I've found a problem with job control when the init process is restarted.
If the system boots for the first time, I get job control on a serial terminal -
no problems. However, when I restart init by issuing "init -q", then the shell
no longer has job control.
I traced this a problem in console_init in the file init.c. What was happening
after the restart is that the first compare
if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
...
} else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
...
} else {
... // assume /dev/console
}
returned error and subsequently the code assumes /dev/console as the console,
which does not support job control.
Checking the errno after the first call showed that the system was complaining
about the file descriptor. This is probably because the previous init process
had closed all its file descriptors which the new init process had inherited.
andersen@busybox.net wrote:
>Message: 4
>Modified Files:
> init.c
>Log Message:
>Remove code for unsupported kernel versions
Hmm. Current init.c have check >= 2.2.0 kernel one time too.
Ok. Last patch removed this point and move common init code to new file for
/init dir
over the years. Well I finally took the time to track this down. It turns out
that inside linux/kernel/sys.c the kernel will call
machine_halt();
do_exit(0);
when halting, or will call
machine_power_off();
do_exit(0);
during a reboot. Unlike sysv init, we call reboot from within the init
process, so if the call to machine_halt() or machine_power_off() returns, the call to do_exit(0) will cause the kernel to panic. Which is a very
bad thing to happen.
So I just added this little patch to fork and call the reboot
syscall from within the forked child process, thereby neatly
avoiding the problem.
But IMHO, both calls to do_exit(0) within linux/kernel/sys.c
are bugs and should be fixed.
-Erik
modified Kbuild system I put into uClibc. With this, there should be no more
need to modify Rules.mak since I've moved all the interesting options into the
config system. I think I've got everything updated, but you never know, I may
have made some mistakes, so watch closely.
-Erik
best way to go. Sysvinit does not provide a controlling tty since it doesn't
even try to open ttys for apps. We do. So we should _try_ to provide a
controlling tty if possible, but we needn't freak out if it doesn't work. This
way we won't need to use openvt or similar, we'll just have init do the Right
Thing(tm).
New complex patch for decrease size devel version. Requires previous patch.
Also removed small problems from dutmp and tar applets.
Also includes vodz' last_patch61_2:
Last patch correcting comment for #endif and more integrated
with libbb (very reduce size if used "cat" applet also).
Requires last_patch61 for modutils/config.in.
control turned off" bug, console_setup() was called with a closed file
descriptor, setsid() inconsistancy, and silly string handling bugs. I have
modified his patch to allow the askfirst init actions to have a controlling
terminal.
the busybox development tree. This eliminates the use of recursive make, and
once again allows us to run 'make' in a subdirectory with the expected result.
And things are now much faster too. Greatly improved IMHO...
-Erik
start-stop-daemon man page:
-b|--background
Typically used with programs that don't detach on their own.
This option will force start-stop-daemon to fork before starting
the process, and force it into the background. WARNING:
start-stop-daemon cannot check the exit status if the process
fails to execute for any reason. This is a last resort, and is
only meant for programs that either make no sense forking on
their own, or where it's not feasible to add the code for it to
do this itself.
This is usefull for applets like watchdog
Very minimal last corrections:
1) busybox.c: fix warining
2) docs/: add applets for list from pwd_grp
3) usage.h: add -n option for route
4) run_parts.c: many todo fix for busybox style
5) addgroup.c: add #ifdef CONFIG_FEATURE_SHADOWPASSWDS, reduce one
perror_msg
6) adduser.c: fix bug "variable i not initialize" and
add #ifdef CONFIG_FEATURE_SHADOWPASSWDS
that into a pid_t, which is unsigned on a number archs. Furthermore,
find_pid_by_name() would _never_ return an error if the intended proces
was "init", but instead would return 1, meaning we would fail to work
on 2.4.x kernels running an initrd...
-Erik
Kimdon <dwhedon@gordian.com> on october 7th -- the day I was fired from
Lineo. So it seems I totally forgot about this patch until now.
Sorry about that David!
1st makes init smaller, and fixes a bug with AskFirst. Reading from
/dev/null gives EOF.
2nd makes init run the command's in the order of inittab, as in
FIFO instead of LIFO.
This way, we can new get rid of all that tedious #define rubbish we used to
need to enable specific messages. This way is enormously simpler, and as a
bonus also ends up saving us 96 bytes.
-Erik
environment variables set from the kernel command line to be inherited
bu application programs. Slightly changed to special case handling of
TERM, so that it has sane defaults when on a serial console.
-Erik
to multibuild.pl. I did a little formatting adjustments to make it
_very_ obvious when things stop working. I also removed the USE_PROCFS
config option -- just do the right thing when USE_DEVPS_PATCH is enabled.
-Erik
