xref: /openbmc/linux/arch/um/drivers/mconsole_kern.c (revision 64c70b1c)
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 "kern_util.h"
29 #include "kern.h"
30 #include "mconsole.h"
31 #include "mconsole_kern.h"
32 #include "irq_user.h"
33 #include "init.h"
34 #include "os.h"
35 #include "irq_kern.h"
36 #include "choose-mode.h"
37 
38 static int do_unlink_socket(struct notifier_block *notifier,
39 			    unsigned long what, void *data)
40 {
41 	return(mconsole_unlink_socket());
42 }
43 
44 
45 static struct notifier_block reboot_notifier = {
46 	.notifier_call		= do_unlink_socket,
47 	.priority		= 0,
48 };
49 
50 /* Safe without explicit locking for now.  Tasklets provide their own
51  * locking, and the interrupt handler is safe because it can't interrupt
52  * itself and it can only happen on CPU 0.
53  */
54 
55 static LIST_HEAD(mc_requests);
56 
57 static void mc_work_proc(struct work_struct *unused)
58 {
59 	struct mconsole_entry *req;
60 	unsigned long flags;
61 
62 	while(!list_empty(&mc_requests)){
63 		local_irq_save(flags);
64 		req = list_entry(mc_requests.next, struct mconsole_entry,
65 				 list);
66 		list_del(&req->list);
67 		local_irq_restore(flags);
68 		req->request.cmd->handler(&req->request);
69 		kfree(req);
70 	}
71 }
72 
73 static DECLARE_WORK(mconsole_work, mc_work_proc);
74 
75 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
76 {
77 	/* long to avoid size mismatch warnings from gcc */
78 	long fd;
79 	struct mconsole_entry *new;
80 	static struct mc_request req;	/* that's OK */
81 
82 	fd = (long) dev_id;
83 	while (mconsole_get_request(fd, &req)){
84 		if(req.cmd->context == MCONSOLE_INTR)
85 			(*req.cmd->handler)(&req);
86 		else {
87 			new = kmalloc(sizeof(*new), GFP_NOWAIT);
88 			if(new == NULL)
89 				mconsole_reply(&req, "Out of memory", 1, 0);
90 			else {
91 				new->request = req;
92 				new->request.regs = get_irq_regs()->regs;
93 				list_add(&new->list, &mc_requests);
94 			}
95 		}
96 	}
97 	if(!list_empty(&mc_requests))
98 		schedule_work(&mconsole_work);
99 	reactivate_fd(fd, MCONSOLE_IRQ);
100 	return(IRQ_HANDLED);
101 }
102 
103 void mconsole_version(struct mc_request *req)
104 {
105 	char version[256];
106 
107 	sprintf(version, "%s %s %s %s %s", utsname()->sysname,
108 		utsname()->nodename, utsname()->release,
109 		utsname()->version, utsname()->machine);
110 	mconsole_reply(req, version, 0, 0);
111 }
112 
113 void mconsole_log(struct mc_request *req)
114 {
115 	int len;
116 	char *ptr = req->request.data;
117 
118 	ptr += strlen("log ");
119 
120 	len = req->len - (ptr - req->request.data);
121 	printk("%.*s", len, ptr);
122 	mconsole_reply(req, "", 0, 0);
123 }
124 
125 /* This is a more convoluted version of mconsole_proc, which has some stability
126  * problems; however, we need it fixed, because it is expected that UML users
127  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
128  * show the real procfs content, not the ones from hppfs.*/
129 #if 0
130 void mconsole_proc(struct mc_request *req)
131 {
132 	struct nameidata nd;
133 	struct file_system_type *proc;
134 	struct super_block *super;
135 	struct file *file;
136 	int n, err;
137 	char *ptr = req->request.data, *buf;
138 
139 	ptr += strlen("proc");
140 	while(isspace(*ptr)) ptr++;
141 
142 	proc = get_fs_type("proc");
143 	if(proc == NULL){
144 		mconsole_reply(req, "procfs not registered", 1, 0);
145 		goto out;
146 	}
147 
148 	super = (*proc->get_sb)(proc, 0, NULL, NULL);
149 	put_filesystem(proc);
150 	if(super == NULL){
151 		mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
152 		goto out;
153 	}
154 	up_write(&super->s_umount);
155 
156 	nd.dentry = super->s_root;
157 	nd.mnt = NULL;
158 	nd.flags = O_RDONLY + 1;
159 	nd.last_type = LAST_ROOT;
160 
161 	/* START: it was experienced that the stability problems are closed
162 	 * if commenting out these two calls + the below read cycle. To
163 	 * make UML crash again, it was enough to readd either one.*/
164 	err = link_path_walk(ptr, &nd);
165 	if(err){
166 		mconsole_reply(req, "Failed to look up file", 1, 0);
167 		goto out_kill;
168 	}
169 
170 	file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
171 	if(IS_ERR(file)){
172 		mconsole_reply(req, "Failed to open file", 1, 0);
173 		goto out_kill;
174 	}
175 	/*END*/
176 
177 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
178 	if(buf == NULL){
179 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
180 		goto out_fput;
181 	}
182 
183 	if((file->f_op != NULL) && (file->f_op->read != NULL)){
184 		do {
185 			n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
186 						&file->f_pos);
187 			if(n >= 0){
188 				buf[n] = '\0';
189 				mconsole_reply(req, buf, 0, (n > 0));
190 			}
191 			else {
192 				mconsole_reply(req, "Read of file failed",
193 					       1, 0);
194 				goto out_free;
195 			}
196 		} while(n > 0);
197 	}
198 	else mconsole_reply(req, "", 0, 0);
199 
200  out_free:
201 	kfree(buf);
202  out_fput:
203 	fput(file);
204  out_kill:
205 	deactivate_super(super);
206  out: ;
207 }
208 #endif
209 
210 void mconsole_proc(struct mc_request *req)
211 {
212 	char path[64];
213 	char *buf;
214 	int len;
215 	int fd;
216 	int first_chunk = 1;
217 	char *ptr = req->request.data;
218 
219 	ptr += strlen("proc");
220 	while(isspace(*ptr)) ptr++;
221 	snprintf(path, sizeof(path), "/proc/%s", ptr);
222 
223 	fd = sys_open(path, 0, 0);
224 	if (fd < 0) {
225 		mconsole_reply(req, "Failed to open file", 1, 0);
226 		printk("open %s: %d\n",path,fd);
227 		goto out;
228 	}
229 
230 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
231 	if(buf == NULL){
232 		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
233 		goto out_close;
234 	}
235 
236 	for (;;) {
237 		len = sys_read(fd, buf, PAGE_SIZE-1);
238 		if (len < 0) {
239 			mconsole_reply(req, "Read of file failed", 1, 0);
240 			goto out_free;
241 		}
242 		/*Begin the file content on his own line.*/
243 		if (first_chunk) {
244 			mconsole_reply(req, "\n", 0, 1);
245 			first_chunk = 0;
246 		}
247 		if (len == PAGE_SIZE-1) {
248 			buf[len] = '\0';
249 			mconsole_reply(req, buf, 0, 1);
250 		} else {
251 			buf[len] = '\0';
252 			mconsole_reply(req, buf, 0, 0);
253 			break;
254 		}
255 	}
256 
257  out_free:
258 	kfree(buf);
259  out_close:
260 	sys_close(fd);
261  out:
262 	/* nothing */;
263 }
264 
265 #define UML_MCONSOLE_HELPTEXT \
266 "Commands: \n\
267     version - Get kernel version \n\
268     help - Print this message \n\
269     halt - Halt UML \n\
270     reboot - Reboot UML \n\
271     config <dev>=<config> - Add a new device to UML;  \n\
272 	same syntax as command line \n\
273     config <dev> - Query the configuration of a device \n\
274     remove <dev> - Remove a device from UML \n\
275     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
276     cad - invoke the Ctrl-Alt-Del handler \n\
277     stop - pause the UML; it will do nothing until it receives a 'go' \n\
278     go - continue the UML after a 'stop' \n\
279     log <string> - make UML enter <string> into the kernel log\n\
280     proc <file> - returns the contents of the UML's /proc/<file>\n\
281     stack <pid> - returns the stack of the specified pid\n\
282 "
283 
284 void mconsole_help(struct mc_request *req)
285 {
286 	mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
287 }
288 
289 void mconsole_halt(struct mc_request *req)
290 {
291 	mconsole_reply(req, "", 0, 0);
292 	machine_halt();
293 }
294 
295 void mconsole_reboot(struct mc_request *req)
296 {
297 	mconsole_reply(req, "", 0, 0);
298 	machine_restart(NULL);
299 }
300 
301 void mconsole_cad(struct mc_request *req)
302 {
303 	mconsole_reply(req, "", 0, 0);
304 	ctrl_alt_del();
305 }
306 
307 void mconsole_go(struct mc_request *req)
308 {
309 	mconsole_reply(req, "Not stopped", 1, 0);
310 }
311 
312 void mconsole_stop(struct mc_request *req)
313 {
314 	deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
315 	os_set_fd_block(req->originating_fd, 1);
316 	mconsole_reply(req, "stopped", 0, 0);
317 	while (mconsole_get_request(req->originating_fd, req)) {
318 		if (req->cmd->handler == mconsole_go)
319 			break;
320 		if (req->cmd->handler == mconsole_stop) {
321 			mconsole_reply(req, "Already stopped", 1, 0);
322 			continue;
323 		}
324 		if (req->cmd->handler == mconsole_sysrq) {
325 			struct pt_regs *old_regs;
326 			old_regs = set_irq_regs((struct pt_regs *)&req->regs);
327 			mconsole_sysrq(req);
328 			set_irq_regs(old_regs);
329 			continue;
330 		}
331 		(*req->cmd->handler)(req);
332 	}
333 	os_set_fd_block(req->originating_fd, 0);
334 	reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
335 	mconsole_reply(req, "", 0, 0);
336 }
337 
338 static DEFINE_SPINLOCK(mc_devices_lock);
339 static LIST_HEAD(mconsole_devices);
340 
341 void mconsole_register_dev(struct mc_device *new)
342 {
343 	spin_lock(&mc_devices_lock);
344 	BUG_ON(!list_empty(&new->list));
345 	list_add(&new->list, &mconsole_devices);
346 	spin_unlock(&mc_devices_lock);
347 }
348 
349 static struct mc_device *mconsole_find_dev(char *name)
350 {
351 	struct list_head *ele;
352 	struct mc_device *dev;
353 
354 	list_for_each(ele, &mconsole_devices){
355 		dev = list_entry(ele, struct mc_device, list);
356 		if(!strncmp(name, dev->name, strlen(dev->name)))
357 			return(dev);
358 	}
359 	return(NULL);
360 }
361 
362 #define UNPLUGGED_PER_PAGE \
363 	((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
364 
365 struct unplugged_pages {
366 	struct list_head list;
367 	void *pages[UNPLUGGED_PER_PAGE];
368 };
369 
370 static DECLARE_MUTEX(plug_mem_mutex);
371 static unsigned long long unplugged_pages_count = 0;
372 static LIST_HEAD(unplugged_pages);
373 static int unplug_index = UNPLUGGED_PER_PAGE;
374 
375 static int mem_config(char *str, char **error_out)
376 {
377 	unsigned long long diff;
378 	int err = -EINVAL, i, add;
379 	char *ret;
380 
381 	if(str[0] != '='){
382 		*error_out = "Expected '=' after 'mem'";
383 		goto out;
384 	}
385 
386 	str++;
387 	if(str[0] == '-')
388 		add = 0;
389 	else if(str[0] == '+'){
390 		add = 1;
391 	}
392 	else {
393 		*error_out = "Expected increment to start with '-' or '+'";
394 		goto out;
395 	}
396 
397 	str++;
398 	diff = memparse(str, &ret);
399 	if(*ret != '\0'){
400 		*error_out = "Failed to parse memory increment";
401 		goto out;
402 	}
403 
404 	diff /= PAGE_SIZE;
405 
406 	down(&plug_mem_mutex);
407 	for(i = 0; i < diff; i++){
408 		struct unplugged_pages *unplugged;
409 		void *addr;
410 
411 		if(add){
412 			if(list_empty(&unplugged_pages))
413 				break;
414 
415 			unplugged = list_entry(unplugged_pages.next,
416 					       struct unplugged_pages, list);
417 			if(unplug_index > 0)
418 				addr = unplugged->pages[--unplug_index];
419 			else {
420 				list_del(&unplugged->list);
421 				addr = unplugged;
422 				unplug_index = UNPLUGGED_PER_PAGE;
423 			}
424 
425 			free_page((unsigned long) addr);
426 			unplugged_pages_count--;
427 		}
428 		else {
429 			struct page *page;
430 
431 			page = alloc_page(GFP_ATOMIC);
432 			if(page == NULL)
433 				break;
434 
435 			unplugged = page_address(page);
436 			if(unplug_index == UNPLUGGED_PER_PAGE){
437 				list_add(&unplugged->list, &unplugged_pages);
438 				unplug_index = 0;
439 			}
440 			else {
441 				struct list_head *entry = unplugged_pages.next;
442 				addr = unplugged;
443 
444 				unplugged = list_entry(entry,
445 						       struct unplugged_pages,
446 						       list);
447 				err = os_drop_memory(addr, PAGE_SIZE);
448 				if(err){
449 					printk("Failed to release memory - "
450 					       "errno = %d\n", err);
451 					*error_out = "Failed to release memory";
452 					goto out_unlock;
453 				}
454 				unplugged->pages[unplug_index++] = addr;
455 			}
456 
457 			unplugged_pages_count++;
458 		}
459 	}
460 
461 	err = 0;
462 out_unlock:
463 	up(&plug_mem_mutex);
464 out:
465 	return err;
466 }
467 
468 static int mem_get_config(char *name, char *str, int size, char **error_out)
469 {
470 	char buf[sizeof("18446744073709551615")];
471 	int len = 0;
472 
473 	sprintf(buf, "%ld", uml_physmem);
474 	CONFIG_CHUNK(str, size, len, buf, 1);
475 
476 	return len;
477 }
478 
479 static int mem_id(char **str, int *start_out, int *end_out)
480 {
481 	*start_out = 0;
482 	*end_out = 0;
483 
484 	return 0;
485 }
486 
487 static int mem_remove(int n, char **error_out)
488 {
489 	*error_out = "Memory doesn't support the remove operation";
490 	return -EBUSY;
491 }
492 
493 static struct mc_device mem_mc = {
494 	.list		= LIST_HEAD_INIT(mem_mc.list),
495 	.name		= "mem",
496 	.config		= mem_config,
497 	.get_config	= mem_get_config,
498 	.id		= mem_id,
499 	.remove		= mem_remove,
500 };
501 
502 static int mem_mc_init(void)
503 {
504 	if(can_drop_memory())
505 		mconsole_register_dev(&mem_mc);
506 	else printk("Can't release memory to the host - memory hotplug won't "
507 		    "be supported\n");
508 	return 0;
509 }
510 
511 __initcall(mem_mc_init);
512 
513 #define CONFIG_BUF_SIZE 64
514 
515 static void mconsole_get_config(int (*get_config)(char *, char *, int,
516 						  char **),
517 				struct mc_request *req, char *name)
518 {
519 	char default_buf[CONFIG_BUF_SIZE], *error, *buf;
520 	int n, size;
521 
522 	if(get_config == NULL){
523 		mconsole_reply(req, "No get_config routine defined", 1, 0);
524 		return;
525 	}
526 
527 	error = NULL;
528 	size = ARRAY_SIZE(default_buf);
529 	buf = default_buf;
530 
531 	while(1){
532 		n = (*get_config)(name, buf, size, &error);
533 		if(error != NULL){
534 			mconsole_reply(req, error, 1, 0);
535 			goto out;
536 		}
537 
538 		if(n <= size){
539 			mconsole_reply(req, buf, 0, 0);
540 			goto out;
541 		}
542 
543 		if(buf != default_buf)
544 			kfree(buf);
545 
546 		size = n;
547 		buf = kmalloc(size, GFP_KERNEL);
548 		if(buf == NULL){
549 			mconsole_reply(req, "Failed to allocate buffer", 1, 0);
550 			return;
551 		}
552 	}
553  out:
554 	if(buf != default_buf)
555 		kfree(buf);
556 }
557 
558 void mconsole_config(struct mc_request *req)
559 {
560 	struct mc_device *dev;
561 	char *ptr = req->request.data, *name, *error_string = "";
562 	int err;
563 
564 	ptr += strlen("config");
565 	while(isspace(*ptr)) ptr++;
566 	dev = mconsole_find_dev(ptr);
567 	if(dev == NULL){
568 		mconsole_reply(req, "Bad configuration option", 1, 0);
569 		return;
570 	}
571 
572 	name = &ptr[strlen(dev->name)];
573 	ptr = name;
574 	while((*ptr != '=') && (*ptr != '\0'))
575 		ptr++;
576 
577 	if(*ptr == '='){
578 		err = (*dev->config)(name, &error_string);
579 		mconsole_reply(req, error_string, err, 0);
580 	}
581 	else mconsole_get_config(dev->get_config, req, name);
582 }
583 
584 void mconsole_remove(struct mc_request *req)
585 {
586 	struct mc_device *dev;
587 	char *ptr = req->request.data, *err_msg = "";
588 	char error[256];
589 	int err, start, end, n;
590 
591 	ptr += strlen("remove");
592 	while(isspace(*ptr)) ptr++;
593 	dev = mconsole_find_dev(ptr);
594 	if(dev == NULL){
595 		mconsole_reply(req, "Bad remove option", 1, 0);
596 		return;
597 	}
598 
599 	ptr = &ptr[strlen(dev->name)];
600 
601 	err = 1;
602 	n = (*dev->id)(&ptr, &start, &end);
603 	if(n < 0){
604 		err_msg = "Couldn't parse device number";
605 		goto out;
606 	}
607 	else if((n < start) || (n > end)){
608 		sprintf(error, "Invalid device number - must be between "
609 			"%d and %d", start, end);
610 		err_msg = error;
611 		goto out;
612 	}
613 
614 	err_msg = NULL;
615 	err = (*dev->remove)(n, &err_msg);
616 	switch(err){
617 	case 0:
618 		err_msg = "";
619 		break;
620 	case -ENODEV:
621 		if(err_msg == NULL)
622 			err_msg = "Device doesn't exist";
623 		break;
624 	case -EBUSY:
625 		if(err_msg == NULL)
626 			err_msg = "Device is currently open";
627 		break;
628 	default:
629 		break;
630 	}
631 out:
632 	mconsole_reply(req, err_msg, err, 0);
633 }
634 
635 struct mconsole_output {
636 	struct list_head list;
637 	struct mc_request *req;
638 };
639 
640 static DEFINE_SPINLOCK(client_lock);
641 static LIST_HEAD(clients);
642 static char console_buf[MCONSOLE_MAX_DATA];
643 static int console_index = 0;
644 
645 static void console_write(struct console *console, const char *string,
646 			  unsigned len)
647 {
648 	struct list_head *ele;
649 	int n;
650 
651 	if(list_empty(&clients))
652 		return;
653 
654 	while(1){
655 		n = min((size_t) len, ARRAY_SIZE(console_buf) - console_index);
656 		strncpy(&console_buf[console_index], string, n);
657 		console_index += n;
658 		string += n;
659 		len -= n;
660 		if(len == 0)
661 			return;
662 
663 		list_for_each(ele, &clients){
664 			struct mconsole_output *entry;
665 
666 			entry = list_entry(ele, struct mconsole_output, list);
667 			mconsole_reply_len(entry->req, console_buf,
668 					   console_index, 0, 1);
669 		}
670 
671 		console_index = 0;
672 	}
673 }
674 
675 static struct console mc_console = { .name	= "mc",
676 				     .write	= console_write,
677 				     .flags	= CON_ENABLED,
678 				     .index	= -1 };
679 
680 static int mc_add_console(void)
681 {
682 	register_console(&mc_console);
683 	return 0;
684 }
685 
686 late_initcall(mc_add_console);
687 
688 static void with_console(struct mc_request *req, void (*proc)(void *),
689 			 void *arg)
690 {
691 	struct mconsole_output entry;
692 	unsigned long flags;
693 
694 	entry.req = req;
695 	spin_lock_irqsave(&client_lock, flags);
696 	list_add(&entry.list, &clients);
697 	spin_unlock_irqrestore(&client_lock, flags);
698 
699 	(*proc)(arg);
700 
701 	mconsole_reply_len(req, console_buf, console_index, 0, 0);
702 	console_index = 0;
703 
704 	spin_lock_irqsave(&client_lock, flags);
705 	list_del(&entry.list);
706 	spin_unlock_irqrestore(&client_lock, flags);
707 }
708 
709 #ifdef CONFIG_MAGIC_SYSRQ
710 static void sysrq_proc(void *arg)
711 {
712 	char *op = arg;
713 	handle_sysrq(*op, NULL);
714 }
715 
716 void mconsole_sysrq(struct mc_request *req)
717 {
718 	char *ptr = req->request.data;
719 
720 	ptr += strlen("sysrq");
721 	while(isspace(*ptr)) ptr++;
722 
723 	/* With 'b', the system will shut down without a chance to reply,
724 	 * so in this case, we reply first.
725 	 */
726 	if(*ptr == 'b')
727 		mconsole_reply(req, "", 0, 0);
728 
729 	with_console(req, sysrq_proc, ptr);
730 }
731 #else
732 void mconsole_sysrq(struct mc_request *req)
733 {
734 	mconsole_reply(req, "Sysrq not compiled in", 1, 0);
735 }
736 #endif
737 
738 #ifdef CONFIG_MODE_SKAS
739 
740 static void stack_proc(void *arg)
741 {
742 	struct task_struct *from = current, *to = arg;
743 
744 	to->thread.saved_task = from;
745 	switch_to(from, to, from);
746 }
747 
748 /* Mconsole stack trace
749  *  Added by Allan Graves, Jeff Dike
750  *  Dumps a stacks registers to the linux console.
751  *  Usage stack <pid>.
752  */
753 static void do_stack_trace(struct mc_request *req)
754 {
755 	char *ptr = req->request.data;
756 	int pid_requested= -1;
757 	struct task_struct *from = NULL;
758 	struct task_struct *to = NULL;
759 
760 	/* Would be nice:
761 	 * 1) Send showregs output to mconsole.
762 	 * 2) Add a way to stack dump all pids.
763 	 */
764 
765 	ptr += strlen("stack");
766 	while(isspace(*ptr)) ptr++;
767 
768 	/* Should really check for multiple pids or reject bad args here */
769 	/* What do the arguments in mconsole_reply mean? */
770 	if(sscanf(ptr, "%d", &pid_requested) == 0){
771 		mconsole_reply(req, "Please specify a pid", 1, 0);
772 		return;
773 	}
774 
775 	from = current;
776 
777 	to = find_task_by_pid(pid_requested);
778 	if((to == NULL) || (pid_requested == 0)) {
779 		mconsole_reply(req, "Couldn't find that pid", 1, 0);
780 		return;
781 	}
782 	with_console(req, stack_proc, to);
783 }
784 #endif /* CONFIG_MODE_SKAS */
785 
786 void mconsole_stack(struct mc_request *req)
787 {
788 	/* This command doesn't work in TT mode, so let's check and then
789 	 * get out of here
790 	 */
791 	CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
792 				   1, 0),
793 		    do_stack_trace(req));
794 }
795 
796 /* Changed by mconsole_setup, which is __setup, and called before SMP is
797  * active.
798  */
799 static char *notify_socket = NULL;
800 
801 static int mconsole_init(void)
802 {
803 	/* long to avoid size mismatch warnings from gcc */
804 	long sock;
805 	int err;
806 	char file[256];
807 
808 	if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
809 	snprintf(mconsole_socket_name, sizeof(file), "%s", file);
810 
811 	sock = os_create_unix_socket(file, sizeof(file), 1);
812 	if (sock < 0){
813 		printk("Failed to initialize management console\n");
814 		return(1);
815 	}
816 
817 	register_reboot_notifier(&reboot_notifier);
818 
819 	err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
820 			     IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
821 			     "mconsole", (void *)sock);
822 	if (err){
823 		printk("Failed to get IRQ for management console\n");
824 		return(1);
825 	}
826 
827 	if(notify_socket != NULL){
828 		notify_socket = kstrdup(notify_socket, GFP_KERNEL);
829 		if(notify_socket != NULL)
830 			mconsole_notify(notify_socket, MCONSOLE_SOCKET,
831 					mconsole_socket_name,
832 					strlen(mconsole_socket_name) + 1);
833 		else printk(KERN_ERR "mconsole_setup failed to strdup "
834 			    "string\n");
835 	}
836 
837 	printk("mconsole (version %d) initialized on %s\n",
838 	       MCONSOLE_VERSION, mconsole_socket_name);
839 	return(0);
840 }
841 
842 __initcall(mconsole_init);
843 
844 static int write_proc_mconsole(struct file *file, const char __user *buffer,
845 			       unsigned long count, void *data)
846 {
847 	char *buf;
848 
849 	buf = kmalloc(count + 1, GFP_KERNEL);
850 	if(buf == NULL)
851 		return(-ENOMEM);
852 
853 	if(copy_from_user(buf, buffer, count)){
854 		count = -EFAULT;
855 		goto out;
856 	}
857 
858 	buf[count] = '\0';
859 
860 	mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
861  out:
862 	kfree(buf);
863 	return(count);
864 }
865 
866 static int create_proc_mconsole(void)
867 {
868 	struct proc_dir_entry *ent;
869 
870 	if(notify_socket == NULL) return(0);
871 
872 	ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
873 	if(ent == NULL){
874 		printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
875 		return(0);
876 	}
877 
878 	ent->read_proc = NULL;
879 	ent->write_proc = write_proc_mconsole;
880 	return(0);
881 }
882 
883 static DEFINE_SPINLOCK(notify_spinlock);
884 
885 void lock_notify(void)
886 {
887 	spin_lock(&notify_spinlock);
888 }
889 
890 void unlock_notify(void)
891 {
892 	spin_unlock(&notify_spinlock);
893 }
894 
895 __initcall(create_proc_mconsole);
896 
897 #define NOTIFY "=notify:"
898 
899 static int mconsole_setup(char *str)
900 {
901 	if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
902 		str += strlen(NOTIFY);
903 		notify_socket = str;
904 	}
905 	else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
906 	return(1);
907 }
908 
909 __setup("mconsole", mconsole_setup);
910 
911 __uml_help(mconsole_setup,
912 "mconsole=notify:<socket>\n"
913 "    Requests that the mconsole driver send a message to the named Unix\n"
914 "    socket containing the name of the mconsole socket.  This also serves\n"
915 "    to notify outside processes when UML has booted far enough to respond\n"
916 "    to mconsole requests.\n\n"
917 );
918 
919 static int notify_panic(struct notifier_block *self, unsigned long unused1,
920 			void *ptr)
921 {
922 	char *message = ptr;
923 
924 	if(notify_socket == NULL) return(0);
925 
926 	mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
927 			strlen(message) + 1);
928 	return(0);
929 }
930 
931 static struct notifier_block panic_exit_notifier = {
932 	.notifier_call 		= notify_panic,
933 	.next 			= NULL,
934 	.priority 		= 1
935 };
936 
937 static int add_notifier(void)
938 {
939 	atomic_notifier_chain_register(&panic_notifier_list,
940 			&panic_exit_notifier);
941 	return(0);
942 }
943 
944 __initcall(add_notifier);
945 
946 char *mconsole_notify_socket(void)
947 {
948 	return(notify_socket);
949 }
950 
951 EXPORT_SYMBOL(mconsole_notify_socket);
952