From: Serge E. Hallyn <serge.hallyn@canonical.com>
Date: Sun, 7 Aug 2011 10:25:07 +0000 (+0200)
Subject: Use container's /run/utmp if it exists
X-Git-Tag: lxc-0.7.5~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4cb05a609b308f0ddf37a9f4bd65e1a37c6b607e;p=thirdparty%2Flxc.git

Use container's /run/utmp if it exists

If /var/run is a symlink to /run in the container, then opening
/proc/<pid>/root/var/run/utmp will end up opening the host's utmp.
Therefore the hack detecting shutdown through utmp fails.

Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
---

diff --git a/src/lxc/utmp.c b/src/lxc/utmp.c
index 691c3ef9d..b6469b09a 100644
--- a/src/lxc/utmp.c
+++ b/src/lxc/utmp.c
@@ -170,6 +170,15 @@ static int utmp_get_runlevel(struct lxc_utmp *utmp_data)
 	char path[MAXPATHLEN];
 	struct lxc_handler *handler = utmp_data->handler;
 
+	if (snprintf(path, MAXPATHLEN, "/proc/%d/root/run/utmp",
+		     handler->pid) > MAXPATHLEN) {
+		ERROR("path is too long");
+		return -1;
+	}
+
+	if (!access(path, F_OK) && !utmpxname(path))
+		goto utmp_ok;
+
 	if (snprintf(path, MAXPATHLEN, "/proc/%d/root/var/run/utmp",
 		     handler->pid) > MAXPATHLEN) {
 		ERROR("path is too long");
@@ -181,6 +190,8 @@ static int utmp_get_runlevel(struct lxc_utmp *utmp_data)
 		return -1;
 	}
 
+utmp_ok:
+
 	setutxent();
 
 	while ((utmpx = getutxent())) {
@@ -219,6 +230,7 @@ int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
 			  struct lxc_handler *handler)
 {
 	char path[MAXPATHLEN];
+	char path2[MAXPATHLEN];
 	int fd, wd;
 	struct lxc_utmp *utmp_data;
 	struct lxc_conf *conf = handler->conf;
@@ -230,6 +242,19 @@ int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
 	 * in utmp at the moment, but want to watch for delete and create
 	 * events as well.
 	 */
+	if (snprintf(path, MAXPATHLEN, "/proc/%d/root/run",
+		     handler->pid) > MAXPATHLEN) {
+		ERROR("path is too long");
+		return -1;
+	}
+	if (snprintf(path2, MAXPATHLEN, "/proc/%d/root/run/utmp",
+		     handler->pid) > MAXPATHLEN) {
+		ERROR("path is too long");
+		return -1;
+	}
+	if (!access(path2, F_OK))
+		goto run_ok;
+
 	if (snprintf(path, MAXPATHLEN, "/proc/%d/root/var/run",
 		     handler->pid) > MAXPATHLEN) {
 		ERROR("path is too long");
@@ -241,6 +266,8 @@ int lxc_utmp_mainloop_add(struct lxc_epoll_descr *descr,
 		return 0;
 	}
 
+run_ok:
+
 	utmp_data = (struct lxc_utmp *)malloc(sizeof(struct lxc_utmp));
 
 	if (NULL == utmp_data) {