[CRIU] [PATCH] mount: resolve parent mount of symbolic link correctly

[Andrew Vagin]

On Tue, Jul 26, 2016 at 04:15:35PM +0300, Pavel Emelyanov wrote:
> On 07/26/2016 01:42 AM, Andrew Vagin wrote:
> > On Mon, Jul 25, 2016 at 02:26:01PM +0000, Katerina Koukiou wrote:
> >> When using --root option in criu dump, when the mountpoint passed
> >> contains a symbolic link, criu does not resolve its parent correctly.
> >> e.g when passing --root /run/rootfs, dump finishes successfully;
> >> but when /var/run/rootfs is passed, where /var/run is symbolic link to
> >> /run it exits with error "New root and old root are the same".
> >>
> >> Signed-off-by: Katerina Koukiou <k.koukiou at gmail.com>
> >> ---
> >>  criu/mount.c | 10 +++++++++-
> >>  1 file changed, 9 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/criu/mount.c b/criu/mount.c
> >> index 7c280c0..0cd83af 100644
> >> --- a/criu/mount.c
> >> +++ b/criu/mount.c
> >> @@ -3420,6 +3420,8 @@ int prepare_mnt_ns(void)
> >>  			return -1;
> >>  	} else {
> >>  		struct mount_info *mi;
> >> +		char *ret;
> >> +		char path[PATH_MAX + 1];
> > 
> > PATH_MAX is enough, it includes '\0'
> >>  
> >>  		/*
> >>  		 * The whole tree of mountpoints is to be moved into one
> >> @@ -3428,8 +3430,14 @@ int prepare_mnt_ns(void)
> >>  		 * with a single umount call later.
> >>  		 */
> >>  
> >> +		ret = realpath(opts.root, path);
> > 
> > realpath returns a string, but a type of ret is int.
> 
> No, there's new char *ret in this block :)

Sorry, I haven't noticed this. Thanks.
> 
> >> +		if (!ret) {
> >> +			pr_err("Unable to find real path for %s\n", opts.root);
> >> +			return -1;
> >> +		}
> >> +
> >>  		/* moving a mount residing under a shared mount is invalid. */
> >> -		mi = mount_resolve_path(ns.mnt.mntinfo_tree, opts.root);
> >> +		mi = mount_resolve_path(ns.mnt.mntinfo_tree, path);
> >>  		if (mi == NULL) {
> >>  			pr_err("Unable to find mount point for %s\n", opts.root);
> >>  			return -1;
> >> -- 
> >> 2.7.3
> >>
> >> _______________________________________________
> >> CRIU mailing list
> >> CRIU at openvz.org
> >> https://lists.openvz.org/mailman/listinfo/criu
> > _______________________________________________
> > CRIU mailing list
> > CRIU at openvz.org
> > https://lists.openvz.org/mailman/listinfo/criu
> > .
> > 
>