1 /* 2 * Copyright (c) 2019 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 /* 35 * As of 500503 the sbrk() system call works. Prior to 500503 the sbrk() 36 * system call returns EOPNOTSUPP and must be emulated by libc, which we 37 * accomplish with some fake_sbrk() assembly that calls into the even older 38 * 'break' system call. 39 * 40 * Note that in older kernels sbrk() does not ENOSYS or generate a signal. 41 * It returns -1 and EOPNOTSUPP. 42 * 43 * libc generates the normal sbrk() system call where 'sbrk' is a weak 44 * symbol. We override it here. 45 */ 46 #include "namespace.h" 47 #include <sys/errno.h> 48 #include <time.h> 49 #include <unistd.h> 50 #include "un-namespace.h" 51 52 void *_sbrk(intptr_t incr); 53 void *fake_sbrk(intptr_t incr); 54 55 void * 56 sbrk(intptr_t incr) 57 { 58 void *res; 59 60 res = _sbrk(incr); 61 if (res == (void *)-1 && errno == EOPNOTSUPP) 62 res = fake_sbrk(incr); 63 return res; 64 } 65