coreutils-6.9coreutils-6.9

1 files changed, 66 insertions, 0 deletions

diff --git a/lib/getgroups.c b/lib/getgroups.c
new file mode 100644
index 0000000..615bd4f
--- /dev/null
+++ b/lib/getgroups.c
@@ -0,0 +1,66 @@
+/* provide consistent interface to getgroups for systems that don't allow N==0
+
+   Copyright (C) 1996, 1999, 2003, 2006 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.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <stdlib.h>
+
+#include "xalloc.h"
+
+/* On at least Ultrix 4.3 and NextStep 3.2, getgroups (0, 0) always fails.
+   On other systems, it returns the number of supplemental groups for the
+   process.  This function handles that special case and lets the system-
+   provided function handle all others. */
+
+int
+getgroups (int n, GETGROUPS_T *group)
+{
+  int n_groups;
+  GETGROUPS_T *gbuf;
+  int saved_errno;
+
+#undef getgroups
+
+  if (n != 0)
+    return getgroups (n, group);
+
+  n = 20;
+  while (1)
+    {
+      /* No need to worry about address arithmetic overflow here,
+	 since the ancient systems that we're running on have low
+	 limits on the number of secondary groups.  */
+      gbuf = xmalloc (n * sizeof *gbuf);
+      n_groups = getgroups (n, gbuf);
+      if (n_groups < n)
+	break;
+      free (gbuf);
+      n += 10;
+    }
+
+  saved_errno = errno;
+  free (gbuf);
+  errno = saved_errno;
+
+  return n_groups;
+}