1 /*- 2 * Copyright (c) 2005 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 AUTHORS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/bio.h> 31 #include <sys/kernel.h> 32 #include <sys/limits.h> 33 #include <sys/malloc.h> 34 #include <sys/queue.h> 35 #include <sys/sysctl.h> 36 #include <sys/systm.h> 37 38 #include <geom/geom.h> 39 40 41 #define G_ZERO_CLASS_NAME "ZERO" 42 43 SYSCTL_DECL(_kern_geom); 44 SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW, 0, "GEOM_ZERO stuff"); 45 static int g_zero_clear = 1; 46 SYSCTL_INT(_kern_geom_zero, OID_AUTO, clear, CTLFLAG_RW, &g_zero_clear, 0, 47 "Clear read data buffer"); 48 static int g_zero_byte = 0; 49 SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0, 50 "Byte (octet) value to clear the buffers with"); 51 52 static void 53 g_zero_start(struct bio *bp) 54 { 55 int error = ENXIO; 56 57 switch (bp->bio_cmd) { 58 case BIO_READ: 59 if (g_zero_clear) 60 memset(bp->bio_data, g_zero_byte, bp->bio_length); 61 /* FALLTHROUGH */ 62 case BIO_DELETE: 63 case BIO_WRITE: 64 bp->bio_completed = bp->bio_length; 65 error = 0; 66 break; 67 case BIO_GETATTR: 68 default: 69 error = EOPNOTSUPP; 70 break; 71 } 72 g_io_deliver(bp, error); 73 } 74 75 static void 76 g_zero_init(struct g_class *mp) 77 { 78 struct g_geom *gp; 79 struct g_provider *pp; 80 81 g_topology_assert(); 82 gp = g_new_geomf(mp, "gzero"); 83 gp->start = g_zero_start; 84 gp->access = g_std_access; 85 pp = g_new_providerf(gp, "%s", gp->name); 86 pp->mediasize = 1152921504606846976LLU; 87 pp->sectorsize = 512; 88 g_error_provider(pp, 0); 89 } 90 91 static int 92 g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, 93 struct g_geom *gp) 94 { 95 struct g_provider *pp; 96 97 g_topology_assert(); 98 if (gp == NULL) 99 return (0); 100 pp = LIST_FIRST(&gp->provider); 101 if (pp == NULL) 102 return (0); 103 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) 104 return (EBUSY); 105 g_wither_geom(gp, ENXIO); 106 return (EBUSY); 107 } 108 109 static struct g_class g_zero_class = { 110 .name = G_ZERO_CLASS_NAME, 111 .version = G_VERSION, 112 .init = g_zero_init, 113 .destroy_geom = g_zero_destroy_geom 114 }; 115 116 DECLARE_GEOM_CLASS(g_zero_class, g_zero); 117