1 files changed, 131 insertions, 0 deletions
diff --git a/pkgs/os-specific/linux/chromium-os/update.py b/pkgs/os-specific/linux/chromium-os/update.py
new file mode 100755
index 00000000000..5852d4a3069
--- /dev/null
+++ b/pkgs/os-specific/linux/chromium-os/update.py
@@ -0,0 +1,131 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i python -p "python3.withPackages (ps: with ps; [ lxml ])"
+
+import base64
+import json
+import subprocess
+from codecs import iterdecode
+from os import scandir
+from os.path import dirname, splitext
+from lxml import etree
+from lxml.etree import HTMLParser
+from re import MULTILINE, fullmatch, match, search
+from urllib.request import urlopen
+
+# ChromiumOS components used in Nixpkgs
+component_paths = [
+    'src/aosp/external/minijail',
+    'src/platform/crosvm',
+    'src/platform/minigbm',
+    'src/platform2',
+    'src/third_party/adhd',
+    'src/third_party/chromiumos-overlay',
+    'src/third_party/kernel/v5.4',
+    'src/third_party/libqmi',
+    'src/third_party/modemmanager-next',
+    'src/third_party/modp_b64',
+    'src/third_party/rust-vmm/vhost',
+]
+
+git_root = 'https://chromium.googlesource.com/'
+manifest_versions = f'{git_root}chromiumos/manifest-versions'
+buildspecs_url = f'{manifest_versions}/+/refs/heads/master/full/buildspecs/'
+
+# CrOS version numbers look like this:
+# [<chrome-major-version>.]<tip-build>.<branch-build>.<branch-branch-build>
+#
+# As far as I can tell, branches are where internal Google
+# modifications are added to turn Chromium OS into Chrome OS, and
+# branch branches are used for fixes for specific devices.  So for
+# Chromium OS they will always be 0.  This is a best guess, and is not
+# documented.
+with urlopen('https://cros-updates-serving.appspot.com/') as resp:
+    document = etree.parse(resp, HTMLParser())
+
+    # bgcolor="lightgreen" is set on the most up-to-date version for
+    # each channel, so find a lightgreen cell in the "Stable" column.
+    (platform_version, chrome_version) = document.xpath("""
+        (//table[@id="cros-updates"]/tr/td[1 + count(
+            //table[@id="cros-updates"]/thead/tr[1]/th[text() = "Stable"]
+            /preceding-sibling::*)
+        ][@bgcolor="lightgreen"])[1]/text()
+    """)
+
+chrome_major_version = match(r'\d+', chrome_version)[0]
+chromeos_tip_build = match(r'\d+', platform_version)[0]
+
+# Find the most recent buildspec for the stable Chrome version and
+# Chromium OS build number.  Its branch build and branch branch build
+# numbers will (almost?) certainly be 0.  It will then end with an rc
+# number -- presumably these are release candidates, one of which
+# becomes the final release.  Presumably the one with the highest rc
+# number.
+with urlopen(f'{buildspecs_url}{chrome_major_version}/?format=TEXT') as resp:
+    listing = base64.decodebytes(resp.read()).decode('utf-8')
+    buildspecs = [(line.split('\t', 1)[1]) for line in listing.splitlines()]
+    buildspecs = [s for s in buildspecs if s.startswith(chromeos_tip_build)]
+    buildspecs.sort(reverse=True)
+    buildspec = splitext(buildspecs[0])[0]
+
+components = {}
+
+# Read the buildspec, and extract the git revisions for each component.
+with urlopen(f'{buildspecs_url}{chrome_major_version}/{buildspec}.xml?format=TEXT') as resp:
+    xml = base64.decodebytes(resp.read())
+    root = etree.fromstring(xml)
+
+    default_remote = root.find('default').get('remote')
+    remotes = {}
+    for remote in root.findall('remote'):
+        remotes[remote.get('name')] = remote.get('fetch')
+
+    for project in root.findall('project'):
+        name = project.get('name')
+        path = project.get('path')
+        remote_name = project.get('remote') or default_remote
+        remote = remotes[remote_name]
+
+        components[path] = {
+            'revision': project.get('revision'),
+            'url': f'{remote}/{name}',
+        }
+
+# Initialize the data that will be output from this script.  Leave the
+# rc number in buildspec so nobody else is subject to the same level
+# of confusion I have been.
+data = {'version': f'{chrome_major_version}.{buildspec}', 'components': {}}
+
+paths = {}
+
+# Fill in the 'components' dictionary with the output from
+# nix-prefetch-git, which can be passed straight to fetchGit when
+# imported by Nix.
+for path in component_paths:
+    name = path.split('/')[-1]
+    url = components[path]['url']
+    rev = components[path]['revision']
+    tarball = f'{url}/+archive/{rev}.tar.gz'
+    output = subprocess.check_output(['nix-prefetch-url', '--print-path', '--unpack', '--name', name, tarball])
+    (sha256, store_path) = output.decode('utf-8').splitlines()
+    paths[path] = store_path
+    data['components'][path] = {
+        'name': name,
+        'url': url,
+        'rev': rev,
+        'sha256': sha256,
+    }
+
+# Get the version number of the kernel.
+kernel = paths['src/third_party/kernel/v5.4']
+makefile = open(f'{kernel}/Makefile').read()
+version = search(r'^VERSION = (.+)$', makefile, MULTILINE)[1]
+patchlevel = search(r'^PATCHLEVEL = (.*?)$', makefile, MULTILINE)[1]
+sublevel = search(r'^SUBLEVEL = (.*?)$', makefile, MULTILINE)[1]
+extra = search(r'^EXTRAVERSION =[ \t]*(.*?)$', makefile, MULTILINE)[1]
+full_ver = '.'.join(filter(None, [version, patchlevel, sublevel])) + extra
+data['components']['src/third_party/kernel/v5.4']['version'] = full_ver
+
+# Finally, write the output.
+with open(dirname(__file__) + '/upstream-info.json', 'w') as out:
+    json.dump(data, out, indent=2)
+    out.write('\n')