src/libsystemd/sd-daemon/sd-daemon.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <limits.h>
   5 #include <mqueue.h>
   6 #include <netinet/in.h>
   7 #include <stdarg.h>
   8 #include <stddef.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <sys/socket.h>
  12 #include <sys/stat.h>
  13 #include <sys/un.h>
  14 #include <unistd.h>
  15
  16 #include "sd-daemon.h"
  17
  18 #include "alloc-util.h"
  19 #include "fd-util.h"
  20 #include "fs-util.h"
  21 #include "io-util.h"
  22 #include "parse-util.h"
  23 #include "path-util.h"
  24 #include "process-util.h"
  25 #include "socket-util.h"
  26 #include "strv.h"
  27 #include "util.h"
  28
  29 #define SNDBUF_SIZE (8*1024*1024)
  30
  31 static void unsetenv_all(bool unset_environment) {
  32
  33         if (!unset_environment)
  34                 return;
  35
  36         unsetenv("LISTEN_PID");
  37         unsetenv("LISTEN_FDS");
  38         unsetenv("LISTEN_FDNAMES");
  39 }
  40
  41 _public_ int sd_listen_fds(int unset_environment) {
  42         const char *e;
  43         int n, r, fd;
  44         pid_t pid;
  45
  46         e = getenv("LISTEN_PID");
  47         if (!e) {
  48                 r = 0;
  49                 goto finish;
  50         }
  51
  52         r = parse_pid(e, &pid);
  53         if (r < 0)
  54                 goto finish;
  55
  56         /* Is this for us? */
  57         if (getpid_cached() != pid) {
  58                 r = 0;
  59                 goto finish;
  60         }
  61
  62         e = getenv("LISTEN_FDS");
  63         if (!e) {
  64                 r = 0;
  65                 goto finish;
  66         }
  67
  68         r = safe_atoi(e, &n);
  69         if (r < 0)
  70                 goto finish;
  71
  72         assert_cc(SD_LISTEN_FDS_START < INT_MAX);
  73         if (n <= 0 || n > INT_MAX - SD_LISTEN_FDS_START) {
  74                 r = -EINVAL;
  75                 goto finish;
  76         }
  77
  78         for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd ++) {
  79                 r = fd_cloexec(fd, true);
  80                 if (r < 0)
  81                         goto finish;
  82         }
  83
  84         r = n;
  85
  86 finish:
  87         unsetenv_all(unset_environment);
  88         return r;
  89 }
  90
  91 _public_ int sd_listen_fds_with_names(int unset_environment, char ***names) {
  92         _cleanup_strv_free_ char **l = NULL;
  93         bool have_names;
  94         int n_names = 0, n_fds;
  95         const char *e;
  96         int r;
  97
  98         if (!names)
  99                 return sd_listen_fds(unset_environment);
 100
 101         e = getenv("LISTEN_FDNAMES");
 102         if (e) {
 103                 n_names = strv_split_extract(&l, e, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
 104                 if (n_names < 0) {
 105                         unsetenv_all(unset_environment);
 106                         return n_names;
 107                 }
 108
 109                 have_names = true;
 110         } else
 111                 have_names = false;
 112
 113         n_fds = sd_listen_fds(unset_environment);
 114         if (n_fds <= 0)
 115                 return n_fds;
 116
 117         if (have_names) {
 118                 if (n_names != n_fds)
 119                         return -EINVAL;
 120         } else {
 121                 r = strv_extend_n(&l, "unknown", n_fds);
 122                 if (r < 0)
 123                         return r;
 124         }
 125
 126         *names = TAKE_PTR(l);
 127
 128         return n_fds;
 129 }
 130
 131 _public_ int sd_is_fifo(int fd, const char *path) {
 132         struct stat st_fd;
 133
 134         assert_return(fd >= 0, -EBADF);
 135
 136         if (fstat(fd, &st_fd) < 0)
 137                 return -errno;
 138
 139         if (!S_ISFIFO(st_fd.st_mode))
 140                 return 0;
 141
 142         if (path) {
 143                 struct stat st_path;
 144
 145                 if (stat(path, &st_path) < 0) {
 146
 147                         if (IN_SET(errno, ENOENT, ENOTDIR))
 148                                 return 0;
 149
 150                         return -errno;
 151                 }
 152
 153                 return
 154                         st_path.st_dev == st_fd.st_dev &&
 155                         st_path.st_ino == st_fd.st_ino;
 156         }
 157
 158         return 1;
 159 }
 160
 161 _public_ int sd_is_special(int fd, const char *path) {
 162         struct stat st_fd;
 163
 164         assert_return(fd >= 0, -EBADF);
 165
 166         if (fstat(fd, &st_fd) < 0)
 167                 return -errno;
 168
 169         if (!S_ISREG(st_fd.st_mode) && !S_ISCHR(st_fd.st_mode))
 170                 return 0;
 171
 172         if (path) {
 173                 struct stat st_path;
 174
 175                 if (stat(path, &st_path) < 0) {
 176
 177                         if (IN_SET(errno, ENOENT, ENOTDIR))
 178                                 return 0;
 179
 180                         return -errno;
 181                 }
 182
 183                 if (S_ISREG(st_fd.st_mode) && S_ISREG(st_path.st_mode))
 184                         return
 185                                 st_path.st_dev == st_fd.st_dev &&
 186                                 st_path.st_ino == st_fd.st_ino;
 187                 else if (S_ISCHR(st_fd.st_mode) && S_ISCHR(st_path.st_mode))
 188                         return st_path.st_rdev == st_fd.st_rdev;
 189                 else
 190                         return 0;
 191         }
 192
 193         return 1;
 194 }
 195
 196 static int sd_is_socket_internal(int fd, int type, int listening) {
 197         struct stat st_fd;
 198
 199         assert_return(fd >= 0, -EBADF);
 200         assert_return(type >= 0, -EINVAL);
 201
 202         if (fstat(fd, &st_fd) < 0)
 203                 return -errno;
 204
 205         if (!S_ISSOCK(st_fd.st_mode))
 206                 return 0;
 207
 208         if (type != 0) {
 209                 int other_type = 0;
 210                 socklen_t l = sizeof(other_type);
 211
 212                 if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
 213                         return -errno;
 214
 215                 if (l != sizeof(other_type))
 216                         return -EINVAL;
 217
 218                 if (other_type != type)
 219                         return 0;
 220         }
 221
 222         if (listening >= 0) {
 223                 int accepting = 0;
 224                 socklen_t l = sizeof(accepting);
 225
 226                 if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
 227                         return -errno;
 228
 229                 if (l != sizeof(accepting))
 230                         return -EINVAL;
 231
 232                 if (!accepting != !listening)
 233                         return 0;
 234         }
 235
 236         return 1;
 237 }
 238
 239 _public_ int sd_is_socket(int fd, int family, int type, int listening) {
 240         int r;
 241
 242         assert_return(fd >= 0, -EBADF);
 243         assert_return(family >= 0, -EINVAL);
 244
 245         r = sd_is_socket_internal(fd, type, listening);
 246         if (r <= 0)
 247                 return r;
 248
 249         if (family > 0) {
 250                 union sockaddr_union sockaddr = {};
 251                 socklen_t l = sizeof(sockaddr);
 252
 253                 if (getsockname(fd, &sockaddr.sa, &l) < 0)
 254                         return -errno;
 255
 256                 if (l < sizeof(sa_family_t))
 257                         return -EINVAL;
 258
 259                 return sockaddr.sa.sa_family == family;
 260         }
 261
 262         return 1;
 263 }
 264
 265 _public_ int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
 266         union sockaddr_union sockaddr = {};
 267         socklen_t l = sizeof(sockaddr);
 268         int r;
 269
 270         assert_return(fd >= 0, -EBADF);
 271         assert_return(IN_SET(family, 0, AF_INET, AF_INET6), -EINVAL);
 272
 273         r = sd_is_socket_internal(fd, type, listening);
 274         if (r <= 0)
 275                 return r;
 276
 277         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 278                 return -errno;
 279
 280         if (l < sizeof(sa_family_t))
 281                 return -EINVAL;
 282
 283         if (!IN_SET(sockaddr.sa.sa_family, AF_INET, AF_INET6))
 284                 return 0;
 285
 286         if (family != 0)
 287                 if (sockaddr.sa.sa_family != family)
 288                         return 0;
 289
 290         if (port > 0) {
 291                 unsigned sa_port;
 292
 293                 r = sockaddr_port(&sockaddr.sa, &sa_port);
 294                 if (r < 0)
 295                         return r;
 296
 297                 return port == sa_port;
 298         }
 299
 300         return 1;
 301 }
 302
 303 _public_ int sd_is_socket_sockaddr(int fd, int type, const struct sockaddr* addr, unsigned addr_len, int listening) {
 304         union sockaddr_union sockaddr = {};
 305         socklen_t l = sizeof(sockaddr);
 306         int r;
 307
 308         assert_return(fd >= 0, -EBADF);
 309         assert_return(addr, -EINVAL);
 310         assert_return(addr_len >= sizeof(sa_family_t), -ENOBUFS);
 311         assert_return(IN_SET(addr->sa_family, AF_INET, AF_INET6), -EPFNOSUPPORT);
 312
 313         r = sd_is_socket_internal(fd, type, listening);
 314         if (r <= 0)
 315                 return r;
 316
 317         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 318                 return -errno;
 319
 320         if (l < sizeof(sa_family_t))
 321                 return -EINVAL;
 322
 323         if (sockaddr.sa.sa_family != addr->sa_family)
 324                 return 0;
 325
 326         if (sockaddr.sa.sa_family == AF_INET) {
 327                 const struct sockaddr_in *in = (const struct sockaddr_in *) addr;
 328
 329                 if (l < sizeof(struct sockaddr_in) || addr_len < sizeof(struct sockaddr_in))
 330                         return -EINVAL;
 331
 332                 if (in->sin_port != 0 &&
 333                     sockaddr.in.sin_port != in->sin_port)
 334                         return false;
 335
 336                 return sockaddr.in.sin_addr.s_addr == in->sin_addr.s_addr;
 337
 338         } else {
 339                 const struct sockaddr_in6 *in = (const struct sockaddr_in6 *) addr;
 340
 341                 if (l < sizeof(struct sockaddr_in6) || addr_len < sizeof(struct sockaddr_in6))
 342                         return -EINVAL;
 343
 344                 if (in->sin6_port != 0 &&
 345                     sockaddr.in6.sin6_port != in->sin6_port)
 346                         return false;
 347
 348                 if (in->sin6_flowinfo != 0 &&
 349                     sockaddr.in6.sin6_flowinfo != in->sin6_flowinfo)
 350                         return false;
 351
 352                 if (in->sin6_scope_id != 0 &&
 353                     sockaddr.in6.sin6_scope_id != in->sin6_scope_id)
 354                         return false;
 355
 356                 return memcmp(sockaddr.in6.sin6_addr.s6_addr, in->sin6_addr.s6_addr,
 357                               sizeof(in->sin6_addr.s6_addr)) == 0;
 358         }
 359 }
 360
 361 _public_ int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
 362         union sockaddr_union sockaddr = {};
 363         socklen_t l = sizeof(sockaddr);
 364         int r;
 365
 366         assert_return(fd >= 0, -EBADF);
 367
 368         r = sd_is_socket_internal(fd, type, listening);
 369         if (r <= 0)
 370                 return r;
 371
 372         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 373                 return -errno;
 374
 375         if (l < sizeof(sa_family_t))
 376                 return -EINVAL;
 377
 378         if (sockaddr.sa.sa_family != AF_UNIX)
 379                 return 0;
 380
 381         if (path) {
 382                 if (length == 0)
 383                         length = strlen(path);
 384
 385                 if (length == 0)
 386                         /* Unnamed socket */
 387                         return l == offsetof(struct sockaddr_un, sun_path);
 388
 389                 if (path[0])
 390                         /* Normal path socket */
 391                         return
 392                                 (l >= offsetof(struct sockaddr_un, sun_path) + length + 1) &&
 393                                 memcmp(path, sockaddr.un.sun_path, length+1) == 0;
 394                 else
 395                         /* Abstract namespace socket */
 396                         return
 397                                 (l == offsetof(struct sockaddr_un, sun_path) + length) &&
 398                                 memcmp(path, sockaddr.un.sun_path, length) == 0;
 399         }
 400
 401         return 1;
 402 }
 403
 404 _public_ int sd_is_mq(int fd, const char *path) {
 405         struct mq_attr attr;
 406
 407         /* Check that the fd is valid */
 408         assert_return(fcntl(fd, F_GETFD) >= 0, -errno);
 409
 410         if (mq_getattr(fd, &attr) < 0) {
 411                 if (errno == EBADF)
 412                         /* A non-mq fd (or an invalid one, but we ruled that out above) */
 413                         return 0;
 414                 return -errno;
 415         }
 416
 417         if (path) {
 418                 char fpath[PATH_MAX];
 419                 struct stat a, b;
 420
 421                 assert_return(path_is_absolute(path), -EINVAL);
 422
 423                 if (fstat(fd, &a) < 0)
 424                         return -errno;
 425
 426                 strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
 427                 fpath[sizeof(fpath)-1] = 0;
 428
 429                 if (stat(fpath, &b) < 0)
 430                         return -errno;
 431
 432                 if (a.st_dev != b.st_dev ||
 433                     a.st_ino != b.st_ino)
 434                         return 0;
 435         }
 436
 437         return 1;
 438 }
 439
 440 _public_ int sd_pid_notify_with_fds(
 441                 pid_t pid,
 442                 int unset_environment,
 443                 const char *state,
 444                 const int *fds,
 445                 unsigned n_fds) {
 446
 447         union sockaddr_union sockaddr = {};
 448         struct iovec iovec;
 449         struct msghdr msghdr = {
 450                 .msg_iov = &iovec,
 451                 .msg_iovlen = 1,
 452                 .msg_name = &sockaddr,
 453         };
 454         _cleanup_close_ int fd = -1;
 455         struct cmsghdr *cmsg = NULL;
 456         const char *e;
 457         bool send_ucred;
 458         int r, salen;
 459
 460         if (!state) {
 461                 r = -EINVAL;
 462                 goto finish;
 463         }
 464
 465         if (n_fds > 0 && !fds) {
 466                 r = -EINVAL;
 467                 goto finish;
 468         }
 469
 470         e = getenv("NOTIFY_SOCKET");
 471         if (!e)
 472                 return 0;
 473
 474         salen = sockaddr_un_set_path(&sockaddr.un, e);
 475         if (salen < 0) {
 476                 r = salen;
 477                 goto finish;
 478         }
 479
 480         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
 481         if (fd < 0) {
 482                 r = -errno;
 483                 goto finish;
 484         }
 485
 486         (void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
 487
 488         iovec = IOVEC_MAKE_STRING(state);
 489         msghdr.msg_namelen = salen;
 490
 491         send_ucred =
 492                 (pid != 0 && pid != getpid_cached()) ||
 493                 getuid() != geteuid() ||
 494                 getgid() != getegid();
 495
 496         if (n_fds > 0 || send_ucred) {
 497                 /* CMSG_SPACE(0) may return value different than zero, which results in miscalculated controllen. */
 498                 msghdr.msg_controllen =
 499                         (n_fds > 0 ? CMSG_SPACE(sizeof(int) * n_fds) : 0) +
 500                         (send_ucred ? CMSG_SPACE(sizeof(struct ucred)) : 0);
 501
 502                 msghdr.msg_control = alloca0(msghdr.msg_controllen);
 503
 504                 cmsg = CMSG_FIRSTHDR(&msghdr);
 505                 if (n_fds > 0) {
 506                         cmsg->cmsg_level = SOL_SOCKET;
 507                         cmsg->cmsg_type = SCM_RIGHTS;
 508                         cmsg->cmsg_len = CMSG_LEN(sizeof(int) * n_fds);
 509
 510                         memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * n_fds);
 511
 512                         if (send_ucred)
 513                                 assert_se(cmsg = CMSG_NXTHDR(&msghdr, cmsg));
 514                 }
 515
 516                 if (send_ucred) {
 517                         struct ucred *ucred;
 518
 519                         cmsg->cmsg_level = SOL_SOCKET;
 520                         cmsg->cmsg_type = SCM_CREDENTIALS;
 521                         cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
 522
 523                         ucred = (struct ucred*) CMSG_DATA(cmsg);
 524                         ucred->pid = pid != 0 ? pid : getpid_cached();
 525                         ucred->uid = getuid();
 526                         ucred->gid = getgid();
 527                 }
 528         }
 529
 530         /* First try with fake ucred data, as requested */
 531         if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 532                 r = 1;
 533                 goto finish;
 534         }
 535
 536         /* If that failed, try with our own ucred instead */
 537         if (send_ucred) {
 538                 msghdr.msg_controllen -= CMSG_SPACE(sizeof(struct ucred));
 539                 if (msghdr.msg_controllen == 0)
 540                         msghdr.msg_control = NULL;
 541
 542                 if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 543                         r = 1;
 544                         goto finish;
 545                 }
 546         }
 547
 548         r = -errno;
 549
 550 finish:
 551         if (unset_environment)
 552                 unsetenv("NOTIFY_SOCKET");
 553
 554         return r;
 555 }
 556
 557 _public_ int sd_pid_notify(pid_t pid, int unset_environment, const char *state) {
 558         return sd_pid_notify_with_fds(pid, unset_environment, state, NULL, 0);
 559 }
 560
 561 _public_ int sd_notify(int unset_environment, const char *state) {
 562         return sd_pid_notify_with_fds(0, unset_environment, state, NULL, 0);
 563 }
 564
 565 _public_ int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) {
 566         _cleanup_free_ char *p = NULL;
 567         int r;
 568
 569         if (format) {
 570                 va_list ap;
 571
 572                 va_start(ap, format);
 573                 r = vasprintf(&p, format, ap);
 574                 va_end(ap);
 575
 576                 if (r < 0 || !p)
 577                         return -ENOMEM;
 578         }
 579
 580         return sd_pid_notify(pid, unset_environment, p);
 581 }
 582
 583 _public_ int sd_notifyf(int unset_environment, const char *format, ...) {
 584         _cleanup_free_ char *p = NULL;
 585         int r;
 586
 587         if (format) {
 588                 va_list ap;
 589
 590                 va_start(ap, format);
 591                 r = vasprintf(&p, format, ap);
 592                 va_end(ap);
 593
 594                 if (r < 0 || !p)
 595                         return -ENOMEM;
 596         }
 597
 598         return sd_pid_notify(0, unset_environment, p);
 599 }
 600
 601 _public_ int sd_booted(void) {
 602         /* We test whether the runtime unit file directory has been
 603          * created. This takes place in mount-setup.c, so is
 604          * guaranteed to happen very early during boot. */
 605
 606         if (laccess("/run/systemd/system/", F_OK) >= 0)
 607                 return true;
 608
 609         if (errno == ENOENT)
 610                 return false;
 611
 612         return -errno;
 613 }
 614
 615 _public_ int sd_watchdog_enabled(int unset_environment, uint64_t *usec) {
 616         const char *s, *p = ""; /* p is set to dummy value to do unsetting */
 617         uint64_t u;
 618         int r = 0;
 619
 620         s = getenv("WATCHDOG_USEC");
 621         if (!s)
 622                 goto finish;
 623
 624         r = safe_atou64(s, &u);
 625         if (r < 0)
 626                 goto finish;
 627         if (u <= 0 || u >= USEC_INFINITY) {
 628                 r = -EINVAL;
 629                 goto finish;
 630         }
 631
 632         p = getenv("WATCHDOG_PID");
 633         if (p) {
 634                 pid_t pid;
 635
 636                 r = parse_pid(p, &pid);
 637                 if (r < 0)
 638                         goto finish;
 639
 640                 /* Is this for us? */
 641                 if (getpid_cached() != pid) {
 642                         r = 0;
 643                         goto finish;
 644                 }
 645         }
 646
 647         if (usec)
 648                 *usec = u;
 649
 650         r = 1;
 651
 652 finish:
 653         if (unset_environment && s)
 654                 unsetenv("WATCHDOG_USEC");
 655         if (unset_environment && p)
 656                 unsetenv("WATCHDOG_PID");
 657
 658         return r;
 659 }