1 files changed, 80 insertions, 0 deletions
diff --git a/gl/lib/mgetgroups.c b/gl/lib/mgetgroups.c
new file mode 100644
index 000000000..8552f2639
--- /dev/null
+++ b/gl/lib/mgetgroups.c
@@ -0,0 +1,80 @@
+/* getugroups.c -- return a list of the groups a user is in
+
+   Copyright (C) 2007 Free Software Foundation.
+
+   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.  */
+
+/* Extracted from coreutils' src/id.c. */
+
+#include <config.h>
+
+#include "mgetgroups.h"
+
+#include <unistd.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include "getugroups.h"
+#include "xalloc.h"
+
+/* Like getugroups, but store the result in malloc'd storage.
+   Set *GROUPS to the malloc'd list of all group IDs of which USERNAME
+   is a member.  If GID is not -1, store it first.  GID should be the
+   group ID (pw_gid) obtained from getpwuid, in case USERNAME is not
+   listed in the groups database (e.g., /etc/groups).  Upon failure,
+   don't modify *GROUPS, set errno, and return -1.  Otherwise, return
+   the number of groups.  */
+
+int
+mgetgroups (const char *username, gid_t gid, GETGROUPS_T **groups)
+{
+  int max_n_groups;
+  int ng;
+  GETGROUPS_T *g;
+
+  max_n_groups = (username
+		  ? getugroups (0, NULL, username, gid)
+		  : getgroups (0, NULL));
+
+  /* If we failed to count groups with NULL for a buffer,
+     try again with a non-NULL one, just in case.  */
+  if (max_n_groups < 0)
+      max_n_groups = 5;
+
+  if (xalloc_oversized (max_n_groups, sizeof *g))
+    {
+      errno = ENOMEM;
+      return -1;
+    }
+
+  g = malloc (max_n_groups * sizeof *g);
+  if (g == NULL)
+    return -1;
+
+  ng = (username
+	? getugroups (max_n_groups, g, username, gid)
+	: getgroups (max_n_groups, g));
+
+  if (ng < 0)
+    {
+      int saved_errno = errno;
+      free (g);
+      errno = saved_errno;
+      return -1;
+    }
+
+  *groups = g;
+  return ng;
+}