| xhoster@gmail.com 2006-10-30, 9:58 pm |
| "Athanasios" <aduitsis@gmail.com> wrote:
> Hi everyone,
>
> I am trying to open the /dev/net/tun character device with perl.
>
> In C, I would issue:
>
> open("/dev/net/tun", O_RDWR)
>
> and continue as usual.
>
> However, when I try to use sysopen in perl like
>
> sysopen(TUNNELDEV, "/dev/net/tun", O_RDWR);
>
> from the strace (truss) output I can see that instead it tries to do:
>
> open("/dev/net/tun", O_RDWR|O_LARGEFILE)
>
> which for some VERY strange reason succeeds but the file descriptor is
> left in a bad state, so it is really unusable. For anything I try to do
> afterwards, I get a
>
> EBADFD (File descriptor in bad state).
>
> As I have come down to the systel call level, there is no other reason
> for this problem that I can think of except the O_LARGEFILE flag.
> Indeed, a simple C program works quite fine without that flag.
Just to make sure it is absolutely nailed down, does the simple C program
stop working fine if you add the O_LARGEFILE in?
> I also have tried to use POSIX::open but it still adds the flag.
>
> The documentation clearly states that from perl 5.6 and forth, the
> O_LARGEFILE will be used whenever possible. But I really need to bypass
> this and generate an open system call without it.
Maybe you could compile perl without large file support?
Or write a small C server that will accept socket connections and
proxy /dev/net/tun over the socket.
Xho
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