Messages in this thread | | | Date | Thu, 18 Nov 2010 14:41:23 +0000 | From | Alan Cox <> | Subject | Re: tty: add 'active' sysfs attribute to tty0 and console device |
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> How can I detect the major and minor of the primary console device > of /dev/console without controlling tty? Even if my old blogd
In the general case you can't - because a console may not have a tty. Quite a few don't. For the cases where one has a device I can't see a clean way to do it as an fstat on the console device will give you the console major/mninor and some code depends upon that.
The iniability to get it is clearly a flaw and you need the sysfs link or a sysfs list of consoles (again remembering many of them won't have a tty bound).
> and the bootlogd(8) of SysInitV using TIOCCONS are outdated by SystemD > the question before doing the TIOCCONS is which is the primary console > device to e.g. create the device node in initrd or for bootlogd(8) > to write a copy of the console messages back to the original > primary console (and the other console devices).
For init it is /dev/console as opened at boot time and passed to the initial user init task but with no nice way to work back to a device node.
Incidentally the primary console (as in printk) can be accessed as a tty via the ttyprintk driver which got added recently because embedded people wanted to use the printk interface as a (write only) tty console as well.
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