diff options
Diffstat (limited to 'linuxthreads/sysdeps/unix/sysv/linux/i386/vfork.S')
-rw-r--r-- | linuxthreads/sysdeps/unix/sysv/linux/i386/vfork.S | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/linuxthreads/sysdeps/unix/sysv/linux/i386/vfork.S b/linuxthreads/sysdeps/unix/sysv/linux/i386/vfork.S new file mode 100644 index 0000000000..c7a120d239 --- /dev/null +++ b/linuxthreads/sysdeps/unix/sysv/linux/i386/vfork.S @@ -0,0 +1,95 @@ +/* Copyright (C) 1999, 2002, 2003 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Andreas Schwab <schwab@gnu.org>. + + 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <sysdep-cancel.h> +#define _ERRNO_H 1 +#include <bits/errno.h> +#include <kernel-features.h> + +/* Clone the calling process, but without copying the whole address space. + The calling process is suspended until the new process exits or is + replaced by a call to `execve'. Return -1 for errors, 0 to the new process, + and the process ID of the new process to the old process. */ + +ENTRY (__vfork) + +#ifdef __NR_vfork + +# ifdef SHARED +# if !defined HAVE_HIDDEN || !USE___THREAD + SETUP_PIC_REG (cx) +# else + call __i686.get_pc_thunk.cx +# endif + addl $_GLOBAL_OFFSET_TABLE_, %ecx + cmpl $0, __libc_pthread_functions@GOTOFF(%ecx) +# else + .weak pthread_create + movl $pthread_create, %eax + testl %eax, %eax +# endif + jne HIDDEN_JUMPTARGET (__fork) + + /* Pop the return PC value into ECX. */ + popl %ecx + + /* Stuff the syscall number in EAX and enter into the kernel. */ + movl $SYS_ify (vfork), %eax + int $0x80 + + /* Jump to the return PC. Don't jump directly since this + disturbs the branch target cache. Instead push the return + address back on the stack. */ + pushl %ecx + + cmpl $-4095, %eax + /* Branch forward if it failed. */ +# ifdef __ASSUME_VFORK_SYSCALL + jae SYSCALL_ERROR_LABEL +.Lpseudo_end: +# else + jae .Lerror +# endif + + ret + +# ifndef __ASSUME_VFORK_SYSCALL +.Lerror: + /* Check if vfork syscall is known at all. */ + cmpl $-ENOSYS, %eax + jne SYSCALL_ERROR_LABEL +# endif +#endif + +#ifndef __ASSUME_VFORK_SYSCALL + /* If we don't have vfork, fork is close enough. */ + + movl $SYS_ify (fork), %eax + int $0x80 + cmpl $-4095, %eax + jae SYSCALL_ERROR_LABEL +.Lpseudo_end: + ret +#elif !defined __NR_vfork +# error "__NR_vfork not available and __ASSUME_VFORK_SYSCALL defined" +#endif +PSEUDO_END (__vfork) +libc_hidden_def (__vfork) + +weak_alias (__vfork, vfork) |