blob: 0c8869fdd14ebf9291eb700ccd099c910584910d [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * binfmt_misc.c
3 *
Jan Engelhardt96de0e22007-10-19 23:21:04 +02004 * Copyright (C) 1997 Richard Günther
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
6 * binfmt_misc detects binaries via a magic or filename extension and invokes
7 * a specified wrapper. This should obsolete binfmt_java, binfmt_em86 and
8 * binfmt_mz.
9 *
10 * 1997-04-25 first version
11 * [...]
12 * 1997-05-19 cleanup
13 * 1997-06-26 hpa: pass the real filename rather than argv[0]
14 * 1997-06-30 minor cleanup
15 * 1997-08-09 removed extension stripping, locking cleanup
16 * 2001-02-28 AV: rewritten into something that resembles C. Original didn't.
17 */
18
19#include <linux/module.h>
20#include <linux/init.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040021#include <linux/sched.h>
Muthu Kumarb502bd12012-03-23 15:01:50 -070022#include <linux/magic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/binfmts.h>
24#include <linux/slab.h>
25#include <linux/ctype.h>
26#include <linux/file.h>
27#include <linux/pagemap.h>
28#include <linux/namei.h>
29#include <linux/mount.h>
30#include <linux/syscalls.h>
Akinobu Mita6e2c10a2008-07-23 21:29:15 -070031#include <linux/fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33#include <asm/uaccess.h>
34
35enum {
36 VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
37};
38
39static LIST_HEAD(entries);
40static int enabled = 1;
41
42enum {Enabled, Magic};
43#define MISC_FMT_PRESERVE_ARGV0 (1<<31)
44#define MISC_FMT_OPEN_BINARY (1<<30)
45#define MISC_FMT_CREDENTIALS (1<<29)
46
47typedef struct {
48 struct list_head list;
49 unsigned long flags; /* type, status, etc. */
50 int offset; /* offset of magic */
51 int size; /* size of magic/mask */
52 char *magic; /* magic or filename extension */
53 char *mask; /* mask, NULL for exact match */
54 char *interpreter; /* filename of interpreter */
55 char *name;
56 struct dentry *dentry;
57} Node;
58
59static DEFINE_RWLOCK(entries_lock);
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -040060static struct file_system_type bm_fs_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061static struct vfsmount *bm_mnt;
62static int entry_count;
63
64/*
65 * Check if we support the binfmt
66 * if we do, return the node, else NULL
67 * locking is done in load_misc_binary
68 */
69static Node *check_file(struct linux_binprm *bprm)
70{
71 char *p = strrchr(bprm->interp, '.');
72 struct list_head *l;
73
74 list_for_each(l, &entries) {
75 Node *e = list_entry(l, Node, list);
76 char *s;
77 int j;
78
79 if (!test_bit(Enabled, &e->flags))
80 continue;
81
82 if (!test_bit(Magic, &e->flags)) {
83 if (p && !strcmp(e->magic, p + 1))
84 return e;
85 continue;
86 }
87
88 s = bprm->buf + e->offset;
89 if (e->mask) {
90 for (j = 0; j < e->size; j++)
91 if ((*s++ ^ e->magic[j]) & e->mask[j])
92 break;
93 } else {
94 for (j = 0; j < e->size; j++)
95 if ((*s++ ^ e->magic[j]))
96 break;
97 }
98 if (j == e->size)
99 return e;
100 }
101 return NULL;
102}
103
104/*
105 * the loader itself
106 */
Al Viro71613c32012-10-20 22:00:48 -0400107static int load_misc_binary(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
109 Node *fmt;
110 struct file * interp_file = NULL;
111 char iname[BINPRM_BUF_SIZE];
David Howellsd7627462010-08-17 23:52:56 +0100112 const char *iname_addr = iname;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 int retval;
114 int fd_binary = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
116 retval = -ENOEXEC;
117 if (!enabled)
118 goto _ret;
119
120 /* to keep locking time low, we copy the interpreter string */
121 read_lock(&entries_lock);
122 fmt = check_file(bprm);
123 if (fmt)
124 strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE);
125 read_unlock(&entries_lock);
126 if (!fmt)
127 goto _ret;
128
129 if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700130 retval = remove_arg_zero(bprm);
131 if (retval)
132 goto _ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 }
134
135 if (fmt->flags & MISC_FMT_OPEN_BINARY) {
136
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 /* if the binary should be opened on behalf of the
138 * interpreter than keep it open and assign descriptor
139 * to it */
140 fd_binary = get_unused_fd();
141 if (fd_binary < 0) {
142 retval = fd_binary;
Al Virofd8328b2008-04-22 05:11:59 -0400143 goto _ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 }
145 fd_install(fd_binary, bprm->file);
146
147 /* if the binary is not readable than enforce mm->dumpable=0
148 regardless of the interpreter's permissions */
Al Viro1b5d7832011-06-19 12:49:47 -0400149 would_dump(bprm, bprm->file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
151 allow_write_access(bprm->file);
152 bprm->file = NULL;
153
154 /* mark the bprm that fd should be passed to interp */
155 bprm->interp_flags |= BINPRM_FLAGS_EXECFD;
156 bprm->interp_data = fd_binary;
157
158 } else {
159 allow_write_access(bprm->file);
160 fput(bprm->file);
161 bprm->file = NULL;
162 }
163 /* make argv[1] be the path to the binary */
164 retval = copy_strings_kernel (1, &bprm->interp, bprm);
165 if (retval < 0)
166 goto _error;
167 bprm->argc++;
168
169 /* add the interp as argv[0] */
170 retval = copy_strings_kernel (1, &iname_addr, bprm);
171 if (retval < 0)
172 goto _error;
173 bprm->argc ++;
174
Kees Cookb66c5982012-12-20 15:05:16 -0800175 /* Update interp in case binfmt_script needs it. */
176 retval = bprm_change_interp(iname, bprm);
177 if (retval < 0)
178 goto _error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
180 interp_file = open_exec (iname);
181 retval = PTR_ERR (interp_file);
182 if (IS_ERR (interp_file))
183 goto _error;
184
185 bprm->file = interp_file;
186 if (fmt->flags & MISC_FMT_CREDENTIALS) {
187 /*
188 * No need to call prepare_binprm(), it's already been
189 * done. bprm->buf is stale, update from interp_file.
190 */
191 memset(bprm->buf, 0, BINPRM_BUF_SIZE);
192 retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
193 } else
194 retval = prepare_binprm (bprm);
195
196 if (retval < 0)
197 goto _error;
198
Al Viro3c456bf2012-10-20 21:53:31 -0400199 retval = search_binary_handler(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 if (retval < 0)
201 goto _error;
202
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203_ret:
204 return retval;
205_error:
206 if (fd_binary > 0)
207 sys_close(fd_binary);
208 bprm->interp_flags = 0;
209 bprm->interp_data = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 goto _ret;
211}
212
213/* Command parsers */
214
215/*
216 * parses and copies one argument enclosed in del from *sp to *dp,
217 * recognising the \x special.
218 * returns pointer to the copied argument or NULL in case of an
219 * error (and sets err) or null argument length.
220 */
221static char *scanarg(char *s, char del)
222{
223 char c;
224
225 while ((c = *s++) != del) {
226 if (c == '\\' && *s == 'x') {
227 s++;
228 if (!isxdigit(*s++))
229 return NULL;
230 if (!isxdigit(*s++))
231 return NULL;
232 }
233 }
234 return s;
235}
236
237static int unquote(char *from)
238{
239 char c = 0, *s = from, *p = from;
240
241 while ((c = *s++) != '\0') {
242 if (c == '\\' && *s == 'x') {
243 s++;
244 c = toupper(*s++);
245 *p = (c - (isdigit(c) ? '0' : 'A' - 10)) << 4;
246 c = toupper(*s++);
247 *p++ |= c - (isdigit(c) ? '0' : 'A' - 10);
248 continue;
249 }
250 *p++ = c;
251 }
252 return p - from;
253}
254
Arjan van de Ven858119e2006-01-14 13:20:43 -0800255static char * check_special_flags (char * sfs, Node * e)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256{
257 char * p = sfs;
258 int cont = 1;
259
260 /* special flags */
261 while (cont) {
262 switch (*p) {
263 case 'P':
264 p++;
265 e->flags |= MISC_FMT_PRESERVE_ARGV0;
266 break;
267 case 'O':
268 p++;
269 e->flags |= MISC_FMT_OPEN_BINARY;
270 break;
271 case 'C':
272 p++;
273 /* this flags also implies the
274 open-binary flag */
275 e->flags |= (MISC_FMT_CREDENTIALS |
276 MISC_FMT_OPEN_BINARY);
277 break;
278 default:
279 cont = 0;
280 }
281 }
282
283 return p;
284}
285/*
286 * This registers a new binary format, it recognises the syntax
287 * ':name:type:offset:magic:mask:interpreter:flags'
288 * where the ':' is the IFS, that can be chosen with the first char
289 */
290static Node *create_entry(const char __user *buffer, size_t count)
291{
292 Node *e;
293 int memsize, err;
294 char *buf, *p;
295 char del;
296
297 /* some sanity checks */
298 err = -EINVAL;
299 if ((count < 11) || (count > 256))
300 goto out;
301
302 err = -ENOMEM;
303 memsize = sizeof(Node) + count + 8;
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800304 e = kmalloc(memsize, GFP_USER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 if (!e)
306 goto out;
307
308 p = buf = (char *)e + sizeof(Node);
309
310 memset(e, 0, sizeof(Node));
311 if (copy_from_user(buf, buffer, count))
312 goto Efault;
313
314 del = *p++; /* delimeter */
315
316 memset(buf+count, del, 8);
317
318 e->name = p;
319 p = strchr(p, del);
320 if (!p)
321 goto Einval;
322 *p++ = '\0';
323 if (!e->name[0] ||
324 !strcmp(e->name, ".") ||
325 !strcmp(e->name, "..") ||
326 strchr(e->name, '/'))
327 goto Einval;
328 switch (*p++) {
329 case 'E': e->flags = 1<<Enabled; break;
330 case 'M': e->flags = (1<<Enabled) | (1<<Magic); break;
331 default: goto Einval;
332 }
333 if (*p++ != del)
334 goto Einval;
335 if (test_bit(Magic, &e->flags)) {
336 char *s = strchr(p, del);
337 if (!s)
338 goto Einval;
339 *s++ = '\0';
340 e->offset = simple_strtoul(p, &p, 10);
341 if (*p++)
342 goto Einval;
343 e->magic = p;
344 p = scanarg(p, del);
345 if (!p)
346 goto Einval;
347 p[-1] = '\0';
348 if (!e->magic[0])
349 goto Einval;
350 e->mask = p;
351 p = scanarg(p, del);
352 if (!p)
353 goto Einval;
354 p[-1] = '\0';
355 if (!e->mask[0])
356 e->mask = NULL;
357 e->size = unquote(e->magic);
358 if (e->mask && unquote(e->mask) != e->size)
359 goto Einval;
360 if (e->size + e->offset > BINPRM_BUF_SIZE)
361 goto Einval;
362 } else {
363 p = strchr(p, del);
364 if (!p)
365 goto Einval;
366 *p++ = '\0';
367 e->magic = p;
368 p = strchr(p, del);
369 if (!p)
370 goto Einval;
371 *p++ = '\0';
372 if (!e->magic[0] || strchr(e->magic, '/'))
373 goto Einval;
374 p = strchr(p, del);
375 if (!p)
376 goto Einval;
377 *p++ = '\0';
378 }
379 e->interpreter = p;
380 p = strchr(p, del);
381 if (!p)
382 goto Einval;
383 *p++ = '\0';
384 if (!e->interpreter[0])
385 goto Einval;
386
387
388 p = check_special_flags (p, e);
389
390 if (*p == '\n')
391 p++;
392 if (p != buf + count)
393 goto Einval;
394 return e;
395
396out:
397 return ERR_PTR(err);
398
399Efault:
400 kfree(e);
401 return ERR_PTR(-EFAULT);
402Einval:
403 kfree(e);
404 return ERR_PTR(-EINVAL);
405}
406
407/*
408 * Set status of entry/binfmt_misc:
409 * '1' enables, '0' disables and '-1' clears entry/binfmt_misc
410 */
411static int parse_command(const char __user *buffer, size_t count)
412{
413 char s[4];
414
415 if (!count)
416 return 0;
417 if (count > 3)
418 return -EINVAL;
419 if (copy_from_user(s, buffer, count))
420 return -EFAULT;
421 if (s[count-1] == '\n')
422 count--;
423 if (count == 1 && s[0] == '0')
424 return 1;
425 if (count == 1 && s[0] == '1')
426 return 2;
427 if (count == 2 && s[0] == '-' && s[1] == '1')
428 return 3;
429 return -EINVAL;
430}
431
432/* generic stuff */
433
434static void entry_status(Node *e, char *page)
435{
436 char *dp;
437 char *status = "disabled";
438 const char * flags = "flags: ";
439
440 if (test_bit(Enabled, &e->flags))
441 status = "enabled";
442
443 if (!VERBOSE_STATUS) {
444 sprintf(page, "%s\n", status);
445 return;
446 }
447
448 sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter);
449 dp = page + strlen(page);
450
451 /* print the special flags */
452 sprintf (dp, "%s", flags);
453 dp += strlen (flags);
454 if (e->flags & MISC_FMT_PRESERVE_ARGV0) {
455 *dp ++ = 'P';
456 }
457 if (e->flags & MISC_FMT_OPEN_BINARY) {
458 *dp ++ = 'O';
459 }
460 if (e->flags & MISC_FMT_CREDENTIALS) {
461 *dp ++ = 'C';
462 }
463 *dp ++ = '\n';
464
465
466 if (!test_bit(Magic, &e->flags)) {
467 sprintf(dp, "extension .%s\n", e->magic);
468 } else {
469 int i;
470
471 sprintf(dp, "offset %i\nmagic ", e->offset);
472 dp = page + strlen(page);
473 for (i = 0; i < e->size; i++) {
474 sprintf(dp, "%02x", 0xff & (int) (e->magic[i]));
475 dp += 2;
476 }
477 if (e->mask) {
478 sprintf(dp, "\nmask ");
479 dp += 6;
480 for (i = 0; i < e->size; i++) {
481 sprintf(dp, "%02x", 0xff & (int) (e->mask[i]));
482 dp += 2;
483 }
484 }
485 *dp++ = '\n';
486 *dp = '\0';
487 }
488}
489
490static struct inode *bm_get_inode(struct super_block *sb, int mode)
491{
492 struct inode * inode = new_inode(sb);
493
494 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -0400495 inode->i_ino = get_next_ino();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 inode->i_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 inode->i_atime = inode->i_mtime = inode->i_ctime =
498 current_fs_time(inode->i_sb);
499 }
500 return inode;
501}
502
Al Virob57922d2010-06-07 14:34:48 -0400503static void bm_evict_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504{
Jan Karadbd57682012-05-03 14:48:02 +0200505 clear_inode(inode);
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700506 kfree(inode->i_private);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507}
508
509static void kill_node(Node *e)
510{
511 struct dentry *dentry;
512
513 write_lock(&entries_lock);
514 dentry = e->dentry;
515 if (dentry) {
516 list_del_init(&e->list);
517 e->dentry = NULL;
518 }
519 write_unlock(&entries_lock);
520
521 if (dentry) {
Miklos Szeredi6d6b77f2011-10-28 14:13:28 +0200522 drop_nlink(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 d_drop(dentry);
524 dput(dentry);
525 simple_release_fs(&bm_mnt, &entry_count);
526 }
527}
528
529/* /<entry> */
530
531static ssize_t
532bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
533{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800534 Node *e = file->f_path.dentry->d_inode->i_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 ssize_t res;
536 char *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537
538 if (!(page = (char*) __get_free_page(GFP_KERNEL)))
539 return -ENOMEM;
540
541 entry_status(e, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
Akinobu Mita6e2c10a2008-07-23 21:29:15 -0700543 res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page));
544
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 free_page((unsigned long) page);
546 return res;
547}
548
549static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
550 size_t count, loff_t *ppos)
551{
552 struct dentry *root;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800553 Node *e = file->f_path.dentry->d_inode->i_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 int res = parse_command(buffer, count);
555
556 switch (res) {
557 case 1: clear_bit(Enabled, &e->flags);
558 break;
559 case 2: set_bit(Enabled, &e->flags);
560 break;
Al Virod8c95842011-12-07 18:16:57 -0500561 case 3: root = dget(file->f_path.dentry->d_sb->s_root);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800562 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563
564 kill_node(e);
565
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800566 mutex_unlock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 dput(root);
568 break;
569 default: return res;
570 }
571 return count;
572}
573
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800574static const struct file_operations bm_entry_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 .read = bm_entry_read,
576 .write = bm_entry_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200577 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578};
579
580/* /register */
581
582static ssize_t bm_register_write(struct file *file, const char __user *buffer,
583 size_t count, loff_t *ppos)
584{
585 Node *e;
586 struct inode *inode;
587 struct dentry *root, *dentry;
Al Virod8c95842011-12-07 18:16:57 -0500588 struct super_block *sb = file->f_path.dentry->d_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 int err = 0;
590
591 e = create_entry(buffer, count);
592
593 if (IS_ERR(e))
594 return PTR_ERR(e);
595
596 root = dget(sb->s_root);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800597 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 dentry = lookup_one_len(e->name, root, strlen(e->name));
599 err = PTR_ERR(dentry);
600 if (IS_ERR(dentry))
601 goto out;
602
603 err = -EEXIST;
604 if (dentry->d_inode)
605 goto out2;
606
607 inode = bm_get_inode(sb, S_IFREG | 0644);
608
609 err = -ENOMEM;
610 if (!inode)
611 goto out2;
612
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400613 err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 if (err) {
615 iput(inode);
616 inode = NULL;
617 goto out2;
618 }
619
620 e->dentry = dget(dentry);
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700621 inode->i_private = e;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 inode->i_fop = &bm_entry_operations;
623
624 d_instantiate(dentry, inode);
625 write_lock(&entries_lock);
626 list_add(&e->list, &entries);
627 write_unlock(&entries_lock);
628
629 err = 0;
630out2:
631 dput(dentry);
632out:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800633 mutex_unlock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 dput(root);
635
636 if (err) {
637 kfree(e);
638 return -EINVAL;
639 }
640 return count;
641}
642
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800643static const struct file_operations bm_register_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 .write = bm_register_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200645 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646};
647
648/* /status */
649
650static ssize_t
651bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
652{
Qinghuang Feng87113e82009-01-06 14:41:38 -0800653 char *s = enabled ? "enabled\n" : "disabled\n";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654
Akinobu Mita92f4c702007-05-09 02:33:32 -0700655 return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656}
657
658static ssize_t bm_status_write(struct file * file, const char __user * buffer,
659 size_t count, loff_t *ppos)
660{
661 int res = parse_command(buffer, count);
662 struct dentry *root;
663
664 switch (res) {
665 case 1: enabled = 0; break;
666 case 2: enabled = 1; break;
Al Virod8c95842011-12-07 18:16:57 -0500667 case 3: root = dget(file->f_path.dentry->d_sb->s_root);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800668 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669
670 while (!list_empty(&entries))
671 kill_node(list_entry(entries.next, Node, list));
672
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800673 mutex_unlock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 dput(root);
675 default: return res;
676 }
677 return count;
678}
679
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800680static const struct file_operations bm_status_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 .read = bm_status_read,
682 .write = bm_status_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200683 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684};
685
686/* Superblock handling */
687
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800688static const struct super_operations s_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 .statfs = simple_statfs,
Al Virob57922d2010-06-07 14:34:48 -0400690 .evict_inode = bm_evict_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691};
692
693static int bm_fill_super(struct super_block * sb, void * data, int silent)
694{
695 static struct tree_descr bm_files[] = {
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700696 [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
697 [3] = {"register", &bm_register_operations, S_IWUSR},
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 /* last one */ {""}
699 };
Muthu Kumarb502bd12012-03-23 15:01:50 -0700700 int err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 if (!err)
702 sb->s_op = &s_ops;
703 return err;
704}
705
Al Virofc14f2f2010-07-25 01:48:30 +0400706static struct dentry *bm_mount(struct file_system_type *fs_type,
707 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708{
Al Virofc14f2f2010-07-25 01:48:30 +0400709 return mount_single(fs_type, flags, data, bm_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710}
711
712static struct linux_binfmt misc_format = {
713 .module = THIS_MODULE,
714 .load_binary = load_misc_binary,
715};
716
717static struct file_system_type bm_fs_type = {
718 .owner = THIS_MODULE,
719 .name = "binfmt_misc",
Al Virofc14f2f2010-07-25 01:48:30 +0400720 .mount = bm_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 .kill_sb = kill_litter_super,
722};
723
724static int __init init_misc_binfmt(void)
725{
726 int err = register_filesystem(&bm_fs_type);
Al Viro8fc3dc52012-03-17 03:05:16 -0400727 if (!err)
728 insert_binfmt(&misc_format);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 return err;
730}
731
732static void __exit exit_misc_binfmt(void)
733{
734 unregister_binfmt(&misc_format);
735 unregister_filesystem(&bm_fs_type);
736}
737
738core_initcall(init_misc_binfmt);
739module_exit(exit_misc_binfmt);
740MODULE_LICENSE("GPL");