453 lines
11 KiB
C
453 lines
11 KiB
C
/* -*- linux-c -*-
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*
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* $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
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*
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* Linux Magic System Request Key Hacks
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*
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* (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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* based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
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*
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* (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
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* overhauled to use key registration
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* based upon discusions in irc://irc.openprojects.net/#kernelnewbies
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*/
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#include <linux/config.h>
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#include <linux/sched.h>
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#include <linux/interrupt.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/tty.h>
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#include <linux/mount.h>
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#include <linux/kdev_t.h>
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#include <linux/major.h>
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#include <linux/reboot.h>
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#include <linux/sysrq.h>
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#include <linux/kbd_kern.h>
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#include <linux/quotaops.h>
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#include <linux/smp_lock.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/suspend.h>
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#include <linux/writeback.h>
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#include <linux/buffer_head.h> /* for fsync_bdev() */
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#include <linux/swap.h>
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#include <linux/spinlock.h>
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#include <linux/vt_kern.h>
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#include <linux/workqueue.h>
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#include <linux/kexec.h>
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#include <asm/ptrace.h>
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/* Whether we react on sysrq keys or just ignore them */
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int sysrq_enabled = 1;
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/* Loglevel sysrq handler */
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static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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int i;
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i = key - '0';
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console_loglevel = 7;
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printk("Loglevel set to %d\n", i);
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console_loglevel = i;
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}
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static struct sysrq_key_op sysrq_loglevel_op = {
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.handler = sysrq_handle_loglevel,
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.help_msg = "loglevel0-8",
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.action_msg = "Changing Loglevel",
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.enable_mask = SYSRQ_ENABLE_LOG,
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};
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/* SAK sysrq handler */
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#ifdef CONFIG_VT
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static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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if (tty)
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do_SAK(tty);
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reset_vc(vc_cons[fg_console].d);
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}
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static struct sysrq_key_op sysrq_SAK_op = {
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.handler = sysrq_handle_SAK,
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.help_msg = "saK",
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.action_msg = "SAK",
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.enable_mask = SYSRQ_ENABLE_KEYBOARD,
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};
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#endif
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#ifdef CONFIG_VT
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/* unraw sysrq handler */
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static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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struct kbd_struct *kbd = &kbd_table[fg_console];
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if (kbd)
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kbd->kbdmode = VC_XLATE;
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}
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static struct sysrq_key_op sysrq_unraw_op = {
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.handler = sysrq_handle_unraw,
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.help_msg = "unRaw",
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.action_msg = "Keyboard mode set to XLATE",
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.enable_mask = SYSRQ_ENABLE_KEYBOARD,
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};
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#endif /* CONFIG_VT */
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#ifdef CONFIG_KEXEC
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/* crashdump sysrq handler */
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static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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crash_kexec(pt_regs);
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}
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static struct sysrq_key_op sysrq_crashdump_op = {
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.handler = sysrq_handle_crashdump,
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.help_msg = "Crashdump",
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.action_msg = "Trigger a crashdump",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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#endif
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/* reboot sysrq handler */
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static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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local_irq_enable();
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emergency_restart();
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}
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static struct sysrq_key_op sysrq_reboot_op = {
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.handler = sysrq_handle_reboot,
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.help_msg = "reBoot",
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.action_msg = "Resetting",
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.enable_mask = SYSRQ_ENABLE_BOOT,
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};
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static void sysrq_handle_sync(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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emergency_sync();
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}
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static struct sysrq_key_op sysrq_sync_op = {
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.handler = sysrq_handle_sync,
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.help_msg = "Sync",
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.action_msg = "Emergency Sync",
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.enable_mask = SYSRQ_ENABLE_SYNC,
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};
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static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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emergency_remount();
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}
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static struct sysrq_key_op sysrq_mountro_op = {
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.handler = sysrq_handle_mountro,
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.help_msg = "Unmount",
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.action_msg = "Emergency Remount R/O",
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.enable_mask = SYSRQ_ENABLE_REMOUNT,
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};
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/* END SYNC SYSRQ HANDLERS BLOCK */
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/* SHOW SYSRQ HANDLERS BLOCK */
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static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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if (pt_regs)
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show_regs(pt_regs);
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}
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static struct sysrq_key_op sysrq_showregs_op = {
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.handler = sysrq_handle_showregs,
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.help_msg = "showPc",
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.action_msg = "Show Regs",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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show_state();
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}
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static struct sysrq_key_op sysrq_showstate_op = {
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.handler = sysrq_handle_showstate,
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.help_msg = "showTasks",
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.action_msg = "Show State",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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show_mem();
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}
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static struct sysrq_key_op sysrq_showmem_op = {
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.handler = sysrq_handle_showmem,
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.help_msg = "showMem",
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.action_msg = "Show Memory",
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.enable_mask = SYSRQ_ENABLE_DUMP,
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};
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/* SHOW SYSRQ HANDLERS BLOCK */
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/* SIGNAL SYSRQ HANDLERS BLOCK */
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/* signal sysrq helper function
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* Sends a signal to all user processes */
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static void send_sig_all(int sig)
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{
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struct task_struct *p;
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for_each_process(p) {
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if (p->mm && p->pid != 1)
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/* Not swapper, init nor kernel thread */
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force_sig(sig, p);
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}
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}
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static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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send_sig_all(SIGTERM);
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console_loglevel = 8;
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}
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static struct sysrq_key_op sysrq_term_op = {
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.handler = sysrq_handle_term,
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.help_msg = "tErm",
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.action_msg = "Terminate All Tasks",
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.enable_mask = SYSRQ_ENABLE_SIGNAL,
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};
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static void moom_callback(void *ignored)
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{
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out_of_memory(GFP_KERNEL, 0);
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}
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static DECLARE_WORK(moom_work, moom_callback, NULL);
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static void sysrq_handle_moom(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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schedule_work(&moom_work);
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}
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static struct sysrq_key_op sysrq_moom_op = {
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.handler = sysrq_handle_moom,
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.help_msg = "Full",
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.action_msg = "Manual OOM execution",
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};
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static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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send_sig_all(SIGKILL);
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console_loglevel = 8;
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}
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static struct sysrq_key_op sysrq_kill_op = {
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.handler = sysrq_handle_kill,
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.help_msg = "kIll",
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.action_msg = "Kill All Tasks",
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.enable_mask = SYSRQ_ENABLE_SIGNAL,
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};
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/* END SIGNAL SYSRQ HANDLERS BLOCK */
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static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs,
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struct tty_struct *tty)
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{
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normalize_rt_tasks();
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}
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static struct sysrq_key_op sysrq_unrt_op = {
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.handler = sysrq_handle_unrt,
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.help_msg = "Nice",
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.action_msg = "Nice All RT Tasks",
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.enable_mask = SYSRQ_ENABLE_RTNICE,
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};
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/* Key Operations table and lock */
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static DEFINE_SPINLOCK(sysrq_key_table_lock);
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#define SYSRQ_KEY_TABLE_LENGTH 36
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static struct sysrq_key_op *sysrq_key_table[SYSRQ_KEY_TABLE_LENGTH] = {
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/* 0 */ &sysrq_loglevel_op,
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/* 1 */ &sysrq_loglevel_op,
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/* 2 */ &sysrq_loglevel_op,
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/* 3 */ &sysrq_loglevel_op,
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/* 4 */ &sysrq_loglevel_op,
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/* 5 */ &sysrq_loglevel_op,
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/* 6 */ &sysrq_loglevel_op,
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/* 7 */ &sysrq_loglevel_op,
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/* 8 */ &sysrq_loglevel_op,
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/* 9 */ &sysrq_loglevel_op,
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/* a */ NULL, /* Don't use for system provided sysrqs,
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it is handled specially on the sparc
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and will never arrive */
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/* b */ &sysrq_reboot_op,
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#ifdef CONFIG_KEXEC
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/* c */ &sysrq_crashdump_op,
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#else
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/* c */ NULL,
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#endif
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/* d */ NULL,
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/* e */ &sysrq_term_op,
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/* f */ &sysrq_moom_op,
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/* g */ NULL,
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/* h */ NULL,
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/* i */ &sysrq_kill_op,
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/* j */ NULL,
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#ifdef CONFIG_VT
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/* k */ &sysrq_SAK_op,
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#else
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/* k */ NULL,
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#endif
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/* l */ NULL,
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/* m */ &sysrq_showmem_op,
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/* n */ &sysrq_unrt_op,
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/* o */ NULL, /* This will often be registered
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as 'Off' at init time */
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/* p */ &sysrq_showregs_op,
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/* q */ NULL,
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#ifdef CONFIG_VT
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/* r */ &sysrq_unraw_op,
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#else
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/* r */ NULL,
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#endif
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/* s */ &sysrq_sync_op,
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/* t */ &sysrq_showstate_op,
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/* u */ &sysrq_mountro_op,
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/* v */ NULL, /* May be assigned at init time by SMP VOYAGER */
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/* w */ NULL,
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/* x */ NULL,
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/* y */ NULL,
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/* z */ NULL
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};
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/* key2index calculation, -1 on invalid index */
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static int sysrq_key_table_key2index(int key) {
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int retval;
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if ((key >= '0') && (key <= '9')) {
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retval = key - '0';
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} else if ((key >= 'a') && (key <= 'z')) {
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retval = key + 10 - 'a';
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} else {
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retval = -1;
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}
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return retval;
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}
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/*
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* get and put functions for the table, exposed to modules.
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*/
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struct sysrq_key_op *__sysrq_get_key_op (int key) {
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struct sysrq_key_op *op_p;
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int i;
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i = sysrq_key_table_key2index(key);
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op_p = (i == -1) ? NULL : sysrq_key_table[i];
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return op_p;
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}
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static void __sysrq_put_key_op (int key, struct sysrq_key_op *op_p) {
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int i;
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i = sysrq_key_table_key2index(key);
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if (i != -1)
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sysrq_key_table[i] = op_p;
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}
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/*
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* This is the non-locking version of handle_sysrq
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* It must/can only be called by sysrq key handlers,
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* as they are inside of the lock
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*/
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void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty, int check_mask)
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{
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struct sysrq_key_op *op_p;
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int orig_log_level;
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int i, j;
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unsigned long flags;
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spin_lock_irqsave(&sysrq_key_table_lock, flags);
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orig_log_level = console_loglevel;
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console_loglevel = 7;
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printk(KERN_INFO "SysRq : ");
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op_p = __sysrq_get_key_op(key);
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if (op_p) {
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/* Should we check for enabled operations (/proc/sysrq-trigger should not)
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* and is the invoked operation enabled? */
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if (!check_mask || sysrq_enabled == 1 ||
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(sysrq_enabled & op_p->enable_mask)) {
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printk ("%s\n", op_p->action_msg);
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console_loglevel = orig_log_level;
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op_p->handler(key, pt_regs, tty);
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}
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else
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printk("This sysrq operation is disabled.\n");
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} else {
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printk("HELP : ");
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/* Only print the help msg once per handler */
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for (i=0; i<SYSRQ_KEY_TABLE_LENGTH; i++)
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if (sysrq_key_table[i]) {
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for (j=0; sysrq_key_table[i] != sysrq_key_table[j]; j++);
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if (j == i)
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printk ("%s ", sysrq_key_table[i]->help_msg);
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}
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printk ("\n");
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console_loglevel = orig_log_level;
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}
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spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
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}
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/*
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* This function is called by the keyboard handler when SysRq is pressed
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* and any other keycode arrives.
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*/
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void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
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{
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if (!sysrq_enabled)
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return;
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__handle_sysrq(key, pt_regs, tty, 1);
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}
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static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
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struct sysrq_key_op *remove_op_p) {
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int retval;
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unsigned long flags;
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spin_lock_irqsave(&sysrq_key_table_lock, flags);
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if (__sysrq_get_key_op(key) == remove_op_p) {
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__sysrq_put_key_op(key, insert_op_p);
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retval = 0;
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} else {
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retval = -1;
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}
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spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
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return retval;
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}
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int register_sysrq_key(int key, struct sysrq_key_op *op_p)
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{
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return __sysrq_swap_key_ops(key, op_p, NULL);
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}
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int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
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{
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return __sysrq_swap_key_ops(key, NULL, op_p);
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}
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EXPORT_SYMBOL(handle_sysrq);
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EXPORT_SYMBOL(register_sysrq_key);
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EXPORT_SYMBOL(unregister_sysrq_key);
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