[PATCH] Close job control fd before running tests.

[Eric Blake]

* doc/autoconf.texi (File Descriptors): Clarify limitations.
* lib/autotest/general.m4 (AT_CLEANUP): Avoid leaking job control
fifo fd to user tests.
(AT_INIT): Delete comment, now that close is done elsewhere.
Suggested by Ralf Wildenhues.

Signed-off-by: Eric Blake <address@hidden>
---

This should be pretty safe.

 ChangeLog               |    9 +++++++++
 doc/autoconf.texi       |    8 +++++++-
 lib/autotest/general.m4 |    4 ++--
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e9146c3..2544b76 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2010-07-20  Eric Blake  <address@hidden>
+
+       Close job control fd before running tests.
+       * doc/autoconf.texi (File Descriptors): Clarify limitations.
+       * lib/autotest/general.m4 (AT_CLEANUP): Avoid leaking job control
+       fifo fd to user tests.
+       (AT_INIT): Delete comment, now that close is done elsewhere.
+       Suggested by Ralf Wildenhues.
+
 2010-07-20 Paul Eggert  <address@hidden>
        and Eric Blake  <address@hidden>

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index c47d510..c3a8714 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -15006,7 +15006,7 @@ File Descriptors
 Within the process which runs the @samp{descrips} script, file
 descriptor 5 is closed.

-Don't rely on redirection to a closed file descriptor to cause an
+Don't rely on duplicating a closed file descriptor to cause an
 error.  With Solaris @command{/bin/sh}, when the redirection fails, the
 output goes to the original file descriptor.

@@ -15019,6 +15019,12 @@ File Descriptors
 0
 @end example

+Fortunately, an attempt to close an already closed file descriptor will
+portably succeed.  Likewise, it is safe to use either style of
address@hidden@var{n}<&-} or @address@hidden>&-} for closing a file descriptor,
+even if it doesn't match the read/write mode that the file descriptor
+was opened with.
+
 DOS variants cannot rename or remove open files, such as in
 @samp{mv foo bar >foo} or @samp{rm foo >foo}, even though this is
 perfectly portable among Posix hosts.
diff --git a/lib/autotest/general.m4 b/lib/autotest/general.m4
index f328ef4..4acdb9d 100644
--- a/lib/autotest/general.m4
+++ b/lib/autotest/general.m4
@@ -1405,7 +1405,7 @@ dnl           kill -13 $$
       at_fn_group_prepare
       if cd "$at_group_dir" &&
         at_fn_test $at_group &&
-        . "$at_test_source" [#] AT_JOB_FIFO_OUT_FD>&-
+        . "$at_test_source"
       then :; else
        AS_WARN([unable to parse test group: $at_group])
        at_failed=:
@@ -1917,7 +1917,7 @@ echo "#                             -*- compilation -*-" 
>> "$at_group_log"
 m4_undivert([TEST_SCRIPT])dnl Insert the code here
   set +x
   $at_times_p && times >"$at_times_file"
-) AS_MESSAGE_LOG_FD>&1 2>&1 | eval $at_tee_pipe
+) AS_MESSAGE_LOG_FD>&1 2>&1 AT_JOB_FIFO_OUT_FD>&- | eval $at_tee_pipe
 read at_status <"$at_status_file"
 [#AT_STOP_]AT_ordinal
 m4_divert_pop([TEST_GROUPS])dnl Back to KILL.
-- 
1.7.1.1