coreutils/date.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini date implementation for busybox
   4  *
   5  * by Matthew Grant <grantma@anathoth.gen.nz>
   6  *
   7  * iso-format handling added by Robert Griebl <griebl@gmx.de>
   8  * bugfixes and cleanup by Bernhard Reutner-Fischer
   9  *
  10  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  11  */
  12 /* This 'date' command supports only 2 time setting formats,
  13    all the GNU strftime stuff (its in libc, lets use it),
  14    setting time using UTC and displaying it, as well as
  15    an RFC 2822 compliant date output for shell scripting
  16    mail commands */
  17
  18 /* Input parsing code is always bulky - used heavy duty libc stuff as
  19    much as possible, missed out a lot of bounds checking */
  20
  21 //config:config DATE
  22 //config:       bool "date (7.2 kb)"
  23 //config:       default y
  24 //config:       help
  25 //config:       date is used to set the system date or display the
  26 //config:       current time in the given format.
  27 //config:
  28 //config:config FEATURE_DATE_ISOFMT
  29 //config:       bool "Enable ISO date format output (-I)"
  30 //config:       default y
  31 //config:       depends on DATE
  32 //config:       help
  33 //config:       Enable option (-I) to output an ISO-8601 compliant
  34 //config:       date/time string.
  35 //config:
  36 //config:config FEATURE_DATE_NANO
  37 //config:       bool "Support %[num]N nanosecond format specifier"
  38 //config:       default n # stat's nanosecond field is a bit non-portable
  39 //config:       depends on DATE
  40 //config:       help
  41 //config:       Support %[num]N format specifier. Adds ~250 bytes of code.
  42 //config:
  43 //config:config FEATURE_DATE_COMPAT
  44 //config:       bool "Support weird 'date MMDDhhmm[[YY]YY][.ss]' format"
  45 //config:       default y
  46 //config:       depends on DATE
  47 //config:       help
  48 //config:       System time can be set by 'date -s DATE' and simply 'date DATE',
  49 //config:       but formats of DATE string are different. 'date DATE' accepts
  50 //config:       a rather weird MMDDhhmm[[YY]YY][.ss] format with completely
  51 //config:       unnatural placement of year between minutes and seconds.
  52 //config:       date -s (and other commands like touch -d) use more sensible
  53 //config:       formats (for one, ISO format YYYY-MM-DD hh:mm:ss.ssssss).
  54 //config:
  55 //config:       With this option off, 'date DATE' and 'date -s DATE' support
  56 //config:       the same format. With it on, 'date DATE' additionally supports
  57 //config:       MMDDhhmm[[YY]YY][.ss] format.
  58
  59 //applet:IF_DATE(APPLET_NOEXEC(date, date, BB_DIR_BIN, BB_SUID_DROP, date))
  60 /* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
  61
  62 //kbuild:lib-$(CONFIG_DATE) += date.o
  63
  64 /* GNU coreutils 6.9 man page:
  65  * date [OPTION]... [+FORMAT]
  66  * date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]
  67  * -d, --date=STRING
  68  *      display time described by STRING, not 'now'
  69  * -f, --file=DATEFILE
  70  *      like --date once for each line of DATEFILE
  71  * -r, --reference=FILE
  72  *      display the last modification time of FILE
  73  * -R, --rfc-2822
  74  *      output date and time in RFC 2822 format.
  75  *      Example: Mon, 07 Aug 2006 12:34:56 -0600
  76  * --rfc-3339=TIMESPEC
  77  *      output date and time in RFC 3339 format.
  78  *      TIMESPEC='date', 'seconds', or 'ns'
  79  *      Date and time components are separated by a single space:
  80  *      2006-08-07 12:34:56-06:00
  81  * -s, --set=STRING
  82  *      set time described by STRING
  83  * -u, --utc, --universal
  84  *      print or set Coordinated Universal Time
  85  *
  86  * Busybox:
  87  * long options are not supported
  88  * -f is not supported
  89  * -I seems to roughly match --rfc-3339, but -I has _optional_ param
  90  *    (thus "-I seconds" doesn't work, only "-Iseconds"),
  91  *    and does not support -Ins
  92  * -D FMT is a bbox extension for _input_ conversion of -d DATE
  93  */
  94
  95 //usage:#define date_trivial_usage
  96 //usage:       "[OPTIONS] [+FMT] [[-s] TIME]"
  97 //usage:#define date_full_usage "\n\n"
  98 //usage:       "Display time (using +FMT), or set time\n"
  99 //usage:     "\n        -u              Work in UTC (don't convert to local time)"
 100 //usage:     "\n        [-s] TIME       Set time to TIME"
 101 //usage:     "\n        -d TIME         Display TIME, not 'now'"
 102 //usage:        IF_FEATURE_DATE_ISOFMT(
 103 //usage:     "\n        -D FMT          FMT (strptime format) for -s/-d TIME conversion"
 104 ////////^^^^^^^^^^^^^^^^^^^^^^ busybox invention, not compat
 105 //usage:        )
 106 //usage:     "\n        -r FILE         Display last modification time of FILE"
 107 //usage:     "\n        -R              Output RFC-2822 date"
 108 //usage:        IF_FEATURE_DATE_ISOFMT(
 109 //usage:     "\n        -I[SPEC]        Output ISO-8601 date"
 110 //usage:     "\n                        SPEC=date (default), hours, minutes, seconds or ns"
 111 //usage:        )
 112 //usage:     "\n"
 113 //usage:     "\nRecognized TIME formats:"
 114 //usage:     "\n        @seconds_since_1970"
 115 //usage:     "\n        hh:mm[:ss]"
 116 //usage:     "\n        [YYYY.]MM.DD-hh:mm[:ss]"
 117 //usage:     "\n        YYYY-MM-DD hh:mm[:ss]"
 118 //usage:     "\n        [[[[[YY]YY]MM]DD]hh]mm[.ss]"
 119 //usage:        IF_FEATURE_DATE_COMPAT(
 120 //usage:     "\n        'date TIME' form accepts MMDDhhmm[[YY]YY][.ss] instead"
 121 //usage:        )
 122 //usage:
 123 //usage:#define date_example_usage
 124 //usage:       "$ date\n"
 125 //usage:       "Wed Apr 12 18:52:41 MDT 2000\n"
 126
 127 #include "libbb.h"
 128 #include "common_bufsiz.h"
 129 #if ENABLE_FEATURE_DATE_NANO
 130 # include <sys/syscall.h>
 131 #endif
 132
 133 enum {
 134         OPT_RFC2822   = (1 << 0), /* R */
 135         OPT_SET       = (1 << 1), /* s */
 136         OPT_UTC       = (1 << 2), /* u */
 137         OPT_DATE      = (1 << 3), /* d */
 138         OPT_REFERENCE = (1 << 4), /* r */
 139         OPT_ISO8601   = (1 << 5) * ENABLE_FEATURE_DATE_ISOFMT, /* I */
 140         OPT_STR2DT    = (1 << 6) * ENABLE_FEATURE_DATE_ISOFMT, /* D */
 141 };
 142
 143 #if ENABLE_LONG_OPTS
 144 static const char date_longopts[] ALIGN1 =
 145                 "rfc-822\0"   No_argument       "R"
 146                 "rfc-2822\0"  No_argument       "R"
 147                 "set\0"       Required_argument "s"
 148                 "utc\0"       No_argument       "u"
 149         /*      "universal\0" No_argument       "u" */
 150                 "date\0"      Required_argument "d"
 151                 "reference\0" Required_argument "r"
 152                 ;
 153 #endif
 154
 155 /* We are a NOEXEC applet.
 156  * Obstacles to NOFORK:
 157  * - we change env
 158  * - xasprintf result not freed
 159  * - after xasprintf we use other xfuncs
 160  */
 161
 162 int date_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 163 int date_main(int argc UNUSED_PARAM, char **argv)
 164 {
 165         struct timespec ts;
 166         struct tm tm_time;
 167         char buf_fmt_dt2str[64];
 168         unsigned opt;
 169         int isofmt = -1;
 170         char *date_str;
 171         char *fmt_dt2str;
 172         char *fmt_str2dt;
 173         char *filename;
 174         char *isofmt_arg = NULL;
 175
 176         opt = getopt32long(argv, "^"
 177                         "Rs:ud:r:"
 178                         IF_FEATURE_DATE_ISOFMT("I::D:")
 179                         "\0"
 180                         "d--s:s--d"
 181                         IF_FEATURE_DATE_ISOFMT(":R--I:I--R"),
 182                         date_longopts,
 183                         &date_str, &date_str, &filename
 184                         IF_FEATURE_DATE_ISOFMT(, &isofmt_arg, &fmt_str2dt)
 185         );
 186         argv += optind;
 187
 188         if (opt & OPT_UTC)
 189                 putenv((char*)"TZ=UTC0");
 190
 191         if (ENABLE_FEATURE_DATE_ISOFMT && (opt & OPT_ISO8601)) {
 192                 isofmt = 0; /* default is date */
 193                 if (isofmt_arg) {
 194                         static const char isoformats[] ALIGN1 =
 195                                 "date\0""hours\0""minutes\0""seconds\0ns\0";
 196                         isofmt = index_in_substrings(isoformats, isofmt_arg);
 197                         if (isofmt < 0)
 198                                 bb_show_usage();
 199                 }
 200         }
 201
 202         fmt_dt2str = NULL;
 203         if (argv[0] && argv[0][0] == '+') {
 204                 fmt_dt2str = &argv[0][1]; /* skip over the '+' */
 205                 argv++;
 206         }
 207         if (!(opt & (OPT_SET | OPT_DATE))) { /* neither -s TIME nor -d TIME? */
 208                 opt |= OPT_SET;
 209                 date_str = argv[0]; /* can be NULL */
 210                 if (date_str) {
 211 #if ENABLE_FEATURE_DATE_COMPAT
 212                         int len = strspn(date_str, "0123456789");
 213                         if (date_str[len] == '\0'
 214                          || (date_str[len] == '.'
 215                             && isdigit(date_str[len+1])
 216                             && isdigit(date_str[len+2])
 217                             && date_str[len+3] == '\0'
 218                             )
 219                         ) {
 220                                 /* Dreaded MMDDhhmm[[CC]YY][.ss] format!
 221                                  * It does not match -d or -s format.
 222                                  * Some users actually do use it.
 223                                  */
 224                                 len -= 8;
 225                                 if (len < 0 || len > 4 || (len & 1))
 226                                         bb_error_msg_and_die(bb_msg_invalid_date, date_str);
 227                                 if (len != 0) { /* move YY or CCYY to front */
 228                                         char buf[4];
 229                                         memcpy(buf, date_str + 8, len);
 230                                         memmove(date_str + len, date_str, 8);
 231                                         memcpy(date_str, buf, len);
 232                                 }
 233                         }
 234 #endif
 235                         argv++;
 236                 }
 237         }
 238         if (*argv)
 239                 bb_show_usage();
 240
 241         /* Now we have parsed all the information except the date format
 242          * which depends on whether the clock is being set or read */
 243
 244         if (opt & OPT_REFERENCE) {
 245                 struct stat statbuf;
 246                 xstat(filename, &statbuf);
 247                 ts.tv_sec = statbuf.st_mtime;
 248 #if ENABLE_FEATURE_DATE_NANO
 249                 ts.tv_nsec = statbuf.st_mtim.tv_nsec;
 250                 /* Some toolchains use .st_mtimensec instead of st_mtim.tv_nsec.
 251                  * If you need #define _SVID_SOURCE 1 to enable st_mtim.tv_nsec,
 252                  * drop a mail to project mailing list please
 253                  */
 254 #endif
 255         } else {
 256 #if ENABLE_FEATURE_DATE_NANO
 257                 clock_gettime(CLOCK_REALTIME, &ts);
 258 #else
 259                 time(&ts.tv_sec);
 260 #endif
 261         }
 262 #if !ENABLE_FEATURE_DATE_NANO
 263         ts.tv_nsec = 0;
 264 #endif
 265         localtime_r(&ts.tv_sec, &tm_time);
 266
 267         /* If date string is given, update tm_time, and maybe set date */
 268         if (date_str != NULL) {
 269                 int check_dst = 1;
 270                 /* Zero out fields - take her back to midnight! */
 271                 tm_time.tm_sec = 0;
 272                 tm_time.tm_min = 0;
 273                 tm_time.tm_hour = 0;
 274
 275                 /* Process any date input to UNIX time since 1 Jan 1970 */
 276                 if (ENABLE_FEATURE_DATE_ISOFMT && (opt & OPT_STR2DT)) {
 277                         if (strptime(date_str, fmt_str2dt, &tm_time) == NULL)
 278                                 bb_error_msg_and_die(bb_msg_invalid_date, date_str);
 279                 } else {
 280                         check_dst = parse_datestr(date_str, &tm_time);
 281                 }
 282
 283                 /* Correct any day of week and day of year etc. fields */
 284                 /* Be sure to recheck dst (but not if date is UTC) */
 285                 if (check_dst)
 286                         tm_time.tm_isdst = -1;
 287                 ts.tv_sec = validate_tm_time(date_str, &tm_time);
 288                 ts.tv_nsec = 0;
 289
 290                 /* if setting time, set it */
 291                 if ((opt & OPT_SET) && clock_settime(CLOCK_REALTIME, &ts) < 0) {
 292                         bb_simple_perror_msg("can't set date");
 293                 }
 294         }
 295
 296         /* Display output */
 297
 298         /* Deal with format string */
 299         if (fmt_dt2str == NULL) {
 300                 int i;
 301                 fmt_dt2str = buf_fmt_dt2str;
 302                 if (ENABLE_FEATURE_DATE_ISOFMT && isofmt >= 0) {
 303                         /* -I[SPEC]: 0:date 1:hours 2:minutes 3:seconds 4:ns*/
 304                         strcpy(fmt_dt2str, "%Y-%m-%dT%H:%M:%S");
 305                         i = 8 + 3 * isofmt;
 306                         if (isofmt != 0) {
 307                                 int n;
 308                                 if (isofmt == 4) {
 309                                         i -= 3;
 310                                         i += sprintf(&fmt_dt2str[i], ",%09u", (unsigned)ts.tv_nsec);
 311                                 }
 312                                 /* %z prints "+hhmm" timezone, but coreutils-8.30 prints "+hh:mm"! */
 313                                 /* ...therefore this atrocity: */
 314                                 n = strftime(&fmt_dt2str[i], 8, "%z", &tm_time);
 315                                 i += n;
 316                                 if (n == 5 && (fmt_dt2str[i-5] == '+' || fmt_dt2str[i-5] == '-')) {
 317                                         /* "mm" -> ":mm" */
 318                                         fmt_dt2str[i    ] = fmt_dt2str[i - 1];
 319                                         fmt_dt2str[i - 1] = fmt_dt2str[i - 2];
 320                                         fmt_dt2str[i - 2] = ':';
 321                                         i++;
 322                                 }
 323                         }
 324                         fmt_dt2str[i] = '\0';
 325                 } else if (opt & OPT_RFC2822) {
 326                         /* -R. undo busybox.c setlocale */
 327                         if (ENABLE_LOCALE_SUPPORT)
 328                                 setlocale(LC_TIME, "C");
 329                         fmt_dt2str = (char*)"%a, %d %b %Y %H:%M:%S %z";
 330                 } else { /* default case */
 331                         fmt_dt2str = (char*)"%a %b %e %H:%M:%S %Z %Y";
 332                 }
 333         }
 334 #if ENABLE_FEATURE_DATE_NANO
 335         else {
 336                 /* User-specified fmt_dt2str */
 337                 /* Search for and process "%N" */
 338                 char *p = fmt_dt2str;
 339                 while ((p = strchr(p, '%')) != NULL) {
 340                         int n, m;
 341                         unsigned pres, scale;
 342
 343                         p++;
 344                         if (*p == '%') {
 345                                 p++;
 346                                 continue;
 347                         }
 348                         n = strspn(p, "0123456789");
 349                         if (p[n] != 'N') {
 350                                 p += n;
 351                                 continue;
 352                         }
 353                         /* We have "%[nnn]N" */
 354                         p[-1] = '\0';
 355                         p[n] = '\0';
 356                         scale = 1;
 357                         pres = 9;
 358                         if (n) {
 359                                 pres = xatoi_positive(p);
 360                                 if (pres == 0)
 361                                         pres = 9;
 362                                 m = 9 - pres;
 363                                 while (--m >= 0)
 364                                         scale *= 10;
 365                         }
 366
 367                         m = p - fmt_dt2str;
 368                         p += n + 1;
 369                         fmt_dt2str = xasprintf("%s%0*u%s", fmt_dt2str, pres, (unsigned)ts.tv_nsec / scale, p);
 370                         p = fmt_dt2str + m;
 371                 }
 372         }
 373 #endif
 374
 375 #define date_buf bb_common_bufsiz1
 376         setup_common_bufsiz();
 377         if (*fmt_dt2str == '\0') {
 378                 /* With no format string, just print a blank line */
 379                 date_buf[0] = '\0';
 380         } else {
 381                 /* Generate output string */
 382                 strftime(date_buf, COMMON_BUFSIZE, fmt_dt2str, &tm_time);
 383         }
 384         puts(date_buf);
 385
 386         return EXIT_SUCCESS;
 387 }