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, 0 deletions

diff --git a/nss/Versions b/nss/Versions
index f8ababccc7..50268ed9b5 100644
--- a/nss/Versions
+++ b/nss/Versions
@@ -7,6 +7,8 @@ libc {
   GLIBC_2.2.2 {
     __nss_hostname_digits_dots;
   }
+  GLIBC_2.27 {
+  }
   GLIBC_PRIVATE {
     _nss_files_parse_grent; _nss_files_parse_pwent; _nss_files_parse_spent;
     __nss_disable_nscd; __nss_lookup_function; _nss_files_parse_sgent;