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voyager_thread.c

/* -*- mode: c; c-basic-offset: 8 -*- */

/* Copyright (C) 2001
 *
 * Author: J.E.J.Bottomley@HansenPartnership.com
 *
 * linux/arch/i386/kernel/voyager_thread.c
 *
 * This module provides the machine status monitor thread for the
 * voyager architecture.  This allows us to monitor the machine
 * environment (temp, voltage, fan function) and the front panel and
 * internal UPS.  If a fault is detected, this thread takes corrective
 * action (usually just informing init)
 * */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/kmod.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/kthread.h>
#include <asm/desc.h>
#include <asm/voyager.h>
#include <asm/vic.h>
#include <asm/mtrr.h>
#include <asm/msr.h>


struct task_struct *voyager_thread;
static __u8 set_timeout;

static int
execute(const char *string)
{
      int ret;

      char *envp[] = {
            "HOME=/",
            "TERM=linux",
            "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
            NULL,
      };
      char *argv[] = {
            "/bin/bash",
            "-c",
            (char *)string,
            NULL,
      };

      if ((ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC)) != 0) {
            printk(KERN_ERR "Voyager failed to run \"%s\": %i\n",
                   string, ret);
      }
      return ret;
}

static void
check_from_kernel(void)
{
      if(voyager_status.switch_off) {
            
            /* FIXME: This should be configurable via proc */
            execute("umask 600; echo 0 > /etc/initrunlvl; kill -HUP 1");
      } else if(voyager_status.power_fail) {
            VDEBUG(("Voyager daemon detected AC power failure\n"));
            
            /* FIXME: This should be configureable via proc */
            execute("umask 600; echo F > /etc/powerstatus; kill -PWR 1");
            set_timeout = 1;
      }
}

static void
check_continuing_condition(void)
{
      if(voyager_status.power_fail) {
            __u8 data;
            voyager_cat_psi(VOYAGER_PSI_SUBREAD, 
                        VOYAGER_PSI_AC_FAIL_REG, &data);
            if((data & 0x1f) == 0) {
                  /* all power restored */
                  printk(KERN_NOTICE "VOYAGER AC power restored, cancelling shutdown\n");
                  /* FIXME: should be user configureable */
                  execute("umask 600; echo O > /etc/powerstatus; kill -PWR 1");
                  set_timeout = 0;
            }
      }
}

static int
thread(void *unused)
{
      printk(KERN_NOTICE "Voyager starting monitor thread\n");

      for (;;) {
            set_current_state(TASK_INTERRUPTIBLE);
            schedule_timeout(set_timeout ? HZ : MAX_SCHEDULE_TIMEOUT);

            VDEBUG(("Voyager Daemon awoken\n"));
            if(voyager_status.request_from_kernel == 0) {
                  /* probably awoken from timeout */
                  check_continuing_condition();
            } else {
                  check_from_kernel();
                  voyager_status.request_from_kernel = 0;
            }
      }
}

static int __init
voyager_thread_start(void)
{
      voyager_thread = kthread_run(thread, NULL, "kvoyagerd");
      if (IS_ERR(voyager_thread)) {
            printk(KERN_ERR "Voyager: Failed to create system monitor thread.\n");
            return PTR_ERR(voyager_thread);
      }
      return 0;
}


static void __exit
voyager_thread_stop(void)
{
      kthread_stop(voyager_thread);
}

module_init(voyager_thread_start);
module_exit(voyager_thread_stop);

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