nuttx/sched/environ/env_foreach.c

/****************************************************************************
 * 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 */