>From 5e96377bf15f47af66348efe3cfa28302da97f0d Mon Sep 17 00:00:00 2001
From: Bernhard Voelker <address@hidden>
Date: Wed, 30 Jul 2014 09:18:57 +0200
Subject: [PATCH] sleep: support subtraction of sleep amounts

* src/sleep.c (main): Check for non-negative sleep amount for the
resulting total only instead of for each individual argument.
* tests/misc/sleep.sh: New file.
* tests/local.mk (all_tests): Add it.
* doc/coreutils.texi (sleep invocation): Add an example.
* NEWS (Improvements): Mention the change.

Discussed in http://bugs.gnu.org/7877#67
---
 NEWS                |  4 +++
 doc/coreutils.texi  |  5 ++++
 src/sleep.c         |  9 ++++--
 tests/local.mk      |  1 +
 tests/misc/sleep.sh | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 96 insertions(+), 2 deletions(-)
 create mode 100755 tests/misc/sleep.sh

diff --git a/NEWS b/NEWS
index 511e626..3760b24 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,10 @@ GNU coreutils NEWS                                    -*- outline -*-
 
 * Noteworthy changes in release ?.? (????-??-??) [?]
 
+** Improvements
+
+  sleep now supports subtraction of sleep amounts among arguments.
+
 
 * Noteworthy changes in release 8.23 (2014-07-18) [stable]
 
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 96f0781..374113f 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -16858,6 +16858,11 @@ Historical implementations of @command{sleep} have required that
 without a suffix.  However, GNU @command{sleep} accepts
 arbitrary floating point numbers.  @xref{Floating point}.
 
+The following example shows how to sleep 10 minutes less than a day:
+@example
+$ sleep -- 1d -10m
+@end example
+
 The only options are @option{--help} and @option{--version}.  @xref{Common
 options}.
 
diff --git a/src/sleep.c b/src/sleep.c
index e24c251..bd758ad 100644
--- a/src/sleep.c
+++ b/src/sleep.c
@@ -125,8 +125,6 @@ main (int argc, char **argv)
       double s;
       const char *p;
       if (! xstrtod (argv[i], &p, &s, c_strtod)
-          /* Nonnegative interval.  */
-          || ! (0 <= s)
           /* No extra chars after the number and an optional s,m,h,d char.  */
           || (*p && *(p+1))
           /* Check any suffix char and update S based on the suffix.  */
@@ -139,6 +137,13 @@ main (int argc, char **argv)
       seconds += s;
     }
 
+  /* Rule out negative and infinite-and-non-positive numbers.  */
+  if (ok && ! (0 <= seconds))
+    {
+      error (0, 0, _("invalid total sleep time %f"), seconds);
+      ok = false;
+    }
+
   if (!ok)
     usage (EXIT_FAILURE);
 
diff --git a/tests/local.mk b/tests/local.mk
index e0f1f84..2d4060c 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -318,6 +318,7 @@ all_tests =					\
   tests/misc/shred-negative.sh			\
   tests/misc/shred-passes.sh			\
   tests/misc/shred-remove.sh			\
+  tests/misc/sleep.sh				\
   tests/misc/shuf.sh				\
   tests/misc/shuf-reservoir.sh			\
   tests/misc/sort.pl				\
diff --git a/tests/misc/sleep.sh b/tests/misc/sleep.sh
new file mode 100755
index 0000000..d365536
--- /dev/null
+++ b/tests/misc/sleep.sh
@@ -0,0 +1,79 @@
+#!/bin/sh
+# Exercise sleep summing up and subtracting arguments.
+
+# Copyright (C) 2014 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ sleep
+
+# Check that 0 (Zero) is accepted.
+env sleep 0 || fail=1
+
+do_sleep ()
+{
+  t=$1    # timeout
+  exp=$2  # expected exit code
+  shift 2 || framework_failure_
+  timeout $t env sleep -- "$@"
+  test $? = $exp
+}
+
+# Check that sleep sums up the arguments.
+do_sleep .3   0 .01 || fail=1
+do_sleep .3 124 .01 2 || fail=1
+do_sleep .3 124 .09 .01 2 || fail=1
+
+# Check that subtracting works.
+do_sleep .3   0 1m -59.99s || fail=1
+do_sleep .5 124 1m -59s || fail=1
+
+# Check that subtracting works with more arguments.
+do_sleep .3   0 1d -23h -59m -59.99s || fail=1
+do_sleep .5 124 1d -23h -59m -59s || fail=1
+
+# Check that subtracting works starting with a negative number.
+do_sleep .3   0 -1d 24h .01 || fail=1
+
+inv_sleep ()
+{
+  rm -f out err err2 || framework_failure_
+
+  env sleep -- "$@" >out 2>err && fail=1
+  sed 's/\(sleep: invalid total sleep time \).*$/\1x/' \
+    < err > err2 || framework_failure_
+  compare /dev/null out || fail=1
+  compare exp err2 || fail=1
+  return $fail
+}
+
+cat <<! > exp
+sleep: invalid total sleep time x
+Try 'sleep --help' for more information.
+!
+
+# Do not allow negative ...
+inv_sleep -1                || fail=1
+inv_sleep 1m -61s           || fail=1
+inv_sleep 1d -23h -59m -61s || fail=1
+
+# ... or otherwise invalid sleep times.
+for i in -inf nan -nan ; do
+  for j in '' 1 inf -inf nan -nan ; do
+    inv_sleep $i $j || fail=1
+  done
+done
+
+Exit $fail
-- 
1.8.4.5