fs/read_write.c

   1 /*
   2  *  linux/fs/read_write.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/slab.h>
   8 #include <linux/stat.h>
   9 #include <linux/fcntl.h>
  10 #include <linux/file.h>
  11 #include <linux/uio.h>
  12 #include <linux/smp_lock.h>
  13 #include <linux/fsnotify.h>
  14 #include <linux/security.h>
  15 #include <linux/module.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/pagemap.h>
  18 #include "read_write.h"
  19
  20 #include <asm/uaccess.h>
  21 #include <asm/unistd.h>
  22
  23 const struct file_operations generic_ro_fops = {
  24         .llseek         = generic_file_llseek,
  25         .read           = do_sync_read,
  26         .aio_read       = generic_file_aio_read,
  27         .mmap           = generic_file_readonly_mmap,
  28         .sendfile       = generic_file_sendfile,
  29 };
  30
  31 EXPORT_SYMBOL(generic_ro_fops);
  32
  33 loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
  34 {
  35         long long retval;
  36         struct inode *inode = file->f_mapping->host;
  37
  38         mutex_lock(&inode->i_mutex);
  39         switch (origin) {
  40                 case 2:
  41                         offset += inode->i_size;
  42                         break;
  43                 case 1:
  44                         offset += file->f_pos;
  45         }
  46         retval = -EINVAL;
  47         if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
  48                 if (offset != file->f_pos) {
  49                         file->f_pos = offset;
  50                         file->f_version = 0;
  51                 }
  52                 retval = offset;
  53         }
  54         mutex_unlock(&inode->i_mutex);
  55         return retval;
  56 }
  57
  58 EXPORT_SYMBOL(generic_file_llseek);
  59
  60 loff_t remote_llseek(struct file *file, loff_t offset, int origin)
  61 {
  62         long long retval;
  63
  64         lock_kernel();
  65         switch (origin) {
  66                 case 2:
  67                         offset += i_size_read(file->f_path.dentry->d_inode);
  68                         break;
  69                 case 1:
  70                         offset += file->f_pos;
  71         }
  72         retval = -EINVAL;
  73         if (offset>=0 && offset<=file->f_path.dentry->d_inode->i_sb->s_maxbytes) {
  74                 if (offset != file->f_pos) {
  75                         file->f_pos = offset;
  76                         file->f_version = 0;
  77                 }
  78                 retval = offset;
  79         }
  80         unlock_kernel();
  81         return retval;
  82 }
  83 EXPORT_SYMBOL(remote_llseek);
  84
  85 loff_t no_llseek(struct file *file, loff_t offset, int origin)
  86 {
  87         return -ESPIPE;
  88 }
  89 EXPORT_SYMBOL(no_llseek);
  90
  91 loff_t default_llseek(struct file *file, loff_t offset, int origin)
  92 {
  93         long long retval;
  94
  95         lock_kernel();
  96         switch (origin) {
  97                 case 2:
  98                         offset += i_size_read(file->f_path.dentry->d_inode);
  99                         break;
 100                 case 1:
 101                         offset += file->f_pos;
 102         }
 103         retval = -EINVAL;
 104         if (offset >= 0) {
 105                 if (offset != file->f_pos) {
 106                         file->f_pos = offset;
 107                         file->f_version = 0;
 108                 }
 109                 retval = offset;
 110         }
 111         unlock_kernel();
 112         return retval;
 113 }
 114 EXPORT_SYMBOL(default_llseek);
 115
 116 loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
 117 {
 118         loff_t (*fn)(struct file *, loff_t, int);
 119
 120         fn = no_llseek;
 121         if (file->f_mode & FMODE_LSEEK) {
 122                 fn = default_llseek;
 123                 if (file->f_op && file->f_op->llseek)
 124                         fn = file->f_op->llseek;
 125         }
 126         return fn(file, offset, origin);
 127 }
 128 EXPORT_SYMBOL(vfs_llseek);
 129
 130 asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
 131 {
 132         off_t retval;
 133         struct file * file;
 134         int fput_needed;
 135
 136         retval = -EBADF;
 137         file = fget_light(fd, &fput_needed);
 138         if (!file)
 139                 goto bad;
 140
 141         retval = -EINVAL;
 142         if (origin <= 2) {
 143                 loff_t res = vfs_llseek(file, offset, origin);
 144                 retval = res;
 145                 if (res != (loff_t)retval)
 146                         retval = -EOVERFLOW;    /* LFS: should only happen on 32 bit platforms */
 147         }
 148         fput_light(file, fput_needed);
 149 bad:
 150         return retval;
 151 }
 152
 153 #ifdef __ARCH_WANT_SYS_LLSEEK
 154 asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
 155                            unsigned long offset_low, loff_t __user * result,
 156                            unsigned int origin)
 157 {
 158         int retval;
 159         struct file * file;
 160         loff_t offset;
 161         int fput_needed;
 162
 163         retval = -EBADF;
 164         file = fget_light(fd, &fput_needed);
 165         if (!file)
 166                 goto bad;
 167
 168         retval = -EINVAL;
 169         if (origin > 2)
 170                 goto out_putf;
 171
 172         offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
 173                         origin);
 174
 175         retval = (int)offset;
 176         if (offset >= 0) {
 177                 retval = -EFAULT;
 178                 if (!copy_to_user(result, &offset, sizeof(offset)))
 179                         retval = 0;
 180         }
 181 out_putf:
 182         fput_light(file, fput_needed);
 183 bad:
 184         return retval;
 185 }
 186 #endif
 187
 188 /*
 189  * rw_verify_area doesn't like huge counts. We limit
 190  * them to something that fits in "int" so that others
 191  * won't have to do range checks all the time.
 192  */
 193 #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
 194
 195 int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
 196 {
 197         struct inode *inode;
 198         loff_t pos;
 199
 200         inode = file->f_path.dentry->d_inode;
 201         if (unlikely((ssize_t) count < 0))
 202                 goto Einval;
 203         pos = *ppos;
 204         if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
 205                 goto Einval;
 206
 207         if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) {
 208                 int retval = locks_mandatory_area(
 209                         read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
 210                         inode, file, pos, count);
 211                 if (retval < 0)
 212                         return retval;
 213         }
 214         return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
 215
 216 Einval:
 217         return -EINVAL;
 218 }
 219
 220 static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
 221 {
 222         set_current_state(TASK_UNINTERRUPTIBLE);
 223         if (!kiocbIsKicked(iocb))
 224                 schedule();
 225         else
 226                 kiocbClearKicked(iocb);
 227         __set_current_state(TASK_RUNNING);
 228 }
 229
 230 ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
 231 {
 232         struct iovec iov = { .iov_base = buf, .iov_len = len };
 233         struct kiocb kiocb;
 234         ssize_t ret;
 235
 236         init_sync_kiocb(&kiocb, filp);
 237         kiocb.ki_pos = *ppos;
 238         kiocb.ki_left = len;
 239
 240         for (;;) {
 241                 ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
 242                 if (ret != -EIOCBRETRY)
 243                         break;
 244                 wait_on_retry_sync_kiocb(&kiocb);
 245         }
 246
 247         if (-EIOCBQUEUED == ret)
 248                 ret = wait_on_sync_kiocb(&kiocb);
 249         *ppos = kiocb.ki_pos;
 250         return ret;
 251 }
 252
 253 EXPORT_SYMBOL(do_sync_read);
 254
 255 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
 256 {
 257         ssize_t ret;
 258
 259         if (!(file->f_mode & FMODE_READ))
 260                 return -EBADF;
 261         if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
 262                 return -EINVAL;
 263         if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
 264                 return -EFAULT;
 265
 266         ret = rw_verify_area(READ, file, pos, count);
 267         if (ret >= 0) {
 268                 count = ret;
 269                 ret = security_file_permission (file, MAY_READ);
 270                 if (!ret) {
 271                         if (file->f_op->read)
 272                                 ret = file->f_op->read(file, buf, count, pos);
 273                         else
 274                                 ret = do_sync_read(file, buf, count, pos);
 275                         if (ret > 0) {
 276                                 fsnotify_access(file->f_path.dentry);
 277                                 add_rchar(current, ret);
 278                         }
 279                         inc_syscr(current);
 280                 }
 281         }
 282
 283         return ret;
 284 }
 285
 286 EXPORT_SYMBOL(vfs_read);
 287
 288 ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
 289 {
 290         struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
 291         struct kiocb kiocb;
 292         ssize_t ret;
 293
 294         init_sync_kiocb(&kiocb, filp);
 295         kiocb.ki_pos = *ppos;
 296         kiocb.ki_left = len;
 297
 298         for (;;) {
 299                 ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
 300                 if (ret != -EIOCBRETRY)
 301                         break;
 302                 wait_on_retry_sync_kiocb(&kiocb);
 303         }
 304
 305         if (-EIOCBQUEUED == ret)
 306                 ret = wait_on_sync_kiocb(&kiocb);
 307         *ppos = kiocb.ki_pos;
 308         return ret;
 309 }
 310
 311 EXPORT_SYMBOL(do_sync_write);
 312
 313 ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
 314 {
 315         ssize_t ret;
 316
 317         if (!(file->f_mode & FMODE_WRITE))
 318                 return -EBADF;
 319         if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
 320                 return -EINVAL;
 321         if (unlikely(!access_ok(VERIFY_READ, buf, count)))
 322                 return -EFAULT;
 323
 324         ret = rw_verify_area(WRITE, file, pos, count);
 325         if (ret >= 0) {
 326                 count = ret;
 327                 ret = security_file_permission (file, MAY_WRITE);
 328                 if (!ret) {
 329                         if (file->f_op->write)
 330                                 ret = file->f_op->write(file, buf, count, pos);
 331                         else
 332                                 ret = do_sync_write(file, buf, count, pos);
 333                         if (ret > 0) {
 334                                 fsnotify_modify(file->f_path.dentry);
 335                                 add_wchar(current, ret);
 336                         }
 337                         inc_syscw(current);
 338                 }
 339         }
 340
 341         return ret;
 342 }
 343
 344 EXPORT_SYMBOL(vfs_write);
 345
 346 static inline loff_t file_pos_read(struct file *file)
 347 {
 348         return file->f_pos;
 349 }
 350
 351 static inline void file_pos_write(struct file *file, loff_t pos)
 352 {
 353         file->f_pos = pos;
 354 }
 355
 356 asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
 357 {
 358         struct file *file;
 359         ssize_t ret = -EBADF;
 360         int fput_needed;
 361
 362         file = fget_light(fd, &fput_needed);
 363         if (file) {
 364                 loff_t pos = file_pos_read(file);
 365                 ret = vfs_read(file, buf, count, &pos);
 366                 file_pos_write(file, pos);
 367                 fput_light(file, fput_needed);
 368         }
 369
 370         return ret;
 371 }
 372 EXPORT_SYMBOL_GPL(sys_read);
 373
 374 asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
 375 {
 376         struct file *file;
 377         ssize_t ret = -EBADF;
 378         int fput_needed;
 379
 380         file = fget_light(fd, &fput_needed);
 381         if (file) {
 382                 loff_t pos = file_pos_read(file);
 383                 ret = vfs_write(file, buf, count, &pos);
 384                 file_pos_write(file, pos);
 385                 fput_light(file, fput_needed);
 386         }
 387
 388         return ret;
 389 }
 390
 391 asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
 392                              size_t count, loff_t pos)
 393 {
 394         struct file *file;
 395         ssize_t ret = -EBADF;
 396         int fput_needed;
 397
 398         if (pos < 0)
 399                 return -EINVAL;
 400
 401         file = fget_light(fd, &fput_needed);
 402         if (file) {
 403                 ret = -ESPIPE;
 404                 if (file->f_mode & FMODE_PREAD)
 405                         ret = vfs_read(file, buf, count, &pos);
 406                 fput_light(file, fput_needed);
 407         }
 408
 409         return ret;
 410 }
 411
 412 asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
 413                               size_t count, loff_t pos)
 414 {
 415         struct file *file;
 416         ssize_t ret = -EBADF;
 417         int fput_needed;
 418
 419         if (pos < 0)
 420                 return -EINVAL;
 421
 422         file = fget_light(fd, &fput_needed);
 423         if (file) {
 424                 ret = -ESPIPE;
 425                 if (file->f_mode & FMODE_PWRITE)
 426                         ret = vfs_write(file, buf, count, &pos);
 427                 fput_light(file, fput_needed);
 428         }
 429
 430         return ret;
 431 }
 432
 433 /*
 434  * Reduce an iovec's length in-place.  Return the resulting number of segments
 435  */
 436 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
 437 {
 438         unsigned long seg = 0;
 439         size_t len = 0;
 440
 441         while (seg < nr_segs) {
 442                 seg++;
 443                 if (len + iov->iov_len >= to) {
 444                         iov->iov_len = to - len;
 445                         break;
 446                 }
 447                 len += iov->iov_len;
 448                 iov++;
 449         }
 450         return seg;
 451 }
 452
 453 ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
 454                 unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
 455 {
 456         struct kiocb kiocb;
 457         ssize_t ret;
 458
 459         init_sync_kiocb(&kiocb, filp);
 460         kiocb.ki_pos = *ppos;
 461         kiocb.ki_left = len;
 462         kiocb.ki_nbytes = len;
 463
 464         for (;;) {
 465                 ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
 466                 if (ret != -EIOCBRETRY)
 467                         break;
 468                 wait_on_retry_sync_kiocb(&kiocb);
 469         }
 470
 471         if (ret == -EIOCBQUEUED)
 472                 ret = wait_on_sync_kiocb(&kiocb);
 473         *ppos = kiocb.ki_pos;
 474         return ret;
 475 }
 476
 477 /* Do it by hand, with file-ops */
 478 ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
 479                 unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
 480 {
 481         struct iovec *vector = iov;
 482         ssize_t ret = 0;
 483
 484         while (nr_segs > 0) {
 485                 void __user *base;
 486                 size_t len;
 487                 ssize_t nr;
 488
 489                 base = vector->iov_base;
 490                 len = vector->iov_len;
 491                 vector++;
 492                 nr_segs--;
 493
 494                 nr = fn(filp, base, len, ppos);
 495
 496                 if (nr < 0) {
 497                         if (!ret)
 498                                 ret = nr;
 499                         break;
 500                 }
 501                 ret += nr;
 502                 if (nr != len)
 503                         break;
 504         }
 505
 506         return ret;
 507 }
 508
 509 /* A write operation does a read from user space and vice versa */
 510 #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
 511
 512 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
 513                               unsigned long nr_segs, unsigned long fast_segs,
 514                               struct iovec *fast_pointer,
 515                               struct iovec **ret_pointer)
 516   {
 517         unsigned long seg;
 518         ssize_t ret;
 519         struct iovec *iov = fast_pointer;
 520
 521         /*
 522          * SuS says "The readv() function *may* fail if the iovcnt argument
 523          * was less than or equal to 0, or greater than {IOV_MAX}.  Linux has
 524          * traditionally returned zero for zero segments, so...
 525          */
 526         if (nr_segs == 0) {
 527                 ret = 0;
 528                 goto out;
 529         }
 530
 531         /*
 532          * First get the "struct iovec" from user memory and
 533          * verify all the pointers
 534          */
 535         if (nr_segs > UIO_MAXIOV) {
 536                 ret = -EINVAL;
 537                 goto out;
 538         }
 539         if (nr_segs > fast_segs) {
 540                 iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
 541                 if (iov == NULL) {
 542                         ret = -ENOMEM;
 543                         goto out;
 544                 }
 545         }
 546         if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
 547                 ret = -EFAULT;
 548                 goto out;
 549         }
 550
 551         /*
 552          * According to the Single Unix Specification we should return EINVAL
 553          * if an element length is < 0 when cast to ssize_t or if the
 554          * total length would overflow the ssize_t return value of the
 555          * system call.
 556          */
 557         ret = 0;
 558         for (seg = 0; seg < nr_segs; seg++) {
 559                 void __user *buf = iov[seg].iov_base;
 560                 ssize_t len = (ssize_t)iov[seg].iov_len;
 561
 562                 /* see if we we're about to use an invalid len or if
 563                  * it's about to overflow ssize_t */
 564                 if (len < 0 || (ret + len < ret)) {
 565                         ret = -EINVAL;
 566                         goto out;
 567                 }
 568                 if (unlikely(!access_ok(vrfy_dir(type), buf, len))) {
 569                         ret = -EFAULT;
 570                         goto out;
 571                 }
 572
 573                 ret += len;
 574         }
 575 out:
 576         *ret_pointer = iov;
 577         return ret;
 578 }
 579
 580 static ssize_t do_readv_writev(int type, struct file *file,
 581                                const struct iovec __user * uvector,
 582                                unsigned long nr_segs, loff_t *pos)
 583 {
 584         size_t tot_len;
 585         struct iovec iovstack[UIO_FASTIOV];
 586         struct iovec *iov = iovstack;
 587         ssize_t ret;
 588         io_fn_t fn;
 589         iov_fn_t fnv;
 590
 591         if (!file->f_op) {
 592                 ret = -EINVAL;
 593                 goto out;
 594         }
 595
 596         ret = rw_copy_check_uvector(type, uvector, nr_segs,
 597                         ARRAY_SIZE(iovstack), iovstack, &iov);
 598         if (ret <= 0)
 599                 goto out;
 600
 601         tot_len = ret;
 602         ret = rw_verify_area(type, file, pos, tot_len);
 603         if (ret < 0)
 604                 goto out;
 605         ret = security_file_permission(file, type == READ ? MAY_READ : MAY_WRITE);
 606         if (ret)
 607                 goto out;
 608
 609         fnv = NULL;
 610         if (type == READ) {
 611                 fn = file->f_op->read;
 612                 fnv = file->f_op->aio_read;
 613         } else {
 614                 fn = (io_fn_t)file->f_op->write;
 615                 fnv = file->f_op->aio_write;
 616         }
 617
 618         if (fnv)
 619                 ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
 620                                                 pos, fnv);
 621         else
 622                 ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
 623
 624 out:
 625         if (iov != iovstack)
 626                 kfree(iov);
 627         if ((ret + (type == READ)) > 0) {
 628                 if (type == READ)
 629                         fsnotify_access(file->f_path.dentry);
 630                 else
 631                         fsnotify_modify(file->f_path.dentry);
 632         }
 633         return ret;
 634 }
 635
 636 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
 637                   unsigned long vlen, loff_t *pos)
 638 {
 639         if (!(file->f_mode & FMODE_READ))
 640                 return -EBADF;
 641         if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
 642                 return -EINVAL;
 643
 644         return do_readv_writev(READ, file, vec, vlen, pos);
 645 }
 646
 647 EXPORT_SYMBOL(vfs_readv);
 648
 649 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
 650                    unsigned long vlen, loff_t *pos)
 651 {
 652         if (!(file->f_mode & FMODE_WRITE))
 653                 return -EBADF;
 654         if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
 655                 return -EINVAL;
 656
 657         return do_readv_writev(WRITE, file, vec, vlen, pos);
 658 }
 659
 660 EXPORT_SYMBOL(vfs_writev);
 661
 662 asmlinkage ssize_t
 663 sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
 664 {
 665         struct file *file;
 666         ssize_t ret = -EBADF;
 667         int fput_needed;
 668
 669         file = fget_light(fd, &fput_needed);
 670         if (file) {
 671                 loff_t pos = file_pos_read(file);
 672                 ret = vfs_readv(file, vec, vlen, &pos);
 673                 file_pos_write(file, pos);
 674                 fput_light(file, fput_needed);
 675         }
 676
 677         if (ret > 0)
 678                 add_rchar(current, ret);
 679         inc_syscr(current);
 680         return ret;
 681 }
 682
 683 asmlinkage ssize_t
 684 sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
 685 {
 686         struct file *file;
 687         ssize_t ret = -EBADF;
 688         int fput_needed;
 689
 690         file = fget_light(fd, &fput_needed);
 691         if (file) {
 692                 loff_t pos = file_pos_read(file);
 693                 ret = vfs_writev(file, vec, vlen, &pos);
 694                 file_pos_write(file, pos);
 695                 fput_light(file, fput_needed);
 696         }
 697
 698         if (ret > 0)
 699                 add_wchar(current, ret);
 700         inc_syscw(current);
 701         return ret;
 702 }
 703
 704 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 705                            size_t count, loff_t max)
 706 {
 707         struct file * in_file, * out_file;
 708         struct inode * in_inode, * out_inode;
 709         loff_t pos;
 710         ssize_t retval;
 711         int fput_needed_in, fput_needed_out;
 712
 713         /*
 714          * Get input file, and verify that it is ok..
 715          */
 716         retval = -EBADF;
 717         in_file = fget_light(in_fd, &fput_needed_in);
 718         if (!in_file)
 719                 goto out;
 720         if (!(in_file->f_mode & FMODE_READ))
 721                 goto fput_in;
 722         retval = -EINVAL;
 723         in_inode = in_file->f_path.dentry->d_inode;
 724         if (!in_inode)
 725                 goto fput_in;
 726         if (!in_file->f_op || !in_file->f_op->sendfile)
 727                 goto fput_in;
 728         retval = -ESPIPE;
 729         if (!ppos)
 730                 ppos = &in_file->f_pos;
 731         else
 732                 if (!(in_file->f_mode & FMODE_PREAD))
 733                         goto fput_in;
 734         retval = rw_verify_area(READ, in_file, ppos, count);
 735         if (retval < 0)
 736                 goto fput_in;
 737         count = retval;
 738
 739         retval = security_file_permission (in_file, MAY_READ);
 740         if (retval)
 741                 goto fput_in;
 742
 743         /*
 744          * Get output file, and verify that it is ok..
 745          */
 746         retval = -EBADF;
 747         out_file = fget_light(out_fd, &fput_needed_out);
 748         if (!out_file)
 749                 goto fput_in;
 750         if (!(out_file->f_mode & FMODE_WRITE))
 751                 goto fput_out;
 752         retval = -EINVAL;
 753         if (!out_file->f_op || !out_file->f_op->sendpage)
 754                 goto fput_out;
 755         out_inode = out_file->f_path.dentry->d_inode;
 756         retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
 757         if (retval < 0)
 758                 goto fput_out;
 759         count = retval;
 760
 761         retval = security_file_permission (out_file, MAY_WRITE);
 762         if (retval)
 763                 goto fput_out;
 764
 765         if (!max)
 766                 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
 767
 768         pos = *ppos;
 769         retval = -EINVAL;
 770         if (unlikely(pos < 0))
 771                 goto fput_out;
 772         if (unlikely(pos + count > max)) {
 773                 retval = -EOVERFLOW;
 774                 if (pos >= max)
 775                         goto fput_out;
 776                 count = max - pos;
 777         }
 778
 779         retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
 780
 781         if (retval > 0) {
 782                 add_rchar(current, retval);
 783                 add_wchar(current, retval);
 784         }
 785
 786         inc_syscr(current);
 787         inc_syscw(current);
 788         if (*ppos > max)
 789                 retval = -EOVERFLOW;
 790
 791 fput_out:
 792         fput_light(out_file, fput_needed_out);
 793 fput_in:
 794         fput_light(in_file, fput_needed_in);
 795 out:
 796         return retval;
 797 }
 798
 799 asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count)
 800 {
 801         loff_t pos;
 802         off_t off;
 803         ssize_t ret;
 804
 805         if (offset) {
 806                 if (unlikely(get_user(off, offset)))
 807                         return -EFAULT;
 808                 pos = off;
 809                 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
 810                 if (unlikely(put_user(pos, offset)))
 811                         return -EFAULT;
 812                 return ret;
 813         }
 814
 815         return do_sendfile(out_fd, in_fd, NULL, count, 0);
 816 }
 817
 818 asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count)
 819 {
 820         loff_t pos;
 821         ssize_t ret;
 822
 823         if (offset) {
 824                 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
 825                         return -EFAULT;
 826                 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
 827                 if (unlikely(put_user(pos, offset)))
 828                         return -EFAULT;
 829                 return ret;
 830         }
 831
 832         return do_sendfile(out_fd, in_fd, NULL, count, 0);
 833 }