1 /* -*- linux-c -*-
2 *
3 * $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
4 *
5 * Linux Magic System Request Key Hacks
6 *
7 * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
8 * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
9 */
10
11 #include <linux/config.h>
12 #include <linux/sched.h>
13 #include <linux/interrupt.h>
14 #include <linux/mm.h>
15 #include <linux/fs.h>
16 #include <linux/mount.h>
17 #include <linux/kdev_t.h>
18 #include <linux/major.h>
19 #include <linux/reboot.h>
20 #include <linux/sysrq.h>
21 #include <linux/kbd_kern.h>
22 #include <linux/quotaops.h>
23 #include <linux/smp_lock.h>
24 #include <linux/module.h>
25
26 #include <asm/ptrace.h>
27
28 extern void wakeup_bdflush(int);
29 extern void reset_vc(unsigned int);
30 extern struct list_head super_blocks;
31
32 /* Whether we react on sysrq keys or just ignore them */
33 int sysrq_enabled = 1;
34
35 /* Machine specific power off function */
36 void (*sysrq_power_off)(void);
37
38 EXPORT_SYMBOL(sysrq_power_off);
39
40 /* Send a signal to all user processes */
41
42 static void send_sig_all(int sig, int even_init)
43 {
44 struct task_struct *p;
45
46 for_each_task(p) {
47 if (p->mm) { /* Not swapper nor kernel thread */
48 if (p->pid == 1 && even_init) /* Ugly hack to kill init */
49 p->pid = 0x8000;
50 force_sig(sig, p);
51 }
52 }
53 }
54
55 /*
56 * This function is called by the keyboard handler when SysRq is pressed
57 * and any other keycode arrives.
58 */
59
60 void handle_sysrq(int key, struct pt_regs *pt_regs,
61 struct kbd_struct *kbd, struct tty_struct *tty)
62 {
63 int orig_log_level = console_loglevel;
64
65 if (!sysrq_enabled)
66 return;
67
68 if (!key)
69 return;
70
71 console_loglevel = 7;
72 printk(KERN_INFO "SysRq: ");
73 switch (key) {
74 case 'r': /* R -- Reset raw mode */
75 if (kbd) {
76 kbd->kbdmode = VC_XLATE;
77 printk("Keyboard mode set to XLATE\n");
78 }
79 break;
80 #ifdef CONFIG_VT
81 case 'k': /* K -- SAK */
82 printk("SAK\n");
83 if (tty)
84 do_SAK(tty);
85 reset_vc(fg_console);
86 break;
87 #endif
88 case 'b': /* B -- boot immediately */
89 printk("Resetting\n");
90 machine_restart(NULL);
91 break;
92 case 'o': /* O -- power off */
93 if (sysrq_power_off) {
94 printk("Power off\n");
95 sysrq_power_off();
96 }
97 break;
98 case 's': /* S -- emergency sync */
99 printk("Emergency Sync\n");
100 emergency_sync_scheduled = EMERG_SYNC;
101 wakeup_bdflush(0);
102 break;
103 case 'u': /* U -- emergency remount R/O */
104 printk("Emergency Remount R/O\n");
105 emergency_sync_scheduled = EMERG_REMOUNT;
106 wakeup_bdflush(0);
107 break;
108 case 'p': /* P -- show PC */
109 printk("Show Regs\n");
110 if (pt_regs)
111 show_regs(pt_regs);
112 break;
113 case 't': /* T -- show task info */
114 printk("Show State\n");
115 show_state();
116 break;
117 case 'm': /* M -- show memory info */
118 printk("Show Memory\n");
119 show_mem();
120 break;
121 case '' ... '9': /* 0-9 -- set console logging level */
122 orig_log_level = key - '';
123 printk("Log level set to %d\n", orig_log_level);
124 break;
125 case 'e': /* E -- terminate all user processes */
126 printk("Terminate All Tasks\n");
127 send_sig_all(SIGTERM, 0);
128 orig_log_level = 8; /* We probably have killed syslogd */
129 break;
130 case 'i': /* I -- kill all user processes */
131 printk("Kill All Tasks\n");
132 send_sig_all(SIGKILL, 0);
133 orig_log_level = 8;
134 break;
135 case 'l': /* L -- kill all processes including init */
136 printk("Kill ALL Tasks (even init)\n");
137 send_sig_all(SIGKILL, 1);
138 orig_log_level = 8;
139 break;
140 default: /* Unknown: help */
141 if (kbd)
142 printk("unRaw ");
143 #ifdef CONFIG_VT
144 if (tty)
145 printk("saK ");
146 #endif
147 printk("Boot ");
148 if (sysrq_power_off)
149 printk("Off ");
150 printk("Sync Unmount showPc showTasks showMem loglevel0-8 tErm kIll killalL\n");
151 /* Don't use 'A' as it's handled specially on the Sparc */
152 }
153
154 console_loglevel = orig_log_level;
155 }
156
157 /* Aux routines for the syncer */
158
159 static int is_local_disk(kdev_t dev) /* Guess if the device is a local hard drive */
160 {
161 unsigned int major = MAJOR(dev);
162
163 switch (major) {
164 case IDE0_MAJOR:
165 case IDE1_MAJOR:
166 case IDE2_MAJOR:
167 case IDE3_MAJOR:
168 case SCSI_DISK0_MAJOR:
169 case SCSI_DISK1_MAJOR:
170 case SCSI_DISK2_MAJOR:
171 case SCSI_DISK3_MAJOR:
172 case SCSI_DISK4_MAJOR:
173 case SCSI_DISK5_MAJOR:
174 case SCSI_DISK6_MAJOR:
175 case SCSI_DISK7_MAJOR:
176 return 1;
177 default:
178 return 0;
179 }
180 }
181
182 static void go_sync(struct super_block *sb, int remount_flag)
183 {
184 printk(KERN_INFO "%sing device %s ... ",
185 remount_flag ? "Remount" : "Sync",
186 kdevname(sb->s_dev));
187
188 if (remount_flag) { /* Remount R/O */
189 int ret, flags;
190 struct list_head *p;
191
192 if (sb->s_flags & MS_RDONLY) {
193 printk("R/O\n");
194 return;
195 }
196
197 file_list_lock();
198 for (p = sb->s_files.next; p != &sb->s_files; p = p->next) {
199 struct file *file = list_entry(p, struct file, f_list);
200 if (file->f_dentry && file_count(file)
201 && S_ISREG(file->f_dentry->d_inode->i_mode))
202 file->f_mode &= ~2;
203 }
204 file_list_unlock();
205 DQUOT_OFF(sb);
206 fsync_dev(sb->s_dev);
207 flags = MS_RDONLY;
208 if (sb->s_op && sb->s_op->remount_fs) {
209 ret = sb->s_op->remount_fs(sb, &flags, NULL);
210 if (ret)
211 printk("error %d\n", ret);
212 else {
213 sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
214 printk("OK\n");
215 }
216 } else
217 printk("nothing to do\n");
218 } else {
219 fsync_dev(sb->s_dev); /* Sync only */
220 printk("OK\n");
221 }
222 }
223
224 /*
225 * Emergency Sync or Unmount. We cannot do it directly, so we set a special
226 * flag and wake up the bdflush kernel thread which immediately calls this function.
227 * We process all mounted hard drives first to recover from crashed experimental
228 * block devices and malfunctional network filesystems.
229 */
230
231 int emergency_sync_scheduled;
232
233 void do_emergency_sync(void)
234 {
235 struct super_block *sb;
236 int remount_flag;
237
238 lock_kernel();
239 remount_flag = (emergency_sync_scheduled == EMERG_REMOUNT);
240 emergency_sync_scheduled = 0;
241
242 for (sb = sb_entry(super_blocks.next);
243 sb != sb_entry(&super_blocks);
244 sb = sb_entry(sb->s_list.next))
245 if (is_local_disk(sb->s_dev))
246 go_sync(sb, remount_flag);
247
248 for (sb = sb_entry(super_blocks.next);
249 sb != sb_entry(&super_blocks);
250 sb = sb_entry(sb->s_list.next))
251 if (!is_local_disk(sb->s_dev) && MAJOR(sb->s_dev))
252 go_sync(sb, remount_flag);
253
254 unlock_kernel();
255 printk(KERN_INFO "Done.\n");
256 }
257
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