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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;
}
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/* tab-width: 8 */
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