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#ifndef VU_VNODE_H
#define VU_VNODE_H
/* This if the table of vnodes.
*
* NB there are three layers of data structures:
* fd_table, file_table (whose elements are named fnodes), vnode (this).
* more elements of fd_table may point to the same fnode, several fnodes to the same vnode.
*
* dup/inherited file descriptors from fd_table point the same fnode element.
* fnodes point to the same vnode element if they refer to the same file.
*
* This module perform locking to support multithreading access
*/
struct vu_node_t;
struct vuht_entry_t;
/* open/close a vnode element ht+dev+inode together are the unique identifier
of a vnode, open creates a new element if that file has not been opened yet,
otherwise it returns the pointer to the corresponding vnode (and increment
the usage counter)
*/
struct vu_vnode_t *vu_vnode_open(struct vuht_entry_t *ht, ino_t dev, ino_t inode, off_t size,
int trunc);
/* close decrements the usage counter, delete the local copy and free the vnode when
the counter becomes zero) */
void vu_vnode_close(struct vu_vnode_t *vnode);
/* this is the pathname of a real file, local "image" of a virtual file.
it is often an empty file used to open "something" in the user process to
allocate a file descriptor.
The original contents of the file is loaded to support mmap or execve */
char *vu_vnode_getvpath(struct vu_vnode_t *vnode);
typedef int (*copyfun) (struct vuht_entry_t *ht, char *path, char *tmp_path);
int vu_vnode_copyinout (struct vu_vnode_t *vnode, char *path, copyfun cp);
/* VU_USE_PRW: get and set size + locking */
off_t vu_vnode_get_size_lock(struct vu_vnode_t *vnode);
void vu_vnode_set_size_unlock(struct vu_vnode_t *vnode, off_t size);
off_t vu_vnode_getset_size(struct vuht_entry_t *ht, ino_t dev, ino_t inode, off_t size);
#endif
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