aboutsummaryrefslogtreecommitdiff
path: root/nptl/sysdeps/unix/sysv/linux
diff options
context:
space:
mode:
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux')
-rw-r--r--nptl/sysdeps/unix/sysv/linux/i386/vfork.S87
1 files changed, 87 insertions, 0 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/i386/vfork.S b/nptl/sysdeps/unix/sysv/linux/i386/vfork.S
new file mode 100644
index 0000000000..787453427b
--- /dev/null
+++ b/nptl/sysdeps/unix/sysv/linux/i386/vfork.S
@@ -0,0 +1,87 @@
+/* Copyright (C) 1999, 2002, 2004 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.h>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+#include <kernel-features.h>
+#include <tcb-offsets.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
+
+ /* Pop the return PC value into ECX. */
+ popl %ecx
+
+ /* Save the PID value. */
+ movl %gs:PID, %edx
+ movl $-1, %gs:PID
+
+ /* 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
+
+ /* Restore the old PID value in the parent. In the child store 0. */
+ testl %eax, %eax
+ je 1f
+ movl %edx, %gs:PID
+
+1: 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
+#endif
+PSEUDO_END (__vfork)
+libc_hidden_def (__vfork)
+
+weak_alias (__vfork, vfork)