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
40 static struct vfsmount *proc_mnt = NULL;
41
42 static int do_unlink_socket(struct notifier_block *notifier,
43 unsigned long what, void *data)
44 {
45 return mconsole_unlink_socket();
46 }
47
48
49 static 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
59 static LIST_HEAD(mc_requests);
60
61 static 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
76 static DECLARE_WORK(mconsole_work, mc_work_proc);
77
78 static 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
105 void 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
115 void 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
127 void 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
197 void mconsole_help(struct mc_request *req)
198 {
199 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
200 }
201
202 void mconsole_halt(struct mc_request *req)
203 {
204 mconsole_reply(req, "", 0, 0);
205 machine_halt();
206 }
207
208 void mconsole_reboot(struct mc_request *req)
209 {
210 mconsole_reply(req, "", 0, 0);
211 machine_restart(NULL);
212 }
213
214 void mconsole_cad(struct mc_request *req)
215 {
216 mconsole_reply(req, "", 0, 0);
217 ctrl_alt_del();
218 }
219
220 void mconsole_go(struct mc_request *req)
221 {
222 mconsole_reply(req, "Not stopped", 1, 0);
223 }
224
225 void 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
253 static DEFINE_SPINLOCK(mc_devices_lock);
254 static LIST_HEAD(mconsole_devices);
255
256 void 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
264 static 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
280 struct unplugged_pages {
281 struct list_head list;
282 void *pages[UNPLUGGED_PER_PAGE];
283 };
284
285 static DEFINE_MUTEX(plug_mem_mutex);
286 static unsigned long long unplugged_pages_count;
287 static LIST_HEAD(unplugged_pages);
288 static int unplug_index = UNPLUGGED_PER_PAGE;
289
290 static 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;
377 out_unlock:
378 mutex_unlock(&plug_mem_mutex);
379 out:
380 return err;
381 }
382
383 static 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
394 static 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
402 static int mem_remove(int n, char **error_out)
403 {
404 *error_out = "Memory doesn't support the remove operation";
405 return -EBUSY;
406 }
407
408 static 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
417 static 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
430 static 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
473 void 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
499 void 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 }
546 out:
547 mconsole_reply(req, err_msg, err, 0);
548 }
549
550 struct mconsole_output {
551 struct list_head list;
552 struct mc_request *req;
553 };
554
555 static DEFINE_SPINLOCK(client_lock);
556 static LIST_HEAD(clients);
557 static char console_buf[MCONSOLE_MAX_DATA] __nonstring;
558
559 static 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
583 static struct console mc_console = { .name = "mc",
584 .write = console_write,
585 .flags = CON_ENABLED,
586 .index = -1 };
587
588 static int mc_add_console(void)
589 {
590 register_console(&mc_console);
591 return 0;
592 }
593
594 late_initcall(mc_add_console);
595
596 static 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
620 static void sysrq_proc(void *arg)
621 {
622 char *op = arg;
623 handle_sysrq(*op);
624 }
625
626 void 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
643 void mconsole_sysrq(struct mc_request *req)
644 {
645 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
646 }
647 #endif
648
649 static 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 */
662 void 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
694 static 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 */
716 static char *notify_socket = NULL;
717
718 static 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
769 static 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
783 static const struct proc_ops mconsole_proc_ops = {
784 .proc_write = mconsole_proc_write,
785 .proc_lseek = noop_llseek,
786 };
787
788 static 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
803 static DEFINE_SPINLOCK(notify_spinlock);
804
805 void lock_notify(void)
806 {
807 spin_lock(¬ify_spinlock);
808 }
809
810 void unlock_notify(void)
811 {
812 spin_unlock(¬ify_spinlock);
813 }
814
815 __initcall(create_proc_mconsole);
816
817 #define NOTIFY "notify:"
818
819 static 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
839 static 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
852 static struct notifier_block panic_exit_notifier = {
853 .notifier_call = notify_panic,
854 .priority = INT_MAX, /* run as soon as possible */
855 };
856
857 static 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
866 char *mconsole_notify_socket(void)
867 {
868 return notify_socket;
869 }
870
871 EXPORT_SYMBOL(mconsole_notify_socket);
872
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