src/initctl/initctl.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2010 Lennart Poettering
   4 ***/
   5
   6 #include <ctype.h>
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <sys/epoll.h>
  10 #include <unistd.h>
  11
  12 #include "sd-bus.h"
  13 #include "sd-daemon.h"
  14
  15 #include "alloc-util.h"
  16 #include "bus-error.h"
  17 #include "bus-util.h"
  18 #include "def.h"
  19 #include "fd-util.h"
  20 #include "format-util.h"
  21 #include "initreq.h"
  22 #include "list.h"
  23 #include "log.h"
  24 #include "special.h"
  25 #include "util.h"
  26 #include "process-util.h"
  27
  28 #define SERVER_FD_MAX 16
  29 #define TIMEOUT_MSEC ((int) (DEFAULT_EXIT_USEC/USEC_PER_MSEC))
  30
  31 typedef struct Fifo Fifo;
  32
  33 typedef struct Server {
  34         int epoll_fd;
  35
  36         LIST_HEAD(Fifo, fifos);
  37         unsigned n_fifos;
  38
  39         sd_bus *bus;
  40
  41         bool quit;
  42 } Server;
  43
  44 struct Fifo {
  45         Server *server;
  46
  47         int fd;
  48
  49         struct init_request buffer;
  50         size_t bytes_read;
  51
  52         LIST_FIELDS(Fifo, fifo);
  53 };
  54
  55 static const char *translate_runlevel(int runlevel, bool *isolate) {
  56         static const struct {
  57                 const int runlevel;
  58                 const char *special;
  59                 bool isolate;
  60         } table[] = {
  61                 { '0', SPECIAL_POWEROFF_TARGET,   false },
  62                 { '1', SPECIAL_RESCUE_TARGET,     true  },
  63                 { 's', SPECIAL_RESCUE_TARGET,     true  },
  64                 { 'S', SPECIAL_RESCUE_TARGET,     true  },
  65                 { '2', SPECIAL_MULTI_USER_TARGET, true  },
  66                 { '3', SPECIAL_MULTI_USER_TARGET, true  },
  67                 { '4', SPECIAL_MULTI_USER_TARGET, true  },
  68                 { '5', SPECIAL_GRAPHICAL_TARGET,  true  },
  69                 { '6', SPECIAL_REBOOT_TARGET,     false },
  70         };
  71
  72         unsigned i;
  73
  74         assert(isolate);
  75
  76         for (i = 0; i < ELEMENTSOF(table); i++)
  77                 if (table[i].runlevel == runlevel) {
  78                         *isolate = table[i].isolate;
  79                         if (runlevel == '6' && kexec_loaded())
  80                                 return SPECIAL_KEXEC_TARGET;
  81                         return table[i].special;
  82                 }
  83
  84         return NULL;
  85 }
  86
  87 static void change_runlevel(Server *s, int runlevel) {
  88         const char *target;
  89         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  90         const char *mode;
  91         bool isolate = false;
  92         int r;
  93
  94         assert(s);
  95
  96         target = translate_runlevel(runlevel, &isolate);
  97         if (!target) {
  98                 log_warning("Got request for unknown runlevel %c, ignoring.", runlevel);
  99                 return;
 100         }
 101
 102         if (isolate)
 103                 mode = "isolate";
 104         else
 105                 mode = "replace-irreversibly";
 106
 107         log_debug("Running request %s/start/%s", target, mode);
 108
 109         r = sd_bus_call_method(
 110                         s->bus,
 111                         "org.freedesktop.systemd1",
 112                         "/org/freedesktop/systemd1",
 113                         "org.freedesktop.systemd1.Manager",
 114                         "StartUnit",
 115                         &error,
 116                         NULL,
 117                         "ss", target, mode);
 118         if (r < 0) {
 119                 log_error("Failed to change runlevel: %s", bus_error_message(&error, -r));
 120                 return;
 121         }
 122 }
 123
 124 static void request_process(Server *s, const struct init_request *req) {
 125         assert(s);
 126         assert(req);
 127
 128         if (req->magic != INIT_MAGIC) {
 129                 log_error("Got initctl request with invalid magic. Ignoring.");
 130                 return;
 131         }
 132
 133         switch (req->cmd) {
 134
 135         case INIT_CMD_RUNLVL:
 136                 if (!isprint(req->runlevel))
 137                         log_error("Got invalid runlevel. Ignoring.");
 138                 else
 139                         switch (req->runlevel) {
 140
 141                         /* we are async anyway, so just use kill for reexec/reload */
 142                         case 'u':
 143                         case 'U':
 144                                 if (kill(1, SIGTERM) < 0)
 145                                         log_error_errno(errno, "kill() failed: %m");
 146
 147                                 /* The bus connection will be
 148                                  * terminated if PID 1 is reexecuted,
 149                                  * hence let's just exit here, and
 150                                  * rely on that we'll be restarted on
 151                                  * the next request */
 152                                 s->quit = true;
 153                                 break;
 154
 155                         case 'q':
 156                         case 'Q':
 157                                 if (kill(1, SIGHUP) < 0)
 158                                         log_error_errno(errno, "kill() failed: %m");
 159                                 break;
 160
 161                         default:
 162                                 change_runlevel(s, req->runlevel);
 163                         }
 164                 return;
 165
 166         case INIT_CMD_POWERFAIL:
 167         case INIT_CMD_POWERFAILNOW:
 168         case INIT_CMD_POWEROK:
 169                 log_warning("Received UPS/power initctl request. This is not implemented in systemd. Upgrade your UPS daemon!");
 170                 return;
 171
 172         case INIT_CMD_CHANGECONS:
 173                 log_warning("Received console change initctl request. This is not implemented in systemd.");
 174                 return;
 175
 176         case INIT_CMD_SETENV:
 177         case INIT_CMD_UNSETENV:
 178                 log_warning("Received environment initctl request. This is not implemented in systemd.");
 179                 return;
 180
 181         default:
 182                 log_warning("Received unknown initctl request. Ignoring.");
 183                 return;
 184         }
 185 }
 186
 187 static int fifo_process(Fifo *f) {
 188         ssize_t l;
 189
 190         assert(f);
 191
 192         errno = EIO;
 193         l = read(f->fd,
 194                  ((uint8_t*) &f->buffer) + f->bytes_read,
 195                  sizeof(f->buffer) - f->bytes_read);
 196         if (l <= 0) {
 197                 if (errno == EAGAIN)
 198                         return 0;
 199
 200                 return log_warning_errno(errno, "Failed to read from fifo: %m");
 201         }
 202
 203         f->bytes_read += l;
 204         assert(f->bytes_read <= sizeof(f->buffer));
 205
 206         if (f->bytes_read == sizeof(f->buffer)) {
 207                 request_process(f->server, &f->buffer);
 208                 f->bytes_read = 0;
 209         }
 210
 211         return 0;
 212 }
 213
 214 static void fifo_free(Fifo *f) {
 215         assert(f);
 216
 217         if (f->server) {
 218                 assert(f->server->n_fifos > 0);
 219                 f->server->n_fifos--;
 220                 LIST_REMOVE(fifo, f->server->fifos, f);
 221         }
 222
 223         if (f->fd >= 0) {
 224                 if (f->server)
 225                         epoll_ctl(f->server->epoll_fd, EPOLL_CTL_DEL, f->fd, NULL);
 226
 227                 safe_close(f->fd);
 228         }
 229
 230         free(f);
 231 }
 232
 233 static void server_done(Server *s) {
 234         assert(s);
 235
 236         while (s->fifos)
 237                 fifo_free(s->fifos);
 238
 239         safe_close(s->epoll_fd);
 240
 241         if (s->bus) {
 242                 sd_bus_flush(s->bus);
 243                 sd_bus_unref(s->bus);
 244         }
 245 }
 246
 247 static int server_init(Server *s, unsigned n_sockets) {
 248         int r;
 249         unsigned i;
 250
 251         assert(s);
 252         assert(n_sockets > 0);
 253
 254         zero(*s);
 255
 256         s->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
 257         if (s->epoll_fd < 0) {
 258                 r = log_error_errno(errno,
 259                                     "Failed to create epoll object: %m");
 260                 goto fail;
 261         }
 262
 263         for (i = 0; i < n_sockets; i++) {
 264                 struct epoll_event ev;
 265                 Fifo *f;
 266                 int fd;
 267
 268                 fd = SD_LISTEN_FDS_START+i;
 269
 270                 r = sd_is_fifo(fd, NULL);
 271                 if (r < 0) {
 272                         log_error_errno(r, "Failed to determine file descriptor type: %m");
 273                         goto fail;
 274                 }
 275
 276                 if (!r) {
 277                         log_error("Wrong file descriptor type.");
 278                         r = -EINVAL;
 279                         goto fail;
 280                 }
 281
 282                 f = new0(Fifo, 1);
 283                 if (!f) {
 284                         r = -ENOMEM;
 285                         log_error_errno(errno, "Failed to create fifo object: %m");
 286                         goto fail;
 287                 }
 288
 289                 f->fd = -1;
 290
 291                 zero(ev);
 292                 ev.events = EPOLLIN;
 293                 ev.data.ptr = f;
 294                 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
 295                         r = -errno;
 296                         fifo_free(f);
 297                         log_error_errno(errno, "Failed to add fifo fd to epoll object: %m");
 298                         goto fail;
 299                 }
 300
 301                 f->fd = fd;
 302                 LIST_PREPEND(fifo, s->fifos, f);
 303                 f->server = s;
 304                 s->n_fifos++;
 305         }
 306
 307         r = bus_connect_system_systemd(&s->bus);
 308         if (r < 0) {
 309                 log_error_errno(r, "Failed to get D-Bus connection: %m");
 310                 r = -EIO;
 311                 goto fail;
 312         }
 313
 314         return 0;
 315
 316 fail:
 317         server_done(s);
 318
 319         return r;
 320 }
 321
 322 static int process_event(Server *s, struct epoll_event *ev) {
 323         int r;
 324         Fifo *f;
 325
 326         assert(s);
 327
 328         if (!(ev->events & EPOLLIN)) {
 329                 log_info("Got invalid event from epoll. (3)");
 330                 return -EIO;
 331         }
 332
 333         f = (Fifo*) ev->data.ptr;
 334         r = fifo_process(f);
 335         if (r < 0) {
 336                 log_info_errno(r, "Got error on fifo: %m");
 337                 fifo_free(f);
 338                 return r;
 339         }
 340
 341         return 0;
 342 }
 343
 344 int main(int argc, char *argv[]) {
 345         Server server;
 346         int r = EXIT_FAILURE, n;
 347
 348         if (getppid() != 1) {
 349                 log_error("This program should be invoked by init only.");
 350                 return EXIT_FAILURE;
 351         }
 352
 353         if (argc > 1) {
 354                 log_error("This program does not take arguments.");
 355                 return EXIT_FAILURE;
 356         }
 357
 358         log_set_target(LOG_TARGET_AUTO);
 359         log_parse_environment();
 360         log_open();
 361
 362         umask(0022);
 363
 364         n = sd_listen_fds(true);
 365         if (n < 0) {
 366                 log_error_errno(r, "Failed to read listening file descriptors from environment: %m");
 367                 return EXIT_FAILURE;
 368         }
 369
 370         if (n <= 0 || n > SERVER_FD_MAX) {
 371                 log_error("No or too many file descriptors passed.");
 372                 return EXIT_FAILURE;
 373         }
 374
 375         if (server_init(&server, (unsigned) n) < 0)
 376                 return EXIT_FAILURE;
 377
 378         log_debug("systemd-initctl running as pid "PID_FMT, getpid_cached());
 379
 380         sd_notify(false,
 381                   "READY=1\n"
 382                   "STATUS=Processing requests...");
 383
 384         while (!server.quit) {
 385                 struct epoll_event event;
 386                 int k;
 387
 388                 k = epoll_wait(server.epoll_fd, &event, 1, TIMEOUT_MSEC);
 389                 if (k < 0) {
 390                         if (errno == EINTR)
 391                                 continue;
 392                         log_error_errno(errno, "epoll_wait() failed: %m");
 393                         goto fail;
 394                 }
 395
 396                 if (k <= 0)
 397                         break;
 398
 399                 if (process_event(&server, &event) < 0)
 400                         goto fail;
 401         }
 402
 403         r = EXIT_SUCCESS;
 404
 405         log_debug("systemd-initctl stopped as pid "PID_FMT, getpid_cached());
 406
 407 fail:
 408         sd_notify(false,
 409                   "STOPPING=1\n"
 410                   "STATUS=Shutting down...");
 411
 412         server_done(&server);
 413
 414         return r;
 415 }