3.3.11 Procedure 11: MKNOD - Create a special device

SYNOPSIS

      MKNOD3res NFSPROC3_MKNOD(MKNOD3args) = 11;

      struct devicedata3 {
           sattr3     dev_attributes;
           specdata3  spec;
      };

      union mknoddata3 switch (ftype3 type) {
      case NF3CHR:
      case NF3BLK:
           devicedata3  device;
      case NF3SOCK:
      case NF3FIFO:
           sattr3       pipe_attributes;
      default:
           void;
      };

      struct MKNOD3args {
           diropargs3   where;
           mknoddata3   what;
      };

      struct MKNOD3resok {
           post_op_fh3   obj;
           post_op_attr  obj_attributes;
           wcc_data      dir_wcc;
      };

      struct MKNOD3resfail {
           wcc_data      dir_wcc;
      };

      union MKNOD3res switch (nfsstat3 status) {
      case NFS3_OK:
           MKNOD3resok   resok;
      default:
           MKNOD3resfail resfail;
      };

DESCRIPTION

Procedure MKNOD creates a new special file of the type, what.type. Special files can be device files or named pipes. On entry, the arguments in MKNOD3args are:

where

The location of the special file to be created:

dir

The file handle for the directory in which the special file is to be created.

name

The name that is to be associated with the created special file. Refer to General comments on filenames on page 30.

what

A discriminated union identifying the type of the special file to be created along with the data and attributes appropriate to the type of the special file:

type

The type of the object to be created.

When creating a character special file (what.type is NF3CHR) or a block special file (what.type is NF3BLK), what includes:

device

A structure devicedata3 with the following components:

dev_attributes

The initial attributes for the special file.

spec

The major number stored in device.spec.specdata1 and the minor number stored in device.spec.specdata2.

When creating a socket (what.type is NF3SOCK) or a FIFO (what.type is NF3FIFO), what includes:

pipe_attributes

The initial attributes for the special file.

On successful return, MKNOD3res.status is NFS3_OK and MKNOD3res.resok contains:

obj

The file handle for the newly created special file.

obj_attributes

The attributes for the newly created special file.

dir_wcc

Weak cache consistency data for the directory, where.dir. For a client that requires only the post-MKNOD directory attributes, these can be found in dir_wcc.after.

Otherwise, MKNOD3res.status contains the error on failure and MKNOD3res.resfail contains the following:

dir_wcc

Weak cache consistency data for the directory, where.dir. For a client that requires only the post-MKNOD directory attributes, these can be found in dir_wcc.after. Even though the MKNOD failed, full wcc_data is returned to allow the client to determine whether the failing MKNOD changed the directory.

IMPLEMENTATION

Refer to General comments on filenames on page 30.

Without explicit support for special file type creation in the NFS version 2 protocol, fields in the CREATE arguments were overloaded to indicate creation of certain types of objects. This overloading is not necessary in the NFS version 3 protocol.

If the server does not support any of the defined types, the error, NFS3ERR_NOTSUPP, should be returned. Otherwise, if the server does not support the target type or the target type is illegal, the error, NFS3ERR_BADTYPE, should be returned. Note that NF3REG, NF3DIR, and NF3LNK are illegal types for MKNOD. The procedures, CREATE, MKDIR, and SYMLINK should be used to create these file types, respectively, instead of MKNOD.

ERRORS

NFS3ERR_IO NFS3ERR_ACCES NFS3ERR_EXIST NFS3ERR_NOTDIR NFS3ERR_NOSPC NFS3ERR_ROFS NFS3ERR_NAMETOOLONG NFS3ERR_DQUOT NFS3ERR_STALE NFS3ERR_BADHANDLE NFS3ERR_NOTSUPP NFS3ERR_SERVERFAULT NFS3ERR_BADTYPE

SEE ALSO CREATE, MKDIR, SYMLINK, and PATHCONF.