reboot
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From: Stephane CHAZELAS on 13 Jan 2010 01:59 2010-01-13, 00:53(-05), Barry Margolin: > In article > <9711e184-7cb6-46e4-9c55-d4b7bd03aea4(a)j19g2000yqk.googlegroups.com>, > David Schwartz <davids(a)webmaster.com> wrote: > >> On Jan 12, 2:20�pm, neilsolent <n...(a)solenttechnology.co.uk> wrote: >> >> > The C program below certainly reboots my Solaris 10 system, but it >> > does not seem to do it cleanly (doesn't send SIGTERM to the running >> > processes). If I run the Solaris reboot command though, that does seem >> > to cleanly reboot. >> > How come? >> >> The reboot command sends a SIGTERM to the running process before >> rebooting and your code doesn't. Your question is self-answering. Your >> code doesn't send a SIGTERM to the running processes because it >> contains no code that would do that anywhere in it. It simply commands >> the system to reboot, so that's what happens. >> >> DS > > More to the point, the reboot() system call is what the reboot command > calls AFTER it has broadcast a shutdown notice on all the terminals, > sent all the SIGTERMs, etc. Eventually it has to tell the OS to reboot, > and it does it using this system call. From the reboot man page: Although reboot can be run by the super-user at any time, shutdown(1M) is normally used first to warn all users logged in of the impending loss of service. See shutdown(1M) for details. NOTES The reboot utility does not execute the scripts in /etc/rcnum.d or exe- cute shutdown actions in inittab(4). To ensure a complete shutdown of system services, use shutdown(1M) or init(1M) to reboot a Solaris sys- tem. To sum up, shutdown does more than "telinit 6" that does more than "reboot" So system("shutdown -r now") is probably gonna be the best solution (and probably the most portable as well). -- St�phane
From: neilsolent on 13 Jan 2010 10:33 Thanks for your posts. I was hoping that the C libs would have a useful system call that took care of handling a clean reboot. Going with a modified version of your idea (as "shutdown -r now" is invalid syntax on my Solaris 10 platform): [C code]: system("reboot.sh"); [reboot.sh] #!/bin/sh case "`uname -s`" in 'SunOS') /usr/sbin/shutdown -y -i 6 ;; *) /sbin/shutdown -r now -t 60 ;; esac Running this, I find the situation is worse than just calling the reboot command. Perhaps reboot is sending the SIGTERMs which causes processes to end that don't have shutdown scripts, whereas shutdown assumes each process has a shutdown script ? I am unsure what the best solution is now. I want a simple way of doing a clean reboot from a C program across UNIX platforms. thanks again, Neil
From: neilsolent on 16 Jan 2010 10:52 To recap. We don't think there is any C function call that will do a clean reboot on UNIX. We need to call a shell command. So we want a shell script that will check the version of UNIX and do a clean reboot. On Solaris, I find /usr/bin/shutdown does not seem to SIGTERM all the processes (I guess - it assumes every process has a shutdown script if it needs it). I find the reboot command does send a SIGTERM to the processes. Ideally - the shutdown scripts are run, and remaining processes are signalled. Thoughts / experiences anyone? What's a standard script for rebooting UNIX? Bueller? Anyone?
From: Alan Curry on 16 Jan 2010 17:22 In article <81648a97-e547-452b-8f4f-b386af42a35c(a)v25g2000yqk.googlegroups.com>, neilsolent <n(a)solenttechnology.co.uk> wrote: >To recap. >We don't think there is any C function call that will do a clean >reboot on UNIX. Maybe this is because a reboot is a major event in unix, and if it needs to be done, it deserves to be supervised by an administrator familiar with the system (who knows the commands, and can decide how many minutes, hours, or days ahead of time the downtime should be announced to the users), not by some third-party shell script hacked together with fragments gathered from Usenet. "Reboots are for kernel upgrades", the saying goes... -- Alan Curry
From: David Schwartz on 16 Jan 2010 17:26
On Jan 16, 7:52 am, neilsolent <n...(a)solenttechnology.co.uk> wrote: > To recap. > We don't think there is any C function call that will do a clean > reboot on UNIX. > We need to call a shell command. > So we want a shell script that will check the version of UNIX and do a > clean reboot. Cannot be done. The proper way to do a clean reboot is critically system dependent. You must ask a human being for permission and for instruction. There is no "one right way" to do a clean reboot. On some machines, it requires arranging load migration to other machines in the cluster. On some machines, it can only be done intentionally during a maintenance window. > On Solaris, I find /usr/bin/shutdown does not seem to SIGTERM all the > processes (I guess - it assumes every process has a shutdown script if > it needs it). I find the reboot command does send a SIGTERM to the > processes. Ideally - the shutdown scripts are run, and remaining > processes are signalled. > Thoughts / experiences anyone? > What's a standard script for rebooting UNIX? There is no standard script. Every system is different, and rightfully and necessarily so. Why are you rebooting the machine from a script anyway? DS |