[fixinc] Allow CONFIG_SHELL to override build-time shell in mkheaders

[fixinc] Allow CONFIG_SHELL to override build-time shell in mkheaders

[Alexandre Oliva]

mkheaders.in uses substitutions of @SHELL@ to run fixinc.sh and
mkinstalldirs.  Problem is, SHELL comes from CONFIG_SHELL for the
build system, and it needs not match whatever is available at an
unrelated host system after installation, when mkheaders is supposed
to be run.

I considered ditching the hardcoding altogether, but decided to retain
it, but allowing CONFIG_SHELL and SHELL to override it, if any of them
can successfully run mkinstalldirs, and if those and the substituted
@SHELL@ fail, fallback to /bin/sh and to plain execution of the
script, which appears to enable at least one shell on a system that
doesn't typicall have a shell to recognize a script by #!/bin/sh and
reinvoke itself to run it.

If all of these fail, we fail, but only after telling the user to
retry after setting CONFIG_SHELL, that fixincl itself also uses.

Tested with a x86_64-linux-gnu native, and on various combinations of
build, host and targets, including cross and canadian crosses involving
host systems that don't have a built-in Bourne Shell.  I'm going ahead
and checking it in as part of the build machinery, though I acknowledge
this might be stretching configury a bit.  Please let me know if you
have any objections to this stretching, or to the change itself.


for  fixincludes/ChangeLog

	* mkheaders.in: Don't require build-time shell on host.
---
 fixincludes/mkheaders.in |   22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/fixincludes/mkheaders.in b/fixincludes/mkheaders.in
index a293a57..4109dc6 100644
--- a/fixincludes/mkheaders.in
+++ b/fixincludes/mkheaders.in
@@ -77,11 +77,29 @@ libexecsubdir=${libexecdir}/gcc/${target_noncanonical}/${version}
 itoolsdir=${libexecsubdir}/install-tools
 itoolsdatadir=${libsubdir}/install-tools
 incdir=${libsubdir}/include-fixed
-mkinstalldirs="@SHELL@ ${itoolsdir}/mkinstalldirs"
+mkinstalldirs="${itoolsdir}/mkinstalldirs"
 
 cd ${itoolsdir}
 rm -rf ${incdir}/*
 
+for shell in $CONFIG_SHELL $SHELL @SHELL@ /bin/sh ""; do
+  if { test -x $shell || test -x $shell.exe; } \
+  && $shell $mkinstalldirs > /dev/null 2>&1; then
+    mkinstalldirs="$shell $mkinstalldirs"
+    break
+  elif test x$shell = x; then
+    if $mkinstalldirs > /dev/null 2>&1; then
+      break
+    elif test ! -f $mkinstalldirs; then
+      echo mkheaders: could not find $mkinstalldirs >&2
+      exit 1
+    else
+      echo mkheaders: please rerun with CONFIG_SHELL set to a working Bourne shell >&2
+      exit 1
+    fi
+  fi
+done
+
 for ml in `cat ${itoolsdatadir}/fixinc_list`; do
   sysroot_headers_suffix=`echo ${ml} | sed -e 's/;.*$//'`
   multi_dir=`echo ${ml} | sed -e 's/^[^;]*;//'`
@@ -91,7 +109,7 @@ for ml in `cat ${itoolsdatadir}/fixinc_list`; do
   if [ x${STMP_FIXINC} != x ] ; then
 	TARGET_MACHINE="${target}" target_canonical="${target}" \
 	    MACRO_LIST="${itoolsdatadir}/macro_list" \
-	    @SHELL@ ./fixinc.sh ${subincdir} \
+	    $shell ./fixinc.sh ${subincdir} \
 	    ${isysroot}${SYSTEM_HEADER_DIR} ${OTHER_FIXINCLUDES_DIRS}
 	rm -f ${subincdir}/syslimits.h
 	if [ -f ${subincdir}/limits.h ]; then

-- 
Alexandre Oliva, freedom fighter    he/him    https://FSFLA.org/blogs/lxo/
Free Software Evangelist              Stallman was right, but he's left :(
GNU Toolchain Engineer   The darkest places in hell are reserved for those
who maintain their neutrality in times of moral crisis. -- Dante Alighieri

Re: [fixinc] Allow CONFIG_SHELL to override build-time shell in mkheaders

[Jeff Law]

On Thu, 2020-02-20 at 22:17 -0300, Alexandre Oliva wrote:
> mkheaders.in uses substitutions of @SHELL@ to run fixinc.sh and
> mkinstalldirs.  Problem is, SHELL comes from CONFIG_SHELL for the
> build system, and it needs not match whatever is available at an
> unrelated host system after installation, when mkheaders is supposed
> to be run.
> 
> I considered ditching the hardcoding altogether, but decided to retain
> it, but allowing CONFIG_SHELL and SHELL to override it, if any of them
> can successfully run mkinstalldirs, and if those and the substituted
> @SHELL@ fail, fallback to /bin/sh and to plain execution of the
> script, which appears to enable at least one shell on a system that
> doesn't typicall have a shell to recognize a script by #!/bin/sh and
> reinvoke itself to run it.
> 
> If all of these fail, we fail, but only after telling the user to
> retry after setting CONFIG_SHELL, that fixincl itself also uses.
> 
> Tested with a x86_64-linux-gnu native, and on various combinations of
> build, host and targets, including cross and canadian crosses involving
> host systems that don't have a built-in Bourne Shell.  I'm going ahead
> and checking it in as part of the build machinery, though I acknowledge
> this might be stretching configury a bit.  Please let me know if you
> have any objections to this stretching, or to the change itself.
> 
> 
> for  fixincludes/ChangeLog
> 
> 	* mkheaders.in: Don't require build-time shell on host.
OK
jeff
>