1 /* $OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $ */ 2 /* 3 * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 /* OPENBSD ORIGINAL: lib/libc/stdlib/recallocarray.c */ 19 20 #include "openbsd-compat.h" 21 22 #if !defined(HAVE_RECALLOCARRAY) 23 24 #include <errno.h> 25 #include <stdlib.h> 26 #include <stdint.h> 27 #include <string.h> 28 #ifdef HAVE_UNISTD_H 29 #include <unistd.h> 30 #endif 31 32 /* 33 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX 34 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW 35 */ 36 #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4)) 37 38 void * 39 recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size) 40 { 41 size_t oldsize, newsize; 42 void *newptr; 43 44 if (ptr == NULL) 45 return calloc(newnmemb, size); 46 47 if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && 48 newnmemb > 0 && SIZE_MAX / newnmemb < size) { 49 errno = ENOMEM; 50 return NULL; 51 } 52 newsize = newnmemb * size; 53 54 if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && 55 oldnmemb > 0 && SIZE_MAX / oldnmemb < size) { 56 errno = EINVAL; 57 return NULL; 58 } 59 oldsize = oldnmemb * size; 60 61 /* 62 * Don't bother too much if we're shrinking just a bit, 63 * we do not shrink for series of small steps, oh well. 64 */ 65 if (newsize <= oldsize) { 66 size_t d = oldsize - newsize; 67 68 if (d < oldsize / 2 && d < (size_t)getpagesize()) { 69 memset((char *)ptr + newsize, 0, d); 70 return ptr; 71 } 72 } 73 74 newptr = malloc(newsize); 75 if (newptr == NULL) 76 return NULL; 77 78 if (newsize > oldsize) { 79 memcpy(newptr, ptr, oldsize); 80 memset((char *)newptr + oldsize, 0, newsize - oldsize); 81 } else 82 memcpy(newptr, ptr, newsize); 83 84 explicit_bzero(ptr, oldsize); 85 free(ptr); 86 87 return newptr; 88 } 89 /* DEF_WEAK(recallocarray); */ 90 91 #endif /* !defined(HAVE_RECALLOCARRAY) */ 92