1 /*- 2 * Copyright (c) 2000 Mark R. V. Murray & Jeroen C. van Gelderen 3 * Copyright (c) 2001-2004 Mark R. V. Murray 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer 11 * in this position and unchanged. 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 ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/conf.h> 35 #include <sys/uio.h> 36 #include <sys/kernel.h> 37 #include <sys/malloc.h> 38 #include <sys/module.h> 39 #include <sys/priv.h> 40 #include <sys/disk.h> 41 #include <sys/bus.h> 42 #include <sys/filio.h> 43 44 #include <machine/bus.h> 45 #include <machine/vmparam.h> 46 47 /* For use with destroy_dev(9). */ 48 static struct cdev *null_dev; 49 static struct cdev *zero_dev; 50 51 static d_write_t null_write; 52 static d_ioctl_t null_ioctl; 53 static d_ioctl_t zero_ioctl; 54 static d_read_t zero_read; 55 56 static struct cdevsw null_cdevsw = { 57 .d_version = D_VERSION, 58 .d_read = (d_read_t *)nullop, 59 .d_write = null_write, 60 .d_ioctl = null_ioctl, 61 .d_name = "null", 62 }; 63 64 static struct cdevsw zero_cdevsw = { 65 .d_version = D_VERSION, 66 .d_read = zero_read, 67 .d_write = null_write, 68 .d_ioctl = zero_ioctl, 69 .d_name = "zero", 70 .d_flags = D_MMAP_ANON, 71 }; 72 73 /* ARGSUSED */ 74 static int 75 null_write(struct cdev *dev __unused, struct uio *uio, int flags __unused) 76 { 77 uio->uio_resid = 0; 78 79 return (0); 80 } 81 82 /* ARGSUSED */ 83 static int 84 null_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t data __unused, 85 int flags __unused, struct thread *td) 86 { 87 int error; 88 error = 0; 89 90 switch (cmd) { 91 case DIOCSKERNELDUMP: 92 error = priv_check(td, PRIV_SETDUMPER); 93 if (error == 0) 94 error = set_dumper(NULL, NULL); 95 break; 96 case FIONBIO: 97 break; 98 case FIOASYNC: 99 if (*(int *)data != 0) 100 error = EINVAL; 101 break; 102 default: 103 error = ENOIOCTL; 104 } 105 return (error); 106 } 107 108 /* ARGSUSED */ 109 static int 110 zero_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t data __unused, 111 int flags __unused, struct thread *td) 112 { 113 int error; 114 error = 0; 115 116 switch (cmd) { 117 case FIONBIO: 118 break; 119 case FIOASYNC: 120 if (*(int *)data != 0) 121 error = EINVAL; 122 break; 123 default: 124 error = ENOIOCTL; 125 } 126 return (error); 127 } 128 129 130 /* ARGSUSED */ 131 static int 132 zero_read(struct cdev *dev __unused, struct uio *uio, int flags __unused) 133 { 134 void *zbuf; 135 ssize_t len; 136 int error = 0; 137 138 KASSERT(uio->uio_rw == UIO_READ, 139 ("Can't be in %s for write", __func__)); 140 zbuf = __DECONST(void *, zero_region); 141 while (uio->uio_resid > 0 && error == 0) { 142 len = uio->uio_resid; 143 if (len > ZERO_REGION_SIZE) 144 len = ZERO_REGION_SIZE; 145 error = uiomove(zbuf, len, uio); 146 } 147 148 return (error); 149 } 150 151 /* ARGSUSED */ 152 static int 153 null_modevent(module_t mod __unused, int type, void *data __unused) 154 { 155 switch(type) { 156 case MOD_LOAD: 157 if (bootverbose) 158 printf("null: <null device, zero device>\n"); 159 null_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &null_cdevsw, 0, 160 NULL, UID_ROOT, GID_WHEEL, 0666, "null"); 161 zero_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &zero_cdevsw, 0, 162 NULL, UID_ROOT, GID_WHEEL, 0666, "zero"); 163 break; 164 165 case MOD_UNLOAD: 166 destroy_dev(null_dev); 167 destroy_dev(zero_dev); 168 break; 169 170 case MOD_SHUTDOWN: 171 break; 172 173 default: 174 return (EOPNOTSUPP); 175 } 176 177 return (0); 178 } 179 180 DEV_MODULE(null, null_modevent, NULL); 181 MODULE_VERSION(null, 1); 182