xref: /freebsd/crypto/openssh/openbsd-compat/bsd-asprintf.c (revision 43a5ec4eb41567cc92586503212743d89686d78f)
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 <stdlib.h>
36 
37 #define INIT_SZ	128
38 
39 int
40 vasprintf(char **str, const char *fmt, va_list ap)
41 {
42 	int ret = -1;
43 	va_list ap2;
44 	char *string, *newstr;
45 	size_t len;
46 
47 	VA_COPY(ap2, ap);
48 	if ((string = malloc(INIT_SZ)) == NULL)
49 		goto fail;
50 
51 	ret = vsnprintf(string, INIT_SZ, fmt, ap2);
52 	if (ret >= 0 && ret < INIT_SZ) { /* succeeded with initial alloc */
53 		*str = string;
54 	} else if (ret == INT_MAX || ret < 0) { /* Bad length */
55 		free(string);
56 		goto fail;
57 	} else {	/* bigger than initial, realloc allowing for nul */
58 		len = (size_t)ret + 1;
59 		if ((newstr = realloc(string, len)) == NULL) {
60 			free(string);
61 			goto fail;
62 		} else {
63 			va_end(ap2);
64 			VA_COPY(ap2, ap);
65 			ret = vsnprintf(newstr, len, fmt, ap2);
66 			if (ret >= 0 && (size_t)ret < len) {
67 				*str = newstr;
68 			} else { /* failed with realloc'ed string, give up */
69 				free(newstr);
70 				goto fail;
71 			}
72 		}
73 	}
74 	va_end(ap2);
75 	return (ret);
76 
77 fail:
78 	*str = NULL;
79 	errno = ENOMEM;
80 	va_end(ap2);
81 	return (-1);
82 }
83 #endif
84 
85 #ifndef HAVE_ASPRINTF
86 int asprintf(char **str, const char *fmt, ...)
87 {
88 	va_list ap;
89 	int ret;
90 
91 	*str = NULL;
92 	va_start(ap, fmt);
93 	ret = vasprintf(str, fmt, ap);
94 	va_end(ap);
95 
96 	return ret;
97 }
98 #endif
99