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
29int
30vasprintf(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