Fix reentrancy problems for serial

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@821 42af7a65-404d-4744-a932-0658087f49c3

4 files changed, 166 insertions, 41 deletions

diff --git a/nuttx/examples/nsh/nsh.h b/nuttx/examples/nsh/nsh.h
index 0cc47274a..ff6df6b24 100644
--- a/nuttx/examples/nsh/nsh.h
+++ b/nuttx/examples/nsh/nsh.h
@@ -115,27 +115,27 @@ extern const char g_fmtcmdoutofmemory[];
 
 /* Message handler */
 
-extern int   nsh_parse(FAR void *handle, char *cmdline);
+extern int nsh_parse(FAR void *handle, char *cmdline);
 
 /* I/O interfaces */
 
-#ifdef CONFIG_EXAMPLES_NSH_TELNET
-
-extern int nsh_telnetmain(void);
-extern int nsh_telnetout(FAR void *handle, const char *fmt, ...);
-
-# define nsh_main()              nsh_telnetmain()
-# define nsh_output(handle, ...) nsh_telnetout(handle, __VA_ARGS__)
+extern int nsh_main(void);
+extern int nsh_output(FAR void *handle, const char *fmt, ...);
+extern FAR char *nsh_linebuffer(FAR void *handle);
 
+#ifndef CONFIG_EXAMPLES_NSH_TELNET /* Not yet supported on telnetd interface */
+extern FAR void *nsh_clone(FAR void *handle);
+extern void  nsh_addref(FAR void *handle);
+extern void  nsh_release(FAR void *handle);
+extern void *nsh_redirect(int fd);
+extern void  nsh_restore(void *direct);
 #else
-
-extern int nsh_serialmain(void);
-
-# define nsh_main()              nsh_serialmain()
-# define nsh_output(handle, ...) printf(__VA_ARGS__)
-
+#  define nsh_clone(handle) (handle)
+#  define nsh_addref(handle)
+#  define nsh_release(handle);
+#  define nsh_redirect(fd) (NULL);
+#  define nsh_restore(direct)
 #endif
-extern char *nsh_linebuffer(FAR void *handle);
 
 /* Shell command handlers */
 
diff --git a/nuttx/examples/nsh/nsh_main.c b/nuttx/examples/nsh/nsh_main.c
index 785062bc5..cf20141cb 100644
--- a/nuttx/examples/nsh/nsh_main.c
+++ b/nuttx/examples/nsh/nsh_main.c
@@ -256,6 +256,7 @@ static int nsh_execute(int argc, char *argv[])
      }
 
    handler(handle, argc, &argv[2]);
+   nsh_release(handle);
    return OK;
 }
 
@@ -361,16 +362,15 @@ int nsh_parse(FAR void *handle, char *cmdline)
        *             in the "background"
        * argv[1]:    This is string version of the handle needed to execute
        *             the command (under telnetd).  It is a string because
-       *             binary values cannot be provided via char *argv[]
+       *             binary values cannot be provided via char *argv[].  NOTE
+       *             that this value is filled in later.
        * argv[2]:    The command name.  This is argv[0] when the arguments
        *             are, finally, received by the command handler
        * argv[3]:    The beginning of argument (up to NSH_MAX_ARGUMENTS)
        * argv[argc]: NULL terminating pointer
        */
 
-      sprintf(strhandle, "%p\n", handle);
       argv[0] = "nsh_execute";
-      argv[1] = strhandle;
       argv[2] = cmd;
       for (argc = 3; argc < NSH_MAX_ARGUMENTS+4; argc++)
         {
@@ -400,8 +400,25 @@ int nsh_parse(FAR void *handle, char *cmdline)
         {
           struct sched_param param;
           int priority;
+          void *bkghandle;
 
-          /* Get the execution priority of this task */
+          /* Get a cloned copy of the handle with reference count=1.
+           * after the command has been processed, the nsh_release() call
+           * at the end of nsh_execute() will destroy the clone.
+           */
+
+          bkghandle = nsh_clone(handle);
+
+          /* Place a string copy of the cloned handle in the argument list */
+
+          sprintf(strhandle, "%p\n", bkghandle);
+          argv[1] = strhandle;
+
+         /* Handle redirection of output via a file descriptor */
+
+         /* (void)nsh_redirect(bkghandle); */
+
+         /* Get the execution priority of this task */
 
           ret = sched_getparam(0, &param);
           if (ret != 0)
@@ -455,17 +472,43 @@ int nsh_parse(FAR void *handle, char *cmdline)
         }
       else
         {
+          /* void *save; */
+
+          /* Increment the reference count on the handle.  This reference count will
+           * be decremented at the end of nsh_execute() and exists only for compatibility
+           * with the background command logic.
+           */
+
+          nsh_addref(handle);
+
+          /* Place a string copy of the original handle in the argument list */
+
+          sprintf(strhandle, "%p\n", handle);
+          argv[1] = strhandle;
+
+          /* Handle redirection of output via a file descriptor */
+          /* save = nsh_redirect(fd); */
+
+          /* Then execute the command in "foreground" -- i.e., while the user waits
+           * for the next prompt.
+           */
+
           ret = nsh_execute(argc, argv);
+          if (ret < 0)
+            {
+              return ERROR;
+            }
+
+          /* Restore the original output */
+
+          /* nsh_undirect(save); */
         }
 
       /* Return success if the command succeeded (or at least, starting of the
        * command task succeeded).
        */
 
-      if (ret == 0)
-        {
-          return OK;
-        }
+      return OK;
     }
 
   return ERROR;
diff --git a/nuttx/examples/nsh/nsh_serial.c b/nuttx/examples/nsh/nsh_serial.c
index 5052109d2..fee653266 100644
--- a/nuttx/examples/nsh/nsh_serial.c
+++ b/nuttx/examples/nsh/nsh_serial.c
@@ -43,6 +43,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 
 #include "nsh.h"
 
@@ -54,13 +55,10 @@
  * Private Types
  ****************************************************************************/
 
-struct cmdmap_s
+struct serial_s
 {
-  const char *cmd;        /* Name of the command */
-  cmd_t       handler;    /* Function that handles the command */
-  ubyte       minargs;    /* Minimum number of arguments (including command) */
-  ubyte       maxargs;    /* Maximum number of arguments (including command) */
-  const char *usage;      /* Usage instructions for 'help' command */
+  int         ss_refs;    /* Reference counts on the intance */
+  char        ss_line[CONFIG_EXAMPLES_NSH_LINELEN];
 };
 
 /****************************************************************************
@@ -71,8 +69,6 @@ struct cmdmap_s
  * Private Data
  ****************************************************************************/
 
-static char g_line[CONFIG_EXAMPLES_NSH_LINELEN];
-
 /****************************************************************************
  * Public Data
  ****************************************************************************/
@@ -82,6 +78,20 @@ static char g_line[CONFIG_EXAMPLES_NSH_LINELEN];
  ****************************************************************************/
 
 /****************************************************************************
+ * Name: nsh_allocstruct
+ ****************************************************************************/
+
+static inline FAR struct serial_s *nsh_allocstruct(void)
+{
+  struct serial_s *pstate = (struct serial_s *)malloc(sizeof(struct serial_s));
+  if (pstate)
+    {
+      pstate->ss_refs = 1;
+    }
+  return pstate;
+}
+
+/****************************************************************************
  * Public Functions
  ****************************************************************************/
 
@@ -89,8 +99,10 @@ static char g_line[CONFIG_EXAMPLES_NSH_LINELEN];
  * Name: nsh_main
  ****************************************************************************/
 
-int nsh_serialmain(void)
+int nsh_main(void)
 {
+  FAR struct serial_s *pstate = nsh_allocstruct();
+
   printf("NuttShell (NSH)\n");
   fflush(stdout);
 
@@ -103,17 +115,37 @@ int nsh_serialmain(void)
 
       /* Get the next line of input */
 
-      if (fgets(g_line, CONFIG_EXAMPLES_NSH_LINELEN, stdin))
+      if (fgets(pstate->ss_line, CONFIG_EXAMPLES_NSH_LINELEN, stdin))
         {
           /* Parse process the command */
 
-          (void)nsh_parse(NULL, g_line);
+          (void)nsh_parse(pstate, pstate->ss_line);
           fflush(stdout);
         }
     }
 }
 
 /****************************************************************************
+ * Name: nsh_output
+ *
+ * Description:
+ *   Print a string to stdout.
+ *
+ ****************************************************************************/
+
+int nsh_output(FAR void *handle, const char *fmt, ...)
+{
+  va_list ap;
+  int     ret;
+ 
+  va_start(ap, fmt);
+  ret = vfprintf(stdout, fmt, ap);
+  va_end(ap);
+ 
+  return ret;
+}
+
+/****************************************************************************
  * Name: nsh_linebuffer
  *
  * Description:
@@ -121,9 +153,59 @@ int nsh_serialmain(void)
  *
  ****************************************************************************/
 
-extern char *nsh_linebuffer(FAR void *handle)
+FAR char *nsh_linebuffer(FAR void *handle)
+{
+  FAR struct serial_s *pstate = (FAR struct serial_s *)handle;
+  return pstate->ss_line;
+}
+
+/****************************************************************************
+ * Name: nsh_clone
+ *
+ * Description:
+ *   Make an independent copy of the handle
+ *
+ ****************************************************************************/
+
+FAR void *nsh_clone(FAR void *handle)
 {
-  return g_line;
+  return nsh_allocstruct();
+}
+
+/****************************************************************************
+ * Name: nsh_addref
+ *
+ * Description:
+ *   Increment the reference count on the handle.
+ *
+ ****************************************************************************/
+
+void nsh_addref(FAR void *handle)
+{
+  FAR struct serial_s *pstate = (FAR struct serial_s *)handle;
+  pstate->ss_refs++;
+}
+
+/****************************************************************************
+ * Name: nsh_release
+ *
+ * Description:
+ *   Decrement the reference count on the handle, releasing it when the count
+ *   decrements to zero.
+ *
+ ****************************************************************************/
+
+void nsh_release(FAR void *handle)
+{
+  FAR struct serial_s *pstate = (FAR struct serial_s *)handle;
+  if (pstate->ss_refs > 1)
+    {
+      pstate->ss_refs--;
+    }
+  else
+    {
+      free(handle);
+    }
 }
 
 /****************************************************************************
diff --git a/nuttx/examples/nsh/nsh_telnetd.c b/nuttx/examples/nsh/nsh_telnetd.c
index 0dbf6b18b..3f1c1374d 100644
--- a/nuttx/examples/nsh/nsh_telnetd.c
+++ b/nuttx/examples/nsh/nsh_telnetd.c
@@ -401,7 +401,7 @@ static void *nsh_connection(void *arg)
  ****************************************************************************/
 
 /****************************************************************************
- * Name: nsh_telnetmain
+ * Name: nsh_main
  *
  * Description:
  *   This is the main processing thread for telnetd.  It never returns
@@ -409,7 +409,7 @@ static void *nsh_connection(void *arg)
  *
  ****************************************************************************/
 
-int nsh_telnetmain(void)
+int nsh_main(void)
 {
  struct in_addr addr;
 #if defined(CONFIG_EXAMPLES_NSH_DHCPC) || defined(CONFIG_EXAMPLES_NSH_NOMAC)
@@ -492,7 +492,7 @@ int nsh_telnetmain(void)
 }
 
 /****************************************************************************
- * Name: nsh_telnetout
+ * Name: nsh_output
  *
  * Description:
  *   Print a string to the remote shell window.
@@ -503,7 +503,7 @@ int nsh_telnetmain(void)
  *
  ****************************************************************************/
 
-int nsh_telnetout(FAR void *handle, const char *fmt, ...)
+int nsh_output(FAR void *handle, const char *fmt, ...)
 {
   struct telnetd_s *pstate = (struct telnetd_s *)handle;
   int nbytes = pstate->tn_sndlen;
@@ -558,7 +558,7 @@ int nsh_telnetout(FAR void *handle, const char *fmt, ...)
  *
  ****************************************************************************/
 
-extern char *nsh_linebuffer(FAR void *handle)
+FAR char *nsh_linebuffer(FAR void *handle)
 {
   struct telnetd_s *pstate = (struct telnetd_s *)handle;
   return pstate->tn_cmd;