xref: /illumos-gate/usr/src/lib/libc/port/print/snprintf.c (revision 7c478bd9)
1*7c478bd9Sstevel@tonic-gate /*
2*7c478bd9Sstevel@tonic-gate  * CDDL HEADER START
3*7c478bd9Sstevel@tonic-gate  *
4*7c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*7c478bd9Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*7c478bd9Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*7c478bd9Sstevel@tonic-gate  * with the License.
8*7c478bd9Sstevel@tonic-gate  *
9*7c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*7c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*7c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*7c478bd9Sstevel@tonic-gate  * and limitations under the License.
13*7c478bd9Sstevel@tonic-gate  *
14*7c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*7c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*7c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*7c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*7c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*7c478bd9Sstevel@tonic-gate  *
20*7c478bd9Sstevel@tonic-gate  * CDDL HEADER END
21*7c478bd9Sstevel@tonic-gate  */
22*7c478bd9Sstevel@tonic-gate /*
23*7c478bd9Sstevel@tonic-gate  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24*7c478bd9Sstevel@tonic-gate  * Use is subject to license terms.
25*7c478bd9Sstevel@tonic-gate  */
26*7c478bd9Sstevel@tonic-gate 
27*7c478bd9Sstevel@tonic-gate /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28*7c478bd9Sstevel@tonic-gate /*	  All Rights Reserved	*/
29*7c478bd9Sstevel@tonic-gate 
30*7c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
31*7c478bd9Sstevel@tonic-gate 
32*7c478bd9Sstevel@tonic-gate #include "synonyms.h"
33*7c478bd9Sstevel@tonic-gate #include <mtlib.h>
34*7c478bd9Sstevel@tonic-gate #include <stdarg.h>
35*7c478bd9Sstevel@tonic-gate #include <values.h>
36*7c478bd9Sstevel@tonic-gate #include <thread.h>
37*7c478bd9Sstevel@tonic-gate #include <synch.h>
38*7c478bd9Sstevel@tonic-gate #include <errno.h>
39*7c478bd9Sstevel@tonic-gate #include <sys/types.h>
40*7c478bd9Sstevel@tonic-gate #include "print.h"
41*7c478bd9Sstevel@tonic-gate #include "libc.h"
42*7c478bd9Sstevel@tonic-gate 
43*7c478bd9Sstevel@tonic-gate /*VARARGS2*/
44*7c478bd9Sstevel@tonic-gate int
45*7c478bd9Sstevel@tonic-gate snprintf(char *string, size_t n, const char *format, ...)
46*7c478bd9Sstevel@tonic-gate {
47*7c478bd9Sstevel@tonic-gate 	ssize_t count;
48*7c478bd9Sstevel@tonic-gate 	FILE siop;
49*7c478bd9Sstevel@tonic-gate 	va_list ap;
50*7c478bd9Sstevel@tonic-gate 	size_t	max = MAXINT;
51*7c478bd9Sstevel@tonic-gate 	unsigned char tmpbuf[1]; /* dummy buffer for _doprnt() if NULL string */
52*7c478bd9Sstevel@tonic-gate 
53*7c478bd9Sstevel@tonic-gate 	siop._cnt = n - 1;
54*7c478bd9Sstevel@tonic-gate 	siop._base = siop._ptr = (unsigned char *)string;
55*7c478bd9Sstevel@tonic-gate 	siop._flag = _IOREAD;   /* distinguish dummy file descriptor */
56*7c478bd9Sstevel@tonic-gate #ifdef _LP64
57*7c478bd9Sstevel@tonic-gate 	/*
58*7c478bd9Sstevel@tonic-gate 	 * _bufend() (_realbufend()) should return NULL for v/snprintf,
59*7c478bd9Sstevel@tonic-gate 	 * so PUT() macro in _doprnt() will bounds check.  For 32-bit,
60*7c478bd9Sstevel@tonic-gate 	 * there is no _end field, and _realbufend() will return NULL
61*7c478bd9Sstevel@tonic-gate 	 * since it cannot find the dummy FILE structure in the linked
62*7c478bd9Sstevel@tonic-gate 	 * list of FILE strucutres.  See bug 4274368.
63*7c478bd9Sstevel@tonic-gate 	 */
64*7c478bd9Sstevel@tonic-gate 	siop._end = NULL;
65*7c478bd9Sstevel@tonic-gate #endif	/* _LP64 */
66*7c478bd9Sstevel@tonic-gate 
67*7c478bd9Sstevel@tonic-gate 	if (n == 0) {
68*7c478bd9Sstevel@tonic-gate 		/*
69*7c478bd9Sstevel@tonic-gate 		 * When n==0, string may be NULL, so always use tmpbuf to
70*7c478bd9Sstevel@tonic-gate 		 * guard for this case.  No bytes should be transmitted to
71*7c478bd9Sstevel@tonic-gate 		 * the buffer when n==0, so using tmpbuf instead of string
72*7c478bd9Sstevel@tonic-gate 		 * (ie, if string is not NULL) should not matter.
73*7c478bd9Sstevel@tonic-gate 		 */
74*7c478bd9Sstevel@tonic-gate 		siop._base = siop._ptr = tmpbuf;
75*7c478bd9Sstevel@tonic-gate 		siop._cnt = 0;
76*7c478bd9Sstevel@tonic-gate 	} else if (n > max) {
77*7c478bd9Sstevel@tonic-gate 		errno = EOVERFLOW;
78*7c478bd9Sstevel@tonic-gate 		return (EOF);
79*7c478bd9Sstevel@tonic-gate 	}
80*7c478bd9Sstevel@tonic-gate 
81*7c478bd9Sstevel@tonic-gate 	va_start(ap, format);
82*7c478bd9Sstevel@tonic-gate 	count = _ndoprnt(format, ap, &siop, 0);
83*7c478bd9Sstevel@tonic-gate 	va_end(ap);
84*7c478bd9Sstevel@tonic-gate 
85*7c478bd9Sstevel@tonic-gate 	*siop._ptr = '\0';   /* plant terminating null character */
86*7c478bd9Sstevel@tonic-gate 
87*7c478bd9Sstevel@tonic-gate 	if (count == EOF)
88*7c478bd9Sstevel@tonic-gate 		return (EOF);
89*7c478bd9Sstevel@tonic-gate 
90*7c478bd9Sstevel@tonic-gate 	/* overflow check */
91*7c478bd9Sstevel@tonic-gate 	if ((size_t)count > max) {
92*7c478bd9Sstevel@tonic-gate 		errno = EOVERFLOW;
93*7c478bd9Sstevel@tonic-gate 		return (EOF);
94*7c478bd9Sstevel@tonic-gate 	} else {
95*7c478bd9Sstevel@tonic-gate 		return ((int)count);
96*7c478bd9Sstevel@tonic-gate 	}
97*7c478bd9Sstevel@tonic-gate }
98*7c478bd9Sstevel@tonic-gate 
99*7c478bd9Sstevel@tonic-gate #ifndef _LP64
100*7c478bd9Sstevel@tonic-gate 
101*7c478bd9Sstevel@tonic-gate /*
102*7c478bd9Sstevel@tonic-gate  * 32-bit shadow function of snprintf().
103*7c478bd9Sstevel@tonic-gate  * When using the c89 compiler to build 32-bit applications, the size
104*7c478bd9Sstevel@tonic-gate  * of intmax_t is 32-bits, otherwise the size of intmax_t is 64-bits.
105*7c478bd9Sstevel@tonic-gate  * The shadow function uses 32-bit size of intmax_t for %j conversion.
106*7c478bd9Sstevel@tonic-gate  * The #pragma redefine_extname in <stdio.h> selects the proper routine
107*7c478bd9Sstevel@tonic-gate  * at compile time for the user application.
108*7c478bd9Sstevel@tonic-gate  * NOTE: this function is only available in the 32-bit library.
109*7c478bd9Sstevel@tonic-gate  */
110*7c478bd9Sstevel@tonic-gate 
111*7c478bd9Sstevel@tonic-gate int
112*7c478bd9Sstevel@tonic-gate _snprintf_c89(char *string, size_t n, const char *format, ...)
113*7c478bd9Sstevel@tonic-gate {
114*7c478bd9Sstevel@tonic-gate 	ssize_t count;
115*7c478bd9Sstevel@tonic-gate 	va_list ap;
116*7c478bd9Sstevel@tonic-gate 
117*7c478bd9Sstevel@tonic-gate 	va_start(ap, format);
118*7c478bd9Sstevel@tonic-gate 	count = _vsnprintf_c89(string, n, format, ap);
119*7c478bd9Sstevel@tonic-gate 	va_end(ap);
120*7c478bd9Sstevel@tonic-gate 	return ((int)count);
121*7c478bd9Sstevel@tonic-gate }
122*7c478bd9Sstevel@tonic-gate 
123*7c478bd9Sstevel@tonic-gate #endif	/* _LP64 */
124