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+/* date - print or set the system date and time
+ Copyright (C) 1989-2022 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+ David MacKenzie <djm@gnu.ai.mit.edu> */
+
+#include <config.h>
+#include <stdio.h>
+#include <getopt.h>
+#include <sys/types.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+
+#include "system.h"
+#include "argmatch.h"
+#include "die.h"
+#include "error.h"
+#include "parse-datetime.h"
+#include "posixtm.h"
+#include "quote.h"
+#include "stat-time.h"
+#include "fprintftime.h"
+
+/* The official name of this program (e.g., no 'g' prefix). */
+#define PROGRAM_NAME "date"
+
+#define AUTHORS proper_name ("David MacKenzie")
+
+static bool show_date (char const *, struct timespec, timezone_t);
+
+enum Time_spec
+{
+ /* Display only the date. */
+ TIME_SPEC_DATE,
+ /* Display date, hours, minutes, and seconds. */
+ TIME_SPEC_SECONDS,
+ /* Similar, but display nanoseconds. */
+ TIME_SPEC_NS,
+
+ /* Put these last, since they aren't valid for --rfc-3339. */
+
+ /* Display date and hour. */
+ TIME_SPEC_HOURS,
+ /* Display date, hours, and minutes. */
+ TIME_SPEC_MINUTES
+};
+
+static char const *const time_spec_string[] =
+{
+ /* Put "hours" and "minutes" first, since they aren't valid for
+ --rfc-3339. */
+ "hours", "minutes",
+ "date", "seconds", "ns", NULL
+};
+static enum Time_spec const time_spec[] =
+{
+ TIME_SPEC_HOURS, TIME_SPEC_MINUTES,
+ TIME_SPEC_DATE, TIME_SPEC_SECONDS, TIME_SPEC_NS
+};
+ARGMATCH_VERIFY (time_spec_string, time_spec);
+
+/* A format suitable for Internet RFCs 5322, 2822, and 822. */
+static char const rfc_email_format[] = "%a, %d %b %Y %H:%M:%S %z";
+
+/* For long options that have no equivalent short option, use a
+ non-character as a pseudo short option, starting with CHAR_MAX + 1. */
+enum
+{
+ DEBUG_DATE_PARSING_OPTION = CHAR_MAX + 1,
+ RESOLUTION_OPTION,
+ RFC_3339_OPTION
+};
+
+static char const short_options[] = "d:f:I::r:Rs:u";
+
+static struct option const long_options[] =
+{
+ {"date", required_argument, NULL, 'd'},
+ {"debug", no_argument, NULL, DEBUG_DATE_PARSING_OPTION},
+ {"file", required_argument, NULL, 'f'},
+ {"iso-8601", optional_argument, NULL, 'I'},
+ {"reference", required_argument, NULL, 'r'},
+ {"resolution", no_argument, NULL, RESOLUTION_OPTION},
+ {"rfc-email", no_argument, NULL, 'R'},
+ {"rfc-822", no_argument, NULL, 'R'},
+ {"rfc-2822", no_argument, NULL, 'R'},
+ {"rfc-3339", required_argument, NULL, RFC_3339_OPTION},
+ {"set", required_argument, NULL, 's'},
+ {"uct", no_argument, NULL, 'u'},
+ {"utc", no_argument, NULL, 'u'},
+ {"universal", no_argument, NULL, 'u'},
+ {GETOPT_HELP_OPTION_DECL},
+ {GETOPT_VERSION_OPTION_DECL},
+ {NULL, 0, NULL, 0}
+};
+
+/* flags for parse_datetime2 */
+static unsigned int parse_datetime_flags;
+
+#if LOCALTIME_CACHE
+# define TZSET tzset ()
+#else
+# define TZSET /* empty */
+#endif
+
+#ifdef _DATE_FMT
+# define DATE_FMT_LANGINFO() nl_langinfo (_DATE_FMT)
+#else
+# define DATE_FMT_LANGINFO() ""
+#endif
+
+void
+usage (int status)
+{
+ if (status != EXIT_SUCCESS)
+ emit_try_help ();
+ else
+ {
+ printf (_("\
+Usage: %s [OPTION]... [+FORMAT]\n\
+ or: %s [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]\n\
+"),
+ program_name, program_name);
+ fputs (_("\
+Display date and time in the given FORMAT.\n\
+With -s, or with [MMDDhhmm[[CC]YY][.ss]], set the date and time.\n\
+"), stdout);
+
+ emit_mandatory_arg_note ();
+
+ fputs (_("\
+ -d, --date=STRING display time described by STRING, not 'now'\n\
+"), stdout);
+ fputs (_("\
+ --debug annotate the parsed date,\n\
+ and warn about questionable usage to stderr\n\
+"), stdout);
+ fputs (_("\
+ -f, --file=DATEFILE like --date; once for each line of DATEFILE\n\
+"), stdout);
+ fputs (_("\
+ -I[FMT], --iso-8601[=FMT] output date/time in ISO 8601 format.\n\
+ FMT='date' for date only (the default),\n\
+ 'hours', 'minutes', 'seconds', or 'ns'\n\
+ for date and time to the indicated precision.\n\
+ Example: 2006-08-14T02:34:56-06:00\n\
+"), stdout);
+ fputs (_("\
+ --resolution output the available resolution of timestamps\n\
+ Example: 0.000000001\n\
+"), stdout);
+ fputs (_("\
+ -R, --rfc-email output date and time in RFC 5322 format.\n\
+ Example: Mon, 14 Aug 2006 02:34:56 -0600\n\
+"), stdout);
+ fputs (_("\
+ --rfc-3339=FMT output date/time in RFC 3339 format.\n\
+ FMT='date', 'seconds', or 'ns'\n\
+ for date and time to the indicated precision.\n\
+ Example: 2006-08-14 02:34:56-06:00\n\
+"), stdout);
+ fputs (_("\
+ -r, --reference=FILE display the last modification time of FILE\n\
+"), stdout);
+ fputs (_("\
+ -s, --set=STRING set time described by STRING\n\
+ -u, --utc, --universal print or set Coordinated Universal Time (UTC)\n\
+"), stdout);
+ fputs (HELP_OPTION_DESCRIPTION, stdout);
+ fputs (VERSION_OPTION_DESCRIPTION, stdout);
+ fputs (_("\
+\n\
+FORMAT controls the output. Interpreted sequences are:\n\
+\n\
+ %% a literal %\n\
+ %a locale's abbreviated weekday name (e.g., Sun)\n\
+"), stdout);
+ fputs (_("\
+ %A locale's full weekday name (e.g., Sunday)\n\
+ %b locale's abbreviated month name (e.g., Jan)\n\
+ %B locale's full month name (e.g., January)\n\
+ %c locale's date and time (e.g., Thu Mar 3 23:05:25 2005)\n\
+"), stdout);
+ fputs (_("\
+ %C century; like %Y, except omit last two digits (e.g., 20)\n\
+ %d day of month (e.g., 01)\n\
+ %D date; same as %m/%d/%y\n\
+ %e day of month, space padded; same as %_d\n\
+"), stdout);
+ fputs (_("\
+ %F full date; like %+4Y-%m-%d\n\
+ %g last two digits of year of ISO week number (see %G)\n\
+ %G year of ISO week number (see %V); normally useful only with %V\n\
+"), stdout);
+ fputs (_("\
+ %h same as %b\n\
+ %H hour (00..23)\n\
+ %I hour (01..12)\n\
+ %j day of year (001..366)\n\
+"), stdout);
+ fputs (_("\
+ %k hour, space padded ( 0..23); same as %_H\n\
+ %l hour, space padded ( 1..12); same as %_I\n\
+ %m month (01..12)\n\
+ %M minute (00..59)\n\
+"), stdout);
+ fputs (_("\
+ %n a newline\n\
+ %N nanoseconds (000000000..999999999)\n\
+ %p locale's equivalent of either AM or PM; blank if not known\n\
+ %P like %p, but lower case\n\
+ %q quarter of year (1..4)\n\
+ %r locale's 12-hour clock time (e.g., 11:11:04 PM)\n\
+ %R 24-hour hour and minute; same as %H:%M\n\
+ %s seconds since the Epoch (1970-01-01 00:00 UTC)\n\
+"), stdout);
+ fputs (_("\
+ %S second (00..60)\n\
+ %t a tab\n\
+ %T time; same as %H:%M:%S\n\
+ %u day of week (1..7); 1 is Monday\n\
+"), stdout);
+ fputs (_("\
+ %U week number of year, with Sunday as first day of week (00..53)\n\
+ %V ISO week number, with Monday as first day of week (01..53)\n\
+ %w day of week (0..6); 0 is Sunday\n\
+ %W week number of year, with Monday as first day of week (00..53)\n\
+"), stdout);
+ fputs (_("\
+ %x locale's date representation (e.g., 12/31/99)\n\
+ %X locale's time representation (e.g., 23:13:48)\n\
+ %y last two digits of year (00..99)\n\
+ %Y year\n\
+"), stdout);
+ fputs (_("\
+ %z +hhmm numeric time zone (e.g., -0400)\n\
+ %:z +hh:mm numeric time zone (e.g., -04:00)\n\
+ %::z +hh:mm:ss numeric time zone (e.g., -04:00:00)\n\
+ %:::z numeric time zone with : to necessary precision (e.g., -04, +05:30)\n\
+ %Z alphabetic time zone abbreviation (e.g., EDT)\n\
+\n\
+By default, date pads numeric fields with zeroes.\n\
+"), stdout);
+ fputs (_("\
+The following optional flags may follow '%':\n\
+\n\
+ - (hyphen) do not pad the field\n\
+ _ (underscore) pad with spaces\n\
+ 0 (zero) pad with zeros\n\
+ + pad with zeros, and put '+' before future years with >4 digits\n\
+ ^ use upper case if possible\n\
+ # use opposite case if possible\n\
+"), stdout);
+ fputs (_("\
+\n\
+After any flags comes an optional field width, as a decimal number;\n\
+then an optional modifier, which is either\n\
+E to use the locale's alternate representations if available, or\n\
+O to use the locale's alternate numeric symbols if available.\n\
+"), stdout);
+ fputs (_("\
+\n\
+Examples:\n\
+Convert seconds since the Epoch (1970-01-01 UTC) to a date\n\
+ $ date --date='@2147483647'\n\
+\n\
+Show the time on the west coast of the US (use tzselect(1) to find TZ)\n\
+ $ TZ='America/Los_Angeles' date\n\
+\n\
+Show the local time for 9AM next Friday on the west coast of the US\n\
+ $ date --date='TZ=\"America/Los_Angeles\" 09:00 next Fri'\n\
+"), stdout);
+ emit_ancillary_info (PROGRAM_NAME);
+ }
+ exit (status);
+}
+
+/* Yield the number of decimal digits needed to output a time with the
+ nanosecond resolution RES, without losing information. */
+
+static int
+res_width (long int res)
+{
+ int i = 9;
+ for (long long int r = 1; (r *= 10) <= res; )
+ i--;
+ return i;
+}
+
+/* Return a newly allocated copy of FORMAT with each "%-N" adjusted to
+ be "%9N", "%6N", or whatever other resolution is appropriate for
+ the current platform. If no "%-N" appears, return NULL. */
+
+static char *
+adjust_resolution (char const *format)
+{
+ char *copy = NULL;
+
+ for (char const *f = format; *f; f++)
+ if (f[0] == '%')
+ {
+ if (f[1] == '-' && f[2] == 'N')
+ {
+ if (!copy)
+ copy = xstrdup (format);
+ copy[f + 1 - format] = '0' + res_width (gettime_res ());
+ f += 2;
+ }
+ else
+ f += f[1] == '%';
+ }
+
+ return copy;
+}
+
+/* Parse each line in INPUT_FILENAME as with --date and display each
+ resulting time and date. If the file cannot be opened, tell why
+ then exit. Issue a diagnostic for any lines that cannot be parsed.
+ Return true if successful. */
+
+static bool
+batch_convert (char const *input_filename, char const *format,
+ timezone_t tz, char const *tzstring)
+{
+ bool ok;
+ FILE *in_stream;
+ char *line;
+ size_t buflen;
+ struct timespec when;
+
+ if (STREQ (input_filename, "-"))
+ {
+ input_filename = _("standard input");
+ in_stream = stdin;
+ }
+ else
+ {
+ in_stream = fopen (input_filename, "r");
+ if (in_stream == NULL)
+ {
+ die (EXIT_FAILURE, errno, "%s", quotef (input_filename));
+ }
+ }
+
+ line = NULL;
+ buflen = 0;
+ ok = true;
+ while (true)
+ {
+ ssize_t line_length = getline (&line, &buflen, in_stream);
+ if (line_length < 0)
+ {
+ /* FIXME: detect/handle error here. */
+ break;
+ }
+
+ if (! parse_datetime2 (&when, line, NULL,
+ parse_datetime_flags, tz, tzstring))
+ {
+ if (line[line_length - 1] == '\n')
+ line[line_length - 1] = '\0';
+ error (0, 0, _("invalid date %s"), quote (line));
+ ok = false;
+ }
+ else
+ {
+ ok &= show_date (format, when, tz);
+ }
+ }
+
+ if (fclose (in_stream) == EOF)
+ die (EXIT_FAILURE, errno, "%s", quotef (input_filename));
+
+ free (line);
+
+ return ok;
+}
+
+int
+main (int argc, char **argv)
+{
+ int optc;
+ char const *datestr = NULL;
+ char const *set_datestr = NULL;
+ struct timespec when;
+ bool set_date = false;
+ char const *format = NULL;
+ bool get_resolution = false;
+ char *batch_file = NULL;
+ char *reference = NULL;
+ struct stat refstats;
+ bool ok;
+
+ initialize_main (&argc, &argv);
+ set_program_name (argv[0]);
+ setlocale (LC_ALL, "");
+ bindtextdomain (PACKAGE, LOCALEDIR);
+ textdomain (PACKAGE);
+
+ atexit (close_stdout);
+
+ while ((optc = getopt_long (argc, argv, short_options, long_options, NULL))
+ != -1)
+ {
+ char const *new_format = NULL;
+
+ switch (optc)
+ {
+ case 'd':
+ datestr = optarg;
+ break;
+ case DEBUG_DATE_PARSING_OPTION:
+ parse_datetime_flags |= PARSE_DATETIME_DEBUG;
+ break;
+ case 'f':
+ batch_file = optarg;
+ break;
+ case RESOLUTION_OPTION:
+ get_resolution = true;
+ break;
+ case RFC_3339_OPTION:
+ {
+ static char const rfc_3339_format[][32] =
+ {
+ "%Y-%m-%d",
+ "%Y-%m-%d %H:%M:%S%:z",
+ "%Y-%m-%d %H:%M:%S.%N%:z"
+ };
+ enum Time_spec i =
+ XARGMATCH ("--rfc-3339", optarg,
+ time_spec_string + 2, time_spec + 2);
+ new_format = rfc_3339_format[i];
+ break;
+ }
+ case 'I':
+ {
+ static char const iso_8601_format[][32] =
+ {
+ "%Y-%m-%d",
+ "%Y-%m-%dT%H:%M:%S%:z",
+ "%Y-%m-%dT%H:%M:%S,%N%:z",
+ "%Y-%m-%dT%H%:z",
+ "%Y-%m-%dT%H:%M%:z"
+ };
+ enum Time_spec i =
+ (optarg
+ ? XARGMATCH ("--iso-8601", optarg, time_spec_string, time_spec)
+ : TIME_SPEC_DATE);
+ new_format = iso_8601_format[i];
+ break;
+ }
+ case 'r':
+ reference = optarg;
+ break;
+ case 'R':
+ new_format = rfc_email_format;
+ break;
+ case 's':
+ set_datestr = optarg;
+ set_date = true;
+ break;
+ case 'u':
+ /* POSIX says that 'date -u' is equivalent to setting the TZ
+ environment variable, so this option should do nothing other
+ than setting TZ. */
+ if (putenv (bad_cast ("TZ=UTC0")) != 0)
+ xalloc_die ();
+ TZSET;
+ break;
+ case_GETOPT_HELP_CHAR;
+ case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+ default:
+ usage (EXIT_FAILURE);
+ }
+
+ if (new_format)
+ {
+ if (format)
+ die (EXIT_FAILURE, 0, _("multiple output formats specified"));
+ format = new_format;
+ }
+ }
+
+ int option_specified_date = (!!datestr + !!batch_file + !!reference
+ + get_resolution);
+
+ if (option_specified_date > 1)
+ {
+ error (0, 0,
+ _("the options to specify dates for printing are mutually exclusive"));
+ usage (EXIT_FAILURE);
+ }
+
+ if (set_date && option_specified_date)
+ {
+ error (0, 0,
+ _("the options to print and set the time may not be used together"));
+ usage (EXIT_FAILURE);
+ }
+
+ if (optind < argc)
+ {
+ if (optind + 1 < argc)
+ {
+ error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
+ usage (EXIT_FAILURE);
+ }
+
+ if (argv[optind][0] == '+')
+ {
+ if (format)
+ die (EXIT_FAILURE, 0, _("multiple output formats specified"));
+ format = argv[optind++] + 1;
+ }
+ else if (set_date || option_specified_date)
+ {
+ error (0, 0,
+ _("the argument %s lacks a leading '+';\n"
+ "when using an option to specify date(s), any non-option\n"
+ "argument must be a format string beginning with '+'"),
+ quote (argv[optind]));
+ usage (EXIT_FAILURE);
+ }
+ }
+
+ if (!format)
+ {
+ if (get_resolution)
+ format = "%s.%N";
+ else
+ {
+ format = DATE_FMT_LANGINFO ();
+
+ /* Do not wrap the following literal format string with _(...).
+ For example, suppose LC_ALL is unset, LC_TIME=POSIX,
+ and LANG="ko_KR". In that case, POSIX says that LC_TIME
+ determines the format and contents of date and time strings
+ written by date, which means "date" must generate output
+ using the POSIX locale; but adding _() would cause "date"
+ to use a Korean translation of the format. */
+ if (! *format)
+ format = "%a %b %e %H:%M:%S %Z %Y";
+ }
+ }
+
+ char *format_copy = adjust_resolution (format);
+ char const *format_res = format_copy ? format_copy : format;
+ char const *tzstring = getenv ("TZ");
+ timezone_t tz = tzalloc (tzstring);
+
+ if (batch_file != NULL)
+ ok = batch_convert (batch_file, format_res, tz, tzstring);
+ else
+ {
+ bool valid_date = true;
+ ok = true;
+
+ if (!option_specified_date && !set_date)
+ {
+ if (optind < argc)
+ {
+ /* Prepare to set system clock to the specified date/time
+ given in the POSIX-format. */
+ set_date = true;
+ datestr = argv[optind];
+ valid_date = posixtime (&when.tv_sec,
+ datestr,
+ (PDS_TRAILING_YEAR
+ | PDS_CENTURY | PDS_SECONDS));
+ when.tv_nsec = 0; /* FIXME: posixtime should set this. */
+ }
+ else
+ {
+ /* Prepare to print the current date/time. */
+ gettime (&when);
+ }
+ }
+ else
+ {
+ /* (option_specified_date || set_date) */
+ if (reference != NULL)
+ {
+ if (stat (reference, &refstats) != 0)
+ die (EXIT_FAILURE, errno, "%s", quotef (reference));
+ when = get_stat_mtime (&refstats);
+ }
+ else if (get_resolution)
+ {
+ long int res = gettime_res ();
+ when.tv_sec = res / TIMESPEC_HZ;
+ when.tv_nsec = res % TIMESPEC_HZ;
+ }
+ else
+ {
+ if (set_datestr)
+ datestr = set_datestr;
+ valid_date = parse_datetime2 (&when, datestr, NULL,
+ parse_datetime_flags,
+ tz, tzstring);
+ }
+ }
+
+ if (! valid_date)
+ die (EXIT_FAILURE, 0, _("invalid date %s"), quote (datestr));
+
+ if (set_date)
+ {
+ /* Set the system clock to the specified date, then regardless of
+ the success of that operation, format and print that date. */
+ if (settime (&when) != 0)
+ {
+ error (0, errno, _("cannot set date"));
+ ok = false;
+ }
+ }
+
+ ok &= show_date (format_res, when, tz);
+ }
+
+ main_exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
+}
+
+/* Display the date and/or time in WHEN according to the format specified
+ in FORMAT, followed by a newline. Return true if successful. */
+
+static bool
+show_date (char const *format, struct timespec when, timezone_t tz)
+{
+ struct tm tm;
+
+ if (parse_datetime_flags & PARSE_DATETIME_DEBUG)
+ error (0, 0, _("output format: %s"), quote (format));
+
+ if (localtime_rz (tz, &when.tv_sec, &tm))
+ {
+ if (format == rfc_email_format)
+ setlocale (LC_TIME, "C");
+ fprintftime (stdout, format, &tm, tz, when.tv_nsec);
+ if (format == rfc_email_format)
+ setlocale (LC_TIME, "");
+ fputc ('\n', stdout);
+ return true;
+ }
+ else
+ {
+ char buf[INT_BUFSIZE_BOUND (intmax_t)];
+ error (0, 0, _("time %s is out of range"),
+ quote (timetostr (when.tv_sec, buf)));
+ return false;
+ }
+}