Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * binfmt_misc.c |
| 3 | * |
Jan Engelhardt | 96de0e2 | 2007-10-19 23:21:04 +0200 | [diff] [blame^] | 4 | * Copyright (C) 1997 Richard Günther |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Alexey Dobriyan | e8edc6e | 2007-05-21 01:22:52 +0400 | [diff] [blame] | 21 | #include <linux/sched.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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); |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 58 | static struct file_system_type bm_fs_type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
| 113 | struct files_struct *files = NULL; |
| 114 | |
| 115 | retval = -ENOEXEC; |
| 116 | if (!enabled) |
| 117 | goto _ret; |
| 118 | |
| 119 | /* to keep locking time low, we copy the interpreter string */ |
| 120 | read_lock(&entries_lock); |
| 121 | fmt = check_file(bprm); |
| 122 | if (fmt) |
| 123 | strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); |
| 124 | read_unlock(&entries_lock); |
| 125 | if (!fmt) |
| 126 | goto _ret; |
| 127 | |
| 128 | if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 129 | retval = remove_arg_zero(bprm); |
| 130 | if (retval) |
| 131 | goto _ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | } |
| 133 | |
| 134 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { |
| 135 | |
| 136 | files = current->files; |
| 137 | retval = unshare_files(); |
| 138 | if (retval < 0) |
| 139 | goto _ret; |
| 140 | if (files == current->files) { |
| 141 | put_files_struct(files); |
| 142 | files = NULL; |
| 143 | } |
| 144 | /* if the binary should be opened on behalf of the |
| 145 | * interpreter than keep it open and assign descriptor |
| 146 | * to it */ |
| 147 | fd_binary = get_unused_fd(); |
| 148 | if (fd_binary < 0) { |
| 149 | retval = fd_binary; |
| 150 | goto _unshare; |
| 151 | } |
| 152 | fd_install(fd_binary, bprm->file); |
| 153 | |
| 154 | /* if the binary is not readable than enforce mm->dumpable=0 |
| 155 | regardless of the interpreter's permissions */ |
Christoph Hellwig | 8c744fb | 2005-11-08 21:35:04 -0800 | [diff] [blame] | 156 | if (file_permission(bprm->file, MAY_READ)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
| 158 | |
| 159 | allow_write_access(bprm->file); |
| 160 | bprm->file = NULL; |
| 161 | |
| 162 | /* mark the bprm that fd should be passed to interp */ |
| 163 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; |
| 164 | bprm->interp_data = fd_binary; |
| 165 | |
| 166 | } else { |
| 167 | allow_write_access(bprm->file); |
| 168 | fput(bprm->file); |
| 169 | bprm->file = NULL; |
| 170 | } |
| 171 | /* make argv[1] be the path to the binary */ |
| 172 | retval = copy_strings_kernel (1, &bprm->interp, bprm); |
| 173 | if (retval < 0) |
| 174 | goto _error; |
| 175 | bprm->argc++; |
| 176 | |
| 177 | /* add the interp as argv[0] */ |
| 178 | retval = copy_strings_kernel (1, &iname_addr, bprm); |
| 179 | if (retval < 0) |
| 180 | goto _error; |
| 181 | bprm->argc ++; |
| 182 | |
| 183 | bprm->interp = iname; /* for binfmt_script */ |
| 184 | |
| 185 | interp_file = open_exec (iname); |
| 186 | retval = PTR_ERR (interp_file); |
| 187 | if (IS_ERR (interp_file)) |
| 188 | goto _error; |
| 189 | |
| 190 | bprm->file = interp_file; |
| 191 | if (fmt->flags & MISC_FMT_CREDENTIALS) { |
| 192 | /* |
| 193 | * No need to call prepare_binprm(), it's already been |
| 194 | * done. bprm->buf is stale, update from interp_file. |
| 195 | */ |
| 196 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
| 197 | retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); |
| 198 | } else |
| 199 | retval = prepare_binprm (bprm); |
| 200 | |
| 201 | if (retval < 0) |
| 202 | goto _error; |
| 203 | |
| 204 | retval = search_binary_handler (bprm, regs); |
| 205 | if (retval < 0) |
| 206 | goto _error; |
| 207 | |
| 208 | if (files) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | put_files_struct(files); |
| 210 | files = NULL; |
| 211 | } |
| 212 | _ret: |
| 213 | return retval; |
| 214 | _error: |
| 215 | if (fd_binary > 0) |
| 216 | sys_close(fd_binary); |
| 217 | bprm->interp_flags = 0; |
| 218 | bprm->interp_data = 0; |
| 219 | _unshare: |
Kirill Korotaev | 3b9b8ab | 2006-09-29 02:00:05 -0700 | [diff] [blame] | 220 | if (files) |
| 221 | reset_files_struct(current, files); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | goto _ret; |
| 223 | } |
| 224 | |
| 225 | /* Command parsers */ |
| 226 | |
| 227 | /* |
| 228 | * parses and copies one argument enclosed in del from *sp to *dp, |
| 229 | * recognising the \x special. |
| 230 | * returns pointer to the copied argument or NULL in case of an |
| 231 | * error (and sets err) or null argument length. |
| 232 | */ |
| 233 | static char *scanarg(char *s, char del) |
| 234 | { |
| 235 | char c; |
| 236 | |
| 237 | while ((c = *s++) != del) { |
| 238 | if (c == '\\' && *s == 'x') { |
| 239 | s++; |
| 240 | if (!isxdigit(*s++)) |
| 241 | return NULL; |
| 242 | if (!isxdigit(*s++)) |
| 243 | return NULL; |
| 244 | } |
| 245 | } |
| 246 | return s; |
| 247 | } |
| 248 | |
| 249 | static int unquote(char *from) |
| 250 | { |
| 251 | char c = 0, *s = from, *p = from; |
| 252 | |
| 253 | while ((c = *s++) != '\0') { |
| 254 | if (c == '\\' && *s == 'x') { |
| 255 | s++; |
| 256 | c = toupper(*s++); |
| 257 | *p = (c - (isdigit(c) ? '0' : 'A' - 10)) << 4; |
| 258 | c = toupper(*s++); |
| 259 | *p++ |= c - (isdigit(c) ? '0' : 'A' - 10); |
| 260 | continue; |
| 261 | } |
| 262 | *p++ = c; |
| 263 | } |
| 264 | return p - from; |
| 265 | } |
| 266 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 267 | static char * check_special_flags (char * sfs, Node * e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | { |
| 269 | char * p = sfs; |
| 270 | int cont = 1; |
| 271 | |
| 272 | /* special flags */ |
| 273 | while (cont) { |
| 274 | switch (*p) { |
| 275 | case 'P': |
| 276 | p++; |
| 277 | e->flags |= MISC_FMT_PRESERVE_ARGV0; |
| 278 | break; |
| 279 | case 'O': |
| 280 | p++; |
| 281 | e->flags |= MISC_FMT_OPEN_BINARY; |
| 282 | break; |
| 283 | case 'C': |
| 284 | p++; |
| 285 | /* this flags also implies the |
| 286 | open-binary flag */ |
| 287 | e->flags |= (MISC_FMT_CREDENTIALS | |
| 288 | MISC_FMT_OPEN_BINARY); |
| 289 | break; |
| 290 | default: |
| 291 | cont = 0; |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | return p; |
| 296 | } |
| 297 | /* |
| 298 | * This registers a new binary format, it recognises the syntax |
| 299 | * ':name:type:offset:magic:mask:interpreter:flags' |
| 300 | * where the ':' is the IFS, that can be chosen with the first char |
| 301 | */ |
| 302 | static Node *create_entry(const char __user *buffer, size_t count) |
| 303 | { |
| 304 | Node *e; |
| 305 | int memsize, err; |
| 306 | char *buf, *p; |
| 307 | char del; |
| 308 | |
| 309 | /* some sanity checks */ |
| 310 | err = -EINVAL; |
| 311 | if ((count < 11) || (count > 256)) |
| 312 | goto out; |
| 313 | |
| 314 | err = -ENOMEM; |
| 315 | memsize = sizeof(Node) + count + 8; |
Robert P. J. Day | 5cbded5 | 2006-12-13 00:35:56 -0800 | [diff] [blame] | 316 | e = kmalloc(memsize, GFP_USER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | if (!e) |
| 318 | goto out; |
| 319 | |
| 320 | p = buf = (char *)e + sizeof(Node); |
| 321 | |
| 322 | memset(e, 0, sizeof(Node)); |
| 323 | if (copy_from_user(buf, buffer, count)) |
| 324 | goto Efault; |
| 325 | |
| 326 | del = *p++; /* delimeter */ |
| 327 | |
| 328 | memset(buf+count, del, 8); |
| 329 | |
| 330 | e->name = p; |
| 331 | p = strchr(p, del); |
| 332 | if (!p) |
| 333 | goto Einval; |
| 334 | *p++ = '\0'; |
| 335 | if (!e->name[0] || |
| 336 | !strcmp(e->name, ".") || |
| 337 | !strcmp(e->name, "..") || |
| 338 | strchr(e->name, '/')) |
| 339 | goto Einval; |
| 340 | switch (*p++) { |
| 341 | case 'E': e->flags = 1<<Enabled; break; |
| 342 | case 'M': e->flags = (1<<Enabled) | (1<<Magic); break; |
| 343 | default: goto Einval; |
| 344 | } |
| 345 | if (*p++ != del) |
| 346 | goto Einval; |
| 347 | if (test_bit(Magic, &e->flags)) { |
| 348 | char *s = strchr(p, del); |
| 349 | if (!s) |
| 350 | goto Einval; |
| 351 | *s++ = '\0'; |
| 352 | e->offset = simple_strtoul(p, &p, 10); |
| 353 | if (*p++) |
| 354 | goto Einval; |
| 355 | e->magic = p; |
| 356 | p = scanarg(p, del); |
| 357 | if (!p) |
| 358 | goto Einval; |
| 359 | p[-1] = '\0'; |
| 360 | if (!e->magic[0]) |
| 361 | goto Einval; |
| 362 | e->mask = p; |
| 363 | p = scanarg(p, del); |
| 364 | if (!p) |
| 365 | goto Einval; |
| 366 | p[-1] = '\0'; |
| 367 | if (!e->mask[0]) |
| 368 | e->mask = NULL; |
| 369 | e->size = unquote(e->magic); |
| 370 | if (e->mask && unquote(e->mask) != e->size) |
| 371 | goto Einval; |
| 372 | if (e->size + e->offset > BINPRM_BUF_SIZE) |
| 373 | goto Einval; |
| 374 | } else { |
| 375 | p = strchr(p, del); |
| 376 | if (!p) |
| 377 | goto Einval; |
| 378 | *p++ = '\0'; |
| 379 | e->magic = p; |
| 380 | p = strchr(p, del); |
| 381 | if (!p) |
| 382 | goto Einval; |
| 383 | *p++ = '\0'; |
| 384 | if (!e->magic[0] || strchr(e->magic, '/')) |
| 385 | goto Einval; |
| 386 | p = strchr(p, del); |
| 387 | if (!p) |
| 388 | goto Einval; |
| 389 | *p++ = '\0'; |
| 390 | } |
| 391 | e->interpreter = p; |
| 392 | p = strchr(p, del); |
| 393 | if (!p) |
| 394 | goto Einval; |
| 395 | *p++ = '\0'; |
| 396 | if (!e->interpreter[0]) |
| 397 | goto Einval; |
| 398 | |
| 399 | |
| 400 | p = check_special_flags (p, e); |
| 401 | |
| 402 | if (*p == '\n') |
| 403 | p++; |
| 404 | if (p != buf + count) |
| 405 | goto Einval; |
| 406 | return e; |
| 407 | |
| 408 | out: |
| 409 | return ERR_PTR(err); |
| 410 | |
| 411 | Efault: |
| 412 | kfree(e); |
| 413 | return ERR_PTR(-EFAULT); |
| 414 | Einval: |
| 415 | kfree(e); |
| 416 | return ERR_PTR(-EINVAL); |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * Set status of entry/binfmt_misc: |
| 421 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc |
| 422 | */ |
| 423 | static int parse_command(const char __user *buffer, size_t count) |
| 424 | { |
| 425 | char s[4]; |
| 426 | |
| 427 | if (!count) |
| 428 | return 0; |
| 429 | if (count > 3) |
| 430 | return -EINVAL; |
| 431 | if (copy_from_user(s, buffer, count)) |
| 432 | return -EFAULT; |
| 433 | if (s[count-1] == '\n') |
| 434 | count--; |
| 435 | if (count == 1 && s[0] == '0') |
| 436 | return 1; |
| 437 | if (count == 1 && s[0] == '1') |
| 438 | return 2; |
| 439 | if (count == 2 && s[0] == '-' && s[1] == '1') |
| 440 | return 3; |
| 441 | return -EINVAL; |
| 442 | } |
| 443 | |
| 444 | /* generic stuff */ |
| 445 | |
| 446 | static void entry_status(Node *e, char *page) |
| 447 | { |
| 448 | char *dp; |
| 449 | char *status = "disabled"; |
| 450 | const char * flags = "flags: "; |
| 451 | |
| 452 | if (test_bit(Enabled, &e->flags)) |
| 453 | status = "enabled"; |
| 454 | |
| 455 | if (!VERBOSE_STATUS) { |
| 456 | sprintf(page, "%s\n", status); |
| 457 | return; |
| 458 | } |
| 459 | |
| 460 | sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); |
| 461 | dp = page + strlen(page); |
| 462 | |
| 463 | /* print the special flags */ |
| 464 | sprintf (dp, "%s", flags); |
| 465 | dp += strlen (flags); |
| 466 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) { |
| 467 | *dp ++ = 'P'; |
| 468 | } |
| 469 | if (e->flags & MISC_FMT_OPEN_BINARY) { |
| 470 | *dp ++ = 'O'; |
| 471 | } |
| 472 | if (e->flags & MISC_FMT_CREDENTIALS) { |
| 473 | *dp ++ = 'C'; |
| 474 | } |
| 475 | *dp ++ = '\n'; |
| 476 | |
| 477 | |
| 478 | if (!test_bit(Magic, &e->flags)) { |
| 479 | sprintf(dp, "extension .%s\n", e->magic); |
| 480 | } else { |
| 481 | int i; |
| 482 | |
| 483 | sprintf(dp, "offset %i\nmagic ", e->offset); |
| 484 | dp = page + strlen(page); |
| 485 | for (i = 0; i < e->size; i++) { |
| 486 | sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); |
| 487 | dp += 2; |
| 488 | } |
| 489 | if (e->mask) { |
| 490 | sprintf(dp, "\nmask "); |
| 491 | dp += 6; |
| 492 | for (i = 0; i < e->size; i++) { |
| 493 | sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); |
| 494 | dp += 2; |
| 495 | } |
| 496 | } |
| 497 | *dp++ = '\n'; |
| 498 | *dp = '\0'; |
| 499 | } |
| 500 | } |
| 501 | |
| 502 | static struct inode *bm_get_inode(struct super_block *sb, int mode) |
| 503 | { |
| 504 | struct inode * inode = new_inode(sb); |
| 505 | |
| 506 | if (inode) { |
| 507 | inode->i_mode = mode; |
| 508 | inode->i_uid = 0; |
| 509 | inode->i_gid = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | inode->i_blocks = 0; |
| 511 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
| 512 | current_fs_time(inode->i_sb); |
| 513 | } |
| 514 | return inode; |
| 515 | } |
| 516 | |
| 517 | static void bm_clear_inode(struct inode *inode) |
| 518 | { |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 519 | kfree(inode->i_private); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | } |
| 521 | |
| 522 | static void kill_node(Node *e) |
| 523 | { |
| 524 | struct dentry *dentry; |
| 525 | |
| 526 | write_lock(&entries_lock); |
| 527 | dentry = e->dentry; |
| 528 | if (dentry) { |
| 529 | list_del_init(&e->list); |
| 530 | e->dentry = NULL; |
| 531 | } |
| 532 | write_unlock(&entries_lock); |
| 533 | |
| 534 | if (dentry) { |
| 535 | dentry->d_inode->i_nlink--; |
| 536 | d_drop(dentry); |
| 537 | dput(dentry); |
| 538 | simple_release_fs(&bm_mnt, &entry_count); |
| 539 | } |
| 540 | } |
| 541 | |
| 542 | /* /<entry> */ |
| 543 | |
| 544 | static ssize_t |
| 545 | bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos) |
| 546 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 547 | Node *e = file->f_path.dentry->d_inode->i_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | loff_t pos = *ppos; |
| 549 | ssize_t res; |
| 550 | char *page; |
| 551 | int len; |
| 552 | |
| 553 | if (!(page = (char*) __get_free_page(GFP_KERNEL))) |
| 554 | return -ENOMEM; |
| 555 | |
| 556 | entry_status(e, page); |
| 557 | len = strlen(page); |
| 558 | |
| 559 | res = -EINVAL; |
| 560 | if (pos < 0) |
| 561 | goto out; |
| 562 | res = 0; |
| 563 | if (pos >= len) |
| 564 | goto out; |
| 565 | if (len < pos + nbytes) |
| 566 | nbytes = len - pos; |
| 567 | res = -EFAULT; |
| 568 | if (copy_to_user(buf, page + pos, nbytes)) |
| 569 | goto out; |
| 570 | *ppos = pos + nbytes; |
| 571 | res = nbytes; |
| 572 | out: |
| 573 | free_page((unsigned long) page); |
| 574 | return res; |
| 575 | } |
| 576 | |
| 577 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, |
| 578 | size_t count, loff_t *ppos) |
| 579 | { |
| 580 | struct dentry *root; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 581 | Node *e = file->f_path.dentry->d_inode->i_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | int res = parse_command(buffer, count); |
| 583 | |
| 584 | switch (res) { |
| 585 | case 1: clear_bit(Enabled, &e->flags); |
| 586 | break; |
| 587 | case 2: set_bit(Enabled, &e->flags); |
| 588 | break; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 589 | case 3: root = dget(file->f_path.mnt->mnt_sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 590 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | |
| 592 | kill_node(e); |
| 593 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 594 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | dput(root); |
| 596 | break; |
| 597 | default: return res; |
| 598 | } |
| 599 | return count; |
| 600 | } |
| 601 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 602 | static const struct file_operations bm_entry_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 603 | .read = bm_entry_read, |
| 604 | .write = bm_entry_write, |
| 605 | }; |
| 606 | |
| 607 | /* /register */ |
| 608 | |
| 609 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, |
| 610 | size_t count, loff_t *ppos) |
| 611 | { |
| 612 | Node *e; |
| 613 | struct inode *inode; |
| 614 | struct dentry *root, *dentry; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 615 | struct super_block *sb = file->f_path.mnt->mnt_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | int err = 0; |
| 617 | |
| 618 | e = create_entry(buffer, count); |
| 619 | |
| 620 | if (IS_ERR(e)) |
| 621 | return PTR_ERR(e); |
| 622 | |
| 623 | root = dget(sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 624 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
| 626 | err = PTR_ERR(dentry); |
| 627 | if (IS_ERR(dentry)) |
| 628 | goto out; |
| 629 | |
| 630 | err = -EEXIST; |
| 631 | if (dentry->d_inode) |
| 632 | goto out2; |
| 633 | |
| 634 | inode = bm_get_inode(sb, S_IFREG | 0644); |
| 635 | |
| 636 | err = -ENOMEM; |
| 637 | if (!inode) |
| 638 | goto out2; |
| 639 | |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 640 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 641 | if (err) { |
| 642 | iput(inode); |
| 643 | inode = NULL; |
| 644 | goto out2; |
| 645 | } |
| 646 | |
| 647 | e->dentry = dget(dentry); |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 648 | inode->i_private = e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | inode->i_fop = &bm_entry_operations; |
| 650 | |
| 651 | d_instantiate(dentry, inode); |
| 652 | write_lock(&entries_lock); |
| 653 | list_add(&e->list, &entries); |
| 654 | write_unlock(&entries_lock); |
| 655 | |
| 656 | err = 0; |
| 657 | out2: |
| 658 | dput(dentry); |
| 659 | out: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 660 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | dput(root); |
| 662 | |
| 663 | if (err) { |
| 664 | kfree(e); |
| 665 | return -EINVAL; |
| 666 | } |
| 667 | return count; |
| 668 | } |
| 669 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 670 | static const struct file_operations bm_register_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | .write = bm_register_write, |
| 672 | }; |
| 673 | |
| 674 | /* /status */ |
| 675 | |
| 676 | static ssize_t |
| 677 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
| 678 | { |
| 679 | char *s = enabled ? "enabled" : "disabled"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | |
Akinobu Mita | 92f4c70 | 2007-05-09 02:33:32 -0700 | [diff] [blame] | 681 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 682 | } |
| 683 | |
| 684 | static ssize_t bm_status_write(struct file * file, const char __user * buffer, |
| 685 | size_t count, loff_t *ppos) |
| 686 | { |
| 687 | int res = parse_command(buffer, count); |
| 688 | struct dentry *root; |
| 689 | |
| 690 | switch (res) { |
| 691 | case 1: enabled = 0; break; |
| 692 | case 2: enabled = 1; break; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 693 | case 3: root = dget(file->f_path.mnt->mnt_sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 694 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 695 | |
| 696 | while (!list_empty(&entries)) |
| 697 | kill_node(list_entry(entries.next, Node, list)); |
| 698 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 699 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | dput(root); |
| 701 | default: return res; |
| 702 | } |
| 703 | return count; |
| 704 | } |
| 705 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 706 | static const struct file_operations bm_status_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 707 | .read = bm_status_read, |
| 708 | .write = bm_status_write, |
| 709 | }; |
| 710 | |
| 711 | /* Superblock handling */ |
| 712 | |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 713 | static const struct super_operations s_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 714 | .statfs = simple_statfs, |
| 715 | .clear_inode = bm_clear_inode, |
| 716 | }; |
| 717 | |
| 718 | static int bm_fill_super(struct super_block * sb, void * data, int silent) |
| 719 | { |
| 720 | static struct tree_descr bm_files[] = { |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 721 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
| 722 | [3] = {"register", &bm_register_operations, S_IWUSR}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 723 | /* last one */ {""} |
| 724 | }; |
| 725 | int err = simple_fill_super(sb, 0x42494e4d, bm_files); |
| 726 | if (!err) |
| 727 | sb->s_op = &s_ops; |
| 728 | return err; |
| 729 | } |
| 730 | |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 731 | static int bm_get_sb(struct file_system_type *fs_type, |
| 732 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 | { |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame] | 734 | return get_sb_single(fs_type, flags, data, bm_fill_super, mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | } |
| 736 | |
| 737 | static struct linux_binfmt misc_format = { |
| 738 | .module = THIS_MODULE, |
| 739 | .load_binary = load_misc_binary, |
| 740 | }; |
| 741 | |
| 742 | static struct file_system_type bm_fs_type = { |
| 743 | .owner = THIS_MODULE, |
| 744 | .name = "binfmt_misc", |
| 745 | .get_sb = bm_get_sb, |
| 746 | .kill_sb = kill_litter_super, |
| 747 | }; |
| 748 | |
| 749 | static int __init init_misc_binfmt(void) |
| 750 | { |
| 751 | int err = register_filesystem(&bm_fs_type); |
| 752 | if (!err) { |
| 753 | err = register_binfmt(&misc_format); |
| 754 | if (err) |
| 755 | unregister_filesystem(&bm_fs_type); |
| 756 | } |
| 757 | return err; |
| 758 | } |
| 759 | |
| 760 | static void __exit exit_misc_binfmt(void) |
| 761 | { |
| 762 | unregister_binfmt(&misc_format); |
| 763 | unregister_filesystem(&bm_fs_type); |
| 764 | } |
| 765 | |
| 766 | core_initcall(init_misc_binfmt); |
| 767 | module_exit(exit_misc_binfmt); |
| 768 | MODULE_LICENSE("GPL"); |