/sh/brk.c: Add SYSCALL_INST_PAD
after the trapa instruction.
* sysdeps/unix/sysv/linux/sh/clone.S (__clone): Add additional
parameters.
* sysdeps/unix/sysv/linux/sh/sh4/sysdep.h: New file.
(NEED_SYSCALL_INST_PAD): Define.
* sysdeps/unix/sysv/linux/sh/sys/user.h (start_thread): Undef to
avoid to use definition for the kernel.
* sysdeps/unix/sysv/linux/sh/sysdep.h (SYSCALL_ERROR_HANDLER):
Save and restore the frame pointer.
(SYSCALL_INST_PAD): Define.
(INLINE_SYSCALL): Make use of INTERNAL_SYSCALL.
(INTERNAL_SYSCALL): Make use of ERR parameter. Add SYSCALL_INST_PAD
after trapa instruction.
(INTERNAL_SYSCALL_DECL, INTERNAL_SYSCALL_ERRNO,
INTERNAL_SYSCALL_ERROR_P): Adjust accordingly.
2003-01-05 Kaz Kojima <kkojima@rr.iij4u.or.jp>
* sysdeps/unix/sysv/linux/sh/clone.S (__clone): Use
SYSCALL_ERROR_HANDLER.
* sysdeps/unix/sysv/linux/sh/pipe.S (__libc_pipe): Likewise.
* sysdeps/unix/sysv/linux/sh/socket.S (__socket): Likewise.
Add support for cancellation handling.
* sysdeps/unix/sysv/linux/sh/syscall.S (__syscall): Use
SYSCALL_ERROR_HANDLER.
* sysdeps/unix/sysv/linux/sh/vfork.S (__vfork): Likewise.
* sysdeps/unix/sysv/linux/sh/sysdep.h (PSEUDO): Likewise.
Add support for cancellation handling.
(SYSCALL_ERROR_HANDLER): Define PIC variants.
2001-07-06 Paul Eggert <eggert@twinsun.com>
* manual/argp.texi: Remove ignored LGPL copyright notice; it's
not appropriate for documentation anyway.
* manual/libc-texinfo.sh: "Library General Public License" ->
"Lesser General Public License".
2001-07-06 Andreas Jaeger <aj@suse.de>
* All files under GPL/LGPL version 2: Place under LGPL version
2.1.
2000-06-12 Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Yutaka Niibe <gniibe@chroot.org>
* sysdeps/sh/Dist: New file.
* sysdeps/sh/Implies: New file.
* sysdeps/sh/gmp-mparam.h: New file.
* sysdeps/sh/init-first.c: New file.
* sysdeps/sh/machine-gmon.h: New file.
* sysdeps/sh/memcpy.S: New file.
* sysdeps/sh/memprof.h: New file.
* sysdeps/sh/memset.S: New file.
* sysdeps/sh/sh3/__longjmp.S: New file.
* sysdeps/sh/sh3/bits/endian.h: New file.
* sysdeps/sh/sh3/bits/huge_val.h: New file.
* sysdeps/sh/sh3/bits/setjmp.h: New file.
* sysdeps/sh/sh3/bsd-_setjmp.S: New file.
* sysdeps/sh/sh3/bsd-setjmp.S: New file.
* sysdeps/sh/sh3/dl-machine.h: New file.
* sysdeps/sh/sh3/elf/initfini.c: New file.
* sysdeps/sh/sh3/elf/start.S: New file.
* sysdeps/sh/sh3/setjmp.S: New file.
* sysdeps/sh/sh3/sys/ucontext.h: New file.
* sysdeps/sh/sh4/__longjmp.S: New file.
* sysdeps/sh/sh4/bits/endian.h: New file.
* sysdeps/sh/sh4/bits/huge_val.h: New file.
* sysdeps/sh/sh4/bits/setjmp.h: New file.
* sysdeps/sh/sh4/bsd-_setjmp.S: New file.
* sysdeps/sh/sh4/bsd-setjmp.S: New file.
* sysdeps/sh/sh4/dl-machine.h: New file.
* sysdeps/sh/sh4/elf/initfini.c: New file.
* sysdeps/sh/sh4/elf/start.S: New file.
* sysdeps/sh/sh4/fpu/bits/fenv.h: New file.
* sysdeps/sh/sh4/fpu/bits/huge_val.h: New file.
* sysdeps/sh/sh4/fpu/bits/mathdef.h: New file.
* sysdeps/sh/sh4/fpu/fclrexcpt.c: New file.
* sysdeps/sh/sh4/fpu/fegetenv.c: New file.
* sysdeps/sh/sh4/fpu/fegetround.c: New file.
* sysdeps/sh/sh4/fpu/feholdexcpt.c: New file.
* sysdeps/sh/sh4/fpu/fesetenv.c: New file.
* sysdeps/sh/sh4/fpu/fesetround.c: New file.
* sysdeps/sh/sh4/fpu/fpu_control.h: New file.
* sysdeps/sh/sh4/fpu/fraiseexcpt.c: New file.
* sysdeps/sh/sh4/fpu/fsetexcptflg.c: New file.
* sysdeps/sh/sh4/fpu/ftestexcept.c: New file.
* sysdeps/sh/sh4/fpu/libm-test-ulps: New file.
* sysdeps/sh/sh4/setjmp.S: New file.
* sysdeps/sh/sh4/sys/ucontext.h: New file.
* sysdeps/sh/strlen.S: New file.
* sysdeps/sh/sysdep.h: New file.
* sysdeps/unix/sh/sysdep.S: New file.
* sysdeps/unix/sh/sysdep.h: New file.
* sysdeps/unix/sysv/linux/sh/Dist: New file.
* sysdeps/unix/sysv/linux/sh/Makefile: New file.
* sysdeps/unix/sysv/linux/sh/Versions: New file.
* sysdeps/unix/sysv/linux/sh/bits/mman.h: New file.
* sysdeps/unix/sysv/linux/sh/bits/resource.h: New file.
* sysdeps/unix/sysv/linux/sh/brk.c: New file.
* sysdeps/unix/sysv/linux/sh/chown.c: New file.
* sysdeps/unix/sysv/linux/sh/clone.S: New file.
* sysdeps/unix/sysv/linux/sh/fchown.c: New file.
* sysdeps/unix/sysv/linux/sh/fxstat.c: New file.
* sysdeps/unix/sysv/linux/sh/getegid.c: New file.
* sysdeps/unix/sysv/linux/sh/geteuid.c: New file.
* sysdeps/unix/sysv/linux/sh/getgroups.c: New file.
* sysdeps/unix/sysv/linux/sh/getresgid.c: New file.
* sysdeps/unix/sysv/linux/sh/getresuid.c: New file.
* sysdeps/unix/sysv/linux/sh/getrlimit.c: New file.
* sysdeps/unix/sysv/linux/sh/getrlimit64.c: New file.
* sysdeps/unix/sysv/linux/sh/getuid.c: New file.
* sysdeps/unix/sysv/linux/sh/lchown.c: New file.
* sysdeps/unix/sysv/linux/sh/lxstat.c: New file.
* sysdeps/unix/sysv/linux/sh/msgctl.c: New file.
* sysdeps/unix/sysv/linux/sh/oldgetrlimit64.c: New file.
* sysdeps/unix/sysv/linux/sh/pipe.S: New file.
* sysdeps/unix/sysv/linux/sh/profil-counter.h: New file.
* sysdeps/unix/sysv/linux/sh/semctl.c: New file.
* sysdeps/unix/sysv/linux/sh/setegid.c: New file.
* sysdeps/unix/sysv/linux/sh/seteuid.c: New file.
* sysdeps/unix/sysv/linux/sh/setfsgid.c: New file.
* sysdeps/unix/sysv/linux/sh/setfsuid.c: New file.
* sysdeps/unix/sysv/linux/sh/setgid.c: New file.
* sysdeps/unix/sysv/linux/sh/setgroups.c: New file.
* sysdeps/unix/sysv/linux/sh/setregid.c: New file.
* sysdeps/unix/sysv/linux/sh/setresgid.c: New file.
* sysdeps/unix/sysv/linux/sh/setresuid.c: New file.
* sysdeps/unix/sysv/linux/sh/setreuid.c: New file.
* sysdeps/unix/sysv/linux/sh/setrlimit.c: New file.
* sysdeps/unix/sysv/linux/sh/setuid.c: New file.
* sysdeps/unix/sysv/linux/sh/sh3/register-dump.h: New file.
* sysdeps/unix/sysv/linux/sh/sh4/register-dump.h: New file.
* sysdeps/unix/sysv/linux/sh/shmctl.c: New file.
* sysdeps/unix/sysv/linux/sh/sigcontextinfo.h: New file.
* sysdeps/unix/sysv/linux/sh/socket.S: New file.
* sysdeps/unix/sysv/linux/sh/sys/io.h: New file.
* sysdeps/unix/sysv/linux/sh/sys/ucontext.h: New file.
* sysdeps/unix/sysv/linux/sh/sys/user.h: New file.
* sysdeps/unix/sysv/linux/sh/syscalls.list: New file.
* sysdeps/unix/sysv/linux/sh/sysdep.S: New file.
* sysdeps/unix/sysv/linux/sh/sysdep.h: New file.
* sysdeps/unix/sysv/linux/sh/vfork.S: New file.
* sysdeps/unix/sysv/linux/sh/xstat.c: New file.