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> |
1da177e4 LT |
22 | #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> | |
30 | ||
31 | #include <asm/uaccess.h> | |
32 | ||
33 | enum { | |
34 | VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ | |
35 | }; | |
36 | ||
37 | static LIST_HEAD(entries); | |
38 | static int enabled = 1; | |
39 | ||
40 | enum {Enabled, Magic}; | |
41 | #define MISC_FMT_PRESERVE_ARGV0 (1<<31) | |
42 | #define MISC_FMT_OPEN_BINARY (1<<30) | |
43 | #define MISC_FMT_CREDENTIALS (1<<29) | |
44 | ||
45 | typedef struct { | |
46 | struct list_head list; | |
47 | unsigned long flags; /* type, status, etc. */ | |
48 | int offset; /* offset of magic */ | |
49 | int size; /* size of magic/mask */ | |
50 | char *magic; /* magic or filename extension */ | |
51 | char *mask; /* mask, NULL for exact match */ | |
52 | char *interpreter; /* filename of interpreter */ | |
53 | char *name; | |
54 | struct dentry *dentry; | |
55 | } Node; | |
56 | ||
57 | static DEFINE_RWLOCK(entries_lock); | |
1f5ce9e9 | 58 | static struct file_system_type bm_fs_type; |
1da177e4 LT |
59 | static struct vfsmount *bm_mnt; |
60 | static int entry_count; | |
61 | ||
62 | /* | |
63 | * Check if we support the binfmt | |
64 | * if we do, return the node, else NULL | |
65 | * locking is done in load_misc_binary | |
66 | */ | |
67 | static Node *check_file(struct linux_binprm *bprm) | |
68 | { | |
69 | char *p = strrchr(bprm->interp, '.'); | |
70 | struct list_head *l; | |
71 | ||
72 | list_for_each(l, &entries) { | |
73 | Node *e = list_entry(l, Node, list); | |
74 | char *s; | |
75 | int j; | |
76 | ||
77 | if (!test_bit(Enabled, &e->flags)) | |
78 | continue; | |
79 | ||
80 | if (!test_bit(Magic, &e->flags)) { | |
81 | if (p && !strcmp(e->magic, p + 1)) | |
82 | return e; | |
83 | continue; | |
84 | } | |
85 | ||
86 | s = bprm->buf + e->offset; | |
87 | if (e->mask) { | |
88 | for (j = 0; j < e->size; j++) | |
89 | if ((*s++ ^ e->magic[j]) & e->mask[j]) | |
90 | break; | |
91 | } else { | |
92 | for (j = 0; j < e->size; j++) | |
93 | if ((*s++ ^ e->magic[j])) | |
94 | break; | |
95 | } | |
96 | if (j == e->size) | |
97 | return e; | |
98 | } | |
99 | return NULL; | |
100 | } | |
101 | ||
102 | /* | |
103 | * the loader itself | |
104 | */ | |
105 | static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs) | |
106 | { | |
107 | Node *fmt; | |
108 | struct file * interp_file = NULL; | |
109 | char iname[BINPRM_BUF_SIZE]; | |
110 | char *iname_addr = iname; | |
111 | int retval; | |
112 | int fd_binary = -1; | |
1da177e4 LT |
113 | |
114 | retval = -ENOEXEC; | |
115 | if (!enabled) | |
116 | goto _ret; | |
117 | ||
118 | /* to keep locking time low, we copy the interpreter string */ | |
119 | read_lock(&entries_lock); | |
120 | fmt = check_file(bprm); | |
121 | if (fmt) | |
122 | strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); | |
123 | read_unlock(&entries_lock); | |
124 | if (!fmt) | |
125 | goto _ret; | |
126 | ||
127 | if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { | |
b6a2fea3 OW |
128 | retval = remove_arg_zero(bprm); |
129 | if (retval) | |
130 | goto _ret; | |
1da177e4 LT |
131 | } |
132 | ||
133 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { | |
134 | ||
1da177e4 LT |
135 | /* if the binary should be opened on behalf of the |
136 | * interpreter than keep it open and assign descriptor | |
137 | * to it */ | |
138 | fd_binary = get_unused_fd(); | |
139 | if (fd_binary < 0) { | |
140 | retval = fd_binary; | |
fd8328be | 141 | goto _ret; |
1da177e4 LT |
142 | } |
143 | fd_install(fd_binary, bprm->file); | |
144 | ||
145 | /* if the binary is not readable than enforce mm->dumpable=0 | |
146 | regardless of the interpreter's permissions */ | |
8c744fb8 | 147 | if (file_permission(bprm->file, MAY_READ)) |
1da177e4 LT |
148 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
149 | ||
150 | allow_write_access(bprm->file); | |
151 | bprm->file = NULL; | |
152 | ||
153 | /* mark the bprm that fd should be passed to interp */ | |
154 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; | |
155 | bprm->interp_data = fd_binary; | |
156 | ||
157 | } else { | |
158 | allow_write_access(bprm->file); | |
159 | fput(bprm->file); | |
160 | bprm->file = NULL; | |
161 | } | |
162 | /* make argv[1] be the path to the binary */ | |
163 | retval = copy_strings_kernel (1, &bprm->interp, bprm); | |
164 | if (retval < 0) | |
165 | goto _error; | |
166 | bprm->argc++; | |
167 | ||
168 | /* add the interp as argv[0] */ | |
169 | retval = copy_strings_kernel (1, &iname_addr, bprm); | |
170 | if (retval < 0) | |
171 | goto _error; | |
172 | bprm->argc ++; | |
173 | ||
174 | bprm->interp = iname; /* for binfmt_script */ | |
175 | ||
176 | interp_file = open_exec (iname); | |
177 | retval = PTR_ERR (interp_file); | |
178 | if (IS_ERR (interp_file)) | |
179 | goto _error; | |
180 | ||
181 | bprm->file = interp_file; | |
182 | if (fmt->flags & MISC_FMT_CREDENTIALS) { | |
183 | /* | |
184 | * No need to call prepare_binprm(), it's already been | |
185 | * done. bprm->buf is stale, update from interp_file. | |
186 | */ | |
187 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
188 | retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
189 | } else | |
190 | retval = prepare_binprm (bprm); | |
191 | ||
192 | if (retval < 0) | |
193 | goto _error; | |
194 | ||
195 | retval = search_binary_handler (bprm, regs); | |
196 | if (retval < 0) | |
197 | goto _error; | |
198 | ||
1da177e4 LT |
199 | _ret: |
200 | return retval; | |
201 | _error: | |
202 | if (fd_binary > 0) | |
203 | sys_close(fd_binary); | |
204 | bprm->interp_flags = 0; | |
205 | bprm->interp_data = 0; | |
1da177e4 LT |
206 | goto _ret; |
207 | } | |
208 | ||
209 | /* Command parsers */ | |
210 | ||
211 | /* | |
212 | * parses and copies one argument enclosed in del from *sp to *dp, | |
213 | * recognising the \x special. | |
214 | * returns pointer to the copied argument or NULL in case of an | |
215 | * error (and sets err) or null argument length. | |
216 | */ | |
217 | static char *scanarg(char *s, char del) | |
218 | { | |
219 | char c; | |
220 | ||
221 | while ((c = *s++) != del) { | |
222 | if (c == '\\' && *s == 'x') { | |
223 | s++; | |
224 | if (!isxdigit(*s++)) | |
225 | return NULL; | |
226 | if (!isxdigit(*s++)) | |
227 | return NULL; | |
228 | } | |
229 | } | |
230 | return s; | |
231 | } | |
232 | ||
233 | static int unquote(char *from) | |
234 | { | |
235 | char c = 0, *s = from, *p = from; | |
236 | ||
237 | while ((c = *s++) != '\0') { | |
238 | if (c == '\\' && *s == 'x') { | |
239 | s++; | |
240 | c = toupper(*s++); | |
241 | *p = (c - (isdigit(c) ? '0' : 'A' - 10)) << 4; | |
242 | c = toupper(*s++); | |
243 | *p++ |= c - (isdigit(c) ? '0' : 'A' - 10); | |
244 | continue; | |
245 | } | |
246 | *p++ = c; | |
247 | } | |
248 | return p - from; | |
249 | } | |
250 | ||
858119e1 | 251 | static char * check_special_flags (char * sfs, Node * e) |
1da177e4 LT |
252 | { |
253 | char * p = sfs; | |
254 | int cont = 1; | |
255 | ||
256 | /* special flags */ | |
257 | while (cont) { | |
258 | switch (*p) { | |
259 | case 'P': | |
260 | p++; | |
261 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
262 | break; | |
263 | case 'O': | |
264 | p++; | |
265 | e->flags |= MISC_FMT_OPEN_BINARY; | |
266 | break; | |
267 | case 'C': | |
268 | p++; | |
269 | /* this flags also implies the | |
270 | open-binary flag */ | |
271 | e->flags |= (MISC_FMT_CREDENTIALS | | |
272 | MISC_FMT_OPEN_BINARY); | |
273 | break; | |
274 | default: | |
275 | cont = 0; | |
276 | } | |
277 | } | |
278 | ||
279 | return p; | |
280 | } | |
281 | /* | |
282 | * This registers a new binary format, it recognises the syntax | |
283 | * ':name:type:offset:magic:mask:interpreter:flags' | |
284 | * where the ':' is the IFS, that can be chosen with the first char | |
285 | */ | |
286 | static Node *create_entry(const char __user *buffer, size_t count) | |
287 | { | |
288 | Node *e; | |
289 | int memsize, err; | |
290 | char *buf, *p; | |
291 | char del; | |
292 | ||
293 | /* some sanity checks */ | |
294 | err = -EINVAL; | |
295 | if ((count < 11) || (count > 256)) | |
296 | goto out; | |
297 | ||
298 | err = -ENOMEM; | |
299 | memsize = sizeof(Node) + count + 8; | |
5cbded58 | 300 | e = kmalloc(memsize, GFP_USER); |
1da177e4 LT |
301 | if (!e) |
302 | goto out; | |
303 | ||
304 | p = buf = (char *)e + sizeof(Node); | |
305 | ||
306 | memset(e, 0, sizeof(Node)); | |
307 | if (copy_from_user(buf, buffer, count)) | |
308 | goto Efault; | |
309 | ||
310 | del = *p++; /* delimeter */ | |
311 | ||
312 | memset(buf+count, del, 8); | |
313 | ||
314 | e->name = p; | |
315 | p = strchr(p, del); | |
316 | if (!p) | |
317 | goto Einval; | |
318 | *p++ = '\0'; | |
319 | if (!e->name[0] || | |
320 | !strcmp(e->name, ".") || | |
321 | !strcmp(e->name, "..") || | |
322 | strchr(e->name, '/')) | |
323 | goto Einval; | |
324 | switch (*p++) { | |
325 | case 'E': e->flags = 1<<Enabled; break; | |
326 | case 'M': e->flags = (1<<Enabled) | (1<<Magic); break; | |
327 | default: goto Einval; | |
328 | } | |
329 | if (*p++ != del) | |
330 | goto Einval; | |
331 | if (test_bit(Magic, &e->flags)) { | |
332 | char *s = strchr(p, del); | |
333 | if (!s) | |
334 | goto Einval; | |
335 | *s++ = '\0'; | |
336 | e->offset = simple_strtoul(p, &p, 10); | |
337 | if (*p++) | |
338 | goto Einval; | |
339 | e->magic = p; | |
340 | p = scanarg(p, del); | |
341 | if (!p) | |
342 | goto Einval; | |
343 | p[-1] = '\0'; | |
344 | if (!e->magic[0]) | |
345 | goto Einval; | |
346 | e->mask = p; | |
347 | p = scanarg(p, del); | |
348 | if (!p) | |
349 | goto Einval; | |
350 | p[-1] = '\0'; | |
351 | if (!e->mask[0]) | |
352 | e->mask = NULL; | |
353 | e->size = unquote(e->magic); | |
354 | if (e->mask && unquote(e->mask) != e->size) | |
355 | goto Einval; | |
356 | if (e->size + e->offset > BINPRM_BUF_SIZE) | |
357 | goto Einval; | |
358 | } else { | |
359 | p = strchr(p, del); | |
360 | if (!p) | |
361 | goto Einval; | |
362 | *p++ = '\0'; | |
363 | e->magic = p; | |
364 | p = strchr(p, del); | |
365 | if (!p) | |
366 | goto Einval; | |
367 | *p++ = '\0'; | |
368 | if (!e->magic[0] || strchr(e->magic, '/')) | |
369 | goto Einval; | |
370 | p = strchr(p, del); | |
371 | if (!p) | |
372 | goto Einval; | |
373 | *p++ = '\0'; | |
374 | } | |
375 | e->interpreter = p; | |
376 | p = strchr(p, del); | |
377 | if (!p) | |
378 | goto Einval; | |
379 | *p++ = '\0'; | |
380 | if (!e->interpreter[0]) | |
381 | goto Einval; | |
382 | ||
383 | ||
384 | p = check_special_flags (p, e); | |
385 | ||
386 | if (*p == '\n') | |
387 | p++; | |
388 | if (p != buf + count) | |
389 | goto Einval; | |
390 | return e; | |
391 | ||
392 | out: | |
393 | return ERR_PTR(err); | |
394 | ||
395 | Efault: | |
396 | kfree(e); | |
397 | return ERR_PTR(-EFAULT); | |
398 | Einval: | |
399 | kfree(e); | |
400 | return ERR_PTR(-EINVAL); | |
401 | } | |
402 | ||
403 | /* | |
404 | * Set status of entry/binfmt_misc: | |
405 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
406 | */ | |
407 | static int parse_command(const char __user *buffer, size_t count) | |
408 | { | |
409 | char s[4]; | |
410 | ||
411 | if (!count) | |
412 | return 0; | |
413 | if (count > 3) | |
414 | return -EINVAL; | |
415 | if (copy_from_user(s, buffer, count)) | |
416 | return -EFAULT; | |
417 | if (s[count-1] == '\n') | |
418 | count--; | |
419 | if (count == 1 && s[0] == '0') | |
420 | return 1; | |
421 | if (count == 1 && s[0] == '1') | |
422 | return 2; | |
423 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
424 | return 3; | |
425 | return -EINVAL; | |
426 | } | |
427 | ||
428 | /* generic stuff */ | |
429 | ||
430 | static void entry_status(Node *e, char *page) | |
431 | { | |
432 | char *dp; | |
433 | char *status = "disabled"; | |
434 | const char * flags = "flags: "; | |
435 | ||
436 | if (test_bit(Enabled, &e->flags)) | |
437 | status = "enabled"; | |
438 | ||
439 | if (!VERBOSE_STATUS) { | |
440 | sprintf(page, "%s\n", status); | |
441 | return; | |
442 | } | |
443 | ||
444 | sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); | |
445 | dp = page + strlen(page); | |
446 | ||
447 | /* print the special flags */ | |
448 | sprintf (dp, "%s", flags); | |
449 | dp += strlen (flags); | |
450 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) { | |
451 | *dp ++ = 'P'; | |
452 | } | |
453 | if (e->flags & MISC_FMT_OPEN_BINARY) { | |
454 | *dp ++ = 'O'; | |
455 | } | |
456 | if (e->flags & MISC_FMT_CREDENTIALS) { | |
457 | *dp ++ = 'C'; | |
458 | } | |
459 | *dp ++ = '\n'; | |
460 | ||
461 | ||
462 | if (!test_bit(Magic, &e->flags)) { | |
463 | sprintf(dp, "extension .%s\n", e->magic); | |
464 | } else { | |
465 | int i; | |
466 | ||
467 | sprintf(dp, "offset %i\nmagic ", e->offset); | |
468 | dp = page + strlen(page); | |
469 | for (i = 0; i < e->size; i++) { | |
470 | sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); | |
471 | dp += 2; | |
472 | } | |
473 | if (e->mask) { | |
474 | sprintf(dp, "\nmask "); | |
475 | dp += 6; | |
476 | for (i = 0; i < e->size; i++) { | |
477 | sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); | |
478 | dp += 2; | |
479 | } | |
480 | } | |
481 | *dp++ = '\n'; | |
482 | *dp = '\0'; | |
483 | } | |
484 | } | |
485 | ||
486 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
487 | { | |
488 | struct inode * inode = new_inode(sb); | |
489 | ||
490 | if (inode) { | |
491 | inode->i_mode = mode; | |
492 | inode->i_uid = 0; | |
493 | inode->i_gid = 0; | |
1da177e4 LT |
494 | inode->i_blocks = 0; |
495 | inode->i_atime = inode->i_mtime = inode->i_ctime = | |
496 | current_fs_time(inode->i_sb); | |
497 | } | |
498 | return inode; | |
499 | } | |
500 | ||
501 | static void bm_clear_inode(struct inode *inode) | |
502 | { | |
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) { | |
519 | dentry->d_inode->i_nlink--; | |
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 | loff_t pos = *ppos; |
533 | ssize_t res; | |
534 | char *page; | |
535 | int len; | |
536 | ||
537 | if (!(page = (char*) __get_free_page(GFP_KERNEL))) | |
538 | return -ENOMEM; | |
539 | ||
540 | entry_status(e, page); | |
541 | len = strlen(page); | |
542 | ||
543 | res = -EINVAL; | |
544 | if (pos < 0) | |
545 | goto out; | |
546 | res = 0; | |
547 | if (pos >= len) | |
548 | goto out; | |
549 | if (len < pos + nbytes) | |
550 | nbytes = len - pos; | |
551 | res = -EFAULT; | |
552 | if (copy_to_user(buf, page + pos, nbytes)) | |
553 | goto out; | |
554 | *ppos = pos + nbytes; | |
555 | res = nbytes; | |
556 | out: | |
557 | free_page((unsigned long) page); | |
558 | return res; | |
559 | } | |
560 | ||
561 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
562 | size_t count, loff_t *ppos) | |
563 | { | |
564 | struct dentry *root; | |
0f7fc9e4 | 565 | Node *e = file->f_path.dentry->d_inode->i_private; |
1da177e4 LT |
566 | int res = parse_command(buffer, count); |
567 | ||
568 | switch (res) { | |
569 | case 1: clear_bit(Enabled, &e->flags); | |
570 | break; | |
571 | case 2: set_bit(Enabled, &e->flags); | |
572 | break; | |
0f7fc9e4 | 573 | case 3: root = dget(file->f_path.mnt->mnt_sb->s_root); |
1b1dcc1b | 574 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
575 | |
576 | kill_node(e); | |
577 | ||
1b1dcc1b | 578 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
579 | dput(root); |
580 | break; | |
581 | default: return res; | |
582 | } | |
583 | return count; | |
584 | } | |
585 | ||
4b6f5d20 | 586 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
587 | .read = bm_entry_read, |
588 | .write = bm_entry_write, | |
589 | }; | |
590 | ||
591 | /* /register */ | |
592 | ||
593 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
594 | size_t count, loff_t *ppos) | |
595 | { | |
596 | Node *e; | |
597 | struct inode *inode; | |
598 | struct dentry *root, *dentry; | |
0f7fc9e4 | 599 | struct super_block *sb = file->f_path.mnt->mnt_sb; |
1da177e4 LT |
600 | int err = 0; |
601 | ||
602 | e = create_entry(buffer, count); | |
603 | ||
604 | if (IS_ERR(e)) | |
605 | return PTR_ERR(e); | |
606 | ||
607 | root = dget(sb->s_root); | |
1b1dcc1b | 608 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
609 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
610 | err = PTR_ERR(dentry); | |
611 | if (IS_ERR(dentry)) | |
612 | goto out; | |
613 | ||
614 | err = -EEXIST; | |
615 | if (dentry->d_inode) | |
616 | goto out2; | |
617 | ||
618 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
619 | ||
620 | err = -ENOMEM; | |
621 | if (!inode) | |
622 | goto out2; | |
623 | ||
1f5ce9e9 | 624 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
625 | if (err) { |
626 | iput(inode); | |
627 | inode = NULL; | |
628 | goto out2; | |
629 | } | |
630 | ||
631 | e->dentry = dget(dentry); | |
8e18e294 | 632 | inode->i_private = e; |
1da177e4 LT |
633 | inode->i_fop = &bm_entry_operations; |
634 | ||
635 | d_instantiate(dentry, inode); | |
636 | write_lock(&entries_lock); | |
637 | list_add(&e->list, &entries); | |
638 | write_unlock(&entries_lock); | |
639 | ||
640 | err = 0; | |
641 | out2: | |
642 | dput(dentry); | |
643 | out: | |
1b1dcc1b | 644 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
645 | dput(root); |
646 | ||
647 | if (err) { | |
648 | kfree(e); | |
649 | return -EINVAL; | |
650 | } | |
651 | return count; | |
652 | } | |
653 | ||
4b6f5d20 | 654 | static const struct file_operations bm_register_operations = { |
1da177e4 LT |
655 | .write = bm_register_write, |
656 | }; | |
657 | ||
658 | /* /status */ | |
659 | ||
660 | static ssize_t | |
661 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
662 | { | |
663 | char *s = enabled ? "enabled" : "disabled"; | |
1da177e4 | 664 | |
92f4c701 | 665 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
666 | } |
667 | ||
668 | static ssize_t bm_status_write(struct file * file, const char __user * buffer, | |
669 | size_t count, loff_t *ppos) | |
670 | { | |
671 | int res = parse_command(buffer, count); | |
672 | struct dentry *root; | |
673 | ||
674 | switch (res) { | |
675 | case 1: enabled = 0; break; | |
676 | case 2: enabled = 1; break; | |
0f7fc9e4 | 677 | case 3: root = dget(file->f_path.mnt->mnt_sb->s_root); |
1b1dcc1b | 678 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
679 | |
680 | while (!list_empty(&entries)) | |
681 | kill_node(list_entry(entries.next, Node, list)); | |
682 | ||
1b1dcc1b | 683 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
684 | dput(root); |
685 | default: return res; | |
686 | } | |
687 | return count; | |
688 | } | |
689 | ||
4b6f5d20 | 690 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
691 | .read = bm_status_read, |
692 | .write = bm_status_write, | |
693 | }; | |
694 | ||
695 | /* Superblock handling */ | |
696 | ||
ee9b6d61 | 697 | static const struct super_operations s_ops = { |
1da177e4 LT |
698 | .statfs = simple_statfs, |
699 | .clear_inode = bm_clear_inode, | |
700 | }; | |
701 | ||
702 | static int bm_fill_super(struct super_block * sb, void * data, int silent) | |
703 | { | |
704 | static struct tree_descr bm_files[] = { | |
1a1c9bb4 JL |
705 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
706 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
707 | /* last one */ {""} |
708 | }; | |
709 | int err = simple_fill_super(sb, 0x42494e4d, bm_files); | |
710 | if (!err) | |
711 | sb->s_op = &s_ops; | |
712 | return err; | |
713 | } | |
714 | ||
454e2398 DH |
715 | static int bm_get_sb(struct file_system_type *fs_type, |
716 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 717 | { |
454e2398 | 718 | return get_sb_single(fs_type, flags, data, bm_fill_super, mnt); |
1da177e4 LT |
719 | } |
720 | ||
721 | static struct linux_binfmt misc_format = { | |
722 | .module = THIS_MODULE, | |
723 | .load_binary = load_misc_binary, | |
724 | }; | |
725 | ||
726 | static struct file_system_type bm_fs_type = { | |
727 | .owner = THIS_MODULE, | |
728 | .name = "binfmt_misc", | |
729 | .get_sb = bm_get_sb, | |
730 | .kill_sb = kill_litter_super, | |
731 | }; | |
732 | ||
733 | static int __init init_misc_binfmt(void) | |
734 | { | |
735 | int err = register_filesystem(&bm_fs_type); | |
736 | if (!err) { | |
737 | err = register_binfmt(&misc_format); | |
738 | if (err) | |
739 | unregister_filesystem(&bm_fs_type); | |
740 | } | |
741 | return err; | |
742 | } | |
743 | ||
744 | static void __exit exit_misc_binfmt(void) | |
745 | { | |
746 | unregister_binfmt(&misc_format); | |
747 | unregister_filesystem(&bm_fs_type); | |
748 | } | |
749 | ||
750 | core_initcall(init_misc_binfmt); | |
751 | module_exit(exit_misc_binfmt); | |
752 | MODULE_LICENSE("GPL"); |