1/* $NetBSD: xenbus_dev.c,v 1.10 2016/07/07 06:55:40 msaitoh Exp $ */
2/*
3 * xenbus_dev.c
4 *
5 * Driver giving user-space access to the kernel's xenbus connection
6 * to xenstore.
7 *
8 * Copyright (c) 2005, Christian Limpach
9 * Copyright (c) 2005, Rusty Russell, IBM Corporation
10 *
11 * This file may be distributed separately from the Linux kernel, or
12 * incorporated into other software packages, subject to the following license:
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
30 * IN THE SOFTWARE.
31 */
32
33#include <sys/cdefs.h>
34__KERNEL_RCSID(0, "$NetBSD: xenbus_dev.c,v 1.10 2016/07/07 06:55:40 msaitoh Exp $");
35
36#include "opt_xen.h"
37
38#include <sys/types.h>
39#include <sys/null.h>
40#include <sys/errno.h>
41#include <sys/malloc.h>
42#include <sys/param.h>
43#include <sys/proc.h>
44#include <sys/systm.h>
45#include <sys/dirent.h>
46#include <sys/stat.h>
47#include <sys/tree.h>
48#include <sys/vnode.h>
49#include <miscfs/specfs/specdev.h>
50#include <miscfs/kernfs/kernfs.h>
51
52#include <xen/kernfs_machdep.h>
53
54#include <xen/hypervisor.h>
55#include <xen/xenbus.h>
56#include "xenbus_comms.h"
57
58static int xenbus_dev_read(void *);
59static int xenbus_dev_write(void *);
60static int xenbus_dev_open(void *);
61static int xenbus_dev_close(void *);
62static int xsd_port_read(void *);
63
64struct xenbus_dev_transaction {
65 SLIST_ENTRY(xenbus_dev_transaction) trans_next;
66 struct xenbus_transaction *handle;
67};
68
69#define DIR_MODE (S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
70#define PRIVCMD_MODE (S_IRUSR | S_IWUSR)
71static const struct kernfs_fileop xenbus_fileops[] = {
72 { .kf_fileop = KERNFS_FILEOP_OPEN, .kf_vop = xenbus_dev_open },
73 { .kf_fileop = KERNFS_FILEOP_CLOSE, .kf_vop = xenbus_dev_close },
74 { .kf_fileop = KERNFS_FILEOP_READ, .kf_vop = xenbus_dev_read },
75 { .kf_fileop = KERNFS_FILEOP_WRITE, .kf_vop = xenbus_dev_write },
76};
77
78#define XSD_MODE (S_IRUSR)
79static const struct kernfs_fileop xsd_port_fileops[] = {
80 { .kf_fileop = KERNFS_FILEOP_READ, .kf_vop = xsd_port_read },
81};
82
83void
84xenbus_kernfs_init(void)
85{
86 kernfs_entry_t *dkt;
87 kfstype kfst;
88
89 kfst = KERNFS_ALLOCTYPE(xenbus_fileops);
90 KERNFS_ALLOCENTRY(dkt, M_TEMP, M_WAITOK);
91 KERNFS_INITENTRY(dkt, DT_REG, "xenbus", NULL, kfst, VREG,
92 PRIVCMD_MODE);
93 kernfs_addentry(kernxen_pkt, dkt);
94
95 if (xendomain_is_dom0()) {
96 kfst = KERNFS_ALLOCTYPE(xsd_port_fileops);
97 KERNFS_ALLOCENTRY(dkt, M_TEMP, M_WAITOK);
98 KERNFS_INITENTRY(dkt, DT_REG, "xsd_port", NULL,
99 kfst, VREG, XSD_MODE);
100 kernfs_addentry(kernxen_pkt, dkt);
101 }
102}
103
104struct xenbus_dev_data {
105#define BUFFER_SIZE (PAGE_SIZE)
106#define MASK_READ_IDX(idx) ((idx)&(BUFFER_SIZE-1))
107 /* In-progress transaction. */
108 SLIST_HEAD(, xenbus_dev_transaction) transactions;
109
110 /* Partial request. */
111 unsigned int len;
112 union {
113 struct xsd_sockmsg msg;
114 char buffer[BUFFER_SIZE];
115 } u;
116
117 /* Response queue. */
118 char read_buffer[BUFFER_SIZE];
119 unsigned int read_cons, read_prod;
120};
121
122static int
123xenbus_dev_read(void *v)
124{
125 struct vop_read_args /* {
126 struct vnode *a_vp;
127 struct uio *a_uio;
128 int a_ioflag;
129 struct ucred *a_cred;
130 } */ *ap = v;
131 struct kernfs_node *kfs = VTOKERN(ap->a_vp);
132 struct uio *uio = ap->a_uio;
133 struct xenbus_dev_data *u = kfs->kfs_v;
134 int err;
135 off_t offset;
136 int s = spltty();
137
138 while (u->read_prod == u->read_cons) {
139 err = tsleep(u, PRIBIO | PCATCH, "xbrd", 0);
140 if (err)
141 goto end;
142 }
143 offset = uio->uio_offset;
144
145 if (u->read_cons > u->read_prod) {
146 err = uiomove(&u->read_buffer[MASK_READ_IDX(u->read_cons)],
147 0U - u->read_cons, uio);
148 if (err)
149 goto end;
150 u->read_cons += (uio->uio_offset - offset);
151 offset = uio->uio_offset;
152 }
153 err = uiomove(&u->read_buffer[MASK_READ_IDX(u->read_cons)],
154 u->read_prod - u->read_cons, uio);
155 if (err == 0)
156 u->read_cons += (uio->uio_offset - offset);
157
158end:
159 splx(s);
160 return err;
161}
162
163static void
164queue_reply(struct xenbus_dev_data *u,
165 char *data, unsigned int len)
166{
167 int i;
168
169 for (i = 0; i < len; i++, u->read_prod++)
170 u->read_buffer[MASK_READ_IDX(u->read_prod)] = data[i];
171
172 KASSERT((u->read_prod - u->read_cons) <= sizeof(u->read_buffer));
173
174 wakeup(&u);
175}
176
177static int
178xenbus_dev_write(void *v)
179{
180 struct vop_write_args /* {
181 struct vnode *a_vp;
182 struct uio *a_uio;
183 int a_ioflag;
184 struct ucred *a_cred;
185 } */ *ap = v;
186 struct kernfs_node *kfs = VTOKERN(ap->a_vp);
187 struct uio *uio = ap->a_uio;
188
189 struct xenbus_dev_data *u = kfs->kfs_v;
190 struct xenbus_dev_transaction *trans;
191 void *reply;
192 int err;
193 size_t size;
194
195 if (uio->uio_offset < 0)
196 return EINVAL;
197 size = uio->uio_resid;
198
199 if ((size + u->len) > sizeof(u->u.buffer))
200 return EINVAL;
201
202 err = uiomove(u->u.buffer + u->len, sizeof(u->u.buffer) - u->len, uio);
203 if (err)
204 return err;
205
206 u->len += size;
207 if (u->len < (sizeof(u->u.msg) + u->u.msg.len))
208 return 0;
209
210 switch (u->u.msg.type) {
211 case XS_TRANSACTION_START:
212 case XS_TRANSACTION_END:
213 case XS_DIRECTORY:
214 case XS_READ:
215 case XS_GET_PERMS:
216 case XS_RELEASE:
217 case XS_GET_DOMAIN_PATH:
218 case XS_WRITE:
219 case XS_MKDIR:
220 case XS_RM:
221 case XS_SET_PERMS:
222 err = xenbus_dev_request_and_reply(&u->u.msg, &reply);
223 if (err == 0) {
224 if (u->u.msg.type == XS_TRANSACTION_START) {
225 trans = malloc(sizeof(*trans), M_DEVBUF,
226 M_WAITOK);
227 trans->handle = (struct xenbus_transaction *)
228 strtoul(reply, NULL, 0);
229 SLIST_INSERT_HEAD(&u->transactions,
230 trans, trans_next);
231 } else if (u->u.msg.type == XS_TRANSACTION_END) {
232 SLIST_FOREACH(trans, &u->transactions,
233 trans_next) {
234 if ((unsigned long)trans->handle ==
235 (unsigned long)u->u.msg.tx_id)
236 break;
237 }
238 KASSERT(trans != NULL);
239 SLIST_REMOVE(&u->transactions, trans,
240 xenbus_dev_transaction, trans_next);
241 free(trans, M_DEVBUF);
242 }
243 queue_reply(u, (char *)&u->u.msg, sizeof(u->u.msg));
244 queue_reply(u, (char *)reply, u->u.msg.len);
245 free(reply, M_DEVBUF);
246 }
247 break;
248
249 default:
250 err = EINVAL;
251 break;
252 }
253
254 if (err == 0) {
255 u->len = 0;
256 }
257
258 return err;
259}
260
261static int
262xenbus_dev_open(void *v)
263{
264 struct vop_open_args /* {
265 struct vnode *a_vp;
266 int a_mode;
267 struct ucred *a_cred;
268 } */ *ap = v;
269 struct kernfs_node *kfs = VTOKERN(ap->a_vp);
270
271 struct xenbus_dev_data *u;
272
273 if (xen_start_info.store_evtchn == 0)
274 return ENOENT;
275
276 u = malloc(sizeof(*u), M_DEVBUF, M_WAITOK);
277 if (u == NULL)
278 return ENOMEM;
279
280 memset(u, 0, sizeof(*u));
281 SLIST_INIT(&u->transactions);
282
283 kfs->kfs_v = u;
284
285 return 0;
286}
287
288static int
289xenbus_dev_close(void *v)
290{
291 struct vop_close_args /* {
292 struct vnode *a_vp;
293 int a_fflag;
294 struct ucred *a_cred;
295 } */ *ap = v;
296 struct kernfs_node *kfs = VTOKERN(ap->a_vp);
297
298 struct xenbus_dev_data *u = kfs->kfs_v;
299 struct xenbus_dev_transaction *trans;
300
301 while (!SLIST_EMPTY(&u->transactions)) {
302 trans = SLIST_FIRST(&u->transactions);
303 xenbus_transaction_end(trans->handle, 1);
304 SLIST_REMOVE_HEAD(&u->transactions, trans_next);
305 free(trans, M_DEVBUF);
306 }
307
308 free(u, M_DEVBUF);
309 kfs->kfs_v = NULL;
310
311 return 0;
312}
313
314#define LD_STRLEN 21 /* a 64bit integer needs 20 digits in base10 */
315
316static int
317xsd_port_read(void *v)
318{
319 struct vop_read_args /* {
320 struct vnode *a_vp;
321 struct uio *a_uio;
322 int a_ioflag;
323 struct ucred *a_cred;
324 } */ *ap = v;
325 struct uio *uio = ap->a_uio;
326 int off, error;
327 size_t len;
328 char strbuf[LD_STRLEN], *bf;
329
330 off = (int)uio->uio_offset;
331 if (off < 0)
332 return EINVAL;
333
334 len = snprintf(strbuf, sizeof(strbuf), "%ld\n",
335 (long)xen_start_info.store_evtchn);
336 if (off >= len) {
337 bf = strbuf;
338 len = 0;
339 } else {
340 bf = &strbuf[off];
341 len -= off;
342 }
343 error = uiomove(bf, len, uio);
344 return error;
345}
346
347/*
348 * Local variables:
349 * c-file-style: "linux"
350 * indent-tabs-mode: t
351 * c-indent-level: 8
352 * c-basic-offset: 8
353 * tab-width: 8
354 * End:
355 */
356