1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 #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 #define G_ZERO_CLASS_NAME "ZERO" 42 43 static int g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS); 44 45 SYSCTL_DECL(_kern_geom); 46 static SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 47 "GEOM_ZERO stuff"); 48 static int g_zero_clear = 1; 49 SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear, 50 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &g_zero_clear, 0, 51 g_zero_clear_sysctl, "I", 52 "Clear read data buffer"); 53 static int g_zero_byte = 0; 54 SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0, 55 "Byte (octet) value to clear the buffers with"); 56 57 static struct g_provider *gpp; 58 59 static int 60 g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS) 61 { 62 int error; 63 64 error = sysctl_handle_int(oidp, &g_zero_clear, 0, req); 65 if (error != 0 || req->newptr == NULL) 66 return (error); 67 if (gpp == NULL) 68 return (ENXIO); 69 if (g_zero_clear) 70 gpp->flags &= ~G_PF_ACCEPT_UNMAPPED; 71 else 72 gpp->flags |= G_PF_ACCEPT_UNMAPPED; 73 return (0); 74 } 75 76 static void 77 g_zero_start(struct bio *bp) 78 { 79 int error = ENXIO; 80 81 switch (bp->bio_cmd) { 82 case BIO_READ: 83 if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0) 84 memset(bp->bio_data, g_zero_byte, bp->bio_length); 85 /* FALLTHROUGH */ 86 case BIO_DELETE: 87 case BIO_WRITE: 88 bp->bio_completed = bp->bio_length; 89 error = 0; 90 break; 91 case BIO_GETATTR: 92 default: 93 error = EOPNOTSUPP; 94 break; 95 } 96 g_io_deliver(bp, error); 97 } 98 99 static void 100 g_zero_init(struct g_class *mp) 101 { 102 struct g_geom *gp; 103 struct g_provider *pp; 104 105 g_topology_assert(); 106 gp = g_new_geomf(mp, "gzero"); 107 gp->start = g_zero_start; 108 gp->access = g_std_access; 109 gpp = pp = g_new_providerf(gp, "%s", gp->name); 110 pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE; 111 if (!g_zero_clear) 112 pp->flags |= G_PF_ACCEPT_UNMAPPED; 113 pp->mediasize = 1152921504606846976LLU; 114 pp->sectorsize = 512; 115 g_error_provider(pp, 0); 116 } 117 118 static int 119 g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, 120 struct g_geom *gp) 121 { 122 struct g_provider *pp; 123 124 g_topology_assert(); 125 if (gp == NULL) 126 return (0); 127 pp = LIST_FIRST(&gp->provider); 128 if (pp == NULL) 129 return (0); 130 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) 131 return (EBUSY); 132 gpp = NULL; 133 g_wither_geom(gp, ENXIO); 134 return (0); 135 } 136 137 static struct g_class g_zero_class = { 138 .name = G_ZERO_CLASS_NAME, 139 .version = G_VERSION, 140 .init = g_zero_init, 141 .destroy_geom = g_zero_destroy_geom 142 }; 143 144 DECLARE_GEOM_CLASS(g_zero_class, g_zero); 145 MODULE_VERSION(geom_zero, 0); 146