Re: [Valgrind-users] NULL parameters in system calls

[Tom H. <th...@cy...>]

In message <105...@ma...>
        Stephane Donze <ste...@ex...> wrote:

> is it possible to patch the syscall wrappers so that they accept legal
> NULL values in their parameters ? I tried to find out how to do that,
> but I think I need some help to understant the many levels of
> indirections in the wrapper invocation.

This should do the trick:

--- valgrind-20030428/coregrind/vg_syscalls.c.accept	2003-04-30 08:31:09.000000000 +0100
+++ valgrind-20030428/coregrind/vg_syscalls.c	2003-04-30 08:32:02.000000000 +0100
@@ -2949,12 +2949,14 @@
                {
                Addr addr_p     = ((UInt*)arg2)[1];
                Addr addrlen_p  = ((UInt*)arg2)[2];
-               buf_and_len_pre_check ( tst, addr_p, addrlen_p,
-                                       "socketcall.accept(addr)",
-                                       "socketcall.accept(addrlen_in)" );
-               KERNEL_DO_SYSCALL(tid,res);
-               buf_and_len_post_check ( tst, res, addr_p, addrlen_p,
-                                        "socketcall.accept(addrlen_out)" );
+               if (addr_p)
+                  buf_and_len_pre_check ( tst, addr_p, addrlen_p,
+                                          "socketcall.accept(addr)",
+                                          "socketcall.accept(addrlen_in)" );
+               KERNEL_DO_SYSCALL(tid,res);
+               if (addr_p)
+                  buf_and_len_post_check ( tst, res, addr_p, addrlen_p,
+                                           "socketcall.accept(addrlen_out)" );
                }
                break;
             }

Tom

-- 
Tom Hughes (th...@cy...)
Software Engineer, Cyberscience Corporation
http://www.cyberscience.com/