src/initctl/initctl.c

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