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Commit | Line | Data |
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15d94b82 RH |
1 | /* |
2 | * linux/kernel/reboot.c | |
3 | * | |
4 | * Copyright (C) 2013 Linus Torvalds | |
5 | */ | |
6 | ||
972ee83d RH |
7 | #define pr_fmt(fmt) "reboot: " fmt |
8 | ||
1b3a5d02 | 9 | #include <linux/ctype.h> |
15d94b82 RH |
10 | #include <linux/export.h> |
11 | #include <linux/kexec.h> | |
12 | #include <linux/kmod.h> | |
13 | #include <linux/kmsg_dump.h> | |
14 | #include <linux/reboot.h> | |
15 | #include <linux/suspend.h> | |
16 | #include <linux/syscalls.h> | |
17 | #include <linux/syscore_ops.h> | |
18 | #include <linux/uaccess.h> | |
19 | ||
20 | /* | |
21 | * this indicates whether you can reboot with ctrl-alt-del: the default is yes | |
22 | */ | |
23 | ||
24 | int C_A_D = 1; | |
25 | struct pid *cad_pid; | |
26 | EXPORT_SYMBOL(cad_pid); | |
27 | ||
1b3a5d02 RH |
28 | #if defined(CONFIG_ARM) || defined(CONFIG_UNICORE32) |
29 | #define DEFAULT_REBOOT_MODE = REBOOT_HARD | |
30 | #else | |
31 | #define DEFAULT_REBOOT_MODE | |
32 | #endif | |
33 | enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE; | |
b287a25a | 34 | enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED; |
1b3a5d02 | 35 | |
e2f0b88e CL |
36 | /* |
37 | * This variable is used privately to keep track of whether or not | |
38 | * reboot_type is still set to its default value (i.e., reboot= hasn't | |
39 | * been set on the command line). This is needed so that we can | |
40 | * suppress DMI scanning for reboot quirks. Without it, it's | |
41 | * impossible to override a faulty reboot quirk without recompiling. | |
42 | */ | |
43 | int reboot_default = 1; | |
1b3a5d02 RH |
44 | int reboot_cpu; |
45 | enum reboot_type reboot_type = BOOT_ACPI; | |
46 | int reboot_force; | |
47 | ||
15d94b82 RH |
48 | /* |
49 | * If set, this is used for preparing the system to power off. | |
50 | */ | |
51 | ||
52 | void (*pm_power_off_prepare)(void); | |
74f008f2 | 53 | EXPORT_SYMBOL_GPL(pm_power_off_prepare); |
15d94b82 RH |
54 | |
55 | /** | |
56 | * emergency_restart - reboot the system | |
57 | * | |
58 | * Without shutting down any hardware or taking any locks | |
59 | * reboot the system. This is called when we know we are in | |
60 | * trouble so this is our best effort to reboot. This is | |
61 | * safe to call in interrupt context. | |
62 | */ | |
63 | void emergency_restart(void) | |
64 | { | |
65 | kmsg_dump(KMSG_DUMP_EMERG); | |
66 | machine_emergency_restart(); | |
67 | } | |
68 | EXPORT_SYMBOL_GPL(emergency_restart); | |
69 | ||
70 | void kernel_restart_prepare(char *cmd) | |
71 | { | |
72 | blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
73 | system_state = SYSTEM_RESTART; | |
74 | usermodehelper_disable(); | |
75 | device_shutdown(); | |
76 | } | |
77 | ||
78 | /** | |
79 | * register_reboot_notifier - Register function to be called at reboot time | |
80 | * @nb: Info about notifier function to be called | |
81 | * | |
82 | * Registers a function with the list of functions | |
83 | * to be called at reboot time. | |
84 | * | |
85 | * Currently always returns zero, as blocking_notifier_chain_register() | |
86 | * always returns zero. | |
87 | */ | |
88 | int register_reboot_notifier(struct notifier_block *nb) | |
89 | { | |
90 | return blocking_notifier_chain_register(&reboot_notifier_list, nb); | |
91 | } | |
92 | EXPORT_SYMBOL(register_reboot_notifier); | |
93 | ||
94 | /** | |
95 | * unregister_reboot_notifier - Unregister previously registered reboot notifier | |
96 | * @nb: Hook to be unregistered | |
97 | * | |
98 | * Unregisters a previously registered reboot | |
99 | * notifier function. | |
100 | * | |
101 | * Returns zero on success, or %-ENOENT on failure. | |
102 | */ | |
103 | int unregister_reboot_notifier(struct notifier_block *nb) | |
104 | { | |
105 | return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); | |
106 | } | |
107 | EXPORT_SYMBOL(unregister_reboot_notifier); | |
108 | ||
2d8364ba AS |
109 | static void devm_unregister_reboot_notifier(struct device *dev, void *res) |
110 | { | |
111 | WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res)); | |
112 | } | |
113 | ||
114 | int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb) | |
115 | { | |
116 | struct notifier_block **rcnb; | |
117 | int ret; | |
118 | ||
119 | rcnb = devres_alloc(devm_unregister_reboot_notifier, | |
120 | sizeof(*rcnb), GFP_KERNEL); | |
121 | if (!rcnb) | |
122 | return -ENOMEM; | |
123 | ||
124 | ret = register_reboot_notifier(nb); | |
125 | if (!ret) { | |
126 | *rcnb = nb; | |
127 | devres_add(dev, rcnb); | |
128 | } else { | |
129 | devres_free(rcnb); | |
130 | } | |
131 | ||
132 | return ret; | |
133 | } | |
134 | EXPORT_SYMBOL(devm_register_reboot_notifier); | |
135 | ||
b63adb97 GR |
136 | /* |
137 | * Notifier list for kernel code which wants to be called | |
138 | * to restart the system. | |
139 | */ | |
140 | static ATOMIC_NOTIFIER_HEAD(restart_handler_list); | |
141 | ||
142 | /** | |
143 | * register_restart_handler - Register function to be called to reset | |
144 | * the system | |
145 | * @nb: Info about handler function to be called | |
146 | * @nb->priority: Handler priority. Handlers should follow the | |
147 | * following guidelines for setting priorities. | |
148 | * 0: Restart handler of last resort, | |
149 | * with limited restart capabilities | |
150 | * 128: Default restart handler; use if no other | |
151 | * restart handler is expected to be available, | |
152 | * and/or if restart functionality is | |
153 | * sufficient to restart the entire system | |
154 | * 255: Highest priority restart handler, will | |
155 | * preempt all other restart handlers | |
156 | * | |
157 | * Registers a function with code to be called to restart the | |
158 | * system. | |
159 | * | |
160 | * Registered functions will be called from machine_restart as last | |
161 | * step of the restart sequence (if the architecture specific | |
162 | * machine_restart function calls do_kernel_restart - see below | |
163 | * for details). | |
164 | * Registered functions are expected to restart the system immediately. | |
165 | * If more than one function is registered, the restart handler priority | |
166 | * selects which function will be called first. | |
167 | * | |
168 | * Restart handlers are expected to be registered from non-architecture | |
169 | * code, typically from drivers. A typical use case would be a system | |
170 | * where restart functionality is provided through a watchdog. Multiple | |
171 | * restart handlers may exist; for example, one restart handler might | |
172 | * restart the entire system, while another only restarts the CPU. | |
173 | * In such cases, the restart handler which only restarts part of the | |
174 | * hardware is expected to register with low priority to ensure that | |
175 | * it only runs if no other means to restart the system is available. | |
176 | * | |
177 | * Currently always returns zero, as atomic_notifier_chain_register() | |
178 | * always returns zero. | |
179 | */ | |
180 | int register_restart_handler(struct notifier_block *nb) | |
181 | { | |
182 | return atomic_notifier_chain_register(&restart_handler_list, nb); | |
183 | } | |
184 | EXPORT_SYMBOL(register_restart_handler); | |
185 | ||
186 | /** | |
187 | * unregister_restart_handler - Unregister previously registered | |
188 | * restart handler | |
189 | * @nb: Hook to be unregistered | |
190 | * | |
191 | * Unregisters a previously registered restart handler function. | |
192 | * | |
193 | * Returns zero on success, or %-ENOENT on failure. | |
194 | */ | |
195 | int unregister_restart_handler(struct notifier_block *nb) | |
196 | { | |
197 | return atomic_notifier_chain_unregister(&restart_handler_list, nb); | |
198 | } | |
199 | EXPORT_SYMBOL(unregister_restart_handler); | |
200 | ||
201 | /** | |
202 | * do_kernel_restart - Execute kernel restart handler call chain | |
203 | * | |
204 | * Calls functions registered with register_restart_handler. | |
205 | * | |
206 | * Expected to be called from machine_restart as last step of the restart | |
207 | * sequence. | |
208 | * | |
209 | * Restarts the system immediately if a restart handler function has been | |
210 | * registered. Otherwise does nothing. | |
211 | */ | |
212 | void do_kernel_restart(char *cmd) | |
213 | { | |
214 | atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd); | |
215 | } | |
216 | ||
c97102ba | 217 | void migrate_to_reboot_cpu(void) |
15d94b82 RH |
218 | { |
219 | /* The boot cpu is always logical cpu 0 */ | |
1b3a5d02 | 220 | int cpu = reboot_cpu; |
15d94b82 RH |
221 | |
222 | cpu_hotplug_disable(); | |
223 | ||
224 | /* Make certain the cpu I'm about to reboot on is online */ | |
225 | if (!cpu_online(cpu)) | |
226 | cpu = cpumask_first(cpu_online_mask); | |
227 | ||
228 | /* Prevent races with other tasks migrating this task */ | |
229 | current->flags |= PF_NO_SETAFFINITY; | |
230 | ||
231 | /* Make certain I only run on the appropriate processor */ | |
232 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); | |
233 | } | |
234 | ||
235 | /** | |
236 | * kernel_restart - reboot the system | |
237 | * @cmd: pointer to buffer containing command to execute for restart | |
238 | * or %NULL | |
239 | * | |
240 | * Shutdown everything and perform a clean reboot. | |
241 | * This is not safe to call in interrupt context. | |
242 | */ | |
243 | void kernel_restart(char *cmd) | |
244 | { | |
245 | kernel_restart_prepare(cmd); | |
246 | migrate_to_reboot_cpu(); | |
247 | syscore_shutdown(); | |
248 | if (!cmd) | |
972ee83d | 249 | pr_emerg("Restarting system\n"); |
15d94b82 | 250 | else |
972ee83d | 251 | pr_emerg("Restarting system with command '%s'\n", cmd); |
15d94b82 RH |
252 | kmsg_dump(KMSG_DUMP_RESTART); |
253 | machine_restart(cmd); | |
254 | } | |
255 | EXPORT_SYMBOL_GPL(kernel_restart); | |
256 | ||
257 | static void kernel_shutdown_prepare(enum system_states state) | |
258 | { | |
259 | blocking_notifier_call_chain(&reboot_notifier_list, | |
972ee83d | 260 | (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL); |
15d94b82 RH |
261 | system_state = state; |
262 | usermodehelper_disable(); | |
263 | device_shutdown(); | |
264 | } | |
265 | /** | |
266 | * kernel_halt - halt the system | |
267 | * | |
268 | * Shutdown everything and perform a clean system halt. | |
269 | */ | |
270 | void kernel_halt(void) | |
271 | { | |
272 | kernel_shutdown_prepare(SYSTEM_HALT); | |
273 | migrate_to_reboot_cpu(); | |
274 | syscore_shutdown(); | |
972ee83d | 275 | pr_emerg("System halted\n"); |
15d94b82 RH |
276 | kmsg_dump(KMSG_DUMP_HALT); |
277 | machine_halt(); | |
278 | } | |
15d94b82 RH |
279 | EXPORT_SYMBOL_GPL(kernel_halt); |
280 | ||
281 | /** | |
282 | * kernel_power_off - power_off the system | |
283 | * | |
284 | * Shutdown everything and perform a clean system power_off. | |
285 | */ | |
286 | void kernel_power_off(void) | |
287 | { | |
288 | kernel_shutdown_prepare(SYSTEM_POWER_OFF); | |
289 | if (pm_power_off_prepare) | |
290 | pm_power_off_prepare(); | |
291 | migrate_to_reboot_cpu(); | |
292 | syscore_shutdown(); | |
972ee83d | 293 | pr_emerg("Power down\n"); |
15d94b82 RH |
294 | kmsg_dump(KMSG_DUMP_POWEROFF); |
295 | machine_power_off(); | |
296 | } | |
297 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
298 | ||
55f2503c | 299 | DEFINE_MUTEX(system_transition_mutex); |
15d94b82 RH |
300 | |
301 | /* | |
302 | * Reboot system call: for obvious reasons only root may call it, | |
303 | * and even root needs to set up some magic numbers in the registers | |
304 | * so that some mistake won't make this reboot the whole machine. | |
305 | * You can also set the meaning of the ctrl-alt-del-key here. | |
306 | * | |
307 | * reboot doesn't sync: do that yourself before calling this. | |
308 | */ | |
309 | SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, | |
310 | void __user *, arg) | |
311 | { | |
312 | struct pid_namespace *pid_ns = task_active_pid_ns(current); | |
313 | char buffer[256]; | |
314 | int ret = 0; | |
315 | ||
316 | /* We only trust the superuser with rebooting the system. */ | |
317 | if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT)) | |
318 | return -EPERM; | |
319 | ||
320 | /* For safety, we require "magic" arguments. */ | |
321 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
972ee83d RH |
322 | (magic2 != LINUX_REBOOT_MAGIC2 && |
323 | magic2 != LINUX_REBOOT_MAGIC2A && | |
15d94b82 | 324 | magic2 != LINUX_REBOOT_MAGIC2B && |
972ee83d | 325 | magic2 != LINUX_REBOOT_MAGIC2C)) |
15d94b82 RH |
326 | return -EINVAL; |
327 | ||
328 | /* | |
329 | * If pid namespaces are enabled and the current task is in a child | |
330 | * pid_namespace, the command is handled by reboot_pid_ns() which will | |
331 | * call do_exit(). | |
332 | */ | |
333 | ret = reboot_pid_ns(pid_ns, cmd); | |
334 | if (ret) | |
335 | return ret; | |
336 | ||
337 | /* Instead of trying to make the power_off code look like | |
338 | * halt when pm_power_off is not set do it the easy way. | |
339 | */ | |
340 | if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) | |
341 | cmd = LINUX_REBOOT_CMD_HALT; | |
342 | ||
55f2503c | 343 | mutex_lock(&system_transition_mutex); |
15d94b82 RH |
344 | switch (cmd) { |
345 | case LINUX_REBOOT_CMD_RESTART: | |
346 | kernel_restart(NULL); | |
347 | break; | |
348 | ||
349 | case LINUX_REBOOT_CMD_CAD_ON: | |
350 | C_A_D = 1; | |
351 | break; | |
352 | ||
353 | case LINUX_REBOOT_CMD_CAD_OFF: | |
354 | C_A_D = 0; | |
355 | break; | |
356 | ||
357 | case LINUX_REBOOT_CMD_HALT: | |
358 | kernel_halt(); | |
359 | do_exit(0); | |
360 | panic("cannot halt"); | |
361 | ||
362 | case LINUX_REBOOT_CMD_POWER_OFF: | |
363 | kernel_power_off(); | |
364 | do_exit(0); | |
365 | break; | |
366 | ||
367 | case LINUX_REBOOT_CMD_RESTART2: | |
972ee83d RH |
368 | ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1); |
369 | if (ret < 0) { | |
15d94b82 RH |
370 | ret = -EFAULT; |
371 | break; | |
372 | } | |
373 | buffer[sizeof(buffer) - 1] = '\0'; | |
374 | ||
375 | kernel_restart(buffer); | |
376 | break; | |
377 | ||
2965faa5 | 378 | #ifdef CONFIG_KEXEC_CORE |
15d94b82 RH |
379 | case LINUX_REBOOT_CMD_KEXEC: |
380 | ret = kernel_kexec(); | |
381 | break; | |
382 | #endif | |
383 | ||
384 | #ifdef CONFIG_HIBERNATION | |
385 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
386 | ret = hibernate(); | |
387 | break; | |
388 | #endif | |
389 | ||
390 | default: | |
391 | ret = -EINVAL; | |
392 | break; | |
393 | } | |
55f2503c | 394 | mutex_unlock(&system_transition_mutex); |
15d94b82 RH |
395 | return ret; |
396 | } | |
397 | ||
398 | static void deferred_cad(struct work_struct *dummy) | |
399 | { | |
400 | kernel_restart(NULL); | |
401 | } | |
402 | ||
403 | /* | |
404 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
405 | * As it's called within an interrupt, it may NOT sync: the only choice | |
406 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
407 | */ | |
408 | void ctrl_alt_del(void) | |
409 | { | |
410 | static DECLARE_WORK(cad_work, deferred_cad); | |
411 | ||
412 | if (C_A_D) | |
413 | schedule_work(&cad_work); | |
414 | else | |
415 | kill_cad_pid(SIGINT, 1); | |
416 | } | |
417 | ||
418 | char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; | |
7a54f46b | 419 | static const char reboot_cmd[] = "/sbin/reboot"; |
15d94b82 | 420 | |
7a54f46b | 421 | static int run_cmd(const char *cmd) |
15d94b82 RH |
422 | { |
423 | char **argv; | |
424 | static char *envp[] = { | |
425 | "HOME=/", | |
426 | "PATH=/sbin:/bin:/usr/sbin:/usr/bin", | |
427 | NULL | |
428 | }; | |
429 | int ret; | |
7a54f46b | 430 | argv = argv_split(GFP_KERNEL, cmd, NULL); |
15d94b82 RH |
431 | if (argv) { |
432 | ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); | |
433 | argv_free(argv); | |
434 | } else { | |
15d94b82 RH |
435 | ret = -ENOMEM; |
436 | } | |
437 | ||
7a54f46b JS |
438 | return ret; |
439 | } | |
440 | ||
441 | static int __orderly_reboot(void) | |
442 | { | |
443 | int ret; | |
444 | ||
445 | ret = run_cmd(reboot_cmd); | |
446 | ||
447 | if (ret) { | |
448 | pr_warn("Failed to start orderly reboot: forcing the issue\n"); | |
449 | emergency_sync(); | |
450 | kernel_restart(NULL); | |
451 | } | |
452 | ||
453 | return ret; | |
454 | } | |
455 | ||
456 | static int __orderly_poweroff(bool force) | |
457 | { | |
458 | int ret; | |
459 | ||
460 | ret = run_cmd(poweroff_cmd); | |
461 | ||
15d94b82 | 462 | if (ret && force) { |
972ee83d | 463 | pr_warn("Failed to start orderly shutdown: forcing the issue\n"); |
7a54f46b | 464 | |
15d94b82 RH |
465 | /* |
466 | * I guess this should try to kick off some daemon to sync and | |
467 | * poweroff asap. Or not even bother syncing if we're doing an | |
468 | * emergency shutdown? | |
469 | */ | |
470 | emergency_sync(); | |
471 | kernel_power_off(); | |
472 | } | |
473 | ||
474 | return ret; | |
475 | } | |
476 | ||
477 | static bool poweroff_force; | |
478 | ||
479 | static void poweroff_work_func(struct work_struct *work) | |
480 | { | |
481 | __orderly_poweroff(poweroff_force); | |
482 | } | |
483 | ||
484 | static DECLARE_WORK(poweroff_work, poweroff_work_func); | |
485 | ||
486 | /** | |
487 | * orderly_poweroff - Trigger an orderly system poweroff | |
488 | * @force: force poweroff if command execution fails | |
489 | * | |
490 | * This may be called from any context to trigger a system shutdown. | |
491 | * If the orderly shutdown fails, it will force an immediate shutdown. | |
492 | */ | |
7a54f46b | 493 | void orderly_poweroff(bool force) |
15d94b82 RH |
494 | { |
495 | if (force) /* do not override the pending "true" */ | |
496 | poweroff_force = true; | |
497 | schedule_work(&poweroff_work); | |
15d94b82 RH |
498 | } |
499 | EXPORT_SYMBOL_GPL(orderly_poweroff); | |
1b3a5d02 | 500 | |
7a54f46b JS |
501 | static void reboot_work_func(struct work_struct *work) |
502 | { | |
503 | __orderly_reboot(); | |
504 | } | |
505 | ||
506 | static DECLARE_WORK(reboot_work, reboot_work_func); | |
507 | ||
508 | /** | |
509 | * orderly_reboot - Trigger an orderly system reboot | |
510 | * | |
511 | * This may be called from any context to trigger a system reboot. | |
512 | * If the orderly reboot fails, it will force an immediate reboot. | |
513 | */ | |
514 | void orderly_reboot(void) | |
515 | { | |
516 | schedule_work(&reboot_work); | |
517 | } | |
518 | EXPORT_SYMBOL_GPL(orderly_reboot); | |
519 | ||
1b3a5d02 RH |
520 | static int __init reboot_setup(char *str) |
521 | { | |
522 | for (;;) { | |
b287a25a AK |
523 | enum reboot_mode *mode; |
524 | ||
1b3a5d02 RH |
525 | /* |
526 | * Having anything passed on the command line via | |
527 | * reboot= will cause us to disable DMI checking | |
528 | * below. | |
529 | */ | |
530 | reboot_default = 0; | |
531 | ||
b287a25a AK |
532 | if (!strncmp(str, "panic_", 6)) { |
533 | mode = &panic_reboot_mode; | |
534 | str += 6; | |
535 | } else { | |
536 | mode = &reboot_mode; | |
537 | } | |
538 | ||
1b3a5d02 RH |
539 | switch (*str) { |
540 | case 'w': | |
b287a25a | 541 | *mode = REBOOT_WARM; |
1b3a5d02 RH |
542 | break; |
543 | ||
544 | case 'c': | |
b287a25a | 545 | *mode = REBOOT_COLD; |
1b3a5d02 RH |
546 | break; |
547 | ||
548 | case 'h': | |
b287a25a | 549 | *mode = REBOOT_HARD; |
1b3a5d02 RH |
550 | break; |
551 | ||
552 | case 's': | |
616feab7 FF |
553 | { |
554 | int rc; | |
555 | ||
556 | if (isdigit(*(str+1))) { | |
557 | rc = kstrtoint(str+1, 0, &reboot_cpu); | |
558 | if (rc) | |
559 | return rc; | |
560 | } else if (str[1] == 'm' && str[2] == 'p' && | |
561 | isdigit(*(str+3))) { | |
562 | rc = kstrtoint(str+3, 0, &reboot_cpu); | |
563 | if (rc) | |
564 | return rc; | |
565 | } else | |
b287a25a | 566 | *mode = REBOOT_SOFT; |
1b3a5d02 | 567 | break; |
616feab7 | 568 | } |
1b3a5d02 | 569 | case 'g': |
b287a25a | 570 | *mode = REBOOT_GPIO; |
1b3a5d02 RH |
571 | break; |
572 | ||
573 | case 'b': | |
574 | case 'a': | |
575 | case 'k': | |
576 | case 't': | |
577 | case 'e': | |
578 | case 'p': | |
579 | reboot_type = *str; | |
580 | break; | |
581 | ||
582 | case 'f': | |
583 | reboot_force = 1; | |
584 | break; | |
585 | } | |
586 | ||
587 | str = strchr(str, ','); | |
588 | if (str) | |
589 | str++; | |
590 | else | |
591 | break; | |
592 | } | |
593 | return 1; | |
594 | } | |
595 | __setup("reboot=", reboot_setup); |