syslinux: add util/syslinux.go script.

This basically works; once it's done you can
usr GO9PIMG.

Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>

util/syslinux.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+)
+
+var (
+	setupcmds = []struct {
+		*exec.Cmd
+		in io.Reader
+	}{
+		{Cmd: exec.Command("qemu-img", "create", "-f", "qcow2", "harvey.qcow2", "3G")},
+		{Cmd: exec.Command("modprobe", "nbd", "max_part=63")},
+		{Cmd: exec.Command("qemu-nbd", "-c", "/dev/nbd0", "harvey.qcow2")},
+		{Cmd: exec.Command("dd", "conv=notrunc", "bs=440", "count=1", "if=img/syslinux-bios/mbr.bin", "of=/dev/nbd0")},
+		{Cmd: exec.Command("sfdisk", "/dev/nbd0"), in: bytes.NewBufferString(part)},
+		{Cmd: exec.Command("mkfs.ext4", "/dev/nbd0p1")},
+		{Cmd: exec.Command("mount", "/dev/nbd0p1", "disk/")},
+		{Cmd: exec.Command("extlinux", "-i", "disk/")},
+		{Cmd: exec.Command("cp", "../sys/src/9/amd64/harvey.32bit", "disk/harvey")},
+		{Cmd: exec.Command("ls", "-l", "disk")},
+	}
+	part = `label: dos
+label-id: 0xadc9f7b1
+device: /dev/nbd0
+unit: sectors
+
+/dev/nbd0p1 : start=        2048, size=     6289408, type=83, bootable
+`
+	syslinuxconfig = []byte(`# syslinux.cfg
+#TIMEOUT = Time to wait to autoboot in 1/10 secs. zero (0) disables the timeout 
+#PROMPT = one (1) displays the prompt only, zero (0) will not display the prompt
+#ONTIMEOUT = The default menu label to automatically boot at timeout (selected after timeout)
+#DISPLAY = Optional menu text if not using LABEL Entries
+
+TIMEOUT 1000
+DEFAULT vesamenu.c32
+#MENU BACKGROUND /backgroundimages/your_image_here.png
+MENU TITLE Harvey OS
+PROMPT 0
+ONTIMEOUT 1
+#DISPLAY Menu.txt
+
+#Display help text when F1 pressed on Syslinux Menu
+F1 help.txt
+
+LABEL 0
+MENU LABEL Reboot
+TEXT HELP
+Restart the computer
+ENDTEXT
+COM32 reboot.c32
+
+LABEL 1
+TEXT HELP
+Boot Harvey kernel
+ENDTEXT
+MENU LABEL Harvey OS
+KERNEL mboot.c32
+APPEND ../harvey
+
+`)
+)
+
+func detach() {
+	log.Println("Detaching")
+	if err := exec.Command("umount", "disk").Run(); err != nil {
+		log.Print(err)
+	}
+	if err := exec.Command("qemu-nbd", "-d", "/dev/nbd0").Run(); err != nil {
+		log.Print(err)
+	}
+}
+
+func main() {
+
+	if os.Getuid() != 0 {
+		log.Fatalf("You have to run me as root")
+	}
+
+	defer detach()
+
+	for _, c := range setupcmds {
+		c.Stdin, c.Stdout, c.Stderr = c.in, os.Stdout, os.Stderr
+		if err := c.Run(); err != nil {
+			log.Fatalf("%v: %v", c, err)
+		}
+	}
+
+	fi, err := ioutil.ReadDir("img/syslinux-bios/syslinux")
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := os.Mkdir("disk/syslinux", 0777); err != nil {
+		log.Print(err)
+	}
+	for _, f := range fi {
+		log.Printf("Process %v", f)
+		b, err := ioutil.ReadFile(filepath.Join("img/syslinux-bios/syslinux", f.Name()))
+		if err != nil {
+			log.Fatal(err)
+		}
+		if err := ioutil.WriteFile(filepath.Join("disk/syslinux/", f.Name()), b, 0666); err != nil {
+			log.Fatal(err)
+		}
+	}
+	if err := ioutil.WriteFile(filepath.Join("disk/syslinux/", "syslinux.cfg"), syslinuxconfig, 0666); err != nil {
+		log.Fatal(err)
+	}
+}