From 917571996614acbae61453ea7e2eadc0977b24e5 Mon Sep 17 00:00:00 2001
From: trasz <trasz@FreeBSD.org>
Date: Thu, 7 Nov 2019 18:15:24 +0000
Subject: [PATCH] Extend the linux rc script to mount the neccessary file
 systems, set ELF fallback brand, and load pty(4).

Reviewed by:	emaste (earlier version)
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21874
---
 libexec/rc/rc.d/linux | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/libexec/rc/rc.d/linux b/libexec/rc/rc.d/linux
index dab2f8d461d6..7cce3100a4c6 100755
--- a/libexec/rc/rc.d/linux
+++ b/libexec/rc/rc.d/linux
@@ -17,7 +17,7 @@ stop_cmd=":"
 
 linux_start()
 {
-	local _tmpdir
+	local _emul_path _tmpdir
 
 	load_kld -e 'linux(aout|elf)' linux
 	case `sysctl -n hw.machine_arch` in
@@ -33,6 +33,25 @@ linux_start()
 		fi
 		rm -rf ${_tmpdir}
 	fi
+
+	# Linux uses the pre-pts(4) tty naming scheme.
+	load_kld pty
+
+	# Handle unbranded ELF executables by defaulting to ELFOSABI_LINUX.
+	if [ `sysctl -ni kern.elf64.fallback_brand` -eq "-1" ]; then
+		sysctl kern.elf64.fallback_brand=3 > /dev/null
+	fi
+
+	if [ `sysctl -ni kern.elf32.fallback_brand` -eq "-1" ]; then
+		sysctl kern.elf32.fallback_brand=3 > /dev/null
+	fi
+
+	_emul_path="/compat/linux"
+	mount -o nocover -t linprocfs linprocfs "${_emul_path}/proc"
+	mount -o nocover -t linsysfs linsysfs "${_emul_path}/sys"
+	mount -o nocover -t devfs devfs "${_emul_path}/dev"
+	mount -o nocover -t fdescfs fdescfs "${_emul_path}/dev/fd"
+	mount -o nocover,mode=1777 -t tmpfs tmpfs "${_emul_path}/dev/shm"
 }
 
 load_rc_config $name