NSS: Replace exported NSS lookup functions with stubs [BZ #21962]

Commit 384ca551743318bd9c9e24a496d6397f2e3f2a49 from 2007 added this to
nss/XXX-lookup.c:

+#ifndef NO_COMPAT
+int
+internal_function attribute_compat_text_section
+DB_COMPAT_FCT (service_user **ni, const char *fct_name, void **fctp)
+{
+  return DB_LOOKUP_FCT (ni, fct_name, NULL, fctp);
+}
+#endif

That is, it adds a pseudo-compat function with an internal_function
attribute.  The function it was supposed to replace did not have the
attribute:

 extern int DB_LOOKUP_FCT (service_user **ni, const char *fct_name,
-			  void **fctp) internal_function;
+			  const char *fct2_name, void **fctp)
+  internal_function;

This changed the calling convention on i386 for the following
functions in the public ABI:

  __nss_passwd_lookup
  __nss_group_lookup
  __nss_hosts_lookup

This commit replaces the functions with always-failing stubs,
with true compat symbols.  Due to a happy accident, the calling
convention of the stub is identical for the internal_function
and non-internal_function case on i386.

In addition, this commit auto-generates the __nss_*_lookup2
function declarations as part of <nsswitch.h>.

1 files changed, 8 insertions, 0 deletions

diff --git a/nss/nsswitch.h b/nss/nsswitch.h
index 7da9013..2b86d63 100644
--- a/nss/nsswitch.h
+++ b/nss/nsswitch.h
@@ -219,4 +219,12 @@ libc_hidden_proto (__nss_hostname_digits_dots)
 #define MAX_NR_ALIASES  48
 #define MAX_NR_ADDRS    48
 
+/* Prototypes for __nss_*_lookup2 functions.  */
+#define DEFINE_DATABASE(arg)				    \
+  int __nss_##arg##_lookup2 (service_user **, const char *, \
+			     const char *, void **);	    \
+  libc_hidden_proto (__nss_##arg##_lookup2)
+#include "databases.def"
+#undef DEFINE_DATABASE
+
 #endif	/* nsswitch.h */