tee: fix a crash with unwriteable files

This was introduced recently with commit v9.1-166-g6b12e62d9

* src/tee.c (tee_files): Check the return from fopen()
before passing to fileno() etc.
* tests/misc/tee.sh: Add a test case.

1 files changed, 5 insertions, 0 deletions

diff --git a/tests/misc/tee.sh b/tests/misc/tee.sh
index 30d64a9d2..63e7524c0 100755
--- a/tests/misc/tee.sh
+++ b/tests/misc/tee.sh
@@ -74,6 +74,11 @@ retry_delay_ tee_exited .1 7 | # 12.7s (Must be > following timeout)
 test $(wc -l < err) = 0 || { cat err; fail=1; }
 test -f tee.exited || fail=1
 
+# Test with unwriteable files
+touch file.ro || framework_failure_
+chmod a-w file.ro || framework_failure_
+returns_ 1 tee -p </dev/null file.ro || fail=1
+
 # Ensure tee honors --output-error modes
 mkfifo_or_skip_ fifo
 read_fifo() { timeout 10 dd count=1 if=fifo of=/dev/null status=none & }