GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
DECLARE_GEOM_CLASS(9) FreeBSD Kernel Developer's Manual DECLARE_GEOM_CLASS(9)

DECLARE_GEOM_CLASS
GEOM class declaration macro

#include <geom/geom.h>
DECLARE_GEOM_CLASS(class, mod_name);

The DECLARE_GEOM_CLASS() macro registers a GEOM class in GEOM. A GEOM class itself implements one particular kind of transformation. Typical examples are: MBR disk partition, BSD disklabel and RAID5 classes. DECLARE_GEOM_CLASS() can be used both for compiled in and loaded as kld(4) modules GEOM classes and it is the only official way for class registration.
The arguments to DECLARE_GEOM_CLASS() are:
class
The g_class structure which describes a GEOM class.
mod_name
A kernel module name (not a class name!).
Structure g_class contains data describing the class. They are:
const char * name
Class name.
g_taste_t * taste
Pointer to function used for taste event handling. If it is non-NULL it is called in three situations:
  • On class activation, all existing providers are offered for tasting.
  • When new provider is created it is offered for tasting.
  • After last write access to a provider is closed it is offered for retasting (on first write open event “spoil” was sent).
g_config_t * config
This field is not used anymore, its functionality was replaced by the ctlreq field.
g_ctl_req_t * ctlreq
Pointer to function used for handling events from userland applications.
g_init_t * init
Pointer to function which is called right after class registration.
g_fini_t * fini
Pointer to function which is called right before class deregistration.
g_ctl_destroy_geom_t * destroy_geom
Pointer to a function which is called for every geom on class unload. If this field is not set, the class can not be unloaded.
Only a name field is required; the rest are optional.

The fields of g_class should always be initialized using C99-style field naming (see the initialization of example_class below).

Example class declaration.
static struct g_geom * 
g_example_taste(struct g_class *mp, struct g_provider *pp, 
    int flags __unused) 
{ 
	g_topology_assert(); 
 
	[...] 
} 
 
static void 
g_example_ctlreq(struct gctl_req *req, struct g_class *cp, 
    char const *verb) 
{ 
 
	[...] 
} 
 
static int 
g_example_destroy_geom(struct gctl_req *req, struct g_class *cp, 
    struct g_geom *gp) 
{ 
 
	g_topology_assert(); 
 
	[...] 
} 
 
static void 
g_example_init(struct g_class *mp) 
{ 
 
	[...] 
} 
 
static void 
g_example_fini(struct g_class *mp) 
{ 
 
	[...] 
} 
 
struct g_class example_class = { 
	.name = "EXAMPLE", 
	.taste = g_example_taste, 
	.ctlreq = g_example_ctlreq, 
	.init = g_example_init, 
	.fini = g_example_fini, 
	.destroy_geom = g_example_destroy_geom 
}; 
 
DECLARE_GEOM_CLASS(example_class, g_example);

geom(4), g_attach(9), g_bio(9), g_consumer(9), g_data(9), g_event(9), g_geom(9), g_provider(9), g_provider_by_name(9), g_wither_geom(9)

This manual page was written by Pawel Jakub Dawidek <pjd@FreeBSD.org>.
August 13, 2007 FreeBSD 12.0-RELEASE

Search for    or go to Top of page |  Section 9 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.