#define FUSE_USE_VERSION 26

#include <sys/fsuid.h>
#include <sys/types.h>
#include <pthread.h>
#include <signal.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>

/*
 * Global variables for AppFS caching
 */
pthread_mutex_t appfs_path_info_cache_mutex = PTHREAD_MUTEX_INITIALIZER;
int appfs_path_info_cache_size = 8209;
struct appfs_pathinfo *appfs_path_info_cache = NULL;

/*
 * Global variables for AppFS Tcl Interpreter restarting
 */
int interp_reset_key = 0;

/*
 * AppFS Path Type:  Describes the type of path a given file is
 */
typedef enum {
	APPFS_PATHTYPE_INVALID,
	APPFS_PATHTYPE_DOES_NOT_EXIST,
	APPFS_PATHTYPE_FILE,

/*
 * Return the thread-specific Tcl interpreter, creating it if needed
 */
static Tcl_Interp *appfs_TclInterp(void) {
	Tcl_Interp *interp;
	int pthread_ret;
	static __thread int thread_interp_reset_key = 0;

	interp = pthread_getspecific(interpKey);
	if (interp != NULL && thread_interp_reset_key != interp_reset_key) {
		APPFS_DEBUG("Terminating old interpreter and restarting due to reset request.");

		Tcl_DeleteInterp(interp);

		interp = NULL;
	}

	if (interp == NULL) {
		interp = appfs_create_TclInterp(NULL);

		if (interp == NULL) {
			return(NULL);
		}

	if (retval != TCL_OK) {
		APPFS_DEBUG("Tcl command failed, ::errorInfo contains: %s\n", Tcl_GetVar(interp, "::errorInfo", 0));
	}

	return(retval);
}

/*
 * Request all Tcl interpreters restart
 */
static void appfs_tcl_ResetInterps(void) {
	APPFS_DEBUG("Requesting reset of all interpreters.");

	__sync_add_and_fetch(&interp_reset_key, 1);

	return;
}

/*
 * Determine the UID for the user making the current FUSE filesystem request.
 * This will be used to lookup the user's home directory so we can search for
 * locally modified files.
 */
static uid_t appfs_get_fsuid(void) {

	return;
}

static void appfs_get_path_info_cache_flush(uid_t uid, int new_size) {
	unsigned int idx;
	int pthread_ret;

	APPFS_DEBUG("Flushing AppFS cache (uid = %lli, new_size = %i)", (long long) uid, new_size);

	pthread_ret = pthread_mutex_lock(&appfs_path_info_cache_mutex);
	if (pthread_ret != 0) {
		APPFS_DEBUG("Unable to lock path_info cache mutex !");

		return;
	}

	Tcl_CreateObjCommand(interp, "appfsd::simulate_user_fs_leave", tcl_appfs_simulate_user_fs_leave, NULL, NULL);
	Tcl_CreateObjCommand(interp, "appfsd::get_path_info_cache_flush", tcl_appfs_get_path_info_cache_flush, NULL, NULL);

	Tcl_PkgProvide(interp, "appfsd", "1.0");

	return(TCL_OK);
}

/*
 * Hot-restart support
 */
/* Initiate a hot-restart */
static void appfs_hot_restart(void) {
	appfs_tcl_ResetInterps();
	appfs_get_path_info_cache_flush(-1, -1);

	return;
}

/*
 * Signal handler to initiate a hot-restart
 */
static void appfs_signal_handler(int sig) {
	/* Do not handle signals until FUSE has been started */
	if (!appfs_fuse_started) {
		return;
	}

	if (sig == SIGHUP) {
		appfs_hot_restart();
	}

	return;
}

/*
 * FUSE operations structure
 */
static struct fuse_operations appfs_operations = {
	.getattr   = appfs_fuse_getattr,
	.readdir   = appfs_fuse_readdir,

 * Entry point into this program.
 */
int main(int argc, char **argv) {
	Tcl_Interp *test_interp;
	char *test_interp_error;
	struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
	int pthread_ret;
	void *signal_ret;

	/*
	 * Skip passed program name
	 */
	if (argc == 0 || argv == NULL) {
		return(1);
	}

		fprintf(stderr, "Unable to initialize Tcl interpreter for AppFSd:\n");
		fprintf(stderr, "%s\n", test_interp_error);

		return(1);
	}
	Tcl_DeleteInterp(test_interp);

	/*
	 * Register a signal handler for hot-restart requests
	 */
	signal_ret = signal(SIGHUP, appfs_signal_handler);
	if (signal_ret == SIG_ERR) {
		fprintf(stderr, "Unable to install signal handler for hot-restart\n");
		fprintf(stderr, "Hot-restart will not be available.\n");
	}

	/*
	 * Add FUSE arguments which we always supply
	 */
	fuse_opt_parse(&args, NULL, NULL, appfs_fuse_opt_cb);
	fuse_opt_add_arg(&args, "-odefault_permissions,fsname=appfs,subtype=appfsd,use_ino,kernel_cache,entry_timeout=0,attr_timeout=0,intr,big_writes,hard_remove");