2009-03-27 Sebastian Huber <sebastian.huber@embedded-brains.de>

	* Makefile.am, preinstall.am, libmisc/Makefile.am,
	libmisc/shell/shell.c, libmisc/shell/shell.h, telnetd/check_passwd.c,
	telnetd/telnetd.c, telnetd/telnetd.h:
	Generalized login check.
	* libmisc/shell/login.h, libmisc/shell/login_check.c,
	libmisc/shell/login_prompt.c: New files.
	* libmisc/stackchk/check.c: Changed format for blown stack message.
	* libcsupport/src/libio_sockets.c: Removed superfluous cast.
	* libnetworking/rtems/ftpfs.h: Documentation.

3 files changed, 275 insertions, 281 deletions

diff --git a/cpukit/telnetd/check_passwd.c b/cpukit/telnetd/check_passwd.c
index 8486058fa0..46059e8936 100644
--- a/cpukit/telnetd/check_passwd.c
+++ b/cpukit/telnetd/check_passwd.c
@@ -1,23 +1,18 @@
 /* $Id$ */
 
-/* Read a password, encrypt it and compare to the encrypted 
- * password in the TELNETD_PASSWD environment variable.
- * No password is required if TELNETD_PASSWD is unset
- */
-
-/* 
+/*
  * Authorship
  * ----------
  * This software was created by
  *     Till Straumann <strauman@slac.stanford.edu>, 2003-2007
  * 	   Stanford Linear Accelerator Center, Stanford University.
- * 
+ *
  * Acknowledgement of sponsorship
  * ------------------------------
  * This software was produced by
  *     the Stanford Linear Accelerator Center, Stanford University,
  * 	   under Contract DE-AC03-76SFO0515 with the Department of Energy.
- * 
+ *
  * Government disclaimer of liability
  * ----------------------------------
  * Neither the United States nor the United States Department of Energy,
@@ -26,18 +21,18 @@
  * completeness, or usefulness of any data, apparatus, product, or process
  * disclosed, or represents that its use would not infringe privately owned
  * rights.
- * 
+ *
  * Stanford disclaimer of liability
  * --------------------------------
  * Stanford University makes no representations or warranties, express or
  * implied, nor assumes any liability for the use of this software.
- * 
+ *
  * Stanford disclaimer of copyright
  * --------------------------------
  * Stanford University, owner of the copyright, hereby disclaims its
  * copyright and all other rights in this software.  Hence, anyone may
- * freely use it for any purpose without restriction.  
- * 
+ * freely use it for any purpose without restriction.
+ *
  * Maintenance of notices
  * ----------------------
  * In the interest of clarity regarding the origin and status of this
@@ -46,13 +41,23 @@
  * or distributed by the recipient and are to be affixed to any copy of
  * software made or distributed by the recipient that contains a copy or
  * derivative of this software.
- * 
+ *
  * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
- */ 
+ *
+ * Copyright (c) 2009
+ * embedded brains GmbH
+ * Obere Lagerstr. 30
+ * D-82178 Puchheim
+ * Germany
+ * <rtems@embedded-brains.de>
+ *
+ * Modified by Sebastian Huber <sebastian.huber@embedded-brains.de>.
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
 
-#if !defined(INSIDE_TELNETD) && !defined(__rtems__)
-#include <crypt.h>
-#endif
 #include <termios.h>
 #include <errno.h>
 #include <stdio.h>
@@ -61,140 +66,41 @@
 #include <string.h>
 #include <syslog.h>
 
-#include "passwd.h"
+#include <rtems/telnetd.h>
 
-/* rtems has global filedescriptors but per-thread stdio streams... */
-#define STDI_FD fileno(stdin)
-#define MAXPASSRETRY	3
-
-extern char *__des_crypt_r(char *, char*, char*, int);
+#include "passwd.h"
 
-#if !defined(INSIDE_TELNETD)
-#define sockpeername(s,b,sz) (-1)
-#endif
+char *__des_crypt_r( const char *, const char *, char *, int);
 
-#if defined(INSIDE_TELNETD)
-static
-#endif
-int check_passwd(char *peername)
+/**
+ * @brief Standard Telnet login check that uses DES to encrypt the passphrase.
+ *
+ * Takes a @a passphrase, encrypts it and compares it to the encrypted
+ * passphrase in the @c TELNETD_PASSWD environment variable.  No password is
+ * required if @c TELNETD_PASSWD is unset.  The argument @a user is ignored.
+ */
+bool rtems_telnetd_login_check(
+  const char *user,
+  const char *passphrase
+)
 {
-  char			*pw;
-  int			rval = -1, tmp, retries;
-  struct termios	t,told;
-  int			restore_flags = 0;
-  char			buf[30], cryptbuf[21];
-  char			salt[3];
-
-  if ( !(pw=getenv("TELNETD_PASSWD")) || 0 == strlen(pw) )
-#ifdef TELNETD_DEFAULT_PASSWD
-    pw = TELNETD_DEFAULT_PASSWD;
-#else
-    return 0;
-#endif
-
-  if ( tcgetattr(STDI_FD, &t) ) {
-    perror("check_passwd(): tcgetattr");
-    goto done;	
+  char *pw = getenv( "TELNETD_PASSWD");
+  char cryptbuf [21];
+  char salt [3];
+
+  if (pw == NULL || strlen( pw) == 0) {
+    #ifdef TELNETD_DEFAULT_PASSWD
+      pw = TELNETD_DEFAULT_PASSWD;
+    #else
+      return true;
+    #endif
   }
-  told = t;
-  t.c_lflag &= ~ECHO;
-  t.c_lflag &= ~ICANON;
-  t.c_cc[VTIME] = 255;
-  t.c_cc[VMIN]  = 0;
 
-  strncpy(salt,pw,2);
-  salt[2]=0;
-
-  if ( tcsetattr(STDI_FD, TCSANOW, &t) ) {
-    perror("check_passwd(): tcsetattr");
-    goto done;	
-  }
-  restore_flags = 1;
+  strncpy( salt, pw, 2);
+  salt [2] = '\0';
 
-  /* Here we ask for the password... */
-  for ( retries = MAXPASSRETRY; retries > 0; retries-- ) {
-    fflush(stdin);
-    fprintf(stderr,"Password:");
-    fflush(stderr);
-    if ( 0 == fgets(buf,sizeof(buf),stdin) ) {
-      /* Here comes an ugly hack:
-       * The termios driver's 'read()' handler
-       * returns 0 to the c library's fgets if
-       * it times out. 'fgets' interprets this
-       * (correctly) as EOF, a condition we want
-       * to undo since it's not really true since
-       * we really have a read error (termios bug??)
-       *
-       * As a workaround we push something back and
-       * read it again. This should simply reset the
-       * EOF condition.
-       */
-      if (ungetc('?',stdin) >= 0)
-        fgetc(stdin);
-      goto done;
-    }
-    fputc('\n',stderr);
-    tmp = strlen(buf);
-    while ( tmp > 0 && ('\n' == buf[tmp-1] || '\r' == buf[tmp-1]) ) {
-      buf[--tmp]=0;
-    }
-    if ( !strcmp(__des_crypt_r(buf, salt, cryptbuf, sizeof(cryptbuf)), pw) ) {
-      rval = 0;
-      break;
-    }
-    fprintf(stderr,"Incorrect Password.\n");
-    sleep(2);
-  }
-
-  if ( 0 == retries ) {
-    syslog( LOG_AUTHPRIV | LOG_WARNING,
-      "telnetd: %i wrong passwords entered from %s",
-      MAXPASSRETRY,
-      peername ? peername : "<UNKNOWN>");
-  }
-
-done:
-  /* what to do if restoring the flags fails?? */
-  if (restore_flags)
-    tcsetattr(STDI_FD, TCSANOW, &told);
-  
-  if (rval) {
-    sleep(2);
-  }
-  return rval;
+  return strcmp(
+    __des_crypt_r( passphrase, salt, cryptbuf, sizeof( cryptbuf)),
+    pw
+  ) == 0;
 }
-
-#if !defined(INSIDE_TELNETD) && !defined(__rtems__)
-int
-main(int argc, char **argv)
-{
-char *str, *enc=0;
-int   ch;
-
-while ( (ch=getopt(argc, argv, "g:")) > 0 ) {
-  switch (ch) {
-    default:
-      fprintf(stderr,"Unknown option\n");
-    return(1);
-
-    case 'g':
-      printf("Generated encrypted password: '%s'\n", (enc=crypt(optarg,"td")));
-    break;
-      
-  }
-}
-if (argc>optind && !enc) {
-  enc=argv[optind];
-}
-if (enc) {
-  str = malloc(strlen(enc) + 30);
-  sprintf(str,"TELNETD_PASSWD=%s",enc);
-  putenv(str);
-}
-if (check_passwd(-1)) {
-  fprintf(stderr,"check_passwd() failed\n");
-}
-return 0;
-}
-
-#endif
diff --git a/cpukit/telnetd/telnetd.c b/cpukit/telnetd/telnetd.c
index 7593fdca46..772b62af08 100644
--- a/cpukit/telnetd/telnetd.c
+++ b/cpukit/telnetd/telnetd.c
@@ -5,7 +5,7 @@
  *
  *  Author: 17,may 2001
  *
- *   WORK: fernando.ruiz@ctv.es 
+ *   WORK: fernando.ruiz@ctv.es
  *   HOME: correo@fernando-ruiz.com
  *
  * After start the net you can start this daemon.
@@ -15,7 +15,7 @@
  *
  * With register_telnetd() you add a new command in the shell to start
  * this daemon interactively. (Login in /dev/console of course)
- * 
+ *
  * Sorry but OOB is not still implemented. (This is the first version)
  *
  * Till Straumann <strauman@slac.stanford.edu>
@@ -23,11 +23,20 @@
  *    possible to have 'telnetd' run an arbitrary 'shell'
  *    program.
  *
- *  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.
- * 
- *  $Id$
+ * Copyright (c) 2009
+ * embedded brains GmbH
+ * Obere Lagerstr. 30
+ * D-82178 Puchheim
+ * Germany
+ * <rtems@embedded-brains.de>
+ *
+ * Modified by Sebastian Huber <sebastian.huber@embedded-brains.de>.
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ *
+ * $Id$
  */
 
 #ifdef HAVE_CONFIG_H
@@ -73,10 +82,7 @@ typedef union uni_sa {
 
 static int sockpeername(int sock, char *buf, int bufsz);
 
-static int initialize_telnetd(void);
-static int telnetd_askForPassword;
-
-void * telnetd_dflt_spawn(
+void *telnetd_dflt_spawn(
   const char *name,
   unsigned priority,
   unsigned stackSize,
@@ -85,18 +91,15 @@ void * telnetd_dflt_spawn(
 );
 
 /***********************************************************/
-rtems_id            telnetd_task_id                 = 0;
-uint32_t            telnetd_stack_size              = 32000;
-rtems_task_priority telnetd_task_priority           = 0;
-bool                telnetd_remain_on_caller_stdio  = false;
-void                (*telnetd_shell)(char *, void*) = 0;
-void                *telnetd_shell_arg              = NULL;
-void *              (*telnetd_spawn_task)(
+static rtems_id telnetd_task_id = RTEMS_ID_NONE;
+
+void *(*telnetd_spawn_task)(
   const char *,
   unsigned,
   unsigned,
   void (*)(void*),
-  void *) = telnetd_dflt_spawn;
+  void *
+) = telnetd_dflt_spawn;
 
 static char *grab_a_Connection(
   int des_socket,
@@ -178,14 +181,6 @@ static int sockpeername(int sock, char *buf, int bufsz)
   return rval;
 }
 
-#if 1
-#define INSIDE_TELNETD
-#include "check_passwd.c"
-#else
-#define check_passwd(arg) 0
-#endif
-
-
 static void
 spawned_shell(void *arg);
 
@@ -203,7 +198,7 @@ rtems_task_telnetd(void *task_argument)
 
   if ((des_socket=socket(PF_INET,SOCK_STREAM,0))<0) {
     perror("telnetd:socket");
-    telnetd_task_id=0;
+    telnetd_task_id = RTEMS_ID_NONE;
     rtems_task_delete(RTEMS_SELF);
   };
   setsockopt(des_socket,SOL_SOCKET,SO_KEEPALIVE,&i,sizeof(i));
@@ -215,13 +210,13 @@ rtems_task_telnetd(void *task_argument)
   if ((bind(des_socket,&srv.sa,size_adr))<0) {
     perror("telnetd:bind");
     close(des_socket);
-    telnetd_task_id=0;
+    telnetd_task_id = RTEMS_ID_NONE;
     rtems_task_delete(RTEMS_SELF);
   };
   if ((listen(des_socket,5))<0) {
     perror("telnetd:listen");
           close(des_socket);
-    telnetd_task_id=0;
+    telnetd_task_id = RTEMS_ID_NONE;
     rtems_task_delete(RTEMS_SELF);
   };
 
@@ -229,28 +224,51 @@ rtems_task_telnetd(void *task_argument)
    * was started from the console anyways..
    */
   do {
-    if ( telnetd_remain_on_caller_stdio ) {
-      char device_name[32];
-      ttyname_r( 1, device_name, sizeof(device_name) );
-      if ( !telnetd_askForPassword || (0 == check_passwd(arg->peername)) )
-	telnetd_shell(device_name, telnetd_shell_arg);
+    if (rtems_telnetd_config.keep_stdio) {
+      bool start = true;
+      char device_name [32];
+
+      ttyname_r( 1, device_name, sizeof( device_name));
+      if (rtems_telnetd_config.login_check != NULL) {
+        start = rtems_shell_login_prompt(
+          stdin,
+          stderr,
+          device_name,
+          rtems_telnetd_config.login_check
+        );
+      }
+      if (start) {
+        rtems_telnetd_config.command( device_name, arg->arg);
+      } else {
+        syslog(
+          LOG_AUTHPRIV | LOG_WARNING,
+          "telnetd: to many wrong passwords entered from %s",
+          device_name
+        );
+      }
     } else {
       devname = grab_a_Connection(des_socket, &srv, peername, sizeof(peername));
 
       if ( !devname ) {
-	/* if something went wrong, sleep for some time */
-	sleep(10);
-	continue;
+        /* if something went wrong, sleep for some time */
+        sleep(10);
+        continue;
       }
 
       arg = malloc( sizeof(*arg) );
 
       arg->devname = devname;
-      arg->arg = telnetd_shell_arg;
+      arg->arg = rtems_telnetd_config.arg;
       strncpy(arg->peername, peername, sizeof(arg->peername));
 
-      if ( !telnetd_spawn_task( &devname[5], telnetd_task_priority,
-               telnetd_stack_size, spawned_shell, arg) ) {
+      telnetd_task_id = (rtems_id) telnetd_spawn_task(
+        devname,
+        rtems_telnetd_config.priority,
+        rtems_telnetd_config.stack_size,
+        spawned_shell,
+        arg
+      );
+      if (telnetd_task_id == RTEMS_ID_NONE) {
         FILE *dummy;
 
         if ( telnetd_spawn_task != telnetd_dflt_spawn ) {
@@ -273,83 +291,71 @@ rtems_task_telnetd(void *task_argument)
     }
   } while(1);
 
-  /* TODO: how to free the connection semaphore? But then - 
+  /* TODO: how to free the connection semaphore? But then -
    *       stopping the daemon is probably only needed during
    *       development/debugging.
    *       Finalizer code should collect all the connection semaphore
    *       counts and eventually clean up...
    */
   close(des_socket);
-  telnetd_task_id=0;
-}
-
-/***********************************************************/
-static int initialize_telnetd(void) {
-  
-  if (telnetd_task_id         ) return RTEMS_RESOURCE_IN_USE;
-  if (telnetd_stack_size<=0   ) telnetd_stack_size   =32000;
-
-  if ( !telnetd_spawn_task("TNTD", telnetd_task_priority,
-          RTEMS_MINIMUM_STACK_SIZE, rtems_task_telnetd, 0) ) {
-    return -1;
-  }
-  return 0;
+  telnetd_task_id = RTEMS_ID_NONE;
 }
 
-/***********************************************************/
-int rtems_telnetd_initialize(
-  void               (*cmd)(char *, void *),
-  void                *arg,
-  bool                 remainOnCallerSTDIO,
-  size_t               stack,
-  rtems_task_priority  priority,
-  bool                 askForPassword
-)
+rtems_status_code rtems_telnetd_initialize( void)
 {
-  rtems_status_code sc;
+  rtems_status_code sc = RTEMS_SUCCESSFUL;
 
-#if 0
-  printf("This is rtems-telnetd (modified by Till Straumann)\n");
-  printf("$Id$\n");
-  printf("Release $Name$\n");
-#endif
-
-  if ( !telnetd_shell && !cmd ) {
-    fprintf(stderr,"startTelnetd(): setup error - NO SHELL; bailing out\n");
-    return 1;
+  if (telnetd_task_id != RTEMS_ID_NONE) {
+    fprintf(stderr, "telnetd already started\n");
+    return RTEMS_RESOURCE_IN_USE;
   }
 
-  if (telnetd_task_id) {
-    fprintf(stderr,"ERROR:telnetd already started\n");
-    return 1;
-  };
+  if (rtems_telnetd_config.command == NULL) {
+    fprintf(stderr, "telnetd setup with invalid command\n");
+    return RTEMS_IO_ERROR;
+  }
 
   if ( !telnet_pty_initialize() ) {
-    fprintf(stderr,"PTY driver probably not properly registered\n");
-    return 1;
+    fprintf(stderr, "telnetd cannot initialize PTY driver\n");
+    return RTEMS_IO_ERROR;
   }
 
-  telnetd_askForPassword = askForPassword;
+  /* Check priority */
+  if (rtems_telnetd_config.priority <= 0) {
+    rtems_telnetd_config.priority = rtems_bsdnet_config.network_task_priority;
+  }
+  if (rtems_telnetd_config.priority < 2) {
+    rtems_telnetd_config.priority = 100;
+  }
 
-  if (cmd)
-    telnetd_shell = cmd;
-  telnetd_shell_arg     = arg;
-  telnetd_stack_size    = stack;
-  if ( !priority ) {
-    priority = rtems_bsdnet_config.network_task_priority;
+  /* Check stack size */
+  if (rtems_telnetd_config.stack_size <= 0) {
+    rtems_telnetd_config.stack_size = 32 * 1024;
   }
-  if ( priority < 2 )
-    priority = 100;
-  telnetd_task_priority          = priority;
-  telnetd_remain_on_caller_stdio = remainOnCallerSTDIO;
-
-  sc = initialize_telnetd();
-  if (sc != RTEMS_SUCCESSFUL) return sc;
-
-  if ( !telnetd_remain_on_caller_stdio )
-    fprintf(stderr, "rtems_telnetd() started with stacksize=%u,priority=%d\n",
-      (unsigned)telnetd_stack_size,(int)telnetd_task_priority);
-  return 0;
+
+  /* Spawn task */
+  telnetd_task_id = (rtems_id) telnetd_spawn_task(
+    "TNTD",
+    rtems_telnetd_config.priority,
+    RTEMS_MINIMUM_STACK_SIZE,
+    rtems_task_telnetd,
+    0
+  );
+  if (telnetd_task_id == RTEMS_ID_NONE) {
+    return RTEMS_IO_ERROR;
+  }
+
+  /* Print status */
+  if (!rtems_telnetd_config.keep_stdio) {
+    fprintf(
+      stderr,
+      "telnetd started with stacksize = %u and priority = %d\n",
+      (unsigned) rtems_telnetd_config.stack_size,
+      (unsigned) rtems_telnetd_config.priority
+    );
+  }
+
+  return RTEMS_SUCCESSFUL;
 }
 
 /* utility wrapper */
@@ -361,6 +367,8 @@ spawned_shell(void *targ)
   FILE                *ostd[3]={ stdin, stdout, stderr };
   int                  i=0;
   struct shell_args  *arg = targ;
+  bool login_failed = false;
+  bool start = true;
 
   sc=rtems_libio_set_private_env();
 
@@ -397,13 +405,31 @@ spawned_shell(void *targ)
   #endif
 
   /* call their routine */
-  if ( !telnetd_askForPassword || (0 == check_passwd(arg->peername)) )
-    telnetd_shell(arg->devname, arg->arg);
+  if (rtems_telnetd_config.login_check != NULL) {
+    start = rtems_shell_login_prompt(
+      stdin,
+      stderr,
+      arg->devname,
+      rtems_telnetd_config.login_check
+    );
+    login_failed = !start;
+  }
+  if (start) {
+    rtems_telnetd_config.command( arg->devname, arg->arg);
+  }
 
   stdin  = ostd[0];
   stdout = ostd[1];
   stderr = ostd[2];
 
+  if (login_failed) {
+    syslog(
+      LOG_AUTHPRIV | LOG_WARNING,
+      "telnetd: to many wrong passwords entered from %s",
+      arg->peername
+    );
+  }
+
 cleanup:
   release_a_Connection(arg->devname, arg->peername, nstd, i);
   free(arg);
@@ -433,7 +459,7 @@ void *
 telnetd_dflt_spawn(const char *name, unsigned int priority, unsigned int stackSize, void (*fn)(void *), void* fnarg)
 {
   rtems_status_code        sc;
-  rtems_id                 task_id;
+  rtems_id                 task_id = RTEMS_ID_NONE;
   char                     nm[4] = {'X','X','X','X' };
   struct wrap_delete_args *pwa = malloc(sizeof(*pwa));
 
@@ -441,7 +467,7 @@ telnetd_dflt_spawn(const char *name, unsigned int priority, unsigned int stackSi
 
   if ( !pwa ) {
     perror("Telnetd: no memory\n");
-    return 0;
+    return (void *) RTEMS_ID_NONE;
   }
 
   pwa->t = fn;
@@ -460,9 +486,9 @@ telnetd_dflt_spawn(const char *name, unsigned int priority, unsigned int stackSi
       (rtems_task_argument)pwa))) {
         free(pwa);
         rtems_error(sc,"Telnetd: spawning task failed");
-        return 0;
+        return (void *) RTEMS_ID_NONE;
   }
-  return (void*)task_id;
+  return (void *) task_id;
 }
 
 /* convenience routines for CEXP (retrieve stdio descriptors
diff --git a/cpukit/telnetd/telnetd.h b/cpukit/telnetd/telnetd.h
index db0ea94162..cb1ee6aa44 100644
--- a/cpukit/telnetd/telnetd.h
+++ b/cpukit/telnetd/telnetd.h
@@ -3,49 +3,111 @@
  *  May 2001
  *  Reworked by Till Straumann and .h overhauled by Joel Sherrill.
  *
- *  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.
+ * Copyright (c) 2009
+ * embedded brains GmbH
+ * Obere Lagerstr. 30
+ * D-82178 Puchheim
+ * Germany
+ * <rtems@embedded-brains.de>
  *
- *  $Id$
+ * Modified by Sebastian Huber <sebastian.huber@embedded-brains.de>.
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ *
+ * $Id$
  */
 
 #ifndef _RTEMS_TELNETD_H
 #define _RTEMS_TELNETD_H
 
+#include <rtems.h>
+#include <rtems/login.h>
+
 #ifdef __cplusplus
 extern "C" {
-#endif	
+#endif
+
+bool rtems_telnetd_login_check(
+  const char *user,
+  const char *passphrase
+);
 
 /**
- *  This method initializes the telnetd subsystem.
- *
- *  @param[in] cmd is the function which is the "shell" telnetd invokes
- *  @param[in] arg is the context pointer to cmd
- *  @param[in] remainOnCallerSTDIO is set to TRUE if telnetd takes over the
- *    standard in, out and error associated with task.  In this case,
- *    it will be NOT be listening on any sockets.  When this parameters
- *    is FALSE the telnetd will create other tasks for the shell
- *    which listen on sockets.
- *  @param[in] stack is stack size of spawned task.
- *  @param[in] priority is the initial priority of spawned task(s).  If
- *    this parameter is less than 2, then the default priority of 100 is used.
- *  @param[in] askForPassword is set to TRUE if telnetd is to ask for a
- *    password. This is set to FALSE to invoke "cmd" with no password check.
- *    This may be OK if "cmd" includes its own check and indeed the RTEMS Shell
- *    uses a login with a user name and password so this is the usual case.
+ * @brief Telnet command type.
  */
-int rtems_telnetd_initialize(
-  void               (*cmd)(char *, void *),
-  void                *arg,
-  bool                 remainOnCallerSTDIO,
-  size_t               stack,
-  rtems_task_priority  priority,
-  bool                 askForPassword
+typedef void (*rtems_telnetd_command)(
+  char * /* device name */,
+  void * /* arg */
 );
 
+/**
+ * @brief Telnet configuration structure.
+ */
+typedef struct {
+  /**
+   * @brief Function invoked for each Telnet connection.
+   *
+   * The first parameter contains the device name.  The second parameter
+   * contains the argument pointer of this configuration table.
+   */
+  rtems_telnetd_command command;
+
+  /**
+   * @brief Argument for command function.
+   */
+  void *arg;
+
+  /**
+   * @brief Task priority.
+   *
+   * If this parameter is equal to zero, then the priority of network task is
+   * used or 100 if this priority is less than two.
+   */
+  rtems_task_priority priority;
+
+  /**
+   * @brief Task stack size.
+   */
+  size_t stack_size;
+
+  /**
+   * @brief Login check function.
+   *
+   * Method used for login checks.  Use @c NULL to disable a login check.
+   */
+  rtems_login_check login_check;
+
+  /**
+   * @brief Keep standard IO of the caller.
+   *
+   * Telnet takes over the standard input, output and error associated with
+   * task, if this parameter is set to @c true.  In this case, it will @b not
+   * listen on any sockets.  When this parameter is @c false, Telnet will
+   * create other tasks for the shell which listen on sockets.
+   */
+  bool keep_stdio;
+} rtems_telnetd_config_table;
+
+/**
+ * @brief Telnet configuration.
+ *
+ * The application must provide this configuration table.  It is used by
+ * rtems_telnetd_initialize() to configure the Telnet subsystem.  Do not modify
+ * the entries after the intialization since it is used internally.
+ */
+extern rtems_telnetd_config_table rtems_telnetd_config;
+
+/**
+ * @brief Initializes the Telnet subsystem.
+ *
+ * Uses the application provided @ref rtems_telnetd_config configuration table.
+ */
+rtems_status_code rtems_telnetd_initialize( void);
+
 #ifdef __cplusplus
 }
-#endif	
+#endif
 
 #endif