Fix up the have_settid test so it works on both plain 2.4 and 2.6 kernels.

I think this will also work on SuSE kernels.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@2062

diff --git a/coregrind/vg_proxylwp.c b/coregrind/vg_proxylwp.c
index 6a6bc5c022cccca32579f21d715b8996faa4e107..23f81c74e06e1d42aeec0e43800cfc6cb3420f19 100644 (file)
--- a/coregrind/vg_proxylwp.c
+++ b/coregrind/vg_proxylwp.c
@@ -892,26 +892,40 @@ static Int have_settid = -1;      /* -1 -> unknown */
 */
 static Int proxy_clone(ProxyLWP *proxy)
 {
-   Int ret;
+   Int ret = -1;
+
+   proxy->lwp = -1;
 
    if (have_settid != 0) {
       ret = VG_(clone)(proxylwp, 
                       LWP_stack(proxy),
                       VKI_CLONE_FS | VKI_CLONE_FILES | VKI_CLONE_VM |
-                      VKI_CLONE_SIGHAND | VKI_CLONE_THREAD /*| 
-                      VKI_CLONE_PARENT_SETTID 
-                      VKI_CLONE_CHILD_CLEARTID | VKI_CLONE_DETACHED*/, 
+                      VKI_CLONE_SIGHAND | VKI_CLONE_THREAD | 
+                      VKI_CLONE_PARENT_SETTID |
+                      VKI_CLONE_CHILD_CLEARTID | VKI_CLONE_DETACHED,
                       proxy, &proxy->lwp, &proxy->lwp);
-      if ( have_settid < 0 && !proxy->lwp ) {
+
+      if ( have_settid == -1 && (ret < 0 || proxy->lwp == 0) ) {
          have_settid = 0;
-         proxy->lwp = ret;
-         VG_(do_signal_routing) = True; /* XXX True, it seems kernels
-                                        which have futex also have
-                                        sensible signal handling, but
-                                        it would be nice to test it
-                                        directly. */
+        
+        /* Assume that not having parent_settid also means that we've
+           got 2.4-style signal handling, which means we need to do
+           more work. */
+         VG_(do_signal_routing) = True;
+
+        if (ret > 0) {
+           /* If clone actually succeeded and just ignored the
+              CLONE_PARENT_SETTID flag, then use the LWP it created
+              for us. */
+           proxy->lwp = ret;
+        }
        }
-   } else {
+   }
+
+   if (ret < 0) {
+      vg_assert(have_settid == 0);
+      vg_assert(proxy->lwp == -1);
+
       ret = VG_(clone)(proxylwp, 
                       LWP_stack(proxy),
                       VKI_CLONE_FS | VKI_CLONE_FILES | VKI_CLONE_VM |