1 files changed, 109 insertions, 0 deletions
diff --git a/libshouldbeinlibc/ugids-merge.c b/libshouldbeinlibc/ugids-merge.c
new file mode 100644
index 00000000..924e1ed9
--- /dev/null
+++ b/libshouldbeinlibc/ugids-merge.c
@@ -0,0 +1,109 @@
+/* Merging of ugids
+
+   Copyright (C) 1997 Free Software Foundation, Inc.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   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., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <stdlib.h>
+
+#include "ugids.h"
+
+static error_t
+_merge_gids (struct idvec *gids, struct idvec *gids_imp,
+	     const struct idvec *new, const struct idvec *new_imp)
+{
+  error_t err;
+  /* Gids that exist in both GIDS and NEW can only be implied in the result
+     if they are implied in both; here GIDS_STRONG and NEW_STRONG contain
+     those gids which shouldn't be implied in the result because they are not
+     in either of the sources.  */
+  struct idvec gids_strong = IDVEC_INIT;
+  struct idvec new_strong = IDVEC_INIT;
+
+  err = idvec_set (&gids_strong, gids);
+  if (! err)
+    err = idvec_set (&new_strong, new);
+  if (! err)
+    {
+      idvec_subtract (&gids_strong, gids_imp);
+      idvec_subtract (&new_strong, new_imp);
+
+      err = idvec_merge (gids, new);
+      if (! err)
+	{
+	  err = idvec_merge (gids_imp, new_imp);
+	  if (! err)
+	    {
+	      idvec_subtract (gids_imp, &gids_strong);
+	      idvec_subtract (gids_imp, &new_strong);
+	    }
+	}
+    }
+
+  idvec_fini (&gids_strong);
+  idvec_fini (&new_strong);
+
+  return err;
+}
+
+/* Add all ids in NEW to UGIDS.  */
+error_t
+ugids_merge (struct ugids *ugids, const struct ugids *new)
+{
+  error_t err;
+  err = idvec_merge (&ugids->eff_uids, &new->eff_uids);
+  if (! err)
+    err = idvec_merge (&ugids->avail_uids, &new->avail_uids);
+  if (! err)
+    err = _merge_gids (&ugids->eff_gids, &ugids->imp_eff_gids,
+		       &new->eff_gids, &new->imp_eff_gids);
+  if (! err)
+    err = _merge_gids (&ugids->avail_gids, &ugids->imp_avail_gids,
+		       &new->avail_gids, &new->imp_avail_gids);
+  return err;
+}
+
+/* Set the ids in UGIDS to those in NEW.  */
+error_t
+ugids_set (struct ugids *ugids, const struct ugids *new)
+{
+  idvec_clear (&ugids->eff_uids);
+  idvec_clear (&ugids->eff_gids);
+  idvec_clear (&ugids->avail_uids);
+  idvec_clear (&ugids->avail_gids);
+  idvec_clear (&ugids->imp_eff_gids);
+  idvec_clear (&ugids->imp_avail_gids);
+  return ugids_merge (ugids, new);
+}
+
+/* Save any effective ids in UGIDS by merging them into the available ids,
+   and removing them from the effective ones.  */
+error_t 
+ugids_save (struct ugids *ugids)
+{
+  error_t err = idvec_merge (&ugids->avail_uids, &ugids->eff_uids);
+  if (! err)
+    err = _merge_gids (&ugids->avail_gids, &ugids->imp_avail_gids,
+		       &ugids->eff_gids, &ugids->imp_eff_gids);
+  if (! err)
+    {
+      idvec_clear (&ugids->eff_uids);
+      idvec_clear (&ugids->eff_gids);
+      idvec_clear (&ugids->imp_eff_gids);
+    }
+  return err;
+}