From: deraadt <deraadt@openbsd.org>
Date: Wed, 4 May 2022 18:57:50 +0000 (+0000)
Subject: Found two multiple evaluation macros. One of them so long and scary it
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=93060a2b6ebc0fa8a5115dfb157dfafc29e9ca63;p=openbsd

Found two multiple evaluation macros. One of them so long and scary it
too many people to unravel correctly and place into a static function.
While here, move the flags bits into local variables, which reduces
the amount of () in the checks.
help from millert, miod, tedu
---

diff --git a/lib/libc/gen/vis.c b/lib/libc/gen/vis.c
index 4400c7bf1ca..6f7b501f847 100644
--- a/lib/libc/gen/vis.c
+++ b/lib/libc/gen/vis.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vis.c,v 1.25 2015/09/13 11:32:51 guenther Exp $ */
+/*	$OpenBSD: vis.c,v 1.26 2022/05/04 18:57:50 deraadt Exp $ */
 /*-
  * Copyright (c) 1989, 1993
  *	The Regents of the University of California.  All rights reserved.
@@ -36,18 +36,41 @@
 #include <stdlib.h>
 #include <vis.h>
 
-#define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
-#define	isvisible(c,flag)						\
-	(((c) == '\\' || (flag & VIS_ALL) == 0) &&			\
-	(((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&		\
-	(((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||	\
-		(flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||	\
-	((flag & VIS_SP) == 0 && (c) == ' ') ||				\
-	((flag & VIS_TAB) == 0 && (c) == '\t') ||			\
-	((flag & VIS_NL) == 0 && (c) == '\n') ||			\
-	((flag & VIS_SAFE) && ((c) == '\b' ||				\
-		(c) == '\007' || (c) == '\r' ||				\
-		isgraph((u_char)(c))))))
+static int
+isoctal(int c)
+{
+	u_char uc = c;
+
+	return uc >= '0' && uc <= '7';
+}
+
+static int
+isvisible(int c, int flag)
+{
+	int vis_sp = flag & VIS_SP;
+	int vis_tab = flag & VIS_TAB;
+	int vis_nl = flag & VIS_NL;
+	int vis_safe = flag & VIS_SAFE;
+	int vis_glob = flag & VIS_GLOB;
+	int vis_all = flag & VIS_ALL;
+	u_char uc = c;
+
+	if (c == '\\' || !vis_all) {
+		if ((u_int)c <= UCHAR_MAX && isascii(uc) &&
+		    ((c != '*' && c != '?' && c != '[' && c != '#') || !vis_glob) &&
+		    isgraph(uc))
+			return 1;
+		if (!vis_sp && c == ' ')
+			return 1;
+		if (!vis_tab && c == '\t')
+			return 1;
+		if (!vis_nl && c == '\n')
+			return 1;
+		if (vis_safe && (c == '\b' || c == '\007' || c == '\r' || isgraph(uc)))
+			return 1;
+	}
+	return 0;
+}
 
 /*
  * vis - visually encode characters
@@ -55,17 +78,23 @@
 char *
 vis(char *dst, int c, int flag, int nextc)
 {
+	int vis_dq = flag & VIS_DQ;
+	int vis_noslash = flag & VIS_NOSLASH;
+	int vis_cstyle = flag & VIS_CSTYLE;
+	int vis_octal = flag & VIS_OCTAL;
+	int vis_glob = flag & VIS_GLOB;
+
 	if (isvisible(c, flag)) {
-		if ((c == '"' && (flag & VIS_DQ) != 0) ||
-		    (c == '\\' && (flag & VIS_NOSLASH) == 0))
+		if ((c == '"' && vis_dq) ||
+		    (c == '\\' && !vis_noslash))
 			*dst++ = '\\';
 		*dst++ = c;
 		*dst = '\0';
 		return (dst);
 	}
 
-	if (flag & VIS_CSTYLE) {
-		switch(c) {
+	if (vis_cstyle) {
+		switch (c) {
 		case '\n':
 			*dst++ = '\\';
 			*dst++ = 'n';
@@ -108,15 +137,15 @@ vis(char *dst, int c, int flag, int nextc)
 			goto done;
 		}
 	}
-	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
-	    ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
+	if (((c & 0177) == ' ') || vis_octal ||
+	    (vis_glob && (c == '*' || c == '?' || c == '[' || c == '#'))) {
 		*dst++ = '\\';
 		*dst++ = ((u_char)c >> 6 & 07) + '0';
 		*dst++ = ((u_char)c >> 3 & 07) + '0';
 		*dst++ = ((u_char)c & 07) + '0';
 		goto done;
 	}
-	if ((flag & VIS_NOSLASH) == 0)
+	if (!vis_noslash)
 		*dst++ = '\\';
 	if (c & 0200) {
 		c &= 0177;
@@ -167,6 +196,8 @@ DEF_WEAK(strvis);
 int
 strnvis(char *dst, const char *src, size_t siz, int flag)
 {
+	int vis_dq = flag & VIS_DQ;
+	int vis_noslash = flag & VIS_NOSLASH;
 	char *start, *end;
 	char tbuf[5];
 	int c, i;
@@ -174,8 +205,8 @@ strnvis(char *dst, const char *src, size_t siz, int flag)
 	i = 0;
 	for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
 		if (isvisible(c, flag)) {
-			if ((c == '"' && (flag & VIS_DQ) != 0) ||
-			    (c == '\\' && (flag & VIS_NOSLASH) == 0)) {
+			if ((c == '"' && vis_dq) ||
+			    (c == '\\' && !vis_noslash)) {
 				/* need space for the extra '\\' */
 				if (dst + 1 >= end) {
 					i = 2;