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 <string.h>
  12 #include <sys/socket.h>
  13 #include <sys/stat.h>
  14 #include <sys/un.h>
  15 #include <unistd.h>
  16
  17 #include "sd-daemon.h"
  18
  19 #include "alloc-util.h"
  20 #include "fd-util.h"
  21 #include "fs-util.h"
  22 #include "io-util.h"
  23 #include "parse-util.h"
  24 #include "path-util.h"
  25 #include "process-util.h"
  26 #include "socket-util.h"
  27 #include "strv.h"
  28 #include "util.h"
  29
  30 #define SNDBUF_SIZE (8*1024*1024)
  31
  32 static void unsetenv_all(bool unset_environment) {
  33
  34         if (!unset_environment)
  35                 return;
  36
  37         unsetenv("LISTEN_PID");
  38         unsetenv("LISTEN_FDS");
  39         unsetenv("LISTEN_FDNAMES");
  40 }
  41
  42 _public_ int sd_listen_fds(int unset_environment) {
  43         const char *e;
  44         int n, r, fd;
  45         pid_t pid;
  46
  47         e = getenv("LISTEN_PID");
  48         if (!e) {
  49                 r = 0;
  50                 goto finish;
  51         }
  52
  53         r = parse_pid(e, &pid);
  54         if (r < 0)
  55                 goto finish;
  56
  57         /* Is this for us? */
  58         if (getpid_cached() != pid) {
  59                 r = 0;
  60                 goto finish;
  61         }
  62
  63         e = getenv("LISTEN_FDS");
  64         if (!e) {
  65                 r = 0;
  66                 goto finish;
  67         }
  68
  69         r = safe_atoi(e, &n);
  70         if (r < 0)
  71                 goto finish;
  72
  73         assert_cc(SD_LISTEN_FDS_START < INT_MAX);
  74         if (n <= 0 || n > INT_MAX - SD_LISTEN_FDS_START) {
  75                 r = -EINVAL;
  76                 goto finish;
  77         }
  78
  79         for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd ++) {
  80                 r = fd_cloexec(fd, true);
  81                 if (r < 0)
  82                         goto finish;
  83         }
  84
  85         r = n;
  86
  87 finish:
  88         unsetenv_all(unset_environment);
  89         return r;
  90 }
  91
  92 _public_ int sd_listen_fds_with_names(int unset_environment, char ***names) {
  93         _cleanup_strv_free_ char **l = NULL;
  94         bool have_names;
  95         int n_names = 0, n_fds;
  96         const char *e;
  97         int r;
  98
  99         if (!names)
 100                 return sd_listen_fds(unset_environment);
 101
 102         e = getenv("LISTEN_FDNAMES");
 103         if (e) {
 104                 n_names = strv_split_extract(&l, e, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
 105                 if (n_names < 0) {
 106                         unsetenv_all(unset_environment);
 107                         return n_names;
 108                 }
 109
 110                 have_names = true;
 111         } else
 112                 have_names = false;
 113
 114         n_fds = sd_listen_fds(unset_environment);
 115         if (n_fds <= 0)
 116                 return n_fds;
 117
 118         if (have_names) {
 119                 if (n_names != n_fds)
 120                         return -EINVAL;
 121         } else {
 122                 r = strv_extend_n(&l, "unknown", n_fds);
 123                 if (r < 0)
 124                         return r;
 125         }
 126
 127         *names = TAKE_PTR(l);
 128
 129         return n_fds;
 130 }
 131
 132 _public_ int sd_is_fifo(int fd, const char *path) {
 133         struct stat st_fd;
 134
 135         assert_return(fd >= 0, -EBADF);
 136
 137         if (fstat(fd, &st_fd) < 0)
 138                 return -errno;
 139
 140         if (!S_ISFIFO(st_fd.st_mode))
 141                 return 0;
 142
 143         if (path) {
 144                 struct stat st_path;
 145
 146                 if (stat(path, &st_path) < 0) {
 147
 148                         if (IN_SET(errno, ENOENT, ENOTDIR))
 149                                 return 0;
 150
 151                         return -errno;
 152                 }
 153
 154                 return
 155                         st_path.st_dev == st_fd.st_dev &&
 156                         st_path.st_ino == st_fd.st_ino;
 157         }
 158
 159         return 1;
 160 }
 161
 162 _public_ int sd_is_special(int fd, const char *path) {
 163         struct stat st_fd;
 164
 165         assert_return(fd >= 0, -EBADF);
 166
 167         if (fstat(fd, &st_fd) < 0)
 168                 return -errno;
 169
 170         if (!S_ISREG(st_fd.st_mode) && !S_ISCHR(st_fd.st_mode))
 171                 return 0;
 172
 173         if (path) {
 174                 struct stat st_path;
 175
 176                 if (stat(path, &st_path) < 0) {
 177
 178                         if (IN_SET(errno, ENOENT, ENOTDIR))
 179                                 return 0;
 180
 181                         return -errno;
 182                 }
 183
 184                 if (S_ISREG(st_fd.st_mode) && S_ISREG(st_path.st_mode))
 185                         return
 186                                 st_path.st_dev == st_fd.st_dev &&
 187                                 st_path.st_ino == st_fd.st_ino;
 188                 else if (S_ISCHR(st_fd.st_mode) && S_ISCHR(st_path.st_mode))
 189                         return st_path.st_rdev == st_fd.st_rdev;
 190                 else
 191                         return 0;
 192         }
 193
 194         return 1;
 195 }
 196
 197 static int sd_is_socket_internal(int fd, int type, int listening) {
 198         struct stat st_fd;
 199
 200         assert_return(fd >= 0, -EBADF);
 201         assert_return(type >= 0, -EINVAL);
 202
 203         if (fstat(fd, &st_fd) < 0)
 204                 return -errno;
 205
 206         if (!S_ISSOCK(st_fd.st_mode))
 207                 return 0;
 208
 209         if (type != 0) {
 210                 int other_type = 0;
 211                 socklen_t l = sizeof(other_type);
 212
 213                 if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
 214                         return -errno;
 215
 216                 if (l != sizeof(other_type))
 217                         return -EINVAL;
 218
 219                 if (other_type != type)
 220                         return 0;
 221         }
 222
 223         if (listening >= 0) {
 224                 int accepting = 0;
 225                 socklen_t l = sizeof(accepting);
 226
 227                 if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
 228                         return -errno;
 229
 230                 if (l != sizeof(accepting))
 231                         return -EINVAL;
 232
 233                 if (!accepting != !listening)
 234                         return 0;
 235         }
 236
 237         return 1;
 238 }
 239
 240 _public_ int sd_is_socket(int fd, int family, int type, int listening) {
 241         int r;
 242
 243         assert_return(fd >= 0, -EBADF);
 244         assert_return(family >= 0, -EINVAL);
 245
 246         r = sd_is_socket_internal(fd, type, listening);
 247         if (r <= 0)
 248                 return r;
 249
 250         if (family > 0) {
 251                 union sockaddr_union sockaddr = {};
 252                 socklen_t l = sizeof(sockaddr);
 253
 254                 if (getsockname(fd, &sockaddr.sa, &l) < 0)
 255                         return -errno;
 256
 257                 if (l < sizeof(sa_family_t))
 258                         return -EINVAL;
 259
 260                 return sockaddr.sa.sa_family == family;
 261         }
 262
 263         return 1;
 264 }
 265
 266 _public_ int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
 267         union sockaddr_union sockaddr = {};
 268         socklen_t l = sizeof(sockaddr);
 269         int r;
 270
 271         assert_return(fd >= 0, -EBADF);
 272         assert_return(IN_SET(family, 0, AF_INET, AF_INET6), -EINVAL);
 273
 274         r = sd_is_socket_internal(fd, type, listening);
 275         if (r <= 0)
 276                 return r;
 277
 278         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 279                 return -errno;
 280
 281         if (l < sizeof(sa_family_t))
 282                 return -EINVAL;
 283
 284         if (!IN_SET(sockaddr.sa.sa_family, AF_INET, AF_INET6))
 285                 return 0;
 286
 287         if (family != 0)
 288                 if (sockaddr.sa.sa_family != family)
 289                         return 0;
 290
 291         if (port > 0) {
 292                 unsigned sa_port;
 293
 294                 r = sockaddr_port(&sockaddr.sa, &sa_port);
 295                 if (r < 0)
 296                         return r;
 297
 298                 return port == sa_port;
 299         }
 300
 301         return 1;
 302 }
 303
 304 _public_ int sd_is_socket_sockaddr(int fd, int type, const struct sockaddr* addr, unsigned addr_len, int listening) {
 305         union sockaddr_union sockaddr = {};
 306         socklen_t l = sizeof(sockaddr);
 307         int r;
 308
 309         assert_return(fd >= 0, -EBADF);
 310         assert_return(addr, -EINVAL);
 311         assert_return(addr_len >= sizeof(sa_family_t), -ENOBUFS);
 312         assert_return(IN_SET(addr->sa_family, AF_INET, AF_INET6), -EPFNOSUPPORT);
 313
 314         r = sd_is_socket_internal(fd, type, listening);
 315         if (r <= 0)
 316                 return r;
 317
 318         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 319                 return -errno;
 320
 321         if (l < sizeof(sa_family_t))
 322                 return -EINVAL;
 323
 324         if (sockaddr.sa.sa_family != addr->sa_family)
 325                 return 0;
 326
 327         if (sockaddr.sa.sa_family == AF_INET) {
 328                 const struct sockaddr_in *in = (const struct sockaddr_in *) addr;
 329
 330                 if (l < sizeof(struct sockaddr_in) || addr_len < sizeof(struct sockaddr_in))
 331                         return -EINVAL;
 332
 333                 if (in->sin_port != 0 &&
 334                     sockaddr.in.sin_port != in->sin_port)
 335                         return false;
 336
 337                 return sockaddr.in.sin_addr.s_addr == in->sin_addr.s_addr;
 338
 339         } else {
 340                 const struct sockaddr_in6 *in = (const struct sockaddr_in6 *) addr;
 341
 342                 if (l < sizeof(struct sockaddr_in6) || addr_len < sizeof(struct sockaddr_in6))
 343                         return -EINVAL;
 344
 345                 if (in->sin6_port != 0 &&
 346                     sockaddr.in6.sin6_port != in->sin6_port)
 347                         return false;
 348
 349                 if (in->sin6_flowinfo != 0 &&
 350                     sockaddr.in6.sin6_flowinfo != in->sin6_flowinfo)
 351                         return false;
 352
 353                 if (in->sin6_scope_id != 0 &&
 354                     sockaddr.in6.sin6_scope_id != in->sin6_scope_id)
 355                         return false;
 356
 357                 return memcmp(sockaddr.in6.sin6_addr.s6_addr, in->sin6_addr.s6_addr,
 358                               sizeof(in->sin6_addr.s6_addr)) == 0;
 359         }
 360 }
 361
 362 _public_ int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
 363         union sockaddr_union sockaddr = {};
 364         socklen_t l = sizeof(sockaddr);
 365         int r;
 366
 367         assert_return(fd >= 0, -EBADF);
 368
 369         r = sd_is_socket_internal(fd, type, listening);
 370         if (r <= 0)
 371                 return r;
 372
 373         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 374                 return -errno;
 375
 376         if (l < sizeof(sa_family_t))
 377                 return -EINVAL;
 378
 379         if (sockaddr.sa.sa_family != AF_UNIX)
 380                 return 0;
 381
 382         if (path) {
 383                 if (length == 0)
 384                         length = strlen(path);
 385
 386                 if (length == 0)
 387                         /* Unnamed socket */
 388                         return l == offsetof(struct sockaddr_un, sun_path);
 389
 390                 if (path[0])
 391                         /* Normal path socket */
 392                         return
 393                                 (l >= offsetof(struct sockaddr_un, sun_path) + length + 1) &&
 394                                 memcmp(path, sockaddr.un.sun_path, length+1) == 0;
 395                 else
 396                         /* Abstract namespace socket */
 397                         return
 398                                 (l == offsetof(struct sockaddr_un, sun_path) + length) &&
 399                                 memcmp(path, sockaddr.un.sun_path, length) == 0;
 400         }
 401
 402         return 1;
 403 }
 404
 405 _public_ int sd_is_mq(int fd, const char *path) {
 406         struct mq_attr attr;
 407
 408         /* Check that the fd is valid */
 409         assert_return(fcntl(fd, F_GETFD) >= 0, -errno);
 410
 411         if (mq_getattr(fd, &attr) < 0) {
 412                 if (errno == EBADF)
 413                         /* A non-mq fd (or an invalid one, but we ruled that out above) */
 414                         return 0;
 415                 return -errno;
 416         }
 417
 418         if (path) {
 419                 char fpath[PATH_MAX];
 420                 struct stat a, b;
 421
 422                 assert_return(path_is_absolute(path), -EINVAL);
 423
 424                 if (fstat(fd, &a) < 0)
 425                         return -errno;
 426
 427                 strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
 428                 fpath[sizeof(fpath)-1] = 0;
 429
 430                 if (stat(fpath, &b) < 0)
 431                         return -errno;
 432
 433                 if (a.st_dev != b.st_dev ||
 434                     a.st_ino != b.st_ino)
 435                         return 0;
 436         }
 437
 438         return 1;
 439 }
 440
 441 _public_ int sd_pid_notify_with_fds(
 442                 pid_t pid,
 443                 int unset_environment,
 444                 const char *state,
 445                 const int *fds,
 446                 unsigned n_fds) {
 447
 448         union sockaddr_union sockaddr = {};
 449         struct iovec iovec;
 450         struct msghdr msghdr = {
 451                 .msg_iov = &iovec,
 452                 .msg_iovlen = 1,
 453                 .msg_name = &sockaddr,
 454         };
 455         _cleanup_close_ int fd = -1;
 456         struct cmsghdr *cmsg = NULL;
 457         const char *e;
 458         bool send_ucred;
 459         int r, salen;
 460
 461         if (!state) {
 462                 r = -EINVAL;
 463                 goto finish;
 464         }
 465
 466         if (n_fds > 0 && !fds) {
 467                 r = -EINVAL;
 468                 goto finish;
 469         }
 470
 471         e = getenv("NOTIFY_SOCKET");
 472         if (!e)
 473                 return 0;
 474
 475         salen = sockaddr_un_set_path(&sockaddr.un, e);
 476         if (salen < 0) {
 477                 r = salen;
 478                 goto finish;
 479         }
 480
 481         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
 482         if (fd < 0) {
 483                 r = -errno;
 484                 goto finish;
 485         }
 486
 487         (void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
 488
 489         iovec = IOVEC_MAKE_STRING(state);
 490         msghdr.msg_namelen = salen;
 491
 492         send_ucred =
 493                 (pid != 0 && pid != getpid_cached()) ||
 494                 getuid() != geteuid() ||
 495                 getgid() != getegid();
 496
 497         if (n_fds > 0 || send_ucred) {
 498                 /* CMSG_SPACE(0) may return value different than zero, which results in miscalculated controllen. */
 499                 msghdr.msg_controllen =
 500                         (n_fds > 0 ? CMSG_SPACE(sizeof(int) * n_fds) : 0) +
 501                         (send_ucred ? CMSG_SPACE(sizeof(struct ucred)) : 0);
 502
 503                 msghdr.msg_control = alloca0(msghdr.msg_controllen);
 504
 505                 cmsg = CMSG_FIRSTHDR(&msghdr);
 506                 if (n_fds > 0) {
 507                         cmsg->cmsg_level = SOL_SOCKET;
 508                         cmsg->cmsg_type = SCM_RIGHTS;
 509                         cmsg->cmsg_len = CMSG_LEN(sizeof(int) * n_fds);
 510
 511                         memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * n_fds);
 512
 513                         if (send_ucred)
 514                                 assert_se(cmsg = CMSG_NXTHDR(&msghdr, cmsg));
 515                 }
 516
 517                 if (send_ucred) {
 518                         struct ucred *ucred;
 519
 520                         cmsg->cmsg_level = SOL_SOCKET;
 521                         cmsg->cmsg_type = SCM_CREDENTIALS;
 522                         cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
 523
 524                         ucred = (struct ucred*) CMSG_DATA(cmsg);
 525                         ucred->pid = pid != 0 ? pid : getpid_cached();
 526                         ucred->uid = getuid();
 527                         ucred->gid = getgid();
 528                 }
 529         }
 530
 531         /* First try with fake ucred data, as requested */
 532         if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 533                 r = 1;
 534                 goto finish;
 535         }
 536
 537         /* If that failed, try with our own ucred instead */
 538         if (send_ucred) {
 539                 msghdr.msg_controllen -= CMSG_SPACE(sizeof(struct ucred));
 540                 if (msghdr.msg_controllen == 0)
 541                         msghdr.msg_control = NULL;
 542
 543                 if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 544                         r = 1;
 545                         goto finish;
 546                 }
 547         }
 548
 549         r = -errno;
 550
 551 finish:
 552         if (unset_environment)
 553                 unsetenv("NOTIFY_SOCKET");
 554
 555         return r;
 556 }
 557
 558 _public_ int sd_pid_notify(pid_t pid, int unset_environment, const char *state) {
 559         return sd_pid_notify_with_fds(pid, unset_environment, state, NULL, 0);
 560 }
 561
 562 _public_ int sd_notify(int unset_environment, const char *state) {
 563         return sd_pid_notify_with_fds(0, unset_environment, state, NULL, 0);
 564 }
 565
 566 _public_ int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) {
 567         _cleanup_free_ char *p = NULL;
 568         int r;
 569
 570         if (format) {
 571                 va_list ap;
 572
 573                 va_start(ap, format);
 574                 r = vasprintf(&p, format, ap);
 575                 va_end(ap);
 576
 577                 if (r < 0 || !p)
 578                         return -ENOMEM;
 579         }
 580
 581         return sd_pid_notify(pid, unset_environment, p);
 582 }
 583
 584 _public_ int sd_notifyf(int unset_environment, const char *format, ...) {
 585         _cleanup_free_ char *p = NULL;
 586         int r;
 587
 588         if (format) {
 589                 va_list ap;
 590
 591                 va_start(ap, format);
 592                 r = vasprintf(&p, format, ap);
 593                 va_end(ap);
 594
 595                 if (r < 0 || !p)
 596                         return -ENOMEM;
 597         }
 598
 599         return sd_pid_notify(0, unset_environment, p);
 600 }
 601
 602 _public_ int sd_booted(void) {
 603         /* We test whether the runtime unit file directory has been
 604          * created. This takes place in mount-setup.c, so is
 605          * guaranteed to happen very early during boot. */
 606
 607         if (laccess("/run/systemd/system/", F_OK) >= 0)
 608                 return true;
 609
 610         if (errno == ENOENT)
 611                 return false;
 612
 613         return -errno;
 614 }
 615
 616 _public_ int sd_watchdog_enabled(int unset_environment, uint64_t *usec) {
 617         const char *s, *p = ""; /* p is set to dummy value to do unsetting */
 618         uint64_t u;
 619         int r = 0;
 620
 621         s = getenv("WATCHDOG_USEC");
 622         if (!s)
 623                 goto finish;
 624
 625         r = safe_atou64(s, &u);
 626         if (r < 0)
 627                 goto finish;
 628         if (u <= 0 || u >= USEC_INFINITY) {
 629                 r = -EINVAL;
 630                 goto finish;
 631         }
 632
 633         p = getenv("WATCHDOG_PID");
 634         if (p) {
 635                 pid_t pid;
 636
 637                 r = parse_pid(p, &pid);
 638                 if (r < 0)
 639                         goto finish;
 640
 641                 /* Is this for us? */
 642                 if (getpid_cached() != pid) {
 643                         r = 0;
 644                         goto finish;
 645                 }
 646         }
 647
 648         if (usec)
 649                 *usec = u;
 650
 651         r = 1;
 652
 653 finish:
 654         if (unset_environment && s)
 655                 unsetenv("WATCHDOG_USEC");
 656         if (unset_environment && p)
 657                 unsetenv("WATCHDOG_PID");
 658
 659         return r;
 660 }