Parsing cmdline and importing boot-type files (#6, #7)

Author: moul

Makefile

@@ -1,7 +1,7 @@
 S3_TARGET ?=	s3://$(shell whoami)/
 BUSYBOX_URL ?=	http://launchpadlibrarian.net/181784411/busybox-static_1.22.0-8ubuntu1_armhf.deb
 KERNEL_URL ?=	http://ports.ubuntu.com/ubuntu-ports/dists/lucid/main/installer-armel/current/images/versatile/netboot/vmlinuz
-CMDLINE ?=	'root=/dev/ram'
+CMDLINE ?=	ip=dhcp root=/dev/nbd0 nbd.max_parts=8 boot=local nometadata
 
 
 .PHONY: publish_on_s3 qemu dist dist_do dist_teardown all
@@ -16,7 +16,7 @@ qemu:    vmlinuz initrd.gz
 		-kernel ./vmlinuz \
 		-initrd ./initrd.gz \
 		-m 256 \
-		-append $(CMDLINE)
+		-append "$(CMDLINE)"
 
 publish_on_s3:	uInitrd initrd.gz
 	for file in $<; do \

tree/boot-nbd

@@ -0,0 +1,19 @@
+# -*- shell-script -*-
+
+mountroot() {
+    echo "boot-nbd.mountroot(): TODO"
+    # /scripts/local-top/ocs-nbd
+    # mkdir -p /mnt/root
+    # mount /dev/mapper/nbd0
+    # echo 0x0100 > /proc/sys/kernel/real-root-dev
+    # mount -o move /dev /mnt/dev
+    # mount -o move /dev/pts /mnt/dev/pts
+    # mount -o move /sys /mnt/sys
+    # mount -o move /proc /mnt/proc
+    # mount -o move /run /mnt/run
+    # sync
+    # echo "Let's play"
+    # export PS1="# "
+    # /bin/sh
+    # exec switch_root /mnt/root /init
+}

tree/boot-rescue

@@ -0,0 +1,5 @@
+# -*- shell-script -*-
+
+mountroot() {
+    echo "boot-rescue.mountroot(): TODO"
+}

tree/functions

@@ -35,19 +35,20 @@ signal_state() {
 
     retries=0
     while [ "${retries}" -lt "${RETRIES}" ]; do
-	log_begin_msg "Signaling the server is ${state} to the control plane"
-	http_patch "${METADATA_IP}" "${METADATA_PORT}" "{\"state_detail\": \"${state}\"}"
-	if [ ${?} -eq 0 ]; then
+        log_begin_msg "Signaling the server is ${state} to the control plane"
+        has_opt nometadata || \
+            http_patch "${METADATA_IP}" "${METADATA_PORT}" "{\"state_detail\": \"${state}\"}"
+        if [ ${?} -eq 0 ]; then
             log_success_msg "control plane is aware that server is ${state}"
             log_end_msg
             return
-	else
+        else
             log_failure_msg "unable to signal server is ${state}"
             log_end_msg
-	fi
-	
+        fi
+
         retries=$((${retries}+1))
-	test ${retries} -eq ${RETRIES} || sleep ${SLEEP_BETWEEN_RETRIES}
+        test ${retries} -eq ${RETRIES} || sleep ${SLEEP_BETWEEN_RETRIES}
     done
 
     log_failure_msg "Unsable to signal state=$state after ${RETRIES} attempts, continuing boot..."
@@ -70,7 +71,16 @@ content-type: application/json
 Content-Length: ${content_length}
 
 ${content}"
-    
+
     ( echo -n "${patch_body}" && sleep 3 ) \
-	| nc "${metadata_ip}" "${metadata_port}" | grep '200 OK'
+        | nc "${metadata_ip}" "${metadata_port}" | grep '200 OK'
+}
+
+# Function for parsing command line options with "=" in them
+get_opt() {
+    cat /proc/cmdline | tr " " "\n" | cut -d "=" -f 2
+}
+
+has_opt() {
+    cat /proc/cmdline | tr " " "\n" | grep "^$1\$" >/dev/null
 }

tree/init

@@ -1,12 +1,8 @@
 #!/bin/sh
 
-set -x
-
-
 # Create all the symlinks to /bin/busybox
 /bin/busybox --install -s
 
-
 # Mount things needed by this script
 [ -d /dev ] || mkdir -m 0755 /dev
 [ -d /sys ] || mkdir /sys
@@ -26,27 +22,57 @@ mount -t devpts -o noexec,nosuid,gid=5,mode=0620 none /dev/pts
 signal_state kernel-started
 
 
-# NBD boot
-# . /scripts/functions
-# /scripts/local-top/ocs-nbd
-# mkdir -p /mnt/root
-# mount /dev/mapper/nbd0
-# echo 0x0100 > /proc/sys/kernel/real-root-dev
-# mount -o move /dev /mnt/dev
-# mount -o move /dev/pts /mnt/dev/pts
-# mount -o move /sys /mnt/sys
-# mount -o move /proc /mnt/proc
-# mount -o move /run /mnt/run
-# sync
-# echo "Let's play"
-# export PS1="# "
-# /bin/sh
-# exec switch_root /mnt/root /init
+# Defaults
+init="/sbin/init"
+root="/dev/nbd0"
+boot="local"
+
+# Process command line options
+for i in $(cat /proc/cmdline); do
+    case "${i}" in
+        root\=*)
+            root=$(get_opt "${i}")
+            ;;
+        init\=*)
+            init=$(get_opt "${i}")
+            ;;
+        boot\=*)
+            init=$(get_opt "${i}")
+            ;;
+    esac
+done
+
+
+# Import boot-type functions
+case "${boot}" in
+    local)
+        . ./boot-nbd
+        ;;
+    rescue)
+        . ./boot-rescue
+        ;;
+esac
+
+
+# Mountroot
+mountroot
 
 
 # Signal to the console that the server is booted
 signal_state booted
 
 
-# Debug fallback
+# Check if $init exists and is executable
+if [[ -x "/newroot/${init}" ]] ; then
+    # Unmount all other mounts so that the ram used by
+    # the initramfs can be cleared after switch_root
+    umount /sys /proc
+
+    # Switch to the new root and execute init
+    exec switch_root /newroot "${init}"
+fi
+
+
+# This will only be run if the exec above failed
+echo "Failed to switch_root, dropping to a shell"
 exec /bin/sh