image.bbclass: avoid boot error on read-only systemd image

New version of systemd implements a new feature of updating /etc
or /var when needed at boot. For details, please see link below.

Opointer.de/blog/projects/stateless.html

For now, at boot time, the systemd-sysusers.service would update user
database files (/etc/passwd, /etc/group, etc.) according to the configuration
files under /usr/lib/sysusers.d. This step is necessary for other systemd
services to work correctly. Examples of such services are systemd-resolved
and systemd-tmpfiles-setup.

The problem is that on a read-only file system, that is, if /etc is read-only,
the user database files could not be updated, causing failures of services.

This patch fixes this problem by adding users/groups at rootfs time.

(From OE-Core rev: 2501c2f03f24fbbefd9999dd444318704d8aa8c2)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index 832c7384c6..34e9f4cba5 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -215,6 +215,27 @@ read_only_rootfs_hook () {
                         fi
                 fi
         fi
+
+        if ${@bb.utils.contains("DISTRO_FEATURES", "systemd", "true", "false", d)}; then
+            # Update user database files so that services don't fail for a read-only systemd system
+            for conffile in ${IMAGE_ROOTFS}/usr/lib/sysusers.d/systemd.conf ${IMAGE_ROOTFS}/usr/lib/sysusers.d/systemd-remote.conf; do
+                [ -e $conffile ] || continue
+                grep -v "^#" $conffile | sed -e '/^$/d' | while read type name id comment; do
+                    if [ "$type" = "u" ]; then
+                        useradd_params=""
+                        [ "$id" != "-" ] && useradd_params="$useradd_params --uid $id"
+                        [ "$comment" != "-" ] && useradd_params="$useradd_params --comment $comment"
+                        useradd_params="$useradd_params --system $name"
+                        eval useradd --root ${IMAGE_ROOTFS} $useradd_params || true
+                    elif [ "$type" = "g" ]; then
+                        groupadd_params=""
+                        [ "$id" != "-" ] && groupadd_params="$groupadd_params --gid $id"
+                        groupadd_params="$groupadd_params --system $name"
+                        eval groupadd --root ${IMAGE_ROOTFS} $groupadd_params || true
+                    fi
+                done
+            done
+        fi
 }
 
 PACKAGE_EXCLUDE ??= ""