Fix test-select-descriptor, test-select-registry.

Both test-select- primitives (in uxio.c) now return 0 only if there
are no INTERRUPTs nor PROCESS-STATUS-CHANGEs pending.  A previous
attempt at this was incomplete or wrong (e.g. not spinning on
interrupted calls when interrupts are masked).

diff --git a/src/microcode/uxio.c b/src/microcode/uxio.c
index 35c8db642be7e2f7c82ebaed095788379b23eb7a..625820af7d6790b681e890254ebb5ddc026af0d9 100644 (file)
--- a/src/microcode/uxio.c
+++ b/src/microcode/uxio.c
@@ -607,7 +607,7 @@ OS_test_select_registry (select_registry_t registry, int blockp)
   while (1)
     {
       int nfds = (safe_poll ((SR_ENTRIES (r)), (SR_N_FDS (r)), blockp));
-      if (nfds >= 0)
+      if (nfds > 0)
        return (nfds);
       if (nfds < 0 && errno != EINTR)
        error_system_call (errno, syscall_select);
@@ -615,6 +615,8 @@ OS_test_select_registry (select_registry_t registry, int blockp)
        return (SELECT_PROCESS_STATUS_CHANGE);
       if (pending_interrupts_p ())
        return (SELECT_INTERRUPT);
+      if (nfds == 0) /* and no status-change nor interrupts pending */
+       return (0);
     }
 }
 
@@ -635,8 +637,8 @@ OS_test_select_descriptor (int fd, int blockp, unsigned int mode)
        return (SELECT_PROCESS_STATUS_CHANGE);
       if (pending_interrupts_p ())
        return (SELECT_INTERRUPT);
-      /* nfds == 0, AND no status-change nor interrupts pending */
-      return (0);
+      if (nfds == 0) /* and no status-change nor interrupts pending */
+       return (0);
     }
 }
 
@@ -809,7 +811,7 @@ OS_test_select_registry (select_registry_t registry, int blockp)
                               (SR_RREADERS (r)),
                               (SR_RWRITERS (r)),
                               blockp));
-      if (nfds >= 0)
+      if (nfds > 0)
        return (nfds);
       if (nfds < 0 && errno != EINTR)
        error_system_call (errno, syscall_select);
@@ -817,6 +819,8 @@ OS_test_select_registry (select_registry_t registry, int blockp)
        return (SELECT_PROCESS_STATUS_CHANGE);
       if (pending_interrupts_p ())
        return (SELECT_INTERRUPT);
+      if (nfds == 0) /* and no status-change nor interrupts pending */
+       return (0);
     }
 #else
   error_system_call (ENOSYS, syscall_select);
@@ -852,8 +856,8 @@ OS_test_select_descriptor (int fd, int blockp, unsigned int mode)
        return (SELECT_PROCESS_STATUS_CHANGE);
       if (pending_interrupts_p ())
        return (SELECT_INTERRUPT);
-      /* nfds == 0, AND no status-change nor interrupts pending */
-      return (0);
+      if (nfds == 0) /* and no status-change nor interrupts pending */
+       return (0);
     }
 #else
   error_system_call (ENOSYS, syscall_select);