Hi, I'm forwarding a bug report originally reported in
<https://bugs.debian.org/822605>.
When a builtin function like echo fails to write to a named pipe, bash
will receive a SIGPIPE that will terminate the whole shell.
To reproduce this issue:
In shell 1:
$ rm -f /tmp/f && mkfifo /tmp/f && \
(i=0; while true; do echo $((i=i+1)) > /tmp/f; done); \
echo "terminated with exit status $?"
In shell 2:
$ while true; do echo $(< /tmp/f); done
The command in the first shell will exit after a random number of
iterations with "terminated with exit status 141".
The reason for the SIGPIPE is a race condition illustrated in [1].
Regardless of the reason for the SIGPIPE, the reporter expects the loop
to carry on indefinitely (`while true; ...`).
One possible solution suggested in [1] is:
it is incorrect that > SIGPIPE terminates the subshell.
When bash runs a builtin command without forking, it should install
a SIGPIPE handler that will cause that signal to abort the command
but not terminate the shell.
If this behavior is desired and not considered a bug, then the bash
manual should describe it in the SIGNALS section.
Regards,
[1] https://bugs.debian.org/822605#26
--
Gioele Barabucci
