Pysftp "cd" fails against AIX server with "OverflowError: mode o

ghz 2days ago ⋅ 8 views

Pysftp "cd" fails against AIX server with "OverflowError: mode out of range" error

Having trouble getting the pysftp.connection.cd() working – not sure what I am doing wrong or what the issue is. I can achieve what I need by passing the full remote path into the relevant methods. But if try to change the remote active directory I get error. Relevant code is below:

with ps.Connection('hostname or IP address', username='username', password='secret', cnopts=cnopts) as conn:
    print("Connection successful....")
    print(conn.listdir()) # this works
    print(conn.listdir(remote_location))  # this works
    with conn.cd(remote_location):  # this throws an error
        print(conn.listdir())

The error I get is below here:

File "C:\Users\username\.conda\envs\data_wrangling\lib\site-packages\pysftp\__init__.py", line 508, in cd
    self.cwd(remotepath)
  File "C:\Users\username\.conda\envs\data_wrangling\lib\site-packages\pysftp\__init__.py", line 524, in chdir
    self._sftp.chdir(remotepath)
  File "C:\Users\username\.conda\envs\data_wrangling\lib\site-packages\paramiko\sftp_client.py", line 659, in chdir
    if not stat.S_ISDIR(self.stat(path).st_mode):
OverflowError: mode out of range

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\Users\username\my_code\python\mears_to_er_interface\sftp_chdir_test.py", line 41, in <module>
    with conn.cd("remote_location"):
  File "C:\Users\username\.conda\envs\data_wrangling\lib\contextlib.py", line 112, in __enter__
    return next(self.gen)
  File "C:\Users\username\.conda\envs\data_wrangling\lib\site-packages\pysftp\__init__.py", line 511, in cd
    self.cwd(original_path)
  File "C:\Users\username\.conda\envs\data_wrangling\lib\site-packages\pysftp\__init__.py", line 524, in chdir
    self._sftp.chdir(remotepath)
  File "C:\Users\username\.conda\envs\data_wrangling\lib\site-packages\paramiko\sftp_client.py", line 659, in chdir
    if not stat.S_ISDIR(self.stat(path).st_mode):
OverflowError: mode out of range

The output for conn.stat(remote_location).st_mode is 83448.

Answer

The error you're encountering (OverflowError: mode out of range) is related to the stat.S_ISDIR(self.stat(path).st_mode) check inside the paramiko library when trying to change directories using cd() in pysftp. Specifically, the issue seems to be related to an invalid or misinterpreted directory mode.

The root cause of the issue might be one or more of the following:

  1. Incorrect or invalid remote_location path: It could be that the path you're passing to conn.cd() is not correct, or there might be some non-standard characters in the path. Double-check the exact path format for the remote directory.

  2. File permissions or symbolic links: The remote path might point to a symbolic link, or there may be permission-related issues on the server that cause an incorrect directory mode to be returned.

Steps to troubleshoot and resolve:

  1. Check the directory exists: Before using conn.cd(), confirm that the directory exists and is accessible.

    print(conn.stat(remote_location))  # This will give you information about the remote location, including permissions

  2. Use conn.chdir() directly: Instead of using the with conn.cd(remote_location): context manager, try using conn.chdir(remote_location) directly. This may give you better error handling.

    try:
    conn.chdir(remote_location)
    print(f"Successfully changed directory to {remote_location}")
except Exception as e:
    print(f"Error: {e}")

  3. Check st_mode: You mentioned that conn.stat(remote_location).st_mode gives 83448. You can verify if this value corresponds to a valid directory mode by printing it and using stat.S_ISDIR():

    import stat
file_mode = conn.stat(remote_location).st_mode
print(f"st_mode: {file_mode}, is directory: {stat.S_ISDIR(file_mode)}")

    If stat.S_ISDIR(file_mode) returns False, it means the path is not a valid directory.

  4. Path format: Ensure that the remote path is in the correct format. Some SFTP servers may require absolute paths, while others work fine with relative paths. For example, try using an absolute path like /home/user/remote_location instead of "remote_location".

  5. Check for symbolic links: If the remote location is a symbolic link, stat.S_ISDIR() might behave unexpectedly, especially with certain server configurations. Try resolving symbolic links with conn.realpath(remote_location):

    real_path = conn.realpath(remote_location)
print(f"Real path: {real_path}")

  6. Handle exceptions more gracefully: The error traceback suggests that there's a secondary error in handling. If conn.cd() fails, you might want to handle this with a try-except block to prevent cascading failures.

Example with full error handling:

import pysftp
import stat

remote_location = "/path/to/remote/dir"

with pysftp.Connection('hostname_or_ip', username='username', password='password') as conn:
    try:
        # Check if the remote path is valid
        path_info = conn.stat(remote_location)
        print(f"st_mode: {path_info.st_mode}, is directory: {stat.S_ISDIR(path_info.st_mode)}")

        # If valid directory, change to it
        if stat.S_ISDIR(path_info.st_mode):
            conn.chdir(remote_location)
            print(f"Successfully changed directory to {remote_location}")
        else:
            print(f"{remote_location} is not a directory.")
        
        # List files in the current directory
        print(conn.listdir())
    
    except Exception as e:
        print(f"Error: {e}")

This example will help you isolate the issue by checking the path first and handling any errors gracefully. If stat.S_ISDIR() returns False, the path is not a valid directory.

#py