support downloading and unpacking GrapheneOS images

src/frontend/source.ts

@@ -388,7 +388,11 @@ async function unpackFactoryImage(factoryImagePath: string, image: DeviceImage,
     // There's a TOCTOU race (file is accessed after check), but it affects all other generated files too.
     // Fixing it for this particular case is not worth the complexity increase
   } else {
-    throw new Error(`SHA-256 mismatch for '${image.fileName}': expected ${image.sha256} got ${sha256}`)
+    if (image.skipSha256Check) {
+      console.warn(`skipping SHA-256 check for ${image.fileName}, SHA-256: ${sha256}`)
+    } else {
+      throw new Error(`SHA-256 mismatch for '${image.fileName}': expected ${image.sha256} got ${sha256}`)
+    }
   }
 
   let fd = await fs.open(factoryImagePath, 'r')
@@ -400,9 +404,15 @@ async function unpackFactoryImage(factoryImagePath: string, image: DeviceImage,
       let entry: yauzl.Entry = entryP
       let entryName = entry.filename
 
-      let isInnerZip =
-        entryName.includes(`-${image.buildId.toLowerCase()}/image-${image.deviceConfig.device.name}`) &&
-        entryName.endsWith(`-${image.buildId.toLowerCase()}.zip`)
+      let isInnerZip = false
+
+      let deviceName = image.deviceConfig.device.name
+      if (image.isGrapheneOS) {
+        isInnerZip = entryName.includes(`/image-${deviceName}-`) && entryName.endsWith('.zip')
+      } else {
+        isInnerZip = entryName.includes(`-${image.buildId.toLowerCase()}/image-${deviceName}`) &&
+          entryName.endsWith(`-${image.buildId.toLowerCase()}.zip`)
+      }
 
       if (!isInnerZip) {
         continue

src/images/device-image.ts

@@ -5,6 +5,8 @@ import { DeviceConfig, getDeviceBuildId } from '../config/device'
 import { IMAGE_DOWNLOAD_DIR } from '../config/paths'
 import { BuildIndex, DEFAULT_BASE_DOWNLOAD_URL, ImageType } from './build-index'
 
+const GRAPHENEOS_PSEUDO_BUILD_ID_PREFIX = 'gos-'
+
 export class DeviceImage {
   constructor(
     readonly deviceConfig: DeviceConfig,
@@ -13,8 +15,9 @@ export class DeviceImage {
     readonly fileName: string,
     readonly sha256: string,
     readonly url: string,
-  ) {
-  }
+    readonly skipSha256Check: boolean,
+    readonly isGrapheneOS: boolean,
+  ) {}
 
   getPath() {
     return path.join(IMAGE_DOWNLOAD_DIR, this.fileName)
@@ -32,6 +35,15 @@ export class DeviceImage {
     let deviceBuildId = getDeviceBuildId(deviceConfig, buildId)
     let buildProps = index.get(deviceBuildId)
     if (buildProps === undefined) {
+      if (buildId.startsWith(GRAPHENEOS_PSEUDO_BUILD_ID_PREFIX)) {
+        let fileName = deviceConfig.device.name + '-factory-' +
+            buildId.substring(GRAPHENEOS_PSEUDO_BUILD_ID_PREFIX.length) + '.zip'
+
+        let url = 'https://releases.grapheneos.org/' + fileName
+
+        return new DeviceImage(deviceConfig, type, buildId, fileName, 'no sha256', url, true, true)
+      }
+
       throw new Error(`no images for '${deviceBuildId}'`)
     }
 
@@ -54,7 +66,7 @@ export class DeviceImage {
       fileName = ending
       url = DEFAULT_BASE_DOWNLOAD_URL + fileName
     }
-    return new DeviceImage(deviceConfig, type, buildId, fileName, sha256, url)
+    return new DeviceImage(deviceConfig, type, buildId, fileName, sha256, url, false, false)
   }
 
   static async getMissing(arr: DeviceImage[]) {

src/images/download.ts

@@ -70,13 +70,21 @@ async function downloadImage(image: DeviceImage, outDir: string) {
 
   let sha256Digest: string = sha256.digest('hex')
   console.log('SHA-256: ' + sha256Digest)
-  assert(sha256Digest === image.sha256, 'SHA256 mismatch, expected ' + image.sha256)
+  if (image.skipSha256Check) {
+    console.warn('skipping SHA-256 check for ' + completeOutFile)
+  } else {
+    assert(sha256Digest === image.sha256, 'SHA256 mismatch, expected ' + image.sha256)
+  }
 
   await fs.rename(tmpOutFile, completeOutFile)
 }
 
 function logTermsAndConditionsNotice(images: DeviceImage[]) {
-  if (images.filter(i => i.type === ImageType.Factory || i.type === ImageType.Ota).length == 0) {
+  if (
+    images.filter(i => {
+      return !i.isGrapheneOS && (i.type === ImageType.Factory || i.type === ImageType.Ota)
+    }).length == 0
+  ) {
     // vendor images show T&C notice themselves as part of unpacking
     return
   }