Defined Types


Defined In: kernel/fs_attr.h

typedef struct attr_info
   uint32 type;
   off_t size;
} attr_info;

The attr_info structure contains the following members



Is a constant (B_STRING_TYPE, B_INT32_TYPE, etc) that describes the type of data that the attribute holds.


Is the size of the attribute's data, in bytes.


Declared in: posix/sys/stat.h

The stat structure looks like this:

struct stat {
   dev_t         st_dev;
   ino_t         st_ino;
   mode_t        st_mode;
   nlink_t       st_nlink;
   uid_t         st_uid;
   gid_t         st_gid;
   off_t         st_size;
   dev_t         st_rdev;
   size_t        st_blksize;
   time_t        st_atime;
   time_t        st_mtime;
   time_t        st_ctime;
} stat;

And the fields are…



Identifies the node's device.


Is the node's "inode" number.

By combining st_dev and st_ino you can roll your own node_ref:

node_ref nref;
stat st;

if (file.GetStat(&st) == B_OK) { = st.st_dev;
   nref.node = st.st_ino;




Describes the node's flavor: plain file, directory or symbolic link. To test the field, pass it to the S_ISREG(), S_ISDIR(), and S_ISLNK() boolean macros:

if (S_ISREG(st.st_mode))
   /* it's a "regular" file */
   else if (S_ISDIR(st.st_mode))
      /* it's a directory */
      else if (S_ISLNK(st.st_mode))
         /* it's a symbolic link */


Is the number of "hard links" that point to this node.

st_uid and st_gid

Are the user (owner) and group ids that were described in the GetOwner() function.


Is, well, no one really knows. It's provided for System V compatibility (hold your applause), but it's unused.


Is the "preferred block size" that's used during copying. The cp command line program allocates buffers of this size when it's copying the file's data.

st_atime, st_mtime, and st_ctime

Are the access, modification, and creation times in seconds since January 1, 1970. Access time (st_atime) is currently unused.


The fs_info structure is defined as:

typedef struct fs_info {
    dev_t     dev;
    ino_t     root;
    uint32    flags;
    off_t     block_size;
    off_t     io_size;
    off_t     total_blocks;
    off_t     free_blocks;
    off_t     total_nodes;
    off_t     free_nodes;
    char      device_name[128];
    char      volume_name[B_FILE_NAME_LENGTH];
    char      fsh_name[B_OS_NAME_LENGTH];

The structure's fields are:

The flags can be any combination of the following values, which specify the attributes of the file system on the device:

The information in the fs_info structure is guaranteed to be internally consistent, but the structure as a whole should be considered to be out-of-date as soon as you receive it. It provides a picture of a device as it exists just before the info-retrieving function returns. In particular, the number of free blocks and of free nodes can easily change immediately after you receive this information.

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