109 lines
3.4 KiB
Python
109 lines
3.4 KiB
Python
# Copyright 2022 Oliver Smith
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# SPDX-License-Identifier: GPL-3.0-or-later
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import os
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import pmb.helpers.run
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def ismount(folder):
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"""
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Ismount() implementation that works for mount --bind.
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Workaround for: https://bugs.python.org/issue29707
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"""
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folder = os.path.realpath(os.path.realpath(folder))
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with open("/proc/mounts", "r") as handle:
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for line in handle:
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words = line.split()
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if len(words) >= 2 and words[1] == folder:
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return True
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if words[0] == folder:
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return True
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return False
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def bind(args, source, destination, create_folders=True, umount=False):
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"""
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Mount --bind a folder and create necessary directory structure.
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:param umount: when destination is already a mount point, umount it first.
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"""
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# Check/umount destination
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if ismount(destination):
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if umount:
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umount_all(args, destination)
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else:
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return
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# Check/create folders
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for path in [source, destination]:
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if os.path.exists(path):
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continue
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if create_folders:
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pmb.helpers.run.root(args, ["mkdir", "-p", path])
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else:
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raise RuntimeError("Mount failed, folder does not exist: " +
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path)
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# Actually mount the folder
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pmb.helpers.run.root(args, ["mount", "--bind", source, destination])
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# Verify that it has worked
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if not ismount(destination):
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raise RuntimeError("Mount failed: " + source + " -> " + destination)
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def bind_file(args, source, destination, create_folders=False):
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"""
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Mount a file with the --bind option, and create the destination file,
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if necessary.
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"""
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# Skip existing mountpoint
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if ismount(destination):
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return
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# Create empty file
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if not os.path.exists(destination):
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if create_folders:
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dir = os.path.dirname(destination)
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if not os.path.isdir(dir):
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pmb.helpers.run.root(args, ["mkdir", "-p", dir])
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pmb.helpers.run.root(args, ["touch", destination])
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# Mount
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pmb.helpers.run.root(args, ["mount", "--bind", source,
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destination])
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def umount_all_list(prefix, source="/proc/mounts"):
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"""
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Parses `/proc/mounts` for all folders beginning with a prefix.
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:source: can be changed for testcases
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:returns: a list of folders that need to be umounted
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"""
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ret = []
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prefix = os.path.realpath(prefix)
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with open(source, "r") as handle:
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for line in handle:
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words = line.split()
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if len(words) < 2:
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raise RuntimeError("Failed to parse line in " + source + ": " +
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line)
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mountpoint = words[1]
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if mountpoint.startswith(prefix):
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# Remove "\040(deleted)" suffix (#545)
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deleted_str = r"\040(deleted)"
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if mountpoint.endswith(deleted_str):
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mountpoint = mountpoint[:-len(deleted_str)]
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ret.append(mountpoint)
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ret.sort(reverse=True)
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return ret
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def umount_all(args, folder):
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"""
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Umount all folders that are mounted inside a given folder.
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"""
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for mountpoint in umount_all_list(folder):
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pmb.helpers.run.root(args, ["umount", mountpoint])
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if ismount(mountpoint):
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raise RuntimeError("Failed to umount: " + mountpoint)
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