Write sync status to HDD_LOG/log2ram.log. (#7)

* Write sync status to HDD_LOG/log2ram.log.

- Store sync status directly in the HDD log, to make sure we know
  about it if something fails.  This won't help if the HDD_LOG
  variable is borked, but it'll help with everything else.

- Made sync a function to avoid repeating five lines three times.

- log2ram now requires (cp or rsync) and tee, mount, umount.

* Split sync into syncFromDisk and syncToDisk.

- After restarting, I realized that I had combined both types of sync
  into one line, when the syncing failed.  This fixes that bug.

* Exclude log2ram.log from rsync so rsync doesn't delete it on sync.

log2ram

@@ -2,8 +2,33 @@
 
 HDD_LOG=/var/log.hdd/
 RAM_LOG=/var/log/
+LOG2RAM_LOG="${HDD_LOG}log2ram.log"
 SIZE=40M
 USE_RSYNC=false
+LOG_OUTPUT="tee -a $LOG2RAM_LOG"
+
+syncToDisk () {
+    [ -d $HDD_LOG ] || echo "ERROR: $HDD_LOG doesn't exist!  Can't sync."
+    [ -d $HDD_LOG ] || exit 1
+
+    if [ "$USE_RSYNC" = true ]; then
+        rsync -aXWv --delete --exclude log2ram.log --links $RAM_LOG $HDD_LOG 2>&1 | $LOG_OUTPUT
+    else
+        cp -rfup $RAM_LOG -T $HDD_LOG 2>&1 | $LOG_OUTPUT
+    fi
+}
+
+syncFromDisk () {
+    [ -d $HDD_LOG ] || echo "ERROR: $HDD_LOG doesn't exist!  Can't sync."
+    [ -d $HDD_LOG ] || exit 1
+
+    if [ "$USE_RSYNC" = true ]; then
+        rsync -aXWv --delete --exclude log2ram.log --links $HDD_LOG $RAM_LOG 2>&1 | $LOG_OUTPUT
+    else
+        cp -rfup $HDD_LOG -T $RAM_LOG 2>&1 | $LOG_OUTPUT
+    fi
+}
+
 
 case "$1" in
   start)
@@ -11,28 +36,16 @@ case "$1" in
       mount --bind $RAM_LOG $HDD_LOG
       mount --make-private $HDD_LOG
       mount -t tmpfs -o nosuid,noexec,nodev,mode=0755,size=$SIZE log2ram $RAM_LOG
-      if [ "$USE_RSYNC" = true ]; then
-          rsync -aXWv --delete --links $HDD_LOG $RAM_LOG
-      else
-          cp -rfup $HDD_LOG -T $RAM_LOG
-      fi
+      syncFromDisk
       ;;
 
   stop)
-      if [ "$USE_RSYNC" = true ]; then
-          rsync -aXWv --delete --links $RAM_LOG $HDD_LOG
-      else
-          cp -rfup $RAM_LOG -T $HDD_LOG
-      fi
+      syncToDisk
       umount -l $RAM_LOG
       umount -l $HDD_LOG
       ;;
 
   write)
-      if [ "$USE_RSYNC" = true ]; then
-          rsync -aXWv --delete --links $RAM_LOG $HDD_LOG
-      else
-          cp -rfup $RAM_LOG -T $HDD_LOG
-      fi
+      syncToDisk
       ;;
 esac