[Spice-devel] [PATCH 04/22] Use RAII to cleanup stream in case of exception or return
Frediano Ziglio
fziglio at redhat.com
Wed Feb 28 16:55:23 UTC 2018
>
> From: Christophe de Dinechin <dinechin at redhat.com>
>
> Fix a race condition, make sure we only use stream after opening
> Get rid of C-style 'goto done' in do_capture.
> Get rid of global streamfd, pass it around (cleaned up in later patch)
>
> Signed-off-by: Christophe de Dinechin <dinechin at redhat.com>
> ---
> src/spice-streaming-agent.cpp | 93
> +++++++++++++++++++++++++------------------
> 1 file changed, 54 insertions(+), 39 deletions(-)
>
> diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
> index 18f2b1a..7304576 100644
> --- a/src/spice-streaming-agent.cpp
> +++ b/src/spice-streaming-agent.cpp
> @@ -56,14 +56,39 @@ struct SpiceStreamDataMessage
> StreamMsgData msg;
> };
>
> +struct SpiceStreamCursorMessage
> +{
> + StreamDevHeader hdr;
> + StreamMsgCursorSet msg;
> +};
> +
Spurious lines.
> +class Stream
> +{
> +public:
> + Stream(const char *name)
> + {
> + fd = open(name, O_RDWR);
> + if (fd < 0) {
> + throw std::runtime_error("failed to open streaming device");
> + }
> + }
> + ~Stream()
> + {
> + close(fd);
> + }
> + int file_descriptor() { return fd; }
> +
> +private:
> + int fd = -1;
> +};
> +
> static bool streaming_requested = false;
> static bool quit_requested = false;
> static bool log_binary = false;
> static std::set<SpiceVideoCodecType> client_codecs;
> -static int streamfd = -1;
> static std::mutex stream_mtx;
>
> -static int have_something_to_read(int timeout)
> +static int have_something_to_read(int streamfd, int timeout)
> {
> struct pollfd pollfd = {streamfd, POLLIN, 0};
>
> @@ -79,7 +104,7 @@ static int have_something_to_read(int timeout)
> return 0;
> }
>
> -static void handle_stream_start_stop(uint32_t len)
> +static void handle_stream_start_stop(int streamfd, uint32_t len)
> {
> uint8_t msg[256];
>
> @@ -101,7 +126,7 @@ static void handle_stream_start_stop(uint32_t len)
> }
> }
>
> -static void handle_stream_capabilities(uint32_t len)
> +static void handle_stream_capabilities(int streamfd, uint32_t len)
> {
> uint8_t caps[STREAM_MSG_CAPABILITIES_MAX_BYTES];
>
> @@ -126,13 +151,13 @@ static void handle_stream_capabilities(uint32_t len)
> }
> }
>
> -static void handle_stream_error(uint32_t len)
> +static void handle_stream_error(int streamfd, uint32_t len)
> {
> // TODO read message and use it
> throw std::runtime_error("got an error message from server");
> }
>
> -static void read_command_from_device(void)
> +static void read_command_from_device(int streamfd)
> {
> StreamDevHeader hdr;
> int n;
> @@ -150,27 +175,27 @@ static void read_command_from_device(void)
>
> switch (hdr.type) {
> case STREAM_TYPE_CAPABILITIES:
> - return handle_stream_capabilities(hdr.size);
> + return handle_stream_capabilities(streamfd, hdr.size);
> case STREAM_TYPE_NOTIFY_ERROR:
> - return handle_stream_error(hdr.size);
> + return handle_stream_error(streamfd, hdr.size);
> case STREAM_TYPE_START_STOP:
> - return handle_stream_start_stop(hdr.size);
> + return handle_stream_start_stop(streamfd, hdr.size);
> }
> throw std::runtime_error("UNKNOWN msg of type " +
> std::to_string(hdr.type));
> }
>
> -static int read_command(bool blocking)
> +static int read_command(int streamfd, bool blocking)
> {
> int timeout = blocking?-1:0;
> while (!quit_requested) {
> - if (!have_something_to_read(timeout)) {
> + if (!have_something_to_read(streamfd, timeout)) {
> if (!blocking) {
> return 0;
> }
> sleep(1);
> continue;
> }
> - read_command_from_device();
> + read_command_from_device(streamfd);
> break;
> }
>
> @@ -196,7 +221,7 @@ write_all(int fd, const void *buf, const size_t len)
> return written;
> }
>
> -static int spice_stream_send_format(unsigned w, unsigned h, unsigned c)
> +static int spice_stream_send_format(int streamfd, unsigned w, unsigned h,
> unsigned c)
> {
>
> SpiceStreamFormatMessage msg;
> @@ -217,7 +242,7 @@ static int spice_stream_send_format(unsigned w, unsigned
> h, unsigned c)
> return EXIT_SUCCESS;
> }
>
> -static int spice_stream_send_frame(const void *buf, const unsigned size)
> +static int spice_stream_send_frame(int streamfd, const void *buf, const
> unsigned size)
> {
> SpiceStreamDataMessage msg;
> const size_t msgsize = sizeof(msg);
> @@ -294,7 +319,7 @@ static void usage(const char *progname)
> }
>
> static void
> -send_cursor(unsigned width, unsigned height, int hotspot_x, int hotspot_y,
> +send_cursor(int streamfd, unsigned width, unsigned height, int hotspot_x,
> int hotspot_y,
> std::function<void(uint32_t *)> fill_cursor)
> {
> if (width >= STREAM_MSG_CURSOR_SET_MAX_WIDTH || height >=
> STREAM_MSG_CURSOR_SET_MAX_HEIGHT) {
> @@ -328,7 +353,7 @@ send_cursor(unsigned width, unsigned height, int
> hotspot_x, int hotspot_y,
> write_all(streamfd, msg.get(), cursor_size);
> }
>
> -static void cursor_changes(Display *display, int event_base)
> +static void cursor_changes(int streamfd, Display *display, int event_base)
> {
> unsigned long last_serial = 0;
>
> @@ -353,26 +378,20 @@ static void cursor_changes(Display *display, int
> event_base)
> for (unsigned i = 0; i < cursor->width * cursor->height; ++i)
> pixels[i] = cursor->pixels[i];
> };
> - send_cursor(cursor->width, cursor->height, cursor->xhot,
> cursor->yhot, fill_cursor);
> + send_cursor(streamfd,
> + cursor->width, cursor->height, cursor->xhot,
> cursor->yhot, fill_cursor);
> }
> }
>
> static void
> -do_capture(const char *streamport, FILE *f_log)
> +do_capture(int streamfd, const char *streamport, FILE *f_log)
> {
> - streamfd = open(streamport, O_RDWR);
> - if (streamfd < 0) {
> - throw std::runtime_error("failed to open the streaming device (" +
> - std::string(streamport) + "): "
> - + strerror(errno));
> - }
> -
> unsigned int frame_count = 0;
> while (!quit_requested) {
> while (!quit_requested && !streaming_requested) {
> - if (read_command(true) < 0) {
> + if (read_command(streamfd, true) < 0) {
> syslog(LOG_ERR, "FAILED to read command\n");
> - goto done;
> + return;
> }
> }
>
> @@ -415,7 +434,7 @@ do_capture(const char *streamport, FILE *f_log)
>
> syslog(LOG_DEBUG, "wXh %uX%u codec=%u\n", width, height,
> codec);
>
> - if (spice_stream_send_format(width, height, codec) ==
> EXIT_FAILURE) {
> + if (spice_stream_send_format(streamfd, width, height, codec)
> == EXIT_FAILURE) {
> throw std::runtime_error("FAILED to send format
> message");
> }
> }
> @@ -428,23 +447,18 @@ do_capture(const char *streamport, FILE *f_log)
> hexdump(frame.buffer, frame.buffer_size, f_log);
> }
> }
> - if (spice_stream_send_frame(frame.buffer, frame.buffer_size) ==
> EXIT_FAILURE) {
> + if (spice_stream_send_frame(streamfd,
> + frame.buffer, frame.buffer_size) ==
> EXIT_FAILURE) {
> syslog(LOG_ERR, "FAILED to send a frame\n");
> break;
> }
> //usleep(1);
> - if (read_command(false) < 0) {
> + if (read_command(streamfd, false) < 0) {
> syslog(LOG_ERR, "FAILED to read command\n");
> - goto done;
> + return;
> }
> }
> }
> -
> -done:
> - if (streamfd >= 0) {
> - close(streamfd);
> - streamfd = -1;
> - }
> }
>
> #define arg_error(...) syslog(LOG_ERR, ## __VA_ARGS__);
> @@ -540,12 +554,13 @@ int main(int argc, char* argv[])
> Window rootwindow = DefaultRootWindow(display);
> XFixesSelectCursorInput(display, rootwindow,
> XFixesDisplayCursorNotifyMask);
>
> - std::thread cursor_th(cursor_changes, display, event_base);
> + Stream stream(streamport);
> + std::thread cursor_th(cursor_changes, stream.file_descriptor(), display,
> event_base);
> cursor_th.detach();
>
> int ret = EXIT_SUCCESS;
> try {
> - do_capture(streamport, f_log);
> + do_capture(stream.file_descriptor(), streamport, f_log);
> }
> catch (std::runtime_error &err) {
> syslog(LOG_ERR, "%s\n", err.what());
Rebased at
https://cgit.freedesktop.org/~fziglio/spice-streaming-agent/commit/?h=style3&id=dc5c3b3908652aabda87b5e350e845f6cf37e5eb
Otherwise looks good to me.
Frediano
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