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sigpipe #11

Closed CyprienRicque closed 2 years ago

CyprienRicque commented 5 years ago

ls | exit ; ls : sigpipe but ls | exit : don't sigpipe

mepholic commented 5 years ago

Pretty sure this is not an actual bug. As per the POSIX specification, I believe this is expected behavior:

A SIGPIPE signal is raised if a thread sends on a broken stream (one that is no longer connected). ... The SIGPIPE signal shall be sent to a thread that attempts to send data on a socket that is no longer able to send. In addition, the send operation fails with the error [EPIPE]. _http://pubs.opengroup.org/onlinepubs/007904875/functions/xsh_chap02_10.html_

Also, translated from the 1st table in another piece of reference documentation:

Signal: SIGPIPE Default Action: Abnormal termination of the process. Description: Write on a pipe with no one to read it. http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/signal.h.html

Without digging into the code at all, I'd guess that exiting the shell immediately releases the tty, thereby closing STDOUT before ls tries to write to it, which would very correctly result in a SIGPIPE according to specification.

For more info on when write() returns an EPIPE/SIGPIPE, please refer to the reference documentation here: https://pubs.opengroup.org/onlinepubs/009695399/functions/write.html

suominen commented 2 years ago

I'm not sure what is expected in this ticket. Can you clarify?

zoulasc commented 2 years ago

pipes to and from builtins are kind of broken. see https://bugs.astron.com/view.php?id=153

suominen commented 2 years ago

Closing in preference of tracking this in the more general ticket linked above.