Merge pull request #326 from nanonyme/sudo-helper

Add a wrapper for commmands needing sudo that checks if you are euid 0

lib/tmpdir.py

@@ -12,7 +12,7 @@
 import os
 import shutil
 
-from lib.utils import mount, umount, create_disk, run
+from lib.utils import mount, umount, create_disk, run_as_root
 
 class TmpType(enum.Enum):
     """Different types of tmpdirs we can have"""
@@ -45,7 +45,7 @@ def __del__(self):
         if not self.preserve:
             for disk in self._disks.values():
                 print(f"Detaching {disk}")
-                run("sudo", "losetup", "-d", disk)
+                run_as_root("losetup", "-d", disk)
 
             if self._type == TmpType.TMPFS:
                 print(f"Unmounting tmpdir from {self.path}")
@@ -75,7 +75,7 @@ def add_disk(self, name, size="16G", filesystem="ext4"):
         self._disks[name] = create_disk(disk_path, "msdos", filesystem, size)
         self._disk_filesystems[name] = filesystem
         # Allow executing user to access it
-        run("sudo", "chown", getpass.getuser(), self._disks[name])
+        run_as_root("chown", getpass.getuser(), self._disks[name])
 
     def mount_disk(self, name, mountpoint=None):
         """Mount the disk"""
@@ -85,7 +85,7 @@ def mount_disk(self, name, mountpoint=None):
         os.mkdir(mountpoint)
         mount(self._disks[name] + "p1", mountpoint, self._disk_filesystems[name])
         # Allow executing user to access it
-        run("sudo", "chown", getpass.getuser(), mountpoint)
+        run_as_root("chown", getpass.getuser(), mountpoint)
         self._mountpoints[name] = mountpoint
         return mountpoint
 

lib/utils.py

@@ -25,27 +25,34 @@ def run(*args, **kwargs):
         print("Bootstrapping failed")
         sys.exit(1)
 
+def run_as_root(*args, **kwargs):
+    """A helper for run that invokes sudo when unprivileged"""
+    if os.geteuid() != 0:
+        run("sudo", *args, **kwargs)
+    else:
+        run(*args, **kwargs)
+
 def create_disk(image, disk_type, fs_type, size):
     """Create a disk image, with a filesystem on it"""
     run('truncate', '-s', size, image)
     # First find the device we will use, then actually use it
-    loop_dev = run('sudo', 'losetup', '-f', capture_output=True).stdout.decode().strip()
-    run('sudo', 'losetup', '-P', loop_dev, image)
+    loop_dev = run_as_root('losetup', '-f', capture_output=True).stdout.decode().strip()
+    run_as_root('losetup', '-P', loop_dev, image)
     # Create the partition
     if disk_type != "none":
-        run('sudo', 'parted', '--script', image, 'mklabel', disk_type, 'mkpart',
+        run_as_root('parted', '--script', image, 'mklabel', disk_type, 'mkpart',
                 'primary', 'ext4', '0%', '100%')
-        run('sudo', 'partprobe', loop_dev)
-        run('sudo', 'mkfs.' + fs_type, loop_dev + "p1")
+        run_as_root('partprobe', loop_dev)
+        run_as_root('mkfs.' + fs_type, loop_dev + "p1")
     return loop_dev
 
 def mount(source, target, fs_type, options='', **kwargs):
     """Mount filesystem"""
-    run('sudo', 'mount', source, target, '-t', fs_type, '-o', options, **kwargs)
+    run_as_root('mount', source, target, '-t', fs_type, '-o', options, **kwargs)
 
 def umount(target, **kwargs):
     """Unmount filesystem"""
-    run('sudo', 'umount', '--recursive', target, **kwargs)
+    run_as_root('umount', '--recursive', target, **kwargs)
 
 def copytree(src, dst, ignore=shutil.ignore_patterns('*.git*')):
     """Copy directory tree into another directory"""

rootfs.py

@@ -19,7 +19,7 @@
 
 from sysa import SysA
 from sysc import SysC
-from lib.utils import run
+from lib.utils import run, run_as_root
 from lib.sysgeneral import stage0_arch_map
 from lib.tmpdir import Tmpdir
 
@@ -168,15 +168,15 @@ def bootstrap(args, system_a, system_c, tmpdir):
 import shutil
 print(shutil.which('chroot'))
 """
-        chroot_binary = run('sudo', 'python3', '-c', find_chroot,
-                            capture_output=True).stdout.decode().strip()
+        chroot_binary = run_as_root('python3', '-c', find_chroot,
+                                    capture_output=True).stdout.decode().strip()
 
         system_c.prepare(create_disk_image=False)
         system_a.prepare(create_initramfs=False)
 
         arch = stage0_arch_map.get(args.arch, args.arch)
         init = os.path.join(os.sep, 'bootstrap-seeds', 'POSIX', arch, 'kaem-optional-seed')
-        run('sudo', 'env', '-i', 'PATH=/bin', chroot_binary, system_a.tmp_dir, init)
+        run_as_root('env', '-i', 'PATH=/bin', chroot_binary, system_a.tmp_dir, init)
 
     elif args.bwrap:
         if not args.internal_ci or args.internal_ci == "pass1":