incubator-nuttx/sched/task/task_posixspawn.c

254 lines
9.6 KiB
C

/****************************************************************************
* sched/task/task_posixspawn.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 <sys/wait.h>
#include <spawn.h>
#include <assert.h>
#include <debug.h>
#include <errno.h>
#include <nuttx/sched.h>
#include <nuttx/kthread.h>
#include <nuttx/binfmt/binfmt.h>
#include <nuttx/binfmt/symtab.h>
#include "sched/sched.h"
#include "group/group.h"
#include "task/spawn.h"
#include "task/task.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nxposix_spawn_exec
*
* Description:
* Execute the task from the file system.
*
* Input Parameters:
*
* pidp - Upon successful completion, this will return the task ID of the
* child task in the variable pointed to by a non-NULL 'pid' argument.|
*
* path - The 'path' argument identifies the file to execute. If
* CONFIG_LIBC_ENVPATH is defined, this may be either a relative or
* or an absolute path. Otherwise, it must be an absolute path.
*
* actions - The spawn file actions
*
* attr - If the value of the 'attr' parameter is NULL, the all default
* values for the POSIX spawn attributes will be used. Otherwise, the
* attributes will be set according to the spawn flags. The
* following spawn flags are supported:
*
* - POSIX_SPAWN_SETSCHEDPARAM: Set new tasks priority to the sched_param
* value.
* - POSIX_SPAWN_SETSCHEDULER: Set the new tasks scheduler priority to
* the sched_policy value.
*
* NOTE: POSIX_SPAWN_SETSIGMASK is handled in ps_proxy().
*
* argv - argv[] is the argument list for the new task. argv[] is an
* array of pointers to null-terminated strings. The list is terminated
* with a null pointer.
*
* Returned Value:
* This function will return zero on success. Otherwise, an error number
* will be returned as the function return value to indicate the error.
* This errno value may be that set by execv(), sched_setpolicy(), or
* sched_setparam().
*
****************************************************************************/
static int nxposix_spawn_exec(FAR pid_t *pidp, FAR const char *path,
FAR const posix_spawn_file_actions_t *actions,
FAR const posix_spawnattr_t *attr,
FAR char * const argv[],
FAR char * const envp[])
{
FAR const struct symtab_s *symtab;
int nsymbols;
int pid;
int ret = OK;
DEBUGASSERT(path);
/* Get the current symbol table selection */
exec_getsymtab(&symtab, &nsymbols);
/* Disable pre-emption so that we can modify the task parameters after
* we start the new task; the new task will not actually begin execution
* until we re-enable pre-emption.
*/
sched_lock();
/* Start the task */
pid = exec_spawn(path, argv, envp, symtab, nsymbols, actions, attr);
if (pid < 0)
{
ret = -pid;
serr("ERROR: exec failed: %d\n", ret);
goto errout;
}
/* Return the task ID to the caller */
if (pid)
{
*pidp = pid;
}
/* Now set the attributes. Note that we ignore all of the return values
* here because we have already successfully started the task. If we
* return an error value, then we would also have to stop the task.
*/
if (attr)
{
spawn_execattrs(pid, attr);
}
/* Re-enable pre-emption and return */
errout:
sched_unlock();
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: posix_spawn
*
* Description:
* The posix_spawn() and posix_spawnp() functions will create a new,
* child task, constructed from a regular executable file.
*
* Input Parameters:
*
* pid - Upon successful completion, posix_spawn() and posix_spawnp() will
* return the task ID of the child task to the parent task, in the
* variable pointed to by a non-NULL 'pid' argument. If the 'pid'
* argument is a null pointer, the process ID of the child is not
* returned to the caller.
*
* path - The 'path' argument to posix_spawn() is the absolute path that
* identifies the file to execute. The 'path' argument to posix_spawnp()
* may also be a relative path and will be used to construct a pathname
* that identifies the file to execute. In the case of a relative path,
* the path prefix for the file will be obtained by a search of the
* directories passed as the environment variable PATH.
*
* NOTE: NuttX provides only one implementation: If
* CONFIG_LIBC_ENVPATH is defined, then only posix_spawnp() behavior
* is supported; otherwise, only posix_spawn behavior is supported.
*
* file_actions - If 'file_actions' is a null pointer, then file
* descriptors open in the calling process will remain open in the
* child process (unless CONFIG_FDCLONE_STDIO is defined). If
* 'file_actions' is not NULL, then the file descriptors open in the
* child process will be those open in the calling process as modified
* by the spawn file actions object pointed to by file_actions.
*
* attr - If the value of the 'attr' parameter is NULL, the all default
* values for the POSIX spawn attributes will be used. Otherwise, the
* attributes will be set according to the spawn flags. The
* posix_spawnattr_t spawn attributes object type is defined in spawn.h.
* It will contains these attributes, not all of which are supported by
* NuttX:
*
* - POSIX_SPAWN_SETPGROUP: Setting of the new task's process group is
* not supported. NuttX does not support process groups.
* - POSIX_SPAWN_SETSCHEDPARAM: Set new tasks priority to the sched_param
* value.
* - POSIX_SPAWN_SETSCHEDULER: Set the new task's scheduler policy to
* the sched_policy value.
* - POSIX_SPAWN_RESETIDS: Resetting of the effective user ID of the
* child process is not supported. NuttX does not support effective
* user IDs.
* - POSIX_SPAWN_SETSIGMASK: Set the new task's signal mask.
* - POSIX_SPAWN_SETSIGDEF: Resetting signal default actions is not
* supported. NuttX does not support default signal actions.
*
* argv - argv[] is the argument list for the new task. argv[] is an
* array of pointers to null-terminated strings. The list is terminated
* with a null pointer.
*
* envp - envp[] is an array of character pointers to null-terminated
* strings that provide the environment for the new process image.
*
* Returned Value:
* posix_spawn() and posix_spawnp() will return zero on success.
* Otherwise, an error number will be returned as the function return
* value to indicate the error:
*
* - EINVAL: The value specified by 'file_actions' or 'attr' is invalid.
* - Any errors that might have been return if vfork() and excec[l|v]()
* had been called.
*
* Assumptions/Limitations:
* - NuttX provides only posix_spawn() or posix_spawnp() behavior
* depending upon the setting of CONFIG_LIBC_ENVPATH: If
* CONFIG_LIBC_ENVPATH is defined, then only posix_spawnp() behavior
* is supported; otherwise, only posix_spawn behavior is supported.
* - Process groups are not supported (POSIX_SPAWN_SETPGROUP).
* - Effective user IDs are not supported (POSIX_SPAWN_RESETIDS).
* - Signal default actions cannot be modified in the newly task executed
* because NuttX does not support default signal actions
* (POSIX_SPAWN_SETSIGDEF).
*
* POSIX Compatibility
* - The value of the argv[0] received by the child task is assigned by
* NuttX. For the caller of posix_spawn(), the provided argv[0] will
* correspond to argv[1] received by the new task.
*
****************************************************************************/
int posix_spawn(FAR pid_t *pid, FAR const char *path,
FAR const posix_spawn_file_actions_t *file_actions,
FAR const posix_spawnattr_t *attr,
FAR char * const argv[], FAR char * const envp[])
{
sinfo("pid=%p path=%s file_actions=%p attr=%p argv=%p\n",
pid, path, file_actions, attr, argv);
if (attr != NULL)
{
spawn_proxyattrs(attr);
}
return nxposix_spawn_exec(pid, path,
file_actions != NULL ?
*file_actions : NULL, attr, argv, envp);
}