glibc/sysdeps/unix/sysv/linux/alpha/clone.S
Adhemerval Zanella 3f823e87cc Call exit directly in clone (BZ #21512)
On aarch64, alpha, arm, hppa, mips, nios2, powerpc, sh, sparc, tile,
and x86_64 the clone syscall jumps to _exit after the child execution
and the function ends the process execution by calling exit_group.
This behavior have a small issue where threads created with
CLONE_THREAD using clone syscall directly will eventually exit the
whole group altogether instead of just the thread created.  Also,
s390, microblaze, ia64, i386, and m68k differs by calling exit
syscall directly.

This patch changes all architectures to call the exit syscall
directly, as for s390, microblaze, ia64, i386, and m68k.  This do not
have change glibc internal behavior in any sort, since the only
usage of clone implementation in posix_spawn calls _exit directly
in the created child (fork uses a direct call to clone).

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
powerpc-linux-gnu, powerpc64le-linux-gnu, sparc64-linux-gnu,
and sparcv9-linux-gnu.

	[BZ #21512]
	* sysdeps/unix/sysv/linux/aarch64/clone.S (__clone): Call exit
	syscall instead of jump to _exit.
	(CLONE_VM_BIT): Remove unused define.
	(CLONE_VM): Likewise.
	(CLONE_THREAD_BIT): Likewise.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/alpha/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/arm/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/i386/clone.S (CLONE_VM): Likewise.
	* sysdeps/unix/sysv/linux/ia64/clone2.S (__clone2): Call exit
	syscall instead of jump to _exit.
	* sysdeps/unix/sysv/linux/hppa/clone.S (__clone): Likewise.
	* sysdeps/unix/sysv/linux/mips/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/nios2/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S (__clone):
	Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S (__clone):
	Likewise.
	(CLONE_VM): Remove unused define.
	(CLONE_THREAD): Likewise.
	* sysdeps/unix/sysv/linux/sh/clone.S  (__clone): Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/tile/clone.S (__clone): Likewise.
	* sysdeps/unix/sysv/linux/x86_64/clone.S (__clone): Likewise.
	(CLONE_VM): Remove unused define.
	* sysdeps/unix/sysv/linux/Makefile (tests): Add tst-clone3.
	* sysdeps/unix/sysv/linux/tst-clone3.c: New file.

Fix
2017-06-26 17:52:20 -03:00

114 lines
2.8 KiB
ArmAsm

/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth@tamu.edu>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
/* clone() is even more special than fork() as it mucks with stacks
and invokes a function in the right context after its all over. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
/* int clone(int (*fn)(void *arg), void *child_stack, int flags,
void *arg, pid_t *ptid, void *tls, pid_t *ctid);
Note that everything past ARG is technically optional, based
on FLAGS, and that CTID is arg 7, and thus is on the stack.
However, since a load from top-of-stack better be legal always,
we don't bother checking FLAGS. */
.text
.align 4
.globl __clone
.ent __clone
.usepv __clone, USEPV_PROF
cfi_startproc
__clone:
#ifdef PROF
ldgp gp,0(pv)
lda AT, _mcount
jsr AT, (AT), _mcount
#endif
/* Sanity check arguments. */
ldiq v0, EINVAL
beq a0, SYSCALL_ERROR_LABEL /* no NULL function pointers */
beq a1, SYSCALL_ERROR_LABEL /* no NULL stack pointers */
/* Save the fn ptr and arg on the new stack. */
subq a1, 32, a1
stq a0, 0(a1)
stq a3, 8(a1)
stq a2, 16(a1)
/* The syscall is of the form clone(flags, usp, ptid, ctid, tls).
Shift the flags, ptid, ctid, tls arguments into place; the
child_stack argument is already correct. */
mov a2, a0
mov a4, a2
ldq a3, 0(sp)
mov a5, a4
/* Do the system call. */
ldiq v0, __NR_clone
call_pal PAL_callsys
bne a3, SYSCALL_ERROR_LABEL
beq v0, thread_start
/* Successful return from the parent. */
ret
PSEUDO_END(__clone)
cfi_endproc
/* Load up the arguments to the function. Put this block of code in
its own function so that we can terminate the stack trace with our
debug info. */
.align 4
.ent thread_start
cfi_startproc
thread_start:
mov 0, fp
cfi_def_cfa_register(fp)
cfi_undefined(ra)
/* Load up the arguments. */
ldq pv, 0(sp)
ldq a0, 8(sp)
addq sp, 32, sp
/* Call the user's function. */
jsr ra, (pv)
ldgp gp, 0(ra)
ldiq v0, __NR_exit
call_pal PAL_callsys
/* Die horribly. */
.align 4
halt
.align 4
cfi_endproc
.end thread_start
libc_hidden_def (__clone)
weak_alias (__clone, clone)