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author | Ulrich Drepper <drepper@redhat.com> | 2004-03-09 05:45:44 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 2004-03-09 05:45:44 +0000 |
commit | c072ef6d229b1c504e0cff58371df892ec289dec (patch) | |
tree | a00f967b2dc67a51684be7b6c33b9fe821ca12bb /nptl/sysdeps | |
parent | 02287d05a00c8bac1c20545cb0bad43725b5045c (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')
-rw-r--r-- | nptl/sysdeps/unix/sysv/linux/i386/vfork.S | 87 |
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) |