Do not allow NUL bytes in string literals or character constants.

diff --git a/ChangeLog b/ChangeLog
index 1461692500df3ad99c7ae36fd077751c745317f4..446bafe540c7826fd31ca1b2147c50dd8bdec763 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2003-10-07  Paul Eggert  <eggert@twinsun.com>
+
+       * doc/bison.texinfo (Symbols): NUL bytes are not allowed in string
+       literals, unfortunately.
+       * src/scan-gram.l (<SC_ESCAPED_STRING,SC_ESCAPED_CHARACTER>):
+       Complain about NUL bytes in character constants or string literals.
+
 2003-10-05  Paul Eggert  <eggert@twinsun.com>
 
        * NEWS: Don't document %no-default-prec, as it's still

diff --git a/doc/bison.texinfo b/doc/bison.texinfo
index c7e1b6338ae9f544bffb0a56e16daab31e0ef12e..c1bff43ca1f832211d171865c608cd62dcc16215 100644 (file)
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -2481,7 +2481,8 @@ does not enforce this convention, but if you depart from it, people who
 read your program will be confused.
 
 All the escape sequences used in string literals in C can be used in
-Bison as well.  However, unlike Standard C, trigraphs have no special
+Bison as well, except that you must not use a null character within a
+string literal.  Also, unlike Standard C, trigraphs have no special
 meaning in Bison string literals, nor is backslash-newline allowed.  A
 literal string token must contain two or more characters; for a token
 containing just one character, use a character token (see above).

diff --git a/src/scan-gram.l b/src/scan-gram.l
index 5cbacfc13e1b05004338e4784b785a0075d0706e..742d54e82cf9567ddf15bb1aacbd454d49af9c3c 100644 (file)
--- a/src/scan-gram.l
+++ b/src/scan-gram.l
@@ -371,6 +371,7 @@ splice       (\\[ \f\t\v]*\n)*
     return STRING;
   }
 
+  \0       complain_at (*loc, _("invalid null character"));
   .|\n     STRING_GROW;
   <<EOF>>   unexpected_eof (token_start, "\""); BEGIN INITIAL;
 }
@@ -397,6 +398,7 @@ splice       (\\[ \f\t\v]*\n)*
     return ID;
   }
 
+  \0       complain_at (*loc, _("invalid null character"));
   .|\n     STRING_GROW;
   <<EOF>>   unexpected_eof (token_start, "'"); BEGIN INITIAL;
 }
@@ -412,6 +414,8 @@ splice       (\\[ \f\t\v]*\n)*
     unsigned long c = strtoul (yytext + 1, 0, 8);
     if (UCHAR_MAX < c)
       complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
+    else if (! c) 
+      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
     else
       obstack_1grow (&obstack_for_string, c);
   }
@@ -422,6 +426,8 @@ splice       (\\[ \f\t\v]*\n)*
     c = strtoul (yytext + 2, 0, 16);
     if (UCHAR_MAX < c || get_errno ())
       complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
+    else if (! c)
+      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
     else
       obstack_1grow (&obstack_for_string, c);
   }
@@ -441,6 +447,8 @@ splice       (\\[ \f\t\v]*\n)*
     int c = convert_ucn_to_byte (yytext);
     if (c < 0)
       complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
+    else if (! c)
+      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
     else
       obstack_1grow (&obstack_for_string, c);
   }