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, 2 insertions, 1 deletions

diff --git a/nss/Makefile b/nss/Makefile
index d9f6d41..1e298c2 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -27,7 +27,8 @@ headers			:= nss.h
 # This is the trivial part which goes into libc itself.
 routines		= nsswitch getnssent getnssent_r digits_dots \
 			  valid_field valid_list_field rewrite_field \
-			  $(addsuffix -lookup,$(databases))
+			  $(addsuffix -lookup,$(databases)) \
+			  compat-lookup
 
 # These are the databases that go through nss dispatch.
 # Caution: if you add a database here, you must add its real name