/****************************************************************************
* apps/nshlib/nsh_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>
#ifdef CONFIG_SCHED_WAITPID
# include <sys/ioctl.h>
# include <sys/wait.h>
#endif
#include <stdbool.h>
#include <errno.h>
#include <sched.h>
#include <signal.h>
#include <string.h>
#include <nuttx/lib/builtin.h>
#include "builtin/builtin.h"
#include "nsh.h"
#include "nsh_console.h"
#ifdef CONFIG_NSH_BUILTIN_APPS
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nsh_builtin
*
* Description:
* Attempt to execute the application task whose name is 'cmd'
*
* Returned Value:
* <0 If exec_builtin() fails, then the negated errno value
* is returned.
* -1 (ERROR) if the application task corresponding to 'cmd' could not
* be started (possibly because it doesn not exist).
* 0 (OK) if the application task corresponding to 'cmd' was
* and successfully started. If CONFIG_SCHED_WAITPID is
* defined, this return value also indicates that the
* application returned successful status (EXIT_SUCCESS)
* 1 If CONFIG_SCHED_WAITPID is defined, then this return value
* indicates that the application task was spawned successfully
* but returned failure exit status.
*
****************************************************************************/
int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
FAR char **argv, FAR const char *redirfile, int oflags)
{
#if !defined(CONFIG_NSH_DISABLEBG) && defined(CONFIG_SCHED_CHILD_STATUS)
struct sigaction act;
struct sigaction old;
#endif
int ret = OK;
/* Lock the scheduler in an attempt to prevent the application from
* running until waitpid() has been called.
*/
sched_lock();
#if !defined(CONFIG_NSH_DISABLEBG) && defined(CONFIG_SCHED_CHILD_STATUS)
/* Ignore the child status if run the application on background. */
if (vtbl->np.np_bg == true)
{
act.sa_handler = SIG_DFL;
act.sa_flags = SA_NOCLDWAIT;
sigemptyset(&act.sa_mask);
sigaction(SIGCHLD, &act, &old);
}
#endif /* CONFIG_NSH_DISABLEBG */
/* Try to find and execute the command within the list of builtin
* applications.
*/
ret = exec_builtin(cmd, argv, redirfile, oflags);
if (ret >= 0)
{
/* The application was successfully started with pre-emption disabled.
* In the simplest cases, the application will not have run because the
* the scheduler is locked. But in the case where I/O was redirected,
* a proxy task ran and broke our lock. As result, the application may
* have aso ran if its priority was higher than than the priority of
* this thread.
*
* If the application did not run to completion and if the application
* was not backgrounded, then we need to wait here for the application
* to exit. This only works works with the following options:
*
* - CONFIG_NSH_DISABLEBG - Do not run commands in background
* - CONFIG_SCHED_WAITPID - Required to run external commands in
* foreground
*/
#ifdef CONFIG_SCHED_WAITPID
/* CONFIG_SCHED_WAITPID is selected, so we may run the command in
* foreground unless we were specifically requested to run the command
* in background (and running commands in background is enabled).
*/
# ifndef CONFIG_NSH_DISABLEBG
if (vtbl->np.np_bg == false)
# endif /* CONFIG_NSH_DISABLEBG */
{
int rc = 0;
int tc = 0;
if (vtbl->isctty)
{
/* Setup up to receive SIGINT if control-C entered. */
tc = nsh_ioctl(vtbl, TIOCSCTTY, ret);
}
/* Wait for the application to exit. We did lock the scheduler
* above, but that does not guarantee that the application did not
* already run to completion in the case where I/O was redirected.
* Here the scheduler will be unlocked while waitpid is waiting
* and if the application has not yet run, it will now be able to
* do so.
*
* Also, if CONFIG_SCHED_HAVE_PARENT is defined waitpid() might
* fail even if task is still active: If the I/O was re-directed
* by a proxy task, then the ask is a child of the proxy, and not
* this task. waitpid() fails with ECHILD in either case.
*
* NOTE: WUNTRACED does nothing in the default case, but in the
* case the where CONFIG_SIG_SIGSTOP_ACTION=y, the built-in app
* may also be stopped. In that case WUNTRACED will force
* waitpid() to return with ECHILD.
*/
ret = waitpid(ret, &rc, WUNTRACED);
if (ret < 0)
{
/* If the child thread does not exist, waitpid() will return
* the error ECHLD. Since we know that the task was
* successfully started, this must be one of the cases
* described above; we have to assume that the task already
* exit'ed. In this case, we have no idea if the application
* ran successfully or not (because NuttX does not retain exit
* status of child tasks). Let's assume that is did run
* successfully.
*/
int errcode = errno;
if (errcode == ECHILD)
{
ret = OK;
}
else
{
nsh_error(vtbl, g_fmtcmdfailed, cmd, "waitpid",
NSH_ERRNO_OF(errcode));
}
}
/* Waitpid completed the wait successfully */
else
{
/* We can't return the exact status (nsh has nowhere to put it)
* so just pass back zero/nonzero in a fashion that doesn't
* look like an error.
*/
ret = (rc == 0) ? OK : 1;
/* TODO: Set the environment variable '?' to a string
* corresponding to WEXITSTATUS(rc) so that $? will expand to
* the exit status of the most recently executed task.
*/
}
if (vtbl->isctty && tc == 0)
{
nsh_ioctl(vtbl, TIOCNOTTY, 0);
}
}
# ifndef CONFIG_NSH_DISABLEBG
else
# endif /* CONFIG_NSH_DISABLEBG */
#endif /* CONFIG_SCHED_WAITPID */
/* We get here if either:
*
* - CONFIG_SCHED_WAITPID is not selected meaning that all commands
* have to be run in background, or
* - CONFIG_SCHED_WAITPID and CONFIG_NSH_DISABLEBG are both selected,
* but the user requested to run the command in background.
*
* NOTE that the case of a) CONFIG_SCHED_WAITPID is not selected and
* b) CONFIG_NSH_DISABLEBG selected cannot be supported. In that
* event, all commands will have to run in background. The waitpid()
* API must be available to support running the command in foreground.
*/
#if !defined(CONFIG_SCHED_WAITPID) || !defined(CONFIG_NSH_DISABLEBG)
{
#if !defined(CONFIG_NSH_DISABLEBG) && defined(CONFIG_SCHED_CHILD_STATUS)
/* Restore the old actions */
sigaction(SIGCHLD, &old, NULL);
# endif
struct sched_param param;
sched_getparam(ret, ¶m);
nsh_output(vtbl, "%s [%d:%d]\n", cmd, ret, param.sched_priority);
/* Backgrounded commands always 'succeed' as long as we can start
* them.
*/
ret = OK;
}
#endif /* !CONFIG_SCHED_WAITPID || !CONFIG_NSH_DISABLEBG */
}
sched_unlock();
/* If exec_builtin() or waitpid() failed, then return -1 (ERROR) with the
* errno value set appropriately.
*/
if (ret < 0)
{
return ERROR;
}
return ret;
}
#endif /* CONFIG_NSH_BUILTIN_APPS */