summaryrefslogtreecommitdiffstats
path: root/src/initctl/initctl.c
blob: 260dc2eb618b7092d93d298ae76b851a740baf4c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
/* SPDX-License-Identifier: LGPL-2.1+ */

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <sys/epoll.h>
#include <unistd.h>

#include "sd-bus.h"
#include "sd-daemon.h"

#include "alloc-util.h"
#include "bus-error.h"
#include "bus-util.h"
#include "def.h"
#include "fd-util.h"
#include "format-util.h"
#include "initreq.h"
#include "list.h"
#include "log.h"
#include "special.h"
#include "util.h"
#include "process-util.h"

#define SERVER_FD_MAX 16
#define TIMEOUT_MSEC ((int) (DEFAULT_EXIT_USEC/USEC_PER_MSEC))

typedef struct Fifo Fifo;

typedef struct Server {
        int epoll_fd;

        LIST_HEAD(Fifo, fifos);
        unsigned n_fifos;

        sd_bus *bus;

        bool quit;
} Server;

struct Fifo {
        Server *server;

        int fd;

        struct init_request buffer;
        size_t bytes_read;

        LIST_FIELDS(Fifo, fifo);
};

static const char *translate_runlevel(int runlevel, bool *isolate) {
        static const struct {
                const int runlevel;
                const char *special;
                bool isolate;
        } table[] = {
                { '0', SPECIAL_POWEROFF_TARGET,   false },
                { '1', SPECIAL_RESCUE_TARGET,     true  },
                { 's', SPECIAL_RESCUE_TARGET,     true  },
                { 'S', SPECIAL_RESCUE_TARGET,     true  },
                { '2', SPECIAL_MULTI_USER_TARGET, true  },
                { '3', SPECIAL_MULTI_USER_TARGET, true  },
                { '4', SPECIAL_MULTI_USER_TARGET, true  },
                { '5', SPECIAL_GRAPHICAL_TARGET,  true  },
                { '6', SPECIAL_REBOOT_TARGET,     false },
        };

        unsigned i;

        assert(isolate);

        for (i = 0; i < ELEMENTSOF(table); i++)
                if (table[i].runlevel == runlevel) {
                        *isolate = table[i].isolate;
                        if (runlevel == '6' && kexec_loaded())
                                return SPECIAL_KEXEC_TARGET;
                        return table[i].special;
                }

        return NULL;
}

static int change_runlevel(Server *s, int runlevel) {
        const char *target;
        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
        const char *mode;
        bool isolate = false;
        int r;

        assert(s);

        target = translate_runlevel(runlevel, &isolate);
        if (!target) {
                log_warning("Got request for unknown runlevel %c, ignoring.", runlevel);
                return 0;
        }

        if (isolate)
                mode = "isolate";
        else
                mode = "replace-irreversibly";

        log_debug("Running request %s/start/%s", target, mode);

        r = sd_bus_call_method(
                        s->bus,
                        "org.freedesktop.systemd1",
                        "/org/freedesktop/systemd1",
                        "org.freedesktop.systemd1.Manager",
                        "StartUnit",
                        &error,
                        NULL,
                        "ss", target, mode);
        if (r < 0)
                return log_error_errno(r, "Failed to change runlevel: %s", bus_error_message(&error, -r));

        return 0;
}

static void request_process(Server *s, const struct init_request *req) {
        assert(s);
        assert(req);

        if (req->magic != INIT_MAGIC) {
                log_error("Got initctl request with invalid magic. Ignoring.");
                return;
        }

        switch (req->cmd) {

        case INIT_CMD_RUNLVL:
                if (!isprint(req->runlevel))
                        log_error("Got invalid runlevel. Ignoring.");
                else
                        switch (req->runlevel) {

                        /* we are async anyway, so just use kill for reexec/reload */
                        case 'u':
                        case 'U':
                                if (kill(1, SIGTERM) < 0)
                                        log_error_errno(errno, "kill() failed: %m");

                                /* The bus connection will be
                                 * terminated if PID 1 is reexecuted,
                                 * hence let's just exit here, and
                                 * rely on that we'll be restarted on
                                 * the next request */
                                s->quit = true;
                                break;

                        case 'q':
                        case 'Q':
                                if (kill(1, SIGHUP) < 0)
                                        log_error_errno(errno, "kill() failed: %m");
                                break;

                        default:
                                (void) change_runlevel(s, req->runlevel);
                        }
                return;

        case INIT_CMD_POWERFAIL:
        case INIT_CMD_POWERFAILNOW:
        case INIT_CMD_POWEROK:
                log_warning("Received UPS/power initctl request. This is not implemented in systemd. Upgrade your UPS daemon!");
                return;

        case INIT_CMD_CHANGECONS:
                log_warning("Received console change initctl request. This is not implemented in systemd.");
                return;

        case INIT_CMD_SETENV:
        case INIT_CMD_UNSETENV:
                log_warning("Received environment initctl request. This is not implemented in systemd.");
                return;

        default:
                log_warning("Received unknown initctl request. Ignoring.");
                return;
        }
}

static int fifo_process(Fifo *f) {
        ssize_t l;

        assert(f);

        errno = EIO;
        l = read(f->fd,
                 ((uint8_t*) &f->buffer) + f->bytes_read,
                 sizeof(f->buffer) - f->bytes_read);
        if (l <= 0) {
                if (errno == EAGAIN)
                        return 0;

                return log_warning_errno(errno, "Failed to read from fifo: %m");
        }

        f->bytes_read += l;
        assert(f->bytes_read <= sizeof(f->buffer));

        if (f->bytes_read == sizeof(f->buffer)) {
                request_process(f->server, &f->buffer);
                f->bytes_read = 0;
        }

        return 0;
}

static void fifo_free(Fifo *f) {
        assert(f);

        if (f->server) {
                assert(f->server->n_fifos > 0);
                f->server->n_fifos--;
                LIST_REMOVE(fifo, f->server->fifos, f);
        }

        if (f->fd >= 0) {
                if (f->server)
                        epoll_ctl(f->server->epoll_fd, EPOLL_CTL_DEL, f->fd, NULL);

                safe_close(f->fd);
        }

        free(f);
}

static void server_done(Server *s) {
        assert(s);

        while (s->fifos)
                fifo_free(s->fifos);

        s->epoll_fd = safe_close(s->epoll_fd);
        s->bus = sd_bus_flush_close_unref(s->bus);
}

static int server_init(Server *s, unsigned n_sockets) {
        int r;
        unsigned i;

        assert(s);
        assert(n_sockets > 0);

        zero(*s);

        s->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
        if (s->epoll_fd < 0) {
                r = log_error_errno(errno,
                                    "Failed to create epoll object: %m");
                goto fail;
        }

        for (i = 0; i < n_sockets; i++) {
                struct epoll_event ev;
                Fifo *f;
                int fd;

                fd = SD_LISTEN_FDS_START+i;

                r = sd_is_fifo(fd, NULL);
                if (r < 0) {
                        log_error_errno(r, "Failed to determine file descriptor type: %m");
                        goto fail;
                }

                if (!r) {
                        log_error("Wrong file descriptor type.");
                        r = -EINVAL;
                        goto fail;
                }

                f = new0(Fifo, 1);
                if (!f) {
                        r = -ENOMEM;
                        log_error_errno(errno, "Failed to create fifo object: %m");
                        goto fail;
                }

                f->fd = -1;

                zero(ev);
                ev.events = EPOLLIN;
                ev.data.ptr = f;
                if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
                        r = -errno;
                        fifo_free(f);
                        log_error_errno(errno, "Failed to add fifo fd to epoll object: %m");
                        goto fail;
                }

                f->fd = fd;
                LIST_PREPEND(fifo, s->fifos, f);
                f->server = s;
                s->n_fifos++;
        }

        r = bus_connect_system_systemd(&s->bus);
        if (r < 0) {
                log_error_errno(r, "Failed to get D-Bus connection: %m");
                r = -EIO;
                goto fail;
        }

        return 0;

fail:
        server_done(s);

        return r;
}

static int process_event(Server *s, struct epoll_event *ev) {
        int r;
        Fifo *f;

        assert(s);

        if (!(ev->events & EPOLLIN))
                return log_info_errno(SYNTHETIC_ERRNO(EIO),
                                      "Got invalid event from epoll. (3)");

        f = (Fifo*) ev->data.ptr;
        r = fifo_process(f);
        if (r < 0) {
                log_info_errno(r, "Got error on fifo: %m");
                fifo_free(f);
                return r;
        }

        return 0;
}

int main(int argc, char *argv[]) {
        Server server;
        int r = EXIT_FAILURE, n;

        if (getppid() != 1) {
                log_error("This program should be invoked by init only.");
                return EXIT_FAILURE;
        }

        if (argc > 1) {
                log_error("This program does not take arguments.");
                return EXIT_FAILURE;
        }

        log_setup_service();

        umask(0022);

        n = sd_listen_fds(true);
        if (n < 0) {
                log_error_errno(r, "Failed to read listening file descriptors from environment: %m");
                return EXIT_FAILURE;
        }

        if (n <= 0 || n > SERVER_FD_MAX) {
                log_error("No or too many file descriptors passed.");
                return EXIT_FAILURE;
        }

        if (server_init(&server, (unsigned) n) < 0)
                return EXIT_FAILURE;

        log_debug("systemd-initctl running as pid "PID_FMT, getpid_cached());

        sd_notify(false,
                  "READY=1\n"
                  "STATUS=Processing requests...");

        while (!server.quit) {
                struct epoll_event event;
                int k;

                k = epoll_wait(server.epoll_fd, &event, 1, TIMEOUT_MSEC);
                if (k < 0) {
                        if (errno == EINTR)
                                continue;
                        log_error_errno(errno, "epoll_wait() failed: %m");
                        goto fail;
                }

                if (k <= 0)
                        break;

                if (process_event(&server, &event) < 0)
                        goto fail;
        }

        r = EXIT_SUCCESS;

        log_debug("systemd-initctl stopped as pid "PID_FMT, getpid_cached());

fail:
        sd_notify(false,
                  "STOPPING=1\n"
                  "STATUS=Shutting down...");

        server_done(&server);

        return r;
}