[socket-nif] Initiation of "current reader" missing for recvfrom

When calling the recvfrom function when there is no data,
we should be made wait (for the specified amount of time).
But this did not work because the "current reader" structure
was not initiated.

OTP-14831

1 files changed, 12 insertions, 5 deletions

diff --git a/erts/emulator/nifs/common/socket_nif.c b/erts/emulator/nifs/common/socket_nif.c
index 45462ff772..f9eb041ad1 100644
--- a/erts/emulator/nifs/common/socket_nif.c
+++ b/erts/emulator/nifs/common/socket_nif.c
@@ -13377,21 +13377,24 @@ BOOLEAN_T recv_check_reader(ErlNifEnv*        env,
         }
 
         if (!compare_pids(env, &descP->currentReader.pid, &caller)) {
+            ERL_NIF_TERM tmp;
+
             /* Not the "current reader", so (maybe) push onto queue */
 
             SSDBG( descP,
                    ("SOCKET", "recv_check_reader -> not (current) reader\r\n") );
 
             if (!reader_search4pid(env, descP, &caller))
-                *checkResult = reader_push(env, descP, caller, ref);
+                tmp = reader_push(env, descP, caller, ref);
             else
-                *checkResult = esock_make_error(env, esock_atom_eagain);
+                tmp = esock_make_error(env, esock_atom_eagain);
             
             SSDBG( descP,
                    ("SOCKET",
-                    "recv_check_reader -> queue (push) result: %T\r\n",
-                    checkResult) );
-            
+                    "recv_check_reader -> queue (push) result: %T\r\n", tmp) );
+
+            *checkResult = tmp;
+
             return FALSE;
 
         }
@@ -13769,6 +13772,7 @@ ERL_NIF_TERM recvfrom_check_result(ErlNifEnv*        env,
                                    unsigned int      fromAddrLen,
                                    ERL_NIF_TERM      recvRef)
 {
+    char*        xres;
     ERL_NIF_TERM data;
 
     SSDBG( descP,
@@ -13818,6 +13822,9 @@ ERL_NIF_TERM recvfrom_check_result(ErlNifEnv*        env,
 
             SSDBG( descP, ("SOCKET", "recvfrom_check_result -> eagain\r\n") );
             
+            if ((xres = recv_init_current_reader(env, descP, recvRef)) != NULL)
+                return esock_make_error_str(env, xres);
+            
             SELECT(env, descP->sock, (ERL_NIF_SELECT_READ),
                    descP, NULL, recvRef);