WIP use 2 different processes for stability and not block on VT changes

1 files changed, 46 insertions, 0 deletions

diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
index e41b732..1711581 100644
--- a/src/spice-streaming-agent.cpp
+++ b/src/spice-streaming-agent.cpp
@@ -32,6 +32,9 @@
 #include <poll.h>
 #include <syslog.h>
 #include <signal.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 #include <exception>
 #include <stdexcept>
 #include <memory>
@@ -59,6 +62,10 @@ struct SpiceStreamDataMessage
     StreamMsgData msg;
 };
 
+struct ChildStatus {
+    bool launch_again;
+};
+
 static bool streaming_requested = false;
 static bool quit_requested = false;
 static std::set<SpiceVideoCodecType> client_codecs;
@@ -67,6 +74,9 @@ static const char vt_property_name[] = "XFree86_has_VT";
 static const char *stream_port_name = "/dev/virtio-ports/org.spice-space.stream.0";
 static Atom vt_property = None;
 static std::atomic_bool vt_active;
+#ifdef CHILD_SEP
+static volatile ChildStatus *child_status;
+#endif
 
 static bool have_something_to_read(StreamPort &stream_port, bool blocking, int &fd)
 {
@@ -197,6 +207,9 @@ static void read_command(StreamPort &stream_port, bool blocking)
                 update_fd.ack();
                 bool vt_active = ::vt_active.load(std::memory_order_relaxed);
                 if (!vt_active) {
+#ifdef CHILD_SEP
+                    child_status->launch_again = true;
+#endif
                     exit(0);
                 }
                 continue;
@@ -332,6 +345,9 @@ static void cursor_changes(StreamPort *stream_port, Display *display, int event_
             // update vt property, activate screen read if needed
             bool vt_active = get_win_prop_int(display, rootwindow, vt_property) != 0;
             if (!vt_active) {
+#ifdef CHILD_SEP
+                child_status->launch_again = true;
+#endif
                 // this is necessary as to avoid a clean exit that will hangs :(
                 _Exit(0);
             }
@@ -520,6 +536,36 @@ int main(int argc, char* argv[])
         openlog("spice-streaming-agent",
                 isatty(fileno(stderr)) ? (LOG_PERROR|LOG_PID) : LOG_PID, LOG_USER);
 
+#ifdef CHILD_SEP
+        /* shared a bit of memory with the program which are going to do the hard job */
+        child_status = 
+            (ChildStatus *) mmap(NULL, sizeof(ChildStatus), PROT_READ|PROT_WRITE,
+                                 MAP_SHARED|MAP_ANONYMOUS, -1, 0);
+        if (child_status == MAP_FAILED) {
+            syslog(LOG_ERR, "mmap failed\n");
+            return EXIT_FAILURE;
+        }
+
+        for (;;) {
+            child_status->launch_again = false;
+
+            printf("launching new child\n");
+            pid_t child = fork();
+            if (child == -1) {
+                syslog(LOG_ERR, "fork failed\n");
+                return EXIT_FAILURE;
+            }
+            if (!child)
+                break;
+
+            int status;
+            while (waitpid(child, &status, 0) == -1 && errno == EINTR)
+                continue;
+            if (!child_status->launch_again)
+                return WEXITSTATUS(status);
+        }
+#endif
+
         // this should be done after the fork to avoid duplicating
         // resources