xref: /freebsd/crypto/openssh/openbsd-compat/bsd-asprintf.c (revision 02e9120893770924227138ba49df1edb3896112a)
1 /*
2  * Copyright (c) 2004 Darren Tucker.
3  *
4  * Based originally on asprintf.c from OpenBSD:
5  * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include "includes.h"
21 
22 /*
23  * Don't let systems with broken printf(3) avoid our replacements
24  * via asprintf(3)/vasprintf(3) calling libc internally.
25  */
26 #if defined(BROKEN_SNPRINTF)
27 # undef HAVE_VASPRINTF
28 # undef HAVE_ASPRINTF
29 #endif
30 
31 #ifndef HAVE_VASPRINTF
32 
33 #include <errno.h>
34 #include <stdarg.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 
38 #define INIT_SZ	128
39 
40 int
41 vasprintf(char **str, const char *fmt, va_list ap)
42 {
43 	int ret = -1;
44 	va_list ap2;
45 	char *string, *newstr;
46 	size_t len;
47 
48 	VA_COPY(ap2, ap);
49 	if ((string = malloc(INIT_SZ)) == NULL)
50 		goto fail;
51 
52 	ret = vsnprintf(string, INIT_SZ, fmt, ap2);
53 	if (ret >= 0 && ret < INIT_SZ) { /* succeeded with initial alloc */
54 		*str = string;
55 	} else if (ret == INT_MAX || ret < 0) { /* Bad length */
56 		free(string);
57 		goto fail;
58 	} else {	/* bigger than initial, realloc allowing for nul */
59 		len = (size_t)ret + 1;
60 		if ((newstr = realloc(string, len)) == NULL) {
61 			free(string);
62 			goto fail;
63 		} else {
64 			va_end(ap2);
65 			VA_COPY(ap2, ap);
66 			ret = vsnprintf(newstr, len, fmt, ap2);
67 			if (ret >= 0 && (size_t)ret < len) {
68 				*str = newstr;
69 			} else { /* failed with realloc'ed string, give up */
70 				free(newstr);
71 				goto fail;
72 			}
73 		}
74 	}
75 	va_end(ap2);
76 	return (ret);
77 
78 fail:
79 	*str = NULL;
80 	errno = ENOMEM;
81 	va_end(ap2);
82 	return (-1);
83 }
84 #endif
85 
86 #ifndef HAVE_ASPRINTF
87 int asprintf(char **str, const char *fmt, ...)
88 {
89 	va_list ap;
90 	int ret;
91 
92 	*str = NULL;
93 	va_start(ap, fmt);
94 	ret = vasprintf(str, fmt, ap);
95 	va_end(ap);
96 
97 	return ret;
98 }
99 #endif
100