summaryrefslogtreecommitdiff
path: root/arch/um/drivers/mconsole_kern.c
blob: 12c95368124afa58940bba1326ecc4cc1352c4c7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
/*
 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
 * Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
 * Licensed under the GPL
 */

#include "linux/kernel.h"
#include "linux/slab.h"
#include "linux/init.h"
#include "linux/notifier.h"
#include "linux/reboot.h"
#include "linux/utsname.h"
#include "linux/ctype.h"
#include "linux/interrupt.h"
#include "linux/sysrq.h"
#include "linux/workqueue.h"
#include "linux/module.h"
#include "linux/file.h"
#include "linux/fs.h"
#include "linux/namei.h"
#include "linux/proc_fs.h"
#include "linux/syscalls.h"
#include "asm/irq.h"
#include "asm/uaccess.h"
#include "user_util.h"
#include "kern_util.h"
#include "kern.h"
#include "mconsole.h"
#include "mconsole_kern.h"
#include "irq_user.h"
#include "init.h"
#include "os.h"
#include "umid.h"
#include "irq_kern.h"
#include "choose-mode.h"

static int do_unlink_socket(struct notifier_block *notifier, 
			    unsigned long what, void *data)
{
	return(mconsole_unlink_socket());
}


static struct notifier_block reboot_notifier = {
	.notifier_call		= do_unlink_socket,
	.priority		= 0,
};

/* Safe without explicit locking for now.  Tasklets provide their own 
 * locking, and the interrupt handler is safe because it can't interrupt
 * itself and it can only happen on CPU 0.
 */

LIST_HEAD(mc_requests);

static void mc_work_proc(void *unused)
{
	struct mconsole_entry *req;
	unsigned long flags;

	while(!list_empty(&mc_requests)){
		local_save_flags(flags);
		req = list_entry(mc_requests.next, struct mconsole_entry, 
				 list);
		list_del(&req->list);
		local_irq_restore(flags);
		req->request.cmd->handler(&req->request);
		kfree(req);
	}
}

DECLARE_WORK(mconsole_work, mc_work_proc, NULL);

static irqreturn_t mconsole_interrupt(int irq, void *dev_id,
				      struct pt_regs *regs)
{
	/* long to avoid size mismatch warnings from gcc */
	long fd;
	struct mconsole_entry *new;
	struct mc_request req;

	fd = (long) dev_id;
	while (mconsole_get_request(fd, &req)){
		if(req.cmd->context == MCONSOLE_INTR)
			(*req.cmd->handler)(&req);
		else {
			new = kmalloc(sizeof(*new), GFP_ATOMIC);
			if(new == NULL)
				mconsole_reply(&req, "Out of memory", 1, 0);
			else {
				new->request = req;
				list_add(&new->list, &mc_requests);
			}
		}
	}
	if(!list_empty(&mc_requests))
		schedule_work(&mconsole_work);
	reactivate_fd(fd, MCONSOLE_IRQ);
	return(IRQ_HANDLED);
}

void mconsole_version(struct mc_request *req)
{
	char version[256];

	sprintf(version, "%s %s %s %s %s", system_utsname.sysname, 
		system_utsname.nodename, system_utsname.release, 
		system_utsname.version, system_utsname.machine);
	mconsole_reply(req, version, 0, 0);
}

void mconsole_log(struct mc_request *req)
{
	int len;
	char *ptr = req->request.data;

	ptr += strlen("log ");

	len = req->len - (ptr - req->request.data);
	printk("%.*s", len, ptr);
	mconsole_reply(req, "", 0, 0);
}

/* This is a more convoluted version of mconsole_proc, which has some stability
 * problems; however, we need it fixed, because it is expected that UML users
 * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
 * show the real procfs content, not the ones from hppfs.*/
#if 0
void mconsole_proc(struct mc_request *req)
{
	struct nameidata nd;
	struct file_system_type *proc;
	struct super_block *super;
	struct file *file;
	int n, err;
	char *ptr = req->request.data, *buf;

	ptr += strlen("proc");
	while(isspace(*ptr)) ptr++;

	proc = get_fs_type("proc");
	if(proc == NULL){
		mconsole_reply(req, "procfs not registered", 1, 0);
		goto out;
	}

	super = (*proc->get_sb)(proc, 0, NULL, NULL);
	put_filesystem(proc);
	if(super == NULL){
		mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
		goto out;
	}
	up_write(&super->s_umount);

	nd.dentry = super->s_root;
	nd.mnt = NULL;
	nd.flags = O_RDONLY + 1;
	nd.last_type = LAST_ROOT;

	/* START: it was experienced that the stability problems are closed
	 * if commenting out these two calls + the below read cycle. To
	 * make UML crash again, it was enough to readd either one.*/
	err = link_path_walk(ptr, &nd);
	if(err){
		mconsole_reply(req, "Failed to look up file", 1, 0);
		goto out_kill;
	}

	file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
	if(IS_ERR(file)){
		mconsole_reply(req, "Failed to open file", 1, 0);
		goto out_kill;
	}
	/*END*/

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if(buf == NULL){
		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
		goto out_fput;
	}

	if((file->f_op != NULL) && (file->f_op->read != NULL)){
		do {
			n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
						&file->f_pos);
			if(n >= 0){
				buf[n] = '\0';
				mconsole_reply(req, buf, 0, (n > 0));
			}
			else {
				mconsole_reply(req, "Read of file failed",
					       1, 0);
				goto out_free;
			}
		} while(n > 0);
	}
	else mconsole_reply(req, "", 0, 0);

 out_free:
	kfree(buf);
 out_fput:
	fput(file);
 out_kill:
	deactivate_super(super);
 out: ;
}
#endif

void mconsole_proc(struct mc_request *req)
{
	char path[64];
	char *buf;
	int len;
	int fd;
	int first_chunk = 1;
	char *ptr = req->request.data;

	ptr += strlen("proc");
	while(isspace(*ptr)) ptr++;
	snprintf(path, sizeof(path), "/proc/%s", ptr);

	fd = sys_open(path, 0, 0);
	if (fd < 0) {
		mconsole_reply(req, "Failed to open file", 1, 0);
		printk("open %s: %d\n",path,fd);
		goto out;
	}

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if(buf == NULL){
		mconsole_reply(req, "Failed to allocate buffer", 1, 0);
		goto out_close;
	}

	for (;;) {
		len = sys_read(fd, buf, PAGE_SIZE-1);
		if (len < 0) {
			mconsole_reply(req, "Read of file failed", 1, 0);
			goto out_free;
		}
		/*Begin the file content on his own line.*/
		if (first_chunk) {
			mconsole_reply(req, "\n", 0, 1);
			first_chunk = 0;
		}
		if (len == PAGE_SIZE-1) {
			buf[len] = '\0';
			mconsole_reply(req, buf, 0, 1);
		} else {
			buf[len] = '\0';
			mconsole_reply(req, buf, 0, 0);
			break;
		}
	}

 out_free:
	kfree(buf);
 out_close:
	sys_close(fd);
 out:
	/* nothing */;
}

#define UML_MCONSOLE_HELPTEXT \
"Commands: \n\
    version - Get kernel version \n\
    help - Print this message \n\
    halt - Halt UML \n\
    reboot - Reboot UML \n\
    config <dev>=<config> - Add a new device to UML;  \n\
	same syntax as command line \n\
    config <dev> - Query the configuration of a device \n\
    remove <dev> - Remove a device from UML \n\
    sysrq <letter> - Performs the SysRq action controlled by the letter \n\
    cad - invoke the Ctl-Alt-Del handler \n\
    stop - pause the UML; it will do nothing until it receives a 'go' \n\
    go - continue the UML after a 'stop' \n\
    log <string> - make UML enter <string> into the kernel log\n\
    proc <file> - returns the contents of the UML's /proc/<file>\n\
    stack <pid> - returns the stack of the specified pid\n\
"

void mconsole_help(struct mc_request *req)
{
	mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
}

void mconsole_halt(struct mc_request *req)
{
	mconsole_reply(req, "", 0, 0);
	machine_halt();
}

void mconsole_reboot(struct mc_request *req)
{
	mconsole_reply(req, "", 0, 0);
	machine_restart(NULL);
}

extern void ctrl_alt_del(void);

void mconsole_cad(struct mc_request *req)
{
	mconsole_reply(req, "", 0, 0);
	ctrl_alt_del();
}

void mconsole_go(struct mc_request *req)
{
	mconsole_reply(req, "Not stopped", 1, 0);
}

void mconsole_stop(struct mc_request *req)
{
	deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
	os_set_fd_block(req->originating_fd, 1);
	mconsole_reply(req, "", 0, 0);
	while(mconsole_get_request(req->originating_fd, req)){
		if(req->cmd->handler == mconsole_go) break;
		(*req->cmd->handler)(req);
	}
	os_set_fd_block(req->originating_fd, 0);
	reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
	mconsole_reply(req, "", 0, 0);
}

/* This list is populated by __initcall routines. */

LIST_HEAD(mconsole_devices);

void mconsole_register_dev(struct mc_device *new)
{
	list_add(&new->list, &mconsole_devices);
}

static struct mc_device *mconsole_find_dev(char *name)
{
	struct list_head *ele;
	struct mc_device *dev;

	list_for_each(ele, &mconsole_devices){
		dev = list_entry(ele, struct mc_device, list);
		if(!strncmp(name, dev->name, strlen(dev->name)))
			return(dev);
	}
	return(NULL);
}

#define CONFIG_BUF_SIZE 64

static void mconsole_get_config(int (*get_config)(char *, char *, int, 
						  char **),
				struct mc_request *req, char *name)
{
	char default_buf[CONFIG_BUF_SIZE], *error, *buf;
	int n, size;

	if(get_config == NULL){
		mconsole_reply(req, "No get_config routine defined", 1, 0);
		return;
	}

	error = NULL;
	size = sizeof(default_buf)/sizeof(default_buf[0]);
	buf = default_buf;

	while(1){
		n = (*get_config)(name, buf, size, &error);
		if(error != NULL){
			mconsole_reply(req, error, 1, 0);
			goto out;
		}

		if(n <= size){
			mconsole_reply(req, buf, 0, 0);
			goto out;
		}

		if(buf != default_buf)
			kfree(buf);

		size = n;
		buf = kmalloc(size, GFP_KERNEL);
		if(buf == NULL){
			mconsole_reply(req, "Failed to allocate buffer", 1, 0);
			return;
		}
	}
 out:
	if(buf != default_buf)
		kfree(buf);
	
}

void mconsole_config(struct mc_request *req)
{
	struct mc_device *dev;
	char *ptr = req->request.data, *name;
	int err;

	ptr += strlen("config");
	while(isspace(*ptr)) ptr++;
	dev = mconsole_find_dev(ptr);
	if(dev == NULL){
		mconsole_reply(req, "Bad configuration option", 1, 0);
		return;
	}

	name = &ptr[strlen(dev->name)];
	ptr = name;
	while((*ptr != '=') && (*ptr != '\0'))
		ptr++;

	if(*ptr == '='){
		err = (*dev->config)(name);
		mconsole_reply(req, "", err, 0);
	}
	else mconsole_get_config(dev->get_config, req, name);
}

void mconsole_remove(struct mc_request *req)
{
	struct mc_device *dev;	
	char *ptr = req->request.data, *err_msg = "";
        char error[256];
	int err, start, end, n;

	ptr += strlen("remove");
	while(isspace(*ptr)) ptr++;
	dev = mconsole_find_dev(ptr);
	if(dev == NULL){
		mconsole_reply(req, "Bad remove option", 1, 0);
		return;
	}

        ptr = &ptr[strlen(dev->name)];

        err = 1;
        n = (*dev->id)(&ptr, &start, &end);
        if(n < 0){
                err_msg = "Couldn't parse device number";
                goto out;
        }
        else if((n < start) || (n > end)){
                sprintf(error, "Invalid device number - must be between "
                        "%d and %d", start, end);
                err_msg = error;
                goto out;
        }

	err = (*dev->remove)(n);
        switch(err){
        case -ENODEV:
                err_msg = "Device doesn't exist";
                break;
        case -EBUSY:
                err_msg = "Device is currently open";
                break;
        default:
                break;
        }
 out:
	mconsole_reply(req, err_msg, err, 0);
}

#ifdef CONFIG_MAGIC_SYSRQ
void mconsole_sysrq(struct mc_request *req)
{
	char *ptr = req->request.data;

	ptr += strlen("sysrq");
	while(isspace(*ptr)) ptr++;

	mconsole_reply(req, "", 0, 0);
	handle_sysrq(*ptr, &current->thread.regs, NULL);
}
#else
void mconsole_sysrq(struct mc_request *req)
{
	mconsole_reply(req, "Sysrq not compiled in", 1, 0);
}
#endif

/* Mconsole stack trace
 *  Added by Allan Graves, Jeff Dike
 *  Dumps a stacks registers to the linux console.
 *  Usage stack <pid>.
 */
void do_stack(struct mc_request *req)
{
        char *ptr = req->request.data;
        int pid_requested= -1;
        struct task_struct *from = NULL;
	struct task_struct *to = NULL;

        /* Would be nice:
         * 1) Send showregs output to mconsole.
	 * 2) Add a way to stack dump all pids.
	 */

        ptr += strlen("stack");
        while(isspace(*ptr)) ptr++;

        /* Should really check for multiple pids or reject bad args here */
        /* What do the arguments in mconsole_reply mean? */
        if(sscanf(ptr, "%d", &pid_requested) == 0){
                mconsole_reply(req, "Please specify a pid", 1, 0);
                return;
        }

        from = current;
        to = find_task_by_pid(pid_requested);

        if((to == NULL) || (pid_requested == 0)) {
                mconsole_reply(req, "Couldn't find that pid", 1, 0);
                return;
        }
        to->thread.saved_task = current;

        switch_to(from, to, from);
        mconsole_reply(req, "Stack Dumped to console and message log", 0, 0);
}

void mconsole_stack(struct mc_request *req)
{
	/* This command doesn't work in TT mode, so let's check and then
	 * get out of here
	 */
	CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
				   1, 0),
		    do_stack(req));
}

/* Changed by mconsole_setup, which is __setup, and called before SMP is
 * active.
 */
static char *notify_socket = NULL; 

int mconsole_init(void)
{
	/* long to avoid size mismatch warnings from gcc */
	long sock;
	int err;
	char file[256];

	if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
	snprintf(mconsole_socket_name, sizeof(file), "%s", file);

	sock = os_create_unix_socket(file, sizeof(file), 1);
	if (sock < 0){
		printk("Failed to initialize management console\n");
		return(1);
	}

	register_reboot_notifier(&reboot_notifier);

	err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
			     SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
			     "mconsole", (void *)sock);
	if (err){
		printk("Failed to get IRQ for management console\n");
		return(1);
	}

	if(notify_socket != NULL){
		notify_socket = uml_strdup(notify_socket);
		if(notify_socket != NULL)
			mconsole_notify(notify_socket, MCONSOLE_SOCKET,
					mconsole_socket_name, 
					strlen(mconsole_socket_name) + 1);
		else printk(KERN_ERR "mconsole_setup failed to strdup "
			    "string\n");
	}

	printk("mconsole (version %d) initialized on %s\n", 
	       MCONSOLE_VERSION, mconsole_socket_name);
	return(0);
}

__initcall(mconsole_init);

static int write_proc_mconsole(struct file *file, const char __user *buffer,
			       unsigned long count, void *data)
{
	char *buf;

	buf = kmalloc(count + 1, GFP_KERNEL);
	if(buf == NULL) 
		return(-ENOMEM);

	if(copy_from_user(buf, buffer, count)){
		count = -EFAULT;
		goto out;
	}

	buf[count] = '\0';

	mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
 out:
	kfree(buf);
	return(count);
}

static int create_proc_mconsole(void)
{
	struct proc_dir_entry *ent;

	if(notify_socket == NULL) return(0);

	ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
	if(ent == NULL){
		printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
		return(0);
	}

	ent->read_proc = NULL;
	ent->write_proc = write_proc_mconsole;
	return(0);
}

static DEFINE_SPINLOCK(notify_spinlock);

void lock_notify(void)
{
	spin_lock(&notify_spinlock);
}

void unlock_notify(void)
{
	spin_unlock(&notify_spinlock);
}

__initcall(create_proc_mconsole);

#define NOTIFY "=notify:"

static int mconsole_setup(char *str)
{
	if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
		str += strlen(NOTIFY);
		notify_socket = str;
	}
	else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
	return(1);
}

__setup("mconsole", mconsole_setup);

__uml_help(mconsole_setup,
"mconsole=notify:<socket>\n"
"    Requests that the mconsole driver send a message to the named Unix\n"
"    socket containing the name of the mconsole socket.  This also serves\n"
"    to notify outside processes when UML has booted far enough to respond\n"
"    to mconsole requests.\n\n"
);

static int notify_panic(struct notifier_block *self, unsigned long unused1,
			void *ptr)
{
	char *message = ptr;

	if(notify_socket == NULL) return(0);

	mconsole_notify(notify_socket, MCONSOLE_PANIC, message, 
			strlen(message) + 1);
	return(0);
}

static struct notifier_block panic_exit_notifier = {
	.notifier_call 		= notify_panic,
	.next 			= NULL,
	.priority 		= 1
};

static int add_notifier(void)
{
	notifier_chain_register(&panic_notifier_list, &panic_exit_notifier);
	return(0);
}

__initcall(add_notifier);

char *mconsole_notify_socket(void)
{
	return(notify_socket);
}

EXPORT_SYMBOL(mconsole_notify_socket);

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */