1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/bio.h> 34 #include <sys/kernel.h> 35 #include <sys/limits.h> 36 #include <sys/malloc.h> 37 #include <sys/queue.h> 38 #include <sys/sysctl.h> 39 #include <sys/systm.h> 40 41 #include <geom/geom.h> 42 43 44 #define G_ZERO_CLASS_NAME "ZERO" 45 46 static int g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS); 47 48 SYSCTL_DECL(_kern_geom); 49 static SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 50 "GEOM_ZERO stuff"); 51 static int g_zero_clear = 1; 52 SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear, 53 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, &g_zero_clear, 0, 54 g_zero_clear_sysctl, "I", 55 "Clear read data buffer"); 56 static int g_zero_byte = 0; 57 SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0, 58 "Byte (octet) value to clear the buffers with"); 59 60 static struct g_provider *gpp; 61 62 static int 63 g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS) 64 { 65 int error; 66 67 error = sysctl_handle_int(oidp, &g_zero_clear, 0, req); 68 if (error != 0 || req->newptr == NULL) 69 return (error); 70 if (gpp == NULL) 71 return (ENXIO); 72 if (g_zero_clear) 73 gpp->flags &= ~G_PF_ACCEPT_UNMAPPED; 74 else 75 gpp->flags |= G_PF_ACCEPT_UNMAPPED; 76 return (0); 77 } 78 79 static void 80 g_zero_start(struct bio *bp) 81 { 82 int error = ENXIO; 83 84 switch (bp->bio_cmd) { 85 case BIO_READ: 86 if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0) 87 memset(bp->bio_data, g_zero_byte, bp->bio_length); 88 /* FALLTHROUGH */ 89 case BIO_DELETE: 90 case BIO_WRITE: 91 bp->bio_completed = bp->bio_length; 92 error = 0; 93 break; 94 case BIO_GETATTR: 95 default: 96 error = EOPNOTSUPP; 97 break; 98 } 99 g_io_deliver(bp, error); 100 } 101 102 static void 103 g_zero_init(struct g_class *mp) 104 { 105 struct g_geom *gp; 106 struct g_provider *pp; 107 108 g_topology_assert(); 109 gp = g_new_geomf(mp, "gzero"); 110 gp->start = g_zero_start; 111 gp->access = g_std_access; 112 gpp = pp = g_new_providerf(gp, "%s", gp->name); 113 pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE; 114 if (!g_zero_clear) 115 pp->flags |= G_PF_ACCEPT_UNMAPPED; 116 pp->mediasize = 1152921504606846976LLU; 117 pp->sectorsize = 512; 118 g_error_provider(pp, 0); 119 } 120 121 static int 122 g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, 123 struct g_geom *gp) 124 { 125 struct g_provider *pp; 126 127 g_topology_assert(); 128 if (gp == NULL) 129 return (0); 130 pp = LIST_FIRST(&gp->provider); 131 if (pp == NULL) 132 return (0); 133 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) 134 return (EBUSY); 135 gpp = NULL; 136 g_wither_geom(gp, ENXIO); 137 return (0); 138 } 139 140 static struct g_class g_zero_class = { 141 .name = G_ZERO_CLASS_NAME, 142 .version = G_VERSION, 143 .init = g_zero_init, 144 .destroy_geom = g_zero_destroy_geom 145 }; 146 147 DECLARE_GEOM_CLASS(g_zero_class, g_zero); 148 MODULE_VERSION(geom_zero, 0); 149