From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Mon, 4 Dec 2017 11:26:55 +0000 (+0100)
Subject: attach: do not fail on non-existing namespaces
X-Git-Tag: lxc-2.0.10~526
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4feff04ae3e3b885a334a737b62521a4fe8db113;p=thirdparty%2Flxc.git

attach: do not fail on non-existing namespaces

Closes #1993.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index 611432416..4ccf5c4a5 100644
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -273,8 +273,15 @@ static int in_same_namespace(pid_t pid1, pid_t pid2, const char *ns)
 	struct stat ns_st1, ns_st2;
 
 	ns_fd1 = lxc_preserve_ns(pid1, ns);
-	if (ns_fd1 < 0)
+	if (ns_fd1 < 0) {
+		/* The kernel does not support this namespace. This is not an
+		 * error.
+		 */
+		if (errno == ENOENT)
+			return -EINVAL;
+
 		goto out;
+	}
 
 	ns_fd2 = lxc_preserve_ns(pid2, ns);
 	if (ns_fd2 < 0)
diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 936603d82..148f23429 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -1964,8 +1964,9 @@ int lxc_preserve_ns(const int pid, const char *ns)
 	ret = snprintf(path, __NS_PATH_LEN, "/proc/%d/ns%s%s", pid,
 		       !ns || strcmp(ns, "") == 0 ? "" : "/",
 		       !ns || strcmp(ns, "") == 0 ? "" : ns);
+	errno = EFBIG;
 	if (ret < 0 || (size_t)ret >= __NS_PATH_LEN)
-		return -1;
+		return -EFBIG;
 
 	return open(path, O_RDONLY | O_CLOEXEC);
 }