utils: Add cmdline_shebang_wrapper util.

Useful to work around shebang relocation issues, where
shebangs are too long or have arguments in them, thus preventing them
from using the /usr/bin/env shebang.

Signed-off-by: Paulo Neves <ptsneves@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

4 files changed, 68 insertions, 0 deletions

diff --git a/meta-selftest/recipes-test/wrapper/cmdline-shebang-wrapper-test.bb b/meta-selftest/recipes-test/wrapper/cmdline-shebang-wrapper-test.bb
new file mode 100644
index 0000000000..c4126a41fc
--- /dev/null
+++ b/meta-selftest/recipes-test/wrapper/cmdline-shebang-wrapper-test.bb
@@ -0,0 +1,21 @@
+SUMMARY = "Check that create_cmdline_shebang works"
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
+INHIBIT_DEFAULT_DEPS = "1"
+
+SRC_URI += "file://test.awk"
+
+EXCLUDE_FROM_WORLD = "1"
+do_install() {
+    install -d ${D}${bindir}
+    install -m 0755 ${WORKDIR}/test.awk ${D}${bindir}/test
+    sed -i -e 's|@AWK_BIN@|${bindir}/awk|g' ${D}${bindir}/test
+    create_cmdline_shebang_wrapper ${D}${bindir}/test
+    if [ $(${D}${bindir}/test) != "Don't Panic!" ]; then
+        bbfatal "Wrapper is broken"
+    else
+        bbnote "Wrapper is good"
+    fi
+}
+
+BBCLASSEXTEND = "native"
diff --git a/meta-selftest/recipes-test/wrapper/files/test.awk b/meta-selftest/recipes-test/wrapper/files/test.awk
new file mode 100644
index 0000000000..91429197b1
--- /dev/null
+++ b/meta-selftest/recipes-test/wrapper/files/test.awk
@@ -0,0 +1,2 @@
+#! @AWK_BIN@ -f
+BEGIN { print "Don't Panic!" }
diff --git a/meta/classes/utils.bbclass b/meta/classes/utils.bbclass
index b4eb3d38ab..b617632d9f 100644
--- a/meta/classes/utils.bbclass
+++ b/meta/classes/utils.bbclass
@@ -184,6 +184,40 @@ END
 	chmod +x $cmd
 }
 
+create_cmdline_shebang_wrapper () {
+	# Create a wrapper script where commandline options are needed
+	#
+	# These are useful to work around shebang relocation issues, where shebangs are too
+  # long or have arguments in them, thus preventing them from using the /usr/bin/env
+	# shebang
+	#
+	# Usage: create_cmdline_wrapper FILENAME <extra-options>
+
+	cmd=$1
+	shift
+
+	echo "Generating wrapper script for $cmd"
+
+  # Strip #! and get remaining interpreter + arg
+  argument="$(basename "$(head -n1 $cmd | sed -e 's|#![ ]*||g' )")"
+  # strip the shebang from the real script as we do not want it to be usable anyway
+  tail -n +2 $cmd > $cmd.real
+	cmdname=$(basename $cmd)
+	dirname=$(dirname $cmd)
+	cmdoptions=$@
+	if [ "${base_prefix}" != "" ]; then
+		relpath=`python3 -c "import os; print(os.path.relpath('${D}${base_prefix}', '$dirname'))"`
+		cmdoptions=`echo $@ | sed -e "s:${base_prefix}:\\$realdir/$relpath:g"`
+	fi
+	cat <<END >$cmd
+#!/usr/bin/env bash
+realpath=\`readlink -fn \$0\`
+realdir=\`dirname \$realpath\`
+exec -a \$realdir/$cmdname $argument \$realdir/$cmdname.real $cmdoptions "\$@"
+END
+	chmod +x $cmd
+}
+
 create_wrapper () {
 	# Create a wrapper script where extra environment variables are needed
 	#
diff --git a/meta/lib/oeqa/selftest/cases/wrapper.py b/meta/lib/oeqa/selftest/cases/wrapper.py
new file mode 100644
index 0000000000..6de63310c0
--- /dev/null
+++ b/meta/lib/oeqa/selftest/cases/wrapper.py
@@ -0,0 +1,11 @@
+from oeqa.selftest.case import OESelftestTestCase
+from oeqa.utils.commands import bitbake
+
+class WrapperTests(OESelftestTestCase):
+    def test_shebang_wrapper(self):
+        """
+        Summary:   Build a recipe which will fail if the cmdline_shebang_wrapper function is defective.
+        Expected:  Exit status to be 0.
+        Author:    Paulo Neves <ptsneves@gmail.com>
+        """
+        res = bitbake("cmdline-shebang-wrapper-test -c install", ignore_status=False)