Be more careful about default temp dir

diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index db750d4a6e16c9b8f0ef8e72802f416664f6c9ac..f95920d5a4a5609c3de8776f2e2a76c7f677c2d7 100644 (file)
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -17,16 +17,26 @@ template = None
 # Function to calculate the directory to use
 
 def gettempdir():
-       global tempdir
-       if tempdir == None:
-               try:
-                       tempdir = os.environ['TMPDIR']
-               except (KeyError, AttributeError):
-                       if os.name == 'posix':
-                               tempdir = '/usr/tmp' # XXX Why not /tmp?
-                       else:
-                               tempdir = os.getcwd() # XXX Is this OK?
-       return tempdir
+    global tempdir
+    attempdirs = ['/usr/tmp', '/tmp', os.getcwd(), os.curdir]
+    if os.environ.has_key('TMPDIR'):
+       attempdirs.insert(0, os.environ['TMPDIR'])
+    testfile = gettempprefix() + '-*-writetest-*-'
+    for dir in attempdirs:
+       try:
+           filename = os.path.join(dir, testfile)
+           fp = open(filename, 'w')
+           fp.write('blat')
+           fp.close()
+           os.unlink(filename)
+           tempdir = dir
+           break
+       except IOError:
+           pass
+    if tempdir is None:
+       msg = "Can't find a usable temporary directory amongst " + `attempdirs`
+       raise IOError, msg
+    return tempdir
 
 
 # Function to calculate a prefix of the filename to use