busybox: cleanup persistent log setup when debugging is enabled

The ancient approach of symlinking /var/log to /storage/log doesn't
play nice with systemd as it doesn't setup proper dependencies and
unmounting /storage during shutdown may fail because systemd doesn't
know that it's needed for /var/log.

Use a conditional bind mount instead so systemd can automatically
create proper dependencies and unmount filesystems in the correct order.

Also store the persistent logfiles on /storage in a .cache/log
directory instead of log to avoid confusing users - users can access
logfiles via /var/log.

Note: we can't use tmpfiles.d to create the .cache/log directory on
/storage because that would run after local-fs.target but we need
the .log directory before that so it has to be done via a one-shot
service.

Signed-off-by: Matthias Reichl <hias@horus.com>

packages/sysutils/busybox/package.mk

@@ -185,7 +185,6 @@ post_install() {
   enable_service shell.service
   enable_service show-version.service
   enable_service var.mount
-  enable_service var-log-debug.service
   enable_service fs-resize.service
   listcontains "${FIRMWARE}" "rpi-eeprom" && enable_service rpi-flash-firmware.service
 

packages/sysutils/busybox/system.d/storage-log.service

@@ -0,0 +1,9 @@
+[Unit]
+Description=Create Persistent Log Directory on /storage
+DefaultDependencies=no
+RequiresMountsFor=/storage
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/mkdir -p /storage/.cache/log/journal

packages/sysutils/busybox/system.d/var-log-debug.service

@@ -1,18 +0,0 @@
-[Unit]
-Description=Debug /var/log relink
-DefaultDependencies=false
-After=var.mount
-Before=systemd-journal-flush.service
-ConditionKernelCommandLine=!installer
-ConditionKernelCommandLine=|debugging
-ConditionPathExists=|/storage/.cache/debug.libreelec
-
-[Service]
-Type=oneshot
-ExecStartPre=/bin/rm -rf /var/log
-ExecStartPre=-/bin/mkdir -p /storage/log/journal
-ExecStart=-/bin/ln -sf /storage/log /var/log
-RemainAfterExit=yes
-
-[Install]
-WantedBy=sysinit.target

packages/sysutils/busybox/system.d/var-log.mount

@@ -0,0 +1,13 @@
+[Unit]
+Description=Persistent Log Storage
+RequiresMountsFor=/var /storage
+Requires=storage-log.service
+After=storage-log.service
+ConditionKernelCommandLine=!installer
+ConditionKernelCommandLine=|debugging
+ConditionPathExists=|/storage/.cache/debug.libreelec
+
+[Mount]
+What=/storage/.cache/log
+Where=/var/log
+Options=bind