CODEWITHSUNDEEP
pythonwiresharkpcaptsharkpcap.net
Mehboob Alam
Mehboob Alam

Reputation: 7

Subprocess throwing error to run a command

I am tring to write a test case where i download a file(PCAP) file, then i save it with name test1.pcap then i want it to be validated via tshark cli tool,

"tshark -r {} -Y http".format(filename)
``

its says ```
OSError(2, 'No such file or directory')

however the file exists when i check it with os.path.exsists(filename)

My code is:

def test_pcap():

.....
   pcap_response = requests.get(pcap_url)
      assert pcap_response.status_code == 200, "Failed to retrieve PCAP file. Status code: 
{pcap_response.status_code}"
    assert len(pcap_response.content) > 0, "PCAP file is empty"
    print(pcap_response)
    print("PCAP file successfully retrieved.,")

   with open(pcap_file_path, 'w') as f:
        f.write(pcap_response.content)

   if pcap_file_path is None:
        raise ValueError("PCAP file path is None")

   if not os.path.exists(pcap_file_path):
     print("PCAP file does not exist")
   
   isValid = validate_pcap(pcap_file_path)
   print("pcap validation result is: ",isValid)
   process_pcap(pcap_file_path)
   assert isValid, "Sanitized PCAP file still contains sensitive information."

    


def validate_pcap(pcap_file):
    if not os.path.exists(pcap_file):
        print("File does not exist.", pcap_file)
        return False
    try:
        print("tshark -r {} -Y http".format(pcap_file))
        result = subprocess.Popen(
            ["sudo", "tshark", "-r {}".format(pcap_file), "-Y", "http"],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            text=True
        )
        r1, r2 = result.communicate
        print("Next step after result and result is: ", result, r1, r2)
        if result.returncode == 0 and result.stdout:
            print("PCAP file validation passed.")
            print("Output:\n", result.stdout)
            return True
        else:
            print("No matching traffic found or tshark error.")
            print("Error:\n", result.stderr)
            return False
    except Exception as e:
        print("Error running tshark:", e)
        return

Upvotes: 0

Views: 32

Answers (1)

AKX
AKX

Reputation: 169338

You're not printing the same command line you're actually executing, to begin with. Then, you shouldn't need sudo to run tshark if you already have a capture file.

I would suggest using shutil.which() to find tshark:

tshark = shutil.which("tshark")
if not tshark:
    raise FileNotFoundError("tshark not found")
cmd = [tshark, "-r", pcap_file, "-Y", "http"]
result = subprocess.Popen(cmd, ...

Upvotes: 1

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