xref: /freebsd/share/man/man9/make_dev.9 (revision 77213b87eb43ce140e104a136c21fd62970da28b)
1.\" Copyright (c) 1999 Chris Costello
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25.\" $FreeBSD$
26.\"
27.Dd May 6, 2007
28.Os
29.Dt MAKE_DEV 9
30.Sh NAME
31.Nm make_dev ,
32.Nm make_dev_alias ,
33.Nm destroy_dev ,
34.Nm dev_depends
35.Nd manage
36.Vt cdev Ns 's
37and DEVFS registration for devices
38.Sh SYNOPSIS
39.In sys/param.h
40.In sys/conf.h
41.Ft struct cdev *
42.Fn make_dev "struct cdevsw *cdevsw" "int minor" "uid_t uid" "gid_t gid" "int perms" "const char *fmt" ...
43.Ft struct cdev *
44.Fn make_dev_alias "struct cdev *pdev" "const char *fmt" ...
45.Ft void
46.Fn destroy_dev "struct cdev *dev"
47.Ft void
48.Fn dev_depends "struct cdev *pdev" "struct cdev *cdev"
49.Sh DESCRIPTION
50The
51.Fn make_dev
52function creates a
53.Fa cdev
54structure for a new device.
55If DEVFS is available, it is also notified of
56the presence of the new device.
57The device will be owned by
58.Va uid ,
59with the group ownership as
60.Va gid .
61The name is the expansion of
62.Va fmt
63and following arguments as
64.Xr printf 9
65would print it.
66The name determines its path under
67.Pa /dev
68or other
69.Xr devfs 5
70mount point and may contain slash
71.Ql /
72characters to denote subdirectories.
73The permissions of the file specified in
74.Va perms
75are defined in
76.In sys/stat.h :
77.Pp
78.Bd -literal -offset indent -compact
79#define S_IRWXU 0000700    /* RWX mask for owner */
80#define S_IRUSR 0000400    /* R for owner */
81#define S_IWUSR 0000200    /* W for owner */
82#define S_IXUSR 0000100    /* X for owner */
83
84#define S_IRWXG 0000070    /* RWX mask for group */
85#define S_IRGRP 0000040    /* R for group */
86#define S_IWGRP 0000020    /* W for group */
87#define S_IXGRP 0000010    /* X for group */
88
89#define S_IRWXO 0000007    /* RWX mask for other */
90#define S_IROTH 0000004    /* R for other */
91#define S_IWOTH 0000002    /* W for other */
92#define S_IXOTH 0000001    /* X for other */
93
94#define S_ISUID 0004000    /* set user id on execution */
95#define S_ISGID 0002000    /* set group id on execution */
96#define S_ISVTX 0001000    /* sticky bit */
97#ifndef _POSIX_SOURCE
98#define S_ISTXT 0001000
99#endif
100.Ed
101.Pp
102The
103.Fn make_dev_alias
104function takes the returned
105.Ft cdev
106from
107.Fn make_dev
108and makes another (aliased) name for this device.
109It is an error to call
110.Fn make_dev_alias
111prior to calling
112.Fn make_dev .
113.Pp
114The
115.Fa cdev
116returned by
117.Fn make_dev
118and
119.Fn make_dev_alias
120has two fields,
121.Fa si_drv1
122and
123.Fa si_drv2 ,
124that are available to store state.
125Both fields are of type
126.Ft void * .
127These are designed to replace the
128.Fa minor
129argument to
130.Fn make_dev .
131.Pp
132The
133.Fn destroy_dev
134function takes the returned
135.Fa cdev
136from
137.Fn make_dev
138and destroys the registration for that device.
139Do not call
140.Fn destroy_dev
141on devices that were created with
142.Fn make_dev_alias .
143.Pp
144The
145.Fn dev_depends
146function establishes a parent-child relationship between two devices.
147The net effect is that a
148.Fn destroy_dev
149of the parent device will also result in the destruction of the
150child device(s),
151if any exist.
152A device may simultaneously be a parent and a child,
153so it is possible to build a complete hierarchy.
154.Sh SEE ALSO
155.Xr devfs 5
156.Sh HISTORY
157The
158.Fn make_dev
159and
160.Fn destroy_dev
161functions first appeared in
162.Fx 4.0 .
163The function
164.Fn make_dev_alias
165first appeared in
166.Fx 4.1 .
167The function
168.Fn dev_depends
169first appeared in
170.Fx 5.0 .
171