Date: 12 May 2001 16:34:36 -0000 From: clemens fischer <ino-waiting@gmx.net> To: FreeBSD-gnats-submit@freebsd.org Subject: kern/27287: poll(2) returns 0 when POLLIN-ing ordinary files Message-ID: <20010512163436.3789.qmail@spotteswoode.yi.org>
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>Number: 27287
>Category: kern
>Synopsis: poll(2) returns 0 when POLLIN-ing ordinary files
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sat May 12 09:40:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator: Super
>Release: FreeBSD 4.0-RELEASE i386
>Organization:
privat
>Environment:
the bug is in freebsd 4 and can be verified using the follwing code snipet.
>Description:
given a file "trypoll.c" (for relevant lines see below), poll does not see
that input is ready immediately. the following code-snipet returns 0 for
the return value and also 0 in x.revents.
x.fd = open("trypoll.c",O_RDONLY);
if (x.fd == -1) _exit(111);
x.events = POLLIN;
if (poll(&x,1,10) == -1) _exit(1);
if (x.revents != POLLIN) _exit(1);
>How-To-Repeat:
see above.
>Fix:
there is a workaround for poll(2) based on select(2). it is contained in
iopoll.c of the package cvm-0.6 (Credential Verification Module) by bruce
guenther.
>Release-Note:
>Audit-Trail:
>Unformatted:
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