src/libsystemd-bus/bus-kernel.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #ifdef HAVE_VALGRIND_MEMCHECK_H
  23 #include <valgrind/memcheck.h>
  24 #endif
  25
  26 #include <fcntl.h>
  27 #include <malloc.h>
  28 #include <sys/mman.h>
  29
  30 #include "util.h"
  31
  32 #include "bus-internal.h"
  33 #include "bus-message.h"
  34 #include "bus-kernel.h"
  35 #include "bus-bloom.h"
  36
  37 int bus_kernel_parse_unique_name(const char *s, uint64_t *id) {
  38         int r;
  39
  40         assert(s);
  41         assert(id);
  42
  43         if (!startswith(s, ":1."))
  44                 return 0;
  45
  46         r = safe_atou64(s + 3, id);
  47         if (r < 0)
  48                 return r;
  49
  50         return 1;
  51 }
  52
  53 static void append_payload_vec(struct kdbus_item **d, const void *p, size_t sz) {
  54         assert(d);
  55         assert(sz > 0);
  56
  57         *d = ALIGN8_PTR(*d);
  58
  59         /* Note that p can be NULL, which encodes a region full of
  60          * zeroes, which is useful to optimize certain padding
  61          * conditions */
  62
  63         (*d)->size = offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec);
  64         (*d)->type = KDBUS_MSG_PAYLOAD_VEC;
  65         (*d)->vec.address = PTR_TO_UINT64(p);
  66         (*d)->vec.size = sz;
  67
  68         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
  69 }
  70
  71 static void append_payload_memfd(struct kdbus_item **d, int memfd, size_t sz) {
  72         assert(d);
  73         assert(memfd >= 0);
  74         assert(sz > 0);
  75
  76         *d = ALIGN8_PTR(*d);
  77         (*d)->size = offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd);
  78         (*d)->type = KDBUS_MSG_PAYLOAD_MEMFD;
  79         (*d)->memfd.fd = memfd;
  80         (*d)->memfd.size = sz;
  81
  82         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
  83 }
  84
  85 static void append_destination(struct kdbus_item **d, const char *s, size_t length) {
  86         assert(d);
  87         assert(s);
  88
  89         *d = ALIGN8_PTR(*d);
  90
  91         (*d)->size = offsetof(struct kdbus_item, str) + length + 1;
  92         (*d)->type = KDBUS_MSG_DST_NAME;
  93         memcpy((*d)->str, s, length + 1);
  94
  95         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
  96 }
  97
  98 static void* append_bloom(struct kdbus_item **d, size_t length) {
  99         void *r;
 100
 101         assert(d);
 102
 103         *d = ALIGN8_PTR(*d);
 104
 105         (*d)->size = offsetof(struct kdbus_item, data) + length;
 106         (*d)->type = KDBUS_MSG_BLOOM;
 107         r = (*d)->data;
 108
 109         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
 110
 111         return r;
 112 }
 113
 114 static void append_fds(struct kdbus_item **d, const int fds[], unsigned n_fds) {
 115         assert(d);
 116         assert(fds);
 117         assert(n_fds > 0);
 118
 119         *d = ALIGN8_PTR(*d);
 120         (*d)->size = offsetof(struct kdbus_item, fds) + sizeof(int) * n_fds;
 121         (*d)->type = KDBUS_MSG_FDS;
 122         memcpy((*d)->fds, fds, sizeof(int) * n_fds);
 123
 124         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
 125 }
 126
 127 static int bus_message_setup_bloom(sd_bus_message *m, void *bloom) {
 128         unsigned i;
 129         int r;
 130
 131         assert(m);
 132         assert(bloom);
 133
 134         memset(bloom, 0, BLOOM_SIZE);
 135
 136         bloom_add_pair(bloom, "message-type", bus_message_type_to_string(m->header->type));
 137
 138         if (m->interface)
 139                 bloom_add_pair(bloom, "interface", m->interface);
 140         if (m->member)
 141                 bloom_add_pair(bloom, "member", m->member);
 142         if (m->path) {
 143                 bloom_add_pair(bloom, "path", m->path);
 144                 bloom_add_pair(bloom, "path-slash-prefix", m->path);
 145                 bloom_add_prefixes(bloom, "path-slash-prefix", m->path, '/');
 146         }
 147
 148         r = sd_bus_message_rewind(m, true);
 149         if (r < 0)
 150                 return r;
 151
 152         for (i = 0; i < 64; i++) {
 153                 char type;
 154                 const char *t;
 155                 char buf[sizeof("arg")-1 + 2 + sizeof("-slash-prefix")];
 156                 char *e;
 157
 158                 r = sd_bus_message_peek_type(m, &type, NULL);
 159                 if (r < 0)
 160                         return r;
 161
 162                 if (type != SD_BUS_TYPE_STRING &&
 163                     type != SD_BUS_TYPE_OBJECT_PATH &&
 164                     type != SD_BUS_TYPE_SIGNATURE)
 165                         break;
 166
 167                 r = sd_bus_message_read_basic(m, type, &t);
 168                 if (r < 0)
 169                         return r;
 170
 171                 e = stpcpy(buf, "arg");
 172                 if (i < 10)
 173                         *(e++) = '0' + i;
 174                 else {
 175                         *(e++) = '0' + (i / 10);
 176                         *(e++) = '0' + (i % 10);
 177                 }
 178
 179                 *e = 0;
 180                 bloom_add_pair(bloom, buf, t);
 181
 182                 strcpy(e, "-dot-prefix");
 183                 bloom_add_prefixes(bloom, buf, t, '.');
 184                 strcpy(e, "-slash-prefix");
 185                 bloom_add_prefixes(bloom, buf, t, '/');
 186         }
 187
 188         return 0;
 189 }
 190
 191 static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
 192         struct bus_body_part *part;
 193         struct kdbus_item *d;
 194         bool well_known;
 195         uint64_t unique;
 196         size_t sz, dl;
 197         unsigned i;
 198         int r;
 199
 200         assert(b);
 201         assert(m);
 202         assert(m->sealed);
 203
 204         if (m->kdbus)
 205                 return 0;
 206
 207         if (m->destination) {
 208                 r = bus_kernel_parse_unique_name(m->destination, &unique);
 209                 if (r < 0)
 210                         return r;
 211
 212                 well_known = r == 0;
 213         } else
 214                 well_known = false;
 215
 216         sz = offsetof(struct kdbus_msg, items);
 217
 218         assert_cc(ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec)) ==
 219                   ALIGN8(offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd)));
 220
 221         /* Add in fixed header, fields header and payload */
 222         sz += (1 + m->n_body_parts) *
 223                 ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec));
 224
 225         /* Add space for bloom filter */
 226         sz += ALIGN8(offsetof(struct kdbus_item, data) + BLOOM_SIZE);
 227
 228         /* Add in well-known destination header */
 229         if (well_known) {
 230                 dl = strlen(m->destination);
 231                 sz += ALIGN8(offsetof(struct kdbus_item, str) + dl + 1);
 232         }
 233
 234         /* Add space for unix fds */
 235         if (m->n_fds > 0)
 236                 sz += ALIGN8(offsetof(struct kdbus_item, fds) + sizeof(int)*m->n_fds);
 237
 238         m->kdbus = memalign(8, sz);
 239         if (!m->kdbus) {
 240                 r = -ENOMEM;
 241                 goto fail;
 242         }
 243
 244         m->free_kdbus = true;
 245         memset(m->kdbus, 0, sz);
 246
 247         m->kdbus->flags =
 248                 ((m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED) ? 0 : KDBUS_MSG_FLAGS_EXPECT_REPLY) |
 249                 ((m->header->flags & SD_BUS_MESSAGE_NO_AUTO_START) ? KDBUS_MSG_FLAGS_NO_AUTO_START : 0);
 250         m->kdbus->dst_id =
 251                 well_known ? 0 :
 252                 m->destination ? unique : KDBUS_DST_ID_BROADCAST;
 253         m->kdbus->payload_type = KDBUS_PAYLOAD_DBUS1;
 254         m->kdbus->cookie = m->header->serial;
 255
 256         m->kdbus->timeout_ns = m->timeout * NSEC_PER_USEC;
 257
 258         d = m->kdbus->items;
 259
 260         if (well_known)
 261                 append_destination(&d, m->destination, dl);
 262
 263         append_payload_vec(&d, m->header, BUS_MESSAGE_BODY_BEGIN(m));
 264
 265         MESSAGE_FOREACH_PART(part, i, m) {
 266                 if (part->is_zero) {
 267                         /* If this is padding then simply send a
 268                          * vector with a NULL data pointer which the
 269                          * kernel will just pass through. This is the
 270                          * most efficient way to encode zeroes */
 271
 272                         append_payload_vec(&d, NULL, part->size);
 273                         continue;
 274                 }
 275
 276                 if (part->memfd >= 0 && part->sealed && m->destination) {
 277                         /* Try to send a memfd, if the part is
 278                          * sealed and this is not a broadcast. Since we can only  */
 279
 280                         append_payload_memfd(&d, part->memfd, part->size);
 281                         continue;
 282                 }
 283
 284                 /* Otherwise let's send a vector to the actual data,
 285                  * for that we need to map it first. */
 286                 r = bus_body_part_map(part);
 287                 if (r < 0)
 288                         goto fail;
 289
 290                 append_payload_vec(&d, part->data, part->size);
 291         }
 292
 293         if (m->kdbus->dst_id == KDBUS_DST_ID_BROADCAST) {
 294                 void *p;
 295
 296                 p = append_bloom(&d, BLOOM_SIZE);
 297                 r = bus_message_setup_bloom(m, p);
 298                 if (r < 0)
 299                         goto fail;
 300         }
 301
 302         if (m->n_fds > 0)
 303                 append_fds(&d, m->fds, m->n_fds);
 304
 305         m->kdbus->size = (uint8_t*) d - (uint8_t*) m->kdbus;
 306         assert(m->kdbus->size <= sz);
 307
 308         return 0;
 309
 310 fail:
 311         m->poisoned = true;
 312         return r;
 313 }
 314
 315 int bus_kernel_take_fd(sd_bus *b) {
 316         uint8_t h[ALIGN8(sizeof(struct kdbus_cmd_hello)) +
 317                   ALIGN8(KDBUS_ITEM_HEADER_SIZE) +
 318                   ALIGN8(sizeof(struct kdbus_vec))] = {};
 319
 320         struct kdbus_cmd_hello *hello = (struct kdbus_cmd_hello*) h;
 321
 322         int r;
 323
 324         assert(b);
 325
 326         if (b->is_server)
 327                 return -EINVAL;
 328
 329         if (!b->kdbus_buffer) {
 330                 b->kdbus_buffer = mmap(NULL, KDBUS_POOL_SIZE, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
 331                 if (b->kdbus_buffer == MAP_FAILED) {
 332                         b->kdbus_buffer = NULL;
 333                         return -errno;
 334                 }
 335         }
 336
 337         hello->size = sizeof(h);
 338         hello->conn_flags = b->hello_flags;
 339
 340         hello->items[0].type = KDBUS_HELLO_POOL;
 341         hello->items[0].size = KDBUS_ITEM_HEADER_SIZE + sizeof(struct kdbus_vec);
 342         hello->items[0].vec.address = (uint64_t) b->kdbus_buffer;
 343         hello->items[0].vec.size = KDBUS_POOL_SIZE;
 344
 345         r = ioctl(b->input_fd, KDBUS_CMD_HELLO, hello);
 346         if (r < 0)
 347                 return -errno;
 348
 349         /* The higher 32bit of both flags fields are considered
 350          * 'incompatible flags'. Refuse them all for now. */
 351         if (hello->bus_flags > 0xFFFFFFFFULL ||
 352             hello->conn_flags > 0xFFFFFFFFULL)
 353                 return -ENOTSUP;
 354
 355         if (hello->bloom_size != BLOOM_SIZE)
 356                 return -ENOTSUP;
 357
 358         if (asprintf(&b->unique_name, ":1.%llu", (unsigned long long) hello->id) < 0)
 359                 return -ENOMEM;
 360
 361         b->is_kernel = true;
 362         b->bus_client = true;
 363         b->can_fds = !!(hello->conn_flags & KDBUS_HELLO_ACCEPT_FD);
 364
 365         r = bus_start_running(b);
 366         if (r < 0)
 367                 return r;
 368
 369         return 1;
 370 }
 371
 372 int bus_kernel_connect(sd_bus *b) {
 373         assert(b);
 374         assert(b->input_fd < 0);
 375         assert(b->output_fd < 0);
 376         assert(b->kernel);
 377
 378         if (b->is_server)
 379                 return -EINVAL;
 380
 381         b->input_fd = open(b->kernel, O_RDWR|O_NOCTTY|O_CLOEXEC);
 382         if (b->input_fd < 0)
 383                 return -errno;
 384
 385         b->output_fd = b->input_fd;
 386
 387         return bus_kernel_take_fd(b);
 388 }
 389
 390 int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m) {
 391         int r;
 392
 393         assert(bus);
 394         assert(m);
 395         assert(bus->state == BUS_RUNNING);
 396
 397         r = bus_message_setup_kmsg(bus, m);
 398         if (r < 0)
 399                 return r;
 400
 401         r = ioctl(bus->output_fd, KDBUS_CMD_MSG_SEND, m->kdbus);
 402         if (r < 0)
 403                 return errno == EAGAIN ? 0 : -errno;
 404
 405         return 1;
 406 }
 407
 408 static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
 409         struct kdbus_item *d;
 410
 411         assert(bus);
 412         assert(k);
 413
 414         ioctl(bus->input_fd, KDBUS_CMD_MSG_RELEASE, k);
 415
 416         KDBUS_ITEM_FOREACH(d, k) {
 417
 418                 if (d->type == KDBUS_MSG_FDS)
 419                         close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int));
 420                 else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD)
 421                         close_nointr_nofail(d->memfd.fd);
 422         }
 423 }
 424
 425 static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_message **ret) {
 426         sd_bus_message *m = NULL;
 427         struct kdbus_item *d;
 428         unsigned n_fds = 0;
 429         _cleanup_free_ int *fds = NULL;
 430         struct bus_header *h = NULL;
 431         size_t total, n_bytes = 0, idx = 0;
 432         const char *destination = NULL, *seclabel = NULL;
 433         int r;
 434
 435         assert(bus);
 436         assert(k);
 437         assert(ret);
 438
 439         if (k->payload_type != KDBUS_PAYLOAD_DBUS1)
 440                 return 0;
 441
 442         KDBUS_ITEM_FOREACH(d, k) {
 443                 size_t l;
 444
 445                 l = d->size - offsetof(struct kdbus_item, data);
 446
 447                 if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
 448
 449                         if (!h) {
 450                                 h = UINT64_TO_PTR(d->vec.address);
 451
 452                                 if (!bus_header_is_complete(h, d->vec.size))
 453                                         return -EBADMSG;
 454                         }
 455
 456                         n_bytes += d->vec.size;
 457
 458                 } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) {
 459
 460                         if (!h)
 461                                 return -EBADMSG;
 462
 463                         n_bytes += d->memfd.size;
 464
 465                 } else if (d->type == KDBUS_MSG_FDS) {
 466                         int *f;
 467                         unsigned j;
 468
 469                         j = l / sizeof(int);
 470                         f = realloc(fds, sizeof(int) * (n_fds + j));
 471                         if (!f)
 472                                 return -ENOMEM;
 473
 474                         fds = f;
 475                         memcpy(fds + n_fds, d->fds, sizeof(int) * j);
 476                         n_fds += j;
 477
 478                 } else if (d->type == KDBUS_MSG_SRC_SECLABEL)
 479                         seclabel = d->str;
 480         }
 481
 482         if (!h)
 483                 return -EBADMSG;
 484
 485         r = bus_header_message_size(h, &total);
 486         if (r < 0)
 487                 return r;
 488
 489         if (n_bytes != total)
 490                 return -EBADMSG;
 491
 492         r = bus_message_from_header(h, sizeof(struct bus_header), fds, n_fds, NULL, seclabel, 0, &m);
 493         if (r < 0)
 494                 return r;
 495
 496         KDBUS_ITEM_FOREACH(d, k) {
 497                 size_t l;
 498
 499                 l = d->size - offsetof(struct kdbus_item, data);
 500
 501                 if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
 502                         size_t begin_body;
 503
 504                         begin_body = BUS_MESSAGE_BODY_BEGIN(m);
 505
 506                         if (idx + d->vec.size > begin_body) {
 507                                 struct bus_body_part *part;
 508
 509                                 /* Contains body material */
 510
 511                                 part = message_append_part(m);
 512                                 if (!part) {
 513                                         r = -ENOMEM;
 514                                         goto fail;
 515                                 }
 516
 517                                 if (idx >= begin_body) {
 518                                         part->data = UINT64_TO_PTR(d->vec.address);
 519                                         part->size = d->vec.size;
 520                                 } else {
 521                                         part->data = d->vec.address != 0 ? (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx) : NULL;
 522                                         part->size = d->vec.size - (begin_body - idx);
 523                                 }
 524
 525                                 part->is_zero = d->vec.address == 0;
 526                                 part->sealed = true;
 527                         }
 528
 529                         idx += d->vec.size;
 530                 } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) {
 531                         struct bus_body_part *part;
 532
 533                         if (idx < BUS_MESSAGE_BODY_BEGIN(m)) {
 534                                 r = -EBADMSG;
 535                                 goto fail;
 536                         }
 537
 538                         part = message_append_part(m);
 539                         if (!part) {
 540                                 r = -ENOMEM;
 541                                 goto fail;
 542                         }
 543
 544                         part->memfd = d->memfd.fd;
 545                         part->size = d->memfd.size;
 546                         part->sealed = true;
 547
 548                         idx += d->memfd.size;
 549
 550                 } else if (d->type == KDBUS_MSG_SRC_CREDS) {
 551                         m->pid_starttime = d->creds.starttime / NSEC_PER_USEC;
 552                         m->uid = d->creds.uid;
 553                         m->gid = d->creds.gid;
 554                         m->pid = d->creds.pid;
 555                         m->tid = d->creds.tid;
 556                         m->uid_valid = m->gid_valid = true;
 557                 } else if (d->type == KDBUS_MSG_TIMESTAMP) {
 558                         m->realtime = d->timestamp.realtime_ns / NSEC_PER_USEC;
 559                         m->monotonic = d->timestamp.monotonic_ns / NSEC_PER_USEC;
 560                 } else if (d->type == KDBUS_MSG_SRC_PID_COMM)
 561                         m->comm = d->str;
 562                 else if (d->type == KDBUS_MSG_SRC_TID_COMM)
 563                         m->tid_comm = d->str;
 564                 else if (d->type == KDBUS_MSG_SRC_EXE)
 565                         m->exe = d->str;
 566                 else if (d->type == KDBUS_MSG_SRC_CMDLINE) {
 567                         m->cmdline = d->str;
 568                         m->cmdline_length = l;
 569                 } else if (d->type == KDBUS_MSG_SRC_CGROUP)
 570                         m->cgroup = d->str;
 571                 else if (d->type == KDBUS_MSG_SRC_AUDIT)
 572                         m->audit = &d->audit;
 573                 else if (d->type == KDBUS_MSG_SRC_CAPS) {
 574                         m->capability = d->data;
 575                         m->capability_size = l;
 576                 } else if (d->type == KDBUS_MSG_DST_NAME)
 577                         destination = d->str;
 578                 else if (d->type != KDBUS_MSG_FDS &&
 579                            d->type != KDBUS_MSG_SRC_SECLABEL)
 580                         log_debug("Got unknown field from kernel %llu", d->type);
 581         }
 582
 583         r = bus_message_parse_fields(m);
 584         if (r < 0)
 585                 goto fail;
 586
 587         if (k->src_id == KDBUS_SRC_ID_KERNEL)
 588                 m->sender = "org.freedesktop.DBus";
 589         else {
 590                 snprintf(m->sender_buffer, sizeof(m->sender_buffer), ":1.%llu", (unsigned long long) k->src_id);
 591                 m->sender = m->sender_buffer;
 592         }
 593
 594         if (!m->destination) {
 595                 if (destination)
 596                         m->destination = destination;
 597                 else if (k->dst_id != KDBUS_DST_ID_WELL_KNOWN_NAME &&
 598                          k->dst_id != KDBUS_DST_ID_BROADCAST) {
 599                         snprintf(m->destination_buffer, sizeof(m->destination_buffer), ":1.%llu", (unsigned long long) k->dst_id);
 600                         m->destination = m->destination_buffer;
 601                 }
 602         }
 603
 604         /* We take possession of the kmsg struct now */
 605         m->kdbus = k;
 606         m->bus = sd_bus_ref(bus);
 607         m->release_kdbus = true;
 608         m->free_fds = true;
 609
 610         fds = NULL;
 611
 612         *ret = m;
 613         return 1;
 614
 615 fail:
 616         if (m) {
 617                 struct bus_body_part *part;
 618                 unsigned i;
 619
 620                 /* Make sure the memfds are not freed twice */
 621                 MESSAGE_FOREACH_PART(part, i, m)
 622                         if (part->memfd >= 0)
 623                                 part->memfd = -1;
 624
 625                 sd_bus_message_unref(m);
 626         }
 627
 628         return r;
 629 }
 630
 631 int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) {
 632         uint64_t addr;
 633         struct kdbus_msg *k;
 634         int r;
 635
 636         assert(bus);
 637         assert(m);
 638
 639         r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, &addr);
 640         if (r < 0) {
 641                 if (errno == EAGAIN)
 642                         return 0;
 643
 644                 return -errno;
 645         }
 646         k = UINT64_TO_PTR(addr);
 647
 648         r = bus_kernel_make_message(bus, k, m);
 649         if (r <= 0)
 650                 close_kdbus_msg(bus, k);
 651
 652         return r < 0 ? r : 1;
 653 }
 654
 655 int bus_kernel_create(const char *name, char **s) {
 656         struct kdbus_cmd_bus_make *make;
 657         struct kdbus_item *n, *cg;
 658         size_t l;
 659         int fd;
 660         char *p;
 661
 662         assert(name);
 663         assert(s);
 664
 665         fd = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC);
 666         if (fd < 0)
 667                 return -errno;
 668
 669         l = strlen(name);
 670         make = alloca0(offsetof(struct kdbus_cmd_bus_make, items) +
 671                        KDBUS_ITEM_HEADER_SIZE + sizeof(uint64_t) +
 672                        KDBUS_ITEM_HEADER_SIZE + DECIMAL_STR_MAX(uid_t) + 1 + l + 1);
 673
 674         cg = make->items;
 675         cg->type = KDBUS_MAKE_CGROUP;
 676         cg->data64[0] = 1;
 677         cg->size = KDBUS_ITEM_HEADER_SIZE + sizeof(uint64_t);
 678
 679         n = KDBUS_ITEM_NEXT(cg);
 680         n->type = KDBUS_MAKE_NAME;
 681         sprintf(n->str, "%lu-%s", (unsigned long) getuid(), name);
 682         n->size = KDBUS_ITEM_HEADER_SIZE + strlen(n->str) + 1;
 683
 684         make->size = offsetof(struct kdbus_cmd_bus_make, items) + cg->size + n->size;
 685         make->flags = KDBUS_MAKE_POLICY_OPEN;
 686         make->bus_flags = 0;
 687         make->bloom_size = BLOOM_SIZE;
 688         assert_cc(BLOOM_SIZE % 8 == 0);
 689
 690         p = strjoin("/dev/kdbus/", n->str, "/bus", NULL);
 691         if (!p)
 692                 return -ENOMEM;
 693
 694         if (ioctl(fd, KDBUS_CMD_BUS_MAKE, make) < 0) {
 695                 close_nointr_nofail(fd);
 696                 free(p);
 697                 return -errno;
 698         }
 699
 700         if (s)
 701                 *s = p;
 702
 703         return fd;
 704 }
 705
 706 int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *size) {
 707         struct memfd_cache *c;
 708         int fd;
 709
 710         assert(address);
 711         assert(size);
 712
 713         if (!bus || !bus->is_kernel)
 714                 return -ENOTSUP;
 715
 716         assert_se(pthread_mutex_lock(&bus->memfd_cache_mutex) == 0);
 717
 718         if (bus->n_memfd_cache <= 0) {
 719                 int r;
 720
 721                 assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
 722
 723                 r = ioctl(bus->input_fd, KDBUS_CMD_MEMFD_NEW, &fd);
 724                 if (r < 0)
 725                         return -errno;
 726
 727                 *address = NULL;
 728                 *size = 0;
 729                 return fd;
 730         }
 731
 732         c = &bus->memfd_cache[-- bus->n_memfd_cache];
 733
 734         assert(c->fd >= 0);
 735         assert(c->size == 0 || c->address);
 736
 737         *address = c->address;
 738         *size = c->size;
 739         fd = c->fd;
 740
 741         assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
 742
 743         return fd;
 744 }
 745
 746 static void close_and_munmap(int fd, void *address, size_t size) {
 747         if (size > 0)
 748                 assert_se(munmap(address, PAGE_ALIGN(size)) == 0);
 749
 750         close_nointr_nofail(fd);
 751 }
 752
 753 void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t size) {
 754         struct memfd_cache *c;
 755
 756         assert(fd >= 0);
 757         assert(size == 0 || address);
 758
 759         if (!bus || !bus->is_kernel) {
 760                 close_and_munmap(fd, address, size);
 761                 return;
 762         }
 763
 764         assert_se(pthread_mutex_lock(&bus->memfd_cache_mutex) == 0);
 765
 766         if (bus->n_memfd_cache >= ELEMENTSOF(bus->memfd_cache)) {
 767                 assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
 768
 769                 close_and_munmap(fd, address, size);
 770                 return;
 771         }
 772
 773         c = &bus->memfd_cache[bus->n_memfd_cache++];
 774         c->fd = fd;
 775         c->address = address;
 776
 777         /* If overly long, let's return a bit to the OS */
 778         if (size > MEMFD_CACHE_ITEM_SIZE_MAX) {
 779                 uint64_t sz = MEMFD_CACHE_ITEM_SIZE_MAX;
 780
 781                 ioctl(bus->input_fd, KDBUS_CMD_MEMFD_SIZE_SET, &sz);
 782
 783                 c->size = MEMFD_CACHE_ITEM_SIZE_MAX;
 784         } else
 785                 c->size = size;
 786
 787         assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
 788 }
 789
 790 void bus_kernel_flush_memfd(sd_bus *b) {
 791         unsigned i;
 792
 793         assert(b);
 794
 795         for (i = 0; i < b->n_memfd_cache; i++) {
 796                 if (b->memfd_cache[i].size > 0)
 797                         assert_se(munmap(b->memfd_cache[i].address, PAGE_ALIGN(b->memfd_cache[i].size)) == 0);
 798
 799                 close_nointr_nofail(b->memfd_cache[i].fd);
 800         }
 801 }