fs/proc and sched/environ: Add support for a procfs entry that will permit examining the environment of any task.

sched/environ/Make.defs

@@ -37,7 +37,7 @@ ifneq ($(CONFIG_DISABLE_ENVIRON),y)
 
 CSRCS += env_getenvironptr.c env_dup.c env_release.c env_findvar.c
 CSRCS += env_removevar.c env_clearenv.c env_getenv.c env_putenv.c
-CSRCS += env_setenv.c env_unsetenv.c
+CSRCS += env_setenv.c env_unsetenv.c env_foreach.c
 
 # Include environ build support
 

sched/environ/env_dup.c

@@ -64,8 +64,8 @@
  *   exact duplicate of the parent task's environment.
  *
  * Input Parameters:
- *   group The child task group to receive the newly allocated copy of the
- *        parent task groups environment structure.
+ *   group - The child task group to receive the newly allocated copy of the
+ *           parent task groups environment structure.
  *
  * Returned Value:
  *   zero on success

sched/environ/env_findvar.c

@@ -59,9 +59,11 @@ static bool env_cmpname(const char *pszname, const char *peqname)
 {
   /* Search until we find anything different in the two names */
 
-  for (; *pszname == *peqname; pszname++, peqname++);
+  for (; *pszname == *peqname; pszname++, peqname++)
+    {
+    }
 
-  /* On sucess, pszname will end with '\0' and peqname with '=' */
+  /* On success, pszname will end with '\0' and peqname with '=' */
 
   if (*pszname == '\0' && *peqname == '=')
     {
@@ -83,26 +85,26 @@ static bool env_cmpname(const char *pszname, const char *peqname)
  *   specified name.
  *
  * Input Parameters:
- *   group The task group containging environment array to be searched.
- *   pname The variable name to find
+ *   group - The task group containing environment array to be searched.
+ *   pname - The variable name to find
  *
  * Returned Value:
  *   A pointer to the name=value string in the environment
  *
  * Assumptions:
  *   - Not called from an interrupt handler
- *   - Pre-emptions is disabled by caller
+ *   - Pre-emption is disabled by caller
  *
  ****************************************************************************/
 
-FAR char *env_findvar(FAR struct task_group_s *group, const char *pname)
+FAR char *env_findvar(FAR struct task_group_s *group, FAR const char *pname)
 {
-  char *ptr;
-  char *end;
+  FAR char *ptr;
+  FAR char *end;
 
   /* Verify input parameters */
 
-  DEBUGASSERT(group && pname);
+  DEBUGASSERT(group != NULL && pname != NULL);
 
   /* Search for a name=value string with matching name */
 
@@ -117,6 +119,3 @@ FAR char *env_findvar(FAR struct task_group_s *group, const char *pname)
 }
 
 #endif /* CONFIG_DISABLE_ENVIRON */
-
-
-

sched/environ/env_foreach.c

@@ -0,0 +1,111 @@
+/****************************************************************************
+ * sched/environ/env_foreach.c
+ *
+ *   Copyright (C) 2018 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 NuttX 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 <stdbool.h>
+#include <string.h>
+#include <sched.h>
+
+#include <nuttx/environ.h>
+
+#include "environ/environ.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: env_foreach
+ *
+ * Description:
+ *   Search the provided environment structure for the variable of the
+ *   specified name.
+ *
+ * Input Parameters:
+ *   group - The task group containing environment array to be searched.
+ *   cb    - The callback function to be invoked for each environment
+ *           variable.
+ *
+ * Returned Value:
+ *   Zero if the all environment variables have been traversed.  A non-zero
+ *   value means that the callback function requested early termination by
+ *   returning a nonzero value.
+ *
+ * Assumptions:
+ *   - Not called from an interrupt handler
+ *   - Pre-emptions is disabled by caller
+ *
+ ****************************************************************************/
+
+int env_foreach(FAR struct task_group_s *group, env_foreach_t cb, FAR void *arg)
+{
+  FAR char *ptr;
+  FAR char *end;
+  int ret = OK;
+
+  /* Verify input parameters */
+
+  DEBUGASSERT(group != NULL && cb != NULL);
+
+  /* Search for a name=value string with matching name */
+
+  end = &group->tg_envp[group->tg_envsize];
+  for (ptr = group->tg_envp; ptr < end; ptr += (strlen(ptr) + 1))
+    {
+      /* Perform the callback */
+
+      ret = cb(arg, ptr);
+
+      /* Terminate the traversal early if the callback so requests by
+       * returning a non-zero value.
+       */
+
+      if (ret != 0)
+        {
+          break;
+        }
+    }
+
+  return ret;
+}
+
+#endif /* CONFIG_DISABLE_ENVIRON */

sched/environ/env_getenv.c

@@ -71,7 +71,7 @@
  *
  ****************************************************************************/
 
-FAR char *getenv(const char *name)
+FAR char *getenv(FAR const char *name)
 {
   FAR struct tcb_s *rtcb;
   FAR struct task_group_s *group;

sched/environ/env_release.c

@@ -62,8 +62,8 @@
  *   environ to NULL.
  *
  * Input Parameters:
- *   group Identifies the task group containing the environment structure
- *     to be released.
+ *   group - Identifies the task group containing the environment structure
+ *           to be released.
  *
  * Returned Value:
  *   None
@@ -75,7 +75,7 @@
 
 void env_release(FAR struct task_group_s *group)
 {
-  DEBUGASSERT(group);
+  DEBUGASSERT(group != NULL);
 
   /* Free any allocate environment strings */
 

sched/environ/env_removevar.c

@@ -57,15 +57,16 @@
  *   Remove the referenced name=value pair from the environment
  *
  * Input Parameters:
- *   group The task group with the environment containing the name=value pair
- *   pvar A pointer to the name=value pair in the restroom
+ *   group - The task group with the environment containing the name=value
+ *           pair
+ *   pvar  - A pointer to the name=value pair in the restroom
  *
  * Returned Value:
  *   Zero on success
  *
  * Assumptions:
  *   - Not called from an interrupt handler
- *   - Caller has pre-emptions disabled
+ *   - Caller has pre-emption disabled
  *   - Caller will reallocate the environment structure to the correct size
  *
  ****************************************************************************/
@@ -76,7 +77,7 @@ int env_removevar(FAR struct task_group_s *group, FAR char *pvar)
   int alloc;        /* Size of the allocated environment */
   int ret = ERROR;
 
-  DEBUGASSERT(group && pvar);
+  DEBUGASSERT(group != NULL && pvar != NULL);
 
   /* Verify that the pointer lies within the environment region */
 

sched/environ/environ.h

@@ -1,7 +1,8 @@
 /****************************************************************************
  * sched/environ/environ.h
  *
- *   Copyright (C) 2007, 2009, 2013-2014 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2009, 2013-2014, 2018 Gregory Nutt. All rights
+ *     reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,8 +49,8 @@
  ****************************************************************************/
 
 #ifdef CONFIG_DISABLE_ENVIRON
-# define env_dup(group)     (0)
-# define env_release(group) (0)
+#  define env_dup(group)     (0)
+#  define env_release(group) (0)
 #else
 
 /****************************************************************************
@@ -68,14 +69,94 @@ extern "C"
  * Public Function Prototypes
  ****************************************************************************/
 
-/* Functions used by the task/pthread creation and destruction logic */
+/****************************************************************************
+ * Name: 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.
+ *
+ * Input Parameters:
+ *   group - The child task group to receive the newly allocated copy of the
+ *           parent task groups environment structure.
+ *
+ * Returned Value:
+ *   zero on success
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler.
+ *
+ ****************************************************************************/
 
 int env_dup(FAR struct task_group_s *group);
+
+/****************************************************************************
+ * Name: env_release
+ *
+ * Description:
+ *   env_release() is called only from group_leave() when the last member of
+ *   a task group exits.  The env_release() function clears the environment
+ *   of all name-value pairs and sets the value of the external variable
+ *   environ to NULL.
+ *
+ * Input Parameters:
+ *   group - Identifies the task group containing the environment structure
+ *           to be released.
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *   Not called from an interrupt handler
+ *
+ ****************************************************************************/
+
 void env_release(FAR struct task_group_s *group);
 
-/* Functions used internally by the environment handling logic */
+/****************************************************************************
+ * Name: env_findvar
+ *
+ * Description:
+ *   Search the provided environment structure for the variable of the
+ *   specified name.
+ *
+ * Input Parameters:
+ *   group - The task group containing environment array to be searched.
+ *   pname - The variable name to find
+ *
+ * Returned Value:
+ *   A pointer to the name=value string in the environment
+ *
+ * Assumptions:
+ *   - Not called from an interrupt handler
+ *   - Pre-emption is disabled by caller
+ *
+ ****************************************************************************/
 
 FAR char *env_findvar(FAR struct task_group_s *group, FAR const char *pname);
+
+/****************************************************************************
+ * Name: env_removevar
+ *
+ * Description:
+ *   Remove the referenced name=value pair from the environment
+ *
+ * Input Parameters:
+ *   group - The task group with the environment containing the name=value
+ *           pair
+ *   pvar  - A pointer to the name=value pair in the restroom
+ *
+ * Returned Value:
+ *   Zero on success
+ *
+ * Assumptions:
+ *   - Not called from an interrupt handler
+ *   - Caller has pre-emption disabled
+ *   - Caller will reallocate the environment structure to the correct size
+ *
+ ****************************************************************************/
+
 int env_removevar(FAR struct task_group_s *group, FAR char *pvar);
 
 #undef EXTERN