Assembler: no longer mount devtmpfs in the container

Move the only assembler that relied on this to use LoopClient instead.

Signed-off-by: Tom Gundersen <teg@jklm.no>

assemblers/io.weldr.qcow2

@@ -4,9 +4,11 @@ import contextlib
 import json
 import math
 import os
+import socket
 import subprocess
 import sys
 import tempfile
+import osbuild.remoteloop as remoteloop
 
 def tree_size(tree):
     size = 0
@@ -34,16 +36,17 @@ def mount_api(dest):
         yield
 
 @contextlib.contextmanager
-def loop_device(image, size, offset=0):
-    r = subprocess.run(["losetup", "--partscan", "--show", "--find", "--sizelimit", str(size), "--offset", str(offset),
-                        image], stdout=subprocess.PIPE, encoding="utf-8", check=True)
-    loop = r.stdout.strip()
+def loop_device(loop_client, image, size, offset=0):
+    fd = os.open(image, os.O_RDWR)
+    devname = loop_client.create_device(fd, offset=offset, sizelimit=size)
+    os.close(fd)
+    path = f"/dev/{devname}"
     try:
-        yield loop
+        yield path
     finally:
-        subprocess.run(["losetup", "-d", loop], check=True)
+        os.unlink(path)
 
-def main(tree, output_dir, options):
+def main(tree, output_dir, options, loop_client):
     filename = options["filename"]
     root_fs_uuid = options["root_fs_uuid"]
 
@@ -72,17 +75,20 @@ def main(tree, output_dir, options):
                         f"{int(partition_size / 1024)}k"], input="y", encoding='utf-8', check=True)
 
         # Mount the created image as a loopback device
-        with loop_device(image, partition_offset) as loop_block, \
-            loop_device(image, partition_size, partition_offset) as loop_part, \
+        with loop_device(loop_client, image, partition_offset) as loop_block, \
+            loop_device(loop_client, image, partition_size, partition_offset) as loop_part, \
             mount(loop_part, mountpoint):
             # Install grub2 into the boot sector of the image, and copy the grub2 imagise into /boot/grub2
             with mount_api(mountpoint):
-                subprocess.run(["chroot", mountpoint, "grub2-install", "--no-floppy", "--modules=part_msdos", "--target=i386-pc", loop_block],
-                               check=True)
+                subprocess.run(["chroot", mountpoint, "grub2-install", "--no-floppy",
+                                "--modules=part_msdos", "--target=i386-pc", loop_block], check=True)
 
         subprocess.run(["qemu-img", "convert", "-O", "qcow2", "-c", image, f"{output_dir}/{filename}"], check=True)
 
 if __name__ == '__main__':
     args = json.load(sys.stdin)
-    ret = main(args["tree"], args["output_dir"], args["options"])
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_PASSCRED, 1)
+    sock.connect("/run/osbuild/api/remoteloop")
+    ret = main(args["tree"], args["output_dir"], args["options"], remoteloop.LoopClient(sock))
     sys.exit(ret)

osbuild/__init__.py

@@ -228,7 +228,7 @@ class Assembler:
                 "options": self.options,
             }
 
-            binds = ["/dev:/dev"]
+            binds = []
             if output_dir:
                 os.makedirs(output_dir, exist_ok=True)
                 binds.append(f"{output_dir}:/run/osbuild/output")