Re: [Valgrind-users] Wrapping function for strcpy

[Julian S. <js...@ac...>]

On 09/23/2014 03:31 AM, Myoungkyu Song wrote:
> I have a question, which maybe was discussed.  I would like to implement a
> wrapper function for standard API such as "strcpy".  However, I failed to
> do.  When I tested a user-defined function like "hello(char *, char *)"
> below, I successfully wrapped it, accessing to arguments and a return
> value.

The problem is here

> char* I_WRAP_SONAME_FNNAME_ZU(NONE,strcpy) ( char *dest, const char *src )

By using "(NONE,strcpy)" you are requesting to wrap the function strcpy in
the main executable (that's what "NONE") means.  But strcpy lives in
libc.so.  Really you need to use VG_Z_LIBC_SONAME (with a suitable
definition for VG_Z_LIBC_SONAME) to make it work.  Unfortunately the
definition of VG_Z_LIBC_SONAME is system-dependent.

You should be able to find all the examples you need in
shared/vg_replace_strmem.c

Note also, using -v is very helpful for debugging wrapping/intercept
problems.  If you need complete details, also try --trace-redir=yes.

J