1 /* Copyright (C) 1999, 2002, 2004, 2005, 2008 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Andreas Schwab <schwab@gnu.org>.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
22 #include <bits/errno.h>
23 #include <kernel-features.h>
25 /* Clone the calling process, but without copying the whole address space.
26 The calling process is suspended until the new process exits or is
27 replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
28 and the process ID of the new process to the old process. */
34 /* Pop the return PC value into ECX. */
36 cfi_adjust_cfa_offset (-4)
37 cfi_register (%eip, %ecx)
43 /* Stuff the syscall number in EAX and enter into the kernel. */
44 movl $SYS_ify (vfork), %eax
47 /* Jump to the return PC. Don't jump directly since this
48 disturbs the branch target cache. Instead push the return
49 address back on the stack. */
51 cfi_adjust_cfa_offset (4)
58 /* Branch forward if it failed. */
59 # ifdef __ASSUME_VFORK_SYSCALL
60 jae SYSCALL_ERROR_LABEL
68 # ifndef __ASSUME_VFORK_SYSCALL
70 /* Check if vfork syscall is known at all. */
72 jne SYSCALL_ERROR_LABEL
76 #ifndef __ASSUME_VFORK_SYSCALL
77 /* If we don't have vfork, fork is close enough. */
79 movl $SYS_ify (fork), %eax
82 jae SYSCALL_ERROR_LABEL
87 libc_hidden_def (__vfork)
89 weak_alias (__vfork, vfork)