fwup.conf

# Firmware configuration file for a Vultr Server Image

require-fwup-version="0.15.0"  # For the trim() call

#
# Firmware metadata
#

# All of these can be overriden using environment variables of the same name.
#
#  Run 'fwup -m' to query values in a .fw file.
#  Use 'fw_printenv' to query values on the target.
#
# These are used by Nerves libraries to introspect.
define(NERVES_FW_PRODUCT, "Nerves Vultr Image")
define(NERVES_FW_DESCRIPTION, "")
define(NERVES_FW_VERSION, "${NERVES_SDK_VERSION}")
define(NERVES_FW_PLATFORM, "vultr")
define(NERVES_FW_ARCHITECTURE, "x86_64")
define(NERVES_FW_AUTHOR, "The Nerves Team")

define(NERVES_FW_DEVPATH, "/dev/vda")
define(NERVES_FW_APPLICATION_PART0_DEVPATH, "/dev/vda4") # Linux part number is 1-based
define(NERVES_FW_APPLICATION_PART0_FSTYPE, "ext4")
define(NERVES_FW_APPLICATION_PART0_TARGET, "/root")
define(NERVES_PROVISIONING, "${NERVES_SYSTEM}/images/fwup_include/provisioning.conf")

# Default paths if not specified via the commandline
define(ROOTFS, "${NERVES_SYSTEM}/images/rootfs.squashfs")

# This configuration file will create an image that has an MBR and the
# following 3 partitions:
#
# +----------------------------+
# | MBR w/ Grub boot code      |
# +----------------------------+
# | grub.img (<256K)           |
# +----------------------------+
# | Firmware configuration data|
# | (formatted as uboot env)   |
# +----------------------------+
# | Boot partition (FAT32)     |
# | /boot/grub/grub.cfg        |
# | /boot/grub/grubenv         |
# +----------------------------+
# | p2: Rootfs A (squashfs)    |
# +----------------------------+
# | p3: Rootfs B (squashfs)    |
# +----------------------------+
# | p4: Application (ext4)     |
# +----------------------------+

define(UBOOT_ENV_OFFSET, 2048)
define(UBOOT_ENV_COUNT, 16)  # 8 KB

# The boot partition contains the bootloader configuration
# 16 MB should be plenty for now.
define(BOOT_PART_OFFSET, 4096)
define(BOOT_PART_COUNT, 31232)

# Let the rootfs have room to grow up to 256 MiB
define-eval(ROOTFS_A_PART_OFFSET, "${BOOT_PART_OFFSET} + ${BOOT_PART_COUNT}")
define(ROOTFS_A_PART_COUNT, 524288)
define-eval(ROOTFS_B_PART_OFFSET, "${ROOTFS_A_PART_OFFSET} + ${ROOTFS_A_PART_COUNT}")
define(ROOTFS_B_PART_COUNT, ${ROOTFS_A_PART_COUNT})

# Application data partition (10 GiB). This can be enlarged
# to fill the entire volume.
define-eval(APP_PART_OFFSET, "${ROOTFS_B_PART_OFFSET} + ${ROOTFS_B_PART_COUNT}")
define(APP_PART_COUNT, 20971520)

# Firmware archive metadata
meta-product = ${NERVES_FW_PRODUCT}
meta-description = ${NERVES_FW_DESCRIPTION}
meta-version = ${NERVES_FW_VERSION}
meta-platform = ${NERVES_FW_PLATFORM}
meta-architecture = ${NERVES_FW_ARCHITECTURE}
meta-author = ${NERVES_FW_AUTHOR}
meta-vcs-identifier = ${NERVES_FW_VCS_IDENTIFIER}
meta-misc = ${NERVES_FW_MISC}

# File resources are listed in the order that they are included in the .fw file
# This is important, since this is the order that they're written on a firmware
# update due to the event driven nature of the update system.
file-resource grub.img {
    host-path = "${NERVES_SYSTEM}/images/grub.img"
}
file-resource grub.cfg {
    host-path = "${NERVES_SYSTEM}/images/grub.cfg"
}

# Order the rootfs image before the grub environment resources
# so that the grub environment blobs get written last. This
# is in case the user aborts the programming midway.
file-resource rootfs.img {
    host-path = ${ROOTFS}

    # Error out if the rootfs size exceeds the partition size
    assert-size-lte = ${ROOTFS_A_PART_COUNT}
}
file-resource grubenv_a_valid {
    host-path = "${NERVES_SYSTEM}/images/grubenv_a_valid"
}
file-resource grubenv_a {
    host-path = "${NERVES_SYSTEM}/images/grubenv_a"
}
file-resource grubenv_b {
    host-path = "${NERVES_SYSTEM}/images/grubenv_b"
}

mbr mbr {
    bootstrap-code-host-path = "${NERVES_SYSTEM}/images/boot.img"
    partition 0 {
        block-offset = ${BOOT_PART_OFFSET}
        block-count = ${BOOT_PART_COUNT}
        type = 0xc # FAT32
        boot = true
    }
    partition 1 {
        block-offset = ${ROOTFS_A_PART_OFFSET}
        block-count = ${ROOTFS_A_PART_COUNT}
        type = 0x83 # Linux
    }
    partition 2 {
        block-offset = ${ROOTFS_B_PART_OFFSET}
        block-count = ${ROOTFS_B_PART_COUNT}
        type = 0x83 # Linux
    }
    partition 3 {
        block-offset = ${APP_PART_OFFSET}
        block-count = ${APP_PART_COUNT}
        type = 0x83 # Linux
        expand = true
    }
}

# Location where installed firmware information is stored.
# While this is called "u-boot", u-boot isn't involved in this
# setup. It just provides a convenient key/value store format.
uboot-environment uboot-env {
    block-offset = ${UBOOT_ENV_OFFSET}
    block-count = ${UBOOT_ENV_COUNT}
}

# This firmware task writes everything to the destination media.
# This should only be run for the first installation.
task complete {
    # Only match if not mounted
    require-unmounted-destination = true

    on-init {
        mbr_write(mbr)

        fat_mkfs(${BOOT_PART_OFFSET}, ${BOOT_PART_COUNT})
        fat_mkdir(${BOOT_PART_OFFSET}, "/boot")
        fat_mkdir(${BOOT_PART_OFFSET}, "/boot/grub")

        uboot_clearenv(uboot-env)

        include("${NERVES_PROVISIONING}")

        uboot_setenv(uboot-env, "nerves_fw_active", "a")
        uboot_setenv(uboot-env, "nerves_fw_devpath", ${NERVES_FW_DEVPATH})
        uboot_setenv(uboot-env, "a.nerves_fw_application_part0_devpath", ${NERVES_FW_APPLICATION_PART0_DEVPATH})
        uboot_setenv(uboot-env, "a.nerves_fw_application_part0_fstype", ${NERVES_FW_APPLICATION_PART0_FSTYPE})
        uboot_setenv(uboot-env, "a.nerves_fw_application_part0_target", ${NERVES_FW_APPLICATION_PART0_TARGET})
        uboot_setenv(uboot-env, "a.nerves_fw_product", ${NERVES_FW_PRODUCT})
        uboot_setenv(uboot-env, "a.nerves_fw_description", ${NERVES_FW_DESCRIPTION})
        uboot_setenv(uboot-env, "a.nerves_fw_version", ${NERVES_FW_VERSION})
        uboot_setenv(uboot-env, "a.nerves_fw_platform", ${NERVES_FW_PLATFORM})
        uboot_setenv(uboot-env, "a.nerves_fw_architecture", ${NERVES_FW_ARCHITECTURE})
        uboot_setenv(uboot-env, "a.nerves_fw_author", ${NERVES_FW_AUTHOR})
        uboot_setenv(uboot-env, "a.nerves_fw_vcs_identifier", ${NERVES_FW_VCS_IDENTIFIER})
        uboot_setenv(uboot-env, "a.nerves_fw_misc", ${NERVES_FW_MISC})
        uboot_setenv(uboot-env, "a.nerves_fw_uuid", "\${FWUP_META_UUID}")
    }

    on-resource grub.img { raw_write(1) }
    on-resource grub.cfg { fat_write(${BOOT_PART_OFFSET}, "/boot/grub/grub.cfg") }
    on-resource grubenv_a_valid { fat_write(${BOOT_PART_OFFSET}, "/boot/grub/grubenv") }

    on-resource rootfs.img {
        # write to the first rootfs partition
        raw_write(${ROOTFS_A_PART_OFFSET})
    }

    on-finish {
        # Clear out any old data in the B partition that might be mistaken for
        # a file system. This is mostly to avoid confusion in humans when
        # reprogramming SDCards with unknown contents.
        raw_memset(${ROOTFS_B_PART_OFFSET}, 256, 0xff)

        # Invalidate the application data partition so that it is guaranteed to
        # trigger the corrupt filesystem detection code on first boot and get
        # formatted.
        raw_memset(${APP_PART_OFFSET}, 256, 0xff)
    }
}

task upgrade.a {
    # This task upgrades the A partition, so make sure we're running
    # on B.
    require-path-on-device("/", "/dev/vda3")

    # Verify the expected platform/architecture
    require-uboot-variable(uboot-env, "b.nerves_fw_platform", "${NERVES_FW_PLATFORM}")
    require-uboot-variable(uboot-env, "b.nerves_fw_architecture", "${NERVES_FW_ARCHITECTURE}")

    on-init {
        info("Upgrading partition A")

        # Clear some firmware information just in case this update gets
        # interrupted midway. If this partition was bootable, it's not going to
        # be soon.
        uboot_unsetenv(uboot-env, "a.nerves_fw_version")
        uboot_unsetenv(uboot-env, "a.nerves_fw_platform")
        uboot_unsetenv(uboot-env, "a.nerves_fw_architecture")
        uboot_unsetenv(uboot-env, "a.nerves_fw_uuid")

        # Indicate that the entire partition can be cleared
        trim(${ROOTFS_A_PART_OFFSET}, ${ROOTFS_A_PART_COUNT})
    }

    on-resource rootfs.img {
        raw_write(${ROOTFS_A_PART_OFFSET})
    }

    # Key step to switching over the A partition
    on-resource grubenv_a {
        # Update firmware metadata
        uboot_setenv(uboot-env, "a.nerves_fw_application_part0_devpath", ${NERVES_FW_APPLICATION_PART0_DEVPATH})
        uboot_setenv(uboot-env, "a.nerves_fw_application_part0_fstype", ${NERVES_FW_APPLICATION_PART0_FSTYPE})
        uboot_setenv(uboot-env, "a.nerves_fw_application_part0_target", ${NERVES_FW_APPLICATION_PART0_TARGET})
        uboot_setenv(uboot-env, "a.nerves_fw_product", ${NERVES_FW_PRODUCT})
        uboot_setenv(uboot-env, "a.nerves_fw_description", ${NERVES_FW_DESCRIPTION})
        uboot_setenv(uboot-env, "a.nerves_fw_version", ${NERVES_FW_VERSION})
        uboot_setenv(uboot-env, "a.nerves_fw_platform", ${NERVES_FW_PLATFORM})
        uboot_setenv(uboot-env, "a.nerves_fw_architecture", ${NERVES_FW_ARCHITECTURE})
        uboot_setenv(uboot-env, "a.nerves_fw_author", ${NERVES_FW_AUTHOR})
        uboot_setenv(uboot-env, "a.nerves_fw_vcs_identifier", ${NERVES_FW_VCS_IDENTIFIER})
        uboot_setenv(uboot-env, "a.nerves_fw_misc", ${NERVES_FW_MISC})
        uboot_setenv(uboot-env, "a.nerves_fw_uuid", "\${FWUP_META_UUID}")

	# Switch over to boot the new firmware
        uboot_setenv(uboot-env, "nerves_fw_active", "a")
        fat_write(${BOOT_PART_OFFSET}, "/boot/grub/grubenv")
    }

    on-finish {
    }
}

task upgrade.b {
    # This task upgrades the B partition, so make sure we're running
    # on A.
    require-path-on-device("/", "/dev/vda2")

    # Verify the expected platform/architecture
    require-uboot-variable(uboot-env, "a.nerves_fw_platform", "${NERVES_FW_PLATFORM}")
    require-uboot-variable(uboot-env, "a.nerves_fw_architecture", "${NERVES_FW_ARCHITECTURE}")

    on-init {
        info("Upgrading partition B")

        # Clear some firmware information just in case this update gets
        # interrupted midway.
        uboot_unsetenv(uboot-env, "b.nerves_fw_version")
        uboot_unsetenv(uboot-env, "b.nerves_fw_platform")
        uboot_unsetenv(uboot-env, "b.nerves_fw_architecture")
        uboot_unsetenv(uboot-env, "b.nerves_fw_uuid")

        trim(${ROOTFS_B_PART_OFFSET}, ${ROOTFS_B_PART_COUNT})
    }

    on-resource rootfs.img {
        raw_write(${ROOTFS_B_PART_OFFSET})
    }

    # Key step to switching over the B partition
    on-resource grubenv_b {
        # Update firmware metadata
        uboot_setenv(uboot-env, "b.nerves_fw_application_part0_devpath", ${NERVES_FW_APPLICATION_PART0_DEVPATH})
        uboot_setenv(uboot-env, "b.nerves_fw_application_part0_fstype", ${NERVES_FW_APPLICATION_PART0_FSTYPE})
        uboot_setenv(uboot-env, "b.nerves_fw_application_part0_target", ${NERVES_FW_APPLICATION_PART0_TARGET})
        uboot_setenv(uboot-env, "b.nerves_fw_product", ${NERVES_FW_PRODUCT})
        uboot_setenv(uboot-env, "b.nerves_fw_description", ${NERVES_FW_DESCRIPTION})
        uboot_setenv(uboot-env, "b.nerves_fw_version", ${NERVES_FW_VERSION})
        uboot_setenv(uboot-env, "b.nerves_fw_platform", ${NERVES_FW_PLATFORM})
        uboot_setenv(uboot-env, "b.nerves_fw_architecture", ${NERVES_FW_ARCHITECTURE})
        uboot_setenv(uboot-env, "b.nerves_fw_author", ${NERVES_FW_AUTHOR})
        uboot_setenv(uboot-env, "b.nerves_fw_vcs_identifier", ${NERVES_FW_VCS_IDENTIFIER})
        uboot_setenv(uboot-env, "b.nerves_fw_misc", ${NERVES_FW_MISC})
        uboot_setenv(uboot-env, "b.nerves_fw_uuid", "\${FWUP_META_UUID}")

	# Switch over to boot the new firmware
        uboot_setenv(uboot-env, "nerves_fw_active", "b")
        fat_write(${BOOT_PART_OFFSET}, "/boot/grub/grubenv")
    }

    on-finish {
    }
}

task upgrade.unexpected {
    require-uboot-variable(uboot-env, "a.nerves_fw_platform", "${NERVES_FW_PLATFORM}")
    require-uboot-variable(uboot-env, "a.nerves_fw_architecture", "${NERVES_FW_ARCHITECTURE}")
    on-init {
        error("Please check the media being upgraded. It doesn't look like either the A or B partitions are active.")
    }
}

task upgrade.wrongplatform {
    on-init {
        error("Expecting platform=${NERVES_FW_PLATFORM} and architecture=${NERVES_FW_ARCHITECTURE}")
    }
}

task provision {
    require-uboot-variable(uboot-env, "a.nerves_fw_platform", "${NERVES_FW_PLATFORM}")
    require-uboot-variable(uboot-env, "a.nerves_fw_architecture", "${NERVES_FW_ARCHITECTURE}")
    on-init {
        include("${NERVES_PROVISIONING}")
    }
}
task provision.wrongplatform {
    on-init {
        error("Expecting platform=${NERVES_FW_PLATFORM} and architecture=${NERVES_FW_ARCHITECTURE}")
    }
}