Use a loopback UDP socket instead of a pipe.

The ESP32 doesn't provide pipe(), to ensure we can wake up select() we have
to use a socket bound to localhost so we can send a dummy packet to ourself.

diff --git a/src/event.c b/src/event.c
index 6385465361f21a530acf831e91be733fcbf8900f..b74b47c4980f5d7ed7175933204257409357559b 100644 (file)
--- a/src/event.c
+++ b/src/event.c
@@ -192,7 +192,7 @@ static void signalio_handler(event_loop_t *loop, void *data, int flags) {
        (void)flags;
        unsigned char signum;
 
-       if(read(loop->pipefd[0], &signum, 1) != 1) {
+       if(recv(loop->pipefd[0], &signum, 1, MSG_DONTWAIT) != 1) {
                return;
        }
 
@@ -208,14 +208,32 @@ static void signalio_handler(event_loop_t *loop, void *data, int flags) {
        }
 }
 
+static struct sockaddr_in loopback = {0};
+
 static void pipe_init(event_loop_t *loop) {
-       int result = pipe(loop->pipefd);
-       assert(result == 0);
+       meshlink_handle_t *mesh = loop->data;
+
+       loop->pipefd[0] = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+       loop->pipefd[1] = loop->pipefd[0];
+
+       if(loop->pipefd[0] == -1) {
+               logger(mesh, MESHLINK_ERROR, "Could not create UDP socket");
+               return;
+       }
+
+       loopback.sin_family = AF_INET;
+       loopback.sin_port = 1024;
+       loopback.sin_addr.s_addr = htonl(0x7F000001);
+
+       int result = bind(loop->pipefd[0], (struct sockaddr *)&loopback, sizeof(loopback));
+
+       if(result == -1) {
+               logger(mesh, MESHLINK_ERROR, "Could not bind UDP socket to localhost");
+       }
 
        if(result == 0) {
 #ifdef O_NONBLOCK
                fcntl(loop->pipefd[0], F_SETFL, O_NONBLOCK);
-               fcntl(loop->pipefd[1], F_SETFL, O_NONBLOCK);
 #endif
                io_add(loop, &loop->signalio, signalio_handler, NULL, loop->pipefd[0], IO_READ);
        }
@@ -225,13 +243,14 @@ static void pipe_exit(event_loop_t *loop) {
        io_del(loop, &loop->signalio);
 
        close(loop->pipefd[0]);
-       close(loop->pipefd[1]);
 
        loop->pipefd[0] = -1;
        loop->pipefd[1] = -1;
 }
 
 void signal_trigger(event_loop_t *loop, signal_t *sig) {
+       meshlink_handle_t *mesh = loop->data;
+
 #ifdef HAVE_STDATOMIC_H
 
        if(atomic_flag_test_and_set(&sig->set)) {
@@ -241,7 +260,7 @@ void signal_trigger(event_loop_t *loop, signal_t *sig) {
 #endif
 
        uint8_t signum = sig->signum;
-       write(loop->pipefd[1], &signum, 1);
+       sendto(loop->pipefd[1], &signum, 1, MSG_DONTWAIT, (struct sockaddr *)&loopback, sizeof(loopback));
        return;
 }