/*
 * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
 * All rights reserved.
 *
 * 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 AUTHOR ``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 AUTHOR 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.
 *
 */

#include "namespace.h"
#include <sys/signalvar.h>
#include <machine/tls.h>
#include <signal.h>
#include <errno.h>
#include <string.h>
#include <pthread.h>
#include "un-namespace.h"

#include "thr_private.h"

#if defined(_PTHREADS_DEBUGGING) || defined(_PTHREADS_DEBUGGING2)
#include <sys/file.h>
#include <stdio.h>
#endif

/* #define DEBUG_SIGNAL */
#ifdef DEBUG_SIGNAL
#define DBG_MSG         stdout_debug
#else
#define DBG_MSG(x...)
#endif

int     __sigwait(const sigset_t *set, int *sig);
int     __sigwaitinfo(const sigset_t *set, siginfo_t *info);
int     __sigtimedwait(const sigset_t *set, siginfo_t *info,
                const struct timespec * timeout);

#if defined(_PTHREADS_DEBUGGING) || defined(_PTHREADS_DEBUGGING2)
static void _thr_debug_sig(int signo);
#endif

static void
sigcancel_handler(int sig __unused, siginfo_t *info __unused,
        ucontext_t *ucp __unused)
{
        pthread_t curthread = tls_get_curthread();

        if (curthread->cancelflags & THR_CANCEL_AT_POINT)
                _pthread_testcancel();
        _thr_ast(curthread);
}

void
_thr_ast(pthread_t curthread)
{
        if (!THR_IN_CRITICAL(curthread)) {
                if (__predict_false((curthread->flags &
                    (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED))
                        == THR_FLAGS_NEED_SUSPEND))
                        _thr_suspend_check(curthread);
        }
}

void
_thr_suspend_check(pthread_t curthread)
{
        umtx_t cycle;

        /*
         * Blocks SIGCANCEL which other threads must send.
         */
        _thr_signal_block(curthread);

        /*
         * Increase critical_count, here we don't use THR_LOCK/UNLOCK
         * because we are leaf code, we don't want to recursively call
         * ourself.
         */
        curthread->critical_count++;
        THR_UMTX_LOCK(curthread, &(curthread)->lock);
        while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND |
                THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) {
                curthread->cycle++;
                cycle = curthread->cycle;

                /* Wake the thread suspending us. */
                _thr_umtx_wake(&curthread->cycle, 0);

                /*
                 * if we are from pthread_exit, we don't want to
                 * suspend, just go and die.
                 */
                if (curthread->state == PS_DEAD)
                        break;
                curthread->flags |= THR_FLAGS_SUSPENDED;
                THR_UMTX_UNLOCK(curthread, &(curthread)->lock);
                _thr_umtx_wait(&curthread->cycle, cycle, NULL, 0);
                THR_UMTX_LOCK(curthread, &(curthread)->lock);
                curthread->flags &= ~THR_FLAGS_SUSPENDED;
        }
        THR_UMTX_UNLOCK(curthread, &(curthread)->lock);
        curthread->critical_count--;

        _thr_signal_unblock(curthread);
}

void
_thr_signal_init(void)
{
        struct sigaction act;

        /* Install cancel handler. */
        SIGEMPTYSET(act.sa_mask);
        act.sa_flags = SA_SIGINFO | SA_RESTART;
        act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler;
        __sys_sigaction(SIGCANCEL, &act, NULL);

#if defined(_PTHREADS_DEBUGGING) || defined(_PTHREADS_DEBUGGING2)
        /*
         * If enabled, rwlock, mutex, and condition variable operations
         * are recorded in a text buffer and signal 63 dumps the buffer
         * to /tmp/cond${pid}.log.
         */
        act.sa_flags = SA_RESTART;
        act.sa_handler = _thr_debug_sig;
        __sys_sigaction(63, &act, NULL);
#endif
}

void
_thr_signal_deinit(void)
{
}

int
_sigaction(int sig, const struct sigaction * act, struct sigaction * oact)
{
        /* Check if the signal number is out of range: */
        if (sig < 1 || sig > _SIG_MAXSIG || sig == SIGCANCEL) {
                /* Return an invalid argument: */
                errno = EINVAL;
                return (-1);
        }

        return __sys_sigaction(sig, act, oact);
}

__strong_reference(_sigaction, sigaction);

int
_sigprocmask(int how, const sigset_t *set, sigset_t *oset)
{
        const sigset_t *p = set;
        sigset_t newset;

        if (how != SIG_UNBLOCK) {
                if (set != NULL) {
                        newset = *set;
                        SIGDELSET(newset, SIGCANCEL);
                        p = &newset;
                }
        }
        return (__sys_sigprocmask(how, p, oset));
}

__strong_reference(_sigprocmask, sigprocmask);

int
_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
{
        if (_sigprocmask(how, set, oset))
                return (errno);
        return (0);
}

__strong_reference(_pthread_sigmask, pthread_sigmask);

int
_sigsuspend(const sigset_t * set)
{
        pthread_t curthread = tls_get_curthread();
        sigset_t newset;
        const sigset_t *pset;
        int oldcancel;
        int ret;

        if (SIGISMEMBER(*set, SIGCANCEL)) {
                newset = *set;
                SIGDELSET(newset, SIGCANCEL);
                pset = &newset;
        } else
                pset = set;

        oldcancel = _thr_cancel_enter(curthread);
        ret = __sys_sigsuspend(pset);
        _thr_cancel_leave(curthread, oldcancel);

        return (ret);
}

__strong_reference(_sigsuspend, sigsuspend);

int
__sigtimedwait(const sigset_t *set, siginfo_t *info,
        const struct timespec * timeout)
{
        pthread_t curthread = tls_get_curthread();
        sigset_t newset;
        const sigset_t *pset;
        int oldcancel;
        int ret;

        if (SIGISMEMBER(*set, SIGCANCEL)) {
                newset = *set;
                SIGDELSET(newset, SIGCANCEL);
                pset = &newset;
        } else
                pset = set;
        oldcancel = _thr_cancel_enter(curthread);
        ret = __sys_sigtimedwait(pset, info, timeout);
        _thr_cancel_leave(curthread, oldcancel);
        return (ret);
}

__strong_reference(__sigtimedwait, sigtimedwait);

int
__sigwaitinfo(const sigset_t *set, siginfo_t *info)
{
        pthread_t curthread = tls_get_curthread();
        sigset_t newset;
        const sigset_t *pset;
        int oldcancel;
        int ret;

        if (SIGISMEMBER(*set, SIGCANCEL)) {
                newset = *set;
                SIGDELSET(newset, SIGCANCEL);
                pset = &newset;
        } else
                pset = set;

        oldcancel = _thr_cancel_enter(curthread);
        ret = __sys_sigwaitinfo(pset, info);
        _thr_cancel_leave(curthread, oldcancel);
        return (ret);
}

__strong_reference(__sigwaitinfo, sigwaitinfo);

int
__sigwait(const sigset_t *set, int *sig)
{
        int s;

        s = __sigwaitinfo(set, NULL);
        if (s > 0) {
                *sig = s;
                return (0);
        }
        return (errno);
}

__strong_reference(__sigwait, sigwait);

#if defined(_PTHREADS_DEBUGGING) || defined(_PTHREADS_DEBUGGING2)

#define LOGBUF_SIZE     (4 * 1024 * 1024)
#define LOGBUF_MASK     (LOGBUF_SIZE - 1)

char LogBuf[LOGBUF_SIZE];
unsigned long LogWIndex;

void
_thr_log(const char *buf, size_t bytes)
{
        pthread_t curthread;
        unsigned long i;
        char prefix[32];
        size_t plen;

        curthread = tls_get_curthread();
        if (curthread) {
                plen = snprintf(prefix, sizeof(prefix), "%d.%d: ",
                                (int)__sys_getpid(),
                                curthread->tid);
        } else {
                plen = snprintf(prefix, sizeof(prefix), "unknown: ");
        }

        if (bytes == 0)
                bytes = strlen(buf);
        i = atomic_fetchadd_long(&LogWIndex, plen + bytes);
        i = i & LOGBUF_MASK;
        if (plen <= (size_t)(LOGBUF_SIZE - i)) {
                bcopy(prefix, LogBuf + i, plen);
        } else {
                bcopy(prefix, LogBuf + i, LOGBUF_SIZE - i);
                plen -= LOGBUF_SIZE - i;
                bcopy(prefix, LogBuf, plen);
        }

        i += plen;
        i = i & LOGBUF_MASK;
        if (bytes <= (size_t)(LOGBUF_SIZE - i)) {
                bcopy(buf, LogBuf + i, bytes);
        } else {
                bcopy(buf, LogBuf + i, LOGBUF_SIZE - i);
                bytes -= LOGBUF_SIZE - i;
                bcopy(buf, LogBuf, bytes);
        }
}

static void
_thr_debug_sig(int signo __unused)
{
        char buf[256];
        int fd;
        unsigned long i;

        snprintf(buf, sizeof(buf), "/tmp/cond%d.log", (int)__sys_getpid());
        fd = open(buf, O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC, 0666);
        if (fd >= 0) {
                i = LogWIndex;
                if (i < LOGBUF_SIZE) {
                        write(fd, LogBuf, i);
                } else {
                        i &= LOGBUF_MASK;
                        write(fd, LogBuf + i, LOGBUF_SIZE - i);
                        write(fd, LogBuf, i);
                }
                close(fd);
        }
}

#endif