recovery: autodetect filesystem type

* Multiple fstab lines (supported in android) cause recovery to fail
  to mount partitions if the fs type is not the same as the first
  fstab entry. So when we attempt to find an fstab entry that matches
  a path for an f2fs, ext4 or vfat type, check it against blkid's
  determination of what filesystem type it is. If there is a discrepancy,
  query fs_mgr for the next possible entry that matches that path until
  either we find one that is good, or run out of fstab entries.

* Also attempt to autodetect the filesystem type for mounting from
  update.zips.

Change-Id: Ib6f4535dd88ef714ae1ca6fb0ffae1c7dac0f7ce

6 files changed, 74 insertions, 3 deletions

diff --git a/Android.mk b/Android.mk
index a0f8818e..2b62b441 100644
--- a/Android.mk
+++ b/Android.mk
@@ -160,6 +160,7 @@ endif
 
 LOCAL_C_INCLUDES += \
     system/vold \
+    external/e2fsprogs/lib
 
 # Health HAL dependency
 LOCAL_STATIC_LIBRARIES := \
@@ -181,6 +182,8 @@ LOCAL_STATIC_LIBRARIES += \
     libbootloader_message \
     libfs_mgr \
     libext4_utils \
+    libext2_blkid \
+    libext2_uuid \
     libsparse \
     libreboot \
     libziparchive \
@@ -339,6 +342,8 @@ LOCAL_CFLAGS += -DMINIVOLD
 LOCAL_CFLAGS += -Wno-unused-parameter
 LOCAL_STATIC_LIBRARIES += \
     libext4_utils \
+    libext2_blkid \
+    libext2_uuid \
     libsparse \
     libmounts \
     libz \
@@ -365,7 +370,8 @@ LOCAL_C_INCLUDES += \
     external/libtar/listhash \
     external/openssl/include \
     external/zlib \
-    bionic/libc/bionic
+    bionic/libc/bionic \
+    external/e2fsprogs/lib
 
 include $(BUILD_EXECUTABLE)
 
diff --git a/roots.cpp b/roots.cpp
index 808958d8..c2b30cbb 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -44,6 +44,11 @@
 
 #include "mounts.h"
 
+#ifdef __bitwise
+#undef __bitwise
+#endif
+#include <blkid/blkid.h>
+
 static struct fstab* fstab = nullptr;
 
 extern struct selabel_handle* sehandle;
@@ -107,6 +112,34 @@ Volume* volume_for_mount_point(const std::string& mount_point) {
   return fs_mgr_get_entry_for_mount_point(fstab, mount_point);
 }
 
+Volume* get_entry_for_mount_point_detect_fs(const std::string& path) {
+  Volume* rec = fs_mgr_get_entry_for_mount_point(fstab, path);
+
+  if (rec == nullptr) {
+    return rec;
+  }
+
+  if (strcmp(rec->fs_type, "ext4") == 0 || strcmp(rec->fs_type, "f2fs") == 0 ||
+      strcmp(rec->fs_type, "vfat") == 0) {
+    char* detected_fs_type = blkid_get_tag_value(nullptr, "TYPE", rec->blk_device);
+
+    if (detected_fs_type == nullptr) {
+      return rec;
+    }
+
+    Volume* fetched_rec = rec;
+    while (rec != nullptr && strcmp(rec->fs_type, detected_fs_type) != 0) {
+      rec = fs_mgr_get_entry_for_mount_point_after(rec, fstab, path);
+    }
+
+    if (rec == nullptr) {
+      return fetched_rec;
+    }
+  }
+
+  return rec;
+}
+
 // Finds the volume specified by the given path. fs_mgr_get_entry_for_mount_point() does exact match
 // only, so it attempts the prefixes recursively (e.g. "/cache/recovery/last_log",
 // "/cache/recovery", "/cache", "/" for a given path of "/cache/recovery/last_log") and returns the
@@ -115,7 +148,7 @@ static Volume* volume_for_path(const char* path) {
   if (path == nullptr || path[0] == '\0') return nullptr;
   std::string str(path);
   while (true) {
-    Volume* result = fs_mgr_get_entry_for_mount_point(fstab, str);
+    Volume* result = get_entry_for_mount_point_detect_fs(str);
     if (result != nullptr || str == "/") {
       return result;
     }
diff --git a/tests/component/updater_test.cpp b/tests/component/updater_test.cpp
index 50e0a634..daf0c8c2 100644
--- a/tests/component/updater_test.cpp
+++ b/tests/component/updater_test.cpp
@@ -48,6 +48,11 @@
 #include "updater/install.h"
 #include "updater/updater.h"
 
+// For e2fsprogs
+extern "C" {
+const char* program_name = "updater";
+}
+
 struct selabel_handle *sehandle = nullptr;
 
 static void expect(const char* expected, const char* expr_str, CauseCode cause_code,
diff --git a/updater/Android.mk b/updater/Android.mk
index 0528e6cc..7d90ca38 100644
--- a/updater/Android.mk
+++ b/updater/Android.mk
@@ -101,6 +101,14 @@ LOCAL_STATIC_LIBRARIES := \
     $(TARGET_RECOVERY_UPDATER_EXTRA_LIBS) \
     $(updater_common_static_libraries)
 
+# XXX: this does not seem to work, why?
+# LOCAL_HEADER_LIBRARIES := libext2-headers
+
+LOCAL_C_INCLUDES += \
+    bootable/recovery/otafault \
+    external/e2fsprogs/lib
+LOCAL_STATIC_LIBRARIES += libext2_blkid libext2_uuid
+
 # Each library in TARGET_RECOVERY_UPDATER_LIBS should have a function
 # named "Register_<libname>()".  Here we emit a little C function that
 # gets #included by updater.c.  It calls all those registration
diff --git a/updater/install.cpp b/updater/install.cpp
index b91498a7..ae6d1168 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -16,6 +16,7 @@
 
 #include "updater/install.h"
 
+#include <blkid/blkid.h>
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -406,7 +407,7 @@ Value* MountFn(const char* name, State* state, const std::vector<std::unique_ptr
   if (!ReadArgs(state, argv, &args)) {
     return ErrorAbort(state, kArgsParsingFailure, "%s() Failed to parse the argument(s)", name);
   }
-  const std::string& fs_type = args[0];
+  std::string& fs_type = args[0];
   const std::string& partition_type = args[1];
   const std::string& location = args[2];
   const std::string& mount_point = args[3];
@@ -447,6 +448,19 @@ Value* MountFn(const char* name, State* state, const std::vector<std::unique_ptr
     }
   }
 
+  std::string detected_fs_type;
+  char* val = blkid_get_tag_value(NULL, "TYPE", location.c_str());
+  if (val) {
+    detected_fs_type = val;
+  }
+  if (!detected_fs_type.empty()) {
+    uiPrintf(state, "detected filesystem %s for %s\n", detected_fs_type.c_str(), location.c_str());
+    fs_type = detected_fs_type;
+  } else {
+    uiPrintf(state, "could not detect filesystem for %s, assuming %s\n", location.c_str(),
+             fs_type.c_str());
+  }
+
   if (mount(location.c_str(), mount_point.c_str(), fs_type.c_str(),
             MS_NOATIME | MS_NODEV | MS_NODIRATIME, mount_options.c_str()) < 0) {
     uiPrintf(state, "%s: Failed to mount %s at %s: %s", name, location.c_str(), mount_point.c_str(),
diff --git a/updater/updater.cpp b/updater/updater.cpp
index 1d6b172b..5cad6ba1 100644
--- a/updater/updater.cpp
+++ b/updater/updater.cpp
@@ -44,6 +44,11 @@
 // registration functions for device-specific extensions.
 #include "register.inc"
 
+// For e2fsprogs
+extern "C" {
+const char* program_name = "updater";
+}
+
 // Where in the package we expect to find the edify script to execute.
 // (Note it's "updateR-script", not the older "update-script".)
 static constexpr const char* SCRIPT_NAME = "META-INF/com/google/android/updater-script";