diff options
Diffstat (limited to 'sys/geom/zero')
| -rw-r--r-- | sys/geom/zero/g_zero.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/sys/geom/zero/g_zero.c b/sys/geom/zero/g_zero.c new file mode 100644 index 000000000000..ab8ca8d6b5ba --- /dev/null +++ b/sys/geom/zero/g_zero.c @@ -0,0 +1,146 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/bio.h> +#include <sys/kernel.h> +#include <sys/limits.h> +#include <sys/malloc.h> +#include <sys/queue.h> +#include <sys/sysctl.h> +#include <sys/systm.h> + +#include <geom/geom.h> + + +#define G_ZERO_CLASS_NAME "ZERO" + +static int g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS); + +SYSCTL_DECL(_kern_geom); +static SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW, 0, + "GEOM_ZERO stuff"); +static int g_zero_clear = 1; +SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear, CTLTYPE_INT|CTLFLAG_RW, + &g_zero_clear, 0, g_zero_clear_sysctl, "I", "Clear read data buffer"); +static int g_zero_byte = 0; +SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0, + "Byte (octet) value to clear the buffers with"); + +static struct g_provider *gpp; + +static int +g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS) +{ + int error; + + error = sysctl_handle_int(oidp, &g_zero_clear, 0, req); + if (error != 0 || req->newptr == NULL) + return (error); + if (gpp == NULL) + return (ENXIO); + if (g_zero_clear) + gpp->flags &= ~G_PF_ACCEPT_UNMAPPED; + else + gpp->flags |= G_PF_ACCEPT_UNMAPPED; + return (0); +} + +static void +g_zero_start(struct bio *bp) +{ + int error = ENXIO; + + switch (bp->bio_cmd) { + case BIO_READ: + if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0) + memset(bp->bio_data, g_zero_byte, bp->bio_length); + /* FALLTHROUGH */ + case BIO_DELETE: + case BIO_WRITE: + bp->bio_completed = bp->bio_length; + error = 0; + break; + case BIO_GETATTR: + default: + error = EOPNOTSUPP; + break; + } + g_io_deliver(bp, error); +} + +static void +g_zero_init(struct g_class *mp) +{ + struct g_geom *gp; + struct g_provider *pp; + + g_topology_assert(); + gp = g_new_geomf(mp, "gzero"); + gp->start = g_zero_start; + gp->access = g_std_access; + gpp = pp = g_new_providerf(gp, "%s", gp->name); + pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE; + if (!g_zero_clear) + pp->flags |= G_PF_ACCEPT_UNMAPPED; + pp->mediasize = 1152921504606846976LLU; + pp->sectorsize = 512; + g_error_provider(pp, 0); +} + +static int +g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, + struct g_geom *gp) +{ + struct g_provider *pp; + + g_topology_assert(); + if (gp == NULL) + return (0); + pp = LIST_FIRST(&gp->provider); + if (pp == NULL) + return (0); + if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) + return (EBUSY); + gpp = NULL; + g_wither_geom(gp, ENXIO); + return (0); +} + +static struct g_class g_zero_class = { + .name = G_ZERO_CLASS_NAME, + .version = G_VERSION, + .init = g_zero_init, + .destroy_geom = g_zero_destroy_geom +}; + +DECLARE_GEOM_CLASS(g_zero_class, g_zero); +MODULE_VERSION(geom_zero, 0); |