Fork us on GitHub Follow us on Facebook Follow us on Twitter

Changeset ed903174 in mainline for uspace/srv/bd/file_bd/file_bd.c


Ignore:
Timestamp:
2010-02-10T23:51:23Z (12 years ago)
Author:
Martin Decky <martin@…>
Branches:
lfn, master
Children:
e70edd1
Parents:
b32c604
Message:

implement support for 64bit file offsets

  • the libc API is a small deviation from standard, but we have no reason to keep a strict backward compatibility with ancient code so far
    • the basic signed 64bit offset type is called off64_t
      • lseek() and fseek() take off64_t arguments (since the argument represents a relative offset)
      • ftell() returns off64_t values (since it is a wrapper of lseek())
      • vfs_seek() implementation supports negative offsets when SEEK_CUR and SEEK_END is used
    • aoff64_t is used for internal unsigned representation of sizes (in bytes, blocks, etc.) and absolute offsets
      • mmap() and ftruncate() take aoff64_t arguments (since the full range of the absolute file offset should be used here)
      • struct stat stores the file size as aoff64_t
    • in both cases the explicit range of the types shown in the names is helpful for proper filesystem and IPC interaction
    • note: size_t should be used only for representing in-memory sizes and offsets, not device and file-related information, and vice versa
      • the code base still needs a thorough revision with respect to this rule
    • PRIdOFF64 and PRIuOFF64 can be used for printing the offsets
  • VFS_OUT_LOOKUP returns the 64bit file size in two IPC arguments
    • since all 5 IPC arguments have already been taken, the fs_handle is returned as the return value (fs_handle has only 16 bits, thus the return value can be used for both indicating errors as negative values and returning positive handles)
  • VFS_OUT_READ and VFS_OUT_WRITE use aoff64_t absolute offsets split into two IPC arguments

replace bn_t with aoff64_t as a generic 64bit bytes/block counter type

note: filesystem drivers need to be revised with respect to make sure that all out-of-range checks are correct (especially w.r.t. file and block offsets)

File:
1 edited

Legend:

Unmodified
Added
Removed
  • uspace/srv/bd/file_bd/file_bd.c

    rb32c604 red903174  
    5757
    5858static const size_t block_size = 512;
    59 static bn_t num_blocks;
     59static aoff64_t num_blocks;
    6060static FILE *img;
    6161
     
    210210        /* Check whether access is within device address bounds. */
    211211        if (ba + cnt > num_blocks) {
    212                 printf(NAME ": Accessed blocks %" PRIuBN "-%" PRIuBN ", while "
    213                     "max block number is %" PRIuBN ".\n", ba, ba + cnt - 1,
     212                printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
     213                    "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
    214214                    num_blocks - 1);
    215215                return ELIMIT;
     
    248248        /* Check whether access is within device address bounds. */
    249249        if (ba + cnt > num_blocks) {
    250                 printf(NAME ": Accessed blocks %" PRIuBN "-%" PRIuBN ", while "
    251                     "max block number is %" PRIuBN ".\n", ba, ba + cnt - 1,
     250                printf(NAME ": Accessed blocks %" PRIuOFF64 "-%" PRIuOFF64 ", while "
     251                    "max block number is %" PRIuOFF64 ".\n", ba, ba + cnt - 1,
    252252                    num_blocks - 1);
    253253                return ELIMIT;
Note: See TracChangeset for help on using the changeset viewer.