From: mquinson <mquinson@48e7efb5-ca39-0410-a469-dd3cf9ba447f>
Date: Thu, 7 Sep 2006 15:42:29 +0000 (+0000)
Subject: Make sure that we won't try to reuse a socket closed by the user, even if we have... 
X-Git-Tag: v3.3~2573
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/e9f059a161cec95eead6f90b6da546e418ead211

Make sure that we won't try to reuse a socket closed by the user, even if we have dumb users closing sockets containing more buffered messages after the one being handled. Instead, we do a CRITICAL() and ignore the buffered message. Not optimal either, but hell, I don't have any better idea


git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@2786 48e7efb5-ca39-0410-a469-dd3cf9ba447f
---

diff --git a/src/gras/Transport/rl_transport.c b/src/gras/Transport/rl_transport.c
index 6c538b76d0..8b7c9d7151 100644
--- a/src/gras/Transport/rl_transport.c
+++ b/src/gras/Transport/rl_transport.c
@@ -12,6 +12,9 @@
 #include "gras/Transport/transport_private.h"
 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(gras_trp);
 
+/* check transport_private.h for an explanation of this variable */
+gras_socket_t _gras_lastly_selected_socket = NULL;
+
 /**
  * gras_trp_select:
  *
@@ -44,10 +47,9 @@ gras_socket_t gras_trp_select(double timeout) {
 
   /* Check whether there is more data to read from the socket we selected last time.
      This can happen with tcp buffered sockets since we try to get as much data as we can for them */
-  static gras_socket_t _lastly_selected_socket = NULL;
-  if (_lastly_selected_socket && _lastly_selected_socket->moredata) {
-     VERB0("Returning _lastly_selected_socket since there is more data on it");
-     return _lastly_selected_socket;
+  if (_gras_lastly_selected_socket && _gras_lastly_selected_socket->moredata) {
+     VERB0("Returning _gras_lastly_selected_socket since there is more data on it");
+     return _gras_lastly_selected_socket;
   }
   
   /* Compute FD_SETSIZE */
@@ -66,7 +68,7 @@ gras_socket_t gras_trp_select(double timeout) {
       now = gras_os_time();
       DEBUG2("wakeup=%f now=%f",wakeup, now);
       if (now == -1 || now >= wakeup) {
-	/* didn't find anything; no need to update _lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
+	/* didn't find anything; no need to update _gras_lastly_selected_socket since its moredata is 0 (or we would have returned it directly) */
 	THROW1(timeout_error,0,
 	       "Timeout (%f) elapsed with selecting for incomming connexions",
 	       timeout);
@@ -189,14 +191,14 @@ gras_socket_t gras_trp_select(double timeout) {
 	 } else { 
 	   /* Got a suited socket ! */
 	   XBT_OUT;
-	   _lastly_selected_socket = sock_iter;
+	   _gras_lastly_selected_socket = sock_iter;
 	   return sock_iter;
 	 }
 
        } else {
 	 /* This is a file socket. Cannot recv() on it, but it must be alive */
 	   XBT_OUT;
-	   _lastly_selected_socket = sock_iter;
+	   _gras_lastly_selected_socket = sock_iter;
 	   return sock_iter;
        }
 
diff --git a/src/gras/Transport/sg_transport.c b/src/gras/Transport/sg_transport.c
index 99171e95b6..e11b1166be 100644
--- a/src/gras/Transport/sg_transport.c
+++ b/src/gras/Transport/sg_transport.c
@@ -14,6 +14,9 @@
 
 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(gras_trp);
 
+/* check transport_private.h for an explanation of this variable; this just need to be defined to NULL in SG */
+gras_socket_t _gras_lastly_selected_socket = NULL;
+
 /**
  * gras_trp_select:
  *
diff --git a/src/gras/Transport/transport.c b/src/gras/Transport/transport.c
index aff786ee31..d763d9373e 100644
--- a/src/gras/Transport/transport.c
+++ b/src/gras/Transport/transport.c
@@ -345,6 +345,12 @@ void gras_socket_close(gras_socket_t sock) {
 
   XBT_IN;
   VERB1("Close %p",sock);
+  if (sock == _gras_lastly_selected_socket) {
+     if (sock->moredata) 
+       CRITICAL0("Closing a socket which had another message buffered after the one being handled now. Go fix your code.");
+     _gras_lastly_selected_socket=NULL;
+  }
+   
   /* FIXME: Issue an event when the socket is closed */
   if (sock) {
     xbt_dynar_foreach(sockets,cursor,sock_iter) {
diff --git a/src/gras/Transport/transport_private.h b/src/gras/Transport/transport_private.h
index 4d33c193de..becb2627aa 100644
--- a/src/gras/Transport/transport_private.h
+++ b/src/gras/Transport/transport_private.h
@@ -26,6 +26,20 @@
 #include "gras/Virtu/virtu_interface.h" /* libdata management */
 
 extern int gras_trp_libdata_id; /* our libdata identifier */
+
+/* The function that select returned the last time we asked. We need this because the TCP read 
+   are greedy and try to get as much data in their buffer as possible (to avoid subsequent syscalls).
+   (measurement sockets are not buffered and thus not concerned).
+  
+   So, we can get more than one message in one shoot. And when this happens, we have to handle 
+   the same socket again afterward without select()ing at all. 
+ 
+   Then, this data is not a static of the TCP driver because we want to zero it when
+   it gets closed by the user. If not, we use an already freed pointer, which is bad.
+ 
+   It gets tricky since gras_socket_close is part of the common API, not only the RL one. */
+extern gras_socket_t _gras_lastly_selected_socket;
+
 /**
  * s_gras_socket:
  *