blob: 1e9edbdeda7ebcbe243b299d46859c4917f0e217 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/binfmts.h>
23#include <linux/slab.h>
24#include <linux/ctype.h>
25#include <linux/file.h>
26#include <linux/pagemap.h>
27#include <linux/namei.h>
28#include <linux/mount.h>
29#include <linux/syscalls.h>
Akinobu Mita6e2c10a2008-07-23 21:29:15 -070030#include <linux/fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32#include <asm/uaccess.h>
33
34enum {
35 VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
36};
37
38static LIST_HEAD(entries);
39static int enabled = 1;
40
41enum {Enabled, Magic};
42#define MISC_FMT_PRESERVE_ARGV0 (1<<31)
43#define MISC_FMT_OPEN_BINARY (1<<30)
44#define MISC_FMT_CREDENTIALS (1<<29)
45
46typedef struct {
47 struct list_head list;
48 unsigned long flags; /* type, status, etc. */
49 int offset; /* offset of magic */
50 int size; /* size of magic/mask */
51 char *magic; /* magic or filename extension */
52 char *mask; /* mask, NULL for exact match */
53 char *interpreter; /* filename of interpreter */
54 char *name;
55 struct dentry *dentry;
56} Node;
57
58static DEFINE_RWLOCK(entries_lock);
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -040059static struct file_system_type bm_fs_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060static struct vfsmount *bm_mnt;
61static int entry_count;
62
63/*
64 * Check if we support the binfmt
65 * if we do, return the node, else NULL
66 * locking is done in load_misc_binary
67 */
68static Node *check_file(struct linux_binprm *bprm)
69{
70 char *p = strrchr(bprm->interp, '.');
71 struct list_head *l;
72
73 list_for_each(l, &entries) {
74 Node *e = list_entry(l, Node, list);
75 char *s;
76 int j;
77
78 if (!test_bit(Enabled, &e->flags))
79 continue;
80
81 if (!test_bit(Magic, &e->flags)) {
82 if (p && !strcmp(e->magic, p + 1))
83 return e;
84 continue;
85 }
86
87 s = bprm->buf + e->offset;
88 if (e->mask) {
89 for (j = 0; j < e->size; j++)
90 if ((*s++ ^ e->magic[j]) & e->mask[j])
91 break;
92 } else {
93 for (j = 0; j < e->size; j++)
94 if ((*s++ ^ e->magic[j]))
95 break;
96 }
97 if (j == e->size)
98 return e;
99 }
100 return NULL;
101}
102
103/*
104 * the loader itself
105 */
106static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs)
107{
108 Node *fmt;
109 struct file * interp_file = NULL;
110 char iname[BINPRM_BUF_SIZE];
David Howellsd7627462010-08-17 23:52:56 +0100111 const char *iname_addr = iname;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 int retval;
113 int fd_binary = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
115 retval = -ENOEXEC;
116 if (!enabled)
117 goto _ret;
118
Pavel Emelyanov3a2e7f42008-04-29 00:59:24 -0700119 retval = -ENOEXEC;
Kirill A. Shutemovbf2a9a32008-10-15 22:02:39 -0700120 if (bprm->recursion_depth > BINPRM_MAX_RECURSION)
Pavel Emelyanov3a2e7f42008-04-29 00:59:24 -0700121 goto _ret;
122
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 /* to keep locking time low, we copy the interpreter string */
124 read_lock(&entries_lock);
125 fmt = check_file(bprm);
126 if (fmt)
127 strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE);
128 read_unlock(&entries_lock);
129 if (!fmt)
130 goto _ret;
131
132 if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700133 retval = remove_arg_zero(bprm);
134 if (retval)
135 goto _ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 }
137
138 if (fmt->flags & MISC_FMT_OPEN_BINARY) {
139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 /* if the binary should be opened on behalf of the
141 * interpreter than keep it open and assign descriptor
142 * to it */
143 fd_binary = get_unused_fd();
144 if (fd_binary < 0) {
145 retval = fd_binary;
Al Virofd8328b2008-04-22 05:11:59 -0400146 goto _ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 }
148 fd_install(fd_binary, bprm->file);
149
150 /* if the binary is not readable than enforce mm->dumpable=0
151 regardless of the interpreter's permissions */
Al Viro1b5d7832011-06-19 12:49:47 -0400152 would_dump(bprm, bprm->file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
154 allow_write_access(bprm->file);
155 bprm->file = NULL;
156
157 /* mark the bprm that fd should be passed to interp */
158 bprm->interp_flags |= BINPRM_FLAGS_EXECFD;
159 bprm->interp_data = fd_binary;
160
161 } else {
162 allow_write_access(bprm->file);
163 fput(bprm->file);
164 bprm->file = NULL;
165 }
166 /* make argv[1] be the path to the binary */
167 retval = copy_strings_kernel (1, &bprm->interp, bprm);
168 if (retval < 0)
169 goto _error;
170 bprm->argc++;
171
172 /* add the interp as argv[0] */
173 retval = copy_strings_kernel (1, &iname_addr, bprm);
174 if (retval < 0)
175 goto _error;
176 bprm->argc ++;
177
178 bprm->interp = iname; /* for binfmt_script */
179
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
Kirill A. Shutemovbf2a9a32008-10-15 22:02:39 -0700199 bprm->recursion_depth++;
Pavel Emelyanovff9bc512008-08-20 14:09:10 -0700200
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 retval = search_binary_handler (bprm, regs);
202 if (retval < 0)
203 goto _error;
204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205_ret:
206 return retval;
207_error:
208 if (fd_binary > 0)
209 sys_close(fd_binary);
210 bprm->interp_flags = 0;
211 bprm->interp_data = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 goto _ret;
213}
214
215/* Command parsers */
216
217/*
218 * parses and copies one argument enclosed in del from *sp to *dp,
219 * recognising the \x special.
220 * returns pointer to the copied argument or NULL in case of an
221 * error (and sets err) or null argument length.
222 */
223static char *scanarg(char *s, char del)
224{
225 char c;
226
227 while ((c = *s++) != del) {
228 if (c == '\\' && *s == 'x') {
229 s++;
230 if (!isxdigit(*s++))
231 return NULL;
232 if (!isxdigit(*s++))
233 return NULL;
234 }
235 }
236 return s;
237}
238
239static int unquote(char *from)
240{
241 char c = 0, *s = from, *p = from;
242
243 while ((c = *s++) != '\0') {
244 if (c == '\\' && *s == 'x') {
245 s++;
246 c = toupper(*s++);
247 *p = (c - (isdigit(c) ? '0' : 'A' - 10)) << 4;
248 c = toupper(*s++);
249 *p++ |= c - (isdigit(c) ? '0' : 'A' - 10);
250 continue;
251 }
252 *p++ = c;
253 }
254 return p - from;
255}
256
Arjan van de Ven858119e2006-01-14 13:20:43 -0800257static char * check_special_flags (char * sfs, Node * e)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258{
259 char * p = sfs;
260 int cont = 1;
261
262 /* special flags */
263 while (cont) {
264 switch (*p) {
265 case 'P':
266 p++;
267 e->flags |= MISC_FMT_PRESERVE_ARGV0;
268 break;
269 case 'O':
270 p++;
271 e->flags |= MISC_FMT_OPEN_BINARY;
272 break;
273 case 'C':
274 p++;
275 /* this flags also implies the
276 open-binary flag */
277 e->flags |= (MISC_FMT_CREDENTIALS |
278 MISC_FMT_OPEN_BINARY);
279 break;
280 default:
281 cont = 0;
282 }
283 }
284
285 return p;
286}
287/*
288 * This registers a new binary format, it recognises the syntax
289 * ':name:type:offset:magic:mask:interpreter:flags'
290 * where the ':' is the IFS, that can be chosen with the first char
291 */
292static Node *create_entry(const char __user *buffer, size_t count)
293{
294 Node *e;
295 int memsize, err;
296 char *buf, *p;
297 char del;
298
299 /* some sanity checks */
300 err = -EINVAL;
301 if ((count < 11) || (count > 256))
302 goto out;
303
304 err = -ENOMEM;
305 memsize = sizeof(Node) + count + 8;
Robert P. J. Day5cbded52006-12-13 00:35:56 -0800306 e = kmalloc(memsize, GFP_USER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 if (!e)
308 goto out;
309
310 p = buf = (char *)e + sizeof(Node);
311
312 memset(e, 0, sizeof(Node));
313 if (copy_from_user(buf, buffer, count))
314 goto Efault;
315
316 del = *p++; /* delimeter */
317
318 memset(buf+count, del, 8);
319
320 e->name = p;
321 p = strchr(p, del);
322 if (!p)
323 goto Einval;
324 *p++ = '\0';
325 if (!e->name[0] ||
326 !strcmp(e->name, ".") ||
327 !strcmp(e->name, "..") ||
328 strchr(e->name, '/'))
329 goto Einval;
330 switch (*p++) {
331 case 'E': e->flags = 1<<Enabled; break;
332 case 'M': e->flags = (1<<Enabled) | (1<<Magic); break;
333 default: goto Einval;
334 }
335 if (*p++ != del)
336 goto Einval;
337 if (test_bit(Magic, &e->flags)) {
338 char *s = strchr(p, del);
339 if (!s)
340 goto Einval;
341 *s++ = '\0';
342 e->offset = simple_strtoul(p, &p, 10);
343 if (*p++)
344 goto Einval;
345 e->magic = p;
346 p = scanarg(p, del);
347 if (!p)
348 goto Einval;
349 p[-1] = '\0';
350 if (!e->magic[0])
351 goto Einval;
352 e->mask = p;
353 p = scanarg(p, del);
354 if (!p)
355 goto Einval;
356 p[-1] = '\0';
357 if (!e->mask[0])
358 e->mask = NULL;
359 e->size = unquote(e->magic);
360 if (e->mask && unquote(e->mask) != e->size)
361 goto Einval;
362 if (e->size + e->offset > BINPRM_BUF_SIZE)
363 goto Einval;
364 } else {
365 p = strchr(p, del);
366 if (!p)
367 goto Einval;
368 *p++ = '\0';
369 e->magic = p;
370 p = strchr(p, del);
371 if (!p)
372 goto Einval;
373 *p++ = '\0';
374 if (!e->magic[0] || strchr(e->magic, '/'))
375 goto Einval;
376 p = strchr(p, del);
377 if (!p)
378 goto Einval;
379 *p++ = '\0';
380 }
381 e->interpreter = p;
382 p = strchr(p, del);
383 if (!p)
384 goto Einval;
385 *p++ = '\0';
386 if (!e->interpreter[0])
387 goto Einval;
388
389
390 p = check_special_flags (p, e);
391
392 if (*p == '\n')
393 p++;
394 if (p != buf + count)
395 goto Einval;
396 return e;
397
398out:
399 return ERR_PTR(err);
400
401Efault:
402 kfree(e);
403 return ERR_PTR(-EFAULT);
404Einval:
405 kfree(e);
406 return ERR_PTR(-EINVAL);
407}
408
409/*
410 * Set status of entry/binfmt_misc:
411 * '1' enables, '0' disables and '-1' clears entry/binfmt_misc
412 */
413static int parse_command(const char __user *buffer, size_t count)
414{
415 char s[4];
416
417 if (!count)
418 return 0;
419 if (count > 3)
420 return -EINVAL;
421 if (copy_from_user(s, buffer, count))
422 return -EFAULT;
423 if (s[count-1] == '\n')
424 count--;
425 if (count == 1 && s[0] == '0')
426 return 1;
427 if (count == 1 && s[0] == '1')
428 return 2;
429 if (count == 2 && s[0] == '-' && s[1] == '1')
430 return 3;
431 return -EINVAL;
432}
433
434/* generic stuff */
435
436static void entry_status(Node *e, char *page)
437{
438 char *dp;
439 char *status = "disabled";
440 const char * flags = "flags: ";
441
442 if (test_bit(Enabled, &e->flags))
443 status = "enabled";
444
445 if (!VERBOSE_STATUS) {
446 sprintf(page, "%s\n", status);
447 return;
448 }
449
450 sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter);
451 dp = page + strlen(page);
452
453 /* print the special flags */
454 sprintf (dp, "%s", flags);
455 dp += strlen (flags);
456 if (e->flags & MISC_FMT_PRESERVE_ARGV0) {
457 *dp ++ = 'P';
458 }
459 if (e->flags & MISC_FMT_OPEN_BINARY) {
460 *dp ++ = 'O';
461 }
462 if (e->flags & MISC_FMT_CREDENTIALS) {
463 *dp ++ = 'C';
464 }
465 *dp ++ = '\n';
466
467
468 if (!test_bit(Magic, &e->flags)) {
469 sprintf(dp, "extension .%s\n", e->magic);
470 } else {
471 int i;
472
473 sprintf(dp, "offset %i\nmagic ", e->offset);
474 dp = page + strlen(page);
475 for (i = 0; i < e->size; i++) {
476 sprintf(dp, "%02x", 0xff & (int) (e->magic[i]));
477 dp += 2;
478 }
479 if (e->mask) {
480 sprintf(dp, "\nmask ");
481 dp += 6;
482 for (i = 0; i < e->size; i++) {
483 sprintf(dp, "%02x", 0xff & (int) (e->mask[i]));
484 dp += 2;
485 }
486 }
487 *dp++ = '\n';
488 *dp = '\0';
489 }
490}
491
492static struct inode *bm_get_inode(struct super_block *sb, int mode)
493{
494 struct inode * inode = new_inode(sb);
495
496 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -0400497 inode->i_ino = get_next_ino();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 inode->i_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 inode->i_atime = inode->i_mtime = inode->i_ctime =
500 current_fs_time(inode->i_sb);
501 }
502 return inode;
503}
504
Al Virob57922d2010-06-07 14:34:48 -0400505static void bm_evict_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506{
Al Virob57922d2010-06-07 14:34:48 -0400507 end_writeback(inode);
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700508 kfree(inode->i_private);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509}
510
511static void kill_node(Node *e)
512{
513 struct dentry *dentry;
514
515 write_lock(&entries_lock);
516 dentry = e->dentry;
517 if (dentry) {
518 list_del_init(&e->list);
519 e->dentry = NULL;
520 }
521 write_unlock(&entries_lock);
522
523 if (dentry) {
Miklos Szeredi6d6b77f2011-10-28 14:13:28 +0200524 drop_nlink(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 d_drop(dentry);
526 dput(dentry);
527 simple_release_fs(&bm_mnt, &entry_count);
528 }
529}
530
531/* /<entry> */
532
533static ssize_t
534bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
535{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800536 Node *e = file->f_path.dentry->d_inode->i_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 ssize_t res;
538 char *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
540 if (!(page = (char*) __get_free_page(GFP_KERNEL)))
541 return -ENOMEM;
542
543 entry_status(e, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544
Akinobu Mita6e2c10a2008-07-23 21:29:15 -0700545 res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page));
546
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 free_page((unsigned long) page);
548 return res;
549}
550
551static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
552 size_t count, loff_t *ppos)
553{
554 struct dentry *root;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800555 Node *e = file->f_path.dentry->d_inode->i_private;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 int res = parse_command(buffer, count);
557
558 switch (res) {
559 case 1: clear_bit(Enabled, &e->flags);
560 break;
561 case 2: set_bit(Enabled, &e->flags);
562 break;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800563 case 3: root = dget(file->f_path.mnt->mnt_sb->s_root);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800564 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
566 kill_node(e);
567
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800568 mutex_unlock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 dput(root);
570 break;
571 default: return res;
572 }
573 return count;
574}
575
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800576static const struct file_operations bm_entry_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 .read = bm_entry_read,
578 .write = bm_entry_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200579 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580};
581
582/* /register */
583
584static ssize_t bm_register_write(struct file *file, const char __user *buffer,
585 size_t count, loff_t *ppos)
586{
587 Node *e;
588 struct inode *inode;
589 struct dentry *root, *dentry;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800590 struct super_block *sb = file->f_path.mnt->mnt_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 int err = 0;
592
593 e = create_entry(buffer, count);
594
595 if (IS_ERR(e))
596 return PTR_ERR(e);
597
598 root = dget(sb->s_root);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800599 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 dentry = lookup_one_len(e->name, root, strlen(e->name));
601 err = PTR_ERR(dentry);
602 if (IS_ERR(dentry))
603 goto out;
604
605 err = -EEXIST;
606 if (dentry->d_inode)
607 goto out2;
608
609 inode = bm_get_inode(sb, S_IFREG | 0644);
610
611 err = -ENOMEM;
612 if (!inode)
613 goto out2;
614
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400615 err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 if (err) {
617 iput(inode);
618 inode = NULL;
619 goto out2;
620 }
621
622 e->dentry = dget(dentry);
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700623 inode->i_private = e;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 inode->i_fop = &bm_entry_operations;
625
626 d_instantiate(dentry, inode);
627 write_lock(&entries_lock);
628 list_add(&e->list, &entries);
629 write_unlock(&entries_lock);
630
631 err = 0;
632out2:
633 dput(dentry);
634out:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800635 mutex_unlock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 dput(root);
637
638 if (err) {
639 kfree(e);
640 return -EINVAL;
641 }
642 return count;
643}
644
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800645static const struct file_operations bm_register_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 .write = bm_register_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200647 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648};
649
650/* /status */
651
652static ssize_t
653bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
654{
Qinghuang Feng87113e82009-01-06 14:41:38 -0800655 char *s = enabled ? "enabled\n" : "disabled\n";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656
Akinobu Mita92f4c702007-05-09 02:33:32 -0700657 return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658}
659
660static ssize_t bm_status_write(struct file * file, const char __user * buffer,
661 size_t count, loff_t *ppos)
662{
663 int res = parse_command(buffer, count);
664 struct dentry *root;
665
666 switch (res) {
667 case 1: enabled = 0; break;
668 case 2: enabled = 1; break;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800669 case 3: root = dget(file->f_path.mnt->mnt_sb->s_root);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800670 mutex_lock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
672 while (!list_empty(&entries))
673 kill_node(list_entry(entries.next, Node, list));
674
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800675 mutex_unlock(&root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 dput(root);
677 default: return res;
678 }
679 return count;
680}
681
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800682static const struct file_operations bm_status_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 .read = bm_status_read,
684 .write = bm_status_write,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200685 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686};
687
688/* Superblock handling */
689
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800690static const struct super_operations s_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 .statfs = simple_statfs,
Al Virob57922d2010-06-07 14:34:48 -0400692 .evict_inode = bm_evict_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693};
694
695static int bm_fill_super(struct super_block * sb, void * data, int silent)
696{
697 static struct tree_descr bm_files[] = {
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700698 [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
699 [3] = {"register", &bm_register_operations, S_IWUSR},
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 /* last one */ {""}
701 };
702 int err = simple_fill_super(sb, 0x42494e4d, bm_files);
703 if (!err)
704 sb->s_op = &s_ops;
705 return err;
706}
707
Al Virofc14f2f2010-07-25 01:48:30 +0400708static struct dentry *bm_mount(struct file_system_type *fs_type,
709 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710{
Al Virofc14f2f2010-07-25 01:48:30 +0400711 return mount_single(fs_type, flags, data, bm_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712}
713
714static struct linux_binfmt misc_format = {
715 .module = THIS_MODULE,
716 .load_binary = load_misc_binary,
717};
718
719static struct file_system_type bm_fs_type = {
720 .owner = THIS_MODULE,
721 .name = "binfmt_misc",
Al Virofc14f2f2010-07-25 01:48:30 +0400722 .mount = bm_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 .kill_sb = kill_litter_super,
724};
725
726static int __init init_misc_binfmt(void)
727{
728 int err = register_filesystem(&bm_fs_type);
729 if (!err) {
Jan Semberaee3aebd2010-09-09 16:37:54 -0700730 err = insert_binfmt(&misc_format);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 if (err)
732 unregister_filesystem(&bm_fs_type);
733 }
734 return err;
735}
736
737static void __exit exit_misc_binfmt(void)
738{
739 unregister_binfmt(&misc_format);
740 unregister_filesystem(&bm_fs_type);
741}
742
743core_initcall(init_misc_binfmt);
744module_exit(exit_misc_binfmt);
745MODULE_LICENSE("GPL");