1/* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30#include "SYS.h" 31 32#if defined(SYSLIBC_SCCS) && !defined(lint) 33 /* .asciz "@(#)Ovfork.s 8.1 (Berkeley) 6/4/93" */ 34RCSID("$NetBSD: compat_Ovfork.S,v 1.2 2011/01/25 02:38:16 matt Exp $") 35#endif /* SYSLIBC_SCCS and not lint */ 36 37/* 38 * @(#)vfork.s 4.1 (Berkeley) 12/21/80 39 * C library -- vfork 40 */ 41 42WARN_REFERENCES(vfork, \ 43 "warning: reference to compatibility vfork(); include <unistd.h> for correct reference") 44 45/* 46 * pid = vfork(); 47 * 48 * %r1 == 0 in parent process, %r1 == 1 in child process. 49 * %r0 == pid of child in parent, %r0 == pid of parent in child. 50 * 51 * trickery here, due to keith sklower, uses ret to clear the stack, 52 * and then returns with a jump indirect, since only one person can return 53 * with a ret off this stack... we do the ret before we vfork! 54 */ 55 56ENTRY(vfork, 0) 57 movl 16(%fp),%r2 # save return address before we smash it 58 movab here,16(%fp) 59 ret 60here: 61 chmk $ SYS_vfork 62 bcs err # if failed, set errno and return -1 63 /* this next trick is Chris Torek's fault */ 64 mnegl %r1,%r1 # %r1 = 0xffffffff if child, 0 if parent 65 bicl2 %r1,%r0 # %r0 &= ~%r1, i.e., 0 if child, else unchanged 66 jmp (%r2) 67 68err: 69#ifdef _REENTRANT 70 pushr $0x5 71 calls $0,_C_LABEL(__errno) 72 movl (%sp)+,(%r0) 73 mnegl $1,%r0 74 rsb 75#else 76 movl %r0,_C_LABEL(errno) 77 mnegl $1,%r0 78 jmp (%r2) 79#endif 80END(vfork) 81