xref: /src/lib/libc/stdio/vasprintf.c

/*	$NetBSD: vasprintf.c,v 1.13.2.1 2012/04/17 00:05:25 yamt Exp $	*/

/*
 * Copyright (c) 1997 Todd C. Miller <Todd.Miller (at) courtesan.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: vasprintf.c,v 1.13.2.1 2012/04/17 00:05:25 yamt Exp $");
#endif /* LIBC_SCCS and not lint */

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include "reentrant.h"
#include "local.h"

int
vasprintf(char **str, const char *fmt, va_list ap)
{
	int ret;
	FILE f;
	struct __sfileext fext;
	unsigned char *_base;

	_DIAGASSERT(str != NULL);
	_DIAGASSERT(fmt != NULL);

	_FILEEXT_SETUP(&f, &fext);
	f._file = -1;
	f._flags = __SWR | __SSTR | __SALC;
	f._bf._base = f._p = (unsigned char *)malloc(128);
	if (f._bf._base == NULL)
		goto err;
	f._bf._size = f._w = 127;		/* Leave room for the NUL */
	ret = __vfprintf_unlocked(&f, fmt, ap);
	if (ret == -1)
		goto err;
	*f._p = '\0';
	_base = realloc(f._bf._base, (size_t)(ret + 1));
	if (_base == NULL)
		goto err;
	*str = (char *)_base;
	return ret;

err:
	if (f._bf._base)
		free(f._bf._base);
	*str = NULL;
	errno = ENOMEM;
	return -1;
}