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 #define G_ZERO_CLASS_NAME "ZERO" 44 45 static int g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS); 46 47 SYSCTL_DECL(_kern_geom); 48 static SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 49 "GEOM_ZERO stuff"); 50 static int g_zero_clear = 1; 51 SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear, 52 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &g_zero_clear, 0, 53 g_zero_clear_sysctl, "I", 54 "Clear read data buffer"); 55 static int g_zero_byte = 0; 56 SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0, 57 "Byte (octet) value to clear the buffers with"); 58 59 static struct g_provider *gpp; 60 61 static int 62 g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS) 63 { 64 int error; 65 66 error = sysctl_handle_int(oidp, &g_zero_clear, 0, req); 67 if (error != 0 || req->newptr == NULL) 68 return (error); 69 if (gpp == NULL) 70 return (ENXIO); 71 if (g_zero_clear) 72 gpp->flags &= ~G_PF_ACCEPT_UNMAPPED; 73 else 74 gpp->flags |= G_PF_ACCEPT_UNMAPPED; 75 return (0); 76 } 77 78 static void 79 g_zero_start(struct bio *bp) 80 { 81 int error = ENXIO; 82 83 switch (bp->bio_cmd) { 84 case BIO_READ: 85 if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0) 86 memset(bp->bio_data, g_zero_byte, bp->bio_length); 87 /* FALLTHROUGH */ 88 case BIO_DELETE: 89 case BIO_WRITE: 90 bp->bio_completed = bp->bio_length; 91 error = 0; 92 break; 93 case BIO_GETATTR: 94 default: 95 error = EOPNOTSUPP; 96 break; 97 } 98 g_io_deliver(bp, error); 99 } 100 101 static void 102 g_zero_init(struct g_class *mp) 103 { 104 struct g_geom *gp; 105 struct g_provider *pp; 106 107 g_topology_assert(); 108 gp = g_new_geomf(mp, "gzero"); 109 gp->start = g_zero_start; 110 gp->access = g_std_access; 111 gpp = pp = g_new_providerf(gp, "%s", gp->name); 112 pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE; 113 if (!g_zero_clear) 114 pp->flags |= G_PF_ACCEPT_UNMAPPED; 115 pp->mediasize = 1152921504606846976LLU; 116 pp->sectorsize = 512; 117 g_error_provider(pp, 0); 118 } 119 120 static int 121 g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, 122 struct g_geom *gp) 123 { 124 struct g_provider *pp; 125 126 g_topology_assert(); 127 if (gp == NULL) 128 return (0); 129 pp = LIST_FIRST(&gp->provider); 130 if (pp == NULL) 131 return (0); 132 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) 133 return (EBUSY); 134 gpp = NULL; 135 g_wither_geom(gp, ENXIO); 136 return (0); 137 } 138 139 static struct g_class g_zero_class = { 140 .name = G_ZERO_CLASS_NAME, 141 .version = G_VERSION, 142 .init = g_zero_init, 143 .destroy_geom = g_zero_destroy_geom 144 }; 145 146 DECLARE_GEOM_CLASS(g_zero_class, g_zero); 147 MODULE_VERSION(geom_zero, 0); 148