ash: fix corruption of ${#var} if $var contains UTF-8 characters

As reported in bug 8506:

   $ X=abcdÉfghÍjklmnÓpqrstÚvwcyz
   $ echo ${#X}
   abcd26

The result should be 26.

This regression was introduced by:

   <d68d1fb> 2015-05-18 [Ron Yorston]  ash: code shrink around varvalue

The length in characters was being used to discard the contents of
the variable instead of the length in bytes.

URL: https://bugs.busybox.net/8506
Reported-by: Martijn Dekker <martijn@inlv.org>
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
(cherry picked from commit 3e3bfb896e0dd8a54caad9c6264e2452566b4012)

diff --git a/shell/ash.c b/shell/ash.c
index 256e933e32e250464d88d41b4188c11c2204344c..96aa2a223d34e4de2a7f5f20d339246e3ab44404 100644 (file)
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -6693,6 +6693,8 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
                if (subtype == VSLENGTH && len > 0) {
                        reinit_unicode_for_ash();
                        if (unicode_status == UNICODE_ON) {
+                               STADJUST(-len, expdest);
+                               discard = 0;
                                len = unicode_strlen(p);
                        }
                }

diff --git a/shell/ash_test/ash-vars/var-utf8-length.right b/shell/ash_test/ash-vars/var-utf8-length.right
new file mode 100644 (file)
index 0000000..6f4247a
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-utf8-length.right
@@ -0,0 +1 @@
+26

diff --git a/shell/ash_test/ash-vars/var-utf8-length.tests b/shell/ash_test/ash-vars/var-utf8-length.tests
new file mode 100755 (executable)
index 0000000..d04b2cb
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-utf8-length.tests
@@ -0,0 +1,2 @@
+X=abcdÉfghÍjklmnÓpqrstÚvwcyz
+echo ${#X}