summaryrefslogtreecommitdiff
path: root/src/readahead/readahead-replay.c
blob: 88c7a219a8dd5fa04e4ebd353d4818c2883943ea (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
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <inttypes.h>
#include <fcntl.h>
#include <linux/limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <getopt.h>
#include <sys/inotify.h>

#include <systemd/sd-daemon.h>

#include "missing.h"
#include "util.h"
#include "set.h"
#include "ioprio.h"
#include "readahead-common.h"
#include "virt.h"

static off_t arg_file_size_max = READAHEAD_FILE_SIZE_MAX;

static ReadaheadShared *shared = NULL;

static int unpack_file(FILE *pack) {
        char fn[PATH_MAX];
        int r = 0, fd = -1;
        bool any = false;
        struct stat st;

        assert(pack);

        if (!fgets(fn, sizeof(fn), pack))
                return 0;

        char_array_0(fn);
        truncate_nl(fn);

        if ((fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW)) < 0) {

                if (errno != ENOENT && errno != EPERM && errno != EACCES)
                        log_warning("open(%s) failed: %m", fn);

        } else if (file_verify(fd, fn, arg_file_size_max, &st) <= 0) {
                close_nointr_nofail(fd);
                fd = -1;
        }

        for (;;) {
                uint32_t b, c;

                if (fread(&b, sizeof(b), 1, pack) != 1 ||
                    fread(&c, sizeof(c), 1, pack) != 1) {
                        log_error("Premature end of pack file.");
                        r = -EIO;
                        goto finish;
                }

                if (b == 0 && c == 0)
                        break;

                if (c <= b) {
                        log_error("Invalid pack file.");
                        r = -EIO;
                        goto finish;
                }

                log_debug("%s: page %u to %u", fn, b, c);

                any = true;

                if (fd >= 0)
                        if (posix_fadvise(fd, b * page_size(), (c - b) * page_size(), POSIX_FADV_WILLNEED) < 0) {
                                log_warning("posix_fadvise() failed: %m");
                                goto finish;
                        }
        }

        if (!any && fd >= 0) {
                /* if no range is encoded in the pack file this is
                 * intended to mean that the whole file shall be
                 * read */

                if (posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED) < 0) {
                        log_warning("posix_fadvise() failed: %m");
                        goto finish;
                }
        }

finish:
        if (fd >= 0)
                close_nointr_nofail(fd);

        return r;
}

static int replay(const char *root) {
        FILE *pack = NULL;
        char line[LINE_MAX];
        int r = 0;
        char *pack_fn = NULL;
        int c;
        bool on_ssd, ready = false;
        int prio;
        int inotify_fd = -1;

        assert(root);

        write_one_line_file("/proc/self/oom_score_adj", "1000");
        bump_request_nr(root);

        if (asprintf(&pack_fn, "%s/.readahead", root) < 0) {
                log_error("Out of memory");
                r = -ENOMEM;
                goto finish;
        }

        if ((!(pack = fopen(pack_fn, "re")))) {
                if (errno == ENOENT)
                        log_debug("No pack file found.");
                else {
                        log_error("Failed to open pack file: %m");
                        r = -errno;
                }

                goto finish;
        }

        posix_fadvise(fileno(pack), 0, 0, POSIX_FADV_WILLNEED);

        if ((inotify_fd = open_inotify()) < 0) {
                r = inotify_fd;
                goto finish;
        }

        if (!(fgets(line, sizeof(line), pack))) {
                log_error("Premature end of pack file.");
                r = -EIO;
                goto finish;
        }

        char_array_0(line);

        if (!streq(line, CANONICAL_HOST "\n")) {
                log_debug("Pack file host type mismatch.");
                goto finish;
        }

        if ((c = getc(pack)) == EOF) {
                log_debug("Premature end of pack file.");
                r = -EIO;
                goto finish;
        }

        /* We do not retest SSD here, so that we can start replaying
         * before udev is up.*/
        on_ssd = c == 'S';
        log_debug("On SSD: %s", yes_no(on_ssd));

        if (on_ssd)
                prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0);
        else
                prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_RT, 7);

        if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), prio) < 0)
                log_warning("Failed to set IDLE IO priority class: %m");

        sd_notify(0, "STATUS=Replaying readahead data");

        log_debug("Replaying...");

        if (access("/run/systemd/readahead/noreplay", F_OK) >= 0) {
                log_debug("Got termination request");
                goto done;
        }

        while (!feof(pack) && !ferror(pack)) {
                uint8_t inotify_buffer[sizeof(struct inotify_event) + FILENAME_MAX];
                int k;
                ssize_t n;

                if ((n = read(inotify_fd, &inotify_buffer, sizeof(inotify_buffer))) < 0) {
                        if (errno != EINTR && errno != EAGAIN) {
                                log_error("Failed to read inotify event: %m");
                                r = -errno;
                                goto finish;
                        }
                } else {
                        struct inotify_event *e = (struct inotify_event*) inotify_buffer;

                        while (n > 0) {
                                size_t step;

                                if ((e->mask & IN_CREATE) && streq(e->name, "noreplay")) {
                                        log_debug("Got termination request");
                                        goto done;
                                }

                                step = sizeof(struct inotify_event) + e->len;
                                assert(step <= (size_t) n);

                                e = (struct inotify_event*) ((uint8_t*) e + step);
                                n -= step;
                        }
                }

                if ((k = unpack_file(pack)) < 0) {
                        r = k;
                        goto finish;
                }

                if (!ready) {
                        /* We delay the ready notification until we
                         * queued at least one read */
                        sd_notify(0, "READY=1");
                        ready = true;
                }
        }

done:
        if (!ready)
                sd_notify(0, "READY=1");

        if (ferror(pack)) {
                log_error("Failed to read pack file.");
                r = -EIO;
                goto finish;
        }

        log_debug("Done.");

finish:
        if (pack)
                fclose(pack);

        if (inotify_fd >= 0)
                close_nointr_nofail(inotify_fd);

        free(pack_fn);

        return r;
}


static int help(void) {

        printf("%s [OPTIONS...] [DIRECTORY]\n\n"
               "Replay collected read-ahead data on early boot.\n\n"
               "  -h --help                 Show this help\n"
               "     --max-file-size=BYTES  Maximum size of files to read ahead\n",
               program_invocation_short_name);

        return 0;
}

static int parse_argv(int argc, char *argv[]) {

        enum {
                ARG_FILE_SIZE_MAX
        };

        static const struct option options[] = {
                { "help",          no_argument,       NULL, 'h'                },
                { "file-size-max", required_argument, NULL, ARG_FILE_SIZE_MAX  },
                { NULL,            0,                 NULL, 0                  }
        };

        int c;

        assert(argc >= 0);
        assert(argv);

        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {

                switch (c) {

                case 'h':
                        help();
                        return 0;

                case ARG_FILE_SIZE_MAX: {
                        unsigned long long ull;

                        if (safe_atollu(optarg, &ull) < 0 || ull <= 0) {
                                log_error("Failed to parse maximum file size %s.", optarg);
                                return -EINVAL;
                        }

                        arg_file_size_max = (off_t) ull;
                        break;
                }

                case '?':
                        return -EINVAL;

                default:
                        log_error("Unknown option code %c", c);
                        return -EINVAL;
                }
        }

        if (optind != argc &&
            optind != argc-1) {
                help();
                return -EINVAL;
        }

        return 1;
}

int main(int argc, char*argv[]) {
        int r;
        const char *root;

        log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
        log_parse_environment();
        log_open();

        umask(0022);

        if ((r = parse_argv(argc, argv)) <= 0)
                return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;

        root = optind < argc ? argv[optind] : "/";

        if (!enough_ram()) {
                log_info("Disabling readahead replay due to low memory.");
                return 0;
        }

        if (detect_virtualization(NULL) > 0) {
                log_info("Disabling readahead replay due to execution in virtualized environment.");
                return 0;
        }

        if (!(shared = shared_get()))
                return 1;

        shared->replay = getpid();
        __sync_synchronize();

        if (replay(root) < 0)
                return 1;

        return 0;
}