Merge lp:~cmiller/desktopcouch/get-port-without-fd-race into lp:desktopcouch

[Chad Miller]

Fix a more obscure find_port bug in which reading all entries in a directory and then inspecting each entry fails, because an entry no longer exists.

[Stuart Langridge (sil)]

review: Approve

[John O'Brien (jdobrien)]

review: Approve

=== modified file 'desktopcouch/__init__.py'
--- desktopcouch/__init__.py	2009-11-20 23:36:40 +0000
+++ desktopcouch/__init__.py	2010-02-08 14:37:12 +0000
@@ -70,11 +70,18 @@
 
     # enumerate the process' file descriptors
     fd_dir = os.path.join(proc_dir, 'fd')
+    fd_paths = list()
     try:
-        fd_paths = [os.readlink(os.path.join(fd_dir, fd))
-                    for fd in os.listdir(fd_dir)]
+        for dirent in os.listdir(fd_dir):
+            try:
+                dirent_path = os.path.join(fd_dir, dirent)
+                fd_paths.append(os.readlink(dirent_path))
+            except OSError:
+                log.debug("dirent %r disappeared before we could read it. " %
+                        (dirent_path,))
+                continue
     except OSError:
-        log.error("Unable to find file descriptors in /proc")
+        log.exception("Unable to find file descriptors in /proc")
         raise RuntimeError("Unable to find file descriptors in /proc")
 
     # identify socket fds