From 79079cdc560d68257c110482c730ab043c7f4c0f Mon Sep 17 00:00:00 2001 From: John Vogel <[email protected]> Date: Thu, 5 May 2016 15:01:36 -0400 Subject: [sbase][Patch] date: add date/time setting capability To: [email protected]
Signed-off-by: John Vogel <[email protected]> --- date.1 | 46 ++++++++++++++++++++++++++++++++++++++++++++-- date.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------- 2 files changed, 102 insertions(+), 9 deletions(-) diff --git a/date.1 b/date.1 index 29081a5..0171936 100644 --- a/date.1 +++ b/date.1 @@ -3,12 +3,15 @@ .Os sbase .Sh NAME .Nm date -.Nd print date and time +.Nd print or set date and time .Sh SYNOPSIS .Nm .Op Fl d Ar time .Op Fl u .Op Cm + Ns Ar format +.Sm off +.Op Ar mmddHHMM Oo Oo Ar CC Oc Ar yy Oc +.Sm on .Sh DESCRIPTION .Nm prints the date and time according to @@ -16,7 +19,8 @@ prints the date and time according to or .Ar format using -.Xr strftime 3 . +.Xr strftime 3 +or sets the date. .Sh OPTIONS .Bl -tag -width Ds .It Fl d Ar time @@ -27,6 +31,44 @@ Unix epoch 1970-01-01T00:00:00Z. .It Fl u Print UTC time instead of local time. .El +.Pp +An operand with a leading plus +.Pq Cm + +sign signals a user-defined format string using +.Xr strftime 3 +conversion specifications. +.Pp +An operand without a leading plus sign is +interpreted a value for setting the systems current date and time. +The canonical representation for setting the date and time is: +.Pp +.Bl -tag -width Ds -compact -offset indent +.It Ar mm +The month of the year, from 01 to 12. +.It Ar dd +The day of the month, from 01 to 31. +.It Ar HH +The hour of the day, from 00 to 23. +.It Ar MM +The minute of the hour, from 00 to 59. +.It Ar CC +The first two digits of the year (the century). +.It Ar yy +The second two digits of the year. +If +.Ar yy +is specified, but +.Ar CC +is not, a value for +.Ar yy +between 69 and 99 results in a +.Ar CC +value of 19. Otherwise, a +.Ar CC +value of 20 is used. +.El +.Pp +The century and year are optional. The default is the current year. .Sh STANDARDS The .Nm diff --git a/date.c b/date.c index 1671e1f..f3db89f 100644 --- a/date.c +++ b/date.c @@ -1,6 +1,8 @@ /* See LICENSE file for copyright and license details. */ #include <stdio.h> #include <stdlib.h> +#include <string.h> +#include <errno.h> #include <time.h> #include "util.h" @@ -8,19 +10,20 @@ static void usage(void) { - eprintf("usage: %s [-u] [-d time] [+format]\n", argv0); + eprintf("usage: %s [-u] [-d time] [+format] [mmddHHMM[[CC]yy]]\n", argv0); } int main(int argc, char *argv[]) { struct tm *now; + struct tm date; struct tm *(*tztime)(const time_t *) = localtime; + struct timespec ts; time_t t; + size_t i, j, len; char buf[BUFSIZ], *fmt = "%c", *tz = "local"; - t = time(NULL); - ARGBEGIN { case 'd': t = estrtonum(EARGF(usage()), 0, LLONG_MAX); @@ -33,14 +36,62 @@ main(int argc, char *argv[]) usage(); } ARGEND + t = time(NULL); + + if (!(now = tztime(&t))) + eprintf("%stime failed\n", tz); + if (argc) { - if (argc != 1 || argv[0][0] != '+') + if (argc != 1) { usage(); - else + } else if (argv[0][0] == '+') { fmt = &argv[0][1]; + } else { + len = strlen(argv[0]); + + switch (len) { + case 8: + fmt = "%m %d %H %M"; + break; + case 10: + fmt = "%m %d %H %M %y"; + break; + case 12: + fmt = "%m %d %H %M %C %y"; + break; + default: + eprintf("invalid date format: %s\n", argv[0]); + } + + /* strptime does not handle the mmddHHMM[[CC]yy] format with + * the leading zeroes for each specifier unless they are separated. + */ + for (i = 0, j = 0; i < len; i++) { + buf[j++] = argv[0][i]; + if (i && i < len-1 && (i%2)) + buf[j++] = ' '; + } + buf[j] = '\0'; + + if (strptime(buf, fmt, &date) == NULL) + eprintf("strptime failed: invalid input: %s\n", argv[0]); + + if (len == 8) + date.tm_year = now->tm_year; + + t = mktime(&date); + if (t == (time_t)-1) + eprintf("mktime failed: bad calendar date/time: %s\n", argv[0]); + + ts.tv_sec = t; + ts.tv_nsec = 0; + + if (clock_settime(CLOCK_REALTIME, &ts) == -1) + eprintf("clock_settime failed: %s\n", strerror(errno)); + + return fshut(stdout, "<stdout>"); + } } - if (!(now = tztime(&t))) - eprintf("%stime failed\n", tz); strftime(buf, sizeof(buf), fmt, now); puts(buf); -- 2.7.4
