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system.c

Go to the documentation of this file.

/*
 Copyright (c) 1992-1993 The Regents of the University of California.
 All rights reserved.  See copyright.h for copyright notice and limitation 
 of liability and disclaimer of warranty provisions.
 */

#include "copyright.h"
#include <stdio.h>
#include <syscall.h>
#include "int.h"

extern int Reg[];
extern char mem[];
extern int Traptrace;

char *u_to_int_addr();

/* handle system calls */
system_break()
{
        if  ( Traptrace )
                printf("**breakpoint ");
        system_trap();
}

system_trap()
{
        int o0, o1, o2;         /* user out register values */
        int syscallno;
        extern long lseek();

        if  ( Traptrace )
        {
                printf("**System call %d\n", Reg[2]);
                dump_reg();
        }

/*      if (Reg[1] == 0)
/*      {                       /* SYS_indir */
/*              syscallno = Reg[8];     /* out reg 0 */
/*              o0 = Reg[9];
/*              o1 = Reg[10];
/*              o2 = Reg[11];
/*      }
/*      else    /* */
        {
                syscallno = Reg[2];
                o0 = Reg[4];
                o1 = Reg[5];
                o2 = Reg[6];
        }

        switch (syscallno)
        {
                case SYS_exit:  /*1*/
                        printstatistics();
                        fflush(stdout);
                        exit(0);
                        break;
                case SYS_read:  /*3*/
                        Reg[1] = 
                                read(u_to_int_fd(o0), u_to_int_addr(o1), o2);
                        break;
                case SYS_write: /*4*/
                        Reg[1] = 
                                write(u_to_int_fd(o0), u_to_int_addr(o1), o2);
                        break;

                case SYS_open:  /*5*/
                        Reg[1] = open(u_to_int_addr(o0), o1, o2); /* */
                        break;

                case SYS_close: /*6*/
                        Reg[1] = 0;     /* hack */
                        break;

                case 17:        /* 17 */
                        /* old sbreak. where did it go? */
                        Reg[1] = ((o0 / 8192) + 1) * 8192;
                        break;

                case SYS_lseek: /*19*/
                        Reg[1] = (int) lseek(u_to_int_fd(o0), (long) o1, o2);
                        break;

                case SYS_ioctl:/* 54 */
                        {       /* copied from sas -- I don't understand yet. */
                                /* see dave weaver */
#define IOCPARM_MASK    0x7f    /* parameters must be < 128 bytes */
                                int size = (o1 >> 16) & IOCPARM_MASK;
                                char ioctl_group = (o1 >> 8) & 0x00ff;
                                if ((ioctl_group == 't') && (size == 8))
                                {
                                        size = 6;
                                        o1 = (o1 & ~((IOCPARM_MASK << 16))) 
                                           | (size << 16);
                                }
                        }
                        Reg[1] = ioctl(u_to_int_fd(o0),o1,u_to_int_addr(o2));
                        Reg[1] = 0;     /* hack */
                        break;

                case SYS_fstat:         /* 62 */
                        Reg[1] = fstat(o1, o2);
                        break;

                case SYS_getpagesize:   /* 64 */
                        Reg[1] = getpagesize();
                        break;

                default:
                        printf("Unknown System call %d\n", syscallno);
                        if  ( ! Traptrace )
                                dump_reg();
                        exit(2);
                        break;
        }
        if  ( Traptrace )
        {
                printf("**Afterwards:\n");
                dump_reg();
        }
}

char *u_to_int_addr(ptr)
int ptr;
{       /* convert a user pointer to the real address   */
        /* used in the interpreter                      */

         return ((char *) ((int) mem - memoffset  + ptr));
}

u_to_int_fd(fd)
{
        if (fd > 2)
        {
                /*
                printf("No general file descriptors yet\n");
                exit(2);
                */
        }
        return (fd);            /* assume we can handle it for now */
}

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