projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| a4fc57ac | 1 | /*- |
| 7217fa4b KB |
2 | * Copyright (c) 1983, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. | |
| ffed8673 | 4 | * |
| c0567266 KB |
5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions | |
| 7 | * are met: | |
| 8 | * 1. Redistributions of source code must retain the above copyright | |
| 9 | * notice, this list of conditions and the following disclaimer. | |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright | |
| 11 | * notice, this list of conditions and the following disclaimer in the | |
| 12 | * documentation and/or other materials provided with the distribution. | |
| 13 | * 3. All advertising materials mentioning features or use of this software | |
| 14 | * must display the following acknowledgement: | |
| 15 | * This product includes software developed by the University of | |
| 16 | * California, Berkeley and its contributors. | |
| 17 | * 4. Neither the name of the University nor the names of its contributors | |
| 18 | * may be used to endorse or promote products derived from this software | |
| 19 | * without specific prior written permission. | |
| 20 | * | |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 31 | * SUCH DAMAGE. | |
| ffed8673 KB |
32 | */ |
| 33 | ||
| 34 | #if defined(LIBC_SCCS) && !defined(lint) | |
| ad787160 | 35 | .asciz "@(#)Ovfork.c 8.1 (Berkeley) 6/4/93" |
| ffed8673 KB |
36 | #endif /* LIBC_SCCS and not lint */ |
| 37 | ||
| 38 | /* | |
| 39 | * @(#)vfork.s 4.1 (Berkeley) 12/21/80 | |
| 40 | * C library -- vfork | |
| 41 | */ | |
| 42 | ||
| 43 | /* | |
| 44 | * pid = vfork(); | |
| 45 | * | |
| 46 | * r1 == 0 in parent process, r1 == 1 in child process. | |
| 47 | * r0 == pid of child in parent, r0 == pid of parent in child. | |
| 48 | * | |
| 49 | * trickery here, due to keith sklower, uses ret to clear the stack, | |
| 50 | * and then returns with a jump indirect, since only one person can return | |
| 51 | * with a ret off this stack... we do the ret before we vfork! | |
| 52 | */ | |
| 53 | ||
| 54 | .set vfork,66 | |
| 55 | .globl _vfork | |
| 56 | .globl mypid, myppid | |
| 57 | ||
| 58 | _vfork: | |
| 59 | .word 0x0000 | |
| 60 | movl 16(fp),r2 | |
| 61 | movab here,16(fp) | |
| 62 | ret | |
| 63 | here: | |
| 64 | chmk $vfork | |
| 65 | bcc vforkok | |
| 66 | jmp verror | |
| 67 | vforkok: | |
| 68 | tstl r1 # child process ? | |
| 69 | bneq child # yes | |
| 70 | bcc parent # if c-bit not set, fork ok | |
| 71 | .globl _errno | |
| 72 | verror: | |
| 73 | movl r0,_errno | |
| 74 | mnegl $1,r0 | |
| 75 | jmp (r2) | |
| 76 | child: | |
| 77 | movl r0,myppid | |
| 78 | clrl r0 | |
| 79 | clrl mypid | |
| 80 | parent: | |
| 81 | jmp (r2) |