1 .\" Copyright (c) 1999 Chris Costello
2 .\" All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
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18 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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25 .\" $FreeBSD: src/share/man/man9/make_dev.9,v 1.2.2.3 2001/12/17 11:30:18 ru Exp $
27 .Dd September 11, 2009
32 .Nm destroy_only_dev ,
33 .Nm devfs_scan_callback ,
34 .Nm dev_ops_intercept ,
35 .Nm dev_ops_remove_all ,
36 .Nm dev_ops_remove_minor ,
43 .Nd "device entry manipulation functions"
49 .Fn destroy_dev "cdev_t dev"
51 .Fn destroy_only_dev "cdev_t dev"
53 .Fn devfs_scan_callback "devfs_scan_t *callback"
55 .Fn dev_ops_intercept "cdev_t dev" "struct dev_ops *iops"
57 .Fn dev_ops_remove_all "struct dev_ops *ops"
59 .Fn dev_ops_restore "cdev_t dev" "struct dev_ops *oops"
61 .Fn dev_ops_remove_minor "struct dev_ops *ops" "int minor"
63 .Fn make_dev "struct dev_ops *ops" "int minor" "uid_t uid" "gid_t gid" "int perms" "char *fmt" ...
65 .Fn make_dev_alias "cdev_t target" "const char *fmt" ...
67 .Fn make_dev_covering "struct dev_ops *ops" "cdev_t rdev" "int minor" "uid_t uid" "gid_t gid" "int perms" "char *fmt" ...
69 .Fn make_only_dev "struct dev_ops *ops" "int minor" "uid_t uid" "gid_t gid" "int perms" "const char *fmt" ...
71 .Fn reference_dev "cdev_t dev"
73 .Fn release_dev "cdev_t dev"
79 structure for a new device and makes the device name visible in the
82 The device's name must be unique.
83 The name is the expansion of
85 and following arguments as
88 The name determines its path under
90 The permissions of the file specified in
95 .Bd -literal -offset indent -compact
96 #define S_IRWXU 0000700 /* RWX mask for owner */
97 #define S_IRUSR 0000400 /* R for owner */
98 #define S_IWUSR 0000200 /* W for owner */
99 #define S_IXUSR 0000100 /* X for owner */
101 #define S_IRWXG 0000070 /* RWX mask for group */
102 #define S_IRGRP 0000040 /* R for group */
103 #define S_IWGRP 0000020 /* W for group */
104 #define S_IXGRP 0000010 /* X for group */
106 #define S_IRWXO 0000007 /* RWX mask for other */
107 #define S_IROTH 0000004 /* R for other */
108 #define S_IWOTH 0000002 /* W for other */
109 #define S_IXOTH 0000001 /* X for other */
111 #define S_ISUID 0004000 /* set user id on execution */
112 #define S_ISGID 0002000 /* set group id on execution */
113 #define S_ISVTX 0001000 /* sticky bit */
114 #ifndef _POSIX_SOURCE
115 #define S_ISTXT 0001000
121 argument is a pointer to a
123 data structure, which is defined as follows:
127 const char *name; /* base name, e.g. 'da' */
128 int maj; /* major device number */
129 u_int flags; /* D_XXX flags */
130 void *data; /* custom driver data */
131 int refs; /* ref count */
135 #define dev_ops_first_field d_default
136 d_default_t *d_default;
143 d_strategy_t *d_strategy;
146 d_kqfilter_t *d_kqfilter;
147 d_clone_t *d_clone; /* clone from base dev_ops */
148 d_revoke_t *d_revoke;
149 #define dev_ops_last_field d_revoke
153 While one can and should initialize the
157 fields, they are effectively ignored.
158 Device major numbers are assigned automatically out of an internal pool of
159 major numbers, so there is no need to specify a unique major number in the
165 family is defined as:
167 typedef int d_xxx_t (struct dev_xxx_args *ap);
170 Therefore, if one wants to implement a
172 function, this is the way:
177 mydev_open(struct dev_open_args *ap)
182 .Fn make_dev_covering
183 is equivalent to make_dev, except that it also takes an argument
185 which is set as the backing device for the newly created device.
186 This function should be used whenever a device is created covering
187 another raw device, as the disk subsystem does.
192 structure and initializes it the same way
194 would, but the device will not appear in the
203 and destroys the registration for that device.
204 It should not be used to destroy a
214 and destroys the registration for that device.
215 It should not be used to destroy a
223 link (alias) with the given name to the
229 must have been created either by
231 or bt a clone handler.
232 Aliases are alternative names for devices in the
235 The lifetime of an alias is that of its associated
239 is removed or destroyed, the alias is also destroyed and its name is
247 Callers generally add their own references when they are going to store a device
248 node in a variable for long periods of time, to prevent a disassociation from
252 releases a reference on
254 The device will be terminated when the last reference has been released.
256 .Fn dev_ops_intercept
257 intercepts the device operations vector of
263 is returned which may be used in a subsequent
266 The function sets the
272 restores the device operations vector of
281 .Fn dev_ops_remove_all
286 and removes the devices from the
289 This function is useful when uninitializing a driver.
291 .Fn dev_ops_remove_minor
298 and removes the devices from the
302 .Fn devfs_scan_callback
305 function for every device registered in
309 function has the following form:
311 devfs_scan_t mydev_scan_callback;
314 mydev_scan_callback(cdev_t dev)
323 functions first appeared in
326 A major overhaul of these functions occurred in