mknod.2

早期freebsd实现

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.\"     @(#)mknod.2	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt MKNOD 2
.Os BSD 4
.Sh NAME
.Nm mknod
.Nd make a special file node
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft int
.Fn mknod "const char *path" "mode_t mode" "dev_t dev"
.Sh DESCRIPTION
The device special file
.Fa path
is created with the major and minor
device numbers extracted from
.Fa mode.
The access permissions of
.Fa path
are descendant from the
.Xr umask 2
of the parent process.
.Pp
If
.Fa mode
indicates a block or character special file,
.Fa dev
is a configuration dependent specification of a character or block
I/O device and the superblock of the device.  If
.Fa mode
does not indicate a block special or character special device,
.Fa dev
is ignored.
.Pp
.Fn Mknod
requires super-user privileges.
.Sh RETURN VALUES
Upon successful completion a value of 0 is returned.
Otherwise, a value of -1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn Mknod
will fail and the file will be not created if:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er EINVAL
The pathname contains a character with the high-order bit set.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 255 characters,
or an entire path name exceeded 1023 characters.
.It Bq Er ENOENT
A component of the path prefix does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EPERM
The process's effective user ID is not super-user.
.It Bq Er EPERM
The pathname contains a character with the high-order bit set.
.It Bq Er EIO
An I/O error occurred while making the directory entry or allocating the inode.
.It Bq Er 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 directory.
.It Bq Er ENOSPC
There are no free inodes on the file system on which the
node is being created.
.It Bq Er 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.
.It Bq Er EDQUOT
The user's quota of inodes on the file system on
which the node is being created has been exhausted.
.It Bq Er EROFS
The named file resides on a read-only file system.
.It Bq Er EEXIST
The named file exists.
.It Bq Er EFAULT
.Fa Path
points outside the process's allocated address space.
.El
.Sh SEE ALSO
.Xr chmod 2 ,
.Xr stat 2 ,
.Xr umask 2
.Sh HISTORY
A
.Nm
function call appeared in Version 6 AT&T UNIX.