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

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