Module Name: src
Committed By: kre
Date: Mon May 9 20:36:07 UTC 2016
Modified Files:
src/bin/sh: parser.c sh.1
Log Message:
PR bin/48489 -- Shell "simple commands" are now not allowed to be
completely empty, they must have something (var assignment, redirect,
or command, or multiple of those) to avoid a syntax error. This
matches the requirements of the grammar in the standard. Correct the
parser (using FreeBSD's sh as a guide) and update the man page to
remove text that noted a couple of places this was previously OK.
OK christos@
To generate a diff of this commit:
cvs rdiff -u -r1.118 -r1.119 src/bin/sh/parser.c
cvs rdiff -u -r1.121 -r1.122 src/bin/sh/sh.1
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/bin/sh/parser.c
diff -u src/bin/sh/parser.c:1.118 src/bin/sh/parser.c:1.119
--- src/bin/sh/parser.c:1.118 Tue May 3 03:16:55 2016
+++ src/bin/sh/parser.c Mon May 9 20:36:07 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: parser.c,v 1.118 2016/05/03 03:16:55 kre Exp $ */
+/* $NetBSD: parser.c,v 1.119 2016/05/09 20:36:07 kre Exp $ */
/*-
* Copyright (c) 1991, 1993
@@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)parser.c 8.7 (Berkeley) 5/16/95";
#else
-__RCSID("$NetBSD: parser.c,v 1.118 2016/05/03 03:16:55 kre Exp $");
+__RCSID("$NetBSD: parser.c,v 1.119 2016/05/09 20:36:07 kre Exp $");
#endif
#endif /* not lint */
@@ -498,20 +498,32 @@ TRACE(("expecting DO got %s %s\n", tokna
synexpect(TEND, 0);
checkkwd = 1;
break;
- /* Handle an empty command like other simple commands. */
+
case TSEMI:
- /*
- * An empty command before a ; doesn't make much sense, and
- * should certainly be disallowed in the case of `if ;'.
- */
- if (!redir)
- synexpect(-1, 0);
case TAND:
case TOR:
+ case TPIPE:
case TNL:
case TEOF:
- case TWORD:
case TRP:
+ /*
+ * simple commands must have something in them,
+ * either a word (which at this point includes a=b)
+ * or a redirection. If we reached the end of the
+ * command (which one of these tokens indicates)
+ * when we are just starting, and have not had a
+ * redirect, then ...
+ *
+ * nb: it is still possible to end up with empty
+ * simple commands, if the "command" is a var
+ * expansion that produces nothing
+ * X= ; $X && $X
+ * --> &&
+ * I am not sure if this is intended to be legal or not.
+ */
+ if (!redir)
+ synexpect(-1, 0);
+ case TWORD:
tokpushback++;
n1 = simplecmd(rpp, redir);
goto checkneg;
Index: src/bin/sh/sh.1
diff -u src/bin/sh/sh.1:1.121 src/bin/sh/sh.1:1.122
--- src/bin/sh/sh.1:1.121 Mon Apr 4 13:05:56 2016
+++ src/bin/sh/sh.1 Mon May 9 20:36:07 2016
@@ -1,4 +1,4 @@
-.\" $NetBSD: sh.1,v 1.121 2016/04/04 13:05:56 wiz Exp $
+.\" $NetBSD: sh.1,v 1.122 2016/05/09 20:36:07 kre Exp $
.\" Copyright (c) 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
@@ -31,7 +31,7 @@
.\"
.\" @(#)sh.1 8.6 (Berkeley) 5/4/95
.\"
-.Dd March 31, 2016
+.Dd May 9, 2016
.Dt SH 1
.ds flags abCEeFfhnuvxIimpqV
.Os
@@ -330,11 +330,9 @@ in which case altering the
flag has no effect.
.It Fl h Em trackall
Bind commands in functions to file system paths when the function is defined.
-.\" They can seek me here (that dreaded filesystem)
When off,
the file system is searched for commands each time the function is invoked.
(Not implemented.)
-.\" then can seek me there (the filesystem, once again)
.It Fl p Em nopriv
Do not attempt to reset effective uid if it does not match uid.
This is not set by default to help avoid incorrect usage by setuid
@@ -589,7 +587,6 @@ new process.
Otherwise, if the command name doesn't match a function or built-in, the
command is searched for as a normal program in the file system (as
described in the next section).
-.\" But the damned elusive filesystem shall never be defeated!
When a normal program is executed, the shell runs the program,
passing the arguments and the environment to the program.
If the program is not a normal executable file (i.e., if it does
@@ -757,14 +754,6 @@ writes
.Dq baz
and nothing else.
This is not the way it works in C.
-Also, if you forget the left-hand side (for example when continuing lines but
-forgetting to use a backslash) it defaults to a true statement.
-This behavior is not useful and should not be relied upon.
-Similarly, if input to the
-.Nm
-reaches end of file immediately after one of these operators,
-it is assumed that a true statement follows.
-This behavior is also not useful and should not be relied upon.
.Ss Flow-Control Constructs -- if, while, for, case
The syntax of the if command is
.Bd -literal -offset indent
