1 .\" This manpage is Copyright (C) 1992 Drew Eckhardt;
2 .\" 1993 Michael Haardt
3 .\" 1993,1994 Ian Jackson.
5 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
6 .\" You may distribute it under the terms of the GNU General
7 .\" Public License. It comes with NO WARRANTY.
10 .\" Modified 1996-08-18 by urs
11 .\" Modified 2003-04-23 by Michael Kerrisk
12 .\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
14 .TH MKNOD 2 2013-01-27 "Linux" "Linux Programmer's Manual"
16 mknod \- create a special or ordinary file
19 .B #include <sys/types.h>
20 .B #include <sys/stat.h>
22 .B #include <unistd.h>
24 .BI "int mknod(const char *" pathname ", mode_t " mode ", dev_t " dev );
28 Feature Test Macro Requirements for glibc (see
29 .BR feature_test_macros (7)):
35 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
36 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
42 creates a file system node (file, device special file or
45 with attributes specified by
52 argument specifies both the permissions to use and the type of node
54 It should be a combination (using bitwise OR) of one of the file types
55 listed below and the permissions for the new node.
57 The permissions are modified by the process's
59 in the usual way: the permissions of the created node are
60 .IR "(mode & ~umask)" .
62 The file type must be one of
69 .\" (S_IFSOCK since Linux 1.2.4)
70 to specify a regular file (which will be created empty), character
71 special file, block special file, FIFO (named pipe), or UNIX domain socket,
73 (Zero file type is equivalent to type
82 specifies the major and minor numbers of the newly created device
85 may be useful to build the value for
87 otherwise it is ignored.
91 already exists, or is a symbolic link, this call fails with an
95 The newly created node will be owned by the effective user ID of the
97 If the directory containing the node has the set-group-ID
98 bit set, or if the file system is mounted with BSD group semantics, the
99 new node will inherit the group ownership from its parent directory;
100 otherwise it will be owned by the effective group ID of the process.
103 returns zero on success, or \-1 if an error occurred (in which case,
105 is set appropriately).
109 The parent directory does not allow write permission to the process,
110 or one of the directories in the path prefix of
112 did not allow search permission.
114 .BR path_resolution (7).)
117 The user's quota of disk blocks or inodes on the file system has been
123 This includes the case where
125 is a symbolic link, dangling or not.
128 .IR pathname " points outside your accessible address space."
132 requested creation of something other than a regular file, device
133 special file, FIFO or socket.
136 Too many symbolic links were encountered in resolving
140 .IR pathname " was too long."
143 A directory component in
145 does not exist or is a dangling symbolic link.
148 Insufficient kernel memory was available.
151 The device containing
153 has no room for the new node.
156 A component used as a directory in
158 is not, in fact, a directory.
162 requested creation of something other than a regular file,
163 FIFO (named pipe), or UNIX domain socket, and the caller
164 is not privileged (Linux: does not have the
167 .\" For UNIX domain sockets and regular files, EPERM is only returned in
168 .\" Linux 2.2 and earlier; in Linux 2.4 and later, unprivileged can
169 .\" use mknod() to make these files.
170 also returned if the file system containing
172 does not support the type of node requested.
176 refers to a file on a read-only file system.
178 SVr4, 4.4BSD, POSIX.1-2001 (but see below).
179 .\" The Linux version differs from the SVr4 version in that it
180 .\" does not require root permission to create pipes, also in that no
181 .\" EMULTIHOP, ENOLINK, or EINTR error is documented.
183 POSIX.1-2001 says: "The only portable use of
185 is to create a FIFO-special file.
192 is not 0, the behavior of
195 However, nowadays one should never use
197 for this purpose; one should use
199 a function especially defined for this purpose.
201 Under Linux, this call cannot be used to create directories.
202 One should make directories with
204 .\" and one should make UNIX domain sockets with socket(2) and bind(2).
206 There are many infelicities in the protocol underlying NFS.
222 .BR path_resolution (7)