760 lines
17 KiB
C
760 lines
17 KiB
C
/* $NetBSD: dosfs.c,v 1.6 2003/07/15 13:27:07 scw Exp $ */
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/*
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* Copyright (c) 1996, 1998 Robert Nordier
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
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* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Readonly filesystem for Microsoft FAT12/FAT16/FAT32 filesystems,
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* also supports VFAT.
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*/
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/*
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* XXX DOES NOT SUPPORT:
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*
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* LIBSA_FS_SINGLECOMPONENT
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*/
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#include <sys/param.h>
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#include <fs/msdosfs/bpb.h>
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#include <fs/msdosfs/direntry.h>
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#ifdef _STANDALONE
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#include <lib/libkern/libkern.h>
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#else
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#include <string.h>
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#include <stddef.h>
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#endif
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#include "stand.h"
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#include "dosfs.h"
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#define SECSIZ 512 /* sector size */
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#define SSHIFT 9 /* SECSIZ shift */
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#define DEPSEC 16 /* directory entries per sector */
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#define DSHIFT 4 /* DEPSEC shift */
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#define LOCLUS 2 /* lowest cluster number */
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typedef union {
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struct direntry de; /* standard directory entry */
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struct winentry xde; /* extended directory entry */
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} DOS_DIR;
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typedef struct {
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struct open_file *fd; /* file descriptor */
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u_char *buf; /* buffer */
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u_int bufsec; /* buffered sector */
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u_int links; /* active links to structure */
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u_int spc; /* sectors per cluster */
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u_int bsize; /* cluster size in bytes */
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u_int bshift; /* cluster conversion shift */
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u_int dirents; /* root directory entries */
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u_int spf; /* sectors per fat */
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u_int rdcl; /* root directory start cluster */
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u_int lsnfat; /* start of fat */
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u_int lsndir; /* start of root dir */
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u_int lsndta; /* start of data area */
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u_int fatsz; /* FAT entry size */
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u_int xclus; /* maximum cluster number */
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} DOS_FS;
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typedef struct {
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DOS_FS *fs; /* associated filesystem */
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struct direntry de; /* directory entry */
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u_int offset; /* current offset */
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u_int c; /* last cluster read */
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} DOS_FILE;
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/* Initial portion of DOS boot sector */
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typedef struct {
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u_char jmp[3]; /* usually 80x86 'jmp' opcode */
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u_char oem[8]; /* OEM name and version */
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struct byte_bpb710 bpb; /* BPB */
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} DOS_BS;
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/* Supply missing "." and ".." root directory entries */
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static const char *const dotstr[2] = {".", ".."};
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static const struct direntry dot[2] = {
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{". ", " ", ATTR_DIRECTORY,
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0, 0, {0, 0}, {0, 0}, {0, 0}, {0, 0},
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{0, 0}, {0x21, 0}, {0, 0}, {0, 0, 0, 0}},
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{".. ", " ", ATTR_DIRECTORY,
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0, 0, {0, 0}, {0, 0}, {0, 0}, {0, 0},
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{0, 0}, {0x21, 0}, {0, 0}, {0, 0, 0, 0}}
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};
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/* The usual conversion macros to avoid multiplication and division */
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#define bytsec(n) ((n) >> SSHIFT)
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#define secbyt(s) ((s) << SSHIFT)
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#define entsec(e) ((e) >> DSHIFT)
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#define bytblk(fs, n) ((n) >> (fs)->bshift)
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#define blkbyt(fs, b) ((b) << (fs)->bshift)
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#define secblk(fs, s) ((s) >> ((fs)->bshift - SSHIFT))
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#define blksec(fs, b) ((b) << ((fs)->bshift - SSHIFT))
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/* Convert cluster number to offset within filesystem */
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#define blkoff(fs, b) (secbyt((fs)->lsndta) + blkbyt(fs, (b) - LOCLUS))
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/* Convert cluster number to logical sector number */
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#define blklsn(fs, b) ((fs)->lsndta + blksec(fs, (b) - LOCLUS))
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/* Convert cluster number to offset within FAT */
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#define fatoff(sz, c) ((sz) == 12 ? (c) + ((c) >> 1) : \
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(sz) == 16 ? (c) << 1 : \
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(c) << 2)
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/* Does cluster number reference a valid data cluster? */
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#define okclus(fs, c) ((c) >= LOCLUS && (c) <= (fs)->xclus)
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/* Get start cluster from directory entry */
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#define stclus(sz, de) ((sz) != 32 ? getushort((de)->deStartCluster) : \
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((u_int)getushort((de)->deHighClust) << 16) | \
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getushort((de)->deStartCluster))
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static int dosunmount(DOS_FS *);
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static int parsebs(DOS_FS *, DOS_BS *);
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static int namede(DOS_FS *, const char *, const struct direntry **);
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static int lookup(DOS_FS *, u_int, const char *, const struct direntry **);
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static void cp_xdnm(u_char *, struct winentry *);
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static void cp_sfn(u_char *, struct direntry *);
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static off_t fsize(DOS_FS *, struct direntry *);
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static int fatcnt(DOS_FS *, u_int);
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static int fatget(DOS_FS *, u_int *);
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static int fatend(u_int, u_int);
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static int ioread(DOS_FS *, u_int, void *, u_int);
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static int iobuf(DOS_FS *, u_int);
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static int ioget(struct open_file *, u_int, void *, u_int);
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/*
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* Mount DOS filesystem
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*/
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static int
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dos_mount(DOS_FS * fs, struct open_file * fd)
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{
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int err;
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bzero(fs, sizeof(DOS_FS));
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fs->fd = fd;
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if ((err = !(fs->buf = alloc(SECSIZ)) ? errno : 0) ||
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(err = ioget(fs->fd, 0, fs->buf, 1)) ||
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(err = parsebs(fs, (DOS_BS *) fs->buf))) {
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(void) dosunmount(fs);
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return (err);
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}
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return 0;
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}
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#ifndef LIBSA_NO_FS_CLOSE
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/*
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* Unmount mounted filesystem
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*/
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static int
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dos_unmount(DOS_FS * fs)
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{
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int err;
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if (fs->links)
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return (EBUSY);
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if ((err = dosunmount(fs)))
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return (err);
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return 0;
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}
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#endif
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/*
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* Common code shared by dos_mount() and dos_unmount()
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*/
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static int
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dosunmount(DOS_FS * fs)
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{
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if (fs->buf)
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free(fs->buf, SECSIZ);
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free(fs, sizeof(DOS_FS));
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return (0);
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}
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/*
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* Open DOS file
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*/
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int
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dosfs_open(char *path, struct open_file *fd)
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{
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const struct direntry *de;
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DOS_FILE *f;
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DOS_FS *fs;
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u_int size, clus;
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int err = 0;
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/* Allocate mount structure, associate with open */
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fs = alloc(sizeof(DOS_FS));
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if ((err = dos_mount(fs, fd)))
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goto out;
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if ((err = namede(fs, path, &de)))
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goto out;
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clus = stclus(fs->fatsz, de);
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size = getulong(de->deFileSize);
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if ((!(de->deAttributes & ATTR_DIRECTORY) && (!clus != !size)) ||
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((de->deAttributes & ATTR_DIRECTORY) && size) ||
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(clus && !okclus(fs, clus))) {
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err = EINVAL;
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goto out;
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}
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f = alloc(sizeof(DOS_FILE));
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bzero(f, sizeof(DOS_FILE));
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f->fs = fs;
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fs->links++;
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f->de = *de;
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fd->f_fsdata = (void *) f;
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out:
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return (err);
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}
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/*
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* Read from file
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*/
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int
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dosfs_read(struct open_file * fd, void *vbuf, size_t nbyte, size_t * resid)
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{
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off_t size;
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u_int8_t *buf = vbuf;
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u_int nb, off, clus, c, cnt, n;
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DOS_FILE *f = (DOS_FILE *) fd->f_fsdata;
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int err = 0;
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nb = (u_int) nbyte;
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if ((size = fsize(f->fs, &f->de)) == -1)
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return EINVAL;
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if (nb > (n = size - f->offset))
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nb = n;
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off = f->offset;
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if ((clus = stclus(f->fs->fatsz, &f->de)))
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off &= f->fs->bsize - 1;
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c = f->c;
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cnt = nb;
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while (cnt) {
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n = 0;
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if (!c) {
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if ((c = clus))
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n = bytblk(f->fs, f->offset);
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} else if (!off)
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n++;
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while (n--) {
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if ((err = fatget(f->fs, &c)))
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goto out;
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if (!okclus(f->fs, c)) {
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err = EINVAL;
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goto out;
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}
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}
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if (!clus || (n = f->fs->bsize - off) > cnt)
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n = cnt;
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if ((err = ioread(f->fs, (c ? blkoff(f->fs, c) :
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secbyt(f->fs->lsndir)) + off,
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buf, n)))
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goto out;
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f->offset += n;
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f->c = c;
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off = 0;
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buf += n;
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cnt -= n;
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}
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out:
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if (resid)
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*resid = nbyte - nb + cnt;
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return (err);
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}
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#ifndef LIBSA_NO_FS_WRITE
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/*
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* Not implemented.
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*/
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int
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dosfs_write(struct open_file *fd, void *start, size_t size, size_t *resid)
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{
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return (EROFS);
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}
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#endif /* !LIBSA_NO_FS_WRITE */
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#ifndef LIBSA_NO_FS_SEEK
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/*
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* Reposition within file
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*/
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off_t
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dosfs_seek(struct open_file * fd, off_t offset, int whence)
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{
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off_t off;
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u_int size;
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DOS_FILE *f = (DOS_FILE *) fd->f_fsdata;
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size = getulong(f->de.deFileSize);
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switch (whence) {
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case SEEK_SET:
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off = 0;
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break;
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case SEEK_CUR:
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off = f->offset;
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break;
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case SEEK_END:
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off = size;
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break;
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default:
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return (-1);
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}
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off += offset;
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if (off < 0 || off > size)
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return (-1);
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f->offset = (u_int) off;
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f->c = 0;
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return (off);
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}
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#endif /* !LIBSA_NO_FS_SEEK */
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#ifndef LIBSA_NO_FS_CLOSE
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/*
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* Close open file
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*/
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int
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dosfs_close(struct open_file * fd)
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{
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DOS_FILE *f = (DOS_FILE *) fd->f_fsdata;
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DOS_FS *fs = f->fs;
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f->fs->links--;
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free(f, sizeof(DOS_FILE));
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dos_unmount(fs);
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return 0;
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}
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#endif /* !LIBSA_NO_FS_CLOSE */
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/*
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* Return some stat information on a file.
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*/
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int
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dosfs_stat(struct open_file * fd, struct stat * sb)
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{
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DOS_FILE *f = (DOS_FILE *) fd->f_fsdata;
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/* only important stuff */
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sb->st_mode = (f->de.deAttributes & ATTR_DIRECTORY) ?
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(S_IFDIR | 0555) : (S_IFREG | 0444);
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sb->st_nlink = 1;
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sb->st_uid = 0;
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sb->st_gid = 0;
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if ((sb->st_size = fsize(f->fs, &f->de)) == -1)
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return EINVAL;
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return (0);
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}
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/*
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* Parse DOS boot sector
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*/
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static int
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parsebs(DOS_FS * fs, DOS_BS * bs)
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{
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u_int sc;
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if ((bs->jmp[0] != 0x69 &&
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bs->jmp[0] != 0xe9 &&
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(bs->jmp[0] != 0xeb || bs->jmp[2] != 0x90)) ||
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bs->bpb.bpbMedia < 0xf0)
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return EINVAL;
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if (getushort(bs->bpb.bpbBytesPerSec) != SECSIZ)
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return EINVAL;
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if (!(fs->spc = bs->bpb.bpbSecPerClust) || fs->spc & (fs->spc - 1))
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return EINVAL;
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fs->bsize = secbyt(fs->spc);
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fs->bshift = ffs(fs->bsize) - 1;
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if ((fs->spf = getushort(bs->bpb.bpbFATsecs))) {
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if (bs->bpb.bpbFATs != 2)
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return EINVAL;
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if (!(fs->dirents = getushort(bs->bpb.bpbRootDirEnts)))
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return EINVAL;
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} else {
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if (!(fs->spf = getulong(bs->bpb.bpbBigFATsecs)))
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return EINVAL;
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if (!bs->bpb.bpbFATs || bs->bpb.bpbFATs > 16)
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return EINVAL;
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if ((fs->rdcl = getulong(bs->bpb.bpbRootClust)) < LOCLUS)
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return EINVAL;
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}
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if (!(fs->lsnfat = getushort(bs->bpb.bpbResSectors)))
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return EINVAL;
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fs->lsndir = fs->lsnfat + fs->spf * bs->bpb.bpbFATs;
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fs->lsndta = fs->lsndir + entsec(fs->dirents);
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if (!(sc = getushort(bs->bpb.bpbSectors)) &&
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!(sc = getulong(bs->bpb.bpbHugeSectors)))
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return EINVAL;
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if (fs->lsndta > sc)
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return EINVAL;
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if ((fs->xclus = secblk(fs, sc - fs->lsndta) + 1) < LOCLUS)
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return EINVAL;
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fs->fatsz = fs->dirents ? fs->xclus < 0xff6 ? 12 : 16 : 32;
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sc = (secbyt(fs->spf) << 1) / (fs->fatsz >> 2) - 1;
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if (fs->xclus > sc)
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fs->xclus = sc;
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return 0;
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}
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/*
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* Return directory entry from path
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*/
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static int
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namede(DOS_FS * fs, const char *path, const struct direntry ** dep)
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{
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char name[256];
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const struct direntry *de;
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char *s;
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size_t n;
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int err;
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err = 0;
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de = dot;
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if (*path == '/')
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path++;
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while (*path) {
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if (!(s = strchr(path, '/')))
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s = strchr(path, 0);
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if ((n = s - path) > 255)
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return ENAMETOOLONG;
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memcpy(name, path, n);
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name[n] = 0;
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path = s;
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if (!(de->deAttributes & ATTR_DIRECTORY))
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return ENOTDIR;
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if ((err = lookup(fs, stclus(fs->fatsz, de), name, &de)))
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return err;
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if (*path == '/')
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path++;
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}
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*dep = de;
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return 0;
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}
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/*
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* Lookup path segment
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*/
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static int
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lookup(DOS_FS * fs, u_int clus, const char *name, const struct direntry ** dep)
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{
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static DOS_DIR *dir = NULL;
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u_char lfn[261];
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u_char sfn[13];
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u_int nsec, lsec, xdn, chk, sec, ent, x;
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int err = 0, ok, i;
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if (!clus)
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for (ent = 0; ent < 2; ent++)
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if (!strcasecmp(name, dotstr[ent])) {
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*dep = dot + ent;
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return 0;
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}
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if (dir == NULL) {
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dir = alloc(sizeof(DOS_DIR) * DEPSEC);
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if (dir == NULL)
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return (ENOMEM);
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}
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if (!clus && fs->fatsz == 32)
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clus = fs->rdcl;
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nsec = !clus ? entsec(fs->dirents) : fs->spc;
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lsec = 0;
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xdn = chk = 0;
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for (;;) {
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if (!clus && !lsec)
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lsec = fs->lsndir;
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else if (okclus(fs, clus))
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lsec = blklsn(fs, clus);
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else {
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err = EINVAL;
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goto out;
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}
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for (sec = 0; sec < nsec; sec++) {
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if ((err = ioget(fs->fd, lsec + sec, dir, 1)))
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goto out;
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for (ent = 0; ent < DEPSEC; ent++) {
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if (!*dir[ent].de.deName) {
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err = ENOENT;
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goto out;
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}
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|
if (*dir[ent].de.deName != 0xe5) {
|
|
if (dir[ent].de.deAttributes ==
|
|
ATTR_WIN95) {
|
|
x = dir[ent].xde.weCnt;
|
|
if (x & WIN_LAST ||
|
|
(x + 1 == xdn &&
|
|
dir[ent].xde.weChksum ==
|
|
chk)) {
|
|
if (x & WIN_LAST) {
|
|
chk = dir[ent].xde.weChksum;
|
|
x &= WIN_CNT;
|
|
}
|
|
if (x >= 1 && x <= 20) {
|
|
cp_xdnm(lfn, &dir[ent].xde);
|
|
xdn = x;
|
|
continue;
|
|
}
|
|
}
|
|
} else if (!(dir[ent].de.deAttributes &
|
|
ATTR_VOLUME)) {
|
|
if ((ok = xdn == 1)) {
|
|
for (x = 0, i = 0;
|
|
i < 11; i++)
|
|
x = ((((x & 1) << 7) | (x >> 1)) +
|
|
dir[ent].de.deName[i]) & 0xff;
|
|
ok = chk == x &&
|
|
!strcasecmp(name, (const char *) lfn);
|
|
}
|
|
if (!ok) {
|
|
cp_sfn(sfn, &dir[ent].de);
|
|
ok = !strcasecmp(name, (const char *) sfn);
|
|
}
|
|
if (ok) {
|
|
*dep = &dir[ent].de;
|
|
goto out2;
|
|
}
|
|
}
|
|
}
|
|
xdn = 0;
|
|
}
|
|
}
|
|
if (!clus)
|
|
break;
|
|
if ((err = fatget(fs, &clus)))
|
|
goto out;
|
|
if (fatend(fs->fatsz, clus))
|
|
break;
|
|
}
|
|
err = ENOENT;
|
|
out:
|
|
free(dir, sizeof(DOS_DIR) * DEPSEC);
|
|
dir = NULL;
|
|
out2:
|
|
return (err);
|
|
}
|
|
|
|
/*
|
|
* Copy name from extended directory entry
|
|
*/
|
|
static void
|
|
cp_xdnm(u_char * lfn, struct winentry * xde)
|
|
{
|
|
static const struct {
|
|
u_int off;
|
|
u_int dim;
|
|
} ix[3] = {
|
|
{ offsetof(struct winentry, wePart1),
|
|
sizeof(xde->wePart1) / 2 },
|
|
{ offsetof(struct winentry, wePart2),
|
|
sizeof(xde->wePart2) / 2 },
|
|
{ offsetof(struct winentry, wePart3),
|
|
sizeof(xde->wePart3) / 2 }
|
|
};
|
|
u_char *p;
|
|
u_int n, x, c;
|
|
|
|
lfn += 13 * ((xde->weCnt & WIN_CNT) - 1);
|
|
for (n = 0; n < 3; n++)
|
|
for (p = (u_char *) xde + ix[n].off, x = ix[n].dim; x;
|
|
p += 2, x--) {
|
|
if ((c = getushort(p)) && (c < 32 || c > 127))
|
|
c = '?';
|
|
if (!(*lfn++ = c))
|
|
return;
|
|
}
|
|
if (xde->weCnt & WIN_LAST)
|
|
*lfn = 0;
|
|
}
|
|
|
|
/*
|
|
* Copy short filename
|
|
*/
|
|
static void
|
|
cp_sfn(u_char * sfn, struct direntry * de)
|
|
{
|
|
u_char *p;
|
|
int j, i;
|
|
|
|
p = sfn;
|
|
if (*de->deName != ' ') {
|
|
for (j = 7; de->deName[j] == ' '; j--);
|
|
for (i = 0; i <= j; i++)
|
|
*p++ = de->deName[i];
|
|
if (*de->deExtension != ' ') {
|
|
*p++ = '.';
|
|
for (j = 2; de->deExtension[j] == ' '; j--);
|
|
for (i = 0; i <= j; i++)
|
|
*p++ = de->deExtension[i];
|
|
}
|
|
}
|
|
*p = 0;
|
|
if (*sfn == 5)
|
|
*sfn = 0xe5;
|
|
}
|
|
|
|
/*
|
|
* Return size of file in bytes
|
|
*/
|
|
static off_t
|
|
fsize(DOS_FS * fs, struct direntry * de)
|
|
{
|
|
u_long size;
|
|
u_int c;
|
|
int n;
|
|
|
|
if (!(size = getulong(de->deFileSize)) &&
|
|
de->deAttributes & ATTR_DIRECTORY) {
|
|
if (!(c = getushort(de->deStartCluster)))
|
|
size = fs->dirents * sizeof(struct direntry);
|
|
else {
|
|
if ((n = fatcnt(fs, c)) == -1)
|
|
return n;
|
|
size = blkbyt(fs, n);
|
|
}
|
|
}
|
|
return size;
|
|
}
|
|
|
|
/*
|
|
* Count number of clusters in chain
|
|
*/
|
|
static int
|
|
fatcnt(DOS_FS * fs, u_int c)
|
|
{
|
|
int n;
|
|
|
|
for (n = 0; okclus(fs, c); n++)
|
|
if (fatget(fs, &c))
|
|
return -1;
|
|
return fatend(fs->fatsz, c) ? n : -1;
|
|
}
|
|
|
|
/*
|
|
* Get next cluster in cluster chain
|
|
*/
|
|
static int
|
|
fatget(DOS_FS * fs, u_int * c)
|
|
{
|
|
u_char buf[4];
|
|
u_int x;
|
|
int err;
|
|
|
|
err = ioread(fs, secbyt(fs->lsnfat) + fatoff(fs->fatsz, *c), buf,
|
|
fs->fatsz != 32 ? 2 : 4);
|
|
if (err)
|
|
return err;
|
|
x = fs->fatsz != 32 ? getushort(buf) : getulong(buf);
|
|
*c = fs->fatsz == 12 ? *c & 1 ? x >> 4 : x & 0xfff : x;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Is cluster an end-of-chain marker?
|
|
*/
|
|
static int
|
|
fatend(u_int sz, u_int c)
|
|
{
|
|
return c > (sz == 12 ? 0xff7U : sz == 16 ? 0xfff7U : 0xffffff7);
|
|
}
|
|
|
|
/*
|
|
* Offset-based I/O primitive
|
|
*/
|
|
static int
|
|
ioread(DOS_FS * fs, u_int offset, void *buf, u_int nbyte)
|
|
{
|
|
char *s;
|
|
u_int off, n;
|
|
int err;
|
|
|
|
s = buf;
|
|
if ((off = offset & (SECSIZ - 1))) {
|
|
offset -= off;
|
|
if ((err = iobuf(fs, bytsec(offset))))
|
|
return err;
|
|
offset += SECSIZ;
|
|
if ((n = SECSIZ - off) > nbyte)
|
|
n = nbyte;
|
|
memcpy(s, fs->buf + off, n);
|
|
s += n;
|
|
nbyte -= n;
|
|
}
|
|
n = nbyte & (SECSIZ - 1);
|
|
if (nbyte -= n) {
|
|
if ((err = ioget(fs->fd, bytsec(offset), s, bytsec(nbyte))))
|
|
return err;
|
|
offset += nbyte;
|
|
s += nbyte;
|
|
}
|
|
if (n) {
|
|
if ((err = iobuf(fs, bytsec(offset))))
|
|
return err;
|
|
memcpy(s, fs->buf, n);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Buffered sector-based I/O primitive
|
|
*/
|
|
static int
|
|
iobuf(DOS_FS * fs, u_int lsec)
|
|
{
|
|
int err;
|
|
|
|
if (fs->bufsec != lsec) {
|
|
if ((err = ioget(fs->fd, lsec, fs->buf, 1)))
|
|
return err;
|
|
fs->bufsec = lsec;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Sector-based I/O primitive
|
|
*/
|
|
static int
|
|
ioget(struct open_file * fd, u_int lsec, void *buf, u_int nsec)
|
|
{
|
|
size_t rsize;
|
|
int err;
|
|
|
|
#ifndef LIBSA_NO_TWIDDLE
|
|
twiddle();
|
|
#endif
|
|
err = DEV_STRATEGY(fd->f_dev)(fd->f_devdata, F_READ, lsec,
|
|
secbyt(nsec), buf, &rsize);
|
|
return (err);
|
|
}
|