Try and fix weird socket I/O issue

diff --git a/src/modules/rlm_sigtran/event.c b/src/modules/rlm_sigtran/event.c
index f70827776b592f8d077a6bcf9788080f6927d03c..5d28bab270657af10ab1e739d5f73e1b768ca561 100644 (file)
--- a/src/modules/rlm_sigtran/event.c
+++ b/src/modules/rlm_sigtran/event.c
@@ -265,6 +265,62 @@ static int event_link_down(sigtran_conn_t *conn)
        return 0;
 }
 
+/** Send response
+ *
+ * @note Works for both blocking and non-blocking sockets
+ *
+ * @param[in] ofd to write response notification to.
+ * @param[in] txn we're confirming.
+ */
+static int event_request_respond(struct osmo_fd *ofd, sigtran_transaction_t *txn)
+{
+       uint8_t buff[sizeof(void *))];
+       uint8_t *p = buff, *end = buff + sizeof(buff);
+
+       memcpy(&buff, &txn, sizeof(buff));
+
+       for (p = buff; p < end; p++) {
+               ssize_t slen;
+
+               slen = write(ofd->fd, p, end - p);
+               if (slen > 0) {
+                       p += slen;
+                       continue;
+               }
+
+               if (errno == EAGAIN) {
+                       int     ret;
+                       fd_set  error_set;
+                       fd_set  write_set;
+
+                       DEBUG3("Got EAGAIN (no buffer space left), waiting for pipe to become writable");
+
+                       FD_ZERO(&error_set);
+                       FD_ZERO(&write_set);
+
+                       FD_SET(ofd->fd, &error_set);
+                       FD_SET(ofd->fd, &write_set);
+
+                       /*
+                        *      Don't let signals mess up the select
+                        */
+                       do {
+                               ret = select(ofd->fd + 1, NULL, &write_set, &error_set, NULL);
+                       } while ((ret == -1) && (errno == EINTR));
+
+                       /*
+                        *      If there wasn't an error try again...
+                        */
+                       if ((ret > 0) && !FD_ISSET(ofd->fd, &error_set)) continue;
+               }
+
+               ERROR("Failed writing to pipe (%i): %s", odf->fd, fr_syserror(errno));
+               return -1;
+       }
+
+       return 0;
+}
+
 /** Processes a request for a new pipe from a worker thread
  *
  * @param ofd  for the main ctrl_pipe.
@@ -296,12 +352,15 @@ static int event_request_handle(struct osmo_fd *ofd, unsigned int what)
        if (len != sizeof(ptr)) {
                ERROR("Data from pipe (%i) too short, expected %zu bytes, got %zu bytes",
                      ofd->fd, sizeof(ptr), len);
-
                ptr = NULL;
-               if (write(ofd->fd, &ptr, sizeof(ptr)) < 0) {
-                       ERROR("Failed registering thread: %s", fr_syserror(errno));
+
+               if (event_request_respond(ofd, txn) < 0) {
+               fatal_error:
+                       DEBUG3("Event loop will exit");
+                       do_exit = true;
                        return -1;
                }
+
                return -1;
        }
 
@@ -325,16 +384,14 @@ static int event_request_handle(struct osmo_fd *ofd, unsigned int what)
                } else {
                        txn->response.type = SIGTRAN_RESPONSE_OK;
                }
-               break;
        }
+               break;
 
        case SIGTRAN_REQUEST_THREAD_UNREGISTER:
                DEBUG3("Deregistering req_pipe (%i).  Signalled by worker", ofd->fd);
                txn->response.type = SIGTRAN_RESPONSE_OK;
-               if (write(ofd->fd, &ptr, sizeof(ptr)) < 0) {
-                       ERROR("Failed informing event client of result: %s", fr_syserror(errno));
-                       return -1;
-               }
+
+               if (event_request_respond(ofd, txn) < 0) goto fatal_error;
                talloc_free(ofd);       /* Ordering is important */
                return 0;
 
@@ -383,13 +440,11 @@ static int event_request_handle(struct osmo_fd *ofd, unsigned int what)
 
        default:
                rad_assert(0);
-               return -1;
+               goto fatal_error;
        }
 
-       if (write(ofd->fd, &ptr, sizeof(ptr)) < 0) {
-               ERROR("Failed informing event client of result: %s", fr_syserror(errno));
-               return -1;
-       }
+       if (event_request_respond(ofd, txn) < 0) goto fatal_error;
+
        return 0;
 }