[Tutor] Problem with os.access function. [semantic error, if check does not work]
alan.gauld at freenet.co.uk
Sun Dec 25 17:06:17 CET 2005
Take a look at my draft OS topic(click the url below).
It will point you at several other functions that will be of use...
Author of the learn to program web tutor
----- Original Message -----
From: "Panagiotis Atmatzidis" <p.atmatzidis at gmail.com>
To: "Python Tutor" <Tutor at python.org>
Sent: Saturday, December 24, 2005 1:20 PM
Subject: [Tutor] Problem with os.access function. [semantic error,if check
does not work]
I am writing a function in order to check if a directory exists. If
exists the functions must do nothing, otherwise must check the users
permissions and if it's possible create the dir. Looking at pydoc's
httpd I found the module "os" and the function "access". From the
access(path, mode) -> 1 if granted, 0 otherwise
Use the real uid/gid to test for access to a path. Note that most
operations will use the effective uid/gid, therefore this routine can
be used in a suid/sgid environment to test if the invoking user has the
specified access to the path. The mode argument can be F_OK to test
existence, or the inclusive-OR of R_OK, W_OK, and X_OK.
This is my function:
path = "/some/dir/" # check the existance of the
mode = 755
check_path = os.access(path, mode)
if check_path == 'False':
print "Directory /some/dir does not exist."
print "Trying to create the directory."
uid = os.geteuid()
print "the uid is ", uid
if uid == '0':
print "The directory has been created."
except OSError, e:
print >>sys.stderr, "The mkdir command failed:
%d (%s)" % (e.errno, e.strerror)
if check_path == '1':
print "The directory /some/dir has been created."
print "Please create the directory /some/dir manually and
then re-run vuhalndler."
print "The directory already exists."
Now the problem lies at the first check " if check_path == 'False':
". It's a semantic error, the program does not really check the dir,
it just takes for granted that the dir exists. I tried with 1 before
putting "False" there.. but it did not work so I took the print result
of check_path and substitute 1 with False. But still nothing :-(
Why does not make the check? I thought that the functions
functionality was clear.. probably is not.
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