[patch] 5.95: getgrouplist

[Tim Waugh]

Hi,

Here is a patch that makes use of getgrouplist() if it is available,
for better efficiency.

Tim.
*/

--- coreutils-5.92/m4/jm-macros.m4.getgrouplist 2005-09-25 06:57:46.000000000 
+0100
+++ coreutils-5.92/m4/jm-macros.m4      2005-10-25 14:28:45.000000000 +0100
@@ -105,6 +105,7 @@
     fchmod \
     fchown \
     ftruncate \
+    getgrouplist \
     hasmntopt \
     isascii \
     iswspace \
--- coreutils-5.92/lib/getugroups.c.getgrouplist        2005-09-22 
07:47:18.000000000 +0100
+++ coreutils-5.92/lib/getugroups.c     2005-10-25 14:28:02.000000000 +0100
@@ -23,6 +23,9 @@
 # include <config.h>
 #endif
 
+/* We do not need this code if getgrouplist(3) is available.  */
+#ifndef HAVE_GETGROUPLIST
+
 #include <sys/types.h>
 #include <stdio.h> /* grp.h on alpha OSF1 V2.0 uses "FILE *". */
 #include <grp.h>
@@ -105,3 +108,4 @@
 
   return count;
 }
+#endif /* have getgrouplist */
--- coreutils-5.92/src/id.c.getgrouplist        2005-08-11 22:02:57.000000000 
+0100
+++ coreutils-5.92/src/id.c     2005-10-25 14:30:41.000000000 +0100
@@ -253,7 +253,14 @@
   if (!username)
     max_n_groups = getgroups (0, NULL);
   else
-    max_n_groups = getugroups (0, NULL, username, gid);
+    {
+#ifdef HAVE_GETGROUPLIST
+      max_n_groups = 0;
+      getgrouplist (username, gid, NULL, &max_n_groups);
+#else
+      max_n_groups = getugroups (0, NULL, username, gid);
+#endif
+    }
 
   if (max_n_groups < 0)
     ng = -1;
@@ -263,7 +270,22 @@
       if (!username)
        ng = getgroups (max_n_groups, g);
       else
-       ng = getugroups (max_n_groups, g, username, gid);
+       {
+#ifdef HAVE_GETGROUPLIST
+         int e;
+         ng = max_n_groups;
+         while ((e = getgrouplist (username, gid, g, &ng)) == -1
+                && ng > max_n_groups)
+           {
+             max_n_groups = ng;
+             g = xrealloc (g, max_n_groups * sizeof (GETGROUPS_T));
+           }
+         if (e == -1)
+           ng = -1;
+#else
+         ng = getugroups (max_n_groups, g, username, gid);
+#endif
+       }
     }
 
   if (ng < 0)