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df.c revision 1.21.2.1
      1  1.21.2.1      jtc /*	$NetBSD: df.c,v 1.21.2.1 1995/11/01 00:06:11 jtc Exp $	*/
      2      1.19      cgd 
      3      1.12      cgd /*
      4      1.15  mycroft  * Copyright (c) 1980, 1990, 1993, 1994
      5      1.15  mycroft  *	The Regents of the University of California.  All rights reserved.
      6      1.12      cgd  * (c) UNIX System Laboratories, Inc.
      7      1.12      cgd  * All or some portions of this file are derived from material licensed
      8      1.12      cgd  * to the University of California by American Telephone and Telegraph
      9      1.12      cgd  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     10      1.12      cgd  * the permission of UNIX System Laboratories, Inc.
     11      1.12      cgd  *
     12      1.12      cgd  * Redistribution and use in source and binary forms, with or without
     13      1.12      cgd  * modification, are permitted provided that the following conditions
     14      1.12      cgd  * are met:
     15      1.12      cgd  * 1. Redistributions of source code must retain the above copyright
     16      1.12      cgd  *    notice, this list of conditions and the following disclaimer.
     17      1.12      cgd  * 2. Redistributions in binary form must reproduce the above copyright
     18      1.12      cgd  *    notice, this list of conditions and the following disclaimer in the
     19      1.12      cgd  *    documentation and/or other materials provided with the distribution.
     20      1.12      cgd  * 3. All advertising materials mentioning features or use of this software
     21      1.12      cgd  *    must display the following acknowledgement:
     22      1.12      cgd  *	This product includes software developed by the University of
     23      1.12      cgd  *	California, Berkeley and its contributors.
     24      1.12      cgd  * 4. Neither the name of the University nor the names of its contributors
     25      1.12      cgd  *    may be used to endorse or promote products derived from this software
     26      1.12      cgd  *    without specific prior written permission.
     27      1.12      cgd  *
     28      1.12      cgd  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29      1.12      cgd  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30      1.12      cgd  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31      1.12      cgd  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32      1.12      cgd  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33      1.12      cgd  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34      1.12      cgd  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35      1.12      cgd  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36      1.12      cgd  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37      1.12      cgd  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38      1.12      cgd  * SUCH DAMAGE.
     39      1.12      cgd  */
     40      1.12      cgd 
     41      1.12      cgd #ifndef lint
     42      1.15  mycroft static char copyright[] =
     43      1.15  mycroft "@(#) Copyright (c) 1980, 1990, 1993, 1994\n\
     44      1.15  mycroft 	The Regents of the University of California.  All rights reserved.\n";
     45      1.12      cgd #endif /* not lint */
     46      1.12      cgd 
     47      1.12      cgd #ifndef lint
     48      1.19      cgd #if 0
     49      1.19      cgd static char sccsid[] = "@(#)df.c	8.7 (Berkeley) 4/2/94";
     50      1.19      cgd #else
     51  1.21.2.1      jtc static char rcsid[] = "$NetBSD: df.c,v 1.21.2.1 1995/11/01 00:06:11 jtc Exp $";
     52      1.19      cgd #endif
     53      1.12      cgd #endif /* not lint */
     54      1.12      cgd 
     55      1.12      cgd #include <sys/param.h>
     56      1.12      cgd #include <sys/stat.h>
     57      1.12      cgd #include <sys/mount.h>
     58      1.15  mycroft 
     59      1.15  mycroft #include <err.h>
     60      1.12      cgd #include <errno.h>
     61      1.12      cgd #include <fcntl.h>
     62      1.12      cgd #include <stdio.h>
     63      1.12      cgd #include <stdlib.h>
     64      1.12      cgd #include <string.h>
     65      1.12      cgd #include <unistd.h>
     66      1.12      cgd 
     67      1.15  mycroft int	 bread __P((off_t, void *, int));
     68      1.12      cgd char	*getmntpt __P((char *));
     69      1.15  mycroft void	 prtstat __P((struct statfs *, int));
     70      1.17  mycroft int	 ufs_df __P((char *, struct statfs *));
     71      1.17  mycroft int	 selected __P((const char *));
     72      1.17  mycroft void	 maketypelist __P((char *));
     73      1.17  mycroft long	 regetmntinfo __P((struct statfs **, long));
     74      1.12      cgd void	 usage __P((void));
     75      1.12      cgd 
     76      1.17  mycroft int	iflag, kflag, lflag, nflag;
     77      1.17  mycroft char	**typelist = NULL;
     78      1.12      cgd struct	ufs_args mdev;
     79      1.12      cgd 
     80      1.12      cgd int
     81      1.12      cgd main(argc, argv)
     82      1.12      cgd 	int argc;
     83      1.12      cgd 	char *argv[];
     84      1.12      cgd {
     85      1.12      cgd 	struct stat stbuf;
     86      1.21      jtc 	struct statfs *mntbuf;
     87      1.17  mycroft 	long mntsize;
     88      1.17  mycroft 	int ch, i, maxwidth, width;
     89      1.12      cgd 	char *mntpt;
     90      1.12      cgd 
     91      1.16  mycroft 	while ((ch = getopt(argc, argv, "iklnt:")) != -1)
     92      1.15  mycroft 		switch (ch) {
     93      1.12      cgd 		case 'i':
     94      1.12      cgd 			iflag = 1;
     95      1.12      cgd 			break;
     96      1.12      cgd 		case 'k':
     97      1.12      cgd 			kflag = 1;
     98      1.12      cgd 			break;
     99      1.12      cgd 		case 'l':
    100      1.17  mycroft 			lflag = 1;
    101      1.12      cgd 			break;
    102      1.12      cgd 		case 'n':
    103      1.12      cgd 			nflag = 1;
    104      1.12      cgd 			break;
    105      1.16  mycroft 		case 't':
    106      1.17  mycroft 			if (typelist != NULL)
    107      1.17  mycroft 				errx(1, "only one -t option may be specified.");
    108      1.17  mycroft 			maketypelist(optarg);
    109      1.16  mycroft 			break;
    110      1.12      cgd 		case '?':
    111      1.12      cgd 		default:
    112      1.12      cgd 			usage();
    113      1.12      cgd 		}
    114      1.12      cgd 	argc -= optind;
    115      1.12      cgd 	argv += optind;
    116      1.12      cgd 
    117      1.17  mycroft 	if (*argv && (lflag || typelist != NULL))
    118      1.16  mycroft 		errx(1, "-l or -t does not make sense with list of mount points");
    119      1.12      cgd 
    120      1.17  mycroft 	mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
    121      1.12      cgd 	if (mntsize == 0)
    122      1.14    glass 	        err(1, "retrieving information on mounted file systems");
    123      1.15  mycroft 
    124      1.12      cgd 	if (!*argv) {
    125      1.17  mycroft 		mntsize = regetmntinfo(&mntbuf, mntsize);
    126      1.17  mycroft 	} else {
    127      1.17  mycroft 		mntbuf = malloc(argc * sizeof(struct statfs));
    128      1.17  mycroft 		mntsize = 0;
    129      1.17  mycroft 		for (; *argv; argv++) {
    130      1.17  mycroft 			if (stat(*argv, &stbuf) < 0) {
    131      1.17  mycroft 				if ((mntpt = getmntpt(*argv)) == 0) {
    132      1.17  mycroft 					warn("%s", *argv);
    133      1.12      cgd 					continue;
    134      1.12      cgd 				}
    135      1.18  mycroft 			} else if (S_ISCHR(stbuf.st_mode)) {
    136      1.17  mycroft 				if (!ufs_df(*argv, &mntbuf[mntsize]))
    137      1.17  mycroft 					++mntsize;
    138      1.17  mycroft 				continue;
    139      1.18  mycroft 			} else if (S_ISBLK(stbuf.st_mode)) {
    140      1.17  mycroft 				if ((mntpt = getmntpt(*argv)) == 0) {
    141      1.17  mycroft 					mntpt = mktemp(strdup("/tmp/df.XXXXXX"));
    142      1.17  mycroft 					mdev.fspec = *argv;
    143      1.17  mycroft 					if (mkdir(mntpt, DEFFILEMODE) != 0) {
    144      1.17  mycroft 						warn("%s", mntpt);
    145      1.17  mycroft 						continue;
    146      1.17  mycroft 					}
    147  1.21.2.1      jtc 					if (mount(MOUNT_FFS, mntpt, MNT_RDONLY,
    148      1.17  mycroft 					    &mdev) != 0) {
    149      1.17  mycroft 						(void)rmdir(mntpt);
    150      1.17  mycroft 						if (!ufs_df(*argv, &mntbuf[mntsize]))
    151      1.17  mycroft 							++mntsize;
    152      1.17  mycroft 						continue;
    153      1.17  mycroft 					} else if (!statfs(mntpt, &mntbuf[mntsize])) {
    154      1.17  mycroft 						mntbuf[mntsize].f_mntonname[0] = '\0';
    155      1.17  mycroft 						++mntsize;
    156      1.17  mycroft 					} else
    157      1.17  mycroft 						warn("%s", *argv);
    158      1.17  mycroft 					(void)unmount(mntpt, 0);
    159      1.12      cgd 					(void)rmdir(mntpt);
    160      1.12      cgd 					continue;
    161      1.17  mycroft 				}
    162      1.17  mycroft 			} else
    163      1.17  mycroft 				mntpt = *argv;
    164      1.17  mycroft 			/*
    165      1.17  mycroft 			 * Statfs does not take a `wait' flag, so we cannot
    166      1.17  mycroft 			 * implement nflag here.
    167      1.17  mycroft 			 */
    168      1.17  mycroft 			if (!statfs(mntpt, &mntbuf[mntsize]))
    169      1.17  mycroft 				++mntsize;
    170      1.17  mycroft 			else
    171      1.17  mycroft 				warn("%s", *argv);
    172      1.12      cgd 		}
    173      1.12      cgd 	}
    174      1.17  mycroft 
    175      1.17  mycroft 	maxwidth = 0;
    176      1.17  mycroft 	for (i = 0; i < mntsize; i++) {
    177      1.17  mycroft 		width = strlen(mntbuf[i].f_mntfromname);
    178      1.17  mycroft 		if (width > maxwidth)
    179      1.17  mycroft 			maxwidth = width;
    180      1.17  mycroft 	}
    181      1.17  mycroft 	for (i = 0; i < mntsize; i++)
    182      1.17  mycroft 		prtstat(&mntbuf[i], maxwidth);
    183      1.17  mycroft 	exit(0);
    184      1.12      cgd }
    185      1.12      cgd 
    186      1.12      cgd char *
    187      1.12      cgd getmntpt(name)
    188      1.12      cgd 	char *name;
    189      1.12      cgd {
    190      1.17  mycroft 	long mntsize, i;
    191      1.17  mycroft 	struct statfs *mntbuf;
    192      1.12      cgd 
    193      1.17  mycroft 	mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
    194      1.12      cgd 	for (i = 0; i < mntsize; i++) {
    195      1.12      cgd 		if (!strcmp(mntbuf[i].f_mntfromname, name))
    196      1.12      cgd 			return (mntbuf[i].f_mntonname);
    197      1.12      cgd 	}
    198      1.12      cgd 	return (0);
    199      1.12      cgd }
    200      1.12      cgd 
    201      1.17  mycroft static enum { IN_LIST, NOT_IN_LIST } which;
    202      1.17  mycroft 
    203      1.17  mycroft int
    204      1.17  mycroft selected(type)
    205      1.17  mycroft 	const char *type;
    206      1.17  mycroft {
    207      1.17  mycroft 	char **av;
    208      1.17  mycroft 
    209      1.17  mycroft 	/* If no type specified, it's always selected. */
    210      1.17  mycroft 	if (typelist == NULL)
    211      1.17  mycroft 		return (1);
    212      1.17  mycroft 	for (av = typelist; *av != NULL; ++av)
    213      1.20      cgd 		if (!strncmp(type, *av, MFSNAMELEN))
    214      1.17  mycroft 			return (which == IN_LIST ? 1 : 0);
    215      1.17  mycroft 	return (which == IN_LIST ? 0 : 1);
    216      1.17  mycroft }
    217      1.16  mycroft 
    218      1.16  mycroft void
    219      1.17  mycroft maketypelist(fslist)
    220      1.17  mycroft 	char *fslist;
    221      1.16  mycroft {
    222      1.17  mycroft 	int i;
    223      1.17  mycroft 	char *nextcp, **av;
    224      1.16  mycroft 
    225      1.17  mycroft 	if ((fslist == NULL) || (fslist[0] == '\0'))
    226      1.17  mycroft 		errx(1, "empty type list");
    227      1.16  mycroft 
    228      1.17  mycroft 	/*
    229      1.17  mycroft 	 * XXX
    230      1.17  mycroft 	 * Note: the syntax is "noxxx,yyy" for no xxx's and
    231      1.17  mycroft 	 * no yyy's, not the more intuitive "noyyy,noyyy".
    232      1.17  mycroft 	 */
    233      1.17  mycroft 	if (fslist[0] == 'n' && fslist[1] == 'o') {
    234      1.17  mycroft 		fslist += 2;
    235      1.17  mycroft 		which = NOT_IN_LIST;
    236      1.17  mycroft 	} else
    237      1.17  mycroft 		which = IN_LIST;
    238      1.17  mycroft 
    239      1.17  mycroft 	/* Count the number of types. */
    240      1.17  mycroft 	for (i = 1, nextcp = fslist; nextcp = strchr(nextcp, ','); i++)
    241      1.17  mycroft 		++nextcp;
    242      1.17  mycroft 
    243      1.17  mycroft 	/* Build an array of that many types. */
    244      1.17  mycroft 	if ((av = typelist = malloc((i + 1) * sizeof(char *))) == NULL)
    245      1.17  mycroft 		err(1, NULL);
    246      1.17  mycroft 	av[0] = fslist;
    247      1.17  mycroft 	for (i = 1, nextcp = fslist; nextcp = strchr(nextcp, ','); i++) {
    248      1.17  mycroft 		*nextcp = '\0';
    249      1.17  mycroft 		av[i] = ++nextcp;
    250      1.16  mycroft 	}
    251      1.17  mycroft 	/* Terminate the array. */
    252      1.17  mycroft 	av[i] = NULL;
    253      1.17  mycroft }
    254      1.16  mycroft 
    255      1.17  mycroft /*
    256      1.17  mycroft  * Make a pass over the filesystem info in ``mntbuf'' filtering out
    257      1.17  mycroft  * filesystem types not in ``fsmask'' and possibly re-stating to get
    258      1.17  mycroft  * current (not cached) info.  Returns the new count of valid statfs bufs.
    259      1.17  mycroft  */
    260      1.17  mycroft long
    261      1.17  mycroft regetmntinfo(mntbufp, mntsize)
    262      1.17  mycroft 	struct statfs **mntbufp;
    263      1.17  mycroft 	long mntsize;
    264      1.17  mycroft {
    265      1.17  mycroft 	int i, j;
    266      1.17  mycroft 	struct statfs *mntbuf;
    267      1.16  mycroft 
    268      1.17  mycroft 	if (!lflag && typelist == NULL)
    269      1.17  mycroft 		return (nflag ? mntsize : getmntinfo(mntbufp, MNT_WAIT));
    270      1.16  mycroft 
    271      1.17  mycroft 	mntbuf = *mntbufp;
    272      1.17  mycroft 	j = 0;
    273      1.17  mycroft 	for (i = 0; i < mntsize; i++) {
    274      1.17  mycroft 		if (lflag && (mntbuf[i].f_flags & MNT_LOCAL) == 0)
    275      1.17  mycroft 			continue;
    276      1.17  mycroft 		if (!selected(mntbuf[i].f_fstypename))
    277      1.17  mycroft 			continue;
    278      1.17  mycroft 		if (nflag)
    279      1.17  mycroft 			mntbuf[j] = mntbuf[i];
    280      1.17  mycroft 		else
    281      1.17  mycroft 			(void)statfs(mntbuf[i].f_mntonname, &mntbuf[j]);
    282      1.17  mycroft 		j++;
    283      1.16  mycroft 	}
    284      1.17  mycroft 	return (j);
    285      1.16  mycroft }
    286      1.16  mycroft 
    287      1.12      cgd /*
    288      1.15  mycroft  * Convert statfs returned filesystem size into BLOCKSIZE units.
    289      1.15  mycroft  * Attempts to avoid overflow for large filesystems.
    290      1.15  mycroft  */
    291      1.15  mycroft #define fsbtoblk(num, fsbs, bs) \
    292      1.15  mycroft 	(((fsbs) != 0 && (fsbs) < (bs)) ? \
    293      1.15  mycroft 		(num) / ((bs) / (fsbs)) : (num) * ((fsbs) / (bs)))
    294      1.15  mycroft 
    295      1.15  mycroft /*
    296      1.12      cgd  * Print out status about a filesystem.
    297      1.12      cgd  */
    298      1.12      cgd void
    299      1.12      cgd prtstat(sfsp, maxwidth)
    300      1.15  mycroft 	struct statfs *sfsp;
    301      1.15  mycroft 	int maxwidth;
    302      1.12      cgd {
    303      1.17  mycroft 	static long blocksize;
    304      1.12      cgd 	static int headerlen, timesthrough;
    305      1.12      cgd 	static char *header;
    306      1.12      cgd 	long used, availblks, inodes;
    307      1.12      cgd 
    308      1.12      cgd 	if (maxwidth < 11)
    309      1.12      cgd 		maxwidth = 11;
    310      1.12      cgd 	if (++timesthrough == 1) {
    311      1.12      cgd 		if (kflag) {
    312      1.17  mycroft 			blocksize = 1024;
    313      1.12      cgd 			header = "1K-blocks";
    314      1.12      cgd 			headerlen = strlen(header);
    315      1.12      cgd 		} else
    316      1.12      cgd 			header = getbsize(&headerlen, &blocksize);
    317      1.15  mycroft 		(void)printf("%-*.*s %s     Used    Avail Capacity",
    318      1.12      cgd 		    maxwidth, maxwidth, "Filesystem", header);
    319      1.12      cgd 		if (iflag)
    320      1.12      cgd 			(void)printf(" iused   ifree  %%iused");
    321      1.12      cgd 		(void)printf("  Mounted on\n");
    322      1.12      cgd 	}
    323      1.12      cgd 	(void)printf("%-*.*s", maxwidth, maxwidth, sfsp->f_mntfromname);
    324      1.12      cgd 	used = sfsp->f_blocks - sfsp->f_bfree;
    325      1.12      cgd 	availblks = sfsp->f_bavail + used;
    326      1.15  mycroft 	(void)printf(" %*ld %8ld %8ld", headerlen,
    327      1.15  mycroft 	    fsbtoblk(sfsp->f_blocks, sfsp->f_bsize, blocksize),
    328      1.15  mycroft 	    fsbtoblk(used, sfsp->f_bsize, blocksize),
    329      1.15  mycroft 	    fsbtoblk(sfsp->f_bavail, sfsp->f_bsize, blocksize));
    330      1.12      cgd 	(void)printf(" %5.0f%%",
    331      1.12      cgd 	    availblks == 0 ? 100.0 : (double)used / (double)availblks * 100.0);
    332      1.12      cgd 	if (iflag) {
    333      1.12      cgd 		inodes = sfsp->f_files;
    334      1.12      cgd 		used = inodes - sfsp->f_ffree;
    335      1.12      cgd 		(void)printf(" %7ld %7ld %5.0f%% ", used, sfsp->f_ffree,
    336      1.12      cgd 		   inodes == 0 ? 100.0 : (double)used / (double)inodes * 100.0);
    337      1.12      cgd 	} else
    338      1.12      cgd 		(void)printf("  ");
    339      1.12      cgd 	(void)printf("  %s\n", sfsp->f_mntonname);
    340      1.12      cgd }
    341      1.12      cgd 
    342      1.12      cgd /*
    343      1.15  mycroft  * This code constitutes the pre-system call Berkeley df code for extracting
    344      1.12      cgd  * information from filesystem superblocks.
    345      1.12      cgd  */
    346      1.13   chopps #include <ufs/ffs/fs.h>
    347      1.12      cgd #include <errno.h>
    348      1.12      cgd #include <fstab.h>
    349      1.12      cgd 
    350      1.12      cgd union {
    351      1.12      cgd 	struct fs iu_fs;
    352      1.12      cgd 	char dummy[SBSIZE];
    353      1.12      cgd } sb;
    354      1.12      cgd #define sblock sb.iu_fs
    355      1.12      cgd 
    356      1.15  mycroft int	rfd;
    357      1.12      cgd 
    358      1.17  mycroft int
    359      1.17  mycroft ufs_df(file, sfsp)
    360      1.12      cgd 	char *file;
    361      1.17  mycroft 	struct statfs *sfsp;
    362      1.12      cgd {
    363      1.12      cgd 	char *mntpt;
    364      1.12      cgd 	static int synced;
    365      1.12      cgd 
    366      1.12      cgd 	if (synced++ == 0)
    367      1.12      cgd 		sync();
    368      1.12      cgd 
    369      1.15  mycroft 	if ((rfd = open(file, O_RDONLY)) < 0) {
    370      1.12      cgd 		warn("%s", file);
    371      1.17  mycroft 		return (-1);
    372      1.12      cgd 	}
    373      1.15  mycroft 	if (bread((off_t)SBOFF, &sblock, SBSIZE) == 0) {
    374      1.15  mycroft 		(void)close(rfd);
    375      1.17  mycroft 		return (-1);
    376      1.12      cgd 	}
    377      1.12      cgd 	sfsp->f_type = 0;
    378      1.12      cgd 	sfsp->f_flags = 0;
    379      1.15  mycroft 	sfsp->f_bsize = sblock.fs_fsize;
    380      1.12      cgd 	sfsp->f_iosize = sblock.fs_bsize;
    381      1.12      cgd 	sfsp->f_blocks = sblock.fs_dsize;
    382      1.12      cgd 	sfsp->f_bfree = sblock.fs_cstotal.cs_nbfree * sblock.fs_frag +
    383      1.12      cgd 		sblock.fs_cstotal.cs_nffree;
    384      1.12      cgd 	sfsp->f_bavail = (sblock.fs_dsize * (100 - sblock.fs_minfree) / 100) -
    385      1.12      cgd 		(sblock.fs_dsize - sfsp->f_bfree);
    386      1.12      cgd 	if (sfsp->f_bavail < 0)
    387      1.12      cgd 		sfsp->f_bavail = 0;
    388      1.12      cgd 	sfsp->f_files =  sblock.fs_ncg * sblock.fs_ipg;
    389      1.12      cgd 	sfsp->f_ffree = sblock.fs_cstotal.cs_nifree;
    390      1.12      cgd 	sfsp->f_fsid.val[0] = 0;
    391      1.12      cgd 	sfsp->f_fsid.val[1] = 0;
    392      1.12      cgd 	if ((mntpt = getmntpt(file)) == 0)
    393      1.12      cgd 		mntpt = "";
    394      1.15  mycroft 	memmove(&sfsp->f_mntonname[0], mntpt, MNAMELEN);
    395      1.15  mycroft 	memmove(&sfsp->f_mntfromname[0], file, MNAMELEN);
    396  1.21.2.1      jtc 	strncpy(sfsp->f_fstypename, MOUNT_FFS, MFSNAMELEN);
    397      1.15  mycroft 	(void)close(rfd);
    398      1.17  mycroft 	return (0);
    399      1.12      cgd }
    400      1.12      cgd 
    401      1.12      cgd int
    402      1.12      cgd bread(off, buf, cnt)
    403      1.15  mycroft 	off_t off;
    404      1.15  mycroft 	void *buf;
    405      1.12      cgd 	int cnt;
    406      1.12      cgd {
    407      1.15  mycroft 	int nr;
    408      1.12      cgd 
    409      1.15  mycroft 	(void)lseek(rfd, off, SEEK_SET);
    410      1.15  mycroft 	if ((nr = read(rfd, buf, cnt)) != cnt) {
    411      1.15  mycroft 		/* Probably a dismounted disk if errno == EIO. */
    412      1.15  mycroft 		if (errno != EIO)
    413      1.15  mycroft 			(void)fprintf(stderr, "\ndf: %qd: %s\n",
    414      1.15  mycroft 			    off, strerror(nr > 0 ? EIO : errno));
    415      1.12      cgd 		return (0);
    416      1.12      cgd 	}
    417      1.12      cgd 	return (1);
    418      1.12      cgd }
    419      1.12      cgd 
    420      1.12      cgd void
    421      1.12      cgd usage()
    422      1.12      cgd {
    423      1.16  mycroft 	(void)fprintf(stderr, "usage: df [-ikln] [-t type] [file | file_system ...]\n");
    424      1.12      cgd 	exit(1);
    425      1.12      cgd }
    426