Re: Add login_tty

[Szabolcs Nagy <nsz@port70.net>]

* Felix Janda <felix.janda@posteo.de> [2014-08-26 18:56:28 +0200]:
> --- /dev/null
> +++ b/src/misc/login_tty.c
> @@ -0,0 +1,14 @@
> +#include <utmp.h>
> +#include <sys/ioctl.h>
> +#include <unistd.h>
> +
> +int login_tty(int fd)
> +{
> +	setsid();
> +	if (ioctl(fd, TIOCSCTTY, (char *)0)) return -1;
> +	dup2(fd, 0);
> +	dup2(fd, 1);
> +	dup2(fd, 2);
> +	if (fd>2) close(fd);
> +	return 0;
> +}

i recently came across this:
http://lxr.free-electrons.com/source/fs/file.c#L751

so dup2 may spuriously fail with EBUSY on linux

the current forkpty does not check dup2 either, but i
wonder if it should be

 while(dup2(fd,0)==-1 && errno==EBUSY);

instead