/* date.c - set/get the date
*
* Copyright 2012 Andre Renaud <andre@bluewatersys.com>
*
* See http://opengroup.org/onlinepubs/9699919799/utilities/date.html
*
* Note: setting a 2 year date is 50 years back/forward from today,
* not posix's hardwired magic dates.
USE_DATE(NEWTOY(date, "d:D:r:u[!dr]", TOYFLAG_BIN))
config DATE
bool "date"
default y
help
usage: date [-u] [-r FILE] [-d DATE] [+DISPLAY_FORMAT] [-D SET_FORMAT] [SET]
Set/get the current date/time. With no SET shows the current date.
Default SET format is "MMDDhhmm[[CC]YY][.ss]", that's (2 digits each)
month, day, hour (0-23), and minute. Optionally century, year, and second.
Also accepts "@UNIXTIME[.FRACTION]" as seconds since midnight Jan 1 1970.
-d Show DATE instead of current time (convert date format)
-D +FORMAT for SET or -d (instead of MMDDhhmm[[CC]YY][.ss])
-r Use modification time of FILE instead of current date
-u Use UTC instead of current timezone
+FORMAT specifies display format string using these escapes:
%% literal % %n newline %t tab
%S seconds (00-60) %M minute (00-59) %m month (01-12)
%H hour (0-23) %I hour (01-12) %p AM/PM
%y short year (00-99) %Y year %C century
%a short weekday name %A weekday name %u day of week (1-7, 1=mon)
%b short month name %B month name %Z timezone name
%j day of year (001-366) %d day of month (01-31) %e day of month ( 1-31)
%s seconds past the Epoch
%U Week of year (0-53 start sunday) %W Week of year (0-53 start monday)
%V Week of year (1-53 start monday, week < 4 days not part of this year)
%D = "%m/%d/%y" %r = "%I : %M : %S %p" %T = "%H:%M:%S" %h = "%b"
%x locale date %X locale time %c locale date/time
*/
#define FOR_date
#include "toys.h"
GLOBALS(
char *file;
char *setfmt;
char *showdate;
char *tz;
unsigned nano;
)
// mktime(3) normalizes the struct tm fields, but date(1) shouldn't.
static time_t chkmktime(struct tm *tm, const char *str, const char* fmt)
{
struct tm tm0 = *tm;
struct tm tm1;
time_t t = mktime(tm);
if (t == -1 || !localtime_r(&t, &tm1) ||
tm0.tm_sec != tm1.tm_sec || tm0.tm_min != tm1.tm_min ||
tm0.tm_hour != tm1.tm_hour || tm0.tm_mday != tm1.tm_mday ||
tm0.tm_mon != tm1.tm_mon) {
int len;
strftime(toybuf, sizeof(toybuf), fmt, &tm0);
len = strlen(toybuf) + 1;
strftime(toybuf + len, sizeof(toybuf) - len, fmt, &tm1);
error_exit("bad date '%s'; %s != %s", str, toybuf, toybuf + len);
}
return t;
}
static void utzset(void)
{
if (!(TT.tz = getenv("TZ"))) TT.tz = (char *)1;
setenv("TZ", "UTC", 1);
tzset();
}
static void utzreset(void)
{
if (TT.tz) {
if (TT.tz != (char *)1) setenv("TZ", TT.tz, 1);
else unsetenv("TZ");
tzset();
}
}
// Handle default posix date format (mmddhhmm[[cc]yy]) or @UNIX[.FRAC]
// returns 0 success, nonzero for error
static int parse_default(char *str, struct tm *tm)
{
int len = 0;
// Parse @UNIXTIME[.FRACTION]
if (*str == '@') {
long long ll;
time_t tt;
// Collect seconds and nanoseconds
// Note: struct tm hasn't got a fractional seconds field, thus strptime()
// doesn't support it, so store nanoseconds out of band (in globals).
// tt and ll are separate because we can't guarantee time_t is 64 bit (yet).
sscanf(str, "@%lld%n", &ll, &len);
if (str[len]=='.') {
str += len+1;
for (len = 0; len<9; len++) {
TT.nano *= 10;
if (isdigit(str[len])) TT.nano += str[len]-'0';
}
}
if (str[len]) return 1;
tt = ll;
gmtime_r(&tt, tm);
return 0;
}
// Posix format
sscanf(str, "%2u%2u%2u%2u%n", &tm->tm_mon, &tm->tm_mday, &tm->tm_hour,
&tm->tm_min, &len);
if (len != 8) return 1;
str += len;
tm->tm_mon--;
// If year specified, overwrite one we fetched earlier
if (*str && *str != '.') {
unsigned year;
len = 0;
sscanf(str, "%u%n", &year, &len);
if (len == 4) tm->tm_year = year - 1900;
else if (len != 2) return 1;
str += len;
// 2 digit years, next 50 years are "future", last 50 years are "past".
// A "future" date in past is a century ahead.
// A non-future date in the future is a century behind.
if (len == 2) {
unsigned r1 = tm->tm_year % 100, r2 = (tm->tm_year + 50) % 100,
century = tm->tm_year - r1;
if ((r1 < r2) ? (r1 < year && year < r2) : (year < r1 || year > r2)) {
if (year < r1) year += 100;
} else if (year > r1) year -= 100;
tm->tm_year = year + century;
}
}
if (*str == '.') {
len = 0;
sscanf(str, ".%u%n", &tm->tm_sec, &len);
str += len;
} else tm->tm_sec = 0;
return *str;
}
void date_main(void)
{
char *setdate = *toys.optargs, *format_string = "%a %b %e %H:%M:%S %Z %Y";
struct tm tm;
memset(&tm, 0, sizeof(struct tm));
// We can't just pass a timezone to mktime because posix.
if (toys.optflags & FLAG_u) utzset();
if (TT.showdate) {
if (TT.setfmt) {
char *s = strptime(TT.showdate, TT.setfmt+(*TT.setfmt=='+'), &tm);
if (!s || *s) goto bad_showdate;
} else if (parse_default(TT.showdate, &tm)) goto bad_showdate;
} else {
time_t now;
if (TT.file) {
struct stat st;
xstat(TT.file, &st);
now = st.st_mtim.tv_sec;
} else now = time(0);
((toys.optflags & FLAG_u) ? gmtime_r : localtime_r)(&now, &tm);
}
// Fall through if no arguments
if (!setdate);
// Display the date?
else if (*setdate == '+') {
format_string = toys.optargs[0]+1;
setdate = toys.optargs[1];
// Set the date
} else if (setdate) {
struct timeval tv;
if (parse_default(setdate, &tm)) error_exit("bad date '%s'", setdate);
if (toys.optflags & FLAG_u) {
// We can't just pass a timezone to mktime because posix.
utzset();
tv.tv_sec = chkmktime(&tm, setdate, format_string);
utzreset();
} else tv.tv_sec = chkmktime(&tm, setdate, format_string);
tv.tv_usec = TT.nano/1000;
if (settimeofday(&tv, NULL) < 0) perror_msg("cannot set date");
}
utzreset();
if (!strftime(toybuf, sizeof(toybuf), format_string, &tm))
perror_exit("bad format '%s'", format_string);
puts(toybuf);
return;
bad_showdate:
error_exit("bad date '%s'", TT.showdate);
}