xref: /netbsd-src/lib/libc/stdio/vasprintf.c (revision a536ee5124e62c9a0051a252f7833dc8f50f44c9)
1 /*	$NetBSD: vasprintf.c,v 1.14 2012/03/15 18:22:30 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
19  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
21  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 #if defined(LIBC_SCCS) && !defined(lint)
32 __RCSID("$NetBSD: vasprintf.c,v 1.14 2012/03/15 18:22:30 christos Exp $");
33 #endif /* LIBC_SCCS and not lint */
34 
35 #include <assert.h>
36 #include <errno.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include "reentrant.h"
40 #include "local.h"
41 
42 int
43 vasprintf(char **str, const char *fmt, va_list ap)
44 {
45 	int ret;
46 	FILE f;
47 	struct __sfileext fext;
48 	unsigned char *_base;
49 
50 	_DIAGASSERT(str != NULL);
51 	_DIAGASSERT(fmt != NULL);
52 
53 	_FILEEXT_SETUP(&f, &fext);
54 	f._file = -1;
55 	f._flags = __SWR | __SSTR | __SALC;
56 	f._bf._base = f._p = (unsigned char *)malloc(128);
57 	if (f._bf._base == NULL)
58 		goto err;
59 	f._bf._size = f._w = 127;		/* Leave room for the NUL */
60 	ret = __vfprintf_unlocked(&f, fmt, ap);
61 	if (ret == -1)
62 		goto err;
63 	*f._p = '\0';
64 	_base = realloc(f._bf._base, (size_t)(ret + 1));
65 	if (_base == NULL)
66 		goto err;
67 	*str = (char *)_base;
68 	return ret;
69 
70 err:
71 	if (f._bf._base)
72 		free(f._bf._base);
73 	*str = NULL;
74 	errno = ENOMEM;
75 	return -1;
76 }
77