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