From ba0fa9d4bea3dedf129bb6b5e404fb4c15b2136f Mon Sep 17 00:00:00 2001 From: Emmanuele Bassi Date: Thu, 14 Jun 2007 12:00:31 +0000 Subject: [PATCH] 2007-06-14 Emmanuele Bassi * clutter/clutter-timeout-pool.c: Make ClutterTimeoutPool more thread-safe, using a static lock. (clutter_timeout_pool_dispatch), (clutter_timeout_pool_remove): Fix a race condition-turned-in-memory corruption bug, triggered by removing a timeout from the pool while still spinning the pool source. --- ChangeLog | 12 ++++++- clutter/clutter-timeout-pool.c | 79 +++++++++++++++++++++++++++++++++++++----- 2 files changed, 82 insertions(+), 9 deletions(-) diff --git a/ChangeLog b/ChangeLog index 60cf720..e5b92df 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,4 +1,14 @@ -2007-06-07 Emmanuele Bassi +2007-06-14 Emmanuele Bassi + + * clutter/clutter-timeout-pool.c: Make ClutterTimeoutPool + more thread-safe, using a static lock. + + (clutter_timeout_pool_dispatch), (clutter_timeout_pool_remove): Fix + a race condition-turned-in-memory corruption bug, triggered by + removing a timeout from the pool while still spinning the pool + source. + +2007-06-14 Emmanuele Bassi * configure.ac: * doc/manual/Makefile.am: Find xmlto and jw in the path and diff --git a/clutter/clutter-timeout-pool.c b/clutter/clutter-timeout-pool.c index d586d98..2793d05 100644 --- a/clutter/clutter-timeout-pool.c +++ b/clutter/clutter-timeout-pool.c @@ -36,10 +36,16 @@ #include "clutter-timeout-pool.h" typedef struct _ClutterTimeout ClutterTimeout; +typedef enum { + CLUTTER_TIMEOUT_NONE = 0, + CLUTTER_TIMEOUT_ACTIVE = 1 << 0, + CLUTTER_TIMEOUT_READY = 1 << 1 +} ClutterTimeoutFlags; struct _ClutterTimeout { guint id; + ClutterTimeoutFlags flags; guint interval; @@ -54,6 +60,7 @@ struct _ClutterTimeoutPool { GSource source; + GStaticMutex mutex; guint next_id; GList *timeouts; @@ -62,6 +69,12 @@ struct _ClutterTimeoutPool guint id; }; +#define LOCK_POOL(pool) g_static_mutex_lock (&pool->mutex); +#define UNLOCK_POOL(pool) g_static_mutex_unlock (&pool->mutex); + +#define TIMEOUT_REMOVED(timeout) ((timeout->flags & CLUTTER_TIMEOUT_ACTIVE) == 0) +#define TIMEOUT_READY(timeout) ((timeout->flags & CLUTTER_TIMEOUT_READY) == 1) + static gboolean clutter_timeout_pool_prepare (GSource *source, gint *next_timeout); static gboolean clutter_timeout_pool_check (GSource *source); @@ -201,6 +214,7 @@ clutter_timeout_new (guint interval) timeout = g_slice_new0 (ClutterTimeout); timeout->interval = interval; + timeout->flags = CLUTTER_TIMEOUT_NONE; g_get_current_time (¤t_time); clutter_timeout_set_expiration (timeout, ¤t_time); @@ -227,7 +241,8 @@ clutter_timeout_pool_prepare (GSource *source, ClutterTimeoutPool *pool = (ClutterTimeoutPool *) source; GList *l = pool->timeouts; - if (l) + /* the pool is ready if the first timeout is ready */ + if (l && l->data) { ClutterTimeout *timeout = l->data; return clutter_timeout_prepare (source, timeout, next_timeout); @@ -244,15 +259,29 @@ clutter_timeout_pool_check (GSource *source) { ClutterTimeoutPool *pool = (ClutterTimeoutPool *) source; GList *l = pool->timeouts; + + LOCK_POOL (pool); for (l = pool->timeouts; l; l = l->next) { ClutterTimeout *timeout = l->data; + /* since the timeouts are sorted by expiration, as soon + * as we get a check returning FALSE we know that the + * following timeouts are not expiring, so we break as + * soon as possible + */ if (clutter_timeout_check (source, timeout)) - pool->ready += 1; + { + timeout->flags |= CLUTTER_TIMEOUT_READY; + pool->ready += 1; + } + else + break; } + UNLOCK_POOL (pool); + return (pool->ready > 0); } @@ -265,22 +294,40 @@ clutter_timeout_pool_dispatch (GSource *source, GList *l = pool->timeouts; gboolean sort_needed = FALSE; + LOCK_POOL (pool); + + /* the main loop might have predicted this, so we repeat the + * check for ready timeouts. + */ if (!pool->ready) - clutter_timeout_pool_check (source); + { + UNLOCK_POOL (pool); + clutter_timeout_pool_check (source); + LOCK_POOL (pool); + } while (l && l->data && (pool->ready-- > 0)) { ClutterTimeout *timeout = l->data; GList *next = l->next; + gboolean needs_removing = FALSE; + + timeout->flags &= ~CLUTTER_TIMEOUT_READY; - if (clutter_timeout_dispatch (source, timeout)) + if (!TIMEOUT_REMOVED (timeout)) { - sort_needed = TRUE; + needs_removing = !clutter_timeout_dispatch (source, timeout); + sort_needed = needs_removing; } else + needs_removing = TRUE; + + if (needs_removing) { - pool->timeouts = g_list_delete_link (pool->timeouts, l); + pool->timeouts = g_list_remove_link (pool->timeouts, l); + clutter_timeout_free (timeout); + g_list_free1 (l); } l = next; @@ -291,6 +338,8 @@ clutter_timeout_pool_dispatch (GSource *source, pool->ready = 0; + UNLOCK_POOL (pool); + return TRUE; } @@ -299,6 +348,8 @@ clutter_timeout_pool_finalize (GSource *source) { ClutterTimeoutPool *pool = (ClutterTimeoutPool *) source; + g_static_mutex_free (&pool->mutex); + g_list_foreach (pool->timeouts, (GFunc) clutter_timeout_free, NULL); g_list_free (pool->timeouts); } @@ -337,6 +388,7 @@ clutter_timeout_pool_new (gint priority) g_source_set_priority (source, priority); pool = (ClutterTimeoutPool *) source; + g_static_mutex_init (&pool->mutex); pool->next_id = 1; pool->id = g_source_attach (source, NULL); g_source_unref (source); @@ -379,7 +431,11 @@ clutter_timeout_pool_add (ClutterTimeoutPool *pool, ClutterTimeout *timeout; guint retval = 0; + LOCK_POOL (pool); + timeout = clutter_timeout_new (interval); + timeout->flags |= CLUTTER_TIMEOUT_ACTIVE; + retval = timeout->id = pool->next_id++; timeout->func = func; @@ -389,6 +445,8 @@ clutter_timeout_pool_add (ClutterTimeoutPool *pool, pool->timeouts = g_list_insert_sorted (pool->timeouts, timeout, clutter_timeout_sort); + UNLOCK_POOL (pool); + return retval; } @@ -409,11 +467,16 @@ clutter_timeout_pool_remove (ClutterTimeoutPool *pool, { GList *l; + LOCK_POOL (pool); + l = g_list_find_custom (pool->timeouts, GUINT_TO_POINTER (id), clutter_timeout_find_by_id); if (l) { - clutter_timeout_free (l->data); - pool->timeouts = g_list_delete_link (pool->timeouts, l); + ClutterTimeout *timeout = l->data; + + timeout->flags &= ~CLUTTER_TIMEOUT_ACTIVE; } + + UNLOCK_POOL (pool); } -- 2.7.4