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rt-thread/components/lwp/lwp_session.c

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/*
* Copyright (c) 2006-2023, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2023-11-17 xqyjlj the first version
* 2023-11-29 Shell Add direct reference of sess for group
*/
#include "lwp.h"
#include "lwp_internal.h"
#include "lwp_syscall.h"
#include "terminal/terminal.h"
#define DBG_TAG "lwp.session"
#define DBG_LVL DBG_WARNING
#include <rtdbg.h>
rt_session_t lwp_session_find(pid_t sid)
{
rt_base_t level;
rt_session_t session = RT_NULL;
rt_list_t *node = RT_NULL;
struct rt_object_information *information = RT_NULL;
information = rt_object_get_information(RT_Object_Class_Session);
/* parameter check */
if ((sid < 0) || (information == RT_NULL))
{
return RT_NULL;
}
if (sid == 0)
{
sid = lwp_getpid();
}
/* enter critical */
level = rt_spin_lock_irqsave(&(information->spinlock));
/* try to find session */
rt_list_for_each(node, &(information->object_list))
{
session = (rt_session_t)rt_list_entry(node, struct rt_object, list);
if (session->sid == sid)
{
rt_spin_unlock_irqrestore(&(information->spinlock), level);
return session;
}
}
rt_spin_unlock_irqrestore(&(information->spinlock), level);
return RT_NULL;
}
rt_session_t lwp_session_create(rt_lwp_t leader)
{
rt_session_t session = RT_NULL;
/* parameter check */
if (leader == RT_NULL)
{
return RT_NULL;
}
session = rt_malloc(sizeof(struct rt_session));
if (session != RT_NULL)
{
rt_object_init(&(session->object), RT_Object_Class_Session, "session");
rt_list_init(&(session->processgroup));
rt_mutex_init(&(session->mutex), "session", RT_IPC_FLAG_PRIO);
session->leader = leader;
session->sid = leader->pid;
lwp_pgrp_update_children_info(leader->pgrp, session->sid, leader->pgid);
session->foreground_pgid = session->sid;
session->ctty = RT_NULL;
}
return session;
}
int lwp_session_delete(rt_session_t session)
{
int retry = 1;
lwp_tty_t ctty;
/* parameter check */
if (session == RT_NULL)
{
return -EINVAL;
}
/* clear children sid */
lwp_session_update_children_info(session, 0);
while (retry)
{
retry = 0;
ctty = session->ctty;
SESS_LOCK_NESTED(session);
if (session->ctty == ctty)
{
if (ctty)
{
SESS_UNLOCK(session);
/**
* Note: it's safe to release the session lock now. Even if someone
* race to acquire the tty, it's safe under protection of tty_lock()
* and the check inside
*/
tty_lock(ctty);
tty_rel_sess(ctty, session);
session->ctty = RT_NULL;
}
else
{
SESS_UNLOCK(session);
}
}
else
{
SESS_UNLOCK(session);
retry = 1;
}
}
rt_object_detach(&(session->object));
rt_mutex_detach(&(session->mutex));
rt_free(session);
return 0;
}
int lwp_session_insert(rt_session_t session, rt_processgroup_t group)
{
/* parameter check */
if (session == RT_NULL || group == RT_NULL)
{
return -EINVAL;
}
SESS_LOCK_NESTED(session);
PGRP_LOCK_NESTED(group);
group->sid = session->sid;
group->session = session;
lwp_pgrp_update_children_info(group, session->sid, group->pgid);
rt_list_insert_after(&(session->processgroup), &(group->pgrp_list_node));
PGRP_UNLOCK(group);
SESS_UNLOCK(session);
return 0;
}
int lwp_session_remove(rt_session_t session, rt_processgroup_t group)
{
rt_bool_t is_empty = RT_FALSE;
/* parameter check */
if (session == RT_NULL || group == RT_NULL)
{
return -EINVAL;
}
SESS_LOCK_NESTED(session);
PGRP_LOCK_NESTED(group);
rt_list_remove(&(group->pgrp_list_node));
/* clear children sid */
lwp_pgrp_update_children_info(group, 0, group->pgid);
group->sid = 0;
group->session = RT_NULL;
PGRP_UNLOCK(group);
is_empty = rt_list_isempty(&(session->processgroup));
SESS_UNLOCK(session);
if (is_empty)
{
lwp_session_delete(session);
return 1;
}
return 0;
}
int lwp_session_move(rt_session_t session, rt_processgroup_t group)
{
rt_session_t prev_session;
/* parameter check */
if (session == RT_NULL || group == RT_NULL)
{
return -EINVAL;
}
if (lwp_sid_get_bysession(session) == lwp_sid_get_bypgrp(group))
{
return 0;
}
SESS_LOCK(session);
prev_session = group->session;
if (prev_session)
{
SESS_LOCK(prev_session);
lwp_session_remove(prev_session, group);
SESS_UNLOCK(prev_session);
}
lwp_session_insert(session, group);
SESS_UNLOCK(session);
return 0;
}
int lwp_session_update_children_info(rt_session_t session, pid_t sid)
{
rt_list_t *node = RT_NULL;
rt_processgroup_t group = RT_NULL;
if (session == RT_NULL)
{
return -EINVAL;
}
SESS_LOCK_NESTED(session);
rt_list_for_each(node, &(session->processgroup))
{
group = (rt_processgroup_t)rt_list_entry(node, struct rt_processgroup, pgrp_list_node);
PGRP_LOCK_NESTED(group);
if (sid != -1)
{
group->sid = sid;
group->session = session;
lwp_pgrp_update_children_info(group, sid, group->pgid);
}
PGRP_UNLOCK(group);
}
SESS_UNLOCK(session);
return 0;
}
int lwp_session_set_foreground(rt_session_t session, pid_t pgid)
{
rt_processgroup_t group = RT_NULL;
rt_list_t *node = RT_NULL;
rt_bool_t is_contains = RT_FALSE;
/* parameter check */
if (session == RT_NULL || pgid <= 0)
{
return -EINVAL;
}
SESS_LOCK(session);
rt_list_for_each(node, &(session->processgroup))
{
group = (rt_processgroup_t)rt_list_entry(node, struct rt_processgroup, pgrp_list_node);
PGRP_LOCK(group);
if (group->pgid == pgid)
{
is_contains = RT_TRUE;
}
PGRP_UNLOCK(group);
}
if (is_contains)
{
session->foreground_pgid = pgid;
// TODO: maybe notify tty
}
SESS_UNLOCK(session);
return is_contains ? 0 : -EINVAL;
}
/**
* setsid() creates a new session if the calling process is not a process group leader.
* The calling process is the leader of the new session (i.e., its session ID is made the same as its process ID).
* The calling process also becomes the process group leader of a new process group in the session
* (i.e., its process group ID is made the same as its process ID).
*/
sysret_t sys_setsid(void)
{
rt_lwp_t process;
pid_t pid;
rt_processgroup_t group;
rt_session_t session;
sysret_t err = 0;
process = lwp_self();
pid = lwp_to_pid(process);
/**
* if the calling process is already a process group leader.
*/
if (lwp_pgrp_find(pid))
{
err = -EPERM;
goto exit;
}
group = lwp_pgrp_create(process);
if (group)
{
lwp_pgrp_move(group, process);
session = lwp_session_create(process);
if (session)
{
lwp_session_move(session, group);
}
else
{
lwp_pgrp_delete(group);
}
err = lwp_sid_get_bysession(session);
}
else
{
err = -ENOMEM;
}
exit:
return err;
}
/**
* getsid() returns the session ID of the process with process ID pid.
* If pid is 0, getsid() returns the session ID of the calling process.
*/
sysret_t sys_getsid(pid_t pid)
{
rt_lwp_t process, self_process;
pid_t sid;
lwp_pid_lock_take();
process = lwp_from_pid_locked(pid);
lwp_pid_lock_release();
if (process == RT_NULL)
{
return -ESRCH;
}
self_process = lwp_self();
sid = lwp_sid_get_byprocess(process);
if (sid != lwp_sid_get_byprocess(self_process))
{
/**
* A process with process ID pid exists, but it is not in the same session as the calling process,
* and the implementation considers this an error.
*
* Note: Linux does not return EPERM.
*/
return -EPERM;
}
return sid;
}
#ifdef RT_USING_FINSH
#include "finsh.h"
long list_session(void)
{
int count = 0, index;
rt_session_t *sessions;
rt_session_t session;
rt_thread_t thread;
char name[RT_NAME_MAX];
rt_kprintf("SID leader process\n");
rt_kprintf("---- ----------------\n");
count = rt_object_get_length(RT_Object_Class_Session);
if (count > 0)
{
/* get pointers */
sessions = (rt_session_t *)rt_calloc(count, sizeof(rt_session_t));
if (sessions)
{
index = rt_object_get_pointers(RT_Object_Class_Session, (rt_object_t *)sessions, count);
if (index > 0)
{
for (index = 0; index < count; index++)
{
struct rt_session se;
session = sessions[index];
SESS_LOCK(session);
rt_memcpy(&se, session, sizeof(struct rt_session));
SESS_UNLOCK(session);
if (se.leader && se.leader)
{
thread = rt_list_entry(se.leader->t_grp.prev, struct rt_thread, sibling);
rt_strncpy(name, thread->parent.name, RT_NAME_MAX);
}
else
{
rt_strncpy(name, "nil", RT_NAME_MAX);
}
rt_kprintf("%4d %-*.*s\n", se.sid, RT_NAME_MAX, RT_NAME_MAX, name);
}
}
rt_free(sessions);
}
}
return 0;
}
MSH_CMD_EXPORT(list_session, list session);
#endif
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