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1da177e4 LT |
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 | * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com> | |
11 | * overhauled to use key registration | |
12 | * based upon discusions in irc://irc.openprojects.net/#kernelnewbies | |
13 | */ | |
14 | ||
15 | #include <linux/config.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/fs.h> | |
20 | #include <linux/tty.h> | |
21 | #include <linux/mount.h> | |
22 | #include <linux/kdev_t.h> | |
23 | #include <linux/major.h> | |
24 | #include <linux/reboot.h> | |
25 | #include <linux/sysrq.h> | |
26 | #include <linux/kbd_kern.h> | |
27 | #include <linux/quotaops.h> | |
28 | #include <linux/smp_lock.h> | |
29 | #include <linux/kernel.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/suspend.h> | |
32 | #include <linux/writeback.h> | |
33 | #include <linux/buffer_head.h> /* for fsync_bdev() */ | |
34 | #include <linux/swap.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/vt_kern.h> | |
37 | #include <linux/workqueue.h> | |
38 | ||
39 | #include <asm/ptrace.h> | |
40 | ||
41 | /* Whether we react on sysrq keys or just ignore them */ | |
42 | int sysrq_enabled = 1; | |
43 | ||
44 | /* Loglevel sysrq handler */ | |
45 | static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs, | |
46 | struct tty_struct *tty) | |
47 | { | |
48 | int i; | |
49 | i = key - '0'; | |
50 | console_loglevel = 7; | |
51 | printk("Loglevel set to %d\n", i); | |
52 | console_loglevel = i; | |
53 | } | |
54 | static struct sysrq_key_op sysrq_loglevel_op = { | |
55 | .handler = sysrq_handle_loglevel, | |
56 | .help_msg = "loglevel0-8", | |
57 | .action_msg = "Changing Loglevel", | |
58 | .enable_mask = SYSRQ_ENABLE_LOG, | |
59 | }; | |
60 | ||
61 | ||
62 | /* SAK sysrq handler */ | |
63 | #ifdef CONFIG_VT | |
64 | static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs, | |
65 | struct tty_struct *tty) | |
66 | { | |
67 | if (tty) | |
68 | do_SAK(tty); | |
69 | reset_vc(vc_cons[fg_console].d); | |
70 | } | |
71 | static struct sysrq_key_op sysrq_SAK_op = { | |
72 | .handler = sysrq_handle_SAK, | |
73 | .help_msg = "saK", | |
74 | .action_msg = "SAK", | |
75 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
76 | }; | |
77 | #endif | |
78 | ||
79 | #ifdef CONFIG_VT | |
80 | /* unraw sysrq handler */ | |
81 | static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs, | |
82 | struct tty_struct *tty) | |
83 | { | |
84 | struct kbd_struct *kbd = &kbd_table[fg_console]; | |
85 | ||
86 | if (kbd) | |
87 | kbd->kbdmode = VC_XLATE; | |
88 | } | |
89 | static struct sysrq_key_op sysrq_unraw_op = { | |
90 | .handler = sysrq_handle_unraw, | |
91 | .help_msg = "unRaw", | |
92 | .action_msg = "Keyboard mode set to XLATE", | |
93 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
94 | }; | |
95 | #endif /* CONFIG_VT */ | |
96 | ||
97 | /* reboot sysrq handler */ | |
98 | static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs, | |
99 | struct tty_struct *tty) | |
100 | { | |
101 | local_irq_enable(); | |
102 | machine_restart(NULL); | |
103 | } | |
104 | ||
105 | static struct sysrq_key_op sysrq_reboot_op = { | |
106 | .handler = sysrq_handle_reboot, | |
107 | .help_msg = "reBoot", | |
108 | .action_msg = "Resetting", | |
109 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
110 | }; | |
111 | ||
112 | static void sysrq_handle_sync(int key, struct pt_regs *pt_regs, | |
113 | struct tty_struct *tty) | |
114 | { | |
115 | emergency_sync(); | |
116 | } | |
117 | ||
118 | static struct sysrq_key_op sysrq_sync_op = { | |
119 | .handler = sysrq_handle_sync, | |
120 | .help_msg = "Sync", | |
121 | .action_msg = "Emergency Sync", | |
122 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
123 | }; | |
124 | ||
125 | static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs, | |
126 | struct tty_struct *tty) | |
127 | { | |
128 | emergency_remount(); | |
129 | } | |
130 | ||
131 | static struct sysrq_key_op sysrq_mountro_op = { | |
132 | .handler = sysrq_handle_mountro, | |
133 | .help_msg = "Unmount", | |
134 | .action_msg = "Emergency Remount R/O", | |
135 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
136 | }; | |
137 | ||
138 | /* END SYNC SYSRQ HANDLERS BLOCK */ | |
139 | ||
140 | ||
141 | /* SHOW SYSRQ HANDLERS BLOCK */ | |
142 | ||
143 | static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs, | |
144 | struct tty_struct *tty) | |
145 | { | |
146 | if (pt_regs) | |
147 | show_regs(pt_regs); | |
148 | } | |
149 | static struct sysrq_key_op sysrq_showregs_op = { | |
150 | .handler = sysrq_handle_showregs, | |
151 | .help_msg = "showPc", | |
152 | .action_msg = "Show Regs", | |
153 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
154 | }; | |
155 | ||
156 | ||
157 | static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs, | |
158 | struct tty_struct *tty) | |
159 | { | |
160 | show_state(); | |
161 | } | |
162 | static struct sysrq_key_op sysrq_showstate_op = { | |
163 | .handler = sysrq_handle_showstate, | |
164 | .help_msg = "showTasks", | |
165 | .action_msg = "Show State", | |
166 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
167 | }; | |
168 | ||
169 | ||
170 | static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs, | |
171 | struct tty_struct *tty) | |
172 | { | |
173 | show_mem(); | |
174 | } | |
175 | static struct sysrq_key_op sysrq_showmem_op = { | |
176 | .handler = sysrq_handle_showmem, | |
177 | .help_msg = "showMem", | |
178 | .action_msg = "Show Memory", | |
179 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
180 | }; | |
181 | ||
182 | /* SHOW SYSRQ HANDLERS BLOCK */ | |
183 | ||
184 | ||
185 | /* SIGNAL SYSRQ HANDLERS BLOCK */ | |
186 | ||
187 | /* signal sysrq helper function | |
188 | * Sends a signal to all user processes */ | |
189 | static void send_sig_all(int sig) | |
190 | { | |
191 | struct task_struct *p; | |
192 | ||
193 | for_each_process(p) { | |
194 | if (p->mm && p->pid != 1) | |
195 | /* Not swapper, init nor kernel thread */ | |
196 | force_sig(sig, p); | |
197 | } | |
198 | } | |
199 | ||
200 | static void sysrq_handle_term(int key, struct pt_regs *pt_regs, | |
201 | struct tty_struct *tty) | |
202 | { | |
203 | send_sig_all(SIGTERM); | |
204 | console_loglevel = 8; | |
205 | } | |
206 | static struct sysrq_key_op sysrq_term_op = { | |
207 | .handler = sysrq_handle_term, | |
208 | .help_msg = "tErm", | |
209 | .action_msg = "Terminate All Tasks", | |
210 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
211 | }; | |
212 | ||
213 | static void moom_callback(void *ignored) | |
214 | { | |
215 | out_of_memory(GFP_KERNEL); | |
216 | } | |
217 | ||
218 | static DECLARE_WORK(moom_work, moom_callback, NULL); | |
219 | ||
220 | static void sysrq_handle_moom(int key, struct pt_regs *pt_regs, | |
221 | struct tty_struct *tty) | |
222 | { | |
223 | schedule_work(&moom_work); | |
224 | } | |
225 | static struct sysrq_key_op sysrq_moom_op = { | |
226 | .handler = sysrq_handle_moom, | |
227 | .help_msg = "Full", | |
228 | .action_msg = "Manual OOM execution", | |
229 | }; | |
230 | ||
231 | static void sysrq_handle_kill(int key, struct pt_regs *pt_regs, | |
232 | struct tty_struct *tty) | |
233 | { | |
234 | send_sig_all(SIGKILL); | |
235 | console_loglevel = 8; | |
236 | } | |
237 | static struct sysrq_key_op sysrq_kill_op = { | |
238 | .handler = sysrq_handle_kill, | |
239 | .help_msg = "kIll", | |
240 | .action_msg = "Kill All Tasks", | |
241 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
242 | }; | |
243 | ||
244 | /* END SIGNAL SYSRQ HANDLERS BLOCK */ | |
245 | ||
246 | static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs, | |
247 | struct tty_struct *tty) | |
248 | { | |
249 | normalize_rt_tasks(); | |
250 | } | |
251 | static struct sysrq_key_op sysrq_unrt_op = { | |
252 | .handler = sysrq_handle_unrt, | |
253 | .help_msg = "Nice", | |
254 | .action_msg = "Nice All RT Tasks", | |
255 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
256 | }; | |
257 | ||
258 | /* Key Operations table and lock */ | |
259 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
260 | #define SYSRQ_KEY_TABLE_LENGTH 36 | |
261 | static struct sysrq_key_op *sysrq_key_table[SYSRQ_KEY_TABLE_LENGTH] = { | |
262 | /* 0 */ &sysrq_loglevel_op, | |
263 | /* 1 */ &sysrq_loglevel_op, | |
264 | /* 2 */ &sysrq_loglevel_op, | |
265 | /* 3 */ &sysrq_loglevel_op, | |
266 | /* 4 */ &sysrq_loglevel_op, | |
267 | /* 5 */ &sysrq_loglevel_op, | |
268 | /* 6 */ &sysrq_loglevel_op, | |
269 | /* 7 */ &sysrq_loglevel_op, | |
270 | /* 8 */ &sysrq_loglevel_op, | |
271 | /* 9 */ &sysrq_loglevel_op, | |
272 | /* a */ NULL, /* Don't use for system provided sysrqs, | |
273 | it is handled specially on the sparc | |
274 | and will never arrive */ | |
275 | /* b */ &sysrq_reboot_op, | |
276 | /* c */ NULL, | |
277 | /* d */ NULL, | |
278 | /* e */ &sysrq_term_op, | |
279 | /* f */ &sysrq_moom_op, | |
280 | /* g */ NULL, | |
281 | /* h */ NULL, | |
282 | /* i */ &sysrq_kill_op, | |
283 | /* j */ NULL, | |
284 | #ifdef CONFIG_VT | |
285 | /* k */ &sysrq_SAK_op, | |
286 | #else | |
287 | /* k */ NULL, | |
288 | #endif | |
289 | /* l */ NULL, | |
290 | /* m */ &sysrq_showmem_op, | |
291 | /* n */ &sysrq_unrt_op, | |
292 | /* o */ NULL, /* This will often be registered | |
293 | as 'Off' at init time */ | |
294 | /* p */ &sysrq_showregs_op, | |
295 | /* q */ NULL, | |
296 | #ifdef CONFIG_VT | |
297 | /* r */ &sysrq_unraw_op, | |
298 | #else | |
299 | /* r */ NULL, | |
300 | #endif | |
301 | /* s */ &sysrq_sync_op, | |
302 | /* t */ &sysrq_showstate_op, | |
303 | /* u */ &sysrq_mountro_op, | |
304 | /* v */ NULL, /* May be assigned at init time by SMP VOYAGER */ | |
305 | /* w */ NULL, | |
306 | /* x */ NULL, | |
307 | /* y */ NULL, | |
308 | /* z */ NULL | |
309 | }; | |
310 | ||
311 | /* key2index calculation, -1 on invalid index */ | |
312 | static int sysrq_key_table_key2index(int key) { | |
313 | int retval; | |
314 | if ((key >= '0') && (key <= '9')) { | |
315 | retval = key - '0'; | |
316 | } else if ((key >= 'a') && (key <= 'z')) { | |
317 | retval = key + 10 - 'a'; | |
318 | } else { | |
319 | retval = -1; | |
320 | } | |
321 | return retval; | |
322 | } | |
323 | ||
324 | /* | |
325 | * get and put functions for the table, exposed to modules. | |
326 | */ | |
327 | ||
328 | struct sysrq_key_op *__sysrq_get_key_op (int key) { | |
329 | struct sysrq_key_op *op_p; | |
330 | int i; | |
331 | ||
332 | i = sysrq_key_table_key2index(key); | |
333 | op_p = (i == -1) ? NULL : sysrq_key_table[i]; | |
334 | return op_p; | |
335 | } | |
336 | ||
337 | void __sysrq_put_key_op (int key, struct sysrq_key_op *op_p) { | |
338 | int i; | |
339 | ||
340 | i = sysrq_key_table_key2index(key); | |
341 | if (i != -1) | |
342 | sysrq_key_table[i] = op_p; | |
343 | } | |
344 | ||
345 | /* | |
346 | * This is the non-locking version of handle_sysrq | |
347 | * It must/can only be called by sysrq key handlers, | |
348 | * as they are inside of the lock | |
349 | */ | |
350 | ||
351 | void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty, int check_mask) | |
352 | { | |
353 | struct sysrq_key_op *op_p; | |
354 | int orig_log_level; | |
355 | int i, j; | |
356 | unsigned long flags; | |
357 | ||
358 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
359 | orig_log_level = console_loglevel; | |
360 | console_loglevel = 7; | |
361 | printk(KERN_INFO "SysRq : "); | |
362 | ||
363 | op_p = __sysrq_get_key_op(key); | |
364 | if (op_p) { | |
365 | /* Should we check for enabled operations (/proc/sysrq-trigger should not) | |
366 | * and is the invoked operation enabled? */ | |
367 | if (!check_mask || sysrq_enabled == 1 || | |
368 | (sysrq_enabled & op_p->enable_mask)) { | |
369 | printk ("%s\n", op_p->action_msg); | |
370 | console_loglevel = orig_log_level; | |
371 | op_p->handler(key, pt_regs, tty); | |
372 | } | |
373 | else | |
374 | printk("This sysrq operation is disabled.\n"); | |
375 | } else { | |
376 | printk("HELP : "); | |
377 | /* Only print the help msg once per handler */ | |
378 | for (i=0; i<SYSRQ_KEY_TABLE_LENGTH; i++) | |
379 | if (sysrq_key_table[i]) { | |
380 | for (j=0; sysrq_key_table[i] != sysrq_key_table[j]; j++); | |
381 | if (j == i) | |
382 | printk ("%s ", sysrq_key_table[i]->help_msg); | |
383 | } | |
384 | printk ("\n"); | |
385 | console_loglevel = orig_log_level; | |
386 | } | |
387 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
388 | } | |
389 | ||
390 | /* | |
391 | * This function is called by the keyboard handler when SysRq is pressed | |
392 | * and any other keycode arrives. | |
393 | */ | |
394 | ||
395 | void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty) | |
396 | { | |
397 | if (!sysrq_enabled) | |
398 | return; | |
399 | __handle_sysrq(key, pt_regs, tty, 1); | |
400 | } | |
401 | ||
402 | int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, | |
403 | struct sysrq_key_op *remove_op_p) { | |
404 | ||
405 | int retval; | |
406 | unsigned long flags; | |
407 | ||
408 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
409 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
410 | __sysrq_put_key_op(key, insert_op_p); | |
411 | retval = 0; | |
412 | } else { | |
413 | retval = -1; | |
414 | } | |
415 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
416 | ||
417 | return retval; | |
418 | } | |
419 | ||
420 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
421 | { | |
422 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
423 | } | |
424 | ||
425 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
426 | { | |
427 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
428 | } | |
429 | ||
430 | EXPORT_SYMBOL(handle_sysrq); | |
431 | EXPORT_SYMBOL(register_sysrq_key); | |
432 | EXPORT_SYMBOL(unregister_sysrq_key); |