projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 842a39cd | 1 | /* Copyright (C) 1999-2012 Free Software Foundation, Inc. |
| 76a50749 UD |
2 | This file is part of the GNU C Library. |
| 3 | Contributed by Andreas Schwab <schwab@gnu.org>. | |
| 4 | ||
| 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. | |
| 9 | ||
| 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. | |
| 14 | ||
| 15 | You should have received a copy of the GNU Lesser General Public | |
| 59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ | |
| 76a50749 UD |
18 | |
| 19 | #include <sysdep.h> | |
| 20 | #define _ERRNO_H 1 | |
| 21 | #include <bits/errno.h> | |
| 22 | #include <kernel-features.h> | |
| 8b9d6054 UD |
23 | #include <tcb-offsets.h> |
| 24 | ||
| 25 | /* Save the PID value. */ | |
| 26 | #define SAVE_PID \ | |
| 27 | movl %gs:PID, %edx; \ | |
| 28 | movl %edx, %eax; \ | |
| 29 | negl %eax; \ | |
| 30 | movl %eax, %gs:PID | |
| 31 | ||
| 32 | /* Restore the old PID value in the parent. */ | |
| 33 | #define RESTORE_PID \ | |
| 34 | testl %eax, %eax; \ | |
| 35 | je 1f; \ | |
| 36 | movl %edx, %gs:PID; \ | |
| 37 | 1: | |
| 76a50749 UD |
38 | |
| 39 | /* Clone the calling process, but without copying the whole address space. | |
| 40 | The calling process is suspended until the new process exits or is | |
| 41 | replaced by a call to `execve'. Return -1 for errors, 0 to the new process, | |
| 42 | and the process ID of the new process to the old process. */ | |
| 43 | ||
| 44 | ENTRY (__vfork) | |
| 45 | /* Pop the return PC value into ECX. */ | |
| 46 | popl %ecx | |
| 47 | ||
| 8b9d6054 UD |
48 | SAVE_PID |
| 49 | ||
| 76a50749 UD |
50 | /* Stuff the syscall number in EAX and enter into the kernel. */ |
| 51 | movl $SYS_ify (vfork), %eax | |
| 52 | int $0x80 | |
| 53 | ||
| 8b9d6054 UD |
54 | RESTORE_PID |
| 55 | ||
| 76a50749 UD |
56 | /* Jump to the return PC. Don't jump directly since this |
| 57 | disturbs the branch target cache. Instead push the return | |
| 58 | address back on the stack. */ | |
| 59 | pushl %ecx | |
| 60 | ||
| 61 | cmpl $-4095, %eax | |
| 62 | jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */ | |
| 76a50749 UD |
63 | ret |
| 64 | PSEUDO_END (__vfork) | |
| 65 | ||
| 66 | weak_alias (__vfork, vfork) |