projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| b168057a | 1 | /* Copyright (C) 2001-2015 Free Software Foundation, Inc. |
| c9cf6dde AJ |
2 | This file is part of the GNU C Library. |
| 3 | ||
| 4 | The GNU C Library is free software; you can redistribute it and/or | |
| 5 | modify it under the terms of the GNU Lesser General Public | |
| 6 | License as published by the Free Software Foundation; either | |
| 7 | version 2.1 of the License, or (at your option) any later version. | |
| 8 | ||
| 9 | The GNU C Library is distributed in the hope that it will be useful, | |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 12 | Lesser General Public License for more details. | |
| 13 | ||
| 14 | You should have received a copy of the GNU Lesser General Public | |
| 59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
| 16 | <http://www.gnu.org/licenses/>. */ | |
| c9cf6dde AJ |
17 | |
| 18 | #include <sysdep.h> | |
| 19 | #define _ERRNO_H 1 | |
| 20 | #include <bits/errno.h> | |
| e2787137 RM |
21 | #include <tcb-offsets.h> |
| 22 | ||
| c9cf6dde AJ |
23 | |
| 24 | /* Clone the calling process, but without copying the whole address space. | |
| 25 | The calling process is suspended until the new process exits or is | |
| 26 | replaced by a call to `execve'. Return -1 for errors, 0 to the new process, | |
| 27 | and the process ID of the new process to the old process. */ | |
| 28 | ||
| 29 | ENTRY (__vfork) | |
| 30 | ||
| 04d12383 AJ |
31 | /* Pop the return PC value into RDI. We need a register that |
| 32 | is preserved by the syscall and that we're allowed to destroy. */ | |
| acd42b78 | 33 | popq %rdi |
| 0e328c85 | 34 | cfi_adjust_cfa_offset(-8) |
| 6c30d38f | 35 | cfi_register(%rip, %rdi) |
| c9cf6dde | 36 | |
| e2787137 RM |
37 | /* Save the TCB-cached PID away in %esi, and then negate the TCB |
| 38 | field. But if it's zero, set it to 0x80000000 instead. See | |
| 39 | raise.c for the logic that relies on this value. */ | |
| 40 | movl %fs:PID, %esi | |
| 41 | movl $0x80000000, %ecx | |
| 42 | movl %esi, %edx | |
| 43 | negl %edx | |
| 44 | cmove %ecx, %edx | |
| 45 | movl %edx, %fs:PID | |
| 6fadea9f | 46 | |
| c9cf6dde AJ |
47 | /* Stuff the syscall number in RAX and enter into the kernel. */ |
| 48 | movl $SYS_ify (vfork), %eax | |
| 49 | syscall | |
| c9cf6dde | 50 | |
| c9cf6dde | 51 | /* Push back the return PC. */ |
| 04d12383 | 52 | pushq %rdi |
| 0e328c85 | 53 | cfi_adjust_cfa_offset(8) |
| c9cf6dde | 54 | |
| e2787137 RM |
55 | /* Restore the original value of the TCB cache of the PID, if we're |
| 56 | the parent. But in the child (syscall return value equals zero), | |
| 57 | leave things as they are. */ | |
| 58 | testq %rax, %rax | |
| 59 | je 1f | |
| 60 | movl %esi, %fs:PID | |
| 61 | 1: | |
| 6fadea9f | 62 | |
| acd42b78 UD |
63 | cmpl $-4095, %eax |
| 64 | jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */ | |
| 65 | ||
| 66 | /* Normal return. */ | |
| c9cf6dde AJ |
67 | ret |
| 68 | ||
| 69 | PSEUDO_END (__vfork) | |
| a4baf360 | 70 | libc_hidden_def (__vfork) |
| c9cf6dde AJ |
71 | |
| 72 | weak_alias (__vfork, vfork) | |
| e2787137 | 73 | strong_alias (__vfork, __libc_vfork) |