Fix NSH redirection hang

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3326 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -1485,3 +1485,17 @@
 
 	* NSH: 'mem' command renamed to 'free'.  Output is now more similar to the
 	  Linux 'free' command.
+	* NSH: Correct a redirection bug in NSH.  The following would not work; it
+	  resulted in a hang after the 'cat /dev/fifo':
+
+	    nsh> mkfile /dev/fifo
+	    nsh> cd /tmp             # /tmp is a mounted RAM disk
+	    nsh> cat /dev/fifo > test.txt &
+	    nsh> echo "This is a test" > /dev/fifo
+
+	  The error was caused because (1) there was a path that resulted in stdout
+	  being closed (the "hang") and also (2) the 'cat' command was always outputting
+	  to stdout, not to the redirected file descriptor.  Now:
+
+	    nsh> cat test.txt
+	    This is a test

Documentation/NuttX.html

@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
-      <p>Last Updated: February 27, 2011</p>
+      <p>Last Updated: February 28, 2011</p>
     </td>
   </tr>
 </table>
@@ -2087,6 +2087,20 @@ nuttx-5.19 2011-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
     * NSH: 'mem' command renamed to 'free'.  Output is now more similar to the
       Linux 'free' command.
+    * NSH: Correct a redirection bug in NSH.  The following would not work; it
+      resulted in a hang after the 'cat /dev/fifo':
+
+        nsh> mkfile /dev/fifo
+        nsh> cd /tmp             # /tmp is a mounted RAM disk
+        nsh> cat /dev/fifo > test.txt &
+        nsh> echo "This is a test" > /dev/fifo
+
+      The error was caused because (1) there was a path that resulted in stdout
+      being closed (the "hang") and also (2) the 'cat' command was always outputting
+      to stdout, not to the redirected file descriptor.  Now:
+
+        nsh> cat test.txt
+        This is a test
 
 pascal-2.1 2011-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 

examples/nsh/nsh.h

@@ -177,6 +177,7 @@
 
 #define nsh_clone(v)           (v)->clone(v)
 #define nsh_release(v)         (v)->release(v)
+#define nsh_write(v,b,n)       (v)->write(v,b,n)
 #define nsh_linebuffer(v)      (v)->linebuffer(v)
 #define nsh_redirect(v,f,s)    (v)->redirect(v,f,s)
 #define nsh_undirect(v,s)      (v)->undirect(v,s)
@@ -255,6 +256,7 @@ struct nsh_vtbl_s
   void (*addref)(FAR struct nsh_vtbl_s *vtbl);
   void (*release)(FAR struct nsh_vtbl_s *vtbl);
 #endif
+  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);
   void (*redirect)(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t *save);

examples/nsh/nsh_fscmds.c

@@ -457,7 +457,7 @@ int cmd_cat(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 
                       while (nbyteswritten < nbytesread)
                         {
-                          int n = write(1, buffer, nbytesread);
+                          ssize_t n = nsh_write(vtbl, buffer, nbytesread);
                           if (n < 0)
                             {
                               /* EINTR is not an error (but will stop stop the cat) */

examples/nsh/nsh_serial.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * examples/nsh/nsh_serial.c
  *
- *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -45,6 +45,8 @@
 #include <unistd.h>
 #include <string.h>
 #include <stdarg.h>
+#include <errno.h>
+#include <debug.h>
 
 #include "nsh.h"
 
@@ -78,6 +80,7 @@ struct serialsave_s
 static FAR struct nsh_vtbl_s *nsh_consoleclone(FAR struct nsh_vtbl_s *vtbl);
 static void nsh_consolerelease(FAR struct nsh_vtbl_s *vtbl);
 #endif
+static ssize_t nsh_consolewrite(FAR struct nsh_vtbl_s *vtbl, FAR const void *buffer, size_t nbytes);
 static int nsh_consoleoutput(FAR struct nsh_vtbl_s *vtbl, const char *fmt, ...);
 static FAR char *nsh_consolelinebuffer(FAR struct nsh_vtbl_s *vtbl);
 static void nsh_consoleredirect(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t *save);
@@ -109,6 +112,7 @@ static inline FAR struct serial_s *nsh_allocstruct(void)
       pstate->ss_vtbl.clone      = nsh_consoleclone;
       pstate->ss_vtbl.release    = nsh_consolerelease;
 #endif
+      pstate->ss_vtbl.write      = nsh_consolewrite;
       pstate->ss_vtbl.output     = nsh_consoleoutput;
       pstate->ss_vtbl.linebuffer = nsh_consolelinebuffer;
       pstate->ss_vtbl.redirect   = nsh_consoleredirect;
@@ -170,6 +174,41 @@ static void nsh_closeifnotclosed(struct serial_s *pstate)
     }
 }
 
+/****************************************************************************
+ * Name: nsh_consolewrite
+ *
+ * Description:
+ *   write a buffer to the remote shell window.
+ *
+ *   Currently only used by cat.
+ *
+ ****************************************************************************/
+
+static ssize_t nsh_consolewrite(FAR struct nsh_vtbl_s *vtbl, FAR const void *buffer, size_t nbytes)
+{
+  FAR struct serial_s *pstate = (FAR struct serial_s *)vtbl;
+  ssize_t 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
+   * actual open will then occur with the first output from the new task.
+   */
+
+  if (nsh_openifnotopen(pstate) != 0)
+   {
+     return (ssize_t)ERROR;
+   }
+
+  /* Write the data to the output stream */
+
+  ret = fwrite(buffer, 1, nbytes, pstate->ss_stream);
+  if (ret < 0)
+    {
+      dbg("[%d] Failed to send buffer: %d\n", pstate->ss_fd, errno);
+    }
+  return ret;
+}
+
 /****************************************************************************
  * Name: nsh_consoleoutput
  *
@@ -265,7 +304,29 @@ static void nsh_consolerelease(FAR struct nsh_vtbl_s *vtbl)
  * Name: nsh_consoleredirect
  *
  * Description:
- *   Set up for redirected output
+ *   Set up for redirected output.  This function is called from nsh_parse()
+ *   in two different contexts:
+ *
+ *   1) Redirected background commands of the form:  command > xyz.text &
+ *
+ *      In this case:
+ *      - vtbl: A newly allocated and initialized instance created by
+ *        nsh_consoleclone,
+ *      - fd:- The file descriptor of the redirected output
+ *      - save: NULL
+ *
+ *      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:
+ *      - vtbl: The current state structure,
+ *      - fd: The file descriptor of the redirected output
+ *      - save: Where to save the re-directed registers.
+ *
+ *      nsh_consoleundirect() will perform the clean-up after the redirected
+ *      command completes.
  *
  ****************************************************************************/
 
@@ -274,18 +335,39 @@ static void nsh_consoleredirect(FAR struct nsh_vtbl_s *vtbl, int fd, FAR uint8_t
   FAR struct serial_s     *pstate = (FAR struct serial_s *)vtbl;
   FAR struct serialsave_s *ssave  = (FAR struct serialsave_s *)save;
 
-  (void)nsh_openifnotopen(pstate);
+  /* Case 1: Redirected foreground commands */
-  fflush(pstate->ss_stream);
+
   if (ssave)
     {
+      /* pstate->ss_stream and ss_fd refer refer to the
+       * currently opened output stream.  If the console is open, flush
+       * any pending output.
+       */
+
+      if (pstate->ss_stream)
+        {
+          fflush(pstate->ss_stream);          
+        }
+
+      /* Save the current fd and stream values.  These will be restored
+       * when nsh_consoleundirect() is called.
+       */
+
       ssave->ss_fd     = pstate->ss_fd;
       ssave->ss_stream = pstate->ss_stream;
     }
   else
     {
-      fclose(pstate->ss_stream);
+      /* nsh_consoleclone() set pstate->ss_fd and ss_stream to refer
+       * to standard out.  We just want to leave these alone and overwrite
+       * them with the fd for the re-directed stream.
+       */
     }
 
+  /* In either case, set the fd of the new, re-directed output and nullify
+   * the output stream (it will be fdopen'ed if it is used).
+   */
+
   pstate->ss_fd     = fd;
   pstate->ss_stream = NULL;
 }

examples/nsh/nsh_telnetd.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * examples/nsh/nsh_telnetd.c
  *
- *   Copyright (C) 2007-2010 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * This is a leverage of similar logic from uIP:
@@ -147,6 +147,7 @@ static void tio_semtake(struct telnetio_s *tio);
 static FAR struct nsh_vtbl_s *nsh_telnetclone(FAR struct nsh_vtbl_s *vtbl);
 #endif
 static void nsh_telnetrelease(FAR struct nsh_vtbl_s *vtbl);
+static ssize_t nsh_telnetwrite(FAR struct nsh_vtbl_s *vtbl, FAR const void *buffer, size_t nbytes);
 static int nsh_telnetoutput(FAR struct nsh_vtbl_s *vtbl, const char *fmt, ...);
 static int nsh_redirectoutput(FAR struct nsh_vtbl_s *vtbl, const char *fmt, ...);
 static FAR char *nsh_telnetlinebuffer(FAR struct nsh_vtbl_s *vtbl);
@@ -195,6 +196,7 @@ static FAR struct telnetd_s *nsh_allocstruct(void)
       pstate->tn_vtbl.clone      = nsh_telnetclone;
       pstate->tn_vtbl.release    = nsh_telnetrelease;
 #endif
+      pstate->tn_vtbl.write      = nsh_telnetwrite;
       pstate->tn_vtbl.output     = nsh_telnetoutput;
       pstate->tn_vtbl.linebuffer = nsh_telnetlinebuffer;
       pstate->tn_vtbl.redirect   = nsh_telnetredirect;
@@ -537,6 +539,41 @@ static void *nsh_connection(void *arg)
   return NULL;
 }
 
+/****************************************************************************
+ * Name: nsh_telnetwrite
+ *
+ * Description:
+ *   write a buffer to the remote shell window.
+ *
+ *   Currently only used by cat.
+ *
+ ****************************************************************************/
+
+static ssize_t nsh_telnetwrite(FAR struct nsh_vtbl_s *vtbl, FAR const void *buffer, size_t nbytes)
+{
+  struct telnetd_s  *pstate = (struct telnetd_s *)vtbl;
+  struct telnetio_s *tio    = pstate->u.tn;
+  ssize_t            ret    = nbytes;
+
+  /* Flush anything already in the output buffer */
+
+  nsh_flush(pstate);
+
+  /* Then write the user buffer */
+
+  nsh_telnetdump(&pstate->tn_vtbl, "Buffer output",(uint8_t*)buffer, nbytes);
+
+  tio_semtake(tio); /* Only one call to send at a time */
+  ret = send(tio->tio_sockfd, buffer, nbytes, 0);
+  if (ret < 0)
+    {
+      dbg("[%d] Failed to send buffer: %d\n", tio->tio_sockfd, errno);
+    }
+
+  tio_semgive(tio);
+  return ret;
+}
+
 /****************************************************************************
  * Name: nsh_telnetoutput
  *
@@ -704,7 +741,29 @@ static void nsh_telnetrelease(FAR struct nsh_vtbl_s *vtbl)
  * Name: nsh_telnetredirect
  *
  * Description:
- *   Set up for redirected output
+ *   Set up for redirected output.  This function is called from nsh_parse()
+ *   in two different contexts:
+ *
+ *   1) Redirected background commands of the form:  command > xyz.text &
+ *
+ *      In this case:
+ *      - vtbl: A newly allocated and initialized instance created by
+ *        nsh_telnetclone,
+ *      - fd:- The file descriptor of the redirected output
+ *      - save: NULL
+ *
+ *      nsh_telnetrelease() will perform the clean-up when the clone is
+ *      destroyed.
+ *        
+ *   2) Redirected foreground commands of the form:  command > xyz.txt
+ *
+ *      In this case:
+ *      - vtbl: The current state structure,
+ *      - fd: The file descriptor of the redirected output
+ *      - save: Where to save the re-directed registers.
+ *
+ *      nsh_telnetundirect() will perform the clean-up after the redirected
+ *      command completes.
  *
  ****************************************************************************/