New file. System-specific (passwd/shadow) auth functions.

+/* GNU mailutils - a suite of utilities for electronic mail
+   Copyright (C) 2002 Free Software Foundation, Inc.
+
+   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.  */
+
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <pwd.h>
+#ifdef HAVE_SHADOW_H
+# include <shadow.h>
+#endif
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif
+
+#include <mailutils/list.h>
+#include <mailutils/iterator.h>
+#include <mailutils/mailbox.h>
+#include <mailutils/argp.h>
+#include <mailutils/mu_auth.h>
+
+/* System database */
+int
+mu_auth_system (void *return_data, struct passwd *pw)
+{
+  char *mailbox_name;
+  int rc;
+  
+  if (!pw)
+    return 1;
+
+  mailbox_name = malloc (strlen (mu_path_maildir) +
+			 strlen (pw->pw_name) + 1);
+  if (!mailbox_name)
+    return 1;
+
+  sprintf (mailbox_name, "%s%s", mu_path_maildir, pw->pw_name);
+  
+  rc = mu_auth_data_alloc ((struct mu_auth_data **) return_data,
+			   pw->pw_name,
+			   pw->pw_passwd,
+			   pw->pw_uid,
+			   pw->pw_gid,
+			   pw->pw_gecos,
+			   pw->pw_dir,
+			   pw->pw_shell,
+			   mailbox_name,
+			   1);
+  free (mailbox_name);
+  return rc;
+}
+
+int
+mu_auth_system_by_name (void *return_data, void *key,
+			void *unused_func_data, void *unused_call_data)
+{
+  if (!key)
+    {
+      errno = EINVAL;
+      return 1;
+    }
+  return mu_auth_system (return_data, getpwnam (key));
+}
+
+int
+mu_auth_system_by_uid (void *return_data, void *key,
+		       void *unused_func_data, void *unused_call_data)
+{
+  if (!key)
+    {
+      errno = EINVAL;
+      return 1;
+    }
+  return mu_auth_system (return_data, getpwuid (*(uid_t*) key));
+}
+
+int
+mu_authenticate_generic (void *ignored_return_data,
+			 void *key,
+			 void *ignored_func_data,
+			 void *call_data)
+{
+  struct mu_auth_data *auth_data = key;
+  char *pass = call_data;
+
+  return !auth_data
+    || !auth_data->passwd
+    || strcmp (auth_data->passwd, crypt (pass, auth_data->passwd));
+}
+
+/* Called only if generic fails */
+int
+mu_authenticate_system (void *ignored_return_data,
+			void *key,
+			void *ignored_func_data,
+			void *call_data)
+{
+  struct mu_auth_data *auth_data = key;
+  char *pass = call_data;
+
+#ifdef HAVE_SHADOW_H
+  if (auth_data)
+    {
+      struct spwd *spw;
+      spw = getspnam (auth_data->name);
+      if (spw)
+	return strcmp (spw->sp_pwdp, crypt (pass, spw->sp_pwdp));
+    }
+#endif
+  return 1;
+}
+
+
+struct mu_auth_module mu_auth_system_module = {
+  "system",
+  NULL,
+  mu_authenticate_system,
+  NULL,
+  mu_auth_system_by_name,
+  NULL,
+  mu_auth_system_by_uid,
+  NULL
+};
+
+
+struct mu_auth_module mu_auth_generic_module = {
+  "generic",
+  NULL,
+  mu_authenticate_generic,
+  NULL,
+  mu_auth_nosupport,
+  NULL,
+  mu_auth_nosupport,
+  NULL
+};
+