Date: Wed, 28 Aug 2002 10:20:11 -0700 (PDT) From: Archie Cobbs <archie@packetdesign.com> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/42100: libc_r: accept(2) can't handle descriptor being closed/shutdown Message-ID: <200208281720.g7SHKBo7015655@freefall.freebsd.org>
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The following reply was made to PR bin/42100; it has been noted by GNATS.
From: Archie Cobbs <archie@packetdesign.com>
To: Daniel Eischen <eischen@pcnet1.pcnet.com>
Cc:
Subject: Re: bin/42100: libc_r: accept(2) can't handle descriptor being closed/shutdown
Date: Wed, 28 Aug 2002 09:54:44 -0700
Daniel Eischen wrote:
> I hacked up your program a bit and it looks like the kernel
Hang on.. I want to make sure I fully understand what you're saying.
If it's the kernel's fault, then libc_r should have nothing to do
with it, right? So I wrote another test program (below) and compiled
it *without* -pthread..
There are four cases: shutdown() vs. close() and FreeBSD vs. Linux.
Here is what accept() returns in these four cases:
shutdown() | close()
----------------+--------------
FreeBSD EAGAIN | EBADF
Linux EINVAL | EBADF
So there are two conclusions:
1. FreeBSD returns EAGAIN for a file descriptor that has been
shutdown(). This is at best inconsistent with Linux, but
is probably plain wrong because EAGAIN has a special meaning
for O_NONBLOCK file descriptors.
2. The kernel is behaving properly in the close() case, which
contradicts your claim that a kernel problem is responsible
for the bug in the original test program in the close() case.
-Archie
__________________________________________________________________________
Archie Cobbs * Packet Design * http://www.packetdesign.com
============================= CUT HERE ===============================
/* Compile as: cc -o xx -Wall xx.c */
#ifdef __linux__
#define _XOPEN_SOURCE 600
#define _GNU_SOURCE 1
#define _BSD_SOURCE 1
#define _ISOC99_SOURCE 1
#endif
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <err.h>
#define USE_SHUTDOWN 1
int
main(int ac, char **av)
{
struct sockaddr_in sin;
socklen_t slen;
int sock;
/* Create socket */
if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1)
err(1, "socket");
memset(&sin, 0, sizeof(sin));
#ifndef __linux__
sin.sin_len = sizeof(sin);
#endif
sin.sin_family = AF_INET;
if (bind(sock, (struct sockaddr *)&sin, sizeof(sin)) == -1)
err(1, "socket");
/* Set socket to non-blocking */
if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1)
err(1, "fcntl");
/* Listen for connections on socket */
if (listen(sock, 10) == -1)
err(1, "listen");
slen = sizeof(sin);
printf("created socket\n");
#if USE_SHUTDOWN
/* Shutdown socket */
printf("calling shutdown()\n");
if (shutdown(sock, SHUT_RDWR) == -1)
err(1, "shutdown");
#else
/* Close socket */
printf("calling close()\n");
if (close(sock) == -1)
err(1, "close");
#endif
/* Try to accept on socket */
printf("calling accept()\n");
if (accept(sock, (struct sockaddr *)&sin, &slen) == -1)
err(1, "accept");
printf("got connection?\n");
return (0);
}
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