From e70bf8f4f487b56276db09390949cd865bfca43e Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Mon, 13 Nov 2023 21:00:03 +0800
Subject: hostreqs: Bump Coreutils minimal version to 8.1 and check for nproc

We'll use nproc for setting MAKEFLAGS and TESTSUITEFLAGS.  And if nproc
is not available, we'll end up with "MAKEFLAGS=-j" which is very
dangerous because it allows make to spawn infinite number of jobs.
Check it early.

The nproc program is added in Coreutils 8.1 so we need to bump the
minimal version.
---
 chapter02/hostreqs.xml | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/chapter02/hostreqs.xml b/chapter02/hostreqs.xml
index 69533b9c7..63dcd943f 100644
--- a/chapter02/hostreqs.xml
+++ b/chapter02/hostreqs.xml
@@ -54,8 +54,9 @@
       should be a link to bison or a small script that executes bison)</para>
     </listitem>
 
+    <!-- In Coreutils-8.1 the nproc program is added.  -->
     <listitem>
-      <para><emphasis role="strong">Coreutils-7.0</emphasis></para>
+      <para><emphasis role="strong">Coreutils-8.1</emphasis></para>
     </listitem>
 
     <listitem>
@@ -218,8 +219,8 @@ ver_kernel()
    fi
 }
 
-# Coreutils first because-sort needs Coreutils >= 7.0
-ver_check Coreutils      sort     7.0 || bail "--version-sort unsupported"
+# Coreutils first because --version-sort needs Coreutils >= 7.0
+ver_check Coreutils      sort     8.1 || bail "Coreutils too old, stop"
 ver_check Bash           bash     3.2
 ver_check Binutils       ld       2.13.1
 ver_check Bison          bison    2.7
@@ -259,7 +260,13 @@ echo "Compiler check:"
 if printf "int main(){}" | g++ -x c++ -
 then echo "OK:    g++ works";
 else echo "ERROR: g++ does NOT work"; fi
-rm -f a.out</literal>
+rm -f a.out
+
+if [ "$(nproc)" = "" ]; then
+   echo "ERROR: nproc is not available or it produces empty output"
+else
+   echo "OK: nproc reports $(nproc) logical cores are available"
+fi</literal>
 EOF
 
 bash version-check.sh</userinput></screen>
-- 
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