/*
	afuse -	 An automounter using FUSE
	Copyright (C) 2006	Jacob Bower <jacob.bower@ic.ac.uk>

	Portions of this program derive from examples provided with
	FUSE-2.5.2.

	This program can be distributed under the terms of the GNU GPL.
	See the file COPYING.
*/

#include <config.h>

#ifdef linux
// For pread()/pwrite()
#define _XOPEN_SOURCE 500
#endif

#include <fuse.h>
#include <fuse_opt.h>
// for mkdtemp
#define __USE_BSD
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <unistd.h>
#include <alloca.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <stdint.h>
#include <signal.h>
#ifdef HAVE_SETXATTR
#include <sys/xattr.h>
#endif

#include "fd_list.h"
#include "dir_list.h"
#include "utils.h"

#include "variable_pairing_heap.h"

#define TMP_DIR_TEMPLATE "/tmp/afuse-XXXXXX"
char *mount_point_directory;
dev_t mount_point_dev;

// Data structure filled in when parsing command line args
struct user_options_t {
	char *mount_command_template;
	char *unmount_command_template;
	bool flush_writes;
	uint64_t auto_unmount_delay;
} user_options = {NULL, NULL, false, UINT64_MAX};

typedef struct _mount_list_t {
	struct _mount_list_t *next;
	struct _mount_list_t *prev;

	char *root_name;
	char *mount_point;
	fd_list_t *fd_list;
	dir_list_t *dir_list;

	PH_NEW_LINK(struct _mount_list_t) auto_unmount_ph_node;
	/* This is the sort key for the auto_unmount_ph heap.  It will
	   equal UINT64_MAX if this node is not in the heap. */
	int64_t auto_unmount_time;
} mount_list_t;

PH_DECLARE_TYPE(auto_unmount_ph, mount_list_t)
PH_DEFINE_TYPE(auto_unmount_ph, mount_list_t, auto_unmount_ph_node, auto_unmount_time)

#define BLOCK_SIGALRM \
	sigset_t block_sigalrm_oldset, block_sigalrm_set;	\
	sigemptyset(&block_sigalrm_set); \
	sigaddset(&block_sigalrm_set, SIGALRM); \
	sigprocmask(SIG_BLOCK, &block_sigalrm_set, &block_sigalrm_oldset)

#define UNBLOCK_SIGALRM \
	sigprocmask(SIG_SETMASK, &block_sigalrm_oldset, NULL)

auto_unmount_ph_t auto_unmount_ph;
int64_t auto_unmount_next_timeout = INT64_MAX;

static int64_t from_timeval(const struct timeval *tv)
{
	return (int64_t)tv->tv_sec * 1000000 + ((int64_t)tv->tv_usec);
}

static void to_timeval(struct timeval *tv, int64_t usec)
{
	tv->tv_sec = usec / 1000000;
	tv->tv_usec = usec % 1000000;
}

static int get_retval(int res)
{
	if (res == -1)
		return -errno;
	return 0;
}

static int check_mount(mount_list_t *mount)
{
	struct stat buf;

	if (lstat(mount->mount_point, &buf) == -1)
		return 0;
	if (buf.st_dev == mount_point_dev)
		return 0;
	return 1;
}

static void update_auto_unmount(mount_list_t *mount)
{
	if (user_options.auto_unmount_delay == UINT64_MAX)
		return;

	/* Get the current time */
	struct timeval tv;
	mount_list_t *min_mount;
	int64_t cur_time, next_time;
	gettimeofday(&tv, NULL);
	cur_time = from_timeval(&tv);

	if (mount)
	{
		/* Always remove first */
		if (mount->auto_unmount_time != INT64_MAX)
			auto_unmount_ph_remove(&auto_unmount_ph, mount);

		if (!mount->fd_list && !mount->dir_list)
		{
			mount->auto_unmount_time = cur_time + user_options.auto_unmount_delay;
			auto_unmount_ph_insert(&auto_unmount_ph, mount);
		} else
		{
			mount->auto_unmount_time = INT64_MAX;
		}
	}
	min_mount = auto_unmount_ph_min(&auto_unmount_ph);
	next_time = min_mount ? min_mount->auto_unmount_time : INT64_MAX;

	if (next_time != auto_unmount_next_timeout)
	{
		struct itimerval itv;
		auto_unmount_next_timeout = next_time;

		if (next_time != INT64_MAX)
		{
			if (next_time > cur_time)
				to_timeval(&itv.it_value, next_time - cur_time);
			else /* Timer is set to expire immediately --- set it to 1 instead*/
				to_timeval(&itv.it_value, 1);
		} else
		{
			/* Disable the timer */
			to_timeval(&itv.it_value, 0);
		}
		to_timeval(&itv.it_interval, 0);
		if (setitimer(ITIMER_REAL, &itv, NULL) != 0) {
			perror("Error setting timer");
		}
	}
}

static void handle_auto_unmount_timer(int x)
{
	/* Get the current time */
	struct timeval tv;
	int64_t cur_time;
	mount_list_t *mount;
	gettimeofday(&tv, NULL);
	cur_time = from_timeval(&tv);

	while ((mount = auto_unmount_ph_min(&auto_unmount_ph)) != NULL &&
		   mount->auto_unmount_time <= cur_time)
	{
		do_umount(mount);
	}

	update_auto_unmount(NULL);
}

mount_list_t *mount_list = NULL;

mount_list_t *find_mount(const char *root_name)
{
	mount_list_t *current_mount = mount_list;

	while(current_mount) {
		if( strcmp(root_name, current_mount->root_name) == 0)
			return current_mount;

		current_mount = current_mount->next;
	}

	return NULL;
}

int is_mount(const char *root_name)
{
	return find_mount(root_name) ? 1 : 0;
}

mount_list_t *add_mount(const char *root_name, char *mount_point)
{
	mount_list_t *new_mount;

	new_mount = (mount_list_t *)my_malloc( sizeof(mount_list_t) );
	new_mount->root_name = my_strdup(root_name);
	new_mount->mount_point = mount_point;

	new_mount->next = mount_list;
	new_mount->prev = NULL;
	new_mount->fd_list = NULL;
	new_mount->dir_list = NULL;
	new_mount->auto_unmount_time = INT64_MAX;
	if(mount_list)
		mount_list->prev = new_mount;

	mount_list = new_mount;

	update_auto_unmount(new_mount);

	return new_mount;
}

void remove_mount(mount_list_t *current_mount)
{
	if (current_mount->auto_unmount_time != INT64_MAX)
		auto_unmount_ph_remove(&auto_unmount_ph, current_mount);

	free(current_mount->root_name);
	free(current_mount->mount_point);
	if(current_mount->prev)
		current_mount->prev->next = current_mount->next;
	else
		mount_list = current_mount->next;
	if(current_mount->next)
		current_mount->next->prev = current_mount->prev;
	free(current_mount);
	update_auto_unmount(NULL);
}

char *make_mount_point(const char *root_name)
{
	char *dir_tmp;
	int i;

	// Create the mount point
	dir_tmp = my_malloc(strlen(mount_point_directory) + 2 + strlen(root_name));
	strcpy(dir_tmp, mount_point_directory);
	strcat(dir_tmp, "/");
	strcat(dir_tmp, root_name);

	if(mkdir(dir_tmp, 0700) == -1 && errno != EEXIST) {
		fprintf(stderr, "Cannot create directory: %s (%s)\n",
			dir_tmp, strerror(errno));
		free(dir_tmp);
		return NULL;
	}
	return dir_tmp;
}


// !!FIXME!! allow escaping of %'s
// Note: this method strips out quotes and applies them itself as should be appropriate
char *expand_template(const char *template, const char *mount_point, const char *root_name)
{
	int len = 0;
	int i;
	char *expanded_name;
	char *expanded_name_start;

	// calculate length
	for(i = 0; template[i]; i++)
		if(template[i] == '%') {
			switch(template[i + 1])
			{
				case 'm':
					len += strlen(mount_point) + 2;
					i++;
					break;
				case 'r':
					len += strlen(root_name) + 2;
					i++;
					break;
			}
		} else if(template[i] != '"')
			len++;

	expanded_name_start = expanded_name = my_malloc(len + 1);

	for(i = 0; template[i]; i++)
		if(template[i] == '%') {
			int j = 0;
			switch(template[i + 1])
			{
				case 'm':
					*expanded_name++ = '"';
					while(mount_point[j])
						*expanded_name++ = mount_point[j++];
					*expanded_name++ = '"';
					i++;
					break;
				case 'r':
					*expanded_name++ = '"';
					while(root_name[j])
						*expanded_name++ = root_name[j++];
					*expanded_name++ = '"';
					i++;
					break;
			}
		} else if(template[i] != '"')
			*expanded_name++ = template[i];

	*expanded_name = '\0';

	return expanded_name_start;
}

mount_list_t *do_mount(const char *root_name)
{
	char *mount_point;
	char *mount_command;
	mount_list_t *mount;
	int sysret;

	fprintf(stderr, "Mounting: %s\n", root_name);

	if( !(mount_point = make_mount_point(root_name)) ) {
		fprintf(stderr, "Failed to create mount point directory: %s/%s\n",
		        mount_point_directory, root_name);
		return NULL;
	}

	mount_command = expand_template(user_options.mount_command_template,
	                                mount_point, root_name);
	sysret = system(mount_command);

	fprintf(stderr, "sysret: %.8x\n", sysret);

	if(sysret) {
		fprintf(stderr, "Failed to invoke mount command: '%s' (%s)\n",
		        mount_command, sysret != -1 ?
			               "Error executing mount" :
				       strerror(errno));

		// remove the now unused directory
		if( rmdir(mount_point) == -1 )
			fprintf(stderr, "Failed to remove mount point dir: %s (%s)",
				mount_point, strerror(errno));

		free(mount_command);
		free(mount_point);
		return NULL;
	}

	mount = add_mount(root_name, mount_point);

	free(mount_command);
	return mount;
}

int do_umount(mount_list_t *mount)
{
	char *unmount_command;
	int sysret;

	fprintf(stderr, "Unmounting: %s\n", mount->root_name);

	unmount_command = expand_template(user_options.unmount_command_template,
	                                  mount->mount_point, mount->root_name);
	sysret = system(unmount_command);
	if(sysret) {
		fprintf(stderr, "Failed to invoke unmount command: '%s' (%s)\n",
		        unmount_command, sysret != -1 ?
			               "Error executing mount" :
				       strerror(errno));
		/* Still unmount anyway */
	}

	if( rmdir(mount->mount_point) == -1 )
		fprintf(stderr, "Failed to remove mount point dir: %s (%s)",
				mount->mount_point, strerror(errno));
	remove_mount(mount);
	free(unmount_command);
	return 1;
}

void unmount_all(void)
{
	fprintf(stderr, "Attemping to unmount all filesystems:\n");

	while(mount_list) {
		fprintf(stderr, "\tUnmounting: %s\n", mount_list->root_name);

		do_umount(mount_list);
	}

	fprintf(stderr, "done.\n");
}

void shutdown(void)
{
	BLOCK_SIGALRM;

	unmount_all();

	UNBLOCK_SIGALRM;

	if(rmdir(mount_point_directory) == -1)
		fprintf(stderr, "Failed to remove temporary mount point directory: %s (%s)\n",
		        mount_point_directory, strerror(errno));
}

int max_path_out_len(const char *path_in)
{
	return strlen(mount_point_directory) + strlen(path_in) + 2;
}

// returns true if path is the a child directory of a root node
// e.g. /a/b is a child, /a is not.
int extract_root_name(const char *path, char *root_name)
{
	int i;
	int is_child;

	for(i = 1; path[i] && path[i] != '/'; i++)
		root_name[i - 1] = path[i];
	root_name[i - 1] = '\0';

	return strlen(&path[i]);
}

typedef enum {PROC_PATH_FAILED, PROC_PATH_ROOT_DIR, PROC_PATH_PROXY_DIR} proc_result_t;

proc_result_t process_path(const char *path_in, char *path_out, char *root_name, int attempt_mount, mount_list_t **out_mount)
{
	int i;
	char *path_out_base;
	int is_child;
	int len;
	mount_list_t *mount = NULL;

	*out_mount = NULL;

	fprintf(stderr, "Path in: %s\n", path_in);
	is_child = extract_root_name(path_in, root_name);
	fprintf(stderr, "root_name is: %s\n", root_name);

	// Mount filesystem if neccessary
	// the combination of is_child and attempt_mount prevent inappropriate
	// mounting of a filesystem for example if the user tries to mknod
	// in the afuse root this should cause an error not a mount.
	// !!FIXME!! this is broken on FUSE < 2.5 (?) because a getattr
	// on the root node seems to occur with every single access.
	if( /*(is_child || attempt_mount ) &&  */
	   strlen(root_name) > 0            &&
	   !(mount = find_mount(root_name)) &&
	   !(mount = do_mount(root_name)))
		return PROC_PATH_FAILED;

	if (mount && !check_mount(mount))
	{
		do_umount(mount);
		mount = do_mount(root_name);
		if (!mount)
			return PROC_PATH_FAILED;
	}

	// construct path_out (mount_point_directory + '/' + path_in + '\0')
	path_out_base = path_out;
	len = strlen(mount_point_directory);
	memcpy(path_out, mount_point_directory, len);
	path_out += len;
	*path_out++ = '/';
	len = strlen(path_in) - 1;
	memcpy(path_out, path_in + 1, len);
	path_out += len;
	*path_out = '\0';
	fprintf(stderr, "Path out: %s\n", path_out_base);

	*out_mount = mount;

	return strlen(root_name) ? PROC_PATH_PROXY_DIR : PROC_PATH_ROOT_DIR;
}

static int afuse_getattr(const char *path, struct stat *stbuf)
{
	int res;
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	int retval;
	mount_list_t *mount;
	BLOCK_SIGALRM;

	fprintf(stderr, "> GetAttr\n");

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;

		case PROC_PATH_ROOT_DIR:
			fprintf(stderr, "Getattr on: (%s) - %s\n", path, root_name);
			if(mount || strlen(root_name) == 0) {
				stbuf->st_mode    = S_IFDIR | 0700;
				stbuf->st_nlink   = 1;
				stbuf->st_uid     = getuid();
				stbuf->st_gid     = getgid();
				stbuf->st_size    = 0;
				stbuf->st_blksize = 0;
				stbuf->st_blocks  = 0;
				stbuf->st_atime   = 0;
				stbuf->st_mtime   = 0;
				stbuf->st_ctime   = 0;
				retval = 0;
			} else
				retval = -ENOENT;
			break;

		case PROC_PATH_PROXY_DIR:
			retval = get_retval(lstat(real_path, stbuf));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_readlink(const char *path, char *buf, size_t size)
{
	int res;
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	int retval;
	mount_list_t *mount;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOENT;
			break;
		case PROC_PATH_PROXY_DIR:
			res = readlink(real_path, buf, size - 1);
			if (res == -1)
			{
				retval = -errno;
				break;
			}
			buf[res] = '\0';
			retval = 0;
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_opendir(const char *path, struct fuse_file_info *fi)
{
	DIR *dp;
	char *root_name = alloca( strlen(path) );
	mount_list_t *mount;
	char *real_path = alloca( max_path_out_len(path) );
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = 0;
			break;
		case PROC_PATH_PROXY_DIR:
			dp = opendir(real_path);
			if (dp == NULL) {
				retval = -errno;
				break;
			}
			fi->fh = (unsigned long) dp;
			if(mount)
				dir_list_add(&mount->dir_list, dp);
			retval = 0;
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static inline DIR *get_dirp(struct fuse_file_info *fi)
{
	return (DIR *) (uintptr_t) fi->fh;
}

static int afuse_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
                       off_t offset, struct fuse_file_info *fi)
{
	DIR *dp = get_dirp(fi);
	struct dirent *de;
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount, *next;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;

		case PROC_PATH_ROOT_DIR:
			filler(buf, ".", NULL, 0);
			filler(buf, "..", NULL, 0);
			for(mount = mount_list; mount; mount = next)
			{
				next = mount->next;
				/* Check for dead mounts. */
				if (!check_mount(mount))
					do_umount(mount);
				else
					filler(buf, mount->root_name, NULL, 0);
			}
			mount = NULL;
			retval = 0;
			break;

		case PROC_PATH_PROXY_DIR:
			seekdir(dp, offset);
			while ((de = readdir(dp)) != NULL) {
				struct stat st;
				memset(&st, 0, sizeof(st));
				st.st_ino = de->d_ino;
				st.st_mode = de->d_type << 12;
				if (filler(buf, de->d_name, &st, telldir(dp)))
					break;
			}
			retval = 0;
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_releasedir(const char *path, struct fuse_file_info *fi)
{
	DIR *dp = get_dirp(fi);
	mount_list_t *mount;
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	int retval;

	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;

		case PROC_PATH_ROOT_DIR:
			retval = 0;
			break;

		case PROC_PATH_PROXY_DIR:
			if (mount)
				dir_list_remove(&mount->dir_list, dp);
			closedir(dp);
			retval = 0;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_mknod(const char *path, mode_t mode, dev_t rdev)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;
	fprintf(stderr, "> Mknod\n");

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;

		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;

		case PROC_PATH_PROXY_DIR:
			if (S_ISFIFO(mode))
				retval = get_retval(mkfifo(real_path, mode));
			else
				retval = get_retval(mknod(real_path, mode, rdev));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_mkdir(const char *path, mode_t mode)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	int retval;
	mount_list_t *mount;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(mkdir(real_path, mode));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_unlink(const char *path)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(unlink(real_path));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_rmdir(const char *path)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			if (!extract_root_name(path, root_name))
			{
				/* Unmount */
				if (mount->dir_list || mount->fd_list)
					retval = -EBUSY;
				else
				{
					do_umount(mount);
					mount = NULL;
					retval = 0;
				}
			} else
				retval = get_retval(rmdir(real_path));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_symlink(const char *from, const char *to)
{
	char *root_name_to = alloca( strlen(to) );
	char *real_to_path = alloca( max_path_out_len(to) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(to, real_to_path, root_name_to, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(symlink(from, real_to_path));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_rename(const char *from, const char *to)
{
	char *root_name_from = alloca( strlen(from) );
	char *root_name_to = alloca( strlen(to) );
	char *real_from_path = alloca( max_path_out_len(from) );
	char *real_to_path = alloca( max_path_out_len(to) );
	mount_list_t *mount_from, *mount_to = NULL;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(from, real_from_path, root_name_from, 0, &mount_from) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;

		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;

		case PROC_PATH_PROXY_DIR:
			switch( process_path(to, real_to_path, root_name_to, 0, &mount_to) )
			{
				case PROC_PATH_FAILED:
					retval = -ENXIO;
					break;

				case PROC_PATH_ROOT_DIR:
					retval = -ENOTSUP;
					break;

				case PROC_PATH_PROXY_DIR:
					retval = get_retval(rename(real_from_path, real_to_path));
					break;
			}
			break;
	}
	if (mount_to)
		update_auto_unmount(mount_to);
	if (mount_from && mount_from != mount_to)
		update_auto_unmount(mount_from);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_link(const char *from, const char *to)
{
	char *root_name_from = alloca( strlen(from) );
	char *root_name_to = alloca( strlen(to) );
	char *real_from_path = alloca( max_path_out_len(from) );
	char *real_to_path = alloca( max_path_out_len(to) );
	mount_list_t *mount_to = NULL, *mount_from;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(from, real_from_path, root_name_from, 0, &mount_from) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			switch( process_path(to, real_to_path, root_name_to, 0, &mount_to) )
			{
				case PROC_PATH_FAILED:
					retval = -ENXIO;
					break;
				case PROC_PATH_ROOT_DIR:
					retval = -ENOTSUP;
					break;
				case PROC_PATH_PROXY_DIR:
					retval = get_retval(link(real_from_path, real_to_path));
					break;
			}
			break;
	}
	if (mount_to)
		update_auto_unmount(mount_to);
	if (mount_from && mount_from != mount_to)
		update_auto_unmount(mount_from);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_chmod(const char *path, mode_t mode)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(chmod(real_path, mode));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_chown(const char *path, uid_t uid, gid_t gid)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(lchown(real_path, uid, gid));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_truncate(const char *path, off_t size)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(truncate(real_path, size));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}


static int afuse_utime(const char *path, struct utimbuf *buf)
{
	int res;
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(utime(real_path, buf));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}


static int afuse_open(const char *path, struct fuse_file_info *fi)
{
	int fd;
	char *root_name = alloca( strlen(path) );
	mount_list_t *mount;
	char *real_path = alloca( max_path_out_len(path) );
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOENT;
			break;
		case PROC_PATH_PROXY_DIR:
			fd = open(real_path, fi->flags);
			if (fd == -1) {
				retval = -errno;
				break;
			}

			fi->fh = fd;
			if(mount)
				fd_list_add(&mount->fd_list, fd);
			retval = 0;
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_read(const char *path, char *buf, size_t size, off_t offset,
                      struct fuse_file_info *fi)
{
	int res;

	(void)path;
	res = pread(fi->fh, buf, size, offset);
	if (res == -1)
		res = -errno;

	return res;
}

static int afuse_write(const char *path, const char *buf, size_t size,
                     off_t offset, struct fuse_file_info *fi)
{
	int res;

	(void) path;
	res = pwrite(fi->fh, buf, size, offset);
	if (res == -1)
		res = -errno;

	if(user_options.flush_writes)
		fsync(fi->fh);

	return res;
}


static int afuse_release(const char *path, struct fuse_file_info *fi)
{
	char *root_name = alloca( strlen(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	extract_root_name(path, root_name);
	mount = find_mount(root_name);
	retval = get_retval(close(fi->fh));

	if(mount)
	{
		fd_list_remove(&mount->fd_list, fi->fh);
		update_auto_unmount(mount);
	}

	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_fsync(const char *path, int isdatasync,
                       struct fuse_file_info *fi)
{
	int res;
	(void) path;

	#ifndef HAVE_FDATASYNC
	(void) isdatasync;
	#else
	if (isdatasync)
		res = fdatasync(fi->fh);
	else
	#endif
		res = fsync(fi->fh);
	return get_retval(res);
}

#if FUSE_VERSION >= 25
static int afuse_access(const char *path, int mask)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(access(real_path, mask));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_ftruncate(const char *path, off_t size,
                           struct fuse_file_info *fi)
{
	(void) path;
	return get_retval(ftruncate(fi->fh, size));
}

static int afuse_create(const char *path, mode_t mode, struct fuse_file_info *fi)
{
	int fd;
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			fd = open(real_path, fi->flags, mode);
			if (fd == -1)
			{
				retval = -errno;
				break;
			}
			fi->fh = fd;
			retval = 0;
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_fgetattr(const char *path, struct stat *stbuf,
                          struct fuse_file_info *fi)
{
	(void) path;

	return get_retval(fstat(fi->fh, stbuf));
}
#endif


#if FUSE_VERSION >= 25
static int afuse_statfs(const char *path, struct statvfs *stbuf)
#else
static int afuse_statfs(const char *path, struct statfs *stbuf)
#endif
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;

		case PROC_PATH_ROOT_DIR:
#if FUSE_VERSION >= 25
			stbuf->f_namemax = 0x7fffffff;
			stbuf->f_frsize  = 512;
#else
			stbuf->f_namelen = 0x7fffffff;
#endif
			stbuf->f_bsize   = 1024;
			stbuf->f_blocks  = 0;
			stbuf->f_bfree   = 0;
			stbuf->f_bavail  = 0;
			stbuf->f_files   = 0;
			stbuf->f_ffree   = 0;
			retval = 0;
			break;

		case PROC_PATH_PROXY_DIR:
			retval = get_retval(statvfs(real_path, stbuf));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

void afuse_destroy(void *p)
{
	shutdown();
}

#ifdef HAVE_SETXATTR
/* xattr operations are optional and can safely be left unimplemented */
static int afuse_setxattr(const char *path, const char *name, const char *value,
						  size_t size, int flags)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOENT;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(lsetxattr(real_path, name, value, size, flags));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_getxattr(const char *path, const char *name, char *value,
						  size_t size)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(lgetxattr(real_path, name, value, size));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_listxattr(const char *path, char *list, size_t size)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 1, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(llistxattr(real_path, list, size));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}

static int afuse_removexattr(const char *path, const char *name)
{
	char *root_name = alloca( strlen(path) );
	char *real_path = alloca( max_path_out_len(path) );
	mount_list_t *mount;
	int retval;
	BLOCK_SIGALRM;

	switch( process_path(path, real_path, root_name, 0, &mount) )
	{
		case PROC_PATH_FAILED:
			retval = -ENXIO;
			break;
		case PROC_PATH_ROOT_DIR:
			retval = -ENOTSUP;
			break;
		case PROC_PATH_PROXY_DIR:
			retval = get_retval(lremovexattr(real_path, name));
			break;
	}
	if (mount)
		update_auto_unmount(mount);
	UNBLOCK_SIGALRM;
	return retval;
}
#endif /* HAVE_SETXATTR */

static struct fuse_operations afuse_oper = {
	.getattr     = afuse_getattr,
	.readlink    = afuse_readlink,
	.opendir     = afuse_opendir,
	.readdir     = afuse_readdir,
	.releasedir  = afuse_releasedir,
	.mknod       = afuse_mknod,
	.mkdir       = afuse_mkdir,
	.symlink     = afuse_symlink,
	.unlink      = afuse_unlink,
	.rmdir       = afuse_rmdir,
	.rename      = afuse_rename,
	.link        = afuse_link,
	.chmod       = afuse_chmod,
	.chown       = afuse_chown,
	.truncate    = afuse_truncate,
	.utime       = afuse_utime,
	.open        = afuse_open,
	.read        = afuse_read,
	.write       = afuse_write,
	.release     = afuse_release,
	.fsync       = afuse_fsync,
	.statfs      = afuse_statfs,
#if FUSE_VERSION >= 25
	.access      = afuse_access,
	.create      = afuse_create,
	.ftruncate   = afuse_ftruncate,
	.fgetattr    = afuse_fgetattr,
#endif
	.destroy     = afuse_destroy,
#ifdef HAVE_SETXATTR
	.setxattr    = afuse_setxattr,
	.getxattr    = afuse_getxattr,
	.listxattr   = afuse_listxattr,
	.removexattr = afuse_removexattr,
#endif
};


enum {
	KEY_HELP,
	KEY_FLUSHWRITES
};

#define AFUSE_OPT(t, p, v) { t, offsetof(struct user_options_t, p), v }

static struct fuse_opt afuse_opts[] = {
	AFUSE_OPT("mount_template=%s", mount_command_template, 0),
	AFUSE_OPT("unmount_template=%s", unmount_command_template, 0),

	AFUSE_OPT("timeout=%Lu", auto_unmount_delay, 0),

	FUSE_OPT_KEY("flushwrites",     KEY_FLUSHWRITES),
	FUSE_OPT_KEY("-h",     KEY_HELP),
	FUSE_OPT_KEY("--help", KEY_HELP),

	FUSE_OPT_END
};

static void usage(const char *progname)
{
	fprintf(stderr,
"Usage: %s mountpoint [options]\n"
"\n"
"    -o opt,[opt...]        mount options\n"
"    -h   --help            print help\n"
"    -V   --version         print FUSE version information\n"
"\n"
"afuse options:\n"
"    -o mount_template=CMD    template for CMD to execute to mount (*)\n"
"    -o unmount_template=CMD  template for CMD to execute to unmount (*) (**)\n"
"    -o timeout=TIMEOUT       automatically unmount after TIMEOUT microseconds\n"
"    -o flushwrites           flushes data to disk for all file writes\n"
"\n\n"
" (*) - When executed, %%r and %%m are expanded in templates to the root\n"
"       directory name for the new mount point, and the actual directory to\n"
"       mount onto respectively to mount onto. Both templates are REQUIRED.\n"
"\n"
" (**) - The unmount command must perform a lazy unmount operation. E.g. the\n"
"        -u -z options to fusermount, or -l for regular mount.\n"
"\n", progname);
}

static int afuse_opt_proc(void *data, const char *arg, int key,
                          struct fuse_args *outargs)
{
	(void) arg;

	switch(key)
	{
		case KEY_HELP:
			usage(outargs->argv[0]);
			fuse_opt_add_arg(outargs, "-ho");
			fuse_main(outargs->argc, outargs->argv, &afuse_oper);
			exit(1);

		case KEY_FLUSHWRITES:
			user_options.flush_writes = true;
			return 0;

		default:
			return 1;
	}
}

int main(int argc, char *argv[])
{
	struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
	char *temp_dir_name = my_malloc(strlen(TMP_DIR_TEMPLATE));
	strcpy(temp_dir_name, TMP_DIR_TEMPLATE);

	if(fuse_opt_parse(&args, &user_options, afuse_opts, afuse_opt_proc) == -1)
		return 1;

	// !!FIXME!! force single-threading for now as datastructures are not locked
	fuse_opt_add_arg(&args, "-s");

	auto_unmount_ph_init(&auto_unmount_ph);

	/**
	 * Install the SIGALRM signal handler.
	 */
	{
		struct sigaction act;
		act.sa_handler = &handle_auto_unmount_timer;
		sigemptyset(&act.sa_mask);
		act.sa_flags = 0;
		while (sigaction(SIGALRM, &act, NULL) == -1 && errno == EINTR)
			continue;
	}

	// Check for required parameters
	if(!user_options.mount_command_template || !user_options.unmount_command_template) {
		fprintf(stderr, "(Un)Mount command templates missing.\n\n");
		usage(argv[0]);
		fuse_opt_add_arg(&args, "-ho");
		fuse_main(args.argc, args.argv, &afuse_oper);

		return 1;
	}

	if( !(mount_point_directory = mkdtemp(temp_dir_name)) ) {
		fprintf(stderr, "Failed to create temporary mount point dir.\n");
		return 1;
	}

	{
		struct stat buf;
		if (lstat(mount_point_directory, &buf) == -1) {
			fprintf(stderr, "Failed to stat temporary mount point dir.\n");
			return 1;
		}
		mount_point_dev = buf.st_dev;
	}

	umask(0);


	// !!FIXME!! death by signal doesn't unmount fs
	return fuse_main(args.argc, args.argv, &afuse_oper);
}

/*
  Local Variables:
  c-basic-offset: 4
  indent-tabs-mode: t
  End:
 */