b49f3f91f9
Extract the `MountGuard` class from all stages that defined it into a new `mnt` utility module.
40 lines
1.2 KiB
Python
40 lines
1.2 KiB
Python
"""Mount utilities
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"""
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import contextlib
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import subprocess
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class MountGuard(contextlib.AbstractContextManager):
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def __init__(self):
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self.mounts = []
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def mount(self, source, target, bind=True, ro=False, mode="0755"):
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options = []
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if bind:
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options += ["bind"]
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if ro:
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options += ["ro"]
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if mode:
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options += [mode]
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args = ["--make-private"]
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if options:
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args += ["-o", ",".join(options)]
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subprocess.run(["mount"] + args + [source, target], check=True)
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self.mounts += [{"source": source, "target": target}]
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def umount(self):
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while self.mounts:
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mount = self.mounts.pop() # FILO: get the last mount
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target = mount["target"]
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# The sync should in theory not be needed but in rare
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# cases `target is busy` error has been spotted.
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# Calling `sync` does not hurt so we keep it for now.
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subprocess.run(["sync", "-f", target], check=True)
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subprocess.run(["umount", target], check=True)
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def __exit__(self, exc_type, exc_val, exc_tb):
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self.umount()
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