1 /* Copyright (C) 1999, 2002, 2003 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, see
17 <http://www.gnu.org/licenses/>. */
19 #include <sysdep-cancel.h>
21 #include <bits/errno.h>
22 #include <bits/kernel-features.h>
24 /* Clone the calling process, but without copying the whole address space.
25 The calling process is suspended until the new process exits or is
26 replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
27 and the process ID of the new process to the old process. */
34 # if !defined HAVE_HIDDEN || !defined __UCLIBC_HAS_TLS__
37 call __i686.get_pc_thunk.cx
39 addl $_GLOBAL_OFFSET_TABLE_, %ecx
40 cmpl $0, __libc_pthread_functions@GOTOFF(%ecx)
43 movl $pthread_create, %eax
46 jne HIDDEN_JUMPTARGET (fork)
48 /* Pop the return PC value into ECX. */
51 /* Stuff the syscall number in EAX and enter into the kernel. */
52 movl $SYS_ify (vfork), %eax
55 /* Jump to the return PC. Don't jump directly since this
56 disturbs the branch target cache. Instead push the return
57 address back on the stack. */
61 /* Branch forward if it failed. */
62 # ifdef __ASSUME_VFORK_SYSCALL
63 jae SYSCALL_ERROR_LABEL
71 # ifndef __ASSUME_VFORK_SYSCALL
73 /* Check if vfork syscall is known at all. */
75 jne SYSCALL_ERROR_LABEL
79 #ifndef __ASSUME_VFORK_SYSCALL
80 /* If we don't have vfork, fork is close enough. */
82 movl $SYS_ify (fork), %eax
85 jae SYSCALL_ERROR_LABEL
88 #elif !defined __NR_vfork
89 # error "__NR_vfork not available and __ASSUME_VFORK_SYSCALL defined"
92 libc_hidden_def (__vfork)
94 weak_alias (__vfork, vfork)