/****************************************************************************
 * apps/builtin/exec_builtin.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <spawn.h>
#include <fcntl.h>
#include <errno.h>
#include <debug.h>

#include "builtin/builtin.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: exec_builtin
 *
 * Description:
 *   Executes builtin applications registered during 'make context' time.
 *   New application is run in a separate task context (and thread).
 *
 * Input Parameter:
 *   filename  - Name of the linked-in binary to be started.
 *   argv      - Argument list
 *   redirfile - If output is redirected, this parameter will be non-NULL
 *               and will provide the full path to the file.
 *   oflags    - If output is redirected, this parameter will provide the
 *               open flags to use.  This will support file replacement
 *               of appending to an existing file.
 *
 * Returned Value:
 *   This is an end-user function, so it follows the normal convention:
 *   Returns the PID of the exec'ed module.  On failure, it returns
 *   -1 (ERROR) and sets errno appropriately.
 *
 ****************************************************************************/

int exec_builtin(FAR const char *appname, FAR char * const *argv,
                 FAR const char *redirfile, int oflags)
{
  FAR const struct builtin_s *builtin;
  posix_spawnattr_t attr;
  posix_spawn_file_actions_t file_actions;
  struct sched_param param;
  pid_t pid;
  int index;
  int ret;

  /* Verify that an application with this name exists */

  index = builtin_isavail(appname);
  if (index < 0)
    {
      ret = ENOENT;
      goto errout_with_errno;
    }

  /* Get information about the builtin */

  builtin = builtin_for_index(index);
  if (builtin == NULL)
    {
      ret = ENOENT;
      goto errout_with_errno;
    }

  /* Initialize attributes for task_spawn(). */

  ret = posix_spawnattr_init(&attr);
  if (ret != 0)
    {
      goto errout_with_errno;
    }

  ret = posix_spawn_file_actions_init(&file_actions);
  if (ret != 0)
    {
      goto errout_with_attrs;
    }

  /* Set the correct task size and priority */

  param.sched_priority = builtin->priority;
  ret = posix_spawnattr_setschedparam(&attr, &param);
  if (ret != 0)
    {
      goto errout_with_actions;
    }

  ret = task_spawnattr_setstacksize(&attr, builtin->stacksize);
  if (ret != 0)
    {
      goto errout_with_actions;
    }

  /* If robin robin scheduling is enabled, then set the scheduling policy
   * of the new task to SCHED_RR before it has a chance to run.
   */

#if CONFIG_RR_INTERVAL > 0
  ret = posix_spawnattr_setschedpolicy(&attr, SCHED_RR);
  if (ret != 0)
    {
      goto errout_with_actions;
    }

  ret = posix_spawnattr_setflags(&attr,
                                 POSIX_SPAWN_SETSCHEDPARAM |
                                 POSIX_SPAWN_SETSCHEDULER);
  if (ret != 0)
    {
      goto errout_with_actions;
    }

#else
  ret = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSCHEDPARAM);
  if (ret != 0)
    {
      goto errout_with_actions;
    }

#endif

  /* Is output being redirected? */

  if (redirfile)
    {
      /* Set up to close open redirfile and set to stdout (1) */

      ret = posix_spawn_file_actions_addopen(&file_actions, 1,
                                             redirfile, oflags, 0644);
      if (ret != 0)
        {
          serr("ERROR: posix_spawn_file_actions_addopen failed: %d\n", ret);
          goto errout_with_actions;
        }
    }

#ifdef CONFIG_LIBC_EXECFUNCS
  /* Load and execute the application. */

  ret = posix_spawn(&pid, builtin->name, &file_actions, &attr, argv, NULL);
  if (ret != 0 && builtin->main != NULL)
#endif
    {
      /* Start the built-in */

      pid = task_spawn(builtin->name, builtin->main, &file_actions,
                       &attr, (argv) ? &argv[1] : (FAR char * const *)NULL,
                       (FAR char * const *)NULL);
      ret = pid < 0 ? -pid : 0;
    }

  if (ret != 0)
    {
      serr("ERROR: task_spawn failed: %d\n", ret);
      goto errout_with_actions;
    }

  /* Free attributes and file actions.  Ignoring return values in the case
   * of an error.
   */

  /* Return the task ID of the new task if the task was successfully
   * started.  Otherwise, ret will be ERROR (and the errno value will
   * be set appropriately).
   */

  posix_spawn_file_actions_destroy(&file_actions);
  posix_spawnattr_destroy(&attr);
  return pid;

errout_with_actions:
  posix_spawn_file_actions_destroy(&file_actions);

errout_with_attrs:
  posix_spawnattr_destroy(&attr);

errout_with_errno:
  errno = ret;
  return ERROR;
}