src/readahead/readahead-replay.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   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 <errno.h>
  23 #include <inttypes.h>
  24 #include <fcntl.h>
  25 #include <linux/limits.h>
  26 #include <stdbool.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <sys/select.h>
  31 #include <sys/time.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <unistd.h>
  35 #include <getopt.h>
  36 #include <sys/inotify.h>
  37
  38 #include "missing.h"
  39 #include "util.h"
  40 #include "set.h"
  41 #include "sd-daemon.h"
  42 #include "ioprio.h"
  43 #include "readahead-common.h"
  44 #include "virt.h"
  45
  46 static off_t arg_file_size_max = READAHEAD_FILE_SIZE_MAX;
  47
  48 static ReadaheadShared *shared = NULL;
  49
  50 static int unpack_file(FILE *pack) {
  51         char fn[PATH_MAX];
  52         int r = 0, fd = -1;
  53         bool any = false;
  54         struct stat st;
  55
  56         assert(pack);
  57
  58         if (!fgets(fn, sizeof(fn), pack))
  59                 return 0;
  60
  61         char_array_0(fn);
  62         truncate_nl(fn);
  63
  64         if ((fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW)) < 0) {
  65
  66                 if (errno != ENOENT && errno != EPERM && errno != EACCES)
  67                         log_warning("open(%s) failed: %m", fn);
  68
  69         } else if (file_verify(fd, fn, arg_file_size_max, &st) <= 0) {
  70                 close_nointr_nofail(fd);
  71                 fd = -1;
  72         }
  73
  74         for (;;) {
  75                 uint32_t b, c;
  76
  77                 if (fread(&b, sizeof(b), 1, pack) != 1 ||
  78                     fread(&c, sizeof(c), 1, pack) != 1) {
  79                         log_error("Premature end of pack file.");
  80                         r = -EIO;
  81                         goto finish;
  82                 }
  83
  84                 if (b == 0 && c == 0)
  85                         break;
  86
  87                 if (c <= b) {
  88                         log_error("Invalid pack file.");
  89                         r = -EIO;
  90                         goto finish;
  91                 }
  92
  93                 log_debug("%s: page %u to %u", fn, b, c);
  94
  95                 any = true;
  96
  97                 if (fd >= 0)
  98                         if (posix_fadvise(fd, b * page_size(), (c - b) * page_size(), POSIX_FADV_WILLNEED) < 0) {
  99                                 log_warning("posix_fadvise() failed: %m");
 100                                 goto finish;
 101                         }
 102         }
 103
 104         if (!any && fd >= 0) {
 105                 /* if no range is encoded in the pack file this is
 106                  * intended to mean that the whole file shall be
 107                  * read */
 108
 109                 if (posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED) < 0) {
 110                         log_warning("posix_fadvise() failed: %m");
 111                         goto finish;
 112                 }
 113         }
 114
 115 finish:
 116         if (fd >= 0)
 117                 close_nointr_nofail(fd);
 118
 119         return r;
 120 }
 121
 122 static int replay(const char *root) {
 123         FILE *pack = NULL;
 124         char line[LINE_MAX];
 125         int r = 0;
 126         char *pack_fn = NULL;
 127         int c;
 128         bool on_ssd, ready = false;
 129         int prio;
 130         int inotify_fd = -1;
 131
 132         assert(root);
 133
 134         write_one_line_file("/proc/self/oom_score_adj", "1000");
 135         bump_request_nr(root);
 136
 137         if (asprintf(&pack_fn, "%s/.readahead", root) < 0) {
 138                 log_error("Out of memory");
 139                 r = -ENOMEM;
 140                 goto finish;
 141         }
 142
 143         if ((!(pack = fopen(pack_fn, "re")))) {
 144                 if (errno == ENOENT)
 145                         log_debug("No pack file found.");
 146                 else {
 147                         log_error("Failed to open pack file: %m");
 148                         r = -errno;
 149                 }
 150
 151                 goto finish;
 152         }
 153
 154         posix_fadvise(fileno(pack), 0, 0, POSIX_FADV_WILLNEED);
 155
 156         if ((inotify_fd = open_inotify()) < 0) {
 157                 r = inotify_fd;
 158                 goto finish;
 159         }
 160
 161         if (!(fgets(line, sizeof(line), pack))) {
 162                 log_error("Premature end of pack file.");
 163                 r = -EIO;
 164                 goto finish;
 165         }
 166
 167         char_array_0(line);
 168
 169         if (!streq(line, CANONICAL_HOST "\n")) {
 170                 log_debug("Pack file host type mismatch.");
 171                 goto finish;
 172         }
 173
 174         if ((c = getc(pack)) == EOF) {
 175                 log_debug("Premature end of pack file.");
 176                 r = -EIO;
 177                 goto finish;
 178         }
 179
 180         /* We do not retest SSD here, so that we can start replaying
 181          * before udev is up.*/
 182         on_ssd = c == 'S';
 183         log_debug("On SSD: %s", yes_no(on_ssd));
 184
 185         if (on_ssd)
 186                 prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0);
 187         else
 188                 prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_RT, 7);
 189
 190         if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), prio) < 0)
 191                 log_warning("Failed to set IDLE IO priority class: %m");
 192
 193         sd_notify(0, "STATUS=Replaying readahead data");
 194
 195         log_debug("Replaying...");
 196
 197         if (access("/run/systemd/readahead/noreplay", F_OK) >= 0) {
 198                 log_debug("Got termination request");
 199                 goto done;
 200         }
 201
 202         while (!feof(pack) && !ferror(pack)) {
 203                 uint8_t inotify_buffer[sizeof(struct inotify_event) + FILENAME_MAX];
 204                 int k;
 205                 ssize_t n;
 206
 207                 if ((n = read(inotify_fd, &inotify_buffer, sizeof(inotify_buffer))) < 0) {
 208                         if (errno != EINTR && errno != EAGAIN) {
 209                                 log_error("Failed to read inotify event: %m");
 210                                 r = -errno;
 211                                 goto finish;
 212                         }
 213                 } else {
 214                         struct inotify_event *e = (struct inotify_event*) inotify_buffer;
 215
 216                         while (n > 0) {
 217                                 size_t step;
 218
 219                                 if ((e->mask & IN_CREATE) && streq(e->name, "noreplay")) {
 220                                         log_debug("Got termination request");
 221                                         goto done;
 222                                 }
 223
 224                                 step = sizeof(struct inotify_event) + e->len;
 225                                 assert(step <= (size_t) n);
 226
 227                                 e = (struct inotify_event*) ((uint8_t*) e + step);
 228                                 n -= step;
 229                         }
 230                 }
 231
 232                 if ((k = unpack_file(pack)) < 0) {
 233                         r = k;
 234                         goto finish;
 235                 }
 236
 237                 if (!ready) {
 238                         /* We delay the ready notification until we
 239                          * queued at least one read */
 240                         sd_notify(0, "READY=1");
 241                         ready = true;
 242                 }
 243         }
 244
 245 done:
 246         if (!ready)
 247                 sd_notify(0, "READY=1");
 248
 249         if (ferror(pack)) {
 250                 log_error("Failed to read pack file.");
 251                 r = -EIO;
 252                 goto finish;
 253         }
 254
 255         log_debug("Done.");
 256
 257 finish:
 258         if (pack)
 259                 fclose(pack);
 260
 261         if (inotify_fd >= 0)
 262                 close_nointr_nofail(inotify_fd);
 263
 264         free(pack_fn);
 265
 266         return r;
 267 }
 268
 269
 270 static int help(void) {
 271
 272         printf("%s [OPTIONS...] [DIRECTORY]\n\n"
 273                "Replay collected read-ahead data on early boot.\n\n"
 274                "  -h --help                 Show this help\n"
 275                "     --max-file-size=BYTES  Maximum size of files to read ahead\n",
 276                program_invocation_short_name);
 277
 278         return 0;
 279 }
 280
 281 static int parse_argv(int argc, char *argv[]) {
 282
 283         enum {
 284                 ARG_FILE_SIZE_MAX
 285         };
 286
 287         static const struct option options[] = {
 288                 { "help",          no_argument,       NULL, 'h'                },
 289                 { "file-size-max", required_argument, NULL, ARG_FILE_SIZE_MAX  },
 290                 { NULL,            0,                 NULL, 0                  }
 291         };
 292
 293         int c;
 294
 295         assert(argc >= 0);
 296         assert(argv);
 297
 298         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
 299
 300                 switch (c) {
 301
 302                 case 'h':
 303                         help();
 304                         return 0;
 305
 306                 case ARG_FILE_SIZE_MAX: {
 307                         unsigned long long ull;
 308
 309                         if (safe_atollu(optarg, &ull) < 0 || ull <= 0) {
 310                                 log_error("Failed to parse maximum file size %s.", optarg);
 311                                 return -EINVAL;
 312                         }
 313
 314                         arg_file_size_max = (off_t) ull;
 315                         break;
 316                 }
 317
 318                 case '?':
 319                         return -EINVAL;
 320
 321                 default:
 322                         log_error("Unknown option code %c", c);
 323                         return -EINVAL;
 324                 }
 325         }
 326
 327         if (optind != argc &&
 328             optind != argc-1) {
 329                 help();
 330                 return -EINVAL;
 331         }
 332
 333         return 1;
 334 }
 335
 336 int main(int argc, char*argv[]) {
 337         int r;
 338         const char *root;
 339
 340         log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
 341         log_parse_environment();
 342         log_open();
 343
 344         umask(0022);
 345
 346         if ((r = parse_argv(argc, argv)) <= 0)
 347                 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 348
 349         root = optind < argc ? argv[optind] : "/";
 350
 351         if (!enough_ram()) {
 352                 log_info("Disabling readahead replay due to low memory.");
 353                 return 0;
 354         }
 355
 356         if (detect_virtualization(NULL) > 0) {
 357                 log_info("Disabling readahead replay due to execution in virtualized environment.");
 358                 return 0;
 359         }
 360
 361         if (!(shared = shared_get()))
 362                 return 1;
 363
 364         shared->replay = getpid();
 365         __sync_synchronize();
 366
 367         if (replay(root) < 0)
 368                 return 1;
 369
 370         return 0;
 371 }