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 #include <errno.h> 19 #include <stdckdint.h> 20 #include <stdlib.h> 21 #include <stdint.h> 22 #include <string.h> 23 #include <unistd.h> 24 25 void *recallocarray(void *, size_t, size_t, size_t); 26 27 void * 28 recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size) 29 { 30 size_t oldsize, newsize; 31 void *newptr; 32 33 if (ptr == NULL) 34 return calloc(newnmemb, size); 35 36 if (ckd_mul(&newsize, newnmemb, size)) { 37 errno = ENOMEM; 38 return NULL; 39 } 40 41 if (ckd_mul(&oldsize, oldnmemb, size)) { 42 errno = EINVAL; 43 return NULL; 44 } 45 46 /* 47 * Don't bother too much if we're shrinking just a bit, 48 * we do not shrink for series of small steps, oh well. 49 */ 50 if (newsize <= oldsize) { 51 size_t d = oldsize - newsize; 52 53 if (d < oldsize / 2 && d < (size_t)getpagesize()) { 54 memset((char *)ptr + newsize, 0, d); 55 return ptr; 56 } 57 } 58 59 newptr = malloc(newsize); 60 if (newptr == NULL) 61 return NULL; 62 63 if (newsize > oldsize) { 64 memcpy(newptr, ptr, oldsize); 65 memset((char *)newptr + oldsize, 0, newsize - oldsize); 66 } else 67 memcpy(newptr, ptr, newsize); 68 69 explicit_bzero(ptr, oldsize); 70 free(ptr); 71 72 return newptr; 73 } 74