glibc/glibc-nis-splitgroups.diff

2009-04-19  Petr Baudis  <pasky@suse.cz>

	* nis/Makefile (libnss_compat-routines): Add build dependency
	  on nss-nis.
	* nis/nss: New variable SPLIT_GROUPS.
	* nis/libnsl.h: New flag NSS_FLAG_SPLIT_GROUPS.
	* nis/nss-default.c: Likewise.
	* nss_compat/compat-initgroups.c: Do not use initgroups_dyn
	  in case NSS_FLAG_SPLIT_GROUPS is set.

diff --git a/nis/Makefile b/nis/Makefile
index 8083ee8..9814fce 100644
--- nis/Makefile
+++ nis/Makefile
@@ -56,7 +56,8 @@ libnsl-routines = yp_xdr ypclnt ypupdate_xdr \
 		  nis_findserv nis_callback nis_clone_dir nis_clone_obj\
 		  nis_clone_res nss-default
 
-libnss_compat-routines	:= $(addprefix compat-,grp pwd spwd initgroups)
+libnss_compat-routines	:= $(addprefix compat-,grp pwd spwd initgroups) \
+			   nss-nis
 libnss_compat-inhibit-o	= $(filter-out .os,$(object-suffixes))
 
 libnss_nis-routines	:= $(addprefix nis-,$(databases)) nis-initgroups \
diff --git a/nis/libnsl.h b/nis/libnsl.h
index c6ceb32..77c34ef 100644
--- nis/libnsl.h
+++ nis/libnsl.h
@@ -21,6 +21,7 @@
 #define NSS_FLAG_NETID_AUTHORITATIVE	1
 #define NSS_FLAG_SERVICES_AUTHORITATIVE	2
 #define NSS_FLAG_SETENT_BATCH_READ	4
+#define NSS_FLAG_SPLIT_GROUPS		8
 
 
 /* Get current set of default flags.  */
diff --git a/nis/nss b/nis/nss
index aab40ab..4715ab5 100644
--- nis/nss
+++ nis/nss
@@ -1,7 +1,7 @@
 # /etc/default/nss
 # This file can theoretically contain a bunch of customization variables
 # for Name Service Switch in the GNU C library.  For now there are only
-# three variables:
+# four variables:
 #
 # NETID_AUTHORITATIVE
 #   If set to TRUE, the initgroups() function will accept the information
@@ -26,3 +26,11 @@
 #  might result into a network communication with the server to get
 #  the next entry.
 #SETENT_BATCH_READ=TRUE
+#
+# SPLIT_GROUPS
+#   If set to TRUE, the nss_compat module's initgroups() function will
+#   not use the NIS initgroups interface for retrieving group information.
+#   This allows one NIS group to be split into multiple database entries
+#   with same gid, a practice used to overcome entry length limitations.
+#   The downside is a certain performance degradation.
+#SPLIT_GROUPS=TRUE
diff --git a/nis/nss-default.c b/nis/nss-default.c
index 046ddfe..d6141b9 100644
--- nis/nss-default.c
+++ nis/nss-default.c
@@ -48,6 +48,7 @@ static const struct
     { STRNLEN ("NETID_AUTHORITATIVE"), NSS_FLAG_NETID_AUTHORITATIVE },
     { STRNLEN ("SERVICES_AUTHORITATIVE"), NSS_FLAG_SERVICES_AUTHORITATIVE },
-    { STRNLEN ("SETENT_BATCH_READ"), NSS_FLAG_SETENT_BATCH_READ }
+    { STRNLEN ("SETENT_BATCH_READ"), NSS_FLAG_SETENT_BATCH_READ },
+    { STRNLEN ("SPLIT_GROUPS"), NSS_FLAG_SPLIT_GROUPS },
   };
 #define nvars (sizeof (vars) / sizeof (vars[0]))
 
diff --git a/nis/nss_compat/compat-initgroups.c b/nis/nss_compat/compat-initgroups.c
index 76ca95d..14b0aac 100644
--- nis/nss_compat/compat-initgroups.c
+++ nis/nss_compat/compat-initgroups.c
@@ -32,6 +32,9 @@
 #include <bits/libc-lock.h>
 #include <kernel-features.h>
 
+/* Get the declaration of the NSS flags. */
+#include <libnsl.h>
+
 static service_user *ni;
 /* Type of the lookup function.  */
 static enum nss_status (*nss_initgroups_dyn) (const char *, gid_t,
@@ -103,7 +106,10 @@ init_nss_interface (void)
   if (ni == NULL
       && __nss_database_lookup ("group_compat", NULL, "nis", &ni) >= 0)
     {
-      nss_initgroups_dyn = __nss_lookup_function (ni, "initgroups_dyn");
+      if (_nsl_default_nss () & NSS_FLAG_SPLIT_GROUPS)
+ 	nss_initgroups_dyn = NULL;
+      else
+	nss_initgroups_dyn = __nss_lookup_function (ni, "initgroups_dyn");
       nss_getgrnam_r = __nss_lookup_function (ni, "getgrnam_r");
       nss_getgrgid_r = __nss_lookup_function (ni, "getgrgid_r");
       nss_getgrent_r = __nss_lookup_function (ni, "getgrent_r");