sys_futex's FUTEX_(CMP_)REQUEUE requests use the futex2 pointer (not

timeout); FUTEX_CMP_REQUEUE also uses the timespec pointer as an integer.

Also, more clearly document the argument usages, and make the per-operation
special cases clearer.

MERGED FROM CVS HEAD

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@3447

diff --git a/coregrind/linux/syscalls.c b/coregrind/linux/syscalls.c
index 172be91ec1740fe79875582448fea2f40236cd67..3d0d9ce9e6c622a2ba9109918ea4d2ba1ac0725a 100644 (file)
--- a/coregrind/linux/syscalls.c
+++ b/coregrind/linux/syscalls.c
@@ -367,7 +367,7 @@ PRE(sys_prctl, MayBlock)
                  int, option, unsigned long, arg2, unsigned long, arg3,
                  unsigned long, arg4, unsigned long, arg5);
    // XXX: totally wrong... we need to look at the 'option' arg, and do
-   // SYS_PRE_MEM_READs/SYS_PRE_MEM_WRITEs as necessary...
+   // PRE_MEM_READs/PRE_MEM_WRITEs as necessary...
 }
 
 PRE(sys_sendfile, MayBlock)
@@ -404,15 +404,43 @@ POST(sys_sendfile64)
 
 PRE(sys_futex, MayBlock)
 {
+   /* 
+      arg    param                              used by ops
+
+      ARG1 - u32 *futex                                all
+      ARG2 - int op
+      ARG3 - int val                           WAIT,WAKE,FD,REQUEUE,CMP_REQUEUE
+      ARG4 - struct timespec *utime            WAIT:time*      REQUEUE,CMP_REQUEUE:val2
+      ARG5 - u32 *uaddr2                       REQUEUE,CMP_REQUEUE
+      ARG6 - int val3                          CMP_REQUEUE
+    */
    PRINT("sys_futex ( %p, %d, %d, %p, %p )", ARG1,ARG2,ARG3,ARG4,ARG5);
    PRE_REG_READ6(long, "futex", 
                  vki_u32 *, futex, int, op, int, val,
                  struct timespec *, utime, vki_u32 *, uaddr2, int, val3);
-   PRE_MEM_READ( "futex(futex)", ARG1, sizeof(int) );
-   if (ARG2 == VKI_FUTEX_WAIT && ARG4 != 0)
-      PRE_MEM_READ( "futex(timeout)", ARG4, sizeof(struct vki_timespec) );
-   if (ARG2 == VKI_FUTEX_REQUEUE)
-      PRE_MEM_READ( "futex(futex2)", ARG4, sizeof(int) );
+
+   PRE_MEM_READ( "futex(futex)", ARG1, sizeof(Int) );
+
+   switch(ARG2) {
+   case VKI_FUTEX_WAIT:
+      if (ARG4 != 0)
+        PRE_MEM_READ( "futex(timeout)", ARG4, sizeof(struct vki_timespec) );
+      break;
+
+   case VKI_FUTEX_REQUEUE:
+   case VKI_FUTEX_CMP_REQUEUE:
+      PRE_MEM_READ( "futex(futex2)", ARG5, sizeof(Int) );
+      break;
+
+   case VKI_FUTEX_WAKE:
+   case VKI_FUTEX_FD:
+      /* no additional pointers */
+      break;
+
+   default:
+      SET_RESULT(-VKI_ENOSYS);   // some futex function we don't understand
+      break;
+   }
 }
 
 POST(sys_futex)