1/*
2 * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
3 *      All rights reserved.
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * By using this file, you agree to the terms and conditions set
11 * forth in the LICENSE file which can be found at the top level of
12 * the sendmail distribution.
13 */
14
15#pragma ident	"%Z%%M%	%I%	%E% SMI"
16
17#include <sm/gen.h>
18SM_RCSID("@(#)$Id: vsnprintf.c,v 1.21 2001/03/04 23:28:41 ca Exp $")
19#include <limits.h>
20#include <sm/io.h>
21#include "local.h"
22
23/*
24**  SM_VSNPRINTF -- format data for "output" into a string
25**
26**	Assigned 'str' to a "fake" file pointer. This allows common
27**	o/p formatting function sm_vprintf() to be used.
28**
29**	Parameters:
30**		str -- location for output
31**		n -- maximum size for o/p
32**		fmt -- format directives
33**		ap -- data unit vectors for use by 'fmt'
34**
35**	Results:
36**		result from sm_io_vfprintf()
37**
38**	Side Effects:
39**		Limits the size ('n') to INT_MAX.
40*/
41
42int
43sm_vsnprintf(str, n, fmt, ap)
44	char *str;
45	size_t n;
46	const char *fmt;
47	SM_VA_LOCAL_DECL
48{
49	int ret;
50	char dummy;
51	SM_FILE_T fake;
52
53	/* While snprintf(3) specifies size_t stdio uses an int internally */
54	if (n > INT_MAX)
55		n = INT_MAX;
56
57	/* Stdio internals do not deal correctly with zero length buffer */
58	if (n == 0)
59	{
60		str = &dummy;
61		n = 1;
62	}
63	fake.sm_magic = SmFileMagic;
64	fake.f_timeout = SM_TIME_FOREVER;
65	fake.f_timeoutstate = SM_TIME_BLOCK;
66	fake.f_file = -1;
67	fake.f_flags = SMWR | SMSTR;
68	fake.f_bf.smb_base = fake.f_p = (unsigned char *)str;
69	fake.f_bf.smb_size = fake.f_w = n - 1;
70	fake.f_close = NULL;
71	fake.f_open = NULL;
72	fake.f_read = NULL;
73	fake.f_write = NULL;
74	fake.f_seek = NULL;
75	fake.f_setinfo = fake.f_getinfo = NULL;
76	fake.f_type = "sm_vsnprintf:fake";
77	ret = sm_io_vfprintf(&fake, SM_TIME_FOREVER, fmt, ap);
78	*fake.f_p = 0;
79	return ret;
80}
81