usr.bin/fstat/msdosfs.c

   1 /*
   2  * Copyright (c) 2000 Peter Edwards
   3  * Copyright (c) 1988, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by Peter Edwards
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD$");
  39
  40 #include <sys/param.h>
  41 #include <sys/time.h>
  42 #include <sys/stat.h>
  43 #include <sys/vnode.h>
  44
  45 #define _KERNEL
  46 #include <sys/mount.h>
  47 #include <fs/msdosfs/bpb.h>
  48 #include <fs/msdosfs/msdosfsmount.h>
  49 #undef _KERNEL
  50
  51 #include <fs/msdosfs/denode.h>
  52 #include <fs/msdosfs/direntry.h>
  53 #include <fs/msdosfs/fat.h>
  54
  55 #include <err.h>
  56 #include <kvm.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59
  60 /*
  61  * XXX -
  62  * VTODE is defined in denode.h only if _KERNEL is defined, but that leads to
  63  * header explosion
  64  */
  65 #define VTODE(vp) ((struct denode *)(vp)->v_data)
  66
  67 #include "fstat.h"
  68
  69 struct dosmount {
  70         struct dosmount *next;
  71         struct msdosfsmount *kptr;      /* Pointer in kernel space */
  72         struct msdosfsmount data;       /* User space copy of structure */
  73 };
  74
  75 int
  76 msdosfs_filestat(struct vnode *vp, struct filestat *fsp)
  77 {
  78         struct denode denode;
  79         static struct dosmount *mounts;
  80         struct dosmount *mnt;
  81         u_long dirsperblk;
  82         int fileid;
  83
  84         if (!KVM_READ(VTODE(vp), &denode, sizeof (denode))) {
  85                 dprintf(stderr, "can't read denode at %p for pid %d\n",
  86                     (void *)VTODE(vp), Pid);
  87                 return 0;
  88         }
  89
  90         /*
  91          * Find msdosfsmount structure for the vnode's filesystem. Needed
  92          * for some filesystem parameters
  93          */
  94         for (mnt = mounts; mnt; mnt = mnt->next)
  95                 if (mnt->kptr == denode.de_pmp)
  96                         break;
  97
  98         if (!mnt) {
  99                 if ((mnt = malloc(sizeof(struct dosmount))) == NULL)
 100                         err(1, NULL);
 101                 if (!KVM_READ(denode.de_pmp, &mnt->data, sizeof mnt->data)) {
 102                         free(mnt);
 103                         dprintf(stderr,
 104                             "can't read mount info at %p for pid %d\n",
 105                             (void *)denode.de_pmp, Pid);
 106                         return 0;
 107                 }
 108                 mnt->next = mounts;
 109                 mounts = mnt;
 110                 mnt->kptr = denode.de_pmp;
 111         }
 112
 113         fsp->fsid = dev2udev(denode.de_dev);
 114         fsp->mode = 0555;
 115         fsp->mode |= denode.de_Attributes & ATTR_READONLY ? 0 : 0222;
 116         fsp->mode &= mnt->data.pm_mask;
 117
 118         /* Distinguish directories and files. No "special" files in FAT. */
 119         fsp->mode |= denode.de_Attributes & ATTR_DIRECTORY ? S_IFDIR : S_IFREG;
 120
 121         fsp->size = denode.de_FileSize;
 122         fsp->rdev = 0;
 123
 124         /*
 125          * XXX -
 126          * Culled from msdosfs_vnops.c. There appears to be a problem
 127          * here, in that a directory has the same inode number as the first
 128          * file in the directory. stat(2) suffers from this problem also, so
 129          * I won't try to fix it here.
 130          *
 131          * The following computation of the fileid must be the same as that
 132          * used in msdosfs_readdir() to compute d_fileno. If not, pwd
 133          * doesn't work.
 134          */
 135         dirsperblk = mnt->data.pm_BytesPerSec / sizeof(struct direntry);
 136         if (denode.de_Attributes & ATTR_DIRECTORY) {
 137                 fileid = cntobn(&mnt->data, denode.de_StartCluster)
 138                     * dirsperblk;
 139                 if (denode.de_StartCluster == MSDOSFSROOT)
 140                         fileid = 1;
 141         } else {
 142                 fileid = cntobn(&mnt->data, denode.de_dirclust) * dirsperblk;
 143                 if (denode.de_dirclust == MSDOSFSROOT)
 144                         fileid = roottobn(&mnt->data, 0) * dirsperblk;
 145                 fileid += denode.de_diroffset / sizeof(struct direntry);
 146         }
 147
 148         fsp->fileid = fileid;
 149         return 1;
 150 }