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> |
Andy Shevchenko | 8d82e18 | 2013-04-30 15:27:33 -0700 | [diff] [blame] | 26 | #include <linux/string_helpers.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/file.h> |
| 28 | #include <linux/pagemap.h> |
| 29 | #include <linux/namei.h> |
| 30 | #include <linux/mount.h> |
| 31 | #include <linux/syscalls.h> |
Akinobu Mita | 6e2c10a | 2008-07-23 21:29:15 -0700 | [diff] [blame] | 32 | #include <linux/fs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | |
| 34 | #include <asm/uaccess.h> |
| 35 | |
| 36 | enum { |
| 37 | VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ |
| 38 | }; |
| 39 | |
| 40 | static LIST_HEAD(entries); |
| 41 | static int enabled = 1; |
| 42 | |
| 43 | enum {Enabled, Magic}; |
| 44 | #define MISC_FMT_PRESERVE_ARGV0 (1<<31) |
| 45 | #define MISC_FMT_OPEN_BINARY (1<<30) |
| 46 | #define MISC_FMT_CREDENTIALS (1<<29) |
| 47 | |
| 48 | typedef struct { |
| 49 | struct list_head list; |
| 50 | unsigned long flags; /* type, status, etc. */ |
| 51 | int offset; /* offset of magic */ |
| 52 | int size; /* size of magic/mask */ |
| 53 | char *magic; /* magic or filename extension */ |
| 54 | char *mask; /* mask, NULL for exact match */ |
| 55 | char *interpreter; /* filename of interpreter */ |
| 56 | char *name; |
| 57 | struct dentry *dentry; |
| 58 | } Node; |
| 59 | |
| 60 | static DEFINE_RWLOCK(entries_lock); |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 61 | static struct file_system_type bm_fs_type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | static struct vfsmount *bm_mnt; |
| 63 | static int entry_count; |
| 64 | |
Mike Frysinger | bbaecc0 | 2014-10-13 15:52:03 -0700 | [diff] [blame] | 65 | /* |
| 66 | * Max length of the register string. Determined by: |
| 67 | * - 7 delimiters |
| 68 | * - name: ~50 bytes |
| 69 | * - type: 1 byte |
| 70 | * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE) |
| 71 | * - magic: 128 bytes (512 in escaped form) |
| 72 | * - mask: 128 bytes (512 in escaped form) |
| 73 | * - interp: ~50 bytes |
| 74 | * - flags: 5 bytes |
| 75 | * Round that up a bit, and then back off to hold the internal data |
| 76 | * (like struct Node). |
| 77 | */ |
| 78 | #define MAX_REGISTER_LENGTH 1920 |
| 79 | |
| 80 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | * Check if we support the binfmt |
| 82 | * if we do, return the node, else NULL |
| 83 | * locking is done in load_misc_binary |
| 84 | */ |
| 85 | static Node *check_file(struct linux_binprm *bprm) |
| 86 | { |
| 87 | char *p = strrchr(bprm->interp, '.'); |
| 88 | struct list_head *l; |
| 89 | |
| 90 | list_for_each(l, &entries) { |
| 91 | Node *e = list_entry(l, Node, list); |
| 92 | char *s; |
| 93 | int j; |
| 94 | |
| 95 | if (!test_bit(Enabled, &e->flags)) |
| 96 | continue; |
| 97 | |
| 98 | if (!test_bit(Magic, &e->flags)) { |
| 99 | if (p && !strcmp(e->magic, p + 1)) |
| 100 | return e; |
| 101 | continue; |
| 102 | } |
| 103 | |
| 104 | s = bprm->buf + e->offset; |
| 105 | if (e->mask) { |
| 106 | for (j = 0; j < e->size; j++) |
| 107 | if ((*s++ ^ e->magic[j]) & e->mask[j]) |
| 108 | break; |
| 109 | } else { |
| 110 | for (j = 0; j < e->size; j++) |
| 111 | if ((*s++ ^ e->magic[j])) |
| 112 | break; |
| 113 | } |
| 114 | if (j == e->size) |
| 115 | return e; |
| 116 | } |
| 117 | return NULL; |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * the loader itself |
| 122 | */ |
Al Viro | 71613c3 | 2012-10-20 22:00:48 -0400 | [diff] [blame] | 123 | static int load_misc_binary(struct linux_binprm *bprm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | { |
| 125 | Node *fmt; |
| 126 | struct file * interp_file = NULL; |
| 127 | char iname[BINPRM_BUF_SIZE]; |
David Howells | d762746 | 2010-08-17 23:52:56 +0100 | [diff] [blame] | 128 | const char *iname_addr = iname; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | int retval; |
| 130 | int fd_binary = -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | |
| 132 | retval = -ENOEXEC; |
| 133 | if (!enabled) |
| 134 | goto _ret; |
| 135 | |
| 136 | /* to keep locking time low, we copy the interpreter string */ |
| 137 | read_lock(&entries_lock); |
| 138 | fmt = check_file(bprm); |
| 139 | if (fmt) |
| 140 | strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); |
| 141 | read_unlock(&entries_lock); |
| 142 | if (!fmt) |
| 143 | goto _ret; |
| 144 | |
| 145 | if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 146 | retval = remove_arg_zero(bprm); |
| 147 | if (retval) |
| 148 | goto _ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | } |
| 150 | |
| 151 | if (fmt->flags & MISC_FMT_OPEN_BINARY) { |
| 152 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | /* if the binary should be opened on behalf of the |
| 154 | * interpreter than keep it open and assign descriptor |
| 155 | * to it */ |
Yann Droneaud | c6cb898 | 2014-12-10 15:45:42 -0800 | [diff] [blame^] | 156 | fd_binary = get_unused_fd_flags(0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | if (fd_binary < 0) { |
| 158 | retval = fd_binary; |
Al Viro | fd8328b | 2008-04-22 05:11:59 -0400 | [diff] [blame] | 159 | goto _ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | } |
| 161 | fd_install(fd_binary, bprm->file); |
| 162 | |
| 163 | /* if the binary is not readable than enforce mm->dumpable=0 |
| 164 | regardless of the interpreter's permissions */ |
Al Viro | 1b5d783 | 2011-06-19 12:49:47 -0400 | [diff] [blame] | 165 | would_dump(bprm, bprm->file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | |
| 167 | allow_write_access(bprm->file); |
| 168 | bprm->file = NULL; |
| 169 | |
| 170 | /* mark the bprm that fd should be passed to interp */ |
| 171 | bprm->interp_flags |= BINPRM_FLAGS_EXECFD; |
| 172 | bprm->interp_data = fd_binary; |
| 173 | |
| 174 | } else { |
| 175 | allow_write_access(bprm->file); |
| 176 | fput(bprm->file); |
| 177 | bprm->file = NULL; |
| 178 | } |
| 179 | /* make argv[1] be the path to the binary */ |
| 180 | retval = copy_strings_kernel (1, &bprm->interp, bprm); |
| 181 | if (retval < 0) |
| 182 | goto _error; |
| 183 | bprm->argc++; |
| 184 | |
| 185 | /* add the interp as argv[0] */ |
| 186 | retval = copy_strings_kernel (1, &iname_addr, bprm); |
| 187 | if (retval < 0) |
| 188 | goto _error; |
| 189 | bprm->argc ++; |
| 190 | |
Kees Cook | b66c598 | 2012-12-20 15:05:16 -0800 | [diff] [blame] | 191 | /* Update interp in case binfmt_script needs it. */ |
| 192 | retval = bprm_change_interp(iname, bprm); |
| 193 | if (retval < 0) |
| 194 | goto _error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | |
| 196 | interp_file = open_exec (iname); |
| 197 | retval = PTR_ERR (interp_file); |
| 198 | if (IS_ERR (interp_file)) |
| 199 | goto _error; |
| 200 | |
| 201 | bprm->file = interp_file; |
| 202 | if (fmt->flags & MISC_FMT_CREDENTIALS) { |
| 203 | /* |
| 204 | * No need to call prepare_binprm(), it's already been |
| 205 | * done. bprm->buf is stale, update from interp_file. |
| 206 | */ |
| 207 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
| 208 | retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); |
| 209 | } else |
| 210 | retval = prepare_binprm (bprm); |
| 211 | |
| 212 | if (retval < 0) |
| 213 | goto _error; |
| 214 | |
Al Viro | 3c456bf | 2012-10-20 21:53:31 -0400 | [diff] [blame] | 215 | retval = search_binary_handler(bprm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | if (retval < 0) |
| 217 | goto _error; |
| 218 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | _ret: |
| 220 | return retval; |
| 221 | _error: |
| 222 | if (fd_binary > 0) |
| 223 | sys_close(fd_binary); |
| 224 | bprm->interp_flags = 0; |
| 225 | bprm->interp_data = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | goto _ret; |
| 227 | } |
| 228 | |
| 229 | /* Command parsers */ |
| 230 | |
| 231 | /* |
| 232 | * parses and copies one argument enclosed in del from *sp to *dp, |
| 233 | * recognising the \x special. |
| 234 | * returns pointer to the copied argument or NULL in case of an |
| 235 | * error (and sets err) or null argument length. |
| 236 | */ |
| 237 | static char *scanarg(char *s, char del) |
| 238 | { |
| 239 | char c; |
| 240 | |
| 241 | while ((c = *s++) != del) { |
| 242 | if (c == '\\' && *s == 'x') { |
| 243 | s++; |
| 244 | if (!isxdigit(*s++)) |
| 245 | return NULL; |
| 246 | if (!isxdigit(*s++)) |
| 247 | return NULL; |
| 248 | } |
| 249 | } |
| 250 | return s; |
| 251 | } |
| 252 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 253 | static char * check_special_flags (char * sfs, Node * e) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | { |
| 255 | char * p = sfs; |
| 256 | int cont = 1; |
| 257 | |
| 258 | /* special flags */ |
| 259 | while (cont) { |
| 260 | switch (*p) { |
| 261 | case 'P': |
| 262 | p++; |
| 263 | e->flags |= MISC_FMT_PRESERVE_ARGV0; |
| 264 | break; |
| 265 | case 'O': |
| 266 | p++; |
| 267 | e->flags |= MISC_FMT_OPEN_BINARY; |
| 268 | break; |
| 269 | case 'C': |
| 270 | p++; |
| 271 | /* this flags also implies the |
| 272 | open-binary flag */ |
| 273 | e->flags |= (MISC_FMT_CREDENTIALS | |
| 274 | MISC_FMT_OPEN_BINARY); |
| 275 | break; |
| 276 | default: |
| 277 | cont = 0; |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | return p; |
| 282 | } |
| 283 | /* |
| 284 | * This registers a new binary format, it recognises the syntax |
| 285 | * ':name:type:offset:magic:mask:interpreter:flags' |
| 286 | * where the ':' is the IFS, that can be chosen with the first char |
| 287 | */ |
| 288 | static Node *create_entry(const char __user *buffer, size_t count) |
| 289 | { |
| 290 | Node *e; |
| 291 | int memsize, err; |
| 292 | char *buf, *p; |
| 293 | char del; |
| 294 | |
| 295 | /* some sanity checks */ |
| 296 | err = -EINVAL; |
Mike Frysinger | bbaecc0 | 2014-10-13 15:52:03 -0700 | [diff] [blame] | 297 | if ((count < 11) || (count > MAX_REGISTER_LENGTH)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | goto out; |
| 299 | |
| 300 | err = -ENOMEM; |
| 301 | memsize = sizeof(Node) + count + 8; |
Robert P. J. Day | 5cbded5 | 2006-12-13 00:35:56 -0800 | [diff] [blame] | 302 | e = kmalloc(memsize, GFP_USER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 303 | if (!e) |
| 304 | goto out; |
| 305 | |
| 306 | p = buf = (char *)e + sizeof(Node); |
| 307 | |
| 308 | memset(e, 0, sizeof(Node)); |
| 309 | if (copy_from_user(buf, buffer, count)) |
| 310 | goto Efault; |
| 311 | |
| 312 | del = *p++; /* delimeter */ |
| 313 | |
| 314 | memset(buf+count, del, 8); |
| 315 | |
| 316 | e->name = p; |
| 317 | p = strchr(p, del); |
| 318 | if (!p) |
| 319 | goto Einval; |
| 320 | *p++ = '\0'; |
| 321 | if (!e->name[0] || |
| 322 | !strcmp(e->name, ".") || |
| 323 | !strcmp(e->name, "..") || |
| 324 | strchr(e->name, '/')) |
| 325 | goto Einval; |
| 326 | switch (*p++) { |
| 327 | case 'E': e->flags = 1<<Enabled; break; |
| 328 | case 'M': e->flags = (1<<Enabled) | (1<<Magic); break; |
| 329 | default: goto Einval; |
| 330 | } |
| 331 | if (*p++ != del) |
| 332 | goto Einval; |
| 333 | if (test_bit(Magic, &e->flags)) { |
| 334 | char *s = strchr(p, del); |
| 335 | if (!s) |
| 336 | goto Einval; |
| 337 | *s++ = '\0'; |
| 338 | e->offset = simple_strtoul(p, &p, 10); |
| 339 | if (*p++) |
| 340 | goto Einval; |
| 341 | e->magic = p; |
| 342 | p = scanarg(p, del); |
| 343 | if (!p) |
| 344 | goto Einval; |
| 345 | p[-1] = '\0'; |
| 346 | if (!e->magic[0]) |
| 347 | goto Einval; |
| 348 | e->mask = p; |
| 349 | p = scanarg(p, del); |
| 350 | if (!p) |
| 351 | goto Einval; |
| 352 | p[-1] = '\0'; |
| 353 | if (!e->mask[0]) |
| 354 | e->mask = NULL; |
Andy Shevchenko | 8d82e18 | 2013-04-30 15:27:33 -0700 | [diff] [blame] | 355 | e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); |
| 356 | if (e->mask && |
| 357 | string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | goto Einval; |
| 359 | if (e->size + e->offset > BINPRM_BUF_SIZE) |
| 360 | goto Einval; |
| 361 | } else { |
| 362 | p = strchr(p, del); |
| 363 | if (!p) |
| 364 | goto Einval; |
| 365 | *p++ = '\0'; |
| 366 | e->magic = p; |
| 367 | p = strchr(p, del); |
| 368 | if (!p) |
| 369 | goto Einval; |
| 370 | *p++ = '\0'; |
| 371 | if (!e->magic[0] || strchr(e->magic, '/')) |
| 372 | goto Einval; |
| 373 | p = strchr(p, del); |
| 374 | if (!p) |
| 375 | goto Einval; |
| 376 | *p++ = '\0'; |
| 377 | } |
| 378 | e->interpreter = p; |
| 379 | p = strchr(p, del); |
| 380 | if (!p) |
| 381 | goto Einval; |
| 382 | *p++ = '\0'; |
| 383 | if (!e->interpreter[0]) |
| 384 | goto Einval; |
| 385 | |
| 386 | |
| 387 | p = check_special_flags (p, e); |
| 388 | |
| 389 | if (*p == '\n') |
| 390 | p++; |
| 391 | if (p != buf + count) |
| 392 | goto Einval; |
| 393 | return e; |
| 394 | |
| 395 | out: |
| 396 | return ERR_PTR(err); |
| 397 | |
| 398 | Efault: |
| 399 | kfree(e); |
| 400 | return ERR_PTR(-EFAULT); |
| 401 | Einval: |
| 402 | kfree(e); |
| 403 | return ERR_PTR(-EINVAL); |
| 404 | } |
| 405 | |
| 406 | /* |
| 407 | * Set status of entry/binfmt_misc: |
| 408 | * '1' enables, '0' disables and '-1' clears entry/binfmt_misc |
| 409 | */ |
| 410 | static int parse_command(const char __user *buffer, size_t count) |
| 411 | { |
| 412 | char s[4]; |
| 413 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | if (count > 3) |
| 415 | return -EINVAL; |
| 416 | if (copy_from_user(s, buffer, count)) |
| 417 | return -EFAULT; |
Arnd Bergmann | de8288b | 2014-10-13 15:52:08 -0700 | [diff] [blame] | 418 | if (!count) |
| 419 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | if (s[count-1] == '\n') |
| 421 | count--; |
| 422 | if (count == 1 && s[0] == '0') |
| 423 | return 1; |
| 424 | if (count == 1 && s[0] == '1') |
| 425 | return 2; |
| 426 | if (count == 2 && s[0] == '-' && s[1] == '1') |
| 427 | return 3; |
| 428 | return -EINVAL; |
| 429 | } |
| 430 | |
| 431 | /* generic stuff */ |
| 432 | |
| 433 | static void entry_status(Node *e, char *page) |
| 434 | { |
| 435 | char *dp; |
| 436 | char *status = "disabled"; |
| 437 | const char * flags = "flags: "; |
| 438 | |
| 439 | if (test_bit(Enabled, &e->flags)) |
| 440 | status = "enabled"; |
| 441 | |
| 442 | if (!VERBOSE_STATUS) { |
| 443 | sprintf(page, "%s\n", status); |
| 444 | return; |
| 445 | } |
| 446 | |
| 447 | sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); |
| 448 | dp = page + strlen(page); |
| 449 | |
| 450 | /* print the special flags */ |
| 451 | sprintf (dp, "%s", flags); |
| 452 | dp += strlen (flags); |
| 453 | if (e->flags & MISC_FMT_PRESERVE_ARGV0) { |
| 454 | *dp ++ = 'P'; |
| 455 | } |
| 456 | if (e->flags & MISC_FMT_OPEN_BINARY) { |
| 457 | *dp ++ = 'O'; |
| 458 | } |
| 459 | if (e->flags & MISC_FMT_CREDENTIALS) { |
| 460 | *dp ++ = 'C'; |
| 461 | } |
| 462 | *dp ++ = '\n'; |
| 463 | |
| 464 | |
| 465 | if (!test_bit(Magic, &e->flags)) { |
| 466 | sprintf(dp, "extension .%s\n", e->magic); |
| 467 | } else { |
| 468 | int i; |
| 469 | |
| 470 | sprintf(dp, "offset %i\nmagic ", e->offset); |
| 471 | dp = page + strlen(page); |
| 472 | for (i = 0; i < e->size; i++) { |
| 473 | sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); |
| 474 | dp += 2; |
| 475 | } |
| 476 | if (e->mask) { |
| 477 | sprintf(dp, "\nmask "); |
| 478 | dp += 6; |
| 479 | for (i = 0; i < e->size; i++) { |
| 480 | sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); |
| 481 | dp += 2; |
| 482 | } |
| 483 | } |
| 484 | *dp++ = '\n'; |
| 485 | *dp = '\0'; |
| 486 | } |
| 487 | } |
| 488 | |
| 489 | static struct inode *bm_get_inode(struct super_block *sb, int mode) |
| 490 | { |
| 491 | struct inode * inode = new_inode(sb); |
| 492 | |
| 493 | if (inode) { |
Christoph Hellwig | 85fe402 | 2010-10-23 11:19:54 -0400 | [diff] [blame] | 494 | inode->i_ino = get_next_ino(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | inode->i_mode = mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | inode->i_atime = inode->i_mtime = inode->i_ctime = |
| 497 | current_fs_time(inode->i_sb); |
| 498 | } |
| 499 | return inode; |
| 500 | } |
| 501 | |
Al Viro | b57922d | 2010-06-07 14:34:48 -0400 | [diff] [blame] | 502 | static void bm_evict_inode(struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 503 | { |
Jan Kara | dbd5768 | 2012-05-03 14:48:02 +0200 | [diff] [blame] | 504 | clear_inode(inode); |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 505 | kfree(inode->i_private); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | } |
| 507 | |
| 508 | static void kill_node(Node *e) |
| 509 | { |
| 510 | struct dentry *dentry; |
| 511 | |
| 512 | write_lock(&entries_lock); |
| 513 | dentry = e->dentry; |
| 514 | if (dentry) { |
| 515 | list_del_init(&e->list); |
| 516 | e->dentry = NULL; |
| 517 | } |
| 518 | write_unlock(&entries_lock); |
| 519 | |
| 520 | if (dentry) { |
Miklos Szeredi | 6d6b77f | 2011-10-28 14:13:28 +0200 | [diff] [blame] | 521 | drop_nlink(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | d_drop(dentry); |
| 523 | dput(dentry); |
| 524 | simple_release_fs(&bm_mnt, &entry_count); |
| 525 | } |
| 526 | } |
| 527 | |
| 528 | /* /<entry> */ |
| 529 | |
| 530 | static ssize_t |
| 531 | bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos) |
| 532 | { |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 533 | Node *e = file_inode(file)->i_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 534 | ssize_t res; |
| 535 | char *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | |
| 537 | if (!(page = (char*) __get_free_page(GFP_KERNEL))) |
| 538 | return -ENOMEM; |
| 539 | |
| 540 | entry_status(e, page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | |
Akinobu Mita | 6e2c10a | 2008-07-23 21:29:15 -0700 | [diff] [blame] | 542 | res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); |
| 543 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | free_page((unsigned long) page); |
| 545 | return res; |
| 546 | } |
| 547 | |
| 548 | static ssize_t bm_entry_write(struct file *file, const char __user *buffer, |
| 549 | size_t count, loff_t *ppos) |
| 550 | { |
| 551 | struct dentry *root; |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 552 | Node *e = file_inode(file)->i_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | int res = parse_command(buffer, count); |
| 554 | |
| 555 | switch (res) { |
| 556 | case 1: clear_bit(Enabled, &e->flags); |
| 557 | break; |
| 558 | case 2: set_bit(Enabled, &e->flags); |
| 559 | break; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 560 | case 3: root = dget(file->f_path.dentry->d_sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 561 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | |
| 563 | kill_node(e); |
| 564 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 565 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | dput(root); |
| 567 | break; |
| 568 | default: return res; |
| 569 | } |
| 570 | return count; |
| 571 | } |
| 572 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 573 | static const struct file_operations bm_entry_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | .read = bm_entry_read, |
| 575 | .write = bm_entry_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 576 | .llseek = default_llseek, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | }; |
| 578 | |
| 579 | /* /register */ |
| 580 | |
| 581 | static ssize_t bm_register_write(struct file *file, const char __user *buffer, |
| 582 | size_t count, loff_t *ppos) |
| 583 | { |
| 584 | Node *e; |
| 585 | struct inode *inode; |
| 586 | struct dentry *root, *dentry; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 587 | struct super_block *sb = file->f_path.dentry->d_sb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 588 | int err = 0; |
| 589 | |
| 590 | e = create_entry(buffer, count); |
| 591 | |
| 592 | if (IS_ERR(e)) |
| 593 | return PTR_ERR(e); |
| 594 | |
| 595 | root = dget(sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 596 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 597 | dentry = lookup_one_len(e->name, root, strlen(e->name)); |
| 598 | err = PTR_ERR(dentry); |
| 599 | if (IS_ERR(dentry)) |
| 600 | goto out; |
| 601 | |
| 602 | err = -EEXIST; |
| 603 | if (dentry->d_inode) |
| 604 | goto out2; |
| 605 | |
| 606 | inode = bm_get_inode(sb, S_IFREG | 0644); |
| 607 | |
| 608 | err = -ENOMEM; |
| 609 | if (!inode) |
| 610 | goto out2; |
| 611 | |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 612 | err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 613 | if (err) { |
| 614 | iput(inode); |
| 615 | inode = NULL; |
| 616 | goto out2; |
| 617 | } |
| 618 | |
| 619 | e->dentry = dget(dentry); |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 620 | inode->i_private = e; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 621 | inode->i_fop = &bm_entry_operations; |
| 622 | |
| 623 | d_instantiate(dentry, inode); |
| 624 | write_lock(&entries_lock); |
| 625 | list_add(&e->list, &entries); |
| 626 | write_unlock(&entries_lock); |
| 627 | |
| 628 | err = 0; |
| 629 | out2: |
| 630 | dput(dentry); |
| 631 | out: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 632 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | dput(root); |
| 634 | |
| 635 | if (err) { |
| 636 | kfree(e); |
| 637 | return -EINVAL; |
| 638 | } |
| 639 | return count; |
| 640 | } |
| 641 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 642 | static const struct file_operations bm_register_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | .write = bm_register_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 644 | .llseek = noop_llseek, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | }; |
| 646 | |
| 647 | /* /status */ |
| 648 | |
| 649 | static ssize_t |
| 650 | bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) |
| 651 | { |
Qinghuang Feng | 87113e8 | 2009-01-06 14:41:38 -0800 | [diff] [blame] | 652 | char *s = enabled ? "enabled\n" : "disabled\n"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | |
Akinobu Mita | 92f4c70 | 2007-05-09 02:33:32 -0700 | [diff] [blame] | 654 | return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | } |
| 656 | |
| 657 | static ssize_t bm_status_write(struct file * file, const char __user * buffer, |
| 658 | size_t count, loff_t *ppos) |
| 659 | { |
| 660 | int res = parse_command(buffer, count); |
| 661 | struct dentry *root; |
| 662 | |
| 663 | switch (res) { |
| 664 | case 1: enabled = 0; break; |
| 665 | case 2: enabled = 1; break; |
Al Viro | d8c9584 | 2011-12-07 18:16:57 -0500 | [diff] [blame] | 666 | case 3: root = dget(file->f_path.dentry->d_sb->s_root); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 667 | mutex_lock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | |
| 669 | while (!list_empty(&entries)) |
| 670 | kill_node(list_entry(entries.next, Node, list)); |
| 671 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 672 | mutex_unlock(&root->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 673 | dput(root); |
Luis Henriques | b003f96 | 2014-04-03 14:49:34 -0700 | [diff] [blame] | 674 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | default: return res; |
| 676 | } |
| 677 | return count; |
| 678 | } |
| 679 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 680 | static const struct file_operations bm_status_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | .read = bm_status_read, |
| 682 | .write = bm_status_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 683 | .llseek = default_llseek, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | }; |
| 685 | |
| 686 | /* Superblock handling */ |
| 687 | |
Josef 'Jeff' Sipek | ee9b6d6 | 2007-02-12 00:55:41 -0800 | [diff] [blame] | 688 | static const struct super_operations s_ops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 689 | .statfs = simple_statfs, |
Al Viro | b57922d | 2010-06-07 14:34:48 -0400 | [diff] [blame] | 690 | .evict_inode = bm_evict_inode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 691 | }; |
| 692 | |
| 693 | static int bm_fill_super(struct super_block * sb, void * data, int silent) |
| 694 | { |
| 695 | static struct tree_descr bm_files[] = { |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 696 | [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, |
| 697 | [3] = {"register", &bm_register_operations, S_IWUSR}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 698 | /* last one */ {""} |
| 699 | }; |
Muthu Kumar | b502bd1 | 2012-03-23 15:01:50 -0700 | [diff] [blame] | 700 | int err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 701 | if (!err) |
| 702 | sb->s_op = &s_ops; |
| 703 | return err; |
| 704 | } |
| 705 | |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 706 | static struct dentry *bm_mount(struct file_system_type *fs_type, |
| 707 | int flags, const char *dev_name, void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 708 | { |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 709 | return mount_single(fs_type, flags, data, bm_fill_super); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 710 | } |
| 711 | |
| 712 | static struct linux_binfmt misc_format = { |
| 713 | .module = THIS_MODULE, |
| 714 | .load_binary = load_misc_binary, |
| 715 | }; |
| 716 | |
| 717 | static struct file_system_type bm_fs_type = { |
| 718 | .owner = THIS_MODULE, |
| 719 | .name = "binfmt_misc", |
Al Viro | fc14f2f | 2010-07-25 01:48:30 +0400 | [diff] [blame] | 720 | .mount = bm_mount, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | .kill_sb = kill_litter_super, |
| 722 | }; |
Eric W. Biederman | 7f78e03 | 2013-03-02 19:39:14 -0800 | [diff] [blame] | 723 | MODULE_ALIAS_FS("binfmt_misc"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 724 | |
| 725 | static int __init init_misc_binfmt(void) |
| 726 | { |
| 727 | int err = register_filesystem(&bm_fs_type); |
Al Viro | 8fc3dc5 | 2012-03-17 03:05:16 -0400 | [diff] [blame] | 728 | if (!err) |
| 729 | insert_binfmt(&misc_format); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 730 | return err; |
| 731 | } |
| 732 | |
| 733 | static void __exit exit_misc_binfmt(void) |
| 734 | { |
| 735 | unregister_binfmt(&misc_format); |
| 736 | unregister_filesystem(&bm_fs_type); |
| 737 | } |
| 738 | |
| 739 | core_initcall(init_misc_binfmt); |
| 740 | module_exit(exit_misc_binfmt); |
| 741 | MODULE_LICENSE("GPL"); |