From 842d41c923d3f1feb7ec8b23dbcf236d7fdb4b78 Mon Sep 17 00:00:00 2001
From: Kirk McKusick <mckusic@ucbvax.Berkeley.EDU>
Date: Sun, 21 Jun 1981 23:46:37 -0800
Subject: [PATCH] fix code to read from pipes to request only what it needs

SCCS-vsn: usr.bin/pascal/px/int.c 1.4
---
 usr/src/usr.bin/pascal/px/int.c | 72 +++++++++++++--------------------
 1 file changed, 28 insertions(+), 44 deletions(-)

diff --git a/usr/src/usr.bin/pascal/px/int.c b/usr/src/usr.bin/pascal/px/int.c
index 072e16666c..28e959bdd7 100644
--- a/usr/src/usr.bin/pascal/px/int.c
+++ b/usr/src/usr.bin/pascal/px/int.c
@@ -24,11 +24,10 @@ main(ac,av)
 
 {
 	register char *objprog, *file;
-	register long bytesread, block;
+	register long bytesread, bytestoread, block;
 	register FILE *prog;
 	struct	 pxhdr pxhd;
 #	define	 pipe 3
-#	define	 pipesize 4096
 
 	/*
 	 * Initialize everything
@@ -40,88 +39,73 @@ main(ac,av)
 	/*
 	 * Determine how PX was invoked, and how to process the program 
 	 */
-	if (_argv[0][0] == '-' && _argv[0][1] == 'o')
-		{
+	if (_argv[0][0] == '-' && _argv[0][1] == 'o') {
 		file = &_argv[0][2];
 		_mode = PIX;
-		}
-	else if (_argc <= 1)
-		{
+	} else if (_argc <= 1) {
 		file = "obj";
 		_mode = PX;
-		}
-	else if (_argv[1][0] != '-')
-		{
+	} else if (_argv[1][0] != '-') {
 		file = _argv[1];
 		_mode = PX;
-		}
-	else if (_argv[1][1] == 0)
-		{
+	} else if (_argv[1][1] == 0) {
 		file = _argv[0];
 		_mode = PIPE;
 		_argc -= 1;
 		_argv[1] = _argv[0];
 		_argv = &_argv[1];
-		}
-	else
-		{
+	} else {
 		fputs("Improper specification of object file to PX\n",stderr);
 		exit(1);
-		}
+	}
 
 	/*
 	 * Process program header information
 	 */
-	if (_mode == PIPE)
+	if (_mode == PIPE) {
 		read(pipe,&pxhd,sizeof(struct pxhdr));
-	else
-		{
+	} else {
 		prog = fopen(file,"r");
-		if (prog == NULL)
-			{
+		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)
-		{
+	}
+	if (pxhd.maketime < createtime) {
 		fprintf(stderr,"%s is obsolete and must be recompiled\n",file);
 		exit(1);
-		}
-	if (pxhd.magicnum != MAGICNUM)
-		{
+	}
+	if (pxhd.magicnum != MAGICNUM) {
 		fprintf(stderr,"%s is not a Pascal interpreter file\n",file);
 		exit(1);
-		}
+	}
 
 	/*
 	 * Load program into memory
 	 */
 	objprog = malloc((int)pxhd.objsize);
-	if (_mode == PIPE)
-		{
+	if (_mode == PIPE) {
+		bytestoread = pxhd.objsize;
 		bytesread = 0;
-		do
-			{
-			block = read(pipe,(int)(objprog+bytesread),pipesize);
-			bytesread += block;
+		do	{
+			block = read(pipe,(int)(objprog+bytesread),bytestoread);
+			if (block > 0) {
+				bytesread += block;
+				bytestoread -= block;
 			}
-			while (block);
-		}
-	else
-		{
+		} while (block > 0);
+	} else {
 		bytesread = fread(objprog,1,(int)pxhd.objsize,prog);
 		fclose(prog);
 		if (_mode == PIX)
 			unlink(file);
-		}
-	if (bytesread != pxhd.objsize)
-		{
+	}
+	if (bytesread != pxhd.objsize) {
 		fprintf(stderr,"Read error occurred while loading %s\n",file);
 		exit(1);
-		}
+	}
 	if (_mode == PIX)
 		fputs("Execution begins...\n",stderr);
 	/*
-- 
2.20.1