initctl.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   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 General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU 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
  38 #include "util.h"
  39 #include "log.h"
  40 #include "list.h"
  41 #include "initreq.h"
  42 #include "manager.h"
  43
  44 #define SERVER_FD_START 3
  45 #define SERVER_FD_MAX 16
  46 #define TIMEOUT ((int) (10*MSEC_PER_SEC))
  47
  48 typedef struct Fifo Fifo;
  49
  50 typedef struct Server {
  51         int epoll_fd;
  52
  53         LIST_HEAD(Fifo, fifos);
  54         unsigned n_fifos;
  55
  56         DBusConnection *bus;
  57 } Server;
  58
  59 struct Fifo {
  60         Server *server;
  61
  62         int fd;
  63
  64         struct init_request buffer;
  65         size_t bytes_read;
  66
  67         LIST_FIELDS(Fifo, fifo);
  68 };
  69
  70 static const char *translate_runlevel(int runlevel) {
  71         static const struct {
  72                 const int runlevel;
  73                 const char *special;
  74         } table[] = {
  75                 { '0', SPECIAL_RUNLEVEL0_TARGET },
  76                 { '1', SPECIAL_RUNLEVEL1_TARGET },
  77                 { 's', SPECIAL_RUNLEVEL1_TARGET },
  78                 { 'S', SPECIAL_RUNLEVEL1_TARGET },
  79                 { '2', SPECIAL_RUNLEVEL2_TARGET },
  80                 { '3', SPECIAL_RUNLEVEL3_TARGET },
  81                 { '4', SPECIAL_RUNLEVEL4_TARGET },
  82                 { '5', SPECIAL_RUNLEVEL5_TARGET },
  83                 { '6', SPECIAL_RUNLEVEL6_TARGET },
  84         };
  85
  86         unsigned i;
  87
  88         for (i = 0; i < ELEMENTSOF(table); i++)
  89                 if (table[i].runlevel == runlevel)
  90                         return table[i].special;
  91
  92         return NULL;
  93 }
  94
  95 static void change_runlevel(Server *s, int runlevel) {
  96         const char *target;
  97         DBusMessage *m = NULL, *reply = NULL;
  98         DBusError error;
  99         const char *path, *replace = "isolate";
 100
 101         assert(s);
 102
 103         dbus_error_init(&error);
 104
 105         if (!(target = translate_runlevel(runlevel))) {
 106                 log_warning("Got request for unknown runlevel %c, ignoring.", runlevel);
 107                 goto finish;
 108         }
 109
 110         log_debug("Running request %s", target);
 111
 112         if (!(m = dbus_message_new_method_call("org.freedesktop.systemd1", "/org/freedesktop/systemd1", "org.freedesktop.systemd1.Manager", "LoadUnit"))) {
 113                 log_error("Could not allocate message.");
 114                 goto finish;
 115         }
 116
 117         if (!dbus_message_append_args(m,
 118                                       DBUS_TYPE_STRING, &target,
 119                                       DBUS_TYPE_INVALID)) {
 120                 log_error("Could not attach group information to signal message.");
 121                 goto finish;
 122         }
 123
 124         if (!(reply = dbus_connection_send_with_reply_and_block(s->bus, m, -1, &error))) {
 125                 log_error("Failed to get unit path: %s", error.message);
 126                 goto finish;
 127         }
 128
 129         if (!dbus_message_get_args(reply, &error,
 130                                    DBUS_TYPE_OBJECT_PATH, &path,
 131                                    DBUS_TYPE_INVALID)) {
 132                 log_error("Failed to parse unit path: %s", error.message);
 133                 goto finish;
 134         }
 135
 136         dbus_message_unref(m);
 137         if (!(m = dbus_message_new_method_call("org.freedesktop.systemd1", path, "org.freedesktop.systemd1.Unit", "Start"))) {
 138                 log_error("Could not allocate message.");
 139                 goto finish;
 140         }
 141
 142         if (!dbus_message_append_args(m,
 143                                       DBUS_TYPE_STRING, &replace,
 144                                       DBUS_TYPE_INVALID)) {
 145                 log_error("Could not attach group information to signal message.");
 146                 goto finish;
 147         }
 148
 149         dbus_message_unref(reply);
 150         if (!(reply = dbus_connection_send_with_reply_and_block(s->bus, m, -1, &error))) {
 151                 log_error("Failed to start unit: %s", error.message);
 152                 goto finish;
 153         }
 154
 155 finish:
 156         if (m)
 157                 dbus_message_unref(m);
 158
 159         if (reply)
 160                 dbus_message_unref(reply);
 161
 162         dbus_error_free(&error);
 163 }
 164
 165 static void request_process(Server *s, const struct init_request *req) {
 166         assert(s);
 167         assert(req);
 168
 169         if (req->magic != INIT_MAGIC) {
 170                 log_error("Got initctl request with invalid magic. Ignoring.");
 171                 return;
 172         }
 173
 174         switch (req->cmd) {
 175
 176         case INIT_CMD_RUNLVL:
 177                 if (!isprint(req->runlevel))
 178                         log_error("Got invalid runlevel. Ignoring.");
 179                 else
 180                         change_runlevel(s, req->runlevel);
 181                 return;
 182
 183         case INIT_CMD_POWERFAIL:
 184         case INIT_CMD_POWERFAILNOW:
 185         case INIT_CMD_POWEROK:
 186                 log_warning("Received UPS/power initctl request. This is not implemented in systemd. Upgrade your UPS daemon!");
 187                 return;
 188
 189         case INIT_CMD_CHANGECONS:
 190                 log_warning("Received console change initctl request. This is not implemented in systemd.");
 191                 return;
 192
 193         case INIT_CMD_SETENV:
 194         case INIT_CMD_UNSETENV:
 195                 log_warning("Received environment initctl request. This is not implemented in systemd.");
 196                 return;
 197
 198         default:
 199                 log_warning("Received unknown initctl request. Ignoring.");
 200                 return;
 201         }
 202 }
 203
 204 static int fifo_process(Fifo *f) {
 205         ssize_t l;
 206
 207         assert(f);
 208
 209         errno = EIO;
 210         if ((l = read(f->fd, ((uint8_t*) &f->buffer) + f->bytes_read, sizeof(f->buffer) - f->bytes_read)) <= 0) {
 211
 212                 if (errno == EAGAIN)
 213                         return 0;
 214
 215                 log_warning("Failed to read from fifo: %s", strerror(errno));
 216                 return -1;
 217         }
 218
 219         f->bytes_read += l;
 220         assert(f->bytes_read <= sizeof(f->buffer));
 221
 222         if (f->bytes_read == sizeof(f->buffer)) {
 223                 request_process(f->server, &f->buffer);
 224                 f->bytes_read = 0;
 225         }
 226
 227         return 0;
 228 }
 229
 230 static void fifo_free(Fifo *f) {
 231         assert(f);
 232
 233         if (f->server) {
 234                 assert(f->server->n_fifos > 0);
 235                 f->server->n_fifos--;
 236                 LIST_REMOVE(Fifo, fifo, f->server->fifos, f);
 237         }
 238
 239         if (f->fd >= 0) {
 240                 if (f->server)
 241                         epoll_ctl(f->server->epoll_fd, EPOLL_CTL_DEL, f->fd, NULL);
 242
 243                 close_nointr_nofail(f->fd);
 244         }
 245
 246         free(f);
 247 }
 248
 249 static int verify_environment(unsigned *n_sockets) {
 250         unsigned long long pid;
 251         const char *e;
 252         int r;
 253         unsigned ns;
 254
 255         assert_se(n_sockets);
 256
 257         if (!(e = getenv("LISTEN_PID"))) {
 258                 log_error("Missing $LISTEN_PID environment variable.");
 259                 return -ENOENT;
 260         }
 261
 262         if ((r = safe_atollu(e, &pid)) < 0) {
 263                 log_error("Failed to parse $LISTEN_PID: %s", strerror(-r));
 264                 return r;
 265         }
 266
 267         if (pid != (unsigned long long) getpid()) {
 268                 log_error("Socket nor for me.");
 269                 return -ENOENT;
 270         }
 271
 272         if (!(e = getenv("LISTEN_FDS"))) {
 273                 log_error("Missing $LISTEN_FDS environment variable.");
 274                 return -ENOENT;
 275         }
 276
 277         if ((r = safe_atou(e, &ns)) < 0) {
 278                 log_error("Failed to parse $LISTEN_FDS: %s", strerror(-r));
 279                 return -E2BIG;
 280         }
 281
 282         if (ns <= 0 || ns > SERVER_FD_MAX) {
 283                 log_error("Wrong number of file descriptors passed: %s", e);
 284                 return -E2BIG;
 285         }
 286
 287         *n_sockets = ns;
 288
 289         return 0;
 290 }
 291
 292 static void server_done(Server *s) {
 293         assert(s);
 294
 295         while (s->fifos)
 296                 fifo_free(s->fifos);
 297
 298         if (s->epoll_fd >= 0)
 299                 close_nointr_nofail(s->epoll_fd);
 300
 301         if (s->bus)
 302                 dbus_connection_unref(s->bus);
 303 }
 304
 305 static int server_init(Server *s, unsigned n_sockets) {
 306         int r;
 307         unsigned i;
 308         DBusError error;
 309
 310         assert(s);
 311         assert(n_sockets > 0);
 312
 313         dbus_error_init(&error);
 314
 315         zero(*s);
 316
 317         if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) {
 318                 r = -errno;
 319                 log_error("Failed to create epoll object: %s", strerror(errno));
 320                 goto fail;
 321         }
 322
 323         for (i = 0; i < n_sockets; i++) {
 324                 struct epoll_event ev;
 325                 Fifo *f;
 326
 327                 if (!(f = new0(Fifo, 1))) {
 328                         r = -ENOMEM;
 329                         log_error("Failed to create fifo object: %s", strerror(errno));
 330                         goto fail;
 331                 }
 332
 333                 f->fd = -1;
 334
 335                 zero(ev);
 336                 ev.events = EPOLLIN;
 337                 ev.data.ptr = f;
 338                 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, SERVER_FD_START+i, &ev) < 0) {
 339                         r = -errno;
 340                         fifo_free(f);
 341                         log_error("Failed to add fifo fd to epoll object: %s", strerror(errno));
 342                         goto fail;
 343                 }
 344
 345                 f->fd = SERVER_FD_START+i;
 346                 LIST_PREPEND(Fifo, fifo, s->fifos, f);
 347                 f->server = s;
 348                 s->n_fifos ++;
 349         }
 350
 351         if (!(s->bus = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
 352                 log_error("Failed to get D-Bus connection: %s", error.message);
 353                 goto fail;
 354         }
 355
 356         return 0;
 357
 358 fail:
 359         server_done(s);
 360
 361         dbus_error_free(&error);
 362         return r;
 363 }
 364
 365 static int process_event(Server *s, struct epoll_event *ev) {
 366         int r;
 367         Fifo *f;
 368
 369         assert(s);
 370
 371         if (!(ev->events & EPOLLIN)) {
 372                 log_info("Got invalid event from epoll. (3)");
 373                 return -EIO;
 374         }
 375
 376         f = (Fifo*) ev->data.ptr;
 377
 378         if ((r = fifo_process(f)) < 0) {
 379                 log_info("Got error on fifo: %s", strerror(-r));
 380                 fifo_free(f);
 381                 return r;
 382         }
 383
 384         return 0;
 385 }
 386
 387 int main(int argc, char *argv[]) {
 388         Server server;
 389         int r = 3;
 390         unsigned n;
 391
 392         log_info("systemd-initctl running as pid %llu", (unsigned long long) getpid());
 393
 394         if (verify_environment(&n) < 0)
 395                 return 1;
 396
 397         if (server_init(&server, n) < 0)
 398                 return 2;
 399
 400         for (;;) {
 401                 struct epoll_event event;
 402                 int k;
 403
 404                 if ((k = epoll_wait(server.epoll_fd,
 405                                     &event, 1,
 406                                     TIMEOUT)) < 0) {
 407
 408                         if (errno == EINTR)
 409                                 continue;
 410
 411                         log_error("epoll_wait() failed: %s", strerror(errno));
 412                         goto fail;
 413                 }
 414
 415                 if (k <= 0)
 416                         break;
 417
 418                 if ((k = process_event(&server, &event)) < 0)
 419                         goto fail;
 420         }
 421         r = 0;
 422
 423 fail:
 424         server_done(&server);
 425
 426         log_info("systemd-initctl stopped as pid %llu", (unsigned long long) getpid());
 427
 428         dbus_shutdown();
 429
 430         return r;
 431 }