How to terminate a process on SIGPIPE?

Question

I have a server program that uses IPv4. The server has to attend multiple calls from client, so it creates a child process every time it accepts a client socket connection to deal with the client.

The child process is expected to read from client and then write to client socket. If it receives a SIGPIPE (from a bad client that closes before writing), it should terminate as the child's job is done. Do I explicitly declare a signal handler or does SIGPIPE terminate it by default? I am a beginner so please accept my ignorance if any.

The default handler for SIGPIPE terminates the process. – Barmar Aug 11 '21 at 22:45 — Barmar, Aug 11 '21 at 22:45
So, you _want_ the server process to terminate on SIGPIPE? – Ted Lyngmo Aug 11 '21 at 22:50 — Ted Lyngmo, Aug 11 '21 at 22:50
@TedLyngmo no just the child that deals with a bad client. – Kenpachi Zaraki Aug 11 '21 at 22:54 — Kenpachi Zaraki, Aug 11 '21 at 22:54

Marco Bonelli · Accepted Answer · 2021-08-11T23:08:47.440

0

From man 7 signal:

The entries in the "Action" column of the table below specify the default
disposition for each signal, as follows:

    Term   Default action is to terminate the process.
    [...]

Then, later on in the table:

Signal      Standard   Action   Comment
────────────────────────────────────────────────────────────────────────
[...]
SIGPIPE      P1990      Term    Broken pipe: write to pipe with no
                                readers; see pipe(7)

So you don't need to do anything, the default signal handler will terminate the process.

edited Aug 11 '21 at 23:08

answered Aug 11 '21 at 22:47

Marco Bonelli

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That helped a lot. Also when SIGPIPE was encountered by one of the children, it would only kill that specific child and not the parent server right? Because the parent must continue replying to its other client children. – Kenpachi Zaraki Aug 11 '21 at 22:53
That's how all signals work. They just get sent to that process, not the parent. – Barmar Aug 11 '21 at 22:57
@KenpachiZaraki yes. – Marco Bonelli Aug 11 '21 at 22:58

How to terminate a process on SIGPIPE?

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