fuse: sync with upstream

Cherry-picked following commits from
git://fuse.git.sourceforge.net/gitroot/fuse/fuse
form 555d6b50..acc5c79d interval:

  commit 1193a39c0869a3608f22472735bcffdcccb6b2a5
  Author: Reuben Hawkins <reubenhwk@gmail.com>

      cleaning up warnings

  commit dba9185999dfa35161d4c810735df0ab3fde5104
  Author: Laszlo Papp <ext-laszlo.papp@nokia.com>

      Check the 'mtablock' for negative value

  commit e63a9d8ee6529c9d15a87745276f45c9bdad3961
  Author: Miklos Szeredi <miklos@szeredi.hu>

      fusermount: clean up do_mount() function

  commit 81fee822a098a3e26969401fc486f136465f96f0
  Author: Laszlo Papp <ext-laszlo.papp@nokia.com>

      Eliminate the unused value

  commit 60eb44ee5eb2756465610b215968f176f4aaac6e
  Author: Laszlo Papp <ext-laszlo.papp@nokia.com>

      Fix resource leaks in fusermount

  commit d6bec4020fddd4dd67248789a1af600580f2cbda
  Author: Miklos Szeredi <mszeredi@suse.cz>

      In case of failure to add to /etc/mtab don't umount.

  commit 1e7607ff89c65b005f69e27aeb1649d624099873
  Author: Miklos Szeredi <mszeredi@suse.cz>

      fusermount: chdir to / before performing mount/umount

  commit 2fcbc2a5a94983813c533c015134c6974f8ee636
  Author: Miklos Szeredi <miklos@szeredi.hu>

      fusermount: don't save/restore cwd

  commit bd99f9cf24e16643752b02fb4fa7b48f2124ab4e
  Author: Miklos Szeredi <miklos@szeredi.hu>

      Fix check for read-only fs in mtab update

Nb.:
- not picked changes that implement and enforce mount/umount
  mechanisms based on newer util-linux features (umount --fake
  and --no-canonicalize)
- not picked fusermount "auto-unmount" feature

Change-Id: Ib9498516184336e77ec047e5414125332d0a4292
BUG: 762389
Signed-off-by: Csaba Henk <csaba@redhat.com>
Reviewed-on: http://review.gluster.com/3343
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

3 files changed, 62 insertions, 48 deletions

diff --git a/contrib/fuse-lib/mount-common.c b/contrib/fuse-lib/mount-common.c
index 7411e56c89b..fd6cce44e3d 100644
--- a/contrib/fuse-lib/mount-common.c
+++ b/contrib/fuse-lib/mount-common.c
@@ -20,10 +20,11 @@
  * - there are some other minor things
  *
  * For changes that were made later and syncs with upstream,
- * see the commit log.
+ * see the commit log and per-function comments.
  */
 
 #ifndef __NetBSD__
+/* FUSE: cherry-picked bd99f9cf */
 static int
 mtab_needs_update (const char *mnt)
 {
@@ -47,11 +48,22 @@ mtab_needs_update (const char *mnt)
                 if (errno == ENOENT)
                         return 0;
         } else {
+                uid_t ruid;
+                int err;
+
                 if (S_ISLNK (stbuf.st_mode))
                         return 0;
 
+                ruid = getuid ();
+                if (ruid != 0)
+                        setreuid (0, -1);
+
                 res = access (_PATH_MOUNTED, W_OK);
-                if (res == -1 && errno == EROFS)
+                err = (res == -1) ? errno : 0;
+                if (ruid != 0)
+                        setreuid (ruid, -1);
+
+                if (err == EROFS)
                         return 0;
         }
 
@@ -61,6 +73,7 @@ mtab_needs_update (const char *mnt)
 #define mtab_needs_update(x) 1
 #endif /* __NetBSD__ */
 
+/* FUSE: called add_mount_legacy(); R.I.P. as of cbd3a2a8 */
 int
 fuse_mnt_add_mount (const char *progname, const char *fsname,
                     const char *mnt, const char *type, const char *opts)
@@ -194,6 +207,11 @@ fuse_mnt_resolve_path (const char *progname, const char *orig)
         return dst;
 }
 
+/* FUSE: to support some changes that were reverted since
+ * then, it was split in two (fuse_mnt_umount() and
+ * exec_umount()); however the actual code is same as here
+ * since 0197ce40
+ */
 int
 fuse_mnt_umount (const char *progname, const char *abs_mnt,
                  const char *rel_mnt, int lazy)
diff --git a/contrib/fuse-lib/mount.c b/contrib/fuse-lib/mount.c
index 8787064fc04..f02a835b3a8 100644
--- a/contrib/fuse-lib/mount.c
+++ b/contrib/fuse-lib/mount.c
@@ -18,6 +18,7 @@
 #define FUSE_DEVFD_ENV "_FUSE_DEVFD"
 
 
+/* FUSE: function is called fuse_kern_unmount() */
 void
 gf_fuse_unmount (const char *mountpoint, int fd)
 {
diff --git a/contrib/fuse-util/fusermount.c b/contrib/fuse-util/fusermount.c
index 4e7e4f9501c..9a89525718d 100644
--- a/contrib/fuse-util/fusermount.c
+++ b/contrib/fuse-util/fusermount.c
@@ -116,8 +116,16 @@ static int lock_umount(void)
 
 static void unlock_umount(int mtablock)
 {
-	lockf(mtablock, F_ULOCK, 0);
-	close(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,
@@ -240,7 +248,7 @@ static int check_is_mount_child(void *p)
 	}
 
 	count = 0;
-	while ((entp = getmntent(fp)) != NULL)
+	while (getmntent(fp) != NULL)
 		count++;
 	endmntent(fp);
 
@@ -327,7 +335,7 @@ static int check_is_mount(const char *last, const char *mnt)
 	return 0;
 }
 
-static int chdir_to_parent(char *copy, const char **lastp, int *currdir_fd)
+static int chdir_to_parent(char *copy, const char **lastp)
 {
 	char *tmp;
 	const char *parent;
@@ -352,14 +360,6 @@ static int chdir_to_parent(char *copy, const char **lastp, int *currdir_fd)
 		parent = "/";
 	}
 
-	*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(parent);
 	if (res == -1) {
 		fprintf(stderr, "%s: failed to chdir to %s: %s\n",
@@ -384,7 +384,6 @@ static int chdir_to_parent(char *copy, const char **lastp, int *currdir_fd)
 
 static int unmount_fuse_locked(const char *mnt, int quiet, int lazy)
 {
-	int currdir_fd = -1;
 	char *copy;
 	const char *last;
 	int res;
@@ -401,7 +400,7 @@ static int unmount_fuse_locked(const char *mnt, int quiet, int lazy)
 		return -1;
 	}
 
-	res = chdir_to_parent(copy, &last, &currdir_fd);
+	res = chdir_to_parent(copy, &last);
 	if (res == -1)
 		goto out;
 
@@ -413,10 +412,6 @@ static int unmount_fuse_locked(const char *mnt, int quiet, int lazy)
 
 out:
 	free(copy);
-	if (currdir_fd != -1) {
-		fchdir(currdir_fd);
-		close(currdir_fd);
-	}
 
 	return res;
 }
@@ -825,15 +820,14 @@ 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);
@@ -876,8 +870,7 @@ 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;
@@ -895,13 +888,6 @@ 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,
@@ -1057,7 +1043,6 @@ static int mount_fuse(const char *mnt, const char *opts, char *devfd)
 	char *source = NULL;
 	char *mnt_opts = NULL;
 	const char *real_mnt = mnt;
-	int currdir_fd = -1;
 	int mountpoint_fd = -1;
 
 	fd = devfd ? check_fuse_device(devfd, &dev) : open_fuse_device(&dev);
@@ -1071,15 +1056,13 @@ static int mount_fuse(const char *mnt, const char *opts, char *devfd)
 		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,
@@ -1088,33 +1071,38 @@ static int mount_fuse(const char *mnt, const char *opts, char *devfd)
 	} 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)
@@ -1253,6 +1241,13 @@ 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);