From a6207bdacee615ad6e19e24911aad7ae8364f6f9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <address@hidden>
Date: Tue, 8 Nov 2016 17:34:44 +0000
Subject: [PATCH] tail: terminate when following pipes and untailable non pipes

* src/tail.c (ignore_pipe_or_fifo): Mark the descriptor as -1
for pipes so that any_live_files() detects correctly that
the entry is no longer live.
* tests/tail-2/pipe-f.sh: Add a test case.
Fixes http://bugs.gnu.org/24903 which was detected
using Symbolic Execution techniques developed in
the course of the SYMBIOSYS research project at
COMSYS, RWTH Aachen University.
---
 src/tail.c             |  5 ++++-
 tests/tail-2/pipe-f.sh | 11 ++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/tail.c b/src/tail.c
index 718fc8a..96982ed 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -2212,7 +2212,10 @@ ignore_fifo_and_pipe (struct File_spec *f, size_t n_files)
          && (S_ISFIFO (f[i].mode)
              || (HAVE_FIFO_PIPES != 1 && isapipe (f[i].fd))));
       if (is_a_fifo_or_pipe)
-        f[i].ignore = true;
+        {
+          f[i].fd = -1;
+          f[i].ignore = true;
+        }
       else
         ++n_viable;
     }
diff --git a/tests/tail-2/pipe-f.sh b/tests/tail-2/pipe-f.sh
index 7abb7d6..82364da 100755
--- a/tests/tail-2/pipe-f.sh
+++ b/tests/tail-2/pipe-f.sh
@@ -19,9 +19,18 @@
 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
 print_ver_ tail
 
+echo oo > exp || framework_failure_
 echo foo | timeout 10 tail -f -c3 > out || fail=1
-echo oo > exp || fail=1
+compare exp out || fail=1
+
+cat <<\EOF > exp
+==> standard input <==
+ar
 
+==> missing <==
+EOF
+mkdir missing || framework_failure_
+echo bar | returns_ 1 timeout 10 tail -f -c3 - missing > out || fail=1
 compare exp out || fail=1
 
 Exit $fail
-- 
2.5.5