| 1 | /* |
| 2 | * QEMU Xen emulation: Shared/overlay pages support |
| 3 | * |
| 4 | * Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| 5 | * |
| 6 | * Authors: David Woodhouse <dwmw2@infradead.org> |
| 7 | * |
| 8 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 9 | * See the COPYING file in the top-level directory. |
| 10 | */ |
| 11 | |
| 12 | #include "qemu/osdep.h" |
| 13 | |
| 14 | #include "qemu/host-utils.h" |
| 15 | #include "qemu/module.h" |
| 16 | #include "qemu/main-loop.h" |
| 17 | #include "qemu/cutils.h" |
| 18 | #include "qemu/error-report.h" |
| 19 | #include "qapi/error.h" |
| 20 | #include "qom/object.h" |
| 21 | #include "migration/vmstate.h" |
| 22 | |
| 23 | #include "hw/core/sysbus.h" |
| 24 | #include "hw/xen/xen.h" |
| 25 | #include "hw/xen/xen_backend_ops.h" |
| 26 | #include "xen_overlay.h" |
| 27 | #include "xen_evtchn.h" |
| 28 | #include "xen_primary_console.h" |
| 29 | #include "xen_xenstore.h" |
| 30 | |
| 31 | #include "system/kvm.h" |
| 32 | #include "system/kvm_xen.h" |
| 33 | |
| 34 | #include "trace.h" |
| 35 | |
| 36 | #include "xenstore_impl.h" |
| 37 | |
| 38 | #include "hw/xen/interface/io/xs_wire.h" |
| 39 | #include "hw/xen/interface/event_channel.h" |
| 40 | #include "hw/xen/interface/grant_table.h" |
| 41 | |
| 42 | #define TYPE_XEN_XENSTORE "xen-xenstore" |
| 43 | OBJECT_DECLARE_SIMPLE_TYPE(XenXenstoreState, XEN_XENSTORE) |
| 44 | |
| 45 | #define ENTRIES_PER_FRAME_V1 (XEN_PAGE_SIZE / sizeof(grant_entry_v1_t)) |
| 46 | #define ENTRIES_PER_FRAME_V2 (XEN_PAGE_SIZE / sizeof(grant_entry_v2_t)) |
| 47 | |
| 48 | #define XENSTORE_HEADER_SIZE ((unsigned int)sizeof(struct xsd_sockmsg)) |
| 49 | |
| 50 | struct XenXenstoreState { |
| 51 | /*< private >*/ |
| 52 | SysBusDevice busdev; |
| 53 | /*< public >*/ |
| 54 | |
| 55 | XenstoreImplState *impl; |
| 56 | GList *watch_events; /* for the guest */ |
| 57 | |
| 58 | MemoryRegion xenstore_page; |
| 59 | struct xenstore_domain_interface *xs; |
| 60 | uint8_t req_data[XENSTORE_HEADER_SIZE + XENSTORE_PAYLOAD_MAX]; |
| 61 | uint8_t rsp_data[XENSTORE_HEADER_SIZE + XENSTORE_PAYLOAD_MAX]; |
| 62 | uint32_t req_offset; |
| 63 | uint32_t rsp_offset; |
| 64 | bool rsp_pending; |
| 65 | bool fatal_error; |
| 66 | |
| 67 | evtchn_port_t guest_port; |
| 68 | evtchn_port_t be_port; |
| 69 | struct xenevtchn_handle *eh; |
| 70 | |
| 71 | uint8_t *impl_state; |
| 72 | uint32_t impl_state_size; |
| 73 | |
| 74 | struct xengntdev_handle *gt; |
| 75 | void *granted_xs; |
| 76 | }; |
| 77 | |
| 78 | struct XenXenstoreState *xen_xenstore_singleton; |
| 79 | |
| 80 | static void xen_xenstore_event(void *opaque); |
| 81 | static void fire_watch_cb(void *opaque, const char *path, const char *token); |
| 82 | |
| 83 | static struct xenstore_backend_ops emu_xenstore_backend_ops; |
| 84 | |
| 85 | static void G_GNUC_PRINTF (4, 5) relpath_printf(XenXenstoreState *s, |
| 86 | GList *perms, |
| 87 | const char *relpath, |
| 88 | const char *fmt, ...) |
| 89 | { |
| 90 | gchar *abspath; |
| 91 | gchar *value; |
| 92 | va_list args; |
| 93 | GByteArray *data; |
| 94 | int err; |
| 95 | |
| 96 | abspath = g_strdup_printf("/local/domain/%u/%s", xen_domid, relpath); |
| 97 | va_start(args, fmt); |
| 98 | value = g_strdup_vprintf(fmt, args); |
| 99 | va_end(args); |
| 100 | |
| 101 | data = g_byte_array_new_take((void *)value, strlen(value)); |
| 102 | |
| 103 | err = xs_impl_write(s->impl, DOMID_QEMU, XBT_NULL, abspath, data); |
| 104 | assert(!err); |
| 105 | |
| 106 | g_byte_array_unref(data); |
| 107 | |
| 108 | err = xs_impl_set_perms(s->impl, DOMID_QEMU, XBT_NULL, abspath, perms); |
| 109 | assert(!err); |
| 110 | |
| 111 | g_free(abspath); |
| 112 | } |
| 113 | |
| 114 | static void xen_xenstore_realize(DeviceState *dev, Error **errp) |
| 115 | { |
| 116 | XenXenstoreState *s = XEN_XENSTORE(dev); |
| 117 | GList *perms; |
| 118 | |
| 119 | if (xen_mode != XEN_EMULATE) { |
| 120 | error_setg(errp, "Xen xenstore support is for Xen emulation"); |
| 121 | return; |
| 122 | } |
| 123 | memory_region_init_ram(&s->xenstore_page, OBJECT(dev), "xen:xenstore_page", |
| 124 | XEN_PAGE_SIZE, &error_abort); |
| 125 | memory_region_set_enabled(&s->xenstore_page, true); |
| 126 | s->xs = memory_region_get_ram_ptr(&s->xenstore_page); |
| 127 | memset(s->xs, 0, XEN_PAGE_SIZE); |
| 128 | |
| 129 | /* We can't map it this early as KVM isn't ready */ |
| 130 | xen_xenstore_singleton = s; |
| 131 | |
| 132 | s->eh = xen_be_evtchn_open(); |
| 133 | if (!s->eh) { |
| 134 | error_setg(errp, "Xenstore evtchn port init failed"); |
| 135 | return; |
| 136 | } |
| 137 | aio_set_fd_handler(qemu_get_aio_context(), xen_be_evtchn_fd(s->eh), |
| 138 | xen_xenstore_event, NULL, NULL, NULL, s); |
| 139 | |
| 140 | s->impl = xs_impl_create(xen_domid); |
| 141 | |
| 142 | /* Populate the default nodes */ |
| 143 | |
| 144 | /* Nodes owned by 'dom0' but readable by the guest */ |
| 145 | perms = g_list_append(NULL, xs_perm_as_string(XS_PERM_NONE, DOMID_QEMU)); |
| 146 | perms = g_list_append(perms, xs_perm_as_string(XS_PERM_READ, xen_domid)); |
| 147 | |
| 148 | relpath_printf(s, perms, "", "%s", ""); |
| 149 | |
| 150 | relpath_printf(s, perms, "domid", "%u", xen_domid); |
| 151 | |
| 152 | relpath_printf(s, perms, "control/platform-feature-xs_reset_watches", "%u", 1); |
| 153 | relpath_printf(s, perms, "control/platform-feature-multiprocessor-suspend", "%u", 1); |
| 154 | |
| 155 | relpath_printf(s, perms, "platform/acpi", "%u", 1); |
| 156 | relpath_printf(s, perms, "platform/acpi_s3", "%u", 1); |
| 157 | relpath_printf(s, perms, "platform/acpi_s4", "%u", 1); |
| 158 | relpath_printf(s, perms, "platform/acpi_laptop_slate", "%u", 0); |
| 159 | |
| 160 | g_list_free_full(perms, g_free); |
| 161 | |
| 162 | /* Nodes owned by the guest */ |
| 163 | perms = g_list_append(NULL, xs_perm_as_string(XS_PERM_NONE, xen_domid)); |
| 164 | |
| 165 | relpath_printf(s, perms, "attr", "%s", ""); |
| 166 | |
| 167 | relpath_printf(s, perms, "control/shutdown", "%s", ""); |
| 168 | relpath_printf(s, perms, "control/feature-poweroff", "%u", 1); |
| 169 | relpath_printf(s, perms, "control/feature-reboot", "%u", 1); |
| 170 | relpath_printf(s, perms, "control/feature-suspend", "%u", 1); |
| 171 | relpath_printf(s, perms, "control/feature-s3", "%u", 1); |
| 172 | relpath_printf(s, perms, "control/feature-s4", "%u", 1); |
| 173 | |
| 174 | relpath_printf(s, perms, "data", "%s", ""); |
| 175 | relpath_printf(s, perms, "device", "%s", ""); |
| 176 | relpath_printf(s, perms, "drivers", "%s", ""); |
| 177 | relpath_printf(s, perms, "error", "%s", ""); |
| 178 | relpath_printf(s, perms, "feature", "%s", ""); |
| 179 | |
| 180 | g_list_free_full(perms, g_free); |
| 181 | |
| 182 | xen_xenstore_ops = &emu_xenstore_backend_ops; |
| 183 | } |
| 184 | |
| 185 | static bool xen_xenstore_is_needed(void *opaque) |
| 186 | { |
| 187 | return xen_mode == XEN_EMULATE; |
| 188 | } |
| 189 | |
| 190 | static int xen_xenstore_pre_save(void *opaque) |
| 191 | { |
| 192 | XenXenstoreState *s = opaque; |
| 193 | GByteArray *save; |
| 194 | |
| 195 | if (s->eh) { |
| 196 | s->guest_port = xen_be_evtchn_get_guest_port(s->eh); |
| 197 | } |
| 198 | |
| 199 | g_free(s->impl_state); |
| 200 | save = xs_impl_serialize(s->impl); |
| 201 | s->impl_state = save->data; |
| 202 | s->impl_state_size = save->len; |
| 203 | g_byte_array_free(save, false); |
| 204 | |
| 205 | return 0; |
| 206 | } |
| 207 | |
| 208 | static int xen_xenstore_post_load(void *opaque, int ver) |
| 209 | { |
| 210 | XenXenstoreState *s = opaque; |
| 211 | GByteArray *save; |
| 212 | |
| 213 | /* |
| 214 | * As qemu/dom0, rebind to the guest's port. The Windows drivers may |
| 215 | * unbind the XenStore evtchn and rebind to it, having obtained the |
| 216 | * "remote" port through EVTCHNOP_status. In the case that migration |
| 217 | * occurs while it's unbound, the "remote" port needs to be the same |
| 218 | * as before so that the guest can find it, but should remain unbound. |
| 219 | */ |
| 220 | if (s->guest_port) { |
| 221 | int be_port = xen_be_evtchn_bind_interdomain(s->eh, xen_domid, |
| 222 | s->guest_port); |
| 223 | if (be_port < 0) { |
| 224 | return be_port; |
| 225 | } |
| 226 | s->be_port = be_port; |
| 227 | } |
| 228 | |
| 229 | save = g_byte_array_new_take(s->impl_state, s->impl_state_size); |
| 230 | s->impl_state = NULL; |
| 231 | s->impl_state_size = 0; |
| 232 | |
| 233 | return xs_impl_deserialize(s->impl, save, xen_domid, fire_watch_cb, s); |
| 234 | } |
| 235 | |
| 236 | static const VMStateDescription xen_xenstore_vmstate = { |
| 237 | .name = "xen_xenstore", |
| 238 | .unmigratable = 1, /* The PV back ends don't migrate yet */ |
| 239 | .version_id = 1, |
| 240 | .minimum_version_id = 1, |
| 241 | .needed = xen_xenstore_is_needed, |
| 242 | .pre_save = xen_xenstore_pre_save, |
| 243 | .post_load = xen_xenstore_post_load, |
| 244 | .fields = (const VMStateField[]) { |
| 245 | VMSTATE_UINT8_ARRAY(req_data, XenXenstoreState, |
| 246 | sizeof_field(XenXenstoreState, req_data)), |
| 247 | VMSTATE_UINT8_ARRAY(rsp_data, XenXenstoreState, |
| 248 | sizeof_field(XenXenstoreState, rsp_data)), |
| 249 | VMSTATE_UINT32(req_offset, XenXenstoreState), |
| 250 | VMSTATE_UINT32(rsp_offset, XenXenstoreState), |
| 251 | VMSTATE_BOOL(rsp_pending, XenXenstoreState), |
| 252 | VMSTATE_UINT32(guest_port, XenXenstoreState), |
| 253 | VMSTATE_BOOL(fatal_error, XenXenstoreState), |
| 254 | VMSTATE_UINT32(impl_state_size, XenXenstoreState), |
| 255 | VMSTATE_VARRAY_UINT32_ALLOC(impl_state, XenXenstoreState, |
| 256 | impl_state_size, 0, |
| 257 | vmstate_info_uint8, uint8_t), |
| 258 | VMSTATE_END_OF_LIST() |
| 259 | } |
| 260 | }; |
| 261 | |
| 262 | static void xen_xenstore_class_init(ObjectClass *klass, const void *data) |
| 263 | { |
| 264 | DeviceClass *dc = DEVICE_CLASS(klass); |
| 265 | |
| 266 | dc->realize = xen_xenstore_realize; |
| 267 | dc->vmsd = &xen_xenstore_vmstate; |
| 268 | } |
| 269 | |
| 270 | static const TypeInfo xen_xenstore_info = { |
| 271 | .name = TYPE_XEN_XENSTORE, |
| 272 | .parent = TYPE_SYS_BUS_DEVICE, |
| 273 | .instance_size = sizeof(XenXenstoreState), |
| 274 | .class_init = xen_xenstore_class_init, |
| 275 | }; |
| 276 | |
| 277 | void xen_xenstore_create(void) |
| 278 | { |
| 279 | DeviceState *dev = sysbus_create_simple(TYPE_XEN_XENSTORE, -1, NULL); |
| 280 | |
| 281 | xen_xenstore_singleton = XEN_XENSTORE(dev); |
| 282 | |
| 283 | /* |
| 284 | * Defer the init (xen_xenstore_reset()) until KVM is set up and the |
| 285 | * overlay page can be mapped. |
| 286 | */ |
| 287 | } |
| 288 | |
| 289 | static void xen_xenstore_register_types(void) |
| 290 | { |
| 291 | type_register_static(&xen_xenstore_info); |
| 292 | } |
| 293 | |
| 294 | type_init(xen_xenstore_register_types) |
| 295 | |
| 296 | uint16_t xen_xenstore_get_port(void) |
| 297 | { |
| 298 | XenXenstoreState *s = xen_xenstore_singleton; |
| 299 | if (!s) { |
| 300 | return 0; |
| 301 | } |
| 302 | return s->guest_port; |
| 303 | } |
| 304 | |
| 305 | static bool req_pending(XenXenstoreState *s) |
| 306 | { |
| 307 | struct xsd_sockmsg *req = (struct xsd_sockmsg *)s->req_data; |
| 308 | |
| 309 | return s->req_offset == XENSTORE_HEADER_SIZE + req->len; |
| 310 | } |
| 311 | |
| 312 | static void reset_req(XenXenstoreState *s) |
| 313 | { |
| 314 | memset(s->req_data, 0, sizeof(s->req_data)); |
| 315 | s->req_offset = 0; |
| 316 | } |
| 317 | |
| 318 | static void reset_rsp(XenXenstoreState *s) |
| 319 | { |
| 320 | s->rsp_pending = false; |
| 321 | |
| 322 | memset(s->rsp_data, 0, sizeof(s->rsp_data)); |
| 323 | s->rsp_offset = 0; |
| 324 | } |
| 325 | |
| 326 | static void xs_error(XenXenstoreState *s, unsigned int id, |
| 327 | xs_transaction_t tx_id, int errnum) |
| 328 | { |
| 329 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 330 | const char *errstr = NULL; |
| 331 | |
| 332 | for (unsigned int i = 0; i < ARRAY_SIZE(xsd_errors); i++) { |
| 333 | const struct xsd_errors *xsd_error = &xsd_errors[i]; |
| 334 | |
| 335 | if (xsd_error->errnum == errnum) { |
| 336 | errstr = xsd_error->errstring; |
| 337 | break; |
| 338 | } |
| 339 | } |
| 340 | assert(errstr); |
| 341 | |
| 342 | trace_xenstore_error(id, tx_id, errstr); |
| 343 | |
| 344 | rsp->type = XS_ERROR; |
| 345 | rsp->req_id = id; |
| 346 | rsp->tx_id = tx_id; |
| 347 | rsp->len = (uint32_t)strlen(errstr) + 1; |
| 348 | |
| 349 | memcpy(&rsp[1], errstr, rsp->len); |
| 350 | } |
| 351 | |
| 352 | static void xs_ok(XenXenstoreState *s, unsigned int type, unsigned int req_id, |
| 353 | xs_transaction_t tx_id) |
| 354 | { |
| 355 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 356 | const char *okstr = "OK"; |
| 357 | |
| 358 | rsp->type = type; |
| 359 | rsp->req_id = req_id; |
| 360 | rsp->tx_id = tx_id; |
| 361 | rsp->len = (uint32_t)strlen(okstr) + 1; |
| 362 | |
| 363 | memcpy(&rsp[1], okstr, rsp->len); |
| 364 | } |
| 365 | |
| 366 | /* |
| 367 | * The correct request and response formats are documented in xen.git: |
| 368 | * docs/misc/xenstore.txt. A summary is given below for convenience. |
| 369 | * The '|' symbol represents a NUL character. |
| 370 | * |
| 371 | * ---------- Database read, write and permissions operations ---------- |
| 372 | * |
| 373 | * READ <path>| <value|> |
| 374 | * WRITE <path>|<value|> |
| 375 | * Store and read the octet string <value> at <path>. |
| 376 | * WRITE creates any missing parent paths, with empty values. |
| 377 | * |
| 378 | * MKDIR <path>| |
| 379 | * Ensures that the <path> exists, by necessary by creating |
| 380 | * it and any missing parents with empty values. If <path> |
| 381 | * or any parent already exists, its value is left unchanged. |
| 382 | * |
| 383 | * RM <path>| |
| 384 | * Ensures that the <path> does not exist, by deleting |
| 385 | * it and all of its children. It is not an error if <path> does |
| 386 | * not exist, but it _is_ an error if <path>'s immediate parent |
| 387 | * does not exist either. |
| 388 | * |
| 389 | * DIRECTORY <path>| <child-leaf-name>|* |
| 390 | * Gives a list of the immediate children of <path>, as only the |
| 391 | * leafnames. The resulting children are each named |
| 392 | * <path>/<child-leaf-name>. |
| 393 | * |
| 394 | * DIRECTORY_PART <path>|<offset> <gencnt>|<child-leaf-name>|* |
| 395 | * Same as DIRECTORY, but to be used for children lists longer than |
| 396 | * XENSTORE_PAYLOAD_MAX. Input are <path> and the byte offset into |
| 397 | * the list of children to return. Return values are the generation |
| 398 | * count <gencnt> of the node (to be used to ensure the node hasn't |
| 399 | * changed between two reads: <gencnt> being the same for multiple |
| 400 | * reads guarantees the node hasn't changed) and the list of children |
| 401 | * starting at the specified <offset> of the complete list. |
| 402 | * |
| 403 | * GET_PERMS <path>| <perm-as-string>|+ |
| 404 | * SET_PERMS <path>|<perm-as-string>|+? |
| 405 | * <perm-as-string> is one of the following |
| 406 | * w<domid> write only |
| 407 | * r<domid> read only |
| 408 | * b<domid> both read and write |
| 409 | * n<domid> no access |
| 410 | * See https://wiki.xen.org/wiki/XenBus section |
| 411 | * `Permissions' for details of the permissions system. |
| 412 | * It is possible to set permissions for the special watch paths |
| 413 | * "@introduceDomain" and "@releaseDomain" to enable receiving those |
| 414 | * watches in unprivileged domains. |
| 415 | * |
| 416 | * ---------- Watches ---------- |
| 417 | * |
| 418 | * WATCH <wpath>|<token>|? |
| 419 | * Adds a watch. |
| 420 | * |
| 421 | * When a <path> is modified (including path creation, removal, |
| 422 | * contents change or permissions change) this generates an event |
| 423 | * on the changed <path>. Changes made in transactions cause an |
| 424 | * event only if and when committed. Each occurring event is |
| 425 | * matched against all the watches currently set up, and each |
| 426 | * matching watch results in a WATCH_EVENT message (see below). |
| 427 | * |
| 428 | * The event's path matches the watch's <wpath> if it is an child |
| 429 | * of <wpath>. |
| 430 | * |
| 431 | * <wpath> can be a <path> to watch or @<wspecial>. In the |
| 432 | * latter case <wspecial> may have any syntax but it matches |
| 433 | * (according to the rules above) only the following special |
| 434 | * events which are invented by xenstored: |
| 435 | * @introduceDomain occurs on INTRODUCE |
| 436 | * @releaseDomain occurs on any domain crash or |
| 437 | * shutdown, and also on RELEASE |
| 438 | * and domain destruction |
| 439 | * <wspecial> events are sent to privileged callers or explicitly |
| 440 | * via SET_PERMS enabled domains only. |
| 441 | * |
| 442 | * When a watch is first set up it is triggered once straight |
| 443 | * away, with <path> equal to <wpath>. Watches may be triggered |
| 444 | * spuriously. The tx_id in a WATCH request is ignored. |
| 445 | * |
| 446 | * Watches are supposed to be restricted by the permissions |
| 447 | * system but in practice the implementation is imperfect. |
| 448 | * Applications should not rely on being sent a notification for |
| 449 | * paths that they cannot read; however, an application may rely |
| 450 | * on being sent a watch when a path which it _is_ able to read |
| 451 | * is deleted even if that leaves only a nonexistent unreadable |
| 452 | * parent. A notification may omitted if a node's permissions |
| 453 | * are changed so as to make it unreadable, in which case future |
| 454 | * notifications may be suppressed (and if the node is later made |
| 455 | * readable, some notifications may have been lost). |
| 456 | * |
| 457 | * WATCH_EVENT <epath>|<token>| |
| 458 | * Unsolicited `reply' generated for matching modification events |
| 459 | * as described above. req_id and tx_id are both 0. |
| 460 | * |
| 461 | * <epath> is the event's path, ie the actual path that was |
| 462 | * modified; however if the event was the recursive removal of an |
| 463 | * parent of <wpath>, <epath> is just |
| 464 | * <wpath> (rather than the actual path which was removed). So |
| 465 | * <epath> is a child of <wpath>, regardless. |
| 466 | * |
| 467 | * Iff <wpath> for the watch was specified as a relative pathname, |
| 468 | * the <epath> path will also be relative (with the same base, |
| 469 | * obviously). |
| 470 | * |
| 471 | * UNWATCH <wpath>|<token>|? |
| 472 | * |
| 473 | * RESET_WATCHES | |
| 474 | * Reset all watches and transactions of the caller. |
| 475 | * |
| 476 | * ---------- Transactions ---------- |
| 477 | * |
| 478 | * TRANSACTION_START | <transid>| |
| 479 | * <transid> is an opaque uint32_t allocated by xenstored |
| 480 | * represented as unsigned decimal. After this, transaction may |
| 481 | * be referenced by using <transid> (as 32-bit binary) in the |
| 482 | * tx_id request header field. When transaction is started whole |
| 483 | * db is copied; reads and writes happen on the copy. |
| 484 | * It is not legal to send non-0 tx_id in TRANSACTION_START. |
| 485 | * |
| 486 | * TRANSACTION_END T| |
| 487 | * TRANSACTION_END F| |
| 488 | * tx_id must refer to existing transaction. After this |
| 489 | * request the tx_id is no longer valid and may be reused by |
| 490 | * xenstore. If F, the transaction is discarded. If T, |
| 491 | * it is committed: if there were any other intervening writes |
| 492 | * then our END gets get EAGAIN. |
| 493 | * |
| 494 | * The plan is that in the future only intervening `conflicting' |
| 495 | * writes cause EAGAIN, meaning only writes or other commits |
| 496 | * which changed paths which were read or written in the |
| 497 | * transaction at hand. |
| 498 | * |
| 499 | */ |
| 500 | |
| 501 | static void xs_read(XenXenstoreState *s, unsigned int req_id, |
| 502 | xs_transaction_t tx_id, uint8_t *req_data, unsigned int len) |
| 503 | { |
| 504 | const char *path = (const char *)req_data; |
| 505 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 506 | uint8_t *rsp_data = (uint8_t *)&rsp[1]; |
| 507 | g_autoptr(GByteArray) data = g_byte_array_new(); |
| 508 | int err; |
| 509 | |
| 510 | if (len == 0 || req_data[len - 1] != '\0') { |
| 511 | xs_error(s, req_id, tx_id, EINVAL); |
| 512 | return; |
| 513 | } |
| 514 | |
| 515 | trace_xenstore_read(tx_id, path); |
| 516 | err = xs_impl_read(s->impl, xen_domid, tx_id, path, data); |
| 517 | if (err) { |
| 518 | xs_error(s, req_id, tx_id, err); |
| 519 | return; |
| 520 | } |
| 521 | |
| 522 | rsp->type = XS_READ; |
| 523 | rsp->req_id = req_id; |
| 524 | rsp->tx_id = tx_id; |
| 525 | rsp->len = 0; |
| 526 | |
| 527 | len = data->len; |
| 528 | if (len > XENSTORE_PAYLOAD_MAX) { |
| 529 | xs_error(s, req_id, tx_id, E2BIG); |
| 530 | return; |
| 531 | } |
| 532 | |
| 533 | if (!len) { |
| 534 | return; |
| 535 | } |
| 536 | |
| 537 | memcpy(&rsp_data[rsp->len], data->data, len); |
| 538 | rsp->len += len; |
| 539 | } |
| 540 | |
| 541 | static void xs_write(XenXenstoreState *s, unsigned int req_id, |
| 542 | xs_transaction_t tx_id, uint8_t *req_data, |
| 543 | unsigned int len) |
| 544 | { |
| 545 | g_autoptr(GByteArray) data = g_byte_array_new(); |
| 546 | const char *path; |
| 547 | int err; |
| 548 | |
| 549 | if (len == 0) { |
| 550 | xs_error(s, req_id, tx_id, EINVAL); |
| 551 | return; |
| 552 | } |
| 553 | |
| 554 | path = (const char *)req_data; |
| 555 | |
| 556 | while (len--) { |
| 557 | if (*req_data++ == '\0') { |
| 558 | break; |
| 559 | } |
| 560 | if (len == 0) { |
| 561 | xs_error(s, req_id, tx_id, EINVAL); |
| 562 | return; |
| 563 | } |
| 564 | } |
| 565 | |
| 566 | g_byte_array_append(data, req_data, len); |
| 567 | |
| 568 | trace_xenstore_write(tx_id, path); |
| 569 | err = xs_impl_write(s->impl, xen_domid, tx_id, path, data); |
| 570 | if (err) { |
| 571 | xs_error(s, req_id, tx_id, err); |
| 572 | return; |
| 573 | } |
| 574 | |
| 575 | xs_ok(s, XS_WRITE, req_id, tx_id); |
| 576 | } |
| 577 | |
| 578 | static void xs_mkdir(XenXenstoreState *s, unsigned int req_id, |
| 579 | xs_transaction_t tx_id, uint8_t *req_data, |
| 580 | unsigned int len) |
| 581 | { |
| 582 | g_autoptr(GByteArray) data = g_byte_array_new(); |
| 583 | const char *path; |
| 584 | int err; |
| 585 | |
| 586 | if (len == 0 || req_data[len - 1] != '\0') { |
| 587 | xs_error(s, req_id, tx_id, EINVAL); |
| 588 | return; |
| 589 | } |
| 590 | |
| 591 | path = (const char *)req_data; |
| 592 | |
| 593 | trace_xenstore_mkdir(tx_id, path); |
| 594 | err = xs_impl_read(s->impl, xen_domid, tx_id, path, data); |
| 595 | if (err == ENOENT) { |
| 596 | err = xs_impl_write(s->impl, xen_domid, tx_id, path, data); |
| 597 | } |
| 598 | |
| 599 | if (!err) { |
| 600 | xs_error(s, req_id, tx_id, err); |
| 601 | return; |
| 602 | } |
| 603 | |
| 604 | xs_ok(s, XS_MKDIR, req_id, tx_id); |
| 605 | } |
| 606 | |
| 607 | static void xs_append_strings(XenXenstoreState *s, struct xsd_sockmsg *rsp, |
| 608 | GList *strings, unsigned int start, bool truncate) |
| 609 | { |
| 610 | uint8_t *rsp_data = (uint8_t *)&rsp[1]; |
| 611 | GList *l; |
| 612 | |
| 613 | for (l = strings; l; l = l->next) { |
| 614 | size_t len = strlen(l->data) + 1; /* Including the NUL termination */ |
| 615 | char *str = l->data; |
| 616 | |
| 617 | if (rsp->len + len > XENSTORE_PAYLOAD_MAX) { |
| 618 | if (truncate) { |
| 619 | len = XENSTORE_PAYLOAD_MAX - rsp->len; |
| 620 | if (!len) { |
| 621 | return; |
| 622 | } |
| 623 | } else { |
| 624 | xs_error(s, rsp->req_id, rsp->tx_id, E2BIG); |
| 625 | return; |
| 626 | } |
| 627 | } |
| 628 | |
| 629 | if (start) { |
| 630 | if (start >= len) { |
| 631 | start -= len; |
| 632 | continue; |
| 633 | } |
| 634 | |
| 635 | str += start; |
| 636 | len -= start; |
| 637 | start = 0; |
| 638 | } |
| 639 | |
| 640 | memcpy(&rsp_data[rsp->len], str, len); |
| 641 | rsp->len += len; |
| 642 | } |
| 643 | /* XS_DIRECTORY_PART wants an extra NUL to indicate the end */ |
| 644 | if (truncate && rsp->len < XENSTORE_PAYLOAD_MAX) { |
| 645 | rsp_data[rsp->len++] = '\0'; |
| 646 | } |
| 647 | } |
| 648 | |
| 649 | static void xs_directory(XenXenstoreState *s, unsigned int req_id, |
| 650 | xs_transaction_t tx_id, uint8_t *req_data, |
| 651 | unsigned int len) |
| 652 | { |
| 653 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 654 | GList *items = NULL; |
| 655 | const char *path; |
| 656 | int err; |
| 657 | |
| 658 | if (len == 0 || req_data[len - 1] != '\0') { |
| 659 | xs_error(s, req_id, tx_id, EINVAL); |
| 660 | return; |
| 661 | } |
| 662 | |
| 663 | path = (const char *)req_data; |
| 664 | |
| 665 | trace_xenstore_directory(tx_id, path); |
| 666 | err = xs_impl_directory(s->impl, xen_domid, tx_id, path, NULL, &items); |
| 667 | if (err != 0) { |
| 668 | xs_error(s, req_id, tx_id, err); |
| 669 | return; |
| 670 | } |
| 671 | |
| 672 | rsp->type = XS_DIRECTORY; |
| 673 | rsp->req_id = req_id; |
| 674 | rsp->tx_id = tx_id; |
| 675 | rsp->len = 0; |
| 676 | |
| 677 | xs_append_strings(s, rsp, items, 0, false); |
| 678 | |
| 679 | g_list_free_full(items, g_free); |
| 680 | } |
| 681 | |
| 682 | static void xs_directory_part(XenXenstoreState *s, unsigned int req_id, |
| 683 | xs_transaction_t tx_id, uint8_t *req_data, |
| 684 | unsigned int len) |
| 685 | { |
| 686 | const char *offset_str, *path = (const char *)req_data; |
| 687 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 688 | char *rsp_data = (char *)&rsp[1]; |
| 689 | uint64_t gencnt = 0; |
| 690 | unsigned int offset; |
| 691 | GList *items = NULL; |
| 692 | int err; |
| 693 | |
| 694 | if (len == 0) { |
| 695 | xs_error(s, req_id, tx_id, EINVAL); |
| 696 | return; |
| 697 | } |
| 698 | |
| 699 | while (len--) { |
| 700 | if (*req_data++ == '\0') { |
| 701 | break; |
| 702 | } |
| 703 | if (len == 0) { |
| 704 | xs_error(s, req_id, tx_id, EINVAL); |
| 705 | return; |
| 706 | } |
| 707 | } |
| 708 | |
| 709 | offset_str = (const char *)req_data; |
| 710 | while (len--) { |
| 711 | if (*req_data++ == '\0') { |
| 712 | break; |
| 713 | } |
| 714 | if (len == 0) { |
| 715 | xs_error(s, req_id, tx_id, EINVAL); |
| 716 | return; |
| 717 | } |
| 718 | } |
| 719 | |
| 720 | if (len) { |
| 721 | xs_error(s, req_id, tx_id, EINVAL); |
| 722 | return; |
| 723 | } |
| 724 | |
| 725 | if (qemu_strtoui(offset_str, NULL, 10, &offset) < 0) { |
| 726 | xs_error(s, req_id, tx_id, EINVAL); |
| 727 | return; |
| 728 | } |
| 729 | |
| 730 | trace_xenstore_directory_part(tx_id, path, offset); |
| 731 | err = xs_impl_directory(s->impl, xen_domid, tx_id, path, &gencnt, &items); |
| 732 | if (err != 0) { |
| 733 | xs_error(s, req_id, tx_id, err); |
| 734 | return; |
| 735 | } |
| 736 | |
| 737 | rsp->type = XS_DIRECTORY_PART; |
| 738 | rsp->req_id = req_id; |
| 739 | rsp->tx_id = tx_id; |
| 740 | rsp->len = snprintf(rsp_data, XENSTORE_PAYLOAD_MAX, "%" PRIu64, gencnt) + 1; |
| 741 | |
| 742 | xs_append_strings(s, rsp, items, offset, true); |
| 743 | |
| 744 | g_list_free_full(items, g_free); |
| 745 | } |
| 746 | |
| 747 | static void xs_transaction_start(XenXenstoreState *s, unsigned int req_id, |
| 748 | xs_transaction_t tx_id, uint8_t *req_data, |
| 749 | unsigned int len) |
| 750 | { |
| 751 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 752 | char *rsp_data = (char *)&rsp[1]; |
| 753 | int err; |
| 754 | |
| 755 | if (len != 1 || req_data[0] != '\0') { |
| 756 | xs_error(s, req_id, tx_id, EINVAL); |
| 757 | return; |
| 758 | } |
| 759 | |
| 760 | rsp->type = XS_TRANSACTION_START; |
| 761 | rsp->req_id = req_id; |
| 762 | rsp->tx_id = tx_id; |
| 763 | rsp->len = 0; |
| 764 | |
| 765 | err = xs_impl_transaction_start(s->impl, xen_domid, &tx_id); |
| 766 | if (err) { |
| 767 | xs_error(s, req_id, tx_id, err); |
| 768 | return; |
| 769 | } |
| 770 | |
| 771 | trace_xenstore_transaction_start(tx_id); |
| 772 | |
| 773 | rsp->len = snprintf(rsp_data, XENSTORE_PAYLOAD_MAX, "%u", tx_id); |
| 774 | assert(rsp->len < XENSTORE_PAYLOAD_MAX); |
| 775 | rsp->len++; |
| 776 | } |
| 777 | |
| 778 | static void xs_transaction_end(XenXenstoreState *s, unsigned int req_id, |
| 779 | xs_transaction_t tx_id, uint8_t *req_data, |
| 780 | unsigned int len) |
| 781 | { |
| 782 | bool commit; |
| 783 | int err; |
| 784 | |
| 785 | if (len != 2 || req_data[1] != '\0') { |
| 786 | xs_error(s, req_id, tx_id, EINVAL); |
| 787 | return; |
| 788 | } |
| 789 | |
| 790 | switch (req_data[0]) { |
| 791 | case 'T': |
| 792 | commit = true; |
| 793 | break; |
| 794 | case 'F': |
| 795 | commit = false; |
| 796 | break; |
| 797 | default: |
| 798 | xs_error(s, req_id, tx_id, EINVAL); |
| 799 | return; |
| 800 | } |
| 801 | |
| 802 | trace_xenstore_transaction_end(tx_id, commit); |
| 803 | err = xs_impl_transaction_end(s->impl, xen_domid, tx_id, commit); |
| 804 | if (err) { |
| 805 | xs_error(s, req_id, tx_id, err); |
| 806 | return; |
| 807 | } |
| 808 | |
| 809 | xs_ok(s, XS_TRANSACTION_END, req_id, tx_id); |
| 810 | } |
| 811 | |
| 812 | static void xs_rm(XenXenstoreState *s, unsigned int req_id, |
| 813 | xs_transaction_t tx_id, uint8_t *req_data, unsigned int len) |
| 814 | { |
| 815 | const char *path = (const char *)req_data; |
| 816 | int err; |
| 817 | |
| 818 | if (len == 0 || req_data[len - 1] != '\0') { |
| 819 | xs_error(s, req_id, tx_id, EINVAL); |
| 820 | return; |
| 821 | } |
| 822 | |
| 823 | trace_xenstore_rm(tx_id, path); |
| 824 | err = xs_impl_rm(s->impl, xen_domid, tx_id, path); |
| 825 | if (err) { |
| 826 | xs_error(s, req_id, tx_id, err); |
| 827 | return; |
| 828 | } |
| 829 | |
| 830 | xs_ok(s, XS_RM, req_id, tx_id); |
| 831 | } |
| 832 | |
| 833 | static void xs_get_perms(XenXenstoreState *s, unsigned int req_id, |
| 834 | xs_transaction_t tx_id, uint8_t *req_data, |
| 835 | unsigned int len) |
| 836 | { |
| 837 | const char *path = (const char *)req_data; |
| 838 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 839 | GList *perms = NULL; |
| 840 | int err; |
| 841 | |
| 842 | if (len == 0 || req_data[len - 1] != '\0') { |
| 843 | xs_error(s, req_id, tx_id, EINVAL); |
| 844 | return; |
| 845 | } |
| 846 | |
| 847 | trace_xenstore_get_perms(tx_id, path); |
| 848 | err = xs_impl_get_perms(s->impl, xen_domid, tx_id, path, &perms); |
| 849 | if (err) { |
| 850 | xs_error(s, req_id, tx_id, err); |
| 851 | return; |
| 852 | } |
| 853 | |
| 854 | rsp->type = XS_GET_PERMS; |
| 855 | rsp->req_id = req_id; |
| 856 | rsp->tx_id = tx_id; |
| 857 | rsp->len = 0; |
| 858 | |
| 859 | xs_append_strings(s, rsp, perms, 0, false); |
| 860 | |
| 861 | g_list_free_full(perms, g_free); |
| 862 | } |
| 863 | |
| 864 | static void xs_set_perms(XenXenstoreState *s, unsigned int req_id, |
| 865 | xs_transaction_t tx_id, uint8_t *req_data, |
| 866 | unsigned int len) |
| 867 | { |
| 868 | const char *path = (const char *)req_data; |
| 869 | uint8_t *perm; |
| 870 | GList *perms = NULL; |
| 871 | int err; |
| 872 | |
| 873 | if (len == 0) { |
| 874 | xs_error(s, req_id, tx_id, EINVAL); |
| 875 | return; |
| 876 | } |
| 877 | |
| 878 | while (len--) { |
| 879 | if (*req_data++ == '\0') { |
| 880 | break; |
| 881 | } |
| 882 | if (len == 0) { |
| 883 | xs_error(s, req_id, tx_id, EINVAL); |
| 884 | return; |
| 885 | } |
| 886 | } |
| 887 | |
| 888 | perm = req_data; |
| 889 | while (len--) { |
| 890 | if (*req_data++ == '\0') { |
| 891 | perms = g_list_append(perms, perm); |
| 892 | perm = req_data; |
| 893 | } |
| 894 | } |
| 895 | |
| 896 | /* |
| 897 | * Note that there may be trailing garbage at the end of the buffer. |
| 898 | * This is explicitly permitted by the '?' at the end of the definition: |
| 899 | * |
| 900 | * SET_PERMS <path>|<perm-as-string>|+? |
| 901 | */ |
| 902 | |
| 903 | trace_xenstore_set_perms(tx_id, path); |
| 904 | err = xs_impl_set_perms(s->impl, xen_domid, tx_id, path, perms); |
| 905 | g_list_free(perms); |
| 906 | if (err) { |
| 907 | xs_error(s, req_id, tx_id, err); |
| 908 | return; |
| 909 | } |
| 910 | |
| 911 | xs_ok(s, XS_SET_PERMS, req_id, tx_id); |
| 912 | } |
| 913 | |
| 914 | static void xs_watch(XenXenstoreState *s, unsigned int req_id, |
| 915 | xs_transaction_t tx_id, uint8_t *req_data, |
| 916 | unsigned int len) |
| 917 | { |
| 918 | const char *token, *path = (const char *)req_data; |
| 919 | int err; |
| 920 | |
| 921 | if (len == 0) { |
| 922 | xs_error(s, req_id, tx_id, EINVAL); |
| 923 | return; |
| 924 | } |
| 925 | |
| 926 | while (len--) { |
| 927 | if (*req_data++ == '\0') { |
| 928 | break; |
| 929 | } |
| 930 | if (len == 0) { |
| 931 | xs_error(s, req_id, tx_id, EINVAL); |
| 932 | return; |
| 933 | } |
| 934 | } |
| 935 | |
| 936 | token = (const char *)req_data; |
| 937 | while (len--) { |
| 938 | if (*req_data++ == '\0') { |
| 939 | break; |
| 940 | } |
| 941 | if (len == 0) { |
| 942 | xs_error(s, req_id, tx_id, EINVAL); |
| 943 | return; |
| 944 | } |
| 945 | } |
| 946 | |
| 947 | /* |
| 948 | * Note that there may be trailing garbage at the end of the buffer. |
| 949 | * This is explicitly permitted by the '?' at the end of the definition: |
| 950 | * |
| 951 | * WATCH <wpath>|<token>|? |
| 952 | */ |
| 953 | |
| 954 | trace_xenstore_watch(path, token); |
| 955 | err = xs_impl_watch(s->impl, xen_domid, path, token, fire_watch_cb, s); |
| 956 | if (err) { |
| 957 | xs_error(s, req_id, tx_id, err); |
| 958 | return; |
| 959 | } |
| 960 | |
| 961 | xs_ok(s, XS_WATCH, req_id, tx_id); |
| 962 | } |
| 963 | |
| 964 | static void xs_unwatch(XenXenstoreState *s, unsigned int req_id, |
| 965 | xs_transaction_t tx_id, uint8_t *req_data, |
| 966 | unsigned int len) |
| 967 | { |
| 968 | const char *token, *path = (const char *)req_data; |
| 969 | int err; |
| 970 | |
| 971 | if (len == 0) { |
| 972 | xs_error(s, req_id, tx_id, EINVAL); |
| 973 | return; |
| 974 | } |
| 975 | |
| 976 | while (len--) { |
| 977 | if (*req_data++ == '\0') { |
| 978 | break; |
| 979 | } |
| 980 | if (len == 0) { |
| 981 | xs_error(s, req_id, tx_id, EINVAL); |
| 982 | return; |
| 983 | } |
| 984 | } |
| 985 | |
| 986 | token = (const char *)req_data; |
| 987 | while (len--) { |
| 988 | if (*req_data++ == '\0') { |
| 989 | break; |
| 990 | } |
| 991 | if (len == 0) { |
| 992 | xs_error(s, req_id, tx_id, EINVAL); |
| 993 | return; |
| 994 | } |
| 995 | } |
| 996 | |
| 997 | trace_xenstore_unwatch(path, token); |
| 998 | err = xs_impl_unwatch(s->impl, xen_domid, path, token, fire_watch_cb, s); |
| 999 | if (err) { |
| 1000 | xs_error(s, req_id, tx_id, err); |
| 1001 | return; |
| 1002 | } |
| 1003 | |
| 1004 | xs_ok(s, XS_UNWATCH, req_id, tx_id); |
| 1005 | } |
| 1006 | |
| 1007 | static void xs_reset_watches(XenXenstoreState *s, unsigned int req_id, |
| 1008 | xs_transaction_t tx_id, uint8_t *req_data, |
| 1009 | unsigned int len) |
| 1010 | { |
| 1011 | if (len == 0 || req_data[len - 1] != '\0') { |
| 1012 | xs_error(s, req_id, tx_id, EINVAL); |
| 1013 | return; |
| 1014 | } |
| 1015 | |
| 1016 | trace_xenstore_reset_watches(); |
| 1017 | xs_impl_reset_watches(s->impl, xen_domid); |
| 1018 | |
| 1019 | xs_ok(s, XS_RESET_WATCHES, req_id, tx_id); |
| 1020 | } |
| 1021 | |
| 1022 | static void xs_priv(XenXenstoreState *s, unsigned int req_id, |
| 1023 | xs_transaction_t tx_id, uint8_t *data, |
| 1024 | unsigned int len) |
| 1025 | { |
| 1026 | xs_error(s, req_id, tx_id, EACCES); |
| 1027 | } |
| 1028 | |
| 1029 | static void xs_unimpl(XenXenstoreState *s, unsigned int req_id, |
| 1030 | xs_transaction_t tx_id, uint8_t *data, |
| 1031 | unsigned int len) |
| 1032 | { |
| 1033 | xs_error(s, req_id, tx_id, ENOSYS); |
| 1034 | } |
| 1035 | |
| 1036 | typedef void (*xs_impl)(XenXenstoreState *s, unsigned int req_id, |
| 1037 | xs_transaction_t tx_id, uint8_t *data, |
| 1038 | unsigned int len); |
| 1039 | |
| 1040 | struct xsd_req { |
| 1041 | const char *name; |
| 1042 | xs_impl fn; |
| 1043 | }; |
| 1044 | #define XSD_REQ(_type, _fn) \ |
| 1045 | [_type] = { .name = #_type, .fn = _fn } |
| 1046 | |
| 1047 | struct xsd_req xsd_reqs[] = { |
| 1048 | XSD_REQ(XS_READ, xs_read), |
| 1049 | XSD_REQ(XS_WRITE, xs_write), |
| 1050 | XSD_REQ(XS_MKDIR, xs_mkdir), |
| 1051 | XSD_REQ(XS_DIRECTORY, xs_directory), |
| 1052 | XSD_REQ(XS_DIRECTORY_PART, xs_directory_part), |
| 1053 | XSD_REQ(XS_TRANSACTION_START, xs_transaction_start), |
| 1054 | XSD_REQ(XS_TRANSACTION_END, xs_transaction_end), |
| 1055 | XSD_REQ(XS_RM, xs_rm), |
| 1056 | XSD_REQ(XS_GET_PERMS, xs_get_perms), |
| 1057 | XSD_REQ(XS_SET_PERMS, xs_set_perms), |
| 1058 | XSD_REQ(XS_WATCH, xs_watch), |
| 1059 | XSD_REQ(XS_UNWATCH, xs_unwatch), |
| 1060 | XSD_REQ(XS_CONTROL, xs_priv), |
| 1061 | XSD_REQ(XS_INTRODUCE, xs_priv), |
| 1062 | XSD_REQ(XS_RELEASE, xs_priv), |
| 1063 | XSD_REQ(XS_IS_DOMAIN_INTRODUCED, xs_priv), |
| 1064 | XSD_REQ(XS_RESUME, xs_priv), |
| 1065 | XSD_REQ(XS_SET_TARGET, xs_priv), |
| 1066 | XSD_REQ(XS_RESET_WATCHES, xs_reset_watches), |
| 1067 | }; |
| 1068 | |
| 1069 | static void process_req(XenXenstoreState *s) |
| 1070 | { |
| 1071 | struct xsd_sockmsg *req = (struct xsd_sockmsg *)s->req_data; |
| 1072 | xs_impl handler = NULL; |
| 1073 | |
| 1074 | assert(req_pending(s)); |
| 1075 | assert(!s->rsp_pending); |
| 1076 | |
| 1077 | if (req->type < ARRAY_SIZE(xsd_reqs)) { |
| 1078 | handler = xsd_reqs[req->type].fn; |
| 1079 | } |
| 1080 | if (!handler) { |
| 1081 | handler = &xs_unimpl; |
| 1082 | } |
| 1083 | |
| 1084 | handler(s, req->req_id, req->tx_id, (uint8_t *)&req[1], req->len); |
| 1085 | |
| 1086 | s->rsp_pending = true; |
| 1087 | reset_req(s); |
| 1088 | } |
| 1089 | |
| 1090 | static unsigned int copy_from_ring(XenXenstoreState *s, uint8_t *ptr, |
| 1091 | unsigned int len) |
| 1092 | { |
| 1093 | if (!len) { |
| 1094 | return 0; |
| 1095 | } |
| 1096 | |
| 1097 | XENSTORE_RING_IDX prod = qatomic_read(&s->xs->req_prod); |
| 1098 | XENSTORE_RING_IDX cons = qatomic_read(&s->xs->req_cons); |
| 1099 | unsigned int copied = 0; |
| 1100 | |
| 1101 | /* Ensure the ring contents don't cross the req_prod access. */ |
| 1102 | smp_rmb(); |
| 1103 | |
| 1104 | while (len) { |
| 1105 | unsigned int avail = prod - cons; |
| 1106 | unsigned int offset = MASK_XENSTORE_IDX(cons); |
| 1107 | unsigned int copylen = avail; |
| 1108 | |
| 1109 | if (avail > XENSTORE_RING_SIZE) { |
| 1110 | error_report("XenStore ring handling error"); |
| 1111 | s->fatal_error = true; |
| 1112 | break; |
| 1113 | } else if (avail == 0) { |
| 1114 | break; |
| 1115 | } |
| 1116 | |
| 1117 | if (copylen > len) { |
| 1118 | copylen = len; |
| 1119 | } |
| 1120 | if (copylen > XENSTORE_RING_SIZE - offset) { |
| 1121 | copylen = XENSTORE_RING_SIZE - offset; |
| 1122 | } |
| 1123 | |
| 1124 | memcpy(ptr, &s->xs->req[offset], copylen); |
| 1125 | copied += copylen; |
| 1126 | |
| 1127 | ptr += copylen; |
| 1128 | len -= copylen; |
| 1129 | |
| 1130 | cons += copylen; |
| 1131 | } |
| 1132 | |
| 1133 | /* |
| 1134 | * Not sure this ever mattered except on Alpha, but this barrier |
| 1135 | * is to ensure that the update to req_cons is globally visible |
| 1136 | * only after we have consumed all the data from the ring, and we |
| 1137 | * don't end up seeing data written to the ring *after* the other |
| 1138 | * end sees the update and writes more to the ring. Xen's own |
| 1139 | * xenstored has the same barrier here (although with no comment |
| 1140 | * at all, obviously, because it's Xen code). |
| 1141 | */ |
| 1142 | smp_mb(); |
| 1143 | |
| 1144 | qatomic_set(&s->xs->req_cons, cons); |
| 1145 | |
| 1146 | return copied; |
| 1147 | } |
| 1148 | |
| 1149 | static unsigned int copy_to_ring(XenXenstoreState *s, uint8_t *ptr, |
| 1150 | unsigned int len) |
| 1151 | { |
| 1152 | if (!len) { |
| 1153 | return 0; |
| 1154 | } |
| 1155 | |
| 1156 | XENSTORE_RING_IDX cons = qatomic_read(&s->xs->rsp_cons); |
| 1157 | XENSTORE_RING_IDX prod = qatomic_read(&s->xs->rsp_prod); |
| 1158 | unsigned int copied = 0; |
| 1159 | |
| 1160 | /* |
| 1161 | * This matches the barrier in copy_to_ring() (or the guest's |
| 1162 | * equivalent) between writing the data to the ring and updating |
| 1163 | * rsp_prod. It protects against the pathological case (which |
| 1164 | * again I think never happened except on Alpha) where our |
| 1165 | * subsequent writes to the ring could *cross* the read of |
| 1166 | * rsp_cons and the guest could see the new data when it was |
| 1167 | * intending to read the old. |
| 1168 | */ |
| 1169 | smp_mb(); |
| 1170 | |
| 1171 | while (len) { |
| 1172 | unsigned int avail = cons + XENSTORE_RING_SIZE - prod; |
| 1173 | unsigned int offset = MASK_XENSTORE_IDX(prod); |
| 1174 | unsigned int copylen = len; |
| 1175 | |
| 1176 | if (avail > XENSTORE_RING_SIZE) { |
| 1177 | error_report("XenStore ring handling error"); |
| 1178 | s->fatal_error = true; |
| 1179 | break; |
| 1180 | } else if (avail == 0) { |
| 1181 | break; |
| 1182 | } |
| 1183 | |
| 1184 | if (copylen > avail) { |
| 1185 | copylen = avail; |
| 1186 | } |
| 1187 | if (copylen > XENSTORE_RING_SIZE - offset) { |
| 1188 | copylen = XENSTORE_RING_SIZE - offset; |
| 1189 | } |
| 1190 | |
| 1191 | |
| 1192 | memcpy(&s->xs->rsp[offset], ptr, copylen); |
| 1193 | copied += copylen; |
| 1194 | |
| 1195 | ptr += copylen; |
| 1196 | len -= copylen; |
| 1197 | |
| 1198 | prod += copylen; |
| 1199 | } |
| 1200 | |
| 1201 | /* Ensure the ring contents are seen before rsp_prod update. */ |
| 1202 | smp_wmb(); |
| 1203 | |
| 1204 | qatomic_set(&s->xs->rsp_prod, prod); |
| 1205 | |
| 1206 | return copied; |
| 1207 | } |
| 1208 | |
| 1209 | static unsigned int get_req(XenXenstoreState *s) |
| 1210 | { |
| 1211 | unsigned int copied = 0; |
| 1212 | |
| 1213 | if (s->fatal_error) { |
| 1214 | return 0; |
| 1215 | } |
| 1216 | |
| 1217 | assert(!req_pending(s)); |
| 1218 | |
| 1219 | if (s->req_offset < XENSTORE_HEADER_SIZE) { |
| 1220 | void *ptr = s->req_data + s->req_offset; |
| 1221 | unsigned int len = XENSTORE_HEADER_SIZE; |
| 1222 | unsigned int copylen = copy_from_ring(s, ptr, len); |
| 1223 | |
| 1224 | copied += copylen; |
| 1225 | s->req_offset += copylen; |
| 1226 | } |
| 1227 | |
| 1228 | if (s->req_offset >= XENSTORE_HEADER_SIZE) { |
| 1229 | struct xsd_sockmsg *req = (struct xsd_sockmsg *)s->req_data; |
| 1230 | |
| 1231 | if (req->len > (uint32_t)XENSTORE_PAYLOAD_MAX) { |
| 1232 | error_report("Illegal XenStore request"); |
| 1233 | s->fatal_error = true; |
| 1234 | return 0; |
| 1235 | } |
| 1236 | |
| 1237 | void *ptr = s->req_data + s->req_offset; |
| 1238 | unsigned int len = XENSTORE_HEADER_SIZE + req->len - s->req_offset; |
| 1239 | unsigned int copylen = copy_from_ring(s, ptr, len); |
| 1240 | |
| 1241 | copied += copylen; |
| 1242 | s->req_offset += copylen; |
| 1243 | } |
| 1244 | |
| 1245 | return copied; |
| 1246 | } |
| 1247 | |
| 1248 | static unsigned int put_rsp(XenXenstoreState *s) |
| 1249 | { |
| 1250 | if (s->fatal_error) { |
| 1251 | return 0; |
| 1252 | } |
| 1253 | |
| 1254 | assert(s->rsp_pending); |
| 1255 | |
| 1256 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 1257 | assert(s->rsp_offset < XENSTORE_HEADER_SIZE + rsp->len); |
| 1258 | |
| 1259 | void *ptr = s->rsp_data + s->rsp_offset; |
| 1260 | unsigned int len = XENSTORE_HEADER_SIZE + rsp->len - s->rsp_offset; |
| 1261 | unsigned int copylen = copy_to_ring(s, ptr, len); |
| 1262 | |
| 1263 | s->rsp_offset += copylen; |
| 1264 | |
| 1265 | /* Have we produced a complete response? */ |
| 1266 | if (s->rsp_offset == XENSTORE_HEADER_SIZE + rsp->len) { |
| 1267 | reset_rsp(s); |
| 1268 | } |
| 1269 | |
| 1270 | return copylen; |
| 1271 | } |
| 1272 | |
| 1273 | static void deliver_watch(XenXenstoreState *s, const char *path, |
| 1274 | const char *token) |
| 1275 | { |
| 1276 | struct xsd_sockmsg *rsp = (struct xsd_sockmsg *)s->rsp_data; |
| 1277 | uint8_t *rsp_data = (uint8_t *)&rsp[1]; |
| 1278 | unsigned int len; |
| 1279 | |
| 1280 | assert(!s->rsp_pending); |
| 1281 | |
| 1282 | trace_xenstore_watch_event(path, token); |
| 1283 | |
| 1284 | rsp->type = XS_WATCH_EVENT; |
| 1285 | rsp->req_id = 0; |
| 1286 | rsp->tx_id = 0; |
| 1287 | rsp->len = 0; |
| 1288 | |
| 1289 | len = strlen(path); |
| 1290 | |
| 1291 | /* XENSTORE_ABS/REL_PATH_MAX should ensure there can be no overflow */ |
| 1292 | assert(rsp->len + len < XENSTORE_PAYLOAD_MAX); |
| 1293 | |
| 1294 | memcpy(&rsp_data[rsp->len], path, len); |
| 1295 | rsp->len += len; |
| 1296 | rsp_data[rsp->len] = '\0'; |
| 1297 | rsp->len++; |
| 1298 | |
| 1299 | len = strlen(token); |
| 1300 | /* |
| 1301 | * It is possible for the guest to have chosen a token that will |
| 1302 | * not fit (along with the patch) into a watch event. We have no |
| 1303 | * choice but to drop the event if this is the case. |
| 1304 | */ |
| 1305 | if (rsp->len + len >= XENSTORE_PAYLOAD_MAX) { |
| 1306 | return; |
| 1307 | } |
| 1308 | |
| 1309 | memcpy(&rsp_data[rsp->len], token, len); |
| 1310 | rsp->len += len; |
| 1311 | rsp_data[rsp->len] = '\0'; |
| 1312 | rsp->len++; |
| 1313 | |
| 1314 | s->rsp_pending = true; |
| 1315 | } |
| 1316 | |
| 1317 | struct watch_event { |
| 1318 | char *path; |
| 1319 | char *token; |
| 1320 | }; |
| 1321 | |
| 1322 | static void free_watch_event(struct watch_event *ev) |
| 1323 | { |
| 1324 | if (ev) { |
| 1325 | g_free(ev->path); |
| 1326 | g_free(ev->token); |
| 1327 | g_free(ev); |
| 1328 | } |
| 1329 | } |
| 1330 | |
| 1331 | static void queue_watch(XenXenstoreState *s, const char *path, |
| 1332 | const char *token) |
| 1333 | { |
| 1334 | struct watch_event *ev = g_new0(struct watch_event, 1); |
| 1335 | |
| 1336 | ev->path = g_strdup(path); |
| 1337 | ev->token = g_strdup(token); |
| 1338 | |
| 1339 | s->watch_events = g_list_append(s->watch_events, ev); |
| 1340 | } |
| 1341 | |
| 1342 | static void fire_watch_cb(void *opaque, const char *path, const char *token) |
| 1343 | { |
| 1344 | XenXenstoreState *s = opaque; |
| 1345 | |
| 1346 | assert(bql_locked()); |
| 1347 | |
| 1348 | /* |
| 1349 | * If there's a response pending, we obviously can't scribble over |
| 1350 | * it. But if there's a request pending, it has dibs on the buffer |
| 1351 | * too. |
| 1352 | * |
| 1353 | * In the common case of a watch firing due to backend activity |
| 1354 | * when the ring was otherwise idle, we should be able to copy the |
| 1355 | * strings directly into the rsp_data and thence the actual ring, |
| 1356 | * without needing to perform any allocations and queue them. |
| 1357 | */ |
| 1358 | if (s->rsp_pending || req_pending(s)) { |
| 1359 | queue_watch(s, path, token); |
| 1360 | } else { |
| 1361 | deliver_watch(s, path, token); |
| 1362 | /* |
| 1363 | * Attempt to queue the message into the actual ring, and send |
| 1364 | * the event channel notification if any bytes are copied. |
| 1365 | */ |
| 1366 | if (s->rsp_pending && put_rsp(s) > 0) { |
| 1367 | xen_be_evtchn_notify(s->eh, s->be_port); |
| 1368 | } |
| 1369 | } |
| 1370 | } |
| 1371 | |
| 1372 | static void process_watch_events(XenXenstoreState *s) |
| 1373 | { |
| 1374 | struct watch_event *ev = s->watch_events->data; |
| 1375 | |
| 1376 | deliver_watch(s, ev->path, ev->token); |
| 1377 | |
| 1378 | s->watch_events = g_list_remove(s->watch_events, ev); |
| 1379 | free_watch_event(ev); |
| 1380 | } |
| 1381 | |
| 1382 | static void xen_xenstore_event(void *opaque) |
| 1383 | { |
| 1384 | XenXenstoreState *s = opaque; |
| 1385 | evtchn_port_t port = xen_be_evtchn_pending(s->eh); |
| 1386 | unsigned int copied_to, copied_from; |
| 1387 | bool processed, notify = false; |
| 1388 | |
| 1389 | if (port != s->be_port) { |
| 1390 | return; |
| 1391 | } |
| 1392 | |
| 1393 | /* We know this is a no-op. */ |
| 1394 | xen_be_evtchn_unmask(s->eh, port); |
| 1395 | |
| 1396 | do { |
| 1397 | copied_to = copied_from = 0; |
| 1398 | processed = false; |
| 1399 | |
| 1400 | if (!s->rsp_pending && s->watch_events) { |
| 1401 | process_watch_events(s); |
| 1402 | } |
| 1403 | |
| 1404 | if (s->rsp_pending) { |
| 1405 | copied_to = put_rsp(s); |
| 1406 | } |
| 1407 | |
| 1408 | if (!req_pending(s)) { |
| 1409 | copied_from = get_req(s); |
| 1410 | } |
| 1411 | |
| 1412 | if (req_pending(s) && !s->rsp_pending && !s->watch_events) { |
| 1413 | process_req(s); |
| 1414 | processed = true; |
| 1415 | } |
| 1416 | |
| 1417 | notify |= copied_to || copied_from; |
| 1418 | } while (copied_to || copied_from || processed); |
| 1419 | |
| 1420 | if (notify) { |
| 1421 | xen_be_evtchn_notify(s->eh, s->be_port); |
| 1422 | } |
| 1423 | } |
| 1424 | |
| 1425 | static void alloc_guest_port(XenXenstoreState *s) |
| 1426 | { |
| 1427 | struct evtchn_alloc_unbound alloc = { |
| 1428 | .dom = DOMID_SELF, |
| 1429 | .remote_dom = DOMID_QEMU, |
| 1430 | }; |
| 1431 | |
| 1432 | if (!xen_evtchn_alloc_unbound_op(&alloc)) { |
| 1433 | s->guest_port = alloc.port; |
| 1434 | } |
| 1435 | } |
| 1436 | |
| 1437 | int xen_xenstore_reset(void) |
| 1438 | { |
| 1439 | XenXenstoreState *s = xen_xenstore_singleton; |
| 1440 | int console_port; |
| 1441 | GList *perms; |
| 1442 | int err; |
| 1443 | |
| 1444 | if (!s) { |
| 1445 | return -ENOTSUP; |
| 1446 | } |
| 1447 | |
| 1448 | s->req_offset = s->rsp_offset = 0; |
| 1449 | s->rsp_pending = false; |
| 1450 | |
| 1451 | if (!memory_region_is_mapped(&s->xenstore_page)) { |
| 1452 | uint64_t gpa = XEN_SPECIAL_PFN(XENSTORE) << TARGET_PAGE_BITS; |
| 1453 | xen_overlay_do_map_page(&s->xenstore_page, gpa); |
| 1454 | } |
| 1455 | |
| 1456 | alloc_guest_port(s); |
| 1457 | |
| 1458 | /* |
| 1459 | * As qemu/dom0, bind to the guest's port. For incoming migration, this |
| 1460 | * will be unbound as the guest's evtchn table is overwritten. We then |
| 1461 | * rebind to the correct guest port in xen_xenstore_post_load(). |
| 1462 | */ |
| 1463 | err = xen_be_evtchn_bind_interdomain(s->eh, xen_domid, s->guest_port); |
| 1464 | if (err < 0) { |
| 1465 | return err; |
| 1466 | } |
| 1467 | s->be_port = err; |
| 1468 | |
| 1469 | /* Create frontend store nodes */ |
| 1470 | perms = g_list_append(NULL, xs_perm_as_string(XS_PERM_NONE, DOMID_QEMU)); |
| 1471 | perms = g_list_append(perms, xs_perm_as_string(XS_PERM_READ, xen_domid)); |
| 1472 | |
| 1473 | relpath_printf(s, perms, "store/port", "%u", s->guest_port); |
| 1474 | relpath_printf(s, perms, "store/ring-ref", "%lu", |
| 1475 | XEN_SPECIAL_PFN(XENSTORE)); |
| 1476 | |
| 1477 | console_port = xen_primary_console_get_port(); |
| 1478 | if (console_port) { |
| 1479 | relpath_printf(s, perms, "console/ring-ref", "%lu", |
| 1480 | XEN_SPECIAL_PFN(CONSOLE)); |
| 1481 | relpath_printf(s, perms, "console/port", "%u", console_port); |
| 1482 | relpath_printf(s, perms, "console/state", "%u", XenbusStateInitialised); |
| 1483 | } |
| 1484 | |
| 1485 | g_list_free_full(perms, g_free); |
| 1486 | |
| 1487 | /* |
| 1488 | * We don't actually access the guest's page through the grant, because |
| 1489 | * this isn't real Xen, and we can just use the page we gave it in the |
| 1490 | * first place. Map the grant anyway, mostly for cosmetic purposes so |
| 1491 | * it *looks* like it's in use in the guest-visible grant table. |
| 1492 | */ |
| 1493 | s->gt = qemu_xen_gnttab_open(); |
| 1494 | uint32_t xs_gntref = GNTTAB_RESERVED_XENSTORE; |
| 1495 | s->granted_xs = qemu_xen_gnttab_map_refs(s->gt, 1, xen_domid, &xs_gntref, |
| 1496 | PROT_READ | PROT_WRITE); |
| 1497 | |
| 1498 | return 0; |
| 1499 | } |
| 1500 | |
| 1501 | struct qemu_xs_handle { |
| 1502 | XenstoreImplState *impl; |
| 1503 | GList *watches; |
| 1504 | QEMUBH *watch_bh; |
| 1505 | }; |
| 1506 | |
| 1507 | struct qemu_xs_watch { |
| 1508 | struct qemu_xs_handle *h; |
| 1509 | char *path; |
| 1510 | xs_watch_fn fn; |
| 1511 | void *opaque; |
| 1512 | GList *events; |
| 1513 | }; |
| 1514 | |
| 1515 | static char *xs_be_get_domain_path(struct qemu_xs_handle *h, unsigned int domid) |
| 1516 | { |
| 1517 | return g_strdup_printf("/local/domain/%u", domid); |
| 1518 | } |
| 1519 | |
| 1520 | static char **xs_be_directory(struct qemu_xs_handle *h, xs_transaction_t t, |
| 1521 | const char *path, unsigned int *num) |
| 1522 | { |
| 1523 | GList *items = NULL, *l; |
| 1524 | unsigned int i = 0; |
| 1525 | char **items_ret; |
| 1526 | int err; |
| 1527 | |
| 1528 | err = xs_impl_directory(h->impl, DOMID_QEMU, t, path, NULL, &items); |
| 1529 | if (err) { |
| 1530 | errno = err; |
| 1531 | return NULL; |
| 1532 | } |
| 1533 | |
| 1534 | items_ret = g_new0(char *, g_list_length(items) + 1); |
| 1535 | *num = 0; |
| 1536 | for (l = items; l; l = l->next) { |
| 1537 | items_ret[i++] = l->data; |
| 1538 | (*num)++; |
| 1539 | } |
| 1540 | g_list_free(items); |
| 1541 | return items_ret; |
| 1542 | } |
| 1543 | |
| 1544 | static void *xs_be_read(struct qemu_xs_handle *h, xs_transaction_t t, |
| 1545 | const char *path, unsigned int *len) |
| 1546 | { |
| 1547 | GByteArray *data = g_byte_array_new(); |
| 1548 | bool free_segment = false; |
| 1549 | int err; |
| 1550 | |
| 1551 | err = xs_impl_read(h->impl, DOMID_QEMU, t, path, data); |
| 1552 | if (err) { |
| 1553 | free_segment = true; |
| 1554 | errno = err; |
| 1555 | } else { |
| 1556 | if (len) { |
| 1557 | *len = data->len; |
| 1558 | } |
| 1559 | /* The xen-bus-helper code expects to get NUL terminated string! */ |
| 1560 | g_byte_array_append(data, (void *)"", 1); |
| 1561 | } |
| 1562 | |
| 1563 | return g_byte_array_free(data, free_segment); |
| 1564 | } |
| 1565 | |
| 1566 | static bool xs_be_write(struct qemu_xs_handle *h, xs_transaction_t t, |
| 1567 | const char *path, const void *data, unsigned int len) |
| 1568 | { |
| 1569 | GByteArray *gdata = g_byte_array_new(); |
| 1570 | int err; |
| 1571 | |
| 1572 | g_byte_array_append(gdata, data, len); |
| 1573 | err = xs_impl_write(h->impl, DOMID_QEMU, t, path, gdata); |
| 1574 | g_byte_array_unref(gdata); |
| 1575 | if (err) { |
| 1576 | errno = err; |
| 1577 | return false; |
| 1578 | } |
| 1579 | return true; |
| 1580 | } |
| 1581 | |
| 1582 | static bool xs_be_create(struct qemu_xs_handle *h, xs_transaction_t t, |
| 1583 | unsigned int owner, unsigned int domid, |
| 1584 | unsigned int perms, const char *path) |
| 1585 | { |
| 1586 | g_autoptr(GByteArray) data = g_byte_array_new(); |
| 1587 | GList *perms_list = NULL; |
| 1588 | int err; |
| 1589 | |
| 1590 | /* mkdir does this */ |
| 1591 | err = xs_impl_read(h->impl, DOMID_QEMU, t, path, data); |
| 1592 | if (err == ENOENT) { |
| 1593 | err = xs_impl_write(h->impl, DOMID_QEMU, t, path, data); |
| 1594 | } |
| 1595 | if (err) { |
| 1596 | errno = err; |
| 1597 | return false; |
| 1598 | } |
| 1599 | |
| 1600 | perms_list = g_list_append(perms_list, |
| 1601 | xs_perm_as_string(XS_PERM_NONE, owner)); |
| 1602 | perms_list = g_list_append(perms_list, |
| 1603 | xs_perm_as_string(perms, domid)); |
| 1604 | |
| 1605 | err = xs_impl_set_perms(h->impl, DOMID_QEMU, t, path, perms_list); |
| 1606 | g_list_free_full(perms_list, g_free); |
| 1607 | if (err) { |
| 1608 | errno = err; |
| 1609 | return false; |
| 1610 | } |
| 1611 | return true; |
| 1612 | } |
| 1613 | |
| 1614 | static bool xs_be_destroy(struct qemu_xs_handle *h, xs_transaction_t t, |
| 1615 | const char *path) |
| 1616 | { |
| 1617 | int err = xs_impl_rm(h->impl, DOMID_QEMU, t, path); |
| 1618 | if (err) { |
| 1619 | errno = err; |
| 1620 | return false; |
| 1621 | } |
| 1622 | return true; |
| 1623 | } |
| 1624 | |
| 1625 | static void be_watch_bh(void *_h) |
| 1626 | { |
| 1627 | struct qemu_xs_handle *h = _h; |
| 1628 | GList *l; |
| 1629 | |
| 1630 | for (l = h->watches; l; l = l->next) { |
| 1631 | struct qemu_xs_watch *w = l->data; |
| 1632 | |
| 1633 | while (w->events) { |
| 1634 | struct watch_event *ev = w->events->data; |
| 1635 | |
| 1636 | w->fn(w->opaque, ev->path); |
| 1637 | |
| 1638 | w->events = g_list_remove(w->events, ev); |
| 1639 | free_watch_event(ev); |
| 1640 | } |
| 1641 | } |
| 1642 | } |
| 1643 | |
| 1644 | static void xs_be_watch_cb(void *opaque, const char *path, const char *token) |
| 1645 | { |
| 1646 | struct watch_event *ev = g_new0(struct watch_event, 1); |
| 1647 | struct qemu_xs_watch *w = opaque; |
| 1648 | |
| 1649 | /* We don't care about the token */ |
| 1650 | ev->path = g_strdup(path); |
| 1651 | w->events = g_list_append(w->events, ev); |
| 1652 | |
| 1653 | qemu_bh_schedule(w->h->watch_bh); |
| 1654 | } |
| 1655 | |
| 1656 | static struct qemu_xs_watch *xs_be_watch(struct qemu_xs_handle *h, |
| 1657 | const char *path, xs_watch_fn fn, |
| 1658 | void *opaque) |
| 1659 | { |
| 1660 | struct qemu_xs_watch *w = g_new0(struct qemu_xs_watch, 1); |
| 1661 | int err; |
| 1662 | |
| 1663 | w->h = h; |
| 1664 | w->fn = fn; |
| 1665 | w->opaque = opaque; |
| 1666 | |
| 1667 | err = xs_impl_watch(h->impl, DOMID_QEMU, path, NULL, xs_be_watch_cb, w); |
| 1668 | if (err) { |
| 1669 | errno = err; |
| 1670 | g_free(w); |
| 1671 | return NULL; |
| 1672 | } |
| 1673 | |
| 1674 | w->path = g_strdup(path); |
| 1675 | h->watches = g_list_append(h->watches, w); |
| 1676 | return w; |
| 1677 | } |
| 1678 | |
| 1679 | static void xs_be_unwatch(struct qemu_xs_handle *h, struct qemu_xs_watch *w) |
| 1680 | { |
| 1681 | xs_impl_unwatch(h->impl, DOMID_QEMU, w->path, NULL, xs_be_watch_cb, w); |
| 1682 | |
| 1683 | h->watches = g_list_remove(h->watches, w); |
| 1684 | g_list_free_full(w->events, (GDestroyNotify)free_watch_event); |
| 1685 | g_free(w->path); |
| 1686 | g_free(w); |
| 1687 | } |
| 1688 | |
| 1689 | static xs_transaction_t xs_be_transaction_start(struct qemu_xs_handle *h) |
| 1690 | { |
| 1691 | unsigned int new_tx = XBT_NULL; |
| 1692 | int err = xs_impl_transaction_start(h->impl, DOMID_QEMU, &new_tx); |
| 1693 | if (err) { |
| 1694 | errno = err; |
| 1695 | return XBT_NULL; |
| 1696 | } |
| 1697 | return new_tx; |
| 1698 | } |
| 1699 | |
| 1700 | static bool xs_be_transaction_end(struct qemu_xs_handle *h, xs_transaction_t t, |
| 1701 | bool abort) |
| 1702 | { |
| 1703 | int err = xs_impl_transaction_end(h->impl, DOMID_QEMU, t, !abort); |
| 1704 | if (err) { |
| 1705 | errno = err; |
| 1706 | return false; |
| 1707 | } |
| 1708 | return true; |
| 1709 | } |
| 1710 | |
| 1711 | static struct qemu_xs_handle *xs_be_open(void) |
| 1712 | { |
| 1713 | XenXenstoreState *s = xen_xenstore_singleton; |
| 1714 | struct qemu_xs_handle *h; |
| 1715 | |
| 1716 | if (!s || !s->impl) { |
| 1717 | errno = -ENOSYS; |
| 1718 | return NULL; |
| 1719 | } |
| 1720 | |
| 1721 | h = g_new0(struct qemu_xs_handle, 1); |
| 1722 | h->impl = s->impl; |
| 1723 | |
| 1724 | h->watch_bh = aio_bh_new(qemu_get_aio_context(), be_watch_bh, h); |
| 1725 | |
| 1726 | return h; |
| 1727 | } |
| 1728 | |
| 1729 | static void xs_be_close(struct qemu_xs_handle *h) |
| 1730 | { |
| 1731 | while (h->watches) { |
| 1732 | struct qemu_xs_watch *w = h->watches->data; |
| 1733 | xs_be_unwatch(h, w); |
| 1734 | } |
| 1735 | |
| 1736 | qemu_bh_delete(h->watch_bh); |
| 1737 | g_free(h); |
| 1738 | } |
| 1739 | |
| 1740 | static struct xenstore_backend_ops emu_xenstore_backend_ops = { |
| 1741 | .open = xs_be_open, |
| 1742 | .close = xs_be_close, |
| 1743 | .get_domain_path = xs_be_get_domain_path, |
| 1744 | .directory = xs_be_directory, |
| 1745 | .read = xs_be_read, |
| 1746 | .write = xs_be_write, |
| 1747 | .create = xs_be_create, |
| 1748 | .destroy = xs_be_destroy, |
| 1749 | .watch = xs_be_watch, |
| 1750 | .unwatch = xs_be_unwatch, |
| 1751 | .transaction_start = xs_be_transaction_start, |
| 1752 | .transaction_end = xs_be_transaction_end, |
| 1753 | }; |