src/libsystemd-daemon/sd-daemon.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   Copyright 2010 Lennart Poettering
   5
   6   Permission is hereby granted, free of charge, to any person
   7   obtaining a copy of this software and associated documentation files
   8   (the "Software"), to deal in the Software without restriction,
   9   including without limitation the rights to use, copy, modify, merge,
  10   publish, distribute, sublicense, and/or sell copies of the Software,
  11   and to permit persons to whom the Software is furnished to do so,
  12   subject to the following conditions:
  13
  14   The above copyright notice and this permission notice shall be
  15   included in all copies or substantial portions of the Software.
  16
  17   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  21   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  22   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  23   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24   SOFTWARE.
  25 ***/
  26
  27 #ifndef _GNU_SOURCE
  28 #  define _GNU_SOURCE
  29 #endif
  30
  31 #include <sys/types.h>
  32 #include <sys/stat.h>
  33 #include <sys/socket.h>
  34 #include <sys/un.h>
  35 #ifdef __BIONIC__
  36 #  include <linux/fcntl.h>
  37 #else
  38 #  include <sys/fcntl.h>
  39 #endif
  40 #include <netinet/in.h>
  41 #include <stdlib.h>
  42 #include <errno.h>
  43 #include <unistd.h>
  44 #include <string.h>
  45 #include <stdarg.h>
  46 #include <stdio.h>
  47 #include <stddef.h>
  48 #include <limits.h>
  49
  50 #if defined(__linux__)
  51 #  include <mqueue.h>
  52 #endif
  53
  54 #include "sd-daemon.h"
  55
  56 #if (__GNUC__ >= 4)
  57 #  ifdef SD_EXPORT_SYMBOLS
  58 /* Export symbols */
  59 #    define _sd_export_ __attribute__ ((visibility("default")))
  60 #  else
  61 /* Don't export the symbols */
  62 #    define _sd_export_ __attribute__ ((visibility("hidden")))
  63 #  endif
  64 #else
  65 #  define _sd_export_
  66 #endif
  67
  68 _sd_export_ int sd_listen_fds(int unset_environment) {
  69
  70 #if defined(DISABLE_SYSTEMD) || !defined(__linux__)
  71         return 0;
  72 #else
  73         int r, fd;
  74         const char *e;
  75         char *p = NULL;
  76         unsigned long l;
  77
  78         e = getenv("LISTEN_PID");
  79         if (!e) {
  80                 r = 0;
  81                 goto finish;
  82         }
  83
  84         errno = 0;
  85         l = strtoul(e, &p, 10);
  86
  87         if (errno > 0) {
  88                 r = -errno;
  89                 goto finish;
  90         }
  91
  92         if (!p || p == e || *p || l <= 0) {
  93                 r = -EINVAL;
  94                 goto finish;
  95         }
  96
  97         /* Is this for us? */
  98         if (getpid() != (pid_t) l) {
  99                 r = 0;
 100                 goto finish;
 101         }
 102
 103         e = getenv("LISTEN_FDS");
 104         if (!e) {
 105                 r = 0;
 106                 goto finish;
 107         }
 108
 109         errno = 0;
 110         l = strtoul(e, &p, 10);
 111
 112         if (errno > 0) {
 113                 r = -errno;
 114                 goto finish;
 115         }
 116
 117         if (!p || p == e || *p) {
 118                 r = -EINVAL;
 119                 goto finish;
 120         }
 121
 122         for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + (int) l; fd ++) {
 123                 int flags;
 124
 125                 flags = fcntl(fd, F_GETFD);
 126                 if (flags < 0) {
 127                         r = -errno;
 128                         goto finish;
 129                 }
 130
 131                 if (flags & FD_CLOEXEC)
 132                         continue;
 133
 134                 if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
 135                         r = -errno;
 136                         goto finish;
 137                 }
 138         }
 139
 140         r = (int) l;
 141
 142 finish:
 143         if (unset_environment) {
 144                 unsetenv("LISTEN_PID");
 145                 unsetenv("LISTEN_FDS");
 146         }
 147
 148         return r;
 149 #endif
 150 }
 151
 152 _sd_export_ int sd_is_fifo(int fd, const char *path) {
 153         struct stat st_fd;
 154
 155         if (fd < 0)
 156                 return -EINVAL;
 157
 158         if (fstat(fd, &st_fd) < 0)
 159                 return -errno;
 160
 161         if (!S_ISFIFO(st_fd.st_mode))
 162                 return 0;
 163
 164         if (path) {
 165                 struct stat st_path;
 166
 167                 if (stat(path, &st_path) < 0) {
 168
 169                         if (errno == ENOENT || errno == ENOTDIR)
 170                                 return 0;
 171
 172                         return -errno;
 173                 }
 174
 175                 return
 176                         st_path.st_dev == st_fd.st_dev &&
 177                         st_path.st_ino == st_fd.st_ino;
 178         }
 179
 180         return 1;
 181 }
 182
 183 _sd_export_ int sd_is_special(int fd, const char *path) {
 184         struct stat st_fd;
 185
 186         if (fd < 0)
 187                 return -EINVAL;
 188
 189         if (fstat(fd, &st_fd) < 0)
 190                 return -errno;
 191
 192         if (!S_ISREG(st_fd.st_mode) && !S_ISCHR(st_fd.st_mode))
 193                 return 0;
 194
 195         if (path) {
 196                 struct stat st_path;
 197
 198                 if (stat(path, &st_path) < 0) {
 199
 200                         if (errno == ENOENT || errno == ENOTDIR)
 201                                 return 0;
 202
 203                         return -errno;
 204                 }
 205
 206                 if (S_ISREG(st_fd.st_mode) && S_ISREG(st_path.st_mode))
 207                         return
 208                                 st_path.st_dev == st_fd.st_dev &&
 209                                 st_path.st_ino == st_fd.st_ino;
 210                 else if (S_ISCHR(st_fd.st_mode) && S_ISCHR(st_path.st_mode))
 211                         return st_path.st_rdev == st_fd.st_rdev;
 212                 else
 213                         return 0;
 214         }
 215
 216         return 1;
 217 }
 218
 219 static int sd_is_socket_internal(int fd, int type, int listening) {
 220         struct stat st_fd;
 221
 222         if (fd < 0 || type < 0)
 223                 return -EINVAL;
 224
 225         if (fstat(fd, &st_fd) < 0)
 226                 return -errno;
 227
 228         if (!S_ISSOCK(st_fd.st_mode))
 229                 return 0;
 230
 231         if (type != 0) {
 232                 int other_type = 0;
 233                 socklen_t l = sizeof(other_type);
 234
 235                 if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
 236                         return -errno;
 237
 238                 if (l != sizeof(other_type))
 239                         return -EINVAL;
 240
 241                 if (other_type != type)
 242                         return 0;
 243         }
 244
 245         if (listening >= 0) {
 246                 int accepting = 0;
 247                 socklen_t l = sizeof(accepting);
 248
 249                 if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
 250                         return -errno;
 251
 252                 if (l != sizeof(accepting))
 253                         return -EINVAL;
 254
 255                 if (!accepting != !listening)
 256                         return 0;
 257         }
 258
 259         return 1;
 260 }
 261
 262 union sockaddr_union {
 263         struct sockaddr sa;
 264         struct sockaddr_in in4;
 265         struct sockaddr_in6 in6;
 266         struct sockaddr_un un;
 267         struct sockaddr_storage storage;
 268 };
 269
 270 _sd_export_ int sd_is_socket(int fd, int family, int type, int listening) {
 271         int r;
 272
 273         if (family < 0)
 274                 return -EINVAL;
 275
 276         r = sd_is_socket_internal(fd, type, listening);
 277         if (r <= 0)
 278                 return r;
 279
 280         if (family > 0) {
 281                 union sockaddr_union sockaddr;
 282                 socklen_t l;
 283
 284                 memset(&sockaddr, 0, sizeof(sockaddr));
 285                 l = sizeof(sockaddr);
 286
 287                 if (getsockname(fd, &sockaddr.sa, &l) < 0)
 288                         return -errno;
 289
 290                 if (l < sizeof(sa_family_t))
 291                         return -EINVAL;
 292
 293                 return sockaddr.sa.sa_family == family;
 294         }
 295
 296         return 1;
 297 }
 298
 299 _sd_export_ int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
 300         union sockaddr_union sockaddr;
 301         socklen_t l;
 302         int r;
 303
 304         if (family != 0 && family != AF_INET && family != AF_INET6)
 305                 return -EINVAL;
 306
 307         r = sd_is_socket_internal(fd, type, listening);
 308         if (r <= 0)
 309                 return r;
 310
 311         memset(&sockaddr, 0, sizeof(sockaddr));
 312         l = sizeof(sockaddr);
 313
 314         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 315                 return -errno;
 316
 317         if (l < sizeof(sa_family_t))
 318                 return -EINVAL;
 319
 320         if (sockaddr.sa.sa_family != AF_INET &&
 321             sockaddr.sa.sa_family != AF_INET6)
 322                 return 0;
 323
 324         if (family > 0)
 325                 if (sockaddr.sa.sa_family != family)
 326                         return 0;
 327
 328         if (port > 0) {
 329                 if (sockaddr.sa.sa_family == AF_INET) {
 330                         if (l < sizeof(struct sockaddr_in))
 331                                 return -EINVAL;
 332
 333                         return htons(port) == sockaddr.in4.sin_port;
 334                 } else {
 335                         if (l < sizeof(struct sockaddr_in6))
 336                                 return -EINVAL;
 337
 338                         return htons(port) == sockaddr.in6.sin6_port;
 339                 }
 340         }
 341
 342         return 1;
 343 }
 344
 345 _sd_export_ int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
 346         union sockaddr_union sockaddr;
 347         socklen_t l;
 348         int r;
 349
 350         r = sd_is_socket_internal(fd, type, listening);
 351         if (r <= 0)
 352                 return r;
 353
 354         memset(&sockaddr, 0, sizeof(sockaddr));
 355         l = sizeof(sockaddr);
 356
 357         if (getsockname(fd, &sockaddr.sa, &l) < 0)
 358                 return -errno;
 359
 360         if (l < sizeof(sa_family_t))
 361                 return -EINVAL;
 362
 363         if (sockaddr.sa.sa_family != AF_UNIX)
 364                 return 0;
 365
 366         if (path) {
 367                 if (length == 0)
 368                         length = strlen(path);
 369
 370                 if (length == 0)
 371                         /* Unnamed socket */
 372                         return l == offsetof(struct sockaddr_un, sun_path);
 373
 374                 if (path[0])
 375                         /* Normal path socket */
 376                         return
 377                                 (l >= offsetof(struct sockaddr_un, sun_path) + length + 1) &&
 378                                 memcmp(path, sockaddr.un.sun_path, length+1) == 0;
 379                 else
 380                         /* Abstract namespace socket */
 381                         return
 382                                 (l == offsetof(struct sockaddr_un, sun_path) + length) &&
 383                                 memcmp(path, sockaddr.un.sun_path, length) == 0;
 384         }
 385
 386         return 1;
 387 }
 388
 389 _sd_export_ int sd_is_mq(int fd, const char *path) {
 390 #if !defined(__linux__)
 391         return 0;
 392 #else
 393         struct mq_attr attr;
 394
 395         if (fd < 0)
 396                 return -EINVAL;
 397
 398         if (mq_getattr(fd, &attr) < 0)
 399                 return -errno;
 400
 401         if (path) {
 402                 char fpath[PATH_MAX];
 403                 struct stat a, b;
 404
 405                 if (path[0] != '/')
 406                         return -EINVAL;
 407
 408                 if (fstat(fd, &a) < 0)
 409                         return -errno;
 410
 411                 strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
 412                 fpath[sizeof(fpath)-1] = 0;
 413
 414                 if (stat(fpath, &b) < 0)
 415                         return -errno;
 416
 417                 if (a.st_dev != b.st_dev ||
 418                     a.st_ino != b.st_ino)
 419                         return 0;
 420         }
 421
 422         return 1;
 423 #endif
 424 }
 425
 426 _sd_export_ int sd_notify(int unset_environment, const char *state) {
 427 #if defined(DISABLE_SYSTEMD) || !defined(__linux__) || !defined(SOCK_CLOEXEC)
 428         return 0;
 429 #else
 430         int fd = -1, r;
 431         struct msghdr msghdr;
 432         struct iovec iovec;
 433         union sockaddr_union sockaddr;
 434         const char *e;
 435
 436         if (!state) {
 437                 r = -EINVAL;
 438                 goto finish;
 439         }
 440
 441         e = getenv("NOTIFY_SOCKET");
 442         if (!e)
 443                 return 0;
 444
 445         /* Must be an abstract socket, or an absolute path */
 446         if ((e[0] != '@' && e[0] != '/') || e[1] == 0) {
 447                 r = -EINVAL;
 448                 goto finish;
 449         }
 450
 451         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
 452         if (fd < 0) {
 453                 r = -errno;
 454                 goto finish;
 455         }
 456
 457         memset(&sockaddr, 0, sizeof(sockaddr));
 458         sockaddr.sa.sa_family = AF_UNIX;
 459         strncpy(sockaddr.un.sun_path, e, sizeof(sockaddr.un.sun_path));
 460
 461         if (sockaddr.un.sun_path[0] == '@')
 462                 sockaddr.un.sun_path[0] = 0;
 463
 464         memset(&iovec, 0, sizeof(iovec));
 465         iovec.iov_base = (char*) state;
 466         iovec.iov_len = strlen(state);
 467
 468         memset(&msghdr, 0, sizeof(msghdr));
 469         msghdr.msg_name = &sockaddr;
 470         msghdr.msg_namelen = offsetof(struct sockaddr_un, sun_path) + strlen(e);
 471
 472         if (msghdr.msg_namelen > sizeof(struct sockaddr_un))
 473                 msghdr.msg_namelen = sizeof(struct sockaddr_un);
 474
 475         msghdr.msg_iov = &iovec;
 476         msghdr.msg_iovlen = 1;
 477
 478         if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) < 0) {
 479                 r = -errno;
 480                 goto finish;
 481         }
 482
 483         r = 1;
 484
 485 finish:
 486         if (unset_environment)
 487                 unsetenv("NOTIFY_SOCKET");
 488
 489         if (fd >= 0)
 490                 close(fd);
 491
 492         return r;
 493 #endif
 494 }
 495
 496 _sd_export_ int sd_notifyf(int unset_environment, const char *format, ...) {
 497 #if defined(DISABLE_SYSTEMD) || !defined(__linux__)
 498         return 0;
 499 #else
 500         va_list ap;
 501         char *p = NULL;
 502         int r;
 503
 504         va_start(ap, format);
 505         r = vasprintf(&p, format, ap);
 506         va_end(ap);
 507
 508         if (r < 0 || !p)
 509                 return -ENOMEM;
 510
 511         r = sd_notify(unset_environment, p);
 512         free(p);
 513
 514         return r;
 515 #endif
 516 }
 517
 518 _sd_export_ int sd_booted(void) {
 519 #if defined(DISABLE_SYSTEMD) || !defined(__linux__)
 520         return 0;
 521 #else
 522         struct stat st;
 523
 524         /* We test whether the runtime unit file directory has been
 525          * created. This takes place in mount-setup.c, so is
 526          * guaranteed to happen very early during boot. */
 527
 528         if (lstat("/run/systemd/system/", &st) < 0)
 529                 return 0;
 530
 531         return !!S_ISDIR(st.st_mode);
 532 #endif
 533 }