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Date:      Mon, 9 Sep 2019 16:32:24 +0000 (UTC)
From:      Conrad Meyer <cem@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r352075 - head/sys/ddb
Message-ID:  <201909091632.x89GWOhK045835@repo.freebsd.org>
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Author: cem
Date: Mon Sep  9 16:32:23 2019
New Revision: 352075
URL: https://svnweb.freebsd.org/changeset/base/352075

Log:
  ddb(4): Add some support for lexing IPv6 addresses
  
  Allow commands to specify that (hex) numbers may start with A-F, by adding
  the DRT_HEX flag for db_read_token_flags().  As before, numbers containing
  invalid digits for the current radix are rejected.
  
  Also, lex ':' and '::' tokens as tCOLON and tCOLONCOLON respectively.
  
  There is a mild conflict here with lexed "identifiers" (tIDENT): ddb
  identifiers may contain arbitrary colons, and the ddb lexer is greedy.  So
  the identifier lex will swallow any colons it finds inside identifiers, and
  consumers are still unable to expect the token sequence 'tIDENT tCOLON'.
  That limitation does not matter for IPv6 addresses, because the lexer always
  attempts to lex numbers before identifiers.
  
  Reviewed by:	markj
  Differential Revision:	https://reviews.freebsd.org/D21509

Modified:
  head/sys/ddb/db_lex.c
  head/sys/ddb/db_lex.h

Modified: head/sys/ddb/db_lex.c
==============================================================================
--- head/sys/ddb/db_lex.c	Mon Sep  9 16:31:14 2019	(r352074)
+++ head/sys/ddb/db_lex.c	Mon Sep  9 16:32:23 2019	(r352075)
@@ -163,7 +163,7 @@ static int
 db_lex(int flags)
 {
 	int	c, n, radix_mode;
-	bool	lex_wspace;
+	bool	lex_wspace, lex_hex_numbers;
 
 	switch (flags & DRT_RADIX_MASK) {
 	case DRT_DEFAULT_RADIX:
@@ -181,6 +181,7 @@ db_lex(int flags)
 	}
 
 	lex_wspace = ((flags & DRT_WSPACE) != 0);
+	lex_hex_numbers = ((flags & DRT_HEX) != 0);
 
 	c = db_read_char();
 	for (n = 0; c <= ' ' || c > '~'; n++) {
@@ -193,13 +194,16 @@ db_lex(int flags)
 	    return (tWSPACE);
 	}
 
-	if (c >= '0' && c <= '9') {
+	if ((c >= '0' && c <= '9') ||
+	   (lex_hex_numbers &&
+	   ((c >= 'a' && c <= 'f') ||
+	   (c >= 'A' && c <= 'F')))) {
 	    /* number */
 	    int	r, digit = 0;
 
 	    if (radix_mode != -1)
 		r = radix_mode;
-	    else if (c > '0')
+	    else if (c != '0')
 		r = db_radix;
 	    else {
 		c = db_read_char();
@@ -328,6 +332,12 @@ db_lex(int flags)
 		}
 		db_unread_char(c);
 		return (tEXCL);
+	    case ':':
+		c = db_read_char();
+		if (c == ':')
+			return (tCOLONCOLON);
+		db_unread_char(c);
+		return (tCOLON);
 	    case ';':
 		return (tSEMI);
 	    case '&':

Modified: head/sys/ddb/db_lex.h
==============================================================================
--- head/sys/ddb/db_lex.h	Mon Sep  9 16:31:14 2019	(r352074)
+++ head/sys/ddb/db_lex.h	Mon Sep  9 16:32:23 2019	(r352075)
@@ -58,17 +58,26 @@ enum {
 /*
  * Flag bit powers of two for db_read_token_flags.
  * The low 2 bits are reserved for radix selection.
+ *
+ * WSPACE: Yield explicit tWSPACE tokens when one or more whitespace characters
+ *         is consumed.
+ * HEX:    Allow tNUMBER tokens to start with 'A'-'F' without explicit "0x"
+ *         prefix.
  */
 enum {
 	_DRT_WSPACE = 2,
+	_DRT_HEX,
 };
 #ifndef BIT
 #define	BIT(n)	(1ull << (n))
 #endif
 enum {
 	DRT_WSPACE = BIT(_DRT_WSPACE),
+	DRT_HEX = BIT(_DRT_HEX),
 };
-#define	DRT_VALID_FLAGS_MASK	((int)DRT_RADIX_MASK | DRT_WSPACE)
+#define	DRT_VALID_FLAGS_MASK	((int)DRT_RADIX_MASK | \
+    DRT_WSPACE | \
+    DRT_HEX)
 
 void	 db_flush_lex(void);
 char	*db_get_line(void);
@@ -123,5 +132,7 @@ extern char	db_tok_string[TOK_STRING_SIZE];
 #define	tQUESTION	33
 #define	tBIT_NOT	34
 #define	tWSPACE		35
+#define	tCOLON		36
+#define	tCOLONCOLON	37
 
 #endif /* !_DDB_DB_LEX_H_ */

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