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

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2010 Lennart Poettering
   4 ***/
   5
   6 #include <errno.h>
   7 #include <limits.h>
   8 #include <mqueue.h>
   9 #include <netinet/in.h>
  10 #include <stdarg.h>
  11 #include <stddef.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/socket.h>
  16 #include <sys/stat.h>
  17 #include <sys/un.h>
  18 #include <unistd.h>
  19
  20 #include "sd-daemon.h"
  21
  22 #include "alloc-util.h"
  23 #include "fd-util.h"
  24 #include "fs-util.h"
  25 #include "parse-util.h"
  26 #include "path-util.h"
  27 #include "process-util.h"
  28 #include "socket-util.h"
  29 #include "strv.h"
  30 #include "util.h"
  31
  32 #define SNDBUF_SIZE (8*1024*1024)
  33
  34 static void unsetenv_all(bool unset_environment) {
  35
  36         if (!unset_environment)
  37                 return;
  38
  39         unsetenv("LISTEN_PID");
  40         unsetenv("LISTEN_FDS");
  41         unsetenv("LISTEN_FDNAMES");
  42 }
  43
  44 _public_ int sd_listen_fds(int unset_environment) {
  45         const char *e;
  46         int n, r, fd;
  47         pid_t pid;
  48
  49         e = getenv("LISTEN_PID");
  50         if (!e) {
  51                 r = 0;
  52                 goto finish;
  53         }
  54
  55         r = parse_pid(e, &pid);
  56         if (r < 0)
  57                 goto finish;
  58
  59         /* Is this for us? */
  60         if (getpid_cached() != pid) {
  61                 r = 0;
  62                 goto finish;
  63         }
  64
  65         e = getenv("LISTEN_FDS");
  66         if (!e) {
  67                 r = 0;
  68                 goto finish;
  69         }
  70
  71         r = safe_atoi(e, &n);
  72         if (r < 0)
  73                 goto finish;
  74
  75         assert_cc(SD_LISTEN_FDS_START < INT_MAX);
  76         if (n <= 0 || n > INT_MAX - SD_LISTEN_FDS_START) {
  77                 r = -EINVAL;
  78                 goto finish;
  79         }
  80
  81         for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd ++) {
  82                 r = fd_cloexec(fd, true);
  83                 if (r < 0)
  84                         goto finish;
  85         }
  86
  87         r = n;
  88
  89 finish:
  90         unsetenv_all(unset_environment);
  91         return r;
  92 }
  93
  94 _public_ int sd_listen_fds_with_names(int unset_environment, char ***names) {
  95         _cleanup_strv_free_ char **l = NULL;
  96         bool have_names;
  97         int n_names = 0, n_fds;
  98         const char *e;
  99         int r;
 100
 101         if (!names)
 102                 return sd_listen_fds(unset_environment);
 103
 104         e = getenv("LISTEN_FDNAMES");
 105         if (e) {
 106                 n_names = strv_split_extract(&l, e, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
 107                 if (n_names < 0) {
 108                         unsetenv_all(unset_environment);
 109                         return n_names;
 110                 }
 111
 112                 have_names = true;
 113         } else
 114                 have_names = false;
 115
 116         n_fds = sd_listen_fds(unset_environment);
 117         if (n_fds <= 0)
 118                 return n_fds;
 119
 120         if (have_names) {
 121                 if (n_names != n_fds)
 122                         return -EINVAL;
 123         } else {
 124                 r = strv_extend_n(&l, "unknown", n_fds);
 125                 if (r < 0)
 126                         return r;
 127         }
 128
 129         *names = TAKE_PTR(l);
 130
 131         return n_fds;
 132 }
 133
 134 _public_ int sd_is_fifo(int fd, const char *path) {
 135         struct stat st_fd;
 136
 137         assert_return(fd >= 0, -EBADF);
 138
 139         if (fstat(fd, &st_fd) < 0)
 140                 return -errno;
 141
 142         if (!S_ISFIFO(st_fd.st_mode))
 143                 return 0;
 144
 145         if (path) {
 146                 struct stat st_path;
 147
 148                 if (stat(path, &st_path) < 0) {
 149
 150                         if (IN_SET(errno, ENOENT, ENOTDIR))
 151                                 return 0;
 152
 153                         return -errno;
 154                 }
 155
 156                 return
 157                         st_path.st_dev == st_fd.st_dev &&
 158                         st_path.st_ino == st_fd.st_ino;
 159         }
 160
 161         return 1;
 162 }
 163
 164 _public_ int sd_is_special(int fd, const char *path) {
 165         struct stat st_fd;
 166
 167         assert_return(fd >= 0, -EBADF);
 168
 169         if (fstat(fd, &st_fd) < 0)
 170                 return -errno;
 171
 172         if (!S_ISREG(st_fd.st_mode) && !S_ISCHR(st_fd.st_mode))
 173                 return 0;
 174
 175         if (path) {
 176                 struct stat st_path;
 177
 178                 if (stat(path, &st_path) < 0) {
 179
 180                         if (IN_SET(errno, ENOENT, ENOTDIR))
 181                                 return 0;
 182
 183                         return -errno;
 184                 }
 185
 186                 if (S_ISREG(st_fd.st_mode) && S_ISREG(st_path.st_mode))
 187                         return
 188                                 st_path.st_dev == st_fd.st_dev &&
 189                                 st_path.st_ino == st_fd.st_ino;
 190                 else if (S_ISCHR(st_fd.st_mode) && S_ISCHR(st_path.st_mode))
 191                         return st_path.st_rdev == st_fd.st_rdev;
 192                 else
 193                         return 0;
 194         }
 195
 196         return 1;
 197 }
 198
 199 static int sd_is_socket_internal(int fd, int type, int listening) {
 200         struct stat st_fd;
 201
 202         assert_return(fd >= 0, -EBADF);
 203         assert_return(type >= 0, -EINVAL);
 204
 205         if (fstat(fd, &st_fd) < 0)
 206                 return -errno;
 207
 208         if (!S_ISSOCK(st_fd.st_mode))
 209                 return 0;
 210
 211         if (type != 0) {
 212                 int other_type = 0;
 213                 socklen_t l = sizeof(other_type);
 214
 215                 if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
 216                         return -errno;
 217
 218                 if (l != sizeof(other_type))
 219                         return -EINVAL;
 220
 221                 if (other_type != type)
 222                         return 0;
 223         }
 224
 225         if (listening >= 0) {
 226                 int accepting = 0;
 227                 socklen_t l = sizeof(accepting);
 228
 229                 if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
 230                         return -errno;
 231
 232                 if (l != sizeof(accepting))
 233                         return -EINVAL;
 234
 235                 if (!accepting != !listening)
 236                         return 0;
 237         }
 238
 239         return 1;
 240 }
 241
 242 _public_ int sd_is_socket(int fd, int family, int type, int listening) {
 243         int r;
 244
 245         assert_return(fd >= 0, -EBADF);
 246         assert_return(family >= 0, -EINVAL);
 247
 248         r = sd_is_socket_internal(fd, type, listening);
 249         if (r <= 0)
 250                 return r;
 251
 252         if (family > 0) {
 253                 union sockaddr_union sockaddr = {};
 254                 socklen_t l = sizeof(sockaddr);
 255
 256                 if (getsockname(fd, &sockaddr.sa, &l) < 0)
 257                         return -errno;
 258
 259                 if (l < sizeof(sa_family_t))
 260                         return -EINVAL;
 261
 262                 return sockaddr.sa.sa_family == family;
 263         }
 264
 265         return 1;
 266 }
 267
 268 _public_ int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
 269         union sockaddr_union sockaddr = {};
 270         socklen_t l = sizeof(sockaddr);
 271         int r;
 272
 273         assert_return(fd >= 0, -EBADF);
 274         assert_return(IN_SET(family, 0, AF_INET, AF_INET6), -EINVAL);
 275
 276         r = sd_is_socket_internal(fd, type, listening);
 277         if (r <= 0)
 278                 return r;
 279
 280         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 281                 return -errno;
 282
 283         if (l < sizeof(sa_family_t))
 284                 return -EINVAL;
 285
 286         if (!IN_SET(sockaddr.sa.sa_family, AF_INET, AF_INET6))
 287                 return 0;
 288
 289         if (family != 0)
 290                 if (sockaddr.sa.sa_family != family)
 291                         return 0;
 292
 293         if (port > 0) {
 294                 unsigned sa_port;
 295
 296                 r = sockaddr_port(&sockaddr.sa, &sa_port);
 297                 if (r < 0)
 298                         return r;
 299
 300                 return port == sa_port;
 301         }
 302
 303         return 1;
 304 }
 305
 306 _public_ int sd_is_socket_sockaddr(int fd, int type, const struct sockaddr* addr, unsigned addr_len, int listening) {
 307         union sockaddr_union sockaddr = {};
 308         socklen_t l = sizeof(sockaddr);
 309         int r;
 310
 311         assert_return(fd >= 0, -EBADF);
 312         assert_return(addr, -EINVAL);
 313         assert_return(addr_len >= sizeof(sa_family_t), -ENOBUFS);
 314         assert_return(IN_SET(addr->sa_family, AF_INET, AF_INET6), -EPFNOSUPPORT);
 315
 316         r = sd_is_socket_internal(fd, type, listening);
 317         if (r <= 0)
 318                 return r;
 319
 320         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 321                 return -errno;
 322
 323         if (l < sizeof(sa_family_t))
 324                 return -EINVAL;
 325
 326         if (sockaddr.sa.sa_family != addr->sa_family)
 327                 return 0;
 328
 329         if (sockaddr.sa.sa_family == AF_INET) {
 330                 const struct sockaddr_in *in = (const struct sockaddr_in *) addr;
 331
 332                 if (l < sizeof(struct sockaddr_in) || addr_len < sizeof(struct sockaddr_in))
 333                         return -EINVAL;
 334
 335                 if (in->sin_port != 0 &&
 336                     sockaddr.in.sin_port != in->sin_port)
 337                         return false;
 338
 339                 return sockaddr.in.sin_addr.s_addr == in->sin_addr.s_addr;
 340
 341         } else {
 342                 const struct sockaddr_in6 *in = (const struct sockaddr_in6 *) addr;
 343
 344                 if (l < sizeof(struct sockaddr_in6) || addr_len < sizeof(struct sockaddr_in6))
 345                         return -EINVAL;
 346
 347                 if (in->sin6_port != 0 &&
 348                     sockaddr.in6.sin6_port != in->sin6_port)
 349                         return false;
 350
 351                 if (in->sin6_flowinfo != 0 &&
 352                     sockaddr.in6.sin6_flowinfo != in->sin6_flowinfo)
 353                         return false;
 354
 355                 if (in->sin6_scope_id != 0 &&
 356                     sockaddr.in6.sin6_scope_id != in->sin6_scope_id)
 357                         return false;
 358
 359                 return memcmp(sockaddr.in6.sin6_addr.s6_addr, in->sin6_addr.s6_addr,
 360                               sizeof(in->sin6_addr.s6_addr)) == 0;
 361         }
 362 }
 363
 364 _public_ int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
 365         union sockaddr_union sockaddr = {};
 366         socklen_t l = sizeof(sockaddr);
 367         int r;
 368
 369         assert_return(fd >= 0, -EBADF);
 370
 371         r = sd_is_socket_internal(fd, type, listening);
 372         if (r <= 0)
 373                 return r;
 374
 375         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 376                 return -errno;
 377
 378         if (l < sizeof(sa_family_t))
 379                 return -EINVAL;
 380
 381         if (sockaddr.sa.sa_family != AF_UNIX)
 382                 return 0;
 383
 384         if (path) {
 385                 if (length == 0)
 386                         length = strlen(path);
 387
 388                 if (length == 0)
 389                         /* Unnamed socket */
 390                         return l == offsetof(struct sockaddr_un, sun_path);
 391
 392                 if (path[0])
 393                         /* Normal path socket */
 394                         return
 395                                 (l >= offsetof(struct sockaddr_un, sun_path) + length + 1) &&
 396                                 memcmp(path, sockaddr.un.sun_path, length+1) == 0;
 397                 else
 398                         /* Abstract namespace socket */
 399                         return
 400                                 (l == offsetof(struct sockaddr_un, sun_path) + length) &&
 401                                 memcmp(path, sockaddr.un.sun_path, length) == 0;
 402         }
 403
 404         return 1;
 405 }
 406
 407 _public_ int sd_is_mq(int fd, const char *path) {
 408         struct mq_attr attr;
 409
 410         /* Check that the fd is valid */
 411         assert_return(fcntl(fd, F_GETFD) >= 0, -errno);
 412
 413         if (mq_getattr(fd, &attr) < 0) {
 414                 if (errno == EBADF)
 415                         /* A non-mq fd (or an invalid one, but we ruled that out above) */
 416                         return 0;
 417                 return -errno;
 418         }
 419
 420         if (path) {
 421                 char fpath[PATH_MAX];
 422                 struct stat a, b;
 423
 424                 assert_return(path_is_absolute(path), -EINVAL);
 425
 426                 if (fstat(fd, &a) < 0)
 427                         return -errno;
 428
 429                 strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
 430                 fpath[sizeof(fpath)-1] = 0;
 431
 432                 if (stat(fpath, &b) < 0)
 433                         return -errno;
 434
 435                 if (a.st_dev != b.st_dev ||
 436                     a.st_ino != b.st_ino)
 437                         return 0;
 438         }
 439
 440         return 1;
 441 }
 442
 443 _public_ int sd_pid_notify_with_fds(
 444                 pid_t pid,
 445                 int unset_environment,
 446                 const char *state,
 447                 const int *fds,
 448                 unsigned n_fds) {
 449
 450         union sockaddr_union sockaddr = {
 451                 .sa.sa_family = AF_UNIX,
 452         };
 453         struct iovec iovec = {
 454                 .iov_base = (char*) state,
 455         };
 456         struct msghdr msghdr = {
 457                 .msg_iov = &iovec,
 458                 .msg_iovlen = 1,
 459                 .msg_name = &sockaddr,
 460         };
 461         _cleanup_close_ int fd = -1;
 462         struct cmsghdr *cmsg = NULL;
 463         const char *e;
 464         bool send_ucred;
 465         int r;
 466
 467         if (!state) {
 468                 r = -EINVAL;
 469                 goto finish;
 470         }
 471
 472         if (n_fds > 0 && !fds) {
 473                 r = -EINVAL;
 474                 goto finish;
 475         }
 476
 477         e = getenv("NOTIFY_SOCKET");
 478         if (!e)
 479                 return 0;
 480
 481         /* Must be an abstract socket, or an absolute path */
 482         if (!IN_SET(e[0], '@', '/') || e[1] == 0) {
 483                 r = -EINVAL;
 484                 goto finish;
 485         }
 486
 487         if (strlen(e) > sizeof(sockaddr.un.sun_path)) {
 488                 r = -EINVAL;
 489                 goto finish;
 490         }
 491
 492         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
 493         if (fd < 0) {
 494                 r = -errno;
 495                 goto finish;
 496         }
 497
 498         (void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
 499
 500         iovec.iov_len = strlen(state);
 501
 502         strncpy(sockaddr.un.sun_path, e, sizeof(sockaddr.un.sun_path));
 503         if (sockaddr.un.sun_path[0] == '@')
 504                 sockaddr.un.sun_path[0] = 0;
 505
 506         msghdr.msg_namelen = SOCKADDR_UN_LEN(sockaddr.un);
 507
 508         send_ucred =
 509                 (pid != 0 && pid != getpid_cached()) ||
 510                 getuid() != geteuid() ||
 511                 getgid() != getegid();
 512
 513         if (n_fds > 0 || send_ucred) {
 514                 /* CMSG_SPACE(0) may return value different than zero, which results in miscalculated controllen. */
 515                 msghdr.msg_controllen =
 516                         (n_fds > 0 ? CMSG_SPACE(sizeof(int) * n_fds) : 0) +
 517                         (send_ucred ? CMSG_SPACE(sizeof(struct ucred)) : 0);
 518
 519                 msghdr.msg_control = alloca0(msghdr.msg_controllen);
 520
 521                 cmsg = CMSG_FIRSTHDR(&msghdr);
 522                 if (n_fds > 0) {
 523                         cmsg->cmsg_level = SOL_SOCKET;
 524                         cmsg->cmsg_type = SCM_RIGHTS;
 525                         cmsg->cmsg_len = CMSG_LEN(sizeof(int) * n_fds);
 526
 527                         memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * n_fds);
 528
 529                         if (send_ucred)
 530                                 assert_se(cmsg = CMSG_NXTHDR(&msghdr, cmsg));
 531                 }
 532
 533                 if (send_ucred) {
 534                         struct ucred *ucred;
 535
 536                         cmsg->cmsg_level = SOL_SOCKET;
 537                         cmsg->cmsg_type = SCM_CREDENTIALS;
 538                         cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
 539
 540                         ucred = (struct ucred*) CMSG_DATA(cmsg);
 541                         ucred->pid = pid != 0 ? pid : getpid_cached();
 542                         ucred->uid = getuid();
 543                         ucred->gid = getgid();
 544                 }
 545         }
 546
 547         /* First try with fake ucred data, as requested */
 548         if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 549                 r = 1;
 550                 goto finish;
 551         }
 552
 553         /* If that failed, try with our own ucred instead */
 554         if (send_ucred) {
 555                 msghdr.msg_controllen -= CMSG_SPACE(sizeof(struct ucred));
 556                 if (msghdr.msg_controllen == 0)
 557                         msghdr.msg_control = NULL;
 558
 559                 if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 560                         r = 1;
 561                         goto finish;
 562                 }
 563         }
 564
 565         r = -errno;
 566
 567 finish:
 568         if (unset_environment)
 569                 unsetenv("NOTIFY_SOCKET");
 570
 571         return r;
 572 }
 573
 574 _public_ int sd_pid_notify(pid_t pid, int unset_environment, const char *state) {
 575         return sd_pid_notify_with_fds(pid, unset_environment, state, NULL, 0);
 576 }
 577
 578 _public_ int sd_notify(int unset_environment, const char *state) {
 579         return sd_pid_notify_with_fds(0, unset_environment, state, NULL, 0);
 580 }
 581
 582 _public_ int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) {
 583         _cleanup_free_ char *p = NULL;
 584         int r;
 585
 586         if (format) {
 587                 va_list ap;
 588
 589                 va_start(ap, format);
 590                 r = vasprintf(&p, format, ap);
 591                 va_end(ap);
 592
 593                 if (r < 0 || !p)
 594                         return -ENOMEM;
 595         }
 596
 597         return sd_pid_notify(pid, unset_environment, p);
 598 }
 599
 600 _public_ int sd_notifyf(int unset_environment, const char *format, ...) {
 601         _cleanup_free_ char *p = NULL;
 602         int r;
 603
 604         if (format) {
 605                 va_list ap;
 606
 607                 va_start(ap, format);
 608                 r = vasprintf(&p, format, ap);
 609                 va_end(ap);
 610
 611                 if (r < 0 || !p)
 612                         return -ENOMEM;
 613         }
 614
 615         return sd_pid_notify(0, unset_environment, p);
 616 }
 617
 618 _public_ int sd_booted(void) {
 619         /* We test whether the runtime unit file directory has been
 620          * created. This takes place in mount-setup.c, so is
 621          * guaranteed to happen very early during boot. */
 622
 623         return laccess("/run/systemd/system/", F_OK) >= 0;
 624 }
 625
 626 _public_ int sd_watchdog_enabled(int unset_environment, uint64_t *usec) {
 627         const char *s, *p = ""; /* p is set to dummy value to do unsetting */
 628         uint64_t u;
 629         int r = 0;
 630
 631         s = getenv("WATCHDOG_USEC");
 632         if (!s)
 633                 goto finish;
 634
 635         r = safe_atou64(s, &u);
 636         if (r < 0)
 637                 goto finish;
 638         if (u <= 0 || u >= USEC_INFINITY) {
 639                 r = -EINVAL;
 640                 goto finish;
 641         }
 642
 643         p = getenv("WATCHDOG_PID");
 644         if (p) {
 645                 pid_t pid;
 646
 647                 r = parse_pid(p, &pid);
 648                 if (r < 0)
 649                         goto finish;
 650
 651                 /* Is this for us? */
 652                 if (getpid_cached() != pid) {
 653                         r = 0;
 654                         goto finish;
 655                 }
 656         }
 657
 658         if (usec)
 659                 *usec = u;
 660
 661         r = 1;
 662
 663 finish:
 664         if (unset_environment && s)
 665                 unsetenv("WATCHDOG_USEC");
 666         if (unset_environment && p)
 667                 unsetenv("WATCHDOG_PID");
 668
 669         return r;
 670 }