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441 lines
10 KiB
441 lines
10 KiB
/* Copyright 1986-1992 Emmet P. Gray.
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* Copyright 1996-2002,2006-2009 Alain Knaff.
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* This file is part of mtools.
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*
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* Mtools is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Mtools is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Mtools. If not, see <http://www.gnu.org/licenses/>.
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*
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* Initialize an MSDOS diskette. Read the boot sector, and switch to the
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* proper floppy disk device to match the format on the disk. Sets a bunch
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* of global variables. Returns 0 on success, or 1 on failure.
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*/
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#include "sysincludes.h"
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#include "msdos.h"
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#include "stream.h"
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#include "mtools.h"
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#include "fsP.h"
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#include "plain_io.h"
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#include "floppyd_io.h"
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#include "xdf_io.h"
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#include "buffer.h"
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#include "file_name.h"
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#define FULL_CYL
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/*
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* Read the boot sector. We glean the disk parameters from this sector.
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*/
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static int read_boot(Stream_t *Stream, union bootsector * boot, int size)
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{
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size_t boot_sector_size; /* sector size, as stored in boot sector */
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/* read the first sector, or part of it */
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if(!size)
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size = BOOTSIZE;
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if(size > MAX_BOOT)
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size = MAX_BOOT;
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if (force_read(Stream, boot->characters, 0, size) != size)
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return -1;
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boot_sector_size = WORD(secsiz);
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if(boot_sector_size < sizeof(boot->bytes)) {
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/* zero rest of in-memory boot sector */
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memset(boot->bytes+boot_sector_size, 0,
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sizeof(boot->bytes) - boot_sector_size);
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}
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return 0;
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}
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static int fs_flush(Stream_t *Stream)
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{
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DeclareThis(Fs_t);
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fat_write(This);
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return 0;
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}
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static doscp_t *get_dosConvert(Stream_t *Stream)
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{
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DeclareThis(Fs_t);
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return This->cp;
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}
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Class_t FsClass = {
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read_pass_through, /* read */
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write_pass_through, /* write */
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fs_flush,
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fs_free, /* free */
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0, /* set geometry */
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get_data_pass_through,
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0, /* pre allocate */
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get_dosConvert, /* dosconvert */
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0 /* discard */
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};
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/**
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* Get media type byte from boot sector (BIOS Parameter Block 2) or
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* from FAT (if media byte from BPB 2 looks fishy)
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* Return the media byte + 0x100 if found in BPB 2, or as is if found in FAT.
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*/
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static int get_media_type(Stream_t *St, union bootsector *boot)
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{
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int media;
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media = boot->boot.descr;
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if(media < 0xf0){
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char temp[512];
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/* old DOS disk. Media descriptor in the first FAT byte */
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/* we assume 512-byte sectors here */
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if (force_read(St,temp,(mt_off_t) 512,512) == 512)
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media = (unsigned char) temp[0];
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else
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media = 0;
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} else
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media += 0x100;
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return media;
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}
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Stream_t *GetFs(Stream_t *Fs)
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{
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while(Fs && Fs->Class != &FsClass)
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Fs = Fs->Next;
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return Fs;
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}
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/**
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* Tries out all device definitions for the given drive number, until one
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* is found that is able to read from the device
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* Parameters
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* - drive: drive letter to check
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* - mode: file open mode
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* - out_dev: device parameters (geometry, etc.) are returned here
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* - boot: boot sector is read from the disk into this structure
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* - name: "name" of device definition (returned)
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* - media: media byte is returned here (ored with 0x100 if there is a
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* BIOS Parameter block present)
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* - maxSize: maximal size supported by (physical) drive returned here
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* - isRop: whether device is read-only is returned here
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* Return value:
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* - a Stream allowing to read from this device, must be closed by caller
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*/
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Stream_t *find_device(char drive, int mode, struct device *out_dev,
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union bootsector *boot,
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char *name, int *media, mt_size_t *maxSize,
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int *isRop)
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{
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char errmsg[200];
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Stream_t *Stream;
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struct device *dev;
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int r;
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int isRo=0;
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Stream = NULL;
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sprintf(errmsg, "Drive '%c:' not supported", drive);
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/* open the device */
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for (dev=devices; dev->name; dev++) {
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FREE(&Stream);
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if (dev->drive != drive)
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continue;
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*out_dev = *dev;
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expand(dev->name,name);
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#ifdef USING_NEW_VOLD
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strcpy(name, getVoldName(dev, name));
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#endif
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Stream = 0;
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if(out_dev->misc_flags & FLOPPYD_FLAG) {
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Stream = 0;
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#ifdef USE_FLOPPYD
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Stream = FloppydOpen(out_dev, name, mode,
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errmsg, maxSize);
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#endif
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} else {
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#ifdef USE_XDF
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Stream = XdfOpen(out_dev, name, mode, errmsg, 0);
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if(Stream) {
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out_dev->use_2m = 0x7f;
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if(maxSize)
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*maxSize = max_off_t_31;
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}
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#endif
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if (!Stream)
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Stream = SimpleFileOpen(out_dev, dev, name,
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isRop ? mode | O_RDWR: mode,
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errmsg, 0, 1, maxSize);
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if(Stream) {
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isRo=0;
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} else if(isRop &&
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(errno == EPERM || errno == EACCES || errno == EROFS)) {
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Stream = SimpleFileOpen(out_dev, dev, name,
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mode | O_RDONLY,
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errmsg, 0, 1, maxSize);
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if(Stream) {
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isRo=1;
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}
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}
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}
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if( !Stream)
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continue;
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/* read the boot sector */
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if ((r=read_boot(Stream, boot, out_dev->blocksize)) < 0){
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sprintf(errmsg,
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"init %c: could not read boot sector",
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drive);
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continue;
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}
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if((*media= get_media_type(Stream, boot)) <= 0xf0 ){
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if (boot->boot.jump[2]=='L')
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sprintf(errmsg,
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"diskette %c: is Linux LILO, not DOS",
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drive);
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else
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sprintf(errmsg,"init %c: non DOS media", drive);
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continue;
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}
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/* set new parameters, if needed */
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errno = 0;
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if(SET_GEOM(Stream, out_dev, dev, *media, boot)){
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if(errno)
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#ifdef HAVE_SNPRINTF
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snprintf(errmsg, 199,
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"Can't set disk parameters for %c: %s",
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drive, strerror(errno));
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#else
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sprintf(errmsg,
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"Can't set disk parameters for %c: %s",
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drive, strerror(errno));
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#endif
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else
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sprintf(errmsg,
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"Can't set disk parameters for %c",
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drive);
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continue;
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}
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break;
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}
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/* print error msg if needed */
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if ( dev->drive == 0 ){
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FREE(&Stream);
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fprintf(stderr,"%s\n",errmsg);
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return NULL;
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}
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if(isRop)
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*isRop = isRo;
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return Stream;
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}
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Stream_t *fs_init(char drive, int mode, int *isRop)
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{
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int blocksize;
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int media;
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int disk_size = 0; /* In case we don't happen to set this below */
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size_t tot_sectors;
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char name[EXPAND_BUF];
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int cylinder_size;
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struct device dev;
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mt_size_t maxSize;
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union bootsector boot;
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Fs_t *This;
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This = New(Fs_t);
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if (!This)
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return NULL;
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This->Direct = NULL;
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This->Next = NULL;
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This->refs = 1;
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This->Buffer = 0;
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This->Class = &FsClass;
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This->preallocatedClusters = 0;
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This->lastFatSectorNr = 0;
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This->lastFatAccessMode = 0;
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This->lastFatSectorData = 0;
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This->drive = drive;
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This->last = 0;
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This->Direct = find_device(drive, mode, &dev, &boot, name, &media,
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&maxSize, isRop);
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if(!This->Direct)
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return NULL;
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cylinder_size = dev.heads * dev.sectors;
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This->serialized = 0;
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if ((media & ~7) == 0xf8){
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/* This bit of code is only entered if there is no BPB, or
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* else result of the AND would be 0x1xx
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*/
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struct OldDos_t *params=getOldDosByMedia(media);
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if(params == NULL)
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return NULL;
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This->cluster_size = params->cluster_size;
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tot_sectors = cylinder_size * params->tracks;
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This->fat_start = 1;
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This->fat_len = params->fat_len;
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This->dir_len = params->dir_len;
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This->num_fat = 2;
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This->sector_size = 512;
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This->sectorShift = 9;
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This->sectorMask = 511;
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This->fat_bits = 12;
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} else {
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struct label_blk_t *labelBlock;
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int i;
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This->sector_size = WORD_S(secsiz);
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if(This->sector_size > MAX_SECTOR){
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fprintf(stderr,"init %c: sector size too big\n", drive);
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return NULL;
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}
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i = log_2(This->sector_size);
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if(i == 24) {
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fprintf(stderr,
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"init %c: sector size (%d) not a small power of two\n",
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drive, This->sector_size);
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return NULL;
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}
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This->sectorShift = i;
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This->sectorMask = This->sector_size - 1;
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/*
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* all numbers are in sectors, except num_clus
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* (which is in clusters)
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*/
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tot_sectors = WORD_S(psect);
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if(!tot_sectors)
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tot_sectors = DWORD_S(bigsect);
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This->cluster_size = boot.boot.clsiz;
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This->fat_start = WORD_S(nrsvsect);
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This->fat_len = WORD_S(fatlen);
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This->dir_len = WORD_S(dirents) * MDIR_SIZE / This->sector_size;
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This->num_fat = boot.boot.nfat;
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if (This->fat_len) {
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labelBlock = &boot.boot.ext.old.labelBlock;
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} else {
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labelBlock = &boot.boot.ext.fat32.labelBlock;
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}
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if(has_BPB4) {
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This->serialized = 1;
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This->serial_number = _DWORD(labelBlock->serial);
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}
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}
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if (tot_sectors >= (maxSize >> This->sectorShift)) {
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fprintf(stderr, "Big disks not supported on this architecture\n");
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exit(1);
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}
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/* full cylinder buffering */
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#ifdef FULL_CYL
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disk_size = (dev.tracks) ? cylinder_size : 512;
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#else /* FULL_CYL */
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disk_size = (dev.tracks) ? dev.sectors : 512;
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#endif /* FULL_CYL */
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#if (defined OS_sysv4 && !defined OS_solaris)
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/*
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* The driver in Dell's SVR4 v2.01 is unreliable with large writes.
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*/
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disk_size = 0;
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#endif /* (defined sysv4 && !defined(solaris)) */
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#ifdef OS_linux
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disk_size = cylinder_size;
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#endif
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#if 1
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if(disk_size > 256) {
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disk_size = dev.sectors;
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if(dev.sectors % 2)
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disk_size <<= 1;
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}
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#endif
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if (disk_size % 2)
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disk_size *= 2;
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if(!dev.blocksize || dev.blocksize < This->sector_size)
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blocksize = This->sector_size;
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else
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blocksize = dev.blocksize;
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if (disk_size)
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This->Next = buf_init(This->Direct,
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8 * disk_size * blocksize,
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disk_size * blocksize,
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This->sector_size);
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else
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This->Next = This->Direct;
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if (This->Next == NULL) {
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perror("init: allocate buffer");
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This->Next = This->Direct;
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}
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/* read the FAT sectors */
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if(fat_read(This, &boot, tot_sectors, dev.use_2m&0x7f)){
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This->num_fat = 1;
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FREE(&This->Next);
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Free(This->Next);
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return NULL;
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}
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/* Set the codepage */
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This->cp = cp_open(dev.codepage);
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if(This->cp == NULL) {
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fs_free((Stream_t *)This);
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FREE(&This->Next);
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Free(This->Next);
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return NULL;
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}
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return (Stream_t *) This;
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}
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char getDrive(Stream_t *Stream)
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{
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DeclareThis(Fs_t);
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if(This->Class != &FsClass)
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return getDrive(GetFs(Stream));
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else
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return This->drive;
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}
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int fsPreallocateClusters(Fs_t *Fs, long size)
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{
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if(size > 0 && getfreeMinClusters((Stream_t *)Fs, size) != 1)
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return -1;
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Fs->preallocatedClusters += size;
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return 0;
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}
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