CODEWITHSUNDEEP
pythonsubprocess
ovangle
ovangle

Reputation: 2031

subprocess cp destination file empty

I'm writing a script which writes it's output to a system directory. Rather than run the entire script using root permissions, I'm writing the output to a temporary file and only using elevated privileges when copying the temporary file to the output.

print(tempfile.read())
return_code = suprocess.call(['/usr/bin/sudo', 'cp', tmpfile.name, outfile])
if return_code != 0:
    print('Copy failed')
    sys.exit(1)
return_code = subprocess.call(['/usr/bin/sudo', 'chmod', '664', outfile])
with open(outfile) as f2:
    print(f2.read())

The first debug prints out the expected contents of the generated file, but the second dprint is empty. In addition, inspecting the file in the filesystem says the file is 0 bytes in length and owned by root.

I've tried the following and it doesn't seem to make a difference:

Upvotes: 0

Views: 669

Answers (1)

ovangle
ovangle

Reputation: 2031

Solved the problem. tempfile was still open for writing when cp was called and the write hadn't flushed to disk when the copy was attempted.

Upvotes: 1

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