1.\" $OpenBSD: mknod.2,v 1.14 2011/07/19 07:06:22 jmc Exp $ 2.\" $NetBSD: mknod.2,v 1.6 1995/02/27 12:34:33 cgd Exp $ 3.\" 4.\" Copyright (c) 1980, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)mknod.2 8.1 (Berkeley) 6/4/93 32.\" 33.Dd $Mdocdate: July 19 2011 $ 34.Dt MKNOD 2 35.Os 36.Sh NAME 37.Nm mknod , 38.Nm mknodat 39.Nd make a special file node 40.Sh SYNOPSIS 41.Fd #include <sys/stat.h> 42.Fd #include <fcntl.h> 43.Ft int 44.Fn mknod "const char *path" "mode_t mode" "dev_t dev" 45.Ft int 46.Fn mknodat "int fd" "const char *path" "mode_t mode" "dev_t dev" 47.Sh DESCRIPTION 48The device special file 49.Fa path 50is created with the major and minor 51device numbers extracted from 52.Fa mode . 53The access permissions of 54.Fa path 55are descendant from the 56.Xr umask 2 57of the parent process. 58.Pp 59If 60.Fa mode 61indicates a block or character special file, 62.Fa dev 63is a configuration dependent specification of a character or block 64I/O device and the superblock of the device. 65If 66.Fa mode 67does not indicate a block special or character special device, 68.Fa dev 69is ignored. 70.Pp 71.Fn mknod 72requires superuser privileges. 73.Pp 74The 75.Fn mknodat 76function is equivalent to 77.Fn mknod 78except that where 79.Fa path 80specifies a relative path, 81the newly created device special file is created relative to 82the directory associated with file descriptor 83.Fa fd 84instead of the current working directory. 85.Pp 86If 87.Fn mknodat 88is passed the special value 89.Dv AT_FDCWD 90(defined in 91.In fcntl.h ) 92in the 93.Fa fd 94parameter, the current working directory is used 95and the behavior is identical to a call to 96.Fn mknod . 97.Sh RETURN VALUES 98Upon successful completion a value of 0 is returned. 99Otherwise, a value of \-1 is returned and 100.Va errno 101is set to indicate the error. 102.Sh ERRORS 103.Fn mknod 104and 105.Fn mknodat 106will fail and the file will be not created if: 107.Bl -tag -width Er 108.It Bq Er ENOTDIR 109A component of the path prefix is not a directory. 110.It Bq Er ENAMETOOLONG 111A component of a pathname exceeded 112.Dv {NAME_MAX} 113characters, or an entire path name exceeded 114.Dv {PATH_MAX} 115characters. 116.It Bq Er ENOENT 117A component of the path prefix does not exist. 118.It Bq Er EACCES 119Search permission is denied for a component of the path prefix. 120.It Bq Er ELOOP 121Too many symbolic links were encountered in translating the pathname. 122.It Bq Er EPERM 123The process's effective user ID is not superuser. 124.It Bq Er EIO 125An I/O error occurred while making the directory entry or allocating the inode. 126.It Bq Er ENOSPC 127The directory in which the entry for the new node is being placed 128cannot be extended because there is no space left on the file 129system containing the directory. 130.It Bq Er ENOSPC 131There are no free inodes on the file system on which the 132node is being created. 133.It Bq Er EDQUOT 134The directory in which the entry for the new node 135is being placed cannot be extended because the 136user's quota of disk blocks on the file system 137containing the directory has been exhausted. 138.It Bq Er EDQUOT 139The user's quota of inodes on the file system on 140which the node is being created has been exhausted. 141.It Bq Er EROFS 142The named file resides on a read-only file system. 143.It Bq Er EEXIST 144The named file exists. 145.It Bq Er EFAULT 146.Fa path 147points outside the process's allocated address space. 148.It Bq Er EINVAL 149The process is running within an alternate root directory, as 150created by 151.Xr chroot 2 . 152.El 153Additionally, 154.Fn mknodat 155will fail if: 156.Bl -tag -width Er 157.It Bq Er EBADF 158The 159.Fa path 160argument does not specify an absolute path and the 161.Fa fd 162argument is neither 163.Dv AT_FDCWD 164nor a valid file descriptor open for reading. 165.El 166.Sh SEE ALSO 167.Xr chmod 2 , 168.Xr chroot 2 , 169.Xr stat 2 , 170.Xr umask 2 171.Sh HISTORY 172A 173.Fn mknod 174function call appeared in 175.At v6 . 176The 177.Fn mknodat 178function appeared in 179.Ox 5.0 . 180