c3954e3936
This is what SUSv4 requires, and also the only thing that works if strict standards compliance is requested or mknodat() is needed. PR: standards/123688 Submitted by: gcooper MFC after: 1 week
183 lines
5.1 KiB
Groff
183 lines
5.1 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)mknod.2 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd January 16, 2011
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.Dt MKNOD 2
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.Os
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.Sh NAME
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.Nm mknod ,
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.Nm mknodat
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.Nd make a special file node
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/stat.h
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.Ft int
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.Fn mknod "const char *path" "mode_t mode" "dev_t dev"
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.Ft int
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.Fn mknodat "int fd" "const char *path" "mode_t mode" "dev_t dev"
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.Sh DESCRIPTION
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The file system node
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.Fa path
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is created with the file type and access permissions specified in
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.Fa mode .
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The access permissions are modified by the process's umask value.
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.Pp
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If
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.Fa mode
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indicates a block or character special file,
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.Fa dev
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is a configuration dependent specification denoting a particular device
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on the system.
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Otherwise,
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.Fa dev
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is ignored.
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.Pp
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The
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.Fn mknod
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system call
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requires super-user privileges.
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.Pp
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The
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.Fn mknodat
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system call is equivalent to
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.Fn mknod
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except in the case where
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.Fa path
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specifies a relative path.
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In this case the newly created device node is created relative to the
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directory associated with the file descriptor
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.Fa fd
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instead of the current working directory.
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If
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.Fn mknodat
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is passed the special value
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.Dv AT_FDCWD
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in the
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.Fa fd
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parameter, the current working directory is used and the behavior is
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identical to a call to
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.Fn mknod .
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.Sh RETURN VALUES
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.Rv -std mknod
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.Sh ERRORS
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The
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.Fn mknod
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system call
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will fail and the file will be not created if:
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.Bl -tag -width Er
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.It Bq Er ENOTDIR
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A component of the path prefix is not a directory.
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.It Bq Er ENAMETOOLONG
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A component of a pathname exceeded 255 characters,
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or an entire path name exceeded 1023 characters.
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.It Bq Er ENOENT
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A component of the path prefix does not exist.
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.It Bq Er EACCES
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Search permission is denied for a component of the path prefix.
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.It Bq Er ELOOP
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Too many symbolic links were encountered in translating the pathname.
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.It Bq Er EPERM
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The process's effective user ID is not super-user.
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.It Bq Er EIO
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An I/O error occurred while making the directory entry or allocating the inode.
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.It Bq Er ENOSPC
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The directory in which the entry for the new node is being placed
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cannot be extended because there is no space left on the file
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system containing the directory.
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.It Bq Er ENOSPC
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There are no free inodes on the file system on which the
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node is being created.
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.It Bq Er EDQUOT
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The directory in which the entry for the new node
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is being placed cannot be extended because the
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user's quota of disk blocks on the file system
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containing the directory has been exhausted.
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.It Bq Er EDQUOT
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The user's quota of inodes on the file system on
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which the node is being created has been exhausted.
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.It Bq Er EROFS
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The named file resides on a read-only file system.
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.It Bq Er EEXIST
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The named file exists.
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.It Bq Er EFAULT
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The
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.Fa path
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argument
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points outside the process's allocated address space.
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.It Bq Er EINVAL
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Creating anything else than a block or character special
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file (or a
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.Em whiteout )
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is not supported.
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.El
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.Pp
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In addition to the errors returned by the
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.Fn mknod ,
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the
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.Fn mknodat
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may fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa path
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argument does not specify an absolute path and the
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.Fa fd
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argument is neither
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.Dv AT_FDCWD
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nor a valid file descriptor open for searching.
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.It Bq Er ENOTDIR
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The
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.Fa path
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argument is not an absolute path and
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.Fa fd
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is neither
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.Dv AT_FDCWD
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nor a file descriptor associated with a directory.
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.El
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.Sh SEE ALSO
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.Xr chmod 2 ,
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.Xr mkfifo 2 ,
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.Xr stat 2 ,
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.Xr umask 2
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.Sh STANDARDS
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The
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.Fn mknodat
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system call follows The Open Group Extended API Set 2 specification.
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.Sh HISTORY
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The
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.Fn mknod
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function appeared in
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.At v6 .
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The
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.Fn mknodat
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system call appeared in
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.Fx 8.0 .
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