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Andrés Muñoz
Asked: 2020-01-12 00:31:03 +0800 CST 2020-01-12 00:31:03 +0800 CST

How to use mknod from python?

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I'm trying to run this script, I got it from here ( http://www.tutorialspoint.com/python/os_mknod.htm ) I use OS: OSX EL Capitan v.10.11.2, Python: 2.7.10:

# !/usr/bin/python

import os
import stat

filename = '/tmp/tmpfile'
mode = 0600|stat.S_IRUSR

# filesystem node specified with different modes
os.mknod(filename, mode)

running it in the terminal without sudo (python testOs.py) returns me:

Traceback (most recent call last):
  File "testOs.py", line 10, in <module>
    os.mknod(filename, mode)
OSError: [Errno 1] Operation not permitted

and running it with sudo (sudo python testOs.py):

Traceback (most recent call last):
  File "testOs.py", line 10, in <module>
    os.mknod(filename, mode)
OSError: [Errno 22] Invalid argument

What am I doing wrong ? What are the correct arguments or where is the error ?

python

1 Answers

  1. Best Answer

    To me, works perfectly. The script is fine.
    You'll have to look for the error outside of the script.

    I have tried to reproduce your error, but I have not succeeded.

    Removing permissions to /tmp:

    test@pc:~/mknod$ sudo chmod a-wxr /tmp
test@pc:~/mknod$ python mk.py
Traceback (most recent call last):
  File "mk.py", line 9, in <module>
    os.mknod(filename, mode)
OSError: [Errno 13] Permission denied
test@pc:~/mknod$ sudo chmod a+wxr /tmp

    Creating the file before:

    test@pc:~/mknod$ touch /tmp/tmpfile 
test@pc:~/mknod$ python mk.py 
Traceback (most recent call last):
  File "mk.py", line 9, in <module>
    os.mknod(filename, mode)
OSError: [Errno 17] File exists

    Please update your question with:

    • The operating system you use
    • The result ofpython --version
    • The result ofls -l / | grep tmp
    • The result ls -l /tmp | grep tmpfilebefore and after executing the script.

    I have tried with Ubuntu 15.10 and Python 2.7.10

    Updated after edit :
    Sure enough, the problem is outside of the script. Apparently this has to do with System Integrity Protection .
    In this answer in English they explain how to deactivate it; But I'm not so sure that's a good idea.
    I don't have OSX ElCapitan and I can't help you anymore.

    Strange use of stat.S_IRUSR
    S_IRUSR means that the user has read permission.
    It's weird that you OR 0600S_IRUSR because 0600it already includes that permission.

    You can check it with this code:

    #!/usr/bin/python
import os
import stat

mode = 0600
print(mode)
mode = 0600|stat.S_IRUSR
print(mode)

    Which in my case gives as output:

    384
    384

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