1 files changed, 107 insertions, 0 deletions
diff --git a/libcons/cons-lookup.c b/libcons/cons-lookup.c
new file mode 100644
index 00000000..d91cc3ce
--- /dev/null
+++ b/libcons/cons-lookup.c
@@ -0,0 +1,107 @@
+/* cons-lookup.c - Looking up virtual consoles.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   Written by Marcus Brinkmann.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd 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 GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */
+
+#include <errno.h>
+#include <malloc.h>
+#include <sys/mman.h>
+
+#include "cons.h"
+
+/* Lookup the virtual console entry with number ID in the console
+   CONS, and return it in R_VCONS_ENTRY.  If CREATE is true, the
+   virtual console entry will be created if it doesn't exist yet.  If
+   CREATE is true, and ID 0, the first free virtual console id is
+   used.  CONS must be locked.  */
+error_t
+cons_lookup (cons_t cons, int id, int create, vcons_list_t *r_vcons_entry)
+{
+  vcons_list_t previous_vcons_entry = 0;
+  vcons_list_t vcons_entry;
+
+  if (!id && !create)
+    return EINVAL;
+
+  if (id)
+    {
+      if (cons->vcons_list && cons->vcons_list->id <= id)
+        {
+	  previous_vcons_entry = cons->vcons_list;
+          while (previous_vcons_entry->next
+		 && previous_vcons_entry->next->id <= id)
+            previous_vcons_entry = previous_vcons_entry->next;
+          if (previous_vcons_entry->id == id)
+            {
+              *r_vcons_entry = previous_vcons_entry;
+              return 0;
+            }
+        }
+      else if (!create)
+	return ESRCH;
+    }
+  else
+    {
+      id = 1;
+      if (cons->vcons_list && cons->vcons_list->id == 1)
+        {
+	  previous_vcons_entry = cons->vcons_list;
+          while (previous_vcons_entry && previous_vcons_entry->id == id)
+            {
+              id++;
+              previous_vcons_entry = previous_vcons_entry->next;
+            }
+        }
+    }
+
+  vcons_entry = calloc (1, sizeof (struct vcons_list));
+  if (!vcons_entry)
+    return ENOMEM;
+
+  vcons_entry->id = id;
+  vcons_entry->vcons = NULL;
+
+  /* Insert the virtual console into the doubly linked list.  */
+  if (previous_vcons_entry)
+    {
+      vcons_entry->prev = previous_vcons_entry;
+      if (previous_vcons_entry->next)
+        {
+          previous_vcons_entry->next->prev = vcons_entry;
+          vcons_entry->next = previous_vcons_entry->next;
+        }
+      else
+	cons->vcons_last = vcons_entry;
+      previous_vcons_entry->next = vcons_entry;
+    }
+  else
+    {
+      if (cons->vcons_list)
+        {
+          cons->vcons_list->prev = vcons_entry;
+          vcons_entry->next = cons->vcons_list;
+        }
+      else
+	cons->vcons_last = vcons_entry;
+      cons->vcons_list = vcons_entry;
+    }
+
+  cons_vcons_add (cons, vcons_entry);
+  *r_vcons_entry = vcons_entry;
+  return 0;
+}