utmp: support non-rootfs configuration

Having a rootfs is not a necessary condition for monitoring utmp, since
/var or /var/run can just be remounted inside the container instead. We
should rely on the other two conditions already in place to decide
whether to monitor the utmp file:

 - the container was started with 'lxc-start', which indicates that it
   has a real init process and is expected to write to a utmp file

 - support for CAP_SYS_BOOT was not found in the kernel, which would
   otherwise supersede utmp monitoring

Signed-off-by: David Ward <david.ward@ll.mit.edu>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/src/lxc/utmp.c b/src/lxc/utmp.c
index b6469b09a92e09b778cd251bf057c805655d2333..a7b9b525de05a876947fc9bf7fb320f3a8512183 100644 (file)
--- a/src/lxc/utmp.c
+++ b/src/lxc/utmp.c
@@ -233,10 +233,6 @@ int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
        char path2[MAXPATHLEN];
        int fd, wd;
        struct lxc_utmp *utmp_data;
-       struct lxc_conf *conf = handler->conf;
-
-       if (!conf->rootfs.path)
-               return 0;
 
        /* We set up a watch for the /var/run directory. We're only interested
         * in utmp at the moment, but want to watch for delete and create