Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
e6084d4a | 2 | * binfmt_misc.c |
1da177e4 | 3 | * |
e6084d4a | 4 | * Copyright (C) 1997 Richard Günther |
1da177e4 | 5 | * |
e6084d4a MF |
6 | * binfmt_misc detects binaries via a magic or filename extension and invokes |
7 | * a specified wrapper. See Documentation/binfmt_misc.txt for more details. | |
1da177e4 LT |
8 | */ |
9 | ||
6b899c4e MF |
10 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
11 | ||
1da177e4 LT |
12 | #include <linux/module.h> |
13 | #include <linux/init.h> | |
e8edc6e0 | 14 | #include <linux/sched.h> |
b502bd11 | 15 | #include <linux/magic.h> |
1da177e4 LT |
16 | #include <linux/binfmts.h> |
17 | #include <linux/slab.h> | |
18 | #include <linux/ctype.h> | |
8d82e180 | 19 | #include <linux/string_helpers.h> |
1da177e4 LT |
20 | #include <linux/file.h> |
21 | #include <linux/pagemap.h> | |
22 | #include <linux/namei.h> | |
23 | #include <linux/mount.h> | |
24 | #include <linux/syscalls.h> | |
6e2c10a1 | 25 | #include <linux/fs.h> |
6b899c4e | 26 | #include <linux/uaccess.h> |
1da177e4 | 27 | |
6b899c4e MF |
28 | #ifdef DEBUG |
29 | # define USE_DEBUG 1 | |
30 | #else | |
31 | # define USE_DEBUG 0 | |
32 | #endif | |
1da177e4 LT |
33 | |
34 | enum { | |
35 | VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ | |
36 | }; | |
37 | ||
38 | static LIST_HEAD(entries); | |
39 | static int enabled = 1; | |
40 | ||
41 | enum {Enabled, Magic}; | |
e6084d4a MF |
42 | #define MISC_FMT_PRESERVE_ARGV0 (1 << 31) |
43 | #define MISC_FMT_OPEN_BINARY (1 << 30) | |
44 | #define MISC_FMT_CREDENTIALS (1 << 29) | |
1da177e4 LT |
45 | |
46 | typedef 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 | ||
58 | static DEFINE_RWLOCK(entries_lock); | |
1f5ce9e9 | 59 | static struct file_system_type bm_fs_type; |
1da177e4 LT |
60 | static struct vfsmount *bm_mnt; |
61 | static int entry_count; | |
62 | ||
bbaecc08 MF |
63 | /* |
64 | * Max length of the register string. Determined by: | |
65 | * - 7 delimiters | |
66 | * - name: ~50 bytes | |
67 | * - type: 1 byte | |
68 | * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE) | |
69 | * - magic: 128 bytes (512 in escaped form) | |
70 | * - mask: 128 bytes (512 in escaped form) | |
71 | * - interp: ~50 bytes | |
72 | * - flags: 5 bytes | |
73 | * Round that up a bit, and then back off to hold the internal data | |
74 | * (like struct Node). | |
75 | */ | |
76 | #define MAX_REGISTER_LENGTH 1920 | |
77 | ||
78 | /* | |
1da177e4 LT |
79 | * Check if we support the binfmt |
80 | * if we do, return the node, else NULL | |
81 | * locking is done in load_misc_binary | |
82 | */ | |
83 | static Node *check_file(struct linux_binprm *bprm) | |
84 | { | |
85 | char *p = strrchr(bprm->interp, '.'); | |
86 | struct list_head *l; | |
87 | ||
6b899c4e | 88 | /* Walk all the registered handlers. */ |
1da177e4 LT |
89 | list_for_each(l, &entries) { |
90 | Node *e = list_entry(l, Node, list); | |
91 | char *s; | |
92 | int j; | |
93 | ||
6b899c4e | 94 | /* Make sure this one is currently enabled. */ |
1da177e4 LT |
95 | if (!test_bit(Enabled, &e->flags)) |
96 | continue; | |
97 | ||
6b899c4e | 98 | /* Do matching based on extension if applicable. */ |
1da177e4 LT |
99 | if (!test_bit(Magic, &e->flags)) { |
100 | if (p && !strcmp(e->magic, p + 1)) | |
101 | return e; | |
102 | continue; | |
103 | } | |
104 | ||
6b899c4e | 105 | /* Do matching based on magic & mask. */ |
1da177e4 LT |
106 | s = bprm->buf + e->offset; |
107 | if (e->mask) { | |
108 | for (j = 0; j < e->size; j++) | |
109 | if ((*s++ ^ e->magic[j]) & e->mask[j]) | |
110 | break; | |
111 | } else { | |
112 | for (j = 0; j < e->size; j++) | |
113 | if ((*s++ ^ e->magic[j])) | |
114 | break; | |
115 | } | |
116 | if (j == e->size) | |
117 | return e; | |
118 | } | |
119 | return NULL; | |
120 | } | |
121 | ||
122 | /* | |
123 | * the loader itself | |
124 | */ | |
71613c3b | 125 | static int load_misc_binary(struct linux_binprm *bprm) |
1da177e4 LT |
126 | { |
127 | Node *fmt; | |
e6084d4a | 128 | struct file *interp_file = NULL; |
1da177e4 | 129 | char iname[BINPRM_BUF_SIZE]; |
d7627467 | 130 | const char *iname_addr = iname; |
1da177e4 LT |
131 | int retval; |
132 | int fd_binary = -1; | |
1da177e4 LT |
133 | |
134 | retval = -ENOEXEC; | |
135 | if (!enabled) | |
e6084d4a | 136 | goto ret; |
1da177e4 LT |
137 | |
138 | /* to keep locking time low, we copy the interpreter string */ | |
139 | read_lock(&entries_lock); | |
140 | fmt = check_file(bprm); | |
141 | if (fmt) | |
142 | strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); | |
143 | read_unlock(&entries_lock); | |
144 | if (!fmt) | |
e6084d4a | 145 | goto ret; |
1da177e4 LT |
146 | |
147 | if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { | |
b6a2fea3 OW |
148 | retval = remove_arg_zero(bprm); |
149 | if (retval) | |
e6084d4a | 150 | goto ret; |
1da177e4 LT |
151 | } |
152 | ||
153 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { | |
154 | ||
1da177e4 LT |
155 | /* if the binary should be opened on behalf of the |
156 | * interpreter than keep it open and assign descriptor | |
e6084d4a MF |
157 | * to it |
158 | */ | |
c6cb898b | 159 | fd_binary = get_unused_fd_flags(0); |
e6084d4a MF |
160 | if (fd_binary < 0) { |
161 | retval = fd_binary; | |
162 | goto ret; | |
163 | } | |
164 | fd_install(fd_binary, bprm->file); | |
1da177e4 LT |
165 | |
166 | /* if the binary is not readable than enforce mm->dumpable=0 | |
167 | regardless of the interpreter's permissions */ | |
1b5d783c | 168 | would_dump(bprm, bprm->file); |
1da177e4 LT |
169 | |
170 | allow_write_access(bprm->file); | |
171 | bprm->file = NULL; | |
172 | ||
173 | /* mark the bprm that fd should be passed to interp */ | |
174 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; | |
175 | bprm->interp_data = fd_binary; | |
176 | ||
e6084d4a MF |
177 | } else { |
178 | allow_write_access(bprm->file); | |
179 | fput(bprm->file); | |
180 | bprm->file = NULL; | |
181 | } | |
1da177e4 | 182 | /* make argv[1] be the path to the binary */ |
e6084d4a | 183 | retval = copy_strings_kernel(1, &bprm->interp, bprm); |
1da177e4 | 184 | if (retval < 0) |
e6084d4a | 185 | goto error; |
1da177e4 LT |
186 | bprm->argc++; |
187 | ||
188 | /* add the interp as argv[0] */ | |
e6084d4a | 189 | retval = copy_strings_kernel(1, &iname_addr, bprm); |
1da177e4 | 190 | if (retval < 0) |
e6084d4a MF |
191 | goto error; |
192 | bprm->argc++; | |
1da177e4 | 193 | |
b66c5984 KC |
194 | /* Update interp in case binfmt_script needs it. */ |
195 | retval = bprm_change_interp(iname, bprm); | |
196 | if (retval < 0) | |
e6084d4a | 197 | goto error; |
1da177e4 | 198 | |
e6084d4a MF |
199 | interp_file = open_exec(iname); |
200 | retval = PTR_ERR(interp_file); | |
201 | if (IS_ERR(interp_file)) | |
202 | goto error; | |
1da177e4 LT |
203 | |
204 | bprm->file = interp_file; | |
205 | if (fmt->flags & MISC_FMT_CREDENTIALS) { | |
206 | /* | |
207 | * No need to call prepare_binprm(), it's already been | |
208 | * done. bprm->buf is stale, update from interp_file. | |
209 | */ | |
210 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
211 | retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
212 | } else | |
e6084d4a | 213 | retval = prepare_binprm(bprm); |
1da177e4 LT |
214 | |
215 | if (retval < 0) | |
e6084d4a | 216 | goto error; |
1da177e4 | 217 | |
3c456bfc | 218 | retval = search_binary_handler(bprm); |
1da177e4 | 219 | if (retval < 0) |
e6084d4a | 220 | goto error; |
1da177e4 | 221 | |
e6084d4a | 222 | ret: |
1da177e4 | 223 | return retval; |
e6084d4a | 224 | error: |
1da177e4 LT |
225 | if (fd_binary > 0) |
226 | sys_close(fd_binary); | |
227 | bprm->interp_flags = 0; | |
228 | bprm->interp_data = 0; | |
e6084d4a | 229 | goto ret; |
1da177e4 LT |
230 | } |
231 | ||
232 | /* Command parsers */ | |
233 | ||
234 | /* | |
235 | * parses and copies one argument enclosed in del from *sp to *dp, | |
236 | * recognising the \x special. | |
237 | * returns pointer to the copied argument or NULL in case of an | |
238 | * error (and sets err) or null argument length. | |
239 | */ | |
240 | static char *scanarg(char *s, char del) | |
241 | { | |
242 | char c; | |
243 | ||
244 | while ((c = *s++) != del) { | |
245 | if (c == '\\' && *s == 'x') { | |
246 | s++; | |
247 | if (!isxdigit(*s++)) | |
248 | return NULL; | |
249 | if (!isxdigit(*s++)) | |
250 | return NULL; | |
251 | } | |
252 | } | |
253 | return s; | |
254 | } | |
255 | ||
e6084d4a | 256 | static char *check_special_flags(char *sfs, Node *e) |
1da177e4 | 257 | { |
e6084d4a | 258 | char *p = sfs; |
1da177e4 LT |
259 | int cont = 1; |
260 | ||
261 | /* special flags */ | |
262 | while (cont) { | |
263 | switch (*p) { | |
e6084d4a MF |
264 | case 'P': |
265 | pr_debug("register: flag: P (preserve argv0)\n"); | |
266 | p++; | |
267 | e->flags |= MISC_FMT_PRESERVE_ARGV0; | |
268 | break; | |
269 | case 'O': | |
270 | pr_debug("register: flag: O (open binary)\n"); | |
271 | p++; | |
272 | e->flags |= MISC_FMT_OPEN_BINARY; | |
273 | break; | |
274 | case 'C': | |
275 | pr_debug("register: flag: C (preserve creds)\n"); | |
276 | p++; | |
277 | /* this flags also implies the | |
278 | open-binary flag */ | |
279 | e->flags |= (MISC_FMT_CREDENTIALS | | |
280 | MISC_FMT_OPEN_BINARY); | |
281 | break; | |
282 | default: | |
283 | cont = 0; | |
1da177e4 LT |
284 | } |
285 | } | |
286 | ||
287 | return p; | |
288 | } | |
e6084d4a | 289 | |
1da177e4 LT |
290 | /* |
291 | * This registers a new binary format, it recognises the syntax | |
292 | * ':name:type:offset:magic:mask:interpreter:flags' | |
293 | * where the ':' is the IFS, that can be chosen with the first char | |
294 | */ | |
295 | static Node *create_entry(const char __user *buffer, size_t count) | |
296 | { | |
297 | Node *e; | |
298 | int memsize, err; | |
299 | char *buf, *p; | |
300 | char del; | |
301 | ||
6b899c4e MF |
302 | pr_debug("register: received %zu bytes\n", count); |
303 | ||
1da177e4 LT |
304 | /* some sanity checks */ |
305 | err = -EINVAL; | |
bbaecc08 | 306 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
1da177e4 LT |
307 | goto out; |
308 | ||
309 | err = -ENOMEM; | |
310 | memsize = sizeof(Node) + count + 8; | |
f7e1ad1a | 311 | e = kmalloc(memsize, GFP_KERNEL); |
1da177e4 LT |
312 | if (!e) |
313 | goto out; | |
314 | ||
315 | p = buf = (char *)e + sizeof(Node); | |
316 | ||
317 | memset(e, 0, sizeof(Node)); | |
318 | if (copy_from_user(buf, buffer, count)) | |
e6084d4a | 319 | goto efault; |
1da177e4 LT |
320 | |
321 | del = *p++; /* delimeter */ | |
322 | ||
6b899c4e MF |
323 | pr_debug("register: delim: %#x {%c}\n", del, del); |
324 | ||
325 | /* Pad the buffer with the delim to simplify parsing below. */ | |
e6084d4a | 326 | memset(buf + count, del, 8); |
1da177e4 | 327 | |
6b899c4e | 328 | /* Parse the 'name' field. */ |
1da177e4 LT |
329 | e->name = p; |
330 | p = strchr(p, del); | |
331 | if (!p) | |
e6084d4a | 332 | goto einval; |
1da177e4 LT |
333 | *p++ = '\0'; |
334 | if (!e->name[0] || | |
335 | !strcmp(e->name, ".") || | |
336 | !strcmp(e->name, "..") || | |
337 | strchr(e->name, '/')) | |
e6084d4a | 338 | goto einval; |
6b899c4e MF |
339 | |
340 | pr_debug("register: name: {%s}\n", e->name); | |
341 | ||
342 | /* Parse the 'type' field. */ | |
1da177e4 | 343 | switch (*p++) { |
6b899c4e MF |
344 | case 'E': |
345 | pr_debug("register: type: E (extension)\n"); | |
346 | e->flags = 1 << Enabled; | |
347 | break; | |
348 | case 'M': | |
349 | pr_debug("register: type: M (magic)\n"); | |
350 | e->flags = (1 << Enabled) | (1 << Magic); | |
351 | break; | |
352 | default: | |
e6084d4a | 353 | goto einval; |
1da177e4 LT |
354 | } |
355 | if (*p++ != del) | |
e6084d4a | 356 | goto einval; |
6b899c4e | 357 | |
1da177e4 | 358 | if (test_bit(Magic, &e->flags)) { |
6b899c4e MF |
359 | /* Handle the 'M' (magic) format. */ |
360 | char *s; | |
361 | ||
362 | /* Parse the 'offset' field. */ | |
363 | s = strchr(p, del); | |
1da177e4 | 364 | if (!s) |
e6084d4a | 365 | goto einval; |
1da177e4 LT |
366 | *s++ = '\0'; |
367 | e->offset = simple_strtoul(p, &p, 10); | |
368 | if (*p++) | |
e6084d4a | 369 | goto einval; |
6b899c4e MF |
370 | pr_debug("register: offset: %#x\n", e->offset); |
371 | ||
372 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
373 | e->magic = p; |
374 | p = scanarg(p, del); | |
375 | if (!p) | |
e6084d4a | 376 | goto einval; |
1da177e4 | 377 | p[-1] = '\0'; |
6b899c4e | 378 | if (p == e->magic) |
e6084d4a | 379 | goto einval; |
6b899c4e MF |
380 | if (USE_DEBUG) |
381 | print_hex_dump_bytes( | |
382 | KBUILD_MODNAME ": register: magic[raw]: ", | |
383 | DUMP_PREFIX_NONE, e->magic, p - e->magic); | |
384 | ||
385 | /* Parse the 'mask' field. */ | |
1da177e4 LT |
386 | e->mask = p; |
387 | p = scanarg(p, del); | |
388 | if (!p) | |
e6084d4a | 389 | goto einval; |
1da177e4 | 390 | p[-1] = '\0'; |
6b899c4e | 391 | if (p == e->mask) { |
1da177e4 | 392 | e->mask = NULL; |
6b899c4e MF |
393 | pr_debug("register: mask[raw]: none\n"); |
394 | } else if (USE_DEBUG) | |
395 | print_hex_dump_bytes( | |
396 | KBUILD_MODNAME ": register: mask[raw]: ", | |
397 | DUMP_PREFIX_NONE, e->mask, p - e->mask); | |
398 | ||
399 | /* | |
400 | * Decode the magic & mask fields. | |
401 | * Note: while we might have accepted embedded NUL bytes from | |
402 | * above, the unescape helpers here will stop at the first one | |
403 | * it encounters. | |
404 | */ | |
8d82e180 AS |
405 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
406 | if (e->mask && | |
407 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) | |
e6084d4a | 408 | goto einval; |
1da177e4 | 409 | if (e->size + e->offset > BINPRM_BUF_SIZE) |
e6084d4a | 410 | goto einval; |
6b899c4e MF |
411 | pr_debug("register: magic/mask length: %i\n", e->size); |
412 | if (USE_DEBUG) { | |
413 | print_hex_dump_bytes( | |
414 | KBUILD_MODNAME ": register: magic[decoded]: ", | |
415 | DUMP_PREFIX_NONE, e->magic, e->size); | |
416 | ||
417 | if (e->mask) { | |
418 | int i; | |
f7e1ad1a | 419 | char *masked = kmalloc(e->size, GFP_KERNEL); |
6b899c4e MF |
420 | |
421 | print_hex_dump_bytes( | |
422 | KBUILD_MODNAME ": register: mask[decoded]: ", | |
423 | DUMP_PREFIX_NONE, e->mask, e->size); | |
424 | ||
425 | if (masked) { | |
426 | for (i = 0; i < e->size; ++i) | |
427 | masked[i] = e->magic[i] & e->mask[i]; | |
428 | print_hex_dump_bytes( | |
429 | KBUILD_MODNAME ": register: magic[masked]: ", | |
430 | DUMP_PREFIX_NONE, masked, e->size); | |
431 | ||
432 | kfree(masked); | |
433 | } | |
434 | } | |
435 | } | |
1da177e4 | 436 | } else { |
6b899c4e MF |
437 | /* Handle the 'E' (extension) format. */ |
438 | ||
439 | /* Skip the 'offset' field. */ | |
1da177e4 LT |
440 | p = strchr(p, del); |
441 | if (!p) | |
e6084d4a | 442 | goto einval; |
1da177e4 | 443 | *p++ = '\0'; |
6b899c4e MF |
444 | |
445 | /* Parse the 'magic' field. */ | |
1da177e4 LT |
446 | e->magic = p; |
447 | p = strchr(p, del); | |
448 | if (!p) | |
e6084d4a | 449 | goto einval; |
1da177e4 LT |
450 | *p++ = '\0'; |
451 | if (!e->magic[0] || strchr(e->magic, '/')) | |
e6084d4a | 452 | goto einval; |
6b899c4e MF |
453 | pr_debug("register: extension: {%s}\n", e->magic); |
454 | ||
455 | /* Skip the 'mask' field. */ | |
1da177e4 LT |
456 | p = strchr(p, del); |
457 | if (!p) | |
e6084d4a | 458 | goto einval; |
1da177e4 LT |
459 | *p++ = '\0'; |
460 | } | |
6b899c4e MF |
461 | |
462 | /* Parse the 'interpreter' field. */ | |
1da177e4 LT |
463 | e->interpreter = p; |
464 | p = strchr(p, del); | |
465 | if (!p) | |
e6084d4a | 466 | goto einval; |
1da177e4 LT |
467 | *p++ = '\0'; |
468 | if (!e->interpreter[0]) | |
e6084d4a | 469 | goto einval; |
6b899c4e | 470 | pr_debug("register: interpreter: {%s}\n", e->interpreter); |
1da177e4 | 471 | |
6b899c4e | 472 | /* Parse the 'flags' field. */ |
e6084d4a | 473 | p = check_special_flags(p, e); |
1da177e4 LT |
474 | if (*p == '\n') |
475 | p++; | |
476 | if (p != buf + count) | |
e6084d4a MF |
477 | goto einval; |
478 | ||
1da177e4 LT |
479 | return e; |
480 | ||
481 | out: | |
482 | return ERR_PTR(err); | |
483 | ||
e6084d4a | 484 | efault: |
1da177e4 LT |
485 | kfree(e); |
486 | return ERR_PTR(-EFAULT); | |
e6084d4a | 487 | einval: |
1da177e4 LT |
488 | kfree(e); |
489 | return ERR_PTR(-EINVAL); | |
490 | } | |
491 | ||
492 | /* | |
493 | * Set status of entry/binfmt_misc: | |
494 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc | |
495 | */ | |
496 | static int parse_command(const char __user *buffer, size_t count) | |
497 | { | |
498 | char s[4]; | |
499 | ||
1da177e4 LT |
500 | if (count > 3) |
501 | return -EINVAL; | |
502 | if (copy_from_user(s, buffer, count)) | |
503 | return -EFAULT; | |
de8288b1 AB |
504 | if (!count) |
505 | return 0; | |
e6084d4a | 506 | if (s[count - 1] == '\n') |
1da177e4 LT |
507 | count--; |
508 | if (count == 1 && s[0] == '0') | |
509 | return 1; | |
510 | if (count == 1 && s[0] == '1') | |
511 | return 2; | |
512 | if (count == 2 && s[0] == '-' && s[1] == '1') | |
513 | return 3; | |
514 | return -EINVAL; | |
515 | } | |
516 | ||
517 | /* generic stuff */ | |
518 | ||
519 | static void entry_status(Node *e, char *page) | |
520 | { | |
521 | char *dp; | |
522 | char *status = "disabled"; | |
e6084d4a | 523 | const char *flags = "flags: "; |
1da177e4 LT |
524 | |
525 | if (test_bit(Enabled, &e->flags)) | |
526 | status = "enabled"; | |
527 | ||
528 | if (!VERBOSE_STATUS) { | |
529 | sprintf(page, "%s\n", status); | |
530 | return; | |
531 | } | |
532 | ||
533 | sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); | |
534 | dp = page + strlen(page); | |
535 | ||
536 | /* print the special flags */ | |
e6084d4a MF |
537 | sprintf(dp, "%s", flags); |
538 | dp += strlen(flags); | |
539 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) | |
540 | *dp++ = 'P'; | |
541 | if (e->flags & MISC_FMT_OPEN_BINARY) | |
542 | *dp++ = 'O'; | |
543 | if (e->flags & MISC_FMT_CREDENTIALS) | |
544 | *dp++ = 'C'; | |
545 | *dp++ = '\n'; | |
1da177e4 LT |
546 | |
547 | if (!test_bit(Magic, &e->flags)) { | |
548 | sprintf(dp, "extension .%s\n", e->magic); | |
549 | } else { | |
550 | int i; | |
551 | ||
552 | sprintf(dp, "offset %i\nmagic ", e->offset); | |
553 | dp = page + strlen(page); | |
554 | for (i = 0; i < e->size; i++) { | |
555 | sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); | |
556 | dp += 2; | |
557 | } | |
558 | if (e->mask) { | |
559 | sprintf(dp, "\nmask "); | |
560 | dp += 6; | |
561 | for (i = 0; i < e->size; i++) { | |
562 | sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); | |
563 | dp += 2; | |
564 | } | |
565 | } | |
566 | *dp++ = '\n'; | |
567 | *dp = '\0'; | |
568 | } | |
569 | } | |
570 | ||
571 | static struct inode *bm_get_inode(struct super_block *sb, int mode) | |
572 | { | |
e6084d4a | 573 | struct inode *inode = new_inode(sb); |
1da177e4 LT |
574 | |
575 | if (inode) { | |
85fe4025 | 576 | inode->i_ino = get_next_ino(); |
1da177e4 | 577 | inode->i_mode = mode; |
1da177e4 LT |
578 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
579 | current_fs_time(inode->i_sb); | |
580 | } | |
581 | return inode; | |
582 | } | |
583 | ||
b57922d9 | 584 | static void bm_evict_inode(struct inode *inode) |
1da177e4 | 585 | { |
dbd5768f | 586 | clear_inode(inode); |
8e18e294 | 587 | kfree(inode->i_private); |
1da177e4 LT |
588 | } |
589 | ||
590 | static void kill_node(Node *e) | |
591 | { | |
592 | struct dentry *dentry; | |
593 | ||
594 | write_lock(&entries_lock); | |
595 | dentry = e->dentry; | |
596 | if (dentry) { | |
597 | list_del_init(&e->list); | |
598 | e->dentry = NULL; | |
599 | } | |
600 | write_unlock(&entries_lock); | |
601 | ||
602 | if (dentry) { | |
6d6b77f1 | 603 | drop_nlink(dentry->d_inode); |
1da177e4 LT |
604 | d_drop(dentry); |
605 | dput(dentry); | |
606 | simple_release_fs(&bm_mnt, &entry_count); | |
607 | } | |
608 | } | |
609 | ||
610 | /* /<entry> */ | |
611 | ||
612 | static ssize_t | |
e6084d4a | 613 | bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
1da177e4 | 614 | { |
496ad9aa | 615 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
616 | ssize_t res; |
617 | char *page; | |
1da177e4 | 618 | |
e6084d4a MF |
619 | page = (char *) __get_free_page(GFP_KERNEL); |
620 | if (!page) | |
1da177e4 LT |
621 | return -ENOMEM; |
622 | ||
623 | entry_status(e, page); | |
1da177e4 | 624 | |
6e2c10a1 AM |
625 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
626 | ||
1da177e4 LT |
627 | free_page((unsigned long) page); |
628 | return res; | |
629 | } | |
630 | ||
631 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, | |
632 | size_t count, loff_t *ppos) | |
633 | { | |
634 | struct dentry *root; | |
496ad9aa | 635 | Node *e = file_inode(file)->i_private; |
1da177e4 LT |
636 | int res = parse_command(buffer, count); |
637 | ||
638 | switch (res) { | |
e6084d4a MF |
639 | case 1: |
640 | /* Disable this handler. */ | |
641 | clear_bit(Enabled, &e->flags); | |
642 | break; | |
643 | case 2: | |
644 | /* Enable this handler. */ | |
645 | set_bit(Enabled, &e->flags); | |
646 | break; | |
647 | case 3: | |
648 | /* Delete this handler. */ | |
649 | root = dget(file->f_path.dentry->d_sb->s_root); | |
650 | mutex_lock(&root->d_inode->i_mutex); | |
1da177e4 | 651 | |
e6084d4a | 652 | kill_node(e); |
1da177e4 | 653 | |
e6084d4a MF |
654 | mutex_unlock(&root->d_inode->i_mutex); |
655 | dput(root); | |
656 | break; | |
657 | default: | |
658 | return res; | |
1da177e4 | 659 | } |
e6084d4a | 660 | |
1da177e4 LT |
661 | return count; |
662 | } | |
663 | ||
4b6f5d20 | 664 | static const struct file_operations bm_entry_operations = { |
1da177e4 LT |
665 | .read = bm_entry_read, |
666 | .write = bm_entry_write, | |
6038f373 | 667 | .llseek = default_llseek, |
1da177e4 LT |
668 | }; |
669 | ||
670 | /* /register */ | |
671 | ||
672 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, | |
673 | size_t count, loff_t *ppos) | |
674 | { | |
675 | Node *e; | |
676 | struct inode *inode; | |
677 | struct dentry *root, *dentry; | |
d8c9584e | 678 | struct super_block *sb = file->f_path.dentry->d_sb; |
1da177e4 LT |
679 | int err = 0; |
680 | ||
681 | e = create_entry(buffer, count); | |
682 | ||
683 | if (IS_ERR(e)) | |
684 | return PTR_ERR(e); | |
685 | ||
686 | root = dget(sb->s_root); | |
1b1dcc1b | 687 | mutex_lock(&root->d_inode->i_mutex); |
1da177e4 LT |
688 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
689 | err = PTR_ERR(dentry); | |
690 | if (IS_ERR(dentry)) | |
691 | goto out; | |
692 | ||
693 | err = -EEXIST; | |
694 | if (dentry->d_inode) | |
695 | goto out2; | |
696 | ||
697 | inode = bm_get_inode(sb, S_IFREG | 0644); | |
698 | ||
699 | err = -ENOMEM; | |
700 | if (!inode) | |
701 | goto out2; | |
702 | ||
1f5ce9e9 | 703 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
1da177e4 LT |
704 | if (err) { |
705 | iput(inode); | |
706 | inode = NULL; | |
707 | goto out2; | |
708 | } | |
709 | ||
710 | e->dentry = dget(dentry); | |
8e18e294 | 711 | inode->i_private = e; |
1da177e4 LT |
712 | inode->i_fop = &bm_entry_operations; |
713 | ||
714 | d_instantiate(dentry, inode); | |
715 | write_lock(&entries_lock); | |
716 | list_add(&e->list, &entries); | |
717 | write_unlock(&entries_lock); | |
718 | ||
719 | err = 0; | |
720 | out2: | |
721 | dput(dentry); | |
722 | out: | |
1b1dcc1b | 723 | mutex_unlock(&root->d_inode->i_mutex); |
1da177e4 LT |
724 | dput(root); |
725 | ||
726 | if (err) { | |
727 | kfree(e); | |
728 | return -EINVAL; | |
729 | } | |
730 | return count; | |
731 | } | |
732 | ||
4b6f5d20 | 733 | static const struct file_operations bm_register_operations = { |
1da177e4 | 734 | .write = bm_register_write, |
6038f373 | 735 | .llseek = noop_llseek, |
1da177e4 LT |
736 | }; |
737 | ||
738 | /* /status */ | |
739 | ||
740 | static ssize_t | |
741 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) | |
742 | { | |
87113e80 | 743 | char *s = enabled ? "enabled\n" : "disabled\n"; |
1da177e4 | 744 | |
92f4c701 | 745 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
1da177e4 LT |
746 | } |
747 | ||
e6084d4a | 748 | static ssize_t bm_status_write(struct file *file, const char __user *buffer, |
1da177e4 LT |
749 | size_t count, loff_t *ppos) |
750 | { | |
751 | int res = parse_command(buffer, count); | |
752 | struct dentry *root; | |
753 | ||
754 | switch (res) { | |
e6084d4a MF |
755 | case 1: |
756 | /* Disable all handlers. */ | |
757 | enabled = 0; | |
758 | break; | |
759 | case 2: | |
760 | /* Enable all handlers. */ | |
761 | enabled = 1; | |
762 | break; | |
763 | case 3: | |
764 | /* Delete all handlers. */ | |
765 | root = dget(file->f_path.dentry->d_sb->s_root); | |
766 | mutex_lock(&root->d_inode->i_mutex); | |
1da177e4 | 767 | |
e6084d4a MF |
768 | while (!list_empty(&entries)) |
769 | kill_node(list_entry(entries.next, Node, list)); | |
1da177e4 | 770 | |
e6084d4a MF |
771 | mutex_unlock(&root->d_inode->i_mutex); |
772 | dput(root); | |
773 | break; | |
774 | default: | |
775 | return res; | |
1da177e4 | 776 | } |
e6084d4a | 777 | |
1da177e4 LT |
778 | return count; |
779 | } | |
780 | ||
4b6f5d20 | 781 | static const struct file_operations bm_status_operations = { |
1da177e4 LT |
782 | .read = bm_status_read, |
783 | .write = bm_status_write, | |
6038f373 | 784 | .llseek = default_llseek, |
1da177e4 LT |
785 | }; |
786 | ||
787 | /* Superblock handling */ | |
788 | ||
ee9b6d61 | 789 | static const struct super_operations s_ops = { |
1da177e4 | 790 | .statfs = simple_statfs, |
b57922d9 | 791 | .evict_inode = bm_evict_inode, |
1da177e4 LT |
792 | }; |
793 | ||
e6084d4a | 794 | static int bm_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 | 795 | { |
e6084d4a | 796 | int err; |
1da177e4 | 797 | static struct tree_descr bm_files[] = { |
1a1c9bb4 JL |
798 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
799 | [3] = {"register", &bm_register_operations, S_IWUSR}, | |
1da177e4 LT |
800 | /* last one */ {""} |
801 | }; | |
e6084d4a MF |
802 | |
803 | err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); | |
1da177e4 LT |
804 | if (!err) |
805 | sb->s_op = &s_ops; | |
806 | return err; | |
807 | } | |
808 | ||
fc14f2fe AV |
809 | static struct dentry *bm_mount(struct file_system_type *fs_type, |
810 | int flags, const char *dev_name, void *data) | |
1da177e4 | 811 | { |
fc14f2fe | 812 | return mount_single(fs_type, flags, data, bm_fill_super); |
1da177e4 LT |
813 | } |
814 | ||
815 | static struct linux_binfmt misc_format = { | |
816 | .module = THIS_MODULE, | |
817 | .load_binary = load_misc_binary, | |
818 | }; | |
819 | ||
820 | static struct file_system_type bm_fs_type = { | |
821 | .owner = THIS_MODULE, | |
822 | .name = "binfmt_misc", | |
fc14f2fe | 823 | .mount = bm_mount, |
1da177e4 LT |
824 | .kill_sb = kill_litter_super, |
825 | }; | |
7f78e035 | 826 | MODULE_ALIAS_FS("binfmt_misc"); |
1da177e4 LT |
827 | |
828 | static int __init init_misc_binfmt(void) | |
829 | { | |
830 | int err = register_filesystem(&bm_fs_type); | |
8fc3dc5a AV |
831 | if (!err) |
832 | insert_binfmt(&misc_format); | |
1da177e4 LT |
833 | return err; |
834 | } | |
835 | ||
836 | static void __exit exit_misc_binfmt(void) | |
837 | { | |
838 | unregister_binfmt(&misc_format); | |
839 | unregister_filesystem(&bm_fs_type); | |
840 | } | |
841 | ||
842 | core_initcall(init_misc_binfmt); | |
843 | module_exit(exit_misc_binfmt); | |
844 | MODULE_LICENSE("GPL"); |