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/* -*- 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>
*
* (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
* overhauled to use key registration
* based upon discusions in irc://irc.openprojects.net/#kernelnewbies
*/
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/tty.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 <linux/module.h>
#include <linux/spinlock.h>
#include <asm/ptrace.h>
extern void reset_vc(unsigned int);
extern struct list_head super_blocks;
/* Whether we react on sysrq keys or just ignore them */
int sysrq_enabled = 1;
/* Machine specific power off function */
void (*sysrq_power_off)(void);
/* Loglevel sysrq handler */
static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
int i;
i = key - '0';
console_loglevel = 7;
printk("Loglevel set to %d\n", i);
console_loglevel = i;
}
static struct sysrq_key_op sysrq_loglevel_op = {
handler: sysrq_handle_loglevel,
help_msg: "loglevel0-8",
action_msg: "Changing Loglevel",
};
/* SAK sysrq handler */
#ifdef CONFIG_VT
static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
if (tty)
do_SAK(tty);
reset_vc(fg_console);
}
static struct sysrq_key_op sysrq_SAK_op = {
handler: sysrq_handle_SAK,
help_msg: "saK",
action_msg: "SAK",
};
#endif
/* unraw sysrq handler */
static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
if (kbd)
kbd->kbdmode = VC_XLATE;
}
static struct sysrq_key_op sysrq_unraw_op = {
handler: sysrq_handle_unraw,
help_msg: "unRaw",
action_msg: "Keyboard mode set to XLATE",
};
/* reboot sysrq handler */
static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
machine_restart(NULL);
}
static struct sysrq_key_op sysrq_reboot_op = {
handler: sysrq_handle_reboot,
help_msg: "reBoot",
action_msg: "Resetting",
};
/* SYNC SYSRQ HANDLERS BLOCK */
/* do_emergency_sync helper function */
/* Guesses if the device is a local hard drive */
static int is_local_disk(kdev_t dev) {
unsigned int major;
major = MAJOR(dev);
switch (major) {
case IDE0_MAJOR:
case IDE1_MAJOR:
case IDE2_MAJOR:
case IDE3_MAJOR:
case IDE4_MAJOR:
case IDE5_MAJOR:
case IDE6_MAJOR:
case IDE7_MAJOR:
case IDE8_MAJOR:
case IDE9_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:
case XT_DISK_MAJOR:
return 1;
default:
return 0;
}
}
/* do_emergency_sync helper function */
static void go_sync(struct super_block *sb, int remount_flag)
{
int orig_loglevel;
orig_loglevel = console_loglevel;
console_loglevel = 7;
printk(KERN_INFO "%sing device %s ... ",
remount_flag ? "Remount" : "Sync",
kdevname(sb->s_dev));
if (remount_flag) { /* Remount R/O */
int ret, flags;
struct list_head *p;
if (sb->s_flags & MS_RDONLY) {
printk("R/O\n");
return;
}
file_list_lock();
for (p = sb->s_files.next; p != &sb->s_files; p = p->next) {
struct file *file = list_entry(p, struct file, f_list);
if (file->f_dentry && file_count(file)
&& S_ISREG(file->f_dentry->d_inode->i_mode))
file->f_mode &= ~2;
}
file_list_unlock();
DQUOT_OFF(sb);
fsync_dev(sb->s_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);
printk("OK\n");
}
} else
printk("nothing to do\n");
} else { /* Sync only */
fsync_dev(sb->s_dev);
printk("OK\n");
}
console_loglevel = orig_loglevel;
}
/*
* 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 super_block *sb;
int remount_flag;
int orig_loglevel;
lock_kernel();
remount_flag = (emergency_sync_scheduled == EMERG_REMOUNT);
emergency_sync_scheduled = 0;
for (sb = sb_entry(super_blocks.next);
sb != sb_entry(&super_blocks);
sb = sb_entry(sb->s_list.next))
if (is_local_disk(sb->s_dev))
go_sync(sb, remount_flag);
for (sb = sb_entry(super_blocks.next);
sb != sb_entry(&super_blocks);
sb = sb_entry(sb->s_list.next))
if (!is_local_disk(sb->s_dev) && MAJOR(sb->s_dev))
go_sync(sb, remount_flag);
unlock_kernel();
orig_loglevel = console_loglevel;
console_loglevel = 7;
printk(KERN_INFO "Done.\n");
console_loglevel = orig_loglevel;
}
static void sysrq_handle_sync(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
emergency_sync_scheduled = EMERG_SYNC;
wakeup_bdflush();
}
static struct sysrq_key_op sysrq_sync_op = {
handler: sysrq_handle_sync,
help_msg: "Sync",
action_msg: "Emergency Sync",
};
static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
emergency_sync_scheduled = EMERG_REMOUNT;
wakeup_bdflush();
}
static struct sysrq_key_op sysrq_mountro_op = {
handler: sysrq_handle_mountro,
help_msg: "Unmount",
action_msg: "Emergency Remount R/O",
};
/* END SYNC SYSRQ HANDLERS BLOCK */
/* SHOW SYSRQ HANDLERS BLOCK */
static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
if (pt_regs)
show_regs(pt_regs);
}
static struct sysrq_key_op sysrq_showregs_op = {
handler: sysrq_handle_showregs,
help_msg: "showPc",
action_msg: "Show Regs",
};
static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
show_state();
}
static struct sysrq_key_op sysrq_showstate_op = {
handler: sysrq_handle_showstate,
help_msg: "showTasks",
action_msg: "Show State",
};
static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
show_mem();
}
static struct sysrq_key_op sysrq_showmem_op = {
handler: sysrq_handle_showmem,
help_msg: "showMem",
action_msg: "Show Memory",
};
/* SHOW SYSRQ HANDLERS BLOCK */
/* SIGNAL SYSRQ HANDLERS BLOCK */
/* signal sysrq helper function
* Sends 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->mm) { /* Not swapper nor kernel thread */
if (p->pid == 1 && even_init)
/* Ugly hack to kill init */
p->pid = 0x8000;
if (p->pid != 1)
force_sig(sig, p);
}
}
}
static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
send_sig_all(SIGTERM, 0);
console_loglevel = 8;
}
static struct sysrq_key_op sysrq_term_op = {
handler: sysrq_handle_term,
help_msg: "tErm",
action_msg: "Terminate All Tasks",
};
static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
send_sig_all(SIGKILL, 0);
console_loglevel = 8;
}
static struct sysrq_key_op sysrq_kill_op = {
handler: sysrq_handle_kill,
help_msg: "kIll",
action_msg: "Kill All Tasks",
};
static void sysrq_handle_killall(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
send_sig_all(SIGKILL, 1);
console_loglevel = 8;
}
static struct sysrq_key_op sysrq_killall_op = {
handler: sysrq_handle_killall,
help_msg: "killalL",
action_msg: "Kill All Tasks (even init)",
};
/* END SIGNAL SYSRQ HANDLERS BLOCK */
/* Key Operations table and lock */
static spinlock_t sysrq_key_table_lock = SPIN_LOCK_UNLOCKED;
#define SYSRQ_KEY_TABLE_LENGTH 36
static struct sysrq_key_op *sysrq_key_table[SYSRQ_KEY_TABLE_LENGTH] = {
/* 0 */ &sysrq_loglevel_op,
/* 1 */ &sysrq_loglevel_op,
/* 2 */ &sysrq_loglevel_op,
/* 3 */ &sysrq_loglevel_op,
/* 4 */ &sysrq_loglevel_op,
/* 5 */ &sysrq_loglevel_op,
/* 6 */ &sysrq_loglevel_op,
/* 7 */ &sysrq_loglevel_op,
/* 8 */ &sysrq_loglevel_op,
/* 9 */ &sysrq_loglevel_op,
/* a */ NULL, /* Don't use for system provided sysrqs,
it is handled specially on the spark
and will never arive */
/* b */ &sysrq_reboot_op,
/* c */ NULL,
/* d */ NULL,
/* e */ &sysrq_term_op,
/* f */ NULL,
/* g */ NULL,
/* h */ NULL,
/* i */ &sysrq_kill_op,
/* j */ NULL,
#ifdef CONFIG_VT
/* k */ &sysrq_SAK_op,
#else
/* k */ NULL,
#endif
/* l */ &sysrq_killall_op,
/* m */ &sysrq_showmem_op,
/* n */ NULL,
/* o */ NULL, /* This will often be registered
as 'Off' at init time */
/* p */ &sysrq_showregs_op,
/* q */ NULL,
/* r */ &sysrq_unraw_op,
/* s */ &sysrq_sync_op,
/* t */ &sysrq_showstate_op,
/* u */ &sysrq_mountro_op,
/* v */ NULL,
/* w */ NULL,
/* x */ NULL,
/* w */ NULL,
/* z */ NULL
};
/* key2index calculation, -1 on invalid index */
static __inline__ int sysrq_key_table_key2index(int key) {
int retval;
if ((key >= '0') & (key <= '9')) {
retval = key - '0';
} else if ((key >= 'a') & (key <= 'z')) {
retval = key + 10 - 'a';
} else {
retval = -1;
}
return retval;
}
/*
* table lock and unlocking functions, exposed to modules
*/
void __sysrq_lock_table (void) { spin_lock(&sysrq_key_table_lock); }
void __sysrq_unlock_table (void) { spin_unlock(&sysrq_key_table_lock); }
/*
* get and put functions for the table, exposed to modules.
*/
struct sysrq_key_op *__sysrq_get_key_op (int key) {
struct sysrq_key_op *op_p;
int i;
i = sysrq_key_table_key2index(key);
op_p = (i == -1) ? NULL : sysrq_key_table[i];
return op_p;
}
void __sysrq_put_key_op (int key, struct sysrq_key_op *op_p) {
int i;
i = sysrq_key_table_key2index(key);
if (i != -1)
sysrq_key_table[i] = op_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) {
if (!sysrq_enabled)
return;
__sysrq_lock_table();
__handle_sysrq_nolock(key, pt_regs, kbd, tty);
__sysrq_unlock_table();
}
/*
* This is the non-locking version of handle_sysrq
* It must/can only be called by sysrq key handlers,
* as they are inside of the lock
*/
void __handle_sysrq_nolock(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
struct sysrq_key_op *op_p;
int orig_log_level;
int i, j;
if (!sysrq_enabled)
return;
orig_log_level = console_loglevel;
console_loglevel = 7;
printk(KERN_INFO "SysRq : ");
op_p = __sysrq_get_key_op(key);
if (op_p) {
printk ("%s\n", op_p->action_msg);
console_loglevel = orig_log_level;
op_p->handler(key, pt_regs, kbd, tty);
} else {
printk("HELP : ");
/* Only print the help msg once per handler */
for (i=0; i<SYSRQ_KEY_TABLE_LENGTH; i++)
if (sysrq_key_table[i]) {
for (j=0; sysrq_key_table[i] != sysrq_key_table[j]; j++);
if (j == i)
printk ("%s ", sysrq_key_table[i]->help_msg);
}
printk ("\n");
console_loglevel = orig_log_level;
}
}
EXPORT_SYMBOL(handle_sysrq);
EXPORT_SYMBOL(__handle_sysrq_nolock);
EXPORT_SYMBOL(__sysrq_lock_table);
EXPORT_SYMBOL(__sysrq_unlock_table);
EXPORT_SYMBOL(__sysrq_get_key_op);
EXPORT_SYMBOL(__sysrq_put_key_op);
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