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#ifndef HASHTABLE_H
#define HASHTABLE_H
#include <stdio.h>
#include <epoch.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
/* This hashtable data structure has a central role in umvu.
* A module adds a hashtable entry to start a virtualization.
* e.g. if it adds a CHECKPATH element it means that the module
* virtualizes a subtree of the file system, if it adds
* a CHECKSOCKET it virtualizes an address family */
struct vuht_entry_t;
struct vu_service_t;
#define PSEUDO_CHECK 0x80
/* Supported object types */
#define CHECKMODULE 0 // Module name
#define CHECKPATH 1 // Path
#define CHECKSOCKET 2 // Address Family
#define CHECKCHRDEVICE 3 // chr device maj/min
#define CHECKBLKDEVICE 4 // blk device
#define CHECKSC 5 // Syscall #
#define CHECKIOCTL 6 // ioctl request
#define CHECKBINFMT 7 // Binfmt search
#define CHECKFSALIAS 8 // FSAlias (just a string->string matching)
#define NCHECKS 9
#define CHECKFSTYPE (PSEUDO_CHECK | CHECKMODULE)
#define CHECKPATHEXACT (PSEUDO_CHECK | CHECKPATH)
#define SET_EPOCH 1
#define NEGATIVE_MOUNT ((confirmfun_t)1)
#define VUFLAG_PERMANENT 1
#define VUFLAG_PREFIX 2
/* hashtable elements may have exception. when a confirm function
is defined (as an argument adding the hashtable element) that
confirm function is called prior to confirm each match */
typedef int (*confirmfun_t)(uint8_t type, void *arg, int arglen,
struct vuht_entry_t *ht);
/* add an element to the hashtable */
/* confirmfun is a cleanup function for CHECKMODULE */
struct vuht_entry_t *vuht_add(uint8_t type, const void *obj, int objlen,
struct vu_service_t *service, int vuflags,
confirmfun_t confirmfun, void *private_data);
/* add a path element to the hashtable: This function is similar to vuht_add
* extra parameters are provided to generate teh mounttab line (see /proc/mounts) */
struct vuht_entry_t *vuht_pathadd(uint8_t type, const char *source,
const char *path, const char *fstype,
unsigned long mountflags, const char *mountopts,
struct vu_service_t *service, int vuflags,
confirmfun_t confirmfun, void *private_data);
/* del takes the element out from the data structure.... */
/* supported flags: MNT_FORCE MNT_DETACH (both provide
immediate detach and lazy delete) */
int vuht_del(struct vuht_entry_t *hte, int umountflags);
/* pick searches an entry in this hashtable.
pick and drop respectively increment/decrement the usage count
of the hashtable element to check if it is in use and to implemented
delayed delection */
struct vuht_entry_t *vuht_pick(uint8_t type, void *arg, struct stat *st, int setepoch);
/* increment the usage count of the hash table element */
void vuht_pick_again(struct vuht_entry_t *hte);
/* decrement the usage count of the hash table element.
* the element is deallocated when count is 0 */
void vuht_drop(struct vuht_entry_t *hte);
void forall_vuht_do(uint8_t type,
void (*fun)(struct vuht_entry_t *ht, void *arg),
void *arg);
/* write the mount table in f.
It is in the format of /proc/mounts or /etc/mtab */
void vuht_get_mtab(FILE *f);
/* return the object i.e. the key of hte */
const void *vuht_get_obj(struct vuht_entry_t *hte);
/* modules get the relative path to the mountpoint
this function converts paths to paths-for-modules (mpaths) */
const char *vuht_path2mpath(struct vuht_entry_t *hte, const char *path);
/* each hashtable entry has a private data field */
void *vuht_get_private_data(struct vuht_entry_t *hte);
void vuht_set_private_data(struct vuht_entry_t *hte, void *private_data);
/* set the cleanup function for modules */
void vuht_set_service_cleanupfun(struct vuht_entry_t *hte, confirmfun_t cleanup_fun);
/* change the epoch of a hashtable entry to the current epoch (it this useful? )*/
// void vuht_renew(struct vuht_entry_t *hte);
//char *vuht_get_servicename(struct vuht_entry_t *hte);
struct vu_service_t *vuht_get_service(struct vuht_entry_t *hte);
unsigned long vuht_get_mountflags(struct vuht_entry_t *hte);
epoch_t vuht_get_vepoch(struct vuht_entry_t *hte);
int vuht_get_count(struct vuht_entry_t *hte);
int vuht_get_objlen(struct vuht_entry_t *hte);
void vuht_terminate();
#endif
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