nss: fix nss_database_lookup2's alternate handling [BZ #27416]

__nss_database_lookup2's extra arguments were left unused in the
nsswitch reloading patch set; this broke compat (default config
ignored) and shadow files (secondary name ignored) which relies on
these fallbacks.

This patch adds in the previous behavior by correcting the
initialization of the database list to reflect the fallbacks.  This
means that the nss_database_lookup2 interface no longer needs to be
passed the fallback info, so API and callers were adjusted.

Since all callers needed to be edited anyway, the calls were changed
from __nss_database_lookup2 to the faster __nss_database_get.  This
was an intended optimization which was deferred during the initial
lookup changes to avoid touching so many files.

The test case verifies that compat targets work (passwd) and that the
default configuration works (group).  Tested on x86-64.

1 files changed, 5 insertions, 12 deletions

diff --git a/nss/XXX-lookup.c b/nss/XXX-lookup.c
index 48fc7b92fc..f1c97f7c8e 100644
--- a/nss/XXX-lookup.c
+++ b/nss/XXX-lookup.c
@@ -37,27 +37,20 @@
 #define CONCAT3_1(Pre, Name, Post) CONCAT3_2 (Pre, Name, Post)
 #define CONCAT3_2(Pre, Name, Post) Pre##Name##Post
 
+#define DATABASE_NAME_ID CONCAT2_1 (nss_database_, DATABASE_NAME)
+#define CONCAT2_1(Pre, Name) CONCAT2_2 (Pre, Name)
+#define CONCAT2_2(Pre, Name) Pre##Name
+
 #define DATABASE_NAME_SYMBOL CONCAT3_1 (__nss_, DATABASE_NAME, _database)
 #define DATABASE_NAME_STRING STRINGIFY1 (DATABASE_NAME)
 #define STRINGIFY1(Name) STRINGIFY2 (Name)
 #define STRINGIFY2(Name) #Name
 
-#ifdef ALTERNATE_NAME
-#define ALTERNATE_NAME_STRING STRINGIFY1 (ALTERNATE_NAME)
-#else
-#define ALTERNATE_NAME_STRING NULL
-#endif
-
-#ifndef DEFAULT_CONFIG
-#define DEFAULT_CONFIG NULL
-#endif
-
 int
 DB_LOOKUP_FCT (nss_action_list *ni, const char *fct_name, const char *fct2_name,
 	       void **fctp)
 {
-  if (__nss_database_lookup2 (DATABASE_NAME_STRING, ALTERNATE_NAME_STRING,
-			      DEFAULT_CONFIG, &DATABASE_NAME_SYMBOL) < 0)
+  if (! __nss_database_get (DATABASE_NAME_ID, &DATABASE_NAME_SYMBOL))
     return -1;
 
   *ni = DATABASE_NAME_SYMBOL;