xref: /freebsd/crypto/openssh/openbsd-compat/bsd-asprintf.c (revision d056fa046c6a91b90cd98165face0e42a33a5173)
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 #ifndef HAVE_VASPRINTF
23 
24 #ifndef VA_COPY
25 # ifdef HAVE_VA_COPY
26 #  define VA_COPY(dest, src) va_copy(dest, src)
27 # else
28 #  ifdef HAVE___VA_COPY
29 #   define VA_COPY(dest, src) __va_copy(dest, src)
30 #  else
31 #   define VA_COPY(dest, src) (dest) = (src)
32 #  endif
33 # endif
34 #endif
35 
36 #define INIT_SZ	128
37 
38 int vasprintf(char **str, const char *fmt, va_list ap)
39 {
40 	int ret = -1;
41 	va_list ap2;
42 	char *string, *newstr;
43 	size_t len;
44 
45 	VA_COPY(ap2, ap);
46 	if ((string = malloc(INIT_SZ)) == NULL)
47 		goto fail;
48 
49 	ret = vsnprintf(string, INIT_SZ, fmt, ap2);
50 	if (ret >= 0 && ret < INIT_SZ) { /* succeeded with initial alloc */
51 		*str = string;
52 	} else if (ret == INT_MAX) { /* shouldn't happen */
53 		goto fail;
54 	} else {	/* bigger than initial, realloc allowing for nul */
55 		len = (size_t)ret + 1;
56 		if ((newstr = realloc(string, len)) == NULL) {
57 			free(string);
58 			goto fail;
59 		} else {
60 			va_end(ap2);
61 			VA_COPY(ap2, ap);
62 			ret = vsnprintf(newstr, len, fmt, ap2);
63 			if (ret >= 0 && (size_t)ret < len) {
64 				*str = newstr;
65 			} else { /* failed with realloc'ed string, give up */
66 				free(newstr);
67 				goto fail;
68 			}
69 		}
70 	}
71 	va_end(ap2);
72 	return (ret);
73 
74 fail:
75 	*str = NULL;
76 	errno = ENOMEM;
77 	va_end(ap2);
78 	return (-1);
79 }
80 #endif
81 
82 #ifndef HAVE_ASPRINTF
83 int asprintf(char **str, const char *fmt, ...)
84 {
85 	va_list ap;
86 	int ret;
87 
88 	*str = NULL;
89 	va_start(ap, fmt);
90 	ret = vasprintf(str, fmt, ap);
91 	va_end(ap);
92 
93 	return ret;
94 }
95 #endif
96