testsuite: fix override of `stat` on 32-bit architectures

When _FILE_OFFSET_BITS is 64, glibc headers turn `stat` calls into
`stat64`, and our `stat` override into a `stat64` function.  However,
because we use dlsym to get the address of libc's `stat`, we end up
calling into the "real" `stat` function, which deals with 32-bit off_t,
and we treat its result as if it were returned from stat64.  On most
architectures this seems to have been harmless, but on 32-bit mips,
st_mode's offset in struct stat and struct stat64 are different, so we
read garbage.

To fix this, explicitly unset _FILE_OFFSET_BITS in path.c, to turn off
the redirect magic in glibc headers, and override both the 32-bit and
64-bit functions so each call ends up wrapping the right libc function.

Fixes #16 (https://github.com/kmod-project/kmod/issues/16)

diff --git a/testsuite/path.c b/testsuite/path.c
index fa5fcebd18a15f79592ab02647c2164764f326b0..964d33eb25a053ce8052047b8189f97849d891e6 100644 (file)
--- a/testsuite/path.c
+++ b/testsuite/path.c
@@ -15,6 +15,10 @@
  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  */
 
+/* We unset _FILE_OFFSET_BITS here so we can override both stat and stat64 on
+ * 32-bit architectures and forward each to the right libc function */
+#undef _FILE_OFFSET_BITS
+
 #include <assert.h>
 #include <dirent.h>
 #include <dlfcn.h>
@@ -183,23 +187,20 @@ TS_EXPORT int prefix ## stat ## suffix (int ver,      \
 WRAP_1ARG(DIR*, NULL, opendir);
 
 WRAP_2ARGS(FILE*, NULL, fopen, const char*);
+WRAP_2ARGS(FILE*, NULL, fopen64, const char*);
 WRAP_2ARGS(int, -1, mkdir, mode_t);
 WRAP_2ARGS(int, -1, access, int);
 WRAP_2ARGS(int, -1, stat, struct stat*);
 WRAP_2ARGS(int, -1, lstat, struct stat*);
-#ifndef _FILE_OFFSET_BITS
 WRAP_2ARGS(int, -1, stat64, struct stat64*);
 WRAP_2ARGS(int, -1, lstat64, struct stat64*);
 WRAP_OPEN(64);
-#endif
 
 WRAP_OPEN();
 
 #ifdef HAVE___XSTAT
 WRAP_VERSTAT(__x,);
 WRAP_VERSTAT(__lx,);
-#ifndef _FILE_OFFSET_BITS
 WRAP_VERSTAT(__x,64);
 WRAP_VERSTAT(__lx,64);
 #endif
-#endif