[lxc-devel] [PATCH] don't leak the rootfs.pin fd into the container

[Serge Hallyn]

Quoting Ward, David - 0663 - MITLL (david.ward at ll.mit.edu):
> Hi Serge,
> 
> This patch seems to have introduced a regression.  When I use
> lxc-execute with a very simple container (which only sets the
> utsname), the terminal input is not forwarded to the application
> anymore.  In particular, running "lxc-execute -n $CONTAINER -- bash"
> returns immediately without opening a shell.  (This is with Fedora
> 18 and kernel 3.8.2.)

Thanks, David.  The following patch definately looks like it is
needed.  It may or may not fix the bug you're seeing.  Can you
confirm?

  Subject: [PATCH 1/1] rootfs pin: fix two bugs

1. if there's no rootfs, return -2, not 0.
2. don't close pinfd unconditionally in do_start().

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
---
 src/lxc/conf.c  | 2 +-
 src/lxc/start.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index add3c74..97b4ae4 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -578,7 +578,7 @@ int pin_rootfs(const char *rootfs)
 	int ret, fd;
 
 	if (rootfs == NULL || strlen(rootfs) == 0)
-		return 0;
+		return -2;
 
 	if (!realpath(rootfs, absrootfs)) {
 		SYSERROR("failed to get real path for '%s'", rootfs);
diff --git a/src/lxc/start.c b/src/lxc/start.c
index 75d1fd6..51b2f06 100644
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -652,7 +652,8 @@ static int do_start(void *data)
 	lxc_sync_fini_parent(handler);
 
 	/* don't leak the pinfd to the container */
-	close(handler->pinfd);
+	if (handler->pinfd >= 0)
+		close(handler->pinfd);
 
 	/* Tell the parent task it can begin to configure the
 	 * container and wait for it to finish
-- 
1.8.1.2