Remove the a previous cgroup

As a previous run may have created a cgroup but died unexpectedly, the cgroup can be still there when we try to launch the container again with the same name. This patch removes the directory if it is present, if this one is not owned by caller or it is in use (that should not happen), the rmdir will fail with the corresponding errno. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

Remove the a previous cgroup
0dd4566e · Daniel Lezcano · 3a0f472d · 0dd4566e
Commit 0dd4566e authored Jul 16, 2009 by Daniel Lezcano
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cgroup.c src/lxc/cgroup.c +11 -0

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--- a/src/lxc/cgroup.c
+++ b/src/lxc/cgroup.c
@@ -94,6 +94,17 @@ int lxc_rename_nsgroup(const char *name, pid_t pid)
 	snprintf(oldname, MAXPATHLEN, "%s/%d", cgroup, pid);
 	snprintf(newname, MAXPATHLEN, "%s/%s", cgroup, name);

+	/* there is a previous cgroup, assume it is empty, otherwise
+	 * that fails */
+	if (!access(newname, F_OK)) {
+		ret = rmdir(newname);
+		if (ret) {
+			SYSERROR("failed to remove previous cgroup '%s'",
+				 newname);
+			return ret;
+		}
+	}
+
 	ret = rename(oldname, newname);
 	if (ret)
 		SYSERROR("failed to rename cgroup %s->%s", oldname, newname);