commit 10bfb20dad09a433f27dd078b7099444dfa59281
author Mark Salyzyn <salyzyn@google.com> Tue Mar 08 16:18:26 2016 -0800
committer Mark Salyzyn <salyzyn@google.com> Wed Feb 08 13:37:44 2017 -0800
tree 0939db184ee66125fc810d82bd7841b1a05c5396
parent 55da9a19c0795cabfb995a6a036cd1b26074d82a

liblog: add android_log_logger_list management

Add list of android_log_logger_list entities as a way of
accessing the list of transport contexts from within
one of the transports.  This will enable us to iterate back
to an internal transport context which may house a last index
or signalling semaphore to propagate a wakeup on a blocking
read.

Test: gTest libcutils-tests, logd-unit-tests, liblog-unit-tests,
      logcat-unit-tests
Bug: 27405083
Change-Id: I0a5e793946c020d97ffe10192369998e4ed92a83

liblog/logger.h

diff --git a/liblog/logger.h b/liblog/logger.h
index d332c03..471a529 100644
--- a/liblog/logger.h
+++ b/liblog/logger.h
@@ -99,6 +99,7 @@
 };
 
 struct android_log_logger_list {
+  struct listnode node;
   struct listnode logger;
   struct listnode transport;
   int mode;
@@ -146,6 +147,41 @@
          (logp) = node_to_item((logp)->node.next,                   \
                              struct android_log_logger, node))
 
+/*
+ *    Global list of log readers.
+ *
+ * Usage case: search out transport contexts for all readers
+ */
+
+LIBLOG_HIDDEN struct listnode __android_log_readers;
+
+#if defined(_WIN32)
+#define logger_list_rdlock()
+#define logger_list_wrlock()
+#define logger_list_unlock()
+#else
+LIBLOG_HIDDEN pthread_rwlock_t __android_log_readers_lock;
+
+#define logger_list_rdlock() pthread_rwlock_rdlock(&__android_log_readers_lock)
+#define logger_list_wrlock() pthread_rwlock_wrlock(&__android_log_readers_lock)
+#define logger_list_unlock() pthread_rwlock_unlock(&__android_log_readers_lock)
+#endif
+
+/* Must be called with logger_list_rdlock() or logger_list_wrlock() held */
+#define logger_list_for_each(logger_list)                              \
+    for ((logger_list) = node_to_item(&__android_log_readers,          \
+                                      struct android_log_logger_list,  \
+                                      node);                           \
+         (logger_list) != node_to_item(&__android_log_readers,         \
+                                       struct android_log_logger_list, \
+                                       node) &&                        \
+         (logger_list) != node_to_item((logger_list)->node.next,       \
+                                       struct android_log_logger_list, \
+                                       node);                          \
+         (logger_list) = node_to_item((logger_list)->node.next,        \
+                                      struct android_log_logger_list,  \
+                                      node))
+
 /* OS specific dribs and drabs */
 
 #if defined(_WIN32)

liblog/logger_read.c

diff --git a/liblog/logger_read.c b/liblog/logger_read.c
index c3cb7ad..7e50a23 100644
--- a/liblog/logger_read.c
+++ b/liblog/logger_read.c
@@ -228,6 +228,13 @@
     LOGGER_LIST_FUNCTION(logger_list, -ENODEV, setPrune, buf, len);
 }
 
+LIBLOG_HIDDEN struct listnode __android_log_readers =
+    { &__android_log_readers, &__android_log_readers };
+#if !defined(_WIN32)
+LIBLOG_HIDDEN pthread_rwlock_t __android_log_readers_lock =
+    PTHREAD_RWLOCK_INITIALIZER;
+#endif
+
 LIBLOG_ABI_PUBLIC struct logger_list *android_logger_list_alloc(
         int mode,
         unsigned int tail,
@@ -246,6 +253,10 @@
     logger_list->tail = tail;
     logger_list->pid = pid;
 
+    logger_list_wrlock();
+    list_add_tail(&__android_log_readers, &logger_list->node);
+    logger_list_unlock();
+
     return (struct logger_list *)logger_list;
 }
 
@@ -267,6 +278,10 @@
     logger_list->start = start;
     logger_list->pid = pid;
 
+    logger_list_wrlock();
+    list_add_tail(&__android_log_readers, &logger_list->node);
+    logger_list_unlock();
+
     return (struct logger_list *)logger_list;
 }
 
@@ -502,6 +517,10 @@
         return;
     }
 
+    logger_list_wrlock();
+    list_remove(&logger_list_internal->node);
+    logger_list_unlock();
+
     while (!list_empty(&logger_list_internal->transport)) {
         struct listnode *node = list_head(&logger_list_internal->transport);
         struct android_log_transport_context *transp =