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. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * $FreeBSD: src/usr.bin/fstat/msdosfs.c,v 1.1.2.2 2001/11/21 10:49:37 dwmalone Exp $
  33  */
  34
  35 #define _KERNEL_STRUCTURES
  36
  37 #include <sys/param.h>
  38 #include <sys/time.h>
  39 #include <sys/stat.h>
  40 #include <sys/vnode.h>
  41
  42 #include <sys/mount.h>
  43 #include <vfs/msdosfs/bpb.h>
  44 #include <vfs/msdosfs/msdosfsmount.h>
  45
  46 #include <vfs/msdosfs/denode.h>
  47 #include <vfs/msdosfs/direntry.h>
  48 #include <vfs/msdosfs/fat.h>
  49
  50 #include <err.h>
  51 #include <kvm.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54
  55 /*
  56  * XXX -
  57  * VTODE is defined in denode.h only if _KERNEL is defined, but that leads to
  58  * header explosion
  59  */
  60 #define VTODE(vp) ((struct denode *)(vp)->v_data)
  61
  62 #include "fstat.h"
  63
  64 struct dosmount {
  65         struct dosmount *next;
  66         struct msdosfsmount *kptr;      /* Pointer in kernel space */
  67         struct msdosfsmount data;       /* User space copy of structure */
  68 };
  69
  70 int
  71 msdosfs_filestat(struct vnode *vp, struct filestat *fsp)
  72 {
  73         struct denode denode;
  74         static struct dosmount *mounts;
  75         struct dosmount *mnt;
  76         u_long dirsperblk;
  77         int fileid;
  78
  79         if (!kread(VTODE(vp), &denode, sizeof (denode))) {
  80                 dprintf(stderr, "can't read denode at %p for pid %d\n",
  81                     (void *)VTODE(vp), Pid);
  82                 return 0;
  83         }
  84
  85         /*
  86          * Find msdosfsmount structure for the vnode's filesystem. Needed
  87          * for some filesystem parameters
  88          */
  89         for (mnt = mounts; mnt; mnt = mnt->next)
  90                 if (mnt->kptr == denode.de_pmp)
  91                         break;
  92
  93         if (!mnt) {
  94                 if ((mnt = malloc(sizeof(struct dosmount))) == NULL)
  95                         err(1, NULL);
  96                 mnt->next = mounts;
  97                 mounts = mnt;
  98                 mnt->kptr = denode.de_pmp;
  99                 if (!kread(denode.de_pmp, &mnt->data, sizeof mnt->data)) {
 100                         dprintf(stderr,
 101                             "can't read mount info at %p for pid %d\n",
 102                             (void *)denode.de_pmp, Pid);
 103                         return 0;
 104                 }
 105         }
 106
 107         fsp->fsid = fsp->rdev = fstat_dev2udev(denode.de_dev);
 108         fsp->mode = 0555;
 109         fsp->mode |= denode.de_Attributes & ATTR_READONLY ? 0 : 0222;
 110         fsp->mode &= mnt->data.pm_mask;
 111
 112         /* Distinguish directories and files. No "special" files in FAT. */
 113         fsp->mode |= denode.de_Attributes & ATTR_DIRECTORY ? S_IFDIR : S_IFREG;
 114
 115         fsp->size = denode.de_FileSize;
 116
 117         /*
 118          * XXX -
 119          * Culled from msdosfs_vnops.c. There appears to be a problem
 120          * here, in that a directory has the same inode number as the first
 121          * file in the directory. stat(2) suffers from this problem also, so
 122          * I won't try to fix it here.
 123          *
 124          * The following computation of the fileid must be the same as that
 125          * used in msdosfs_readdir() to compute d_fileno. If not, pwd
 126          * doesn't work.
 127          */
 128         dirsperblk = mnt->data.pm_BytesPerSec / sizeof(struct direntry);
 129         if (denode.de_Attributes & ATTR_DIRECTORY) {
 130                 fileid = cntobn(&mnt->data, denode.de_StartCluster)
 131                     * dirsperblk;
 132                 if (denode.de_StartCluster == MSDOSFSROOT)
 133                         fileid = 1;
 134         } else {
 135                 fileid = cntobn(&mnt->data, denode.de_dirclust) * dirsperblk;
 136                 if (denode.de_dirclust == MSDOSFSROOT)
 137                         fileid = roottobn(&mnt->data, 0) * dirsperblk;
 138                 fileid += denode.de_diroffset / sizeof(struct direntry);
 139         }
 140
 141         fsp->fileid = fileid;
 142         return 1;
 143 }