+//config:config DATE
+//config: bool "date (7 kb)"
+//config: default y
+//config: help
+//config: date is used to set the system date or display the
+//config: current time in the given format.
+//config:
+//config:config FEATURE_DATE_ISOFMT
+//config: bool "Enable ISO date format output (-I)"
+//config: default y
+//config: depends on DATE
+//config: help
+//config: Enable option (-I) to output an ISO-8601 compliant
+//config: date/time string.
+//config:
+//config:config FEATURE_DATE_NANO
+//config: bool "Support %[num]N nanosecond format specifier"
+//config: default n # stat's nanosecond field is a bit non-portable
+//config: depends on DATE
+//config: select PLATFORM_LINUX
+//config: help
+//config: Support %[num]N format specifier. Adds ~250 bytes of code.
+//config:
+//config:config FEATURE_DATE_COMPAT
+//config: bool "Support weird 'date MMDDhhmm[[YY]YY][.ss]' format"
+//config: default y
+//config: depends on DATE
+//config: help
+//config: System time can be set by 'date -s DATE' and simply 'date DATE',
+//config: but formats of DATE string are different. 'date DATE' accepts
+//config: a rather weird MMDDhhmm[[YY]YY][.ss] format with completely
+//config: unnatural placement of year between minutes and seconds.
+//config: date -s (and other commands like touch -d) use more sensible
+//config: formats (for one, ISO format YYYY-MM-DD hh:mm:ss.ssssss).
+//config:
+//config: With this option off, 'date DATE' and 'date -s DATE' support
+//config: the same format. With it on, 'date DATE' additionally supports
+//config: MMDDhhmm[[YY]YY][.ss] format.
+
+//applet:IF_DATE(APPLET_NOEXEC(date, date, BB_DIR_BIN, BB_SUID_DROP, date))
+/* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
+
+//kbuild:lib-$(CONFIG_DATE) += date.o
+
+/* GNU coreutils 6.9 man page:
+ * date [OPTION]... [+FORMAT]
+ * date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]
+ * -d, --date=STRING
+ * display time described by STRING, not 'now'
+ * -f, --file=DATEFILE
+ * like --date once for each line of DATEFILE
+ * -r, --reference=FILE
+ * display the last modification time of FILE
+ * -R, --rfc-2822
+ * output date and time in RFC 2822 format.
+ * Example: Mon, 07 Aug 2006 12:34:56 -0600
+ * --rfc-3339=TIMESPEC
+ * output date and time in RFC 3339 format.
+ * TIMESPEC='date', 'seconds', or 'ns'
+ * Date and time components are separated by a single space:
+ * 2006-08-07 12:34:56-06:00
+ * -s, --set=STRING
+ * set time described by STRING
+ * -u, --utc, --universal
+ * print or set Coordinated Universal Time
+ *
+ * Busybox:
+ * long options are not supported
+ * -f is not supported
+ * -I seems to roughly match --rfc-3339, but -I has _optional_ param
+ * (thus "-I seconds" doesn't work, only "-Iseconds"),
+ * and does not support -Ins
+ * -D FMT is a bbox extension for _input_ conversion of -d DATE
+ */
+
+//usage:#define date_trivial_usage
+//usage: "[OPTIONS] [+FMT] [TIME]"
+//usage:#define date_full_usage "\n\n"
+//usage: "Display time (using +FMT), or set time\n"
+//usage: IF_NOT_LONG_OPTS(
+//usage: "\n [-s] TIME Set time to TIME"
+//usage: "\n -u Work in UTC (don't convert to local time)"
+//usage: "\n -R Output RFC-2822 compliant date string"
+//usage: ) IF_LONG_OPTS(
+//usage: "\n [-s,--set] TIME Set time to TIME"
+//usage: "\n -u,--utc Work in UTC (don't convert to local time)"
+//usage: "\n -R,--rfc-2822 Output RFC-2822 compliant date string"
+//usage: )
+//usage: IF_FEATURE_DATE_ISOFMT(
+//usage: "\n -I[SPEC] Output ISO-8601 compliant date string"
+//usage: "\n SPEC='date' (default) for date only,"
+//usage: "\n 'hours', 'minutes', or 'seconds' for date and"
+//usage: "\n time to the indicated precision"
+//usage: )
+//usage: IF_NOT_LONG_OPTS(
+//usage: "\n -r FILE Display last modification time of FILE"
+//usage: "\n -d TIME Display TIME, not 'now'"
+//usage: ) IF_LONG_OPTS(
+//usage: "\n -r,--reference FILE Display last modification time of FILE"
+//usage: "\n -d,--date TIME Display TIME, not 'now'"
+//usage: )
+//usage: IF_FEATURE_DATE_ISOFMT(
+//usage: "\n -D FMT Use FMT (strptime format) for -d TIME conversion"
+//usage: )
+//usage: "\n"
+//usage: "\nRecognized TIME formats:"
+//usage: "\n hh:mm[:ss]"
+//usage: "\n [YYYY.]MM.DD-hh:mm[:ss]"
+//usage: "\n YYYY-MM-DD hh:mm[:ss]"
+//usage: "\n [[[[[YY]YY]MM]DD]hh]mm[.ss]"
+//usage: IF_FEATURE_DATE_COMPAT(
+//usage: "\n 'date TIME' form accepts MMDDhhmm[[YY]YY][.ss] instead"
+//usage: )
+//usage:
+//usage:#define date_example_usage
+//usage: "$ date\n"
+//usage: "Wed Apr 12 18:52:41 MDT 2000\n"
+
+#include "libbb.h"
+#include "common_bufsiz.h"
+#if ENABLE_FEATURE_DATE_NANO
+# include <sys/syscall.h>
+#endif
+
+enum {
+ OPT_RFC2822 = (1 << 0), /* R */
+ OPT_SET = (1 << 1), /* s */
+ OPT_UTC = (1 << 2), /* u */
+ OPT_DATE = (1 << 3), /* d */
+ OPT_REFERENCE = (1 << 4), /* r */
+ OPT_TIMESPEC = (1 << 5) * ENABLE_FEATURE_DATE_ISOFMT, /* I */
+ OPT_HINT = (1 << 6) * ENABLE_FEATURE_DATE_ISOFMT, /* D */
+};