From 97ec4eecd44f04d6c6580846c1efe9acb75bb06b Mon Sep 17 00:00:00 2001 From: Tom Cherry Date: Wed, 2 Oct 2019 10:52:55 -0700 Subject: [PATCH] liblog: don't set transports to nullptr when they close The old code did not free the transports, just unlink their nodes from the linked list, so there was no race condition between close() and other threads writing to the logs. By settings these to nullptr, I introduced a race condition, but setting them to nullptr isn't necessary, so let's simply not do that. Test: liblog-unit-tests Change-Id: Iec0b680addd13b5d30bd91ccef5bdeab6bf797b0 --- liblog/logger_write.cpp | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-) diff --git a/liblog/logger_write.cpp b/liblog/logger_write.cpp index abcead7b6..678e80961 100644 --- a/liblog/logger_write.cpp +++ b/liblog/logger_write.cpp @@ -34,8 +34,18 @@ #define LOG_BUF_SIZE 1024 -android_log_transport_write* android_log_write = nullptr; +#if (FAKE_LOG_DEVICE == 0) +extern struct android_log_transport_write logdLoggerWrite; +extern struct android_log_transport_write pmsgLoggerWrite; + +android_log_transport_write* android_log_write = &logdLoggerWrite; +android_log_transport_write* android_log_persist_write = &pmsgLoggerWrite; +#else +extern android_log_transport_write fakeLoggerWrite; + +android_log_transport_write* android_log_write = &fakeLoggerWrite; android_log_transport_write* android_log_persist_write = nullptr; +#endif static int __write_to_log_init(log_id_t, struct iovec* vec, size_t nr); static int (*write_to_log)(log_id_t, struct iovec* vec, size_t nr) = __write_to_log_init; @@ -132,9 +142,6 @@ void __android_log_close() { android_log_persist_write->close(); } - android_log_write = nullptr; - android_log_persist_write = nullptr; - #if defined(__ANDROID__) /* * Additional risk here somewhat mitigated by immediately unlock flushing @@ -179,26 +186,11 @@ static bool transport_initialize(android_log_transport_write* transport) { /* log_init_lock assumed */ static int __write_to_log_initialize() { -#if (FAKE_LOG_DEVICE == 0) - extern struct android_log_transport_write logdLoggerWrite; - extern struct android_log_transport_write pmsgLoggerWrite; - - android_log_write = &logdLoggerWrite; - android_log_persist_write = &pmsgLoggerWrite; -#else - extern struct android_log_transport_write fakeLoggerWrite; - - android_log_write = &fakeLoggerWrite; -#endif - if (!transport_initialize(android_log_write)) { - android_log_write = nullptr; return -ENODEV; } - if (!transport_initialize(android_log_persist_write)) { - android_log_persist_write = nullptr; - } + transport_initialize(android_log_persist_write); return 1; }