src/basic/time-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <limits.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/stat.h>
  25 #include <sys/time.h>
  26 #include <sys/timerfd.h>
  27 #include <sys/timex.h>
  28 #include <sys/types.h>
  29 #include <unistd.h>
  30
  31 #include "alloc-util.h"
  32 #include "fd-util.h"
  33 #include "fileio.h"
  34 #include "fs-util.h"
  35 #include "log.h"
  36 #include "macro.h"
  37 #include "parse-util.h"
  38 #include "path-util.h"
  39 #include "string-util.h"
  40 #include "strv.h"
  41 #include "time-util.h"
  42
  43 static clockid_t map_clock_id(clockid_t c) {
  44
  45         /* Some more exotic archs (s390, ppc, …) lack the "ALARM" flavour of the clocks. Thus, clock_gettime() will
  46          * fail for them. Since they are essentially the same as their non-ALARM pendants (their only difference is
  47          * when timers are set on them), let's just map them accordingly. This way, we can get the correct time even on
  48          * those archs. */
  49
  50         switch (c) {
  51
  52         case CLOCK_BOOTTIME_ALARM:
  53                 return CLOCK_BOOTTIME;
  54
  55         case CLOCK_REALTIME_ALARM:
  56                 return CLOCK_REALTIME;
  57
  58         default:
  59                 return c;
  60         }
  61 }
  62
  63 usec_t now(clockid_t clock_id) {
  64         struct timespec ts;
  65
  66         assert_se(clock_gettime(map_clock_id(clock_id), &ts) == 0);
  67
  68         return timespec_load(&ts);
  69 }
  70
  71 #if 0 /// UNNEEDED by elogind
  72 nsec_t now_nsec(clockid_t clock_id) {
  73         struct timespec ts;
  74
  75         assert_se(clock_gettime(map_clock_id(clock_id), &ts) == 0);
  76
  77         return timespec_load_nsec(&ts);
  78 }
  79 #endif // 0
  80
  81 dual_timestamp* dual_timestamp_get(dual_timestamp *ts) {
  82         assert(ts);
  83
  84         ts->realtime = now(CLOCK_REALTIME);
  85         ts->monotonic = now(CLOCK_MONOTONIC);
  86
  87         return ts;
  88 }
  89
  90 triple_timestamp* triple_timestamp_get(triple_timestamp *ts) {
  91         assert(ts);
  92
  93         ts->realtime = now(CLOCK_REALTIME);
  94         ts->monotonic = now(CLOCK_MONOTONIC);
  95         ts->boottime = clock_boottime_supported() ? now(CLOCK_BOOTTIME) : USEC_INFINITY;
  96
  97         return ts;
  98 }
  99
 100 dual_timestamp* dual_timestamp_from_realtime(dual_timestamp *ts, usec_t u) {
 101         int64_t delta;
 102         assert(ts);
 103
 104         if (u == USEC_INFINITY || u <= 0) {
 105                 ts->realtime = ts->monotonic = u;
 106                 return ts;
 107         }
 108
 109         ts->realtime = u;
 110
 111         delta = (int64_t) now(CLOCK_REALTIME) - (int64_t) u;
 112         ts->monotonic = usec_sub(now(CLOCK_MONOTONIC), delta);
 113
 114         return ts;
 115 }
 116
 117 #if 0 /// UNNEEDED by elogind
 118 triple_timestamp* triple_timestamp_from_realtime(triple_timestamp *ts, usec_t u) {
 119         int64_t delta;
 120
 121         assert(ts);
 122
 123         if (u == USEC_INFINITY || u <= 0) {
 124                 ts->realtime = ts->monotonic = ts->boottime = u;
 125                 return ts;
 126         }
 127
 128         ts->realtime = u;
 129         delta = (int64_t) now(CLOCK_REALTIME) - (int64_t) u;
 130         ts->monotonic = usec_sub(now(CLOCK_MONOTONIC), delta);
 131         ts->boottime = clock_boottime_supported() ? usec_sub(now(CLOCK_BOOTTIME), delta) : USEC_INFINITY;
 132
 133         return ts;
 134 }
 135
 136 dual_timestamp* dual_timestamp_from_monotonic(dual_timestamp *ts, usec_t u) {
 137         int64_t delta;
 138         assert(ts);
 139
 140         if (u == USEC_INFINITY) {
 141                 ts->realtime = ts->monotonic = USEC_INFINITY;
 142                 return ts;
 143         }
 144
 145         ts->monotonic = u;
 146         delta = (int64_t) now(CLOCK_MONOTONIC) - (int64_t) u;
 147         ts->realtime = usec_sub(now(CLOCK_REALTIME), delta);
 148
 149         return ts;
 150 }
 151
 152 dual_timestamp* dual_timestamp_from_boottime_or_monotonic(dual_timestamp *ts, usec_t u) {
 153         int64_t delta;
 154
 155         if (u == USEC_INFINITY) {
 156                 ts->realtime = ts->monotonic = USEC_INFINITY;
 157                 return ts;
 158         }
 159
 160         dual_timestamp_get(ts);
 161         delta = (int64_t) now(clock_boottime_or_monotonic()) - (int64_t) u;
 162         ts->realtime = usec_sub(ts->realtime, delta);
 163         ts->monotonic = usec_sub(ts->monotonic, delta);
 164
 165         return ts;
 166 }
 167 #endif // 0
 168
 169 usec_t triple_timestamp_by_clock(triple_timestamp *ts, clockid_t clock) {
 170
 171         switch (clock) {
 172
 173         case CLOCK_REALTIME:
 174         case CLOCK_REALTIME_ALARM:
 175                 return ts->realtime;
 176
 177         case CLOCK_MONOTONIC:
 178                 return ts->monotonic;
 179
 180         case CLOCK_BOOTTIME:
 181         case CLOCK_BOOTTIME_ALARM:
 182                 return ts->boottime;
 183
 184         default:
 185                 return USEC_INFINITY;
 186         }
 187 }
 188
 189 usec_t timespec_load(const struct timespec *ts) {
 190         assert(ts);
 191
 192         if (ts->tv_sec == (time_t) -1 && ts->tv_nsec == (long) -1)
 193                 return USEC_INFINITY;
 194
 195         if ((usec_t) ts->tv_sec > (UINT64_MAX - (ts->tv_nsec / NSEC_PER_USEC)) / USEC_PER_SEC)
 196                 return USEC_INFINITY;
 197
 198         return
 199                 (usec_t) ts->tv_sec * USEC_PER_SEC +
 200                 (usec_t) ts->tv_nsec / NSEC_PER_USEC;
 201 }
 202
 203 #if 0 /// UNNEEDED by elogind
 204 nsec_t timespec_load_nsec(const struct timespec *ts) {
 205         assert(ts);
 206
 207         if (ts->tv_sec == (time_t) -1 && ts->tv_nsec == (long) -1)
 208                 return NSEC_INFINITY;
 209
 210         if ((nsec_t) ts->tv_sec >= (UINT64_MAX - ts->tv_nsec) / NSEC_PER_SEC)
 211                 return NSEC_INFINITY;
 212
 213         return (nsec_t) ts->tv_sec * NSEC_PER_SEC + (nsec_t) ts->tv_nsec;
 214 }
 215 #endif // 0
 216
 217 struct timespec *timespec_store(struct timespec *ts, usec_t u)  {
 218         assert(ts);
 219
 220         if (u == USEC_INFINITY) {
 221                 ts->tv_sec = (time_t) -1;
 222                 ts->tv_nsec = (long) -1;
 223                 return ts;
 224         }
 225
 226         ts->tv_sec = (time_t) (u / USEC_PER_SEC);
 227         ts->tv_nsec = (long int) ((u % USEC_PER_SEC) * NSEC_PER_USEC);
 228
 229         return ts;
 230 }
 231
 232 usec_t timeval_load(const struct timeval *tv) {
 233         assert(tv);
 234
 235         if (tv->tv_sec == (time_t) -1 &&
 236             tv->tv_usec == (suseconds_t) -1)
 237                 return USEC_INFINITY;
 238
 239         if ((usec_t) tv->tv_sec > (UINT64_MAX - tv->tv_usec) / USEC_PER_SEC)
 240                 return USEC_INFINITY;
 241
 242         return
 243                 (usec_t) tv->tv_sec * USEC_PER_SEC +
 244                 (usec_t) tv->tv_usec;
 245 }
 246
 247 struct timeval *timeval_store(struct timeval *tv, usec_t u) {
 248         assert(tv);
 249
 250         if (u == USEC_INFINITY) {
 251                 tv->tv_sec = (time_t) -1;
 252                 tv->tv_usec = (suseconds_t) -1;
 253         } else {
 254                 tv->tv_sec = (time_t) (u / USEC_PER_SEC);
 255                 tv->tv_usec = (suseconds_t) (u % USEC_PER_SEC);
 256         }
 257
 258         return tv;
 259 }
 260
 261 static char *format_timestamp_internal(
 262                 char *buf,
 263                 size_t l,
 264                 usec_t t,
 265                 bool utc,
 266                 bool us) {
 267
 268         /* The weekdays in non-localized (English) form. We use this instead of the localized form, so that our
 269          * generated timestamps may be parsed with parse_timestamp(), and always read the same. */
 270         static const char * const weekdays[] = {
 271                 [0] = "Sun",
 272                 [1] = "Mon",
 273                 [2] = "Tue",
 274                 [3] = "Wed",
 275                 [4] = "Thu",
 276                 [5] = "Fri",
 277                 [6] = "Sat",
 278         };
 279
 280         struct tm tm;
 281         time_t sec;
 282         size_t n;
 283
 284         assert(buf);
 285
 286         if (l <
 287             3 +                  /* week day */
 288             1 + 10 +             /* space and date */
 289             1 + 8 +              /* space and time */
 290             (us ? 1 + 6 : 0) +   /* "." and microsecond part */
 291             1 + 1 +              /* space and shortest possible zone */
 292             1)
 293                 return NULL; /* Not enough space even for the shortest form. */
 294         if (t <= 0 || t == USEC_INFINITY)
 295                 return NULL; /* Timestamp is unset */
 296
 297         sec = (time_t) (t / USEC_PER_SEC); /* Round down */
 298         if ((usec_t) sec != (t / USEC_PER_SEC))
 299                 return NULL; /* overflow? */
 300
 301         if (!localtime_or_gmtime_r(&sec, &tm, utc))
 302                 return NULL;
 303
 304         /* Start with the week day */
 305         assert((size_t) tm.tm_wday < ELEMENTSOF(weekdays));
 306         memcpy(buf, weekdays[tm.tm_wday], 4);
 307
 308         /* Add the main components */
 309         if (strftime(buf + 3, l - 3, " %Y-%m-%d %H:%M:%S", &tm) <= 0)
 310                 return NULL; /* Doesn't fit */
 311
 312         /* Append the microseconds part, if that's requested */
 313         if (us) {
 314                 n = strlen(buf);
 315                 if (n + 8 > l)
 316                         return NULL; /* Microseconds part doesn't fit. */
 317
 318                 sprintf(buf + n, ".%06llu", (unsigned long long) (t % USEC_PER_SEC));
 319         }
 320
 321         /* Append the timezone */
 322         n = strlen(buf);
 323         if (utc) {
 324                 /* If this is UTC then let's explicitly use the "UTC" string here, because gmtime_r() normally uses the
 325                  * obsolete "GMT" instead. */
 326                 if (n + 5 > l)
 327                         return NULL; /* "UTC" doesn't fit. */
 328
 329                 strcpy(buf + n, " UTC");
 330
 331         } else if (!isempty(tm.tm_zone)) {
 332                 size_t tn;
 333
 334                 /* An explicit timezone is specified, let's use it, if it fits */
 335                 tn = strlen(tm.tm_zone);
 336                 if (n + 1 + tn + 1 > l) {
 337                         /* The full time zone does not fit in. Yuck. */
 338
 339                         if (n + 1 + _POSIX_TZNAME_MAX + 1 > l)
 340                                 return NULL; /* Not even enough space for the POSIX minimum (of 6)? In that case, complain that it doesn't fit */
 341
 342                         /* So the time zone doesn't fit in fully, but the caller passed enough space for the POSIX
 343                          * minimum time zone length. In this case suppress the timezone entirely, in order not to dump
 344                          * an overly long, hard to read string on the user. This should be safe, because the user will
 345                          * assume the local timezone anyway if none is shown. And so does parse_timestamp(). */
 346                 } else {
 347                         buf[n++] = ' ';
 348                         strcpy(buf + n, tm.tm_zone);
 349                 }
 350         }
 351
 352         return buf;
 353 }
 354
 355 char *format_timestamp(char *buf, size_t l, usec_t t) {
 356         return format_timestamp_internal(buf, l, t, false, false);
 357 }
 358
 359 #if 0 /// UNNEEDED by elogind
 360 char *format_timestamp_utc(char *buf, size_t l, usec_t t) {
 361         return format_timestamp_internal(buf, l, t, true, false);
 362 }
 363 #endif // 0
 364
 365 char *format_timestamp_us(char *buf, size_t l, usec_t t) {
 366         return format_timestamp_internal(buf, l, t, false, true);
 367 }
 368
 369 #if 0 /// UNNEEDED by elogind
 370 char *format_timestamp_us_utc(char *buf, size_t l, usec_t t) {
 371         return format_timestamp_internal(buf, l, t, true, true);
 372 }
 373 #endif // 0
 374
 375 char *format_timestamp_relative(char *buf, size_t l, usec_t t) {
 376         const char *s;
 377         usec_t n, d;
 378
 379         if (t <= 0 || t == USEC_INFINITY)
 380                 return NULL;
 381
 382         n = now(CLOCK_REALTIME);
 383         if (n > t) {
 384                 d = n - t;
 385                 s = "ago";
 386         } else {
 387                 d = t - n;
 388                 s = "left";
 389         }
 390
 391         if (d >= USEC_PER_YEAR)
 392                 snprintf(buf, l, USEC_FMT " years " USEC_FMT " months %s",
 393                          d / USEC_PER_YEAR,
 394                          (d % USEC_PER_YEAR) / USEC_PER_MONTH, s);
 395         else if (d >= USEC_PER_MONTH)
 396                 snprintf(buf, l, USEC_FMT " months " USEC_FMT " days %s",
 397                          d / USEC_PER_MONTH,
 398                          (d % USEC_PER_MONTH) / USEC_PER_DAY, s);
 399         else if (d >= USEC_PER_WEEK)
 400                 snprintf(buf, l, USEC_FMT " weeks " USEC_FMT " days %s",
 401                          d / USEC_PER_WEEK,
 402                          (d % USEC_PER_WEEK) / USEC_PER_DAY, s);
 403         else if (d >= 2*USEC_PER_DAY)
 404                 snprintf(buf, l, USEC_FMT " days %s", d / USEC_PER_DAY, s);
 405         else if (d >= 25*USEC_PER_HOUR)
 406                 snprintf(buf, l, "1 day " USEC_FMT "h %s",
 407                          (d - USEC_PER_DAY) / USEC_PER_HOUR, s);
 408         else if (d >= 6*USEC_PER_HOUR)
 409                 snprintf(buf, l, USEC_FMT "h %s",
 410                          d / USEC_PER_HOUR, s);
 411         else if (d >= USEC_PER_HOUR)
 412                 snprintf(buf, l, USEC_FMT "h " USEC_FMT "min %s",
 413                          d / USEC_PER_HOUR,
 414                          (d % USEC_PER_HOUR) / USEC_PER_MINUTE, s);
 415         else if (d >= 5*USEC_PER_MINUTE)
 416                 snprintf(buf, l, USEC_FMT "min %s",
 417                          d / USEC_PER_MINUTE, s);
 418         else if (d >= USEC_PER_MINUTE)
 419                 snprintf(buf, l, USEC_FMT "min " USEC_FMT "s %s",
 420                          d / USEC_PER_MINUTE,
 421                          (d % USEC_PER_MINUTE) / USEC_PER_SEC, s);
 422         else if (d >= USEC_PER_SEC)
 423                 snprintf(buf, l, USEC_FMT "s %s",
 424                          d / USEC_PER_SEC, s);
 425         else if (d >= USEC_PER_MSEC)
 426                 snprintf(buf, l, USEC_FMT "ms %s",
 427                          d / USEC_PER_MSEC, s);
 428         else if (d > 0)
 429                 snprintf(buf, l, USEC_FMT"us %s",
 430                          d, s);
 431         else
 432                 snprintf(buf, l, "now");
 433
 434         buf[l-1] = 0;
 435         return buf;
 436 }
 437
 438 char *format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy) {
 439         static const struct {
 440                 const char *suffix;
 441                 usec_t usec;
 442         } table[] = {
 443                 { "y",     USEC_PER_YEAR   },
 444                 { "month", USEC_PER_MONTH  },
 445                 { "w",     USEC_PER_WEEK   },
 446                 { "d",     USEC_PER_DAY    },
 447                 { "h",     USEC_PER_HOUR   },
 448                 { "min",   USEC_PER_MINUTE },
 449                 { "s",     USEC_PER_SEC    },
 450                 { "ms",    USEC_PER_MSEC   },
 451                 { "us",    1               },
 452         };
 453
 454         unsigned i;
 455         char *p = buf;
 456         bool something = false;
 457
 458         assert(buf);
 459         assert(l > 0);
 460
 461         if (t == USEC_INFINITY) {
 462                 strncpy(p, "infinity", l-1);
 463                 p[l-1] = 0;
 464                 return p;
 465         }
 466
 467         if (t <= 0) {
 468                 strncpy(p, "0", l-1);
 469                 p[l-1] = 0;
 470                 return p;
 471         }
 472
 473         /* The result of this function can be parsed with parse_sec */
 474
 475         for (i = 0; i < ELEMENTSOF(table); i++) {
 476                 int k = 0;
 477                 size_t n;
 478                 bool done = false;
 479                 usec_t a, b;
 480
 481                 if (t <= 0)
 482                         break;
 483
 484                 if (t < accuracy && something)
 485                         break;
 486
 487                 if (t < table[i].usec)
 488                         continue;
 489
 490                 if (l <= 1)
 491                         break;
 492
 493                 a = t / table[i].usec;
 494                 b = t % table[i].usec;
 495
 496                 /* Let's see if we should shows this in dot notation */
 497                 if (t < USEC_PER_MINUTE && b > 0) {
 498                         usec_t cc;
 499                         int j;
 500
 501                         j = 0;
 502                         for (cc = table[i].usec; cc > 1; cc /= 10)
 503                                 j++;
 504
 505                         for (cc = accuracy; cc > 1; cc /= 10) {
 506                                 b /= 10;
 507                                 j--;
 508                         }
 509
 510                         if (j > 0) {
 511                                 k = snprintf(p, l,
 512                                              "%s"USEC_FMT".%0*llu%s",
 513                                              p > buf ? " " : "",
 514                                              a,
 515                                              j,
 516                                              (unsigned long long) b,
 517                                              table[i].suffix);
 518
 519                                 t = 0;
 520                                 done = true;
 521                         }
 522                 }
 523
 524                 /* No? Then let's show it normally */
 525                 if (!done) {
 526                         k = snprintf(p, l,
 527                                      "%s"USEC_FMT"%s",
 528                                      p > buf ? " " : "",
 529                                      a,
 530                                      table[i].suffix);
 531
 532                         t = b;
 533                 }
 534
 535                 n = MIN((size_t) k, l);
 536
 537                 l -= n;
 538                 p += n;
 539
 540                 something = true;
 541         }
 542
 543         *p = 0;
 544
 545         return buf;
 546 }
 547
 548 #if 0 /// UNNEEDED by elogind
 549 void dual_timestamp_serialize(FILE *f, const char *name, dual_timestamp *t) {
 550
 551         assert(f);
 552         assert(name);
 553         assert(t);
 554
 555         if (!dual_timestamp_is_set(t))
 556                 return;
 557
 558         fprintf(f, "%s="USEC_FMT" "USEC_FMT"\n",
 559                 name,
 560                 t->realtime,
 561                 t->monotonic);
 562 }
 563
 564 int dual_timestamp_deserialize(const char *value, dual_timestamp *t) {
 565         unsigned long long a, b;
 566
 567         assert(value);
 568         assert(t);
 569
 570         if (sscanf(value, "%llu %llu", &a, &b) != 2) {
 571                 log_debug("Failed to parse dual timestamp value \"%s\": %m", value);
 572                 return -EINVAL;
 573         }
 574
 575         t->realtime = a;
 576         t->monotonic = b;
 577
 578         return 0;
 579 }
 580
 581 #endif // 0
 582 int timestamp_deserialize(const char *value, usec_t *timestamp) {
 583         int r;
 584
 585         assert(value);
 586
 587         r = safe_atou64(value, timestamp);
 588         if (r < 0)
 589                 return log_debug_errno(r, "Failed to parse timestamp value \"%s\": %m", value);
 590
 591         return r;
 592 }
 593
 594 #if 0 /// UNNEEDED by elogind
 595 int parse_timestamp(const char *t, usec_t *usec) {
 596         static const struct {
 597                 const char *name;
 598                 const int nr;
 599         } day_nr[] = {
 600                 { "Sunday",    0 },
 601                 { "Sun",       0 },
 602                 { "Monday",    1 },
 603                 { "Mon",       1 },
 604                 { "Tuesday",   2 },
 605                 { "Tue",       2 },
 606                 { "Wednesday", 3 },
 607                 { "Wed",       3 },
 608                 { "Thursday",  4 },
 609                 { "Thu",       4 },
 610                 { "Friday",    5 },
 611                 { "Fri",       5 },
 612                 { "Saturday",  6 },
 613                 { "Sat",       6 },
 614         };
 615
 616         const char *k, *utc, *tzn = NULL;
 617         struct tm tm, copy;
 618         time_t x;
 619         usec_t x_usec, plus = 0, minus = 0, ret;
 620         int r, weekday = -1, dst = -1;
 621         unsigned i;
 622
 623         /*
 624          * Allowed syntaxes:
 625          *
 626          *   2012-09-22 16:34:22
 627          *   2012-09-22 16:34     (seconds will be set to 0)
 628          *   2012-09-22           (time will be set to 00:00:00)
 629          *   16:34:22             (date will be set to today)
 630          *   16:34                (date will be set to today, seconds to 0)
 631          *   now
 632          *   yesterday            (time is set to 00:00:00)
 633          *   today                (time is set to 00:00:00)
 634          *   tomorrow             (time is set to 00:00:00)
 635          *   +5min
 636          *   -5days
 637          *   @2147483647          (seconds since epoch)
 638          *
 639          */
 640
 641         assert(t);
 642         assert(usec);
 643
 644         if (t[0] == '@')
 645                 return parse_sec(t + 1, usec);
 646
 647         ret = now(CLOCK_REALTIME);
 648
 649         if (streq(t, "now"))
 650                 goto finish;
 651
 652         else if (t[0] == '+') {
 653                 r = parse_sec(t+1, &plus);
 654                 if (r < 0)
 655                         return r;
 656
 657                 goto finish;
 658
 659         } else if (t[0] == '-') {
 660                 r = parse_sec(t+1, &minus);
 661                 if (r < 0)
 662                         return r;
 663
 664                 goto finish;
 665
 666         } else if ((k = endswith(t, " ago"))) {
 667                 t = strndupa(t, k - t);
 668
 669                 r = parse_sec(t, &minus);
 670                 if (r < 0)
 671                         return r;
 672
 673                 goto finish;
 674
 675         } else if ((k = endswith(t, " left"))) {
 676                 t = strndupa(t, k - t);
 677
 678                 r = parse_sec(t, &plus);
 679                 if (r < 0)
 680                         return r;
 681
 682                 goto finish;
 683         }
 684
 685         /* See if the timestamp is suffixed with UTC */
 686         utc = endswith_no_case(t, " UTC");
 687         if (utc)
 688                 t = strndupa(t, utc - t);
 689         else {
 690                 const char *e = NULL;
 691                 int j;
 692
 693                 tzset();
 694
 695                 /* See if the timestamp is suffixed by either the DST or non-DST local timezone. Note that we only
 696                  * support the local timezones here, nothing else. Not because we wouldn't want to, but simply because
 697                  * there are no nice APIs available to cover this. By accepting the local time zone strings, we make
 698                  * sure that all timestamps written by format_timestamp() can be parsed correctly, even though we don't
 699                  * support arbitrary timezone specifications.  */
 700
 701                 for (j = 0; j <= 1; j++) {
 702
 703                         if (isempty(tzname[j]))
 704                                 continue;
 705
 706                         e = endswith_no_case(t, tzname[j]);
 707                         if (!e)
 708                                 continue;
 709                         if (e == t)
 710                                 continue;
 711                         if (e[-1] != ' ')
 712                                 continue;
 713
 714                         break;
 715                 }
 716
 717                 if (IN_SET(j, 0, 1)) {
 718                         /* Found one of the two timezones specified. */
 719                         t = strndupa(t, e - t - 1);
 720                         dst = j;
 721                         tzn = tzname[j];
 722                 }
 723         }
 724
 725         x = (time_t) (ret / USEC_PER_SEC);
 726         x_usec = 0;
 727
 728         if (!localtime_or_gmtime_r(&x, &tm, utc))
 729                 return -EINVAL;
 730
 731         tm.tm_isdst = dst;
 732         if (tzn)
 733                 tm.tm_zone = tzn;
 734
 735         if (streq(t, "today")) {
 736                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 737                 goto from_tm;
 738
 739         } else if (streq(t, "yesterday")) {
 740                 tm.tm_mday--;
 741                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 742                 goto from_tm;
 743
 744         } else if (streq(t, "tomorrow")) {
 745                 tm.tm_mday++;
 746                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 747                 goto from_tm;
 748         }
 749
 750         for (i = 0; i < ELEMENTSOF(day_nr); i++) {
 751                 size_t skip;
 752
 753                 if (!startswith_no_case(t, day_nr[i].name))
 754                         continue;
 755
 756                 skip = strlen(day_nr[i].name);
 757                 if (t[skip] != ' ')
 758                         continue;
 759
 760                 weekday = day_nr[i].nr;
 761                 t += skip + 1;
 762                 break;
 763         }
 764
 765         copy = tm;
 766         k = strptime(t, "%y-%m-%d %H:%M:%S", &tm);
 767         if (k) {
 768                 if (*k == '.')
 769                         goto parse_usec;
 770                 else if (*k == 0)
 771                         goto from_tm;
 772         }
 773
 774         tm = copy;
 775         k = strptime(t, "%Y-%m-%d %H:%M:%S", &tm);
 776         if (k) {
 777                 if (*k == '.')
 778                         goto parse_usec;
 779                 else if (*k == 0)
 780                         goto from_tm;
 781         }
 782
 783         tm = copy;
 784         k = strptime(t, "%y-%m-%d %H:%M", &tm);
 785         if (k && *k == 0) {
 786                 tm.tm_sec = 0;
 787                 goto from_tm;
 788         }
 789
 790         tm = copy;
 791         k = strptime(t, "%Y-%m-%d %H:%M", &tm);
 792         if (k && *k == 0) {
 793                 tm.tm_sec = 0;
 794                 goto from_tm;
 795         }
 796
 797         tm = copy;
 798         k = strptime(t, "%y-%m-%d", &tm);
 799         if (k && *k == 0) {
 800                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 801                 goto from_tm;
 802         }
 803
 804         tm = copy;
 805         k = strptime(t, "%Y-%m-%d", &tm);
 806         if (k && *k == 0) {
 807                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 808                 goto from_tm;
 809         }
 810
 811         tm = copy;
 812         k = strptime(t, "%H:%M:%S", &tm);
 813         if (k) {
 814                 if (*k == '.')
 815                         goto parse_usec;
 816                 else if (*k == 0)
 817                         goto from_tm;
 818         }
 819
 820         tm = copy;
 821         k = strptime(t, "%H:%M", &tm);
 822         if (k && *k == 0) {
 823                 tm.tm_sec = 0;
 824                 goto from_tm;
 825         }
 826
 827         return -EINVAL;
 828
 829 parse_usec:
 830         {
 831                 unsigned add;
 832
 833                 k++;
 834                 r = parse_fractional_part_u(&k, 6, &add);
 835                 if (r < 0)
 836                         return -EINVAL;
 837
 838                 if (*k)
 839                         return -EINVAL;
 840
 841                 x_usec = add;
 842         }
 843
 844 from_tm:
 845         x = mktime_or_timegm(&tm, utc);
 846         if (x == (time_t) -1)
 847                 return -EINVAL;
 848
 849         if (weekday >= 0 && tm.tm_wday != weekday)
 850                 return -EINVAL;
 851
 852         ret = (usec_t) x * USEC_PER_SEC + x_usec;
 853
 854 finish:
 855         ret += plus;
 856         if (ret > minus)
 857                 ret -= minus;
 858         else
 859                 ret = 0;
 860
 861         *usec = ret;
 862
 863         return 0;
 864 }
 865 #endif // 0
 866
 867 static char* extract_multiplier(char *p, usec_t *multiplier) {
 868         static const struct {
 869                 const char *suffix;
 870                 usec_t usec;
 871         } table[] = {
 872                 { "seconds", USEC_PER_SEC    },
 873                 { "second",  USEC_PER_SEC    },
 874                 { "sec",     USEC_PER_SEC    },
 875                 { "s",       USEC_PER_SEC    },
 876                 { "minutes", USEC_PER_MINUTE },
 877                 { "minute",  USEC_PER_MINUTE },
 878                 { "min",     USEC_PER_MINUTE },
 879                 { "months",  USEC_PER_MONTH  },
 880                 { "month",   USEC_PER_MONTH  },
 881                 { "M",       USEC_PER_MONTH  },
 882                 { "msec",    USEC_PER_MSEC   },
 883                 { "ms",      USEC_PER_MSEC   },
 884                 { "m",       USEC_PER_MINUTE },
 885                 { "hours",   USEC_PER_HOUR   },
 886                 { "hour",    USEC_PER_HOUR   },
 887                 { "hr",      USEC_PER_HOUR   },
 888                 { "h",       USEC_PER_HOUR   },
 889                 { "days",    USEC_PER_DAY    },
 890                 { "day",     USEC_PER_DAY    },
 891                 { "d",       USEC_PER_DAY    },
 892                 { "weeks",   USEC_PER_WEEK   },
 893                 { "week",    USEC_PER_WEEK   },
 894                 { "w",       USEC_PER_WEEK   },
 895                 { "years",   USEC_PER_YEAR   },
 896                 { "year",    USEC_PER_YEAR   },
 897                 { "y",       USEC_PER_YEAR   },
 898                 { "usec",    1ULL            },
 899                 { "us",      1ULL            },
 900         };
 901         unsigned i;
 902
 903         for (i = 0; i < ELEMENTSOF(table); i++) {
 904                 char *e;
 905
 906                 e = startswith(p, table[i].suffix);
 907                 if (e) {
 908                         *multiplier = table[i].usec;
 909                         return e;
 910                 }
 911         }
 912
 913         return p;
 914 }
 915
 916 int parse_time(const char *t, usec_t *usec, usec_t default_unit) {
 917         const char *p, *s;
 918         usec_t r = 0;
 919         bool something = false;
 920
 921         assert(t);
 922         assert(usec);
 923         assert(default_unit > 0);
 924
 925         p = t;
 926
 927         p += strspn(p, WHITESPACE);
 928         s = startswith(p, "infinity");
 929         if (s) {
 930                 s += strspn(s, WHITESPACE);
 931                 if (*s != 0)
 932                         return -EINVAL;
 933
 934                 *usec = USEC_INFINITY;
 935                 return 0;
 936         }
 937
 938         for (;;) {
 939                 long long l, z = 0;
 940                 char *e;
 941                 unsigned n = 0;
 942                 usec_t multiplier = default_unit, k;
 943
 944                 p += strspn(p, WHITESPACE);
 945
 946                 if (*p == 0) {
 947                         if (!something)
 948                                 return -EINVAL;
 949
 950                         break;
 951                 }
 952
 953                 errno = 0;
 954                 l = strtoll(p, &e, 10);
 955                 if (errno > 0)
 956                         return -errno;
 957                 if (l < 0)
 958                         return -ERANGE;
 959
 960                 if (*e == '.') {
 961                         char *b = e + 1;
 962
 963                         errno = 0;
 964                         z = strtoll(b, &e, 10);
 965                         if (errno > 0)
 966                                 return -errno;
 967
 968                         if (z < 0)
 969                                 return -ERANGE;
 970
 971                         if (e == b)
 972                                 return -EINVAL;
 973
 974                         n = e - b;
 975
 976                 } else if (e == p)
 977                         return -EINVAL;
 978
 979                 e += strspn(e, WHITESPACE);
 980                 p = extract_multiplier(e, &multiplier);
 981
 982                 something = true;
 983
 984                 k = (usec_t) z * multiplier;
 985
 986                 for (; n > 0; n--)
 987                         k /= 10;
 988
 989                 r += (usec_t) l * multiplier + k;
 990         }
 991
 992         *usec = r;
 993
 994         return 0;
 995 }
 996
 997 int parse_sec(const char *t, usec_t *usec) {
 998         return parse_time(t, usec, USEC_PER_SEC);
 999 }
1000
1001 #if 0 /// UNNEEDED by elogind
1002 int parse_nsec(const char *t, nsec_t *nsec) {
1003         static const struct {
1004                 const char *suffix;
1005                 nsec_t nsec;
1006         } table[] = {
1007                 { "seconds", NSEC_PER_SEC },
1008                 { "second", NSEC_PER_SEC },
1009                 { "sec", NSEC_PER_SEC },
1010                 { "s", NSEC_PER_SEC },
1011                 { "minutes", NSEC_PER_MINUTE },
1012                 { "minute", NSEC_PER_MINUTE },
1013                 { "min", NSEC_PER_MINUTE },
1014                 { "months", NSEC_PER_MONTH },
1015                 { "month", NSEC_PER_MONTH },
1016                 { "msec", NSEC_PER_MSEC },
1017                 { "ms", NSEC_PER_MSEC },
1018                 { "m", NSEC_PER_MINUTE },
1019                 { "hours", NSEC_PER_HOUR },
1020                 { "hour", NSEC_PER_HOUR },
1021                 { "hr", NSEC_PER_HOUR },
1022                 { "h", NSEC_PER_HOUR },
1023                 { "days", NSEC_PER_DAY },
1024                 { "day", NSEC_PER_DAY },
1025                 { "d", NSEC_PER_DAY },
1026                 { "weeks", NSEC_PER_WEEK },
1027                 { "week", NSEC_PER_WEEK },
1028                 { "w", NSEC_PER_WEEK },
1029                 { "years", NSEC_PER_YEAR },
1030                 { "year", NSEC_PER_YEAR },
1031                 { "y", NSEC_PER_YEAR },
1032                 { "usec", NSEC_PER_USEC },
1033                 { "us", NSEC_PER_USEC },
1034                 { "nsec", 1ULL },
1035                 { "ns", 1ULL },
1036                 { "", 1ULL }, /* default is nsec */
1037         };
1038
1039         const char *p, *s;
1040         nsec_t r = 0;
1041         bool something = false;
1042
1043         assert(t);
1044         assert(nsec);
1045
1046         p = t;
1047
1048         p += strspn(p, WHITESPACE);
1049         s = startswith(p, "infinity");
1050         if (s) {
1051                 s += strspn(s, WHITESPACE);
1052                 if (*s != 0)
1053                         return -EINVAL;
1054
1055                 *nsec = NSEC_INFINITY;
1056                 return 0;
1057         }
1058
1059         for (;;) {
1060                 long long l, z = 0;
1061                 char *e;
1062                 unsigned i, n = 0;
1063
1064                 p += strspn(p, WHITESPACE);
1065
1066                 if (*p == 0) {
1067                         if (!something)
1068                                 return -EINVAL;
1069
1070                         break;
1071                 }
1072
1073                 errno = 0;
1074                 l = strtoll(p, &e, 10);
1075
1076                 if (errno > 0)
1077                         return -errno;
1078
1079                 if (l < 0)
1080                         return -ERANGE;
1081
1082                 if (*e == '.') {
1083                         char *b = e + 1;
1084
1085                         errno = 0;
1086                         z = strtoll(b, &e, 10);
1087                         if (errno > 0)
1088                                 return -errno;
1089
1090                         if (z < 0)
1091                                 return -ERANGE;
1092
1093                         if (e == b)
1094                                 return -EINVAL;
1095
1096                         n = e - b;
1097
1098                 } else if (e == p)
1099                         return -EINVAL;
1100
1101                 e += strspn(e, WHITESPACE);
1102
1103                 for (i = 0; i < ELEMENTSOF(table); i++)
1104                         if (startswith(e, table[i].suffix)) {
1105                                 nsec_t k = (nsec_t) z * table[i].nsec;
1106
1107                                 for (; n > 0; n--)
1108                                         k /= 10;
1109
1110                                 r += (nsec_t) l * table[i].nsec + k;
1111                                 p = e + strlen(table[i].suffix);
1112
1113                                 something = true;
1114                                 break;
1115                         }
1116
1117                 if (i >= ELEMENTSOF(table))
1118                         return -EINVAL;
1119
1120         }
1121
1122         *nsec = r;
1123
1124         return 0;
1125 }
1126
1127 bool ntp_synced(void) {
1128         struct timex txc = {};
1129
1130         if (adjtimex(&txc) < 0)
1131                 return false;
1132
1133         if (txc.status & STA_UNSYNC)
1134                 return false;
1135
1136         return true;
1137 }
1138
1139 int get_timezones(char ***ret) {
1140         _cleanup_fclose_ FILE *f = NULL;
1141         _cleanup_strv_free_ char **zones = NULL;
1142         size_t n_zones = 0, n_allocated = 0;
1143
1144         assert(ret);
1145
1146         zones = strv_new("UTC", NULL);
1147         if (!zones)
1148                 return -ENOMEM;
1149
1150         n_allocated = 2;
1151         n_zones = 1;
1152
1153         f = fopen("/usr/share/zoneinfo/zone.tab", "re");
1154         if (f) {
1155                 char l[LINE_MAX];
1156
1157                 FOREACH_LINE(l, f, return -errno) {
1158                         char *p, *w;
1159                         size_t k;
1160
1161                         p = strstrip(l);
1162
1163                         if (isempty(p) || *p == '#')
1164                                 continue;
1165
1166                         /* Skip over country code */
1167                         p += strcspn(p, WHITESPACE);
1168                         p += strspn(p, WHITESPACE);
1169
1170                         /* Skip over coordinates */
1171                         p += strcspn(p, WHITESPACE);
1172                         p += strspn(p, WHITESPACE);
1173
1174                         /* Found timezone name */
1175                         k = strcspn(p, WHITESPACE);
1176                         if (k <= 0)
1177                                 continue;
1178
1179                         w = strndup(p, k);
1180                         if (!w)
1181                                 return -ENOMEM;
1182
1183                         if (!GREEDY_REALLOC(zones, n_allocated, n_zones + 2)) {
1184                                 free(w);
1185                                 return -ENOMEM;
1186                         }
1187
1188                         zones[n_zones++] = w;
1189                         zones[n_zones] = NULL;
1190                 }
1191
1192                 strv_sort(zones);
1193
1194         } else if (errno != ENOENT)
1195                 return -errno;
1196
1197         *ret = zones;
1198         zones = NULL;
1199
1200         return 0;
1201 }
1202
1203 bool timezone_is_valid(const char *name) {
1204         bool slash = false;
1205         const char *p, *t;
1206         struct stat st;
1207
1208         if (isempty(name))
1209                 return false;
1210
1211         if (name[0] == '/')
1212                 return false;
1213
1214         for (p = name; *p; p++) {
1215                 if (!(*p >= '0' && *p <= '9') &&
1216                     !(*p >= 'a' && *p <= 'z') &&
1217                     !(*p >= 'A' && *p <= 'Z') &&
1218                     !(*p == '-' || *p == '_' || *p == '+' || *p == '/'))
1219                         return false;
1220
1221                 if (*p == '/') {
1222
1223                         if (slash)
1224                                 return false;
1225
1226                         slash = true;
1227                 } else
1228                         slash = false;
1229         }
1230
1231         if (slash)
1232                 return false;
1233
1234         t = strjoina("/usr/share/zoneinfo/", name);
1235         if (stat(t, &st) < 0)
1236                 return false;
1237
1238         if (!S_ISREG(st.st_mode))
1239                 return false;
1240
1241         return true;
1242 }
1243
1244 #endif // 0
1245 bool clock_boottime_supported(void) {
1246         static int supported = -1;
1247
1248         /* Note that this checks whether CLOCK_BOOTTIME is available in general as well as available for timerfds()! */
1249
1250         if (supported < 0) {
1251                 int fd;
1252
1253                 fd = timerfd_create(CLOCK_BOOTTIME, TFD_NONBLOCK|TFD_CLOEXEC);
1254                 if (fd < 0)
1255                         supported = false;
1256                 else {
1257                         safe_close(fd);
1258                         supported = true;
1259                 }
1260         }
1261
1262         return supported;
1263 }
1264
1265 #if 0 /// UNNEEDED by elogind
1266 clockid_t clock_boottime_or_monotonic(void) {
1267         if (clock_boottime_supported())
1268                 return CLOCK_BOOTTIME;
1269         else
1270                 return CLOCK_MONOTONIC;
1271 }
1272 #endif // 0
1273
1274 bool clock_supported(clockid_t clock) {
1275         struct timespec ts;
1276
1277         switch (clock) {
1278
1279         case CLOCK_MONOTONIC:
1280         case CLOCK_REALTIME:
1281                 return true;
1282
1283         case CLOCK_BOOTTIME:
1284                 return clock_boottime_supported();
1285
1286         case CLOCK_BOOTTIME_ALARM:
1287                 if (!clock_boottime_supported())
1288                         return false;
1289
1290                 /* fall through, after checking the cached value for CLOCK_BOOTTIME. */
1291
1292         default:
1293                 /* For everything else, check properly */
1294                 return clock_gettime(clock, &ts) >= 0;
1295         }
1296 }
1297
1298 #if 0 /// UNNEEDED by elogind
1299 int get_timezone(char **tz) {
1300         _cleanup_free_ char *t = NULL;
1301         const char *e;
1302         char *z;
1303         int r;
1304
1305         r = readlink_malloc("/etc/localtime", &t);
1306         if (r < 0)
1307                 return r; /* returns EINVAL if not a symlink */
1308
1309         e = path_startswith(t, "/usr/share/zoneinfo/");
1310         if (!e)
1311                 e = path_startswith(t, "../usr/share/zoneinfo/");
1312         if (!e)
1313                 return -EINVAL;
1314
1315         if (!timezone_is_valid(e))
1316                 return -EINVAL;
1317
1318         z = strdup(e);
1319         if (!z)
1320                 return -ENOMEM;
1321
1322         *tz = z;
1323         return 0;
1324 }
1325
1326 time_t mktime_or_timegm(struct tm *tm, bool utc) {
1327         return utc ? timegm(tm) : mktime(tm);
1328 }
1329 #endif // 0
1330
1331 struct tm *localtime_or_gmtime_r(const time_t *t, struct tm *tm, bool utc) {
1332         return utc ? gmtime_r(t, tm) : localtime_r(t, tm);
1333 }
1334
1335 #if 0 /// UNNEEDED by elogind
1336 unsigned long usec_to_jiffies(usec_t u) {
1337         static thread_local unsigned long hz = 0;
1338         long r;
1339
1340         if (hz == 0) {
1341                 r = sysconf(_SC_CLK_TCK);
1342
1343                 assert(r > 0);
1344                 hz = (unsigned long) r;
1345         }
1346
1347         return DIV_ROUND_UP(u , USEC_PER_SEC / hz);
1348 }
1349 #endif // 0