1 .\" This manpage is Copyright (C) 1992 Drew Eckhardt;
2 .\" and Copyright (C) 1993 Michael Haardt
3 .\" and Copyright (C) 1993,1994 Ian Jackson
4 .\" and Copyright (C) 2006, 2014, Michael Kerrisk
6 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
7 .\" You may distribute it under the terms of the GNU General
8 .\" Public License. It comes with NO WARRANTY.
11 .\" Modified 1996-08-18 by urs
12 .\" Modified 2003-04-23 by Michael Kerrisk
13 .\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
15 .TH MKNOD 2 2014-02-21 "Linux" "Linux Programmer's Manual"
17 mknod, mknodat \- create a special or ordinary file
20 .B #include <sys/types.h>
21 .B #include <sys/stat.h>
23 .B #include <unistd.h>
25 .BI "int mknod(const char *" pathname ", mode_t " mode ", dev_t " dev );
27 .BR "#include <fcntl.h> " "/* Definition of AT_* constants */"
28 .B #include <sys/stat.h>
30 .BI "int mknodat(int " dirfd ", const char *" pathname ", mode_t " mode \
35 Feature Test Macro Requirements for glibc (see
36 .BR feature_test_macros (7)):
42 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
43 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
49 creates a filesystem node (file, device special file, or
52 with attributes specified by
59 argument specifies both the permissions to use and the type of node
61 It should be a combination (using bitwise OR) of one of the file types
62 listed below and the permissions for the new node.
64 The permissions are modified by the process's
66 in the usual way: the permissions of the created node are
67 .IR "(mode & ~umask)" .
69 The file type must be one of
76 .\" (S_IFSOCK since Linux 1.2.4)
77 to specify a regular file (which will be created empty), character
78 special file, block special file, FIFO (named pipe), or UNIX domain socket,
80 (Zero file type is equivalent to type
89 specifies the major and minor numbers of the newly created device
92 may be useful to build the value for
94 otherwise it is ignored.
98 already exists, or is a symbolic link, this call fails with an
102 The newly created node will be owned by the effective user ID of the
104 If the directory containing the node has the set-group-ID
105 bit set, or if the filesystem is mounted with BSD group semantics, the
106 new node will inherit the group ownership from its parent directory;
107 otherwise it will be owned by the effective group ID of the process.
113 system call operates in exactly the same way as
115 except for the differences described here.
117 If the pathname given in
119 is relative, then it is interpreted relative to the directory
120 referred to by the file descriptor
122 (rather than relative to the current working directory of
123 the calling process, as is done by
125 for a relative pathname).
135 is interpreted relative to the current working
136 directory of the calling process (like
147 for an explanation of the need for
153 return zero on success, or \-1 if an error occurred (in which case,
155 is set appropriately).
159 The parent directory does not allow write permission to the process,
160 or one of the directories in the path prefix of
162 did not allow search permission.
164 .BR path_resolution (7).)
167 The user's quota of disk blocks or inodes on the filesystem has been
173 This includes the case where
175 is a symbolic link, dangling or not.
178 .IR pathname " points outside your accessible address space."
182 requested creation of something other than a regular file, device
183 special file, FIFO or socket.
186 Too many symbolic links were encountered in resolving
190 .IR pathname " was too long."
193 A directory component in
195 does not exist or is a dangling symbolic link.
198 Insufficient kernel memory was available.
201 The device containing
203 has no room for the new node.
206 A component used as a directory in
208 is not, in fact, a directory.
212 requested creation of something other than a regular file,
213 FIFO (named pipe), or UNIX domain socket, and the caller
214 is not privileged (Linux: does not have the
217 .\" For UNIX domain sockets and regular files, EPERM is returned only in
218 .\" Linux 2.2 and earlier; in Linux 2.4 and later, unprivileged can
219 .\" use mknod() to make these files.
220 also returned if the filesystem containing
222 does not support the type of node requested.
226 refers to a file on a read-only filesystem.
228 The following additional errors can occur for
233 is not a valid file descriptor.
239 is a file descriptor referring to a file other than a directory.
242 was added to Linux in kernel 2.6.16;
243 library support was added to glibc in version 2.4.
246 SVr4, 4.4BSD, POSIX.1-2001 (but see below), POSIX.1-2008.
247 .\" The Linux version differs from the SVr4 version in that it
248 .\" does not require root permission to create pipes, also in that no
249 .\" EMULTIHOP, ENOLINK, or EINTR error is documented.
254 POSIX.1-2001 says: "The only portable use of
256 is to create a FIFO-special file.
263 is not 0, the behavior of
266 However, nowadays one should never use
268 for this purpose; one should use
270 a function especially defined for this purpose.
274 cannot be used to create directories.
275 One should make directories with
277 .\" and one should make UNIX domain sockets with socket(2) and bind(2).
279 There are many infelicities in the protocol underlying NFS.
296 .BR path_resolution (7)
298 This page is part of release 3.79 of the Linux
301 A description of the project,
302 information about reporting bugs,
303 and the latest version of this page,
305 \%http://www.kernel.org/doc/man\-pages/.