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