xref: /illumos-gate/usr/src/lib/libc/port/print/snprintf.c (revision 7257d1b4)
17c478bd9Sstevel@tonic-gate /*
27c478bd9Sstevel@tonic-gate  * CDDL HEADER START
37c478bd9Sstevel@tonic-gate  *
47c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*7257d1b4Sraf  * Common Development and Distribution License (the "License").
6*7257d1b4Sraf  * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate  *
87c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate  * and limitations under the License.
127c478bd9Sstevel@tonic-gate  *
137c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate  *
197c478bd9Sstevel@tonic-gate  * CDDL HEADER END
207c478bd9Sstevel@tonic-gate  */
227c478bd9Sstevel@tonic-gate /*
23*7257d1b4Sraf  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
247c478bd9Sstevel@tonic-gate  * Use is subject to license terms.
257c478bd9Sstevel@tonic-gate  */
277c478bd9Sstevel@tonic-gate /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
287c478bd9Sstevel@tonic-gate /*	  All Rights Reserved	*/
307c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
32*7257d1b4Sraf #include "lint.h"
337c478bd9Sstevel@tonic-gate #include <mtlib.h>
347c478bd9Sstevel@tonic-gate #include <stdarg.h>
357c478bd9Sstevel@tonic-gate #include <values.h>
367c478bd9Sstevel@tonic-gate #include <thread.h>
377c478bd9Sstevel@tonic-gate #include <synch.h>
387c478bd9Sstevel@tonic-gate #include <errno.h>
397c478bd9Sstevel@tonic-gate #include <sys/types.h>
407c478bd9Sstevel@tonic-gate #include "print.h"
417c478bd9Sstevel@tonic-gate #include "libc.h"
437c478bd9Sstevel@tonic-gate /*VARARGS2*/
447c478bd9Sstevel@tonic-gate int
snprintf(char * string,size_t n,const char * format,...)457c478bd9Sstevel@tonic-gate snprintf(char *string, size_t n, const char *format, ...)
467c478bd9Sstevel@tonic-gate {
477c478bd9Sstevel@tonic-gate 	ssize_t count;
487c478bd9Sstevel@tonic-gate 	FILE siop;
497c478bd9Sstevel@tonic-gate 	va_list ap;
507c478bd9Sstevel@tonic-gate 	size_t	max = MAXINT;
517c478bd9Sstevel@tonic-gate 	unsigned char tmpbuf[1]; /* dummy buffer for _doprnt() if NULL string */
537c478bd9Sstevel@tonic-gate 	siop._cnt = n - 1;
547c478bd9Sstevel@tonic-gate 	siop._base = siop._ptr = (unsigned char *)string;
557c478bd9Sstevel@tonic-gate 	siop._flag = _IOREAD;   /* distinguish dummy file descriptor */
567c478bd9Sstevel@tonic-gate #ifdef _LP64
577c478bd9Sstevel@tonic-gate 	/*
587c478bd9Sstevel@tonic-gate 	 * _bufend() (_realbufend()) should return NULL for v/snprintf,
597c478bd9Sstevel@tonic-gate 	 * so PUT() macro in _doprnt() will bounds check.  For 32-bit,
607c478bd9Sstevel@tonic-gate 	 * there is no _end field, and _realbufend() will return NULL
617c478bd9Sstevel@tonic-gate 	 * since it cannot find the dummy FILE structure in the linked
627c478bd9Sstevel@tonic-gate 	 * list of FILE strucutres.  See bug 4274368.
637c478bd9Sstevel@tonic-gate 	 */
647c478bd9Sstevel@tonic-gate 	siop._end = NULL;
657c478bd9Sstevel@tonic-gate #endif	/* _LP64 */
677c478bd9Sstevel@tonic-gate 	if (n == 0) {
687c478bd9Sstevel@tonic-gate 		/*
697c478bd9Sstevel@tonic-gate 		 * When n==0, string may be NULL, so always use tmpbuf to
707c478bd9Sstevel@tonic-gate 		 * guard for this case.  No bytes should be transmitted to
717c478bd9Sstevel@tonic-gate 		 * the buffer when n==0, so using tmpbuf instead of string
727c478bd9Sstevel@tonic-gate 		 * (ie, if string is not NULL) should not matter.
737c478bd9Sstevel@tonic-gate 		 */
747c478bd9Sstevel@tonic-gate 		siop._base = siop._ptr = tmpbuf;
757c478bd9Sstevel@tonic-gate 		siop._cnt = 0;
767c478bd9Sstevel@tonic-gate 	} else if (n > max) {
777c478bd9Sstevel@tonic-gate 		errno = EOVERFLOW;
787c478bd9Sstevel@tonic-gate 		return (EOF);
797c478bd9Sstevel@tonic-gate 	}
817c478bd9Sstevel@tonic-gate 	va_start(ap, format);
827c478bd9Sstevel@tonic-gate 	count = _ndoprnt(format, ap, &siop, 0);
837c478bd9Sstevel@tonic-gate 	va_end(ap);
857c478bd9Sstevel@tonic-gate 	*siop._ptr = '\0';   /* plant terminating null character */
877c478bd9Sstevel@tonic-gate 	if (count == EOF)
887c478bd9Sstevel@tonic-gate 		return (EOF);
907c478bd9Sstevel@tonic-gate 	/* overflow check */
917c478bd9Sstevel@tonic-gate 	if ((size_t)count > max) {
927c478bd9Sstevel@tonic-gate 		errno = EOVERFLOW;
937c478bd9Sstevel@tonic-gate 		return (EOF);
947c478bd9Sstevel@tonic-gate 	} else {
957c478bd9Sstevel@tonic-gate 		return ((int)count);
967c478bd9Sstevel@tonic-gate 	}
977c478bd9Sstevel@tonic-gate }
997c478bd9Sstevel@tonic-gate #ifndef _LP64
1017c478bd9Sstevel@tonic-gate /*
1027c478bd9Sstevel@tonic-gate  * 32-bit shadow function of snprintf().
1037c478bd9Sstevel@tonic-gate  * When using the c89 compiler to build 32-bit applications, the size
1047c478bd9Sstevel@tonic-gate  * of intmax_t is 32-bits, otherwise the size of intmax_t is 64-bits.
1057c478bd9Sstevel@tonic-gate  * The shadow function uses 32-bit size of intmax_t for %j conversion.
1067c478bd9Sstevel@tonic-gate  * The #pragma redefine_extname in <stdio.h> selects the proper routine
1077c478bd9Sstevel@tonic-gate  * at compile time for the user application.
1087c478bd9Sstevel@tonic-gate  * NOTE: this function is only available in the 32-bit library.
1097c478bd9Sstevel@tonic-gate  */
1117c478bd9Sstevel@tonic-gate int
_snprintf_c89(char * string,size_t n,const char * format,...)1127c478bd9Sstevel@tonic-gate _snprintf_c89(char *string, size_t n, const char *format, ...)
1137c478bd9Sstevel@tonic-gate {
1147c478bd9Sstevel@tonic-gate 	ssize_t count;
1157c478bd9Sstevel@tonic-gate 	va_list ap;
1177c478bd9Sstevel@tonic-gate 	va_start(ap, format);
1187c478bd9Sstevel@tonic-gate 	count = _vsnprintf_c89(string, n, format, ap);
1197c478bd9Sstevel@tonic-gate 	va_end(ap);
1207c478bd9Sstevel@tonic-gate 	return ((int)count);
1217c478bd9Sstevel@tonic-gate }
1237c478bd9Sstevel@tonic-gate #endif	/* _LP64 */