1/*
2 * Copyright (c) 2000-2001 Proofpoint, 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#include <sm/gen.h>
16SM_RCSID("@(#)$Id: vsnprintf.c,v 1.24 2013-11-22 20:51:44 ca Exp $")
17#include <limits.h>
18#include <sm/io.h>
19#include "local.h"
20
21/*
22**  SM_VSNPRINTF -- format data for "output" into a string
23**
24**	Assigned 'str' to a "fake" file pointer. This allows common
25**	o/p formatting function sm_vprintf() to be used.
26**
27**	Parameters:
28**		str -- location for output
29**		n -- maximum size for o/p
30**		fmt -- format directives
31**		ap -- data unit vectors for use by 'fmt'
32**
33**	Results:
34**		result from sm_io_vfprintf()
35**
36**	Side Effects:
37**		Limits the size ('n') to INT_MAX.
38*/
39
40int
41sm_vsnprintf(str, n, fmt, ap)
42	char *str;
43	size_t n;
44	const char *fmt;
45	SM_VA_LOCAL_DECL
46{
47	int ret;
48	char dummy;
49	SM_FILE_T fake;
50
51	/* While snprintf(3) specifies size_t stdio uses an int internally */
52	if (n > INT_MAX)
53		n = INT_MAX;
54
55	/* Stdio internals do not deal correctly with zero length buffer */
56	if (n == 0)
57	{
58		str = &dummy;
59		n = 1;
60	}
61	fake.sm_magic = SmFileMagic;
62	fake.f_timeout = SM_TIME_FOREVER;
63	fake.f_timeoutstate = SM_TIME_BLOCK;
64	fake.f_file = -1;
65	fake.f_flags = SMWR | SMSTR;
66	fake.f_bf.smb_base = fake.f_p = (unsigned char *)str;
67	fake.f_bf.smb_size = fake.f_w = n - 1;
68	fake.f_close = NULL;
69	fake.f_open = NULL;
70	fake.f_read = NULL;
71	fake.f_write = NULL;
72	fake.f_seek = NULL;
73	fake.f_setinfo = fake.f_getinfo = NULL;
74	fake.f_type = "sm_vsnprintf:fake";
75	ret = sm_io_vfprintf(&fake, SM_TIME_FOREVER, fmt, ap);
76	*fake.f_p = 0;
77	return ret;
78}
79