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Date: Sat, 18 Nov 1995 20:23:52 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199511180923.UAA17204@godzilla.zeta.org.au>
To: bde@zeta.org.au, grog@lemis.de
Subject: Re: linux' mknod and named pipes.
Cc: hackers@freebsd.org
Sender: owner-hackers@freebsd.org
Precedence: bulk

>> >Is there any good reason why we shouldn't modify mknod to make a fifo
>> >when called with the appropriate parameters?
>> 
>> The same reason we shouldn't modify thousands of other system calls to be
>> compatible with thousands of other systems: it takes longer and gives
>> worse results.

>I think that bears discussion.

>1.  It takes longer:

>--- vfs_syscalls.c      1995/11/14 09:19:16     1.40
>+++ vfs_syscalls.c      1995/11/18 08:45:43
>@@ -757,6 +757,13 @@
>        int error;
>        struct nameidata nd;
> 
>+       if (ISFIFO (uap->mode))
>+         {
>+         struct mkfifo_args args;
>+         args.path = uap->path;
>+         args.mode = uap->mode;
>+         return mkfifo (p, args);
>+         }
>        error = suser(p->p_ucred, &p->p_acflag);
>        if (error)
>                return (error);

>    OK, I haven't tested this, but it's got to be something like it.
>    In the normal case, there's a single 'if' involved.

It takes longer to write, document, commit and test.  Perhaps even as
long as to argue about it :-).

>2.  It gives worse results.  How?  Why?

It just confuses programmers to have two ways of doing the same thing.

The p flag to mknod(8) isn't supported either.

Bruce