[PATCH] Properly cache the result from looking up the nss database config

[Andreas Schwab <schwab at suse dot de>]

The last argument of __nss_database_lookup is supposed to be used as a
cache for the lookup result, but three callers do not properly make use
of it: they store it in a local variable instead of in the static one
that is defined for that purpose.  __nss_database_lookup is expecting to
be called only once for each database; if there is no config for a
database it reparses the default each time which allocates new memory
(though technically it's not a leak since it frees all of it at program
exit).

Andreas.

	[BZ #15048]
	* nscd/aicache.c (addhstaiX): Properly use the cache variable for
	the nss database lookup.
	* nscd/initgrcache.c (addinitgroupsX): Likewise.
	* sysdeps/posix/getaddrinfo.c (gaih_inet): Likewise.

diff --git a/nscd/aicache.c b/nscd/aicache.c
index 23dcf80..17e06e7 100644
--- a/nscd/aicache.c
+++ b/nscd/aicache.c
@@ -85,20 +85,19 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req,
     }
 
   static service_user *hosts_database;
-  service_user *nip = NULL;
+  service_user *nip;
   int no_more;
   int rc6 = 0;
   int rc4 = 0;
   int herrno = 0;
 
-  if (hosts_database != NULL)
-    {
-      nip = hosts_database;
-      no_more = 0;
-    }
-  else
+  if (hosts_database == NULL)
     no_more = __nss_database_lookup ("hosts", NULL,
-				     "dns [!UNAVAIL=return] files", &nip);
+				     "dns [!UNAVAIL=return] files",
+				     &hosts_database);
+  else
+    no_more = 0;
+  nip = hosts_database;
 
   if (__res_maybe_init (&_res, 0) == -1)
 	    no_more = 1;
diff --git a/nscd/initgrcache.c b/nscd/initgrcache.c
index 196407c8..3981099 100644
--- a/nscd/initgrcache.c
+++ b/nscd/initgrcache.c
@@ -80,17 +80,16 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
     }
 
   static service_user *group_database;
-  service_user *nip = NULL;
+  service_user *nip;
   int no_more;
 
-  if (group_database != NULL)
-    {
-      nip = group_database;
-      no_more = 0;
-    }
-  else
+  if (group_database == NULL)
     no_more = __nss_database_lookup ("group", NULL,
-				     "compat [NOTFOUND=return] files", &nip);
+				     "compat [NOTFOUND=return] files",
+				     &group_database);
+  else
+    no_more = 0;
+  nip = group_database;
 
  /* We always use sysconf even if NGROUPS_MAX is defined.  That way, the
      limit can be raised in the kernel configuration without having to
diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index 2309281..3bf87f5 100644
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -557,7 +557,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	  struct gaih_addrtuple **pat = &at;
 	  int no_data = 0;
 	  int no_inet6_data = 0;
-	  service_user *nip = NULL;
+	  service_user *nip;
 	  enum nss_status inet6_status = NSS_STATUS_UNAVAIL;
 	  enum nss_status status = NSS_STATUS_UNAVAIL;
 	  int no_more;
@@ -790,15 +790,13 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	    }
 #endif
 
-	  if (__nss_hosts_database != NULL)
-	    {
-	      no_more = 0;
-	      nip = __nss_hosts_database;
-	    }
-	  else
+	  if (__nss_hosts_database == NULL)
 	    no_more = __nss_database_lookup ("hosts", NULL,
 					     "dns [!UNAVAIL=return] files",
-					     &nip);
+					     &__nss_hosts_database);
+	  else
+	    no_more = 0;
+	  nip = __nss_hosts_database;
 
 	  /* Initialize configurations.  */
 	  if (__builtin_expect (!_res_hconf.initialized, 0))
-- 
1.8.2.1

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."