fix code to read from pipes to request only what it needs

[unix-history] / usr / src / usr.bin / pascal / px / int.c

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

static char sccsid[] = "@(#)int.c 1.4 %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	"whoami.h"
#include	"vars.h"
#include	"objfmt.h"

main(ac,av)

	int	ac;
	char	**av;

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

	/*
	 * Initialize everything
	 */
	_argc = ac;
	_argv = av;
	_nodump = FALSE;
\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,(long)(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		fprintf(stderr,"%s is obsolete and must be recompiled\n",file);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 != MAGICNUM) {
		fprintf(stderr,"%s is not a Pascal interpreter file\n",file);
		exit(1);
	}
\f
	/*
	 * Load program into memory
	 */
	objprog = malloc((int)pxhd.objsize);
	if (_mode == PIPE) {
		bytestoread = pxhd.objsize;
		bytesread = 0;
		do	{
			block = read(pipe,(int)(objprog+bytesread),bytestoread);
			if (block > 0) {
				bytesread += block;
				bytestoread -= block;
			}
		} while (block > 0);
	} else {
		bytesread = fread(objprog,1,(int)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);
	/*
	 * do it
	 */
	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);
}