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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/bio.h> 32 #include <sys/kernel.h> 33 #include <sys/limits.h> 34 #include <sys/malloc.h> 35 #include <sys/queue.h> 36 #include <sys/sysctl.h> 37 #include <sys/systm.h> 38 39 #include <geom/geom.h> 40 41 42 #define G_ZERO_CLASS_NAME "ZERO" 43 44 SYSCTL_DECL(_kern_geom); 45 SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW, 0, "GEOM_ZERO stuff"); 46 static int g_zero_clear = 1; 47 SYSCTL_INT(_kern_geom_zero, OID_AUTO, clear, CTLFLAG_RW, &g_zero_clear, 0, 48 "Clear read data buffer"); 49 static int g_zero_byte = 0; 50 SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0, 51 "Byte (octet) value to clear the buffers with"); 52 53 static void 54 g_zero_start(struct bio *bp) 55 { 56 int error = ENXIO; 57 58 switch (bp->bio_cmd) { 59 case BIO_READ: 60 if (g_zero_clear) 61 memset(bp->bio_data, g_zero_byte, bp->bio_length); 62 /* FALLTHROUGH */ 63 case BIO_DELETE: 64 case BIO_WRITE: 65 bp->bio_completed = bp->bio_length; 66 error = 0; 67 break; 68 case BIO_GETATTR: 69 default: 70 error = EOPNOTSUPP; 71 break; 72 } 73 g_io_deliver(bp, error); 74 } 75 76 static void 77 g_zero_init(struct g_class *mp) 78 { 79 struct g_geom *gp; 80 struct g_provider *pp; 81 82 g_topology_assert(); 83 gp = g_new_geomf(mp, "gzero"); 84 gp->start = g_zero_start; 85 gp->access = g_std_access; 86 pp = g_new_providerf(gp, "%s", gp->name); 87 pp->mediasize = 1152921504606846976LLU; 88 pp->sectorsize = 512; 89 g_error_provider(pp, 0); 90 } 91 92 static int 93 g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, 94 struct g_geom *gp) 95 { 96 struct g_provider *pp; 97 98 g_topology_assert(); 99 if (gp == NULL) 100 return (0); 101 pp = LIST_FIRST(&gp->provider); 102 if (pp == NULL) 103 return (0); 104 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) 105 return (EBUSY); 106 g_wither_geom(gp, ENXIO); 107 return (EBUSY); 108 } 109 110 static struct g_class g_zero_class = { 111 .name = G_ZERO_CLASS_NAME, 112 .version = G_VERSION, 113 .init = g_zero_init, 114 .destroy_geom = g_zero_destroy_geom 115 }; 116 117 DECLARE_GEOM_CLASS(g_zero_class, g_zero); 118