src/initctl.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/socket.h>
  23 #include <sys/types.h>
  24 #include <assert.h>
  25 #include <time.h>
  26 #include <string.h>
  27 #include <stdio.h>
  28 #include <errno.h>
  29 #include <unistd.h>
  30 #include <sys/poll.h>
  31 #include <sys/epoll.h>
  32 #include <sys/un.h>
  33 #include <fcntl.h>
  34 #include <ctype.h>
  35
  36 #include <dbus/dbus.h>
  37 #include <systemd/sd-daemon.h>
  38
  39 #include "util.h"
  40 #include "log.h"
  41 #include "list.h"
  42 #include "initreq.h"
  43 #include "special.h"
  44 #include "dbus-common.h"
  45 #include "def.h"
  46
  47 #define SERVER_FD_MAX 16
  48 #define TIMEOUT_MSEC ((int) (DEFAULT_EXIT_USEC/USEC_PER_MSEC))
  49
  50 typedef struct Fifo Fifo;
  51
  52 typedef struct Server {
  53         int epoll_fd;
  54
  55         LIST_HEAD(Fifo, fifos);
  56         unsigned n_fifos;
  57
  58         DBusConnection *bus;
  59
  60         bool quit;
  61 } Server;
  62
  63 struct Fifo {
  64         Server *server;
  65
  66         int fd;
  67
  68         struct init_request buffer;
  69         size_t bytes_read;
  70
  71         LIST_FIELDS(Fifo, fifo);
  72 };
  73
  74 static const char *translate_runlevel(int runlevel, bool *isolate) {
  75         static const struct {
  76                 const int runlevel;
  77                 const char *special;
  78                 bool isolate;
  79         } table[] = {
  80                 { '0', SPECIAL_POWEROFF_TARGET,  false },
  81                 { '1', SPECIAL_RESCUE_TARGET,    true  },
  82                 { 's', SPECIAL_RESCUE_TARGET,    true  },
  83                 { 'S', SPECIAL_RESCUE_TARGET,    true  },
  84                 { '2', SPECIAL_RUNLEVEL2_TARGET, true  },
  85                 { '3', SPECIAL_RUNLEVEL3_TARGET, true  },
  86                 { '4', SPECIAL_RUNLEVEL4_TARGET, true  },
  87                 { '5', SPECIAL_RUNLEVEL5_TARGET, true  },
  88                 { '6', SPECIAL_REBOOT_TARGET,    false },
  89         };
  90
  91         unsigned i;
  92
  93         assert(isolate);
  94
  95         for (i = 0; i < ELEMENTSOF(table); i++)
  96                 if (table[i].runlevel == runlevel) {
  97                         *isolate = table[i].isolate;
  98                         if (runlevel == '6' && kexec_loaded())
  99                                 return SPECIAL_KEXEC_TARGET;
 100                         return table[i].special;
 101                 }
 102
 103         return NULL;
 104 }
 105
 106 static void change_runlevel(Server *s, int runlevel) {
 107         const char *target;
 108         DBusMessage *m = NULL, *reply = NULL;
 109         DBusError error;
 110         const char *mode;
 111         bool isolate = false;
 112
 113         assert(s);
 114
 115         dbus_error_init(&error);
 116
 117         if (!(target = translate_runlevel(runlevel, &isolate))) {
 118                 log_warning("Got request for unknown runlevel %c, ignoring.", runlevel);
 119                 goto finish;
 120         }
 121
 122         if (isolate)
 123                 mode = "isolate";
 124         else
 125                 mode = "replace";
 126
 127         log_debug("Running request %s/start/%s", target, mode);
 128
 129         if (!(m = dbus_message_new_method_call("org.freedesktop.systemd1", "/org/freedesktop/systemd1", "org.freedesktop.systemd1.Manager", "StartUnit"))) {
 130                 log_error("Could not allocate message.");
 131                 goto finish;
 132         }
 133
 134         if (!dbus_message_append_args(m,
 135                                       DBUS_TYPE_STRING, &target,
 136                                       DBUS_TYPE_STRING, &mode,
 137                                       DBUS_TYPE_INVALID)) {
 138                 log_error("Could not attach target and flag information to message.");
 139                 goto finish;
 140         }
 141
 142         if (!(reply = dbus_connection_send_with_reply_and_block(s->bus, m, -1, &error))) {
 143                 log_error("Failed to start unit: %s", bus_error_message(&error));
 144                 goto finish;
 145         }
 146
 147 finish:
 148         if (m)
 149                 dbus_message_unref(m);
 150
 151         if (reply)
 152                 dbus_message_unref(reply);
 153
 154         dbus_error_free(&error);
 155 }
 156
 157 static void request_process(Server *s, const struct init_request *req) {
 158         assert(s);
 159         assert(req);
 160
 161         if (req->magic != INIT_MAGIC) {
 162                 log_error("Got initctl request with invalid magic. Ignoring.");
 163                 return;
 164         }
 165
 166         switch (req->cmd) {
 167
 168         case INIT_CMD_RUNLVL:
 169                 if (!isprint(req->runlevel))
 170                         log_error("Got invalid runlevel. Ignoring.");
 171                 else
 172                         switch (req->runlevel) {
 173
 174                         /* we are async anyway, so just use kill for reexec/reload */
 175                         case 'u':
 176                         case 'U':
 177                                 if (kill(1, SIGTERM) < 0)
 178                                         log_error("kill() failed: %m");
 179
 180                                 /* The bus connection will be
 181                                  * terminated if PID 1 is reexecuted,
 182                                  * hence let's just exit here, and
 183                                  * rely on that we'll be restarted on
 184                                  * the next request */
 185                                 s->quit = true;
 186                                 break;
 187
 188                         case 'q':
 189                         case 'Q':
 190                                 if (kill(1, SIGHUP) < 0)
 191                                         log_error("kill() failed: %m");
 192                                 break;
 193
 194                         default:
 195                                 change_runlevel(s, req->runlevel);
 196                         }
 197                 return;
 198
 199         case INIT_CMD_POWERFAIL:
 200         case INIT_CMD_POWERFAILNOW:
 201         case INIT_CMD_POWEROK:
 202                 log_warning("Received UPS/power initctl request. This is not implemented in systemd. Upgrade your UPS daemon!");
 203                 return;
 204
 205         case INIT_CMD_CHANGECONS:
 206                 log_warning("Received console change initctl request. This is not implemented in systemd.");
 207                 return;
 208
 209         case INIT_CMD_SETENV:
 210         case INIT_CMD_UNSETENV:
 211                 log_warning("Received environment initctl request. This is not implemented in systemd.");
 212                 return;
 213
 214         default:
 215                 log_warning("Received unknown initctl request. Ignoring.");
 216                 return;
 217         }
 218 }
 219
 220 static int fifo_process(Fifo *f) {
 221         ssize_t l;
 222
 223         assert(f);
 224
 225         errno = EIO;
 226         if ((l = read(f->fd, ((uint8_t*) &f->buffer) + f->bytes_read, sizeof(f->buffer) - f->bytes_read)) <= 0) {
 227
 228                 if (errno == EAGAIN)
 229                         return 0;
 230
 231                 log_warning("Failed to read from fifo: %s", strerror(errno));
 232                 return -1;
 233         }
 234
 235         f->bytes_read += l;
 236         assert(f->bytes_read <= sizeof(f->buffer));
 237
 238         if (f->bytes_read == sizeof(f->buffer)) {
 239                 request_process(f->server, &f->buffer);
 240                 f->bytes_read = 0;
 241         }
 242
 243         return 0;
 244 }
 245
 246 static void fifo_free(Fifo *f) {
 247         assert(f);
 248
 249         if (f->server) {
 250                 assert(f->server->n_fifos > 0);
 251                 f->server->n_fifos--;
 252                 LIST_REMOVE(Fifo, fifo, f->server->fifos, f);
 253         }
 254
 255         if (f->fd >= 0) {
 256                 if (f->server)
 257                         epoll_ctl(f->server->epoll_fd, EPOLL_CTL_DEL, f->fd, NULL);
 258
 259                 close_nointr_nofail(f->fd);
 260         }
 261
 262         free(f);
 263 }
 264
 265 static void server_done(Server *s) {
 266         assert(s);
 267
 268         while (s->fifos)
 269                 fifo_free(s->fifos);
 270
 271         if (s->epoll_fd >= 0)
 272                 close_nointr_nofail(s->epoll_fd);
 273
 274         if (s->bus) {
 275                 dbus_connection_flush(s->bus);
 276                 dbus_connection_close(s->bus);
 277                 dbus_connection_unref(s->bus);
 278         }
 279 }
 280
 281 static int server_init(Server *s, unsigned n_sockets) {
 282         int r;
 283         unsigned i;
 284         DBusError error;
 285
 286         assert(s);
 287         assert(n_sockets > 0);
 288
 289         dbus_error_init(&error);
 290
 291         zero(*s);
 292
 293         if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) {
 294                 r = -errno;
 295                 log_error("Failed to create epoll object: %s", strerror(errno));
 296                 goto fail;
 297         }
 298
 299         for (i = 0; i < n_sockets; i++) {
 300                 struct epoll_event ev;
 301                 Fifo *f;
 302                 int fd;
 303
 304                 fd = SD_LISTEN_FDS_START+i;
 305
 306                 if ((r = sd_is_fifo(fd, NULL)) < 0) {
 307                         log_error("Failed to determine file descriptor type: %s", strerror(-r));
 308                         goto fail;
 309                 }
 310
 311                 if (!r) {
 312                         log_error("Wrong file descriptor type.");
 313                         r = -EINVAL;
 314                         goto fail;
 315                 }
 316
 317                 if (!(f = new0(Fifo, 1))) {
 318                         r = -ENOMEM;
 319                         log_error("Failed to create fifo object: %s", strerror(errno));
 320                         goto fail;
 321                 }
 322
 323                 f->fd = -1;
 324
 325                 zero(ev);
 326                 ev.events = EPOLLIN;
 327                 ev.data.ptr = f;
 328                 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
 329                         r = -errno;
 330                         fifo_free(f);
 331                         log_error("Failed to add fifo fd to epoll object: %s", strerror(errno));
 332                         goto fail;
 333                 }
 334
 335                 f->fd = fd;
 336                 LIST_PREPEND(Fifo, fifo, s->fifos, f);
 337                 f->server = s;
 338                 s->n_fifos ++;
 339         }
 340
 341         if (bus_connect(DBUS_BUS_SYSTEM, &s->bus, NULL, &error) < 0) {
 342                 log_error("Failed to get D-Bus connection: %s", bus_error_message(&error));
 343                 goto fail;
 344         }
 345
 346         return 0;
 347
 348 fail:
 349         server_done(s);
 350
 351         dbus_error_free(&error);
 352         return r;
 353 }
 354
 355 static int process_event(Server *s, struct epoll_event *ev) {
 356         int r;
 357         Fifo *f;
 358
 359         assert(s);
 360
 361         if (!(ev->events & EPOLLIN)) {
 362                 log_info("Got invalid event from epoll. (3)");
 363                 return -EIO;
 364         }
 365
 366         f = (Fifo*) ev->data.ptr;
 367
 368         if ((r = fifo_process(f)) < 0) {
 369                 log_info("Got error on fifo: %s", strerror(-r));
 370                 fifo_free(f);
 371                 return r;
 372         }
 373
 374         return 0;
 375 }
 376
 377 int main(int argc, char *argv[]) {
 378         Server server;
 379         int r = EXIT_FAILURE, n;
 380
 381         if (getppid() != 1) {
 382                 log_error("This program should be invoked by init only.");
 383                 return EXIT_FAILURE;
 384         }
 385
 386         if (argc > 1) {
 387                 log_error("This program does not take arguments.");
 388                 return EXIT_FAILURE;
 389         }
 390
 391         log_set_target(LOG_TARGET_AUTO);
 392         log_parse_environment();
 393         log_open();
 394
 395         umask(0022);
 396
 397         if ((n = sd_listen_fds(true)) < 0) {
 398                 log_error("Failed to read listening file descriptors from environment: %s", strerror(-r));
 399                 return EXIT_FAILURE;
 400         }
 401
 402         if (n <= 0 || n > SERVER_FD_MAX) {
 403                 log_error("No or too many file descriptors passed.");
 404                 return EXIT_FAILURE;
 405         }
 406
 407         if (server_init(&server, (unsigned) n) < 0)
 408                 return EXIT_FAILURE;
 409
 410         log_debug("systemd-initctl running as pid %lu", (unsigned long) getpid());
 411
 412         sd_notify(false,
 413                   "READY=1\n"
 414                   "STATUS=Processing requests...");
 415
 416         while (!server.quit) {
 417                 struct epoll_event event;
 418                 int k;
 419
 420                 if ((k = epoll_wait(server.epoll_fd,
 421                                     &event, 1,
 422                                     TIMEOUT_MSEC)) < 0) {
 423
 424                         if (errno == EINTR)
 425                                 continue;
 426
 427                         log_error("epoll_wait() failed: %s", strerror(errno));
 428                         goto fail;
 429                 }
 430
 431                 if (k <= 0)
 432                         break;
 433
 434                 if (process_event(&server, &event) < 0)
 435                         goto fail;
 436         }
 437
 438         r = EXIT_SUCCESS;
 439
 440         log_debug("systemd-initctl stopped as pid %lu", (unsigned long) getpid());
 441
 442 fail:
 443         sd_notify(false,
 444                   "STATUS=Shutting down...");
 445
 446         server_done(&server);
 447
 448         dbus_shutdown();
 449
 450         return r;
 451 }