patch-2.1.43 linux/drivers/char/sysrq.c

• Lines: 249
• Date: Thu Jun 12 16:22:06 1997
• Orig file: v2.1.42/linux/drivers/char/sysrq.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.42/linux/drivers/char/sysrq.c linux/drivers/char/sysrq.c
@@ -0,0 +1,248 @@
+/* -*- linux-c -*-
+ *
+ *	$Id: sysrq.c,v 1.2 1997/05/31 18:33:11 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 19:					    /* R -- Reset raw mode */
+		kbd->kbdmode = VC_XLATE;
+		printk("Keyboard mode set to XLATE\n");
+		break;
+	case 30:					    /* A -- SAK */
+		printk("SAK\n");
+		do_SAK(tty);
+		reset_vc(fg_console);
+		break;
+	case 48:					    /* B -- boot immediately */
+		printk("Resetting\n");
+		machine_restart(NULL);
+		break;
+#ifdef __sparc__
+	case 35:					    /* H -- halt immediately */
+		printk("Halting\n");
+		halt_now();
+		break;
+#endif
+#ifdef CONFIG_APM
+	case 24:					    /* O -- power off */
+		printk("Power off\n");
+		apm_set_power_state(APM_STATE_OFF);
+		break;
+#endif
+	case 31:					    /* S -- emergency sync */
+		printk("Emergency Sync\n");
+		emergency_sync_scheduled = EMERG_SYNC;
+		wakeup_bdflush(0);
+		break;
+	case 22:					    /* U -- emergency remount R/O */
+		printk("Emergency Remount R/O\n");
+		emergency_sync_scheduled = EMERG_REMOUNT;
+		wakeup_bdflush(0);
+		break;
+	case 25:					    /* P -- show PC */
+		printk("Show Regs\n");
+		if (pt_regs)
+			show_regs(pt_regs);
+		break;
+	case 20:					    /* T -- show task info */
+		printk("Show State\n");
+		show_state();
+		break;
+	case 50:					    /* M -- show memory info */
+		printk("Show Memory\n");
+		show_mem();
+		break;
+	case 2 ... 11:					    /* 0-9 -- set console logging level */
+		key -= 2;
+		if (key == 10)
+			key = 0;
+		orig_log_level = key;
+		printk("Log level set to %d\n", key);
+		break;
+	case 18:					    /* 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 37:					    /* K -- kill all user processes */
+		printk("Kill All Tasks\n");
+		send_sig_all(SIGKILL, 0);
+		orig_log_level = 8;
+		break;
+	case 38:					    /* 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_inode && file->f_count && S_ISREG(file->f_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");
+}