On 08/11/16 16:39, Julian Büning wrote: > We observed another behavior possibly related to bug #24495:
Similar yes. > $ mkdir foo > $ echo "bar" | tail -f - foo & > [1] 16386 > ==> standard input <== > bar > > ==> foo <== > tail: error reading 'foo': Is a directory > tail: foo: cannot follow end of this type of file; giving up on this name > $ jobs > [1]+ Running echo "bar" | tail -f - foo & Yes we should exit here. > $ readlink /proc/16386/fd/0 > pipe:[162156] > $ lsof | grep 162156 > tail 16386 user 0r FIFO 0,10 0t0 > 162156 pipe > > Only the reading end of the pipe is still open, thus tail should not be > able to read any more bytes from it. Right we're not blocked on read() The attached should fix it up. thanks, Pádraig. p.s. These Symbolic Execution techniques are intriguing. Have you any more details.
From a6207bdacee615ad6e19e24911aad7ae8364f6f9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]> 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
