Introduce an alternative way of running QEMU

tools/labs/.gitignore

@@ -6,5 +6,7 @@ rootfs.img
 disk1.img
 disk2.img
 /*core-image-*.ext4
+/*core-image-*.bz2
 .modinst
 /out/
+/rootfs

tools/labs/qemu/Makefile

@@ -40,6 +40,7 @@ TEMPDIR := $(shell mktemp -u)
 $(KCONFIG): qemu/kernel_config.x86
 	cp $^ $@
 	$(MAKE) -C $(KDIR) olddefconfig
+	$(MAKE) -C $(KDIR) mod2yesconfig
 
 zImage: $(ZIMAGE)
 
@@ -94,4 +95,41 @@ clean::
 	-rm -f disk1.img disk2.img
 	-rm -f pipe1.in pipe1.out pipe2.in pipe2.out
 
-.PHONY: boot gdb clean tap0 tap1
+# Run with one of the following:
+#     make -j$(nproc) console
+#     make -j$(nproc) gui
+
+# Attach debugger with
+#     make gdb
+
+# Stop with
+#     sync # make sure all filesystem changes are propagated
+#     CTRL-A X # kill qemu, faster and more reliable than poweroff etc.
+
+# Compile in skel directories with something like:
+#     alias kmake='make -C "$HOME/src/linux/" M="$(pwd)"'
+#     kmake
+
+YOCTO_ROOTFS = core-image-minimal-qemu$(ARCH).tar.bz2
+
+console: $(ZIMAGE) rootfs
+	MODE=console qemu/run-qemu.sh
+
+gui:
+	MODE=gui qemu/run-qemu.sh
+
+rootfs: $(YOCTO_ROOTFS)
+	mkdir -p rootfs
+	tar -xf core-image-minimal-qemux86.tar.bz2 -C rootfs
+	sed -i 's@/sbin/getty@& -n -l "/sbin/rootlogin"@' rootfs/bin/start_getty
+	printf '%s\n' '#!/bin/sh' '/bin/login -f root' > rootfs/sbin/rootlogin
+	chmod +x rootfs/sbin/rootlogin
+	mkdir -p rootfs/home/root/skels
+	echo "//10.0.2.2/skels /home/root/skels cifs port=4450,guest,user=dummy 0 0" >> rootfs/etc/fstab
+
+$(YOCTO_ROOTFS):
+	wget $(YOCTO_URL)/$(YOCTO_ROOTFS)
+
+
+
+.PHONY: console gui boot gdb clean tap0 tap1

tools/labs/qemu/kernel_config.x86

@@ -32,7 +32,7 @@ CONFIG_DEVTMPFS=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_VIRTIO_BLK=y
 CONFIG_NETDEVICES=y
-CONFIG_NETCONSOLE=m
+CONFIG_NETCONSOLE=y
 CONFIG_VIRTIO_NET=y
 CONFIG_VIRTIO_CONSOLE=y
 # CONFIG_HW_RANDOM is not set
@@ -97,3 +97,18 @@ CONFIG_UPROBE_EVENTS=y
 CONFIG_LOCKDEP=y
 # kernel lock tracing:
 CONFIG_LOCK_STAT=y
+
+# for qemu serial console ttyS0:
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+
+# for qemu default netdev:
+CONFIG_E1000=y
+
+# for CIFS/SMB/samba rootfs and share
+CONFIG_IP_PNP=y
+CONFIG_IP_PNP_DHCP=y
+CONFIG_CIFS=y
+CONFIG_CIFS_XATTR=y
+CONFIG_CIFS_POSIX=y
+CONFIG_CIFS_ROOT=y

tools/labs/qemu/run-qemu.sh

@@ -0,0 +1,114 @@
+#!/bin/bash
+
+die() { echo "$0: error: $@" >&2; exit 1; }
+
+script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" > /dev/null && pwd)"
+
+base_dir=${ROOT:-"$(readlink -f "$script_dir/..")"}
+arch=${ARCH:-"x86"}
+kernel=${ZIMAGE:-"$(readlink -f "$base_dir/../../arch/$arch/boot/bzImage")"}
+rootfs=${ROOTFS:-"$(readlink -f "$base_dir/rootfs")"}
+skels=${SKELS:-"$(readlink -f "$base_dir/skels")"}
+
+mode="${MODE:-console}"
+case "$mode" in
+    console)
+	    qemu_display="-nographic"
+	    linux_console="console=ttyS0"
+	    ;;
+    gui)
+	    # QEMU_DISPLAY = sdl, gtk, ...
+	    qemu_display="-display ${QEMU_DISPLAY:-"sdl"}"
+	    linux_console=""
+	    ;;
+    *) echo "unknown mode '$MODE'" >&2; exit 1 ;;
+esac
+
+case "$arch" in
+    x86) qemu_arch=i386 ;;
+    arm) qemu_arch=arm ;;
+    *) echo "unknown architecture '$arch'" >&2; exit 1 ;;
+esac
+
+smbd=${SMBD:-"smbd"}
+
+qemu=${QEMU:-"qemu-system-$qemu_arch"}
+qemu_kvm=${QEMU_KVM:-"-enable-kvm -cpu host"}
+qemu_cpus=${QEMU_CPUS:-"1"}
+qemu_mem=${QEMU_MEM:-"512"}
+qemu_display=${QEMU_DISPLAY:-"$qemu_display"}
+qemu_addopts=${QEMU_ADD_OPTS:-""}
+linux_console=${LINUX_CONSOLE:-"$linux_console"}
+linux_loglevel=${LINUX_LOGLEVEL:-"15"}
+linux_term=${LINUX_TERM:-"TERM=xterm"}
+linux_addcmdline=${LINUX_ADD_CMDLINE:-""}
+
+linux_cmdline=${LINUX_CMDLINE:-"root=/dev/cifs rw ip=dhcp cifsroot=//10.0.2.2/rootfs,port=4450,guest,user=dummy $linux_console loglevel=$linux_loglevel $linux_term $linux_addcmdline"}
+
+tmp_dir=$(mktemp -d)
+user=$(id -un)
+
+cat << EOF > "$tmp_dir/smbd.conf"
+[global]
+    interfaces = 127.0.0.1
+    smb ports = 4450
+    private dir = $tmp_dir
+    bind interfaces only = yes
+    pid directory = $tmp_dir
+    lock directory = $tmp_dir
+    state directory = $tmp_dir
+    cache directory = $tmp_dir
+    ncalrpc dir = $tmp_dir/ncalrpc
+    log file = $tmp_dir/log.smbd
+    smb passwd file = $tmp_dir/smbpasswd
+    security = user
+    map to guest = Bad User
+    load printers = no
+    printing = bsd
+    disable spoolss = yes
+    usershare max shares = 0
+
+    server min protocol = NT1
+    unix extensions = yes
+
+    server role = standalone server
+    public = yes
+    writeable = yes
+    #admin users = root
+    #create mask = 0777
+    #directory mask = 0777
+    force user = $user
+    force group = $user
+
+
+[rootfs]
+    path = $rootfs
+[skels]
+    path = $skels
+EOF
+
+[ -x "$(command -v "$smbd")" ] || die "samba ('$smbd') not found"
+[ -x "$(command -v "$qemu")" ] || die "qemu ('$qemu') not found"
+
+mkdir -p "$skels"
+
+"$smbd" --no-process-group -s "$tmp_dir/smbd.conf" -l "$tmp_dir" >/dev/null 2>/dev/null &
+
+"$qemu" \
+    $qemu_kvm \
+    -smp "$qemu_cpus" -m "$qemu_mem" \
+    -no-reboot \
+    -kernel "$kernel" \
+    -append "$linux_cmdline" \
+    -gdb tcp::1234 \
+    $qemu_display \
+    $qemu_addopts
+
+# This seems to reset to the mode the terminal was prior to launching QEMU
+# Inspired by
+# https://github.com/landley/toybox/blob/990e0e7a40e4509c7987a190febe5d867f412af6/toys/other/reset.c#L26-L28
+# man 4 console_codes, ESC [ ? 7 h
+printf '\e[?7h'
+
+pkill -F "$tmp_dir/smbd.pid"
+rm -rf "$tmp_dir"