75 lines
2.2 KiB
Python
Executable File
75 lines
2.2 KiB
Python
Executable File
#! /usr/bin/env python
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# 3) System Test
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#
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# Given a list of directories, report any bogus symbolic links contained
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# anywhere in those subtrees. A bogus symbolic link is one that cannot
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# be resolved because it points to a nonexistent or otherwise
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# unresolvable file. Do *not* use an external find executable.
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# Directories may be very very deep. Print a warning immediately if the
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# system you're running on doesn't support symbolic links.
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# This implementation:
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# - takes one optional argument, using the current directory as default
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# - uses chdir to increase performance
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# - sorts the names per directory
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# - prints output lines of the form "path1 -> path2" as it goes
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# - prints error messages about directories it can't list or chdir into
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import os
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import sys
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from stat import *
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def main():
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try:
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# Note: can't test for presence of lstat -- it's always there
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dummy = os.readlink
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except AttributeError:
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print("This system doesn't have symbolic links")
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sys.exit(0)
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if sys.argv[1:]:
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prefix = sys.argv[1]
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else:
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prefix = ''
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if prefix:
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os.chdir(prefix)
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if prefix[-1:] != '/': prefix = prefix + '/'
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reportboguslinks(prefix)
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else:
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reportboguslinks('')
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def reportboguslinks(prefix):
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try:
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names = os.listdir('.')
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except os.error as msg:
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print("%s%s: can't list: %s" % (prefix, '.', msg))
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return
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names.sort()
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for name in names:
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if name == os.curdir or name == os.pardir:
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continue
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try:
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mode = os.lstat(name)[ST_MODE]
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except os.error:
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print("%s%s: can't stat: %s" % (prefix, name, msg))
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continue
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if S_ISLNK(mode):
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try:
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os.stat(name)
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except os.error:
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print("%s%s -> %s" % \
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(prefix, name, os.readlink(name)))
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elif S_ISDIR(mode):
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try:
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os.chdir(name)
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except os.error as msg:
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print("%s%s: can't chdir: %s" % \
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(prefix, name, msg))
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continue
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try:
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reportboguslinks(prefix + name + '/')
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finally:
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os.chdir('..')
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main()
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