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

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