Changes to NSH and readline to permit NSH to work on a platform with no file system

8 files changed, 261 insertions, 30 deletions

diff --git a/apps/nshlib/Makefile b/apps/nshlib/Makefile
index 76cdac40d..a1586bb00 100644
--- a/apps/nshlib/Makefile
+++ b/apps/nshlib/Makefile
@@ -40,9 +40,14 @@ include $(APPDIR)/Make.defs
 # NSH Library
 
 ASRCS  =
-CSRCS  = nsh_init.c nsh_parse.c nsh_console.c nsh_script.c nsh_session.c
-CSRCS += nsh_fscmds.c nsh_ddcmd.c nsh_proccmds.c nsh_mmcmds.c nsh_envcmds.c
-CSRCS += nsh_dbgcmds.c
+CSRCS  = nsh_init.c nsh_parse.c nsh_console.c nsh_script.c nsh_fscmds.c
+CSRCS += nsh_ddcmd.c nsh_proccmds.c nsh_mmcmds.c nsh_envcmds.c nsh_dbgcmds.c
+
+ifeq ($(CONFIG_NFILE_STREAMS),0)
+CSRCS += nsh_stdsession.c
+else
+CSRCS += nsh_session.c
+endif
 
 ifeq ($(CONFIG_NSH_BUILTIN_APPS),y)
 CSRCS += nsh_builtin.c
@@ -105,7 +110,7 @@ endif
 endif
 
 ROOTDEPPATH = --dep-path .
-VPATH = 
+VPATH =
 
 # Build targets
 
diff --git a/apps/nshlib/nsh.h b/apps/nshlib/nsh.h
index 9f1bb40fe..bcad42b1d 100644
--- a/apps/nshlib/nsh.h
+++ b/apps/nshlib/nsh.h
@@ -68,6 +68,12 @@
 #  endif
 #endif
 
+#if CONFIG_NFILE_STREAMS == 0
+#  undef CONFIG_NSH_TELNET
+#  undef CONFIG_NSH_FILE_APPS
+#  undef CONFIG_NSH_TELNET
+#endif
+
 /* Telnetd requires networking support */
 
 #ifndef CONFIG_NET
@@ -441,7 +447,9 @@ struct nsh_parser_s
 #ifndef CONFIG_NSH_DISABLEBG
   bool    np_bg;       /* true: The last command executed in background */
 #endif
+#if CONFIG_NFILE_STREAMS > 0
   bool    np_redirect; /* true: Output from the last command was re-directed */
+#endif
   bool    np_fail;     /* true: The last command failed */
 #ifndef CONFIG_NSH_DISABLESCRIPT
   uint8_t np_ndx;      /* Current index into np_st[] */
diff --git a/apps/nshlib/nsh_builtin.c b/apps/nshlib/nsh_builtin.c
index 0819377de..59e54ae85 100644
--- a/apps/nshlib/nsh_builtin.c
+++ b/apps/nshlib/nsh_builtin.c
@@ -131,7 +131,7 @@ int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
     {
       /* The application was successfully started with pre-emption disabled.
        * In the simplest cases, the application will not have run because the
-       * the scheduler is locked.  But in the case where I/O was redirected, a 
+       * the scheduler is locked.  But in the case where I/O was redirected, a
        * proxy task ran and broke our lock.  As result, the application may
        * have aso ran if its priority was higher than than the priority of
        * this thread.
@@ -166,7 +166,7 @@ int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
            * do so.
            *
            * Also, if CONFIG_SCHED_HAVE_PARENT is defined waitpid() might fail
-           * even if task is still active:  If the I/O was re-directed by a 
+           * even if task is still active:  If the I/O was re-directed by a
            * proxy task, then the ask is a child of the proxy, and not this
            * task.  waitpid() fails with ECHILD in either case.
            */
@@ -200,7 +200,7 @@ int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
           else
             {
               /* We can't return the exact status (nsh has nowhere to put it)
-               * so just pass back zero/nonzero in a fashion that doesn't look 
+               * so just pass back zero/nonzero in a fashion that doesn't look
                * like an error.
                */
 
diff --git a/apps/nshlib/nsh_console.c b/apps/nshlib/nsh_console.c
index 1b8f5f6ac..410abc19d 100644
--- a/apps/nshlib/nsh_console.c
+++ b/apps/nshlib/nsh_console.c
@@ -1,7 +1,7 @@
 /****************************************************************************
- * apps/nshlib/nsh_serial.c
+ * apps/nshlib/nsh_console.c
  *
- *   Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -61,11 +61,13 @@
  * Private Types
  ****************************************************************************/
 
+#if CONFIG_NFILE_STREAMS > 0
 struct serialsave_s
 {
   int    cn_outfd;     /* Re-directed output file descriptor */
   FILE  *cn_outstream; /* Re-directed output stream */
 };
+#endif
 
 /****************************************************************************
  * Private Function Prototypes
@@ -80,10 +82,14 @@ static ssize_t nsh_consolewrite(FAR struct nsh_vtbl_s *vtbl,
 static int nsh_consoleoutput(FAR struct nsh_vtbl_s *vtbl,
   FAR const char *fmt, ...);
 static FAR char *nsh_consolelinebuffer(FAR struct nsh_vtbl_s *vtbl);
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
 static void nsh_consoleredirect(FAR struct nsh_vtbl_s *vtbl, int fd,
   FAR uint8_t *save);
 static void nsh_consoleundirect(FAR struct nsh_vtbl_s *vtbl,
   FAR uint8_t *save);
+#endif
+
 static void nsh_consoleexit(FAR struct nsh_vtbl_s *vtbl, int exitstatus)
   noreturn_function;
 
@@ -103,6 +109,7 @@ static void nsh_consoleexit(FAR struct nsh_vtbl_s *vtbl, int exitstatus)
  * Name: nsh_openifnotopen
  ****************************************************************************/
 
+#if CONFIG_NFILE_DESCRIPTORS > 0
 static int nsh_openifnotopen(struct console_stdio_s *pstate)
 {
   /* The stream is open in a lazy fashion.  This is done because the file
@@ -117,8 +124,10 @@ static int nsh_openifnotopen(struct console_stdio_s *pstate)
           return ERROR;
         }
     }
+
   return 0;
 }
+#endif
 
 /****************************************************************************
  * Name: nsh_closeifnotclosed
@@ -128,6 +137,7 @@ static int nsh_openifnotopen(struct console_stdio_s *pstate)
  *
  ****************************************************************************/
 
+#if CONFIG_NFILE_STREAMS > 0
 static void nsh_closeifnotclosed(struct console_stdio_s *pstate)
 {
   if (pstate->cn_outstream == OUTSTREAM(pstate))
@@ -151,6 +161,7 @@ static void nsh_closeifnotclosed(struct console_stdio_s *pstate)
       pstate->cn_outstream = NULL;
     }
 }
+#endif
 
 /****************************************************************************
  * Name: nsh_consolewrite
@@ -167,6 +178,7 @@ static ssize_t nsh_consolewrite(FAR struct nsh_vtbl_s *vtbl, FAR const void *buf
   FAR struct console_stdio_s *pstate = (FAR struct console_stdio_s *)vtbl;
   ssize_t ret;
 
+#if CONFIG_NFILE_DESCRIPTORS > 0
   /* The stream is open in a lazy fashion.  This is done because the file
    * descriptor may be opened on a different task than the stream.  The
    * actual open will then occur with the first output from the new task.
@@ -185,6 +197,10 @@ static ssize_t nsh_consolewrite(FAR struct nsh_vtbl_s *vtbl, FAR const void *buf
       dbg("[%d] Failed to send buffer: %d\n", pstate->cn_outfd, errno);
     }
   return ret;
+#else
+  printf("%s", buffer);
+  return nbytes;
+#endif
 }
 
 /****************************************************************************
@@ -197,9 +213,10 @@ static ssize_t nsh_consolewrite(FAR struct nsh_vtbl_s *vtbl, FAR const void *buf
 
 static int nsh_consoleoutput(FAR struct nsh_vtbl_s *vtbl, const char *fmt, ...)
 {
+#if CONFIG_NFILE_DESCRIPTORS > 0
   FAR struct console_stdio_s *pstate = (FAR struct console_stdio_s *)vtbl;
   va_list ap;
-  int     ret;
+  int ret;
 
   /* The stream is open in a lazy fashion.  This is done because the file
    * descriptor may be opened on a different task than the stream.  The
@@ -210,12 +227,21 @@ static int nsh_consoleoutput(FAR struct nsh_vtbl_s *vtbl, const char *fmt, ...)
    {
      return ERROR;
    }
- 
+
   va_start(ap, fmt);
   ret = vfprintf(pstate->cn_outstream, fmt, ap);
   va_end(ap);
- 
+
   return ret;
+#else
+  char dest[64 * 16];
+
+  va_start(ap, fmt);
+  vsprintf(dest, fmt, ap);
+  va_end(ap);
+
+  return printf(dest);
+#endif
 }
 
 /****************************************************************************
@@ -260,6 +286,7 @@ static void nsh_consolerelease(FAR struct nsh_vtbl_s *vtbl)
 {
   FAR struct console_stdio_s *pstate = (FAR struct console_stdio_s *)vtbl;
 
+#if CONFIG_NFILE_DESCRIPTORS > 0
   /* Close the output stream */
 
   nsh_closeifnotclosed(pstate);
@@ -269,6 +296,7 @@ static void nsh_consolerelease(FAR struct nsh_vtbl_s *vtbl)
 #ifdef CONFIG_NSH_CONDEV
   (void)fclose(pstate->cn_constream);
 #endif
+#endif
 
   /* Then release the vtable container */
 
@@ -292,7 +320,7 @@ static void nsh_consolerelease(FAR struct nsh_vtbl_s *vtbl)
  *
  *      nsh_consolerelease() will perform the clean-up when the clone is
  *      destroyed.
- *        
+ *
  *   2) Redirected foreground commands of the form:  command > xyz.txt
  *
  *      In this case:
@@ -305,9 +333,10 @@ static void nsh_consolerelease(FAR struct nsh_vtbl_s *vtbl)
  *
  ****************************************************************************/
 
+#if CONFIG_NFILE_DESCRIPTORS > 0
 static void nsh_consoleredirect(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t *save)
 {
-  FAR struct console_stdio_s     *pstate = (FAR struct console_stdio_s *)vtbl;
+  FAR struct console_stdio_s *pstate = (FAR struct console_stdio_s *)vtbl;
   FAR struct serialsave_s *ssave  = (FAR struct serialsave_s *)save;
 
   /* Case 1: Redirected foreground commands */
@@ -321,7 +350,7 @@ static void nsh_consoleredirect(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t
 
       if (pstate->cn_outstream)
         {
-          fflush(pstate->cn_outstream);          
+          fflush(pstate->cn_outstream);
         }
 
       /* Save the current fd and stream values.  These will be restored
@@ -346,6 +375,7 @@ static void nsh_consoleredirect(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t
   pstate->cn_outfd     = fd;
   pstate->cn_outstream = NULL;
 }
+#endif
 
 /****************************************************************************
  * Name: nsh_consoleundirect
@@ -355,6 +385,7 @@ static void nsh_consoleredirect(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t
  *
  ****************************************************************************/
 
+#if CONFIG_NFILE_DESCRIPTORS > 0
 static void nsh_consoleundirect(FAR struct nsh_vtbl_s *vtbl, FAR uint8_t *save)
 {
   FAR struct console_stdio_s *pstate = (FAR struct console_stdio_s *)vtbl;
@@ -364,6 +395,7 @@ static void nsh_consoleundirect(FAR struct nsh_vtbl_s *vtbl, FAR uint8_t *save)
   pstate->cn_outfd     = ssave->cn_outfd;
   pstate->cn_outstream = ssave->cn_outstream;
 }
+#endif
 
 /****************************************************************************
  * Name: nsh_consoleexit
@@ -403,9 +435,11 @@ FAR struct console_stdio_s *nsh_newconsole(void)
       pstate->cn_vtbl.write      = nsh_consolewrite;
       pstate->cn_vtbl.output     = nsh_consoleoutput;
       pstate->cn_vtbl.linebuffer = nsh_consolelinebuffer;
+      pstate->cn_vtbl.exit       = nsh_consoleexit;
+
+#if CONFIG_NFILE_STREAMS > 0
       pstate->cn_vtbl.redirect   = nsh_consoleredirect;
       pstate->cn_vtbl.undirect   = nsh_consoleundirect;
-      pstate->cn_vtbl.exit       = nsh_consoleexit;
 
       /* (Re-) open the console input device */
 
@@ -432,6 +466,7 @@ FAR struct console_stdio_s *nsh_newconsole(void)
 
       pstate->cn_outfd           = OUTFD(pstate);
       pstate->cn_outstream       = OUTSTREAM(pstate);
+#endif
     }
   return pstate;
 }
diff --git a/apps/nshlib/nsh_console.h b/apps/nshlib/nsh_console.h
index 4dc2938cb..73bab493b 100644
--- a/apps/nshlib/nsh_console.h
+++ b/apps/nshlib/nsh_console.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/nshlib/nsh_console.h
  *
- *   Copyright (C) 2007-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -74,16 +74,18 @@
 
 /* Are we using the NuttX console for I/O?  Or some other character device? */
 
-#ifdef CONFIG_NSH_CONDEV
-#  define INFD(p)      ((p)->cn_confd)
-#  define INSTREAM(p)  ((p)->cn_constream)
-#  define OUTFD(p)     ((p)->cn_confd)
-#  define OUTSTREAM(p) ((p)->cn_constream)
-#else
-#  define INFD(p)      0
-#  define INSTREAM(p)  stdin
-#  define OUTFD(p)     1
-#  define OUTSTREAM(p) stdout
+#if CONFIG_NFILE_STREAMS > 0
+#  ifdef CONFIG_NSH_CONDEV
+#    define INFD(p)      ((p)->cn_confd)
+#    define INSTREAM(p)  ((p)->cn_constream)
+#    define OUTFD(p)     ((p)->cn_confd)
+#    define OUTSTREAM(p) ((p)->cn_constream)
+#  else
+#    define INFD(p)      0
+#    define INSTREAM(p)  stdin
+#    define OUTFD(p)     1
+#    define OUTSTREAM(p) stdout
+#  endif
 #endif
 
 /****************************************************************************
@@ -107,8 +109,10 @@ struct nsh_vtbl_s
   ssize_t (*write)(FAR struct nsh_vtbl_s *vtbl, FAR const void *buffer, size_t nbytes);
   int (*output)(FAR struct nsh_vtbl_s *vtbl, const char *fmt, ...);
   FAR char *(*linebuffer)(FAR struct nsh_vtbl_s *vtbl);
+#if CONFIG_NFILE_DESCRIPTORS > 0
   void (*redirect)(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t *save);
   void (*undirect)(FAR struct nsh_vtbl_s *vtbl, FAR uint8_t *save);
+#endif
   void (*exit)(FAR struct nsh_vtbl_s *vtbl, int exitstatus) noreturn_function;
 
   /* Parser state data */
@@ -128,6 +132,7 @@ struct console_stdio_s
 
   /* NSH input/output streams */
 
+#if CONFIG_NFILE_STREAMS > 0
 #ifdef CONFIG_NSH_CONDEV
   int    cn_confd;     /* Console I/O file descriptor */
 #endif
@@ -136,6 +141,7 @@ struct console_stdio_s
   FILE  *cn_constream; /* Console I/O stream (possibly redirected) */
 #endif
   FILE  *cn_outstream; /* Output stream */
+#endif
 
   /* Line input buffer */
 
diff --git a/apps/nshlib/nsh_parse.c b/apps/nshlib/nsh_parse.c
index 3f17149f5..d449bf61e 100644
--- a/apps/nshlib/nsh_parse.c
+++ b/apps/nshlib/nsh_parse.c
@@ -821,6 +821,7 @@ static void nsh_releaseargs(struct cmdarg_s *arg)
   FAR struct nsh_vtbl_s *vtbl = arg->vtbl;
   int i;
 
+#if CONFIG_NFILE_STREAMS > 0
   /* If the output was redirected, then file descriptor should
    * be closed.  The created task has its one, independent copy of
    * the file descriptor
@@ -830,6 +831,7 @@ static void nsh_releaseargs(struct cmdarg_s *arg)
     {
       (void)close(arg->fd);
     }
+#endif
 
   /* Released the cloned vtbl instance */
 
@@ -1297,9 +1299,11 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
   FAR char *argv[MAX_ARGV_ENTRIES];
   FAR char *saveptr;
   FAR char *cmd;
+#if CONFIG_NFILE_STREAMS > 0
   FAR char *redirfile = NULL;
-  int       fd = -1;
   int       oflags = 0;
+#endif
+  int       fd = -1;
   int       argc;
   int       ret;
 
@@ -1309,7 +1313,9 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 #ifndef CONFIG_NSH_DISABLEBG
   vtbl->np.np_bg       = false;
 #endif
+#if CONFIG_NFILE_STREAMS > 0
   vtbl->np.np_redirect = false;
+#endif
 
   /* Parse out the command at the beginning of the line */
 
@@ -1388,6 +1394,7 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
     }
 #endif
 
+#if CONFIG_NFILE_STREAMS > 0
   /* Check if the output was re-directed using > or >> */
 
   if (argc > 2)
@@ -1412,6 +1419,7 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
           argc                -= 2;
         }
     }
+#endif
 
   /* Check if the maximum number of arguments was exceeded */
 
@@ -1480,7 +1488,11 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
    */
 
 #if defined(CONFIG_NSH_BUILTIN_APPS) && (!defined(CONFIG_NSH_FILE_APPS) || !defined(CONFIG_FS_BINFS))
+#if CONFIG_NFILE_STREAMS > 0
   ret = nsh_builtin(vtbl, argv[0], argv, redirfile, oflags);
+#else
+  ret = nsh_builtin(vtbl, argv[0], argv, NULL, 0);
+#endif
   if (ret >= 0)
     {
       /* nsh_builtin() returned 0 or 1.  This means that the builtin
@@ -1488,12 +1500,14 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
        * successfully).  So certainly it is not an NSH command.
        */
 
+#if CONFIG_NFILE_STREAMS > 0
       /* Free the redirected output file path */
 
       if (redirfile)
         {
           nsh_freefullpath(redirfile);
         }
+#endif
 
       /* Save the result:  success if 0; failure if 1 */
 
@@ -1506,6 +1520,7 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 
 #endif
 
+#if CONFIG_NFILE_STREAMS > 0
   /* Redirected output? */
 
   if (vtbl->np.np_redirect)
@@ -1526,6 +1541,7 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
           goto errout;
         }
     }
+#endif
 
   /* Handle the case where the command is executed in background.
    * However is app is to be started as builtin new process will
@@ -1561,12 +1577,14 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
           goto errout_with_redirect;
         }
 
+#if CONFIG_NFILE_STREAMS > 0
       /* Handle redirection of output via a file descriptor */
 
       if (vtbl->np.np_redirect)
         {
           (void)nsh_redirect(bkgvtbl, fd, NULL);
         }
+#endif
 
       /* Get the execution priority of this task */
 
@@ -1634,12 +1652,14 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
     {
       uint8_t save[SAVE_SIZE];
 
+#if CONFIG_NFILE_STREAMS > 0
       /* Handle redirection of output via a file descriptor */
 
       if (vtbl->np.np_redirect)
         {
           nsh_redirect(vtbl, fd, save);
         }
+#endif
 
       /* Then execute the command in "foreground" -- i.e., while the user waits
        * for the next prompt.  nsh_execute will return:
@@ -1650,6 +1670,7 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 
       ret = nsh_execute(vtbl, argc, argv);
 
+#if CONFIG_NFILE_STREAMS > 0
       /* Restore the original output.  Undirect will close the redirection
        * file descriptor.
        */
@@ -1658,6 +1679,7 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
         {
           nsh_undirect(vtbl, save);
         }
+#endif
 
       /* Mark errors so that it is possible to test for non-zero return values
        * in nsh scripts.
@@ -1677,11 +1699,14 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 
 #ifndef CONFIG_NSH_DISABLEBG
 errout_with_redirect:
+#if CONFIG_NFILE_STREAMS > 0
   if (vtbl->np.np_redirect)
     {
       close(fd);
     }
 #endif
+#endif
+
 errout:
   return nsh_saveresult(vtbl, true);
 }
diff --git a/apps/nshlib/nsh_session.c b/apps/nshlib/nsh_session.c
index 0c5249672..2272b1e30 100644
--- a/apps/nshlib/nsh_session.c
+++ b/apps/nshlib/nsh_session.c
@@ -94,7 +94,7 @@
  *
  * Returned Values:
  *   EXIT_SUCESS or EXIT_FAILURE is returned.
- *  
+ *
  ****************************************************************************/
 
 int nsh_session(FAR struct console_stdio_s *pstate)
@@ -150,7 +150,7 @@ int nsh_session(FAR struct console_stdio_s *pstate)
 
       else
         {
-          fprintf(pstate->cn_outstream, g_fmtcmdfailed, "nsh_session", 
+          fprintf(pstate->cn_outstream, g_fmtcmdfailed, "nsh_session",
                   "readline", NSH_ERRNO_OF(-ret));
           return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
         }
diff --git a/apps/nshlib/nsh_stdsession.c b/apps/nshlib/nsh_stdsession.c
new file mode 100644
index 000000000..11fae7db7
--- /dev/null
+++ b/apps/nshlib/nsh_stdsession.c
@@ -0,0 +1,152 @@
+/****************************************************************************
+ * apps/nshlib/nsh_stdsession.c
+ *
+ *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name Gregory Nutt nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <apps/readline.h>
+
+#include "nsh.h"
+#include "nsh_console.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nsh_session
+ *
+ * Description:
+ *   This is the common session logic or an NSH session that uses only stdin
+ *   and stdout.
+ *
+ *   This function:
+ *   - Executes the NSH logic script
+ *   - Presents a greeting
+ *   - Then provides a prompt then gets and processes the command line.
+ *   - This continues until an error occurs, then the session returns.
+ *
+ * Input Parameters:
+ *   pstate - Abstracts the underlying session.
+ *
+ * Returned Values:
+ *   EXIT_SUCESS only
+ *
+ ****************************************************************************/
+
+int nsh_session(FAR struct console_stdio_s *pstate)
+{
+  int ret;
+
+  DEBUGASSERT(pstate);
+
+  /* Present a greeting */
+
+  printf("%s", g_nshgreeting);
+
+  /* Then enter the command line parsing loop */
+
+  for (;;)
+    {
+      /* For the case of debugging the USB console... dump collected USB trace data */
+
+#ifdef CONFIG_NSH_USBDEV_TRACE
+      nsh_usbtrace();
+#endif
+
+      /* Display the prompt string */
+
+      printf("%s", g_nshprompt);
+
+      /* Get the next line of input. readline() returns EOF on end-of-file
+       * or any read failure.
+       */
+
+      ret = std_readline(pstate->cn_line, CONFIG_NSH_LINELEN);
+      if (ret != EOF)
+        {
+          /* Parse process the command */
+
+          (void)nsh_parse(&pstate->cn_vtbl, pstate->cn_line);
+        }
+
+      /* Readline normally returns the number of characters read,
+       * but will return EOF on end of file or if an error occurs.
+       * EOF will cause the session to terminate.
+       */
+
+      else
+        {
+          printf(g_fmtcmdfailed, "nsh_session", "readline", NSH_ERRNO_OF(-ret));
+          return EXIT_SUCCESS;
+        }
+    }
+
+  /* We do not get here, but this is necessary to keep some compilers happy.
+   * But others will complain that this code is not reachable.
+   */
+
+  return EXIT_SUCCESS;
+}