ash: fix a bug where redirection fds were not closed afterwards.

 optimize close+fcntl(DUPFD) into dup2. add testsuites.

function                                             old     new   delta
copyfd                                                47      68     +21
argstr                                              1311    1298     -13
popredir                                             148     131     -17
redirect                                            1139    1107     -32
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/3 up/down: 21/-62)            Total: -41 bytes

4 files changed, 14 insertions, 0 deletions

diff --git a/shell/ash_test/ash-redir/redir2.right b/shell/ash_test/ash-redir/redir2.right
new file mode 100644
index 000000000..d86bac9de
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir2.right
@@ -0,0 +1 @@
+OK
diff --git a/shell/ash_test/ash-redir/redir2.tests b/shell/ash_test/ash-redir/redir2.tests
new file mode 100755
index 000000000..61ccea30c
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir2.tests
@@ -0,0 +1,5 @@
+# ash once couldn't redirect above fd#9
+exec 1>/dev/null
+(echo LOST1 >&22) 22>&1
+(echo LOST2 >&22) 22>&1
+(echo OK >&22) 22>&2
diff --git a/shell/ash_test/ash-redir/redir3.right b/shell/ash_test/ash-redir/redir3.right
new file mode 100644
index 000000000..fd641a8ea
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir3.right
@@ -0,0 +1,3 @@
+TEST
+./redir3.tests: line 4: 9: Bad file descriptor
+Output to fd#9: 1
diff --git a/shell/ash_test/ash-redir/redir3.tests b/shell/ash_test/ash-redir/redir3.tests
new file mode 100755
index 000000000..f50a7674c
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir3.tests
@@ -0,0 +1,5 @@
+# redirects to closed descriptors should not leave these descriptors"
+# open afterwards
+echo TEST 9>/dev/null
+echo MUST ERROR OUT >&9
+echo "Output to fd#9: $?"