1 /* $OpenBSD: alloc.c,v 1.9 2015/10/16 03:17:56 mmcc Exp $ */ 2 /* 3 * Copyright (c) 2002 Marc Espie. 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 * 14 * THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS 15 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD 18 * PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 /* 28 * area-based allocation built on malloc/free 29 */ 30 31 #include <stdint.h> 32 #include "sh.h" 33 34 struct link { 35 struct link *prev; 36 struct link *next; 37 }; 38 39 Area * 40 ainit(Area *ap) 41 { 42 ap->freelist = NULL; 43 return ap; 44 } 45 46 void 47 afreeall(Area *ap) 48 { 49 struct link *l, *l2; 50 51 for (l = ap->freelist; l != NULL; l = l2) { 52 l2 = l->next; 53 free(l); 54 } 55 ap->freelist = NULL; 56 } 57 58 #define L2P(l) ( (void *)(((char *)(l)) + sizeof(struct link)) ) 59 #define P2L(p) ( (struct link *)(((char *)(p)) - sizeof(struct link)) ) 60 61 void * 62 alloc(size_t size, Area *ap) 63 { 64 struct link *l; 65 66 l = malloc(sizeof(struct link) + size); 67 if (l == NULL) 68 internal_errorf(1, "unable to allocate memory"); 69 l->next = ap->freelist; 70 l->prev = NULL; 71 if (ap->freelist) 72 ap->freelist->prev = l; 73 ap->freelist = l; 74 75 return L2P(l); 76 } 77 78 /* 79 * Copied from calloc(). 80 * 81 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX 82 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW 83 */ 84 #define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 4)) 85 86 void * 87 allocarray(size_t nmemb, size_t size, Area *ap) 88 { 89 /* condition logic cloned from calloc() */ 90 if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && 91 nmemb > 0 && SIZE_MAX / nmemb < size) { 92 internal_errorf(1, "unable to allocate memory"); 93 } 94 95 /* additional check because alloc() allocates space for link */ 96 if (nmemb * size > SIZE_MAX - sizeof(struct link)) 97 internal_errorf(1, "unable to allocate memory"); 98 99 return alloc(nmemb * size, ap); 100 } 101 102 void * 103 aresize(void *ptr, size_t size, Area *ap) 104 { 105 struct link *l, *l2, *lprev, *lnext; 106 107 if (ptr == NULL) 108 return alloc(size, ap); 109 110 l = P2L(ptr); 111 lprev = l->prev; 112 lnext = l->next; 113 114 l2 = realloc(l, sizeof(struct link) + size); 115 if (l2 == NULL) 116 internal_errorf(1, "unable to allocate memory"); 117 if (lprev) 118 lprev->next = l2; 119 else 120 ap->freelist = l2; 121 if (lnext) 122 lnext->prev = l2; 123 124 return L2P(l2); 125 } 126 127 void 128 afree(void *ptr, Area *ap) 129 { 130 struct link *l, *l2; 131 132 if (!ptr) 133 return; 134 135 l = P2L(ptr); 136 137 for (l2 = ap->freelist; l2 != NULL; l2 = l2->next) { 138 if (l == l2) 139 break; 140 } 141 if (l2 == NULL) 142 internal_errorf(1, "afree: %p not present in area %p", ptr, ap); 143 144 if (l->prev) 145 l->prev->next = l->next; 146 else 147 ap->freelist = l->next; 148 if (l->next) 149 l->next->prev = l->prev; 150 151 free(l); 152 } 153