blobs: Add code to extract, mount, and flatten APEX modules

src/blobs/apex.ts

@@ -0,0 +1,91 @@
+import { promises as fs } from 'fs'
+import * as path from 'path'
+import * as unzipit from 'unzipit'
+
+import { listFilesRecursive, TempState } from '../util/fs'
+import { run } from '../util/process'
+import { NodeFileReader } from '../util/zip'
+import { BlobEntry } from './entry'
+import { combinedPartPathToEntry } from './file_list'
+
+export const ANDROID_INFO = 'android-info.txt'
+
+export type FirmwareImages = Map<string, ArrayBuffer>
+
+async function listPayload(partition: string, apexName: string, img: ArrayBuffer, tmp: TempState) {
+  // Extract image
+  let imgPath = `${tmp.dir}/apex_payload.img`
+  await fs.writeFile(imgPath, new DataView(img))
+
+  // Mount
+  let mountPoint = `${tmp.dir}/payload`
+  await fs.mkdir(mountPoint)
+  await run(`mount -t ext4 -o ro ${imgPath} ${mountPoint}`)
+  tmp.mounts.push(mountPoint)
+
+  // Extract files, including apex_metadata.pb
+  let entries: Array<BlobEntry> = []
+  for await (let file of listFilesRecursive(mountPoint)) {
+    let partPath = path.relative(mountPoint, file)
+    let entry = combinedPartPathToEntry(partition, `${partition}/apex/${apexName}/${partPath}`)
+    // I don't know of a way to make Soong copy files to a non-standard path ($part/apex/*)
+    entry.disableSoong = true
+    // Copy directly from mounted image
+    entry.diskSrcPath = file
+
+    entries.push(entry)
+  }
+
+  return entries
+}
+
+export async function flattenApex(partition: string, zipPath: string, tmp: TempState) {
+  let apexName = path.basename(zipPath, '.apex')
+  let entries: Array<BlobEntry> = []
+  let reader = new NodeFileReader(zipPath)
+
+  try {
+    let { entries: zipEntries } = await unzipit.unzip(reader)
+
+    for (let [name, zipEntry] of Object.entries(zipEntries)) {
+      if (name == 'apex_pubkey') {
+        // Extract public key file to tmp
+        let pubkeyPath = `${tmp.dir}/apex_pubkey`
+        await fs.writeFile(pubkeyPath, new DataView(await zipEntry.arrayBuffer()))
+
+        // Add entry
+        let entry = combinedPartPathToEntry(partition, `${partition}/apex/${apexName}/apex_pubkey`)
+        entry.diskSrcPath = pubkeyPath
+        entries.push(entry)
+      } else if (name == 'apex_payload.img') {
+        // Mount and add payload files as entries
+        let img = await zipEntry.arrayBuffer()
+        let payloadEntries = await listPayload(partition, apexName, img, tmp)
+        entries.push(...payloadEntries)
+      }
+    }
+
+    return entries
+  } finally {
+    await reader.close()
+  }
+}
+
+export async function flattenAllApexs(rawEntries: Array<BlobEntry>, srcDir: string, tmp: TempState) {
+  let entries = new Set(rawEntries)
+  for (let entry of rawEntries) {
+    if (path.extname(entry.path) != '.apex') {
+      continue
+    }
+
+    // Flatten and add new entries
+    let apexPath = `${srcDir}/${entry.srcPath}`
+    let apexEntries = await flattenApex(entry.partition, apexPath, tmp)
+    apexEntries.forEach(e => entries.add(e))
+
+    // Remove the APEX blob entry
+    entries.delete(entry)
+  }
+
+  return Array.from(entries)
+}