1 /* $OpenBSD: asprintf.c,v 1.26 2019/01/25 00:19:25 millert Exp $ */
2
3 /*
4 * Copyright (c) 1997 Todd C. Miller <millert@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <errno.h>
23 #include <stdarg.h>
24 #include <unistd.h>
25 #include "local.h"
26
27 #define INITIAL_SIZE 128
28
29 int
asprintf(char ** str,const char * fmt,...)30 asprintf(char **str, const char *fmt, ...)
31 {
32 int ret;
33 va_list ap;
34 FILE f;
35 struct __sfileext fext;
36 const int pgsz = getpagesize();
37
38 _FILEEXT_SETUP(&f, &fext);
39 f._file = -1;
40 f._flags = __SWR | __SSTR | __SALC;
41 f._bf._base = f._p = malloc(INITIAL_SIZE);
42 if (f._bf._base == NULL)
43 goto err;
44 f._bf._size = f._w = INITIAL_SIZE - 1; /* leave room for the NUL */
45 va_start(ap, fmt);
46 ret = __vfprintf(&f, fmt, ap);
47 va_end(ap);
48 if (ret == -1)
49 goto err;
50 *f._p = '\0';
51 if (ret + 1 > INITIAL_SIZE && ret + 1 < pgsz / 2) {
52 /* midsize allocations can try to conserve memory */
53 unsigned char *_base = recallocarray(f._bf._base,
54 f._bf._size + 1, ret + 1, 1);
55
56 if (_base == NULL)
57 goto err;
58 *str = (char *)_base;
59 } else
60 *str = (char *)f._bf._base;
61 return (ret);
62
63 err:
64 free(f._bf._base);
65 f._bf._base = NULL;
66 *str = NULL;
67 errno = ENOMEM;
68 return (-1);
69 }
70 DEF_WEAK(asprintf);
71