From f8aea31f40ea9d29b5863e671c9d29d506e36cf8 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 19 Dec 2014 13:28:59 +0530
Subject: [PATCH] Make singleinstance() more robust on OS X

It now handles EINTR and also does not hide all errors in opening the
file or calling lockf()

An error is now reported to the user in a nice error dialog before
aborting startup.
---
 src/calibre/gui2/main.py  | 10 ++++++++--
 src/calibre/utils/lock.py | 11 +++++++----
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index 33fadccda1..830d81c358 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -459,8 +459,14 @@ def main(args=sys.argv):
         app, opts, args = init_qt(args)
     except AbortInit:
         return 1
-    from calibre.utils.lock import singleinstance
-    si = singleinstance(singleinstance_name)
+    try:
+        from calibre.utils.lock import singleinstance
+        si = singleinstance(singleinstance_name)
+    except Exception:
+        error_dialog(None, _('Cannot start calibre'), _(
+            'Failed to start calibre, single instance locking failed. Click "Show Details" for more information'),
+                     det_msg=traceback.format_exc(), show=True)
+        return 1
     if si and opts.shutdown_running_calibre:
         return 0
     if si:
diff --git a/src/calibre/utils/lock.py b/src/calibre/utils/lock.py
index 964c721145..336f5bb1b3 100644
--- a/src/calibre/utils/lock.py
+++ b/src/calibre/utils/lock.py
@@ -233,12 +233,15 @@ else:
         @param name: The name to lock.
         @type name: string
         '''
+        from calibre.utils.ipc import eintr_retry_call
         path = singleinstance_path(name)
+        f = open(path, 'w')
         try:
-            f = open(path, 'w')
-            fcntl.lockf(f.fileno(), fcntl.LOCK_EX|fcntl.LOCK_NB)
+            eintr_retry_call(fcntl.lockf, f.fileno(), fcntl.LOCK_EX|fcntl.LOCK_NB)
             atexit.register(_clean_lock_file, f)
             return True
-        except EnvironmentError:
-            pass
+        except IOError as err:
+            if err.errno == errno.EAGAIN:
+                return False
+            raise
         return False