otg msd helpers

8 files changed, 241 insertions, 17 deletions

diff --git a/kvmd/apps/otgmsd/__init__.py b/kvmd/apps/otgmsd/__init__.py
index 3f32e54f..9be8ab38 100644
--- a/kvmd/apps/otgmsd/__init__.py
+++ b/kvmd/apps/otgmsd/__init__.py
@@ -25,19 +25,35 @@ import signal
 import errno
 import argparse
 
+from typing import List
+from typing import Optional
+
 import psutil
+import yaml
+
+from ...validators.kvm import valid_msd_image_name
+
+from .. import init
 
 
 # =====
-def _set_param(gadget: str, param: str, value: str) -> None:
-    param_path = os.path.join(
+def _make_param_path(gadget: str, param: str) -> str:
+    return os.path.join(
         "/sys/kernel/config/usb_gadget",
         gadget,
         "functions/mass_storage.usb0/lun.0",
         param,
     )
+
+
+def _get_param(gadget: str, param: str) -> str:
+    with open(_make_param_path(gadget, param)) as param_file:
+        return param_file.read().strip()
+
+
+def _set_param(gadget: str, param: str, value: str) -> None:
     try:
-        with open(param_path, "w") as param_file:
+        with open(_make_param_path(gadget, param), "w") as param_file:
             param_file.write(value + "\n")
     except OSError as err:
         if err.errno == errno.EBUSY:
@@ -55,29 +71,57 @@ def _reset_msd() -> None:
                 proc.send_signal(signal.SIGUSR1)
                 found = True
             except Exception as err:
-                SystemExit(f"Can't send SIGUSR1 to MSD kernel thread with pid={attrs['pid']}: {err}")
+                raise SystemExit(f"Can't send SIGUSR1 to MSD kernel thread with pid={attrs['pid']}: {err}")
     if not found:
         raise SystemExit("Can't find MSD kernel thread")
 
 
 # =====
-def main() -> None:
-    parser = argparse.ArgumentParser(description="KVMD OTG MSD Helper")
+def main(argv: Optional[List[str]]=None) -> None:
+    (parent_parser, argv, config) = init(
+        add_help=False,
+        argv=argv,
+        load_msd=True,
+    )
+    parser = argparse.ArgumentParser(
+        prog="kvmd-otg-msd",
+        description="KVMD OTG MSD Helper",
+        parents=[parent_parser],
+    )
     parser.add_argument("--reset", action="store_true", help="Send SIGUSR1 to MSD kernel thread")
-    parser.add_argument("--set-cdrom", dest="cdrom", default=None, choices=["0", "1"], help="Set CD-ROM flag")
-    parser.add_argument("--set-ro", dest="ro", default=None, choices=["0", "1"], help="Set read-only flag")
-    parser.add_argument("--set-image", dest="image_path", default=None, help="Change image path (or eject for the empty)")
-    parser.add_argument("--gadget", default="kvmd", help="USB gadget name")
-    options = parser.parse_args()
+    parser.add_argument("--set-cdrom", default=None, choices=["0", "1"], help="Set CD-ROM flag")
+    parser.add_argument("--set-ro", default=None, choices=["0", "1"], help="Set read-only flag")
+    parser.add_argument("--set-image", default=None, type=valid_msd_image_name, help="Change the image")
+    parser.add_argument("--eject", action="store_true", help="Eject the image")
+    options = parser.parse_args(argv[1:])
+
+    if config.kvmd.msd.type != "otg":
+        raise SystemExit(f"Error: KVMD MSD not using 'otg'"
+                         f" (now configured {config.kvmd.msd.type!r})")
 
     if options.reset:
         _reset_msd()
 
-    if options.cdrom is not None:
-        _set_param(options.gadget, "cdrom", options.cdrom)
+    if options.eject:
+        _set_param(config.otg.gadget, "file", "")
+
+    if options.set_cdrom is not None:
+        _set_param(config.otg.gadget, "cdrom", options.set_cdrom)
+
+    if options.set_ro is not None:
+        _set_param(config.otg.gadget, "ro", options.set_ro)
 
-    if options.ro is not None:
-        _set_param(options.gadget, "ro", options.ro)
+    if options.set_image:
+        path = os.path.join(config.kvmd.msd.storage, "images", options.set_image)
+        if not os.path.isfile(path):
+            raise SystemExit(f"Can't find image {path!r}")
+        _set_param(config.otg.gadget, "file", path)
 
-    if options.image_path is not None:
-        _set_param(options.gadget, "file", options.image_path)
+    print(yaml.dump({  # type: ignore
+        name: _get_param(config.otg.gadget, param)
+        for (param, name) in [
+            ("file", "image"),
+            ("cdrom", "cdrom"),
+            ("ro", "ro"),
+        ]
+    }, default_flow_style=False, sort_keys=False), end="")
diff --git a/kvmd/helpers/__init__.py b/kvmd/helpers/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/kvmd/helpers/__init__.py
diff --git a/kvmd/helpers/otgmsd/__init__.py b/kvmd/helpers/otgmsd/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/kvmd/helpers/otgmsd/__init__.py
diff --git a/kvmd/helpers/otgmsd/remount/__init__.py b/kvmd/helpers/otgmsd/remount/__init__.py
new file mode 100644
index 00000000..2eba6add
--- /dev/null
+++ b/kvmd/helpers/otgmsd/remount/__init__.py
@@ -0,0 +1,64 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2018  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import sys
+import subprocess
+
+
+# ====
+_MOUNT_PATH = "/bin/mount"
+_FSTAB_PATH = "/etc/fstab"
+_OPTION = "X-kvmd.otg-msd"
+
+
+# =====
+def _find_mountpoint() -> str:
+    with open(_FSTAB_PATH) as fstab_file:
+        for line in fstab_file.read().split("\n"):
+            line = line.strip()
+            if line and not line.startswith("#"):
+                parts = line.split()
+                if len(parts) == 6:
+                    options = parts[3].split(",")
+                    if _OPTION in options:
+                        return parts[1]
+    raise SystemExit(f"Can't find {_OPTION!r} mountpoint in {_FSTAB_PATH}")
+
+
+def _remount(path: str, ro: bool) -> None:
+    try:
+        subprocess.check_call([
+            _MOUNT_PATH,
+            "--options",
+            f"remount,{'ro' if ro else 'rw'}",
+            path,
+        ])
+    except subprocess.CalledProcessError as err:
+        raise SystemExit(str(err)) from None
+
+
+# =====
+def main() -> None:
+    if len(sys.argv) != 2 or sys.argv[1] not in ["ro", "rw"]:
+        raise SystemExit(f"This program will remount a first volume marked by {_OPTION!r} option in {_FSTAB_PATH}\n\n"
+                         f"Usage: python -m kvmd.helpers.otgmsd.remount [-h|--help|ro|rw]")
+    _remount(_find_mountpoint(), (sys.argv[1] == "ro"))
diff --git a/kvmd/helpers/otgmsd/remount/__main__.py b/kvmd/helpers/otgmsd/remount/__main__.py
new file mode 100644
index 00000000..77f4e294
--- /dev/null
+++ b/kvmd/helpers/otgmsd/remount/__main__.py
@@ -0,0 +1,24 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2018  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+from . import main
+main()
diff --git a/kvmd/helpers/otgmsd/unlock/__init__.py b/kvmd/helpers/otgmsd/unlock/__init__.py
new file mode 100644
index 00000000..9bdf353f
--- /dev/null
+++ b/kvmd/helpers/otgmsd/unlock/__init__.py
@@ -0,0 +1,54 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2018  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import sys
+import signal
+
+import psutil
+
+
+# =====
+_PROCESS_NAME = "file-storage"
+
+
+# =====
+def _unlock() -> None:
+    # https://github.com/torvalds/linux/blob/3039fad/drivers/usb/gadget/function/f_mass_storage.c#L2924
+    found = False
+    for proc in psutil.process_iter():
+        attrs = proc.as_dict(attrs=["name", "exe"])
+        if attrs.get("name") == _PROCESS_NAME and not attrs.get("exe"):
+            try:
+                proc.send_signal(signal.SIGUSR1)
+                found = True
+            except Exception as err:
+                raise SystemExit(f"Can't send SIGUSR1 to MSD kernel thread with pid={attrs['pid']}: {err}")
+    if not found:
+        raise SystemExit(f"Can't find MSD kernel thread {_PROCESS_NAME!r}")
+
+
+# =====
+def main() -> None:
+    if len(sys.argv) != 2 or sys.argv[1] != "unlock":
+        raise SystemExit(f"This program interrupts all IO operations performed by OTG MSD.\n\n"
+                         f"Usage: python -m kvmd.helpers.otgmsd.unlock [-h|--help|unlock]")
+    _unlock()
diff --git a/kvmd/helpers/otgmsd/unlock/__main__.py b/kvmd/helpers/otgmsd/unlock/__main__.py
new file mode 100644
index 00000000..77f4e294
--- /dev/null
+++ b/kvmd/helpers/otgmsd/unlock/__main__.py
@@ -0,0 +1,24 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2018  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+from . import main
+main()
diff --git a/kvmd/plugins/msd/otg.py b/kvmd/plugins/msd/otg.py
index db1c2254..ca57a932 100644
--- a/kvmd/plugins/msd/otg.py
+++ b/kvmd/plugins/msd/otg.py
@@ -27,6 +27,11 @@ from typing import Dict
 from typing import Type
 from typing import AsyncGenerator
 
+from ...yamlconf import Option
+
+from ...validators.os import valid_abs_path_exists
+from ...validators.os import valid_command
+
 from . import MsdOperationError
 from . import BaseMsd
 
@@ -39,6 +44,15 @@ class MsdCliOnlyError(MsdOperationError):
 
 # =====
 class Plugin(BaseMsd):
+    @classmethod
+    def get_plugin_options(cls) -> Dict:
+        sudo = ["/usr/bin/sudo", "--non-interactive"]
+        return {
+            "storage":     Option("/var/lib/kvmd/msd", type=valid_abs_path_exists, unpack_as="storage_path"),
+            "remount_cmd": Option([*sudo, "/usr/bin/kvmd-helper-otgmsd-remount", "{mode}"], type=valid_command),
+            "unlock_cmd":  Option([*sudo, "/usr/bin/kvmd-helper-otgmsd-unlock", "unlock"], type=valid_command),
+        }
+
     def get_state(self) -> Dict:
         return {
             "enabled": False,