Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * binfmt_misc.c | |
3 | * | |
96de0e25 | 4 | * Copyright (C) 1997 Richard Günther |
1da177e4 LT |
5 | * |
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> | |
e8edc6e0 | 21 | #include <linux/sched.h> |
b502bd11 | 22 | #include <linux/magic.h> |
1da177e4 LT |
23 | #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> | |
6e2c10a1 | 31 | #include <linux/fs.h> |
1da177e4 LT |
32 | |
33 | #include <asm/uaccess.h> | |
34 | ||
35 | enum { | |
36 | VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ | |
37 | }; | |
38 | ||
39 | static LIST_HEAD(entries); | |
40 | static int enabled = 1; | |
41 | ||
42 | enum {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 | ||
47 | typedef 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 | ||
59 | static DEFINE_RWLOCK(entries_lock); | |
1f5ce9e9 | 60 | static struct file_system_type bm_fs_type; |
1da177e4 LT |
61 | static struct vfsmount *bm_mnt; |
62 | static 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 | */ | |
69 | static 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 | */ | |
71613c3b | 107 | static int load_misc_binary(struct linux_binprm *bprm) |
1da177e4 LT |
108 | { |
109 | Node *fmt; | |
110 | struct file * interp_file = NULL; | |
111 | char iname[BINPRM_BUF_SIZE]; | |
d7627467 | 112 | const char *iname_addr = iname; |
1da177e4 LT |
113 | int retval; |
114 | int fd_binary = -1; | |
1da177e4 LT |
115 | |
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)) { | |
b6a2fea3 OW |
130 | retval = remove_arg_zero(bprm); |
131 | if (retval) | |
132 | goto _ret; | |
1da177e4 LT |
133 | } |
134 | ||
135 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { | |
136 | ||
1da177e4 LT |
137 | /* 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; | |
fd8328be | 143 | goto _ret; |
1da177e4 LT |
144 | } |
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 */ | |
1b5d783c | 149 | would_dump(bprm, bprm->file); |
1da177e4 LT |
150 | |
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 | ||
175 | bprm->interp = iname; /* for binfmt_script */ | |
176 | ||
177 | interp_file = open_exec (iname); | |
178 | retval = PTR_ERR (interp_file); | |
179 | if (IS_ERR (interp_file)) | |
180 | goto _error; | |
181 | ||
182 | bprm->file = interp_file; | |
183 | if (fmt->flags & MISC_FMT_CREDENTIALS) { | |
184 | /* | |
185 | * No need to call prepare_binprm(), it's already been | |
186 | * done. bprm->buf is stale, update from interp_file. | |
187 | */ | |
188 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
189 | retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
190 | } else | |
191 | retval = prepare_binprm (bprm); | |
192 | ||
193 | if (retval < 0) | |
194 | goto _error; | |
195 | ||
3c456bfc | 196 | retval = search_binary_handler(bprm); |
1da177e4 LT |
197 | if (retval < 0) |
198 | goto _error; | |
199 | ||
1da177e4 LT |
200 | _ret: |
201 | return retval; | |
202 | _error: | |
203 | if (fd_binary > 0) | |
204 | sys_close(fd_binary); | |
205 | bprm->interp_flags = 0; | |
206 | bprm->interp_data = 0; | |
1da177e4 LT |
207 | goto _ret; |
208 | } | |
209 | ||
210 | /* Command parsers */ | |
211 | ||
212 | /* | |
213 | * parses and copies one argument enclosed in del from *sp to *dp, | |
214 | * recognising the \x special. | |
215 | * returns pointer to the copied argument or NULL in case of an | |
216 | * error (and sets err) or null argument length. | |
217 | */ | |
218 | static char *scanarg(char *s, char del) | |
219 | { | |
220 | char c; | |
221 | ||
222 | while ((c = *s++) != del) { | |
223 | if (c == '\\' && *s == 'x') { | |
224 | s++; | |
225 | if (!isxdigit(*s++)) | |
226 | return NULL; | |
227 | if (!isxdigit(*s++)) | |
228 | return NULL; | |
229 | } | |
230 | } | |
231 | return s; | |
232 | } | |
233 | ||
234 | static int unquote(char *from) | |
235 | { | |
236 | char c = 0, *s = from, *p = from; | |
237 | ||
238 | while ((c = *s++) != '\0') { | |
239 | if (c == '\\' && *s == 'x') { | |
240 | s++; | |
241 | c = toupper(*s++); | |
242 | *p = (c - (isdigit(c) ? '0' : 'A' - 10)) << 4; | |
243 | c = toupper(*s++); | |
244 | *p++ |= c - (isdigit(c) ? '0' : 'A' - 10); | |
245 | continue; | |
246 | } | |
247 | *p++ = c; | |
248 | } | |
249 | return p - from; | |
250 | } | |
251 | ||
858119e1 | 252 | static char * check_special_flags (char * sfs, Node * e) |
1da177e4 LT |
253 | { |
254 | char * p = sfs; | |
255 | int cont = 1; | |
256 | ||
257 | /* special flags */ | |
258 | while (cont) { | |
259 | switch (*p) { | |
260 | case 'P': | |
261 | p++; | |
262 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
263 | break; | |
264 | case 'O': | |
265 | p++; | |
266 | e->flags |= MISC_FMT_OPEN_BINARY; | |
267 | break; | |
268 | case 'C': | |
269 | p++; | |
270 | /* this flags also implies the | |
271 | open-binary flag */ | |
272 | e->flags |= (MISC_FMT_CREDENTIALS | | |
273 | MISC_FMT_OPEN_BINARY); | |
274 | break; | |
275 | default: | |
276 | cont = 0; | |
277 | } | |
278 | } | |
279 | ||
280 | return p; | |
281 | } | |
282 | /* | |
283 | * This registers a new binary format, it recognises the syntax | |
284 | * ':name:type:offset:magic:mask:interpreter:flags' | |
285 | * where the ':' is the IFS, that can be chosen with the first char | |
286 | */ | |
287 | static Node *create_entry(const char __user *buffer, size_t count) | |
288 | { | |
289 | Node *e; | |
290 | int memsize, err; | |
291 | char *buf, *p; | |
292 | char del; | |
293 | ||
294 | /* some sanity checks */ | |
295 | err = -EINVAL; | |
296 | if ((count < 11) || (count > 256)) | |
297 | goto out; | |
298 | ||
299 | err = -ENOMEM; | |
300 | memsize = sizeof(Node) + count + 8; | |
5cbded58 | 301 | e = kmalloc(memsize, GFP_USER); |
1da177e4 LT |
302 | if (!e) |
303 | goto out; | |
304 | ||
305 | p = buf = (char *)e + sizeof(Node); | |
306 | ||
307 | memset(e, 0, sizeof(Node)); | |
308 | if (copy_from_user(buf, buffer, count)) | |
309 | goto Efault; | |
310 | ||
311 | del = *p++; /* delimeter */ | |
312 | ||
313 | memset(buf+count, del, 8); | |
314 | ||
315 | e->name = p; | |
316 | p = strchr(p, del); | |
317 | if (!p) | |
318 | goto Einval; | |
319 | *p++ = '\0'; | |
320 | if (!e->name[0] || | |
321 | !strcmp(e->name, ".") || | |
322 | !strcmp(e->name, "..") || | |
323 | strchr(e->name, '/')) | |
324 | goto Einval; | |
325 | switch (*p++) { | |
326 | case 'E': e->flags = 1<<Enabled; break; | |
327 | case 'M': e->flags = (1<<Enabled) | (1<<Magic); break; | |
328 | default: goto Einval; | |
329 | } | |
330 | if (*p++ != del) | |
331 | goto Einval; | |
332 | if (test_bit(Magic, &e->flags)) { | |
333 | char *s = strchr(p, del); | |
334 | if (!s) | |
335 | goto Einval; | |
336 | *s++ = '\0'; | |
337 | e->offset = simple_strtoul(p, &p, 10); | |
338 | if (*p++) | |
339 | goto Einval; | |
340 | e->magic = p; | |
341 | p = scanarg(p, del); | |
342 | if (!p) | |
343 | goto Einval; | |
344 | p[-1] = '\0'; | |
345 | if (!e->magic[0]) | |
346 | goto Einval; | |
347 | e->mask = p; | |
348 | p = scanarg(p, del); | |
349 | if (!p) | |
350 | goto Einval; | |
351 | p[-1] = '\0'; | |
352 | if (!e->mask[0]) | |
353 | e->mask = NULL; | |
354 | e->size = unquote(e->magic); | |
355 | if (e->mask && unquote(e->mask) != e->size) | |
356 | goto Einval; | |
357 | if (e->size + e->offset > BINPRM_BUF_SIZE) | |
358 | goto Einval; | |
359 | } else { | |
360 | p = strchr(p, del); | |
361 | if (!p) | |
362 | goto Einval; | |
363 | *p++ = '\0'; | |
364 | e->magic = p; | |
365 | p = strchr(p, del); | |
366 | if (!p) | |
367 | goto Einval; | |
368 | *p++ = '\0'; | |
369 | if (!e->magic[0] || strchr(e->magic, '/')) | |
370 | goto Einval; | |
371 | p = strchr(p, del); | |
372 | if (!p) | |
373 | goto Einval; | |
374 | *p++ = '\0'; | |
375 | } | |
376 | e->interpreter = p; | |
377 | p = strchr(p, del); | |
378 | if (!p) | |
379 | goto Einval; | |
380 | *p++ = '\0'; | |
381 | if (!e->interpreter[0]) | |
382 | goto Einval; | |
383 | ||
384 | ||
385 | p = check_special_flags (p, e); | |
386 | ||
387 | if (*p == '\n') | |
388 | p++; | |
389 | if (p != buf + count) | |
390 | goto Einval; | |
391 | return e; | |
392 | ||
393 | out: | |
394 | return ERR_PTR(err); | |
395 | ||
396 | Efault: | |
397 | kfree(e); | |
398 | return ERR_PTR(-EFAULT); | |
399 | Einval: | |
400 | kfree(e); | |
401 | return ERR_PTR(-EINVAL); | |
402 | } | |
403 | ||
404 | /* | |
405 | * Set status of entry/binfmt_misc: | |
406 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
407 | */ | |
408 | static int parse_command(const char __user *buffer, size_t count) | |
409 | { | |
410 | char s[4]; | |
411 | ||
412 | if (!count) | |
413 | return 0; | |
414 | if (count > 3) | |
415 | return -EINVAL; | |
416 | if (copy_from_user(s, buffer, count)) | |
417 | return -EFAULT; | |
418 | if (s[count-1] == '\n') | |
419 | count--; | |
420 | if (count == 1 && s[0] == '0') | |
421 | return 1; | |
422 | if (count == 1 && s[0] == '1') | |
423 | return 2; | |
424 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
425 | return 3; | |
426 | return -EINVAL; | |
427 | } | |
428 | ||
429 | /* generic stuff */ | |
430 | ||
431 | static void entry_status(Node *e, char *page) | |
432 | { | |
433 | char *dp; | |
434 | char *status = "disabled"; | |
435 | const char * flags = "flags: "; | |
436 | ||
437 | if (test_bit(Enabled, &e->flags)) | |
438 | status = "enabled"; | |
439 | ||
440 | if (!VERBOSE_STATUS) { | |
441 | sprintf(page, "%s\n", status); | |
442 | return; | |
443 | } | |
444 | ||
445 | sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); | |
446 | dp = page + strlen(page); | |
447 | ||
448 | /* print the special flags */ | |
449 | sprintf (dp, "%s", flags); | |
450 | dp += strlen (flags); | |
451 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) { | |
452 | *dp ++ = 'P'; | |
453 | } | |
454 | if (e->flags & MISC_FMT_OPEN_BINARY) { | |
455 | *dp ++ = 'O'; | |
456 | } | |
457 | if (e->flags & MISC_FMT_CREDENTIALS) { | |
458 | *dp ++ = 'C'; | |
459 | } | |
460 | *dp ++ = '\n'; | |
461 | ||
462 | ||
463 | if (!test_bit(Magic, &e->flags)) { | |
464 | sprintf(dp, "extension .%s\n", e->magic); | |
465 | } else { | |
466 | int i; | |
467 | ||
468 | sprintf(dp, "offset %i\nmagic ", e->offset); | |
469 | dp = page + strlen(page); | |
470 | for (i = 0; i < e->size; i++) { | |
471 | sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); | |
472 | dp += 2; | |
473 | } | |
474 | if (e->mask) { | |
475 | sprintf(dp, "\nmask "); | |
476 | dp += 6; | |
477 | for (i = 0; i < e->size; i++) { | |
478 | sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); | |
479 | dp += 2; | |
480 | } | |
481 | } | |
482 | *dp++ = '\n'; | |
483 | *dp = '\0'; | |
484 | } | |
485 | } | |
486 | ||
487 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
488 | { | |
489 | struct inode * inode = new_inode(sb); | |
490 | ||
491 | if (inode) { | |
85fe4025 | 492 | inode->i_ino = get_next_ino(); |
1da177e4 | 493 | inode->i_mode = mode; |
1da177e4 LT |
494 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
495 | current_fs_time(inode->i_sb); | |
496 | } | |
497 | return inode; | |
498 | } | |
499 | ||
b57922d9 | 500 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 501 | { |
dbd5768f | 502 | clear_inode(inode); |
8e18e294 | 503 | kfree(inode->i_private); |
1da177e4 LT |
504 | } |
505 | ||
506 | static void kill_node(Node *e) | |
507 | { | |
508 | struct dentry *dentry; | |
509 | ||
510 | write_lock(&entries_lock); | |
511 | dentry = e->dentry; | |
512 | if (dentry) { | |
513 | list_del_init(&e->list); | |
514 | e->dentry = NULL; | |
515 | } | |
516 | write_unlock(&entries_lock); | |
517 | ||
518 | if (dentry) { | |
6d6b77f1 | 519 | drop_nlink(dentry->d_inode); |
1da177e4 LT |
520 | d_drop(dentry); |
521 | dput(dentry); | |
522 | simple_release_fs(&bm_mnt, &entry_count); | |
523 | } | |
524 | } | |
525 | ||
526 | /* /<entry> */ | |
527 | ||
528 | static ssize_t | |
529 | bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos) | |
530 | { | |
0f7fc9e4 | 531 | Node *e = file->f_path.dentry->d_inode->i_private; |
1da177e4 LT |
532 | ssize_t res; |
533 | char *page; | |
1da177e4 LT |
534 | |
535 | if (!(page = (char*) __get_free_page(GFP_KERNEL))) | |
536 | return -ENOMEM; | |
537 | ||
538 | entry_status(e, page); | |
1da177e4 | 539 | |
6e2c10a1 AM |
540 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
541 | ||
1da177e4 LT |
542 | free_page((unsigned long) page); |
543 | return res; | |
544 | } | |
545 | ||
546 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
547 | size_t count, loff_t *ppos) | |
548 | { | |
549 | struct dentry *root; | |
0f7fc9e4 | 550 | Node *e = file->f_path.dentry->d_inode->i_private; |
1da177e4 LT |
551 | int res = parse_command(buffer, count); |
552 | ||
553 | switch (res) { | |
554 | case 1: clear_bit(Enabled, &e->flags); | |
555 | break; | |
556 | case 2: set_bit(Enabled, &e->flags); | |
557 | break; | |
d8c9584e | 558 | case 3: root = dget(file->f_path.dentry->d_sb->s_root); |
1b1dcc1b | 559 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
560 | |
561 | kill_node(e); | |
562 | ||
1b1dcc1b | 563 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
564 | dput(root); |
565 | break; | |
566 | default: return res; | |
567 | } | |
568 | return count; | |
569 | } | |
570 | ||
4b6f5d20 | 571 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
572 | .read = bm_entry_read, |
573 | .write = bm_entry_write, | |
6038f373 | 574 | .llseek = default_llseek, |
1da177e4 LT |
575 | }; |
576 | ||
577 | /* /register */ | |
578 | ||
579 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
580 | size_t count, loff_t *ppos) | |
581 | { | |
582 | Node *e; | |
583 | struct inode *inode; | |
584 | struct dentry *root, *dentry; | |
d8c9584e | 585 | struct super_block *sb = file->f_path.dentry->d_sb; |
1da177e4 LT |
586 | int err = 0; |
587 | ||
588 | e = create_entry(buffer, count); | |
589 | ||
590 | if (IS_ERR(e)) | |
591 | return PTR_ERR(e); | |
592 | ||
593 | root = dget(sb->s_root); | |
1b1dcc1b | 594 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
595 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
596 | err = PTR_ERR(dentry); | |
597 | if (IS_ERR(dentry)) | |
598 | goto out; | |
599 | ||
600 | err = -EEXIST; | |
601 | if (dentry->d_inode) | |
602 | goto out2; | |
603 | ||
604 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
605 | ||
606 | err = -ENOMEM; | |
607 | if (!inode) | |
608 | goto out2; | |
609 | ||
1f5ce9e9 | 610 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
611 | if (err) { |
612 | iput(inode); | |
613 | inode = NULL; | |
614 | goto out2; | |
615 | } | |
616 | ||
617 | e->dentry = dget(dentry); | |
8e18e294 | 618 | inode->i_private = e; |
1da177e4 LT |
619 | inode->i_fop = &bm_entry_operations; |
620 | ||
621 | d_instantiate(dentry, inode); | |
622 | write_lock(&entries_lock); | |
623 | list_add(&e->list, &entries); | |
624 | write_unlock(&entries_lock); | |
625 | ||
626 | err = 0; | |
627 | out2: | |
628 | dput(dentry); | |
629 | out: | |
1b1dcc1b | 630 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
631 | dput(root); |
632 | ||
633 | if (err) { | |
634 | kfree(e); | |
635 | return -EINVAL; | |
636 | } | |
637 | return count; | |
638 | } | |
639 | ||
4b6f5d20 | 640 | static const struct file_operations bm_register_operations = { |
1da177e4 | 641 | .write = bm_register_write, |
6038f373 | 642 | .llseek = noop_llseek, |
1da177e4 LT |
643 | }; |
644 | ||
645 | /* /status */ | |
646 | ||
647 | static ssize_t | |
648 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
649 | { | |
87113e80 | 650 | char *s = enabled ? "enabled\n" : "disabled\n"; |
1da177e4 | 651 | |
92f4c701 | 652 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
653 | } |
654 | ||
655 | static ssize_t bm_status_write(struct file * file, const char __user * buffer, | |
656 | size_t count, loff_t *ppos) | |
657 | { | |
658 | int res = parse_command(buffer, count); | |
659 | struct dentry *root; | |
660 | ||
661 | switch (res) { | |
662 | case 1: enabled = 0; break; | |
663 | case 2: enabled = 1; break; | |
d8c9584e | 664 | case 3: root = dget(file->f_path.dentry->d_sb->s_root); |
1b1dcc1b | 665 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
666 | |
667 | while (!list_empty(&entries)) | |
668 | kill_node(list_entry(entries.next, Node, list)); | |
669 | ||
1b1dcc1b | 670 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
671 | dput(root); |
672 | default: return res; | |
673 | } | |
674 | return count; | |
675 | } | |
676 | ||
4b6f5d20 | 677 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
678 | .read = bm_status_read, |
679 | .write = bm_status_write, | |
6038f373 | 680 | .llseek = default_llseek, |
1da177e4 LT |
681 | }; |
682 | ||
683 | /* Superblock handling */ | |
684 | ||
ee9b6d61 | 685 | static const struct super_operations s_ops = { |
1da177e4 | 686 | .statfs = simple_statfs, |
b57922d9 | 687 | .evict_inode = bm_evict_inode, |
1da177e4 LT |
688 | }; |
689 | ||
690 | static int bm_fill_super(struct super_block * sb, void * data, int silent) | |
691 | { | |
692 | static struct tree_descr bm_files[] = { | |
1a1c9bb4 JL |
693 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
694 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
695 | /* last one */ {""} |
696 | }; | |
b502bd11 | 697 | int err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); |
1da177e4 LT |
698 | if (!err) |
699 | sb->s_op = &s_ops; | |
700 | return err; | |
701 | } | |
702 | ||
fc14f2fe AV |
703 | static struct dentry *bm_mount(struct file_system_type *fs_type, |
704 | int flags, const char *dev_name, void *data) | |
1da177e4 | 705 | { |
fc14f2fe | 706 | return mount_single(fs_type, flags, data, bm_fill_super); |
1da177e4 LT |
707 | } |
708 | ||
709 | static struct linux_binfmt misc_format = { | |
710 | .module = THIS_MODULE, | |
711 | .load_binary = load_misc_binary, | |
712 | }; | |
713 | ||
714 | static struct file_system_type bm_fs_type = { | |
715 | .owner = THIS_MODULE, | |
716 | .name = "binfmt_misc", | |
fc14f2fe | 717 | .mount = bm_mount, |
1da177e4 LT |
718 | .kill_sb = kill_litter_super, |
719 | }; | |
720 | ||
721 | static int __init init_misc_binfmt(void) | |
722 | { | |
723 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
724 | if (!err) |
725 | insert_binfmt(&misc_format); | |
1da177e4 LT |
726 | return err; |
727 | } | |
728 | ||
729 | static void __exit exit_misc_binfmt(void) | |
730 | { | |
731 | unregister_binfmt(&misc_format); | |
732 | unregister_filesystem(&bm_fs_type); | |
733 | } | |
734 | ||
735 | core_initcall(init_misc_binfmt); | |
736 | module_exit(exit_misc_binfmt); | |
737 | MODULE_LICENSE("GPL"); |