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/* -*- linux-c -*-
*
* $Id: sysrq.c,v 1.4 1997/07/17 11:54:15 mj Exp $
*
* Linux Magic System Request Key Hacks
*
* (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
* based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
*/
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/kdev_t.h>
#include <linux/major.h>
#include <linux/reboot.h>
#include <linux/sysrq.h>
#include <linux/kbd_kern.h>
#include <asm/ptrace.h>
#include <asm/smp_lock.h>
#ifdef CONFIG_APM
#include <linux/apm_bios.h>
#endif
extern void wakeup_bdflush(int);
extern void reset_vc(unsigned int);
extern int console_loglevel;
extern struct vfsmount *vfsmntlist;
#ifdef __sparc__
extern void halt_now(void);
#endif
/* Send a signal to all user processes */
static void send_sig_all(int sig, int even_init)
{
struct task_struct *p;
for_each_task(p) {
if (p->pid && p->mm != &init_mm) { /* Not swapper nor kernel thread */
if (p->pid == 1 && even_init) /* Ugly hack to kill init */
p->pid = 0x8000;
force_sig(sig, p);
}
}
}
/*
* This function is called by the keyboard handler when SysRq is pressed
* and any other keycode arrives.
*/
void handle_sysrq(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty)
{
int orig_log_level = console_loglevel;
console_loglevel = 7;
printk(KERN_INFO "SysRq: ");
switch (key) {
case 'r': /* R -- Reset raw mode */
if (kbd) {
kbd->kbdmode = VC_XLATE;
printk("Keyboard mode set to XLATE\n");
}
break;
case 'a': /* A -- SAK */
printk("SAK\n");
if (tty)
do_SAK(tty);
reset_vc(fg_console);
break;
case 'b': /* B -- boot immediately */
printk("Resetting\n");
machine_restart(NULL);
break;
#ifdef __sparc__
case 'h': /* H -- halt immediately */
printk("Halting\n");
halt_now();
break;
#endif
#ifdef CONFIG_APM
case 'o': /* O -- power off */
printk("Power off\n");
apm_set_power_state(APM_STATE_OFF);
break;
#endif
case 's': /* S -- emergency sync */
printk("Emergency Sync\n");
emergency_sync_scheduled = EMERG_SYNC;
wakeup_bdflush(0);
break;
case 'u': /* U -- emergency remount R/O */
printk("Emergency Remount R/O\n");
emergency_sync_scheduled = EMERG_REMOUNT;
wakeup_bdflush(0);
break;
case 'p': /* P -- show PC */
printk("Show Regs\n");
if (pt_regs)
show_regs(pt_regs);
break;
case 't': /* T -- show task info */
printk("Show State\n");
show_state();
break;
case 'm': /* M -- show memory info */
printk("Show Memory\n");
show_mem();
break;
case '0' ... '9': /* 0-9 -- set console logging level */
orig_log_level = key - '0';
printk("Log level set to %d\n", orig_log_level);
break;
case 'e': /* E -- terminate all user processes */
printk("Terminate All Tasks\n");
send_sig_all(SIGTERM, 0);
orig_log_level = 8; /* We probably have killed syslogd */
break;
case 'k': /* K -- kill all user processes */
printk("Kill All Tasks\n");
send_sig_all(SIGKILL, 0);
orig_log_level = 8;
break;
case 'l': /* L -- kill all processes including init */
printk("Kill ALL Tasks (even init)\n");
send_sig_all(SIGKILL, 1);
orig_log_level = 8;
break;
default: /* Unknown: help */
printk("unRaw sAk Boot "
#ifdef __sparc__
"Halt "
#endif
#ifdef CONFIG_APM
"Off "
#endif
"Sync Unmount showPc showTasks showMem loglevel0-8 tErm Kill killalL\n");
}
console_loglevel = orig_log_level;
}
/* Aux routines for the syncer */
static void all_files_read_only(void) /* Kill write permissions of all files */
{
struct file *file;
for (file = inuse_filps; file; file = file->f_next)
if (file->f_dentry && file->f_count && S_ISREG(file->f_dentry->d_inode->i_mode))
file->f_mode &= ~2;
}
static int is_local_disk(kdev_t dev) /* Guess if the device is a local hard drive */
{
unsigned int major = MAJOR(dev);
switch (major) {
case IDE0_MAJOR:
case IDE1_MAJOR:
case IDE2_MAJOR:
case IDE3_MAJOR:
case SCSI_DISK_MAJOR:
return 1;
default:
return 0;
}
}
static void go_sync(kdev_t dev, int remount_flag)
{
printk(KERN_INFO "%sing device %04x ... ",
remount_flag ? "Remount" : "Sync",
dev);
if (remount_flag) { /* Remount R/O */
struct super_block *sb = get_super(dev);
struct vfsmount *vfsmnt;
int ret, flags;
if (!sb) {
printk("Superblock not found\n");
return;
}
if (sb->s_flags & MS_RDONLY) {
printk("R/O\n");
return;
}
quota_off(dev, -1);
fsync_dev(dev);
flags = MS_RDONLY;
if (sb->s_op && sb->s_op->remount_fs) {
ret = sb->s_op->remount_fs(sb, &flags, NULL);
if (ret)
printk("error %d\n", ret);
else {
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
if ((vfsmnt = lookup_vfsmnt(sb->s_dev)))
vfsmnt->mnt_flags = sb->s_flags;
printk("OK\n");
}
} else
printk("nothing to do\n");
} else {
fsync_dev(dev); /* Sync only */
printk("OK\n");
}
}
/*
* Emergency Sync or Unmount. We cannot do it directly, so we set a special
* flag and wake up the bdflush kernel thread which immediately calls this function.
* We process all mounted hard drives first to recover from crashed experimental
* block devices and malfunctional network filesystems.
*/
int emergency_sync_scheduled;
void do_emergency_sync(void)
{
struct vfsmount *mnt;
int remount_flag;
lock_kernel();
remount_flag = (emergency_sync_scheduled == EMERG_REMOUNT);
emergency_sync_scheduled = 0;
if (remount_flag)
all_files_read_only();
for (mnt = vfsmntlist; mnt; mnt = mnt->mnt_next)
if (is_local_disk(mnt->mnt_dev))
go_sync(mnt->mnt_dev, remount_flag);
for (mnt = vfsmntlist; mnt; mnt = mnt->mnt_next)
if (!is_local_disk(mnt->mnt_dev) && MAJOR(mnt->mnt_dev))
go_sync(mnt->mnt_dev, remount_flag);
unlock_kernel();
printk(KERN_INFO "Done.\n");
}
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