1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 __FBSDID("$FreeBSD$"); 30 31 #include <sys/types.h> 32 #include <sys/syscall.h> 33 #include <errno.h> 34 #include <stdint.h> 35 #include <stdlib.h> 36 37 void *__sys_break(char *nsize); 38 39 static uintptr_t curbrk, minbrk; 40 static int curbrk_initted; 41 42 static int 43 initbrk(void) 44 { 45 void *newbrk; 46 47 if (!curbrk_initted) { 48 newbrk = __sys_break(NULL); 49 if (newbrk == (void *)-1) 50 return (-1); 51 curbrk = minbrk = (uintptr_t)newbrk; 52 curbrk_initted = 1; 53 } 54 return (0); 55 } 56 57 static void * 58 mvbrk(void *addr) 59 { 60 uintptr_t oldbrk; 61 62 if ((uintptr_t)addr < minbrk) { 63 /* Emulate legacy error handling in the syscall. */ 64 errno = EINVAL; 65 return ((void *)-1); 66 } 67 if (__sys_break(addr) == (void *)-1) 68 return ((void *)-1); 69 oldbrk = curbrk; 70 curbrk = (uintptr_t)addr; 71 return ((void *)oldbrk); 72 } 73 74 int 75 brk(const void *addr) 76 { 77 78 if (initbrk() == -1) 79 return (-1); 80 if ((uintptr_t)addr < minbrk) 81 addr = (void *)minbrk; 82 return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0); 83 } 84 85 int 86 _brk(const void *addr) 87 { 88 89 if (initbrk() == -1) 90 return (-1); 91 return (mvbrk(__DECONST(void *, addr)) == (void *)-1 ? -1 : 0); 92 } 93 94 void * 95 sbrk(intptr_t incr) 96 { 97 98 if (initbrk() == -1) 99 return ((void *)-1); 100 if ((incr > 0 && curbrk + incr < curbrk) || 101 (incr < 0 && curbrk + incr > curbrk)) { 102 /* Emulate legacy error handling in the syscall. */ 103 errno = EINVAL; 104 return ((void *)-1); 105 } 106 return (mvbrk((void *)(curbrk + incr))); 107 } 108