353 lines
8.4 KiB
C
353 lines
8.4 KiB
C
/* $NetBSD: xenbus_dev.c,v 1.8 2009/03/16 06:17:39 cegger Exp $ */
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/*
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* xenbus_dev.c
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*
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* Driver giving user-space access to the kernel's xenbus connection
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* to xenstore.
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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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__KERNEL_RCSID(0, "$NetBSD: xenbus_dev.c,v 1.8 2009/03/16 06:17:39 cegger Exp $");
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#include "opt_xen.h"
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#include <sys/types.h>
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#include <sys/null.h>
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#include <sys/errno.h>
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#include <sys/malloc.h>
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/systm.h>
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#include <sys/dirent.h>
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#include <sys/stat.h>
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#include <sys/tree.h>
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#include <sys/vnode.h>
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#include <miscfs/specfs/specdev.h>
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#include <miscfs/kernfs/kernfs.h>
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#include <xen/kernfs_machdep.h>
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#include <xen/hypervisor.h>
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#include <xen/xenbus.h>
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#include "xenbus_comms.h"
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static int xenbus_dev_read(void *);
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static int xenbus_dev_write(void *);
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static int xenbus_dev_open(void *);
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static int xenbus_dev_close(void *);
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static int xsd_port_read(void *);
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struct xenbus_dev_transaction {
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SLIST_ENTRY(xenbus_dev_transaction) trans_next;
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struct xenbus_transaction *handle;
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};
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#define DIR_MODE (S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
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#define PRIVCMD_MODE (S_IRUSR | S_IWUSR)
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static const struct kernfs_fileop xenbus_fileops[] = {
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{ .kf_fileop = KERNFS_FILEOP_OPEN, .kf_vop = xenbus_dev_open },
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{ .kf_fileop = KERNFS_FILEOP_CLOSE, .kf_vop = xenbus_dev_close },
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{ .kf_fileop = KERNFS_FILEOP_READ, .kf_vop = xenbus_dev_read },
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{ .kf_fileop = KERNFS_FILEOP_WRITE, .kf_vop = xenbus_dev_write },
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};
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#define XSD_MODE (S_IRUSR)
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static const struct kernfs_fileop xsd_port_fileops[] = {
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{ .kf_fileop = KERNFS_FILEOP_READ, .kf_vop = xsd_port_read },
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};
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void
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xenbus_kernfs_init(void)
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{
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kernfs_entry_t *dkt;
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kfstype kfst;
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kfst = KERNFS_ALLOCTYPE(xenbus_fileops);
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KERNFS_ALLOCENTRY(dkt, M_TEMP, M_WAITOK);
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KERNFS_INITENTRY(dkt, DT_REG, "xenbus", NULL, kfst, VREG,
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PRIVCMD_MODE);
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kernfs_addentry(kernxen_pkt, dkt);
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kfst = KERNFS_ALLOCTYPE(xsd_port_fileops);
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KERNFS_ALLOCENTRY(dkt, M_TEMP, M_WAITOK);
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KERNFS_INITENTRY(dkt, DT_REG, "xsd_port", NULL, kfst, VREG, XSD_MODE);
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kernfs_addentry(kernxen_pkt, dkt);
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}
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struct xenbus_dev_data {
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#define BUFFER_SIZE (PAGE_SIZE)
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#define MASK_READ_IDX(idx) ((idx)&(BUFFER_SIZE-1))
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/* In-progress transaction. */
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SLIST_HEAD(, xenbus_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[BUFFER_SIZE];
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} u;
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/* Response queue. */
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char read_buffer[BUFFER_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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xenbus_dev_read(void *v)
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{
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struct vop_read_args /* {
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struct vnode *a_vp;
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struct uio *a_uio;
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int a_ioflag;
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struct ucred *a_cred;
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} */ *ap = v;
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struct kernfs_node *kfs = VTOKERN(ap->a_vp);
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struct uio *uio = ap->a_uio;
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struct xenbus_dev_data *u = kfs->kfs_v;
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int err;
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off_t offset;
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int s = spltty();
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while (u->read_prod == u->read_cons) {
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err = tsleep(u, PRIBIO | PCATCH, "xbrd", 0);
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if (err)
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goto end;
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}
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offset = uio->uio_offset;
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if (u->read_cons > u->read_prod) {
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err = uiomove(&u->read_buffer[MASK_READ_IDX(u->read_cons)],
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0U - u->read_cons, uio);
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if (err)
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goto end;
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u->read_cons += (uio->uio_offset - offset);
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offset = uio->uio_offset;
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}
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err = uiomove(&u->read_buffer[MASK_READ_IDX(u->read_cons)],
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u->read_prod - u->read_cons, uio);
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if (err == 0)
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u->read_cons += (uio->uio_offset - offset);
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end:
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splx(s);
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return err;
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}
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static void
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queue_reply(struct xenbus_dev_data *u,
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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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wakeup(&u);
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}
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static int
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xenbus_dev_write(void *v)
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{
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struct vop_write_args /* {
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struct vnode *a_vp;
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struct uio *a_uio;
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int a_ioflag;
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struct ucred *a_cred;
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} */ *ap = v;
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struct kernfs_node *kfs = VTOKERN(ap->a_vp);
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struct uio *uio = ap->a_uio;
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struct xenbus_dev_data *u = kfs->kfs_v;
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struct xenbus_dev_transaction *trans;
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void *reply;
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int err;
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size_t size;
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if (uio->uio_offset < 0)
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return EINVAL;
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size = uio->uio_resid;
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if ((size + u->len) > sizeof(u->u.buffer))
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return EINVAL;
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err = uiomove(u->u.buffer + u->len, sizeof(u->u.buffer) - u->len, uio);
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if (err)
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return err;
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u->len += size;
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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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err = xenbus_dev_request_and_reply(&u->u.msg, &reply);
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if (err == 0) {
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if (u->u.msg.type == XS_TRANSACTION_START) {
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trans = malloc(sizeof(*trans), M_DEVBUF,
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M_WAITOK);
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trans->handle = (struct xenbus_transaction *)
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strtoul(reply, NULL, 0);
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SLIST_INSERT_HEAD(&u->transactions,
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trans, trans_next);
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} else if (u->u.msg.type == XS_TRANSACTION_END) {
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SLIST_FOREACH(trans, &u->transactions,
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trans_next) {
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if ((unsigned long)trans->handle ==
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(unsigned long)u->u.msg.tx_id)
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break;
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}
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KASSERT(trans != NULL);
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SLIST_REMOVE(&u->transactions, trans,
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xenbus_dev_transaction, trans_next);
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free(trans, M_DEVBUF);
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}
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queue_reply(u, (char *)&u->u.msg, sizeof(u->u.msg));
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queue_reply(u, (char *)reply, u->u.msg.len);
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free(reply, M_DEVBUF);
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}
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break;
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default:
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err = EINVAL;
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break;
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}
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if (err == 0) {
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u->len = 0;
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}
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return err;
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}
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static int
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xenbus_dev_open(void *v)
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{
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struct vop_open_args /* {
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struct vnode *a_vp;
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int a_mode;
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struct ucred *a_cred;
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} */ *ap = v;
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struct kernfs_node *kfs = VTOKERN(ap->a_vp);
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struct xenbus_dev_data *u;
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if (xen_start_info.store_evtchn == 0)
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return ENOENT;
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u = malloc(sizeof(*u), M_DEVBUF, M_WAITOK);
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if (u == NULL)
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return ENOMEM;
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memset(u, 0, sizeof(*u));
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SLIST_INIT(&u->transactions);
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kfs->kfs_v = u;
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return 0;
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}
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static int
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xenbus_dev_close(void *v)
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{
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struct vop_close_args /* {
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struct vnode *a_vp;
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int a_fflag;
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struct ucred *a_cred;
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} */ *ap = v;
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struct kernfs_node *kfs = VTOKERN(ap->a_vp);
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struct xenbus_dev_data *u = kfs->kfs_v;
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struct xenbus_dev_transaction *trans;
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while (!SLIST_EMPTY(&u->transactions)) {
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trans = SLIST_FIRST(&u->transactions);
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xenbus_transaction_end(trans->handle, 1);
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SLIST_REMOVE_HEAD(&u->transactions, trans_next);
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free(trans, M_DEVBUF);
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}
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free(u, M_DEVBUF);
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kfs->kfs_v = NULL;
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return 0;
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}
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#define LD_STRLEN 21 /* a 64bit integer needs 20 digits in base10 */
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static int
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xsd_port_read(void *v)
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{
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struct vop_read_args /* {
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struct vnode *a_vp;
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struct uio *a_uio;
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int a_ioflag;
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struct ucred *a_cred;
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} */ *ap = v;
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struct uio *uio = ap->a_uio;
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int off, error;
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size_t len;
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char strbuf[LD_STRLEN], *bf;
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off = (int)uio->uio_offset;
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if (off < 0)
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return EINVAL;
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len = snprintf(strbuf, sizeof(strbuf), "%ld\n",
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(long)xen_start_info.store_evtchn);
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if (off >= len) {
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bf = strbuf;
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len = 0;
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} else {
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bf = &strbuf[off];
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len -= off;
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}
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error = uiomove(bf, len, uio);
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return error;
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}
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/*
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* Local variables:
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* c-file-style: "linux"
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* indent-tabs-mode: t
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* c-indent-level: 8
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* c-basic-offset: 8
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* tab-width: 8
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* End:
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*/
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