* gpg-agent.c (main): Disable core dumps.

* cache.c: New.
* command.c (cmd_get_passphrase): Use the cache.
(cmd_clear_passphrase): Ditto.

* gpg-agent.c:  Removed unused cruft and implement the socket
based server.
(my_strusage): Take bug report address from configure.ac.
* command.c (start_command_handler): Add an argument to start as
regular server.
(start_command_handler): Enable Assuan logging.

agent/cache.c

@@ -0,0 +1,220 @@
+/* cache.c - keep a cache of passphrases
+ *	Copyright (C) 2002 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG 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 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 02111-1307, USA
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <assert.h>
+
+#include "agent.h"
+
+struct secret_data_s {
+  int  totallen; /* this includes the padding */
+  int  datalen;  /* actual data length */
+  char data[1];
+};
+
+typedef struct cache_item_s *ITEM;
+struct cache_item_s {
+  ITEM next;
+  time_t created;
+  time_t accessed;
+  int  ttl;  /* max. lifetime given in seonds */
+  struct secret_data_s *pw;
+  char key[1];
+};
+
+
+static ITEM thecache;
+
+
+static void
+release_data (struct secret_data_s *data)
+{
+   xfree (data);
+}
+
+static struct secret_data_s *
+new_data (const void *data, size_t length)
+{
+  struct secret_data_s *d;
+  int total;
+
+  /* we pad the data to 32 bytes so that it get more complicated
+     finding something out by watching allocation patterns.  This is
+     usally not possible but we better assume nothing about our
+     secure storage provider*/
+  total = length + 32 - (length % 32);
+
+  d = gcry_malloc_secure (sizeof d + total - 1);
+  if (d)
+    {
+      d->totallen = total;
+      d->datalen  = length;
+      memcpy (d->data, data, length);
+    }
+  return d;
+}
+
+
+/* check whether there are items to expire */
+static void
+housekeeping (void)
+{
+  ITEM r, rprev;
+  time_t current = time (NULL);
+
+  /* first expire the actual data */
+  for (r=thecache; r; r = r->next)
+    {
+      if (r->pw && r->accessed + r->ttl < current)
+        {
+          release_data (r->pw);
+          r->pw = NULL;
+          r->accessed = current;
+        }
+    }
+
+  /* second, make sure that we also remove them based on the created stamp so
+     that the used has to enter it from time to time.  We do this every hour */
+  for (r=thecache; r; r = r->next)
+    {
+      if (r->pw && r->created + 60*60 < current)
+        {
+          release_data (r->pw);
+          r->pw = NULL;
+          r->accessed = current;
+        }
+    }
+
+  /* third, make sure that we don't have too many items in the list.
+     Expire old and unused entries after 30 minutes */
+  for (rprev=NULL, r=thecache; r; )
+    {
+      if (!r->pw && r->accessed + 60*30 < current)
+        {
+          ITEM r2 = r->next;
+          xfree (r);
+          if (!rprev)
+            thecache = r2;
+          else
+            rprev = r2;
+          r = r2;
+        }
+      else
+        {
+          rprev = r;
+          r = r->next;
+        }
+    }
+}
+
+
+
+/* Store DATA of length DATALEN in the cache under KEY and mark it
+   with a maxiumum lifetime of TTL seconds.  If tehre is already data
+   under this key, it will be replaced.  Using a DATA of NULL deletes
+   the entry */
+int
+agent_put_cache (const char *key, const char *data, int ttl)
+{
+  ITEM r;
+
+  housekeeping ();
+
+  if (ttl < 1)
+    ttl = 60*5; /* default is 5 minutes */
+
+  for (r=thecache; r; r = r->next)
+    {
+      if ( !strcmp (r->key, key))
+        break;
+    }
+  if (r)
+    { /* replace */
+      if (r->pw)
+        {
+          release_data (r->pw);
+          r->pw = NULL;
+        }
+      if (data)
+        {
+          r->pw = new_data (data, strlen (data)+1);
+          if (!r->pw)
+            log_error ("out of core while allocating new cache item\n");
+        }
+    }
+  else if (data)
+    { /* simply insert */
+      r = xtrycalloc (1, sizeof *r + strlen (key));
+      if (!r)
+        log_error ("out of core while allocating new cache control\n");
+      else
+        {
+          strcpy (r->key, key);
+          r->created = r->accessed = time (NULL); 
+          r->ttl = ttl;
+          r->pw = new_data (data, strlen (data)+1);
+          if (!r->pw)
+            {
+              log_error ("out of core while allocating new cache item\n");
+              xfree (r);
+            }
+          else
+            {
+              r->next = thecache;
+              thecache = r;
+            }
+        }
+    }
+  return 0;
+}
+
+
+/* Try to find an item in the cache */
+const char *
+agent_get_cache (const char *key)
+{
+  ITEM r;
+  int count = 0;
+
+  housekeeping ();
+
+  /* FIXME: Returning pointers is not thread safe - add a referencense
+     counter */
+  for (r=thecache; r; r = r->next, count++)
+    {
+      if (r->pw && !strcmp (r->key, key))
+        {
+          /* put_cache does onlu put strings into the cache, so we
+             don't need the lengths */
+          r->accessed = time (NULL);
+          return r->pw->data;
+        }
+    }
+
+  return NULL;
+}
+
+
+