shithub: riscv

Download patch

ref: 7feab4dc5913c8d072d57e9cc7cc7b3815037fe8
parent: 4adb1d68d1a958c2ee3c5cfe2e26968e13dcfc1b
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Sat Apr 25 18:16:44 EDT 2020 

cc: simplify macexpand() and off-by-one error

the caller of macexpand() needs one more byte in
the buffer to append peekc.

make macexpand() actually check for buffer overflow.

just use strdup() to duplicate include file name
instead of the hunk dance.

move GETC() macro in cc.h


--- a/sys/src/cmd/cc/cc.h
+++ b/sys/src/cmd/cc/cc.h
@@ -143,6 +143,8 @@
 	int	c;
 } fi;
 
+#define	GETC()	((--fi.c < 0)? filbuf(): (*fi.p++ & 0xff))
+
 struct	Io
 {
 	Io*	link;
--- a/sys/src/cmd/cc/lex.c
+++ b/sys/src/cmd/cc/lex.c
@@ -430,7 +430,6 @@
 #define	EOF	(-1)
 #define	IGN	(-2)
 #define	ESC	(1<<20)
-#define	GETC()	((--fi.c < 0)? filbuf(): (*fi.p++ & 0xff))
 
 enum
 {
@@ -756,7 +755,7 @@
 	if(s->macro) {
 		newio();
 		cp = ionext->b;
-		macexpand(s, cp, sizeof(ionext->b));
+		macexpand(s, cp, sizeof(ionext->b)-1);
 		pushio();
 		ionext->link = iostack;
 		iostack = ionext;
--- a/sys/src/cmd/cc/lexbody
+++ b/sys/src/cmd/cc/lexbody
@@ -238,7 +238,7 @@
 		if(s->macro) {
 			newio();
 			cp = ionext->b;
-			macexpand(s, cp, sizeof(ionext->b));
+			macexpand(s, cp, sizeof(ionext->b)-1);
 			pushio();
 			ionext->link = iostack;
 			iostack = ionext;
--- a/sys/src/cmd/cc/macbody
+++ b/sys/src/cmd/cc/macbody
@@ -350,7 +350,7 @@
 		}
 		base = allocn(base, len, 1);
 		base[len++] = c;
-		c = ((--fi.c < 0)? filbuf(): (*fi.p++ & 0xff));
+		c = GETC();
 		if(c == '\n')
 			lineno++;
 		if(c == -1) {
@@ -387,7 +387,10 @@
 	char *arg[NARG], *cp, *ob, *eb, *ecp, dots;
 
 	if(*s->macro == 0) {
+		b[blen-1] = 0;
 		strncpy(b, s->macro+1, blen);
+		if(b[blen-1] != '\0')
+			goto toobig;
 		if(debug['m'])
 			print("#expand %s %s\n", s->name, b);
 		return;
@@ -573,14 +576,13 @@
 	if(c != '\n')
 		goto bad;
 	f = -1;
-	c = 0;
 	for(i=0; i<ninclude; i++) {
 		if(i == 0 && c0 == '>')
 			continue;
-		c = snprint(symb, NSYMB, "%s/%s", include[i], str)+1;
-		if(strncmp(symb, "./", 2) == 0){
+		c = snprint(symb, NSYMB, "%s/%s", include[i], str);;
+		while(strncmp(symb, "./", 2) == 0){
 			c -= 2;
-			memmove(symb, symb+2, c);
+			memmove(symb, symb+2, c+1);
 		}
 		f = open(symb, 0);
 		if(f >= 0)
@@ -587,18 +589,10 @@
 			break;
 	}
 	if(f < 0)
-		c = snprint(symb, NSYMB, "%s", str)+1;
-	while(c & 3)
-		c++;
-	while(nhunk < c)
-		gethunk();
-	hp = hunk;
-	memmove(hunk, symb, c);
-	nhunk -= c;
-	hunk += c;
+		snprint(symb, NSYMB, "%s", str);
 	newio();
 	pushio();
-	newfile(hp, f);
+	newfile(strdup(symb), f);
 	return;
 
 bad: