generator: Drop fallback mechanism (OnFailure=nonisuNAME.service)

Unfortunately, the fallback mechanism, used when ISU service fails
to start can not be used in practice because:

 - it breaks socket activated services, as socket passing is defined
   in .socket units explicitly (ie. .socket specifies eg. Service=a.service,
   and if fallaback uinit would be started then sockets would not be
   passed correctly),

 - it breaks dbus-activated services, as copying original service file
   to nonisuNAME.service causes two services to specify same BusName= name

Change-Id: I7dc187ff367920bc2bfcf3988506f513278a932a

diff --git a/doc/GUIDE.md b/doc/GUIDE.md
index 49eadf1..624574b 100644 (file)
--- a/doc/GUIDE.md
+++ b/doc/GUIDE.md
@@ -173,8 +173,6 @@ and performing the following steps:
 2. Installing all `ISU package` `systemd` service files to the `systemd` standard locations
 (`/run/generator/systemd`) to override system-default service files (`/usr/lib/systemd`),
 which are checked in later
-3. Altering installed `systemd` service files to provide fallback to start non-ISU (original)
-services in case of situation, where an ISU service do not work and/or keeps crashing.
 
 #### Details of `isu-generator` operation
 
@@ -197,9 +195,6 @@ The script performs the following operations:
      - note that for `user-services` the user session path is different and is defined when
        the program is invoked by the `systemd --user` instance.
 
-   - installs original unit name under `nonisu-SERVICE_NAME` for use in
-     case of ISU package failure
-
    - installs mount unit to mount ISU rootfs in `/run/isu/ISU_PKG_NAME/rootfs`
      (e.g. `run-isu-dlog-rootfs.mount`)
 
@@ -218,18 +213,6 @@ On a running system, the ISU package can be seen under the `/run/isu/dlog` hiera
                    ├── /usr/bin/dlog_logger
                    ├── /etc/dlog.conf.d
 
-As a fallback mechanism, the following procedure is used:
-* original unit is copied to the `systemd-generator` directory as the `nonisu-NAME`
-  file, which can be referenced as a normal unit name
-* new service file is automatically modified to include the following:
-
-      OnFailure=nonisu-NAME
-      Conflicts=nonisu-NAME
-
-  which will automatically start the original unit if the ISU package's
-  service fails to start or if the signature verification fails.
-
-
 ### Management of ISU packages
 
 Currently management is assumed to be handled manually by the system administrator.

diff --git a/src/systemd_generator/README.md b/src/systemd_generator/README.md
index 4517f61..f1aceb6 100644 (file)
--- a/src/systemd_generator/README.md
+++ b/src/systemd_generator/README.md
@@ -32,9 +32,6 @@ The generator:
      - note that for user-services (user session path is different and is defined during program invocation
        by `systemd --user` instance.
 
-   - installs original unit name under `nonisu-SERVICE_NAME` for use in
-     case of ISU package failure
-
    - installs mount unit to mount ISU rootfs in `/run/isu/ISU_PKG_NAME/rootfs`
      (eg. `run-isu-dlog-rootfs.mount`)
 
@@ -52,14 +49,3 @@ In running system ISU package is seen under `/run/isu/dlog` hierarchy as follows
                └── rootfs
                    ├── /usr/bin/dlog_logger
                    ├── /etc/dlog.conf.d
-
-As a fallback mechanism following is used:
-* original unit is copied to systemd generator directory as `nonisu-NAME`
-  file, which can be referenced as normal unit name
-* new service file is automatically modified to include
-
-    OnFailure=nonisu-NAME
-    Conflicts=nonisu-NAME
-
-  Which will cause to automatically start original unit if ISU package's
-  service fails to start (or signature verification fails).

diff --git a/src/systemd_generator/isu-generator b/src/systemd_generator/isu-generator
index e245140..3594497 100755 (executable)
--- a/src/systemd_generator/isu-generator
+++ b/src/systemd_generator/isu-generator
@@ -43,13 +43,9 @@ install_units()
 
        rm -f "${new_srv_path}" "${new_srv_path}.tmp"
 
-       # 1st step: copy ISU package's .service file to generator dir and original .service under diffeerent name
-       # (nonisu-.. -> different name is needed as original .service will be masked by our new service from ISU)
        cat "$srv_path" > "$new_srv_path".tmp || return 1
        if [ -f "$SERVICES_DIR/${srv_fname}" ]; then
-               cp -a "$SERVICES_DIR/${srv_fname}" "$UNITDIR/nonisu-${srv_fname}" || return 1
-
-               # 2nd step: generate mount unit for ISU image and extend the service file to use it
+               # generate mount unit for ISU image and extend the service file to use it
                local mount_unit="run-isu-$(systemd-escape ${isu_pkg_name})-rootfs.mount"
                cat <<EOF >> "$UNITDIR/$mount_unit" || return 1
 # This unit file has been automatically generated by isu-generator.
@@ -69,12 +65,10 @@ EOF
 [Unit]
 After=${mount_unit}
 BindsTo=${mount_unit}
-OnFailure=nonisu-${srv_fname}
-Conflicts=nonisu-${srv_fname}
 EOF
        fi
 
-       # 3rd step: make new unit visible
+       # make new unit visible
        mv "${new_srv_path}.tmp" "${new_srv_path}" || return 1
 
        return 0