unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (OpenBSD-5.7)
Page:
Section:
Apropos / Subsearch:
optional field

MKNOD(2)                    BSD System Calls Manual                   MKNOD(2)

NAME
     mknod, mknodat -- make a special file node

SYNOPSIS
     #include <&lt;sys/stat.h>&gt;

     int
     mknod(const char *path, mode_t mode, dev_t dev);

     #include <&lt;sys/stat.h>&gt;
     #include <&lt;fcntl.h>&gt;

     int
     mknodat(int fd, const char *path, mode_t mode, dev_t dev);

DESCRIPTION
     The mknod() function creates path with a file type and mode of mode, as
     modified by umask(2).  Only FIFO and device special files are supported
     by this implementation.

     If mode is the bitwise OR of S_IFIFO and zero or more file permissions,
     and dev is zero, then a FIFO is created.  If mode is the bitwise OR of
     S_IFCHR or S_IFBLK and zero or more file permissions, then a character or
     block device special (respectively) is created with major and minor
     device numbers extracted from dev.

     The mknodat() function is equivalent to mknod() except that where path
     specifies a relative path, the newly created device special file is cre-
     ated relative to the directory associated with file descriptor fd instead
     of the current working directory.

     If mknodat() is passed the special value AT_FDCWD (defined in <fcntl.h>)
     in the fd parameter, the current working directory is used and the behav-
     ior is identical to a call to mknod().

     Creating a device special file with mknod() or mknodat() requires supe-
     ruser privileges.

RETURN VALUES
     Upon successful completion, the value 0 is returned; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS
     mknod() and mknodat() will fail and the file will be not created if:

     [EINVAL]           mode is an invalid file type or dev is an invalid
                        value for that file type.

     [ENOTDIR]          A component of the path prefix is not a directory.

     [ENAMETOOLONG]     A component of a pathname exceeded NAME_MAX charac-
                        ters, or an entire pathname (including the terminating
                        NUL) exceeded PATH_MAX bytes.

     [ENOENT]           A component of the path prefix does not exist.

     [EACCES]           Search permission is denied for a component of the
                        path prefix.

     [ELOOP]            Too many symbolic links were encountered in translat-
                        ing the pathname.

     [EPERM]            mode is a device special and the process's effective
                        user ID is not superuser.

     [EIO]              An I/O error occurred while making the directory entry
                        or allocating the inode.

     [ENOSPC]           The directory in which the entry for the new node is
                        being placed cannot be extended because there is no
                        space left on the file system containing the direc-
                        tory.

     [ENOSPC]           There are no free inodes on the file system on which
                        the node is being created.

     [EDQUOT]           The directory in which the entry for the new node is
                        being placed cannot be extended because the user's
                        quota of disk blocks on the file system containing the
                        directory has been exhausted.

     [EDQUOT]           The user's quota of inodes on the file system on which
                        the node is being created has been exhausted.

     [EROFS]            The named file resides on a read-only file system.

     [EEXIST]           The named file exists.

     [EFAULT]           path points outside the process's allocated address
                        space.

     [EINVAL]           The process is running within an alternate root direc-
                        tory, as created by chroot(2).

     Additionally, mknodat() will fail if:

     [EBADF]            The path argument specifies a relative path and the fd
                        argument is neither AT_FDCWD nor a valid file descrip-
                        tor.

     [ENOTDIR]          The path argument specifies a relative path and the fd
                        argument is a valid file descriptor but it does not
                        reference a directory.

     [EACCES]           The path argument specifies a relative path but search
                        permission is denied for the directory which the fd
                        file descriptor references.

SEE ALSO
     chmod(2), chroot(2), mkfifo(2), stat(2), umask(2)

STANDARDS
     The mknod() and mknodat() functions conform to IEEE Std 1003.1-2008
     (``POSIX.1'').

HISTORY
     The mknod() system call first appeared in Version 4 AT&T UNIX, and
     mknodat() has been available since OpenBSD 5.0.

BSD                            January 19, 2015                            BSD