/* -*- linux-c -*- * *	$Id: sysrq.c,v 1.15 1998/08/23 14:56:41 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 <linux/quotaops.h>#include <linux/smp_lock.h>#include <asm/ptrace.h>#ifdef CONFIG_APM#include <linux/apm_bios.h>#endifextern void wakeup_bdflush(int);extern void reset_vc(unsigned int);extern int console_loglevel;extern struct vfsmount *vfsmntlist;/* 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;	if (!key)		return;	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;#ifdef CONFIG_VT	case 'k':					    /* K -- SAK */		printk("SAK\n");		if (tty)			do_SAK(tty);		reset_vc(fg_console);		break;#endif	case 'b':					    /* B -- boot immediately */		printk("Resetting\n");		machine_restart(NULL);		break;#ifdef CONFIG_APM	case 'o':					    /* O -- power off */		printk("Power off\n");		apm_power_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 'i':					    /* I -- 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 */		if (kbd)			printk("unRaw ");#ifdef CONFIG_VT		if (tty)			printk("saK ");#endif		printk("Boot "#ifdef CONFIG_APM		       "Off "#endif		       "Sync Unmount showPc showTasks showMem loglevel0-8 tErm kIll killalL\n");		/* Don't use 'A' as it's handled specially on the Sparc */	}	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_DISK0_MAJOR:	case SCSI_DISK1_MAJOR:	case SCSI_DISK2_MAJOR:	case SCSI_DISK3_MAJOR:	case SCSI_DISK4_MAJOR:	case SCSI_DISK5_MAJOR:	case SCSI_DISK6_MAJOR:	case SCSI_DISK7_MAJOR:		return 1;	default:		return 0;	}}static void go_sync(kdev_t dev, int remount_flag){	printk(KERN_INFO "%sing device %s ... ",	       remount_flag ? "Remount" : "Sync",	       kdevname(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;		}		DQUOT_OFF(dev);		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");}