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> |
Muthu Kumar | b502bd1 | 2012-03-23 15:01:50 -0700 | [diff] [blame^] | 22 | #include <linux/magic.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/binfmts.h> |
| 24 | #include <linux/slab.h> |
| 25 | #include <linux/ctype.h> |
| 26 | #include <linux/file.h> |
| 27 | #include <linux/pagemap.h> |
| 28 | #include <linux/namei.h> |
| 29 | #include <linux/mount.h> |
| 30 | #include <linux/syscalls.h> |
Akinobu Mita | 6e2c10a | 2008-07-23 21:29:15 -0700 | [diff] [blame] | 31 | #include <linux/fs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
| 33 | #include <asm/uaccess.h> |
| 34 | |
| 35 | enum { |
| 36 | VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ |
| 37 | }; |
| 38 | |
| 39 | static LIST_HEAD(entries); |
| 40 | static int enabled = 1; |
| 41 | |
| 42 | enum {Enabled, Magic}; |
| 43 | #define MISC_FMT_PRESERVE_ARGV0 (1<<31) |
| 44 | #define MISC_FMT_OPEN_BINARY (1<<30) |
| 45 | #define MISC_FMT_CREDENTIALS (1<<29) |
| 46 | |
| 47 | typedef struct { |
| 48 | struct list_head list; |
| 49 | unsigned long flags; /* type, status, etc. */ |
| 50 | int offset; /* offset of magic */ |
| 51 | int size; /* size of magic/mask */ |
| 52 | char *magic; /* magic or filename extension */ |
| 53 | char *mask; /* mask, NULL for exact match */ |
| 54 | char *interpreter; /* filename of interpreter */ |
| 55 | char *name; |
| 56 | struct dentry *dentry; |
| 57 | } Node; |
| 58 | |
| 59 | static DEFINE_RWLOCK(entries_lock); |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 60 | static struct file_system_type bm_fs_type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | static struct vfsmount *bm_mnt; |
| 62 | static int entry_count; |
| 63 | |
| 64 | /* |
| 65 | * Check if we support the binfmt |
| 66 | * if we do, return the node, else NULL |
| 67 | * locking is done in load_misc_binary |
| 68 | */ |
| 69 | static Node *check_file(struct linux_binprm *bprm) |
| 70 | { |
| 71 | char *p = strrchr(bprm->interp, '.'); |
| 72 | struct list_head *l; |
| 73 | |
| 74 | list_for_each(l, &entries) { |
| 75 | Node *e = list_entry(l, Node, list); |
| 76 | char *s; |
| 77 | int j; |
| 78 | |
| 79 | if (!test_bit(Enabled, &e->flags)) |
| 80 | continue; |
| 81 | |
| 82 | if (!test_bit(Magic, &e->flags)) { |
| 83 | if (p && !strcmp(e->magic, p + 1)) |
| 84 | return e; |
| 85 | continue; |
| 86 | } |
| 87 | |
| 88 | s = bprm->buf + e->offset; |
| 89 | if (e->mask) { |
| 90 | for (j = 0; j < e->size; j++) |
| 91 | if ((*s++ ^ e->magic[j]) & e->mask[j]) |
| 92 | break; |
| 93 | } else { |
| 94 | for (j = 0; j < e->size; j++) |
| 95 | if ((*s++ ^ e->magic[j])) |
| 96 | break; |
| 97 | } |
| 98 | if (j == e->size) |
| 99 | return e; |
| 100 | } |
| 101 | return NULL; |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * the loader itself |
| 106 | */ |
| 107 | static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs) |
| 108 | { |
| 109 | Node *fmt; |
| 110 | struct file * interp_file = NULL; |
| 111 | char iname[BINPRM_BUF_SIZE]; |
David Howells | d762746 | 2010-08-17 23:52:56 +0100 | [diff] [blame] | 112 | const char *iname_addr = iname; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | int retval; |
| 114 | int fd_binary = -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | |
| 116 | retval = -ENOEXEC; |
| 117 | if (!enabled) |
| 118 | goto _ret; |
| 119 | |
Pavel Emelyanov | 3a2e7f4 | 2008-04-29 00:59:24 -0700 | [diff] [blame] | 120 | retval = -ENOEXEC; |
Kirill A. Shutemov | bf2a9a3 | 2008-10-15 22:02:39 -0700 | [diff] [blame] | 121 | if (bprm->recursion_depth > BINPRM_MAX_RECURSION) |
Pavel Emelyanov | 3a2e7f4 | 2008-04-29 00:59:24 -0700 | [diff] [blame] | 122 | goto _ret; |
| 123 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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)) { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 134 | retval = remove_arg_zero(bprm); |
| 135 | if (retval) |
| 136 | goto _ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | } |
| 138 | |
| 139 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { |
| 140 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
Al Viro | fd8328b | 2008-04-22 05:11:59 -0400 | [diff] [blame] | 147 | goto _ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 */ |
Al Viro | 1b5d783 | 2011-06-19 12:49:47 -0400 | [diff] [blame] | 153 | would_dump(bprm, bprm->file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | |
| 155 | allow_write_access(bprm->file); |
| 156 | bprm->file = NULL; |
| 157 | |
| 158 | /* mark the bprm that fd should be passed to interp */ |
| 159 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; |
| 160 | bprm->interp_data = fd_binary; |
| 161 | |
| 162 | } else { |
| 163 | allow_write_access(bprm->file); |
| 164 | fput(bprm->file); |
| 165 | bprm->file = NULL; |
| 166 | } |
| 167 | /* make argv[1] be the path to the binary */ |
| 168 | retval = copy_strings_kernel (1, &bprm->interp, bprm); |
| 169 | if (retval < 0) |
| 170 | goto _error; |
| 171 | bprm->argc++; |
| 172 | |
| 173 | /* add the interp as argv[0] */ |
| 174 | retval = copy_strings_kernel (1, &iname_addr, bprm); |
| 175 | if (retval < 0) |
| 176 | goto _error; |
| 177 | bprm->argc ++; |
| 178 | |
| 179 | bprm->interp = iname; /* for binfmt_script */ |
| 180 | |
| 181 | interp_file = open_exec (iname); |
| 182 | retval = PTR_ERR (interp_file); |
| 183 | if (IS_ERR (interp_file)) |
| 184 | goto _error; |
| 185 | |
| 186 | bprm->file = interp_file; |
| 187 | if (fmt->flags & MISC_FMT_CREDENTIALS) { |
| 188 | /* |
| 189 | * No need to call prepare_binprm(), it's already been |
| 190 | * done. bprm->buf is stale, update from interp_file. |
| 191 | */ |
| 192 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
| 193 | retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); |
| 194 | } else |
| 195 | retval = prepare_binprm (bprm); |
| 196 | |
| 197 | if (retval < 0) |
| 198 | goto _error; |
| 199 | |
Kirill A. Shutemov | bf2a9a3 | 2008-10-15 22:02:39 -0700 | [diff] [blame] | 200 | bprm->recursion_depth++; |
Pavel Emelyanov | ff9bc51 | 2008-08-20 14:09:10 -0700 | [diff] [blame] | 201 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | retval = search_binary_handler (bprm, regs); |
| 203 | if (retval < 0) |
| 204 | goto _error; |
| 205 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | _ret: |
| 207 | return retval; |
| 208 | _error: |
| 209 | if (fd_binary > 0) |
| 210 | sys_close(fd_binary); |
| 211 | bprm->interp_flags = 0; |
| 212 | bprm->interp_data = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | goto _ret; |
| 214 | } |
| 215 | |
| 216 | /* Command parsers */ |
| 217 | |
| 218 | /* |
| 219 | * parses and copies one argument enclosed in del from *sp to *dp, |
| 220 | * recognising the \x special. |
| 221 | * returns pointer to the copied argument or NULL in case of an |
| 222 | * error (and sets err) or null argument length. |
| 223 | */ |
| 224 | static char *scanarg(char *s, char del) |
| 225 | { |
| 226 | char c; |
| 227 | |
| 228 | while ((c = *s++) != del) { |
| 229 | if (c == '\\' && *s == 'x') { |
| 230 | s++; |
| 231 | if (!isxdigit(*s++)) |
| 232 | return NULL; |
| 233 | if (!isxdigit(*s++)) |
| 234 | return NULL; |
| 235 | } |
| 236 | } |
| 237 | return s; |
| 238 | } |
| 239 | |
| 240 | static int unquote(char *from) |
| 241 | { |
| 242 | char c = 0, *s = from, *p = from; |
| 243 | |
| 244 | while ((c = *s++) != '\0') { |
| 245 | if (c == '\\' && *s == 'x') { |
| 246 | s++; |
| 247 | c = toupper(*s++); |
| 248 | *p = (c - (isdigit(c) ? '0' : 'A' - 10)) << 4; |
| 249 | c = toupper(*s++); |
| 250 | *p++ |= c - (isdigit(c) ? '0' : 'A' - 10); |
| 251 | continue; |
| 252 | } |
| 253 | *p++ = c; |
| 254 | } |
| 255 | return p - from; |
| 256 | } |
| 257 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 258 | static char * check_special_flags (char * sfs, Node * e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 259 | { |
| 260 | char * p = sfs; |
| 261 | int cont = 1; |
| 262 | |
| 263 | /* special flags */ |
| 264 | while (cont) { |
| 265 | switch (*p) { |
| 266 | case 'P': |
| 267 | p++; |
| 268 | e->flags |= MISC_FMT_PRESERVE_ARGV0; |
| 269 | break; |
| 270 | case 'O': |
| 271 | p++; |
| 272 | e->flags |= MISC_FMT_OPEN_BINARY; |
| 273 | break; |
| 274 | case 'C': |
| 275 | p++; |
| 276 | /* this flags also implies the |
| 277 | open-binary flag */ |
| 278 | e->flags |= (MISC_FMT_CREDENTIALS | |
| 279 | MISC_FMT_OPEN_BINARY); |
| 280 | break; |
| 281 | default: |
| 282 | cont = 0; |
| 283 | } |
| 284 | } |
| 285 | |
| 286 | return p; |
| 287 | } |
| 288 | /* |
| 289 | * This registers a new binary format, it recognises the syntax |
| 290 | * ':name:type:offset:magic:mask:interpreter:flags' |
| 291 | * where the ':' is the IFS, that can be chosen with the first char |
| 292 | */ |
| 293 | static Node *create_entry(const char __user *buffer, size_t count) |
| 294 | { |
| 295 | Node *e; |
| 296 | int memsize, err; |
| 297 | char *buf, *p; |
| 298 | char del; |
| 299 | |
| 300 | /* some sanity checks */ |
| 301 | err = -EINVAL; |
| 302 | if ((count < 11) || (count > 256)) |
| 303 | goto out; |
| 304 | |
| 305 | err = -ENOMEM; |
| 306 | memsize = sizeof(Node) + count + 8; |
Robert P. J. Day | 5cbded5 | 2006-12-13 00:35:56 -0800 | [diff] [blame] | 307 | e = kmalloc(memsize, GFP_USER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 308 | if (!e) |
| 309 | goto out; |
| 310 | |
| 311 | p = buf = (char *)e + sizeof(Node); |
| 312 | |
| 313 | memset(e, 0, sizeof(Node)); |
| 314 | if (copy_from_user(buf, buffer, count)) |
| 315 | goto Efault; |
| 316 | |
| 317 | del = *p++; /* delimeter */ |
| 318 | |
| 319 | memset(buf+count, del, 8); |
| 320 | |
| 321 | e->name = p; |
| 322 | p = strchr(p, del); |
| 323 | if (!p) |
| 324 | goto Einval; |
| 325 | *p++ = '\0'; |
| 326 | if (!e->name[0] || |
| 327 | !strcmp(e->name, ".") || |
| 328 | !strcmp(e->name, "..") || |
| 329 | strchr(e->name, '/')) |
| 330 | goto Einval; |
| 331 | switch (*p++) { |
| 332 | case 'E': e->flags = 1<<Enabled; break; |
| 333 | case 'M': e->flags = (1<<Enabled) | (1<<Magic); break; |
| 334 | default: goto Einval; |
| 335 | } |
| 336 | if (*p++ != del) |
| 337 | goto Einval; |
| 338 | if (test_bit(Magic, &e->flags)) { |
| 339 | char *s = strchr(p, del); |
| 340 | if (!s) |
| 341 | goto Einval; |
| 342 | *s++ = '\0'; |
| 343 | e->offset = simple_strtoul(p, &p, 10); |
| 344 | if (*p++) |
| 345 | goto Einval; |
| 346 | e->magic = p; |
| 347 | p = scanarg(p, del); |
| 348 | if (!p) |
| 349 | goto Einval; |
| 350 | p[-1] = '\0'; |
| 351 | if (!e->magic[0]) |
| 352 | goto Einval; |
| 353 | e->mask = p; |
| 354 | p = scanarg(p, del); |
| 355 | if (!p) |
| 356 | goto Einval; |
| 357 | p[-1] = '\0'; |
| 358 | if (!e->mask[0]) |
| 359 | e->mask = NULL; |
| 360 | e->size = unquote(e->magic); |
| 361 | if (e->mask && unquote(e->mask) != e->size) |
| 362 | goto Einval; |
| 363 | if (e->size + e->offset > BINPRM_BUF_SIZE) |
| 364 | goto Einval; |
| 365 | } else { |
| 366 | p = strchr(p, del); |
| 367 | if (!p) |
| 368 | goto Einval; |
| 369 | *p++ = '\0'; |
| 370 | e->magic = p; |
| 371 | p = strchr(p, del); |
| 372 | if (!p) |
| 373 | goto Einval; |
| 374 | *p++ = '\0'; |
| 375 | if (!e->magic[0] || strchr(e->magic, '/')) |
| 376 | goto Einval; |
| 377 | p = strchr(p, del); |
| 378 | if (!p) |
| 379 | goto Einval; |
| 380 | *p++ = '\0'; |
| 381 | } |
| 382 | e->interpreter = p; |
| 383 | p = strchr(p, del); |
| 384 | if (!p) |
| 385 | goto Einval; |
| 386 | *p++ = '\0'; |
| 387 | if (!e->interpreter[0]) |
| 388 | goto Einval; |
| 389 | |
| 390 | |
| 391 | p = check_special_flags (p, e); |
| 392 | |
| 393 | if (*p == '\n') |
| 394 | p++; |
| 395 | if (p != buf + count) |
| 396 | goto Einval; |
| 397 | return e; |
| 398 | |
| 399 | out: |
| 400 | return ERR_PTR(err); |
| 401 | |
| 402 | Efault: |
| 403 | kfree(e); |
| 404 | return ERR_PTR(-EFAULT); |
| 405 | Einval: |
| 406 | kfree(e); |
| 407 | return ERR_PTR(-EINVAL); |
| 408 | } |
| 409 | |
| 410 | /* |
| 411 | * Set status of entry/binfmt_misc: |
| 412 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc |
| 413 | */ |
| 414 | static int parse_command(const char __user *buffer, size_t count) |
| 415 | { |
| 416 | char s[4]; |
| 417 | |
| 418 | if (!count) |
| 419 | return 0; |
| 420 | if (count > 3) |
| 421 | return -EINVAL; |
| 422 | if (copy_from_user(s, buffer, count)) |
| 423 | return -EFAULT; |
| 424 | if (s[count-1] == '\n') |
| 425 | count--; |
| 426 | if (count == 1 && s[0] == '0') |
| 427 | return 1; |
| 428 | if (count == 1 && s[0] == '1') |
| 429 | return 2; |
| 430 | if (count == 2 && s[0] == '-' && s[1] == '1') |
| 431 | return 3; |
| 432 | return -EINVAL; |
| 433 | } |
| 434 | |
| 435 | /* generic stuff */ |
| 436 | |
| 437 | static void entry_status(Node *e, char *page) |
| 438 | { |
| 439 | char *dp; |
| 440 | char *status = "disabled"; |
| 441 | const char * flags = "flags: "; |
| 442 | |
| 443 | if (test_bit(Enabled, &e->flags)) |
| 444 | status = "enabled"; |
| 445 | |
| 446 | if (!VERBOSE_STATUS) { |
| 447 | sprintf(page, "%s\n", status); |
| 448 | return; |
| 449 | } |
| 450 | |
| 451 | sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); |
| 452 | dp = page + strlen(page); |
| 453 | |
| 454 | /* print the special flags */ |
| 455 | sprintf (dp, "%s", flags); |
| 456 | dp += strlen (flags); |
| 457 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) { |
| 458 | *dp ++ = 'P'; |
| 459 | } |
| 460 | if (e->flags & MISC_FMT_OPEN_BINARY) { |
| 461 | *dp ++ = 'O'; |
| 462 | } |
| 463 | if (e->flags & MISC_FMT_CREDENTIALS) { |
| 464 | *dp ++ = 'C'; |
| 465 | } |
| 466 | *dp ++ = '\n'; |
| 467 | |
| 468 | |
| 469 | if (!test_bit(Magic, &e->flags)) { |
| 470 | sprintf(dp, "extension .%s\n", e->magic); |
| 471 | } else { |
| 472 | int i; |
| 473 | |
| 474 | sprintf(dp, "offset %i\nmagic ", e->offset); |
| 475 | dp = page + strlen(page); |
| 476 | for (i = 0; i < e->size; i++) { |
| 477 | sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); |
| 478 | dp += 2; |
| 479 | } |
| 480 | if (e->mask) { |
| 481 | sprintf(dp, "\nmask "); |
| 482 | dp += 6; |
| 483 | for (i = 0; i < e->size; i++) { |
| 484 | sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); |
| 485 | dp += 2; |
| 486 | } |
| 487 | } |
| 488 | *dp++ = '\n'; |
| 489 | *dp = '\0'; |
| 490 | } |
| 491 | } |
| 492 | |
| 493 | static struct inode *bm_get_inode(struct super_block *sb, int mode) |
| 494 | { |
| 495 | struct inode * inode = new_inode(sb); |
| 496 | |
| 497 | if (inode) { |
Christoph Hellwig | 85fe402 | 2010-10-23 11:19:54 -0400 | [diff] [blame] | 498 | inode->i_ino = get_next_ino(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 499 | inode->i_mode = mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
| 501 | current_fs_time(inode->i_sb); |
| 502 | } |
| 503 | return inode; |
| 504 | } |
| 505 | |
Al Viro | b57922d | 2010-06-07 14:34:48 -0400 | [diff] [blame] | 506 | static void bm_evict_inode(struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | { |
Al Viro | b57922d | 2010-06-07 14:34:48 -0400 | [diff] [blame] | 508 | end_writeback(inode); |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 509 | kfree(inode->i_private); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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) { |
Miklos Szeredi | 6d6b77f | 2011-10-28 14:13:28 +0200 | [diff] [blame] | 525 | drop_nlink(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 537 | Node *e = file->f_path.dentry->d_inode->i_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 538 | ssize_t res; |
| 539 | char *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | |
| 541 | if (!(page = (char*) __get_free_page(GFP_KERNEL))) |
| 542 | return -ENOMEM; |
| 543 | |
| 544 | entry_status(e, page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 545 | |
Akinobu Mita | 6e2c10a | 2008-07-23 21:29:15 -0700 | [diff] [blame] | 546 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
| 547 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | free_page((unsigned long) page); |
| 549 | return res; |
| 550 | } |
| 551 | |
| 552 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, |
| 553 | size_t count, loff_t *ppos) |
| 554 | { |
| 555 | struct dentry *root; |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 556 | Node *e = file->f_path.dentry->d_inode->i_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 557 | int res = parse_command(buffer, count); |
| 558 | |
| 559 | switch (res) { |
| 560 | case 1: clear_bit(Enabled, &e->flags); |
| 561 | break; |
| 562 | case 2: set_bit(Enabled, &e->flags); |
| 563 | break; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 564 | case 3: root = dget(file->f_path.dentry->d_sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 565 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | |
| 567 | kill_node(e); |
| 568 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 569 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 570 | dput(root); |
| 571 | break; |
| 572 | default: return res; |
| 573 | } |
| 574 | return count; |
| 575 | } |
| 576 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 577 | static const struct file_operations bm_entry_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 578 | .read = bm_entry_read, |
| 579 | .write = bm_entry_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 580 | .llseek = default_llseek, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 581 | }; |
| 582 | |
| 583 | /* /register */ |
| 584 | |
| 585 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, |
| 586 | size_t count, loff_t *ppos) |
| 587 | { |
| 588 | Node *e; |
| 589 | struct inode *inode; |
| 590 | struct dentry *root, *dentry; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 591 | struct super_block *sb = file->f_path.dentry->d_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | int err = 0; |
| 593 | |
| 594 | e = create_entry(buffer, count); |
| 595 | |
| 596 | if (IS_ERR(e)) |
| 597 | return PTR_ERR(e); |
| 598 | |
| 599 | root = dget(sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 600 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 601 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
| 602 | err = PTR_ERR(dentry); |
| 603 | if (IS_ERR(dentry)) |
| 604 | goto out; |
| 605 | |
| 606 | err = -EEXIST; |
| 607 | if (dentry->d_inode) |
| 608 | goto out2; |
| 609 | |
| 610 | inode = bm_get_inode(sb, S_IFREG | 0644); |
| 611 | |
| 612 | err = -ENOMEM; |
| 613 | if (!inode) |
| 614 | goto out2; |
| 615 | |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 616 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | if (err) { |
| 618 | iput(inode); |
| 619 | inode = NULL; |
| 620 | goto out2; |
| 621 | } |
| 622 | |
| 623 | e->dentry = dget(dentry); |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 624 | inode->i_private = e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | inode->i_fop = &bm_entry_operations; |
| 626 | |
| 627 | d_instantiate(dentry, inode); |
| 628 | write_lock(&entries_lock); |
| 629 | list_add(&e->list, &entries); |
| 630 | write_unlock(&entries_lock); |
| 631 | |
| 632 | err = 0; |
| 633 | out2: |
| 634 | dput(dentry); |
| 635 | out: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 636 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 637 | dput(root); |
| 638 | |
| 639 | if (err) { |
| 640 | kfree(e); |
| 641 | return -EINVAL; |
| 642 | } |
| 643 | return count; |
| 644 | } |
| 645 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 646 | static const struct file_operations bm_register_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | .write = bm_register_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 648 | .llseek = noop_llseek, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | }; |
| 650 | |
| 651 | /* /status */ |
| 652 | |
| 653 | static ssize_t |
| 654 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
| 655 | { |
Qinghuang Feng | 87113e8 | 2009-01-06 14:41:38 -0800 | [diff] [blame] | 656 | char *s = enabled ? "enabled\n" : "disabled\n"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | |
Akinobu Mita | 92f4c70 | 2007-05-09 02:33:32 -0700 | [diff] [blame] | 658 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | } |
| 660 | |
| 661 | static ssize_t bm_status_write(struct file * file, const char __user * buffer, |
| 662 | size_t count, loff_t *ppos) |
| 663 | { |
| 664 | int res = parse_command(buffer, count); |
| 665 | struct dentry *root; |
| 666 | |
| 667 | switch (res) { |
| 668 | case 1: enabled = 0; break; |
| 669 | case 2: enabled = 1; break; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 670 | case 3: root = dget(file->f_path.dentry->d_sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 671 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | |
| 673 | while (!list_empty(&entries)) |
| 674 | kill_node(list_entry(entries.next, Node, list)); |
| 675 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 676 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | dput(root); |
| 678 | default: return res; |
| 679 | } |
| 680 | return count; |
| 681 | } |
| 682 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 683 | static const struct file_operations bm_status_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | .read = bm_status_read, |
| 685 | .write = bm_status_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 686 | .llseek = default_llseek, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | }; |
| 688 | |
| 689 | /* Superblock handling */ |
| 690 | |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 691 | static const struct super_operations s_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 692 | .statfs = simple_statfs, |
Al Viro | b57922d | 2010-06-07 14:34:48 -0400 | [diff] [blame] | 693 | .evict_inode = bm_evict_inode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | }; |
| 695 | |
| 696 | static int bm_fill_super(struct super_block * sb, void * data, int silent) |
| 697 | { |
| 698 | static struct tree_descr bm_files[] = { |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 699 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
| 700 | [3] = {"register", &bm_register_operations, S_IWUSR}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 701 | /* last one */ {""} |
| 702 | }; |
Muthu Kumar | b502bd1 | 2012-03-23 15:01:50 -0700 | [diff] [blame^] | 703 | int err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | if (!err) |
| 705 | sb->s_op = &s_ops; |
| 706 | return err; |
| 707 | } |
| 708 | |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 709 | static struct dentry *bm_mount(struct file_system_type *fs_type, |
| 710 | int flags, const char *dev_name, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 711 | { |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 712 | return mount_single(fs_type, flags, data, bm_fill_super); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | } |
| 714 | |
| 715 | static struct linux_binfmt misc_format = { |
| 716 | .module = THIS_MODULE, |
| 717 | .load_binary = load_misc_binary, |
| 718 | }; |
| 719 | |
| 720 | static struct file_system_type bm_fs_type = { |
| 721 | .owner = THIS_MODULE, |
| 722 | .name = "binfmt_misc", |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 723 | .mount = bm_mount, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 724 | .kill_sb = kill_litter_super, |
| 725 | }; |
| 726 | |
| 727 | static int __init init_misc_binfmt(void) |
| 728 | { |
| 729 | int err = register_filesystem(&bm_fs_type); |
Al Viro | 8fc3dc5 | 2012-03-17 03:05:16 -0400 | [diff] [blame] | 730 | if (!err) |
| 731 | insert_binfmt(&misc_format); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 732 | return err; |
| 733 | } |
| 734 | |
| 735 | static void __exit exit_misc_binfmt(void) |
| 736 | { |
| 737 | unregister_binfmt(&misc_format); |
| 738 | unregister_filesystem(&bm_fs_type); |
| 739 | } |
| 740 | |
| 741 | core_initcall(init_misc_binfmt); |
| 742 | module_exit(exit_misc_binfmt); |
| 743 | MODULE_LICENSE("GPL"); |