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 "constants.h"
  18 #include "daemon-util.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 "reboot-util.h"
  28 #include "special.h"
  29
  30 #define SERVER_FD_MAX 16
  31 #define TIMEOUT_MSEC ((int) (DEFAULT_EXIT_USEC/USEC_PER_MSEC))
  32
  33 typedef struct Fifo Fifo;
  34
  35 typedef struct Server {
  36         int epoll_fd;
  37
  38         LIST_HEAD(Fifo, fifos);
  39         unsigned n_fifos;
  40
  41         sd_bus *bus;
  42
  43         bool quit;
  44 } Server;
  45
  46 struct Fifo {
  47         Server *server;
  48
  49         int fd;
  50
  51         struct init_request buffer;
  52         size_t bytes_read;
  53
  54         LIST_FIELDS(Fifo, fifo);
  55 };
  56
  57 static const char *translate_runlevel(int runlevel, bool *isolate) {
  58         static const struct {
  59                 const int runlevel;
  60                 const char *special;
  61                 bool isolate;
  62         } table[] = {
  63                 { '0', SPECIAL_POWEROFF_TARGET,   false },
  64                 { '1', SPECIAL_RESCUE_TARGET,     true  },
  65                 { 's', SPECIAL_RESCUE_TARGET,     true  },
  66                 { 'S', SPECIAL_RESCUE_TARGET,     true  },
  67                 { '2', SPECIAL_MULTI_USER_TARGET, true  },
  68                 { '3', SPECIAL_MULTI_USER_TARGET, true  },
  69                 { '4', SPECIAL_MULTI_USER_TARGET, true  },
  70                 { '5', SPECIAL_GRAPHICAL_TARGET,  true  },
  71                 { '6', SPECIAL_REBOOT_TARGET,     false },
  72         };
  73
  74         assert(isolate);
  75
  76         for (size_t 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 int 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 0;
 100         }
 101
 102         if (isolate)
 103                 mode = "isolate";
 104         else
 105                 mode = "replace-irreversibly";
 106
 107         log_debug("Requesting %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                 return log_error_errno(r, "Failed to change runlevel: %s", bus_error_message(&error, r));
 120
 121         return 0;
 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                                 (void) 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 Fifo* fifo_free(Fifo *f) {
 215         if (!f)
 216                 return NULL;
 217
 218         if (f->server) {
 219                 assert(f->server->n_fifos > 0);
 220                 f->server->n_fifos--;
 221                 LIST_REMOVE(fifo, f->server->fifos, f);
 222         }
 223
 224         if (f->fd >= 0) {
 225                 if (f->server)
 226                         (void) epoll_ctl(f->server->epoll_fd, EPOLL_CTL_DEL, f->fd, NULL);
 227
 228                 safe_close(f->fd);
 229         }
 230
 231         return mfree(f);
 232 }
 233 DEFINE_TRIVIAL_CLEANUP_FUNC(Fifo*, fifo_free);
 234
 235 static void server_done(Server *s) {
 236         assert(s);
 237
 238         while (s->fifos)
 239                 fifo_free(s->fifos);
 240
 241         s->epoll_fd = safe_close(s->epoll_fd);
 242         s->bus = sd_bus_flush_close_unref(s->bus);
 243 }
 244
 245 static int server_init(Server *s, unsigned n_sockets) {
 246         int r;
 247
 248         /* This function will leave s partially initialized on failure. Caller needs to clean up. */
 249
 250         assert(s);
 251         assert(n_sockets > 0);
 252
 253         s->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
 254         if (s->epoll_fd < 0)
 255                 return log_error_errno(errno, "Failed to create epoll object: %m");
 256
 257         for (unsigned i = 0; i < n_sockets; i++) {
 258                 _cleanup_(fifo_freep) Fifo *f = NULL;
 259                 int fd = SD_LISTEN_FDS_START + i;
 260
 261                 r = sd_is_fifo(fd, NULL);
 262                 if (r < 0)
 263                         return log_error_errno(r, "Failed to determine file descriptor type: %m");
 264                 if (!r)
 265                         return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Wrong file descriptor type.");
 266
 267                 f = new0(Fifo, 1);
 268                 if (!f)
 269                         return log_oom();
 270
 271                 struct epoll_event ev = {
 272                         .events = EPOLLIN,
 273                         .data.ptr = f,
 274                 };
 275
 276                 if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0)
 277                         return log_error_errno(errno, "Failed to add fifo fd to epoll object: %m");
 278
 279                 f->fd = fd;
 280                 f->server = s;
 281                 LIST_PREPEND(fifo, s->fifos, TAKE_PTR(f));
 282                 s->n_fifos++;
 283         }
 284
 285         r = bus_connect_system_systemd(&s->bus);
 286         if (r < 0)
 287                 return log_error_errno(r, "Failed to get D-Bus connection: %m");
 288
 289         return 0;
 290 }
 291
 292 static int process_event(Server *s, struct epoll_event *ev) {
 293         int r;
 294         Fifo *f;
 295
 296         assert(s);
 297
 298         if (!(ev->events & EPOLLIN))
 299                 return log_info_errno(SYNTHETIC_ERRNO(EIO),
 300                                       "Got invalid event from epoll. (3)");
 301
 302         f = (Fifo*) ev->data.ptr;
 303         r = fifo_process(f);
 304         if (r < 0) {
 305                 log_info_errno(r, "Got error on fifo: %m");
 306                 fifo_free(f);
 307                 return r;
 308         }
 309
 310         return 0;
 311 }
 312
 313 static int run(int argc, char *argv[]) {
 314         _cleanup_(server_done) Server server = { .epoll_fd = -1 };
 315         _unused_ _cleanup_(notify_on_cleanup) const char *notify_stop = NULL;
 316         int r, n;
 317
 318         if (argc > 1)
 319                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 320                                        "This program does not take arguments.");
 321
 322         log_setup();
 323
 324         umask(0022);
 325
 326         n = sd_listen_fds(true);
 327         if (n < 0)
 328                 return log_error_errno(errno,
 329                                        "Failed to read listening file descriptors from environment: %m");
 330
 331         if (n <= 0 || n > SERVER_FD_MAX)
 332                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 333                                        "No or too many file descriptors passed.");
 334
 335         r = server_init(&server, (unsigned) n);
 336         if (r < 0)
 337                 return r;
 338
 339         notify_stop = notify_start(NOTIFY_READY, NOTIFY_STOPPING);
 340
 341         while (!server.quit) {
 342                 struct epoll_event event;
 343                 int k;
 344
 345                 k = epoll_wait(server.epoll_fd, &event, 1, TIMEOUT_MSEC);
 346                 if (k < 0) {
 347                         if (errno == EINTR)
 348                                 continue;
 349                         return log_error_errno(errno, "epoll_wait() failed: %m");
 350                 }
 351                 if (k == 0)
 352                         break;
 353
 354                 r = process_event(&server, &event);
 355                 if (r < 0)
 356                         return r;
 357         }
 358
 359         return 0;
 360 }
 361
 362 DEFINE_MAIN_FUNCTION(run);