Date: Wed, 22 May 1996 15:02:14 +0200 (MET DST) From: Kees Jan Koster <dutchman@spase.nl> To: freebsd-hackers@FreeBSD.ORG (FreeBSD hackers Mailing list) Subject: Forgiving select() call. Message-ID: <199605221302.PAA00484@phobos.spase.nl>
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Hoi Hackers,
Consider the following excerpt from /sys/kern/sys_generic.c, from
2.1.0-release. Somewhere near line 550. This piece of code forgives
programs that specify a too large `nd' value by setting it to a more
acceptable value.
...
if (uap->nd > p->p_fd->fd_nfiles)
uap->nd = p->p_fd->fd_nfiles; /* forgiving; slightly wrong */
...
Out of curiosity I printed the process ID's of processes that were
forgiven in this way. One of the biggest offenders was the X server %-).
My questions:
- shouldn't programs that are forgiven be patched to specify correct
values?
- If I were to hack my kernel to return EINVAL instead, would that be
a correct (if pedantic) thing to do?
- I noticed that EINVAL is also returned if (uap->nd > FD_SETSIZE), why
is that not forgiven. Why does the select(2) manual page not mention
this.
I want to modify select(2) to return the `timeout left' as described in the
BUGS section of the manual page. Any reason why I should not?
I have only the 2.1.0-release source tree. Has select() been modified a
lot since then?
Groetjes,
Kees Jan
======================================================================v==
Kees Jan Koster e-mail: dutchman@spase.nl
Van Somerenstraat 50 tel: NL-24-3234708
6521 BS Nijmegen
the Netherlands
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Who is this general Failure and why is he reading my disk? (anonymous)
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