#!/bin/bash

. /etc/init.d/pl_functions

. /tmp/planet.cnf

# Run gpg once to create default options
GNUPGHOME=/root
export GNUPGHOME
/usr/bin/gpg --yes 2>/dev/null </dev/null

# if this file is present, cancel the boot (exit this script)
CANCEL_BOOT_FLAG=/tmp/CANCEL_BOOT

# how many times to fail in attempting to contact primary server
# before falling back to original. if the backup fails this many times
# too, then the process is repeated started with the primary server
ATTEMPTS_BEFORE_BACKUP=3

# where all the configuration files for contacting
# the boot server are stored
BOOT_DIR=/usr/boot/

# get the server we are going to be contacting
BOOT_SERVER=$(cat $BOOT_DIR/boot_server)
BOOT_SERVER_PORT=$(cat $BOOT_DIR/boot_server_port)

# the file to request from the boot server
BOOT_SERVER_PATH=$(cat $BOOT_DIR/boot_server_path)

# location of the cacert for this boot server
BOOT_SERVER_CACERT=$BOOT_DIR/cacert.pem

# location of the gpg key ring to verify scripts
BOOT_SERVER_GPG_KEYRING=$BOOT_DIR/pubring.gpg

# get the backup server we are going to be contacting
BACKUP_BOOT_SERVER=$(cat $BOOT_DIR/backup/boot_server)
BACKUP_BOOT_SERVER_PORT=$(cat $BOOT_DIR/backup/boot_server_port)

# the file to request from the backup boot server
BACKUP_BOOT_SERVER_PATH=$(cat $BOOT_DIR/backup/boot_server_path)

# location of the cacert for the backup boot server
BACKUP_BOOT_SERVER_CACERT=$BOOT_DIR/backup/cacert.pem

# location of the gpg key ring for backup server to verify scripts
BACKUP_BOOT_SERVER_GPG_KEYRING=$BOOT_DIR/backup/pubring.gpg

# location of a file containing this boot cd version
BOOT_VERSION_FILE=/pl_version

# the locations of the downloaded scripts
UNVERIFIED_SCRIPT=/tmp/bootscript.gpg
VERIFIED_SCRIPT=/tmp/bootscript


# --------------------------


# now, contact the boot server, run the script, and do it over again.
contact_count=0

# set to one when we are trying to contact backup server
on_backup_server=0

# start out contacting the primary servers
CONNECT_BOOT_SERVER=$BOOT_SERVER
CONNECT_BOOT_SERVER_PORT=$BOOT_SERVER_PORT
CONNECT_BOOT_SERVER_PATH=$BOOT_SERVER_PATH
CONNECT_BOOT_SERVER_GPG_KEYRING=$BOOT_SERVER_GPG_KEYRING
CONNECT_BOOT_SERVER_CACERT=$BOOT_SERVER_CACERT

while : ; do

    if [[ -f $CANCEL_BOOT_FLAG ]]; then
        echo $(date "+%H:%M:%S") " pl_boot: got request to cancel boot, exiting"
        exit 0
    fi
    
    if [[ $contact_count -ge $ATTEMPTS_BEFORE_BACKUP ]]; then

        contact_count=0

        if [[ $on_backup_server == 1 ]]; then
            echo $(date "+%H:%M:%S") " pl_boot: failed to contact backup server, trying primary $BOOT_SERVER"

            on_backup_server=0

            CONNECT_BOOT_SERVER=$BOOT_SERVER
            CONNECT_BOOT_SERVER_PORT=$BOOT_SERVER_PORT
            CONNECT_BOOT_SERVER_PATH=$BOOT_SERVER_PATH
            CONNECT_BOOT_SERVER_GPG_KEYRING=$BOOT_SERVER_GPG_KEYRING
            CONNECT_BOOT_SERVER_CACERT=$BOOT_SERVER_CACERT
        else
            echo $(date "+%H:%M:%S") " pl_boot: failed to contact primary server, trying backup $BACKUP_BOOT_SERVER"

            on_backup_server=1

            CONNECT_BOOT_SERVER=$BACKUP_BOOT_SERVER
            CONNECT_BOOT_SERVER_PORT=$BACKUP_BOOT_SERVER_PORT
            CONNECT_BOOT_SERVER_PATH=$BACKUP_BOOT_SERVER_PATH
            CONNECT_BOOT_SERVER_GPG_KEYRING=$BACKUP_BOOT_SERVER_GPG_KEYRING
            CONNECT_BOOT_SERVER_CACERT=$BACKUP_BOOT_SERVER_CACERT
        fi
    fi

    if [[ $contact_count != 0 ]]; then

        echo $(date "+%H:%M:%S") " pl_boot: next attempt in 30s, to fetch script from server at $CONNECT_BOOT_SERVER"
	/bin/sleep 30
    fi

    # assemble the curl transaction
    CURL_CMD="/usr/bin/curl \
        --connect-timeout 60 \
        --max-time 600 \
        --form version=<$BOOT_VERSION_FILE \
        --form cmdline=</proc/cmdline \
        --form uptime=</proc/uptime \
        --form ifconfig=</tmp/ifconfig \
        --form nonce=</tmp/nonce \
        --location \
        --output $UNVERIFIED_SCRIPT \
        --sslv3  \
        --silent \
        --show-error \
        --fail \
        --stderr /tmp/curl_errors \
        --cacert $CONNECT_BOOT_SERVER_CACERT \
   https://$CONNECT_BOOT_SERVER:$CONNECT_BOOT_SERVER_PORT/$CONNECT_BOOT_SERVER_PATH"

    # assemble the gpg command line
    GPG_CMD="/usr/bin/gpg \
        --no-default-keyring \
        --keyring $CONNECT_BOOT_SERVER_GPG_KEYRING \
        --output $VERIFIED_SCRIPT \
        --always-trust \
        --decrypt $UNVERIFIED_SCRIPT"

    echo $(date "+%H:%M:%S") " pl_boot: generating new nonce"
    /usr/bin/head --bytes=32 /dev/urandom | \
    /usr/bin/od -tx1 -An --width=32 | \
    /bin/sed 's/ //g' > /tmp/nonce

    echo $(date "+%H:%M:%S") " pl_boot: fetching script from boot server $CONNECT_BOOT_SERVER"
    ((contact_count++))
    rm -f $UNVERIFIED_SCRIPT
    $CURL_CMD
    curl_err=$?
    if [ $curl_err -ne 0 ]; then
        echo $(date "+%H:%M:%S") " pl_boot: curl request failed with error $curl_err:"
        cat /tmp/curl_errors
        echo
        if [ -n "$DISCONNECTED_OPERATION" ]; then
            mkdir /tmp/boot-media
            mount -U "$DISCONNECTED_OPERATION" /tmp/boot-media
            cp /tmp/boot-media/bootscript.gpg $UNVERIFIED_SCRIPT
            umount /tmp/boot-media
            rmdir /tmp/boot-media
        else
            case $curl_err in
                6)
                    echo $(date "+%H:%M:%S") " This error likely indicates a networking configuration error. "
                    echo $(date "+%H:%M:%S") " Please, check whether you can ping this machine.  If you can, "
                    echo $(date "+%H:%M:%S") " we recommend checking your DNS settings.  If you cannot, then "
                    echo $(date "+%H:%M:%S") " please double check your network settings registered at PLC and "
                    echo $(date "+%H:%M:%S") " stored on this Boot Image."
                ;;
                60)
                    echo $(date "+%H:%M:%S") " This error likely indicates that the hardware clock is likely not set "
                    echo $(date "+%H:%M:%S") " to GMT.  The result is that authentication between the local and "
                    echo $(date "+%H:%M:%S") " remote site fails.  Please double check this machine's system "
                    echo $(date "+%H:%M:%S") " clock, and set it to GMT in the BIOS. If after rebooting the same "
                    echo $(date "+%H:%M:%S") " error occurs, please report the situation to support@planet-lab.org "
                    echo $(date "+%H:%M:%S") " with as much detail as possible."
                ;;
                *)
                    echo $(date "+%H:%M:%S") " The best-practice approach for handling this error is not yet "
                    echo $(date "+%H:%M:%S") " documented.  Please report this error to support@planet-lab.org "
                    echo $(date "+%H:%M:%S") " with as much detail as possible."
                ;;
            esac
	    # in any case display as much info as we can (see pl_functions)
	    pl_network_sanity_checks
	    # retry
            continue
        fi
    elif [ -n "$DISCONNECTED_OPERATION" ]; then
        mkdir /tmp/boot-media
        mount -U "$DISCONNECTED_OPERATION" /tmp/boot-media
        cp $UNVERIFIED_SCRIPT /tmp/boot-media
        umount /tmp/boot-media
        rmdir /tmp/boot-media
    fi 

    echo $(date "+%H:%M:%S") " pl_boot: verifying downloaded script"
    rm -f $VERIFIED_SCRIPT
    $GPG_CMD 2> /tmp/gpg_errors
    if [ $? -ne 0 ]; then
        echo $(date "+%H:%M:%S") " pl_boot: failed to verify file:"
        cat /tmp/gpg_errors
        echo
        continue
    fi
    echo $(date "+%H:%M:%S") " pl_boot: decrypted and verified script succesfully"

    echo $(date "+%H:%M:%S") " pl_boot: handing control to download script"
    rm -f $UNVERIFIED_SCRIPT
    chmod +x $VERIFIED_SCRIPT
    $VERIFIED_SCRIPT
    
    echo $(date "+%H:%M:%S") " pl_boot: downloaded script has returned"
done

echo $(date "+%H:%M:%S") " pl_boot: automatic boot process canceled by user"