From 631c56a8e46dea41585f3e7b3ef9c52b49faa385 Mon Sep 17 00:00:00 2001 From: wm4 Date: Tue, 16 Jan 2018 12:57:04 +0100 Subject: [PATCH] avformat: make avformat_network_init() explicitly optional It was sort of optional before - if you didn't call it, networking was initialized on demand, and an ugly warning was logged. Also, the doxygen comments threatened that it would be made strictly required one day. Make it explicitly optional. I would prefer to deprecate it fully, but there might still be legitimate reasons to use this. But the average user won't need it. This is needed only for two reasons: to initialize TLS libraries like OpenSSL and GnuTLS, and winsock. OpenSSL and GnuTLS were already silently initialized on demand if the global network init function was not called. They also have various thread-safety acrobatics, which make concurrent initialization within libavformat safe. In addition, the libraries are moving towards making their global init functions safe, which removes all need for central global init. In particular, GnuTLS 3.5.16 and OpenSSL 1.1.0g have been found to have safe init functions. In all cases, they use internal reference counters to avoid that the global uninit functions interfere with concurrent uses of the library by other API users who called global init. winsock should be thread-safe as well, and maintains an internal reference counter as well. Since we still support ancient TLS libraries, which do not have this fixed, and since it's unknown whether winsock and GnuTLS reinitialization is costly in any way, don't deprecate the libavformat functions yet. --- doc/APIchanges | 6 ++++++ libavformat/avformat.h | 19 +++++++++++++------ libavformat/network.c | 9 --------- libavformat/network.h | 1 - libavformat/utils.c | 2 -- libavformat/version.h | 2 +- 6 files changed, 20 insertions(+), 19 deletions(-) diff --git a/doc/APIchanges b/doc/APIchanges index 0184815224..7699365879 100644 --- a/doc/APIchanges +++ b/doc/APIchanges @@ -15,6 +15,12 @@ libavutil: 2017-10-21 API changes, most recent first: +2018-01-xx - xxxxxxx - lavf 58.5.100 - avformat.h + Explicitly make avformat_network_init() and avformat_network_deinit() optional. + If these are not called, network initialization and deinitialization is + automatic, and unlike in older versions, fully supported, unless libavformat + is linked to ancient GnuTLS and OpenSSL. + 2018-01-xx - xxxxxxx - lavf 58.4.100 - avformat.h Deprecate AVStream.recommended_encoder_configuration. It was useful only for FFserver, which has been removed. diff --git a/libavformat/avformat.h b/libavformat/avformat.h index 8556f80372..b0387214c5 100644 --- a/libavformat/avformat.h +++ b/libavformat/avformat.h @@ -1998,17 +1998,24 @@ void av_register_input_format(AVInputFormat *format); void av_register_output_format(AVOutputFormat *format); /** - * Do global initialization of network components. This is optional, - * but recommended, since it avoids the overhead of implicitly - * doing the setup for each session. + * Do global initialization of network libraries. This is optional, + * and not recommended anymore. * - * Calling this function will become mandatory if using network - * protocols at some major version bump. + * This functions only exists to work around thread-safety issues + * with older GnuTLS or OpenSSL libraries. If libavformat is linked + * to newer versions of those libraries, or if you do not use them, + * calling this function is unnecessary. Otherwise, you need to call + * this function before any other threads using them are started. + * + * This function will be deprecated once support for older GnuTLS and + * OpenSSL libraries is removed, and this function has no purpose + * anymore. */ int avformat_network_init(void); /** - * Undo the initialization done by avformat_network_init. + * Undo the initialization done by avformat_network_init. Call it only + * once for each time you called avformat_network_init. */ int avformat_network_deinit(void); diff --git a/libavformat/network.c b/libavformat/network.c index e9eb4b443a..d5c82e9ab9 100644 --- a/libavformat/network.c +++ b/libavformat/network.c @@ -54,20 +54,11 @@ void ff_tls_deinit(void) #endif } -int ff_network_inited_globally; - int ff_network_init(void) { #if HAVE_WINSOCK2_H WSADATA wsaData; -#endif - if (!ff_network_inited_globally) - av_log(NULL, AV_LOG_WARNING, "Using network protocols without global " - "network initialization. Please use " - "avformat_network_init(), this will " - "become mandatory later.\n"); -#if HAVE_WINSOCK2_H if (WSAStartup(MAKEWORD(1,1), &wsaData)) return 0; #endif diff --git a/libavformat/network.h b/libavformat/network.h index 3c0f873279..e3fda4d5e2 100644 --- a/libavformat/network.h +++ b/libavformat/network.h @@ -75,7 +75,6 @@ int ff_neterrno(void); int ff_socket_nonblock(int socket, int enable); -extern int ff_network_inited_globally; int ff_network_init(void); void ff_network_close(void); diff --git a/libavformat/utils.c b/libavformat/utils.c index 0022639573..3d733417e1 100644 --- a/libavformat/utils.c +++ b/libavformat/utils.c @@ -4885,7 +4885,6 @@ int avformat_network_init(void) { #if CONFIG_NETWORK int ret; - ff_network_inited_globally = 1; if ((ret = ff_network_init()) < 0) return ret; if ((ret = ff_tls_init()) < 0) @@ -4899,7 +4898,6 @@ int avformat_network_deinit(void) #if CONFIG_NETWORK ff_network_close(); ff_tls_deinit(); - ff_network_inited_globally = 0; #endif return 0; } diff --git a/libavformat/version.h b/libavformat/version.h index d566e255e5..87758b027c 100644 --- a/libavformat/version.h +++ b/libavformat/version.h @@ -32,7 +32,7 @@ // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium) // Also please add any ticket numbers that you believe might be affected here #define LIBAVFORMAT_VERSION_MAJOR 58 -#define LIBAVFORMAT_VERSION_MINOR 4 +#define LIBAVFORMAT_VERSION_MINOR 5 #define LIBAVFORMAT_VERSION_MICRO 100 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \