path: root/logger/src/hook_fusefs/hookfs.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
  Copyright (C) 2011       Sebastian Pipping <sebastian@pipping.org>
  Copyright (C) 2011       Alexander Bersenev <bay@hackerdom.ru>

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

#define PACKAGE_NAME "hookfs"
#define PACKAGE_VERSION "0.1"

#define FUSE_USE_VERSION 26

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#define _GNU_SOURCE

#include <fuse.h>
#include <ulockmgr.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <sys/time.h>
#include <stddef.h>
#include <assert.h>
#include <sys/mman.h>
#ifdef HAVE_SETXATTR
#include <sys/xattr.h>
#endif
#include <sys/socket.h>
#include <sys/un.h>
#include <pthread.h>


#define MIN(a, b)  (((a) < (b)) ? (a) : (b))

#define MAXSOCKETPATHLEN 108

struct hookfs_config {
     int argv_debug;
};


pthread_mutex_t socketblock = PTHREAD_MUTEX_INITIALIZER;

int mountpoint_fd = -1;
char *mountpoint = NULL;
FILE * log_file = NULL;
int log_socket=-1;
struct hookfs_config config;

/*
 * Prints a string escaping spaces and '\'
 * Does not check input variables
*/
static void __print_escaped(FILE *fh ,const char *s){
	for(;(*s)!=0; s++) {
		if(*s==' ')
		  fprintf(fh,"\\ ");
		else if(*s==',')
		  fprintf(fh,"\\,");
		else if(*s=='\r')
		  fprintf(fh,"\\r");
		else if(*s=='\n')
		  fprintf(fh,"\\n");
		else if(*s=='\\')
		  fprintf(fh,"\\\\");
		else
		  fprintf(fh,"%c", *s);
	}
}

/*
 * This is here because launching of a task is very slow without it
 */
static int is_file_excluded(const char *filename) {
  if(strcmp(filename,"/etc/ld.so.preload")==0)
	return 1;
  if(strcmp(filename,"/etc/ld.so.cache")==0)
	return 1;
  if(strcmp(filename,"/usr/lib64/locale/locale-archive")==0)
	return 1;
  if(strcmp(filename,"/usr/lib64/locale")==0)
	return 1;
  
  return 0;
}


static void raw_log_event(const char *event_type, const char *filename, char *result,int err, pid_t pid) {
  if(is_file_excluded(filename)) return;


  fprintf(log_file,"%lld ",(unsigned long long)time(NULL));

  __print_escaped(log_file, event_type);
  fprintf(log_file," ");
  __print_escaped(log_file, filename);
  
  fprintf(log_file," %d ", pid);
  if(strcmp(result,"ERR")==0)
	fprintf(log_file,"%s/%d",result,err);
  else
	fprintf(log_file,"%s",result);
  fprintf(log_file,"\n");
  fflush(log_file);

}

/*
 * Format of log string: time event file flags result parents
*/
static void log_event(const char *event_type, const char *filename, char *result,int err, pid_t pid) {
  pthread_mutex_lock( &socketblock );
  raw_log_event(event_type,filename,result,err,pid);
  pthread_mutex_unlock( &socketblock );
}

/*
 * Ack a python part about an event
 * Returns 1 if access is allowed and 0 if denied
*/
static int is_event_allowed(const char *event_type,const char *filename, pid_t pid) {
  // sending asking log_event
  if(is_file_excluded(filename)) return 1;
  //return 1;
  pthread_mutex_lock( &socketblock );
  
  raw_log_event(event_type,filename,"ASKING",0,pid);
  char answer[8];

  fscanf(log_file,"%7s",answer);
  fflush(log_file); // yes, it is here too
  pthread_mutex_unlock( &socketblock );
  
  if(strcmp(answer,"ALLOW")==0)
	return 1;
  else if(strcmp(answer,"DENY")==0)
	return 0;
  else
	fprintf(stderr,"Protocol error, text should be ALLOW or DENY, got: %s",answer);
  return 0;
}

static char * malloc_relative_path(const char *path) {
	int len = strlen(path);
	char * buf = malloc(1 + len + 1);
	if (! buf) {
		return NULL;
	}

	strcpy(buf, ".");
	strcpy(buf + 1, path);
	return buf;
}

static void give_to_creator_fd(int fd) {
	struct fuse_context * context = fuse_get_context();
	fchown(fd, context->uid, context->gid);
}

static void give_to_creator_path(const char *path) {
	struct fuse_context * context = fuse_get_context();
	lchown(path, context->uid, context->gid);
}

static int hookfs_getattr(const char *path, struct stat *stbuf)
{
  	struct fuse_context * context = fuse_get_context();

	if(! is_event_allowed("stat",path,context->pid)) {
	  errno=2; // not found
	  log_event("stat",path,"DENIED",errno,context->pid);

	  return -errno;
	}

	
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = lstat(rel_path, stbuf);
	free(rel_path);
		
	if (res == -1) {
   		log_event("stat",path,"ERR",errno,context->pid);
		return -errno;
	}
	log_event("stat",path,"OK",errno,context->pid);

	return 0;
}

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

  	struct fuse_context * context = fuse_get_context();
	if(! is_event_allowed("stat",path,context->pid)) {
	  errno=2; // not found
	  log_event("stat",path,"DENIED",errno,context->pid);

	  return -errno;
	}

	
	res = fstat(fi->fh, stbuf);
	
	if (res == -1) {
   		log_event("stat",path,"ERR",errno,context->pid);
		return -errno;
	}
	log_event("stat",path,"OK",errno,context->pid);
	
	return 0;
}

static int hookfs_access(const char *path, int mask)
{
 	struct fuse_context * context = fuse_get_context();

	if(! is_event_allowed("stat",path,context->pid)) {
	  errno=2; // not found
	  log_event("stat",path,"DENIED",errno,context->pid);

	  return -errno;
	}

	
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = access(rel_path, mask);
	free(rel_path);
	
	if (res == -1) {
   		log_event("stat",path,"ERR",errno,context->pid);
		return -errno;
	}
	log_event("stat",path,"OK",errno,context->pid);
	
	return 0;
}

static int hookfs_readlink(const char *path, char *buf, size_t size)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = readlink(rel_path, buf, size - 1);
	free(rel_path);

	if (res == -1)
		return -errno;

	buf[res] = '\0';
	return 0;
}

struct hookfs_dirp {
	DIR *dp;
	struct dirent *entry;
	off_t offset;
};

static int hookfs_opendir(const char *path, struct fuse_file_info *fi)
{
	struct hookfs_dirp *d = malloc(sizeof(struct hookfs_dirp));
	if (d == NULL)
		return -ENOMEM;

	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	d->dp = opendir(rel_path);
	free(rel_path);
	if (d->dp == NULL) {
		free(d);
		return -errno;
	}
	d->offset = 0;
	d->entry = NULL;

	fi->fh = (unsigned long) d;
	return 0;
}

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

static int hookfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
		       off_t offset, struct fuse_file_info *fi)
{
	struct hookfs_dirp *d = get_dirp(fi);

	(void) path;
	if (offset != d->offset) {
		seekdir(d->dp, offset);
		d->entry = NULL;
		d->offset = offset;
	}
	while (1) {
		struct stat st;
		off_t nextoff;

		if (!d->entry) {
			d->entry = readdir(d->dp);
			if (!d->entry)
				break;
		}

		memset(&st, 0, sizeof(st));
		st.st_ino = d->entry->d_ino;
		st.st_mode = d->entry->d_type << 12;
		nextoff = telldir(d->dp);
		if (filler(buf, d->entry->d_name, &st, nextoff))
			break;

		d->entry = NULL;
		d->offset = nextoff;
	}

	return 0;
}

static int hookfs_releasedir(const char *path, struct fuse_file_info *fi)
{
	struct hookfs_dirp *d = get_dirp(fi);
	(void) path;
	closedir(d->dp);
	free(d);
	return 0;
}

static int hookfs_mknod(const char *path, mode_t mode, dev_t rdev)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res;
	if (S_ISFIFO(mode))
		res = mkfifo(rel_path, mode);
	else
		res = mknod(rel_path, mode, rdev);
	if (res == 0)
		give_to_creator_path(rel_path);
	free(rel_path);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_mkdir(const char *path, mode_t mode)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = mkdir(rel_path, mode);
	if (res == 0)
		give_to_creator_path(rel_path);
	free(rel_path);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_unlink(const char *path)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = unlink(rel_path);
	free(rel_path);

	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_rmdir(const char *path)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = rmdir(rel_path);
	free(rel_path);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_symlink(const char *from, const char *to)
{
	char * rel_to = malloc_relative_path(to);
	if (! rel_to) {
		return -errno;
	}

	int res = symlink(from, rel_to);
	if (res == 0)
		give_to_creator_path(rel_to);
	free(rel_to);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_rename(const char *from, const char *to)
{
	char * rel_from = malloc_relative_path(from);
	if (! rel_from) {
		return -errno;
	}
	char * rel_to = malloc_relative_path(to);
	if (! rel_to) {
		free(rel_from);
		return -errno;
	}

	int res = rename(rel_from, rel_to);
	//NOTIFY(post_rename, from, to, res);
	free(rel_from);
	free(rel_to);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_link(const char *from, const char *to)
{
	char * rel_from = malloc_relative_path(from);
	if (! rel_from) {
		return -errno;
	}
	char * rel_to = malloc_relative_path(to);
	if (! rel_to) {
		free(rel_from);
		return -errno;
	}

	int res = link(rel_from, rel_to);
	free(rel_from);
	if (res == 0)
		give_to_creator_path(rel_to);
	free(rel_to);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_chmod(const char *path, mode_t mode)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = chmod(rel_path, mode);
	free(rel_path);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_chown(const char *path, uid_t uid, gid_t gid)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = lchown(rel_path, uid, gid);
	free(rel_path);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_truncate(const char *path, off_t size)
{
	struct fuse_context * context = fuse_get_context();

	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = truncate(rel_path, size);
	free(rel_path);

	if (res == -1) {
  		log_event("write",path,"ERR",errno,context->pid);
		return -errno;
	}
	log_event("write",path,"OK",errno,context->pid);
	
	return 0;
}

static int hookfs_ftruncate(const char *path, off_t size,
			 struct fuse_file_info *fi)
{
	int res;

	struct fuse_context * context = fuse_get_context();

	res = ftruncate(fi->fh, size);

	if (res == -1) {
  		log_event("write",path,"ERR",errno,context->pid);
		return -errno;
	}
	log_event("write",path,"OK",errno,context->pid);

	return 0;
}

static int hookfs_utimens(const char *path, const struct timespec ts[2])
{
	int res;
	struct timeval tv[2];
	char * rel_path = NULL;

	tv[0].tv_sec = ts[0].tv_sec;
	tv[0].tv_usec = ts[0].tv_nsec / 1000;
	tv[1].tv_sec = ts[1].tv_sec;
	tv[1].tv_usec = ts[1].tv_nsec / 1000;

	rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	res = utimes(rel_path, tv);
	free(rel_path);
	if (res == -1)
		return -errno;

	return 0;
}

static int writing_flags(mode_t mode) {
	if (((mode & O_WRONLY) == O_WRONLY)
			|| ((mode & O_RDWR) == O_RDWR)
			|| ((mode & O_CREAT) == O_CREAT)) {
		return 1;
	}
	return 0;
}

static int open_safely(const char *rel_path, int flags, mode_t mode) {
	int fd = -1;
	if (writing_flags(flags)) {
		fd = open(rel_path, flags | O_CREAT | O_EXCL, mode);
		if (fd == -1) {
			/* Try again with original flags */
			fd = open(rel_path, flags, mode);
		} else {
			give_to_creator_fd(fd);
		}
	} else {
		fd = open(rel_path, flags, mode);
	}
	return fd;
}

static int hookfs_create(const char *path, mode_t mode, struct fuse_file_info *fi)
{
	struct fuse_context * context = fuse_get_context();
  
	if(! is_event_allowed("create",path,context->pid)) {
	  errno=2; // not found
	  log_event("create",path,"DENIED",errno,context->pid);

	  return -errno;
	}

	char * rel_path = malloc_relative_path(path);
	
	if (! rel_path) {
		return -errno;
	}

	int fd = open_safely(rel_path, fi->flags, mode);
	free(rel_path);

	if (fd == -1) {
		log_event("create",path,"ERR",errno,context->pid);
		return -errno;
	} 
	log_event("create",path,"OK",errno,context->pid);

	fi->fh = fd;
	return 0;
}

static int hookfs_open(const char *path, struct fuse_file_info *fi)
{
	int fd;
	char * rel_path = NULL;

	struct fuse_context * context = fuse_get_context();

	if(! is_event_allowed("open",path,context->pid)) {
	  errno=2; // not found
	  log_event("open",path,"DENIED",errno,context->pid);

	  return -errno;
	}
	
	rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	fd = open_safely(rel_path, fi->flags, 0000);
	free(rel_path);

	if (fd == -1) {
		log_event("open",path,"ERR",errno,context->pid);
		return -errno;
	}
	
	log_event("open",path,"OK",errno,context->pid);
	fi->fh = fd;
	return 0;
}

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

	struct fuse_context * context = fuse_get_context();
	
	res = pread(fi->fh, buf, size, offset);
	if (res == -1) {
		log_event("read",path,"ERR",errno,context->pid);
		res = -errno;
	}

	log_event("read",path,"OK",errno,context->pid);
	return res;
}

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

	struct fuse_context * context = fuse_get_context();

	res = pwrite(fi->fh, buf, size, offset);
	if (res == -1) {
  		log_event("write",path,"ERR",errno,context->pid);
		res = -errno;
	}

	log_event("write",path,"OK",errno,context->pid);

	return res;
}

static int hookfs_statfs(const char *path, struct statvfs *stbuf)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = statvfs(rel_path, stbuf);
	free(rel_path);
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_flush(const char *path, struct fuse_file_info *fi)
{
	int res;

	(void) path;
	/* This is called from every close on an open file, so call the
	   close on the underlying filesystem.	But since flush may be
	   called multiple times for an open file, this must not really
	   close the file.  This is important if used on a network
	   filesystem like NFS which flush the data/metadata on close() */
	res = close(dup(fi->fh));
	if (res == -1)
		return -errno;

	return 0;
}

static int hookfs_release(const char *path, struct fuse_file_info *fi)
{
	(void) path;

	//int res = 
	close(fi->fh);

	return 0;
}

static int hookfs_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);
	if (res == -1)
		return -errno;

	return 0;
}

#ifdef HAVE_SETXATTR
/* xattr operations are optional and can safely be left unimplemented */
static int hookfs_setxattr(const char *path, const char *name, const char *value,
			size_t size, int flags)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = lsetxattr(rel_path, name, value, size, flags);
	free(rel_path);
	if (res == -1)
		return -errno;
	return 0;
}

static int hookfs_getxattr(const char *path, const char *name, char *value,
			size_t size)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = lgetxattr(rel_path, name, value, size);
	free(rel_path);
	if (res == -1)
		return -errno;
	return res;
}

static int hookfs_listxattr(const char *path, char *list, size_t size)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = llistxattr(rel_path, list, size);
	free(rel_path);
	if (res == -1)
		return -errno;
	return res;
}

static int hookfs_removexattr(const char *path, const char *name)
{
	char * rel_path = malloc_relative_path(path);
	if (! rel_path) {
		return -errno;
	}

	int res = lremovexattr(rel_path, name);
	free(rel_path);
	if (res == -1)
		return -errno;
	return 0;
}
#endif /* HAVE_SETXATTR */

static int hookfs_lock(const char *path, struct fuse_file_info *fi, int cmd,
		    struct flock *lock)
{
	(void) path;

	return ulockmgr_op(fi->fh, cmd, lock, &fi->lock_owner,
			   sizeof(fi->lock_owner));
}

static void * hookfs_init(struct fuse_conn_info *conn) {
	int res = fchdir(mountpoint_fd);
	assert(! res);

	close(mountpoint_fd);
	mountpoint_fd = -1;

	return NULL;
}

static void hookfs_destroy() {
	fflush(log_file);
}

static struct fuse_operations hookfs_oper = {
	.getattr	= hookfs_getattr,
	.fgetattr	= hookfs_fgetattr,
	.access		= hookfs_access,
	.readlink	= hookfs_readlink,
	.opendir	= hookfs_opendir,
	.readdir	= hookfs_readdir,
	.releasedir	= hookfs_releasedir,
	.mknod		= hookfs_mknod,
	.mkdir		= hookfs_mkdir,
	.symlink	= hookfs_symlink,
	.unlink		= hookfs_unlink,
	.rmdir		= hookfs_rmdir,
	.rename		= hookfs_rename,
	.link		= hookfs_link,
	.chmod		= hookfs_chmod,
	.chown		= hookfs_chown,
	.truncate	= hookfs_truncate,
	.ftruncate	= hookfs_ftruncate,
	.utimens	= hookfs_utimens,
	.create		= hookfs_create,
	.open		= hookfs_open,
	.read		= hookfs_read,
	.write		= hookfs_write,
	.statfs		= hookfs_statfs,
	.flush		= hookfs_flush,
	.release	= hookfs_release,
	.fsync		= hookfs_fsync,
#ifdef HAVE_SETXATTR
	.setxattr	= hookfs_setxattr,
	.getxattr	= hookfs_getxattr,
	.listxattr	= hookfs_listxattr,
	.removexattr	= hookfs_removexattr,
#endif
	.lock		= hookfs_lock,
	.init		= hookfs_init,
	.destroy	= hookfs_destroy,

	.flag_nullpath_ok = 1,
};

static int try_chdir_to_mountpoint(int argc, char *argv[]) {
	struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
	int err = -1;

	err = fuse_parse_cmdline(&args, &mountpoint, NULL, NULL);
	fuse_opt_free_args(&args);
	if (err || ! mountpoint) {
		fprintf(stderr, "Mountpoint missing\n");
		return 0;
	}

	mountpoint_fd = open(mountpoint, O_DIRECTORY|O_RDONLY);
	if (err || (mountpoint_fd == -1)) {
		fprintf(stderr, "Could not open \"%s\" as a directory.\n", mountpoint);
		return 0;
	}

	fprintf(stderr, "Switching workdir to mountpoint \"%s\"...\n", mountpoint);
	return 1;
}

void default_config(struct hookfs_config * config) {
	config->argv_debug = 0;
}

enum {
	 KEY_HELP,
	 KEY_VERSION,
};

#define HOOKFS_OPT(t, p, v) { t, offsetof(struct hookfs_config, p), v }

static struct fuse_opt hookfs_opts[] = {
	HOOKFS_OPT("--argv-debug", argv_debug, 1),

	FUSE_OPT_KEY("-V", KEY_VERSION),
	FUSE_OPT_KEY("--version", KEY_VERSION),
	FUSE_OPT_KEY("-h", KEY_HELP),
	FUSE_OPT_KEY("--help", KEY_HELP),
	FUSE_OPT_END
};

void debug_argv(int argc, char *argv[], const struct hookfs_config * config) {
	if (! config->argv_debug) {
		return;
	}

	for (int i = 0; i < argc; i++) {
		fprintf(stderr, "[%d] '%s'\n", i, argv[i]);
	}
}

static int hookfs_handle_opt(void *data, const char *arg, int key, struct fuse_args *outargs) {
	struct hookfs_config * config = (struct hookfs_config *)data;

	switch (key) {
	case KEY_HELP:
			fuse_opt_add_arg(outargs, "-ho");
			debug_argv(outargs->argc, outargs->argv, config);

			fprintf(stderr,
					 "usage: %s mountpoint [options]\n"
					 "\n"
					 "%s options:\n"
					 "    --argv-debug           enable argv debugging\n"
					 "\n"
					 "general options:\n"
					 "    -o opt,[opt...]        mount options\n"
					 "    -h   --help            print help\n"
					 "    -V   --version         print version\n"
					 "\n"
					 , outargs->argv[0], PACKAGE_NAME);
			fuse_main(outargs->argc, outargs->argv, &hookfs_oper, NULL);
			exit(1);

	case KEY_VERSION:
			fuse_opt_add_arg(outargs, "--version");
			debug_argv(outargs->argc, outargs->argv, config);

			fprintf(stderr, "%s version %s\n", PACKAGE_NAME, PACKAGE_VERSION);
			fuse_main(outargs->argc, outargs->argv, &hookfs_oper, NULL);
			exit(0);
	}
	return 1;
}

int main(int argc, char *argv[]) {
  struct fuse_args args = FUSE_ARGS_INIT(argc, argv);

  default_config(&config);

  fuse_opt_parse(&args, &config, hookfs_opts, hookfs_handle_opt);

  fuse_opt_add_arg(&args, "-o" "nonempty");  /* to allow shadowing */
  fuse_opt_add_arg(&args, "-o" "use_ino");  /* to keep hardlinks working */
  fuse_opt_add_arg(&args, "-o" "default_permissions");  /* to enable access checks */

  debug_argv(args.argc, args.argv, &config);

  char *log_socket_name=getenv("LOG_SOCKET");
  if(log_socket_name==NULL) {
	  fprintf(stderr,"Using stderr as output for logs "
			  "because the LOG_SOCKET environment variable isn't defined.\n");
	  log_file=stderr;
  } else {
	if(strlen(log_socket_name)>=MAXSOCKETPATHLEN) {
	  fprintf(stderr,"Unable to create a unix-socket %s: socket name is too long,exiting\n", log_socket_name);
	  return 1;
	}

	log_socket=socket(AF_UNIX, SOCK_STREAM, 0);
	if(log_socket==-1) {
	  fprintf(stderr,"Unable to create a unix-socket %s: %s\n", log_socket_name, strerror(errno));
	  return 1;
	}
	
	struct sockaddr_un serveraddr;
	memset(&serveraddr, 0, sizeof(serveraddr));
	serveraddr.sun_family = AF_UNIX;
	strcpy(serveraddr.sun_path, log_socket_name);
	
	int ret=connect(log_socket, (struct sockaddr *)&serveraddr, SUN_LEN(&serveraddr));
	if(ret==-1) {
	  fprintf(stderr,"Unable to connect a unix-socket: %s\n", strerror(errno));
	  return 1;
	}
	
	log_file=fdopen(log_socket,"a+");
	
	if(log_file==NULL) {
	  fprintf(stderr,"Unable to open a socket for a steam writing: %s\n", strerror(errno));
	  exit(1);
	}
  }
  
  if (! try_chdir_to_mountpoint(args.argc, args.argv)) {
	  return 1;
  }

  umask(0);
  int res = fuse_main(args.argc, args.argv, &hookfs_oper, NULL);
  fflush(log_file);
  fclose(log_file);
  return res;
}