From 729f9da8729df04fc4a20898c7b794047b97daed Mon Sep 17 00:00:00 2001
From: Michael Marineau <michael.marineau@coreos.com>
Date: Wed, 3 Dec 2014 13:33:50 -0800
Subject: [PATCH] common: make sure /etc/mtab is correct before mounting
 anything

If mtab ever gets replaced by a regular file all sorts of things break.
---
 build_image             | 2 ++
 common.sh               | 7 +++++++
 image_to_vm.sh          | 2 ++
 sdk_lib/enter_chroot.sh | 2 ++
 4 files changed, 13 insertions(+)

diff --git a/build_image b/build_image
index e5891f9ed2..a64261d11a 100755
--- a/build_image
+++ b/build_image
@@ -149,6 +149,8 @@ users:
 EOF
 fi
 
+fix_mtab
+
 if [[ "${DEV_IMAGE}" -eq 1 ]]; then
   create_dev_image ${COREOS_DEVELOPER_IMAGE_NAME} ${DISK_LAYOUT} ${FLAGS_group}
   if [[ ${FLAGS_extract_update} -eq ${FLAGS_TRUE} ]]; then
diff --git a/common.sh b/common.sh
index 2550069620..573b309a95 100644
--- a/common.sh
+++ b/common.sh
@@ -601,6 +601,13 @@ is_mounted() {
   fi
 }
 
+fix_mtab() {
+    local root="$1" mounts="../proc/self/mounts"
+    if [[ "$(readlink "${root}/etc/mtab")" != "${mounts}" ]]; then
+        sudo ln -sf "${mounts}" "${root}/etc/mtab"
+    fi
+}
+
 get_git_id() {
   git var GIT_COMMITTER_IDENT | sed -e 's/^.*<\(\S\+\)>.*$/\1/'
 }
diff --git a/image_to_vm.sh b/image_to_vm.sh
index 162aded577..cb8341f6fd 100755
--- a/image_to_vm.sh
+++ b/image_to_vm.sh
@@ -103,6 +103,8 @@ fi
 # Make sure things are cleaned up on failure
 trap vm_cleanup EXIT
 
+fix_mtab
+
 # Setup new (raw) image, possibly resizing filesystems
 setup_disk_image "${FLAGS_disk_layout}"
 
diff --git a/sdk_lib/enter_chroot.sh b/sdk_lib/enter_chroot.sh
index a31855cc67..036d6d3255 100755
--- a/sdk_lib/enter_chroot.sh
+++ b/sdk_lib/enter_chroot.sh
@@ -209,6 +209,8 @@ setup_env() {
       fi
     done
 
+    fix_mtab "${FLAGS_chroot}"
+
     debug "Mounting chroot environment."
     MOUNT_CACHE=$(echo $(awk '{print $2}' /proc/mounts))