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authorUlrich Drepper <drepper@redhat.com>2004-03-09 05:45:44 +0000
committerUlrich Drepper <drepper@redhat.com>2004-03-09 05:45:44 +0000
commitc072ef6d229b1c504e0cff58371df892ec289dec (patch)
treea00f967b2dc67a51684be7b6c33b9fe821ca12bb /nptl/sysdeps/unix/sysv/linux/i386/vfork.S
parent02287d05a00c8bac1c20545cb0bad43725b5045c (diff)
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Update.
	* sysdeps/i386/tcb-offsets.sym: Add PID.
	* sysdeps/unix/sysv/linux/i386/vfork.S: New file.
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/i386/vfork.S')
-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)