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>
18 SM_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
48 int
49 #if SM_VA_STD
sm_snprintf(char * str,size_t n,char const * fmt,...)50 sm_snprintf(char *str, size_t n, char const *fmt, ...)
51 #else /* SM_VA_STD */
52 sm_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