xref: /linux/arch/um/drivers/mconsole_kern.c (revision ba6e8564f459211117ce300eae2c7fdd23befe34)
1 /*
2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3  * Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
4  * Licensed under the GPL
5  */
6 
7 #include "linux/kernel.h"
8 #include "linux/slab.h"
9 #include "linux/init.h"
10 #include "linux/notifier.h"
11 #include "linux/reboot.h"
12 #include "linux/utsname.h"
13 #include "linux/ctype.h"
14 #include "linux/interrupt.h"
15 #include "linux/sysrq.h"
16 #include "linux/workqueue.h"
17 #include "linux/module.h"
18 #include "linux/file.h"
19 #include "linux/fs.h"
20 #include "linux/namei.h"
21 #include "linux/proc_fs.h"
22 #include "linux/syscalls.h"
23 #include "linux/list.h"
24 #include "linux/mm.h"
25 #include "linux/console.h"
26 #include "asm/irq.h"
27 #include "asm/uaccess.h"
28 #include "user_util.h"
29 #include "kern_util.h"
30 #include "kern.h"
31 #include "mconsole.h"
32 #include "mconsole_kern.h"
33 #include "irq_user.h"
34 #include "init.h"
35 #include "os.h"
36 #include "irq_kern.h"
37 #include "choose-mode.h"
38 
39 static int do_unlink_socket(struct notifier_block *notifier,
40 			    unsigned long what, void *data)
41 {
42 	return(mconsole_unlink_socket());
43 }
44 
45 
46 static struct notifier_block reboot_notifier = {
47 	.notifier_call		= do_unlink_socket,
48 	.priority		= 0,
49 };
50 
51 /* Safe without explicit locking for now.  Tasklets provide their own
52  * locking, and the interrupt handler is safe because it can't interrupt
53  * itself and it can only happen on CPU 0.
54  */
55 
56 static LIST_HEAD(mc_requests);
57 
58 static void mc_work_proc(struct work_struct *unused)
59 {
60 	struct mconsole_entry *req;
61 	unsigned long flags;
62 
63 	while(!list_empty(&mc_requests)){
64 		local_irq_save(flags);
65 		req = list_entry(mc_requests.next, struct mconsole_entry,
66 				 list);
67 		list_del(&req->list);
68 		local_irq_restore(flags);
69 		req->request.cmd->handler(&req->request);
70 		kfree(req);
71 	}
72 }
73 
74 static DECLARE_WORK(mconsole_work, mc_work_proc);
75 
76 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
77 {
78 	/* long to avoid size mismatch warnings from gcc */
79 	long fd;
80 	struct mconsole_entry *new;
81 	static struct mc_request req;	/* that's OK */
82 
83 	fd = (long) dev_id;
84 	while (mconsole_get_request(fd, &req)){
85 		if(req.cmd->context == MCONSOLE_INTR)
86 			(*req.cmd->handler)(&req);
87 		else {
88 			new = kmalloc(sizeof(*new), GFP_NOWAIT);
89 			if(new == NULL)
90 				mconsole_reply(&req, "Out of memory", 1, 0);
91 			else {
92 				new->request = req;
93 				new->request.regs = get_irq_regs()->regs;
94 				list_add(&new->list, &mc_requests);
95 			}
96 		}
97 	}
98 	if(!list_empty(&mc_requests))
99 		schedule_work(&mconsole_work);
100 	reactivate_fd(fd, MCONSOLE_IRQ);
101 	return(IRQ_HANDLED);
102 }
103 
104 void mconsole_version(struct mc_request *req)
105 {
106 	char version[256];
107 
108 	sprintf(version, "%s %s %s %s %s", utsname()->sysname,
109 		utsname()->nodename, utsname()->release,
110 		utsname()->version, utsname()->machine);
111 	mconsole_reply(req, version, 0, 0);
112 }
113 
114 void mconsole_log(struct mc_request *req)
115 {
116 	int len;
117 	char *ptr = req->request.data;
118 
119 	ptr += strlen("log ");
120 
121 	len = req->len - (ptr - req->request.data);
122 	printk("%.*s", len, ptr);
123 	mconsole_reply(req, "", 0, 0);
124 }
125 
126 /* This is a more convoluted version of mconsole_proc, which has some stability
127  * problems; however, we need it fixed, because it is expected that UML users
128  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
129  * show the real procfs content, not the ones from hppfs.*/
130 #if 0
131 void mconsole_proc(struct mc_request *req)
132 {
133 	struct nameidata nd;
134 	struct file_system_type *proc;
135 	struct super_block *super;
136 	struct file *file;
137 	int n, err;
138 	char *ptr = req->request.data, *buf;
139 
140 	ptr += strlen("proc");
141 	while(isspace(*ptr)) ptr++;
142 
143 	proc = get_fs_type("proc");
144 	if(proc == NULL){
145 		mconsole_reply(req, "procfs not registered", 1, 0);
146 		goto out;
147 	}
148 
149 	super = (*proc->get_sb)(proc, 0, NULL, NULL);
150 	put_filesystem(proc);
151 	if(super == NULL){
152 		mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
153 		goto out;
154 	}
155 	up_write(&super->s_umount);
156 
157 	nd.dentry = super->s_root;
158 	nd.mnt = NULL;
159 	nd.flags = O_RDONLY + 1;
160 	nd.last_type = LAST_ROOT;
161 
162 	/* START: it was experienced that the stability problems are closed
163 	 * if commenting out these two calls + the below read cycle. To
164 	 * make UML crash again, it was enough to readd either one.*/
165 	err = link_path_walk(ptr, &nd);
166 	if(err){
167 		mconsole_reply(req, "Failed to look up file", 1, 0);
168 		goto out_kill;
169 	}
170 
171 	file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
172 	if(IS_ERR(file)){
173 		mconsole_reply(req, "Failed to open file", 1, 0);
174 		goto out_kill;
175 	}
176 	/*END*/
177 
178 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
179 	if(buf == NULL){
180 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
181 		goto out_fput;
182 	}
183 
184 	if((file->f_op != NULL) && (file->f_op->read != NULL)){
185 		do {
186 			n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
187 						&file->f_pos);
188 			if(n >= 0){
189 				buf[n] = '\0';
190 				mconsole_reply(req, buf, 0, (n > 0));
191 			}
192 			else {
193 				mconsole_reply(req, "Read of file failed",
194 					       1, 0);
195 				goto out_free;
196 			}
197 		} while(n > 0);
198 	}
199 	else mconsole_reply(req, "", 0, 0);
200 
201  out_free:
202 	kfree(buf);
203  out_fput:
204 	fput(file);
205  out_kill:
206 	deactivate_super(super);
207  out: ;
208 }
209 #endif
210 
211 void mconsole_proc(struct mc_request *req)
212 {
213 	char path[64];
214 	char *buf;
215 	int len;
216 	int fd;
217 	int first_chunk = 1;
218 	char *ptr = req->request.data;
219 
220 	ptr += strlen("proc");
221 	while(isspace(*ptr)) ptr++;
222 	snprintf(path, sizeof(path), "/proc/%s", ptr);
223 
224 	fd = sys_open(path, 0, 0);
225 	if (fd < 0) {
226 		mconsole_reply(req, "Failed to open file", 1, 0);
227 		printk("open %s: %d\n",path,fd);
228 		goto out;
229 	}
230 
231 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
232 	if(buf == NULL){
233 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
234 		goto out_close;
235 	}
236 
237 	for (;;) {
238 		len = sys_read(fd, buf, PAGE_SIZE-1);
239 		if (len < 0) {
240 			mconsole_reply(req, "Read of file failed", 1, 0);
241 			goto out_free;
242 		}
243 		/*Begin the file content on his own line.*/
244 		if (first_chunk) {
245 			mconsole_reply(req, "\n", 0, 1);
246 			first_chunk = 0;
247 		}
248 		if (len == PAGE_SIZE-1) {
249 			buf[len] = '\0';
250 			mconsole_reply(req, buf, 0, 1);
251 		} else {
252 			buf[len] = '\0';
253 			mconsole_reply(req, buf, 0, 0);
254 			break;
255 		}
256 	}
257 
258  out_free:
259 	kfree(buf);
260  out_close:
261 	sys_close(fd);
262  out:
263 	/* nothing */;
264 }
265 
266 #define UML_MCONSOLE_HELPTEXT \
267 "Commands: \n\
268     version - Get kernel version \n\
269     help - Print this message \n\
270     halt - Halt UML \n\
271     reboot - Reboot UML \n\
272     config <dev>=<config> - Add a new device to UML;  \n\
273 	same syntax as command line \n\
274     config <dev> - Query the configuration of a device \n\
275     remove <dev> - Remove a device from UML \n\
276     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
277     cad - invoke the Ctrl-Alt-Del handler \n\
278     stop - pause the UML; it will do nothing until it receives a 'go' \n\
279     go - continue the UML after a 'stop' \n\
280     log <string> - make UML enter <string> into the kernel log\n\
281     proc <file> - returns the contents of the UML's /proc/<file>\n\
282     stack <pid> - returns the stack of the specified pid\n\
283 "
284 
285 void mconsole_help(struct mc_request *req)
286 {
287 	mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
288 }
289 
290 void mconsole_halt(struct mc_request *req)
291 {
292 	mconsole_reply(req, "", 0, 0);
293 	machine_halt();
294 }
295 
296 void mconsole_reboot(struct mc_request *req)
297 {
298 	mconsole_reply(req, "", 0, 0);
299 	machine_restart(NULL);
300 }
301 
302 void mconsole_cad(struct mc_request *req)
303 {
304 	mconsole_reply(req, "", 0, 0);
305 	ctrl_alt_del();
306 }
307 
308 void mconsole_go(struct mc_request *req)
309 {
310 	mconsole_reply(req, "Not stopped", 1, 0);
311 }
312 
313 void mconsole_stop(struct mc_request *req)
314 {
315 	deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
316 	os_set_fd_block(req->originating_fd, 1);
317 	mconsole_reply(req, "stopped", 0, 0);
318 	while (mconsole_get_request(req->originating_fd, req)) {
319 		if (req->cmd->handler == mconsole_go)
320 			break;
321 		if (req->cmd->handler == mconsole_stop) {
322 			mconsole_reply(req, "Already stopped", 1, 0);
323 			continue;
324 		}
325 		if (req->cmd->handler == mconsole_sysrq) {
326 			struct pt_regs *old_regs;
327 			old_regs = set_irq_regs((struct pt_regs *)&req->regs);
328 			mconsole_sysrq(req);
329 			set_irq_regs(old_regs);
330 			continue;
331 		}
332 		(*req->cmd->handler)(req);
333 	}
334 	os_set_fd_block(req->originating_fd, 0);
335 	reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
336 	mconsole_reply(req, "", 0, 0);
337 }
338 
339 static DEFINE_SPINLOCK(mc_devices_lock);
340 static LIST_HEAD(mconsole_devices);
341 
342 void mconsole_register_dev(struct mc_device *new)
343 {
344 	spin_lock(&mc_devices_lock);
345 	BUG_ON(!list_empty(&new->list));
346 	list_add(&new->list, &mconsole_devices);
347 	spin_unlock(&mc_devices_lock);
348 }
349 
350 static struct mc_device *mconsole_find_dev(char *name)
351 {
352 	struct list_head *ele;
353 	struct mc_device *dev;
354 
355 	list_for_each(ele, &mconsole_devices){
356 		dev = list_entry(ele, struct mc_device, list);
357 		if(!strncmp(name, dev->name, strlen(dev->name)))
358 			return(dev);
359 	}
360 	return(NULL);
361 }
362 
363 #define UNPLUGGED_PER_PAGE \
364 	((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
365 
366 struct unplugged_pages {
367 	struct list_head list;
368 	void *pages[UNPLUGGED_PER_PAGE];
369 };
370 
371 static DECLARE_MUTEX(plug_mem_mutex);
372 static unsigned long long unplugged_pages_count = 0;
373 static LIST_HEAD(unplugged_pages);
374 static int unplug_index = UNPLUGGED_PER_PAGE;
375 
376 static int mem_config(char *str, char **error_out)
377 {
378 	unsigned long long diff;
379 	int err = -EINVAL, i, add;
380 	char *ret;
381 
382 	if(str[0] != '='){
383 		*error_out = "Expected '=' after 'mem'";
384 		goto out;
385 	}
386 
387 	str++;
388 	if(str[0] == '-')
389 		add = 0;
390 	else if(str[0] == '+'){
391 		add = 1;
392 	}
393 	else {
394 		*error_out = "Expected increment to start with '-' or '+'";
395 		goto out;
396 	}
397 
398 	str++;
399 	diff = memparse(str, &ret);
400 	if(*ret != '\0'){
401 		*error_out = "Failed to parse memory increment";
402 		goto out;
403 	}
404 
405 	diff /= PAGE_SIZE;
406 
407 	down(&plug_mem_mutex);
408 	for(i = 0; i < diff; i++){
409 		struct unplugged_pages *unplugged;
410 		void *addr;
411 
412 		if(add){
413 			if(list_empty(&unplugged_pages))
414 				break;
415 
416 			unplugged = list_entry(unplugged_pages.next,
417 					       struct unplugged_pages, list);
418 			if(unplug_index > 0)
419 				addr = unplugged->pages[--unplug_index];
420 			else {
421 				list_del(&unplugged->list);
422 				addr = unplugged;
423 				unplug_index = UNPLUGGED_PER_PAGE;
424 			}
425 
426 			free_page((unsigned long) addr);
427 			unplugged_pages_count--;
428 		}
429 		else {
430 			struct page *page;
431 
432 			page = alloc_page(GFP_ATOMIC);
433 			if(page == NULL)
434 				break;
435 
436 			unplugged = page_address(page);
437 			if(unplug_index == UNPLUGGED_PER_PAGE){
438 				list_add(&unplugged->list, &unplugged_pages);
439 				unplug_index = 0;
440 			}
441 			else {
442 				struct list_head *entry = unplugged_pages.next;
443 				addr = unplugged;
444 
445 				unplugged = list_entry(entry,
446 						       struct unplugged_pages,
447 						       list);
448 				err = os_drop_memory(addr, PAGE_SIZE);
449 				if(err){
450 					printk("Failed to release memory - "
451 					       "errno = %d\n", err);
452 					*error_out = "Failed to release memory";
453 					goto out_unlock;
454 				}
455 				unplugged->pages[unplug_index++] = addr;
456 			}
457 
458 			unplugged_pages_count++;
459 		}
460 	}
461 
462 	err = 0;
463 out_unlock:
464 	up(&plug_mem_mutex);
465 out:
466 	return err;
467 }
468 
469 static int mem_get_config(char *name, char *str, int size, char **error_out)
470 {
471 	char buf[sizeof("18446744073709551615")];
472 	int len = 0;
473 
474 	sprintf(buf, "%ld", uml_physmem);
475 	CONFIG_CHUNK(str, size, len, buf, 1);
476 
477 	return len;
478 }
479 
480 static int mem_id(char **str, int *start_out, int *end_out)
481 {
482 	*start_out = 0;
483 	*end_out = 0;
484 
485 	return 0;
486 }
487 
488 static int mem_remove(int n, char **error_out)
489 {
490 	*error_out = "Memory doesn't support the remove operation";
491 	return -EBUSY;
492 }
493 
494 static struct mc_device mem_mc = {
495 	.list		= LIST_HEAD_INIT(mem_mc.list),
496 	.name		= "mem",
497 	.config		= mem_config,
498 	.get_config	= mem_get_config,
499 	.id		= mem_id,
500 	.remove		= mem_remove,
501 };
502 
503 static int mem_mc_init(void)
504 {
505 	if(can_drop_memory())
506 		mconsole_register_dev(&mem_mc);
507 	else printk("Can't release memory to the host - memory hotplug won't "
508 		    "be supported\n");
509 	return 0;
510 }
511 
512 __initcall(mem_mc_init);
513 
514 #define CONFIG_BUF_SIZE 64
515 
516 static void mconsole_get_config(int (*get_config)(char *, char *, int,
517 						  char **),
518 				struct mc_request *req, char *name)
519 {
520 	char default_buf[CONFIG_BUF_SIZE], *error, *buf;
521 	int n, size;
522 
523 	if(get_config == NULL){
524 		mconsole_reply(req, "No get_config routine defined", 1, 0);
525 		return;
526 	}
527 
528 	error = NULL;
529 	size = ARRAY_SIZE(default_buf);
530 	buf = default_buf;
531 
532 	while(1){
533 		n = (*get_config)(name, buf, size, &error);
534 		if(error != NULL){
535 			mconsole_reply(req, error, 1, 0);
536 			goto out;
537 		}
538 
539 		if(n <= size){
540 			mconsole_reply(req, buf, 0, 0);
541 			goto out;
542 		}
543 
544 		if(buf != default_buf)
545 			kfree(buf);
546 
547 		size = n;
548 		buf = kmalloc(size, GFP_KERNEL);
549 		if(buf == NULL){
550 			mconsole_reply(req, "Failed to allocate buffer", 1, 0);
551 			return;
552 		}
553 	}
554  out:
555 	if(buf != default_buf)
556 		kfree(buf);
557 }
558 
559 void mconsole_config(struct mc_request *req)
560 {
561 	struct mc_device *dev;
562 	char *ptr = req->request.data, *name, *error_string = "";
563 	int err;
564 
565 	ptr += strlen("config");
566 	while(isspace(*ptr)) ptr++;
567 	dev = mconsole_find_dev(ptr);
568 	if(dev == NULL){
569 		mconsole_reply(req, "Bad configuration option", 1, 0);
570 		return;
571 	}
572 
573 	name = &ptr[strlen(dev->name)];
574 	ptr = name;
575 	while((*ptr != '=') && (*ptr != '\0'))
576 		ptr++;
577 
578 	if(*ptr == '='){
579 		err = (*dev->config)(name, &error_string);
580 		mconsole_reply(req, error_string, err, 0);
581 	}
582 	else mconsole_get_config(dev->get_config, req, name);
583 }
584 
585 void mconsole_remove(struct mc_request *req)
586 {
587 	struct mc_device *dev;
588 	char *ptr = req->request.data, *err_msg = "";
589 	char error[256];
590 	int err, start, end, n;
591 
592 	ptr += strlen("remove");
593 	while(isspace(*ptr)) ptr++;
594 	dev = mconsole_find_dev(ptr);
595 	if(dev == NULL){
596 		mconsole_reply(req, "Bad remove option", 1, 0);
597 		return;
598 	}
599 
600 	ptr = &ptr[strlen(dev->name)];
601 
602 	err = 1;
603 	n = (*dev->id)(&ptr, &start, &end);
604 	if(n < 0){
605 		err_msg = "Couldn't parse device number";
606 		goto out;
607 	}
608 	else if((n < start) || (n > end)){
609 		sprintf(error, "Invalid device number - must be between "
610 			"%d and %d", start, end);
611 		err_msg = error;
612 		goto out;
613 	}
614 
615 	err_msg = NULL;
616 	err = (*dev->remove)(n, &err_msg);
617 	switch(err){
618 	case 0:
619 		err_msg = "";
620 		break;
621 	case -ENODEV:
622 		if(err_msg == NULL)
623 			err_msg = "Device doesn't exist";
624 		break;
625 	case -EBUSY:
626 		if(err_msg == NULL)
627 			err_msg = "Device is currently open";
628 		break;
629 	default:
630 		break;
631 	}
632 out:
633 	mconsole_reply(req, err_msg, err, 0);
634 }
635 
636 struct mconsole_output {
637 	struct list_head list;
638 	struct mc_request *req;
639 };
640 
641 static DEFINE_SPINLOCK(client_lock);
642 static LIST_HEAD(clients);
643 static char console_buf[MCONSOLE_MAX_DATA];
644 static int console_index = 0;
645 
646 static void console_write(struct console *console, const char *string,
647 			  unsigned len)
648 {
649 	struct list_head *ele;
650 	int n;
651 
652 	if(list_empty(&clients))
653 		return;
654 
655 	while(1){
656 		n = min((size_t) len, ARRAY_SIZE(console_buf) - console_index);
657 		strncpy(&console_buf[console_index], string, n);
658 		console_index += n;
659 		string += n;
660 		len -= n;
661 		if(len == 0)
662 			return;
663 
664 		list_for_each(ele, &clients){
665 			struct mconsole_output *entry;
666 
667 			entry = list_entry(ele, struct mconsole_output, list);
668 			mconsole_reply_len(entry->req, console_buf,
669 					   console_index, 0, 1);
670 		}
671 
672 		console_index = 0;
673 	}
674 }
675 
676 static struct console mc_console = { .name	= "mc",
677 				     .write	= console_write,
678 				     .flags	= CON_ENABLED,
679 				     .index	= -1 };
680 
681 static int mc_add_console(void)
682 {
683 	register_console(&mc_console);
684 	return 0;
685 }
686 
687 late_initcall(mc_add_console);
688 
689 static void with_console(struct mc_request *req, void (*proc)(void *),
690 			 void *arg)
691 {
692 	struct mconsole_output entry;
693 	unsigned long flags;
694 
695 	entry.req = req;
696 	spin_lock_irqsave(&client_lock, flags);
697 	list_add(&entry.list, &clients);
698 	spin_unlock_irqrestore(&client_lock, flags);
699 
700 	(*proc)(arg);
701 
702 	mconsole_reply_len(req, console_buf, console_index, 0, 0);
703 	console_index = 0;
704 
705 	spin_lock_irqsave(&client_lock, flags);
706 	list_del(&entry.list);
707 	spin_unlock_irqrestore(&client_lock, flags);
708 }
709 
710 #ifdef CONFIG_MAGIC_SYSRQ
711 static void sysrq_proc(void *arg)
712 {
713 	char *op = arg;
714 	handle_sysrq(*op, NULL);
715 }
716 
717 void mconsole_sysrq(struct mc_request *req)
718 {
719 	char *ptr = req->request.data;
720 
721 	ptr += strlen("sysrq");
722 	while(isspace(*ptr)) ptr++;
723 
724 	/* With 'b', the system will shut down without a chance to reply,
725 	 * so in this case, we reply first.
726 	 */
727 	if(*ptr == 'b')
728 		mconsole_reply(req, "", 0, 0);
729 
730 	with_console(req, sysrq_proc, ptr);
731 }
732 #else
733 void mconsole_sysrq(struct mc_request *req)
734 {
735 	mconsole_reply(req, "Sysrq not compiled in", 1, 0);
736 }
737 #endif
738 
739 #ifdef CONFIG_MODE_SKAS
740 
741 static void stack_proc(void *arg)
742 {
743 	struct task_struct *from = current, *to = arg;
744 
745 	to->thread.saved_task = from;
746 	switch_to(from, to, from);
747 }
748 
749 /* Mconsole stack trace
750  *  Added by Allan Graves, Jeff Dike
751  *  Dumps a stacks registers to the linux console.
752  *  Usage stack <pid>.
753  */
754 static void do_stack_trace(struct mc_request *req)
755 {
756 	char *ptr = req->request.data;
757 	int pid_requested= -1;
758 	struct task_struct *from = NULL;
759 	struct task_struct *to = NULL;
760 
761 	/* Would be nice:
762 	 * 1) Send showregs output to mconsole.
763 	 * 2) Add a way to stack dump all pids.
764 	 */
765 
766 	ptr += strlen("stack");
767 	while(isspace(*ptr)) ptr++;
768 
769 	/* Should really check for multiple pids or reject bad args here */
770 	/* What do the arguments in mconsole_reply mean? */
771 	if(sscanf(ptr, "%d", &pid_requested) == 0){
772 		mconsole_reply(req, "Please specify a pid", 1, 0);
773 		return;
774 	}
775 
776 	from = current;
777 
778 	to = find_task_by_pid(pid_requested);
779 	if((to == NULL) || (pid_requested == 0)) {
780 		mconsole_reply(req, "Couldn't find that pid", 1, 0);
781 		return;
782 	}
783 	with_console(req, stack_proc, to);
784 }
785 #endif /* CONFIG_MODE_SKAS */
786 
787 void mconsole_stack(struct mc_request *req)
788 {
789 	/* This command doesn't work in TT mode, so let's check and then
790 	 * get out of here
791 	 */
792 	CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
793 				   1, 0),
794 		    do_stack_trace(req));
795 }
796 
797 /* Changed by mconsole_setup, which is __setup, and called before SMP is
798  * active.
799  */
800 static char *notify_socket = NULL;
801 
802 static int mconsole_init(void)
803 {
804 	/* long to avoid size mismatch warnings from gcc */
805 	long sock;
806 	int err;
807 	char file[256];
808 
809 	if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
810 	snprintf(mconsole_socket_name, sizeof(file), "%s", file);
811 
812 	sock = os_create_unix_socket(file, sizeof(file), 1);
813 	if (sock < 0){
814 		printk("Failed to initialize management console\n");
815 		return(1);
816 	}
817 
818 	register_reboot_notifier(&reboot_notifier);
819 
820 	err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
821 			     IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
822 			     "mconsole", (void *)sock);
823 	if (err){
824 		printk("Failed to get IRQ for management console\n");
825 		return(1);
826 	}
827 
828 	if(notify_socket != NULL){
829 		notify_socket = kstrdup(notify_socket, GFP_KERNEL);
830 		if(notify_socket != NULL)
831 			mconsole_notify(notify_socket, MCONSOLE_SOCKET,
832 					mconsole_socket_name,
833 					strlen(mconsole_socket_name) + 1);
834 		else printk(KERN_ERR "mconsole_setup failed to strdup "
835 			    "string\n");
836 	}
837 
838 	printk("mconsole (version %d) initialized on %s\n",
839 	       MCONSOLE_VERSION, mconsole_socket_name);
840 	return(0);
841 }
842 
843 __initcall(mconsole_init);
844 
845 static int write_proc_mconsole(struct file *file, const char __user *buffer,
846 			       unsigned long count, void *data)
847 {
848 	char *buf;
849 
850 	buf = kmalloc(count + 1, GFP_KERNEL);
851 	if(buf == NULL)
852 		return(-ENOMEM);
853 
854 	if(copy_from_user(buf, buffer, count)){
855 		count = -EFAULT;
856 		goto out;
857 	}
858 
859 	buf[count] = '\0';
860 
861 	mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
862  out:
863 	kfree(buf);
864 	return(count);
865 }
866 
867 static int create_proc_mconsole(void)
868 {
869 	struct proc_dir_entry *ent;
870 
871 	if(notify_socket == NULL) return(0);
872 
873 	ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
874 	if(ent == NULL){
875 		printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
876 		return(0);
877 	}
878 
879 	ent->read_proc = NULL;
880 	ent->write_proc = write_proc_mconsole;
881 	return(0);
882 }
883 
884 static DEFINE_SPINLOCK(notify_spinlock);
885 
886 void lock_notify(void)
887 {
888 	spin_lock(&notify_spinlock);
889 }
890 
891 void unlock_notify(void)
892 {
893 	spin_unlock(&notify_spinlock);
894 }
895 
896 __initcall(create_proc_mconsole);
897 
898 #define NOTIFY "=notify:"
899 
900 static int mconsole_setup(char *str)
901 {
902 	if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
903 		str += strlen(NOTIFY);
904 		notify_socket = str;
905 	}
906 	else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
907 	return(1);
908 }
909 
910 __setup("mconsole", mconsole_setup);
911 
912 __uml_help(mconsole_setup,
913 "mconsole=notify:<socket>\n"
914 "    Requests that the mconsole driver send a message to the named Unix\n"
915 "    socket containing the name of the mconsole socket.  This also serves\n"
916 "    to notify outside processes when UML has booted far enough to respond\n"
917 "    to mconsole requests.\n\n"
918 );
919 
920 static int notify_panic(struct notifier_block *self, unsigned long unused1,
921 			void *ptr)
922 {
923 	char *message = ptr;
924 
925 	if(notify_socket == NULL) return(0);
926 
927 	mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
928 			strlen(message) + 1);
929 	return(0);
930 }
931 
932 static struct notifier_block panic_exit_notifier = {
933 	.notifier_call 		= notify_panic,
934 	.next 			= NULL,
935 	.priority 		= 1
936 };
937 
938 static int add_notifier(void)
939 {
940 	atomic_notifier_chain_register(&panic_notifier_list,
941 			&panic_exit_notifier);
942 	return(0);
943 }
944 
945 __initcall(add_notifier);
946 
947 char *mconsole_notify_socket(void)
948 {
949 	return(notify_socket);
950 }
951 
952 EXPORT_SYMBOL(mconsole_notify_socket);
953