Add some more *at() system calls.
[dragonfly.git] / lib / libc / sys / mknod.2
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28.\" @(#)mknod.2 8.1 (Berkeley) 6/4/93
6d98f93c 29.\" $FreeBSD: src/lib/libc/sys/mknod.2,v 1.18 2008/04/16 13:03:12 kib Exp $
984263bc 30.\"
6d98f93c 31.Dd August 6, 2010
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32.Dt MKNOD 2
33.Os
34.Sh NAME
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35.Nm mknod ,
36.Nm mknodat
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37.Nd make a special file node
38.Sh LIBRARY
39.Lb libc
40.Sh SYNOPSIS
46b457c2 41.In sys/stat.h
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42.Ft int
43.Fn mknod "const char *path" "mode_t mode" "dev_t dev"
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44.Ft int
45.Fn mknodat "int fd" "const char *path" "mode_t mode" "dev_t dev"
984263bc 46.Sh DESCRIPTION
6d98f93c 47The file system node
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48.Fa path
49is created with the file type and access permissions specified in
50.Fa mode .
51The access permissions are modified by the process's umask value.
52.Pp
53If
54.Fa mode
55indicates a block or character special file,
56.Fa dev
57is a configuration dependent specification denoting a particular device
58on the system.
59Otherwise,
60.Fa dev
61is ignored.
62.Pp
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63The
64.Fn mknod
65system call
984263bc 66requires super-user privileges.
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67.Pp
68The
69.Fn mknodat
70system call is equivalent to
71.Fn mknod
72except in the case where
73.Fa path
74specifies a relative path.
75In this case the newly created device node is created relative to the
76directory associated with the file descriptor
77.Fa fd
78instead of the current working directory.
79If
80.Fn mknodat
81is passed the special value
82.Dv AT_FDCWD
83in the
84.Fa fd
85parameter, the current working directory is used and the behavior is
86identical to a call to
87.Fn mknod .
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88.Sh RETURN VALUES
89.Rv -std mknod
90.Sh ERRORS
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91The
92.Fn mknod
93system call
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94will fail and the file will be not created if:
95.Bl -tag -width Er
96.It Bq Er ENOTDIR
97A component of the path prefix is not a directory.
98.It Bq Er ENAMETOOLONG
99A component of a pathname exceeded 255 characters,
100or an entire path name exceeded 1023 characters.
101.It Bq Er ENOENT
102A component of the path prefix does not exist.
103.It Bq Er EACCES
104Search permission is denied for a component of the path prefix.
105.It Bq Er ELOOP
106Too many symbolic links were encountered in translating the pathname.
107.It Bq Er EPERM
108The process's effective user ID is not super-user.
109.It Bq Er EIO
110An I/O error occurred while making the directory entry or allocating the inode.
111.It Bq Er ENOSPC
112The directory in which the entry for the new node is being placed
113cannot be extended because there is no space left on the file
114system containing the directory.
115.It Bq Er ENOSPC
116There are no free inodes on the file system on which the
117node is being created.
118.It Bq Er EDQUOT
119The directory in which the entry for the new node
120is being placed cannot be extended because the
121user's quota of disk blocks on the file system
122containing the directory has been exhausted.
123.It Bq Er EDQUOT
124The user's quota of inodes on the file system on
125which the node is being created has been exhausted.
126.It Bq Er EROFS
127The named file resides on a read-only file system.
128.It Bq Er EEXIST
129The named file exists.
130.It Bq Er EFAULT
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131The
132.Fa path
133argument
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134points outside the process's allocated address space.
135.It Bq Er EINVAL
136Creating anything else than a block or character special
137file (or a
138.Em whiteout )
139is not supported.
140.El
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141.Pp
142In addition to the errors returned by the
143.Fn mknod ,
144the
145.Fn mknodat
146may fail if:
147.Bl -tag -width Er
148.It Bq Er EBADF
149The
150.Fa path
151argument does not specify an absolute path and the
152.Fa fd
153argument is neither
154.Dv AT_FDCWD
155nor a valid file descriptor open for searching.
156.It Bq Er ENOTDIR
157The
158.Fa path
159argument is not an absolute path and
160.Fa fd
161is neither
162.Dv AT_FDCWD
163nor a file descriptor associated with a directory.
164.El
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165.Sh SEE ALSO
166.Xr chmod 2 ,
167.Xr mkfifo 2 ,
168.Xr stat 2 ,
169.Xr umask 2
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170.Sh STANDARDS
171The
172.Fn mknodat
173system call follows The Open Group Extended API Set 2 specification.
984263bc 174.Sh HISTORY
6d98f93c 175The
984263bc 176.Fn mknod
6d98f93c 177function appeared in
984263bc 178.At v6 .
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179The
180.Fn mknodat
181system call appeared in
182.Dx 2.7 .