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, 0, 50 "GEOM_ZERO stuff"); 51 static int g_zero_clear = 1; 52 SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, 53 &g_zero_clear, 0, g_zero_clear_sysctl, "I", "Clear read data buffer"); 54 static int g_zero_byte = 0; 55 SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0, 56 "Byte (octet) value to clear the buffers with"); 57 58 static struct g_provider *gpp; 59 60 static int 61 g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS) 62 { 63 int error; 64 65 error = sysctl_handle_int(oidp, &g_zero_clear, 0, req); 66 if (error != 0 || req->newptr == NULL) 67 return (error); 68 if (gpp == NULL) 69 return (ENXIO); 70 if (g_zero_clear) 71 gpp->flags &= ~G_PF_ACCEPT_UNMAPPED; 72 else 73 gpp->flags |= G_PF_ACCEPT_UNMAPPED; 74 return (0); 75 } 76 77 static void 78 g_zero_start(struct bio *bp) 79 { 80 int error = ENXIO; 81 82 switch (bp->bio_cmd) { 83 case BIO_READ: 84 if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0) 85 memset(bp->bio_data, g_zero_byte, bp->bio_length); 86 /* FALLTHROUGH */ 87 case BIO_DELETE: 88 case BIO_WRITE: 89 bp->bio_completed = bp->bio_length; 90 error = 0; 91 break; 92 case BIO_GETATTR: 93 default: 94 error = EOPNOTSUPP; 95 break; 96 } 97 g_io_deliver(bp, error); 98 } 99 100 static void 101 g_zero_init(struct g_class *mp) 102 { 103 struct g_geom *gp; 104 struct g_provider *pp; 105 106 g_topology_assert(); 107 gp = g_new_geomf(mp, "gzero"); 108 gp->start = g_zero_start; 109 gp->access = g_std_access; 110 gpp = pp = g_new_providerf(gp, "%s", gp->name); 111 pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE; 112 if (!g_zero_clear) 113 pp->flags |= G_PF_ACCEPT_UNMAPPED; 114 pp->mediasize = 1152921504606846976LLU; 115 pp->sectorsize = 512; 116 g_error_provider(pp, 0); 117 } 118 119 static int 120 g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, 121 struct g_geom *gp) 122 { 123 struct g_provider *pp; 124 125 g_topology_assert(); 126 if (gp == NULL) 127 return (0); 128 pp = LIST_FIRST(&gp->provider); 129 if (pp == NULL) 130 return (0); 131 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) 132 return (EBUSY); 133 gpp = NULL; 134 g_wither_geom(gp, ENXIO); 135 return (0); 136 } 137 138 static struct g_class g_zero_class = { 139 .name = G_ZERO_CLASS_NAME, 140 .version = G_VERSION, 141 .init = g_zero_init, 142 .destroy_geom = g_zero_destroy_geom 143 }; 144 145 DECLARE_GEOM_CLASS(g_zero_class, g_zero); 146 MODULE_VERSION(geom_zero, 0); 147