xref: /titanic_41/usr/src/cmd/sendmail/libsm/vsnprintf.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
1*7c478bd9Sstevel@tonic-gate /*
2*7c478bd9Sstevel@tonic-gate  * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
3*7c478bd9Sstevel@tonic-gate  *      All rights reserved.
4*7c478bd9Sstevel@tonic-gate  * Copyright (c) 1990, 1993
5*7c478bd9Sstevel@tonic-gate  *	The Regents of the University of California.  All rights reserved.
6*7c478bd9Sstevel@tonic-gate  *
7*7c478bd9Sstevel@tonic-gate  * This code is derived from software contributed to Berkeley by
8*7c478bd9Sstevel@tonic-gate  * Chris Torek.
9*7c478bd9Sstevel@tonic-gate  *
10*7c478bd9Sstevel@tonic-gate  * By using this file, you agree to the terms and conditions set
11*7c478bd9Sstevel@tonic-gate  * forth in the LICENSE file which can be found at the top level of
12*7c478bd9Sstevel@tonic-gate  * the sendmail distribution.
13*7c478bd9Sstevel@tonic-gate  */
14*7c478bd9Sstevel@tonic-gate 
15*7c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
16*7c478bd9Sstevel@tonic-gate 
17*7c478bd9Sstevel@tonic-gate #include <sm/gen.h>
18*7c478bd9Sstevel@tonic-gate SM_RCSID("@(#)$Id: vsnprintf.c,v 1.21 2001/03/04 23:28:41 ca Exp $")
19*7c478bd9Sstevel@tonic-gate #include <limits.h>
20*7c478bd9Sstevel@tonic-gate #include <sm/io.h>
21*7c478bd9Sstevel@tonic-gate #include "local.h"
22*7c478bd9Sstevel@tonic-gate 
23*7c478bd9Sstevel@tonic-gate /*
24*7c478bd9Sstevel@tonic-gate **  SM_VSNPRINTF -- format data for "output" into a string
25*7c478bd9Sstevel@tonic-gate **
26*7c478bd9Sstevel@tonic-gate **	Assigned 'str' to a "fake" file pointer. This allows common
27*7c478bd9Sstevel@tonic-gate **	o/p formatting function sm_vprintf() to be used.
28*7c478bd9Sstevel@tonic-gate **
29*7c478bd9Sstevel@tonic-gate **	Parameters:
30*7c478bd9Sstevel@tonic-gate **		str -- location for output
31*7c478bd9Sstevel@tonic-gate **		n -- maximum size for o/p
32*7c478bd9Sstevel@tonic-gate **		fmt -- format directives
33*7c478bd9Sstevel@tonic-gate **		ap -- data unit vectors for use by 'fmt'
34*7c478bd9Sstevel@tonic-gate **
35*7c478bd9Sstevel@tonic-gate **	Results:
36*7c478bd9Sstevel@tonic-gate **		result from sm_io_vfprintf()
37*7c478bd9Sstevel@tonic-gate **
38*7c478bd9Sstevel@tonic-gate **	Side Effects:
39*7c478bd9Sstevel@tonic-gate **		Limits the size ('n') to INT_MAX.
40*7c478bd9Sstevel@tonic-gate */
41*7c478bd9Sstevel@tonic-gate 
42*7c478bd9Sstevel@tonic-gate int
43*7c478bd9Sstevel@tonic-gate sm_vsnprintf(str, n, fmt, ap)
44*7c478bd9Sstevel@tonic-gate 	char *str;
45*7c478bd9Sstevel@tonic-gate 	size_t n;
46*7c478bd9Sstevel@tonic-gate 	const char *fmt;
47*7c478bd9Sstevel@tonic-gate 	SM_VA_LOCAL_DECL
48*7c478bd9Sstevel@tonic-gate {
49*7c478bd9Sstevel@tonic-gate 	int ret;
50*7c478bd9Sstevel@tonic-gate 	char dummy;
51*7c478bd9Sstevel@tonic-gate 	SM_FILE_T fake;
52*7c478bd9Sstevel@tonic-gate 
53*7c478bd9Sstevel@tonic-gate 	/* While snprintf(3) specifies size_t stdio uses an int internally */
54*7c478bd9Sstevel@tonic-gate 	if (n > INT_MAX)
55*7c478bd9Sstevel@tonic-gate 		n = INT_MAX;
56*7c478bd9Sstevel@tonic-gate 
57*7c478bd9Sstevel@tonic-gate 	/* Stdio internals do not deal correctly with zero length buffer */
58*7c478bd9Sstevel@tonic-gate 	if (n == 0)
59*7c478bd9Sstevel@tonic-gate 	{
60*7c478bd9Sstevel@tonic-gate 		str = &dummy;
61*7c478bd9Sstevel@tonic-gate 		n = 1;
62*7c478bd9Sstevel@tonic-gate 	}
63*7c478bd9Sstevel@tonic-gate 	fake.sm_magic = SmFileMagic;
64*7c478bd9Sstevel@tonic-gate 	fake.f_timeout = SM_TIME_FOREVER;
65*7c478bd9Sstevel@tonic-gate 	fake.f_timeoutstate = SM_TIME_BLOCK;
66*7c478bd9Sstevel@tonic-gate 	fake.f_file = -1;
67*7c478bd9Sstevel@tonic-gate 	fake.f_flags = SMWR | SMSTR;
68*7c478bd9Sstevel@tonic-gate 	fake.f_bf.smb_base = fake.f_p = (unsigned char *)str;
69*7c478bd9Sstevel@tonic-gate 	fake.f_bf.smb_size = fake.f_w = n - 1;
70*7c478bd9Sstevel@tonic-gate 	fake.f_close = NULL;
71*7c478bd9Sstevel@tonic-gate 	fake.f_open = NULL;
72*7c478bd9Sstevel@tonic-gate 	fake.f_read = NULL;
73*7c478bd9Sstevel@tonic-gate 	fake.f_write = NULL;
74*7c478bd9Sstevel@tonic-gate 	fake.f_seek = NULL;
75*7c478bd9Sstevel@tonic-gate 	fake.f_setinfo = fake.f_getinfo = NULL;
76*7c478bd9Sstevel@tonic-gate 	fake.f_type = "sm_vsnprintf:fake";
77*7c478bd9Sstevel@tonic-gate 	ret = sm_io_vfprintf(&fake, SM_TIME_FOREVER, fmt, ap);
78*7c478bd9Sstevel@tonic-gate 	*fake.f_p = 0;
79*7c478bd9Sstevel@tonic-gate 	return ret;
80*7c478bd9Sstevel@tonic-gate }
81