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rsoc/rt-thread/components/lwp/lwp_signal.c

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/*
* Copyright (c) 2006-2023, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2019-11-12 Jesven first version
* 2023-02-23 Shell Support sigtimedwait
* 2023-07-04 Shell Support siginfo, sigqueue
* remove lwp_signal_backup/restore() to reduce architecture codes
* update the generation, pending and delivery routines
* 2023-11-22 Shell Support for job control signal. Fixup of signal catch while
* some of the signals is blocked, but no more further dequeue is applied.
* Add itimer support
*/
#define __RT_IPC_SOURCE__
#define DBG_TAG "lwp.signal"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
#include <rthw.h>
#include <rtthread.h>
#include <string.h>
#include "lwp_internal.h"
#include "sys/signal.h"
#include "syscall_generic.h"
static lwp_siginfo_t siginfo_create(rt_thread_t current, int signo, int code, lwp_siginfo_ext_t ext)
{
lwp_siginfo_t siginfo;
struct rt_lwp *self_lwp;
rt_thread_t self_thr;
siginfo = rt_malloc(sizeof(*siginfo));
if (siginfo)
{
siginfo->ksiginfo.signo = signo;
siginfo->ksiginfo.code = code;
siginfo->ext = ext;
self_thr = current;
self_lwp = current->lwp;
if (self_lwp)
{
siginfo->ksiginfo.from_pid = self_lwp->pid;
siginfo->ksiginfo.from_tid = self_thr->tid;
}
else
{
siginfo->ksiginfo.from_pid = 0;
siginfo->ksiginfo.from_tid = 0;
}
}
return siginfo;
}
rt_inline void siginfo_delete(lwp_siginfo_t siginfo)
{
if (siginfo->ext)
{
rt_free(siginfo->ext);
siginfo->ext = RT_NULL;
}
rt_free(siginfo);
}
rt_inline void _sigorsets(lwp_sigset_t *dset, const lwp_sigset_t *set0, const lwp_sigset_t *set1)
{
switch (_LWP_NSIG_WORDS)
{
case 4:
dset->sig[3] = set0->sig[3] | set1->sig[3];
dset->sig[2] = set0->sig[2] | set1->sig[2];
case 2:
dset->sig[1] = set0->sig[1] | set1->sig[1];
case 1:
dset->sig[0] = set0->sig[0] | set1->sig[0];
default:
return;
}
}
rt_inline void _sigandsets(lwp_sigset_t *dset, const lwp_sigset_t *set0, const lwp_sigset_t *set1)
{
switch (_LWP_NSIG_WORDS)
{
case 4:
dset->sig[3] = set0->sig[3] & set1->sig[3];
dset->sig[2] = set0->sig[2] & set1->sig[2];
case 2:
dset->sig[1] = set0->sig[1] & set1->sig[1];
case 1:
dset->sig[0] = set0->sig[0] & set1->sig[0];
default:
return;
}
}
rt_inline void _signotsets(lwp_sigset_t *dset, const lwp_sigset_t *set)
{
switch (_LWP_NSIG_WORDS)
{
case 4:
dset->sig[3] = ~set->sig[3];
dset->sig[2] = ~set->sig[2];
case 2:
dset->sig[1] = ~set->sig[1];
case 1:
dset->sig[0] = ~set->sig[0];
default:
return;
}
}
rt_inline void _sigaddset(lwp_sigset_t *set, int _sig)
{
unsigned long sig = _sig - 1;
if (_LWP_NSIG_WORDS == 1)
{
set->sig[0] |= 1UL << sig;
}
else
{
set->sig[sig / _LWP_NSIG_BPW] |= 1UL << (sig % _LWP_NSIG_BPW);
}
}
rt_inline void _sigdelset(lwp_sigset_t *set, int _sig)
{
unsigned long sig = _sig - 1;
if (_LWP_NSIG_WORDS == 1)
{
set->sig[0] &= ~(1UL << sig);
}
else
{
set->sig[sig / _LWP_NSIG_BPW] &= ~(1UL << (sig % _LWP_NSIG_BPW));
}
}
rt_inline int _sigisemptyset(lwp_sigset_t *set)
{
switch (_LWP_NSIG_WORDS)
{
case 4:
return (set->sig[3] | set->sig[2] |
set->sig[1] | set->sig[0]) == 0;
case 2:
return (set->sig[1] | set->sig[0]) == 0;
case 1:
return set->sig[0] == 0;
default:
return 1;
}
}
rt_inline int _sigismember(lwp_sigset_t *set, int _sig)
{
unsigned long sig = _sig - 1;
if (_LWP_NSIG_WORDS == 1)
{
return 1 & (set->sig[0] >> sig);
}
else
{
return 1 & (set->sig[sig / _LWP_NSIG_BPW] >> (sig % _LWP_NSIG_BPW));
}
}
rt_inline int _next_signal(lwp_sigset_t *pending, lwp_sigset_t *mask)
{
unsigned long i, *s, *m, x;
int sig = 0;
s = pending->sig;
m = mask->sig;
x = *s & ~*m;
if (x)
{
sig = rt_hw_ffz(~x) + 1;
return sig;
}
switch (_LWP_NSIG_WORDS)
{
default:
for (i = 1; i < _LWP_NSIG_WORDS; ++i)
{
x = *++s &~ *++m;
if (!x)
continue;
sig = rt_hw_ffz(~x) + i*_LWP_NSIG_BPW + 1;
break;
}
break;
case 2:
x = s[1] &~ m[1];
if (!x)
break;
sig = rt_hw_ffz(~x) + _LWP_NSIG_BPW + 1;
break;
case 1:
/* Nothing to do */
break;
}
return sig;
}
#define _SIGQ(tp) (&(tp)->signal.sig_queue)
rt_inline int sigqueue_isempty(lwp_sigqueue_t sigqueue)
{
return _sigisemptyset(&sigqueue->sigset_pending);
}
rt_inline int sigqueue_ismember(lwp_sigqueue_t sigqueue, int signo)
{
return _sigismember(&sigqueue->sigset_pending, signo);
}
rt_inline int sigqueue_peek(lwp_sigqueue_t sigqueue, lwp_sigset_t *mask)
{
return _next_signal(&sigqueue->sigset_pending, mask);
}
rt_inline int sigqueue_examine(lwp_sigqueue_t sigqueue, lwp_sigset_t *pending)
{
int is_empty = sigqueue_isempty(sigqueue);
if (!is_empty)
{
_sigorsets(pending, &sigqueue->sigset_pending, &sigqueue->sigset_pending);
}
return is_empty;
}
static void sigqueue_enqueue(lwp_sigqueue_t sigqueue, lwp_siginfo_t siginfo)
{
lwp_siginfo_t idx;
rt_bool_t inserted = RT_FALSE;
rt_list_for_each_entry(idx, &sigqueue->siginfo_list, node)
{
if (idx->ksiginfo.signo >= siginfo->ksiginfo.signo)
{
rt_list_insert_after(&idx->node, &siginfo->node);
inserted = RT_TRUE;
break;
}
}
if (!inserted)
rt_list_insert_before(&sigqueue->siginfo_list, &siginfo->node);
_sigaddset(&sigqueue->sigset_pending, siginfo->ksiginfo.signo);
return ;
}
/**
* dequeue a siginfo matching the signo which is likely to be existed, and
* test if any other siblings remains
*/
static lwp_siginfo_t sigqueue_dequeue(lwp_sigqueue_t sigqueue, int signo)
{
lwp_siginfo_t found;
lwp_siginfo_t candidate;
lwp_siginfo_t next;
rt_bool_t is_empty;
found = RT_NULL;
is_empty = RT_TRUE;
rt_list_for_each_entry_safe(candidate, next, &sigqueue->siginfo_list, node)
{
if (candidate->ksiginfo.signo == signo)
{
if (found)
{
/* already found */
is_empty = RT_FALSE;
break;
}
else
{
/* found first */
found = candidate;
rt_list_remove(&found->node);
}
}
else if (candidate->ksiginfo.signo > signo)
break;
}
if (found && is_empty)
_sigdelset(&sigqueue->sigset_pending, signo);
return found;
}
/**
* Discard all the signal matching `signo` in sigqueue
*/
static void sigqueue_discard(lwp_sigqueue_t sigqueue, int signo)
{
lwp_siginfo_t queuing_si;
while (sigqueue_ismember(sigqueue, signo))
{
queuing_si = sigqueue_dequeue(sigqueue, signo);
siginfo_delete(queuing_si);
}
}
/**
* Discard all the queuing signals in sigset
*/
static void sigqueue_discard_sigset(lwp_sigqueue_t sigqueue, lwp_sigset_t *sigset)
{
lwp_siginfo_t queuing_si;
lwp_sigset_t mask;
int signo;
_signotsets(&mask, sigset);
while ((signo = sigqueue_peek(sigqueue, &mask)) != 0)
{
queuing_si = sigqueue_dequeue(sigqueue, signo);
siginfo_delete(queuing_si);
}
}
/* assuming that (void *) is compatible to long at length */
RT_STATIC_ASSERT(lp_width_same, sizeof(void *) == sizeof(long));
/** translate lwp siginfo to user siginfo_t */
rt_inline void siginfo_k2u(lwp_siginfo_t ksigi, siginfo_t *usigi)
{
int signo = ksigi->ksiginfo.signo;
usigi->si_code = ksigi->ksiginfo.code;
usigi->si_signo = signo;
usigi->si_pid = ksigi->ksiginfo.from_pid;
if (ksigi->ext)
{
if (signo == SIGCHLD)
{
usigi->si_status = ksigi->ext->sigchld.status;
usigi->si_utime = ksigi->ext->sigchld.stime;
usigi->si_stime = ksigi->ext->sigchld.utime;
}
}
/* deprecated field */
usigi->si_errno = 0;
}
/* must called in locked context */
rt_inline lwp_sighandler_t _get_sighandler_locked(struct rt_lwp *lwp, int signo)
{
return lwp->signal.sig_action[signo - 1];
}
static lwp_sigset_t *_mask_block_fn(rt_thread_t thread, const lwp_sigset_t *sigset, lwp_sigset_t *new_set)
{
_sigorsets(new_set, &thread->signal.sigset_mask, sigset);
return new_set;
}
static lwp_sigset_t *_mask_unblock_fn(rt_thread_t thread, const lwp_sigset_t *sigset, lwp_sigset_t *new_set)
{
lwp_sigset_t complement;
_signotsets(&complement, sigset);
_sigandsets(new_set, &thread->signal.sigset_mask, &complement);
return new_set;
}
static lwp_sigset_t *_mask_set_fn(rt_thread_t thread, const lwp_sigset_t *sigset, lwp_sigset_t *new_set)
{
memcpy(new_set, sigset, sizeof(*sigset));
return new_set;
}
static lwp_sigset_t *(*_sig_mask_fn[__LWP_SIG_MASK_CMD_WATERMARK])
(rt_thread_t thread, const lwp_sigset_t *sigset, lwp_sigset_t *new_set) = {
[LWP_SIG_MASK_CMD_BLOCK] = _mask_block_fn,
[LWP_SIG_MASK_CMD_UNBLOCK] = _mask_unblock_fn,
[LWP_SIG_MASK_CMD_SET_MASK] = _mask_set_fn,
};
static void _thread_signal_mask(rt_thread_t thread, lwp_sig_mask_cmd_t how,
const lwp_sigset_t *sigset, lwp_sigset_t *oset)
{
lwp_sigset_t new_set;
/**
* Note: POSIX wants this API to be capable to query the current mask
* by passing NULL in `sigset`
*/
if (oset)
memcpy(oset, &thread->signal.sigset_mask, sizeof(lwp_sigset_t));
if (sigset)
{
_sig_mask_fn[how](thread, sigset, &new_set);
/* remove un-maskable signal from set */
_sigdelset(&new_set, SIGKILL);
_sigdelset(&new_set, SIGSTOP);
memcpy(&thread->signal.sigset_mask, &new_set, sizeof(lwp_sigset_t));
}
}
void lwp_sigqueue_clear(lwp_sigqueue_t sigq)
{
lwp_siginfo_t this, next;
if (!sigqueue_isempty(sigq))
{
rt_list_for_each_entry_safe(this, next, &sigq->siginfo_list, node)
{
siginfo_delete(this);
}
}
}
static void lwp_signal_notify(rt_slist_t *list_head, lwp_siginfo_t siginfo)
{
rt_slist_t *node;
rt_slist_for_each(node, list_head)
{
struct rt_lwp_notify *n = rt_slist_entry(node, struct rt_lwp_notify, list_node);
if (n->notify)
{
n->notify(n->signalfd_queue, siginfo->ksiginfo.signo);
}
}
}
rt_err_t lwp_signal_init(struct lwp_signal *sig)
{
rt_err_t rc = RT_EOK;
sig->real_timer = LWP_SIG_INVALID_TIMER;
memset(&sig->sig_dispatch_thr, 0, sizeof(sig->sig_dispatch_thr));
memset(&sig->sig_action, 0, sizeof(sig->sig_action));
memset(&sig->sig_action_nodefer, 0, sizeof(sig->sig_action_nodefer));
memset(&sig->sig_action_onstack, 0, sizeof(sig->sig_action_onstack));
memset(&sig->sig_action_restart, 0, sizeof(sig->sig_action_restart));
memset(&sig->sig_action_siginfo, 0, sizeof(sig->sig_action_siginfo));
memset(&sig->sig_action_nocldstop, 0, sizeof(sig->sig_action_nocldstop));
memset(&sig->sig_action_nocldwait, 0, sizeof(sig->sig_action_nocldwait));
lwp_sigqueue_init(&sig->sig_queue);
return rc;
}
rt_err_t lwp_signal_detach(struct lwp_signal *signal)
{
rt_err_t ret = RT_EOK;
timer_delete(signal->real_timer);
lwp_sigqueue_clear(&signal->sig_queue);
return ret;
}
int lwp_thread_signal_suspend_check(rt_thread_t thread, int suspend_flag)
{
struct rt_lwp *lwp = (struct rt_lwp *)thread->lwp;
lwp_sigset_t sigmask = thread->signal.sigset_mask;
int ret = 0;
_sigaddset(&sigmask, SIGCONT);
switch (suspend_flag)
{
case RT_INTERRUPTIBLE:
if (sigqueue_peek(_SIGQ(thread), &sigmask))
{
break;
}
if (thread->lwp && sigqueue_peek(_SIGQ(lwp), &sigmask))
{
break;
}
ret = 1;
break;
case RT_KILLABLE:
if (sigqueue_ismember(_SIGQ(thread), SIGKILL))
{
break;
}
if (thread->lwp && sigqueue_ismember(_SIGQ(lwp), SIGKILL))
{
break;
}
ret = 1;
break;
case RT_UNINTERRUPTIBLE:
ret = 1;
break;
default:
RT_ASSERT(0);
break;
}
return ret;
}
rt_inline rt_bool_t _is_jobctl_signal(rt_lwp_t lwp, int signo)
{
lwp_sigset_t jobctl_sigset = lwp_sigset_init(LWP_SIG_JOBCTL_SET);
return lwp_sigismember(&jobctl_sigset, signo);
}
rt_inline rt_bool_t _is_stop_signal(rt_lwp_t lwp, int signo)
{
lwp_sigset_t stop_sigset = lwp_sigset_init(LWP_SIG_STOP_SET);
return lwp_sigismember(&stop_sigset, signo);
}
rt_inline rt_bool_t _need_notify_status_changed(rt_lwp_t lwp, int signo)
{
RT_ASSERT(lwp_sigismember(&lwp_sigset_init(LWP_SIG_JOBCTL_SET), signo));
return !lwp_sigismember(&lwp->signal.sig_action_nocldstop, SIGCHLD);
}
/**
* wakeup the waitpid_waiters if any, and try to generate SIGCHLD if they are
* not disable explicitly by user.
*
* TODO: This event is always per-process and doesn't make whole lot of
* sense for ptracers, who shouldn't consume the state via wait(2) either,
* but, for backward compatibility, notify the ptracer of the group leader
* too unless it's gonna be a duplicate.
*/
static void _notify_parent_and_leader(rt_lwp_t child_lwp, rt_thread_t child_thr, int trig_signo, rt_bool_t is_stop)
{
int si_code;
lwp_siginfo_ext_t ext;
rt_lwp_t parent_lwp = child_lwp->parent;
if (!parent_lwp)
return ;
/* prepare the event data for parent to query */
if (is_stop)
{
si_code = CLD_STOPPED;
child_lwp->lwp_status = LWP_CREATE_STAT_STOPPED(trig_signo);
}
else
{
si_code = CLD_CONTINUED;
child_lwp->lwp_status = LWP_CREATE_STAT_CONTINUED;
}
/* wakeup waiter on waitpid(2) */
lwp_waitpid_kick(parent_lwp, child_lwp);
if (_need_notify_status_changed(parent_lwp, trig_signo))
{
ext = rt_malloc(sizeof(struct lwp_siginfo_ext));
if (ext)
{
ext->sigchld.status = trig_signo;
/* TODO: signal usage is not supported */
ext->sigchld.stime = child_thr->system_time;
ext->sigchld.utime = child_thr->user_time;
}
/* generate SIGCHLD for parent */
lwp_signal_kill(parent_lwp, SIGCHLD, si_code, ext);
}
}
static int _do_signal_wakeup(rt_thread_t thread, int sig);
static rt_err_t _stop_thread_locked(rt_lwp_t self_lwp, rt_thread_t cur_thr, int signo,
lwp_siginfo_t si, lwp_sigqueue_t sq)
{
rt_err_t error;
int jobctl_stopped = self_lwp->jobctl_stopped;
rt_thread_t iter;
/* race to setup jobctl stopped flags */
if (!jobctl_stopped)
{
self_lwp->jobctl_stopped = RT_TRUE;
self_lwp->wait_reap_stp = RT_FALSE;
rt_list_for_each_entry(iter, &self_lwp->t_grp, sibling)
{
if (iter != cur_thr)
_do_signal_wakeup(iter, signo);
}
}
/**
* raise the event again so siblings is able to catch it again.
* `si` will be discarded while SIGCONT is generatd
*/
sigqueue_enqueue(sq, si);
/* release the lwp lock so we can happily suspend */
LWP_UNLOCK(self_lwp);
rt_set_errno(RT_EOK);
/* After suspension, only the SIGKILL and SIGCONT will wake this thread up */
error = rt_thread_suspend_with_flag(cur_thr, RT_KILLABLE);
if (error == RT_EOK)
{
rt_schedule();
error = rt_get_errno();
error = error > 0 ? -error : error;
}
if (!jobctl_stopped &&
(sigqueue_ismember(_SIGQ(self_lwp), SIGCONT) ||
sigqueue_ismember(_SIGQ(cur_thr), SIGCONT)))
{
/**
* if we are resumed by a SIGCONT and we are the winner of racing
* notify parent of the incoming event
*/
_notify_parent_and_leader(self_lwp, cur_thr, SIGCONT, RT_FALSE);
}
/* reacquire the lock since we release it before */
LWP_LOCK(self_lwp);
return error;
}
static void _catch_signal_locked(rt_lwp_t lwp, rt_thread_t thread, int signo,
lwp_siginfo_t siginfo, lwp_sighandler_t handler,
void *exp_frame)
{
lwp_sigset_t new_sig_mask;
lwp_sigset_t save_sig_mask;
siginfo_t usiginfo;
siginfo_t *p_usi;
/* siginfo is need for signal action */
if (_sigismember(&lwp->signal.sig_action_siginfo, signo))
{
siginfo_k2u(siginfo, &usiginfo);
p_usi = &usiginfo;
}
else
{
p_usi = RT_NULL;
}
/**
* lock is acquired by caller. Release it so that we can happily go to the
* signal handler in user space
*/
LWP_UNLOCK(lwp);
siginfo_delete(siginfo);
/* signal default handler */
if (handler == LWP_SIG_ACT_DFL)
{
lwp_sigset_t ign_sigset;
ign_sigset = lwp_sigset_init(LWP_SIG_IGNORE_SET);
if (signo == SIGCONT)
{
arch_syscall_set_errno(exp_frame, EINTR, ERESTART);
arch_thread_signal_enter(signo, p_usi, exp_frame, 0, &thread->signal.sigset_mask);
}
else if (!lwp_sigismember(&ign_sigset, signo) && !lwp->sig_protected)
{
/* for those defautl handler is to terminate process */
LOG_D("%s: default handler; and exit", __func__);
/* TODO: coredump if neccessary */
lwp_exit(lwp, LWP_CREATE_STAT_SIGNALED(signo, 0));
}
/**
* otherwise is to ignore the signal,
* -> then reacquire the lock and return
*/
}
else if (handler == LWP_SIG_ACT_IGN)
{
/* do nothing */
}
else
{
/* copy the blocked signal mask from the registered signal action */
memcpy(&new_sig_mask, &lwp->signal.sig_action_mask[signo - 1], sizeof(new_sig_mask));
if (!_sigismember(&lwp->signal.sig_action_nodefer, signo))
_sigaddset(&new_sig_mask, signo);
_thread_signal_mask(thread, LWP_SIG_MASK_CMD_BLOCK, &new_sig_mask, &save_sig_mask);
if (_sigismember(&lwp->signal.sig_action_restart, signo))
{
arch_syscall_set_errno(exp_frame, EINTR, ERESTART);
}
/**
* enter signal action of user
* Note: that the p_usi is release before entering signal action by
* reseting the kernel sp.
*/
LOG_D("%s: enter signal handler(signo=%d) at %p", __func__, signo, handler);
arch_thread_signal_enter(signo, p_usi, exp_frame, handler, &save_sig_mask);
/* the arch_thread_signal_enter() never return */
RT_ASSERT(0);
}
/* reacquire the lock because we release it before */
LWP_LOCK(lwp);
}
void lwp_thread_signal_catch(void *exp_frame)
{
struct rt_thread *thread;
struct rt_lwp *lwp;
lwp_sigqueue_t pending;
lwp_sigset_t *sig_mask;
int retry_signal_catch;
int signo;
thread = rt_thread_self();
lwp = (struct rt_lwp *)thread->lwp;
RT_ASSERT(!!lwp);
LWP_LOCK(lwp);
do {
/* if stopped process resume, we will retry to catch the signal */
retry_signal_catch = 0;
signo = 0;
/* try to peek a signal which is pending and not blocked by this thread */
if (!sigqueue_isempty(_SIGQ(thread)))
{
pending = _SIGQ(thread);
sig_mask = &thread->signal.sigset_mask;
signo = sigqueue_peek(pending, sig_mask);
}
if (!signo && !sigqueue_isempty(_SIGQ(lwp)))
{
pending = _SIGQ(lwp);
sig_mask = &thread->signal.sigset_mask;
signo = sigqueue_peek(pending, sig_mask);
}
if (signo)
{
lwp_siginfo_t siginfo;
lwp_sighandler_t handler;
LOG_D("%s(signo=%d)", __func__, signo);
siginfo = sigqueue_dequeue(pending, signo);
RT_ASSERT(siginfo != RT_NULL);
handler = _get_sighandler_locked(lwp, signo);
if (_is_stop_signal(lwp, signo) && handler == LWP_SIG_ACT_DFL)
{
/* notify the status update for parent process */
_notify_parent_and_leader(lwp, thread, signo, RT_TRUE);
LOG_D("%s: pid=%d stopped", __func__, lwp->pid);
_stop_thread_locked(lwp, thread, signo, siginfo, pending);
LOG_D("%s: pid=%d continued", __func__, lwp->pid);
/* wakeup and retry to catch signals send to us */
retry_signal_catch = 1;
}
else
{
/* do a normal, non-jobctl signal handling */
_catch_signal_locked(lwp, thread, signo, siginfo, handler, exp_frame);
}
}
} while (retry_signal_catch);
LWP_UNLOCK(lwp);
}
static int _do_signal_wakeup(rt_thread_t thread, int sig)
{
int need_schedule;
rt_sched_lock_level_t slvl;
if (!_sigismember(&thread->signal.sigset_mask, sig))
{
int stat;
rt_sched_lock(&slvl);
stat = rt_sched_thread_get_stat(thread);
if ((stat & RT_THREAD_SUSPEND_MASK) == RT_THREAD_SUSPEND_MASK)
{
if ((stat & RT_SIGNAL_COMMON_WAKEUP_MASK) != RT_SIGNAL_COMMON_WAKEUP_MASK)
{
thread->error = RT_EINTR;
rt_sched_unlock(slvl);
rt_thread_wakeup(thread);
need_schedule = 1;
}
else if ((sig == SIGKILL || sig == SIGSTOP) &&
((stat & RT_SIGNAL_KILL_WAKEUP_MASK) != RT_SIGNAL_KILL_WAKEUP_MASK))
{
thread->error = RT_EINTR;
rt_sched_unlock(slvl);
rt_thread_wakeup(thread);
need_schedule = 1;
}
else
{
rt_sched_unlock(slvl);
need_schedule = 0;
}
}
else
{
rt_sched_unlock(slvl);
need_schedule = 0;
}
RT_SCHED_DEBUG_IS_UNLOCKED;
}
else
need_schedule = 0;
return need_schedule;
}
/** find a candidate to be notified of the arrival */
static rt_thread_t _signal_find_catcher(struct rt_lwp *lwp, int signo)
{
rt_thread_t catcher = RT_NULL;
rt_thread_t candidate;
candidate = lwp->signal.sig_dispatch_thr[signo - 1];
if (candidate != RT_NULL && !_sigismember(&candidate->signal.sigset_mask, signo))
{
catcher = candidate;
}
else
{
candidate = rt_thread_self();
/** Note: lwp of current is a const value that can be safely read */
if (candidate->lwp == lwp &&
!_sigismember(&candidate->signal.sigset_mask, signo))
{
catcher = candidate;
}
else
{
rt_list_for_each_entry(candidate, &lwp->t_grp, sibling)
{
if (!_sigismember(&candidate->signal.sigset_mask, signo))
{
catcher = candidate;
break;
}
}
/* fall back to main thread */
if (catcher == RT_NULL)
catcher = rt_list_entry(lwp->t_grp.prev, struct rt_thread, sibling);
}
/* reset the cache thread to catcher (even if catcher is main thread) */
lwp->signal.sig_dispatch_thr[signo - 1] = catcher;
}
return catcher;
}
static int _siginfo_deliver_to_lwp(struct rt_lwp *lwp, lwp_siginfo_t siginfo)
{
rt_thread_t catcher;
catcher = _signal_find_catcher(lwp, siginfo->ksiginfo.signo);
sigqueue_enqueue(&lwp->signal.sig_queue, siginfo);
return _do_signal_wakeup(catcher, siginfo->ksiginfo.signo);
}
static int _siginfo_deliver_to_thread(rt_thread_t thread, lwp_siginfo_t siginfo)
{
sigqueue_enqueue(_SIGQ(thread), siginfo);
return _do_signal_wakeup(thread, siginfo->ksiginfo.signo);
}
rt_inline rt_bool_t _sighandler_is_ignored(struct rt_lwp *lwp, int signo)
{
rt_bool_t is_ignored;
lwp_sighandler_t action;
lwp_sigset_t ign_set = lwp_sigset_init(LWP_SIG_IGNORE_SET);
action = _get_sighandler_locked(lwp, signo);
if (action == LWP_SIG_ACT_IGN)
is_ignored = RT_TRUE;
else if (action == LWP_SIG_ACT_DFL && _sigismember(&ign_set, signo))
is_ignored = RT_TRUE;
else
is_ignored = RT_FALSE;
return is_ignored;
}
rt_inline rt_bool_t _sighandler_cannot_caught(struct rt_lwp *lwp, int signo)
{
return signo == SIGKILL || signo == SIGSTOP;
}
/* before signal is killed to target process/thread */
static void _before_sending_jobctl_signal(int signo, rt_lwp_t target_lwp, lwp_siginfo_t si)
{
rt_thread_t thr_iter;
rt_sched_lock_level_t slvl;
lwp_sigset_t jobctl_sigset = lwp_sigset_init(LWP_SIG_JOBCTL_SET);
LWP_ASSERT_LOCKED(target_lwp);
/**
* dequeue all the pending jobctl signals (including
* the one we are adding, since we don't want to pend it)
*/
sigqueue_discard_sigset(_SIGQ(target_lwp), &jobctl_sigset);
if (signo == SIGCONT)
{
target_lwp->jobctl_stopped = RT_FALSE;
rt_list_for_each_entry(thr_iter, &target_lwp->t_grp, sibling)
{
rt_base_t stat;
sigqueue_discard_sigset(_SIGQ(thr_iter), &jobctl_sigset);
/**
* Note: all stopped thread will be resumed
*/
rt_sched_lock(&slvl);
stat = rt_sched_thread_get_stat(thr_iter);
if ((stat & RT_THREAD_SUSPEND_MASK) == RT_THREAD_SUSPEND_MASK &&
(stat & RT_SIGNAL_KILL_WAKEUP_MASK) == 0)
{
thr_iter->error = RT_EINTR;
/**
* don't matter if we failed to resume the thread, since we
* only care about the event passing, but not ordering here
*/
rt_sched_unlock(slvl);
rt_thread_wakeup(thr_iter);
}
else
{
rt_sched_unlock(slvl);
}
}
}
else
{
rt_list_for_each_entry(thr_iter, &target_lwp->t_grp, sibling)
{
sigqueue_discard_sigset(_SIGQ(thr_iter), &jobctl_sigset);
}
}
}
rt_err_t lwp_signal_kill(struct rt_lwp *lwp, long signo, long code, lwp_siginfo_ext_t value)
{
rt_err_t ret = -1;
lwp_siginfo_t siginfo;
rt_bool_t terminated;
rt_bool_t need_schedule;
/** must be able to be suspended */
RT_DEBUG_SCHEDULER_AVAILABLE(RT_TRUE);
if (!lwp || signo < 0 || signo > _LWP_NSIG)
{
ret = -RT_EINVAL;
}
else if (signo == 0)
{
/* process exist and current process have privileges */
ret = 0;
}
else
{
LOG_D("%s(lwp=%p \"%s\",signo=%ld,code=%ld,value=%ld)",
__func__, lwp, lwp->cmd, signo, code, value);
need_schedule = RT_FALSE;
LWP_LOCK(lwp);
terminated = lwp->terminated;
/* short-circuit code for inactive task, ignored signals */
if (terminated)
{
/* no one rely on this, then free the resource */
if (value)
rt_free(value);
ret = 0;
}
else
{
siginfo = siginfo_create(rt_thread_self(), signo, code, value);
if (siginfo)
{
if (_is_jobctl_signal(lwp, signo))
_before_sending_jobctl_signal(signo, lwp, siginfo);
need_schedule = _siginfo_deliver_to_lwp(lwp, siginfo);
lwp_signal_notify(&lwp->signalfd_notify_head, siginfo);
ret = 0;
}
else
{
LOG_I("%s: siginfo malloc failed", __func__);
ret = -RT_ENOMEM;
}
}
LWP_UNLOCK(lwp);
if (need_schedule)
rt_schedule();
}
return ret;
}
static void _signal_action_flag_k2u(int signo, struct lwp_signal *signal, struct lwp_sigaction *act)
{
long flags = 0;
if (_sigismember(&signal->sig_action_nodefer, signo))
flags |= SA_NODEFER;
if (_sigismember(&signal->sig_action_onstack, signo))
flags |= SA_ONSTACK;
if (_sigismember(&signal->sig_action_restart, signo))
flags |= SA_RESTART;
if (_sigismember(&signal->sig_action_siginfo, signo))
flags |= SA_SIGINFO;
if (_sigismember(&signal->sig_action_nocldstop, signo))
flags |= SA_NOCLDSTOP;
if (_sigismember(&signal->sig_action_nocldwait, signo))
flags |= SA_NOCLDWAIT;
act->sa_flags = flags;
}
static void _signal_action_flag_u2k(int signo, struct lwp_signal *signal, const struct lwp_sigaction *act)
{
long flags = act->sa_flags;
if (flags & SA_NODEFER)
_sigaddset(&signal->sig_action_nodefer, signo);
if (flags & SA_ONSTACK)
_sigaddset(&signal->sig_action_onstack, signo);
if (flags & SA_RESTART)
_sigaddset(&signal->sig_action_restart, signo);
if (flags & SA_SIGINFO)
_sigaddset(&signal->sig_action_siginfo, signo);
if (signo == SIGCHLD)
{
/* These flags are meaningful only when establishing a handler for SIGCHLD */
if (flags & SA_NOCLDSTOP)
_sigaddset(&signal->sig_action_nocldstop, signo);
if (flags & SA_NOCLDWAIT)
_sigaddset(&signal->sig_action_nocldwait, signo);
}
#define _HANDLE_FLAGS (SA_RESTORER | SA_NODEFER | SA_ONSTACK | SA_RESTART | SA_SIGINFO | SA_NOCLDSTOP | SA_NOCLDWAIT)
if (flags & ~_HANDLE_FLAGS)
LOG_W("Unhandled flags: 0x%lx", flags & ~_HANDLE_FLAGS);
}
rt_bool_t lwp_sigisign(struct rt_lwp *lwp, int _sig)
{
unsigned long sig = _sig - 1;
return lwp->signal.sig_action[sig] == LWP_SIG_ACT_IGN;
}
rt_err_t lwp_signal_action(struct rt_lwp *lwp, int signo,
const struct lwp_sigaction *restrict act,
struct lwp_sigaction *restrict oact)
{
lwp_sighandler_t prev_handler;
lwp_sigqueue_t thread_sigq;
rt_list_t *thread_list;
rt_err_t ret = RT_EOK;
if (lwp)
{
/** acquire READ access to lwp */
LWP_LOCK(lwp);
if (oact)
{
oact->sa_mask = lwp->signal.sig_action_mask[signo - 1];
oact->__sa_handler._sa_handler = lwp->signal.sig_action[signo - 1];
oact->sa_restorer = RT_NULL;
_signal_action_flag_k2u(signo, &lwp->signal, oact);
}
if (act)
{
/**
* Note: POSIX.1-2017 requires calls to sigaction() that supply a NULL act
* argument succeed, even in the case of signals that cannot be caught or ignored
*/
if (_sighandler_cannot_caught(lwp, signo))
ret = -EINVAL;
else
{
prev_handler = _get_sighandler_locked(lwp, signo);
lwp->signal.sig_action_mask[signo - 1] = act->sa_mask;
if (act->__sa_handler._sa_handler == SIG_IGN)
{
lwp_sigset_t no_ign_set = lwp_sigset_init(LWP_SIG_NO_IGN_SET);
if (!lwp_sigismember(&no_ign_set, signo))
{
/* except those unignorable signals, discard them for proc */
lwp->signal.sig_action[signo - 1] = LWP_SIG_ACT_IGN;
}
else
{
/* POSIX.1: SIG_IGN and SIG_DFL are equivalent for SIGCONT */
lwp->signal.sig_action[signo - 1] = LWP_SIG_ACT_DFL;
}
}
else
{
lwp->signal.sig_action[signo - 1] = act->__sa_handler._sa_handler;
}
_signal_action_flag_u2k(signo, &lwp->signal, act);
/**
* Brief: Discard the pending signal if signal action is set to SIG_IGN
*
* Note: POSIX.1-2017: Setting a signal action to SIG_IGN for a signal
* that is pending shall cause the pending signal to be discarded,
* whether or not it is blocked.
*/
if (prev_handler != LWP_SIG_ACT_IGN &&
_get_sighandler_locked(lwp, signo) == LWP_SIG_ACT_IGN)
{
sigqueue_discard(_SIGQ(lwp), signo);
for (thread_list = lwp->t_grp.next;
thread_list != &lwp->t_grp;
thread_list = thread_list->next)
{
thread_sigq = _SIGQ(rt_list_entry(thread_list, struct rt_thread, sibling));
sigqueue_discard(thread_sigq, signo);
}
}
}
}
LWP_UNLOCK(lwp);
}
else
ret = -EINVAL;
return ret;
}
rt_err_t lwp_thread_signal_kill(rt_thread_t thread, long signo, long code, lwp_siginfo_ext_t value)
{
rt_err_t ret = -1;
struct rt_lwp *lwp;
lwp_siginfo_t siginfo;
rt_bool_t need_schedule;
/** must be able to be suspended */
RT_DEBUG_SCHEDULER_AVAILABLE(RT_TRUE);
LOG_D("%s(signo=%d)", __func__, signo);
if (!thread || signo < 0 || signo >= _LWP_NSIG)
{
ret = -RT_EINVAL;
}
else if (signo == 0)
{
/* thread exist and current thread have privileges */
ret = 0;
}
else
{
lwp = thread->lwp;
need_schedule = RT_FALSE;
RT_ASSERT(lwp);
LWP_LOCK(lwp);
if (!lwp)
ret = -RT_EPERM;
else if (lwp->terminated || _sighandler_is_ignored(lwp, signo))
ret = 0;
else
{
siginfo = siginfo_create(rt_thread_self(), signo, code, value);
if (siginfo)
{
need_schedule = _siginfo_deliver_to_thread(thread, siginfo);
lwp_signal_notify(&lwp->signalfd_notify_head, siginfo);
ret = 0;
}
else
{
LOG_I("%s: siginfo malloc failed", __func__);
ret = -RT_ENOMEM;
}
}
LWP_UNLOCK(lwp);
if (need_schedule)
rt_schedule();
}
return ret;
}
#ifndef ARCH_MM_MMU
void lwp_thread_sighandler_set(int sig, lwp_sighandler_t func)
{
rt_base_t level;
if (sig == 0 || sig > _LWP_NSIG)
return;
level = rt_hw_interrupt_disable();
rt_thread_self()->signal_handler[sig - 1] = func;
rt_hw_interrupt_enable(level);
}
#endif
rt_err_t lwp_thread_signal_mask(rt_thread_t thread, lwp_sig_mask_cmd_t how,
const lwp_sigset_t *sigset, lwp_sigset_t *oset)
{
rt_err_t ret = -1;
struct rt_lwp *lwp;
if (thread)
{
lwp = (struct rt_lwp *)thread->lwp;
LWP_LOCK(lwp);
if (!lwp)
{
ret = -RT_EPERM;
}
else
{
ret = 0;
_thread_signal_mask(thread, how, sigset, oset);
}
LWP_UNLOCK(lwp);
}
else
ret = -RT_EINVAL;
return ret;
}
static int _dequeue_signal(rt_thread_t thread, lwp_sigset_t *mask, siginfo_t *usi)
{
int signo;
lwp_siginfo_t si;
struct rt_lwp *lwp;
lwp_sigset_t *pending;
lwp_sigqueue_t sigqueue;
lwp = thread->lwp;
RT_ASSERT(lwp);
sigqueue = _SIGQ(thread);
pending = &sigqueue->sigset_pending;
signo = _next_signal(pending, mask);
if (!signo)
{
sigqueue = _SIGQ(lwp);
pending = &sigqueue->sigset_pending;
signo = _next_signal(pending, mask);
}
if (!signo)
return signo;
si = sigqueue_dequeue(sigqueue, signo);
RT_ASSERT(!!si);
siginfo_k2u(si, usi);
siginfo_delete(si);
return signo;
}
rt_err_t lwp_thread_signal_timedwait(rt_thread_t thread, lwp_sigset_t *sigset,
siginfo_t *usi, struct timespec *timeout)
{
rt_err_t ret;
lwp_sigset_t saved_sigset;
lwp_sigset_t blocked_sigset;
lwp_sigset_t dontwait_sigset;
int sig;
struct rt_lwp *lwp = thread->lwp;
/**
* Brief: POSIX
* If one of the signals in set is already pending for the calling thread,
* sigwaitinfo() will return immediately
*/
/* Create a mask of signals user dont want or cannot catch */
_sigdelset(sigset, SIGKILL);
_sigdelset(sigset, SIGSTOP);
_signotsets(&dontwait_sigset, sigset);
LWP_LOCK(lwp);
sig = _dequeue_signal(thread, &dontwait_sigset, usi);
LWP_UNLOCK(lwp);
if (sig)
return sig;
/**
* Brief: POSIX
* if none of the signals specified by set are pending, sigtimedwait() shall
* wait for the time interval specified in the timespec structure referenced
* by timeout.
*
* Note: If the pending signal arrives before thread suspend, the suspend
* operation will return a failure
*/
_sigandsets(&blocked_sigset, &thread->signal.sigset_mask, &dontwait_sigset);
_thread_signal_mask(thread, LWP_SIG_MASK_CMD_SET_MASK, &blocked_sigset, &saved_sigset);
if (timeout)
{
rt_tick_t time;
time = (timeout->tv_sec * RT_TICK_PER_SECOND) + ((timeout->tv_nsec * RT_TICK_PER_SECOND) / NANOSECOND_PER_SECOND);
/**
* Brief: POSIX
* If the timespec structure pointed to by timeout is zero-valued and
* if none of the signals specified by set are pending, then
* sigtimedwait() shall return immediately with an error
*/
if (time == 0)
return -EAGAIN;
rt_enter_critical();
ret = rt_thread_suspend_with_flag(thread, RT_INTERRUPTIBLE);
rt_timer_control(&(thread->thread_timer),
RT_TIMER_CTRL_SET_TIME,
&time);
rt_timer_start(&(thread->thread_timer));
rt_exit_critical();
}
else
{
/* suspend kernel forever until signal was received */
ret = rt_thread_suspend_with_flag(thread, RT_INTERRUPTIBLE);
}
if (ret == RT_EOK)
{
rt_schedule();
/* If thread->error reliable? */
if (thread->error == RT_EINTR)
ret = -EINTR;
else
ret = -EAGAIN;
}
/* else ret == -EINTR */
_thread_signal_mask(thread, LWP_SIG_MASK_CMD_SET_MASK, &saved_sigset, RT_NULL);
LWP_LOCK(lwp);
sig = _dequeue_signal(thread, &dontwait_sigset, usi);
LWP_UNLOCK(lwp);
return sig ? sig : ret;
}
void lwp_thread_signal_pending(rt_thread_t thread, lwp_sigset_t *pending)
{
struct rt_lwp *lwp;
lwp = thread->lwp;
if (lwp)
{
memset(pending, 0, sizeof(*pending));
LWP_LOCK(lwp);
sigqueue_examine(_SIGQ(thread), pending);
sigqueue_examine(_SIGQ(lwp), pending);
LWP_UNLOCK(lwp);
_sigandsets(pending, pending, &thread->signal.sigset_mask);
}
}
rt_err_t lwp_pgrp_signal_kill(rt_processgroup_t pgrp, long signo, long code,
lwp_siginfo_ext_t value)
{
struct rt_lwp *lwp;
rt_err_t rc = 0;
PGRP_ASSERT_LOCKED(pgrp);
if (pgrp)
{
rt_list_for_each_entry(lwp, &pgrp->process, pgrp_node)
{
lwp_signal_kill(lwp, signo, code, value);
}
}
return rc;
}
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