[b2r2lib] Add timeout to the callback thread

The callback thread was polling the b2r2 device
without an explicit timeout. The poll() function
could thus block the thread indefinitely,
even though the b2r2 device may have been closed.
With an explicit timeout, control is guaranteed
to return to the callback thread, allowing it to exit.
Further, a pthread_detach() call was added to have
the thread's context cleaned up, once the thread
terminates.

ST-Ericsson ID: 367329, 356025
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: I789cda9c54ce4a1cd827ca8a0137ab2b5a01562e
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/35313
Reviewed-by: Maciej SOCHA <maciej.socha@stericsson.com>
Tested-by: Maciej SOCHA <maciej.socha@stericsson.com>
Reviewed-by: QATOOLS
Reviewed-by: QATEST
Reviewed-by: Per PERSSON <per.xb.persson@stericsson.com>
Reviewed-by: Jimmy RUBIN <jimmy.rubin@stericsson.com>

1 files changed, 16 insertions, 5 deletions

diff --git a/src/blt_b2r2.c b/src/blt_b2r2.c
index 02f3bc1..cb01738 100644
--- a/src/blt_b2r2.c
+++ b/src/blt_b2r2.c
@@ -32,6 +32,7 @@
 #else
 #  define LOGE(format) fprintf(stderr, LOG_TAG format "\n")
 #  define LOGE2(format, ...) fprintf(stderr, LOG_TAG format "\n", __VA_ARGS__)
+#  define LOGI(format) printf(LOG_TAG format "\n")
 #  define LOGI2(format, ...) printf(LOG_TAG format "\n", __VA_ARGS__)
 #endif
 
@@ -122,6 +123,12 @@ static void free_handle(int handle) {
 
 static void *callback_thread_run(void *arg)
 {
+    /*
+     * The resources consumed by this thread will be freed immediately when
+     * this thread is terminated
+     */
+    pthread_detach(pthread_self());
+
     while (1) {
         int result;
         struct pollfd fds;
@@ -130,7 +137,7 @@ static void *callback_thread_run(void *arg)
         fds.fd = (int)arg;
         fds.events = POLLIN;
 
-        result = poll(&fds, 1, -1);
+        result = poll(&fds, 1, 3000);
         switch (result) {
             case 0:
                 /* timeout occurred */
@@ -154,11 +161,15 @@ static void *callback_thread_run(void *arg)
                         void (*callback)(int, uint32_t) = (void*)report.report1;
                         callback(report.request_id, (uint32_t)report.report2);
                     }
+                } else if (fds.revents & POLLNVAL) {
+                    /* fd not open, device must have been closed */
+                    LOGI("Device closed. Callback thread terminated.\n");
+                    pthread_exit(NULL);
                 } else {
-                    /* We assume that this is because the device was closed */
-                     LOGE2("Other event than POLLIN (%s)",
-                        strerror(errno));
-                     pthread_exit(NULL);
+                    LOGE2("Unexpected event. Callback thread will exit. "
+                        "errno=(%s) result=%d revents=0x%x",
+                        strerror(errno), result, fds.revents);
+                    pthread_exit(NULL);
                 }
                 break;
         }