1 files changed, 73 insertions, 0 deletions
diff --git a/grp/initgroups.c b/grp/initgroups.c
new file mode 100644
index 0000000000..5af1926742
--- /dev/null
+++ b/grp/initgroups.c
@@ -0,0 +1,73 @@
+/* Copyright (C) 1989, 1991, 1993 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <unistd.h>
+#include <string.h>
+#include <grp.h>
+#include <limits.h>
+#include <sys/types.h>
+
+
+/* Initialize the group set for the current user
+   by reading the group database and using all groups
+   of which USER is a member.  Also include GROUP.  */
+int
+DEFUN(initgroups, (user, group),
+      CONST char *user AND gid_t group)
+{
+#ifdef NGROUPS_MAX
+#if NGROUPS_MAX == 0
+  return 0;
+#else
+  static PTR info = NULL;
+  register FILE *stream;
+  register struct group *g;
+  gid_t groups[NGROUPS_MAX];
+  register size_t n;
+
+  if (info == NULL)
+    {
+      info = __grpalloc();
+      if (info == NULL)
+	return -1;
+    }
+
+  stream = __grpopen();
+  if (stream == NULL)
+    return -1;
+
+  n = 0;
+  groups[n++] = group;
+
+  while (n < NGROUPS_MAX && (g = __grpread(stream, info)) != NULL)
+    if (g->gr_gid != group)
+      {
+	register char **m;
+
+	for (m = g->gr_mem; *m != NULL; ++m)
+	  if (!strcmp(*m, user))
+	    groups[n++] = g->gr_gid;
+      }
+
+  return setgroups(n, groups);
+#endif
+#else
+  return 0;
+#endif
+}