/*      $NetBSD: signals.c,v 1.17 2020/05/23 23:42:44 ad Exp $  */

/*-
 * Copyright (c) 2010, 2011 Antti Kantee.  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 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: signals.c,v 1.17 2020/05/23 23:42:44 ad Exp $");

#include <sys/param.h>
#include <sys/atomic.h>
#include <sys/event.h>
#include <sys/proc.h>
#include <sys/signal.h>

#include <rump-sys/kern.h>

#include <rump/rump.h>
#include <rump/rumpuser.h>

const struct filterops sig_filtops = {
        .f_attach = (void *)eopnotsupp,
};

sigset_t sigcantmask;

static void
pgrp_apply(struct pgrp *pgrp, int signo, void (*apply)(struct proc *p, int))
{
        struct proc *p;

        KASSERT(mutex_owned(&proc_lock));

        LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
                mutex_enter(p->p_lock);
                apply(p, signo);
                mutex_exit(p->p_lock);
        }
}

/* RUMP_SIGMODEL_PANIC */

static void
rumpsig_panic(struct proc *p, int signo)
{

        switch (signo) {
        case SIGSYS:
        case SIGPIPE:
                break;
        default:
                panic("unhandled signal %d", signo);
        }
}

/* RUMP_SIGMODEL_IGNORE */

static void
rumpsig_ignore(struct proc *p, int signo)
{

        return;
}

/* RUMP_SIGMODEL_RAISE */

static void
rumpsig_raise(struct proc *p, int signo)
{

        if (RUMP_LOCALPROC_P(p)) {
                rumpuser_kill(p->p_pid, signo);
        } else {
                rump_sysproxy_raise(RUMP_SPVM2CTL(p->p_vmspace), signo);
        }
}

static void
rumpsig_record(struct proc *p, int signo)
{

        if (!sigismember(&p->p_sigctx.ps_sigignore, signo)) {
                sigaddset(&p->p_sigpend.sp_set, signo);
        }
}

typedef void (*rumpsig_fn)(struct proc *, int);

static rumpsig_fn rumpsig = rumpsig_raise;

/*
 * Set signal delivery model.  It would be nice if we could
 * take a functional argument.  But then we'd need some
 * OS independent way to represent a signal number and also
 * a method for easy processing (parsing is boring).
 *
 * Plus, upcalls from the rump kernel into process space except
 * via rumpuser is a somewhat gray area now.
 */
void
rump_boot_setsigmodel(enum rump_sigmodel model)
{

        switch (model) {
        case RUMP_SIGMODEL_PANIC:
                rumpsig = rumpsig_panic;
                break;
        case RUMP_SIGMODEL_IGNORE:
                rumpsig = rumpsig_ignore;
                break;
        case RUMP_SIGMODEL_RAISE:
                rumpsig = rumpsig_raise;
                break;
        case RUMP_SIGMODEL_RECORD:
                rumpsig = rumpsig_record;
                break;

        /* for compat, though I doubt anyone is using it */
        case RUMP_SIGMODEL__HOST_NOTANYMORE:
                rumpsig = rumpsig_raise;
                break;
        }
}

void
psignal(struct proc *p, int sig)
{

        rumpsig(p, sig);
}

void
pgsignal(struct pgrp *pgrp, int sig, int checktty)
{

        pgrp_apply(pgrp, sig, rumpsig);
}

void
kpsignal(struct proc *p, ksiginfo_t *ksi, void *data)
{

        rumpsig(p, ksi->ksi_signo);
}

void
kpgsignal(struct pgrp *pgrp, ksiginfo_t *ksi, void *data, int checkctty)
{

        pgrp_apply(pgrp, ksi->ksi_signo, rumpsig);
}

int
sigispending(struct lwp *l, int signo)
{
        struct proc *p = l->l_proc;
        sigset_t tset;

        tset = p->p_sigpend.sp_set;

        if (signo == 0) {
                if (firstsig(&tset) != 0)
                        return EINTR;
        } else if (sigismember(&tset, signo))
                return EINTR;
        return 0;
}

void
sigpending1(struct lwp *l, sigset_t *ss)
{
        struct proc *p = l->l_proc;

        mutex_enter(p->p_lock);
        *ss = l->l_proc->p_sigpend.sp_set;
        mutex_exit(p->p_lock);
}

int
sigismasked(struct lwp *l, int sig)
{

        return sigismember(&l->l_proc->p_sigctx.ps_sigignore, sig);
}

void
sigclear(sigpend_t *sp, const sigset_t *mask, ksiginfoq_t *kq)
{

        if (mask == NULL)
                sigemptyset(&sp->sp_set);
        else
                sigminusset(mask, &sp->sp_set);
}

void
sigclearall(struct proc *p, const sigset_t *mask, ksiginfoq_t *kq)
{

        /* don't assert proc lock, hence callable from user context */
        sigclear(&p->p_sigpend, mask, kq);
}

void
ksiginfo_queue_drain0(ksiginfoq_t *kq)
{

        if (!(TAILQ_EMPTY(kq)))
                panic("how did that get there?");
}

int
sigprocmask1(struct lwp *l, int how, const sigset_t *nss, sigset_t *oss)
{
        sigset_t *mask = &l->l_proc->p_sigctx.ps_sigignore;

        KASSERT(mutex_owned(l->l_proc->p_lock));

        if (oss)
                *oss = *mask;

        if (nss) {
                switch (how) {
                case SIG_BLOCK:
                        sigplusset(nss, mask);
                        break;
                case SIG_UNBLOCK:
                        sigminusset(nss, mask);
                        break;
                case SIG_SETMASK:
                        *mask = *nss;
                        break;
                default:
                        return EINVAL;
                }
        }

        return 0;
}

void
siginit(struct proc *p)
{

        sigemptyset(&p->p_sigctx.ps_sigignore);
        sigemptyset(&p->p_sigpend.sp_set);
}

void
sigsuspendsetup(struct lwp *l, const sigset_t *ss)
{
        /* XXX: Partial copy of kernel code, remove and use the kernel code. */
        struct proc *p = l->l_proc;

        mutex_enter(p->p_lock);
        l->l_sigrestore = 1;
        l->l_sigoldmask = l->l_sigmask;
        l->l_sigmask = *ss;
        sigminusset(&sigcantmask, &l->l_sigmask);
        mutex_exit(p->p_lock);
}

void
sigsuspendteardown(struct lwp *l)
{
        /* XXX: Copy of kernel code, remove and use the kernel code. */
        struct proc *p = l->l_proc;

        mutex_enter(p->p_lock);
        if (l->l_sigrestore) {
                l->l_sigrestore = 0;
                l->l_sigmask = l->l_sigoldmask;
        }
        mutex_exit(p->p_lock);
}