On Thu, 29 Dec 2016 12:11:33 +0100 Hiltjo Posthuma <hil...@codemadness.org> wrote:
> Nitpicks: > - Check if digit in date_field(). > - Style: don't declare variables in the inner scope, just use the > function scope for struct tm date; and struct timespec ts; > > Kind regards, > Hiltjo > Thanks for your input. -- >8 -- date.1 | 46 ++++++++++++++++++++++++++++++++++++++-- date.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------- 2 files changed, 112 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..bf377c7 100644 --- a/date.c +++ b/date.c @@ -1,6 +1,9 @@ /* See LICENSE file for copyright and license details. */ #include <stdio.h> #include <stdlib.h> +#include <ctype.h> +#include <string.h> +#include <errno.h> #include <time.h> #include "util.h" @@ -8,7 +11,15 @@ 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); +} + +static int +date_field(const char *s, size_t i) +{ + if (isdigit(s[i]) && isdigit(s[i+1])) + return (s[i] - '0') * 10 + (s[i+1] - '0'); + return -1; } int @@ -16,11 +27,12 @@ main(int argc, char *argv[]) { struct tm *now; struct tm *(*tztime)(const time_t *) = localtime; + struct tm date; + struct timespec ts; time_t t; + int century, year; char buf[BUFSIZ], *fmt = "%c", *tz = "local"; - t = time(NULL); - ARGBEGIN { case 'd': t = estrtonum(EARGF(usage()), 0, LLONG_MAX); @@ -33,14 +45,63 @@ main(int argc, char *argv[]) usage(); } ARGEND + t = time(NULL); + if (t == (time_t)-1) + eprintf("time failed:"); + + 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 { + switch (strlen(argv[0])) { + case 8: + date.tm_year = now->tm_year; + break; + case 10: + date.tm_year = date_field(argv[0], 8); + if ((date.tm_year >= 0) && (date.tm_year < 69)) + date.tm_year += 100; + break; + case 12: + century = date_field(argv[0], 8); + year = date_field(argv[0], 10); + if ((century >= 0) && (year >= 0)) { + date.tm_year = ((century - 19) * 100) + year; + break; + } + /* fallthrough */ + default: + date.tm_year = -1; + break; + } + + if ((date.tm_year < 0) || + ((date.tm_mon = date_field(argv[0], 0)) < 0) || + ((date.tm_mday = date_field(argv[0], 2)) < 0) || + ((date.tm_hour = date_field(argv[0], 4)) < 0) || + ((date.tm_min = date_field(argv[0], 6)) < 0)) + eprintf("invalid date format: %s\n", argv[0]); + + date.tm_mon--; + + t = mktime(&date); + if (t == (time_t)-1) + eprintf("mktime failed: bad calender 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:"); + + return 0; + } } - if (!(now = tztime(&t))) - eprintf("%stime failed\n", tz); strftime(buf, sizeof(buf), fmt, now); puts(buf);