From 0e2489974b91e4728d544fe2aa08c2a1c9deb365 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Fri, 24 Jan 2014 10:20:14 +0000 Subject: [PATCH] fuse: In mount-local-run, test if root filesystem has been mounted (RHBZ#1057504). It is never normally valid to use the mount-local* APIs when you haven't mounted some filesystems in the libguestfs namespace. If you try it, it results in some odd errors. The mount-local-run call is successful, but subsequent operations fail: $ mkdir -p /tmp/mnt $ guestfish -x -N fs mount-local /tmp/mnt : mount-local-run libguestfs: error: lstat: lstat_stub: you must call 'mount' first to mount the root filesystem libguestfs: error: lstat: lstat_stub: you must call 'mount' first to mount the root filesystem With this commit, the mount-local-run call gives an error: libguestfs: error: you must call 'guestfs_mount' first to mount a filesystem on '/'. Note: '/tmp/mnt' is still mounted. Use 'guestunmount /tmp/mnt' to clean up. The error is implemented by calling guestfs_exists (g, "/") which has the side effect of running the NEED_ROOT macro in the daemon. (There is no simple equivalent of NEED_ROOT on the library side.) --- src/fuse.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/fuse.c b/src/fuse.c index dd4f139e29..caf8719e9a 100644 --- a/src/fuse.c +++ b/src/fuse.c @@ -1028,6 +1028,18 @@ guestfs__mount_local_run (guestfs_h *g) return -1; } + /* Test if root is mounted. We do this by using a side-effect of + * guestfs_exists (which is that it calls NEED_ROOT). + */ + guestfs_push_error_handler (g, NULL, NULL); + r = guestfs_exists (g, "/"); + guestfs_pop_error_handler (g); + if (r == -1) { + error (g, _("you must call 'guestfs_mount' first to mount a filesystem on '/'.\nNote: '%s' is still mounted. Use 'guestunmount %s' to clean up."), + g->localmountpoint, g->localmountpoint); + return -1; + } + debug (g, "%s: entering fuse_loop", __func__); /* Enter the main loop. */