utils

commit: 3f5c37ade3b274a4b5fb4414de9d01afaa08c653
parent 445d7356995342567674646f51dd37cb4effbcd8
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Fri, 11 Mar 2022 17:32:40 +0100

bin/date: Add support for setting a custom datetime

Diffstat:
M
bin/date.1
6
+++++-
M
bin/date.c
57
++++++++++++++++++++++++++++++++++++++++++++++++---------
M
test-bin/date
16
+++++++++++++---

3 files changed, 66 insertions(+), 13 deletions(-)
diff --git a/bin/date.1 b/bin/date.1
@@ -1,7 +1,7 @@
 .\" Collection of Unix tools, comparable to coreutils
 .\" Copyright 2017-2022 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
 .\" SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
-.Dd 2018-10-15
+.Dd 2022-03-11
 .Dt DATE 1
 .Os
 .Sh NAME
@@ -10,6 +10,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl u
+.Op Fl d Ar datetime
 .Op Cm + Ns Ar format
 .Sh DESCRIPTION
 When
@@ -17,6 +18,9 @@ When
 is invoked without arguments it displays the current datetime
 Otherwise, depending on the options specified, will print the datetime in a user-defined way.
 .Bl -tag -width Ds
+.It Fl d Ar datetime
+.Ar datetime
+can contain the Unix timestamp (number of seconds before and after 1970-01-01T00:00:00Z) prefixed by an @ (at) symbol.
 .It Fl u
 Use UTC (coordinated universal time) instead of the local time.
 .El
diff --git a/bin/date.c b/bin/date.c
@@ -6,9 +6,34 @@
 #include <errno.h>  /* errno */
 #include <locale.h> /* setlocale() */
 #include <stdio.h>  /* BUFSIZ, perror(), puts() */
-#include <stdlib.h> /* exit() */
+#include <stdlib.h> /* exit(), strtol() */
 #include <time.h>   /* time, localtime, tm, strftime */
 #include <unistd.h> /* getopt(), optarg, optind */
+#include <errno.h>  /* errno */
+
+int
+custom_datetime(time_t *now, char *optarg)
+{
+	if(optarg[0] == '@') {
+		optarg++;
+		errno = 0;
+		*now = (time_t)strtol(optarg, NULL, 10);
+		if(errno != 0) {
+			perror("strtol");
+			return 0;
+		}
+
+		return 1;
+	}
+
+	return 0;
+}
+
+void
+usage()
+{
+	fprintf(stderr, "date [-u][-d datetime] [+format]\n");
+}
 
 int
 main(int argc, char *argv[])
@@ -22,23 +47,37 @@ main(int argc, char *argv[])
 
 	setlocale(LC_ALL, "");
 
-	while((c = getopt(argc, argv, ":u")) != -1)
+	now = time(NULL);
+	if(now == (time_t)-1)
+	{
+		perror("time");
+		exit(EXIT_FAILURE);
+	}
+
+	while((c = getopt(argc, argv, ":d:u")) != -1)
 	{
 		switch(c)
 		{
+		case 'd': /* Custom datetime */
+			if(!custom_datetime(&now, optarg))
+			{
+				return 1;
+			}
+			break;
 		case 'u': /* UTC timezone */
 			uflag++;
 			break;
+		case ':':
+			fprintf(stderr, "Error: Missing operand for option: '-%c'\n", optopt);
+			usage();
+			return 1;
+		case '?':
+			fprintf(stderr, "Error: Unrecognised option: '-%c'\n", optopt);
+			usage();
+			return 1;
 		}
 	}
 
-	now = time(NULL);
-	if(now == (time_t)-1)
-	{
-		perror("time");
-		exit(EXIT_FAILURE);
-	}
-
 	if(uflag)
 	{
 		tm = gmtime(&now);
diff --git a/test-bin/date b/test-bin/date
@@ -38,16 +38,26 @@ utc_body() {
 	atf_check -o "match:^[0-9]+$" ../bin/date -u '+%s'
 }
 
+atf_test_case timestamp
+timestamp_body() {
+	atf_check -o "inline:1970-01-01T00:00:00\n" ../bin/date -u -d @0 '+%FT%T'
+	atf_check -o "inline:1970-01-01T00:01:09\n" ../bin/date -u -d @69 '+%FT%T'
+	atf_check -o "inline:1969-12-31T23:58:51\n" ../bin/date -u -d @-69 '+%FT%T'
+}
+
 atf_init_test_cases() {
 	cd "$(atf_get_srcdir)" || exit 1
 
 	. ../test_functions.sh
 
 	atf_add_test_case noargs
-	atf_add_test_case epoch
-	atf_add_test_case rfc3339
 	atf_add_test_case empty
-	atf_add_test_case utc
 	atf_add_test_case echolike
 	atf_add_test_case devfull
+
+	atf_add_test_case epoch
+	atf_add_test_case rfc3339
+	atf_add_test_case utc
+
+	atf_add_test_case timestamp
 }