src/libsystemd/sd-bus/bus-internal.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include <pthread.h>
   5
   6 #include "sd-bus.h"
   7
   8 #include "bus-error.h"
   9 #include "bus-kernel.h"
  10 #include "bus-match.h"
  11 #include "def.h"
  12 #include "hashmap.h"
  13 #include "list.h"
  14 #include "prioq.h"
  15 #include "socket-util.h"
  16 #include "time-util.h"
  17
  18 /* Note that we use the new /run prefix here (instead of /var/run) since we require them to be aliases and
  19  * that way we become independent of /var being mounted */
  20 #define DEFAULT_SYSTEM_BUS_ADDRESS "unix:path=/run/dbus/system_bus_socket"
  21 #define DEFAULT_USER_BUS_ADDRESS_FMT "unix:path=%s/bus"
  22
  23 struct reply_callback {
  24         sd_bus_message_handler_t callback;
  25         usec_t timeout_usec; /* this is a relative timeout until we reach the BUS_HELLO state, and an absolute one right after */
  26         uint64_t cookie;
  27         unsigned prioq_idx;
  28 };
  29
  30 struct filter_callback {
  31         sd_bus_message_handler_t callback;
  32
  33         unsigned last_iteration;
  34
  35         LIST_FIELDS(struct filter_callback, callbacks);
  36 };
  37
  38 struct match_callback {
  39         sd_bus_message_handler_t callback;
  40         sd_bus_message_handler_t install_callback;
  41
  42         sd_bus_slot *install_slot; /* The AddMatch() call */
  43
  44         unsigned last_iteration;
  45
  46         /* Don't dispatch this slot with with messages that arrived in any iteration before or at the this
  47          * one. We use this to ensure that matches don't apply "retroactively" and thus can confuse the
  48          * caller: matches will only match incoming messages from the moment on the match was installed. */
  49         uint64_t after;
  50
  51         char *match_string;
  52
  53         struct bus_match_node *match_node;
  54 };
  55
  56 struct node {
  57         char *path;
  58         struct node *parent;
  59         LIST_HEAD(struct node, child);
  60         LIST_FIELDS(struct node, siblings);
  61
  62         LIST_HEAD(struct node_callback, callbacks);
  63         LIST_HEAD(struct node_vtable, vtables);
  64         LIST_HEAD(struct node_enumerator, enumerators);
  65         LIST_HEAD(struct node_object_manager, object_managers);
  66 };
  67
  68 struct node_callback {
  69         struct node *node;
  70
  71         bool is_fallback:1;
  72         unsigned last_iteration;
  73
  74         sd_bus_message_handler_t callback;
  75
  76         LIST_FIELDS(struct node_callback, callbacks);
  77 };
  78
  79 struct node_enumerator {
  80         struct node *node;
  81
  82         sd_bus_node_enumerator_t callback;
  83
  84         unsigned last_iteration;
  85
  86         LIST_FIELDS(struct node_enumerator, enumerators);
  87 };
  88
  89 struct node_object_manager {
  90         struct node *node;
  91
  92         LIST_FIELDS(struct node_object_manager, object_managers);
  93 };
  94
  95 struct node_vtable {
  96         struct node *node;
  97
  98         bool is_fallback:1;
  99         unsigned last_iteration;
 100
 101         char *interface;
 102         const sd_bus_vtable *vtable;
 103         sd_bus_object_find_t find;
 104
 105         LIST_FIELDS(struct node_vtable, vtables);
 106 };
 107
 108 struct vtable_member {
 109         const char *path;
 110         const char *interface;
 111         const char *member;
 112         struct node_vtable *parent;
 113         unsigned last_iteration;
 114         const sd_bus_vtable *vtable;
 115 };
 116
 117 typedef enum BusSlotType {
 118         BUS_REPLY_CALLBACK,
 119         BUS_FILTER_CALLBACK,
 120         BUS_MATCH_CALLBACK,
 121         BUS_NODE_CALLBACK,
 122         BUS_NODE_ENUMERATOR,
 123         BUS_NODE_VTABLE,
 124         BUS_NODE_OBJECT_MANAGER,
 125         _BUS_SLOT_INVALID = -1,
 126 } BusSlotType;
 127
 128 struct sd_bus_slot {
 129         unsigned n_ref;
 130         BusSlotType type:5;
 131
 132         /* Slots can be "floating" or not. If they are not floating (the usual case) then they reference the bus object
 133          * they are associated with. This means the bus object stays allocated at least as long as there is a slot
 134          * around associated with it. If it is floating, then the slot's lifecycle is bound to the lifecycle of the
 135          * bus: it will be disconnected from the bus when the bus is destroyed, and it keeping the slot reffed hence
 136          * won't mean the bus stays reffed too. Internally this means the reference direction is reversed: floating
 137          * slots objects are referenced by the bus object, and not vice versa. */
 138         bool floating:1;
 139
 140         bool match_added:1;
 141
 142         sd_bus *bus;
 143         void *userdata;
 144         sd_bus_destroy_t destroy_callback;
 145
 146         char *description;
 147
 148         LIST_FIELDS(sd_bus_slot, slots);
 149
 150         union {
 151                 struct reply_callback reply_callback;
 152                 struct filter_callback filter_callback;
 153                 struct match_callback match_callback;
 154                 struct node_callback node_callback;
 155                 struct node_enumerator node_enumerator;
 156                 struct node_object_manager node_object_manager;
 157                 struct node_vtable node_vtable;
 158         };
 159 };
 160
 161 enum bus_state {
 162         BUS_UNSET,
 163         BUS_WATCH_BIND,      /* waiting for the socket to appear via inotify */
 164         BUS_OPENING,         /* the kernel's connect() is still not ready */
 165         BUS_AUTHENTICATING,  /* we are currently in the "SASL" authorization phase of dbus */
 166         BUS_HELLO,           /* we are waiting for the Hello() response */
 167         BUS_RUNNING,
 168         BUS_CLOSING,
 169         BUS_CLOSED,
 170         _BUS_STATE_MAX,
 171 };
 172
 173 static inline bool BUS_IS_OPEN(enum bus_state state) {
 174         return state > BUS_UNSET && state < BUS_CLOSING;
 175 }
 176
 177 enum bus_auth {
 178         _BUS_AUTH_INVALID,
 179         BUS_AUTH_EXTERNAL,
 180         BUS_AUTH_ANONYMOUS
 181 };
 182
 183 struct sd_bus {
 184         unsigned n_ref;
 185
 186         enum bus_state state;
 187         int input_fd, output_fd;
 188         int inotify_fd;
 189         int message_version;
 190         int message_endian;
 191
 192         bool can_fds:1;
 193         bool bus_client:1;
 194         bool ucred_valid:1;
 195         bool is_server:1;
 196         bool anonymous_auth:1;
 197         bool prefer_readv:1;
 198         bool prefer_writev:1;
 199         bool match_callbacks_modified:1;
 200         bool filter_callbacks_modified:1;
 201         bool nodes_modified:1;
 202         bool trusted:1;
 203         bool manual_peer_interface:1;
 204         bool is_system:1;
 205         bool is_user:1;
 206         bool allow_interactive_authorization:1;
 207         bool exit_on_disconnect:1;
 208         bool exited:1;
 209         bool exit_triggered:1;
 210         bool is_local:1;
 211         bool watch_bind:1;
 212         bool is_monitor:1;
 213         bool accept_fd:1;
 214         bool attach_timestamp:1;
 215         bool connected_signal:1;
 216         bool close_on_exit:1;
 217
 218         signed int use_memfd:2;
 219
 220         void *rbuffer;
 221         size_t rbuffer_size;
 222
 223         sd_bus_message **rqueue;
 224         size_t rqueue_size;
 225         size_t rqueue_allocated;
 226
 227         sd_bus_message **wqueue;
 228         size_t wqueue_size;
 229         size_t windex;
 230         size_t wqueue_allocated;
 231
 232         uint64_t cookie;
 233         uint64_t read_counter; /* A counter for each incoming msg */
 234
 235         char *unique_name;
 236         uint64_t unique_id;
 237
 238         struct bus_match_node match_callbacks;
 239         Prioq *reply_callbacks_prioq;
 240         OrderedHashmap *reply_callbacks;
 241         LIST_HEAD(struct filter_callback, filter_callbacks);
 242
 243         Hashmap *nodes;
 244         Hashmap *vtable_methods;
 245         Hashmap *vtable_properties;
 246
 247         union sockaddr_union sockaddr;
 248         socklen_t sockaddr_size;
 249
 250         pid_t nspid;
 251         char *machine;
 252
 253         sd_id128_t server_id;
 254
 255         char *address;
 256         unsigned address_index;
 257
 258         int last_connect_error;
 259
 260         enum bus_auth auth;
 261         unsigned auth_index;
 262         struct iovec auth_iovec[3];
 263         size_t auth_rbegin;
 264         char *auth_buffer;
 265         usec_t auth_timeout;
 266
 267         struct ucred ucred;
 268         char *label;
 269         gid_t *groups;
 270         size_t n_groups;
 271
 272         uint64_t creds_mask;
 273
 274         int *fds;
 275         size_t n_fds;
 276
 277         char *exec_path;
 278         char **exec_argv;
 279
 280         /* We do locking around the memfd cache, since we want to
 281          * allow people to process a sd_bus_message in a different
 282          * thread then it was generated on and free it there. Since
 283          * adding something to the memfd cache might happen when a
 284          * message is released, we hence need to protect this bit with
 285          * a mutex. */
 286         pthread_mutex_t memfd_cache_mutex;
 287         struct memfd_cache memfd_cache[MEMFD_CACHE_MAX];
 288         unsigned n_memfd_cache;
 289
 290         pid_t original_pid;
 291         pid_t busexec_pid;
 292
 293         unsigned iteration_counter;
 294
 295         sd_event_source *input_io_event_source;
 296         sd_event_source *output_io_event_source;
 297         sd_event_source *time_event_source;
 298         sd_event_source *quit_event_source;
 299         sd_event_source *inotify_event_source;
 300         sd_event *event;
 301         int event_priority;
 302
 303         pid_t tid;
 304
 305         sd_bus_message *current_message;
 306         sd_bus_slot *current_slot;
 307         sd_bus_message_handler_t current_handler;
 308         void *current_userdata;
 309
 310         sd_bus **default_bus_ptr;
 311
 312         char *description;
 313         char *patch_sender;
 314
 315         sd_bus_track *track_queue;
 316
 317         LIST_HEAD(sd_bus_slot, slots);
 318         LIST_HEAD(sd_bus_track, tracks);
 319
 320         int *inotify_watches;
 321         size_t n_inotify_watches;
 322
 323         /* zero means use value specified by $SYSTEMD_BUS_TIMEOUT= environment variable or built-in default */
 324         usec_t method_call_timeout;
 325 };
 326
 327 /* For method calls we timeout at 25s, like in the D-Bus reference implementation */
 328 #define BUS_DEFAULT_TIMEOUT ((usec_t) (25 * USEC_PER_SEC))
 329
 330 /* For the authentication phase we grant 90s, to provide extra room during boot, when RNGs and such are not filled up
 331  * with enough entropy yet and might delay the boot */
 332 #define BUS_AUTH_TIMEOUT ((usec_t) DEFAULT_TIMEOUT_USEC)
 333
 334 #define BUS_WQUEUE_MAX (384*1024)
 335 #define BUS_RQUEUE_MAX (384*1024)
 336
 337 #define BUS_MESSAGE_SIZE_MAX (128*1024*1024)
 338 #define BUS_AUTH_SIZE_MAX (64*1024)
 339 /* Note that the D-Bus specification states that bus paths shall have no size limit. We enforce here one
 340  * anyway, since truly unbounded strings are a security problem. The limit we pick is relatively large however,
 341  * to not clash unnecessarily with real-life applications. */
 342 #define BUS_PATH_SIZE_MAX (64*1024)
 343
 344 #define BUS_CONTAINER_DEPTH 128
 345
 346 /* Defined by the specification as maximum size of an array in bytes */
 347 #define BUS_ARRAY_MAX_SIZE 67108864
 348
 349 #define BUS_FDS_MAX 1024
 350
 351 #define BUS_EXEC_ARGV_MAX 256
 352
 353 bool interface_name_is_valid(const char *p) _pure_;
 354 bool service_name_is_valid(const char *p) _pure_;
 355 bool member_name_is_valid(const char *p) _pure_;
 356 bool object_path_is_valid(const char *p) _pure_;
 357 char *object_path_startswith(const char *a, const char *b) _pure_;
 358
 359 bool namespace_complex_pattern(const char *pattern, const char *value) _pure_;
 360 bool path_complex_pattern(const char *pattern, const char *value) _pure_;
 361
 362 bool namespace_simple_pattern(const char *pattern, const char *value) _pure_;
 363 bool path_simple_pattern(const char *pattern, const char *value) _pure_;
 364
 365 int bus_message_type_from_string(const char *s, uint8_t *u) _pure_;
 366 const char *bus_message_type_to_string(uint8_t u) _pure_;
 367
 368 #define error_name_is_valid interface_name_is_valid
 369
 370 sd_bus *bus_resolve(sd_bus *bus);
 371
 372 int bus_ensure_running(sd_bus *bus);
 373 int bus_start_running(sd_bus *bus);
 374 int bus_next_address(sd_bus *bus);
 375
 376 int bus_seal_synthetic_message(sd_bus *b, sd_bus_message *m);
 377
 378 int bus_rqueue_make_room(sd_bus *bus);
 379
 380 bool bus_pid_changed(sd_bus *bus);
 381
 382 char *bus_address_escape(const char *v);
 383
 384 int bus_attach_io_events(sd_bus *b);
 385 int bus_attach_inotify_event(sd_bus *b);
 386
 387 void bus_close_inotify_fd(sd_bus *b);
 388 void bus_close_io_fds(sd_bus *b);
 389
 390 #define OBJECT_PATH_FOREACH_PREFIX(prefix, path)                        \
 391         for (char *_slash = ({ strcpy((prefix), (path)); streq((prefix), "/") ? NULL : strrchr((prefix), '/'); }) ; \
 392              _slash && ((_slash[(_slash) == (prefix)] = 0), true);       \
 393              _slash = streq((prefix), "/") ? NULL : strrchr((prefix), '/'))
 394
 395 /* If we are invoking callbacks of a bus object, ensure unreffing the
 396  * bus from the callback doesn't destroy the object we are working on */
 397 #define BUS_DONT_DESTROY(bus) \
 398         _cleanup_(sd_bus_unrefp) _unused_ sd_bus *_dont_destroy_##bus = sd_bus_ref(bus)
 399
 400 int bus_set_address_system(sd_bus *bus);
 401 int bus_set_address_user(sd_bus *bus);
 402 int bus_set_address_system_remote(sd_bus *b, const char *host);
 403 int bus_set_address_system_machine(sd_bus *b, const char *machine);
 404
 405 int bus_maybe_reply_error(sd_bus_message *m, int r, sd_bus_error *error);
 406
 407 #define bus_assert_return(expr, r, error)                               \
 408         do {                                                            \
 409                 if (!assert_log(expr, #expr))                           \
 410                         return sd_bus_error_set_errno(error, r);        \
 411         } while (false)
 412
 413 void bus_enter_closing(sd_bus *bus);
 414
 415 void bus_set_state(sd_bus *bus, enum bus_state state);