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: snprintf.c,v 1.24 2006/10/12 21:50:10 ca Exp $")
19#include <limits.h>
20#include <sm/varargs.h>
21#include <sm/io.h>
22#include <sm/string.h>
23#include "local.h"
24
25/*
26**  SM_SNPRINTF -- format a string to a memory location of restricted size
27**
28**	Parameters:
29**		str -- memory location to place formatted string
30**		n -- size of buffer pointed to by str, capped to
31**			a maximum of INT_MAX
32**		fmt -- the formatting directives
33**		... -- the data to satisfy the formatting
34**
35**	Returns:
36**		Failure: -1
37**		Success: number of bytes that would have been written
38**			to str, not including the trailing '\0',
39**			up to a maximum of INT_MAX, as if there was
40**			no buffer size limitation.  If the result >= n
41**			then the output was truncated.
42**
43**	Side Effects:
44**		If n > 0, then between 0 and n-1 bytes of formatted output
45**		are written into 'str', followed by a '\0'.
46*/
47
48int
49#if SM_VA_STD
50sm_snprintf(char *str, size_t n, char const *fmt, ...)
51#else /* SM_VA_STD */
52sm_snprintf(str, n, fmt, va_alist)
53	char *str;
54	size_t n;
55	char *fmt;
56	va_dcl
57#endif /* SM_VA_STD */
58{
59	int ret;
60	SM_VA_LOCAL_DECL
61	SM_FILE_T fake;
62
63	/* While snprintf(3) specifies size_t stdio uses an int internally */
64	if (n > INT_MAX)
65		n = INT_MAX;
66	SM_VA_START(ap, fmt);
67
68	/* XXX put this into a static? */
69	fake.sm_magic = SmFileMagic;
70	fake.f_file = -1;
71	fake.f_flags = SMWR | SMSTR;
72	fake.f_cookie = &fake;
73	fake.f_bf.smb_base = fake.f_p = (unsigned char *)str;
74	fake.f_bf.smb_size = fake.f_w = n ? n - 1 : 0;
75	fake.f_timeout = SM_TIME_FOREVER;
76	fake.f_timeoutstate = SM_TIME_BLOCK;
77	fake.f_close = NULL;
78	fake.f_open = NULL;
79	fake.f_read = NULL;
80	fake.f_write = NULL;
81	fake.f_seek = NULL;
82	fake.f_setinfo = fake.f_getinfo = NULL;
83	fake.f_type = "sm_snprintf:fake";
84	ret = sm_io_vfprintf(&fake, SM_TIME_FOREVER, fmt, ap);
85	if (n > 0)
86		*fake.f_p = '\0';
87	SM_VA_END(ap);
88	return ret;
89}
90