xref: /linux/arch/um/drivers/mconsole_kern.c (revision 47902f3611b392209e2a412bf7ec02dca95e666d)
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 <asm/uaccess.h>
25 
26 #include "init.h"
27 #include "irq_kern.h"
28 #include "irq_user.h"
29 #include "kern_util.h"
30 #include "mconsole.h"
31 #include "mconsole_kern.h"
32 #include "os.h"
33 
34 static int do_unlink_socket(struct notifier_block *notifier,
35 			    unsigned long what, void *data)
36 {
37 	return mconsole_unlink_socket();
38 }
39 
40 
41 static struct notifier_block reboot_notifier = {
42 	.notifier_call		= do_unlink_socket,
43 	.priority		= 0,
44 };
45 
46 /* Safe without explicit locking for now.  Tasklets provide their own
47  * locking, and the interrupt handler is safe because it can't interrupt
48  * itself and it can only happen on CPU 0.
49  */
50 
51 static LIST_HEAD(mc_requests);
52 
53 static void mc_work_proc(struct work_struct *unused)
54 {
55 	struct mconsole_entry *req;
56 	unsigned long flags;
57 
58 	while (!list_empty(&mc_requests)) {
59 		local_irq_save(flags);
60 		req = list_entry(mc_requests.next, struct mconsole_entry, list);
61 		list_del(&req->list);
62 		local_irq_restore(flags);
63 		req->request.cmd->handler(&req->request);
64 		kfree(req);
65 	}
66 }
67 
68 static DECLARE_WORK(mconsole_work, mc_work_proc);
69 
70 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
71 {
72 	/* long to avoid size mismatch warnings from gcc */
73 	long fd;
74 	struct mconsole_entry *new;
75 	static struct mc_request req;	/* that's OK */
76 
77 	fd = (long) dev_id;
78 	while (mconsole_get_request(fd, &req)) {
79 		if (req.cmd->context == MCONSOLE_INTR)
80 			(*req.cmd->handler)(&req);
81 		else {
82 			new = kmalloc(sizeof(*new), GFP_NOWAIT);
83 			if (new == NULL)
84 				mconsole_reply(&req, "Out of memory", 1, 0);
85 			else {
86 				new->request = req;
87 				new->request.regs = get_irq_regs()->regs;
88 				list_add(&new->list, &mc_requests);
89 			}
90 		}
91 	}
92 	if (!list_empty(&mc_requests))
93 		schedule_work(&mconsole_work);
94 	reactivate_fd(fd, MCONSOLE_IRQ);
95 	return IRQ_HANDLED;
96 }
97 
98 void mconsole_version(struct mc_request *req)
99 {
100 	char version[256];
101 
102 	sprintf(version, "%s %s %s %s %s", utsname()->sysname,
103 		utsname()->nodename, utsname()->release, utsname()->version,
104 		utsname()->machine);
105 	mconsole_reply(req, version, 0, 0);
106 }
107 
108 void mconsole_log(struct mc_request *req)
109 {
110 	int len;
111 	char *ptr = req->request.data;
112 
113 	ptr += strlen("log ");
114 
115 	len = req->len - (ptr - req->request.data);
116 	printk(KERN_WARNING "%.*s", len, ptr);
117 	mconsole_reply(req, "", 0, 0);
118 }
119 
120 /* This is a more convoluted version of mconsole_proc, which has some stability
121  * problems; however, we need it fixed, because it is expected that UML users
122  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
123  * show the real procfs content, not the ones from hppfs.*/
124 #if 0
125 void mconsole_proc(struct mc_request *req)
126 {
127 	struct nameidata nd;
128 	struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;
129 	struct file *file;
130 	int n, err;
131 	char *ptr = req->request.data, *buf;
132 	mm_segment_t old_fs = get_fs();
133 
134 	ptr += strlen("proc");
135 	ptr = skip_spaces(ptr);
136 
137 	err = vfs_path_lookup(mnt->mnt_root, mnt, ptr, LOOKUP_FOLLOW, &nd);
138 	if (err) {
139 		mconsole_reply(req, "Failed to look up file", 1, 0);
140 		goto out;
141 	}
142 
143 	err = may_open(&nd.path, MAY_READ, O_RDONLY);
144 	if (result) {
145 		mconsole_reply(req, "Failed to open file", 1, 0);
146 		path_put(&nd.path);
147 		goto out;
148 	}
149 
150 	file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
151 			   current_cred());
152 	err = PTR_ERR(file);
153 	if (IS_ERR(file)) {
154 		mconsole_reply(req, "Failed to open file", 1, 0);
155 		path_put(&nd.path);
156 		goto out;
157 	}
158 
159 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
160 	if (buf == NULL) {
161 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
162 		goto out_fput;
163 	}
164 
165 	if (file->f_op->read) {
166 		do {
167 			loff_t pos;
168 			set_fs(KERNEL_DS);
169 			n = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
170 			file_pos_write(file, pos);
171 			set_fs(old_fs);
172 			if (n >= 0) {
173 				buf[n] = '\0';
174 				mconsole_reply(req, buf, 0, (n > 0));
175 			}
176 			else {
177 				mconsole_reply(req, "Read of file failed",
178 					       1, 0);
179 				goto out_free;
180 			}
181 		} while (n > 0);
182 	}
183 	else mconsole_reply(req, "", 0, 0);
184 
185  out_free:
186 	kfree(buf);
187  out_fput:
188 	fput(file);
189  out: ;
190 }
191 #endif
192 
193 void mconsole_proc(struct mc_request *req)
194 {
195 	char path[64];
196 	char *buf;
197 	int len;
198 	int fd;
199 	int first_chunk = 1;
200 	char *ptr = req->request.data;
201 
202 	ptr += strlen("proc");
203 	ptr = skip_spaces(ptr);
204 	snprintf(path, sizeof(path), "/proc/%s", ptr);
205 
206 	fd = sys_open(path, 0, 0);
207 	if (fd < 0) {
208 		mconsole_reply(req, "Failed to open file", 1, 0);
209 		printk(KERN_ERR "open %s: %d\n",path,fd);
210 		goto out;
211 	}
212 
213 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
214 	if (buf == NULL) {
215 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
216 		goto out_close;
217 	}
218 
219 	for (;;) {
220 		len = sys_read(fd, buf, PAGE_SIZE-1);
221 		if (len < 0) {
222 			mconsole_reply(req, "Read of file failed", 1, 0);
223 			goto out_free;
224 		}
225 		/* Begin the file content on his own line. */
226 		if (first_chunk) {
227 			mconsole_reply(req, "\n", 0, 1);
228 			first_chunk = 0;
229 		}
230 		if (len == PAGE_SIZE-1) {
231 			buf[len] = '\0';
232 			mconsole_reply(req, buf, 0, 1);
233 		} else {
234 			buf[len] = '\0';
235 			mconsole_reply(req, buf, 0, 0);
236 			break;
237 		}
238 	}
239 
240  out_free:
241 	kfree(buf);
242  out_close:
243 	sys_close(fd);
244  out:
245 	/* nothing */;
246 }
247 
248 #define UML_MCONSOLE_HELPTEXT \
249 "Commands: \n\
250     version - Get kernel version \n\
251     help - Print this message \n\
252     halt - Halt UML \n\
253     reboot - Reboot UML \n\
254     config <dev>=<config> - Add a new device to UML;  \n\
255 	same syntax as command line \n\
256     config <dev> - Query the configuration of a device \n\
257     remove <dev> - Remove a device from UML \n\
258     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
259     cad - invoke the Ctrl-Alt-Del handler \n\
260     stop - pause the UML; it will do nothing until it receives a 'go' \n\
261     go - continue the UML after a 'stop' \n\
262     log <string> - make UML enter <string> into the kernel log\n\
263     proc <file> - returns the contents of the UML's /proc/<file>\n\
264     stack <pid> - returns the stack of the specified pid\n\
265 "
266 
267 void mconsole_help(struct mc_request *req)
268 {
269 	mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
270 }
271 
272 void mconsole_halt(struct mc_request *req)
273 {
274 	mconsole_reply(req, "", 0, 0);
275 	machine_halt();
276 }
277 
278 void mconsole_reboot(struct mc_request *req)
279 {
280 	mconsole_reply(req, "", 0, 0);
281 	machine_restart(NULL);
282 }
283 
284 void mconsole_cad(struct mc_request *req)
285 {
286 	mconsole_reply(req, "", 0, 0);
287 	ctrl_alt_del();
288 }
289 
290 void mconsole_go(struct mc_request *req)
291 {
292 	mconsole_reply(req, "Not stopped", 1, 0);
293 }
294 
295 void mconsole_stop(struct mc_request *req)
296 {
297 	deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
298 	os_set_fd_block(req->originating_fd, 1);
299 	mconsole_reply(req, "stopped", 0, 0);
300 	for (;;) {
301 		if (!mconsole_get_request(req->originating_fd, req))
302 			continue;
303 		if (req->cmd->handler == mconsole_go)
304 			break;
305 		if (req->cmd->handler == mconsole_stop) {
306 			mconsole_reply(req, "Already stopped", 1, 0);
307 			continue;
308 		}
309 		if (req->cmd->handler == mconsole_sysrq) {
310 			struct pt_regs *old_regs;
311 			old_regs = set_irq_regs((struct pt_regs *)&req->regs);
312 			mconsole_sysrq(req);
313 			set_irq_regs(old_regs);
314 			continue;
315 		}
316 		(*req->cmd->handler)(req);
317 	}
318 	os_set_fd_block(req->originating_fd, 0);
319 	reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
320 	mconsole_reply(req, "", 0, 0);
321 }
322 
323 static DEFINE_SPINLOCK(mc_devices_lock);
324 static LIST_HEAD(mconsole_devices);
325 
326 void mconsole_register_dev(struct mc_device *new)
327 {
328 	spin_lock(&mc_devices_lock);
329 	BUG_ON(!list_empty(&new->list));
330 	list_add(&new->list, &mconsole_devices);
331 	spin_unlock(&mc_devices_lock);
332 }
333 
334 static struct mc_device *mconsole_find_dev(char *name)
335 {
336 	struct list_head *ele;
337 	struct mc_device *dev;
338 
339 	list_for_each(ele, &mconsole_devices) {
340 		dev = list_entry(ele, struct mc_device, list);
341 		if (!strncmp(name, dev->name, strlen(dev->name)))
342 			return dev;
343 	}
344 	return NULL;
345 }
346 
347 #define UNPLUGGED_PER_PAGE \
348 	((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
349 
350 struct unplugged_pages {
351 	struct list_head list;
352 	void *pages[UNPLUGGED_PER_PAGE];
353 };
354 
355 static DEFINE_MUTEX(plug_mem_mutex);
356 static unsigned long long unplugged_pages_count = 0;
357 static LIST_HEAD(unplugged_pages);
358 static int unplug_index = UNPLUGGED_PER_PAGE;
359 
360 static int mem_config(char *str, char **error_out)
361 {
362 	unsigned long long diff;
363 	int err = -EINVAL, i, add;
364 	char *ret;
365 
366 	if (str[0] != '=') {
367 		*error_out = "Expected '=' after 'mem'";
368 		goto out;
369 	}
370 
371 	str++;
372 	if (str[0] == '-')
373 		add = 0;
374 	else if (str[0] == '+') {
375 		add = 1;
376 	}
377 	else {
378 		*error_out = "Expected increment to start with '-' or '+'";
379 		goto out;
380 	}
381 
382 	str++;
383 	diff = memparse(str, &ret);
384 	if (*ret != '\0') {
385 		*error_out = "Failed to parse memory increment";
386 		goto out;
387 	}
388 
389 	diff /= PAGE_SIZE;
390 
391 	mutex_lock(&plug_mem_mutex);
392 	for (i = 0; i < diff; i++) {
393 		struct unplugged_pages *unplugged;
394 		void *addr;
395 
396 		if (add) {
397 			if (list_empty(&unplugged_pages))
398 				break;
399 
400 			unplugged = list_entry(unplugged_pages.next,
401 					       struct unplugged_pages, list);
402 			if (unplug_index > 0)
403 				addr = unplugged->pages[--unplug_index];
404 			else {
405 				list_del(&unplugged->list);
406 				addr = unplugged;
407 				unplug_index = UNPLUGGED_PER_PAGE;
408 			}
409 
410 			free_page((unsigned long) addr);
411 			unplugged_pages_count--;
412 		}
413 		else {
414 			struct page *page;
415 
416 			page = alloc_page(GFP_ATOMIC);
417 			if (page == NULL)
418 				break;
419 
420 			unplugged = page_address(page);
421 			if (unplug_index == UNPLUGGED_PER_PAGE) {
422 				list_add(&unplugged->list, &unplugged_pages);
423 				unplug_index = 0;
424 			}
425 			else {
426 				struct list_head *entry = unplugged_pages.next;
427 				addr = unplugged;
428 
429 				unplugged = list_entry(entry,
430 						       struct unplugged_pages,
431 						       list);
432 				err = os_drop_memory(addr, PAGE_SIZE);
433 				if (err) {
434 					printk(KERN_ERR "Failed to release "
435 					       "memory - errno = %d\n", err);
436 					*error_out = "Failed to release memory";
437 					goto out_unlock;
438 				}
439 				unplugged->pages[unplug_index++] = addr;
440 			}
441 
442 			unplugged_pages_count++;
443 		}
444 	}
445 
446 	err = 0;
447 out_unlock:
448 	mutex_unlock(&plug_mem_mutex);
449 out:
450 	return err;
451 }
452 
453 static int mem_get_config(char *name, char *str, int size, char **error_out)
454 {
455 	char buf[sizeof("18446744073709551615")];
456 	int len = 0;
457 
458 	sprintf(buf, "%ld", uml_physmem);
459 	CONFIG_CHUNK(str, size, len, buf, 1);
460 
461 	return len;
462 }
463 
464 static int mem_id(char **str, int *start_out, int *end_out)
465 {
466 	*start_out = 0;
467 	*end_out = 0;
468 
469 	return 0;
470 }
471 
472 static int mem_remove(int n, char **error_out)
473 {
474 	*error_out = "Memory doesn't support the remove operation";
475 	return -EBUSY;
476 }
477 
478 static struct mc_device mem_mc = {
479 	.list		= LIST_HEAD_INIT(mem_mc.list),
480 	.name		= "mem",
481 	.config		= mem_config,
482 	.get_config	= mem_get_config,
483 	.id		= mem_id,
484 	.remove		= mem_remove,
485 };
486 
487 static int __init mem_mc_init(void)
488 {
489 	if (can_drop_memory())
490 		mconsole_register_dev(&mem_mc);
491 	else printk(KERN_ERR "Can't release memory to the host - memory "
492 		    "hotplug won't be supported\n");
493 	return 0;
494 }
495 
496 __initcall(mem_mc_init);
497 
498 #define CONFIG_BUF_SIZE 64
499 
500 static void mconsole_get_config(int (*get_config)(char *, char *, int,
501 						  char **),
502 				struct mc_request *req, char *name)
503 {
504 	char default_buf[CONFIG_BUF_SIZE], *error, *buf;
505 	int n, size;
506 
507 	if (get_config == NULL) {
508 		mconsole_reply(req, "No get_config routine defined", 1, 0);
509 		return;
510 	}
511 
512 	error = NULL;
513 	size = ARRAY_SIZE(default_buf);
514 	buf = default_buf;
515 
516 	while (1) {
517 		n = (*get_config)(name, buf, size, &error);
518 		if (error != NULL) {
519 			mconsole_reply(req, error, 1, 0);
520 			goto out;
521 		}
522 
523 		if (n <= size) {
524 			mconsole_reply(req, buf, 0, 0);
525 			goto out;
526 		}
527 
528 		if (buf != default_buf)
529 			kfree(buf);
530 
531 		size = n;
532 		buf = kmalloc(size, GFP_KERNEL);
533 		if (buf == NULL) {
534 			mconsole_reply(req, "Failed to allocate buffer", 1, 0);
535 			return;
536 		}
537 	}
538  out:
539 	if (buf != default_buf)
540 		kfree(buf);
541 }
542 
543 void mconsole_config(struct mc_request *req)
544 {
545 	struct mc_device *dev;
546 	char *ptr = req->request.data, *name, *error_string = "";
547 	int err;
548 
549 	ptr += strlen("config");
550 	ptr = skip_spaces(ptr);
551 	dev = mconsole_find_dev(ptr);
552 	if (dev == NULL) {
553 		mconsole_reply(req, "Bad configuration option", 1, 0);
554 		return;
555 	}
556 
557 	name = &ptr[strlen(dev->name)];
558 	ptr = name;
559 	while ((*ptr != '=') && (*ptr != '\0'))
560 		ptr++;
561 
562 	if (*ptr == '=') {
563 		err = (*dev->config)(name, &error_string);
564 		mconsole_reply(req, error_string, err, 0);
565 	}
566 	else mconsole_get_config(dev->get_config, req, name);
567 }
568 
569 void mconsole_remove(struct mc_request *req)
570 {
571 	struct mc_device *dev;
572 	char *ptr = req->request.data, *err_msg = "";
573 	char error[256];
574 	int err, start, end, n;
575 
576 	ptr += strlen("remove");
577 	ptr = skip_spaces(ptr);
578 	dev = mconsole_find_dev(ptr);
579 	if (dev == NULL) {
580 		mconsole_reply(req, "Bad remove option", 1, 0);
581 		return;
582 	}
583 
584 	ptr = &ptr[strlen(dev->name)];
585 
586 	err = 1;
587 	n = (*dev->id)(&ptr, &start, &end);
588 	if (n < 0) {
589 		err_msg = "Couldn't parse device number";
590 		goto out;
591 	}
592 	else if ((n < start) || (n > end)) {
593 		sprintf(error, "Invalid device number - must be between "
594 			"%d and %d", start, end);
595 		err_msg = error;
596 		goto out;
597 	}
598 
599 	err_msg = NULL;
600 	err = (*dev->remove)(n, &err_msg);
601 	switch(err) {
602 	case 0:
603 		err_msg = "";
604 		break;
605 	case -ENODEV:
606 		if (err_msg == NULL)
607 			err_msg = "Device doesn't exist";
608 		break;
609 	case -EBUSY:
610 		if (err_msg == NULL)
611 			err_msg = "Device is currently open";
612 		break;
613 	default:
614 		break;
615 	}
616 out:
617 	mconsole_reply(req, err_msg, err, 0);
618 }
619 
620 struct mconsole_output {
621 	struct list_head list;
622 	struct mc_request *req;
623 };
624 
625 static DEFINE_SPINLOCK(client_lock);
626 static LIST_HEAD(clients);
627 static char console_buf[MCONSOLE_MAX_DATA];
628 
629 static void console_write(struct console *console, const char *string,
630 			  unsigned int len)
631 {
632 	struct list_head *ele;
633 	int n;
634 
635 	if (list_empty(&clients))
636 		return;
637 
638 	while (len > 0) {
639 		n = min((size_t) len, ARRAY_SIZE(console_buf));
640 		strncpy(console_buf, string, n);
641 		string += n;
642 		len -= n;
643 
644 		list_for_each(ele, &clients) {
645 			struct mconsole_output *entry;
646 
647 			entry = list_entry(ele, struct mconsole_output, list);
648 			mconsole_reply_len(entry->req, console_buf, n, 0, 1);
649 		}
650 	}
651 }
652 
653 static struct console mc_console = { .name	= "mc",
654 				     .write	= console_write,
655 				     .flags	= CON_ENABLED,
656 				     .index	= -1 };
657 
658 static int mc_add_console(void)
659 {
660 	register_console(&mc_console);
661 	return 0;
662 }
663 
664 late_initcall(mc_add_console);
665 
666 static void with_console(struct mc_request *req, void (*proc)(void *),
667 			 void *arg)
668 {
669 	struct mconsole_output entry;
670 	unsigned long flags;
671 
672 	entry.req = req;
673 	spin_lock_irqsave(&client_lock, flags);
674 	list_add(&entry.list, &clients);
675 	spin_unlock_irqrestore(&client_lock, flags);
676 
677 	(*proc)(arg);
678 
679 	mconsole_reply_len(req, "", 0, 0, 0);
680 
681 	spin_lock_irqsave(&client_lock, flags);
682 	list_del(&entry.list);
683 	spin_unlock_irqrestore(&client_lock, flags);
684 }
685 
686 #ifdef CONFIG_MAGIC_SYSRQ
687 
688 #include <linux/sysrq.h>
689 
690 static void sysrq_proc(void *arg)
691 {
692 	char *op = arg;
693 	handle_sysrq(*op, NULL);
694 }
695 
696 void mconsole_sysrq(struct mc_request *req)
697 {
698 	char *ptr = req->request.data;
699 
700 	ptr += strlen("sysrq");
701 	ptr = skip_spaces(ptr);
702 
703 	/*
704 	 * With 'b', the system will shut down without a chance to reply,
705 	 * so in this case, we reply first.
706 	 */
707 	if (*ptr == 'b')
708 		mconsole_reply(req, "", 0, 0);
709 
710 	with_console(req, sysrq_proc, ptr);
711 }
712 #else
713 void mconsole_sysrq(struct mc_request *req)
714 {
715 	mconsole_reply(req, "Sysrq not compiled in", 1, 0);
716 }
717 #endif
718 
719 static void stack_proc(void *arg)
720 {
721 	struct task_struct *from = current, *to = arg;
722 
723 	to->thread.saved_task = from;
724 	switch_to(from, to, from);
725 }
726 
727 /*
728  * Mconsole stack trace
729  *  Added by Allan Graves, Jeff Dike
730  *  Dumps a stacks registers to the linux console.
731  *  Usage stack <pid>.
732  */
733 void mconsole_stack(struct mc_request *req)
734 {
735 	char *ptr = req->request.data;
736 	int pid_requested= -1;
737 	struct task_struct *to = NULL;
738 
739 	/*
740 	 * Would be nice:
741 	 * 1) Send showregs output to mconsole.
742 	 * 2) Add a way to stack dump all pids.
743 	 */
744 
745 	ptr += strlen("stack");
746 	ptr = skip_spaces(ptr);
747 
748 	/*
749 	 * Should really check for multiple pids or reject bad args here
750 	 */
751 	/* What do the arguments in mconsole_reply mean? */
752 	if (sscanf(ptr, "%d", &pid_requested) == 0) {
753 		mconsole_reply(req, "Please specify a pid", 1, 0);
754 		return;
755 	}
756 
757 	to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
758 	if ((to == NULL) || (pid_requested == 0)) {
759 		mconsole_reply(req, "Couldn't find that pid", 1, 0);
760 		return;
761 	}
762 	with_console(req, stack_proc, to);
763 }
764 
765 /*
766  * Changed by mconsole_setup, which is __setup, and called before SMP is
767  * active.
768  */
769 static char *notify_socket = NULL;
770 
771 static int __init mconsole_init(void)
772 {
773 	/* long to avoid size mismatch warnings from gcc */
774 	long sock;
775 	int err;
776 	char file[UNIX_PATH_MAX];
777 
778 	if (umid_file_name("mconsole", file, sizeof(file)))
779 		return -1;
780 	snprintf(mconsole_socket_name, sizeof(file), "%s", file);
781 
782 	sock = os_create_unix_socket(file, sizeof(file), 1);
783 	if (sock < 0) {
784 		printk(KERN_ERR "Failed to initialize management console\n");
785 		return 1;
786 	}
787 	if (os_set_fd_block(sock, 0))
788 		goto out;
789 
790 	register_reboot_notifier(&reboot_notifier);
791 
792 	err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
793 			     IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
794 			     "mconsole", (void *)sock);
795 	if (err) {
796 		printk(KERN_ERR "Failed to get IRQ for management console\n");
797 		goto out;
798 	}
799 
800 	if (notify_socket != NULL) {
801 		notify_socket = kstrdup(notify_socket, GFP_KERNEL);
802 		if (notify_socket != NULL)
803 			mconsole_notify(notify_socket, MCONSOLE_SOCKET,
804 					mconsole_socket_name,
805 					strlen(mconsole_socket_name) + 1);
806 		else printk(KERN_ERR "mconsole_setup failed to strdup "
807 			    "string\n");
808 	}
809 
810 	printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
811 	       MCONSOLE_VERSION, mconsole_socket_name);
812 	return 0;
813 
814  out:
815 	os_close_file(sock);
816 	return 1;
817 }
818 
819 __initcall(mconsole_init);
820 
821 static ssize_t mconsole_proc_write(struct file *file,
822 		const char __user *buffer, size_t count, loff_t *pos)
823 {
824 	char *buf;
825 
826 	buf = kmalloc(count + 1, GFP_KERNEL);
827 	if (buf == NULL)
828 		return -ENOMEM;
829 
830 	if (copy_from_user(buf, buffer, count)) {
831 		count = -EFAULT;
832 		goto out;
833 	}
834 
835 	buf[count] = '\0';
836 
837 	mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
838  out:
839 	kfree(buf);
840 	return count;
841 }
842 
843 static const struct file_operations mconsole_proc_fops = {
844 	.owner		= THIS_MODULE,
845 	.write		= mconsole_proc_write,
846 };
847 
848 static int create_proc_mconsole(void)
849 {
850 	struct proc_dir_entry *ent;
851 
852 	if (notify_socket == NULL)
853 		return 0;
854 
855 	ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
856 	if (ent == NULL) {
857 		printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
858 		       "failed\n");
859 		return 0;
860 	}
861 	return 0;
862 }
863 
864 static DEFINE_SPINLOCK(notify_spinlock);
865 
866 void lock_notify(void)
867 {
868 	spin_lock(&notify_spinlock);
869 }
870 
871 void unlock_notify(void)
872 {
873 	spin_unlock(&notify_spinlock);
874 }
875 
876 __initcall(create_proc_mconsole);
877 
878 #define NOTIFY "notify:"
879 
880 static int mconsole_setup(char *str)
881 {
882 	if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
883 		str += strlen(NOTIFY);
884 		notify_socket = str;
885 	}
886 	else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
887 	return 1;
888 }
889 
890 __setup("mconsole=", mconsole_setup);
891 
892 __uml_help(mconsole_setup,
893 "mconsole=notify:<socket>\n"
894 "    Requests that the mconsole driver send a message to the named Unix\n"
895 "    socket containing the name of the mconsole socket.  This also serves\n"
896 "    to notify outside processes when UML has booted far enough to respond\n"
897 "    to mconsole requests.\n\n"
898 );
899 
900 static int notify_panic(struct notifier_block *self, unsigned long unused1,
901 			void *ptr)
902 {
903 	char *message = ptr;
904 
905 	if (notify_socket == NULL)
906 		return 0;
907 
908 	mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
909 			strlen(message) + 1);
910 	return 0;
911 }
912 
913 static struct notifier_block panic_exit_notifier = {
914 	.notifier_call 		= notify_panic,
915 	.next 			= NULL,
916 	.priority 		= 1
917 };
918 
919 static int add_notifier(void)
920 {
921 	atomic_notifier_chain_register(&panic_notifier_list,
922 			&panic_exit_notifier);
923 	return 0;
924 }
925 
926 __initcall(add_notifier);
927 
928 char *mconsole_notify_socket(void)
929 {
930 	return notify_socket;
931 }
932 
933 EXPORT_SYMBOL(mconsole_notify_socket);
934