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Commit | Line | Data |
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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 | ||
3a2e7f47 PE |
118 | retval = -ENOEXEC; |
119 | if (bprm->misc_bang) | |
120 | goto _ret; | |
121 | ||
122 | bprm->misc_bang = 1; | |
123 | ||
1da177e4 LT |
124 | /* to keep locking time low, we copy the interpreter string */ |
125 | read_lock(&entries_lock); | |
126 | fmt = check_file(bprm); | |
127 | if (fmt) | |
128 | strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); | |
129 | read_unlock(&entries_lock); | |
130 | if (!fmt) | |
131 | goto _ret; | |
132 | ||
133 | if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { | |
b6a2fea3 OW |
134 | retval = remove_arg_zero(bprm); |
135 | if (retval) | |
136 | goto _ret; | |
1da177e4 LT |
137 | } |
138 | ||
139 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { | |
140 | ||
1da177e4 LT |
141 | /* if the binary should be opened on behalf of the |
142 | * interpreter than keep it open and assign descriptor | |
143 | * to it */ | |
144 | fd_binary = get_unused_fd(); | |
145 | if (fd_binary < 0) { | |
146 | retval = fd_binary; | |
fd8328be | 147 | goto _ret; |
1da177e4 LT |
148 | } |
149 | fd_install(fd_binary, bprm->file); | |
150 | ||
151 | /* if the binary is not readable than enforce mm->dumpable=0 | |
152 | regardless of the interpreter's permissions */ | |
8c744fb8 | 153 | if (file_permission(bprm->file, MAY_READ)) |
1da177e4 LT |
154 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
155 | ||
156 | allow_write_access(bprm->file); | |
157 | bprm->file = NULL; | |
158 | ||
159 | /* mark the bprm that fd should be passed to interp */ | |
160 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; | |
161 | bprm->interp_data = fd_binary; | |
162 | ||
163 | } else { | |
164 | allow_write_access(bprm->file); | |
165 | fput(bprm->file); | |
166 | bprm->file = NULL; | |
167 | } | |
168 | /* make argv[1] be the path to the binary */ | |
169 | retval = copy_strings_kernel (1, &bprm->interp, bprm); | |
170 | if (retval < 0) | |
171 | goto _error; | |
172 | bprm->argc++; | |
173 | ||
174 | /* add the interp as argv[0] */ | |
175 | retval = copy_strings_kernel (1, &iname_addr, bprm); | |
176 | if (retval < 0) | |
177 | goto _error; | |
178 | bprm->argc ++; | |
179 | ||
180 | bprm->interp = iname; /* for binfmt_script */ | |
181 | ||
182 | interp_file = open_exec (iname); | |
183 | retval = PTR_ERR (interp_file); | |
184 | if (IS_ERR (interp_file)) | |
185 | goto _error; | |
186 | ||
187 | bprm->file = interp_file; | |
188 | if (fmt->flags & MISC_FMT_CREDENTIALS) { | |
189 | /* | |
190 | * No need to call prepare_binprm(), it's already been | |
191 | * done. bprm->buf is stale, update from interp_file. | |
192 | */ | |
193 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
194 | retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
195 | } else | |
196 | retval = prepare_binprm (bprm); | |
197 | ||
198 | if (retval < 0) | |
199 | goto _error; | |
200 | ||
201 | retval = search_binary_handler (bprm, regs); | |
202 | if (retval < 0) | |
203 | goto _error; | |
204 | ||
1da177e4 LT |
205 | _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; | |
1da177e4 LT |
212 | 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 | */ | |
223 | static 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 | ||
239 | static 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 | ||
858119e1 | 257 | static char * check_special_flags (char * sfs, Node * e) |
1da177e4 LT |
258 | { |
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 | */ | |
292 | static 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; | |
5cbded58 | 306 | e = kmalloc(memsize, GFP_USER); |
1da177e4 LT |
307 | 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 | ||
398 | out: | |
399 | return ERR_PTR(err); | |
400 | ||
401 | Efault: | |
402 | kfree(e); | |
403 | return ERR_PTR(-EFAULT); | |
404 | Einval: | |
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 | */ | |
413 | static 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 | ||
436 | static 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 | ||
492 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
493 | { | |
494 | struct inode * inode = new_inode(sb); | |
495 | ||
496 | if (inode) { | |
497 | inode->i_mode = mode; | |
498 | inode->i_uid = 0; | |
499 | inode->i_gid = 0; | |
1da177e4 LT |
500 | inode->i_blocks = 0; |
501 | inode->i_atime = inode->i_mtime = inode->i_ctime = | |
502 | current_fs_time(inode->i_sb); | |
503 | } | |
504 | return inode; | |
505 | } | |
506 | ||
507 | static void bm_clear_inode(struct inode *inode) | |
508 | { | |
8e18e294 | 509 | kfree(inode->i_private); |
1da177e4 LT |
510 | } |
511 | ||
512 | static void kill_node(Node *e) | |
513 | { | |
514 | struct dentry *dentry; | |
515 | ||
516 | write_lock(&entries_lock); | |
517 | dentry = e->dentry; | |
518 | if (dentry) { | |
519 | list_del_init(&e->list); | |
520 | e->dentry = NULL; | |
521 | } | |
522 | write_unlock(&entries_lock); | |
523 | ||
524 | if (dentry) { | |
525 | dentry->d_inode->i_nlink--; | |
526 | d_drop(dentry); | |
527 | dput(dentry); | |
528 | simple_release_fs(&bm_mnt, &entry_count); | |
529 | } | |
530 | } | |
531 | ||
532 | /* /<entry> */ | |
533 | ||
534 | static ssize_t | |
535 | bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos) | |
536 | { | |
0f7fc9e4 | 537 | Node *e = file->f_path.dentry->d_inode->i_private; |
1da177e4 LT |
538 | loff_t pos = *ppos; |
539 | ssize_t res; | |
540 | char *page; | |
541 | int len; | |
542 | ||
543 | if (!(page = (char*) __get_free_page(GFP_KERNEL))) | |
544 | return -ENOMEM; | |
545 | ||
546 | entry_status(e, page); | |
547 | len = strlen(page); | |
548 | ||
549 | res = -EINVAL; | |
550 | if (pos < 0) | |
551 | goto out; | |
552 | res = 0; | |
553 | if (pos >= len) | |
554 | goto out; | |
555 | if (len < pos + nbytes) | |
556 | nbytes = len - pos; | |
557 | res = -EFAULT; | |
558 | if (copy_to_user(buf, page + pos, nbytes)) | |
559 | goto out; | |
560 | *ppos = pos + nbytes; | |
561 | res = nbytes; | |
562 | out: | |
563 | free_page((unsigned long) page); | |
564 | return res; | |
565 | } | |
566 | ||
567 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
568 | size_t count, loff_t *ppos) | |
569 | { | |
570 | struct dentry *root; | |
0f7fc9e4 | 571 | Node *e = file->f_path.dentry->d_inode->i_private; |
1da177e4 LT |
572 | int res = parse_command(buffer, count); |
573 | ||
574 | switch (res) { | |
575 | case 1: clear_bit(Enabled, &e->flags); | |
576 | break; | |
577 | case 2: set_bit(Enabled, &e->flags); | |
578 | break; | |
0f7fc9e4 | 579 | case 3: root = dget(file->f_path.mnt->mnt_sb->s_root); |
1b1dcc1b | 580 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
581 | |
582 | kill_node(e); | |
583 | ||
1b1dcc1b | 584 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
585 | dput(root); |
586 | break; | |
587 | default: return res; | |
588 | } | |
589 | return count; | |
590 | } | |
591 | ||
4b6f5d20 | 592 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
593 | .read = bm_entry_read, |
594 | .write = bm_entry_write, | |
595 | }; | |
596 | ||
597 | /* /register */ | |
598 | ||
599 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
600 | size_t count, loff_t *ppos) | |
601 | { | |
602 | Node *e; | |
603 | struct inode *inode; | |
604 | struct dentry *root, *dentry; | |
0f7fc9e4 | 605 | struct super_block *sb = file->f_path.mnt->mnt_sb; |
1da177e4 LT |
606 | int err = 0; |
607 | ||
608 | e = create_entry(buffer, count); | |
609 | ||
610 | if (IS_ERR(e)) | |
611 | return PTR_ERR(e); | |
612 | ||
613 | root = dget(sb->s_root); | |
1b1dcc1b | 614 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
615 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
616 | err = PTR_ERR(dentry); | |
617 | if (IS_ERR(dentry)) | |
618 | goto out; | |
619 | ||
620 | err = -EEXIST; | |
621 | if (dentry->d_inode) | |
622 | goto out2; | |
623 | ||
624 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
625 | ||
626 | err = -ENOMEM; | |
627 | if (!inode) | |
628 | goto out2; | |
629 | ||
1f5ce9e9 | 630 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
631 | if (err) { |
632 | iput(inode); | |
633 | inode = NULL; | |
634 | goto out2; | |
635 | } | |
636 | ||
637 | e->dentry = dget(dentry); | |
8e18e294 | 638 | inode->i_private = e; |
1da177e4 LT |
639 | inode->i_fop = &bm_entry_operations; |
640 | ||
641 | d_instantiate(dentry, inode); | |
642 | write_lock(&entries_lock); | |
643 | list_add(&e->list, &entries); | |
644 | write_unlock(&entries_lock); | |
645 | ||
646 | err = 0; | |
647 | out2: | |
648 | dput(dentry); | |
649 | out: | |
1b1dcc1b | 650 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
651 | dput(root); |
652 | ||
653 | if (err) { | |
654 | kfree(e); | |
655 | return -EINVAL; | |
656 | } | |
657 | return count; | |
658 | } | |
659 | ||
4b6f5d20 | 660 | static const struct file_operations bm_register_operations = { |
1da177e4 LT |
661 | .write = bm_register_write, |
662 | }; | |
663 | ||
664 | /* /status */ | |
665 | ||
666 | static ssize_t | |
667 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
668 | { | |
669 | char *s = enabled ? "enabled" : "disabled"; | |
1da177e4 | 670 | |
92f4c701 | 671 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
672 | } |
673 | ||
674 | static ssize_t bm_status_write(struct file * file, const char __user * buffer, | |
675 | size_t count, loff_t *ppos) | |
676 | { | |
677 | int res = parse_command(buffer, count); | |
678 | struct dentry *root; | |
679 | ||
680 | switch (res) { | |
681 | case 1: enabled = 0; break; | |
682 | case 2: enabled = 1; break; | |
0f7fc9e4 | 683 | case 3: root = dget(file->f_path.mnt->mnt_sb->s_root); |
1b1dcc1b | 684 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
685 | |
686 | while (!list_empty(&entries)) | |
687 | kill_node(list_entry(entries.next, Node, list)); | |
688 | ||
1b1dcc1b | 689 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
690 | dput(root); |
691 | default: return res; | |
692 | } | |
693 | return count; | |
694 | } | |
695 | ||
4b6f5d20 | 696 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
697 | .read = bm_status_read, |
698 | .write = bm_status_write, | |
699 | }; | |
700 | ||
701 | /* Superblock handling */ | |
702 | ||
ee9b6d61 | 703 | static const struct super_operations s_ops = { |
1da177e4 LT |
704 | .statfs = simple_statfs, |
705 | .clear_inode = bm_clear_inode, | |
706 | }; | |
707 | ||
708 | static int bm_fill_super(struct super_block * sb, void * data, int silent) | |
709 | { | |
710 | static struct tree_descr bm_files[] = { | |
1a1c9bb4 JL |
711 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
712 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
713 | /* last one */ {""} |
714 | }; | |
715 | int err = simple_fill_super(sb, 0x42494e4d, bm_files); | |
716 | if (!err) | |
717 | sb->s_op = &s_ops; | |
718 | return err; | |
719 | } | |
720 | ||
454e2398 DH |
721 | static int bm_get_sb(struct file_system_type *fs_type, |
722 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 723 | { |
454e2398 | 724 | return get_sb_single(fs_type, flags, data, bm_fill_super, mnt); |
1da177e4 LT |
725 | } |
726 | ||
727 | static struct linux_binfmt misc_format = { | |
728 | .module = THIS_MODULE, | |
729 | .load_binary = load_misc_binary, | |
730 | }; | |
731 | ||
732 | static struct file_system_type bm_fs_type = { | |
733 | .owner = THIS_MODULE, | |
734 | .name = "binfmt_misc", | |
735 | .get_sb = bm_get_sb, | |
736 | .kill_sb = kill_litter_super, | |
737 | }; | |
738 | ||
739 | static int __init init_misc_binfmt(void) | |
740 | { | |
741 | int err = register_filesystem(&bm_fs_type); | |
742 | if (!err) { | |
743 | err = register_binfmt(&misc_format); | |
744 | if (err) | |
745 | unregister_filesystem(&bm_fs_type); | |
746 | } | |
747 | return err; | |
748 | } | |
749 | ||
750 | static void __exit exit_misc_binfmt(void) | |
751 | { | |
752 | unregister_binfmt(&misc_format); | |
753 | unregister_filesystem(&bm_fs_type); | |
754 | } | |
755 | ||
756 | core_initcall(init_misc_binfmt); | |
757 | module_exit(exit_misc_binfmt); | |
758 | MODULE_LICENSE("GPL"); |