xref: /openbmc/linux/arch/um/drivers/mconsole_kern.c (revision 96de0e252cedffad61b3cb5e05662c591898e69a)
1 /*
2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3  * Copyright (C) 2001 - 2007 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/interrupt.h"
10 #include "linux/list.h"
11 #include "linux/mm.h"
12 #include "linux/module.h"
13 #include "linux/notifier.h"
14 #include "linux/reboot.h"
15 #include "linux/proc_fs.h"
16 #include "linux/slab.h"
17 #include "linux/syscalls.h"
18 #include "linux/utsname.h"
19 #include "linux/workqueue.h"
20 #include "asm/uaccess.h"
21 #include "init.h"
22 #include "irq_kern.h"
23 #include "irq_user.h"
24 #include "kern_util.h"
25 #include "mconsole.h"
26 #include "mconsole_kern.h"
27 #include "os.h"
28 
29 static int do_unlink_socket(struct notifier_block *notifier,
30 			    unsigned long what, void *data)
31 {
32 	return mconsole_unlink_socket();
33 }
34 
35 
36 static struct notifier_block reboot_notifier = {
37 	.notifier_call		= do_unlink_socket,
38 	.priority		= 0,
39 };
40 
41 /* Safe without explicit locking for now.  Tasklets provide their own
42  * locking, and the interrupt handler is safe because it can't interrupt
43  * itself and it can only happen on CPU 0.
44  */
45 
46 static LIST_HEAD(mc_requests);
47 
48 static void mc_work_proc(struct work_struct *unused)
49 {
50 	struct mconsole_entry *req;
51 	unsigned long flags;
52 
53 	while (!list_empty(&mc_requests)) {
54 		local_irq_save(flags);
55 		req = list_entry(mc_requests.next, struct mconsole_entry, list);
56 		list_del(&req->list);
57 		local_irq_restore(flags);
58 		req->request.cmd->handler(&req->request);
59 		kfree(req);
60 	}
61 }
62 
63 static DECLARE_WORK(mconsole_work, mc_work_proc);
64 
65 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
66 {
67 	/* long to avoid size mismatch warnings from gcc */
68 	long fd;
69 	struct mconsole_entry *new;
70 	static struct mc_request req;	/* that's OK */
71 
72 	fd = (long) dev_id;
73 	while (mconsole_get_request(fd, &req)) {
74 		if (req.cmd->context == MCONSOLE_INTR)
75 			(*req.cmd->handler)(&req);
76 		else {
77 			new = kmalloc(sizeof(*new), GFP_NOWAIT);
78 			if (new == NULL)
79 				mconsole_reply(&req, "Out of memory", 1, 0);
80 			else {
81 				new->request = req;
82 				new->request.regs = get_irq_regs()->regs;
83 				list_add(&new->list, &mc_requests);
84 			}
85 		}
86 	}
87 	if (!list_empty(&mc_requests))
88 		schedule_work(&mconsole_work);
89 	reactivate_fd(fd, MCONSOLE_IRQ);
90 	return IRQ_HANDLED;
91 }
92 
93 void mconsole_version(struct mc_request *req)
94 {
95 	char version[256];
96 
97 	sprintf(version, "%s %s %s %s %s", utsname()->sysname,
98 		utsname()->nodename, utsname()->release, utsname()->version,
99 		utsname()->machine);
100 	mconsole_reply(req, version, 0, 0);
101 }
102 
103 void mconsole_log(struct mc_request *req)
104 {
105 	int len;
106 	char *ptr = req->request.data;
107 
108 	ptr += strlen("log ");
109 
110 	len = req->len - (ptr - req->request.data);
111 	printk(KERN_WARNING "%.*s", len, ptr);
112 	mconsole_reply(req, "", 0, 0);
113 }
114 
115 /* This is a more convoluted version of mconsole_proc, which has some stability
116  * problems; however, we need it fixed, because it is expected that UML users
117  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
118  * show the real procfs content, not the ones from hppfs.*/
119 #if 0
120 void mconsole_proc(struct mc_request *req)
121 {
122 	struct nameidata nd;
123 	struct file_system_type *proc;
124 	struct super_block *super;
125 	struct file *file;
126 	int n, err;
127 	char *ptr = req->request.data, *buf;
128 
129 	ptr += strlen("proc");
130 	while (isspace(*ptr)) ptr++;
131 
132 	proc = get_fs_type("proc");
133 	if (proc == NULL) {
134 		mconsole_reply(req, "procfs not registered", 1, 0);
135 		goto out;
136 	}
137 
138 	super = (*proc->get_sb)(proc, 0, NULL, NULL);
139 	put_filesystem(proc);
140 	if (super == NULL) {
141 		mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
142 		goto out;
143 	}
144 	up_write(&super->s_umount);
145 
146 	nd.dentry = super->s_root;
147 	nd.mnt = NULL;
148 	nd.flags = O_RDONLY + 1;
149 	nd.last_type = LAST_ROOT;
150 
151 	/* START: it was experienced that the stability problems are closed
152 	 * if commenting out these two calls + the below read cycle. To
153 	 * make UML crash again, it was enough to readd either one.*/
154 	err = link_path_walk(ptr, &nd);
155 	if (err) {
156 		mconsole_reply(req, "Failed to look up file", 1, 0);
157 		goto out_kill;
158 	}
159 
160 	file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
161 	if (IS_ERR(file)) {
162 		mconsole_reply(req, "Failed to open file", 1, 0);
163 		goto out_kill;
164 	}
165 	/*END*/
166 
167 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
168 	if (buf == NULL) {
169 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
170 		goto out_fput;
171 	}
172 
173 	if ((file->f_op != NULL) && (file->f_op->read != NULL)) {
174 		do {
175 			n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
176 						&file->f_pos);
177 			if (n >= 0) {
178 				buf[n] = '\0';
179 				mconsole_reply(req, buf, 0, (n > 0));
180 			}
181 			else {
182 				mconsole_reply(req, "Read of file failed",
183 					       1, 0);
184 				goto out_free;
185 			}
186 		} while (n > 0);
187 	}
188 	else mconsole_reply(req, "", 0, 0);
189 
190  out_free:
191 	kfree(buf);
192  out_fput:
193 	fput(file);
194  out_kill:
195 	deactivate_super(super);
196  out: ;
197 }
198 #endif
199 
200 void mconsole_proc(struct mc_request *req)
201 {
202 	char path[64];
203 	char *buf;
204 	int len;
205 	int fd;
206 	int first_chunk = 1;
207 	char *ptr = req->request.data;
208 
209 	ptr += strlen("proc");
210 	while (isspace(*ptr))
211 		ptr++;
212 	snprintf(path, sizeof(path), "/proc/%s", ptr);
213 
214 	fd = sys_open(path, 0, 0);
215 	if (fd < 0) {
216 		mconsole_reply(req, "Failed to open file", 1, 0);
217 		printk(KERN_ERR "open %s: %d\n",path,fd);
218 		goto out;
219 	}
220 
221 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
222 	if (buf == NULL) {
223 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
224 		goto out_close;
225 	}
226 
227 	for (;;) {
228 		len = sys_read(fd, buf, PAGE_SIZE-1);
229 		if (len < 0) {
230 			mconsole_reply(req, "Read of file failed", 1, 0);
231 			goto out_free;
232 		}
233 		/* Begin the file content on his own line. */
234 		if (first_chunk) {
235 			mconsole_reply(req, "\n", 0, 1);
236 			first_chunk = 0;
237 		}
238 		if (len == PAGE_SIZE-1) {
239 			buf[len] = '\0';
240 			mconsole_reply(req, buf, 0, 1);
241 		} else {
242 			buf[len] = '\0';
243 			mconsole_reply(req, buf, 0, 0);
244 			break;
245 		}
246 	}
247 
248  out_free:
249 	kfree(buf);
250  out_close:
251 	sys_close(fd);
252  out:
253 	/* nothing */;
254 }
255 
256 #define UML_MCONSOLE_HELPTEXT \
257 "Commands: \n\
258     version - Get kernel version \n\
259     help - Print this message \n\
260     halt - Halt UML \n\
261     reboot - Reboot UML \n\
262     config <dev>=<config> - Add a new device to UML;  \n\
263 	same syntax as command line \n\
264     config <dev> - Query the configuration of a device \n\
265     remove <dev> - Remove a device from UML \n\
266     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
267     cad - invoke the Ctrl-Alt-Del handler \n\
268     stop - pause the UML; it will do nothing until it receives a 'go' \n\
269     go - continue the UML after a 'stop' \n\
270     log <string> - make UML enter <string> into the kernel log\n\
271     proc <file> - returns the contents of the UML's /proc/<file>\n\
272     stack <pid> - returns the stack of the specified pid\n\
273 "
274 
275 void mconsole_help(struct mc_request *req)
276 {
277 	mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
278 }
279 
280 void mconsole_halt(struct mc_request *req)
281 {
282 	mconsole_reply(req, "", 0, 0);
283 	machine_halt();
284 }
285 
286 void mconsole_reboot(struct mc_request *req)
287 {
288 	mconsole_reply(req, "", 0, 0);
289 	machine_restart(NULL);
290 }
291 
292 void mconsole_cad(struct mc_request *req)
293 {
294 	mconsole_reply(req, "", 0, 0);
295 	ctrl_alt_del();
296 }
297 
298 void mconsole_go(struct mc_request *req)
299 {
300 	mconsole_reply(req, "Not stopped", 1, 0);
301 }
302 
303 void mconsole_stop(struct mc_request *req)
304 {
305 	deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
306 	os_set_fd_block(req->originating_fd, 1);
307 	mconsole_reply(req, "stopped", 0, 0);
308 	while (mconsole_get_request(req->originating_fd, req)) {
309 		if (req->cmd->handler == mconsole_go)
310 			break;
311 		if (req->cmd->handler == mconsole_stop) {
312 			mconsole_reply(req, "Already stopped", 1, 0);
313 			continue;
314 		}
315 		if (req->cmd->handler == mconsole_sysrq) {
316 			struct pt_regs *old_regs;
317 			old_regs = set_irq_regs((struct pt_regs *)&req->regs);
318 			mconsole_sysrq(req);
319 			set_irq_regs(old_regs);
320 			continue;
321 		}
322 		(*req->cmd->handler)(req);
323 	}
324 	os_set_fd_block(req->originating_fd, 0);
325 	reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
326 	mconsole_reply(req, "", 0, 0);
327 }
328 
329 static DEFINE_SPINLOCK(mc_devices_lock);
330 static LIST_HEAD(mconsole_devices);
331 
332 void mconsole_register_dev(struct mc_device *new)
333 {
334 	spin_lock(&mc_devices_lock);
335 	BUG_ON(!list_empty(&new->list));
336 	list_add(&new->list, &mconsole_devices);
337 	spin_unlock(&mc_devices_lock);
338 }
339 
340 static struct mc_device *mconsole_find_dev(char *name)
341 {
342 	struct list_head *ele;
343 	struct mc_device *dev;
344 
345 	list_for_each(ele, &mconsole_devices) {
346 		dev = list_entry(ele, struct mc_device, list);
347 		if (!strncmp(name, dev->name, strlen(dev->name)))
348 			return dev;
349 	}
350 	return NULL;
351 }
352 
353 #define UNPLUGGED_PER_PAGE \
354 	((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
355 
356 struct unplugged_pages {
357 	struct list_head list;
358 	void *pages[UNPLUGGED_PER_PAGE];
359 };
360 
361 static DECLARE_MUTEX(plug_mem_mutex);
362 static unsigned long long unplugged_pages_count = 0;
363 static LIST_HEAD(unplugged_pages);
364 static int unplug_index = UNPLUGGED_PER_PAGE;
365 
366 static int mem_config(char *str, char **error_out)
367 {
368 	unsigned long long diff;
369 	int err = -EINVAL, i, add;
370 	char *ret;
371 
372 	if (str[0] != '=') {
373 		*error_out = "Expected '=' after 'mem'";
374 		goto out;
375 	}
376 
377 	str++;
378 	if (str[0] == '-')
379 		add = 0;
380 	else if (str[0] == '+') {
381 		add = 1;
382 	}
383 	else {
384 		*error_out = "Expected increment to start with '-' or '+'";
385 		goto out;
386 	}
387 
388 	str++;
389 	diff = memparse(str, &ret);
390 	if (*ret != '\0') {
391 		*error_out = "Failed to parse memory increment";
392 		goto out;
393 	}
394 
395 	diff /= PAGE_SIZE;
396 
397 	down(&plug_mem_mutex);
398 	for (i = 0; i < diff; i++) {
399 		struct unplugged_pages *unplugged;
400 		void *addr;
401 
402 		if (add) {
403 			if (list_empty(&unplugged_pages))
404 				break;
405 
406 			unplugged = list_entry(unplugged_pages.next,
407 					       struct unplugged_pages, list);
408 			if (unplug_index > 0)
409 				addr = unplugged->pages[--unplug_index];
410 			else {
411 				list_del(&unplugged->list);
412 				addr = unplugged;
413 				unplug_index = UNPLUGGED_PER_PAGE;
414 			}
415 
416 			free_page((unsigned long) addr);
417 			unplugged_pages_count--;
418 		}
419 		else {
420 			struct page *page;
421 
422 			page = alloc_page(GFP_ATOMIC);
423 			if (page == NULL)
424 				break;
425 
426 			unplugged = page_address(page);
427 			if (unplug_index == UNPLUGGED_PER_PAGE) {
428 				list_add(&unplugged->list, &unplugged_pages);
429 				unplug_index = 0;
430 			}
431 			else {
432 				struct list_head *entry = unplugged_pages.next;
433 				addr = unplugged;
434 
435 				unplugged = list_entry(entry,
436 						       struct unplugged_pages,
437 						       list);
438 				err = os_drop_memory(addr, PAGE_SIZE);
439 				if (err) {
440 					printk(KERN_ERR "Failed to release "
441 					       "memory - errno = %d\n", err);
442 					*error_out = "Failed to release memory";
443 					goto out_unlock;
444 				}
445 				unplugged->pages[unplug_index++] = addr;
446 			}
447 
448 			unplugged_pages_count++;
449 		}
450 	}
451 
452 	err = 0;
453 out_unlock:
454 	up(&plug_mem_mutex);
455 out:
456 	return err;
457 }
458 
459 static int mem_get_config(char *name, char *str, int size, char **error_out)
460 {
461 	char buf[sizeof("18446744073709551615")];
462 	int len = 0;
463 
464 	sprintf(buf, "%ld", uml_physmem);
465 	CONFIG_CHUNK(str, size, len, buf, 1);
466 
467 	return len;
468 }
469 
470 static int mem_id(char **str, int *start_out, int *end_out)
471 {
472 	*start_out = 0;
473 	*end_out = 0;
474 
475 	return 0;
476 }
477 
478 static int mem_remove(int n, char **error_out)
479 {
480 	*error_out = "Memory doesn't support the remove operation";
481 	return -EBUSY;
482 }
483 
484 static struct mc_device mem_mc = {
485 	.list		= LIST_HEAD_INIT(mem_mc.list),
486 	.name		= "mem",
487 	.config		= mem_config,
488 	.get_config	= mem_get_config,
489 	.id		= mem_id,
490 	.remove		= mem_remove,
491 };
492 
493 static int __init mem_mc_init(void)
494 {
495 	if (can_drop_memory())
496 		mconsole_register_dev(&mem_mc);
497 	else printk(KERN_ERR "Can't release memory to the host - memory "
498 		    "hotplug won't be supported\n");
499 	return 0;
500 }
501 
502 __initcall(mem_mc_init);
503 
504 #define CONFIG_BUF_SIZE 64
505 
506 static void mconsole_get_config(int (*get_config)(char *, char *, int,
507 						  char **),
508 				struct mc_request *req, char *name)
509 {
510 	char default_buf[CONFIG_BUF_SIZE], *error, *buf;
511 	int n, size;
512 
513 	if (get_config == NULL) {
514 		mconsole_reply(req, "No get_config routine defined", 1, 0);
515 		return;
516 	}
517 
518 	error = NULL;
519 	size = ARRAY_SIZE(default_buf);
520 	buf = default_buf;
521 
522 	while (1) {
523 		n = (*get_config)(name, buf, size, &error);
524 		if (error != NULL) {
525 			mconsole_reply(req, error, 1, 0);
526 			goto out;
527 		}
528 
529 		if (n <= size) {
530 			mconsole_reply(req, buf, 0, 0);
531 			goto out;
532 		}
533 
534 		if (buf != default_buf)
535 			kfree(buf);
536 
537 		size = n;
538 		buf = kmalloc(size, GFP_KERNEL);
539 		if (buf == NULL) {
540 			mconsole_reply(req, "Failed to allocate buffer", 1, 0);
541 			return;
542 		}
543 	}
544  out:
545 	if (buf != default_buf)
546 		kfree(buf);
547 }
548 
549 void mconsole_config(struct mc_request *req)
550 {
551 	struct mc_device *dev;
552 	char *ptr = req->request.data, *name, *error_string = "";
553 	int err;
554 
555 	ptr += strlen("config");
556 	while (isspace(*ptr))
557 		ptr++;
558 	dev = mconsole_find_dev(ptr);
559 	if (dev == NULL) {
560 		mconsole_reply(req, "Bad configuration option", 1, 0);
561 		return;
562 	}
563 
564 	name = &ptr[strlen(dev->name)];
565 	ptr = name;
566 	while ((*ptr != '=') && (*ptr != '\0'))
567 		ptr++;
568 
569 	if (*ptr == '=') {
570 		err = (*dev->config)(name, &error_string);
571 		mconsole_reply(req, error_string, err, 0);
572 	}
573 	else mconsole_get_config(dev->get_config, req, name);
574 }
575 
576 void mconsole_remove(struct mc_request *req)
577 {
578 	struct mc_device *dev;
579 	char *ptr = req->request.data, *err_msg = "";
580 	char error[256];
581 	int err, start, end, n;
582 
583 	ptr += strlen("remove");
584 	while (isspace(*ptr)) ptr++;
585 	dev = mconsole_find_dev(ptr);
586 	if (dev == NULL) {
587 		mconsole_reply(req, "Bad remove option", 1, 0);
588 		return;
589 	}
590 
591 	ptr = &ptr[strlen(dev->name)];
592 
593 	err = 1;
594 	n = (*dev->id)(&ptr, &start, &end);
595 	if (n < 0) {
596 		err_msg = "Couldn't parse device number";
597 		goto out;
598 	}
599 	else if ((n < start) || (n > end)) {
600 		sprintf(error, "Invalid device number - must be between "
601 			"%d and %d", start, end);
602 		err_msg = error;
603 		goto out;
604 	}
605 
606 	err_msg = NULL;
607 	err = (*dev->remove)(n, &err_msg);
608 	switch(err) {
609 	case 0:
610 		err_msg = "";
611 		break;
612 	case -ENODEV:
613 		if (err_msg == NULL)
614 			err_msg = "Device doesn't exist";
615 		break;
616 	case -EBUSY:
617 		if (err_msg == NULL)
618 			err_msg = "Device is currently open";
619 		break;
620 	default:
621 		break;
622 	}
623 out:
624 	mconsole_reply(req, err_msg, err, 0);
625 }
626 
627 struct mconsole_output {
628 	struct list_head list;
629 	struct mc_request *req;
630 };
631 
632 static DEFINE_SPINLOCK(client_lock);
633 static LIST_HEAD(clients);
634 static char console_buf[MCONSOLE_MAX_DATA];
635 
636 static void console_write(struct console *console, const char *string,
637 			  unsigned int len)
638 {
639 	struct list_head *ele;
640 	int n;
641 
642 	if (list_empty(&clients))
643 		return;
644 
645 	while (len > 0) {
646 		n = min((size_t) len, ARRAY_SIZE(console_buf));
647 		strncpy(console_buf, string, n);
648 		string += n;
649 		len -= n;
650 
651 		list_for_each(ele, &clients) {
652 			struct mconsole_output *entry;
653 
654 			entry = list_entry(ele, struct mconsole_output, list);
655 			mconsole_reply_len(entry->req, console_buf, n, 0, 1);
656 		}
657 	}
658 }
659 
660 static struct console mc_console = { .name	= "mc",
661 				     .write	= console_write,
662 				     .flags	= CON_ENABLED,
663 				     .index	= -1 };
664 
665 static int mc_add_console(void)
666 {
667 	register_console(&mc_console);
668 	return 0;
669 }
670 
671 late_initcall(mc_add_console);
672 
673 static void with_console(struct mc_request *req, void (*proc)(void *),
674 			 void *arg)
675 {
676 	struct mconsole_output entry;
677 	unsigned long flags;
678 
679 	entry.req = req;
680 	spin_lock_irqsave(&client_lock, flags);
681 	list_add(&entry.list, &clients);
682 	spin_unlock_irqrestore(&client_lock, flags);
683 
684 	(*proc)(arg);
685 
686 	mconsole_reply_len(req, "", 0, 0, 0);
687 
688 	spin_lock_irqsave(&client_lock, flags);
689 	list_del(&entry.list);
690 	spin_unlock_irqrestore(&client_lock, flags);
691 }
692 
693 #ifdef CONFIG_MAGIC_SYSRQ
694 
695 #include <linux/sysrq.h>
696 
697 static void sysrq_proc(void *arg)
698 {
699 	char *op = arg;
700 	handle_sysrq(*op, NULL);
701 }
702 
703 void mconsole_sysrq(struct mc_request *req)
704 {
705 	char *ptr = req->request.data;
706 
707 	ptr += strlen("sysrq");
708 	while (isspace(*ptr)) ptr++;
709 
710 	/*
711 	 * With 'b', the system will shut down without a chance to reply,
712 	 * so in this case, we reply first.
713 	 */
714 	if (*ptr == 'b')
715 		mconsole_reply(req, "", 0, 0);
716 
717 	with_console(req, sysrq_proc, ptr);
718 }
719 #else
720 void mconsole_sysrq(struct mc_request *req)
721 {
722 	mconsole_reply(req, "Sysrq not compiled in", 1, 0);
723 }
724 #endif
725 
726 static void stack_proc(void *arg)
727 {
728 	struct task_struct *from = current, *to = arg;
729 
730 	to->thread.saved_task = from;
731 	switch_to(from, to, from);
732 }
733 
734 /*
735  * Mconsole stack trace
736  *  Added by Allan Graves, Jeff Dike
737  *  Dumps a stacks registers to the linux console.
738  *  Usage stack <pid>.
739  */
740 void mconsole_stack(struct mc_request *req)
741 {
742 	char *ptr = req->request.data;
743 	int pid_requested= -1;
744 	struct task_struct *from = NULL;
745 	struct task_struct *to = NULL;
746 
747 	/*
748 	 * Would be nice:
749 	 * 1) Send showregs output to mconsole.
750 	 * 2) Add a way to stack dump all pids.
751 	 */
752 
753 	ptr += strlen("stack");
754 	while (isspace(*ptr))
755 		ptr++;
756 
757 	/*
758 	 * Should really check for multiple pids or reject bad args here
759 	 */
760 	/* What do the arguments in mconsole_reply mean? */
761 	if (sscanf(ptr, "%d", &pid_requested) == 0) {
762 		mconsole_reply(req, "Please specify a pid", 1, 0);
763 		return;
764 	}
765 
766 	from = current;
767 
768 	to = find_task_by_pid(pid_requested);
769 	if ((to == NULL) || (pid_requested == 0)) {
770 		mconsole_reply(req, "Couldn't find that pid", 1, 0);
771 		return;
772 	}
773 	with_console(req, stack_proc, to);
774 }
775 
776 /*
777  * Changed by mconsole_setup, which is __setup, and called before SMP is
778  * active.
779  */
780 static char *notify_socket = NULL;
781 
782 static int __init mconsole_init(void)
783 {
784 	/* long to avoid size mismatch warnings from gcc */
785 	long sock;
786 	int err;
787 	char file[256];
788 
789 	if (umid_file_name("mconsole", file, sizeof(file)))
790 		return -1;
791 	snprintf(mconsole_socket_name, sizeof(file), "%s", file);
792 
793 	sock = os_create_unix_socket(file, sizeof(file), 1);
794 	if (sock < 0) {
795 		printk(KERN_ERR "Failed to initialize management console\n");
796 		return 1;
797 	}
798 
799 	register_reboot_notifier(&reboot_notifier);
800 
801 	err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
802 			     IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
803 			     "mconsole", (void *)sock);
804 	if (err) {
805 		printk(KERN_ERR "Failed to get IRQ for management console\n");
806 		return 1;
807 	}
808 
809 	if (notify_socket != NULL) {
810 		notify_socket = kstrdup(notify_socket, GFP_KERNEL);
811 		if (notify_socket != NULL)
812 			mconsole_notify(notify_socket, MCONSOLE_SOCKET,
813 					mconsole_socket_name,
814 					strlen(mconsole_socket_name) + 1);
815 		else printk(KERN_ERR "mconsole_setup failed to strdup "
816 			    "string\n");
817 	}
818 
819 	printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
820 	       MCONSOLE_VERSION, mconsole_socket_name);
821 	return 0;
822 }
823 
824 __initcall(mconsole_init);
825 
826 static int write_proc_mconsole(struct file *file, const char __user *buffer,
827 			       unsigned long count, void *data)
828 {
829 	char *buf;
830 
831 	buf = kmalloc(count + 1, GFP_KERNEL);
832 	if (buf == NULL)
833 		return -ENOMEM;
834 
835 	if (copy_from_user(buf, buffer, count)) {
836 		count = -EFAULT;
837 		goto out;
838 	}
839 
840 	buf[count] = '\0';
841 
842 	mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
843  out:
844 	kfree(buf);
845 	return count;
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 = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
856 	if (ent == NULL) {
857 		printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
858 		       "failed\n");
859 		return 0;
860 	}
861 
862 	ent->read_proc = NULL;
863 	ent->write_proc = write_proc_mconsole;
864 	return 0;
865 }
866 
867 static DEFINE_SPINLOCK(notify_spinlock);
868 
869 void lock_notify(void)
870 {
871 	spin_lock(&notify_spinlock);
872 }
873 
874 void unlock_notify(void)
875 {
876 	spin_unlock(&notify_spinlock);
877 }
878 
879 __initcall(create_proc_mconsole);
880 
881 #define NOTIFY "notify:"
882 
883 static int mconsole_setup(char *str)
884 {
885 	if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
886 		str += strlen(NOTIFY);
887 		notify_socket = str;
888 	}
889 	else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
890 	return 1;
891 }
892 
893 __setup("mconsole=", mconsole_setup);
894 
895 __uml_help(mconsole_setup,
896 "mconsole=notify:<socket>\n"
897 "    Requests that the mconsole driver send a message to the named Unix\n"
898 "    socket containing the name of the mconsole socket.  This also serves\n"
899 "    to notify outside processes when UML has booted far enough to respond\n"
900 "    to mconsole requests.\n\n"
901 );
902 
903 static int notify_panic(struct notifier_block *self, unsigned long unused1,
904 			void *ptr)
905 {
906 	char *message = ptr;
907 
908 	if (notify_socket == NULL)
909 		return 0;
910 
911 	mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
912 			strlen(message) + 1);
913 	return 0;
914 }
915 
916 static struct notifier_block panic_exit_notifier = {
917 	.notifier_call 		= notify_panic,
918 	.next 			= NULL,
919 	.priority 		= 1
920 };
921 
922 static int add_notifier(void)
923 {
924 	atomic_notifier_chain_register(&panic_notifier_list,
925 			&panic_exit_notifier);
926 	return 0;
927 }
928 
929 __initcall(add_notifier);
930 
931 char *mconsole_notify_socket(void)
932 {
933 	return notify_socket;
934 }
935 
936 EXPORT_SYMBOL(mconsole_notify_socket);
937