On Thu, Mar 24, 2011 at 11:56:10PM +0000, Jurij Smakov wrote: > Hello, > > I've noticed that 2.6.38 kernel supports TIOCGDEV ioctl, which can be > used to unambigously determine the real tty device corresponding to > /dev/console [0]. I believe that by using this we can significantly > simplify reopen-console-linux script in rootskel [1], and use the > device from /var/run/console-device in finish-install's 90console [2], > instead of the current method based on looking at the fds of the > debian-installer binary. > > I expect that doing it this way will (at least) fix the installs for > machines using sunhv.c serial drivers, for which the current rootskel > detection does not work. It is quite possible though that I'm > overlooking some important details, so if you know of reasons why such > changes are not a good idea, please let me know.
I have now come up with a set of changes which implements it, see the attached patch. I've tested it on my sparc box with a 2.6.38 netboot image, with both regular and serial console. Please let me know what you think, if there are no objections, I plan to push it to the main repo and upload new rootskel next weekend (Apr 9-10). Best regards, -- Jurij Smakov [email protected] Key: http://www.wooyd.org/pgpkey/ KeyID: C99E03CC
>From d3f29283db9d58ad5b1702f66f9da15df6881526 Mon Sep 17 00:00:00 2001 From: Jurij Smakov <[email protected]> Date: Sun, 27 Mar 2011 20:14:56 +0100 Subject: [PATCH] Use TIOCGDEV ioctl to find real serial console device on Linux. Kernels >= 2.6.38 support TIOCGDEV ioctl, which allows to unambigously determine the real device corresponding to /dev/console. This change adds support to using if for real console device detection to rootskel. --- debian/changelog | 2 ++ src/sbin/Makefile | 10 +++++++--- src/sbin/get-real-console-linux.c | 34 ++++++++++++++++++++++++++++++++++ src/sbin/reopen-console-linux | 8 +++++++- 4 files changed, 50 insertions(+), 4 deletions(-) create mode 100644 src/sbin/get-real-console-linux.c diff --git a/debian/changelog b/debian/changelog index 487f4c0..e7e31f7 100644 --- a/debian/changelog +++ b/debian/changelog @@ -7,6 +7,8 @@ rootskel (1.94) UNRELEASED; urgency=low [ Jurij Smakov ] * Set DEB_HOST_ARCH_OS in src/Makefile to make sure that everything builds correctly without help from dpkg-buildpackage. + * Switch to using TIOCGDEV ioctl for detection of the real console for + kernels >= 2.6.38. -- Samuel Thibault <[email protected]> Sat, 19 Mar 2011 20:21:40 +0100 diff --git a/src/sbin/Makefile b/src/sbin/Makefile index 64c91d3..dec554e 100644 --- a/src/sbin/Makefile +++ b/src/sbin/Makefile @@ -13,22 +13,26 @@ files_exec = \ ifeq ($(DEB_HOST_ARCH_OS),linux) files_exec += \ - console-type + console-type \ + get-real-console-linux endif console-type: console-type.c gcc -Os -Wall console-type.c -o console-type +get-real-console-linux: + gcc -Os -Wall get-real-console-linux.c -o get-real-console-linux + steal-ctty: steal-ctty.c gcc -Os -Wall steal-ctty.c -o steal-ctty ifeq ($(DEB_HOST_ARCH_OS),linux) -build: console-type steal-ctty +build: console-type get-real-console-linux steal-ctty else build: steal-ctty endif clean: - rm -f console-type steal-ctty + rm -f console-type get-real-console-linux steal-ctty include ../../Makefile.inc diff --git a/src/sbin/get-real-console-linux.c b/src/sbin/get-real-console-linux.c new file mode 100644 index 0000000..89c3a24 --- /dev/null +++ b/src/sbin/get-real-console-linux.c @@ -0,0 +1,34 @@ +/* + * Licensed under GPLv2 + * + * Print out major:minor number of the real console device, + * using the TIOCGDEV ioctl (only works on kernels >= 2.6.38). + * + * Copyright (c) 2011 Jurij Smakov <[email protected]> + */ + +#include <stdio.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> + +#define TIOCGDEV _IOR('T', 0x32, unsigned int) + +int main() +{ + int fd = 0; + unsigned int dev; + + fd = open("/dev/console", O_WRONLY, 0); + if (fd < 0) { + perror("open"); + return(1); + } + if (ioctl(fd, TIOCGDEV, &dev) < 0) { + perror("ioctl"); + return(2); + } + printf("%d:%d\n", major(dev), minor(dev)); + return(0); +} diff --git a/src/sbin/reopen-console-linux b/src/sbin/reopen-console-linux index 4e65a13..9062a8a 100755 --- a/src/sbin/reopen-console-linux +++ b/src/sbin/reopen-console-linux @@ -14,9 +14,15 @@ if ! [ -f /var/run/console-device ]; then console="$(dmesg -s 65535 | sed -n -r -e 's/(.*\])? *console handover: boot \[.*\] -> real \[(.*)\]$/\2/p')" ;; - *) # >=2.6.32 + 2.6.3[234567]*) console="$(dmesg -s 65535 | sed -n -r -e 's/(.*\])? *console \[(.*)\] enabled, bootconsole disabled$/\2/p')" + ;; + *) # >= 2.6.38 + console_major_minor="$(get-real-console-linux)" + console_raw="$(readlink "/sys/dev/char/${console_major_minor}")" + console="${console_raw##*/}" + ;; esac # Except if it is the wrong type... -- 1.7.2.3
