src/notify/notify.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4 #include <getopt.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8
   9 #include "sd-daemon.h"
  10
  11 #include "alloc-util.h"
  12 #include "build.h"
  13 #include "env-util.h"
  14 #include "fd-util.h"
  15 #include "fdset.h"
  16 #include "format-util.h"
  17 #include "log.h"
  18 #include "main-func.h"
  19 #include "parse-util.h"
  20 #include "pretty-print.h"
  21 #include "process-util.h"
  22 #include "string-util.h"
  23 #include "strv.h"
  24 #include "terminal-util.h"
  25 #include "time-util.h"
  26 #include "user-util.h"
  27
  28 static bool arg_ready = false;
  29 static bool arg_reloading = false;
  30 static bool arg_stopping = false;
  31 static pid_t arg_pid = 0;
  32 static const char *arg_status = NULL;
  33 static bool arg_booted = false;
  34 static uid_t arg_uid = UID_INVALID;
  35 static gid_t arg_gid = GID_INVALID;
  36 static bool arg_no_block = false;
  37 static char **arg_env = NULL;
  38 static char **arg_exec = NULL;
  39 static FDSet *arg_fds = NULL;
  40 static char *arg_fdname = NULL;
  41
  42 STATIC_DESTRUCTOR_REGISTER(arg_env, strv_freep);
  43 STATIC_DESTRUCTOR_REGISTER(arg_exec, strv_freep);
  44 STATIC_DESTRUCTOR_REGISTER(arg_fds, fdset_freep);
  45 STATIC_DESTRUCTOR_REGISTER(arg_fdname, freep);
  46
  47 static int help(void) {
  48         _cleanup_free_ char *link = NULL;
  49         int r;
  50
  51         r = terminal_urlify_man("systemd-notify", "1", &link);
  52         if (r < 0)
  53                 return log_oom();
  54
  55         printf("%s [OPTIONS...] [VARIABLE=VALUE...]\n"
  56                "%s [OPTIONS...] --exec [VARIABLE=VALUE...] ; CMDLINE...\n"
  57                "\n%sNotify the init system about service status updates.%s\n\n"
  58                "  -h --help            Show this help\n"
  59                "     --version         Show package version\n"
  60                "     --ready           Inform the service manager about service start-up/reload\n"
  61                "                       completion\n"
  62                "     --reloading       Inform the service manager about configuration reloading\n"
  63                "     --stopping        Inform the service manager about service shutdown\n"
  64                "     --pid[=PID]       Set main PID of daemon\n"
  65                "     --uid=USER        Set user to send from\n"
  66                "     --status=TEXT     Set status text\n"
  67                "     --booted          Check if the system was booted up with systemd\n"
  68                "     --no-block        Do not wait until operation finished\n"
  69                "     --exec            Execute command line separated by ';' once done\n"
  70                "     --fd=FD           Pass specified file descriptor with along with message\n"
  71                "     --fdname=NAME     Name to assign to passed file descriptor(s)\n"
  72                "\nSee the %s for details.\n",
  73                program_invocation_short_name,
  74                program_invocation_short_name,
  75                ansi_highlight(),
  76                ansi_normal(),
  77                link);
  78
  79         return 0;
  80 }
  81
  82 static pid_t manager_pid(void) {
  83         const char *e;
  84         pid_t pid;
  85         int r;
  86
  87         /* If we run as a service managed by systemd --user the $MANAGERPID environment variable points to
  88          * the service manager's PID. */
  89         e = getenv("MANAGERPID");
  90         if (!e)
  91                 return 0;
  92
  93         r = parse_pid(e, &pid);
  94         if (r < 0) {
  95                 log_warning_errno(r, "$MANAGERPID is set to an invalid PID, ignoring: %s", e);
  96                 return 0;
  97         }
  98
  99         return pid;
 100 }
 101
 102 static int parse_argv(int argc, char *argv[]) {
 103
 104         enum {
 105                 ARG_READY = 0x100,
 106                 ARG_RELOADING,
 107                 ARG_STOPPING,
 108                 ARG_VERSION,
 109                 ARG_PID,
 110                 ARG_STATUS,
 111                 ARG_BOOTED,
 112                 ARG_UID,
 113                 ARG_NO_BLOCK,
 114                 ARG_EXEC,
 115                 ARG_FD,
 116                 ARG_FDNAME,
 117         };
 118
 119         static const struct option options[] = {
 120                 { "help",      no_argument,       NULL, 'h'           },
 121                 { "version",   no_argument,       NULL, ARG_VERSION   },
 122                 { "ready",     no_argument,       NULL, ARG_READY     },
 123                 { "reloading", no_argument,       NULL, ARG_RELOADING },
 124                 { "stopping",  no_argument,       NULL, ARG_STOPPING  },
 125                 { "pid",       optional_argument, NULL, ARG_PID       },
 126                 { "status",    required_argument, NULL, ARG_STATUS    },
 127                 { "booted",    no_argument,       NULL, ARG_BOOTED    },
 128                 { "uid",       required_argument, NULL, ARG_UID       },
 129                 { "no-block",  no_argument,       NULL, ARG_NO_BLOCK  },
 130                 { "exec",      no_argument,       NULL, ARG_EXEC      },
 131                 { "fd",        required_argument, NULL, ARG_FD        },
 132                 { "fdname",    required_argument, NULL, ARG_FDNAME    },
 133                 {}
 134         };
 135
 136         _cleanup_fdset_free_ FDSet *passed = NULL;
 137         bool do_exec = false;
 138         int c, r, n_env;
 139
 140         assert(argc >= 0);
 141         assert(argv);
 142
 143         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
 144
 145                 switch (c) {
 146
 147                 case 'h':
 148                         return help();
 149
 150                 case ARG_VERSION:
 151                         return version();
 152
 153                 case ARG_READY:
 154                         arg_ready = true;
 155                         break;
 156
 157                 case ARG_RELOADING:
 158                         arg_reloading = true;
 159                         break;
 160
 161                 case ARG_STOPPING:
 162                         arg_stopping = true;
 163                         break;
 164
 165                 case ARG_PID:
 166                         if (isempty(optarg) || streq(optarg, "auto")) {
 167                                 arg_pid = getppid();
 168
 169                                 if (arg_pid <= 1 ||
 170                                     arg_pid == manager_pid()) /* Don't send from PID 1 or the service
 171                                                                * manager's PID (which might be distinct from
 172                                                                * 1, if we are a --user instance), that'd just
 173                                                                * be confusing for the service manager */
 174                                         arg_pid = getpid_cached();
 175                         } else if (streq(optarg, "parent"))
 176                                 arg_pid = getppid();
 177                         else if (streq(optarg, "self"))
 178                                 arg_pid = getpid_cached();
 179                         else {
 180                                 r = parse_pid(optarg, &arg_pid);
 181                                 if (r < 0)
 182                                         return log_error_errno(r, "Failed to parse PID %s.", optarg);
 183                         }
 184
 185                         break;
 186
 187                 case ARG_STATUS:
 188                         arg_status = optarg;
 189                         break;
 190
 191                 case ARG_BOOTED:
 192                         arg_booted = true;
 193                         break;
 194
 195                 case ARG_UID: {
 196                         const char *u = optarg;
 197
 198                         r = get_user_creds(&u, &arg_uid, &arg_gid, NULL, NULL, 0);
 199                         if (r == -ESRCH) /* If the user doesn't exist, then accept it anyway as numeric */
 200                                 r = parse_uid(u, &arg_uid);
 201                         if (r < 0)
 202                                 return log_error_errno(r, "Can't resolve user %s: %m", optarg);
 203
 204                         break;
 205                 }
 206
 207                 case ARG_NO_BLOCK:
 208                         arg_no_block = true;
 209                         break;
 210
 211                 case ARG_EXEC:
 212                         do_exec = true;
 213                         break;
 214
 215                 case ARG_FD: {
 216                         _cleanup_close_ int owned_fd = -EBADF;
 217                         int fdnr;
 218
 219                         fdnr = parse_fd(optarg);
 220                         if (fdnr < 0)
 221                                 return log_error_errno(fdnr, "Failed to parse file descriptor: %s", optarg);
 222
 223                         if (!passed) {
 224                                 /* Take possession of all passed fds */
 225                                 r = fdset_new_fill(/* filter_cloexec= */ 0, &passed);
 226                                 if (r < 0)
 227                                         return log_error_errno(r, "Failed to take possession of passed file descriptors: %m");
 228                         }
 229
 230                         if (fdnr < 3) {
 231                                 /* For stdin/stdout/stderr we want to keep the fd, too, hence make a copy */
 232                                 owned_fd = fcntl(fdnr, F_DUPFD_CLOEXEC, 3);
 233                                 if (owned_fd < 0)
 234                                         return log_error_errno(errno, "Failed to duplicate file descriptor: %m");
 235                         } else {
 236                                 /* Otherwise, move the fd over */
 237                                 owned_fd = fdset_remove(passed, fdnr);
 238                                 if (owned_fd < 0)
 239                                         return log_error_errno(owned_fd, "Specified file descriptor '%i' not passed or specified more than once: %m", fdnr);
 240                         }
 241
 242                         if (!arg_fds) {
 243                                 arg_fds = fdset_new();
 244                                 if (!arg_fds)
 245                                         return log_oom();
 246                         }
 247
 248                         r = fdset_consume(arg_fds, TAKE_FD(owned_fd));
 249                         if (r < 0)
 250                                 return log_error_errno(r, "Failed to add file descriptor to set: %m");
 251                         break;
 252                 }
 253
 254                 case ARG_FDNAME:
 255                         if (!fdname_is_valid(optarg))
 256                                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "File descriptor name invalid: %s", optarg);
 257
 258                         if (free_and_strdup(&arg_fdname, optarg) < 0)
 259                                 return log_oom();
 260
 261                         break;
 262
 263                 case '?':
 264                         return -EINVAL;
 265
 266                 default:
 267                         assert_not_reached();
 268                 }
 269         }
 270
 271         if (optind >= argc &&
 272             !arg_ready &&
 273             !arg_stopping &&
 274             !arg_reloading &&
 275             !arg_status &&
 276             !arg_pid &&
 277             !arg_booted &&
 278             fdset_isempty(arg_fds)) {
 279                 help();
 280                 return -EINVAL;
 281         }
 282
 283         if (arg_fdname && fdset_isempty(arg_fds))
 284                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "No file descriptors passed, but --fdname= set, refusing.");
 285
 286         if (do_exec) {
 287                 int i;
 288
 289                 for (i = optind; i < argc; i++)
 290                         if (streq(argv[i], ";"))
 291                                 break;
 292
 293                 if (i >= argc)
 294                         return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "If --exec is used argument list must contain ';' separator, refusing.");
 295                 if (i+1 == argc)
 296                         return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Empty command line specified after ';' separator, refusing");
 297
 298                 arg_exec = strv_copy_n(argv + i + 1, argc - i - 1);
 299                 if (!arg_exec)
 300                         return log_oom();
 301
 302                 n_env = i - optind;
 303         } else
 304                 n_env = argc - optind;
 305
 306         if (n_env > 0) {
 307                 arg_env = strv_copy_n(argv + optind, n_env);
 308                 if (!arg_env)
 309                         return log_oom();
 310         }
 311
 312         if (!fdset_isempty(passed))
 313                 log_warning("Warning: %u more file descriptors passed than referenced with --fd=.", fdset_size(passed));
 314
 315         return 1;
 316 }
 317
 318 static int run(int argc, char* argv[]) {
 319         _cleanup_free_ char *status = NULL, *cpid = NULL, *n = NULL, *monotonic_usec = NULL, *fdn = NULL;
 320         _cleanup_strv_free_ char **final_env = NULL;
 321         char* our_env[9];
 322         size_t i = 0;
 323         pid_t source_pid;
 324         int r;
 325
 326         log_show_color(true);
 327         log_parse_environment();
 328         log_open();
 329
 330         r = parse_argv(argc, argv);
 331         if (r <= 0)
 332                 return r;
 333
 334         if (arg_booted) {
 335                 r = sd_booted();
 336                 if (r < 0)
 337                         log_debug_errno(r, "Failed to determine whether we are booted with systemd, assuming we aren't: %m");
 338                 else
 339                         log_debug("The system %s booted with systemd.", r ? "was" : "was not");
 340
 341                 return r <= 0;
 342         }
 343
 344         if (arg_reloading) {
 345                 our_env[i++] = (char*) "RELOADING=1";
 346
 347                 if (asprintf(&monotonic_usec, "MONOTONIC_USEC=" USEC_FMT, now(CLOCK_MONOTONIC)) < 0)
 348                         return log_oom();
 349
 350                 our_env[i++] = monotonic_usec;
 351         }
 352
 353         if (arg_ready)
 354                 our_env[i++] = (char*) "READY=1";
 355
 356         if (arg_stopping)
 357                 our_env[i++] = (char*) "STOPPING=1";
 358
 359         if (arg_status) {
 360                 status = strjoin("STATUS=", arg_status);
 361                 if (!status)
 362                         return log_oom();
 363
 364                 our_env[i++] = status;
 365         }
 366
 367         if (arg_pid > 0) {
 368                 if (asprintf(&cpid, "MAINPID="PID_FMT, arg_pid) < 0)
 369                         return log_oom();
 370
 371                 our_env[i++] = cpid;
 372         }
 373
 374         if (!fdset_isempty(arg_fds)) {
 375                 our_env[i++] = (char*) "FDSTORE=1";
 376
 377                 if (arg_fdname) {
 378                         fdn = strjoin("FDNAME=", arg_fdname);
 379                         if (!fdn)
 380                                 return log_oom();
 381
 382                         our_env[i++] = fdn;
 383                 }
 384         }
 385
 386         our_env[i++] = NULL;
 387
 388         final_env = strv_env_merge(our_env, arg_env);
 389         if (!final_env)
 390                 return log_oom();
 391
 392         if (strv_isempty(final_env))
 393                 return 0;
 394
 395         n = strv_join(final_env, "\n");
 396         if (!n)
 397                 return log_oom();
 398
 399         /* If this is requested change to the requested UID/GID. Note that we only change the real UID here, and leave
 400            the effective UID in effect (which is 0 for this to work). That's because we want the privileges to fake the
 401            ucred data, and sd_pid_notify() uses the real UID for filling in ucred. */
 402
 403         if (arg_gid != GID_INVALID &&
 404             setregid(arg_gid, GID_INVALID) < 0)
 405                 return log_error_errno(errno, "Failed to change GID: %m");
 406
 407         if (arg_uid != UID_INVALID &&
 408             setreuid(arg_uid, UID_INVALID) < 0)
 409                 return log_error_errno(errno, "Failed to change UID: %m");
 410
 411         if (arg_pid > 0)
 412                 source_pid = arg_pid;
 413         else {
 414                 /* Pretend the message originates from our parent, given that we are typically called from a
 415                  * shell script, i.e. we are not the main process of a service but only a child of it. */
 416                 source_pid = getppid();
 417                 if (source_pid <= 1 ||
 418                     source_pid == manager_pid()) /* safety check: don't claim we'd send anything from PID 1
 419                                                   * or the service manager itself */
 420                         source_pid = 0;
 421         }
 422
 423         if (fdset_isempty(arg_fds))
 424                 r = sd_pid_notify(source_pid, /* unset_environment= */ false, n);
 425         else {
 426                 _cleanup_free_ int *a = NULL;
 427                 int k;
 428
 429                 k = fdset_to_array(arg_fds, &a);
 430                 if (k < 0)
 431                         return log_error_errno(k, "Failed to convert file descriptor set to array: %m");
 432
 433                 r = sd_pid_notify_with_fds(source_pid, /* unset_environment= */ false, n, a, k);
 434
 435         }
 436         if (r < 0)
 437                 return log_error_errno(r, "Failed to notify init system: %m");
 438         if (r == 0)
 439                 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
 440                                        "No status data could be sent: $NOTIFY_SOCKET was not set");
 441
 442         arg_fds = fdset_free(arg_fds); /* Close before we execute anything */
 443
 444         if (!arg_no_block) {
 445                 r = sd_pid_notify_barrier(source_pid, /* unset_environment= */ false, 5 * USEC_PER_SEC);
 446                 if (r < 0)
 447                         return log_error_errno(r, "Failed to invoke barrier: %m");
 448                 if (r == 0)
 449                         return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
 450                                                "No status data could be sent: $NOTIFY_SOCKET was not set");
 451         }
 452
 453         if (arg_exec) {
 454                 _cleanup_free_ char *cmdline = NULL;
 455
 456                 execvp(arg_exec[0], arg_exec);
 457
 458                 cmdline = strv_join(arg_exec, " ");
 459                 if (!cmdline)
 460                         return log_oom();
 461
 462                 return log_error_errno(errno, "Failed to execute command line: %s", cmdline);
 463         }
 464
 465         /* The DEFINE_MAIN_FUNCTION_WITH_POSITIVE_FAILURE() boilerplate will send the exit status via
 466          * sd_notify(). Which is normally fine, but very confusing in systemd-notify, whose purpose is to
 467          * send user-controllable notification messages, and not implicit ones. Let's turn if off, by
 468          * unsetting the $NOTIFY_SOCKET environment variable. */
 469         (void) unsetenv("NOTIFY_SOCKET");
 470         return 0;
 471 }
 472
 473 DEFINE_MAIN_FUNCTION_WITH_POSITIVE_FAILURE(run);