[libvirt] [PATCH] Always pivot_root event if the new root source is '/'

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; This reverts commit c16b4c43fcdd8ec02581f38377983b2e0925bfcd Author: Daniel P. Berrange <berrange(a)redhat.com&gt; Date: Fri May 11 15:09:27 2012 +0100 Avoid LXC pivot root in the root source is still / This commit broke setup of /dev, because the code which deals with setting up a private /dev and /dev/pts only works if you do a pivotroot. The original intent of avoiding the pivot root was to try and ensure the new root has a minimumal mount tree. The better way todo this is to just unmount the bits we don't want (ie old /proc & /sys subtrees. So apply the logic from commit c529b47a756960d332fbe9903943dae855e7b949 Author: Daniel P. Berrange <berrange(a)redhat.com&gt; Date: Fri May 11 11:35:28 2012 +0100 Trim /proc & /sys subtrees before mounting new instances to the pivot_root codepath as well --- src/lxc/lxc_container.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index bad7938..b8fb14e 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -1345,6 +1345,13 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef, if (lxcContainerPivotRoot(root) < 0) goto cleanup; + /* Gets rid of any existing stuff under /proc, since we need new + * namespace aware versions of those. We must do /proc second + * otherwise we won't find /proc/mounts :-) */ + if (lxcContainerUnmountSubtree("/sys", false) < 0 || + lxcContainerUnmountSubtree("/proc", false) < 0) + goto cleanup; + /* Mounts the core /proc, /sys, etc filesystems */ if (lxcContainerMountBasicFS(vmDef, true, securityDriver) < 0) goto cleanup; @@ -1472,11 +1479,7 @@ static int lxcContainerSetupMounts(virDomainDefPtr vmDef, if (lxcContainerResolveSymlinks(vmDef) < 0) return -1; - /* If the user has specified a dst '/' with a source of '/' - * then we don't really want to go down the pivot root - * path, as we're just tuning the existing root - */ - if (root && root->src && STRNEQ(root->src, "/")) + if (root && root->src) return lxcContainerSetupPivotRoot(vmDef, root, ttyPaths, nttyPaths, securityDriver); else return lxcContainerSetupExtraMounts(vmDef, root, securityDriver); -- 1.7.10.2