1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #pragma weak sbrk = _sbrk 30 #pragma weak brk = _brk 31 32 #include "synonyms.h" 33 #include <synch.h> 34 #include <errno.h> 35 #include <sys/isa_defs.h> 36 #include <sys/types.h> 37 #include <sys/sysmacros.h> 38 #include <inttypes.h> 39 #include <unistd.h> 40 #include "mtlib.h" 41 #include "libc.h" 42 43 extern int _end; 44 void *_nd = &_end; 45 mutex_t __sbrk_lock = DEFAULTMUTEX; 46 47 extern int _brk_unlocked(void *); 48 void *_sbrk_unlocked(intptr_t); 49 50 /* 51 * The break must always be at least 8-byte aligned 52 */ 53 #if (_MAX_ALIGNMENT < 8) 54 #define ALIGNSZ 8 55 #else 56 #define ALIGNSZ _MAX_ALIGNMENT 57 #endif 58 59 #define BRKALIGN(x) (caddr_t)P2ROUNDUP((uintptr_t)(x), ALIGNSZ) 60 61 void * 62 sbrk(intptr_t addend) 63 { 64 void *result; 65 66 lmutex_lock(&__sbrk_lock); 67 result = _sbrk_unlocked(addend); 68 lmutex_unlock(&__sbrk_lock); 69 70 return (result); 71 } 72 73 /* 74 * _sbrk_unlocked() aligns the old break, adds the addend, aligns 75 * the new break, and calls _brk_unlocked() to set the new break. 76 * We must align the old break because _nd may begin life misaligned. 77 * The addend can be either positive or negative, so there are two 78 * overflow/underflow edge conditions to reject: 79 * 80 * - the addend is negative and brk + addend < 0. 81 * - the addend is positive and brk + addend > ULONG_MAX 82 */ 83 void * 84 _sbrk_unlocked(intptr_t addend) 85 { 86 char *old_brk = BRKALIGN(_nd); 87 char *new_brk = BRKALIGN(old_brk + addend); 88 89 if (!primary_link_map) { 90 errno = ENOTSUP; 91 return ((void *)-1); 92 } 93 if ((addend > 0 && new_brk < old_brk) || 94 (addend < 0 && new_brk > old_brk)) { 95 errno = ENOMEM; 96 return ((void *)-1); 97 } 98 if (_brk_unlocked(new_brk) != 0) 99 return ((void *)-1); 100 _nd = new_brk; 101 return (old_brk); 102 } 103 104 /* 105 * _sbrk_grow_aligned() aligns the old break to a low_align boundry, 106 * adds min_size, aligns to a high_align boundry, and calls _brk_unlocked() 107 * to set the new break. The low_aligned-aligned value is returned, and 108 * the actual space allocated is returned through actual_size. 109 * 110 * Unlike sbrk(2), _sbrk_grow_aligned takes an unsigned size, and does 111 * not allow shrinking the heap. 112 */ 113 void * 114 _sbrk_grow_aligned(size_t min_size, size_t low_align, size_t high_align, 115 size_t *actual_size) 116 { 117 uintptr_t old_brk; 118 uintptr_t ret_brk; 119 uintptr_t high_brk; 120 uintptr_t new_brk; 121 int brk_result; 122 123 if (!primary_link_map) { 124 errno = ENOTSUP; 125 return ((void *)-1); 126 } 127 if ((low_align & (low_align - 1)) != 0 || 128 (high_align & (high_align - 1)) != 0) { 129 errno = EINVAL; 130 return ((void *)-1); 131 } 132 low_align = MAX(low_align, ALIGNSZ); 133 high_align = MAX(high_align, ALIGNSZ); 134 135 lmutex_lock(&__sbrk_lock); 136 137 old_brk = (uintptr_t)BRKALIGN(_nd); 138 ret_brk = P2ROUNDUP(old_brk, low_align); 139 high_brk = ret_brk + min_size; 140 new_brk = P2ROUNDUP(high_brk, high_align); 141 142 /* 143 * Check for overflow 144 */ 145 if (ret_brk < old_brk || high_brk < ret_brk || new_brk < high_brk) { 146 lmutex_unlock(&__sbrk_lock); 147 errno = ENOMEM; 148 return ((void *)-1); 149 } 150 151 if ((brk_result = _brk_unlocked((void *)new_brk)) == 0) 152 _nd = (void *)new_brk; 153 lmutex_unlock(&__sbrk_lock); 154 155 if (brk_result != 0) 156 return ((void *)-1); 157 158 if (actual_size != NULL) 159 *actual_size = (new_brk - ret_brk); 160 return ((void *)ret_brk); 161 } 162 163 int 164 brk(void *new_brk) 165 { 166 int result; 167 168 if (!primary_link_map) { 169 errno = ENOTSUP; 170 return (-1); 171 } 172 /* 173 * Need to align this here; _brk_unlocked won't do it for us. 174 */ 175 new_brk = BRKALIGN(new_brk); 176 177 lmutex_lock(&__sbrk_lock); 178 if ((result = _brk_unlocked(new_brk)) == 0) 179 _nd = new_brk; 180 lmutex_unlock(&__sbrk_lock); 181 182 return (result); 183 } 184