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- /* io.c - Virtual disk input/output
- Copyright (C) 1993 Werner Almesberger <werner.almesberger@lrc.di.epfl.ch>
- Copyright (C) 1998 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
- Copyright (C) 2008-2013 Daniel Baumann <mail@daniel-baumann.ch>
- This program is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- On Debian systems, the complete text of the GNU General Public License
- can be found in /usr/share/common-licenses/GPL-3 file.
- */
- /*
- * Thu Feb 26 01:15:36 CET 1998: Martin Schulze <joey@infodrom.north.de>
- * Fixed nasty bug that caused every file with a name like
- * xxxxxxxx.xxx to be treated as bad name that needed to be fixed.
- */
- /* FAT32, VFAT, Atari format support, and various fixes additions May 1998
- * by Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de> */
- #define _LARGEFILE64_SOURCE
- #include <sys/types.h>
- #include <stdlib.h>
- #include <stdio.h>
- #include <string.h>
- #include <unistd.h>
- #include <sys/stat.h>
- #include <sys/ioctl.h>
- #include <errno.h>
- #include <fcntl.h>
- #include <linux/fd.h>
- #include "dosfsck.h"
- #include "common.h"
- #include "io.h"
- typedef struct _change {
- void *data;
- loff_t pos;
- int size;
- struct _change *next;
- } CHANGE;
- static CHANGE *changes, *last;
- static int fd, did_change = 0;
- unsigned device_no;
- #ifdef __DJGPP__
- #include "volume.h" /* DOS lowlevel disk access functions */
- loff_t llseek(int fd, loff_t offset, int whence)
- {
- if ((whence != SEEK_SET) || (fd == 4711))
- return -1; /* only those supported */
- return VolumeSeek(offset);
- }
- #define open OpenVolume
- #define close CloseVolume
- #define read(a,b,c) ReadVolume(b,c)
- #define write(a,b,c) WriteVolume(b,c)
- #else
- loff_t llseek(int fd, loff_t offset, int whence)
- {
- return (loff_t) lseek64(fd, (off64_t) offset, whence);
- }
- #endif
- void fs_open(char *path, int rw)
- {
- struct stat stbuf;
- if ((fd = open(path, rw ? O_RDWR : O_RDONLY)) < 0) {
- perror("open");
- exit(6);
- }
- changes = last = NULL;
- did_change = 0;
- #ifndef _DJGPP_
- if (fstat(fd, &stbuf) < 0)
- pdie("fstat %s", path);
- device_no = S_ISBLK(stbuf.st_mode) ? (stbuf.st_rdev >> 8) & 0xff : 0;
- #else
- if (IsWorkingOnImageFile()) {
- if (fstat(GetVolumeHandle(), &stbuf) < 0)
- pdie("fstat image %s", path);
- device_no = 0;
- } else {
- /* return 2 for floppy, 1 for ramdisk, 7 for loopback */
- /* used by boot.c in Atari mode: floppy always FAT12, */
- /* loopback / ramdisk only FAT12 if usual floppy size, */
- /* harddisk always FAT16 on Atari... */
- device_no = (GetVolumeHandle() < 2) ? 2 : 1;
- /* telling "floppy" for A:/B:, "ramdisk" for the rest */
- }
- #endif
- }
- /**
- * Read data from the partition, accounting for any pending updates that are
- * queued for writing.
- *
- * @param[in] pos Byte offset, relative to the beginning of the partition,
- * at which to read
- * @param[in] size Number of bytes to read
- * @param[out] data Where to put the data read
- */
- void fs_read(loff_t pos, int size, void *data)
- {
- CHANGE *walk;
- int got;
- if (llseek(fd, pos, 0) != pos)
- pdie("Seek to %lld", pos);
- if ((got = read(fd, data, size)) < 0)
- pdie("Read %d bytes at %lld", size, pos);
- if (got != size)
- die("Got %d bytes instead of %d at %lld", got, size, pos);
- for (walk = changes; walk; walk = walk->next) {
- if (walk->pos < pos + size && walk->pos + walk->size > pos) {
- if (walk->pos < pos)
- memcpy(data, (char *)walk->data + pos - walk->pos, min(size,
- walk->size
- - pos +
- walk->pos));
- else
- memcpy((char *)data + walk->pos - pos, walk->data,
- min(walk->size, size + pos - walk->pos));
- }
- }
- }
- int fs_test(loff_t pos, int size)
- {
- void *scratch;
- int okay;
- if (llseek(fd, pos, 0) != pos)
- pdie("Seek to %lld", pos);
- scratch = alloc(size);
- okay = read(fd, scratch, size) == size;
- free(scratch);
- return okay;
- }
- void fs_write(loff_t pos, int size, void *data)
- {
- CHANGE *new;
- int did;
- if (write_immed) {
- did_change = 1;
- if (llseek(fd, pos, 0) != pos)
- pdie("Seek to %lld", pos);
- if ((did = write(fd, data, size)) == size)
- return;
- if (did < 0)
- pdie("Write %d bytes at %lld", size, pos);
- die("Wrote %d bytes instead of %d at %lld", did, size, pos);
- }
- new = alloc(sizeof(CHANGE));
- new->pos = pos;
- memcpy(new->data = alloc(new->size = size), data, size);
- new->next = NULL;
- if (last)
- last->next = new;
- else
- changes = new;
- last = new;
- }
- static void fs_flush(void)
- {
- CHANGE *this;
- int size;
- while (changes) {
- this = changes;
- changes = changes->next;
- if (llseek(fd, this->pos, 0) != this->pos)
- fprintf(stderr,
- "Seek to %lld failed: %s\n Did not write %d bytes.\n",
- (long long)this->pos, strerror(errno), this->size);
- else if ((size = write(fd, this->data, this->size)) < 0)
- fprintf(stderr, "Writing %d bytes at %lld failed: %s\n", this->size,
- (long long)this->pos, strerror(errno));
- else if (size != this->size)
- fprintf(stderr, "Wrote %d bytes instead of %d bytes at %lld."
- "\n", size, this->size, (long long)this->pos);
- free(this->data);
- free(this);
- }
- }
- int fs_close(int write)
- {
- CHANGE *next;
- int changed;
- changed = ! !changes;
- if (write)
- fs_flush();
- else
- while (changes) {
- next = changes->next;
- free(changes->data);
- free(changes);
- changes = next;
- }
- if (close(fd) < 0)
- pdie("closing file system");
- return changed || did_change;
- }
- int fs_changed(void)
- {
- return ! !changes || did_change;
- }
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