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

Changeset ed903174 in mainline for uspace/srv/fs/tmpfs/tmpfs_dump.c

2010-02-10T23:51:23Z (12 years ago)
Martin Decky <martin@…>
lfn, master

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)

1 edited


  • uspace/srv/fs/tmpfs/tmpfs_dump.c

    rb32c604 red903174  
    5656static bool
    57 tmpfs_restore_recursion(dev_handle_t dev, off_t *bufpos, size_t *buflen,
    58     off_t *pos, fs_node_t *pfn)
     57tmpfs_restore_recursion(dev_handle_t dev, size_t *bufpos, size_t *buflen,
     58    aoff64_t *pos, fs_node_t *pfn)
    6060        struct rdentry entry;
    171171                return false;
    173         off_t bufpos = 0;
     173        size_t bufpos = 0;
    174174        size_t buflen = 0;
    175         off_t pos = 0;
     175        aoff64_t pos = 0;
    177177        char tag[6];
Note: See TracChangeset for help on using the changeset viewer.