Merge pull request #99 from desultory/dev

Add a separate overlayfs and livegui module

Author: desultory

docs/configuration.md

@@ -26,6 +26,7 @@ Modules write to a shared config dict that is accessible by other modules.
 
 > The main module, mostly pulls basic binaries and pulls the `core`, `mounts`, and `cpio` module.
 
+* `switch_root_target` Set the target filesystem for `switch_root`, defaults to the root mountpoint if not set.
 * `init_target` Sets the init target for `switch_root`.
 * `autodetect_init` (true) Automatically set the init target based `which init`.
 * `loglevel` (5) Sets the kernel log level in the init script.

examples/livegui.toml

@@ -0,0 +1,2 @@
+modules = [ "ugrd.fs.livecd" ]
+livecd_label = "gentoo-amd64-livegui"

src/ugrd/base/base.py

@@ -1,5 +1,5 @@
 __author__ = "desultory"
-__version__ = "5.1.4"
+__version__ = "5.2.0"
 
 from importlib.metadata import version
 from pathlib import Path
@@ -46,12 +46,20 @@ def autodetect_init(self) -> None:
         raise FileNotFoundError("init_target is not specified and could not be detected.")
 
 
+def export_switch_root_target(self) -> None:
+    """Adds SWITCH_ROOT_TARGET to exports.
+    Uses switch_root_target if set, otherwise uses the rootfs."""
+    switch_root_target = self["switch_root_target"]
+    if str(switch_root_target) == ".":  # Handle empty Path
+        switch_root_target = self["mounts"]["root"]["destination"]
+    self["exports"]["SWITCH_ROOT_TARGET"] = switch_root_target
+
 def _find_init(self) -> str:
     """Returns bash to find the init_target."""
     return [
         'for init_path in "/sbin/init" "/bin/init" "/init"; do',
-        '    if [ -e "$(readvar MOUNTS_ROOT_TARGET)$init_path" ] ; then',
-        '        einfo "Found init at: $(readvar MOUNTS_ROOT_TARGET)$init_path"',
+        '    if [ -e "$(readvar SWITCH_ROOT_TARGET)$init_path" ] ; then',
+        '        einfo "Found init at: $(readvar SWITCH_ROOT_TARGET)$init_path"',
         '        setvar init "$init_path"',
         "        return",
         "    fi",
@@ -68,9 +76,8 @@ def set_loglevel(self) -> list[str]:
 
 @contains("init_target", "init_target must be set.", raise_exception=True)
 def do_switch_root(self) -> list[str]:
-    """
-    Should be the final statement, switches root.
-    Checks if the root mount is mounted and that it contains an init.
+    """Should be the final statement, switches root.
+    Checks if the switch_root target is mounted, and that it contains an init.
     If not, it restarts UGRD.
     """
     return [
@@ -79,21 +86,21 @@ def do_switch_root(self) -> list[str]:
         "    exit 1",
         "fi",
         'init_target=$(readvar init) || rd_fail "init_target not set."',  # should be set, if unset, checks fail
-        'einfo "Checking root mount: $(readvar MOUNTS_ROOT_TARGET)"',
-        'if ! grep -q " $(readvar MOUNTS_ROOT_TARGET) " /proc/mounts ; then',
-        '    rd_fail "Root not found at: $(readvar MOUNTS_ROOT_TARGET)"',
-        'elif [ ! -e "$(readvar MOUNTS_ROOT_TARGET)${init_target}" ] ; then',
-        '    ewarn "$init_target not found at: $(readvar MOUNTS_ROOT_TARGET)"',
-        r'    einfo "Target root contents:\n$(ls -l "$(readvar MOUNTS_ROOT_TARGET)")"',
+        'einfo "Checking root mount: $(readvar SWITCH_ROOT_TARGET)"',
+        'if ! grep -q " $(readvar SWITCH_ROOT_TARGET) " /proc/mounts ; then',
+        '    rd_fail "Root not found at: $(readvar SWITCH_ROOT_TARGET)"',
+        'elif [ ! -e "$(readvar SWITCH_ROOT_TARGET)${init_target}" ] ; then',
+        '    ewarn "$init_target not found at: $(readvar SWITCH_ROOT_TARGET)"',
+        r'    einfo "Target root contents:\n$(ls -l "$(readvar SWITCH_ROOT_TARGET)")"',
         "    if _find_init ; then",  # This redefineds the var, so readvar instaed of using $init_target
-        '        einfo "Switching root to: $(readvar MOUNTS_ROOT_TARGET) $(readvar init)"',
-        '        exec switch_root "$(readvar MOUNTS_ROOT_TARGET)" "$(readvar init)"',
+        '        einfo "Switching root to: $(readvar SWITCH_ROOT_TARGET) $(readvar init)"',
+        '        exec switch_root "$(readvar SWITCH_ROOT_TARGET)" "$(readvar init)"',
         "    fi",
         '    rd_fail "Unable to find init."',
         "else",
         f'    einfo "Completed UGRD v{version("ugrd")}."',
-        '    einfo "Switching root to: $(readvar MOUNTS_ROOT_TARGET) $init_target"',
-        '    exec switch_root "$(readvar MOUNTS_ROOT_TARGET)" "$init_target"',
+        '    einfo "Switching root to: $(readvar SWITCH_ROOT_TARGET) $init_target"',
+        '    exec switch_root "$(readvar SWITCH_ROOT_TARGET)" "$init_target"',
         "fi",
     ]
 

src/ugrd/base/base.toml

@@ -20,6 +20,9 @@ autodetect_init = true
 [imports.build_enum]
 "ugrd.base.base" = [ "autodetect_init" ]
 
+[imports.build_tasks]
+"ugrd.base.base" = [ "export_switch_root_target" ]
+
 [imports.init_early]
 "ugrd.base.base" = [ "set_loglevel" ]
 
@@ -32,6 +35,7 @@ autodetect_init = true
 		     "rd_fail", "rd_restart", "_find_init" ]
 
 [custom_parameters]
+switch_root_target = "Path"  # Specifies the location of the new root filesystem
 init_target = "Path"  # Specifies the location of the system init file
 autodetect_init = "bool"  # If set to true, the init_target will be autodetected based on the system's init system
 loglevel = "int"  # Set the kernel log level at /proc/sys/kernel/printk

src/ugrd/fs/livecd.py

@@ -1,24 +1,29 @@
 __author__ = "desultory"
-__version__ = "0.3.0"
+__version__ = "0.5.0"
 
 from zenlib.util import contains
 
 
 @contains("livecd_label", "livecd_label must be set to the label of the livecd.", raise_exception=True)
 def generate_livecd_mount(self):
-    """ Makes the mounts entry for livecd base. """
-    self['mounts'] = {'livecd': {'label': self.livecd_label, 'no_validate': True}}
+    """Makes the mounts entry for livecd base."""
+    self["mounts"] = {"livecd": {"label": self.livecd_label, "no_validate": True}}
+
+
+def prepare_squashfs_mount(self) -> str:
+    """Create the folder for the squashfs mount in /run"""
+    return "edebug $(mkdir -pv /run/squashfs)"
 
 
 @contains("squashfs_image", "squashfs_image must be set to the path of the squashfs image to mount.", raise_exception=True)
-def mount_squashfs(self):
-    """
-    Returns bash lines to mount squashfs image.
-    Creates /run/squashfs directory to mount squashfs image.
-    Creates /run/upperdir and /run/workdir directories for overlayfs.
-    """
-    return ["einfo $(mkdir -pv /run/squashfs)",
-            f"mount -t squashfs -o loop /livecd/{self.squashfs_image} /run/squashfs || rd_fail 'Failed to mount squashfs image: {self.squashfs_image}'",
-            "edebug $(mkdir -pv /run/upperdir)",
-            "edebug $(mkdir -pv /run/workdir)",
-            f"mount -t overlay overlay -o lowerdir=/run/squashfs,upperdir=/run/upperdir,workdir=/run/workdir {self.mounts['root']['destination']} || rd_fail 'Failed to mount overlayfs'"]
+def set_squashfs_mount(self):
+    """Updates the root mount entry to use the squashfs image."""
+    self["mounts"] = {
+        "root": {
+            "type": "squashfs",
+            "options": ["loop"],
+            "path": f"/livecd/{self.squashfs_image}",
+            "destination": "/run/squashfs",
+            "no_validate": True,
+        }
+    }

src/ugrd/fs/livecd.toml

@@ -1,20 +1,16 @@
-autodetect_root = false
-autodetect_root_dm = false
+modules = ["ugrd.fs.overlayfs"]
 
 squashfs_image = 'image.squashfs'
+lowerdir = "/run/squashfs"
+hostonly = false
 
-kmod_init = ['hfsplus', 'nls_utf8', 'squashfs', 'overlay', 'isofs', 'loop']
+kmod_init = ['hfsplus', 'nls_utf8', 'squashfs', 'isofs', 'loop']
 
 [imports.build_pre]
-"ugrd.fs.livecd" = ["generate_livecd_mount"]
+"ugrd.fs.livecd" = ["generate_livecd_mount", "set_squashfs_mount"]
 
-[imports.init_mount]
-"ugrd.fs.livecd" = ["mount_squashfs"]
-
-[masks]
-init_mount = "mount_cmdline_root"  # Don't use the normal mount process
-build_tasks = "export_mount_info"
-functions = "mount_root"
+[imports.init_early]
+"ugrd.fs.livecd" = ["prepare_squashfs_mount"]
 
 [custom_parameters]
 squashfs_image = "Path"  # the path to the squashfs image (at runtime)

src/ugrd/fs/mounts.py

@@ -1,5 +1,5 @@
 __author__ = "desultory"
-__version__ = "5.4.0"
+__version__ = "5.4.2"
 
 from pathlib import Path
 
@@ -216,7 +216,7 @@ def umount_fstab(self) -> list[str]:
     for mount_info in self["mounts"].values():
         if mount_info.get("base_mount"):
             continue
-        if str(mount_info.get("destination")) == "/target_rootfs":
+        if str(mount_info.get("destination")) == str(self["mounts"]["root"]["destination"]):
             continue
 
         mountpoints.append(str(mount_info["destination"]))
@@ -729,10 +729,6 @@ def export_mount_info(self) -> None:
     self["exports"]["MOUNTS_ROOT_SOURCE"] = _get_mount_str(self, self["mounts"]["root"])
     self["exports"]["MOUNTS_ROOT_TYPE"] = self["mounts"]["root"].get("type", "auto")
     self["exports"]["MOUNTS_ROOT_OPTIONS"] = ",".join(self["mounts"]["root"]["options"])
-
-
-def export_root_target(self) -> None:
-    """Exports the root target path to /run/MOUNTS_ROOT_TARGET"""
     self["exports"]["MOUNTS_ROOT_TARGET"] = self["mounts"]["root"]["destination"]
 
 

src/ugrd/fs/mounts.toml

@@ -30,7 +30,7 @@ late_fstab = "/etc/fstab.late"
 		     "autodetect_root", "autodetect_mounts", "autodetect_root_dm", "autodetect_init_mount" ]
 
 [imports.build_tasks]
-"ugrd.fs.mounts" = [ "export_mount_info", "export_root_target" ]
+"ugrd.fs.mounts" = [ "export_mount_info" ]
 
 [imports.build_final]
 "ugrd.fs.mounts" = [ "check_mounts", "generate_fstab" ]

src/ugrd/fs/overlayfs.py

@@ -0,0 +1,22 @@
+from zenlib.util import unset
+
+@unset('lowerdir', "lowerdir is already set, skipping detection.")
+def detect_lowerdir(self):
+    """Detect the lowerdir using the mounts['root']['destination']"""
+    self['lowerdir'] = self.mounts['root']['destination']
+    self.logger.info("Detected lowerdir: %s" % self['lowerdir'])
+
+
+def init_overlayfs(self) -> list[str]:
+    """Returns bash lines to create the upperdir and workdir
+    Uses /run/upperdir and /run/workdir."""
+    return ["edebug $(mkdir -pv /run/upperdir /run/workdir)"]
+
+def mount_overlayfs(self) -> list[str]:
+    """Returns bash lines to mount the overlayfs based on the lowerdir"""
+    return [
+        "einfo $(mount -t overlay overlay -o lowerdir=%s,upperdir=/run/upperdir,workdir=/run/workdir $(readvar SWITCH_ROOT_TARGET))" % self['lowerdir']
+    ]
+
+
+

src/ugrd/fs/overlayfs.toml

@@ -0,0 +1,13 @@
+kmod_init = ["overlay"]
+
+[imports.build_pre]
+"ugrd.fs.overlayfs" = ["detect_lowerdir"]
+
+[imports.init_early]
+"ugrd.fs.overlayfs" = ["init_overlayfs"]
+
+[imports.init_mount]
+"ugrd.fs.overlayfs" = ["mount_overlayfs"]
+
+[custom_parameters]
+lowerdir = "Path"