| 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 | |
| 58 | static int xenbus_dev_read(void *); |
| 59 | static int xenbus_dev_write(void *); |
| 60 | static int xenbus_dev_open(void *); |
| 61 | static int xenbus_dev_close(void *); |
| 62 | static int xsd_port_read(void *); |
| 63 | |
| 64 | struct 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) |
| 71 | static 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) |
| 79 | static const struct kernfs_fileop xsd_port_fileops[] = { |
| 80 | { .kf_fileop = KERNFS_FILEOP_READ, .kf_vop = xsd_port_read }, |
| 81 | }; |
| 82 | |
| 83 | void |
| 84 | xenbus_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 | |
| 104 | struct 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 | |
| 122 | static int |
| 123 | xenbus_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 | |
| 158 | end: |
| 159 | splx(s); |
| 160 | return err; |
| 161 | } |
| 162 | |
| 163 | static void |
| 164 | queue_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 | |
| 177 | static int |
| 178 | xenbus_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 | |
| 261 | static int |
| 262 | xenbus_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 | |
| 288 | static int |
| 289 | xenbus_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 | |
| 316 | static int |
| 317 | xsd_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 | |