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mknod

make block or character special files


  1. mknod.1.man
  2. mknod.2.man


1. mknod.1.man

Manpage of MKNOD

MKNOD

Section: User Commands (1)
Updated: October 2011
Index Return to Main Contents
 

NAME

mknod - make block or character special files  

SYNOPSIS

mknod [OPTION]... NAME TYPE [MAJOR MINOR]  

DESCRIPTION

Create the special file NAME of the given TYPE.

Mandatory arguments to long options are mandatory for short options too.

-m, --mode=MODE
set file permission bits to MODE, not a=rw - umask
-Z, --context=CTX
set the SELinux security context of NAME to CTX
--help
display this help and exit
--version
output version information and exit

Both MAJOR and MINOR must be specified when TYPE is b, c, or u, and they must be omitted when TYPE is p. If MAJOR or MINOR begins with 0x or 0X, it is interpreted as hexadecimal; otherwise, if it begins with 0, as octal; otherwise, as decimal. TYPE may be:

b
create a block (buffered) special file
c, u
create a character (unbuffered) special file
p
create a FIFO

NOTE: your shell may have its own version of mknod, which usually supersedes the version described here. Please refer to your shell's documentation for details about the options it supports.  

AUTHOR

Written by David MacKenzie.  

REPORTING BUGS

Report mknod bugs to bug-coreutils@gnu.org
GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
General help using GNU software: <http://www.gnu.org/gethelp/>
Report mknod translation bugs to <http://translationproject.org/team/>  

COPYRIGHT

Copyright © 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.  

SEE ALSO

mknod(2)

The full documentation for mknod is maintained as a Texinfo manual. If the info and mknod programs are properly installed at your site, the command

info coreutils aqmknod invocationaq

should give you access to the complete manual.


 

Index

NAME
SYNOPSIS
DESCRIPTION
AUTHOR
REPORTING BUGS
COPYRIGHT
SEE ALSO

This document was created by man2html using the manual pages.
Time: 17:31:44 GMT, October 23, 2013

2. mknod.2.man

Manpage of MKNOD

MKNOD

Section: Linux Programmer's Manual (2)
Updated: 2010-09-20
Index Return to Main Contents
 

NAME

mknod - create a special or ordinary file  

SYNOPSIS

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

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

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

mknod():

_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
 

DESCRIPTION

The system call mknod() creates a file system node (file, device special file or named pipe) named pathname, with attributes specified by mode and dev.

The mode argument specifies both the permissions to use and the type of node to be created. It should be a combination (using bitwise OR) of one of the file types listed below and the permissions for the new node.

The permissions are modified by the process's umask in the usual way: the permissions of the created node are (mode & ~umask).

The file type must be one of S_IFREG, S_IFCHR, S_IFBLK, S_IFIFO or S_IFSOCK to specify a regular file (which will be created empty), character special file, block special file, FIFO (named pipe), or UNIX domain socket, respectively. (Zero file type is equivalent to type S_IFREG.)

If the file type is S_IFCHR or S_IFBLK then dev specifies the major and minor numbers of the newly created device special file (makedev(3) may be useful to build the value for dev); otherwise it is ignored.

If pathname already exists, or is a symbolic link, this call fails with an EEXIST error.

The newly created node will be owned by the effective user ID of the process. If the directory containing the node has the set-group-ID bit set, or if the file system is mounted with BSD group semantics, the new node will inherit the group ownership from its parent directory; otherwise it will be owned by the effective group ID of the process.  

RETURN VALUE

mknod() returns zero on success, or -1 if an error occurred (in which case, errno is set appropriately).  

ERRORS

EACCES
The parent directory does not allow write permission to the process, or one of the directories in the path prefix of pathname did not allow search permission. (See also path_resolution(7).)
EEXIST
pathname already exists. This includes the case where pathname is a symbolic link, dangling or not.
EFAULT
pathname points outside your accessible address space.
EINVAL
mode requested creation of something other than a regular file, device special file, FIFO or socket.
ELOOP
Too many symbolic links were encountered in resolving pathname.
ENAMETOOLONG
pathname was too long.
ENOENT
A directory component in pathname does not exist or is a dangling symbolic link.
ENOMEM
Insufficient kernel memory was available.
ENOSPC
The device containing pathname has no room for the new node.
ENOTDIR
A component used as a directory in pathname is not, in fact, a directory.
EPERM
mode requested creation of something other than a regular file, FIFO (named pipe), or UNIX domain socket, and the caller is not privileged (Linux: does not have the CAP_MKNOD capability); also returned if the file system containing pathname does not support the type of node requested.
EROFS
pathname refers to a file on a read-only file system.
 

CONFORMING TO

SVr4, 4.4BSD, POSIX.1-2001 (but see below).  

NOTES

POSIX.1-2001 says: "The only portable use of mknod() is to create a FIFO-special file. If mode is not S_IFIFO or dev is not 0, the behavior of mknod() is unspecified." However, nowadays one should never use mknod() for this purpose; one should use mkfifo(3), a function especially defined for this purpose.

Under Linux, this call cannot be used to create directories. One should make directories with mkdir(2).

There are many infelicities in the protocol underlying NFS. Some of these affect mknod().  

SEE ALSO

chmod(2), chown(2), fcntl(2), mkdir(2), mknodat(2), mount(2), socket(2), stat(2), umask(2), unlink(2), makedev(3), mkfifo(3), path_resolution(7)  

COLOPHON

This page is part of release 3.32 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
NOTES
SEE ALSO
COLOPHON

This document was created by man2html using the manual pages.
Time: 17:31:44 GMT, October 23, 2013

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