bin/sleep: add support for units other than seconds

The coreutils version of this command accepts a unit designation of s,
m, h, or d (for seconds, minutes, hours, days) immediately following
the number of (fractional) units to delay.

The submitted patch has been modified in one detail: the test meant to
detect the presence of the unit modified was not specific (!= 1) and
would have accepted a non-numeric initial element or extra characters
following the union. The committed version accepts only the number
immediately followed by one of the defined unit designators and no
further characters.

PR:		264162
MFC after:	1 week

2 files changed, 25 insertions, 5 deletions

diff --git a/bin/sleep/sleep.1 b/bin/sleep/sleep.1
index 924bc732a0d0..3ce82936a0e7 100644
--- a/bin/sleep/sleep.1
+++ b/bin/sleep/sleep.1
@@ -40,13 +40,21 @@
 .Nd suspend execution for an interval of time
 .Sh SYNOPSIS
 .Nm
-.Ar seconds
+.Ar number[unit]
 .Sh DESCRIPTION
 The
 .Nm
 command
 suspends execution for a minimum of
-.Ar seconds .
+.Ar number
+seconds (the default, or unit
+.Ar s ) ,
+or minutes (unit
+.Ar m ) ,
+hours (unit
+.Ar h ) ,
+or days (unit
+.Ar d ) .
 .Pp
 If the
 .Nm
diff --git a/bin/sleep/sleep.c b/bin/sleep/sleep.c
index b4b54a336100..8f383e43c479 100644
--- a/bin/sleep/sleep.c
+++ b/bin/sleep/sleep.c
@@ -66,6 +66,7 @@ main(int argc, char *argv[])
 	struct timespec time_to_sleep;
 	double d;
 	time_t original;
+	char unit;
 	char buf[2];
 
 	if (caph_limit_stdio() < 0 || caph_enter() < 0)
@@ -74,8 +75,17 @@ main(int argc, char *argv[])
 	if (argc != 2)
 		usage();
 
-	if (sscanf(argv[1], "%lf%1s", &d, buf) != 1)
-		usage();
+	if (sscanf(argv[1], "%lf%c%1s", &d, &unit, buf) == 2)
+		switch(unit) {
+			case 'd': d *= 24;
+			case 'h': d *= 60;
+			case 'm': d *= 60;
+			case 's': break;
+			default:  usage();
+		}
+	else
+		if (sscanf(argv[1], "%lf%1s", &d, buf) != 1)
+			usage();
 	if (d > INT_MAX)
 		usage();
 	if (d <= 0)
@@ -106,6 +116,8 @@ static void
 usage(void)
 {
 
-	fprintf(stderr, "usage: sleep seconds\n");
+	fprintf(stderr, "usage: sleep number[unit]\n");
+	fprintf(stderr, "Unit can be 's' (seconds, the default), "
+			"m (minutes), h (hours), or d (days).\n");
 	exit(1);
 }