JackLinuxFutex: treat maximum TimedWait() as Wait() and retry on EINTR

FUTEX_WAIT may be interrupted by a signal and return EINTR. If a client
process takes a signal while on the futex, the jack client may error out
with no way to recover despite the signal being safe. Instead, retry if
errno is set to EINTR.

common/JackClient.cpp

@@ -31,6 +31,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #include <math.h>
 #include <string>
 #include <algorithm>
+#include <climits>
 
 using namespace std;
 
@@ -636,7 +637,7 @@ inline int JackClient::CallProcessCallback()
 inline bool JackClient::WaitSync()
 {
     // Suspend itself: wait on the input synchro
-    if (GetGraphManager()->SuspendRefNum(GetClientControl(), fSynchroTable, 0x7FFFFFFF) < 0) {
+    if (GetGraphManager()->SuspendRefNum(GetClientControl(), fSynchroTable, LONG_MAX) < 0) {
         jack_error("SuspendRefNum error");
         return false;
     } else {

linux/JackLinuxFutex.cpp

@@ -23,6 +23,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #include "JackConstants.h"
 #include "JackError.h"
 #include "promiscuous.h"
+#include <climits>
 #include <fcntl.h>
 #include <stdio.h>
 #include <sys/mman.h>
@@ -98,13 +99,19 @@ bool JackLinuxFutex::Wait()
         if (__sync_bool_compare_and_swap(&fFutex->futex, 1, 0))
             return true;
 
-        if (::syscall(SYS_futex, fFutex, fFutex->internal ? FUTEX_WAIT_PRIVATE : FUTEX_WAIT, 0, NULL, NULL, 0) != 0 && errno != EWOULDBLOCK)
+        if (::syscall(SYS_futex, fFutex, fFutex->internal ? FUTEX_WAIT_PRIVATE : FUTEX_WAIT, 0, NULL, NULL, 0) == 0)
+            continue;
+
+        if (errno != EAGAIN && errno != EINTR)
             return false;
     }
 }
 
 bool JackLinuxFutex::TimedWait(long usec)
 {
+    if (usec == LONG_MAX)
+        return Wait();
+
     if (!fFutex) {
         jack_error("JackLinuxFutex::TimedWait name = %s already deallocated!!", fName);
         return false;