1 /*
2 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
3 * Use is subject to license terms.
4 */
5
6 /*
7 * Copyright (c) 2004 Darren Tucker.
8 * Copyright 2022 Oxide Computer Company
9 *
10 * Based originally on asprintf.c from OpenBSD:
11 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
12 *
13 * Permission to use, copy, modify, and distribute this software for any
14 * purpose with or without fee is hereby granted, provided that the above
15 * copyright notice and this permission notice appear in all copies.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
18 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
20 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
21 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
22 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
23 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
24 */
25
26 #include <lint.h>
27 #include <stdio.h>
28 #include <stdarg.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <limits.h>
32 #include <errno.h>
33
34 #define INIT_SZ 128
35
36 int
vasprintf(char ** str,const char * format,va_list ap)37 vasprintf(char **str, const char *format, va_list ap)
38 {
39 char string[INIT_SZ];
40 char *newstr;
41 int ret;
42 size_t len;
43
44 *str = NULL;
45 ret = vsnprintf(string, INIT_SZ, format, ap);
46 if (ret < 0) /* retain the value of errno from vsnprintf() */
47 return (-1);
48 if (ret < INIT_SZ) {
49 len = ret + 1;
50 if ((newstr = malloc(len)) == NULL)
51 return (-1); /* retain errno from malloc() */
52 /*
53 * Prior versions of this used strlcpy. This has two problems.
54 * One, it doesn't handle embedded '\0' characters. Secondly,
55 * it's recalculating the length we already know. Please do not
56 * use a string-based copying function.
57 */
58 (void) memcpy(newstr, string, len);
59 *str = newstr;
60 return (ret);
61 }
62 /*
63 * We will perform this loop more than once only if some other
64 * thread modifies one of the vasprintf() arguments after our
65 * previous call to vsnprintf().
66 */
67 for (;;) {
68 if (ret == INT_MAX) { /* Bad length */
69 errno = ENOMEM;
70 return (-1);
71 }
72 len = ret + 1;
73 if ((newstr = malloc(len)) == NULL)
74 return (-1); /* retain errno from malloc() */
75 ret = vsnprintf(newstr, len, format, ap);
76 if (ret < 0) { /* retain errno from vsnprintf() */
77 free(newstr);
78 return (-1);
79 }
80 if (ret < len) {
81 *str = newstr;
82 return (ret);
83 }
84 free(newstr);
85 }
86 }
87
88 int
asprintf(char ** str,const char * format,...)89 asprintf(char **str, const char *format, ...)
90 {
91 va_list ap;
92 int ret;
93
94 *str = NULL;
95 va_start(ap, format);
96 ret = vasprintf(str, format, ap);
97 va_end(ap);
98
99 return (ret);
100 }
101