1 /* $Id: compat_vasprintf.c,v 1.4 2020/06/15 01:37:15 schwarze Exp $ */ 2 /* 3 * Copyright (c) 2015 Ingo Schwarze <schwarze@openbsd.org> 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 * This fallback implementation is not efficient: 18 * It does the formatting twice. 19 * Short of fiddling with the unknown internals of the system's 20 * printf(3) or completely reimplementing printf(3), i can't think 21 * of another portable solution. 22 */ 23 #include "config.h" 24 25 #include <stdarg.h> 26 #include <stdio.h> 27 #include <stdlib.h> 28 29 int 30 vasprintf(char **ret, const char *format, va_list ap) 31 { 32 char buf[2]; 33 va_list ap2; 34 int sz; 35 36 va_copy(ap2, ap); 37 sz = vsnprintf(buf, sizeof(buf), format, ap2); 38 va_end(ap2); 39 40 if (sz != -1 && (*ret = malloc(sz + 1)) != NULL) { 41 if (vsnprintf(*ret, sz + 1, format, ap) == sz) 42 return sz; 43 free(*ret); 44 } 45 *ret = NULL; 46 return -1; 47 } 48