xref: /freebsd/lib/libc/gen/getmntinfo.c (revision 5a28df2e1353d67f22da176402a3e906be39b59b)
158f0484fSRodney W. Grimes /*
258f0484fSRodney W. Grimes  * Copyright (c) 1989, 1993
358f0484fSRodney W. Grimes  *	The Regents of the University of California.  All rights reserved.
458f0484fSRodney W. Grimes  *
558f0484fSRodney W. Grimes  * Redistribution and use in source and binary forms, with or without
658f0484fSRodney W. Grimes  * modification, are permitted provided that the following conditions
758f0484fSRodney W. Grimes  * are met:
858f0484fSRodney W. Grimes  * 1. Redistributions of source code must retain the above copyright
958f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer.
1058f0484fSRodney W. Grimes  * 2. Redistributions in binary form must reproduce the above copyright
1158f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer in the
1258f0484fSRodney W. Grimes  *    documentation and/or other materials provided with the distribution.
13fbbd9655SWarner Losh  * 3. Neither the name of the University nor the names of its contributors
1458f0484fSRodney W. Grimes  *    may be used to endorse or promote products derived from this software
1558f0484fSRodney W. Grimes  *    without specific prior written permission.
1658f0484fSRodney W. Grimes  *
1758f0484fSRodney W. Grimes  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
1858f0484fSRodney W. Grimes  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1958f0484fSRodney W. Grimes  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
2058f0484fSRodney W. Grimes  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
2158f0484fSRodney W. Grimes  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
2258f0484fSRodney W. Grimes  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2358f0484fSRodney W. Grimes  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
2458f0484fSRodney W. Grimes  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
2558f0484fSRodney W. Grimes  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
2658f0484fSRodney W. Grimes  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
2758f0484fSRodney W. Grimes  * SUCH DAMAGE.
2858f0484fSRodney W. Grimes  */
2958f0484fSRodney W. Grimes 
3058f0484fSRodney W. Grimes #if defined(LIBC_SCCS) && !defined(lint)
3158f0484fSRodney W. Grimes static char sccsid[] = "@(#)getmntinfo.c	8.1 (Berkeley) 6/4/93";
3258f0484fSRodney W. Grimes #endif /* LIBC_SCCS and not lint */
33ea8d448aSDavid E. O'Brien #include <sys/cdefs.h>
34ea8d448aSDavid E. O'Brien __FBSDID("$FreeBSD$");
3558f0484fSRodney W. Grimes 
3658f0484fSRodney W. Grimes #include <sys/param.h>
3758f0484fSRodney W. Grimes #include <sys/ucred.h>
3858f0484fSRodney W. Grimes #include <sys/mount.h>
3958f0484fSRodney W. Grimes #include <stdlib.h>
4058f0484fSRodney W. Grimes 
41*5a28df2eSConrad Meyer #define	MAX_TRIES	3
42*5a28df2eSConrad Meyer #define	SCALING_FACTOR	2
43*5a28df2eSConrad Meyer 
4458f0484fSRodney W. Grimes /*
4558f0484fSRodney W. Grimes  * Return information about mounted filesystems.
4658f0484fSRodney W. Grimes  */
4758f0484fSRodney W. Grimes int
4834ed0c63SJohn Baldwin getmntinfo(struct statfs **mntbufp, int mode)
4958f0484fSRodney W. Grimes {
5058f0484fSRodney W. Grimes 	static struct statfs *mntbuf;
5158f0484fSRodney W. Grimes 	static int mntsize;
5258f0484fSRodney W. Grimes 	static long bufsize;
53*5a28df2eSConrad Meyer 	unsigned tries = 0;
5458f0484fSRodney W. Grimes 
5558f0484fSRodney W. Grimes 	if (mntsize <= 0 && (mntsize = getfsstat(0, 0, MNT_NOWAIT)) < 0)
5658f0484fSRodney W. Grimes 		return (0);
5734ed0c63SJohn Baldwin 	if (bufsize > 0 && (mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
5858f0484fSRodney W. Grimes 		return (0);
59*5a28df2eSConrad Meyer 	while (tries++ < MAX_TRIES && bufsize <= mntsize * sizeof(*mntbuf)) {
60*5a28df2eSConrad Meyer 		bufsize = (mntsize * SCALING_FACTOR) * sizeof(*mntbuf);
61*5a28df2eSConrad Meyer 		if ((mntbuf = reallocf(mntbuf, bufsize)) == NULL)
6258f0484fSRodney W. Grimes 			return (0);
6334ed0c63SJohn Baldwin 		if ((mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
6458f0484fSRodney W. Grimes 			return (0);
6558f0484fSRodney W. Grimes 	}
6658f0484fSRodney W. Grimes 	*mntbufp = mntbuf;
67*5a28df2eSConrad Meyer 	if (mntsize > (bufsize / sizeof(*mntbuf)))
68*5a28df2eSConrad Meyer 		return (bufsize / sizeof(*mntbuf));
6958f0484fSRodney W. Grimes 	return (mntsize);
7058f0484fSRodney W. Grimes }
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