[address@hidden: glibc: select() buggy on Hurd]

[Michael Banck]

Hi,

Duck has sent in this bug report to the Debian BTS today, thought I'd
repost it here where more people might see it:

--- Begin Message --- Subject: glibc: select() buggy on Hurd Date: Sun, 20 Mar 2005 23:23:27 +0100 User-agent: Gnus/5.1007 (Gnus v5.10.7) Emacs/21.3 (gnu/linux)

Package: glibc
Version: 2.3.2.ds1-20


Coin,

Here is a simple poll() test case :
(hurd poll() directly uses hurd_select())
<quote file="poll.c">
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/poll.h>

int main(void)
{
        struct pollfd   pfd[1];
        int             fd, ret;
        char            c;

        fd = open("zzz", O_RDONLY);
        pfd[0].fd = fd;
        pfd[0].events = POLLIN;
        while ((ret = poll(pfd, 1, 10)) >= 0)
        {
                if (ret == 0)
                        continue;
                if (pfd[0].revents & POLLERR)
                        break;
                if (pfd[0].revents & POLLIN)
                {
                        printf("DATA !\n");
                        read(fd, &c, 1);
                }
        }

        return 0;
}
</quote>

Test :
mkfifo zzz
./poll &
echo "coin" >zzz


Result on linux :
DATA !
DATA !
DATA !
DATA !
DATA !

I've got 1 "DATA !" per character (including "\n").

Result on Hurd :
DATA !
DATA !
DATA !
DATA !
DATA !
DATA !
DATA !
[...]

I've got an infinite number of "DATA !".

It is like if the select state is not reset after reading.

I tried to find the bug but i need help, this software is not an easy peace.

Thanks.

-- 
Marc Dequènes (Duck)

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