1.\" 2.\" Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd January 16, 2004 28.Dt DECLARE_GEOM_CLASS 9 29.Os 30.Sh NAME 31.Nm DECLARE_GEOM_CLASS 32.Nd "GEOM class declaration macro" 33.Sh SYNOPSIS 34.In geom/geom.h 35.Fn DECLARE_GEOM_CLASS "class" "mod_name" 36.Sh DESCRIPTION 37The 38.Fn DECLARE_GEOM_CLASS 39macro registers a GEOM class in GEOM. 40A GEOM class itself implements one particular kind of transformation. 41Typical examples are: MBR disk partition, 42.Bx 43disklabel and RAID5 classes. 44.Fn DECLARE_GEOM_CLASS 45can be used both for compiled in and loaded as 46.Xr kld 4 47modules GEOM classes and it is the only official way for class registration. 48.Pp 49The arguments to 50.Fn DECLARE_GEOM_CLASS 51are: 52.Bl -inset -offset indent 53.It Fa class 54is the 55.Vt g_class 56structure which describes a GEOM class. 57.It Fa mod_name 58is a kernel module name (not a class name!). 59.El 60.Pp 61Structure 62.Vt g_class 63contains data describing the class. 64They are: 65.Bl -tag -offset indent -width indent 66.It Vt "const char *" Va name 67Class name. 68.It Vt "g_taste_t *" Va taste 69Pointer to function used for taste event handling. 70If it is 71.Pf non- Dv NULL 72it is called in three situations: 73.Pp 74.Bl -dash -compact 75.It 76On class activation, all existing providers are offered for tasting. 77.It 78When new provider is created it is offered for tasting. 79.It 80After last write access to a provider is closed it is offered for retasting 81(on first write open event 82.Dq spoil 83was sent). 84.El 85.It Vt "g_config_t *" Va config 86This field is not used anymore, its functionality was replaced by the 87.Va ctlreq 88field. 89.It Vt "g_ctl_req_t *" Va ctlreq 90Pointer to function used for handling events from userland applications. 91.It Vt "g_init_t *" Va init 92Pointer to function which is called right after class registration. 93.It Vt "g_fini_t *" Va fini 94Pointer to function which is called right before class deregistration. 95.It Vt "g_ctl_destroy_geom_t *" Va destroy_geom 96Pointer to a function which is called for every geom on class unload. 97If this field is not set, the class can not be unloaded. 98.El 99.Pp 100Only field 101.Fa name 102is required, the rest is optional. 103.Sh RESTRICTIONS/CONDITIONS 104In the 105.Vt g_class 106initialization one must use C99 initialization (just like in the example below). 107.Sh EXAMPLES 108Example class declaration. 109.Bd -literal -offset indent 110static struct geom * 111g_example_taste(struct g_class *mp, struct g_provider *pp, 112 int flags __unused) 113{ 114 g_topology_assert(); 115 116 [...] 117} 118 119static void 120g_example_ctlreq(struct gctl_req *req, struct g_class *cp, 121 char const *verb) 122{ 123 124 [...] 125} 126 127static int 128g_example_destroy_geom(struct gctl_req *req, struct g_class *cp, 129 struct g_geom *gp) 130{ 131 132 g_topology_assert(); 133 134 [...] 135} 136 137static void 138g_example_init(struct g_class *mp) 139{ 140 141 [...] 142} 143 144static void 145g_example_fini(struct g_class *mp) 146{ 147 148 [...] 149} 150 151struct g_class example_class = { 152 .name = "EXAMPLE", 153 .taste = g_example_taste, 154 .ctlreq = g_example_ctlreq, 155 .init = g_example_init, 156 .fini = g_example_fini, 157 .destroy_geom = g_example_destroy_geom 158}; 159 160DECLARE_GEOM_CLASS(example_class, g_example); 161.Ed 162.Sh SEE ALSO 163.Xr geom 4 , 164.Xr g_attach 9 , 165.Xr g_bio 9 , 166.Xr g_consumer 9 , 167.Xr g_data 9 , 168.Xr g_event 9 , 169.Xr g_geom 9 , 170.Xr g_provider 9 , 171.Xr g_provider_by_name 9 , 172.Xr g_wither_geom 9 173.Sh AUTHORS 174.An -nosplit 175This manual page was written by 176.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org . 177