Start rewrite in nim

nim/commands/help.nim

@@ -0,0 +1,16 @@
+import std/strformat
+import std/parseopt
+import os
+
+proc help*(args: OptParser) =
+  let bin = lastPathPart(getAppFilename())
+
+  echo "qsandbox - temporary sandboxes using qemu"
+  echo ""
+  echo "Usage:"
+  echo &"   {bin} run   - start sandbox and mount current working dir"
+  echo &"   {bin} list  - list running sandboxes"
+  echo &"   {bin} enter - open ssh connection to a sandbox"
+  echo &"   {bin} qemu  - start the qemu process for a new sandbox, used by run"
+
+  quit(0)

nim/commands/list.nim

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+import std/parseopt
+
+proc list*(args: OptParser) =
+  echo "list"

nim/commands/qemu.nim

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

nim/commands/run.nim

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+import std/parseopt
+
+proc run*(args: OptParser) =
+  echo "Run"

nim/commands/ssh.nim

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+import std/parseopt
+
+proc ssh*(args: OptParser) =
+  echo "ssh"