Esempio n. 1
0
func Unlink(rip *common.Inode, name string) error {
	if !rip.IsDirectory() {
		return common.ENOTDIR
	}

	dirp := rip

	inum := 0
	err := search_dir(dirp, name, &inum, DELETE)
	return err
}
Esempio n. 2
0
func Link(rip *common.Inode, name string, inum int) error {
	if !rip.IsDirectory() {
		return common.ENOTDIR
	}

	dirp := rip

	// Add the entry to the directory
	err := search_dir(dirp, name, &inum, ENTER)
	return err
}
Esempio n. 3
0
func IsEmpty(rip *common.Inode) bool {
	if !rip.IsDirectory() {
		return false
	}

	dirp := rip

	zeroinode := 0
	if err := search_dir(dirp, "", &zeroinode, IS_EMPTY); err != nil {
		return false
	}
	return true
}
Esempio n. 4
0
func Lookup(rip *common.Inode, name string) (bool, int, int) {
	if !rip.IsDirectory() {
		return false, common.NO_DEV, common.NO_INODE
	}

	dirp := rip

	inum := 0
	err := search_dir(dirp, name, &inum, LOOKUP)
	if err != nil {
		return false, common.NO_DEV, common.NO_INODE
	}

	return true, dirp.Devinfo.Devnum, inum
}
Esempio n. 5
0
func (fs *FileSystem) do_mount(proc *Process, dev common.BlockDevice, path string) error {
	if dev == nil {
		return common.EINVAL
	}

	// scan bitmap block table to see if 'dev' is already mounted
	found := false
	freeIndex := -1
	for i := 0; i < common.NR_DEVICES; i++ {
		if fs.devices[i] == dev {
			found = true
		} else if fs.devices[i] == nil {
			freeIndex = i
		}
	}

	if found {
		return common.EBUSY // already mounted
	}

	if freeIndex == -1 {
		return common.ENFILE // no device slot available
	}

	// Invalidate the cache for this index to be sure
	fs.bcache.Invalidate(freeIndex)

	// Fill in the device info
	devinfo, err := common.GetDeviceInfo(dev)

	// If it a recognized Minix filesystem
	if err != nil {
		return err
	}

	// Create a new allocation table for this device
	alloc := alloctbl.NewAllocTbl(devinfo, fs.bcache, freeIndex)

	// Update the device number/alloc table
	devinfo.Devnum = freeIndex
	devinfo.AllocTbl = alloc

	// Add the device to the block cache/inode table
	fs.bcache.MountDevice(freeIndex, dev, devinfo)
	fs.itable.MountDevice(freeIndex, devinfo)
	fs.devices[freeIndex] = dev
	fs.devinfo[freeIndex] = devinfo

	// Get the inode of the file to be mounted on
	rip, err := fs.eatPath(fs.procs[common.ROOT_PROCESS], path)

	if err != nil {
		// Perform lots of cleanup
		fs.devices[freeIndex] = nil
		fs.devinfo[freeIndex] = nil
		fs.bcache.UnmountDevice(freeIndex)
		fs.itable.UnmountDevice(freeIndex)
		return err
	}

	var r error = nil

	// It may not be busy
	if rip.Count > 1 {
		r = common.EBUSY
	}

	// It may not be spacial
	bits := rip.Type()
	if bits == common.I_BLOCK_SPECIAL || bits == common.I_CHAR_SPECIAL {
		r = common.ENOTDIR
	}

	// Get the root inode of the mounted file system
	var root_ip *common.Inode
	if r == nil {
		root_ip, err = fs.itable.GetInode(freeIndex, common.ROOT_INODE)
		if err != nil {
			r = err
		}
	}

	if root_ip != nil && root_ip.Mode == 0 {
		r = common.EINVAL
	}

	// File types of 'rip' and 'root_ip' may not conflict
	if r == nil {
		if !rip.IsDirectory() && root_ip.IsDirectory() {
			r = common.EISDIR
		}
	}

	// If error, return the bitmap and both inodes; release the maps
	if r != nil {
		// TODO: Refactor this error handling code?
		// Perform lots of cleanup
		fs.devices[freeIndex] = nil
		fs.devinfo[freeIndex] = nil
		fs.bcache.UnmountDevice(freeIndex)
		fs.itable.UnmountDevice(freeIndex)
		return r
	}

	// Nothing else can go wrong, so perform the mount
	minfo := &common.MountInfo{
		MountPoint:  rip,
		MountTarget: root_ip,
	}
	rip.Mounted = minfo     // so we can find the root inode during lookup
	root_ip.Mounted = minfo // so we can easily resolve from a mount target to the mount point

	// Store the mountinfo in the device info table for easy mapping
	devinfo.MountInfo = minfo
	return nil
}