1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2018 Mark Johnston <markj@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 #include <sys/types.h> 30 #include <sys/syscall.h> 31 #include <errno.h> 32 #include <stdint.h> 33 #include <stdlib.h> 34 35 void *__sys_break(char *nsize); 36 37 static uintptr_t curbrk, minbrk; 38 static int curbrk_initted; 39 40 static int 41 initbrk(void) 42 { 43 void *newbrk; 44 45 if (!curbrk_initted) { 46 newbrk = __sys_break(NULL); 47 if (newbrk == (void *)-1) 48 return (-1); 49 curbrk = minbrk = (uintptr_t)newbrk; 50 curbrk_initted = 1; 51 } 52 return (0); 53 } 54 55 static void * 56 mvbrk(void *addr) 57 { 58 uintptr_t oldbrk; 59 60 if ((uintptr_t)addr < minbrk) { 61 /* Emulate legacy error handling in the syscall. */ 62 errno = EINVAL; 63 return ((void *)-1); 64 } 65 if (__sys_break(addr) == (void *)-1) 66 return ((void *)-1); 67 oldbrk = curbrk; 68 curbrk = (uintptr_t)addr; 69 return ((void *)oldbrk); 70 } 71 72 int 73 brk(const void *addr) 74 { 75 76 if (initbrk() == -1) 77 return (-1); 78 if ((uintptr_t)addr < minbrk) 79 addr = (void *)minbrk; 80 return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0); 81 } 82 83 int 84 _brk(const void *addr) 85 { 86 87 if (initbrk() == -1) 88 return (-1); 89 return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0); 90 } 91 92 void * 93 sbrk(intptr_t incr) 94 { 95 96 if (initbrk() == -1) 97 return ((void *)-1); 98 if ((incr > 0 && curbrk + incr < curbrk) || 99 (incr < 0 && curbrk + incr > curbrk)) { 100 /* Emulate legacy error handling in the syscall. */ 101 errno = EINVAL; 102 return ((void *)-1); 103 } 104 return (mvbrk((void *)(curbrk + incr))); 105 } 106