svn commit: r315005 - in head/bin/sh: . tests/expansion

[Jilles Tjoelker]

Author: jilles
Date: Fri Mar 10 16:04:00 2017
New Revision: 315005
URL: https://svnweb.freebsd.org/changeset/base/315005

Log:
  sh: Fix executing wrong command with ${unsetvar#$(cmdsubst)}$(cmdsubst).
  
  The parsed internal representation of words consists of a byte string with a
  list of nodes (commands in command substitution). Each unescaped CTLBACKQ or
  CTLBACKQ | CTLQUOTE byte corresponds to an entry in the list.
  
  If param in ${param#%##%%word} is not set, the word is not expanded (in a
  deviation of POSIX shared with other ash variants and ksh93). Erroneously,
  the pointer in the list of commands (argbackq) was not advanced. This caused
  the wrong command to be executed later if the outer word contained another
  command substitution.
  
  Example:
    echo "${unsetvar#$(echo a)}$(echo b)"
  wrote "a" but should write "b".
  
  MFC after:	1 week

Added:
  head/bin/sh/tests/expansion/cmdsubst23.0   (contents, props changed)
Modified:
  head/bin/sh/expand.c
  head/bin/sh/tests/expansion/Makefile

Modified: head/bin/sh/expand.c
==============================================================================
--- head/bin/sh/expand.c	Fri Mar 10 14:44:59 2017	(r315004)
+++ head/bin/sh/expand.c	Fri Mar 10 16:04:00 2017	(r315005)
@@ -769,8 +769,10 @@ again: /* jump here after setting a vari
 	case VSTRIMLEFTMAX:
 	case VSTRIMRIGHT:
 	case VSTRIMRIGHTMAX:
-		if (!set)
+		if (!set) {
+			set = 1;
 			break;
+		}
 		/*
 		 * Terminate the string and start recording the pattern
 		 * right after it

Modified: head/bin/sh/tests/expansion/Makefile
==============================================================================
--- head/bin/sh/tests/expansion/Makefile	Fri Mar 10 14:44:59 2017	(r315004)
+++ head/bin/sh/tests/expansion/Makefile	Fri Mar 10 16:04:00 2017	(r315005)
@@ -44,6 +44,7 @@ ${PACKAGE}FILES+=	cmdsubst19.0
 ${PACKAGE}FILES+=	cmdsubst20.0
 ${PACKAGE}FILES+=	cmdsubst21.0
 ${PACKAGE}FILES+=	cmdsubst22.0
+${PACKAGE}FILES+=	cmdsubst23.0
 ${PACKAGE}FILES+=	export1.0
 ${PACKAGE}FILES+=	export2.0
 ${PACKAGE}FILES+=	export3.0

Added: head/bin/sh/tests/expansion/cmdsubst23.0
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ head/bin/sh/tests/expansion/cmdsubst23.0	Fri Mar 10 16:04:00 2017	(r315005)
@@ -0,0 +1,5 @@
+# $FreeBSD$
+
+unset n
+x=abcd
+[ "X${n#$(echo a)}X${x#$(echo ab)}X$(echo abc)X" = XXcdXabcX ]