Release screen mutex if thread dies

We did not setup a thread cleanup procedure which resulted in calcurse
freezing if a thread tried to draw on the screen after another thread
was canceled while locking the screen.

Note that this kind of cleanup handlers should be added to other mutexes
as well. This patch just removes the most common case of triggering a
deadlock.

Also note that we cannot move pthread_cleanup_push() and
pthread_cleanup_pop() into the locking/unlocking functions since both
pthread_cleanup_push() and pthread_cleanup_pop() may be implemented as
macros that must be used in pairs within the same lexical scope.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/calcurse.h b/src/calcurse.h
index 7a7f4f2..d7b5093 100644
--- a/src/calcurse.h
+++ b/src/calcurse.h
@@ -456,6 +456,22 @@ enum win {
 #define FLAG_STA (1 << STA)
 #define FLAG_ALL ((1 << NBWINS) - 1)
 
+#define WINS_NBAR_LOCK \
+  pthread_cleanup_push(wins_nbar_cleanup, NULL); \
+  wins_nbar_lock();
+
+#define WINS_NBAR_UNLOCK \
+  wins_nbar_unlock(); \
+  pthread_cleanup_pop(0);
+
+#define WINS_CALENDAR_LOCK \
+  pthread_cleanup_push(wins_calendar_cleanup, NULL); \
+  wins_calendar_lock();
+
+#define WINS_CALENDAR_UNLOCK \
+  wins_calendar_unlock(); \
+  pthread_cleanup_pop(0);
+
 enum ui_mode {
   UI_CURSES,
   UI_CMDLINE,
@@ -977,8 +993,10 @@ void vars_init(void);
 extern struct window win[NBWINS];
 unsigned wins_nbar_lock(void);
 void wins_nbar_unlock(void);
+void wins_nbar_cleanup(void *);
 unsigned wins_calendar_lock(void);
 void wins_calendar_unlock(void);
+void wins_calendar_cleanup(void *);
 int wins_refresh(void);
 int wins_wrefresh(WINDOW *);
 int wins_doupdate(void);