Re: Can I open a special file with major/minor instead of name?

Richard Gooch (Richard.Gooch@atnf.CSIRO.AU)
Mon, 15 Jun 1998 12:11:37 +1000

Dave Cinege writes:
> Richard Gooch wrote:
> >
> > > So.....how can I do this: (void) open( MKDEV(TTY_MAJOR,1) ,O_RDWR,0);
> > > with 2.0?
> >
> > Check out <chrdev_open> in fs/devices.c
>
> I knew about this but I didn't think it opened it right at fd 0.
>
> Well it looks like it...might. Linuxrc gets run fine but the kernel starts
> screaming at me:
>
> Warning: dev (04:01) tty->count(1) != #fd's(0) in do_tty_hangup
>
> Warning: dev (04:01) tty->count(3) != #fd's(2) in tty_open
> Warning: dev (04:01) tty->count(3) != #fd's(2) in release_dev
>
> Warning: dev (04:01) tty->count(2) != #fd's(1) in tty_open
> Warning: dev (04:01) tty->count(2) != #fd's(1) in release_dev
>
>
> Am I not closing it right? (Look for major stupidities, I'm not in my C groove
> right now : P)
>
>
> static int do_linuxrc(void * shell)
> {
> int rc;
> struct inode inode;
> struct file file;
>
> static char *argv[] = { "linuxrc", NULL, };
>
> close(0);close(1);close(2);
> setsid();
>
> memset(&file, 0, sizeof(file));
> memset(&inode, 0, sizeof(inode));
> inode.i_rdev = MKDEV(TTY_MAJOR,1);
> file.f_mode = 3;
> file.f_inode = &inode;
> (void) chrdev_open(&inode, &file);
> (void) dup(0);
> (void) dup(0);
>
> rc = execve(shell, argv, envp_init);
>
> if (file.f_op->release)
> file.f_op->release(&inode, &file);
>
> return rc;
> }

You probably should use <get_empty_filp> in fs/file_table.c

Regards,

Richard....

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