xref: /freebsd/lib/libc/stdio/asprintf.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
1 /*	$OpenBSD: asprintf.c,v 1.8 2002/02/19 19:39:36 millert 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 __FBSDID("$FreeBSD$");
32 
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <errno.h>
36 #include <stdarg.h>
37 
38 #include "local.h"
39 
40 int
41 asprintf(char **str, char const *fmt, ...)
42 {
43 	int ret;
44 	va_list ap;
45 	FILE f;
46 	struct __sFILEX ext;
47 
48 	f._file = -1;
49 	f._flags = __SWR | __SSTR | __SALC;
50 	f._bf._base = f._p = (unsigned char *)malloc(128);
51 	if (f._bf._base == NULL) {
52 		*str = NULL;
53 		errno = ENOMEM;
54 		return (-1);
55 	}
56 	f._bf._size = f._w = 127;		/* Leave room for the NUL */
57 	f._extra = &ext;
58 	INITEXTRA(&f);
59 	va_start(ap, fmt);
60 	ret = __vfprintf(&f, fmt, ap);		/* Use unlocked __vfprintf */
61 	va_end(ap);
62 	if (ret < 0) {
63 		free(f._bf._base);
64 		*str = NULL;
65 		errno = ENOMEM;
66 		return (-1);
67 	}
68 	*f._p = '\0';
69 	*str = (char *)f._bf._base;
70 	return (ret);
71 }
72