Fix a readline bug. If a NUL is received, it would return end-of-file

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5633 42af7a65-404d-4744-a932-0658087f49c3

8 files changed, 37 insertions, 30 deletions

diff --git a/apps/ChangeLog.txt b/apps/ChangeLog.txt
index 5b61a1277..a22d2184a 100644
--- a/apps/ChangeLog.txt
+++ b/apps/ChangeLog.txt
@@ -517,3 +517,8 @@
 	  match NuttX name change.
 	* apps/examples/ostest/restart.c:  Add a test case to verify
 	  task_restart().
+	* apps/system/readline.c:  readline() now returns EOF on any failure
+	  (instead of a negated errno value).  This is because the underlying
+	  read is based on logic similar to getc.  The value zero was being
+	  confused with a NUL.  So if a NUL was received, the NSH session
+	  would terminate because it thought it was the end of file.
diff --git a/apps/examples/cdcacm/Kconfig b/apps/examples/cdcacm/Kconfig
index 1e0b3f3ed..78fea4d0d 100644
--- a/apps/examples/cdcacm/Kconfig
+++ b/apps/examples/cdcacm/Kconfig
@@ -6,6 +6,7 @@
 config EXAMPLES_CDCACM
 	bool "CDC/ACM example"
 	default n
+	depends on CDCACM
 	---help---
 		Enable the USB CDC/ACM class driver example
 
diff --git a/apps/examples/ftpc/ftpc_main.c b/apps/examples/ftpc/ftpc_main.c
index 866a69cdb..deba62c1c 100644
--- a/apps/examples/ftpc/ftpc_main.c
+++ b/apps/examples/ftpc/ftpc_main.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * examples/ftpc/ftpc_main.c
  *
- *   Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2011-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -431,14 +431,13 @@ int ftpc_main(int argc, char **argv, char **envp)
       ret = readline(g_line, CONFIG_FTPC_LINELEN, stdin, stdout);
 
       /* Readline normally returns the number of characters read,
-       * but will return 0 on end of file or a negative value
-       * if an error occurs.  Either will cause the session to
-       * terminate.
+       * but will return EOF on end of file or if an error occurs.
+       * Either will cause the session to terminate.
        */
 
-      if (ret <= 0)
+      if (ret == EOF)
         {
-          printf("ERROR: readline failed: %d\n", ret);
+          printf("ERROR: readline failed: %d\n", errno);
           return 1;
         }
 #endif
diff --git a/apps/examples/usbterm/usbterm_main.c b/apps/examples/usbterm/usbterm_main.c
index 69301dfcd..747a52978 100644
--- a/apps/examples/usbterm/usbterm_main.c
+++ b/apps/examples/usbterm/usbterm_main.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * examples/usbterm/usbterm_main.c
  *
- *   Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2011-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -325,12 +325,11 @@ int usbterm_main(int argc, char *argv[])
       ret = readline(g_usbterm.outbuffer, CONFIG_EXAMPLES_USBTERM_BUFLEN, stdin, stdout);
 
       /* Readline normally returns the number of characters read,
-       * but will return 0 on end of file or a negative value
-       * if an error occurs.  Either will cause the session to
-       * terminate.
+       * but will return EOF on end of file or if an error occurs.  Either
+       * will cause the session to terminate.
        */
 
-      if (ret <= 0)
+      if (ret == EOF)
         {
           printf("ERROR: readline failed: %d\n", ret);
           return 1;
diff --git a/apps/include/readline.h b/apps/include/readline.h
index 647778210..6da6f3fd7 100644
--- a/apps/include/readline.h
+++ b/apps/include/readline.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/include/readline.h
  *
- *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2011, 2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -85,8 +85,8 @@ extern "C" {
  *
  * Returned values:
  *   On success, the (positive) number of bytes transferred is returned.
- *   A length of zero would indicated an end of file condition. An failure,
- *   a negated errno value is returned.
+ *   EOF is returned to indicate either an end of file condition or a
+ *   failure.
  *
  **************************************************************************/
 
diff --git a/apps/nshlib/nsh_consolemain.c b/apps/nshlib/nsh_consolemain.c
index 8be44f7aa..27e9d6db9 100644
--- a/apps/nshlib/nsh_consolemain.c
+++ b/apps/nshlib/nsh_consolemain.c
@@ -42,8 +42,6 @@
 #include <stdio.h>
 #include <assert.h>
 
-#include <apps/readline.h>
-
 #include "nsh.h"
 #include "nsh_console.h"
 
diff --git a/apps/nshlib/nsh_session.c b/apps/nshlib/nsh_session.c
index 8079b2de5..0c5249672 100644
--- a/apps/nshlib/nsh_session.c
+++ b/apps/nshlib/nsh_session.c
@@ -129,11 +129,13 @@ int nsh_session(FAR struct console_stdio_s *pstate)
       fputs(g_nshprompt, pstate->cn_outstream);
       fflush(pstate->cn_outstream);
 
-      /* Get the next line of input */
+      /* Get the next line of input. readline() returns EOF on end-of-file
+       * or any read failure.
+       */
 
       ret = readline(pstate->cn_line, CONFIG_NSH_LINELEN,
                      INSTREAM(pstate), OUTSTREAM(pstate));
-      if (ret > 0)
+      if (ret != EOF)
         {
           /* Parse process the command */
 
@@ -142,9 +144,8 @@ int nsh_session(FAR struct console_stdio_s *pstate)
         }
 
       /* Readline normally returns the number of characters read,
-       * but will return 0 on end of file or a negative value
-       * if an error occurs.  Either will cause the session to
-       * terminate.
+       * but will return EOF on end of file or if an error occurs.
+       * EOF will cause the session to terminate.
        */
 
       else
diff --git a/apps/system/readline/readline.c b/apps/system/readline/readline.c
index bac7eee8c..1fb30e840 100644
--- a/apps/system/readline/readline.c
+++ b/apps/system/readline/readline.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/system/readline/readline.c
  *
- *   Copyright (C) 2007-2008, 2011-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2008, 2011-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -136,9 +136,9 @@ static inline int readline_rawgetc(int infd)
  
       if (nread == 0)
         {
-          /* Return zero on end-of-file */
+          /* Return EOF on end-of-file */
 
-          return 0;
+          return EOF;
         }
 
       /* Check if an error occurred */
@@ -152,7 +152,9 @@ static inline int readline_rawgetc(int infd)
           int errcode = errno;
           if (errcode != EINTR)
             {
-              return -errcode;
+              /* Return EOF on any errors that we cannot handle */
+
+              return EOF;
             }
         }
     }
@@ -233,8 +235,8 @@ static inline void readline_consolewrite(int outfd, FAR const char *buffer, size
  *
  * Returned values:
  *   On success, the (positive) number of bytes transferred is returned.
- *   A length of zero would indicate an end of file condition. On failure,
- *   a negated errno value is returned.
+ *   EOF is returned to indicate either an end of file condition or a
+ *   failure.
  *
  **************************************************************************/
 
@@ -281,13 +283,15 @@ ssize_t readline(FAR char *buf, int buflen, FILE *instream, FILE *outstream)
 
   for(;;)
     {
-      /* Get the next character */
+      /* Get the next character. readline_rawgetc() returns EOF on any
+       * errors or at the end of file.
+       */
 
       int ch = readline_rawgetc(infd);
 
       /* Check for end-of-file or read error */
 
-      if (ch <= 0)
+      if (ch == EOF)
         {
           /* Did we already received some data? */
 
@@ -302,7 +306,7 @@ ssize_t readline(FAR char *buf, int buflen, FILE *instream, FILE *outstream)
               return nch;
             }
 
-          return ch;
+          return EOF;
         }
 
       /* Are we processing a VT100 escape sequence */