Add basic tasking support for environment variables

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@291 42af7a65-404d-4744-a932-0658087f49c3

11 files changed, 755 insertions, 0 deletions

diff --git a/nuttx/sched/Makefile b/nuttx/sched/Makefile
index c007feaf4..97c59201e 100644
--- a/nuttx/sched/Makefile
+++ b/nuttx/sched/Makefile
@@ -55,6 +55,8 @@ SCHED_SRCS	= sched_setparam.c sched_getparam.c \
 		  sched_yield.c sched_rrgetinterval.c sched_foreach.c \
 		  sched_getprioritymax.c sched_getprioritymin.c \
 		  sched_lock.c sched_unlock.c sched_lockcount.c
+ENV_SRCS	= env_getenvironptr.c env_dup.c env_share.c env_release.c \
+		  env_clearenv.c
 WDOG_SRCS	= wd_initialize.c wd_create.c wd_start.c wd_cancel.c wd_delete.c \
 		  wd_gettime.c
 TIME_SRCS	= sched_processtimer.c
@@ -128,6 +130,9 @@ endif
 ifneq ($(CONFIG_DISABLE_MQUEUE),y)
 CSRCS		+= $(MQUEUE_SRCS)
 endif
+ifneq ($(CONFIG_DISABLE_ENVIRON),y)
+CSRCS		+= $(ENV_SRCS)
+endif
 COBJS		= $(CSRCS:.c=$(OBJEXT))
 
 SRCS		= $(ASRCS) $(CSRCS)
diff --git a/nuttx/sched/env_clearenv.c b/nuttx/sched/env_clearenv.c
new file mode 100644
index 000000000..1181596ea
--- /dev/null
+++ b/nuttx/sched/env_clearenv.c
@@ -0,0 +1,83 @@
+/****************************************************************************
+ * env_clearenv.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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>
+
+#ifndef CONFIG_DISABLE_ENVIRON
+
+#include <sched.h>
+#include <stdlib.h>
+#include "os_internal.h"
+#include "env_internal.h"
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  clearenv
+ *
+ * Description:
+ *   The clearenv() function clears the environment of all name-value pairs
+ *   and sets the value of the external variable environ to NULL.
+
+ * Parameters:
+ *   None
+ *
+ * Return Value:
+ *   None
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler
+ *
+ ****************************************************************************/
+
+int clearenv(void)
+{
+  return env_release((FAR _TCB*)g_readytorun.head);
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+
diff --git a/nuttx/sched/env_dup.c b/nuttx/sched/env_dup.c
new file mode 100644
index 000000000..0ee1cbc81
--- /dev/null
+++ b/nuttx/sched/env_dup.c
@@ -0,0 +1,127 @@
+/****************************************************************************
+ * env_dup.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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>
+
+#ifndef CONFIG_DISABLE_ENVIRON
+
+#include <sched.h>
+#include <string.h>
+#include <errno.h>
+#include "os_internal.h"
+#include "env_internal.h"
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  env_dup
+ *
+ * Description:
+ *   Copy the internal environment structure of a task.  This is the action
+ *   that is performed when a new task is created: The new task has a private,
+ *   exact duplicate of the parent task's environment.
+ *
+ * Parameters:
+ *   ptcb The tcb to receive the newly allocated copy of the parspecifiedent
+ *        TCB's environment structure with reference count equal to one
+ *
+ * Return Value:
+ *   zero on success
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler.
+ *
+ ****************************************************************************/
+
+int env_dup(FAR _TCB *ptcb)
+{
+  int ret = OK;
+  if (!ptcb )
+    {
+      ret = -EINVAL;
+    }
+  else
+    {
+      FAR _TCB  *parent = (FAR _TCB*)g_readytorun.head;
+      environ_t *envp   = NULL;
+
+      /* Pre-emption must be disabled throughout the following because the
+       * environment may be shared.
+       */
+
+      sched_lock();
+
+      /* Does the parent task have an environment? */
+
+      if (parent->envp)
+        {
+          /* Yes..The parent task has an environment, duplicate it */
+
+          size_t envlen =  ptcb->envp->ev_alloc;
+          envp          = (environ_t*)malloc(SIZEOF_ENVIRON_T( envlen ));
+          if (!envp)
+            {
+              ret = -ENOMEM;
+            }
+          else
+            {
+              envp->ev_crefs = 1;
+              envp->ev_alloc = envlen;
+              memcmp( envp->ev_env, ptcb->envp->ev_env, envlen );
+            }
+        }
+
+      /* Save the cloned environment in the new TCB */
+
+      ptcb->envp = envp;
+      sched_unlock();
+  }
+  return ret;
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+
diff --git a/nuttx/sched/env_dupenv.c b/nuttx/sched/env_dupenv.c
new file mode 100644
index 000000000..748af878c
--- /dev/null
+++ b/nuttx/sched/env_dupenv.c
@@ -0,0 +1,108 @@
+/****************************************************************************
+ * env_dupenv.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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>
+
+#ifndef CONFIG_DISABLE_ENVIRON
+
+#include <sched.h>
+#include <stdlib.h>
+#include "os_internal.h"
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  dupenv
+ *
+ * Description:
+ *   Copy the internal environment structure of a task.  This is the action
+ *   that is performed when a new task is created: The new task has a private,
+ *   exact duplicate of the parent task's environment.
+ *
+ * Parameters:
+ *   None
+ *
+ * Return Value:
+ *   A pointer to a newly allocated copy of the specified TCB's environment
+ *   structure with reference count equal to one.
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler.
+ *
+ ****************************************************************************/
+
+FAR environ_t *dupenv(FAR _TCB *ptcb)
+{
+   environ_t *envp = NULL;
+
+  /* Pre-emption must be disabled throughout the following because the
+   * environment may be shared.
+   */
+
+  sched_lock();
+
+  /* Does the parent task have an environment? */
+
+  if (ptcb->envp)
+    {
+      /* Yes..The parent task has an environment, duplicate it */
+
+      size_t envlen =  ptcb->envp->ev_alloc
+      envp          = (environ_t*)malloc(SIZEOF_ENVIRON_T( envlen ));
+      if (envp)
+        {
+          envp->ev_crefs = 1;
+          envp->ev_alloc = envlen;
+          memcmp( envp->ev_env, ptcb->envp->ev_env, envlen );
+        }
+    }
+  sched_unlock();
+  return envp;
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+
diff --git a/nuttx/sched/env_getenvironptr.c b/nuttx/sched/env_getenvironptr.c
new file mode 100644
index 000000000..4c01250b4
--- /dev/null
+++ b/nuttx/sched/env_getenvironptr.c
@@ -0,0 +1,92 @@
+/****************************************************************************
+ * env_getenvironptr.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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>
+
+#ifndef CONFIG_DISABLE_ENVIRON
+
+#include <sched.h>
+#include <stdlib.h>
+#include "os_internal.h"
+
+#undef get_environ_ptr
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  get_environ_ptr
+ *
+ * Description:
+ *   Return a pointer to the thread specific environ variable.
+ *
+ * Parameters:
+ *   None
+ *
+ * Return Value:
+ *   A pointer to the per-thread environ variable.
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+FAR char **get_environ_ptr( void )
+{
+  /* Return a reference to the thread-private environ in the TCB.*/
+
+  FAR _TCB *ptcb = (FAR _TCB*)g_readytorun.head;
+  if (ptcb->envp)
+    {
+      return &ptcb->envp->ev_env;
+    }
+  else
+    {
+      return NULL;
+    }
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+
diff --git a/nuttx/sched/env_internal.h b/nuttx/sched/env_internal.h
new file mode 100644
index 000000000..5961362df
--- /dev/null
+++ b/nuttx/sched/env_internal.h
@@ -0,0 +1,88 @@
+/****************************************************************************
+ * env_internal.h
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+#ifndef __ENV_INTERNAL_H
+#define __ENV_INTERNAL_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/sched.h>
+#include "os_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_DISABLE_ENVIRON
+# define env_dup(ptcb)     (0)
+# define env_share(ptcb)   (0)
+# define env_release(ptcb) (0)
+#endif
+
+/****************************************************************************
+ * Public Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+#ifndef CONFIG_DISABLE_ENVIRON
+EXTERN int env_dup(FAR _TCB *ptcb);
+EXTERN int env_share(FAR _TCB *ptcb);
+EXTERN int env_release(FAR _TCB *ptcb);
+#endif
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __ENV_INTERNAL_H */
+
diff --git a/nuttx/sched/env_release.c b/nuttx/sched/env_release.c
new file mode 100644
index 000000000..96490588e
--- /dev/null
+++ b/nuttx/sched/env_release.c
@@ -0,0 +1,122 @@
+/****************************************************************************
+ * env_clearenv.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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>
+
+#ifndef CONFIG_DISABLE_ENVIRON
+
+#include <sched.h>
+#include <errno.h>
+#include "os_internal.h"
+#include "env_internal.h"
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  env_release
+ *
+ * Description:
+ *   The env_release() function clears the environment of all name-value pairs
+ *   and sets the value of the external variable environ to NULL.
+
+ * Parameters:
+ *   ptcb Identifies the TCB containing the environment structure
+ *
+ * Return Value:
+ *   zero on success
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler
+ *
+ ****************************************************************************/
+
+int env_release(FAR _TCB *ptcb)
+{
+  int ret = OK;
+  if (!ptcb)
+    {
+      ret = -EINVAL;
+    }
+  else
+    {
+      FAR environ_t *envp;
+
+      /* Examine the environ data in the TCB.  Preemption is disabled because the
+       * the environment could be shared among threads.
+       */
+
+      sched_lock();
+      envp = ptcb->envp;
+      if (ptcb->envp)
+        {
+          /* Check the reference count on the environment structure */
+
+          if ( envp->ev_crefs <= 1)
+            {
+              /* Decrementing the reference count will destroy the environment */
+
+              sched_free( envp ); /* plain free() should be fine here */
+            }
+          else
+            {
+              /* The environment will persist after decrementing the reference
+               * count */
+
+              envp->ev_crefs--;
+            }
+
+          /* In any case, the environment is no longer accessible on this thread */
+
+          ptcb->envp = NULL;
+        }
+      sched_unlock();
+    }
+  return ret;
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+
diff --git a/nuttx/sched/env_share.c b/nuttx/sched/env_share.c
new file mode 100644
index 000000000..a1c740aa7
--- /dev/null
+++ b/nuttx/sched/env_share.c
@@ -0,0 +1,115 @@
+/****************************************************************************
+ * env_share.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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>
+
+#ifndef CONFIG_DISABLE_ENVIRON
+
+#include <sched.h>
+#include <errno.h>
+#include "os_internal.h"
+#include "env_internal.h"
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  env_share
+ *
+ * Description:
+ *   Increment the reference count on the internal environment structure of
+ *   a task.  This is the action that is performed when a new pthread is
+ *   created: The new pthread shares the environment with its parent.
+ *
+ * Parameters:
+ *   ptcb The new TCB to receive the shared environment.
+ *
+ * Return Value:
+ *   A pointer to a specified TCB's environment structure with an incremented
+ *   reference count.
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler.
+ *
+ ****************************************************************************/
+
+int env_share(FAR _TCB *ptcb)
+{
+  int ret = OK;
+  if (!ptcb)
+    {
+      ret = -EINVAL;
+    }
+  else
+    {
+      FAR _TCB *parent = (FAR _TCB*)g_readytorun.head;
+      environ_t *envp = parent->envp;
+
+      /* Pre-emption must be disabled throughout the following because the
+       * environment is shared.
+       */
+
+      sched_lock();
+
+      /* Does the parent task have an environment? */
+
+      if (envp)
+        {
+          /* Yes.. increment the reference count on the environment */
+
+          envp++;
+        }
+
+      /* Then share the environment */
+
+      ptcb->envp = envp;
+      sched_unlock();
+    }
+  return ret;
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */
+
+
+
diff --git a/nuttx/sched/pthread_create.c b/nuttx/sched/pthread_create.c
index 998867349..24768664b 100644
--- a/nuttx/sched/pthread_create.c
+++ b/nuttx/sched/pthread_create.c
@@ -49,6 +49,7 @@
 #include <nuttx/arch.h>
 #include "os_internal.h"
 #include "clock_internal.h"
+#include "env_internal.h"
 #include "pthread_internal.h"
 
 /************************************************************
@@ -273,6 +274,10 @@ int pthread_create(pthread_t *thread, pthread_attr_t *attr,
       return ERROR;
     }
 
+  /* Share the parent's envionment */
+
+  (void)env_share(ptcb);
+
   /* Allocate a detachable structure to support pthread_join logic */
 
   pjoin = (FAR join_t*)kzmalloc(sizeof(join_t));
diff --git a/nuttx/sched/sched_releasetcb.c b/nuttx/sched/sched_releasetcb.c
index 5d3c8fd90..95f533c20 100644
--- a/nuttx/sched/sched_releasetcb.c
+++ b/nuttx/sched/sched_releasetcb.c
@@ -46,6 +46,7 @@
 #include <nuttx/arch.h>
 #include "os_internal.h"
 #include "timer_internal.h"
+#include "env_internal.h"
 
 /************************************************************
  * Private Functions
@@ -150,6 +151,10 @@ int sched_releasetcb(FAR _TCB *tcb)
 
       ret = sched_releasefiles(tcb);
 
+      /* Release environment variables */
+
+      (void)env_release(tcb);
+
       /* And, finally, release the TCB itself */
 
       sched_free(tcb);
diff --git a/nuttx/sched/task_create.c b/nuttx/sched/task_create.c
index 008cc378a..ee0e86c6e 100644
--- a/nuttx/sched/task_create.c
+++ b/nuttx/sched/task_create.c
@@ -44,6 +44,7 @@
 #include <debug.h>
 #include <nuttx/arch.h>
 #include "os_internal.h"
+#include "env_internal.h"
 
 /************************************************************
  * Definitions
@@ -137,6 +138,10 @@ int task_create(const char *name, int priority,
     }
 #endif
 
+  /* Clone the parent's task environment */
+
+  (void)env_dup(tcb);
+
   /* Allocate the stack for the TCB */
 
 #ifndef CONFIG_CUSTOM_STACK