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.
Merge roland/nptl-hppa to master, update and test for hppa-linux-gnu.
This commit squashes and commits the work done by Roland McGrath on
roland/nptl-hppa to migrate hppa to the new non-addon NPTL. Some
additional tweaks were required for tcb-offsets.sym to work correctly
along with clone.S (unique to hppa).
2003-12-18 Carlos O'Donell <carlos@baldric.uwo.ca>
* sysdeps/unix/sysv/linux/hppa/clone.S (__clone) [PIC]: Save PIC,
reload PIC if we need to call __syscall_error, cleanup asm.
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.
2000-10-14 Ulrich Drepper <drepper@redhat.com>
* math/libm-test.inc (frexp_test): Add L suffix also to parameters.
(hypot_test): Likewise.
* sysdeps/generic/printf_fphex.c: Compute width of decimal point
string correctly. Handle padding correctly.
* sysdeps/ia64/fpu/printf_fphex.c: Use sizeof in _itowa parameters
correctly.
* sysdeps/ieee754/ldbl-128/printf_fphex.c: Likewise.
* sysdeps/ieee754/ldbl-96/printf_fphex.c: Likewise.
2000-10-12 Alan Modra <alan@linuxcare.com.au>
* FAQ.in: Add --start-group and --end-group.
2000-10-12 Alan Modra <alan@linuxcare.com.au>
* malloc/memusage.c: Conditionalize stack usage calculation on
stack direction.
2000-10-12 Alan Modra <alan@linuxcare.com.au>
* config.h.in: Add ASM_LINE_SEP.
* configure.in: Add test for comment and line separators.
* include/libc-symbols.h: Define and use ASM_LINE_SEP, and add tabs to
placate some hppa assemblers.
* sysdeps/hppa/sysdep.h: Likewise.
* sysdeps/gnu/siglist.c: Insert \n and \t into inline asm.
* sysdeps/unix/sysv/linux/errlist.c: Likewise.
2000-10-12 David Huggins-Daines <dhd@linuxcare.com>
* sysdeps/unix/sysv/linux/Makefile: Include <bits/initspin> in
$(sysdep_headers).
* sysdeps/unix/sysv/linux/bits/initspin.h: Dummy version for
non-threaded platforms.
2000-10-12 David Huggins-Daines <dhd@linuxcare.com>
* configure.in: Add definitions for hppa.
* elf/elf.h: Add PLABEL32 relocation for hppa ELF32, comments
for IPLT and EPLT relocations.
* shlib-versions: Version symbol definitions for hppa-linux.
* sysdeps/unix/sysv/linux/configure.in: Define $arch_minimum_kernel
for hppa.
2000-10-12 David Huggins-Daines <dhd@linuxcare.com>
* sysdeps/hppa/Makefile: New file.
* sysdeps/hppa/Versions: New file.
* sysdeps/hppa/setjmp.S: New file.
* sysdeps/hppa/__longjmp.S: New file.
* sysdeps/hppa/bits/setjmp.h: New file.
* sysdeps/hppa/frame.h: New file.
* sysdeps/hppa/add_n.s: Don't use %r19 (linkage table pointer).
* sysdeps/hppa/sub_n.s: Likewise.
* sysdeps/hppa/lshift.s: Likewise.
* sysdeps/hppa/rshift.s: Likewise.
* sysdeps/hppa/udiv_qrnnd.s: Likewise.
* sysdeps/hppa/hppa1.1/addmul_1.s: Likewise.
* sysdeps/hppa/hppa1.1/submul_1.s: Likewise.
* sysdeps/hppa/hppa1.1/mul_1.s: Likewise.
* sysdeps/hppa/hppa1.1/udiv_qrnnd.s: Likewise.
* sysdeps/hppa/dl-machine.h: New file.
* sysdeps/hppa/dl-fptr.c: New file (note that this is almost
identical to the IA-64 one).
* sysdeps/hppa/dl-lookupcfg.h: Likewise.
* sysdeps/hppa/dl-symaddr.c: Likewise.
* sysdeps/hppa/elf/initfini.c: New file.
* sysdeps/hppa/elf/start.S: New file.
* sysdeps/hppa/fpu/bits/fenv.h: New file.
* sysdeps/hppa/fpu/fclrexcpt.c: New file.
* sysdeps/hppa/fpu/fedisblxcpt.c: New file.
* sysdeps/hppa/fpu/feenablxcpt.c: New file.
* sysdeps/hppa/fpu/fegetenv.c: New file.
* sysdeps/hppa/fpu/fegetexcept.c: New file.
* sysdeps/hppa/fpu/fegetround.c: New file.
* sysdeps/hppa/fpu/feholdexcpt.c: New file.
* sysdeps/hppa/fpu/fesetenv.c: New file.
* sysdeps/hppa/fpu/fesetround.c: New file.
* sysdeps/hppa/fpu/feupdateenv.c: New file.
* sysdeps/hppa/fpu/fegetexcptflg.c: New file.
* sysdeps/hppa/fpu/fraiseexcpt.c: New file.
* sysdeps/hppa/fpu/fsetexcptflg.c: New file.
* sysdeps/hppa/fpu/ftestexcept.c: New file.
* sysdeps/unix/sysv/linux/hppa/Makefile: New file.
* sysdeps/unix/sysv/linux/hppa/Versions: New file.
* sysdeps/unix/sysv/linux/hppa/syscalls.list: New file.
* sysdeps/unix/sysv/linux/hppa/sysdep.c: New file.
* sysdeps/unix/sysv/linux/hppa/sysdep.h: New file.
* sysdeps/unix/sysv/linux/hppa/bits/fcntl.h: New file.
* sysdeps/unix/sysv/linux/hppa/bits/ioctls.h: New file.
* sysdeps/unix/sysv/linux/hppa/bits/mman.h: New file.
* sysdeps/unix/sysv/linux/hppa/bits/sigaction.h: New file.
* sysdeps/unix/sysv/linux/hppa/bits/signum.h: New file.
* sysdeps/unix/sysv/linux/hppa/brk.c: New file.
* sysdeps/unix/sysv/linux/hppa/clone.S: New file.
* sysdeps/unix/sysv/linux/hppa/socket.S: New file.
* sysdeps/unix/sysv/linux/hppa/syscall.S: New file.
* sysdeps/unix/sysv/linux/hppa/setrlimit.c: New file.
* sysdeps/unix/sysv/linux/hppa/getrlimit.c: New file.
* sysdeps/unix/sysv/linux/hppa/getrlimit64.c: New file.
* sysdeps/unix/sysv/linux/hppa/kernel_sigaction.h: New file.
* sysdeps/unix/sysv/linux/hppa/kernel_stat.h: New file.
* sysdeps/unix/sysv/linux/hppa/mmap.c: New file.
* sysdeps/unix/sysv/linux/hppa/profil-counter.h: New file.
* sysdeps/unix/sysv/linux/hppa/procfs.h: New file.
* sysdeps/unix/sysv/linux/hppa/ucontext.h: New file.
* sysdeps/unix/sysv/linux/hppa/umount.c: New file.
2000-10-12 Alan Modra <alan@linuxcare.com.au>
* sysdeps/hppa/hppa1.1/Implies: New file.
* sysdeps/hppa/memusage.h: New file.
