Untangle a particularly badly obfuscated bit of code. No logic changes.

* util.c (setbpt): Calculate new arg0 in more readable way.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

diff --git a/util.c b/util.c
index a03ee4e0a02d09f85b30dc44d436a46da75e1ca9..06b12fc4cf68cf0de257e6031c10c4e6a0d387fb 100644 (file)
--- a/util.c
+++ b/util.c
@@ -1494,9 +1494,9 @@ setbpt(struct tcb *tcp)
                return 0;
 #  endif
 
-       case SYS_clone:
+       case SYS_clone: ;
 #  ifdef SYS_clone2
-       case SYS_clone2:
+       case SYS_clone2: ;
 #  endif
                /* ia64 calls directly `clone (CLONE_VFORK | CLONE_VM)'
                   contrary to x86 SYS_vfork above.  Even on x86 we turn the
@@ -1506,12 +1506,12 @@ setbpt(struct tcb *tcp)
                   clear also CLONE_VM but only in the CLONE_VFORK case as
                   otherwise we would break pthread_create.  */
 
-               if ((arg_setup(tcp, &state) < 0
-                   || set_arg0(tcp, &state,
-                                (tcp->u_arg[arg0_index] | CLONE_PTRACE)
-                                & ~(tcp->u_arg[arg0_index] & CLONE_VFORK
-                                    ? CLONE_VFORK | CLONE_VM : 0)) < 0
-                   || arg_finish_change(tcp, &state) < 0))
+               long new_arg0 = (tcp->u_arg[arg0_index] | CLONE_PTRACE);
+               if (new_arg0 & CLONE_VFORK)
+                       new_arg0 &= ~(unsigned long)(CLONE_VFORK | CLONE_VM);
+               if (arg_setup(tcp, &state) < 0
+                || set_arg0(tcp, &state, new_arg0) < 0
+                || arg_finish_change(tcp, &state) < 0)
                        return -1;
                tcp->flags |= TCB_BPTSET;
                tcp->inst[0] = tcp->u_arg[arg0_index];
@@ -1535,7 +1535,8 @@ clearbpt(struct tcb *tcp)
            || restore_arg0(tcp, &state, tcp->inst[0]) < 0
            || restore_arg1(tcp, &state, tcp->inst[1]) < 0
            || arg_finish_change(tcp, &state))
-               if (errno != ESRCH) return -1;
+               if (errno != ESRCH)
+                       return -1;
        tcp->flags &= ~TCB_BPTSET;
        return 0;
 }