Support starting fuse from a block map

Factor out a new function from ApplyFromSdcard that installs a package
from a local path. Inside this function, we start the fuse and choose the
type of data provider depending on the path string. And similar to the
existing logic, we treat the package as a block map if the path starts
with a '@'.

This is part of the effort to install larger than 2GiB packages on ILP32
devices.

Bug: 127071893
Test: Build a 32 bit sailfish and create a 3GiB OTA package. Sideload
the package, uncrypt and install the package from sdcard.

Change-Id: I328ea34fa530731acbce7554bfc3059313ad6ece

fuse_sideload/fuse_provider.cpp

@@ -49,6 +49,11 @@ FuseFileDataProvider::FuseFileDataProvider(const std::string& path, uint32_t blo
   fuse_block_size_ = block_size;
 }
 
+std::unique_ptr<FuseDataProvider> FuseFileDataProvider::CreateFromFile(const std::string& path,
+                                                                       uint32_t block_size) {
+  return std::make_unique<FuseFileDataProvider>(path, block_size);
+}
+
 bool FuseFileDataProvider::ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
                                                 uint32_t start_block) const {
   uint64_t offset = static_cast<uint64_t>(start_block) * fuse_block_size_;
@@ -127,7 +132,7 @@ bool FuseBlockDataProvider::ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch
   return true;
 }
 
-std::unique_ptr<FuseBlockDataProvider> FuseBlockDataProvider::CreateFromBlockMap(
+std::unique_ptr<FuseDataProvider> FuseBlockDataProvider::CreateFromBlockMap(
     const std::string& block_map_path, uint32_t fuse_block_size) {
   auto block_map = BlockMapData::ParseBlockMapFile(block_map_path);
   if (!block_map) {

fuse_sideload/include/fuse_provider.h

@@ -44,6 +44,8 @@ class FuseDataProvider {
   virtual bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
                                     uint32_t start_block) const = 0;
 
+  virtual bool Valid() const = 0;
+
   virtual void Close() {}
 
  protected:
@@ -60,10 +62,13 @@ class FuseFileDataProvider : public FuseDataProvider {
  public:
   FuseFileDataProvider(const std::string& path, uint32_t block_size);
 
+  static std::unique_ptr<FuseDataProvider> CreateFromFile(const std::string& path,
+                                                          uint32_t block_size);
+
   bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
                             uint32_t start_block) const override;
 
-  bool Valid() const {
+  bool Valid() const override {
     return fd_ != -1;
   }
 
@@ -78,14 +83,20 @@ class FuseFileDataProvider : public FuseDataProvider {
 class FuseBlockDataProvider : public FuseDataProvider {
  public:
   // Constructs the fuse provider from the block map.
-  static std::unique_ptr<FuseBlockDataProvider> CreateFromBlockMap(
-      const std::string& block_map_path, uint32_t fuse_block_size);
+  static std::unique_ptr<FuseDataProvider> CreateFromBlockMap(const std::string& block_map_path,
+                                                              uint32_t fuse_block_size);
 
   RangeSet ranges() const {
     return ranges_;
   }
+
   bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
                             uint32_t start_block) const override;
+
+  bool Valid() const override {
+    return fd_ != -1;
+  }
+
   void Close() override;
 
  private:

install/Android.bp

@@ -61,7 +61,7 @@ cc_library_static {
     srcs: [
         "adb_install.cpp",
         "asn1_decoder.cpp",
-        "fuse_sdcard_install.cpp",
+        "fuse_install.cpp",
         "install.cpp",
         "package.cpp",
         "verifier.cpp",

install/fuse_install.cpp

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "install/fuse_sdcard_install.h"
+#include "install/fuse_install.h"
 
 #include <dirent.h>
 #include <signal.h>
@@ -27,6 +27,7 @@
 #include <algorithm>
 #include <functional>
 #include <memory>
+#include <string>
 #include <vector>
 
 #include <android-base/logging.h>
@@ -74,7 +75,8 @@ static std::string BrowseDirectory(const std::string& path, Device* device, Reco
       // Skip "." and ".." entries.
       if (name == "." || name == "..") continue;
       dirs.push_back(name + "/");
-    } else if (de->d_type == DT_REG && android::base::EndsWithIgnoreCase(name, ".zip")) {
+    } else if (de->d_type == DT_REG && (android::base::EndsWithIgnoreCase(name, ".zip") ||
+                                        android::base::EndsWithIgnoreCase(name, ".map"))) {
       entries.push_back(name);
     }
   }
@@ -119,42 +121,37 @@ static std::string BrowseDirectory(const std::string& path, Device* device, Reco
   // Unreachable.
 }
 
-static bool StartSdcardFuse(const std::string& path) {
-  auto file_data_reader = std::make_unique<FuseFileDataProvider>(path, 65536);
+static bool StartInstallPackageFuse(std::string_view path) {
+  if (path.empty()) {
+    return false;
+  }
+
+  constexpr auto FUSE_BLOCK_SIZE = 65536;
+  bool is_block_map = android::base::ConsumePrefix(&path, "@");
+  auto file_data_reader =
+      is_block_map ? FuseBlockDataProvider::CreateFromBlockMap(std::string(path), FUSE_BLOCK_SIZE)
+                   : FuseFileDataProvider::CreateFromFile(std::string(path), FUSE_BLOCK_SIZE);
 
   if (!file_data_reader->Valid()) {
     return false;
   }
 
-  // The installation process expects to find the sdcard unmounted. Unmount it with MNT_DETACH so
-  // that our open file continues to work but new references see it as unmounted.
-  umount2("/sdcard", MNT_DETACH);
+  if (android::base::StartsWith(path, SDCARD_ROOT)) {
+    // The installation process expects to find the sdcard unmounted. Unmount it with MNT_DETACH so
+    // that our open file continues to work but new references see it as unmounted.
+    umount2(SDCARD_ROOT, MNT_DETACH);
+  }
 
   return run_fuse_sideload(std::move(file_data_reader)) == 0;
 }
 
-InstallResult ApplyFromSdcard(Device* device, RecoveryUI* ui) {
-  if (ensure_path_mounted(SDCARD_ROOT) != 0) {
-    LOG(ERROR) << "\n-- Couldn't mount " << SDCARD_ROOT << ".\n";
-    return INSTALL_ERROR;
-  }
-
-  std::string path = BrowseDirectory(SDCARD_ROOT, device, ui);
-  if (path.empty()) {
-    LOG(ERROR) << "\n-- No package file selected.\n";
-    ensure_path_unmounted(SDCARD_ROOT);
-    return INSTALL_ERROR;
-  }
-
-  ui->Print("\n-- Install %s ...\n", path.c_str());
-  SetSdcardUpdateBootloaderMessage();
-
+InstallResult InstallWithFuseFromPath(std::string_view path, RecoveryUI* ui) {
   // We used to use fuse in a thread as opposed to a process. Since accessing
   // through fuse involves going from kernel to userspace to kernel, it leads
   // to deadlock when a page fault occurs. (Bug: 26313124)
   pid_t child;
   if ((child = fork()) == 0) {
-    bool status = StartSdcardFuse(path);
+    bool status = StartInstallPackageFuse(path);
 
     _exit(status ? EXIT_SUCCESS : EXIT_FAILURE);
   }
@@ -203,6 +200,32 @@ InstallResult ApplyFromSdcard(Device* device, RecoveryUI* ui) {
     LOG(ERROR) << "Error exit from the fuse process: " << WEXITSTATUS(status);
   }
 
+  return result;
+}
+
+InstallResult ApplyFromSdcard(Device* device) {
+  auto ui = device->GetUI();
+  if (ensure_path_mounted(SDCARD_ROOT) != 0) {
+    LOG(ERROR) << "\n-- Couldn't mount " << SDCARD_ROOT << ".\n";
+    return INSTALL_ERROR;
+  }
+
+  std::string path = BrowseDirectory(SDCARD_ROOT, device, ui);
+  if (path.empty()) {
+    LOG(ERROR) << "\n-- No package file selected.\n";
+    ensure_path_unmounted(SDCARD_ROOT);
+    return INSTALL_ERROR;
+  }
+
+  // Hint the install function to read from a block map file.
+  if (android::base::EndsWithIgnoreCase(path, ".map")) {
+    path = "@" + path;
+  }
+
+  ui->Print("\n-- Install %s ...\n", path.c_str());
+  SetSdcardUpdateBootloaderMessage();
+
+  auto result = InstallWithFuseFromPath(path, ui);
   ensure_path_unmounted(SDCARD_ROOT);
   return result;
 }

install/include/install/fuse_install.h

@@ -16,8 +16,15 @@
 
 #pragma once
 
+#include <string_view>
+
 #include "install/install.h"
 #include "recovery_ui/device.h"
 #include "recovery_ui/ui.h"
 
-InstallResult ApplyFromSdcard(Device* device, RecoveryUI* ui);
+// Starts FUSE with the package from |path| as the data source. And installs the package from
+// |FUSE_SIDELOAD_HOST_PATHNAME|. The |path| can point to the location of a package zip file or a
+// block map file with the prefix '@'; e.g. /sdcard/package.zip, @/cache/recovery/block.map.
+InstallResult InstallWithFuseFromPath(std::string_view path, RecoveryUI* ui);
+
+InstallResult ApplyFromSdcard(Device* device);

minadbd/fuse_adb_provider.h

@@ -29,6 +29,10 @@ class FuseAdbDataProvider : public FuseDataProvider {
   bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
                             uint32_t start_block) const override;
 
+  bool Valid() const override {
+    return fd_ != -1;
+  }
+
  private:
   // The underlying source to read data from (i.e. the one that talks to the host).
   int fd_;

recovery.cpp

@@ -49,7 +49,7 @@
 #include "common.h"
 #include "fsck_unshare_blocks.h"
 #include "install/adb_install.h"
-#include "install/fuse_sdcard_install.h"
+#include "install/fuse_install.h"
 #include "install/install.h"
 #include "install/package.h"
 #include "install/wipe_data.h"
@@ -408,7 +408,7 @@ static Device::BuiltinAction PromptAndWait(Device* device, InstallResult status)
           status = ApplyFromAdb(device, false /* rescue_mode */, &reboot_action);
         } else {
           adb = false;
-          status = ApplyFromSdcard(device, ui);
+          status = ApplyFromSdcard(device);
         }
 
         ui->Print("\nInstall from %s completed with status %d.\n", adb ? "ADB" : "SD card", status);

tests/unit/fuse_provider_test.cpp

@@ -44,7 +44,8 @@ TEST(FuseBlockMapTest, CreateFromBlockMap_smoke) {
   ASSERT_TRUE(block_map_data);
   ASSERT_EQ(10000, block_map_data->file_size());
   ASSERT_EQ(4096, block_map_data->fuse_block_size());
-  ASSERT_EQ(RangeSet({ { 10, 11 }, { 20, 21 }, { 22, 23 } }), block_map_data->ranges());
+  ASSERT_EQ(RangeSet({ { 10, 11 }, { 20, 21 }, { 22, 23 } }),
+            static_cast<FuseBlockDataProvider*>(block_map_data.get())->ranges());
 }
 
 TEST(FuseBlockMapTest, ReadBlockAlignedData_smoke) {

tests/unit/fuse_sideload_test.cpp

@@ -40,6 +40,10 @@ class FuseTestDataProvider : public FuseDataProvider {
   bool ReadBlockAlignedData(uint8_t*, uint32_t, uint32_t) const override {
     return true;
   }
+
+  bool Valid() const override {
+    return true;
+  }
 };
 
 TEST(SideloadTest, run_fuse_sideload_wrong_parameters) {