Use #nnn as default group name if no password entry for user ID which mod_wsgi-express is run as.

Author: GrahamDumpleton

docs/release-notes/version-4.4.18.rst

@@ -9,3 +9,11 @@ Version 4.4.18 of mod_wsgi can be obtained from:
 For details on the availability of Windows binaries see:
 
   https://github.com/GrahamDumpleton/mod_wsgi/tree/master/win32
+
+Bugs Fixed
+----------
+
+1. If ``mod_wsgi-express`` was run under a user ID for which there was no
+password entry in the system password file, it would fail when looking up
+the group name. If this occurs now use ``#nnn`` as the default group name,
+where ``nnn`` is the user ID.

src/server/__init__.py

@@ -51,15 +51,23 @@ def where():
 
 def default_run_user():
     try:
-        return pwd.getpwuid(os.getuid()).pw_name
+        uid = os.getuid()
+        return pwd.getpwuid(uid).pw_name
     except KeyError:
-        return '#%d' % os.getuid()
+        return '#%d' % uid
 
 def default_run_group():
     try:
-        return grp.getgrgid(pwd.getpwuid(os.getuid()).pw_gid).gr_name
+        uid = os.getuid()
+        entry = pwd.getpwuid(uid)
     except KeyError:
-        return '#%d' % pwd.getpwuid(os.getuid()).pw_gid
+        return '#%d' % uid
+
+    try:
+        gid = entry.pw_gid
+        return grp.getgrgid(gid).gr_name
+    except KeyError:
+        return '#%d' % gid
 
 def find_program(names, default=None, paths=[]):
     for name in names: