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