Re: install-sh -s on readonly file

[Paul Eggert <eggert@cs.ucla.edu>]

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Karl Berry wrote:
> -    { test -z "$stripcmd" || $doit $stripcmd "$dsttmp"; } &&
> +    { test -z "$stripcmd" || ($doit $chmodcmd u+w "$dsttmp"; $doit $stripcmd "$dsttmp") } &&

How about the attached Automake patch instead? It avoids the extra forks and 
exec. Admittedly it's longer.

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From c50db415f06d3a29780fe9650654165f6fa28bf0 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sun, 25 Aug 2019 18:51:26 -0700
Subject: [PATCH] install-sh: support -s with read-only source
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Problem reported by Karl Berry in:
https://lists.gnu.org/r/bug-gnulib/2019-08/msg00067.html
* lib/install-sh: If -s is given, create the temporary file
with $cp_umask so that ‘strip’ can write to it.
---
 lib/install-sh | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/install-sh b/lib/install-sh
index 8175c640f..1f5cdccc7 100755
--- a/lib/install-sh
+++ b/lib/install-sh
@@ -451,7 +451,16 @@ do
     trap 'ret=$?; rm -f "$dsttmp" "$rmtmp" && exit $ret' 0
 
     # Copy the file name to the temp name.
-    (umask $cp_umask && $doit_exec $cpprog "$src" "$dsttmp") &&
+    (umask $cp_umask &&
+     { test -z "$stripcmd" || {
+	 if test -z "$doit"; then
+	   : >"$dsttmp" # No need to fork-exec 'touch'.
+	 else
+	   $doit touch "$dsttmp"
+	 fi
+       }
+     } &&
+     $doit_exec $cpprog "$src" "$dsttmp") &&
 
     # and set any options; do chmod last to preserve setuid bits.
     #
-- 
2.21.0