Python file permission check

Checking file permissions in linux with python

Solution 2: Make sure the python location is really Give read & execute permissions to all, and write permission to owner: EDIT: are you getting the error from the command line or in your web browser? It can be confusing when you’re just checking permissions that are already on the file — that’s what bitwise and does: shows you which bits are set on both files.

Checking Linux Directory Permissions with Python

To determine if a particular directory is accessible, use os.access .

os.access('/Directory/Apple', os.R_OK) 

To check all of the immediate subdirs of /Directory , try this loop:

def find_my_group_directory(): #UNTESTED root, dirs, _ = next(os.walk('/Directory')) for dir in dirs: if os.access(os.path.join(root, dir), os.R_OK): return os.path.join(root, dir) return None 

It’s easier to ask forgiveness than permission (EAFP). To check if a directory is accessible:

import os def accessible(dir): try: os.listdir(dir) except OSError: return False return True print(accessible('/root')) 

To check if all the subdirs of a directory are permitted or not, apply this function in a for loop.

Checking File Permissions in Linux with Python, os.stat is the right way to get more general info about a file, including permissions per user, group, and others. The st_mode attribute of the object that os.stat returns has the permission bits for the file. To help interpret those bits, you may want to use the stat module. Code sampledef isgroupreadable(filepath):st = os.stat(filepath)return bool(st.st_mode & stat.S_IRGRP)Feedback

Why am I getting a file permission error with Python

the account the webserver is running as doesn’t have privileges to execute the script, or a directory in the path leading to it.

1. Make sure the python location is really /usr/bin/python
2. Give read & execute permissions to all, and write permission to owner: chmod 755 file.py

EDIT: are you getting the error from the command line or in your web browser? The directory could be configured in the web server not to run CGI scripts.

Another thing to check: Does the directory you have the script in have ExecCGI permissions (assuming you are running Apache)?

How can I get the default file permissions in Python?, Sorted by: 5. For the record, I had a similar issue, here is the code I have used: import os from tempfile import NamedTemporaryFile def UmaskNamedTemporaryFile (*args, **kargs): fdesc = NamedTemporaryFile (*args, **kargs) # we need to set umask to get its current value. As noted # by Florian …

How do I check file permissions with stat?

This is actually simpler that it looks. It can be confusing when you’re just checking permissions that are already on the file — that’s what bitwise and does: shows you which bits are set on both files.

If you simply want a boolean out of that, it’s convenient because with Python treats 0 as False, and the rest of the integers as True. We also don’t even need to bother with the stat.S_IMODE function, we can simply use our bitmask. It doesn’t matter that there’s irrelevant information:

 1 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 # 077 permissions & 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 # see bin(stat.S_IROTH) --------------------------------- 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 

By using & , we only care about what’s in both .

That, plus the Truthy nature of integers means the requested function just looks like this:

def can_user_read(file): return bool(file.stat().st_mode & stat.S_IRUSR) 

Chmod — check permissions of directories in python, i want a python program that given a directory, it will return all directories within that directory that have 775 (rwxrwxr-x) permissions thanks! Stack Overflow. About; Products For Teams; Stack Overflow Public questions & answers; Stack Overflow for Teams Where developers & technologists share …

Check permissions of directories in python

Neither answer recurses, though it’s not entirely clear that that’s what the OP wants. Here’s a recursive approach (untested, but you get the idea):

import os import stat import sys MODE = "775" def mode_matches(mode, file): """Return True if 'file' matches 'mode'. 'mode' should be an integer representing an octal mode (eg int("755", 8) -> 493). """ # Extract the permissions bits from the file's (or # directory's) stat info. filemode = stat.S_IMODE(os.stat(file).st_mode) return filemode == mode try: top = sys.argv[1] except IndexError: top = '.' try: mode = int(sys.argv[2], 8) except IndexError: mode = MODE # Convert mode to octal. mode = int(mode, 8) for dirpath, dirnames, filenames in os.walk(top): dirs = [os.path.join(dirpath, x) for x in dirnames] for dirname in dirs: if mode_matches(mode, dirname): print dirname 

Something similar is described in the stdlib documentation for stat.

Take a look at the os module. In particular os.stat to look at the permission bits.

import os for filename in os.listdir(dirname): path=os.path.join(dirname, filename) if os.path.isdir(path): if (os.stat(path).st_mode & 0777) == 0775: print path 

Compact generator based on Brian’s answer:

import os (fpath for fpath in (os.path.join(dirname,fname) for fname in os.listdir(dirname)) if (os.path.isdir(fpath) and (os.stat(fpath).st_mode & 0777) == 0775)) 

Checking Linux Directory Permissions with Python, I have a Python application running on Linux that needs to return a single directory based upon group permissions. For example, the Linux filesystem looks like this: /Directory/Apple /Directory/Beta /Directory/Carotene There is a group in /etc/group for Apple, Beta, and Carotene.

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Python How to Check if File can be Read or Written

Collection of Checks for Readable and Writable Files.

“Education is the most powerful weapon which you can use to change the world.” ― Nelson Mandela

1. Introduction

It can be a bit cumbersome at times to check for read or write permission on a file. The check might succeed but the actual operation could fail. Also, quite a few edge cases need to be covered to get a reasonable answer from such a check. In this article, we cover some issues with regards to checking read and write permission on a file.

2. Check if File can be Read

A file can be read if it exists and has read permission for the user. Attempting to open the file is the simplest way you can find out if a file can be read. You get an IOError exception if the file cannot be read and you can check errno in the exception for details.

• If errno is errno.ENOENT, the file does not exist.
• If errno is errno.EACCES, the user does not have permission to read the file.

try: with open(argv[1]) as f: s = f.read() print 'read', len(s), 'bytes.' except IOError as x: if x.errno == errno.ENOENT: print argv[1], '- does not exist' elif x.errno == errno.EACCES: print argv[1], '- cannot be read' else: print argv[1], '- some other error'

2.1. Using access()

Sometimes, you don’t care about the reason that open() fails. You just want to know if it succeeds. In such cases, os.access() is an option.

print os.access('joe.txt', os.R_OK) # prints False

print os.access('joe.txt', os.R_OK) # prints False

print os.access('joe.txt', os.R_OK) # prints False

1. By the time you check access() and attempt to actually open the file, the situation may have changed. A readable file might be gone or have its permission changed.

3. Checking if file can be written

Check for file-write is a little bit different from checking readability. If the file does not exist, we need to check the parent directory for write permission.

3.1. Attempt to Write File

Sometimes, the easiest way is to just attempt to write the file. And catch the exception if any is raised.

try: with open(argv[1], 'w') as f: # file opened for writing. write to it here print 'ok' pass except IOError as x: print 'error ', x.errno, ',', x.strerror if x.errno == errno.EACCES: print argv[1], 'no perms' elif x.errno == errno.EISDIR: print argv[1], 'is directory'

As above, the disadvantage of this method is the expense of raising and checking an exception.

3.2. Using access() for checking

When using access() to check permissions, you need not actually open the file. You can apply various conditions to verify writability. In the following procedure, we describe how to go about checking whether a particular file is writable.

Check if the path exists. Different conditions need to be checked depending on whether it exists or not.

if os.path.exists(fnm): # path exists if os.path.isfile(fnm): # is it a file or a dir? .

if os.path.exists(fnm): # path exists if os.path.isfile(fnm): # is it a file or a dir? # also works when file is a link and the target is writable return os.access(fnm, os.W_OK) .

if os.path.exists(fnm): # path exists if os.path.isfile(fnm): # is it a file or a dir? # also works when file is a link and the target is writable return os.access(fnm, os.W_OK) else: return False # path is a dir, so cannot write as a file .

Here is the complete program.

import os.path def check_file_writable(fnm): if os.path.exists(fnm): # path exists if os.path.isfile(fnm): # is it a file or a dir? # also works when file is a link and the target is writable return os.access(fnm, os.W_OK) else: return False # path is a dir, so cannot write as a file # target does not exist, check perms on parent dir pdir = os.path.dirname(fnm) if not pdir: pdir = '.' # target is creatable if parent dir is writable return os.access(pdir, os.W_OK) if __name__ == '__main__': from sys import argv print argv[1], '=>', check_file_writable(argv[1])

3.3. Checking Results

Let us now check to see how it works.

First, remove the checked file and check.

rm joe python check.py joe # prints joe => True

touch joe ls -l joe # prints -rw-rw-r-- 1 xxxxxxx xxxxxxx 0 Feb 10 12:01 joe

python check.py joe # prints joe => True

chmod -w joe python check.py joe # prints joe => False

rm joe; chmod -w . python check.py joe # prints joe => False

chmod +w . mkdir joe python check.py joe # prints joe => False

rmdir joe ln -s not-exists joe python check.py joe # prints joe => True

touch not-exists chmod -w not-exists python check.py joe # prints joe => False

Conclusion

In this article, we have presented a review of methods to check for readability and writability of a file. Opening the file is the surest way to check, but has the cost of raising and catching an exception. Using access() will work, but might be subject to race conditions. Use the knowledge presented here to adjust to your needs.

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