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I'm using os.walk with followlinks=True, but I hit a place where a symbolic link refers to it's own directory, causing an infinite loop. The culprit in this case is /usr/bin/X11 which list listed as follow :
lrwxrwxrwx 1 root root 1 Apr 24 2015 X11 -> .
Is there any way to avoid following links to either . or .. which I would assume, would cause similar problems? I think I could check this with os.readlink then compare against the current path. Is there any other solution for this?
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Use os. walk() to recursively traverse a directory For each subdirectory in the directory tree, os.
Python's built-in os. walk() is significantly slower than it needs to be, because – in addition to calling os. listdir() on each directory – it executes the stat() system call or GetFileAttributes() on each file to determine whether the entry is a directory or not.
OS. walk() generate the file names in a directory tree by walking the tree either top-down or bottom-up. For each directory in the tree rooted at directory top (including top itself), it yields a 3-tuple (dirpath, dirnames, filenames).
setrecursionlimit(limit) does is: Set the maximum depth of the Python interpreter stack to limit. This limit prevents infinite recursion from causing an overflow of the C stack and crashing Python.
There is no way to avoid storing a set of all the directories visited, if you want to avoid recursion. You do not need to use readlink, however, you can just store inodes. This avoids the problem of path canonicalization altogether.
import os
dirs = set()
for dirpath, dirnames, filenames in os.walk('.', followlinks=True):
st = os.stat(dirpath)
scandirs = []
for dirname in dirnames:
st = os.stat(os.path.join(dirpath, dirname))
dirkey = st.st_dev, st.st_ino
if dirkey not in dirs:
dirs.add(dirkey)
scandirs.append(dirname)
dirnames[:] = scandirs
print(dirpath)
To completely avoid the problem of infinite recursion (with links pointing to where ever) you need to store the files and/or directories you already visited.
The people from pynotify module had the same issue and used the described method. The patch is in the link ;)
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