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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
4 * Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
5 */
6
7#include <linux/console.h>
8#include <linux/ctype.h>
9#include <linux/string.h>
10#include <linux/interrupt.h>
11#include <linux/list.h>
12#include <linux/mm.h>
13#include <linux/module.h>
14#include <linux/notifier.h>
15#include <linux/panic_notifier.h>
16#include <linux/reboot.h>
17#include <linux/sched/debug.h>
18#include <linux/proc_fs.h>
19#include <linux/slab.h>
20#include <linux/syscalls.h>
21#include <linux/utsname.h>
22#include <linux/socket.h>
23#include <linux/un.h>
24#include <linux/workqueue.h>
25#include <linux/mutex.h>
26#include <linux/fs.h>
27#include <linux/mount.h>
28#include <linux/file.h>
29#include <linux/uaccess.h>
30#include <asm/switch_to.h>
31
32#include <init.h>
33#include <irq_kern.h>
34#include <irq_user.h>
35#include <kern_util.h>
36#include "mconsole.h"
37#include "mconsole_kern.h"
38#include <os.h>
39
40static struct vfsmount *proc_mnt = NULL;
41
42static int do_unlink_socket(struct notifier_block *notifier,
43 unsigned long what, void *data)
44{
45 return mconsole_unlink_socket();
46}
47
48
49static struct notifier_block reboot_notifier = {
50 .notifier_call = do_unlink_socket,
51 .priority = 0,
52};
53
54/* Safe without explicit locking for now. Tasklets provide their own
55 * locking, and the interrupt handler is safe because it can't interrupt
56 * itself and it can only happen on CPU 0.
57 */
58
59static LIST_HEAD(mc_requests);
60
61static void mc_work_proc(struct work_struct *unused)
62{
63 struct mconsole_entry *req;
64 unsigned long flags;
65
66 while (!list_empty(&mc_requests)) {
67 local_irq_save(flags);
68 req = list_entry(mc_requests.next, struct mconsole_entry, list);
69 list_del(&req->list);
70 local_irq_restore(flags);
71 req->request.cmd->handler(&req->request);
72 kfree(req);
73 }
74}
75
76static DECLARE_WORK(mconsole_work, mc_work_proc);
77
78static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
79{
80 /* long to avoid size mismatch warnings from gcc */
81 long fd;
82 struct mconsole_entry *new;
83 static struct mc_request req; /* that's OK */
84
85 fd = (long) dev_id;
86 while (mconsole_get_request(fd, &req)) {
87 if (req.cmd->context == MCONSOLE_INTR)
88 (*req.cmd->handler)(&req);
89 else {
90 new = kmalloc(sizeof(*new), GFP_NOWAIT);
91 if (new == NULL)
92 mconsole_reply(&req, "Out of memory", 1, 0);
93 else {
94 new->request = req;
95 new->request.regs = get_irq_regs()->regs;
96 list_add(&new->list, &mc_requests);
97 }
98 }
99 }
100 if (!list_empty(&mc_requests))
101 schedule_work(&mconsole_work);
102 return IRQ_HANDLED;
103}
104
105void mconsole_version(struct mc_request *req)
106{
107 char version[256];
108
109 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
110 utsname()->nodename, utsname()->release, utsname()->version,
111 utsname()->machine);
112 mconsole_reply(req, version, 0, 0);
113}
114
115void mconsole_log(struct mc_request *req)
116{
117 int len;
118 char *ptr = req->request.data;
119
120 ptr += strlen("log ");
121
122 len = req->len - (ptr - req->request.data);
123 printk(KERN_WARNING "%.*s", len, ptr);
124 mconsole_reply(req, "", 0, 0);
125}
126
127void mconsole_proc(struct mc_request *req)
128{
129 struct vfsmount *mnt = proc_mnt;
130 char *buf;
131 int len;
132 struct file *file;
133 int first_chunk = 1;
134 char *ptr = req->request.data;
135 loff_t pos = 0;
136
137 ptr += strlen("proc");
138 ptr = skip_spaces(ptr);
139
140 if (!mnt) {
141 mconsole_reply(req, "Proc not available", 1, 0);
142 goto out;
143 }
144 file = file_open_root_mnt(mnt, ptr, O_RDONLY, 0);
145 if (IS_ERR(file)) {
146 mconsole_reply(req, "Failed to open file", 1, 0);
147 printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
148 goto out;
149 }
150
151 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
152 if (buf == NULL) {
153 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
154 goto out_fput;
155 }
156
157 do {
158 len = kernel_read(file, buf, PAGE_SIZE - 1, &pos);
159 if (len < 0) {
160 mconsole_reply(req, "Read of file failed", 1, 0);
161 goto out_free;
162 }
163 /* Begin the file content on his own line. */
164 if (first_chunk) {
165 mconsole_reply(req, "\n", 0, 1);
166 first_chunk = 0;
167 }
168 buf[len] = '\0';
169 mconsole_reply(req, buf, 0, (len > 0));
170 } while (len > 0);
171 out_free:
172 kfree(buf);
173 out_fput:
174 fput(file);
175 out: ;
176}
177
178#define UML_MCONSOLE_HELPTEXT \
179"Commands: \n\
180 version - Get kernel version \n\
181 help - Print this message \n\
182 halt - Halt UML \n\
183 reboot - Reboot UML \n\
184 config <dev>=<config> - Add a new device to UML; \n\
185 same syntax as command line \n\
186 config <dev> - Query the configuration of a device \n\
187 remove <dev> - Remove a device from UML \n\
188 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
189 cad - invoke the Ctrl-Alt-Del handler \n\
190 stop - pause the UML; it will do nothing until it receives a 'go' \n\
191 go - continue the UML after a 'stop' \n\
192 log <string> - make UML enter <string> into the kernel log\n\
193 proc <file> - returns the contents of the UML's /proc/<file>\n\
194 stack <pid> - returns the stack of the specified pid\n\
195"
196
197void mconsole_help(struct mc_request *req)
198{
199 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
200}
201
202void mconsole_halt(struct mc_request *req)
203{
204 mconsole_reply(req, "", 0, 0);
205 machine_halt();
206}
207
208void mconsole_reboot(struct mc_request *req)
209{
210 mconsole_reply(req, "", 0, 0);
211 machine_restart(NULL);
212}
213
214void mconsole_cad(struct mc_request *req)
215{
216 mconsole_reply(req, "", 0, 0);
217 ctrl_alt_del();
218}
219
220void mconsole_go(struct mc_request *req)
221{
222 mconsole_reply(req, "Not stopped", 1, 0);
223}
224
225void mconsole_stop(struct mc_request *req)
226{
227 block_signals();
228 os_set_fd_block(req->originating_fd, 1);
229 mconsole_reply(req, "stopped", 0, 0);
230 for (;;) {
231 if (!mconsole_get_request(req->originating_fd, req))
232 continue;
233 if (req->cmd->handler == mconsole_go)
234 break;
235 if (req->cmd->handler == mconsole_stop) {
236 mconsole_reply(req, "Already stopped", 1, 0);
237 continue;
238 }
239 if (req->cmd->handler == mconsole_sysrq) {
240 struct pt_regs *old_regs;
241 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
242 mconsole_sysrq(req);
243 set_irq_regs(old_regs);
244 continue;
245 }
246 (*req->cmd->handler)(req);
247 }
248 os_set_fd_block(req->originating_fd, 0);
249 mconsole_reply(req, "", 0, 0);
250 unblock_signals();
251}
252
253static DEFINE_SPINLOCK(mc_devices_lock);
254static LIST_HEAD(mconsole_devices);
255
256void mconsole_register_dev(struct mc_device *new)
257{
258 spin_lock(&mc_devices_lock);
259 BUG_ON(!list_empty(&new->list));
260 list_add(&new->list, &mconsole_devices);
261 spin_unlock(&mc_devices_lock);
262}
263
264static struct mc_device *mconsole_find_dev(char *name)
265{
266 struct list_head *ele;
267 struct mc_device *dev;
268
269 list_for_each(ele, &mconsole_devices) {
270 dev = list_entry(ele, struct mc_device, list);
271 if (!strncmp(name, dev->name, strlen(dev->name)))
272 return dev;
273 }
274 return NULL;
275}
276
277#define UNPLUGGED_PER_PAGE \
278 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
279
280struct unplugged_pages {
281 struct list_head list;
282 void *pages[UNPLUGGED_PER_PAGE];
283};
284
285static DEFINE_MUTEX(plug_mem_mutex);
286static unsigned long long unplugged_pages_count;
287static LIST_HEAD(unplugged_pages);
288static int unplug_index = UNPLUGGED_PER_PAGE;
289
290static int mem_config(char *str, char **error_out)
291{
292 unsigned long long diff;
293 int err = -EINVAL, i, add;
294 char *ret;
295
296 if (str[0] != '=') {
297 *error_out = "Expected '=' after 'mem'";
298 goto out;
299 }
300
301 str++;
302 if (str[0] == '-')
303 add = 0;
304 else if (str[0] == '+') {
305 add = 1;
306 }
307 else {
308 *error_out = "Expected increment to start with '-' or '+'";
309 goto out;
310 }
311
312 str++;
313 diff = memparse(str, &ret);
314 if (*ret != '\0') {
315 *error_out = "Failed to parse memory increment";
316 goto out;
317 }
318
319 diff /= PAGE_SIZE;
320
321 mutex_lock(&plug_mem_mutex);
322 for (i = 0; i < diff; i++) {
323 struct unplugged_pages *unplugged;
324 void *addr;
325
326 if (add) {
327 if (list_empty(&unplugged_pages))
328 break;
329
330 unplugged = list_entry(unplugged_pages.next,
331 struct unplugged_pages, list);
332 if (unplug_index > 0)
333 addr = unplugged->pages[--unplug_index];
334 else {
335 list_del(&unplugged->list);
336 addr = unplugged;
337 unplug_index = UNPLUGGED_PER_PAGE;
338 }
339
340 free_page((unsigned long) addr);
341 unplugged_pages_count--;
342 }
343 else {
344 struct page *page;
345
346 page = alloc_page(GFP_ATOMIC);
347 if (page == NULL)
348 break;
349
350 unplugged = page_address(page);
351 if (unplug_index == UNPLUGGED_PER_PAGE) {
352 list_add(&unplugged->list, &unplugged_pages);
353 unplug_index = 0;
354 }
355 else {
356 struct list_head *entry = unplugged_pages.next;
357 addr = unplugged;
358
359 unplugged = list_entry(entry,
360 struct unplugged_pages,
361 list);
362 err = os_drop_memory(addr, PAGE_SIZE);
363 if (err) {
364 printk(KERN_ERR "Failed to release "
365 "memory - errno = %d\n", err);
366 *error_out = "Failed to release memory";
367 goto out_unlock;
368 }
369 unplugged->pages[unplug_index++] = addr;
370 }
371
372 unplugged_pages_count++;
373 }
374 }
375
376 err = 0;
377out_unlock:
378 mutex_unlock(&plug_mem_mutex);
379out:
380 return err;
381}
382
383static int mem_get_config(char *name, char *str, int size, char **error_out)
384{
385 char buf[sizeof("18446744073709551615")];
386 int len = 0;
387
388 sprintf(buf, "%ld", uml_physmem);
389 CONFIG_CHUNK(str, size, len, buf, 1);
390
391 return len;
392}
393
394static int mem_id(char **str, int *start_out, int *end_out)
395{
396 *start_out = 0;
397 *end_out = 0;
398
399 return 0;
400}
401
402static int mem_remove(int n, char **error_out)
403{
404 *error_out = "Memory doesn't support the remove operation";
405 return -EBUSY;
406}
407
408static struct mc_device mem_mc = {
409 .list = LIST_HEAD_INIT(mem_mc.list),
410 .name = "mem",
411 .config = mem_config,
412 .get_config = mem_get_config,
413 .id = mem_id,
414 .remove = mem_remove,
415};
416
417static int __init mem_mc_init(void)
418{
419 if (can_drop_memory())
420 mconsole_register_dev(&mem_mc);
421 else printk(KERN_ERR "Can't release memory to the host - memory "
422 "hotplug won't be supported\n");
423 return 0;
424}
425
426__initcall(mem_mc_init);
427
428#define CONFIG_BUF_SIZE 64
429
430static void mconsole_get_config(int (*get_config)(char *, char *, int,
431 char **),
432 struct mc_request *req, char *name)
433{
434 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
435 int n, size;
436
437 if (get_config == NULL) {
438 mconsole_reply(req, "No get_config routine defined", 1, 0);
439 return;
440 }
441
442 error = NULL;
443 size = ARRAY_SIZE(default_buf);
444 buf = default_buf;
445
446 while (1) {
447 n = (*get_config)(name, buf, size, &error);
448 if (error != NULL) {
449 mconsole_reply(req, error, 1, 0);
450 goto out;
451 }
452
453 if (n <= size) {
454 mconsole_reply(req, buf, 0, 0);
455 goto out;
456 }
457
458 if (buf != default_buf)
459 kfree(buf);
460
461 size = n;
462 buf = kmalloc(size, GFP_KERNEL);
463 if (buf == NULL) {
464 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
465 return;
466 }
467 }
468 out:
469 if (buf != default_buf)
470 kfree(buf);
471}
472
473void mconsole_config(struct mc_request *req)
474{
475 struct mc_device *dev;
476 char *ptr = req->request.data, *name, *error_string = "";
477 int err;
478
479 ptr += strlen("config");
480 ptr = skip_spaces(ptr);
481 dev = mconsole_find_dev(ptr);
482 if (dev == NULL) {
483 mconsole_reply(req, "Bad configuration option", 1, 0);
484 return;
485 }
486
487 name = &ptr[strlen(dev->name)];
488 ptr = name;
489 while ((*ptr != '=') && (*ptr != '\0'))
490 ptr++;
491
492 if (*ptr == '=') {
493 err = (*dev->config)(name, &error_string);
494 mconsole_reply(req, error_string, err, 0);
495 }
496 else mconsole_get_config(dev->get_config, req, name);
497}
498
499void mconsole_remove(struct mc_request *req)
500{
501 struct mc_device *dev;
502 char *ptr = req->request.data, *err_msg = "";
503 char error[256];
504 int err, start, end, n;
505
506 ptr += strlen("remove");
507 ptr = skip_spaces(ptr);
508 dev = mconsole_find_dev(ptr);
509 if (dev == NULL) {
510 mconsole_reply(req, "Bad remove option", 1, 0);
511 return;
512 }
513
514 ptr = &ptr[strlen(dev->name)];
515
516 err = 1;
517 n = (*dev->id)(&ptr, &start, &end);
518 if (n < 0) {
519 err_msg = "Couldn't parse device number";
520 goto out;
521 }
522 else if ((n < start) || (n > end)) {
523 sprintf(error, "Invalid device number - must be between "
524 "%d and %d", start, end);
525 err_msg = error;
526 goto out;
527 }
528
529 err_msg = NULL;
530 err = (*dev->remove)(n, &err_msg);
531 switch(err) {
532 case 0:
533 err_msg = "";
534 break;
535 case -ENODEV:
536 if (err_msg == NULL)
537 err_msg = "Device doesn't exist";
538 break;
539 case -EBUSY:
540 if (err_msg == NULL)
541 err_msg = "Device is currently open";
542 break;
543 default:
544 break;
545 }
546out:
547 mconsole_reply(req, err_msg, err, 0);
548}
549
550struct mconsole_output {
551 struct list_head list;
552 struct mc_request *req;
553};
554
555static DEFINE_SPINLOCK(client_lock);
556static LIST_HEAD(clients);
557static char console_buf[MCONSOLE_MAX_DATA] __nonstring;
558
559static void console_write(struct console *console, const char *string,
560 unsigned int len)
561{
562 struct list_head *ele;
563 int n;
564
565 if (list_empty(&clients))
566 return;
567
568 while (len > 0) {
569 n = min((size_t) len, ARRAY_SIZE(console_buf));
570 memcpy(console_buf, string, n);
571 string += n;
572 len -= n;
573
574 list_for_each(ele, &clients) {
575 struct mconsole_output *entry;
576
577 entry = list_entry(ele, struct mconsole_output, list);
578 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
579 }
580 }
581}
582
583static struct console mc_console = { .name = "mc",
584 .write = console_write,
585 .flags = CON_ENABLED,
586 .index = -1 };
587
588static int mc_add_console(void)
589{
590 register_console(&mc_console);
591 return 0;
592}
593
594late_initcall(mc_add_console);
595
596static void with_console(struct mc_request *req, void (*proc)(void *),
597 void *arg)
598{
599 struct mconsole_output entry;
600 unsigned long flags;
601
602 entry.req = req;
603 spin_lock_irqsave(&client_lock, flags);
604 list_add(&entry.list, &clients);
605 spin_unlock_irqrestore(&client_lock, flags);
606
607 (*proc)(arg);
608
609 mconsole_reply_len(req, "", 0, 0, 0);
610
611 spin_lock_irqsave(&client_lock, flags);
612 list_del(&entry.list);
613 spin_unlock_irqrestore(&client_lock, flags);
614}
615
616#ifdef CONFIG_MAGIC_SYSRQ
617
618#include <linux/sysrq.h>
619
620static void sysrq_proc(void *arg)
621{
622 char *op = arg;
623 handle_sysrq(*op);
624}
625
626void mconsole_sysrq(struct mc_request *req)
627{
628 char *ptr = req->request.data;
629
630 ptr += strlen("sysrq");
631 ptr = skip_spaces(ptr);
632
633 /*
634 * With 'b', the system will shut down without a chance to reply,
635 * so in this case, we reply first.
636 */
637 if (*ptr == 'b')
638 mconsole_reply(req, "", 0, 0);
639
640 with_console(req, sysrq_proc, ptr);
641}
642#else
643void mconsole_sysrq(struct mc_request *req)
644{
645 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
646}
647#endif
648
649static void stack_proc(void *arg)
650{
651 struct task_struct *task = arg;
652
653 show_stack(task, NULL, KERN_INFO);
654}
655
656/*
657 * Mconsole stack trace
658 * Added by Allan Graves, Jeff Dike
659 * Dumps a stacks registers to the linux console.
660 * Usage stack <pid>.
661 */
662void mconsole_stack(struct mc_request *req)
663{
664 char *ptr = req->request.data;
665 int pid_requested= -1;
666 struct task_struct *to = NULL;
667
668 /*
669 * Would be nice:
670 * 1) Send showregs output to mconsole.
671 * 2) Add a way to stack dump all pids.
672 */
673
674 ptr += strlen("stack");
675 ptr = skip_spaces(ptr);
676
677 /*
678 * Should really check for multiple pids or reject bad args here
679 */
680 /* What do the arguments in mconsole_reply mean? */
681 if (sscanf(ptr, "%d", &pid_requested) == 0) {
682 mconsole_reply(req, "Please specify a pid", 1, 0);
683 return;
684 }
685
686 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
687 if ((to == NULL) || (pid_requested == 0)) {
688 mconsole_reply(req, "Couldn't find that pid", 1, 0);
689 return;
690 }
691 with_console(req, stack_proc, to);
692}
693
694static int __init mount_proc(void)
695{
696 struct file_system_type *proc_fs_type;
697 struct vfsmount *mnt;
698
699 proc_fs_type = get_fs_type("proc");
700 if (!proc_fs_type)
701 return -ENODEV;
702
703 mnt = kern_mount(proc_fs_type);
704 put_filesystem(proc_fs_type);
705 if (IS_ERR(mnt))
706 return PTR_ERR(mnt);
707
708 proc_mnt = mnt;
709 return 0;
710}
711
712/*
713 * Changed by mconsole_setup, which is __setup, and called before SMP is
714 * active.
715 */
716static char *notify_socket = NULL;
717
718static int __init mconsole_init(void)
719{
720 /* long to avoid size mismatch warnings from gcc */
721 long sock;
722 int err;
723 char file[UNIX_PATH_MAX];
724
725 mount_proc();
726
727 if (umid_file_name("mconsole", file, sizeof(file)))
728 return -1;
729 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
730
731 sock = os_create_unix_socket(file, sizeof(file), 1);
732 if (sock < 0) {
733 printk(KERN_ERR "Failed to initialize management console\n");
734 return 1;
735 }
736 if (os_set_fd_block(sock, 0))
737 goto out;
738
739 register_reboot_notifier(&reboot_notifier);
740
741 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
742 IRQF_SHARED, "mconsole", (void *)sock);
743 if (err < 0) {
744 printk(KERN_ERR "Failed to get IRQ for management console\n");
745 goto out;
746 }
747
748 if (notify_socket != NULL) {
749 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
750 if (notify_socket != NULL)
751 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
752 mconsole_socket_name,
753 strlen(mconsole_socket_name) + 1);
754 else printk(KERN_ERR "mconsole_setup failed to strdup "
755 "string\n");
756 }
757
758 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
759 MCONSOLE_VERSION, mconsole_socket_name);
760 return 0;
761
762 out:
763 os_close_file(sock);
764 return 1;
765}
766
767__initcall(mconsole_init);
768
769static ssize_t mconsole_proc_write(struct file *file,
770 const char __user *buffer, size_t count, loff_t *pos)
771{
772 char *buf;
773
774 buf = memdup_user_nul(buffer, count);
775 if (IS_ERR(buf))
776 return PTR_ERR(buf);
777
778 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
779 kfree(buf);
780 return count;
781}
782
783static const struct proc_ops mconsole_proc_ops = {
784 .proc_write = mconsole_proc_write,
785 .proc_lseek = noop_llseek,
786};
787
788static int create_proc_mconsole(void)
789{
790 struct proc_dir_entry *ent;
791
792 if (notify_socket == NULL)
793 return 0;
794
795 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_ops);
796 if (ent == NULL) {
797 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
798 return 0;
799 }
800 return 0;
801}
802
803static DEFINE_SPINLOCK(notify_spinlock);
804
805void lock_notify(void)
806{
807 spin_lock(¬ify_spinlock);
808}
809
810void unlock_notify(void)
811{
812 spin_unlock(¬ify_spinlock);
813}
814
815__initcall(create_proc_mconsole);
816
817#define NOTIFY "notify:"
818
819static int mconsole_setup(char *str)
820{
821 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
822 str += strlen(NOTIFY);
823 notify_socket = str;
824 }
825 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
826 return 1;
827}
828
829__setup("mconsole=", mconsole_setup);
830
831__uml_help(mconsole_setup,
832"mconsole=notify:<socket>\n"
833" Requests that the mconsole driver send a message to the named Unix\n"
834" socket containing the name of the mconsole socket. This also serves\n"
835" to notify outside processes when UML has booted far enough to respond\n"
836" to mconsole requests.\n\n"
837);
838
839static int notify_panic(struct notifier_block *self, unsigned long unused1,
840 void *ptr)
841{
842 char *message = ptr;
843
844 if (notify_socket == NULL)
845 return 0;
846
847 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
848 strlen(message) + 1);
849 return NOTIFY_DONE;
850}
851
852static struct notifier_block panic_exit_notifier = {
853 .notifier_call = notify_panic,
854 .priority = INT_MAX, /* run as soon as possible */
855};
856
857static int add_notifier(void)
858{
859 atomic_notifier_chain_register(&panic_notifier_list,
860 &panic_exit_notifier);
861 return 0;
862}
863
864__initcall(add_notifier);
865
866char *mconsole_notify_socket(void)
867{
868 return notify_socket;
869}
870
871EXPORT_SYMBOL(mconsole_notify_socket);
1/*
2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3 * Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
5 */
6
7#include <linux/console.h>
8#include <linux/ctype.h>
9#include <linux/string.h>
10#include <linux/interrupt.h>
11#include <linux/list.h>
12#include <linux/mm.h>
13#include <linux/module.h>
14#include <linux/notifier.h>
15#include <linux/reboot.h>
16#include <linux/proc_fs.h>
17#include <linux/slab.h>
18#include <linux/syscalls.h>
19#include <linux/utsname.h>
20#include <linux/socket.h>
21#include <linux/un.h>
22#include <linux/workqueue.h>
23#include <linux/mutex.h>
24#include <linux/fs.h>
25#include <linux/mount.h>
26#include <linux/file.h>
27#include <asm/uaccess.h>
28#include <asm/switch_to.h>
29
30#include <init.h>
31#include <irq_kern.h>
32#include <irq_user.h>
33#include <kern_util.h>
34#include "mconsole.h"
35#include "mconsole_kern.h"
36#include <os.h>
37
38static int do_unlink_socket(struct notifier_block *notifier,
39 unsigned long what, void *data)
40{
41 return mconsole_unlink_socket();
42}
43
44
45static struct notifier_block reboot_notifier = {
46 .notifier_call = do_unlink_socket,
47 .priority = 0,
48};
49
50/* Safe without explicit locking for now. Tasklets provide their own
51 * locking, and the interrupt handler is safe because it can't interrupt
52 * itself and it can only happen on CPU 0.
53 */
54
55static LIST_HEAD(mc_requests);
56
57static void mc_work_proc(struct work_struct *unused)
58{
59 struct mconsole_entry *req;
60 unsigned long flags;
61
62 while (!list_empty(&mc_requests)) {
63 local_irq_save(flags);
64 req = list_entry(mc_requests.next, struct mconsole_entry, list);
65 list_del(&req->list);
66 local_irq_restore(flags);
67 req->request.cmd->handler(&req->request);
68 kfree(req);
69 }
70}
71
72static DECLARE_WORK(mconsole_work, mc_work_proc);
73
74static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
75{
76 /* long to avoid size mismatch warnings from gcc */
77 long fd;
78 struct mconsole_entry *new;
79 static struct mc_request req; /* that's OK */
80
81 fd = (long) dev_id;
82 while (mconsole_get_request(fd, &req)) {
83 if (req.cmd->context == MCONSOLE_INTR)
84 (*req.cmd->handler)(&req);
85 else {
86 new = kmalloc(sizeof(*new), GFP_NOWAIT);
87 if (new == NULL)
88 mconsole_reply(&req, "Out of memory", 1, 0);
89 else {
90 new->request = req;
91 new->request.regs = get_irq_regs()->regs;
92 list_add(&new->list, &mc_requests);
93 }
94 }
95 }
96 if (!list_empty(&mc_requests))
97 schedule_work(&mconsole_work);
98 reactivate_fd(fd, MCONSOLE_IRQ);
99 return IRQ_HANDLED;
100}
101
102void mconsole_version(struct mc_request *req)
103{
104 char version[256];
105
106 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
107 utsname()->nodename, utsname()->release, utsname()->version,
108 utsname()->machine);
109 mconsole_reply(req, version, 0, 0);
110}
111
112void mconsole_log(struct mc_request *req)
113{
114 int len;
115 char *ptr = req->request.data;
116
117 ptr += strlen("log ");
118
119 len = req->len - (ptr - req->request.data);
120 printk(KERN_WARNING "%.*s", len, ptr);
121 mconsole_reply(req, "", 0, 0);
122}
123
124void mconsole_proc(struct mc_request *req)
125{
126 struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
127 char *buf;
128 int len;
129 struct file *file;
130 int first_chunk = 1;
131 char *ptr = req->request.data;
132
133 ptr += strlen("proc");
134 ptr = skip_spaces(ptr);
135
136 file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0);
137 if (IS_ERR(file)) {
138 mconsole_reply(req, "Failed to open file", 1, 0);
139 printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
140 goto out;
141 }
142
143 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
144 if (buf == NULL) {
145 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
146 goto out_fput;
147 }
148
149 do {
150 loff_t pos = file->f_pos;
151 mm_segment_t old_fs = get_fs();
152 set_fs(KERNEL_DS);
153 len = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
154 set_fs(old_fs);
155 file->f_pos = pos;
156 if (len < 0) {
157 mconsole_reply(req, "Read of file failed", 1, 0);
158 goto out_free;
159 }
160 /* Begin the file content on his own line. */
161 if (first_chunk) {
162 mconsole_reply(req, "\n", 0, 1);
163 first_chunk = 0;
164 }
165 buf[len] = '\0';
166 mconsole_reply(req, buf, 0, (len > 0));
167 } while (len > 0);
168 out_free:
169 kfree(buf);
170 out_fput:
171 fput(file);
172 out: ;
173}
174
175#define UML_MCONSOLE_HELPTEXT \
176"Commands: \n\
177 version - Get kernel version \n\
178 help - Print this message \n\
179 halt - Halt UML \n\
180 reboot - Reboot UML \n\
181 config <dev>=<config> - Add a new device to UML; \n\
182 same syntax as command line \n\
183 config <dev> - Query the configuration of a device \n\
184 remove <dev> - Remove a device from UML \n\
185 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
186 cad - invoke the Ctrl-Alt-Del handler \n\
187 stop - pause the UML; it will do nothing until it receives a 'go' \n\
188 go - continue the UML after a 'stop' \n\
189 log <string> - make UML enter <string> into the kernel log\n\
190 proc <file> - returns the contents of the UML's /proc/<file>\n\
191 stack <pid> - returns the stack of the specified pid\n\
192"
193
194void mconsole_help(struct mc_request *req)
195{
196 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
197}
198
199void mconsole_halt(struct mc_request *req)
200{
201 mconsole_reply(req, "", 0, 0);
202 machine_halt();
203}
204
205void mconsole_reboot(struct mc_request *req)
206{
207 mconsole_reply(req, "", 0, 0);
208 machine_restart(NULL);
209}
210
211void mconsole_cad(struct mc_request *req)
212{
213 mconsole_reply(req, "", 0, 0);
214 ctrl_alt_del();
215}
216
217void mconsole_go(struct mc_request *req)
218{
219 mconsole_reply(req, "Not stopped", 1, 0);
220}
221
222void mconsole_stop(struct mc_request *req)
223{
224 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
225 os_set_fd_block(req->originating_fd, 1);
226 mconsole_reply(req, "stopped", 0, 0);
227 for (;;) {
228 if (!mconsole_get_request(req->originating_fd, req))
229 continue;
230 if (req->cmd->handler == mconsole_go)
231 break;
232 if (req->cmd->handler == mconsole_stop) {
233 mconsole_reply(req, "Already stopped", 1, 0);
234 continue;
235 }
236 if (req->cmd->handler == mconsole_sysrq) {
237 struct pt_regs *old_regs;
238 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
239 mconsole_sysrq(req);
240 set_irq_regs(old_regs);
241 continue;
242 }
243 (*req->cmd->handler)(req);
244 }
245 os_set_fd_block(req->originating_fd, 0);
246 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
247 mconsole_reply(req, "", 0, 0);
248}
249
250static DEFINE_SPINLOCK(mc_devices_lock);
251static LIST_HEAD(mconsole_devices);
252
253void mconsole_register_dev(struct mc_device *new)
254{
255 spin_lock(&mc_devices_lock);
256 BUG_ON(!list_empty(&new->list));
257 list_add(&new->list, &mconsole_devices);
258 spin_unlock(&mc_devices_lock);
259}
260
261static struct mc_device *mconsole_find_dev(char *name)
262{
263 struct list_head *ele;
264 struct mc_device *dev;
265
266 list_for_each(ele, &mconsole_devices) {
267 dev = list_entry(ele, struct mc_device, list);
268 if (!strncmp(name, dev->name, strlen(dev->name)))
269 return dev;
270 }
271 return NULL;
272}
273
274#define UNPLUGGED_PER_PAGE \
275 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
276
277struct unplugged_pages {
278 struct list_head list;
279 void *pages[UNPLUGGED_PER_PAGE];
280};
281
282static DEFINE_MUTEX(plug_mem_mutex);
283static unsigned long long unplugged_pages_count = 0;
284static LIST_HEAD(unplugged_pages);
285static int unplug_index = UNPLUGGED_PER_PAGE;
286
287static int mem_config(char *str, char **error_out)
288{
289 unsigned long long diff;
290 int err = -EINVAL, i, add;
291 char *ret;
292
293 if (str[0] != '=') {
294 *error_out = "Expected '=' after 'mem'";
295 goto out;
296 }
297
298 str++;
299 if (str[0] == '-')
300 add = 0;
301 else if (str[0] == '+') {
302 add = 1;
303 }
304 else {
305 *error_out = "Expected increment to start with '-' or '+'";
306 goto out;
307 }
308
309 str++;
310 diff = memparse(str, &ret);
311 if (*ret != '\0') {
312 *error_out = "Failed to parse memory increment";
313 goto out;
314 }
315
316 diff /= PAGE_SIZE;
317
318 mutex_lock(&plug_mem_mutex);
319 for (i = 0; i < diff; i++) {
320 struct unplugged_pages *unplugged;
321 void *addr;
322
323 if (add) {
324 if (list_empty(&unplugged_pages))
325 break;
326
327 unplugged = list_entry(unplugged_pages.next,
328 struct unplugged_pages, list);
329 if (unplug_index > 0)
330 addr = unplugged->pages[--unplug_index];
331 else {
332 list_del(&unplugged->list);
333 addr = unplugged;
334 unplug_index = UNPLUGGED_PER_PAGE;
335 }
336
337 free_page((unsigned long) addr);
338 unplugged_pages_count--;
339 }
340 else {
341 struct page *page;
342
343 page = alloc_page(GFP_ATOMIC);
344 if (page == NULL)
345 break;
346
347 unplugged = page_address(page);
348 if (unplug_index == UNPLUGGED_PER_PAGE) {
349 list_add(&unplugged->list, &unplugged_pages);
350 unplug_index = 0;
351 }
352 else {
353 struct list_head *entry = unplugged_pages.next;
354 addr = unplugged;
355
356 unplugged = list_entry(entry,
357 struct unplugged_pages,
358 list);
359 err = os_drop_memory(addr, PAGE_SIZE);
360 if (err) {
361 printk(KERN_ERR "Failed to release "
362 "memory - errno = %d\n", err);
363 *error_out = "Failed to release memory";
364 goto out_unlock;
365 }
366 unplugged->pages[unplug_index++] = addr;
367 }
368
369 unplugged_pages_count++;
370 }
371 }
372
373 err = 0;
374out_unlock:
375 mutex_unlock(&plug_mem_mutex);
376out:
377 return err;
378}
379
380static int mem_get_config(char *name, char *str, int size, char **error_out)
381{
382 char buf[sizeof("18446744073709551615")];
383 int len = 0;
384
385 sprintf(buf, "%ld", uml_physmem);
386 CONFIG_CHUNK(str, size, len, buf, 1);
387
388 return len;
389}
390
391static int mem_id(char **str, int *start_out, int *end_out)
392{
393 *start_out = 0;
394 *end_out = 0;
395
396 return 0;
397}
398
399static int mem_remove(int n, char **error_out)
400{
401 *error_out = "Memory doesn't support the remove operation";
402 return -EBUSY;
403}
404
405static struct mc_device mem_mc = {
406 .list = LIST_HEAD_INIT(mem_mc.list),
407 .name = "mem",
408 .config = mem_config,
409 .get_config = mem_get_config,
410 .id = mem_id,
411 .remove = mem_remove,
412};
413
414static int __init mem_mc_init(void)
415{
416 if (can_drop_memory())
417 mconsole_register_dev(&mem_mc);
418 else printk(KERN_ERR "Can't release memory to the host - memory "
419 "hotplug won't be supported\n");
420 return 0;
421}
422
423__initcall(mem_mc_init);
424
425#define CONFIG_BUF_SIZE 64
426
427static void mconsole_get_config(int (*get_config)(char *, char *, int,
428 char **),
429 struct mc_request *req, char *name)
430{
431 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
432 int n, size;
433
434 if (get_config == NULL) {
435 mconsole_reply(req, "No get_config routine defined", 1, 0);
436 return;
437 }
438
439 error = NULL;
440 size = ARRAY_SIZE(default_buf);
441 buf = default_buf;
442
443 while (1) {
444 n = (*get_config)(name, buf, size, &error);
445 if (error != NULL) {
446 mconsole_reply(req, error, 1, 0);
447 goto out;
448 }
449
450 if (n <= size) {
451 mconsole_reply(req, buf, 0, 0);
452 goto out;
453 }
454
455 if (buf != default_buf)
456 kfree(buf);
457
458 size = n;
459 buf = kmalloc(size, GFP_KERNEL);
460 if (buf == NULL) {
461 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
462 return;
463 }
464 }
465 out:
466 if (buf != default_buf)
467 kfree(buf);
468}
469
470void mconsole_config(struct mc_request *req)
471{
472 struct mc_device *dev;
473 char *ptr = req->request.data, *name, *error_string = "";
474 int err;
475
476 ptr += strlen("config");
477 ptr = skip_spaces(ptr);
478 dev = mconsole_find_dev(ptr);
479 if (dev == NULL) {
480 mconsole_reply(req, "Bad configuration option", 1, 0);
481 return;
482 }
483
484 name = &ptr[strlen(dev->name)];
485 ptr = name;
486 while ((*ptr != '=') && (*ptr != '\0'))
487 ptr++;
488
489 if (*ptr == '=') {
490 err = (*dev->config)(name, &error_string);
491 mconsole_reply(req, error_string, err, 0);
492 }
493 else mconsole_get_config(dev->get_config, req, name);
494}
495
496void mconsole_remove(struct mc_request *req)
497{
498 struct mc_device *dev;
499 char *ptr = req->request.data, *err_msg = "";
500 char error[256];
501 int err, start, end, n;
502
503 ptr += strlen("remove");
504 ptr = skip_spaces(ptr);
505 dev = mconsole_find_dev(ptr);
506 if (dev == NULL) {
507 mconsole_reply(req, "Bad remove option", 1, 0);
508 return;
509 }
510
511 ptr = &ptr[strlen(dev->name)];
512
513 err = 1;
514 n = (*dev->id)(&ptr, &start, &end);
515 if (n < 0) {
516 err_msg = "Couldn't parse device number";
517 goto out;
518 }
519 else if ((n < start) || (n > end)) {
520 sprintf(error, "Invalid device number - must be between "
521 "%d and %d", start, end);
522 err_msg = error;
523 goto out;
524 }
525
526 err_msg = NULL;
527 err = (*dev->remove)(n, &err_msg);
528 switch(err) {
529 case 0:
530 err_msg = "";
531 break;
532 case -ENODEV:
533 if (err_msg == NULL)
534 err_msg = "Device doesn't exist";
535 break;
536 case -EBUSY:
537 if (err_msg == NULL)
538 err_msg = "Device is currently open";
539 break;
540 default:
541 break;
542 }
543out:
544 mconsole_reply(req, err_msg, err, 0);
545}
546
547struct mconsole_output {
548 struct list_head list;
549 struct mc_request *req;
550};
551
552static DEFINE_SPINLOCK(client_lock);
553static LIST_HEAD(clients);
554static char console_buf[MCONSOLE_MAX_DATA];
555
556static void console_write(struct console *console, const char *string,
557 unsigned int len)
558{
559 struct list_head *ele;
560 int n;
561
562 if (list_empty(&clients))
563 return;
564
565 while (len > 0) {
566 n = min((size_t) len, ARRAY_SIZE(console_buf));
567 strncpy(console_buf, string, n);
568 string += n;
569 len -= n;
570
571 list_for_each(ele, &clients) {
572 struct mconsole_output *entry;
573
574 entry = list_entry(ele, struct mconsole_output, list);
575 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
576 }
577 }
578}
579
580static struct console mc_console = { .name = "mc",
581 .write = console_write,
582 .flags = CON_ENABLED,
583 .index = -1 };
584
585static int mc_add_console(void)
586{
587 register_console(&mc_console);
588 return 0;
589}
590
591late_initcall(mc_add_console);
592
593static void with_console(struct mc_request *req, void (*proc)(void *),
594 void *arg)
595{
596 struct mconsole_output entry;
597 unsigned long flags;
598
599 entry.req = req;
600 spin_lock_irqsave(&client_lock, flags);
601 list_add(&entry.list, &clients);
602 spin_unlock_irqrestore(&client_lock, flags);
603
604 (*proc)(arg);
605
606 mconsole_reply_len(req, "", 0, 0, 0);
607
608 spin_lock_irqsave(&client_lock, flags);
609 list_del(&entry.list);
610 spin_unlock_irqrestore(&client_lock, flags);
611}
612
613#ifdef CONFIG_MAGIC_SYSRQ
614
615#include <linux/sysrq.h>
616
617static void sysrq_proc(void *arg)
618{
619 char *op = arg;
620 handle_sysrq(*op);
621}
622
623void mconsole_sysrq(struct mc_request *req)
624{
625 char *ptr = req->request.data;
626
627 ptr += strlen("sysrq");
628 ptr = skip_spaces(ptr);
629
630 /*
631 * With 'b', the system will shut down without a chance to reply,
632 * so in this case, we reply first.
633 */
634 if (*ptr == 'b')
635 mconsole_reply(req, "", 0, 0);
636
637 with_console(req, sysrq_proc, ptr);
638}
639#else
640void mconsole_sysrq(struct mc_request *req)
641{
642 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
643}
644#endif
645
646static void stack_proc(void *arg)
647{
648 struct task_struct *task = arg;
649
650 show_stack(task, NULL);
651}
652
653/*
654 * Mconsole stack trace
655 * Added by Allan Graves, Jeff Dike
656 * Dumps a stacks registers to the linux console.
657 * Usage stack <pid>.
658 */
659void mconsole_stack(struct mc_request *req)
660{
661 char *ptr = req->request.data;
662 int pid_requested= -1;
663 struct task_struct *to = NULL;
664
665 /*
666 * Would be nice:
667 * 1) Send showregs output to mconsole.
668 * 2) Add a way to stack dump all pids.
669 */
670
671 ptr += strlen("stack");
672 ptr = skip_spaces(ptr);
673
674 /*
675 * Should really check for multiple pids or reject bad args here
676 */
677 /* What do the arguments in mconsole_reply mean? */
678 if (sscanf(ptr, "%d", &pid_requested) == 0) {
679 mconsole_reply(req, "Please specify a pid", 1, 0);
680 return;
681 }
682
683 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
684 if ((to == NULL) || (pid_requested == 0)) {
685 mconsole_reply(req, "Couldn't find that pid", 1, 0);
686 return;
687 }
688 with_console(req, stack_proc, to);
689}
690
691/*
692 * Changed by mconsole_setup, which is __setup, and called before SMP is
693 * active.
694 */
695static char *notify_socket = NULL;
696
697static int __init mconsole_init(void)
698{
699 /* long to avoid size mismatch warnings from gcc */
700 long sock;
701 int err;
702 char file[UNIX_PATH_MAX];
703
704 if (umid_file_name("mconsole", file, sizeof(file)))
705 return -1;
706 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
707
708 sock = os_create_unix_socket(file, sizeof(file), 1);
709 if (sock < 0) {
710 printk(KERN_ERR "Failed to initialize management console\n");
711 return 1;
712 }
713 if (os_set_fd_block(sock, 0))
714 goto out;
715
716 register_reboot_notifier(&reboot_notifier);
717
718 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
719 IRQF_SHARED, "mconsole", (void *)sock);
720 if (err) {
721 printk(KERN_ERR "Failed to get IRQ for management console\n");
722 goto out;
723 }
724
725 if (notify_socket != NULL) {
726 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
727 if (notify_socket != NULL)
728 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
729 mconsole_socket_name,
730 strlen(mconsole_socket_name) + 1);
731 else printk(KERN_ERR "mconsole_setup failed to strdup "
732 "string\n");
733 }
734
735 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
736 MCONSOLE_VERSION, mconsole_socket_name);
737 return 0;
738
739 out:
740 os_close_file(sock);
741 return 1;
742}
743
744__initcall(mconsole_init);
745
746static ssize_t mconsole_proc_write(struct file *file,
747 const char __user *buffer, size_t count, loff_t *pos)
748{
749 char *buf;
750
751 buf = memdup_user_nul(buffer, count);
752 if (IS_ERR(buf))
753 return PTR_ERR(buf);
754
755 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
756 kfree(buf);
757 return count;
758}
759
760static const struct file_operations mconsole_proc_fops = {
761 .owner = THIS_MODULE,
762 .write = mconsole_proc_write,
763 .llseek = noop_llseek,
764};
765
766static int create_proc_mconsole(void)
767{
768 struct proc_dir_entry *ent;
769
770 if (notify_socket == NULL)
771 return 0;
772
773 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
774 if (ent == NULL) {
775 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
776 return 0;
777 }
778 return 0;
779}
780
781static DEFINE_SPINLOCK(notify_spinlock);
782
783void lock_notify(void)
784{
785 spin_lock(¬ify_spinlock);
786}
787
788void unlock_notify(void)
789{
790 spin_unlock(¬ify_spinlock);
791}
792
793__initcall(create_proc_mconsole);
794
795#define NOTIFY "notify:"
796
797static int mconsole_setup(char *str)
798{
799 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
800 str += strlen(NOTIFY);
801 notify_socket = str;
802 }
803 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
804 return 1;
805}
806
807__setup("mconsole=", mconsole_setup);
808
809__uml_help(mconsole_setup,
810"mconsole=notify:<socket>\n"
811" Requests that the mconsole driver send a message to the named Unix\n"
812" socket containing the name of the mconsole socket. This also serves\n"
813" to notify outside processes when UML has booted far enough to respond\n"
814" to mconsole requests.\n\n"
815);
816
817static int notify_panic(struct notifier_block *self, unsigned long unused1,
818 void *ptr)
819{
820 char *message = ptr;
821
822 if (notify_socket == NULL)
823 return 0;
824
825 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
826 strlen(message) + 1);
827 return 0;
828}
829
830static struct notifier_block panic_exit_notifier = {
831 .notifier_call = notify_panic,
832 .next = NULL,
833 .priority = 1
834};
835
836static int add_notifier(void)
837{
838 atomic_notifier_chain_register(&panic_notifier_list,
839 &panic_exit_notifier);
840 return 0;
841}
842
843__initcall(add_notifier);
844
845char *mconsole_notify_socket(void)
846{
847 return notify_socket;
848}
849
850EXPORT_SYMBOL(mconsole_notify_socket);