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