/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup POSIXAPI
*
* @brief Send a Signal to a Process
*/
/*
* kill() support routine
*
* COPYRIGHT (c) 1989-2009.
* On-Line Applications Research Corporation (OAR).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <pthread.h>
#include <signal.h>
#include <errno.h>
#include <rtems/posix/pthreadimpl.h>
#include <rtems/posix/psignalimpl.h>
#include <rtems/score/isr.h>
#include <rtems/score/statesimpl.h>
#include <rtems/seterr.h>
/*
* If you enable this, then you get printk() feedback on each path
* and the input to the decision that lead to the decision. Hopefully
* this will help in debugging the algorithm that distributes process
* signals to individual threads.
*/
/* #define DEBUG_SIGNAL_PROCESSING */
#if defined(DEBUG_SIGNAL_PROCESSING)
#include <rtems/bspIo.h>
#define DEBUG_STEP(_x) printk(_x)
#else
#define DEBUG_STEP(_x)
#endif
/*
* 3.3.2 Send a Signal to a Process, P1003.1b-1993, p. 68
*
* NOTE: Behavior of kill() depends on _POSIX_SAVED_IDS.
*/
#define _POSIX_signals_Is_interested( _api, _mask ) \
( (_api)->signals_unblocked & (_mask) )
int _POSIX_signals_Send(
pid_t pid,
int sig,
const union sigval *value
)
{
sigset_t mask;
POSIX_API_Control *api;
uint32_t the_api;
uint32_t index;
uint32_t maximum;
Objects_Information *the_info;
Objects_Control **object_table;
Thread_Control *the_thread;
Thread_Control *interested;
Priority_Control interested_priority;
Chain_Node *the_node;
siginfo_t siginfo_struct;
siginfo_t *siginfo;
POSIX_signals_Siginfo_node *psiginfo;
Thread_queue_Heads *heads;
Thread_queue_Context queue_context;
Per_CPU_Control *cpu_self;
/*
* Only supported for the "calling process" (i.e. this node).
*/
if ( pid != getpid() )
rtems_set_errno_and_return_minus_one( ESRCH );
/*
* Validate the signal passed.
*/
if ( !sig )
rtems_set_errno_and_return_minus_one( EINVAL );
if ( !is_valid_signo(sig) )
rtems_set_errno_and_return_minus_one( EINVAL );
/*
* If the signal is being ignored, then we are out of here.
*/
if ( _POSIX_signals_Vectors[ sig ].sa_handler == SIG_IGN )
return 0;
/*
* P1003.1c/Draft 10, p. 33 says that certain signals should always
* be directed to the executing thread such as those caused by hardware
* faults.
*/
if ( (sig == SIGFPE) || (sig == SIGILL) || (sig == SIGSEGV ) )
return pthread_kill( pthread_self(), sig );
mask = signo_to_mask( sig );
/*
* Build up a siginfo structure
*/
siginfo = &siginfo_struct;
siginfo->si_signo = sig;
siginfo->si_code = SI_USER;
if ( !value ) {
siginfo->si_value.sival_int = 0;
} else {
siginfo->si_value = *value;
}
/* FIXME: https://devel.rtems.org/ticket/2690 */
cpu_self = _Thread_Dispatch_disable();
/*
* Is the currently executing thread interested? If so then it will
* get it an execute it as soon as the dispatcher executes.
*/
the_thread = _Per_CPU_Get_executing( cpu_self );
api = the_thread->API_Extensions[ THREAD_API_POSIX ];
if ( _POSIX_signals_Is_interested( api, mask ) ) {
goto process_it;
}
/*
* Is an interested thread waiting for this signal (sigwait())?
*
* There is no requirement on the order of threads pending on a sigwait().
*/
/* XXX violation of visibility -- need to define thread queue support */
heads = _POSIX_signals_Wait_queue.Queue.heads;
if ( heads != NULL ) {
Chain_Control *the_chain = &heads->Heads.Fifo;
for ( the_node = _Chain_First( the_chain );
!_Chain_Is_tail( the_chain, the_node ) ;
the_node = the_node->next ) {
Scheduler_Node *scheduler_node;
scheduler_node = SCHEDULER_NODE_OF_WAIT_PRIORITY_NODE( the_node );
the_thread = _Scheduler_Node_get_owner( scheduler_node );
api = the_thread->API_Extensions[ THREAD_API_POSIX ];
#if defined(DEBUG_SIGNAL_PROCESSING)
printk( "Waiting Thread=%p option=0x%08x mask=0x%08x blocked=0x%08x\n",
the_thread, the_thread->Wait.option, mask, ~api->signals_unblocked);
#endif
/*
* Is this thread is actually blocked waiting for the signal?
*/
if (the_thread->Wait.option & mask)
goto process_it;
/*
* Is this thread is blocked waiting for another signal but has
* not blocked this one?
*/
if (api->signals_unblocked & mask)
goto process_it;
}
}
/*
* Is any other thread interested? The highest priority interested
* thread is selected. In the event of a tie, then the following
* additional criteria is used:
*
* + ready thread over blocked
* + blocked on call interruptible by signal (can return EINTR)
* + blocked on call not interruptible by signal
*
* This looks at every thread in the system regardless of the creating API.
*
* NOTES:
*
* + rtems internal threads do not receive signals.
*/
interested = NULL;
interested_priority = UINT64_MAX;
for (the_api = OBJECTS_CLASSIC_API; the_api <= OBJECTS_APIS_LAST; the_api++) {
_Assert( _Objects_Information_table[ the_api ] != NULL );
the_info = _Objects_Information_table[ the_api ][ 1 ];
if ( !the_info )
continue;
maximum = _Objects_Get_maximum_index( the_info );
object_table = the_info->local_table;
for ( index = 0 ; index < maximum ; ++index ) {
the_thread = (Thread_Control *) object_table[ index ];
if ( !the_thread )
continue;
#if defined(DEBUG_SIGNAL_PROCESSING)
printk("\n 0x%08x/0x%08x %d/%d 0x%08x 1",
the_thread->Object.id,
((interested) ? interested->Object.id : 0),
_Thread_Get_priority( the_thread ), interested_priority,
the_thread->current_state
);
#endif
/*
* If this thread is of lower priority than the interested thread,
* go on to the next thread.
*/
if ( _Thread_Get_priority( the_thread ) > interested_priority )
continue;
DEBUG_STEP("2");
/*
* If this thread is not interested, then go on to the next thread.
*/
api = the_thread->API_Extensions[ THREAD_API_POSIX ];
#if defined(RTEMS_DEBUG)
if ( !api )
continue;
#endif
if ( !_POSIX_signals_Is_interested( api, mask ) )
continue;
DEBUG_STEP("3");
/*
* Now we know the thread under consideration is interested.
* If the thread under consideration is of higher priority, then
* it becomes the interested thread.
*
* NOTE: We initialized interested_priority to PRIORITY_MAXIMUM + 1
* so we never have to worry about deferencing a NULL
* interested thread.
*/
if ( _Thread_Get_priority( the_thread ) < interested_priority ) {
interested = the_thread;
interested_priority = _Thread_Get_priority( the_thread );
continue;
}
DEBUG_STEP("4");
/*
* Now the thread and the interested thread have the same priority.
* We have to sort through the combinations of blocked/not blocked
* and blocking interruptibutable by signal.
*
* If the interested thread is ready, don't think about changing.
*/
if ( interested && !_States_Is_ready( interested->current_state ) ) {
/* preferred ready over blocked */
DEBUG_STEP("5");
if ( _States_Is_ready( the_thread->current_state ) ) {
interested = the_thread;
interested_priority = _Thread_Get_priority( the_thread );
continue;
}
DEBUG_STEP("6");
/* prefer blocked/interruptible over blocked/not interruptible */
if ( !_States_Is_interruptible_by_signal(interested->current_state) ) {
DEBUG_STEP("7");
if ( _States_Is_interruptible_by_signal(the_thread->current_state) ) {
DEBUG_STEP("8");
interested = the_thread;
interested_priority = _Thread_Get_priority( the_thread );
continue;
}
}
}
}
}
if ( interested ) {
the_thread = interested;
goto process_it;
}
/*
* OK so no threads were interested right now. It will be left on the
* global pending until a thread receives it. The global set of threads
* can change interest in this signal in one of the following ways:
*
* + a thread is created with the signal unblocked,
* + pthread_sigmask() unblocks the signal,
* + sigprocmask() unblocks the signal, OR
* + sigaction() which changes the handler to SIG_IGN.
*/
goto post_process_signal;
/*
* We found a thread which was interested, so now we mark that this
* thread needs to do the post context switch extension so it can
* evaluate the signals pending.
*/
process_it:
/*
* Returns true if the signal was synchronously given to a thread
* blocked waiting for the signal.
*/
if ( _POSIX_signals_Unblock_thread( the_thread, sig, siginfo ) ) {
_Thread_Dispatch_enable( cpu_self );
return 0;
}
post_process_signal:
/*
* We may have woken up a thread but we definitely need to post the
* signal to the process wide information set.
*/
_POSIX_signals_Set_process_signals( mask );
_Thread_queue_Context_initialize( &queue_context );
_POSIX_signals_Acquire( &queue_context );
if ( _POSIX_signals_Vectors[ sig ].sa_flags == SA_SIGINFO ) {
psiginfo = (POSIX_signals_Siginfo_node *)
_Chain_Get_unprotected( &_POSIX_signals_Inactive_siginfo );
if ( !psiginfo ) {
_POSIX_signals_Release( &queue_context );
_Thread_Dispatch_enable( cpu_self );
rtems_set_errno_and_return_minus_one( EAGAIN );
}
psiginfo->Info = *siginfo;
_Chain_Append_unprotected(
&_POSIX_signals_Siginfo[ sig ],
&psiginfo->Node
);
}
_POSIX_signals_Release( &queue_context );
DEBUG_STEP("\n");
_Thread_Dispatch_enable( cpu_self );
return 0;
}
