usr/src/usr.bin/pascal/px/int.c

/* Copyright (c) 1979 Regents of the University of California */

static char sccsid[] = "@(#)int.c 1.1 %G%";

/*
 * px - interpreter for Berkeley Pascal
 * Version 3.0 Winter 1979
 *
 * Original version for the PDP 11/70 authored by:
 * Bill Joy, Charles Haley, Ken Thompson
 *
 * Rewritten for VAX 11/780 by Kirk McKusick
 */

#include        <signal.h>
#include        "vars.h"
#include        "objfmt.h"

main(ac,av)

long    ac;
char    **av;

{
register long bytesread, block;
register char *objprog, *file;
register FILE *prog;
struct   pxhdr pxhd;
#define  pipe 3
#define  pipesize 4096

/*
 * Initialize everything
 */
_argc = ac;
_argv = av;
_nodump = 0;
\f
/*
 * Determine how PX was invoked, and how to process the program
 */
if (_argv[0][0] == '-' && _argv[0][1] == 'o')
        {
        file = &_argv[0][2];
        _mode = PIX;
        }
else if (_argc <= 1)
        {
        file = "obj";
        _mode = PX;
        }
else if (_argv[1][0] != '-')
        {
        file = _argv[1];
        _mode = PX;
        }
else if (_argv[1][1] == 0)
        {
        file = _argv[0];
        _mode = PIPE;
        _argc -= 1;
        _argv[1] = _argv[0];
        _argv = &_argv[1];
        }
else
        {
        fputs("Improper specification of object file to PX\n",stderr);
        exit(1);
        }
\f
/*
 * Process program header information
 */
if (_mode == PIPE)
        read(pipe,&pxhd,sizeof(struct pxhdr));
else
        {
        prog = fopen(file,"r");
        if (prog == NULL)
                {
                perror(file);
                exit(1);
                }
        fseek(prog,HEADER_BYTES-sizeof(struct pxhdr),0);
        fread(&pxhd,sizeof(struct pxhdr),1,prog);
        }
if (pxhd.maketime < createtime)
        {
        fprintf(stderr,"%s is obsolete and must be recompiled\n",file);
        exit(1);
        }
if (pxhd.magicnum != 0403)
        {
        fprintf(stderr,"%s is not a Pascal program\n",file);
        exit(1);
        }
\f
/*
 * Load program into memory
 */
objprog = malloc(pxhd.objsize);
if (_mode == PIPE)
        {
        bytesread = 0;
        do
                {
                block = read(pipe,objprog+bytesread,pipesize);
                bytesread += block;
                }
                while (block);
        }
else
        {
        bytesread = fread(objprog,1,pxhd.objsize,prog);
        fclose(prog);
        if (_mode == PIX)
                unlink(file);
        }
if (bytesread != pxhd.objsize)
        {
        fprintf(stderr,"Read error occurred while loading %s\n",file);
        exit(1);
        }
if (_mode == PIX)
        fputs("Execution begins...\n",stderr);
/*
 * set interpreter to catch expected signals and begin interpretation
 */
signal(SIGILL,syserr);
signal(SIGBUS,syserr);
signal(SIGSYS,syserr);
if (signal(SIGINT,SIG_IGN) != SIG_IGN)
        signal(SIGINT,intr);
signal(SIGSEGV,memsize);
signal(SIGFPE,except);
signal(SIGTRAP,liberr);
interpreter(objprog);
/*
 * reset signals, deallocate memory, and exit normally
 */
signal(SIGINT,SIG_IGN);
signal(SIGSEGV,SIG_DFL);
signal(SIGFPE,SIG_DFL);
signal(SIGTRAP,SIG_DFL);
signal(SIGILL,SIG_DFL);
signal(SIGBUS,SIG_DFL);
signal(SIGSYS,SIG_DFL);
PFLUSH();
/* pfree(objprog); */
psexit(0);
}