svn commit: r231578 - stable/9/usr.bin/hexdump

[Tijl Coosemans]

Author: tijl
Date: Mon Feb 13 10:24:49 2012
New Revision: 231578
URL: http://svn.freebsd.org/changeset/base/231578

Log:
  MFC r229794:
  
  - Fix how hexdump parses escape strings
  From the NetBSD bug:
  The way how hexdump(1) parses escape sequences has some bugs.
  It shows up when an escape sequence is used as the non-last character
  of a format string.
  
  MFC r230649:
  
  Fix decoding of escape sequences in format strings:
  - Zero-terminate the resulting string by letting the for-loop copy the
    terminating zero.
  - Exit the for-loop after handling a backslash at the end of the format
    string to fix a buffer overrun.
  - Remove some unnecessary comments and blank lines.
  
  PR:		bin/144722

Modified:
  stable/9/usr.bin/hexdump/parse.c
Directory Properties:
  stable/9/usr.bin/hexdump/   (props changed)

Modified: stable/9/usr.bin/hexdump/parse.c
==============================================================================
--- stable/9/usr.bin/hexdump/parse.c	Mon Feb 13 10:24:22 2012	(r231577)
+++ stable/9/usr.bin/hexdump/parse.c	Mon Feb 13 10:24:49 2012	(r231578)
@@ -255,7 +255,9 @@ rewrite(FS *fs)
 					sokay = NOTOKAY;
 			}
 
-			p2 = p1 + 1;		/* Set end pointer. */
+			p2 = *p1 ? p1 + 1 : p1;	/* Set end pointer -- make sure
+						 * that it's non-NUL/-NULL first
+						 * though. */
 			cs[0] = *p1;		/* Set conversion string. */
 			cs[1] = '\0';
 
@@ -449,13 +451,14 @@ escape(char *p1)
 	char *p2;
 
 	/* alphabetic escape sequences have to be done in place */
-	for (p2 = p1;; ++p1, ++p2) {
-		if (!*p1) {
-			*p2 = *p1;
-			break;
-		}
-		if (*p1 == '\\')
-			switch(*++p1) {
+	for (p2 = p1;; p1++, p2++) {
+		if (*p1 == '\\') {
+			p1++;
+			switch(*p1) {
+			case '\0':
+				*p2 = '\\';
+				*++p2 = '\0';
+				return;
 			case 'a':
 			     /* *p2 = '\a'; */
 				*p2 = '\007';
@@ -482,6 +485,11 @@ escape(char *p1)
 				*p2 = *p1;
 				break;
 			}
+		} else {
+			*p2 = *p1;
+			if (*p1 == '\0')
+				return;
+		}
 	}
 }