/* $NetBSD: syscall.c,v 1.27 2023/10/05 19:41:06 ad Exp $ */

/*-
 * Copyright (c) 2007 Jared D. McNeill <jmcneill@invisible.ca>
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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: syscall.c,v 1.27 2023/10/05 19:41:06 ad Exp $");

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/lwp.h>
#include <sys/sched.h>
#include <sys/ktrace.h>
#include <sys/syscall.h>
#include <sys/syscallvar.h>
#include <sys/syscallargs.h>

#include <sys/userret.h>
#include <machine/pcb.h>
#include <machine/thunk.h>
#include <machine/machdep.h>

void
md_child_return(struct lwp *l)
{
        register_t rval[2];
        struct pcb *pcb = lwp_getpcb(l);
        ucontext_t *ucp = &pcb->pcb_userret_ucp;

        /* return value zero */
        rval[0] = 0;
        rval[1] = 0;
        md_syscall_set_returnargs(l, ucp, 0, rval);

        aprint_debug("child return! lwp %p\n", l);
        userret(l);
}

/*
 * Process the tail end of a posix_spawn() for the child.
 */
void
cpu_spawn_return(struct lwp *l)
{

        userret(l);
}

extern const char *const syscallnames[];

static void syscall_args_print(lwp_t *l, int code, int nargs, int argsize,
        register_t *args);
static void syscall_retvals_print(lwp_t *l, lwp_t *clwp,
        int code, int nargs, register_t *args, int error, register_t *rval);


void
syscall(void)
{       
        lwp_t *l = curlwp;
        const struct proc * const p = l->l_proc;
        const struct sysent *callp;
        struct pcb *pcb = lwp_getpcb(l);
        ucontext_t *ucp = &pcb->pcb_userret_ucp;
        register_t copyargs[2+SYS_MAXSYSARGS];
        register_t *args;
        register_t rval[2];
        uint32_t code, opcode;
        uint nargs, argsize;
        int error;

        /* system call accounting */
        curcpu()->ci_data.cpu_nsyscall++;

        /* XXX do we want do do emulation? */
        md_syscall_get_opcode(ucp, &opcode);
        md_syscall_get_syscallnumber(ucp, &code);
        code &= (SYS_NSYSENT -1);

        callp   = p->p_emul->e_sysent + code;
        nargs   = callp->sy_narg;
        argsize = callp->sy_argsize;

        args  = copyargs;
        rval[0] = rval[1] = 0;
        error = md_syscall_getargs(l, ucp, nargs, argsize, args);

#if 0
        aprint_debug("syscall no. %d, ", code);
        aprint_debug("nargs %d, argsize %d =>  ", nargs, argsize);
        thunk_printf_debug("syscall no. %d, ", code);
        thunk_printf_debug("nargs %d, argsize %d =>  ", nargs, argsize);
#endif

        /*
         * TODO change the pre and post printing into functions so they can be
         * easily adjusted and dont clobber up this space
         */

        if (!error)
                syscall_args_print(l, code, nargs, argsize, args);

        md_syscall_inc_pc(ucp, opcode);

        if (!error) {
                error = sy_invoke(callp, l, args, rval, code);
        }

        syscall_retvals_print(l, curlwp, code, nargs, args, error, rval);

//out:
        switch (error) {
        default:
                /* FALLTHROUGH */
        case 0:
                md_syscall_set_returnargs(l, ucp, error, rval);
                /* FALLTHROUGH */
        case EJUSTRETURN:
                break;
        case ERESTART:
                md_syscall_dec_pc(ucp, opcode);
                /* nothing to do */
                break;
        }
        //thunk_printf_debug("end of syscall : return to userland\n");
//if (code != 4) thunk_printf("userret() code %d\n", code);
}


static void
syscall_args_print(lwp_t *l, int code, int nargs, int argsize, register_t *args)
{
        char **argv, **envp;

return;
        if (code != 4) {
                thunk_printf("lwp %p, code %3d, nargs %d, argsize %3d\t%s(", 
                        l, code, nargs, argsize, syscallnames[code]);
                switch (code) {
                case 5:
                        thunk_printf("\"%s\", %"PRIx32", %"PRIx32"", (char *) (args[0]), (uint) args[1], (uint) args[2]);
                        break;
                case 33:
                        thunk_printf("\"%s\", %"PRIx32"", (char *) (args[0]), (uint) args[1]);
                        break;
                case 50:
                        thunk_printf("\"%s\"", (char *) (args[0]));
                        break;
                case 58:
                        thunk_printf("\"%s\", %"PRIx32", %"PRIx32"", (char *) (args[0]), (uint) (args[1]), (uint) args[2]);
                        break;
                case 59:
                        thunk_printf("\"%s\", [", (char *) (args[0]));
                        argv = (char **) (args[1]);
                        if (*argv) {
                                while (*argv) {
                                        thunk_printf("\"%s\", ", *argv);
                                        argv++;
                                }
                                thunk_printf("\b\b");
                        }
                        thunk_printf("], [");
                        envp = (char **) (args[2]);
                        if (*envp) {
                                while (*envp) {
                                        thunk_printf("\"%s\", ", *envp);
                                        envp++;
                                }
                                thunk_printf("\b\b");
                        }
                        thunk_printf("]");
                        break;
                default:
                        for (int i = 0; i < nargs; i++)
                                thunk_printf("%"PRIx32", ", (uint) args[i]);
                        if (nargs)
                                thunk_printf("\b\b");
                }
                thunk_printf(") ");
        }
#if 0
        if ((code == 4)) {
//              thunk_printf_debug("[us] %s", (char *) args[1]);
                thunk_printf("[us] %s", (char *) args[1]);
        }
#endif
}


static void
syscall_retvals_print(lwp_t *l, lwp_t *clwp, int code, int nargs, register_t *args, int error, register_t *rval)
{
        char const *errstr;

return;
        switch (error) {
        case EJUSTRETURN:
                errstr = "EJUSTRETURN";
                break;
        case EAGAIN:
                errstr = "EGAIN";
                break;
        default:
                errstr = "OK";
        }
        if (code != 4)
                thunk_printf("=> %s: %d, (%"PRIx32", %"PRIx32")\n",
                        errstr, error, (uint) (rval[0]), (uint) (rval[1]));
}