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 < 0 || ts->tv_nsec < 0)
 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 < 0 || ts->tv_nsec < 0)
 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 < 0 || tv->tv_usec < 0)
 236                 return USEC_INFINITY;
 237
 238         if ((usec_t) tv->tv_sec > (UINT64_MAX - tv->tv_usec) / USEC_PER_SEC)
 239                 return USEC_INFINITY;
 240
 241         return
 242                 (usec_t) tv->tv_sec * USEC_PER_SEC +
 243                 (usec_t) tv->tv_usec;
 244 }
 245
 246 struct timeval *timeval_store(struct timeval *tv, usec_t u) {
 247         assert(tv);
 248
 249         if (u == USEC_INFINITY) {
 250                 tv->tv_sec = (time_t) -1;
 251                 tv->tv_usec = (suseconds_t) -1;
 252         } else {
 253                 tv->tv_sec = (time_t) (u / USEC_PER_SEC);
 254                 tv->tv_usec = (suseconds_t) (u % USEC_PER_SEC);
 255         }
 256
 257         return tv;
 258 }
 259
 260 static char *format_timestamp_internal(
 261                 char *buf,
 262                 size_t l,
 263                 usec_t t,
 264                 bool utc,
 265                 bool us) {
 266
 267         /* The weekdays in non-localized (English) form. We use this instead of the localized form, so that our
 268          * generated timestamps may be parsed with parse_timestamp(), and always read the same. */
 269         static const char * const weekdays[] = {
 270                 [0] = "Sun",
 271                 [1] = "Mon",
 272                 [2] = "Tue",
 273                 [3] = "Wed",
 274                 [4] = "Thu",
 275                 [5] = "Fri",
 276                 [6] = "Sat",
 277         };
 278
 279         struct tm tm;
 280         time_t sec;
 281         size_t n;
 282
 283         assert(buf);
 284
 285         if (l <
 286             3 +                  /* week day */
 287             1 + 10 +             /* space and date */
 288             1 + 8 +              /* space and time */
 289             (us ? 1 + 6 : 0) +   /* "." and microsecond part */
 290             1 + 1 +              /* space and shortest possible zone */
 291             1)
 292                 return NULL; /* Not enough space even for the shortest form. */
 293         if (t <= 0 || t == USEC_INFINITY)
 294                 return NULL; /* Timestamp is unset */
 295
 296         sec = (time_t) (t / USEC_PER_SEC); /* Round down */
 297         if ((usec_t) sec != (t / USEC_PER_SEC))
 298                 return NULL; /* overflow? */
 299
 300         if (!localtime_or_gmtime_r(&sec, &tm, utc))
 301                 return NULL;
 302
 303         /* Start with the week day */
 304         assert((size_t) tm.tm_wday < ELEMENTSOF(weekdays));
 305         memcpy(buf, weekdays[tm.tm_wday], 4);
 306
 307         /* Add the main components */
 308         if (strftime(buf + 3, l - 3, " %Y-%m-%d %H:%M:%S", &tm) <= 0)
 309                 return NULL; /* Doesn't fit */
 310
 311         /* Append the microseconds part, if that's requested */
 312         if (us) {
 313                 n = strlen(buf);
 314                 if (n + 8 > l)
 315                         return NULL; /* Microseconds part doesn't fit. */
 316
 317                 sprintf(buf + n, ".%06"PRI_USEC, t % USEC_PER_SEC);
 318         }
 319
 320         /* Append the timezone */
 321         n = strlen(buf);
 322         if (utc) {
 323                 /* If this is UTC then let's explicitly use the "UTC" string here, because gmtime_r() normally uses the
 324                  * obsolete "GMT" instead. */
 325                 if (n + 5 > l)
 326                         return NULL; /* "UTC" doesn't fit. */
 327
 328                 strcpy(buf + n, " UTC");
 329
 330         } else if (!isempty(tm.tm_zone)) {
 331                 size_t tn;
 332
 333                 /* An explicit timezone is specified, let's use it, if it fits */
 334                 tn = strlen(tm.tm_zone);
 335                 if (n + 1 + tn + 1 > l) {
 336                         /* The full time zone does not fit in. Yuck. */
 337
 338                         if (n + 1 + _POSIX_TZNAME_MAX + 1 > l)
 339                                 return NULL; /* Not even enough space for the POSIX minimum (of 6)? In that case, complain that it doesn't fit */
 340
 341                         /* So the time zone doesn't fit in fully, but the caller passed enough space for the POSIX
 342                          * minimum time zone length. In this case suppress the timezone entirely, in order not to dump
 343                          * an overly long, hard to read string on the user. This should be safe, because the user will
 344                          * assume the local timezone anyway if none is shown. And so does parse_timestamp(). */
 345                 } else {
 346                         buf[n++] = ' ';
 347                         strcpy(buf + n, tm.tm_zone);
 348                 }
 349         }
 350
 351         return buf;
 352 }
 353
 354 char *format_timestamp(char *buf, size_t l, usec_t t) {
 355         return format_timestamp_internal(buf, l, t, false, false);
 356 }
 357
 358 #if 0 /// UNNEEDED by elogind
 359 char *format_timestamp_utc(char *buf, size_t l, usec_t t) {
 360         return format_timestamp_internal(buf, l, t, true, false);
 361 }
 362 #endif // 0
 363
 364 char *format_timestamp_us(char *buf, size_t l, usec_t t) {
 365         return format_timestamp_internal(buf, l, t, false, true);
 366 }
 367
 368 #if 0 /// UNNEEDED by elogind
 369 char *format_timestamp_us_utc(char *buf, size_t l, usec_t t) {
 370         return format_timestamp_internal(buf, l, t, true, true);
 371 }
 372 #endif // 0
 373
 374 char *format_timestamp_relative(char *buf, size_t l, usec_t t) {
 375         const char *s;
 376         usec_t n, d;
 377
 378         if (t <= 0 || t == USEC_INFINITY)
 379                 return NULL;
 380
 381         n = now(CLOCK_REALTIME);
 382         if (n > t) {
 383                 d = n - t;
 384                 s = "ago";
 385         } else {
 386                 d = t - n;
 387                 s = "left";
 388         }
 389
 390         if (d >= USEC_PER_YEAR)
 391                 snprintf(buf, l, USEC_FMT " years " USEC_FMT " months %s",
 392                          d / USEC_PER_YEAR,
 393                          (d % USEC_PER_YEAR) / USEC_PER_MONTH, s);
 394         else if (d >= USEC_PER_MONTH)
 395                 snprintf(buf, l, USEC_FMT " months " USEC_FMT " days %s",
 396                          d / USEC_PER_MONTH,
 397                          (d % USEC_PER_MONTH) / USEC_PER_DAY, s);
 398         else if (d >= USEC_PER_WEEK)
 399                 snprintf(buf, l, USEC_FMT " weeks " USEC_FMT " days %s",
 400                          d / USEC_PER_WEEK,
 401                          (d % USEC_PER_WEEK) / USEC_PER_DAY, s);
 402         else if (d >= 2*USEC_PER_DAY)
 403                 snprintf(buf, l, USEC_FMT " days %s", d / USEC_PER_DAY, s);
 404         else if (d >= 25*USEC_PER_HOUR)
 405                 snprintf(buf, l, "1 day " USEC_FMT "h %s",
 406                          (d - USEC_PER_DAY) / USEC_PER_HOUR, s);
 407         else if (d >= 6*USEC_PER_HOUR)
 408                 snprintf(buf, l, USEC_FMT "h %s",
 409                          d / USEC_PER_HOUR, s);
 410         else if (d >= USEC_PER_HOUR)
 411                 snprintf(buf, l, USEC_FMT "h " USEC_FMT "min %s",
 412                          d / USEC_PER_HOUR,
 413                          (d % USEC_PER_HOUR) / USEC_PER_MINUTE, s);
 414         else if (d >= 5*USEC_PER_MINUTE)
 415                 snprintf(buf, l, USEC_FMT "min %s",
 416                          d / USEC_PER_MINUTE, s);
 417         else if (d >= USEC_PER_MINUTE)
 418                 snprintf(buf, l, USEC_FMT "min " USEC_FMT "s %s",
 419                          d / USEC_PER_MINUTE,
 420                          (d % USEC_PER_MINUTE) / USEC_PER_SEC, s);
 421         else if (d >= USEC_PER_SEC)
 422                 snprintf(buf, l, USEC_FMT "s %s",
 423                          d / USEC_PER_SEC, s);
 424         else if (d >= USEC_PER_MSEC)
 425                 snprintf(buf, l, USEC_FMT "ms %s",
 426                          d / USEC_PER_MSEC, s);
 427         else if (d > 0)
 428                 snprintf(buf, l, USEC_FMT"us %s",
 429                          d, s);
 430         else
 431                 snprintf(buf, l, "now");
 432
 433         buf[l-1] = 0;
 434         return buf;
 435 }
 436
 437 char *format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy) {
 438         static const struct {
 439                 const char *suffix;
 440                 usec_t usec;
 441         } table[] = {
 442                 { "y",     USEC_PER_YEAR   },
 443                 { "month", USEC_PER_MONTH  },
 444                 { "w",     USEC_PER_WEEK   },
 445                 { "d",     USEC_PER_DAY    },
 446                 { "h",     USEC_PER_HOUR   },
 447                 { "min",   USEC_PER_MINUTE },
 448                 { "s",     USEC_PER_SEC    },
 449                 { "ms",    USEC_PER_MSEC   },
 450                 { "us",    1               },
 451         };
 452
 453         unsigned i;
 454         char *p = buf;
 455         bool something = false;
 456
 457         assert(buf);
 458         assert(l > 0);
 459
 460         if (t == USEC_INFINITY) {
 461                 strncpy(p, "infinity", l-1);
 462                 p[l-1] = 0;
 463                 return p;
 464         }
 465
 466         if (t <= 0) {
 467                 strncpy(p, "0", l-1);
 468                 p[l-1] = 0;
 469                 return p;
 470         }
 471
 472         /* The result of this function can be parsed with parse_sec */
 473
 474         for (i = 0; i < ELEMENTSOF(table); i++) {
 475                 int k = 0;
 476                 size_t n;
 477                 bool done = false;
 478                 usec_t a, b;
 479
 480                 if (t <= 0)
 481                         break;
 482
 483                 if (t < accuracy && something)
 484                         break;
 485
 486                 if (t < table[i].usec)
 487                         continue;
 488
 489                 if (l <= 1)
 490                         break;
 491
 492                 a = t / table[i].usec;
 493                 b = t % table[i].usec;
 494
 495                 /* Let's see if we should shows this in dot notation */
 496                 if (t < USEC_PER_MINUTE && b > 0) {
 497                         usec_t cc;
 498                         int j;
 499
 500                         j = 0;
 501                         for (cc = table[i].usec; cc > 1; cc /= 10)
 502                                 j++;
 503
 504                         for (cc = accuracy; cc > 1; cc /= 10) {
 505                                 b /= 10;
 506                                 j--;
 507                         }
 508
 509                         if (j > 0) {
 510                                 k = snprintf(p, l,
 511                                              "%s"USEC_FMT".%0*"PRI_USEC"%s",
 512                                              p > buf ? " " : "",
 513                                              a,
 514                                              j,
 515                                              b,
 516                                              table[i].suffix);
 517
 518                                 t = 0;
 519                                 done = true;
 520                         }
 521                 }
 522
 523                 /* No? Then let's show it normally */
 524                 if (!done) {
 525                         k = snprintf(p, l,
 526                                      "%s"USEC_FMT"%s",
 527                                      p > buf ? " " : "",
 528                                      a,
 529                                      table[i].suffix);
 530
 531                         t = b;
 532                 }
 533
 534                 n = MIN((size_t) k, l);
 535
 536                 l -= n;
 537                 p += n;
 538
 539                 something = true;
 540         }
 541
 542         *p = 0;
 543
 544         return buf;
 545 }
 546
 547 #if 0 /// UNNEEDED by elogind
 548 void dual_timestamp_serialize(FILE *f, const char *name, dual_timestamp *t) {
 549
 550         assert(f);
 551         assert(name);
 552         assert(t);
 553
 554         if (!dual_timestamp_is_set(t))
 555                 return;
 556
 557         fprintf(f, "%s="USEC_FMT" "USEC_FMT"\n",
 558                 name,
 559                 t->realtime,
 560                 t->monotonic);
 561 }
 562
 563 int dual_timestamp_deserialize(const char *value, dual_timestamp *t) {
 564         unsigned long long a, b;
 565
 566         assert(value);
 567         assert(t);
 568
 569         if (sscanf(value, "%llu %llu", &a, &b) != 2) {
 570                 log_debug("Failed to parse dual timestamp value \"%s\": %m", value);
 571                 return -EINVAL;
 572         }
 573
 574         t->realtime = a;
 575         t->monotonic = b;
 576
 577         return 0;
 578 }
 579
 580 #endif // 0
 581 int timestamp_deserialize(const char *value, usec_t *timestamp) {
 582         int r;
 583
 584         assert(value);
 585
 586         r = safe_atou64(value, timestamp);
 587         if (r < 0)
 588                 return log_debug_errno(r, "Failed to parse timestamp value \"%s\": %m", value);
 589
 590         return r;
 591 }
 592
 593 #if 0 /// UNNEEDED by elogind
 594 int parse_timestamp(const char *t, usec_t *usec) {
 595         static const struct {
 596                 const char *name;
 597                 const int nr;
 598         } day_nr[] = {
 599                 { "Sunday",    0 },
 600                 { "Sun",       0 },
 601                 { "Monday",    1 },
 602                 { "Mon",       1 },
 603                 { "Tuesday",   2 },
 604                 { "Tue",       2 },
 605                 { "Wednesday", 3 },
 606                 { "Wed",       3 },
 607                 { "Thursday",  4 },
 608                 { "Thu",       4 },
 609                 { "Friday",    5 },
 610                 { "Fri",       5 },
 611                 { "Saturday",  6 },
 612                 { "Sat",       6 },
 613         };
 614
 615         const char *k, *utc, *tzn = NULL;
 616         struct tm tm, copy;
 617         time_t x;
 618         usec_t x_usec, plus = 0, minus = 0, ret;
 619         int r, weekday = -1, dst = -1;
 620         unsigned i;
 621
 622         /*
 623          * Allowed syntaxes:
 624          *
 625          *   2012-09-22 16:34:22
 626          *   2012-09-22 16:34     (seconds will be set to 0)
 627          *   2012-09-22           (time will be set to 00:00:00)
 628          *   16:34:22             (date will be set to today)
 629          *   16:34                (date will be set to today, seconds to 0)
 630          *   now
 631          *   yesterday            (time is set to 00:00:00)
 632          *   today                (time is set to 00:00:00)
 633          *   tomorrow             (time is set to 00:00:00)
 634          *   +5min
 635          *   -5days
 636          *   @2147483647          (seconds since epoch)
 637          *
 638          */
 639
 640         assert(t);
 641         assert(usec);
 642
 643         if (t[0] == '@')
 644                 return parse_sec(t + 1, usec);
 645
 646         ret = now(CLOCK_REALTIME);
 647
 648         if (streq(t, "now"))
 649                 goto finish;
 650
 651         else if (t[0] == '+') {
 652                 r = parse_sec(t+1, &plus);
 653                 if (r < 0)
 654                         return r;
 655
 656                 goto finish;
 657
 658         } else if (t[0] == '-') {
 659                 r = parse_sec(t+1, &minus);
 660                 if (r < 0)
 661                         return r;
 662
 663                 goto finish;
 664
 665         } else if ((k = endswith(t, " ago"))) {
 666                 t = strndupa(t, k - t);
 667
 668                 r = parse_sec(t, &minus);
 669                 if (r < 0)
 670                         return r;
 671
 672                 goto finish;
 673
 674         } else if ((k = endswith(t, " left"))) {
 675                 t = strndupa(t, k - t);
 676
 677                 r = parse_sec(t, &plus);
 678                 if (r < 0)
 679                         return r;
 680
 681                 goto finish;
 682         }
 683
 684         /* See if the timestamp is suffixed with UTC */
 685         utc = endswith_no_case(t, " UTC");
 686         if (utc)
 687                 t = strndupa(t, utc - t);
 688         else {
 689                 const char *e = NULL;
 690                 int j;
 691
 692                 tzset();
 693
 694                 /* See if the timestamp is suffixed by either the DST or non-DST local timezone. Note that we only
 695                  * support the local timezones here, nothing else. Not because we wouldn't want to, but simply because
 696                  * there are no nice APIs available to cover this. By accepting the local time zone strings, we make
 697                  * sure that all timestamps written by format_timestamp() can be parsed correctly, even though we don't
 698                  * support arbitrary timezone specifications.  */
 699
 700                 for (j = 0; j <= 1; j++) {
 701
 702                         if (isempty(tzname[j]))
 703                                 continue;
 704
 705                         e = endswith_no_case(t, tzname[j]);
 706                         if (!e)
 707                                 continue;
 708                         if (e == t)
 709                                 continue;
 710                         if (e[-1] != ' ')
 711                                 continue;
 712
 713                         break;
 714                 }
 715
 716                 if (IN_SET(j, 0, 1)) {
 717                         /* Found one of the two timezones specified. */
 718                         t = strndupa(t, e - t - 1);
 719                         dst = j;
 720                         tzn = tzname[j];
 721                 }
 722         }
 723
 724         x = (time_t) (ret / USEC_PER_SEC);
 725         x_usec = 0;
 726
 727         if (!localtime_or_gmtime_r(&x, &tm, utc))
 728                 return -EINVAL;
 729
 730         tm.tm_isdst = dst;
 731         if (tzn)
 732                 tm.tm_zone = tzn;
 733
 734         if (streq(t, "today")) {
 735                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 736                 goto from_tm;
 737
 738         } else if (streq(t, "yesterday")) {
 739                 tm.tm_mday--;
 740                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 741                 goto from_tm;
 742
 743         } else if (streq(t, "tomorrow")) {
 744                 tm.tm_mday++;
 745                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 746                 goto from_tm;
 747         }
 748
 749         for (i = 0; i < ELEMENTSOF(day_nr); i++) {
 750                 size_t skip;
 751
 752                 if (!startswith_no_case(t, day_nr[i].name))
 753                         continue;
 754
 755                 skip = strlen(day_nr[i].name);
 756                 if (t[skip] != ' ')
 757                         continue;
 758
 759                 weekday = day_nr[i].nr;
 760                 t += skip + 1;
 761                 break;
 762         }
 763
 764         copy = tm;
 765         k = strptime(t, "%y-%m-%d %H:%M:%S", &tm);
 766         if (k) {
 767                 if (*k == '.')
 768                         goto parse_usec;
 769                 else if (*k == 0)
 770                         goto from_tm;
 771         }
 772
 773         tm = copy;
 774         k = strptime(t, "%Y-%m-%d %H:%M:%S", &tm);
 775         if (k) {
 776                 if (*k == '.')
 777                         goto parse_usec;
 778                 else if (*k == 0)
 779                         goto from_tm;
 780         }
 781
 782         tm = copy;
 783         k = strptime(t, "%y-%m-%d %H:%M", &tm);
 784         if (k && *k == 0) {
 785                 tm.tm_sec = 0;
 786                 goto from_tm;
 787         }
 788
 789         tm = copy;
 790         k = strptime(t, "%Y-%m-%d %H:%M", &tm);
 791         if (k && *k == 0) {
 792                 tm.tm_sec = 0;
 793                 goto from_tm;
 794         }
 795
 796         tm = copy;
 797         k = strptime(t, "%y-%m-%d", &tm);
 798         if (k && *k == 0) {
 799                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 800                 goto from_tm;
 801         }
 802
 803         tm = copy;
 804         k = strptime(t, "%Y-%m-%d", &tm);
 805         if (k && *k == 0) {
 806                 tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
 807                 goto from_tm;
 808         }
 809
 810         tm = copy;
 811         k = strptime(t, "%H:%M:%S", &tm);
 812         if (k) {
 813                 if (*k == '.')
 814                         goto parse_usec;
 815                 else if (*k == 0)
 816                         goto from_tm;
 817         }
 818
 819         tm = copy;
 820         k = strptime(t, "%H:%M", &tm);
 821         if (k && *k == 0) {
 822                 tm.tm_sec = 0;
 823                 goto from_tm;
 824         }
 825
 826         return -EINVAL;
 827
 828 parse_usec:
 829         {
 830                 unsigned add;
 831
 832                 k++;
 833                 r = parse_fractional_part_u(&k, 6, &add);
 834                 if (r < 0)
 835                         return -EINVAL;
 836
 837                 if (*k)
 838                         return -EINVAL;
 839
 840                 x_usec = add;
 841         }
 842
 843 from_tm:
 844         x = mktime_or_timegm(&tm, utc);
 845         if (x < 0)
 846                 return -EINVAL;
 847
 848         if (weekday >= 0 && tm.tm_wday != weekday)
 849                 return -EINVAL;
 850
 851         ret = (usec_t) x * USEC_PER_SEC + x_usec;
 852
 853 finish:
 854         ret += plus;
 855         if (ret > minus)
 856                 ret -= minus;
 857         else
 858                 ret = 0;
 859
 860         *usec = ret;
 861
 862         return 0;
 863 }
 864 #endif // 0
 865
 866 static char* extract_multiplier(char *p, usec_t *multiplier) {
 867         static const struct {
 868                 const char *suffix;
 869                 usec_t usec;
 870         } table[] = {
 871                 { "seconds", USEC_PER_SEC    },
 872                 { "second",  USEC_PER_SEC    },
 873                 { "sec",     USEC_PER_SEC    },
 874                 { "s",       USEC_PER_SEC    },
 875                 { "minutes", USEC_PER_MINUTE },
 876                 { "minute",  USEC_PER_MINUTE },
 877                 { "min",     USEC_PER_MINUTE },
 878                 { "months",  USEC_PER_MONTH  },
 879                 { "month",   USEC_PER_MONTH  },
 880                 { "M",       USEC_PER_MONTH  },
 881                 { "msec",    USEC_PER_MSEC   },
 882                 { "ms",      USEC_PER_MSEC   },
 883                 { "m",       USEC_PER_MINUTE },
 884                 { "hours",   USEC_PER_HOUR   },
 885                 { "hour",    USEC_PER_HOUR   },
 886                 { "hr",      USEC_PER_HOUR   },
 887                 { "h",       USEC_PER_HOUR   },
 888                 { "days",    USEC_PER_DAY    },
 889                 { "day",     USEC_PER_DAY    },
 890                 { "d",       USEC_PER_DAY    },
 891                 { "weeks",   USEC_PER_WEEK   },
 892                 { "week",    USEC_PER_WEEK   },
 893                 { "w",       USEC_PER_WEEK   },
 894                 { "years",   USEC_PER_YEAR   },
 895                 { "year",    USEC_PER_YEAR   },
 896                 { "y",       USEC_PER_YEAR   },
 897                 { "usec",    1ULL            },
 898                 { "us",      1ULL            },
 899                 { "µs",      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                 { "µs", NSEC_PER_USEC },
1035                 { "nsec", 1ULL },
1036                 { "ns", 1ULL },
1037                 { "", 1ULL }, /* default is nsec */
1038         };
1039
1040         const char *p, *s;
1041         nsec_t r = 0;
1042         bool something = false;
1043
1044         assert(t);
1045         assert(nsec);
1046
1047         p = t;
1048
1049         p += strspn(p, WHITESPACE);
1050         s = startswith(p, "infinity");
1051         if (s) {
1052                 s += strspn(s, WHITESPACE);
1053                 if (*s != 0)
1054                         return -EINVAL;
1055
1056                 *nsec = NSEC_INFINITY;
1057                 return 0;
1058         }
1059
1060         for (;;) {
1061                 long long l, z = 0;
1062                 char *e;
1063                 unsigned i, n = 0;
1064
1065                 p += strspn(p, WHITESPACE);
1066
1067                 if (*p == 0) {
1068                         if (!something)
1069                                 return -EINVAL;
1070
1071                         break;
1072                 }
1073
1074                 errno = 0;
1075                 l = strtoll(p, &e, 10);
1076
1077                 if (errno > 0)
1078                         return -errno;
1079
1080                 if (l < 0)
1081                         return -ERANGE;
1082
1083                 if (*e == '.') {
1084                         char *b = e + 1;
1085
1086                         errno = 0;
1087                         z = strtoll(b, &e, 10);
1088                         if (errno > 0)
1089                                 return -errno;
1090
1091                         if (z < 0)
1092                                 return -ERANGE;
1093
1094                         if (e == b)
1095                                 return -EINVAL;
1096
1097                         n = e - b;
1098
1099                 } else if (e == p)
1100                         return -EINVAL;
1101
1102                 e += strspn(e, WHITESPACE);
1103
1104                 for (i = 0; i < ELEMENTSOF(table); i++)
1105                         if (startswith(e, table[i].suffix)) {
1106                                 nsec_t k = (nsec_t) z * table[i].nsec;
1107
1108                                 for (; n > 0; n--)
1109                                         k /= 10;
1110
1111                                 r += (nsec_t) l * table[i].nsec + k;
1112                                 p = e + strlen(table[i].suffix);
1113
1114                                 something = true;
1115                                 break;
1116                         }
1117
1118                 if (i >= ELEMENTSOF(table))
1119                         return -EINVAL;
1120
1121         }
1122
1123         *nsec = r;
1124
1125         return 0;
1126 }
1127
1128 bool ntp_synced(void) {
1129         struct timex txc = {};
1130
1131         if (adjtimex(&txc) < 0)
1132                 return false;
1133
1134         if (txc.status & STA_UNSYNC)
1135                 return false;
1136
1137         return true;
1138 }
1139
1140 int get_timezones(char ***ret) {
1141         _cleanup_fclose_ FILE *f = NULL;
1142         _cleanup_strv_free_ char **zones = NULL;
1143         size_t n_zones = 0, n_allocated = 0;
1144
1145         assert(ret);
1146
1147         zones = strv_new("UTC", NULL);
1148         if (!zones)
1149                 return -ENOMEM;
1150
1151         n_allocated = 2;
1152         n_zones = 1;
1153
1154         f = fopen("/usr/share/zoneinfo/zone.tab", "re");
1155         if (f) {
1156                 char l[LINE_MAX];
1157
1158                 FOREACH_LINE(l, f, return -errno) {
1159                         char *p, *w;
1160                         size_t k;
1161
1162                         p = strstrip(l);
1163
1164                         if (isempty(p) || *p == '#')
1165                                 continue;
1166
1167                         /* Skip over country code */
1168                         p += strcspn(p, WHITESPACE);
1169                         p += strspn(p, WHITESPACE);
1170
1171                         /* Skip over coordinates */
1172                         p += strcspn(p, WHITESPACE);
1173                         p += strspn(p, WHITESPACE);
1174
1175                         /* Found timezone name */
1176                         k = strcspn(p, WHITESPACE);
1177                         if (k <= 0)
1178                                 continue;
1179
1180                         w = strndup(p, k);
1181                         if (!w)
1182                                 return -ENOMEM;
1183
1184                         if (!GREEDY_REALLOC(zones, n_allocated, n_zones + 2)) {
1185                                 free(w);
1186                                 return -ENOMEM;
1187                         }
1188
1189                         zones[n_zones++] = w;
1190                         zones[n_zones] = NULL;
1191                 }
1192
1193                 strv_sort(zones);
1194
1195         } else if (errno != ENOENT)
1196                 return -errno;
1197
1198         *ret = zones;
1199         zones = NULL;
1200
1201         return 0;
1202 }
1203
1204 bool timezone_is_valid(const char *name) {
1205         bool slash = false;
1206         const char *p, *t;
1207         struct stat st;
1208
1209         if (isempty(name))
1210                 return false;
1211
1212         if (name[0] == '/')
1213                 return false;
1214
1215         for (p = name; *p; p++) {
1216                 if (!(*p >= '0' && *p <= '9') &&
1217                     !(*p >= 'a' && *p <= 'z') &&
1218                     !(*p >= 'A' && *p <= 'Z') &&
1219                     !(*p == '-' || *p == '_' || *p == '+' || *p == '/'))
1220                         return false;
1221
1222                 if (*p == '/') {
1223
1224                         if (slash)
1225                                 return false;
1226
1227                         slash = true;
1228                 } else
1229                         slash = false;
1230         }
1231
1232         if (slash)
1233                 return false;
1234
1235         t = strjoina("/usr/share/zoneinfo/", name);
1236         if (stat(t, &st) < 0)
1237                 return false;
1238
1239         if (!S_ISREG(st.st_mode))
1240                 return false;
1241
1242         return true;
1243 }
1244
1245 #endif // 0
1246 bool clock_boottime_supported(void) {
1247         static int supported = -1;
1248
1249         /* Note that this checks whether CLOCK_BOOTTIME is available in general as well as available for timerfds()! */
1250
1251         if (supported < 0) {
1252                 int fd;
1253
1254                 fd = timerfd_create(CLOCK_BOOTTIME, TFD_NONBLOCK|TFD_CLOEXEC);
1255                 if (fd < 0)
1256                         supported = false;
1257                 else {
1258                         safe_close(fd);
1259                         supported = true;
1260                 }
1261         }
1262
1263         return supported;
1264 }
1265
1266 #if 0 /// UNNEEDED by elogind
1267 clockid_t clock_boottime_or_monotonic(void) {
1268         if (clock_boottime_supported())
1269                 return CLOCK_BOOTTIME;
1270         else
1271                 return CLOCK_MONOTONIC;
1272 }
1273 #endif // 0
1274
1275 bool clock_supported(clockid_t clock) {
1276         struct timespec ts;
1277
1278         switch (clock) {
1279
1280         case CLOCK_MONOTONIC:
1281         case CLOCK_REALTIME:
1282                 return true;
1283
1284         case CLOCK_BOOTTIME:
1285                 return clock_boottime_supported();
1286
1287         case CLOCK_BOOTTIME_ALARM:
1288                 if (!clock_boottime_supported())
1289                         return false;
1290
1291                 /* fall through */
1292
1293         default:
1294                 /* For everything else, check properly */
1295                 return clock_gettime(clock, &ts) >= 0;
1296         }
1297 }
1298
1299 #if 0 /// UNNEEDED by elogind
1300 int get_timezone(char **tz) {
1301         _cleanup_free_ char *t = NULL;
1302         const char *e;
1303         char *z;
1304         int r;
1305
1306         r = readlink_malloc("/etc/localtime", &t);
1307         if (r < 0)
1308                 return r; /* returns EINVAL if not a symlink */
1309
1310         e = path_startswith(t, "/usr/share/zoneinfo/");
1311         if (!e)
1312                 e = path_startswith(t, "../usr/share/zoneinfo/");
1313         if (!e)
1314                 return -EINVAL;
1315
1316         if (!timezone_is_valid(e))
1317                 return -EINVAL;
1318
1319         z = strdup(e);
1320         if (!z)
1321                 return -ENOMEM;
1322
1323         *tz = z;
1324         return 0;
1325 }
1326
1327 time_t mktime_or_timegm(struct tm *tm, bool utc) {
1328         return utc ? timegm(tm) : mktime(tm);
1329 }
1330 #endif // 0
1331
1332 struct tm *localtime_or_gmtime_r(const time_t *t, struct tm *tm, bool utc) {
1333         return utc ? gmtime_r(t, tm) : localtime_r(t, tm);
1334 }
1335
1336 #if 0 /// UNNEEDED by elogind
1337 unsigned long usec_to_jiffies(usec_t u) {
1338         static thread_local unsigned long hz = 0;
1339         long r;
1340
1341         if (hz == 0) {
1342                 r = sysconf(_SC_CLK_TCK);
1343
1344                 assert(r > 0);
1345                 hz = r;
1346         }
1347
1348         return DIV_ROUND_UP(u , USEC_PER_SEC / hz);
1349 }
1350 #endif // 0