diff options
Diffstat (limited to 'libc/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S')
-rw-r--r-- | libc/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/libc/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S b/libc/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S new file mode 100644 index 000000000..24f5a1d29 --- /dev/null +++ b/libc/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S @@ -0,0 +1,68 @@ +/* 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> + +/* Save the PID value. */ +#define SAVE_PID \ + movl %gs:PID, %edx; \ + movl %edx, %eax; \ + negl %eax; \ + movl %eax, %gs:PID + +/* Restore the old PID value in the parent. */ +#define RESTORE_PID \ + testl %eax, %eax; \ + je 1f; \ + movl %edx, %gs:PID; \ +1: + +/* 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) + /* Pop the return PC value into ECX. */ + popl %ecx + + SAVE_PID + + /* Stuff the syscall number in EAX and enter into the kernel. */ + movl $SYS_ify (vfork), %eax + int $0x80 + + RESTORE_PID + + /* 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 + jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */ +.Lpseudo_end: + ret +PSEUDO_END (__vfork) + +weak_alias (__vfork, vfork) |