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 "includes.h" 21 #ifndef HAVE_RECALLOCARRAY 22 23 #include <errno.h> 24 #include <stdlib.h> 25 #ifdef HAVE_STDINT_H 26 #include <stdint.h> 27 #endif 28 #include <string.h> 29 #include <unistd.h> 30 31 /* 32 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX 33 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW 34 */ 35 #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4)) 36 37 void * 38 recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size) 39 { 40 size_t oldsize, newsize; 41 void *newptr; 42 43 if (ptr == NULL) 44 return calloc(newnmemb, size); 45 46 if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && 47 newnmemb > 0 && SIZE_MAX / newnmemb < size) { 48 errno = ENOMEM; 49 return NULL; 50 } 51 newsize = newnmemb * size; 52 53 if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && 54 oldnmemb > 0 && SIZE_MAX / oldnmemb < size) { 55 errno = EINVAL; 56 return NULL; 57 } 58 oldsize = oldnmemb * size; 59 60 /* 61 * Don't bother too much if we're shrinking just a bit, 62 * we do not shrink for series of small steps, oh well. 63 */ 64 if (newsize <= oldsize) { 65 size_t d = oldsize - newsize; 66 67 if (d < oldsize / 2 && d < (size_t)getpagesize()) { 68 memset((char *)ptr + newsize, 0, d); 69 return ptr; 70 } 71 } 72 73 newptr = malloc(newsize); 74 if (newptr == NULL) 75 return NULL; 76 77 if (newsize > oldsize) { 78 memcpy(newptr, ptr, oldsize); 79 memset((char *)newptr + oldsize, 0, newsize - oldsize); 80 } else 81 memcpy(newptr, ptr, newsize); 82 83 explicit_bzero(ptr, oldsize); 84 free(ptr); 85 86 return newptr; 87 } 88 /* DEF_WEAK(recallocarray); */ 89 90 #endif /* HAVE_RECALLOCARRAY */ 91