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