busybox-syslog: Log to the MMC card if present

If the first partition of a MMC card is mounted and has a logs/
directory syslog will start to write log messages to the MMC card
in the directory /media/mmcblk0p1.

recipes-apps/busybox/busybox_sysmocom.inc

@@ -1,6 +1,6 @@
 SYSMOCOM := "${@os.path.dirname(bb.data.getVar('FILE', d, True))}"
 FILESEXTRAPATHS_prepend := "${SYSMOCOM}/files:"
-PRINC = "11"
+PRINC = "12"
 
 SRC_URI += "file://busybox-ifplugd.sh \
             file://ifplugd.sh"

recipes-apps/busybox/files/syslog.conf

@@ -0,0 +1,22 @@
+DESTINATION="buffer"		# log destinations (buffer file remote)
+MARKINT=20			# intervall between --mark-- entries
+LOGFILE=/var/log/messages	# where to log (file)
+REMOTE=loghost:514		# where to log (syslog remote)
+REDUCE=no			# reduce-size logging
+#ROTATESIZE=0			# rotate log if grown beyond X [kByte] (incompatible with busybox)
+#ROTATEGENS=3			# keep X generations of rotated logs (incompatible with busybox)
+BUFFERSIZE=64			# size of circular buffer [kByte]
+FOREGROUND=no			# run in foreground (don't use!)
+LOGLEVEL=4
+
+# magic when a MMC card is mounted
+USING_MMC_CARD=`/bin/mount | grep /media/mmcblk0p1 | wc -l`
+if [ 1 -eq $USING_MMC_CARD ] ; then
+	if [ -e /media/mmcblk0p1/logs ] ; then
+		echo "Using mmc card"
+		LOGFILE=/media/mmcblk0p1/logs/messages
+		DESTINATION="file"
+		ROTATESIZE=2048
+		ROTATEGENS=20
+	fi
+fi