282 lines
6.8 KiB
C
282 lines
6.8 KiB
C
/* $NetBSD: xenbus_client.c,v 1.10 2009/04/28 05:44:43 cegger Exp $ */
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/******************************************************************************
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* Client-facing interface for the Xenbus driver. In other words, the
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* interface between the Xenbus and the device-specific code, be it the
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* frontend or the backend of that driver.
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*
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* Copyright (C) 2005 XenSource Ltd
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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_client.c,v 1.10 2009/04/28 05:44:43 cegger Exp $");
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#if 0
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#define DPRINTK(fmt, args...) \
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printk("xenbus_client (%s:%d) " fmt ".\n", __func__, __LINE__, ##args)
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#else
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#define DPRINTK(fmt, args...) ((void)0)
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#endif
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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/systm.h>
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#include <machine/stdarg.h>
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#include <xen/xen.h>
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#include <xen/hypervisor.h>
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#include <xen/evtchn.h>
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#include <xen/xenbus.h>
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#include <xen/granttables.h>
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int
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xenbus_watch_path(struct xenbus_device *dev, char *path,
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struct xenbus_watch *watch,
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void (*callback)(struct xenbus_watch *,
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const char **, unsigned int))
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{
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int err;
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watch->node = path;
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watch->xbw_callback = callback;
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err = register_xenbus_watch(watch);
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if (err) {
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watch->node = NULL;
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watch->xbw_callback = NULL;
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xenbus_dev_fatal(dev, err, "adding watch on %s", path);
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}
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err = 0;
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return err;
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}
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int
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xenbus_watch_path2(struct xenbus_device *dev, const char *path,
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const char *path2, struct xenbus_watch *watch,
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void (*callback)(struct xenbus_watch *,
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const char **, unsigned int))
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{
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int err;
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char *state;
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DPRINTK("xenbus_watch_path2 path %s path2 %s\n", path, path2);
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state =
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malloc(strlen(path) + 1 + strlen(path2) + 1, M_DEVBUF,
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M_NOWAIT);
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if (!state) {
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xenbus_dev_fatal(dev, ENOMEM, "allocating path for watch");
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return ENOMEM;
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}
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strcpy(state, path);
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strcat(state, "/");
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strcat(state, path2);
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err = xenbus_watch_path(dev, state, watch, callback);
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if (err) {
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free(state, M_DEVBUF);
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}
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return err;
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}
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int
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xenbus_switch_state(struct xenbus_device *dev,
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struct xenbus_transaction *xbt,
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XenbusState state)
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{
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/* We check whether the state is currently set to the given value, and
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if not, then the state is set. We don't want to unconditionally
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write the given state, because we don't want to fire watches
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unnecessarily. Furthermore, if the node has gone, we don't write
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to it, as the device will be tearing down, and we don't want to
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resurrect that directory.
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*/
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u_long current_state;
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int err = xenbus_read_ul(xbt, dev->xbusd_path, "state",
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¤t_state, 10);
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if (err)
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return 0;
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if ((XenbusState)current_state == state)
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return 0;
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err = xenbus_printf(xbt, dev->xbusd_path, "state", "%d", state);
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if (err) {
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xenbus_dev_fatal(dev, err, "writing new state");
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return err;
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}
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return 0;
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}
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/**
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* Return the path to the error node for the given device, or NULL on failure.
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* If the value returned is non-NULL, then it is the caller's to kfree.
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*/
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static char *
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error_path(struct xenbus_device *dev)
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{
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char *path_buffer = malloc(strlen("error/") + strlen(dev->xbusd_path) +
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1, M_DEVBUF, M_NOWAIT);
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if (path_buffer == NULL) {
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return NULL;
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}
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strcpy(path_buffer, "error/");
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strcpy(path_buffer + strlen("error/"), dev->xbusd_path);
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return path_buffer;
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}
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static void
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_dev_error(struct xenbus_device *dev, int err, const char *fmt,
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va_list ap)
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{
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int ret;
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unsigned int len;
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char *printf_buffer = NULL, *path_buffer = NULL;
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#define PRINTF_BUFFER_SIZE 4096
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printf_buffer = malloc(PRINTF_BUFFER_SIZE, M_DEVBUF, M_NOWAIT);
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if (printf_buffer == NULL)
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goto fail;
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len = snprintf(printf_buffer, PRINTF_BUFFER_SIZE, "%i ", -err);
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ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap);
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KASSERT(len + ret < PRINTF_BUFFER_SIZE);
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dev->xbusd_has_error = 1;
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path_buffer = error_path(dev);
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if (path_buffer == NULL) {
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printk("xenbus: failed to write error node for %s (%s)\n",
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dev->xbusd_path, printf_buffer);
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goto fail;
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}
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if (xenbus_write(NULL, path_buffer, "error", printf_buffer) != 0) {
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printk("xenbus: failed to write error node for %s (%s)\n",
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dev->xbusd_path, printf_buffer);
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goto fail;
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}
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fail:
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if (printf_buffer)
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free(printf_buffer, M_DEVBUF);
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if (path_buffer)
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free(path_buffer, M_DEVBUF);
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}
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void
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xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt,
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...)
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{
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va_list ap;
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va_start(ap, fmt);
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_dev_error(dev, err, fmt, ap);
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va_end(ap);
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}
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void
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xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt,
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...)
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{
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va_list ap;
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va_start(ap, fmt);
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_dev_error(dev, err, fmt, ap);
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va_end(ap);
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xenbus_switch_state(dev, NULL, XenbusStateClosing);
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}
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int
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xenbus_grant_ring(struct xenbus_device *dev, paddr_t ring_pa,
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grant_ref_t *entryp)
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{
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int err = xengnt_grant_access(dev->xbusd_otherend_id, ring_pa,
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0, entryp);
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if (err != 0)
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xenbus_dev_fatal(dev, err, "granting access to ring page");
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return err;
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}
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int
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xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
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{
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evtchn_op_t op = {
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.cmd = EVTCHNOP_alloc_unbound,
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.u.alloc_unbound = {
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.dom = DOMID_SELF,
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.remote_dom = dev->xbusd_otherend_id,
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.port = 0
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}
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};
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int err = HYPERVISOR_event_channel_op(&op);
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if (err)
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xenbus_dev_fatal(dev, err, "allocating event channel");
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else
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*port = op.u.alloc_unbound.port;
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return err;
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}
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XenbusState
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xenbus_read_driver_state(const char *path)
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{
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u_long result;
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int err = xenbus_read_ul(NULL, path, "state", &result, 10);
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if (err)
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result = XenbusStateClosed;
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return result;
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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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