90 lines
2.6 KiB
Nim
90 lines
2.6 KiB
Nim
import strformat
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import parseopt
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import osproc
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import posix
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import linux
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import os
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# should be in the linux module but seems to be missing
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const CLONE_NEWUSER = 0x10000000'i32
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# c bindings
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proc unshare(flag: cint): cint {.importc, header: "<sched.h>"}
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proc mount(source: cstring, target: cstring, filesystemtype: cstring,
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mountflags: culong, data: pointer): cint {.importc, header:"<sys/mount.h>"}
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const
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GID_MAP = "/proc/self/gid_map"
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UID_MAP = "/proc/self/uid_map"
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proc virtiofsd(paths: seq[string]): Pid =
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let uid = getuid()
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let gid = getgid()
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let pid = fork()
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if pid < 0:
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raise newException(OSError, "Fork failed")
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if pid > 0:
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# we are the parent
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return pid
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# create new mount namespace
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if unshare(CLONE_NEWUSER or CLONE_NEWNS) != 0:
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raise newException(OSError, "Unshare failed")
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# map our uid to root
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writeFile(UID_MAP, &"0 {uid} 1")
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writeFile(GID_MAP, &"0 {gid} 1")
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# create a tmpfs in /var/run so virtiofsd can write there
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if mount(cstring("tmpfs"), cstring("/var/run"), cstring("tmpfs"), 0, cstring("")) != 0:
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raise newException(OSError, "Mount failed")
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# start a virtiofsd process for each mount
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var procs {.threadvar.}: seq[Process]
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for i, path in paths:
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procs.add(startProcess(
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command = "/usr/lib/qemu/virtiofsd",
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args = @[&"--socket-path=/tmp/mount.{i}.sock", "-o", &"source={path}"],
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options = {poParentStreams}
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))
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onSignal(SIGTERM):
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for process in procs:
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terminate(process)
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quit(0)
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for process in procs:
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discard waitForExit(process)
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proc qemu*(args: OptParser) =
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let childPid = virtiofsd(@["/tmp", "/home"])
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let qemu = startProcess(
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command = "qemu-system-x86_64",
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options = {poParentStreams, poUsePath},
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args = @[
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"-enable-kvm", "-cpu", "host", "-m", "512m", "-smp", "2",
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"-kernel", "/home/martin/code/qemu/build-image/image/vmlinuz-linux",
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"-append", "earlyprintk=ttyS0 console=ttyS0 root=/dev/vda rw quiet",
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"-initrd" , "/home/martin/code/qemu/build-image/image/initramfs-linux-custom.img",
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"-m", "4G", "-object", "memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on", "-numa", "node,memdev=mem",
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"-device", "virtio-rng-pci",
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"-bios", "/usr/share/qemu/qboot.rom",
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"-drive", "if=virtio,file=/home/martin/code/qemu/build-image/image/image.qcow2",
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"-netdev", "user,id=net0,hostfwd=tcp::2222-:22",
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"-device", "virtio-net-pci,netdev=net0",
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"-nodefaults", "-no-user-config", "-nographic",
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"-serial", "stdio"
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]
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)
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discard waitForExit(qemu)
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#discard kill(childPid, SIGTERM)
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#discard waitPid(childPid,cast[var cint](nil),0)
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