4 files changed, 527 insertions, 127 deletions

diff --git a/contrib/fuse-util/Makefile.am b/contrib/fuse-util/Makefile.am
index 42609a6883d..abbc10eb6d9 100644
--- a/contrib/fuse-util/Makefile.am
+++ b/contrib/fuse-util/Makefile.am
@@ -1,9 +1,11 @@
 bin_PROGRAMS = fusermount-glusterfs
 
-fusermount_glusterfs_SOURCES = fusermount.c $(CONTRIBDIR)/fuse-lib/mount.c
-noinst_HEADERS = mount_util.h
+fusermount_glusterfs_SOURCES = fusermount.c mount_util.c $(CONTRIBDIR)/fuse-lib/mount-common.c
+noinst_HEADERS = $(CONTRIBDIR)/fuse-include/mount_util.h
 
-AM_CFLAGS = -Wall -D_FILE_OFFSET_BITS=64 -DFUSE_UTIL $(GF_CFLAGS)
+AM_CPPFLAGS = $(GF_CPPFLAGS) -DFUSE_UTIL -I$(CONTRIBDIR)/fuse-include -I$(CONTRIBDIR)/fuse-lib
+
+AM_CFLAGS = -Wall $(GF_CFLAGS)
 
 install-exec-hook:
 	-chown root $(DESTDIR)$(bindir)/fusermount-glusterfs
diff --git a/contrib/fuse-util/fusermount.c b/contrib/fuse-util/fusermount.c
index c3ecc86cc44..ff743f75a21 100644
--- a/contrib/fuse-util/fusermount.c
+++ b/contrib/fuse-util/fusermount.c
@@ -10,6 +10,11 @@
 #include <config.h>
 
 #include "mount_util.h"
+
+#ifndef HAVE_UMOUNT2
+#include "mount-gluster-compat.h"
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -19,14 +24,24 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <pwd.h>
+#include <limits.h>
+#if !defined(__NetBSD__) && !defined(GF_DARWIN_HOST_OS)
 #include <mntent.h>
+#endif /* __NetBSD__ */
 #include <sys/wait.h>
 #include <sys/stat.h>
-#include <sys/mount.h>
+#ifdef HAVE_SET_FSID
 #include <sys/fsuid.h>
+#endif
+#ifdef GF_DARWIN_HOST_OS
+#include <sys/param.h>
+#endif
+#include <sys/mount.h>
 #include <sys/socket.h>
 #include <sys/utsname.h>
+#include <sched.h>
 
+#define FUSE_DEVFD_ENV		"_FUSE_DEVFD"
 #define FUSE_COMMFD_ENV		"_FUSE_COMMFD"
 
 #define FUSE_DEV_OLD "/proc/fs/fuse/dev"
@@ -37,6 +52,12 @@
 #ifndef MS_DIRSYNC
 #define MS_DIRSYNC 128
 #endif
+#ifndef MS_REC
+#define MS_REC 16384
+#endif
+#ifndef MS_PRIVATE
+#define MS_PRIVATE (1<<18)
+#endif
 
 static const char *progname;
 
@@ -54,97 +75,378 @@ static const char *get_user_name(void)
 	}
 }
 
+#ifdef HAVE_SET_FSID
 static uid_t oldfsuid;
 static gid_t oldfsgid;
+#endif
 
 static void drop_privs(void)
 {
 	if (getuid() != 0) {
+#ifdef HAVE_SET_FSID
 		oldfsuid = setfsuid(getuid());
 		oldfsgid = setfsgid(getgid());
+#else
+		fprintf(stderr, "%s: Implement alternative setfsuid/gid \n", progname);
+#endif
 	}
 }
 
 static void restore_privs(void)
 {
 	if (getuid() != 0) {
+#ifdef HAVE_SET_FSID
 		setfsuid(oldfsuid);
 		setfsgid(oldfsgid);
+#else
+		fprintf(stderr, "%s: Implement alternative setfsuid/gid \n", progname);
+#endif
 	}
 }
 
 #ifndef IGNORE_MTAB
+/*
+ * Make sure that /etc/mtab is checked and updated atomically
+ */
+static int lock_umount(void)
+{
+	const char *mtab_lock = _PATH_MOUNTED ".fuselock";
+	int mtablock;
+	int res;
+	struct stat mtab_stat;
+
+	/* /etc/mtab could be a symlink to /proc/mounts */
+	if (lstat(_PATH_MOUNTED, &mtab_stat) == 0 && S_ISLNK(mtab_stat.st_mode))
+		return -1;
+
+	mtablock = open(mtab_lock, O_RDWR | O_CREAT, 0600);
+	if (mtablock == -1) {
+		fprintf(stderr, "%s: unable to open fuse lock file: %s\n",
+			progname, strerror(errno));
+		return -1;
+	}
+	res = lockf(mtablock, F_LOCK, 0);
+	if (res < 0) {
+		fprintf(stderr, "%s: error getting lock: %s\n", progname,
+			strerror(errno));
+		close(mtablock);
+		return -1;
+	}
+
+	return mtablock;
+}
+
+static void unlock_umount(int mtablock)
+{
+	if (mtablock >= 0) {
+		int res;
+
+		res = lockf(mtablock, F_ULOCK, 0);
+		if (res < 0) {
+			fprintf(stderr, "%s: error releasing lock: %s\n",
+				progname, strerror(errno));
+		}
+		close(mtablock);
+	}
+}
+
 static int add_mount(const char *source, const char *mnt, const char *type,
 		     const char *opts)
 {
 	return fuse_mnt_add_mount(progname, source, mnt, type, opts);
 }
 
-static int unmount_fuse(const char *mnt, int quiet, int lazy)
+static int may_unmount(const char *mnt, int quiet)
 {
-	if (getuid() != 0) {
-		struct mntent *entp;
-		FILE *fp;
-		const char *user = NULL;
-		char uidstr[32];
-		unsigned uidlen = 0;
-		int found;
-		const char *mtab = _PATH_MOUNTED;
-
-		user = get_user_name();
-		if (user == NULL)
-			return -1;
+	struct mntent *entp;
+	FILE *fp;
+	const char *user = NULL;
+	char uidstr[32];
+	unsigned uidlen = 0;
+	int found;
+	const char *mtab = _PATH_MOUNTED;
 
-		fp = setmntent(mtab, "r");
-		if (fp == NULL) {
-			fprintf(stderr,
-				"%s: failed to open %s: %s\n", progname, mtab,
-				strerror(errno));
-			return -1;
-		}
+	user = get_user_name();
+	if (user == NULL)
+		return -1;
 
-		uidlen = sprintf(uidstr, "%u", getuid());
-
-		found = 0;
-		while ((entp = getmntent(fp)) != NULL) {
-			if (!found && strcmp(entp->mnt_dir, mnt) == 0 &&
-			    (strcmp(entp->mnt_type, "fuse") == 0 ||
-			     strcmp(entp->mnt_type, "fuseblk") == 0 ||
-			     strncmp(entp->mnt_type, "fuse.", 5) == 0 ||
-			     strncmp(entp->mnt_type, "fuseblk.", 8) == 0)) {
-				char *p = strstr(entp->mnt_opts, "user=");
-				if (p &&
-				    (p == entp->mnt_opts || *(p-1) == ',') &&
-				    strcmp(p + 5, user) == 0) {
-					found = 1;
-					break;
-				}
-				/* /etc/mtab is a link pointing to
-				   /proc/mounts: */
-				else if ((p =
-					  strstr(entp->mnt_opts, "user_id=")) &&
-					 (p == entp->mnt_opts ||
-					  *(p-1) == ',') &&
-					 strncmp(p + 8, uidstr, uidlen) == 0 &&
-					 (*(p+8+uidlen) == ',' ||
-					  *(p+8+uidlen) == '\0')) {
-					found = 1;
-					break;
-				}
+	fp = setmntent(mtab, "r");
+	if (fp == NULL) {
+		fprintf(stderr, "%s: failed to open %s: %s\n", progname, mtab,
+			strerror(errno));
+		return -1;
+	}
+
+	uidlen = sprintf(uidstr, "%u", getuid());
+
+	found = 0;
+	while ((entp = getmntent(fp)) != NULL) {
+		if (!found && strcmp(entp->mnt_dir, mnt) == 0 &&
+		    (strcmp(entp->mnt_type, "fuse") == 0 ||
+		     strcmp(entp->mnt_type, "fuseblk") == 0 ||
+		     strncmp(entp->mnt_type, "fuse.", 5) == 0 ||
+		     strncmp(entp->mnt_type, "fuseblk.", 8) == 0)) {
+			char *p = strstr(entp->mnt_opts, "user=");
+			if (p &&
+			    (p == entp->mnt_opts || *(p-1) == ',') &&
+			    strcmp(p + 5, user) == 0) {
+				found = 1;
+				break;
+			}
+			/* /etc/mtab is a link pointing to
+			   /proc/mounts: */
+			else if ((p =
+				  strstr(entp->mnt_opts, "user_id=")) &&
+				 (p == entp->mnt_opts ||
+				  *(p-1) == ',') &&
+				 strncmp(p + 8, uidstr, uidlen) == 0 &&
+				 (*(p+8+uidlen) == ',' ||
+				  *(p+8+uidlen) == '\0')) {
+				found = 1;
+				break;
 			}
 		}
-		endmntent(fp);
+	}
+	endmntent(fp);
 
-		if (!found) {
-			if (!quiet)
-				fprintf(stderr,
-					"%s: entry for %s not found in %s\n",
-					progname, mnt, mtab);
-			return -1;
+	if (!found) {
+		if (!quiet)
+			fprintf(stderr,
+				"%s: entry for %s not found in %s\n",
+				progname, mnt, mtab);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Check whether the file specified in "fusermount -u" is really a
+ * mountpoint and not a symlink.  This is necessary otherwise the user
+ * could move the mountpoint away and replace it with a symlink
+ * pointing to an arbitrary mount, thereby tricking fusermount into
+ * unmounting that (umount(2) will follow symlinks).
+ *
+ * This is the child process running in a separate mount namespace, so
+ * we don't mess with the global namespace and if the process is
+ * killed for any reason, mounts are automatically cleaned up.
+ *
+ * First make sure nothing is propagated back into the parent
+ * namespace by marking all mounts "private".
+ *
+ * Then bind mount parent onto a stable base where the user can't move
+ * it around.
+ *
+ * Finally check /proc/mounts for an entry matching the requested
+ * mountpoint.  If it's found then we are OK, and the user can't move
+ * it around within the parent directory as rename() will return
+ * EBUSY.  Be careful to ignore any mounts that existed before the
+ * bind.
+ */
+static int check_is_mount_child(void *p)
+{
+	const char **a = p;
+	const char *last = a[0];
+	const char *mnt = a[1];
+	int res;
+	const char *procmounts = "/proc/mounts";
+	int found;
+	FILE *fp;
+	struct mntent *entp;
+	int count;
+
+	res = mount("", "/", "", MS_PRIVATE | MS_REC, NULL);
+	if (res == -1) {
+		fprintf(stderr, "%s: failed to mark mounts private: %s\n",
+			progname, strerror(errno));
+		return 1;
+	}
+
+	fp = setmntent(procmounts, "r");
+	if (fp == NULL) {
+		fprintf(stderr, "%s: failed to open %s: %s\n", progname,
+			procmounts, strerror(errno));
+		return 1;
+	}
+
+	count = 0;
+	while (getmntent(fp) != NULL)
+		count++;
+	endmntent(fp);
+
+	fp = setmntent(procmounts, "r");
+	if (fp == NULL) {
+		fprintf(stderr, "%s: failed to open %s: %s\n", progname,
+			procmounts, strerror(errno));
+		return 1;
+	}
+
+	res = mount(".", "/", "", MS_BIND | MS_REC, NULL);
+	if (res == -1) {
+		fprintf(stderr, "%s: failed to bind parent to /: %s\n",
+			progname, strerror(errno));
+		return 1;
+	}
+
+	found = 0;
+	while ((entp = getmntent(fp)) != NULL) {
+		if (count > 0) {
+			count--;
+			continue;
+		}
+		if (entp->mnt_dir[0] == '/' &&
+		    strcmp(entp->mnt_dir + 1, last) == 0) {
+			found = 1;
+			break;
 		}
 	}
+	endmntent(fp);
+
+	if (!found) {
+		fprintf(stderr, "%s: %s not mounted\n", progname, mnt);
+		return 1;
+	}
 
-	return fuse_mnt_umount(progname, mnt, lazy);
+	return 0;
+}
+
+static pid_t clone_newns(void *a)
+{
+	char buf[131072];
+	char *stack = buf + (sizeof(buf) / 2 - ((size_t) buf & 15));
+
+#ifdef __ia64__
+	extern int __clone2(int (*fn)(void *),
+			    void *child_stack_base, size_t stack_size,
+			    int flags, void *arg, pid_t *ptid,
+			    void *tls, pid_t *ctid);
+
+	return __clone2(check_is_mount_child, stack, sizeof(buf) / 2,
+			CLONE_NEWNS, a, NULL, NULL, NULL);
+#else
+	return clone(check_is_mount_child, stack, CLONE_NEWNS, a);
+#endif
+}
+
+static int check_is_mount(const char *last, const char *mnt)
+{
+	pid_t pid, p;
+	int status;
+	const char *a[2] = { last, mnt };
+
+	pid = clone_newns((void *) a);
+	if (pid == (pid_t) -1) {
+		fprintf(stderr, "%s: failed to clone namespace: %s\n",
+			progname, strerror(errno));
+		return -1;
+	}
+	p = waitpid(pid, &status, __WCLONE);
+	if (p == (pid_t) -1) {
+		fprintf(stderr, "%s: waitpid failed: %s\n",
+			progname, strerror(errno));
+		return -1;
+	}
+	if (!WIFEXITED(status)) {
+		fprintf(stderr, "%s: child terminated abnormally (status %i)\n",
+			progname, status);
+		return -1;
+	}
+	if (WEXITSTATUS(status) != 0)
+		return -1;
+
+	return 0;
+}
+
+static int chdir_to_parent(char *copy, const char **lastp)
+{
+	char *tmp;
+	const char *parent;
+	char buf[65536];
+	int res;
+
+	tmp = strrchr(copy, '/');
+	if (tmp == NULL || tmp[1] == '\0') {
+		fprintf(stderr, "%s: internal error: invalid abs path: <%s>\n",
+			progname, copy);
+		return -1;
+	}
+	if (tmp != copy) {
+		*tmp = '\0';
+		parent = copy;
+		*lastp = tmp + 1;
+	} else if (tmp[1] != '\0') {
+		*lastp = tmp + 1;
+		parent = "/";
+	} else {
+		*lastp = ".";
+		parent = "/";
+	}
+
+	res = chdir(parent);
+	if (res == -1) {
+		fprintf(stderr, "%s: failed to chdir to %s: %s\n",
+			progname, parent, strerror(errno));
+		return -1;
+	}
+
+	if (getcwd(buf, sizeof(buf)) == NULL) {
+		fprintf(stderr, "%s: failed to obtain current directory: %s\n",
+			progname, strerror(errno));
+		return -1;
+	}
+	if (strcmp(buf, parent) != 0) {
+		fprintf(stderr, "%s: mountpoint moved (%s -> %s)\n", progname,
+			parent, buf);
+		return -1;
+
+	}
+
+	return 0;
+}
+
+static int unmount_fuse_locked(const char *mnt, int quiet, int lazy)
+{
+	char *copy;
+	const char *last;
+	int res;
+
+	if (getuid() != 0) {
+		res = may_unmount(mnt, quiet);
+		if (res == -1)
+			return -1;
+	}
+
+	copy = strdup(mnt);
+	if (copy == NULL) {
+		fprintf(stderr, "%s: failed to allocate memory\n", progname);
+		return -1;
+	}
+
+	res = chdir_to_parent(copy, &last);
+	if (res == -1)
+		goto out;
+
+	res = check_is_mount(last, mnt);
+	if (res == -1)
+		goto out;
+
+	res = fuse_mnt_umount(progname, mnt, last, lazy);
+
+out:
+	free(copy);
+
+	return res;
+}
+
+static int unmount_fuse(const char *mnt, int quiet, int lazy)
+{
+	int res;
+	int mtablock = lock_umount();
+
+	res = unmount_fuse_locked(mnt, quiet, lazy);
+	unlock_umount(mtablock);
+
+	return res;
 }
 
 static int count_fuse_fs(void)
@@ -186,7 +488,7 @@ static int add_mount(const char *source, const char *mnt, const char *type,
 
 static int unmount_fuse(const char *mnt, int quiet, int lazy)
 {
-	return fuse_mnt_umount(progname, mnt, lazy);
+	return fuse_mnt_umount(progname, mnt, mnt, lazy);
 }
 #endif /* IGNORE_MTAB */
 
@@ -218,20 +520,22 @@ static void parse_line(char *line, int linenum)
 
 static void read_conf(void)
 {
+	int  len;
 	FILE *fp = fopen(FUSE_CONF, "r");
 	if (fp != NULL) {
 		int linenum = 1;
 		char line[256];
 		int isnewline = 1;
 		while (fgets(line, sizeof(line), fp) != NULL) {
+			len = strlen (line);
 			if (isnewline) {
-				if (line[strlen(line)-1] == '\n') {
+				if (len && line[len-1] == '\n') {
 					strip_line(line);
 					parse_line(line, linenum);
 				} else {
 					isnewline = 0;
 				}
-			} else if(line[strlen(line)-1] == '\n') {
+			} else if (len && line[len-1] == '\n') {
 				fprintf(stderr, "%s: reading %s: line %i too long\n", progname, FUSE_CONF, linenum);
 
 				isnewline = 1;
@@ -326,7 +630,7 @@ static int add_option(char **optsp, const char *opt, unsigned expand)
 static int get_mnt_opts(int flags, char *opts, char **mnt_optsp)
 {
 	int i;
-	int l;
+	size_t l;
 
 	if (!(flags & MS_RDONLY) && add_option(mnt_optsp, "rw", 0) == -1)
 		return -1;
@@ -341,7 +645,7 @@ static int get_mnt_opts(int flags, char *opts, char **mnt_optsp)
 		return -1;
 	/* remove comma from end of opts*/
 	l = strlen(*mnt_optsp);
-	if ((*mnt_optsp)[l-1] == ',')
+	if (l && (*mnt_optsp)[l-1] == ',')
 		(*mnt_optsp)[l-1] = '\0';
 	if (getuid() != 0) {
 		const char *user = get_user_name();
@@ -366,18 +670,26 @@ static int opt_eq(const char *s, unsigned len, const char *opt)
 static int get_string_opt(const char *s, unsigned len, const char *opt,
 			  char **val)
 {
+	int i;
 	unsigned opt_len = strlen(opt);
+	char *d;
 
-	if (*val)
-		free(*val);
+	free(*val);
 	*val = (char *) malloc(len - opt_len + 1);
 	if (!*val) {
 		fprintf(stderr, "%s: failed to allocate memory\n", progname);
 		return 0;
 	}
 
-	memcpy(*val, s + opt_len, len - opt_len);
-	(*val)[len - opt_len] = '\0';
+	d = *val;
+	s += opt_len;
+	len -= opt_len;
+	for (i = 0; i < len; i++) {
+		if (s[i] == '\\' && i + 1 < len)
+			i++;
+		*d++ = s[i];
+	}
+	*d = '\0';
 	return 1;
 }
 
@@ -408,7 +720,12 @@ static int do_mount(const char *mnt, char **typep, mode_t rootmode,
 		unsigned len;
 		const char *fsname_str = "fsname=";
 		const char *subtype_str = "subtype=";
-		for (len = 0; s[len] && s[len] != ','; len++);
+		for (len = 0; s[len]; len++) {
+			if (s[len] == '\\' && s[len + 1])
+				len++;
+			else if (s[len] == ',')
+				break;
+		}
 		if (begins_with(s, fsname_str)) {
 			if (!get_string_opt(s, len, fsname_str, &fsname))
 				goto err;
@@ -526,15 +843,14 @@ static int do_mount(const char *mnt, char **typep, mode_t rootmode,
 			fprintf(stderr, "%s: mount failed: %s\n", progname,
 				strerror(errno_save));
 		goto err;
-	} else {
-		*sourcep = source;
-		*typep = type;
-		*mnt_optsp = mnt_opts;
 	}
+	*sourcep = source;
+	*typep = type;
+	*mnt_optsp = mnt_opts;
 	free(fsname);
 	free(optbuf);
 
-	return res;
+	return 0;
 
 err:
 	free(fsname);
@@ -577,8 +893,7 @@ static int check_version(const char *dev)
 	return 0;
 }
 
-static int check_perm(const char **mntp, struct stat *stbuf, int *currdir_fd,
-		      int *mountpoint_fd)
+static int check_perm(const char **mntp, struct stat *stbuf, int *mountpoint_fd)
 {
 	int res;
 	const char *mnt = *mntp;
@@ -596,13 +911,6 @@ static int check_perm(const char **mntp, struct stat *stbuf, int *currdir_fd,
 		return 0;
 
 	if (S_ISDIR(stbuf->st_mode)) {
-		*currdir_fd = open(".", O_RDONLY);
-		if (*currdir_fd == -1) {
-			fprintf(stderr,
-				"%s: failed to open current directory: %s\n",
-				progname, strerror(errno));
-			return -1;
-		}
 		res = chdir(mnt);
 		if (res == -1) {
 			fprintf(stderr,
@@ -719,8 +1027,36 @@ static int open_fuse_device(char **devp)
 	return -1;
 }
 
+static int check_fuse_device(char *devfd, char **devp)
+{
+	int res;
+	char *devlink;
 
-static int mount_fuse(const char *mnt, const char *opts)
+	res = asprintf(&devlink, "/proc/self/fd/%s", devfd);
+	if (res == -1) {
+		fprintf(stderr, "%s: failed to allocate memory\n", progname);
+		return -1;
+	}
+
+	*devp = (char *) calloc(1, PATH_MAX + 1);
+	if (!*devp) {
+		fprintf(stderr, "%s: failed to allocate memory\n", progname);
+		free(devlink);
+		return -1;
+	}
+
+	res = readlink (devlink, *devp, PATH_MAX);
+	free (devlink);
+	if (res == -1) {
+		fprintf(stderr, "%s: specified fuse fd is invalid\n",
+			progname);
+		return -1;
+	}
+
+	return atoi(devfd);
+}
+
+static int mount_fuse(const char *mnt, const char *opts, char *devfd)
 {
 	int res;
 	int fd;
@@ -730,10 +1066,9 @@ static int mount_fuse(const char *mnt, const char *opts)
 	char *source = NULL;
 	char *mnt_opts = NULL;
 	const char *real_mnt = mnt;
-	int currdir_fd = -1;
 	int mountpoint_fd = -1;
 
-	fd = open_fuse_device(&dev);
+	fd = devfd ? check_fuse_device(devfd, &dev) : open_fuse_device(&dev);
 	if (fd == -1)
 		return -1;
 
@@ -744,15 +1079,13 @@ static int mount_fuse(const char *mnt, const char *opts)
 		int mount_count = count_fuse_fs();
 		if (mount_count >= mount_max) {
 			fprintf(stderr, "%s: too many FUSE filesystems mounted; mount_max=N can be set in /etc/fuse.conf\n", progname);
-			close(fd);
-			return -1;
+			goto fail_close_fd;
 		}
 	}
 
 	res = check_version(dev);
 	if (res != -1) {
-		res = check_perm(&real_mnt, &stbuf, &currdir_fd,
-				 &mountpoint_fd);
+		res = check_perm(&real_mnt, &stbuf, &mountpoint_fd);
 		restore_privs();
 		if (res != -1)
 			res = do_mount(real_mnt, &type, stbuf.st_mode & S_IFMT,
@@ -761,33 +1094,38 @@ static int mount_fuse(const char *mnt, const char *opts)
 	} else
 		restore_privs();
 
-	if (currdir_fd != -1) {
-		fchdir(currdir_fd);
-		close(currdir_fd);
-	}
 	if (mountpoint_fd != -1)
 		close(mountpoint_fd);
 
+	if (res == -1)
+		goto fail_close_fd;
+
+	res = chdir("/");
 	if (res == -1) {
-		close(fd);
-		return -1;
+		fprintf(stderr, "%s: failed to chdir to '/'\n", progname);
+		goto fail_close_fd;
 	}
 
 	if (geteuid() == 0) {
 		res = add_mount(source, mnt, type, mnt_opts);
 		if (res == -1) {
-			umount2(mnt, 2); /* lazy umount */
-			close(fd);
-			return -1;
+			/* Can't clean up mount in a non-racy way */
+			goto fail_close_fd;
 		}
 	}
 
+out_free:
 	free(source);
 	free(type);
 	free(mnt_opts);
 	free(dev);
 
 	return fd;
+
+fail_close_fd:
+	close(fd);
+	fd = -1;
+	goto out_free;
 }
 
 static int send_fd(int sock_fd, int fd)
@@ -857,6 +1195,7 @@ int main(int argc, char *argv[])
 	static int unmount = 0;
 	static int lazy = 0;
 	static int quiet = 0;
+	char *devfd;
 	char *commfd;
 	int cfd;
 	const char *opts = "";
@@ -925,6 +1264,13 @@ int main(int argc, char *argv[])
 
 	drop_privs();
 	mnt = fuse_mnt_resolve_path(progname, origmnt);
+	if (mnt != NULL) {
+		res = chdir("/");
+		if (res == -1) {
+			fprintf(stderr, "%s: failed to chdir to '/'\n", progname);
+			exit(1);
+		}
+	}
 	restore_privs();
 	if (mnt == NULL)
 		exit(1);
@@ -945,21 +1291,26 @@ int main(int argc, char *argv[])
 		return 0;
 	}
 
-	commfd = getenv(FUSE_COMMFD_ENV);
-	if (commfd == NULL) {
-		fprintf(stderr, "%s: old style mounting not supported\n",
-			progname);
-		exit(1);
+	devfd = getenv(FUSE_DEVFD_ENV);
+	if (devfd == NULL) {
+		commfd = getenv(FUSE_COMMFD_ENV);
+		if (commfd == NULL) {
+			fprintf(stderr, "%s: old style mounting not supported\n",
+				progname);
+			exit(1);
+		}
 	}
 
-	fd = mount_fuse(mnt, opts);
+	fd = mount_fuse(mnt, opts, devfd);
 	if (fd == -1)
 		exit(1);
 
-	cfd = atoi(commfd);
-	res = send_fd(cfd, fd);
-	if (res == -1)
-		exit(1);
+	if (devfd == NULL) {
+		cfd = atoi(commfd);
+		res = send_fd(cfd, fd);
+		if (res == -1)
+			exit(1);
+	}
 
 	return 0;
 }
diff --git a/contrib/fuse-util/mount_util.c b/contrib/fuse-util/mount_util.c
new file mode 100644
index 00000000000..911b84445e9
--- /dev/null
+++ b/contrib/fuse-util/mount_util.c
@@ -0,0 +1,64 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
+
+  This program can be distributed under the terms of the GNU LGPLv2.
+  See the file COPYING.LIB.
+*/
+
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int fuse_mnt_check_empty(const char *progname, const char *mnt,
+			 mode_t rootmode, off_t rootsize)
+{
+	int isempty = 1;
+
+	if (S_ISDIR(rootmode)) {
+		struct dirent *ent;
+		DIR *dp = opendir(mnt);
+		if (dp == NULL) {
+			fprintf(stderr,
+				"%s: failed to open mountpoint for reading: %s\n",
+				progname, strerror(errno));
+			return -1;
+		}
+		while ((ent = readdir(dp)) != NULL) {
+			if (strcmp(ent->d_name, ".") != 0 &&
+			    strcmp(ent->d_name, "..") != 0) {
+				isempty = 0;
+				break;
+			}
+		}
+		closedir(dp);
+	} else if (rootsize)
+		isempty = 0;
+
+	if (!isempty) {
+		fprintf(stderr, "%s: mountpoint is not empty\n", progname);
+		fprintf(stderr, "%s: if you are sure this is safe, use the 'nonempty' mount option\n", progname);
+		return -1;
+	}
+	return 0;
+}
+
+int fuse_mnt_check_fuseblk(void)
+{
+	char buf[256];
+	FILE *f = fopen("/proc/filesystems", "r");
+	if (!f)
+		return 1;
+
+	while (fgets(buf, sizeof(buf), f))
+		if (strstr(buf, "fuseblk\n")) {
+			fclose(f);
+			return 1;
+		}
+
+	fclose(f);
+	return 0;
+}
diff --git a/contrib/fuse-util/mount_util.h b/contrib/fuse-util/mount_util.h
deleted file mode 100644
index cf54d9d0d02..00000000000
--- a/contrib/fuse-util/mount_util.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/*
-  FUSE: Filesystem in Userspace
-  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
-
-  This program can be distributed under the terms of the GNU LGPLv2.
-  See the file COPYING.LIB.
-*/
-
-#include <sys/types.h>
-
-int fuse_mnt_add_mount(const char *progname, const char *fsname,
-		       const char *mnt, const char *type, const char *opts);
-int fuse_mnt_umount(const char *progname, const char *mnt, int lazy);
-char *fuse_mnt_resolve_path(const char *progname, const char *orig);
-int fuse_mnt_check_empty(const char *progname, const char *mnt,
-			 mode_t rootmode, off_t rootsize);
-int fuse_mnt_check_fuseblk(void);