From: Mark Huang <mlhuang@cs.princeton.edu>
Date: Tue, 21 Jun 2005 18:48:19 +0000 (+0000)
Subject: - add support for booting from USB flash device.
X-Git-Tag: planetlab-3_3-rc2~16
X-Git-Url: http://git.onelab.eu/?p=bootcd.git;a=commitdiff_plain;h=36e2a978768633b0c489e2e912297ac945f747c6

- add support for booting from USB flash device.
- the way this works is to loopback mount the usual ISO9660 image, which
  should reside as a regular file on the (presumably FAT) filesystem on
  the key.
---

diff --git a/conf_files/pl_sysinit b/conf_files/pl_sysinit
index 50a6b5c..9ec956f 100755
--- a/conf_files/pl_sysinit
+++ b/conf_files/pl_sysinit
@@ -9,12 +9,15 @@ echo "pl_sysinit: invoking hardware initialization script"
 /etc/init.d/pl_hwinit
 
 echo "pl_sysinit: finding cd to mount on /usr"
-test_devices=/sys/block/*
 mounted=0
 initrd_version=$(/bin/cat /pl_version)
 mkdir /usr
 
-for device in $test_devices; do
+# so that * expands to empty string if there are no block
+# devices
+shopt -s nullglob
+
+for device in /sys/block/*; do
     device=$(/bin/basename $device)
 
     # skipping any devices that start with md or ra (ram) or lo (loop) or
@@ -24,6 +27,28 @@ for device in $test_devices; do
 	[ "$start_device" == "lo" ] || [ "$start_device" == "fd" ]; then
 	continue
     fi
+
+    # If this is a removable (e.g., USB flash) device, then try to
+    # look for an ISO image on each of its partitions.
+    if [ "$(cat /sys/block/$device/removable)" = "1" ] ; then
+	partitions=$(/bin/awk "\$4 ~ /${device}[0-9]*/ { print \$4 }" /proc/partitions)
+	for partition in $partitions ; do
+	    echo "pl_sysinit: checking $partition for iso image"
+	    if /bin/mount -o ro -t msdos,ext2 /dev/$partition /usr 2>&1 > /dev/null ; then
+		# Look for the first ISO image
+		for iso in /usr/*.iso ; do
+		    if /sbin/losetup /dev/loop0 $iso ; then
+			echo "pl_sysinit: using $iso on $partition"
+			device="loop0"
+			break
+		    fi
+		done
+		if [ "$device" != "loop0" ] ; then
+		    /bin/umount /usr 2>&1 > /dev/null
+		fi
+	    fi
+	done
+    fi
     
     echo "pl_sysinit: checking $device for /usr contents"
     /bin/mount -o ro -t iso9660 /dev/$device /usr 2>&1 > /dev/null