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 #include "lint.h"
31 #include <mtlib.h>
32 #include <stdarg.h>
33 #include <values.h>
34 #include <thread.h>
35 #include <synch.h>
36 #include <errno.h>
37 #include <sys/types.h>
38 #include "print.h"
39 #include "libc.h"
40
41 /*VARARGS2*/
42 int
snprintf(char * string,size_t n,const char * format,...)43 snprintf(char *string, size_t n, const char *format, ...)
44 {
45 ssize_t count;
46 FILE siop;
47 va_list ap;
48 size_t max = MAXINT;
49 unsigned char tmpbuf[1]; /* dummy buffer for _doprnt() if NULL string */
50
51 siop._cnt = n - 1;
52 siop._base = siop._ptr = (unsigned char *)string;
53 siop._flag = _IOREAD; /* distinguish dummy file descriptor */
54 #ifdef _LP64
55 /*
56 * _bufend() (_realbufend()) should return NULL for v/snprintf,
57 * so PUT() macro in _doprnt() will bounds check. For 32-bit,
58 * there is no _end field, and _realbufend() will return NULL
59 * since it cannot find the dummy FILE structure in the linked
60 * list of FILE strucutres. See bug 4274368.
61 */
62 siop._end = NULL;
63 #endif /* _LP64 */
64
65 if (n == 0) {
66 /*
67 * When n==0, string may be NULL, so always use tmpbuf to
68 * guard for this case. No bytes should be transmitted to
69 * the buffer when n==0, so using tmpbuf instead of string
70 * (ie, if string is not NULL) should not matter.
71 */
72 siop._base = siop._ptr = tmpbuf;
73 siop._cnt = 0;
74 } else if (n > max) {
75 errno = EOVERFLOW;
76 return (EOF);
77 }
78
79 va_start(ap, format);
80 count = _ndoprnt(format, ap, &siop, 0);
81 va_end(ap);
82
83 *siop._ptr = '\0'; /* plant terminating null character */
84
85 if (count == EOF)
86 return (EOF);
87
88 /* overflow check */
89 if ((size_t)count > max) {
90 errno = EOVERFLOW;
91 return (EOF);
92 } else {
93 return ((int)count);
94 }
95 }
96
97 #ifndef _LP64
98
99 /*
100 * 32-bit shadow function of snprintf().
101 * When using the c89 compiler to build 32-bit applications, the size
102 * of intmax_t is 32-bits, otherwise the size of intmax_t is 64-bits.
103 * The shadow function uses 32-bit size of intmax_t for %j conversion.
104 * The #pragma redefine_extname in <stdio.h> selects the proper routine
105 * at compile time for the user application.
106 * NOTE: this function is only available in the 32-bit library.
107 */
108
109 int
_snprintf_c89(char * string,size_t n,const char * format,...)110 _snprintf_c89(char *string, size_t n, const char *format, ...)
111 {
112 ssize_t count;
113 va_list ap;
114
115 va_start(ap, format);
116 count = _vsnprintf_c89(string, n, format, ap);
117 va_end(ap);
118 return ((int)count);
119 }
120
121 #endif /* _LP64 */
122