1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 #pragma ident "%Z%%M% %I% %E% SMI"
31
32 #include "lint.h"
33 #include <mtlib.h>
34 #include <stdarg.h>
35 #include <values.h>
36 #include <thread.h>
37 #include <synch.h>
38 #include <errno.h>
39 #include <sys/types.h>
40 #include "print.h"
41 #include "libc.h"
42
43 /*VARARGS2*/
44 int
snprintf(char * string,size_t n,const char * format,...)45 snprintf(char *string, size_t n, const char *format, ...)
46 {
47 ssize_t count;
48 FILE siop;
49 va_list ap;
50 size_t max = MAXINT;
51 unsigned char tmpbuf[1]; /* dummy buffer for _doprnt() if NULL string */
52
53 siop._cnt = n - 1;
54 siop._base = siop._ptr = (unsigned char *)string;
55 siop._flag = _IOREAD; /* distinguish dummy file descriptor */
56 #ifdef _LP64
57 /*
58 * _bufend() (_realbufend()) should return NULL for v/snprintf,
59 * so PUT() macro in _doprnt() will bounds check. For 32-bit,
60 * there is no _end field, and _realbufend() will return NULL
61 * since it cannot find the dummy FILE structure in the linked
62 * list of FILE strucutres. See bug 4274368.
63 */
64 siop._end = NULL;
65 #endif /* _LP64 */
66
67 if (n == 0) {
68 /*
69 * When n==0, string may be NULL, so always use tmpbuf to
70 * guard for this case. No bytes should be transmitted to
71 * the buffer when n==0, so using tmpbuf instead of string
72 * (ie, if string is not NULL) should not matter.
73 */
74 siop._base = siop._ptr = tmpbuf;
75 siop._cnt = 0;
76 } else if (n > max) {
77 errno = EOVERFLOW;
78 return (EOF);
79 }
80
81 va_start(ap, format);
82 count = _ndoprnt(format, ap, &siop, 0);
83 va_end(ap);
84
85 *siop._ptr = '\0'; /* plant terminating null character */
86
87 if (count == EOF)
88 return (EOF);
89
90 /* overflow check */
91 if ((size_t)count > max) {
92 errno = EOVERFLOW;
93 return (EOF);
94 } else {
95 return ((int)count);
96 }
97 }
98
99 #ifndef _LP64
100
101 /*
102 * 32-bit shadow function of snprintf().
103 * When using the c89 compiler to build 32-bit applications, the size
104 * of intmax_t is 32-bits, otherwise the size of intmax_t is 64-bits.
105 * The shadow function uses 32-bit size of intmax_t for %j conversion.
106 * The #pragma redefine_extname in <stdio.h> selects the proper routine
107 * at compile time for the user application.
108 * NOTE: this function is only available in the 32-bit library.
109 */
110
111 int
_snprintf_c89(char * string,size_t n,const char * format,...)112 _snprintf_c89(char *string, size_t n, const char *format, ...)
113 {
114 ssize_t count;
115 va_list ap;
116
117 va_start(ap, format);
118 count = _vsnprintf_c89(string, n, format, ap);
119 va_end(ap);
120 return ((int)count);
121 }
122
123 #endif /* _LP64 */
124