adb: fix adb client running out of sockets on Windows (351ecd15) · Commits · e / os / android_system_core

adb/adb.cpp

+5 −3

Original line number	Diff line number	Diff line
		@@ -963,9 +963,11 @@ int handle_host_request(const char* service, TransportType type,
		fflush(stdout);
		SendOkay(reply_fd);

		// At least on Windows, if we exit() without shutdown(SD_SEND) or
		// closesocket(), the client's next recv() will error-out with
		// WSAECONNRESET and they'll never read the OKAY.
		// On Windows, if the process exits with open sockets that
		// shutdown(SD_SEND) has not been called on, TCP RST segments will be
		// sent to the peers which will cause their next recv() to error-out
		// with WSAECONNRESET. In the case of this code, that means the client
		// may not read the OKAY sent above.
		adb_shutdown(reply_fd);

		exit(0);

adb/adb_client.cpp

+7 −0

Original line number	Diff line number	Diff line
		@@ -206,6 +206,7 @@ int adb_connect(const std::string& service, std::string* error) {
		return -1;
		}

		ReadOrderlyShutdown(fd);
		adb_close(fd);

		if (sscanf(&version_string[0], "%04x", &version) != 1) {
		@@ -227,6 +228,7 @@ int adb_connect(const std::string& service, std::string* error) {
		version, ADB_SERVER_VERSION);
		fd = _adb_connect("host:kill", error);
		if (fd >= 0) {
		ReadOrderlyShutdown(fd);
		adb_close(fd);
		} else {
		// If we couldn't connect to the server or had some other error,
		@@ -271,6 +273,8 @@ bool adb_command(const std::string& service) {
		return false;
		}

		ReadOrderlyShutdown(fd);
		adb_close(fd);
		return true;
		}

		@@ -286,5 +290,8 @@ bool adb_query(const std::string& service, std::string* result, std::string* err
		adb_close(fd);
		return false;
		}

		ReadOrderlyShutdown(fd);
		adb_close(fd);
		return true;
		}

adb/adb_io.cpp

+40 −0

Original line number	Diff line number	Diff line
		@@ -137,3 +137,43 @@ bool WriteFdFmt(int fd, const char* fmt, ...) {

		return WriteFdExactly(fd, str);
		}

		bool ReadOrderlyShutdown(int fd) {
		char buf[16];

		// Only call this function if you're sure that the peer does
		// orderly/graceful shutdown of the socket, closing the socket so that
		// adb_read() will return 0. If the peer keeps the socket open, adb_read()
		// will never return.
		int result = adb_read(fd, buf, sizeof(buf));
		if (result == -1) {
		// If errno is EAGAIN, that means this function was called on a
		// nonblocking socket and it would have blocked (which would be bad
		// because we'd probably block the main thread where nonblocking IO is
		// done). Don't do that. If you have a nonblocking socket, use the
		// fdevent APIs to get called on FDE_READ, and then call this function
		// if you really need to, but it shouldn't be needed for server sockets.
		CHECK_NE(errno, EAGAIN);

		// Note that on Windows, orderly shutdown sometimes causes
		// recv() == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET. That
		// can be ignored.
		return false;
		} else if (result == 0) {
		// Peer has performed an orderly/graceful shutdown.
		return true;
		} else {
		// Unexpectedly received data. This is essentially a protocol error
		// because you should not call this function unless you expect no more
		// data. We don't repeatedly call adb_read() until we get zero because
		// we don't know how long that would take, but we do know that the
		// caller wants to close the socket soon.
		VLOG(RWX) << "ReadOrderlyShutdown(" << fd << ") unexpectedly read "
		<< dump_hex(buf, result);
		// Shutdown the socket to prevent the caller from reading or writing to
		// it which doesn't make sense if we just read and discarded some data.
		adb_shutdown(fd);
		errno = EINVAL;
		return false;
		}
		}

adb/adb_io.h

+18 −0

Original line number	Diff line number	Diff line
		@@ -41,6 +41,24 @@ bool ReadProtocolString(int fd, std::string* s, std::string* error);
		// If this function fails, the contents of buf are undefined.
		bool ReadFdExactly(int fd, void* buf, size_t len);

		// Given a client socket, wait for orderly/graceful shutdown. Call this:
		//
		// * Before closing a client socket.
		// * Only when no more data is expected to come in.
		// * Only when the server is not waiting for data from the client (because then
		// the client and server will deadlock waiting for each other).
		// * Only when the server is expected to close its socket right now.
		// * Don't call shutdown(SHUT_WR) before calling this because that will shutdown
		// the client socket early, defeating the purpose of calling this.
		//
		// Waiting for orderly/graceful shutdown of the server socket will cause the
		// server socket to close before the client socket. That prevents the client
		// socket from staying in TIME_WAIT which eventually causes subsequent
		// connect()s from the client to fail with WSAEADDRINUSE on Windows.
		// Returns true if it is sure that orderly/graceful shutdown has occurred with
		// no additional data read from the server.
		bool ReadOrderlyShutdown(int fd);

		// Writes exactly len bytes from buf to fd.
		//
		// Returns false if there is an error or if the fd was closed before the write

adb/commandline.cpp

+3 −0

Original line number	Diff line number	Diff line
		@@ -649,6 +649,7 @@ static int adb_download_buffer(const char service, const char fn, const void*
		std::string error;
		adb_status(fd, &error);
		fprintf(stderr,"* failed to write data '%s' *\n", error.c_str());
		adb_close(fd);
		return -1;
		}
		sz -= xfer;
		@@ -664,6 +665,7 @@ static int adb_download_buffer(const char service, const char fn, const void*

		if (!adb_status(fd, &error)) {
		fprintf(stderr,"* error response '%s' *\n", error.c_str());
		adb_close(fd);
		return -1;
		}

		@@ -1468,6 +1470,7 @@ int adb_commandline(int argc, const char **argv) {
		} else {
		// Successfully connected, kill command sent, okay status came back.
		// Server should exit() in a moment, if not already.
		ReadOrderlyShutdown(fd);
		adb_close(fd);
		return 0;
		}