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/*
* Instantiate a private user environment for the calling thread.
*
* Submitted by: fernando.ruiz@ctv.es (correo@fernando-ruiz.com)
*
* COPYRIGHT (c) 1989-2010.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h> /* free */
#include <rtems.h>
#include <rtems/chain.h>
#include <rtems/libio_.h>
/* cleanup a user environment
* NOTE: this must be called with
* thread dispatching disabled!
*/
static void
free_user_env(void *venv)
{
rtems_user_env_t *env = (rtems_user_env_t*) venv ;
if (env != &rtems_global_user_env
#ifdef HAVE_USERENV_REFCNT
&& --env->refcnt <= 0
#endif
) {
rtems_filesystem_freenode( &env->current_directory);
rtems_filesystem_freenode( &env->root_directory);
free(env);
}
}
rtems_status_code rtems_libio_set_private_env(void)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
rtems_id task_id = rtems_task_self();
rtems_filesystem_location_info_t root_loc;
rtems_filesystem_location_info_t current_loc;
rtems_user_env_t *new_env = NULL;
int rv = 0;
rv = rtems_filesystem_evaluate_path("/", 1, 0, &root_loc, 0);
if (rv != 0)
goto error_0;
rv = rtems_filesystem_evaluate_path("/", 1, 0, ¤t_loc, 0);
if (rv != 0)
goto error_1;
/*
* Malloc is necessary whenever the current task does not
* have its own environment in place. This could be:
* a) it never had one
* OR
* b) it shared another task's environment
*/
/*
* Bharath: I'm not sure if the check can be reduced to
* if( rtems_current_user_env->task_id != task_id ) {
*/
if (
rtems_current_user_env == &rtems_global_user_env
|| rtems_current_user_env->task_id != task_id
) {
new_env = malloc(sizeof(rtems_user_env_t));
if (new_env == NULL)
goto error_2;
#ifdef HAVE_USERENV_REFCNT
new_env->refcnt = 1;
#endif
sc = rtems_task_variable_add(
RTEMS_SELF,
(void*)&rtems_current_user_env,
(void(*)(void *))free_user_env
);
if (sc != RTEMS_SUCCESSFUL)
goto error_3;
rtems_current_user_env = new_env;
}
/* Inherit the global values */
*rtems_current_user_env = rtems_global_user_env;
rtems_current_user_env->task_id = task_id;
/*
* Clone the pathlocs. In contrast to most other code we must _not_ free the
* original locs because what we are trying to do here is forking off clones.
* The reason is a pathloc can be allocated by the file system and needs to
* be freed when deleting the environment.
*/
rtems_filesystem_root = root_loc;
rtems_filesystem_current = current_loc;
return RTEMS_SUCCESSFUL;
error_3:
free(new_env);
error_2:
rtems_filesystem_freenode(¤t_loc);
error_1:
rtems_filesystem_freenode(&root_loc);
error_0:
return RTEMS_NO_MEMORY;
}
/*
* Share the same private environment between two tasks:
* Task_id (remote) and RTEMS_SELF(current).
*/
/* NOTE:
*
* THIS CODE HAS NO PROTECTION IMPLEMENTED
*
* Tasks who wish to share their environments must
*
* a) assert that no participants are concurrently
* executing
* libio_share_private_env() and/or libio_set_private_env()
*
* b) mutex access to rtems_filesystem_current, rtems_filesytem_root
* while changing any of those (chdir(), chroot()).
*/
rtems_status_code rtems_libio_share_private_env(rtems_id task_id)
{
rtems_status_code sc;
rtems_user_env_t * shared_user_env;
rtems_id current_task_id;
/*
* get current task id
*/
current_task_id = rtems_task_self();
/*
* If this was an attempt to share the task with self,
* if somebody wanted to do it... Lets tell them, its shared
*/
if( task_id == current_task_id )
return RTEMS_SUCCESSFUL;
/*
* Try to get the requested user environment
*/
sc = rtems_task_variable_get(
task_id,
(void*)&rtems_current_user_env,
(void*)&shared_user_env );
/*
* If it was not successful, return the error code
*/
if (sc != RTEMS_SUCCESSFUL)
return sc;
/*
* If we are here, we have the required environment to be
* shared with the current task
*/
/*
* If we have a current environment in place, we need to
* free it, since we will be sharing the variable with the
* shared_user_env
*/
if (rtems_current_user_env->task_id==current_task_id) {
rtems_user_env_t *tmp = rtems_current_user_env;
free_user_env( tmp );
}
/* the current_user_env is the same pointer that remote env */
rtems_current_user_env = shared_user_env;
/* increase the reference count */
#ifdef HAVE_USERENV_REFCNT
rtems_current_user_env->refcnt++;
#endif
return RTEMS_SUCCESSFUL;
}
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