/****************************************************************************
* apps/nshlib/nsh_fileapps.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 <spawn.h>
#include <errno.h>
#include <string.h>
#include "nsh.h"
#include "nsh_console.h"
#ifdef CONFIG_NSH_FILE_APPS
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nsh_fileapp
*
* Description:
* Attempt to execute the application task whose name is 'cmd'
*
* Returned Value:
* <0 If posix_spawn() 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_fileapp(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd,
FAR char **argv, FAR const char *redirfile, int oflags)
{
posix_spawn_file_actions_t file_actions;
posix_spawnattr_t attr;
pid_t pid;
int rc = 0;
int ret;
/* Initialize the attributes file actions structure */
ret = posix_spawn_file_actions_init(&file_actions);
if (ret != 0)
{
/* posix_spawn_file_actions_init returns a positive errno value on
* failure.
*/
nsh_error(vtbl, g_fmtcmdfailed, cmd, "posix_spawn_file_actions_init",
NSH_ERRNO_OF(ret));
goto errout;
}
ret = posix_spawnattr_init(&attr);
if (ret != 0)
{
/* posix_spawnattr_init returns a positive errno value on failure. */
nsh_error(vtbl, g_fmtcmdfailed, cmd, "posix_spawnattr_init",
NSH_ERRNO);
goto errout_with_actions;
}
/* Handle re-direction of output */
if (redirfile)
{
ret = posix_spawn_file_actions_addopen(&file_actions, 1, redirfile,
oflags, 0644);
if (ret != 0)
{
/* posix_spawn_file_actions_addopen returns a positive errno
* value on failure.
*/
nsh_error(vtbl, g_fmtcmdfailed, cmd,
"posix_spawn_file_actions_addopen",
NSH_ERRNO);
goto errout_with_attrs;
}
}
/* Lock the scheduler in an attempt to prevent the application from
* running until waitpid() has been called.
*/
sched_lock();
/* Execute the program. posix_spawnp returns a positive errno value on
* failure.
*/
ret = posix_spawnp(&pid, cmd, &file_actions, &attr, &argv[1], NULL);
if (ret == OK)
{
/* 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 */
{
/* Setup up to receive SIGINT if control-C entered. The return
* value is ignored because this console device may not support
* SIGINT.
*/
ioctl(stdout->fs_fd, TIOCSCTTY, pid);
/* 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.
*
* NOTE: WUNTRACED does nothing in the default case, but in the
* case the where CONFIG_SIG_SIGSTOP_ACTION=y, the file app
* may also be stopped. In that case WUNTRACED will force
* waitpid() to return with ECHILD.
*/
ret = waitpid(pid, &rc, WUNTRACED);
if (ret < 0)
{
/* If the child thread doesn't 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
{
/* Ignore the returned child pid */
ret = OK;
/* 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.
*/
}
ioctl(stdout->fs_fd, TIOCSCTTY, -1);
}
# 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)
{
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();
/* Free attributes and file actions. Ignoring return values in the case
* of an error.
*/
errout_with_actions:
posix_spawn_file_actions_destroy(&file_actions);
errout_with_attrs:
posix_spawnattr_destroy(&attr);
errout:
/* Most posix_spawn interfaces return a positive errno value on failure
* and do not set the errno variable.
*/
if (ret > 0)
{
/* Set the errno value and return -1 */
errno = ret;
ret = ERROR;
}
else if (ret < 0)
{
/* Return -1 on failure. errno should have been set. */
ret = ERROR;
}
else if (rc != 0)
{
/* 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 = 1;
}
return ret;
}
#endif /* CONFIG_NSH_FILE_APPS */