/*
* sys_getdirentry
*/
int
sys_getdirentry(int fd, userptr_t buf, size_t buflen, int *retval)
{
DEBUG(DB_VFS, "*** getdirentry %d\n", fd);
struct vnode *vn;
off_t offset = 0;
int err;
struct uio my_uio;
struct iovec uio_iov;
/* Check if fd is a valid file descriptor. */
struct filetable *ft = curthread->t_filetable;
spinlock_acquire(&ft->ft_spinlock);
/* If fd is not a valid file descriptor, or was not opened for reading,
* return error */
if ((fd < 0) || (fd >= __OPEN_MAX) || (ft->ft_entries[fd] == NULL) ||
(ft->ft_entries[fd]->ft_vnode == NULL)) {
spinlock_release(&ft->ft_spinlock);
return EBADF;
}
int how = ft->ft_entries[fd]->ft_flags & O_ACCMODE;
if ((how != O_RDONLY) && (how != O_RDWR)) {
spinlock_release(&ft->ft_spinlock);
return EBADF;
}
/* Initialize vn and offset using your filetable info for fd */
vn = ft->ft_entries[fd]->ft_vnode;
offset = ft->ft_entries[fd]->ft_pos;
/* set up a uio with the buffer, its size, and the current offset */
mk_useruio(&uio_iov, &my_uio, buf, buflen, offset, UIO_READ);
/* does the read */
err = VOP_GETDIRENTRY(vn, &my_uio);
if (err) {
spinlock_release(&ft->ft_spinlock);
return err;
}
/* Set the offset to the updated offset in the uio.
* Save the new offset with your filetable info for fd.
*/
offset = my_uio.uio_offset;
ft->ft_entries[fd]->ft_pos = offset;
/*
* the amount read is the size of the buffer originally, minus
* how much is left in it. Note: it is not correct to use
* uio_offset for this!
*/
*retval = buflen - my_uio.uio_resid;
spinlock_release(&ft->ft_spinlock);
return 0;
}
/*
* sys_getdirentry
*/
int
sys_getdirentry(int fd, userptr_t buf, size_t buflen, int *retval)
{
struct filetable *file_table = curthread->t_filetable;
spinlock_acquire(&file_table->filetable_lock);
//kprintf("doing get dir");
//check the fd is valid or not like we do in file_close
if((fd > __OPEN_MAX) || (curthread->t_filetable->ft_entries[fd] == NULL) || (fd<0)){
return EBADF;
}
//check the flag
int how;
how = file_table->ft_entries[fd]->flags & O_ACCMODE;
if(how == O_WRONLY){
spinlock_release(&file_table->filetable_lock);
return EBADF;
}
//construct uio
struct uio user_uio;
struct iovec user_iov;
int offset = file_table->ft_entries[fd]->pos;
mk_useruio(&user_iov, &user_uio, buf, buflen, offset, UIO_READ);
int result;
struct vnode *vn;
vn = file_table->ft_entries[fd]->file_vnode;
//read the file into uio
result = VOP_GETDIRENTRY(vn,&user_uio);
//if fail
if(result){
spinlock_release(&file_table->filetable_lock);
return result;
}
//on success upadate the offset
file_table->ft_entries[fd]->pos = user_uio.uio_offset;
//set retval to be the amount we read
*retval = buflen - user_uio.uio_resid;
spinlock_release(&file_table->filetable_lock);
//kprintf("get dir done");
return 0;
}
