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         assert_return(fd >= 0, -EBADF);
 314
 315         if (mq_getattr(fd, &attr) < 0)
 316                 return -errno;
 317
 318         if (path) {
 319                 char fpath[PATH_MAX];
 320                 struct stat a, b;
 321
 322                 assert_return(path_is_absolute(path), -EINVAL);
 323
 324                 if (fstat(fd, &a) < 0)
 325                         return -errno;
 326
 327                 strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
 328                 fpath[sizeof(fpath)-1] = 0;
 329
 330                 if (stat(fpath, &b) < 0)
 331                         return -errno;
 332
 333                 if (a.st_dev != b.st_dev ||
 334                     a.st_ino != b.st_ino)
 335                         return 0;
 336         }
 337
 338         return 1;
 339 }
 340
 341 _public_ int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char *state, const int *fds, unsigned n_fds) {
 342         union sockaddr_union sockaddr = {
 343                 .sa.sa_family = AF_UNIX,
 344         };
 345         struct iovec iovec = {
 346                 .iov_base = (char*) state,
 347         };
 348         struct msghdr msghdr = {
 349                 .msg_iov = &iovec,
 350                 .msg_iovlen = 1,
 351                 .msg_name = &sockaddr,
 352         };
 353         _cleanup_close_ int fd = -1;
 354         struct cmsghdr *cmsg = NULL;
 355         const char *e;
 356         bool have_pid;
 357         int r;
 358
 359         if (!state) {
 360                 r = -EINVAL;
 361                 goto finish;
 362         }
 363
 364         if (n_fds > 0 && !fds) {
 365                 r = -EINVAL;
 366                 goto finish;
 367         }
 368
 369         e = getenv("NOTIFY_SOCKET");
 370         if (!e)
 371                 return 0;
 372
 373         /* Must be an abstract socket, or an absolute path */
 374         if ((e[0] != '@' && e[0] != '/') || e[1] == 0) {
 375                 r = -EINVAL;
 376                 goto finish;
 377         }
 378
 379         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
 380         if (fd < 0) {
 381                 r = -errno;
 382                 goto finish;
 383         }
 384
 385         iovec.iov_len = strlen(state);
 386
 387         strncpy(sockaddr.un.sun_path, e, sizeof(sockaddr.un.sun_path));
 388         if (sockaddr.un.sun_path[0] == '@')
 389                 sockaddr.un.sun_path[0] = 0;
 390
 391         msghdr.msg_namelen = offsetof(struct sockaddr_un, sun_path) + strlen(e);
 392         if (msghdr.msg_namelen > sizeof(struct sockaddr_un))
 393                 msghdr.msg_namelen = sizeof(struct sockaddr_un);
 394
 395         have_pid = pid != 0 && pid != getpid();
 396
 397         if (n_fds > 0 || have_pid) {
 398                 /* CMSG_SPACE(0) may return value different then zero, which results in miscalculated controllen. */
 399                 msghdr.msg_controllen = (n_fds ? CMSG_SPACE(sizeof(int) * n_fds) : 0) +
 400                                         CMSG_SPACE(sizeof(struct ucred)) * have_pid;
 401                 msghdr.msg_control = alloca(msghdr.msg_controllen);
 402
 403                 cmsg = CMSG_FIRSTHDR(&msghdr);
 404                 if (n_fds > 0) {
 405                         cmsg->cmsg_level = SOL_SOCKET;
 406                         cmsg->cmsg_type = SCM_RIGHTS;
 407                         cmsg->cmsg_len = CMSG_LEN(sizeof(int) * n_fds);
 408
 409                         memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * n_fds);
 410
 411                         if (have_pid)
 412                                 assert_se(cmsg = CMSG_NXTHDR(&msghdr, cmsg));
 413                 }
 414
 415                 if (have_pid) {
 416                         struct ucred *ucred;
 417
 418                         cmsg->cmsg_level = SOL_SOCKET;
 419                         cmsg->cmsg_type = SCM_CREDENTIALS;
 420                         cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
 421
 422                         ucred = (struct ucred*) CMSG_DATA(cmsg);
 423                         ucred->pid = pid;
 424                         ucred->uid = getuid();
 425                         ucred->gid = getgid();
 426                 }
 427         }
 428
 429         /* First try with fake ucred data, as requested */
 430         if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 431                 r = 1;
 432                 goto finish;
 433         }
 434
 435         /* If that failed, try with our own ucred instead */
 436         if (have_pid) {
 437                 msghdr.msg_controllen -= CMSG_SPACE(sizeof(struct ucred));
 438                 if (msghdr.msg_controllen == 0)
 439                         msghdr.msg_control = NULL;
 440
 441                 if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
 442                         r = 1;
 443                         goto finish;
 444                 }
 445         }
 446
 447         r = -errno;
 448
 449 finish:
 450         if (unset_environment)
 451                 unsetenv("NOTIFY_SOCKET");
 452
 453         return r;
 454 }
 455
 456 _public_ int sd_pid_notify(pid_t pid, int unset_environment, const char *state) {
 457         return sd_pid_notify_with_fds(pid, unset_environment, state, NULL, 0);
 458 }
 459
 460 _public_ int sd_notify(int unset_environment, const char *state) {
 461         return sd_pid_notify_with_fds(0, unset_environment, state, NULL, 0);
 462 }
 463
 464 _public_ int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) {
 465         _cleanup_free_ char *p = NULL;
 466         int r;
 467
 468         if (format) {
 469                 va_list ap;
 470
 471                 va_start(ap, format);
 472                 r = vasprintf(&p, format, ap);
 473                 va_end(ap);
 474
 475                 if (r < 0 || !p)
 476                         return -ENOMEM;
 477         }
 478
 479         return sd_pid_notify(pid, unset_environment, p);
 480 }
 481
 482 _public_ int sd_notifyf(int unset_environment, const char *format, ...) {
 483         _cleanup_free_ char *p = NULL;
 484         int r;
 485
 486         if (format) {
 487                 va_list ap;
 488
 489                 va_start(ap, format);
 490                 r = vasprintf(&p, format, ap);
 491                 va_end(ap);
 492
 493                 if (r < 0 || !p)
 494                         return -ENOMEM;
 495         }
 496
 497         return sd_pid_notify(0, unset_environment, p);
 498 }
 499
 500 _public_ int sd_booted(void) {
 501         struct stat st;
 502
 503         /* We test whether the runtime unit file directory has been
 504          * created. This takes place in mount-setup.c, so is
 505          * guaranteed to happen very early during boot. */
 506
 507         if (lstat("/run/systemd/system/", &st) < 0)
 508                 return 0;
 509
 510         return !!S_ISDIR(st.st_mode);
 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 }