1 /* $OpenBSD: vasprintf.c,v 1.23 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 <unistd.h>
24 #include "local.h"
25
26 #define INITIAL_SIZE 128
27
28 int
vasprintf(char ** str,const char * fmt,__va_list ap)29 vasprintf(char **str, const char *fmt, __va_list ap)
30 {
31 int ret;
32 FILE f;
33 struct __sfileext fext;
34 const int pgsz = getpagesize();
35
36 _FILEEXT_SETUP(&f, &fext);
37 f._file = -1;
38 f._flags = __SWR | __SSTR | __SALC;
39 f._bf._base = f._p = malloc(INITIAL_SIZE);
40 if (f._bf._base == NULL)
41 goto err;
42 f._bf._size = f._w = INITIAL_SIZE - 1; /* leave room for the NUL */
43 ret = __vfprintf(&f, fmt, ap);
44 if (ret == -1)
45 goto err;
46 *f._p = '\0';
47 if (ret + 1 > INITIAL_SIZE && ret + 1 < pgsz / 2) {
48 /* midsize allocations can try to conserve memory */
49 unsigned char *_base = recallocarray(f._bf._base,
50 f._bf._size + 1, ret + 1, 1);
51
52 if (_base == NULL)
53 goto err;
54 *str = (char *)_base;
55 } else
56 *str = (char *)f._bf._base;
57 return (ret);
58
59 err:
60 free(f._bf._base);
61 f._bf._base = NULL;
62 *str = NULL;
63 errno = ENOMEM;
64 return (-1);
65 }
66 DEF_WEAK(vasprintf);
67