294 lines
7.1 KiB
C
294 lines
7.1 KiB
C
/*
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* xenstore_dev.c
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*
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* Driver giving user-space access to the kernel's connection to the
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* XenStore service.
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*
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* Copyright (c) 2005, Christian Limpach
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* Copyright (c) 2005, Rusty Russell, IBM Corporation
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*
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* This file may be distributed separately from the Linux kernel, or
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* incorporated into other software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/cdefs.h>
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#include <sys/errno.h>
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#include <sys/uio.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/conf.h>
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#include <sys/module.h>
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#include <xen/xen-os.h>
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#include <xen/hypervisor.h>
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#include <xen/xenstore/xenstorevar.h>
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#include <xen/xenstore/xenstore_internal.h>
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struct xs_dev_transaction {
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LIST_ENTRY(xs_dev_transaction) list;
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struct xs_transaction handle;
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};
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struct xs_dev_data {
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/* In-progress transaction. */
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LIST_HEAD(xdd_list_head, xs_dev_transaction) transactions;
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/* Partial request. */
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unsigned int len;
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union {
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struct xsd_sockmsg msg;
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char buffer[PAGE_SIZE];
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} u;
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/* Response queue. */
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#define MASK_READ_IDX(idx) ((idx)&(PAGE_SIZE-1))
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char read_buffer[PAGE_SIZE];
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unsigned int read_cons, read_prod;
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};
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static int
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xs_dev_read(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int error;
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struct xs_dev_data *u;
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error = devfs_get_cdevpriv((void **)&u);
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if (error != 0)
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return (error);
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while (u->read_prod == u->read_cons) {
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error = tsleep(u, PCATCH, "xsdread", hz/10);
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if (error && error != EWOULDBLOCK)
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return (error);
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}
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while (uio->uio_resid > 0) {
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if (u->read_cons == u->read_prod)
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break;
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error = uiomove(&u->read_buffer[MASK_READ_IDX(u->read_cons)],
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1, uio);
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if (error)
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return (error);
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u->read_cons++;
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}
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return (0);
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}
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static void
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xs_queue_reply(struct xs_dev_data *u, char *data, unsigned int len)
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{
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int i;
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for (i = 0; i < len; i++, u->read_prod++)
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u->read_buffer[MASK_READ_IDX(u->read_prod)] = data[i];
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KASSERT((u->read_prod - u->read_cons) <= sizeof(u->read_buffer),
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("xenstore reply too big"));
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wakeup(u);
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}
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static int
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xs_dev_write(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int error;
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struct xs_dev_data *u;
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struct xs_dev_transaction *trans;
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void *reply;
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int len = uio->uio_resid;
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error = devfs_get_cdevpriv((void **)&u);
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if (error != 0)
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return (error);
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if ((len + u->len) > sizeof(u->u.buffer))
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return (EINVAL);
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error = uiomove(u->u.buffer + u->len, len, uio);
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if (error)
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return (error);
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u->len += len;
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if (u->len < (sizeof(u->u.msg) + u->u.msg.len))
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return (0);
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switch (u->u.msg.type) {
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case XS_TRANSACTION_START:
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case XS_TRANSACTION_END:
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case XS_DIRECTORY:
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case XS_READ:
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case XS_GET_PERMS:
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case XS_RELEASE:
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case XS_GET_DOMAIN_PATH:
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case XS_WRITE:
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case XS_MKDIR:
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case XS_RM:
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case XS_SET_PERMS:
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error = xs_dev_request_and_reply(&u->u.msg, &reply);
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if (!error) {
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if (u->u.msg.type == XS_TRANSACTION_START) {
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trans = malloc(sizeof(*trans), M_XENSTORE,
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M_WAITOK);
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trans->handle.id = strtoul(reply, NULL, 0);
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LIST_INSERT_HEAD(&u->transactions, trans, list);
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} else if (u->u.msg.type == XS_TRANSACTION_END) {
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LIST_FOREACH(trans, &u->transactions, list)
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if (trans->handle.id == u->u.msg.tx_id)
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break;
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#if 0 /* XXX does this mean the list is empty? */
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BUG_ON(&trans->list == &u->transactions);
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#endif
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LIST_REMOVE(trans, list);
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free(trans, M_XENSTORE);
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}
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xs_queue_reply(u, (char *)&u->u.msg, sizeof(u->u.msg));
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xs_queue_reply(u, (char *)reply, u->u.msg.len);
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free(reply, M_XENSTORE);
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}
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break;
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default:
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error = EINVAL;
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break;
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}
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if (error == 0)
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u->len = 0;
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return (error);
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}
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static void
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xs_dev_dtor(void *arg)
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{
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struct xs_dev_data *u = arg;
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struct xs_dev_transaction *trans, *tmp;
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LIST_FOREACH_SAFE(trans, &u->transactions, list, tmp) {
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xs_transaction_end(trans->handle, 1);
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LIST_REMOVE(trans, list);
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free(trans, M_XENSTORE);
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}
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free(u, M_XENSTORE);
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}
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static int
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xs_dev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
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{
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struct xs_dev_data *u;
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int error;
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u = malloc(sizeof(*u), M_XENSTORE, M_WAITOK|M_ZERO);
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LIST_INIT(&u->transactions);
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error = devfs_set_cdevpriv(u, xs_dev_dtor);
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if (error != 0)
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free(u, M_XENSTORE);
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return (error);
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}
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static struct cdevsw xs_dev_cdevsw = {
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.d_version = D_VERSION,
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.d_read = xs_dev_read,
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.d_write = xs_dev_write,
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.d_open = xs_dev_open,
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.d_name = "xs_dev",
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};
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/*------------------ Private Device Attachment Functions --------------------*/
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/**
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* \brief Identify instances of this device type in the system.
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*
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* \param driver The driver performing this identify action.
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* \param parent The NewBus parent device for any devices this method adds.
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*/
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static void
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xs_dev_identify(driver_t *driver __unused, device_t parent)
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{
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/*
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* A single device instance for our driver is always present
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* in a system operating under Xen.
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*/
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BUS_ADD_CHILD(parent, 0, driver->name, 0);
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}
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/**
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* \brief Probe for the existence of the Xenstore device
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*
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* \param dev NewBus device_t for this instance.
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*
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* \return Always returns 0 indicating success.
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*/
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static int
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xs_dev_probe(device_t dev)
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{
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device_set_desc(dev, "Xenstore user-space device");
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return (0);
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}
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/**
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* \brief Attach the Xenstore device.
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*
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* \param dev NewBus device_t for this instance.
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*
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* \return On success, 0. Otherwise an errno value indicating the
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* type of failure.
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*/
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static int
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xs_dev_attach(device_t dev)
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{
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struct cdev *xs_cdev;
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xs_cdev = make_dev_credf(MAKEDEV_ETERNAL, &xs_dev_cdevsw, 0, NULL,
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UID_ROOT, GID_WHEEL, 0400, "xen/xenstore");
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if (xs_cdev == NULL)
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return (EINVAL);
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return (0);
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}
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/*-------------------- Private Device Attachment Data -----------------------*/
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static device_method_t xs_dev_methods[] = {
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/* Device interface */
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DEVMETHOD(device_identify, xs_dev_identify),
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DEVMETHOD(device_probe, xs_dev_probe),
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DEVMETHOD(device_attach, xs_dev_attach),
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DEVMETHOD_END
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};
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DEFINE_CLASS_0(xs_dev, xs_dev_driver, xs_dev_methods, 0);
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devclass_t xs_dev_devclass;
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DRIVER_MODULE(xs_dev, xenstore, xs_dev_driver, xs_dev_devclass,
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NULL, NULL);
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