Changeset: f3bdb8dcaebf for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=f3bdb8dcaebf
Modified Files:
monetdb5/modules/mal/mal_mapi.c
Branch: Jan2014
Log Message:
Fix potential race conditions, and avoid killing threads.
diffs (96 lines):
diff --git a/monetdb5/modules/mal/mal_mapi.c b/monetdb5/modules/mal/mal_mapi.c
--- a/monetdb5/modules/mal/mal_mapi.c
+++ b/monetdb5/modules/mal/mal_mapi.c
@@ -178,9 +178,13 @@ doChallenge(stream *in, stream *out) {
MSscheduleClient(buf, challenge, bs, fdout);
}
-static MT_Id listener[8];
-static int lastlistener=0;
-static int serveractive=TRUE;
+static volatile ATOMIC_TYPE nlistener = 0; /* nr of listeners */
+static volatile ATOMIC_TYPE serveractive = 0;
+static volatile ATOMIC_TYPE serverexiting = 0; /* listeners should exit */
+#ifdef ATOMIC_LOCK
+/* lock for all three ATOMIC_TYPE variables above */
+static MT_Lock atomicLock MT_LOCK_INITIALIZER("atomicLock");
+#endif
static void
SERVERlistenThread(SOCKET *Sock)
@@ -199,8 +203,7 @@ SERVERlistenThread(SOCKET *Sock)
GDKfree(Sock);
}
- if (lastlistener < 8)
- listener[lastlistener++] = MT_getpid();
+ (void) ATOMIC_INC(nlistener, atomicLock, "SERVERlistenThread");
do {
FD_ZERO(&fds);
@@ -221,7 +224,8 @@ SERVERlistenThread(SOCKET *Sock)
msgsock = usock;
#endif
retval = select((int)msgsock + 1, &fds, NULL, NULL, &tv);
- if (GDKexiting())
+ if (ATOMIC_GET(serverexiting, atomicLock, "SERVERlistenThread")
||
+ GDKexiting())
break;
if (retval == 0) {
/* nothing interesting has happened */
@@ -236,7 +240,7 @@ SERVERlistenThread(SOCKET *Sock)
}
if (sock != INVALID_SOCKET && FD_ISSET(sock, &fds)) {
if ((msgsock = accept(sock, (SOCKPTR)0, (socklen_t
*)0)) == INVALID_SOCKET) {
- if (MT_geterrno() != EINTR || serveractive ==
FALSE) {
+ if (MT_geterrno() != EINTR ||
!ATOMIC_GET(serveractive, atomicLock, "SERVERlistenThread")) {
msg = "accept failed";
goto error;
}
@@ -330,7 +334,9 @@ SERVERlistenThread(SOCKET *Sock)
doChallenge(
socket_rastream(msgsock, "Server read"),
socket_wastream(msgsock, "Server write"));
- } while (!GDKexiting());
+ } while (!ATOMIC_GET(serverexiting, atomicLock, "SERVERlistenThread") &&
+ !GDKexiting());
+ (void) ATOMIC_DEC(nlistener, atomicLock, "SERVERlistenThread");
return;
error:
fprintf(stderr, "!mal_mapi.listen: %s, terminating listener\n", msg);
@@ -599,12 +605,12 @@ SERVERlisten_port(int *ret, int *pid)
str
SERVERstop(int *ret)
{
- int i;
-
-printf("SERVERstop\n");
- for( i=0; i< lastlistener; i++)
- MT_kill_thread(listener[i]);
- lastlistener = 0;
+fprintf(stderr, "SERVERstop\n");
+ ATOMIC_SET(serverexiting, 1, atomicLock, "SERVERstop");
+ /* wait until they all exited, but skip the wait if the whole
+ * system is going down */
+ while (ATOMIC_GET(nlistener, atomicLock, "SERVERstop") > 0 &&
!GDKexiting())
+ MT_sleep_ms(100);
(void) ret; /* fool compiler */
return MAL_SUCCEED;
}
@@ -614,14 +620,14 @@ str
SERVERsuspend(int *res)
{
(void) res;
- serveractive= FALSE;
+ ATOMIC_SET(serveractive, 0, atomicLock, "SERVERsuspend");
return MAL_SUCCEED;
}
str
SERVERresume(int *res)
{
- serveractive= TRUE;
+ ATOMIC_SET(serveractive, 1, atomicLock, "SERVERsuspend");
(void) res;
return MAL_SUCCEED;
}
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