Use container's proc to setup the utmp watching

The <rootfs>/var/run/utmp is located in:

/proc/<containerinit>/root/var/run/utmp, let's use it.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/src/lxc/utmp.c b/src/lxc/utmp.c
index dca9d726de90acecded845a140f179c663f2d213..e6249cec2f6647bd9960f22cc095faad5f2de14a 100644 (file)
--- a/src/lxc/utmp.c
+++ b/src/lxc/utmp.c
@@ -82,8 +82,10 @@ static int utmp_handler(int fd, void *data, struct lxc_epoll_descr *descr)
 
        struct lxc_utmp *utmp_data = (struct lxc_utmp *)data;
 
-       /* we're monitoring a directory. ie->name is not included in sizeof(struct inotify_event)
-        * if we don't read it all at once, read gives us EINVAL, so we read and cast to struct ie
+       /*
+        * we're monitoring a directory. ie->name is not included in
+        * sizeof(struct inotify_event) if we don't read it all at once,
+        * read gives us EINVAL, so we read and cast to struct ie
         */
        char buffer[MAXPATHLEN];
 
@@ -100,7 +102,13 @@ static int utmp_handler(int fd, void *data, struct lxc_epoll_descr *descr)
        ie = (struct inotify_event *)buffer;
 
        if (ie->len <= 0) {
-               SYSERROR("inotify event with no name");
+
+               if (ie->mask & IN_UNMOUNT) {
+                       DEBUG("watched directory removed");
+                       goto out;
+               }
+
+               SYSERROR("inotify event with no name (mask %d)", ie->mask);
                return -1;
        }
 
@@ -161,10 +169,9 @@ static int utmp_get_runlevel(struct lxc_utmp *utmp_data)
        struct utmpx *utmpx;
        char path[MAXPATHLEN];
        struct lxc_handler *handler = utmp_data->handler;
-       struct lxc_conf *conf = handler->conf;
 
-       if (snprintf(path, MAXPATHLEN, "%s/var/run/utmp", conf->rootfs.path) >
-           MAXPATHLEN) {
+       if (snprintf(path, MAXPATHLEN, "/proc/%d/root/var/run/utmp",
+                    handler->pid) > MAXPATHLEN) {
                ERROR("path is too long");
                return -1;
        }
@@ -211,19 +218,20 @@ static int utmp_get_ntasks(struct lxc_handler *handler)
 int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
                          struct lxc_handler *handler)
 {
-       struct lxc_conf *conf = handler->conf;
        char path[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 events as well.
+       /* 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
+        * events as well.
         */
-       if (snprintf(path, MAXPATHLEN, "%s/var/run", conf->rootfs.path) >
-           MAXPATHLEN) {
+       if (snprintf(path, MAXPATHLEN, "/proc/%d/root/var/run",
+                    handler->pid) > MAXPATHLEN) {
                ERROR("path is too long");
                return -1;
        }