pmbootstrap install --ondev: new option

Add initial support for the on-device installer in pmbootstrap. Let
pmbootstrap create a regular split image, then prepare a new installer
rootfs and copy the previously generated rootfs image into the installer
rootfs. Put the installer rootfs into a new image, with reserved space.

There is more to do from here, such as disabling the generation of the
user account when using --ondev. But this requires support in
postmarketos-ondev first, so let's build that iteratively.

Related: https://wiki.postmarketos.org/wiki/On-device_installer
Related: https://gitlab.com/postmarketOS/postmarketos-ondev/-/issues

pmb/chroot/shutdown.py

@@ -67,10 +67,11 @@ def shutdown(args, only_install_related=False):
             path = path_outside[len(chroot):]
             pmb.install.losetup.umount(args, path, auto_init=False)
 
-    # Umount device rootfs chroot
-    chroot_rootfs = args.work + "/chroot_rootfs_" + args.device
-    if os.path.exists(chroot_rootfs):
-        pmb.helpers.mount.umount_all(args, chroot_rootfs)
+    # Umount device rootfs and installer chroots
+    for prefix in ["rootfs", "installer"]:
+        path = f"{args.work}/chroot_{prefix}_{args.device}"
+        if os.path.exists(path):
+            pmb.helpers.mount.umount_all(args, path)
 
     if not only_install_related:
         # Umount all folders inside args.work

pmb/chroot/zap.py

@@ -53,6 +53,7 @@ def zap(args, confirm=True, dry=False, pkgs_local=False, http=False,
     patterns = [
         "chroot_native",
         "chroot_buildroot_*",
+        "chroot_installer_*",
         "chroot_rootfs_*",
     ]
     if pkgs_local:

pmb/helpers/frontend.py

@@ -25,6 +25,7 @@ import pmb.helpers.run
 import pmb.helpers.aportupgrade
 import pmb.helpers.status
 import pmb.install
+import pmb.install.blockdevice
 import pmb.parse
 import pmb.qemu
 
@@ -132,6 +133,14 @@ def chroot(args):
         env["DISPLAY"] = os.environ.get("DISPLAY")
         env["XAUTHORITY"] = "/home/pmos/.Xauthority"
 
+    # Install blockdevice
+    if args.install_blockdev:
+        size_boot = 128  # 128 MB
+        size_root = 4096  # 4 GB
+        size_reserve = 2048  # 2 GB
+        pmb.install.blockdevice.create_and_mount_image(args, size_boot,
+                                                       size_root, size_reserve)
+
     # Run the command as user/root
     if args.user:
         logging.info("(" + suffix + ") % su pmos -c '" +
@@ -195,6 +204,24 @@ def install(args):
     if args.rsync and not args.sdcard:
         raise ValueError("Installation using rsync only works on sdcard.")
 
+    # On-device installer checks
+    # Note that this can't be in the mutually exclusive group that has most of
+    # the conflicting options, because then it would not work with --sdcard.
+    if args.on_device_installer:
+        if args.full_disk_encryption:
+            raise ValueError("--on-device-installer cannot be combined with"
+                             " --fde. The user can choose to encrypt their"
+                             " installation later in the on-device installer.")
+        if args.android_recovery_zip:
+            raise ValueError("--on-device-installer cannot be combined with"
+                             " --android-recovery-zip (patches welcome)")
+        if args.no_image:
+            raise ValueError("--on-device-installer cannot be combined with"
+                             " --no-image")
+        if args.rsync:
+            raise ValueError("--on-device-installer cannot be combined with"
+                             " --rsync")
+
     if not args.sdcard and args.split is None:
         # Default to split if the flash method requires it
         flasher = pmb.config.flashers.get(args.deviceinfo["flash_method"], {})

pmb/install/_install.py

@@ -11,6 +11,7 @@ import pmb.chroot.apk
 import pmb.chroot.other
 import pmb.chroot.initfs
 import pmb.config
+import pmb.config.pmaports
 import pmb.helpers.devices
 import pmb.helpers.run
 import pmb.install.blockdevice
@@ -19,32 +20,38 @@ import pmb.install.recovery
 import pmb.install
 
 
-def mount_device_rootfs(args, suffix="native"):
+def mount_device_rootfs(args, suffix_rootfs, suffix_mount="native"):
     """
     Mount the device rootfs.
+    :param suffix_rootfs: the chroot suffix, where the rootfs that will be
+                          installed on the device has been created (e.g.
+                          "rootfs_qemu-amd64")
+    :param suffix_mount: the chroot suffix, where the device rootfs will be
+                         mounted (e.g. "native")
     """
-    mountpoint = "/mnt/rootfs_" + args.device
-    pmb.helpers.mount.bind(args, args.work + "/chroot_rootfs_" + args.device,
-                           args.work + "/chroot_" + suffix + mountpoint)
+    mountpoint = f"/mnt/{suffix_rootfs}"
+    pmb.helpers.mount.bind(args, f"{args.work}/chroot_{suffix_rootfs}",
+                           f"{args.work}/chroot_{suffix_mount}{mountpoint}")
     return mountpoint
 
 
-def get_subpartitions_size(args):
+def get_subpartitions_size(args, suffix):
     """
     Calculate the size of the boot and root subpartition.
 
+    :param suffix: the chroot suffix, e.g. "rootfs_qemu-amd64"
     :returns: (boot, root) the size of the boot and root
-              partition as integer in bytes
+              partition as integer in MB
     """
-    boot = int(args.boot_size) * 1024 * 1024
+    boot = int(args.boot_size)
 
     # Estimate root partition size, then add some free space. The size
     # calculation is not as trivial as one may think, and depending on the
     # file system etc it seems to be just impossible to get it right.
-    chroot = args.work + "/chroot_rootfs_" + args.device
-    root = pmb.helpers.other.folder_size(args, chroot)
+    chroot = f"{args.work}/chroot_{suffix}"
+    root = pmb.helpers.other.folder_size(args, chroot) / 1024 / 1024
     root *= 1.20
-    root += 50 * 1024 * 1024
+    root += 50
     return (boot, root)
 
 
@@ -94,16 +101,17 @@ def get_kernel_package(args, device):
     return ["device-" + device + "-kernel-" + args.kernel]
 
 
-def copy_files_from_chroot(args):
+def copy_files_from_chroot(args, suffix):
     """
     Copy all files from the rootfs chroot to /mnt/install, except
     for the home folder (because /home will contain some empty
     mountpoint folders).
+
+    :param suffix: the chroot suffix, e.g. "rootfs_qemu-amd64"
     """
     # Mount the device rootfs
-    logging.info("(native) copy rootfs_" + args.device + " to" +
-                 " /mnt/install/")
-    mountpoint = mount_device_rootfs(args)
+    logging.info(f"(native) copy {suffix} to /mnt/install/")
+    mountpoint = mount_device_rootfs(args, suffix)
     mountpoint_outside = args.work + "/chroot_native" + mountpoint
 
     # Remove empty qemu-user binary stub (where the binary was bind-mounted)
@@ -303,7 +311,7 @@ def embed_firmware(args):
                                "deviceinfo_sd_embed_firmware_step_size "
                                "is not valid: {}".format(step))
 
-    device_rootfs = mount_device_rootfs(args)
+    device_rootfs = mount_device_rootfs(args, f"rootfs_{args.device}")
     binaries = args.deviceinfo["sd_embed_firmware"].split(",")
 
     # Perform three checks prior to writing binaries to disk: 1) that binaries
@@ -366,31 +374,36 @@ def sanity_check_sdcard(device):
             raise RuntimeError("{} is read-only, is the sdcard locked?".format(device))
 
 
-def install_system_image(args):
+def install_system_image(args, size_reserve, suffix, root_label="pmOS_root",
+                         step=3, steps=5, split=False, sdcard=None):
+    """
+    :param size_reserve: empty partition between root and boot in MB (pma#463)
+    :param suffix: the chroot suffix, where the rootfs that will be installed
+                   on the device has been created (e.g. "rootfs_qemu-amd64")
+    :param root_label: label of the root partition (e.g. "pmOS_root")
+    :param step: next installation step
+    :param steps: total installation steps
+    :param split: create separate images for boot and root partitions
+    :param sdcard: path to sdcard device (e.g. /dev/mmcblk0) or None
+    """
     # Partition and fill image/sdcard
-    logging.info("*** (3/5) PREPARE INSTALL BLOCKDEVICE ***")
+    logging.info(f"*** ({step}/{steps}) PREPARE INSTALL BLOCKDEVICE ***")
     pmb.chroot.shutdown(args, True)
-    (size_boot, size_root) = get_subpartitions_size(args)
+    (size_boot, size_root) = get_subpartitions_size(args, suffix)
     if not args.rsync:
-        pmb.install.blockdevice.create(args, size_boot, size_root)
-        if not args.split:
-            pmb.install.partition(args, size_boot)
-    if not args.split:
-        pmb.install.partitions_mount(args)
+        pmb.install.blockdevice.create(args, size_boot, size_root,
+                                       size_reserve, split, sdcard)
+        if not split:
+            pmb.install.partition(args, size_boot, size_reserve)
+    if not split:
+        root_id = 3 if size_reserve else 2
+        pmb.install.partitions_mount(args, root_id, sdcard)
 
-    if args.full_disk_encryption:
-        logging.info("WARNING: Full disk encryption is enabled!")
-        logging.info("Make sure that osk-sdl has been properly configured for your device")
-        logging.info("or else you will be unable to unlock the rootfs on boot!")
-        logging.info("If you started a device port, it is recommended you disable")
-        logging.info("FDE by re-running the install command without '--fde' until")
-        logging.info("you have properly configured osk-sdl. More information:")
-        logging.info("<https://postmarketos.org/osk-port>")
-    pmb.install.format(args)
+    pmb.install.format(args, size_reserve, root_label, sdcard)
 
     # Just copy all the files
-    logging.info("*** (4/5) FILL INSTALL BLOCKDEVICE ***")
-    copy_files_from_chroot(args)
+    logging.info(f"*** ({step + 1}/{steps}) FILL INSTALL BLOCKDEVICE ***")
+    copy_files_from_chroot(args, suffix)
     create_home_from_skel(args)
     configure_apk(args)
     copy_ssh_keys(args)
@@ -402,7 +415,7 @@ def install_system_image(args):
     if sparse is None:
         sparse = args.deviceinfo["flash_sparse"] == "true"
 
-    if sparse and not args.split and not args.sdcard:
+    if sparse and not split and not sdcard:
         logging.info("(native) make sparse rootfs")
         pmb.chroot.apk.install(args, ["android-tools"])
         sys_image = args.device + ".img"
@@ -412,8 +425,13 @@ def install_system_image(args):
         pmb.chroot.user(args, ["mv", "-f", sys_image_sparse, sys_image],
                         working_dir="/home/pmos/rootfs/")
 
-    # Kernel flash information
-    logging.info("*** (5/5) FLASHING TO DEVICE ***")
+
+def print_flash_info(args, step=5):
+    """ Print flashing information, based on the deviceinfo data and the
+        pmbootstrap arguments.
+
+        :param step: installation step number """
+    logging.info(f"*** ({step}/{step}) FLASHING TO DEVICE ***")
     logging.info("Run the following to flash your installation to the"
                  " target device:")
 
@@ -428,16 +446,18 @@ def install_system_image(args):
         logging.info("* pmbootstrap flasher flash_rootfs")
         logging.info("  Flashes the generated rootfs image to your device:")
         if args.split:
-            logging.info("  " + args.work + "/chroot_native/home/pmos/rootfs/" +
-                         args.device + "-rootfs.img")
+            logging.info(f"  {args.work}/chroot_native/home/pmos/rootfs/"
+                         f"{args.device}-rootfs.img")
         else:
-            logging.info("  " + args.work + "/chroot_native/home/pmos/rootfs/" +
-                         args.device + ".img")
-            logging.info("  (NOTE: This file has a partition table, which contains"
-                         " /boot and / subpartitions. That way we don't need to"
-                         " change the partition layout on your device.)")
+            logging.info(f"  {args.work}/chroot_native/home/pmos/rootfs/"
+                         f"{args.device}.img")
+            logging.info("  (NOTE: This file has a partition table, which"
+                         " contains /boot and / subpartitions. That way we"
+                         " don't need to change the partition layout on your"
+                         " device.)")
 
-    # if current flasher supports vbmeta and partition is explicitly spcified in deviceinfo
+    # if current flasher supports vbmeta and partition is explicitly specified
+    # in deviceinfo
     if "flash_vbmeta" in flasher_actions and \
             (args.deviceinfo["flash_fastboot_partition_vbmeta"] or
              args.deviceinfo["flash_heimdall_partition_vbmeta"]):
@@ -448,14 +468,15 @@ def install_system_image(args):
     # (e.g. an Android boot image is generated). In that case, "flash_kernel"
     # works even when partitions are split or installing for sdcard.
     # This is not possible if the flash method requires split partitions.
-    if "flash_kernel" in flasher_actions and (not requires_split or args.split):
+    if "flash_kernel" in flasher_actions and \
+            (not requires_split or args.split):
         logging.info("* pmbootstrap flasher flash_kernel")
         logging.info("  Flashes the kernel + initramfs to your device:")
         if requires_split:
-            logging.info("  " + args.work + "/chroot_native/home/pmos/rootfs/" +
-                         args.device + "-boot.img")
+            logging.info(f"  {args.work}/chroot_native/home/pmos/rootfs/"
+                         f"{args.device}-boot.img")
         else:
-            logging.info("  " + args.work + "/chroot_rootfs_" + args.device + "/boot")
+            logging.info(f"  {args.work}/chroot_rootfs_{args.device}/boot")
 
     if "boot" in flasher_actions:
         logging.info("  (NOTE: " + method + " also supports booting"
@@ -471,7 +492,7 @@ def install_system_image(args):
 def install_recovery_zip(args):
     logging.info("*** (3/4) CREATING RECOVERY-FLASHABLE ZIP ***")
     suffix = "buildroot_" + args.deviceinfo["arch"]
-    mount_device_rootfs(args, suffix)
+    mount_device_rootfs(args, f"rootfs_{args.device}", suffix)
     pmb.install.recovery.create_zip(args, suffix)
 
     # Flash information
@@ -480,6 +501,56 @@ def install_recovery_zip(args):
     logging.info("<https://postmarketos.org/recoveryzip>")
 
 
+def install_on_device_installer(args, step, steps):
+    # Generate the rootfs image
+    suffix_rootfs = f"rootfs_{args.device}"
+    install_system_image(args, 0, suffix_rootfs, step=step, steps=steps,
+                         split=True)
+    step += 2
+
+    # Prepare the installer chroot
+    logging.info(f"*** ({step}/{steps}) CREATE ON-DEVICE INSTALLER ROOTFS ***")
+    step += 1
+    packages = ([f"device-{args.device}",
+                 "postmarketos-ondev"] +
+                get_kernel_package(args, args.device) +
+                get_nonfree_packages(args, args.device))
+    suffix_installer = f"installer_{args.device}"
+    pmb.chroot.apk.install(args, packages, suffix_installer)
+
+    # Move rootfs image into installer chroot
+    img = f"{args.device}-root.img"
+    img_path_src = f"{args.work}/chroot_native/home/pmos/rootfs/{img}"
+    img_path_dest = f"{args.work}/chroot_{suffix_installer}/var/lib/rootfs.img"
+    logging.info(f"({suffix_installer}) add {img} as /var/lib/rootfs.img")
+    pmb.install.losetup.umount(args, img_path_src)
+    pmb.helpers.run.root(args, ["mv", img_path_src, img_path_dest])
+
+    # Run ondev-prepare, so it may generate nice configs from the channel
+    # properties (e.g. to display the version number), or transform the image
+    # file into another format. This can all be done without pmbootstrap
+    # changes in the postmarketos-ondev package.
+    logging.info(f"({suffix_installer}) ondev-prepare-image")
+    channel = pmb.config.pmaports.read_config(args)["channel"]
+    channel_cfg = pmb.config.pmaports.read_config_channel(args)
+    pmb.chroot.root(args, ["ondev-prepare", channel,
+                           channel_cfg["description"],
+                           channel_cfg["branch_pmaports"],
+                           channel_cfg["branch_aports"],
+                           channel_cfg["mirrordir_alpine"]], suffix_installer)
+
+    # Remove $DEVICE-boot.img (we will generate a new one if --split was
+    # specified, otherwise the separate boot image is not needed)
+    img_boot = f"{args.device}-boot.img"
+    logging.info(f"(native) rm {img_boot}")
+    pmb.chroot.root(args, ["rm", f"/home/pmos/rootfs/{img_boot}"])
+
+    # Generate installer image
+    size_reserve = round(os.path.getsize(img_path_dest) / 1024 / 1024) + 200
+    install_system_image(args, size_reserve, suffix_installer, "pmOS_install",
+                         step, steps, args.split, args.sdcard)
+
+
 def install(args):
     # Sanity checks
     if not args.android_recovery_zip and args.sdcard:
@@ -490,6 +561,8 @@ def install(args):
         steps = 2
     elif args.android_recovery_zip:
         steps = 4
+    elif args.on_device_installer:
+        steps = 8
     else:
         steps = 5
 
@@ -547,7 +620,15 @@ def install(args):
     # Set the hostname as the device name
     setup_hostname(args)
 
-    if args.android_recovery_zip:
-        install_recovery_zip(args)
-    elif not args.no_image:
-        install_system_image(args)
+    if args.no_image:
+        return
+    elif args.android_recovery_zip:
+        return install_recovery_zip(args)
+
+    if args.on_device_installer:
+        # Runs install_system_image twice
+        install_on_device_installer(args, 3, steps)
+    else:
+        install_system_image(args, 0, f"rootfs_{args.device}",
+                             split=args.split, sdcard=args.sdcard)
+    print_flash_info(args, steps)

pmb/install/blockdevice.py

@@ -9,14 +9,15 @@ import pmb.helpers.cli
 import pmb.config
 
 
-def previous_install(args):
+def previous_install(args, path):
     """
     Search the sdcard for possible existence of a previous installation of pmOS.
     We temporarily mount the possible pmOS_boot partition as /dev/sdcardp1 inside
     the native chroot to check the label from there.
+    :param path: path to sdcard device (e.g. /dev/mmcblk0)
     """
     label = ""
-    for blockdevice_outside in [args.sdcard + "1", args.sdcard + "p1"]:
+    for blockdevice_outside in [f"{path}1", f"{path}p1"]:
         if not os.path.exists(blockdevice_outside):
             continue
         blockdevice_inside = "/dev/sdcardp1"
@@ -28,39 +29,45 @@ def previous_install(args):
     return "pmOS_boot" in label
 
 
-def mount_sdcard(args):
+def mount_sdcard(args, path):
+    """
+    :param path: path to sdcard device (e.g. /dev/mmcblk0)
+    """
     # Sanity checks
     if args.deviceinfo["external_storage"] != "true":
         raise RuntimeError("According to the deviceinfo, this device does"
                            " not support a sdcard installation.")
-    if not os.path.exists(args.sdcard):
-        raise RuntimeError("The sdcard device does not exist: " +
-                           args.sdcard)
-    for path in glob.glob(args.sdcard + "*"):
-        if pmb.helpers.mount.ismount(path):
-            raise RuntimeError(path + " is mounted! We will not attempt"
-                               " to format this!")
-    logging.info("(native) mount /dev/install (host: " + args.sdcard + ")")
-    pmb.helpers.mount.bind_file(args, args.sdcard,
+    if not os.path.exists(path):
+        raise RuntimeError(f"The sdcard device does not exist: {path}")
+    for path_mount in glob.glob(f"{path}*"):
+        if pmb.helpers.mount.ismount(path_mount):
+            raise RuntimeError(f"{path_mount} is mounted! Will not attempt to"
+                               " format this!")
+    logging.info(f"(native) mount /dev/install (host: {path})")
+    pmb.helpers.mount.bind_file(args, path,
                                 args.work + "/chroot_native/dev/install")
-    if previous_install(args):
+    if previous_install(args, path):
         if not pmb.helpers.cli.confirm(args, "WARNING: This device has a"
                                        " previous installation of pmOS."
                                        " CONTINUE?"):
             raise RuntimeError("Aborted.")
     else:
-        if not pmb.helpers.cli.confirm(args, "EVERYTHING ON " + args.sdcard +
-                                       " WILL BE ERASED! CONTINUE?"):
+        if not pmb.helpers.cli.confirm(args, f"EVERYTHING ON {path} WILL BE"
+                                       " ERASED! CONTINUE?"):
             raise RuntimeError("Aborted.")
 
 
-def create_and_mount_image(args, size_boot, size_root):
+def create_and_mount_image(args, size_boot, size_root, size_reserve,
+                           split=False):
     """
     Create a new image file, and mount it as /dev/install.
 
-    :param size_boot: size of the boot partition in bytes
-    :param size_root: size of the root partition in bytes
+    :param size_boot: size of the boot partition in MB
+    :param size_root: size of the root partition in MB
+    :param size_reserve: empty partition between root and boot in MB (pma#463)
+    :param split: create separate images for boot and root partitions
     """
+
     # Short variables for paths
     chroot = args.work + "/chroot_native"
     img_path_prefix = "/home/pmos/rootfs/" + args.device
@@ -77,7 +84,7 @@ def create_and_mount_image(args, size_boot, size_root):
             pmb.chroot.root(args, ["rm", img_path])
 
     # Make sure there is enough free space
-    size_mb = round((size_boot + size_root) / (1024**2))
+    size_mb = round(size_boot + size_reserve + size_root)
     disk_data = os.statvfs(args.work)
     free = round((disk_data.f_bsize * disk_data.f_bavail) / (1024**2))
     if size_mb > free:
@@ -86,10 +93,10 @@ def create_and_mount_image(args, size_boot, size_root):
     # Create empty image files
     pmb.chroot.user(args, ["mkdir", "-p", "/home/pmos/rootfs"])
     size_mb_full = str(size_mb) + "M"
-    size_mb_boot = str(round(size_boot / (1024**2))) + "M"
-    size_mb_root = str(round(size_root / (1024**2))) + "M"
+    size_mb_boot = str(round(size_boot)) + "M"
+    size_mb_root = str(round(size_root)) + "M"
     images = {img_path_full: size_mb_full}
-    if args.split:
+    if split:
         images = {img_path_boot: size_mb_boot,
                   img_path_root: size_mb_root}
     for img_path, size_mb in images.items():
@@ -98,7 +105,7 @@ def create_and_mount_image(args, size_boot, size_root):
 
     # Mount to /dev/install
     mount_image_paths = {img_path_full: "/dev/install"}
-    if args.split:
+    if split:
         mount_image_paths = {img_path_boot: "/dev/installp1",
                              img_path_root: "/dev/installp2"}
 
@@ -111,16 +118,20 @@ def create_and_mount_image(args, size_boot, size_root):
                                     args.work + "/chroot_native" + mount_point)
 
 
-def create(args, size_boot, size_root):
+def create(args, size_boot, size_root, size_reserve, split, sdcard):
     """
     Create /dev/install (the "install blockdevice").
 
-    :param size_boot: size of the boot partition in bytes
-    :param size_root: size of the root partition in bytes
+    :param size_boot: size of the boot partition in MB
+    :param size_root: size of the root partition in MB
+    :param size_reserve: empty partition between root and boot in MB (pma#463)
+    :param split: create separate images for boot and root partitions
+    :param sdcard: path to sdcard device (e.g. /dev/mmcblk0) or None
     """
     pmb.helpers.mount.umount_all(
         args, args.work + "/chroot_native/dev/install")
-    if args.sdcard:
-        mount_sdcard(args)
+    if sdcard:
+        mount_sdcard(args, sdcard)
     else:
-        create_and_mount_image(args, size_boot, size_root)
+        create_and_mount_image(args, size_boot, size_root, size_reserve,
+                               split)

pmb/install/format.py

@@ -23,9 +23,11 @@ def format_and_mount_boot(args):
     pmb.chroot.root(args, ["mount", device, mountpoint])
 
 
-def format_and_mount_root(args):
+def format_and_mount_root(args, device):
+    """
+    :param device: root partition on install block device (e.g. /dev/installp2)
+    """
     mountpoint = "/dev/mapper/pm_crypt"
-    device = "/dev/installp2"
     if args.full_disk_encryption:
         logging.info("(native) format " + device + " (root, luks), mount to " +
                      mountpoint)
@@ -41,12 +43,15 @@ def format_and_mount_root(args):
             raise RuntimeError("Failed to open cryptdevice!")
 
 
-def format_and_mount_pm_crypt(args):
+def format_and_mount_pm_crypt(args, device, root_label, sdcard):
+    """
+    :param device: root partition on install block device (e.g. /dev/installp2)
+    :param root_label: label of the root partition (e.g. "pmOS_root")
+    :param sdcard: path to sdcard device (e.g. /dev/mmcblk0) or None
+    """
     # Block device
     if args.full_disk_encryption:
         device = "/dev/mapper/pm_crypt"
-    else:
-        device = "/dev/installp2"
 
     # Format
     if not args.rsync:
@@ -55,12 +60,12 @@ def format_and_mount_pm_crypt(args):
         # When changing the options of mkfs.ext4, also change them in the
         # recovery zip code (see 'grep -r mkfs\.ext4')!
         mkfs_ext4_args = ["mkfs.ext4", "-O", "^metadata_csum", "-F",
-                          "-q", "-L", "pmOS_root"]
+                          "-q", "-L", root_label]
 
         # When we don't know the file system size before hand like
         # with non-block devices, we need to explicitely set a number of
         # inodes. See #1717 and #1845 for details
-        if not args.sdcard:
+        if not sdcard:
             mkfs_ext4_args = mkfs_ext4_args + ["-N", "100000"]
 
         pmb.chroot.root(args, mkfs_ext4_args + [device])
@@ -72,7 +77,13 @@ def format_and_mount_pm_crypt(args):
     pmb.chroot.root(args, ["mount", device, mountpoint])
 
 
-def format(args):
-    format_and_mount_root(args)
-    format_and_mount_pm_crypt(args)
+def format(args, size_reserve, root_label, sdcard):
+    """
+    :param size_reserve: empty partition between root and boot in MB (pma#463)
+    :param root_label: label of the root partition (e.g. "pmOS_root")
+    :param sdcard: path to sdcard device (e.g. /dev/mmcblk0) or None
+    """
+    root_dev = "/dev/installp3" if size_reserve else "/dev/installp2"
+    format_and_mount_root(args, root_dev)
+    format_and_mount_pm_crypt(args, root_dev, root_label, sdcard)
     format_and_mount_boot(args)

pmb/install/partition.py

@@ -8,12 +8,14 @@ import pmb.config
 import pmb.install.losetup
 
 
-def partitions_mount(args):
+def partitions_mount(args, root_id, sdcard):
     """
     Mount blockdevices of partitions inside native chroot
+    :param root_id: root partition id (3 with --reserve-space, otherwise 2)
+    :param sdcard: path to sdcard device (e.g. /dev/mmcblk0) or None
     """
-    prefix = args.sdcard
-    if not args.sdcard:
+    prefix = sdcard
+    if not sdcard:
         img_path = "/home/pmos/rootfs/" + args.device + ".img"
         prefix = pmb.install.losetup.device_by_back_file(args, img_path)
 
@@ -35,22 +37,28 @@ def partitions_mount(args):
                            prefix + " to be located at " + prefix +
                            "1 or " + prefix + "p1!")
 
-    for i in [1, 2]:
+    for i in [1, root_id]:
         source = prefix + partition_prefix + str(i)
         target = args.work + "/chroot_native/dev/installp" + str(i)
         pmb.helpers.mount.bind_file(args, source, target)
 
 
-def partition(args, size_boot):
+def partition(args, size_boot, size_reserve):
     """
-    Partition /dev/install and create /dev/install{p1,p2}
+    Partition /dev/install and create /dev/install{p1,p2,p3}:
+    * /dev/installp1: boot
+    * /dev/installp2: root (or reserved space)
+    * /dev/installp3: (root, if reserved space > 0)
 
-    size_boot: size of the boot partition in bytes.
+    :param size_boot: size of the boot partition in MB
+    :param size_reserve: empty partition between root and boot in MB (pma#463)
     """
     # Convert to MB and print info
-    mb_boot = str(round(size_boot / 1024 / 1024)) + "M"
-    logging.info("(native) partition /dev/install (boot: " + mb_boot +
-                 ", root: the rest)")
+    mb_boot = f"{round(size_boot)}M"
+    mb_reserved = f"{round(size_reserve)}M"
+    mb_root_start = f"{round(size_boot) + round(size_reserve)}M"
+    logging.info(f"(native) partition /dev/install (boot: {mb_boot},"
+                 f" reserved: {mb_reserved}, root: the rest)")
 
     filesystem = args.deviceinfo["boot_filesystem"] or "ext2"
 
@@ -63,9 +71,16 @@ def partition(args, size_boot):
     commands = [
         ["mktable", "msdos"],
         ["mkpart", "primary", filesystem, boot_part_start + 's', mb_boot],
-        ["mkpart", "primary", mb_boot, "100%"],
+    ]
+
+    if size_reserve:
+        commands += [["mkpart", "primary", mb_boot, mb_reserved]]
+
+    commands += [
+        ["mkpart", "primary", mb_root_start, "100%"],
         ["set", "1", "boot", "on"]
     ]
+
     for command in commands:
         pmb.chroot.root(args, ["parted", "-s", "/dev/install"] +
                         command, check=False)

pmb/parse/arch.py

@@ -25,7 +25,7 @@ def alpine_native():
 def from_chroot_suffix(args, suffix):
     if suffix == "native":
         return args.arch_native
-    if suffix == "rootfs_" + args.device:
+    if suffix in [f"rootfs_{args.device}", f"installer_{args.device}"]:
         return args.deviceinfo["arch"]
     if suffix.startswith("buildroot_"):
         return suffix.split("_", 1)[1]

pmb/parse/arguments.py

@@ -497,6 +497,10 @@ def arguments():
                         help="Copy .Xauthority and set environment variables,"
                              " so X11 applications can be started (native"
                              " chroot only)")
+    chroot.add_argument("-i", "--install-blockdev", action="store_true",
+                        help="Create a sparse image file and mount it as"
+                              " /dev/install, just like during the"
+                              " installation process.")
     for action in [build_init, chroot]:
         suffix = action.add_mutually_exclusive_group()
         if action == chroot:
@@ -553,6 +557,11 @@ def arguments():
     install.add_argument("--no-base",
                          help="do not install postmarketos-base (advanced)",
                          action="store_false", dest="install_base")
+    install.add_argument("--on-device-installer", "--ondev",
+                         action="store_true",
+                         help="wrap the resulting image in a graphical"
+                              " on-device installer, so the installation can"
+                              " be customized after flashing")
     group = install.add_mutually_exclusive_group()
     group.add_argument("--sparse", help="generate sparse image file"
                        " (even if unsupported by device)", default=None,