X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fgroup-member.c;h=da015842c21e8f7a0705520abbb044b3c3080969;hb=43593319b31e6b0175b8eec4433bac744959822d;hp=9a079e29363b62d6f2079e24209cc3c404dbe471;hpb=783c1624bd8b027a65b3fba57d3213ccb1a6ddbd;p=gnulib.git

diff --git a/lib/group-member.c b/lib/group-member.c
index 9a079e293..da015842c 100644
--- a/lib/group-member.c
+++ b/lib/group-member.c
@@ -1,10 +1,12 @@
 /* group-member.c -- determine whether group id is in calling user's group list
-   Copyright (C) 1994 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   Copyright (C) 1994, 1997-1998, 2003, 2005-2006, 2009-2013 Free Software
+   Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -12,119 +14,85 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
 
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
+/* Specification.  */
+#include <unistd.h>
 
 #include <stdio.h>
 #include <sys/types.h>
+#include <stdlib.h>
 
-#ifdef STDC_HEADERS
-# include <stdlib.h>
-#endif
-
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif
+#include "xalloc-oversized.h"
 
-#include "group-member.h"
-
-char *xmalloc ();
-char *xrealloc ();
+/* Most processes have no more than this many groups, and for these
+   processes we can avoid using malloc.  */
+enum { GROUPBUF_SIZE = 100 };
 
 struct group_info
   {
-    int n_groups;
-    GETGROUPS_T *group;
+    gid_t *group;
+    gid_t groupbuf[GROUPBUF_SIZE];
   };
 
-#ifdef HAVE_GETGROUPS
-
 static void
-free_group_info (g)
-     struct group_info *g;
+free_group_info (struct group_info const *g)
 {
-  free (g->group);
-  free (g);
+  if (g->group != g->groupbuf)
+    free (g->group);
 }
 
-static struct group_info *
-get_group_info ()
+static int
+get_group_info (struct group_info *gi)
 {
-  int n_groups;
-  int n_group_slots;
-  struct group_info *gi;
-  GETGROUPS_T *group;
-
-  /* getgroups () returns the number of elements that it was able to
-     place into the array.  We simply continue to call getgroups ()
-     until the number of elements placed into the array is smaller than
-     the physical size of the array. */
-
-  group = NULL;
-  n_groups = 0;
-  n_group_slots = 0;
-  while (n_groups == n_group_slots)
-    {
-      n_group_slots += 64;
-      group = (GETGROUPS_T *) xrealloc (group,
-					n_group_slots * sizeof (GETGROUPS_T));
-      n_groups = getgroups (n_group_slots, group);
-    }
+  int n_groups = getgroups (GROUPBUF_SIZE, gi->groupbuf);
+  gi->group = gi->groupbuf;
 
-  /* In case of error, the user loses. */
   if (n_groups < 0)
     {
-      free (group);
-      return NULL;
+      int n_group_slots = getgroups (0, NULL);
+      if (0 <= n_group_slots
+          && ! xalloc_oversized (n_group_slots, sizeof *gi->group))
+        {
+          gi->group = malloc (n_group_slots * sizeof *gi->group);
+          if (gi->group)
+            n_groups = getgroups (n_group_slots, gi->group);
+        }
     }
 
-  gi = (struct group_info *) xmalloc (sizeof (*gi));
-  gi->n_groups = n_groups;
-  gi->group = group;
-
-  return gi;
+  /* In case of error, the user loses.  */
+  return n_groups;
 }
 
-#endif /* not HAVE_GETGROUPS */
-
 /* Return non-zero if GID is one that we have in our groups list.
-   If there is no getgroups function, return non-zero if GID matches
-   either of the current or effective group IDs.  */
+   Note that the groups list is not guaranteed to contain the current
+   or effective group ID, so they should generally be checked
+   separately.  */
 
 int
-group_member (gid)
-     gid_t gid;
+group_member (gid_t gid)
 {
-#ifndef HAVE_GETGROUPS
-  return ((gid == getgid ()) || (gid == getegid ()));
-#else
   int i;
   int found;
-  struct group_info *gi;
-
-  gi = get_group_info ();
-  if (gi == NULL)
-    return 0;
+  struct group_info gi;
+  int n_groups = get_group_info (&gi);
 
   /* Search through the list looking for GID. */
   found = 0;
-  for (i = 0; i < gi->n_groups; i++)
+  for (i = 0; i < n_groups; i++)
     {
-      if (gid == gi->group[i])
-	{
-	  found = 1;
-	  break;
-	}
+      if (gid == gi.group[i])
+        {
+          found = 1;
+          break;
+        }
     }
-  
-  free_group_info (gi);
+
+  free_group_info (&gi);
 
   return found;
-#endif /* HAVE_GETGROUPS */
 }
 
 #ifdef TEST
@@ -132,13 +100,13 @@ group_member (gid)
 char *program_name;
 
 int
-main (int argc, char** argv)
+main (int argc, char **argv)
 {
   int i;
 
   program_name = argv[0];
 
-  for (i=1; i<argc; i++)
+  for (i = 1; i < argc; i++)
     {
       gid_t gid;