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- /* io.c - Virtual disk input/output */
- /* Written 1993 by Werner Almesberger */
- /*
- * 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> */
- #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 */
- #undef llseek
- static 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)
- #endif
- void fs_open(char *path,int rw)
- {
- struct stat stbuf;
- if ((fd = open(path,rw ? O_RDWR : O_RDONLY)) < 0)
- pdie("open %s",path);
- 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
- }
- 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;
- }
- /* Local Variables: */
- /* tab-width: 8 */
- /* End: */
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