Merge "aflags: show staged values for each flag." into main
diff --git a/core/config.mk b/core/config.mk
index 546858a..c6eeffa 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -885,6 +885,7 @@
     32.0 \
     33.0 \
     34.0 \
+    202404 \
     )
 
 .KATI_READONLY := \
diff --git a/tools/aconfig/Cargo.toml b/tools/aconfig/Cargo.toml
index 7112fd4..6bd0d06 100644
--- a/tools/aconfig/Cargo.toml
+++ b/tools/aconfig/Cargo.toml
@@ -5,6 +5,7 @@
     "aconfig_protos",
     "aconfig_storage_file",
     "aconfig_storage_read_api",
+    "aconfig_storage_write_api",
     "aflags",
     "printflags"
 ]
diff --git a/tools/aconfig/TEST_MAPPING b/tools/aconfig/TEST_MAPPING
index 26d6172..2f1694b 100644
--- a/tools/aconfig/TEST_MAPPING
+++ b/tools/aconfig/TEST_MAPPING
@@ -70,10 +70,18 @@
   ],
   "postsubmit": [
     {
+      // aconfig_storage_write_api unit tests
+      "name": "aconfig_storage_write_api.test"
+    },
+    {
       // aconfig_storage_read_api unit tests
       "name": "aconfig_storage_read_api.test"
     },
     {
+      // aconfig_storage write api rust integration tests
+      "name": "aconfig_storage_write_api.test.rust"
+    },
+    {
       // aconfig_storage read api rust integration tests
       "name": "aconfig_storage_read_api.test.rust"
     },
diff --git a/tools/aconfig/aconfig/src/commands.rs b/tools/aconfig/aconfig/src/commands.rs
index c1df16b..98dde44 100644
--- a/tools/aconfig/aconfig/src/commands.rs
+++ b/tools/aconfig/aconfig/src/commands.rs
@@ -31,7 +31,7 @@
     ParsedFlagExt, ProtoFlagMetadata, ProtoFlagPermission, ProtoFlagState, ProtoParsedFlag,
     ProtoParsedFlags, ProtoTracepoint,
 };
-use aconfig_storage_file::StorageFileSelection;
+use aconfig_storage_file::StorageFileType;
 
 pub struct Input {
     pub source: String,
@@ -237,7 +237,7 @@
 pub fn create_storage(
     caches: Vec<Input>,
     container: &str,
-    file: &StorageFileSelection,
+    file: &StorageFileType,
 ) -> Result<Vec<u8>> {
     let parsed_flags_vec: Vec<ProtoParsedFlags> = caches
         .into_iter()
diff --git a/tools/aconfig/aconfig/src/main.rs b/tools/aconfig/aconfig/src/main.rs
index 5a4f23c..69f5458 100644
--- a/tools/aconfig/aconfig/src/main.rs
+++ b/tools/aconfig/aconfig/src/main.rs
@@ -29,7 +29,7 @@
 mod dump;
 mod storage;
 
-use aconfig_storage_file::StorageFileSelection;
+use aconfig_storage_file::StorageFileType;
 use codegen::CodegenMode;
 use dump::DumpFormat;
 
@@ -138,7 +138,7 @@
                 .arg(
                     Arg::new("file")
                         .long("file")
-                        .value_parser(|s: &str| StorageFileSelection::try_from(s)),
+                        .value_parser(|s: &str| StorageFileType::try_from(s)),
                 )
                 .arg(Arg::new("cache").long("cache").action(ArgAction::Append).required(true))
                 .arg(Arg::new("out").long("out").required(true)),
@@ -285,7 +285,7 @@
             write_output_to_file_or_stdout(path, &output)?;
         }
         Some(("create-storage", sub_matches)) => {
-            let file = get_required_arg::<StorageFileSelection>(sub_matches, "file")
+            let file = get_required_arg::<StorageFileType>(sub_matches, "file")
                 .context("Invalid storage file selection")?;
             let cache = open_zero_or_more_files(sub_matches, "cache")?;
             let container = get_required_arg::<String>(sub_matches, "container")?;
diff --git a/tools/aconfig/aconfig/src/storage/flag_table.rs b/tools/aconfig/aconfig/src/storage/flag_table.rs
index 1381e89..b861c1f 100644
--- a/tools/aconfig/aconfig/src/storage/flag_table.rs
+++ b/tools/aconfig/aconfig/src/storage/flag_table.rs
@@ -17,7 +17,7 @@
 use crate::commands::assign_flag_ids;
 use crate::storage::FlagPackage;
 use aconfig_storage_file::{
-    get_table_size, FlagTable, FlagTableHeader, FlagTableNode, FILE_VERSION,
+    get_table_size, FlagTable, FlagTableHeader, FlagTableNode, FILE_VERSION, StorageFileType
 };
 use anyhow::{anyhow, Result};
 
@@ -25,6 +25,7 @@
     FlagTableHeader {
         version: FILE_VERSION,
         container: String::from(container),
+        file_type: StorageFileType::FlagMap as u8,
         file_size: 0,
         num_flags,
         bucket_offset: 0,
@@ -168,31 +169,32 @@
         let expected_header = FlagTableHeader {
             version: FILE_VERSION,
             container: String::from("system"),
-            file_size: 320,
+            file_type: StorageFileType::FlagMap as u8,
+            file_size: 321,
             num_flags: 8,
-            bucket_offset: 30,
-            node_offset: 98,
+            bucket_offset: 31,
+            node_offset: 99,
         };
         assert_eq!(header, &expected_header);
 
         let buckets: &Vec<Option<u32>> = &flag_table.as_ref().unwrap().buckets;
         let expected_bucket: Vec<Option<u32>> = vec![
-            Some(98),
-            Some(124),
+            Some(99),
+            Some(125),
             None,
             None,
             None,
-            Some(177),
+            Some(178),
             None,
-            Some(203),
+            Some(204),
             None,
-            Some(261),
+            Some(262),
             None,
             None,
             None,
             None,
             None,
-            Some(293),
+            Some(294),
             None,
         ];
         assert_eq!(buckets, &expected_bucket);
@@ -201,10 +203,10 @@
         assert_eq!(nodes.len(), 8);
 
         assert_eq!(nodes[0], new_expected_node(0, "enabled_ro", 1, 1, None));
-        assert_eq!(nodes[1], new_expected_node(0, "enabled_rw", 1, 2, Some(150)));
+        assert_eq!(nodes[1], new_expected_node(0, "enabled_rw", 1, 2, Some(151)));
         assert_eq!(nodes[2], new_expected_node(1, "disabled_ro", 1, 0, None));
         assert_eq!(nodes[3], new_expected_node(2, "enabled_ro", 1, 1, None));
-        assert_eq!(nodes[4], new_expected_node(1, "enabled_fixed_ro", 1, 1, Some(235)));
+        assert_eq!(nodes[4], new_expected_node(1, "enabled_fixed_ro", 1, 1, Some(236)));
         assert_eq!(nodes[5], new_expected_node(1, "enabled_ro", 1, 2, None));
         assert_eq!(nodes[6], new_expected_node(2, "enabled_fixed_ro", 1, 0, None));
         assert_eq!(nodes[7], new_expected_node(0, "disabled_rw", 1, 0, None));
diff --git a/tools/aconfig/aconfig/src/storage/flag_value.rs b/tools/aconfig/aconfig/src/storage/flag_value.rs
index 0d4b5b4..e40bbc1 100644
--- a/tools/aconfig/aconfig/src/storage/flag_value.rs
+++ b/tools/aconfig/aconfig/src/storage/flag_value.rs
@@ -17,13 +17,14 @@
 use crate::commands::assign_flag_ids;
 use crate::storage::FlagPackage;
 use aconfig_protos::ProtoFlagState;
-use aconfig_storage_file::{FlagValueHeader, FlagValueList, FILE_VERSION};
+use aconfig_storage_file::{FlagValueHeader, FlagValueList, FILE_VERSION, StorageFileType};
 use anyhow::{anyhow, Result};
 
 fn new_header(container: &str, num_flags: u32) -> FlagValueHeader {
     FlagValueHeader {
         version: FILE_VERSION,
         container: String::from(container),
+        file_type: StorageFileType::FlagVal as u8,
         file_size: 0,
         num_flags,
         boolean_value_offset: 0,
@@ -79,9 +80,10 @@
         let expected_header = FlagValueHeader {
             version: FILE_VERSION,
             container: String::from("system"),
-            file_size: 34,
+            file_type: StorageFileType::FlagVal as u8,
+            file_size: 35,
             num_flags: 8,
-            boolean_value_offset: 26,
+            boolean_value_offset: 27,
         };
         assert_eq!(header, &expected_header);
 
diff --git a/tools/aconfig/aconfig/src/storage/mod.rs b/tools/aconfig/aconfig/src/storage/mod.rs
index 29eb9c8..c818d79 100644
--- a/tools/aconfig/aconfig/src/storage/mod.rs
+++ b/tools/aconfig/aconfig/src/storage/mod.rs
@@ -26,7 +26,7 @@
     package_table::create_package_table,
 };
 use aconfig_protos::{ProtoParsedFlag, ProtoParsedFlags};
-use aconfig_storage_file::StorageFileSelection;
+use aconfig_storage_file::StorageFileType;
 
 pub struct FlagPackage<'a> {
     pub package_name: &'a str,
@@ -87,7 +87,7 @@
 pub fn generate_storage_file<'a, I>(
     container: &str,
     parsed_flags_vec_iter: I,
-    file: &StorageFileSelection,
+    file: &StorageFileType,
 ) -> Result<Vec<u8>>
 where
     I: Iterator<Item = &'a ProtoParsedFlags>,
@@ -95,15 +95,15 @@
     let packages = group_flags_by_package(parsed_flags_vec_iter);
 
     match file {
-        StorageFileSelection::PackageMap => {
+        StorageFileType::PackageMap => {
             let package_table = create_package_table(container, &packages)?;
             Ok(package_table.as_bytes())
         }
-        StorageFileSelection::FlagMap => {
+        StorageFileType::FlagMap => {
             let flag_table = create_flag_table(container, &packages)?;
             Ok(flag_table.as_bytes())
         }
-        StorageFileSelection::FlagVal => {
+        StorageFileType::FlagVal => {
             let flag_value = create_flag_value(container, &packages)?;
             Ok(flag_value.as_bytes())
         }
diff --git a/tools/aconfig/aconfig/src/storage/package_table.rs b/tools/aconfig/aconfig/src/storage/package_table.rs
index 4c08129..bc2da4d 100644
--- a/tools/aconfig/aconfig/src/storage/package_table.rs
+++ b/tools/aconfig/aconfig/src/storage/package_table.rs
@@ -17,7 +17,7 @@
 use anyhow::Result;
 
 use aconfig_storage_file::{
-    get_table_size, PackageTable, PackageTableHeader, PackageTableNode, FILE_VERSION,
+    get_table_size, PackageTable, PackageTableHeader, PackageTableNode, FILE_VERSION, StorageFileType
 };
 
 use crate::storage::FlagPackage;
@@ -26,6 +26,7 @@
     PackageTableHeader {
         version: FILE_VERSION,
         container: String::from(container),
+        file_type: StorageFileType::PackageMap as u8,
         file_size: 0,
         num_packages,
         bucket_offset: 0,
@@ -123,15 +124,16 @@
         let expected_header = PackageTableHeader {
             version: FILE_VERSION,
             container: String::from("system"),
-            file_size: 208,
+            file_type: StorageFileType::PackageMap as u8,
+            file_size: 209,
             num_packages: 3,
-            bucket_offset: 30,
-            node_offset: 58,
+            bucket_offset: 31,
+            node_offset: 59,
         };
         assert_eq!(header, &expected_header);
 
         let buckets: &Vec<Option<u32>> = &package_table.as_ref().unwrap().buckets;
-        let expected: Vec<Option<u32>> = vec![Some(58), None, None, Some(108), None, None, None];
+        let expected: Vec<Option<u32>> = vec![Some(59), None, None, Some(109), None, None, None];
         assert_eq!(buckets, &expected);
 
         let nodes: &Vec<PackageTableNode> = &package_table.as_ref().unwrap().nodes;
@@ -147,7 +149,7 @@
             package_name: String::from("com.android.aconfig.storage.test_1"),
             package_id: 0,
             boolean_offset: 0,
-            next_offset: Some(158),
+            next_offset: Some(159),
         };
         assert_eq!(nodes[1], second_node_expected);
         let third_node_expected = PackageTableNode {
diff --git a/tools/aconfig/aconfig_storage_file/src/flag_table.rs b/tools/aconfig/aconfig_storage_file/src/flag_table.rs
index d6e5c62..f9b3158 100644
--- a/tools/aconfig/aconfig_storage_file/src/flag_table.rs
+++ b/tools/aconfig/aconfig_storage_file/src/flag_table.rs
@@ -17,8 +17,11 @@
 //! flag table module defines the flag table file format and methods for serialization
 //! and deserialization
 
-use crate::AconfigStorageError::{self, BytesParseFail};
-use crate::{get_bucket_index, read_str_from_bytes, read_u16_from_bytes, read_u32_from_bytes};
+use crate::{
+    get_bucket_index, read_str_from_bytes, read_u16_from_bytes, read_u32_from_bytes,
+    read_u8_from_bytes,
+};
+use crate::{AconfigStorageError, StorageFileType};
 use anyhow::anyhow;
 use std::fmt;
 
@@ -27,6 +30,7 @@
 pub struct FlagTableHeader {
     pub version: u32,
     pub container: String,
+    pub file_type: u8,
     pub file_size: u32,
     pub num_flags: u32,
     pub bucket_offset: u32,
@@ -38,8 +42,11 @@
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         writeln!(
             f,
-            "Version: {}, Container: {}, File Size: {}",
-            self.version, self.container, self.file_size
+            "Version: {}, Container: {}, File Type: {:?}, File Size: {}",
+            self.version,
+            self.container,
+            StorageFileType::try_from(self.file_type),
+            self.file_size
         )?;
         writeln!(
             f,
@@ -58,6 +65,7 @@
         let container_bytes = self.container.as_bytes();
         result.extend_from_slice(&(container_bytes.len() as u32).to_le_bytes());
         result.extend_from_slice(container_bytes);
+        result.extend_from_slice(&self.file_type.to_le_bytes());
         result.extend_from_slice(&self.file_size.to_le_bytes());
         result.extend_from_slice(&self.num_flags.to_le_bytes());
         result.extend_from_slice(&self.bucket_offset.to_le_bytes());
@@ -68,14 +76,21 @@
     /// Deserialize from bytes
     pub fn from_bytes(bytes: &[u8]) -> Result<Self, AconfigStorageError> {
         let mut head = 0;
-        Ok(Self {
+        let table = Self {
             version: read_u32_from_bytes(bytes, &mut head)?,
             container: read_str_from_bytes(bytes, &mut head)?,
+            file_type: read_u8_from_bytes(bytes, &mut head)?,
             file_size: read_u32_from_bytes(bytes, &mut head)?,
             num_flags: read_u32_from_bytes(bytes, &mut head)?,
             bucket_offset: read_u32_from_bytes(bytes, &mut head)?,
             node_offset: read_u32_from_bytes(bytes, &mut head)?,
-        })
+        };
+        if table.file_type != StorageFileType::FlagMap as u8 {
+            return Err(AconfigStorageError::BytesParseFail(anyhow!(
+                "binary file is not a flag map"
+            )));
+        }
+        Ok(table)
     }
 }
 
@@ -191,7 +206,9 @@
                 Ok(node)
             })
             .collect::<Result<Vec<_>, AconfigStorageError>>()
-            .map_err(|errmsg| BytesParseFail(anyhow!("fail to parse flag table: {}", errmsg)))?;
+            .map_err(|errmsg| {
+                AconfigStorageError::BytesParseFail(anyhow!("fail to parse flag table: {}", errmsg))
+            })?;
 
         let table = Self { header, buckets, nodes };
         Ok(table)
@@ -219,9 +236,11 @@
             assert_eq!(node, &reinterpreted_node);
         }
 
-        let reinterpreted_table = FlagTable::from_bytes(&flag_table.as_bytes());
+        let flag_table_bytes = flag_table.as_bytes();
+        let reinterpreted_table = FlagTable::from_bytes(&flag_table_bytes);
         assert!(reinterpreted_table.is_ok());
         assert_eq!(&flag_table, &reinterpreted_table.unwrap());
+        assert_eq!(flag_table_bytes.len() as u32, header.file_size);
     }
 
     #[test]
@@ -234,4 +253,16 @@
         let version = read_u32_from_bytes(bytes, &mut head).unwrap();
         assert_eq!(version, 1234)
     }
+
+    #[test]
+    // this test point locks down file type check
+    fn test_file_type_check() {
+        let mut flag_table = create_test_flag_table();
+        flag_table.header.file_type = 123u8;
+        let error = FlagTable::from_bytes(&flag_table.as_bytes()).unwrap_err();
+        assert_eq!(
+            format!("{:?}", error),
+            format!("BytesParseFail(binary file is not a flag map)")
+        );
+    }
 }
diff --git a/tools/aconfig/aconfig_storage_file/src/flag_value.rs b/tools/aconfig/aconfig_storage_file/src/flag_value.rs
index 021546c..c9d09a1 100644
--- a/tools/aconfig/aconfig_storage_file/src/flag_value.rs
+++ b/tools/aconfig/aconfig_storage_file/src/flag_value.rs
@@ -17,8 +17,9 @@
 //! flag value module defines the flag value file format and methods for serialization
 //! and deserialization
 
-use crate::AconfigStorageError;
 use crate::{read_str_from_bytes, read_u32_from_bytes, read_u8_from_bytes};
+use crate::{AconfigStorageError, StorageFileType};
+use anyhow::anyhow;
 use std::fmt;
 
 /// Flag value header struct
@@ -26,6 +27,7 @@
 pub struct FlagValueHeader {
     pub version: u32,
     pub container: String,
+    pub file_type: u8,
     pub file_size: u32,
     pub num_flags: u32,
     pub boolean_value_offset: u32,
@@ -36,8 +38,11 @@
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         writeln!(
             f,
-            "Version: {}, Container: {}, File Size: {}",
-            self.version, self.container, self.file_size
+            "Version: {}, Container: {}, File Type: {:?}, File Size: {}",
+            self.version,
+            self.container,
+            StorageFileType::try_from(self.file_type),
+            self.file_size
         )?;
         writeln!(
             f,
@@ -56,6 +61,7 @@
         let container_bytes = self.container.as_bytes();
         result.extend_from_slice(&(container_bytes.len() as u32).to_le_bytes());
         result.extend_from_slice(container_bytes);
+        result.extend_from_slice(&self.file_type.to_le_bytes());
         result.extend_from_slice(&self.file_size.to_le_bytes());
         result.extend_from_slice(&self.num_flags.to_le_bytes());
         result.extend_from_slice(&self.boolean_value_offset.to_le_bytes());
@@ -65,13 +71,20 @@
     /// Deserialize from bytes
     pub fn from_bytes(bytes: &[u8]) -> Result<Self, AconfigStorageError> {
         let mut head = 0;
-        Ok(Self {
+        let list = Self {
             version: read_u32_from_bytes(bytes, &mut head)?,
             container: read_str_from_bytes(bytes, &mut head)?,
+            file_type: read_u8_from_bytes(bytes, &mut head)?,
             file_size: read_u32_from_bytes(bytes, &mut head)?,
             num_flags: read_u32_from_bytes(bytes, &mut head)?,
             boolean_value_offset: read_u32_from_bytes(bytes, &mut head)?,
-        })
+        };
+        if list.file_type != StorageFileType::FlagVal as u8 {
+            return Err(AconfigStorageError::BytesParseFail(anyhow!(
+                "binary file is not a flag value file"
+            )));
+        }
+        Ok(list)
     }
 }
 
@@ -130,9 +143,11 @@
         assert!(reinterpreted_header.is_ok());
         assert_eq!(header, &reinterpreted_header.unwrap());
 
-        let reinterpreted_value_list = FlagValueList::from_bytes(&flag_value_list.as_bytes());
+        let flag_value_bytes = flag_value_list.as_bytes();
+        let reinterpreted_value_list = FlagValueList::from_bytes(&flag_value_bytes);
         assert!(reinterpreted_value_list.is_ok());
         assert_eq!(&flag_value_list, &reinterpreted_value_list.unwrap());
+        assert_eq!(flag_value_bytes.len() as u32, header.file_size);
     }
 
     #[test]
@@ -145,4 +160,16 @@
         let version = read_u32_from_bytes(bytes, &mut head).unwrap();
         assert_eq!(version, 1234)
     }
+
+    #[test]
+    // this test point locks down file type check
+    fn test_file_type_check() {
+        let mut flag_value_list = create_test_flag_value_list();
+        flag_value_list.header.file_type = 123u8;
+        let error = FlagValueList::from_bytes(&flag_value_list.as_bytes()).unwrap_err();
+        assert_eq!(
+            format!("{:?}", error),
+            format!("BytesParseFail(binary file is not a flag value file)")
+        );
+    }
 }
diff --git a/tools/aconfig/aconfig_storage_file/src/lib.rs b/tools/aconfig/aconfig_storage_file/src/lib.rs
index 202f6a4..24b16a1 100644
--- a/tools/aconfig/aconfig_storage_file/src/lib.rs
+++ b/tools/aconfig/aconfig_storage_file/src/lib.rs
@@ -64,13 +64,13 @@
 
 /// Storage file type enum
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub enum StorageFileSelection {
-    PackageMap,
-    FlagMap,
-    FlagVal,
+pub enum StorageFileType {
+    PackageMap = 0,
+    FlagMap = 1,
+    FlagVal = 2,
 }
 
-impl TryFrom<&str> for StorageFileSelection {
+impl TryFrom<&str> for StorageFileType {
     type Error = anyhow::Error;
 
     fn try_from(value: &str) -> std::result::Result<Self, Self::Error> {
@@ -79,12 +79,25 @@
             "flag_map" => Ok(Self::FlagMap),
             "flag_val" => Ok(Self::FlagVal),
             _ => Err(anyhow!(
-                "Invalid storage file type, valid types are package_map|flag_map|flag_val]"
+                "Invalid storage file type, valid types are package_map|flag_map|flag_val"
             )),
         }
     }
 }
 
+impl TryFrom<u8> for StorageFileType {
+    type Error = anyhow::Error;
+
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        match value {
+            x if x == Self::PackageMap as u8 => Ok(Self::PackageMap),
+            x if x == Self::FlagMap as u8 => Ok(Self::FlagMap),
+            x if x == Self::FlagVal as u8 => Ok(Self::FlagVal),
+            _ => Err(anyhow!("Invalid storage file type")),
+        }
+    }
+}
+
 /// Get the right hash table size given number of entries in the table. Use a
 /// load factor of 0.5 for performance.
 pub fn get_table_size(entries: u32) -> Result<u32, AconfigStorageError> {
@@ -163,6 +176,12 @@
     #[error("fail to map storage file")]
     MapFileFail(#[source] anyhow::Error),
 
+    #[error("fail to get mapped file")]
+    ObtainMappedFileFail(#[source] anyhow::Error),
+
+    #[error("fail to flush mapped storage file")]
+    MapFlushFail(#[source] anyhow::Error),
+
     #[error("number of items in hash table exceed limit")]
     HashTableSizeLimit(#[source] anyhow::Error),
 
diff --git a/tools/aconfig/aconfig_storage_file/src/main.rs b/tools/aconfig/aconfig_storage_file/src/main.rs
index b5e6158..293d018 100644
--- a/tools/aconfig/aconfig_storage_file/src/main.rs
+++ b/tools/aconfig/aconfig_storage_file/src/main.rs
@@ -18,7 +18,7 @@
 
 use aconfig_storage_file::{
     list_flags, read_file_to_bytes, AconfigStorageError, FlagTable, FlagValueList, PackageTable,
-    StorageFileSelection,
+    StorageFileType,
 };
 
 use clap::{builder::ArgAction, Arg, Command};
@@ -33,7 +33,7 @@
                     Arg::new("type")
                         .long("type")
                         .required(true)
-                        .value_parser(|s: &str| StorageFileSelection::try_from(s)),
+                        .value_parser(|s: &str| StorageFileType::try_from(s)),
                 ),
         )
         .subcommand(
@@ -51,19 +51,19 @@
 
 fn print_storage_file(
     file_path: &str,
-    file_type: &StorageFileSelection,
+    file_type: &StorageFileType,
 ) -> Result<(), AconfigStorageError> {
     let bytes = read_file_to_bytes(file_path)?;
     match file_type {
-        StorageFileSelection::PackageMap => {
+        StorageFileType::PackageMap => {
             let package_table = PackageTable::from_bytes(&bytes)?;
             println!("{:?}", package_table);
         }
-        StorageFileSelection::FlagMap => {
+        StorageFileType::FlagMap => {
             let flag_table = FlagTable::from_bytes(&bytes)?;
             println!("{:?}", flag_table);
         }
-        StorageFileSelection::FlagVal => {
+        StorageFileType::FlagVal => {
             let flag_value = FlagValueList::from_bytes(&bytes)?;
             println!("{:?}", flag_value);
         }
@@ -76,7 +76,7 @@
     match matches.subcommand() {
         Some(("print", sub_matches)) => {
             let file_path = sub_matches.get_one::<String>("file").unwrap();
-            let file_type = sub_matches.get_one::<StorageFileSelection>("type").unwrap();
+            let file_type = sub_matches.get_one::<StorageFileType>("type").unwrap();
             print_storage_file(file_path, file_type)?
         }
         Some(("list", sub_matches)) => {
diff --git a/tools/aconfig/aconfig_storage_file/src/package_table.rs b/tools/aconfig/aconfig_storage_file/src/package_table.rs
index f7435b0..7cb60eb 100644
--- a/tools/aconfig/aconfig_storage_file/src/package_table.rs
+++ b/tools/aconfig/aconfig_storage_file/src/package_table.rs
@@ -17,8 +17,8 @@
 //! package table module defines the package table file format and methods for serialization
 //! and deserialization
 
-use crate::AconfigStorageError::{self, BytesParseFail};
-use crate::{get_bucket_index, read_str_from_bytes, read_u32_from_bytes};
+use crate::{get_bucket_index, read_str_from_bytes, read_u32_from_bytes, read_u8_from_bytes};
+use crate::{AconfigStorageError, StorageFileType};
 use anyhow::anyhow;
 use std::fmt;
 
@@ -27,6 +27,7 @@
 pub struct PackageTableHeader {
     pub version: u32,
     pub container: String,
+    pub file_type: u8,
     pub file_size: u32,
     pub num_packages: u32,
     pub bucket_offset: u32,
@@ -38,8 +39,11 @@
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         writeln!(
             f,
-            "Version: {}, Container: {}, File Size: {}",
-            self.version, self.container, self.file_size
+            "Version: {}, Container: {}, File Type: {:?}, File Size: {}",
+            self.version,
+            self.container,
+            StorageFileType::try_from(self.file_type),
+            self.file_size
         )?;
         writeln!(
             f,
@@ -58,6 +62,7 @@
         let container_bytes = self.container.as_bytes();
         result.extend_from_slice(&(container_bytes.len() as u32).to_le_bytes());
         result.extend_from_slice(container_bytes);
+        result.extend_from_slice(&self.file_type.to_le_bytes());
         result.extend_from_slice(&self.file_size.to_le_bytes());
         result.extend_from_slice(&self.num_packages.to_le_bytes());
         result.extend_from_slice(&self.bucket_offset.to_le_bytes());
@@ -68,14 +73,21 @@
     /// Deserialize from bytes
     pub fn from_bytes(bytes: &[u8]) -> Result<Self, AconfigStorageError> {
         let mut head = 0;
-        Ok(Self {
+        let table = Self {
             version: read_u32_from_bytes(bytes, &mut head)?,
             container: read_str_from_bytes(bytes, &mut head)?,
+            file_type: read_u8_from_bytes(bytes, &mut head)?,
             file_size: read_u32_from_bytes(bytes, &mut head)?,
             num_packages: read_u32_from_bytes(bytes, &mut head)?,
             bucket_offset: read_u32_from_bytes(bytes, &mut head)?,
             node_offset: read_u32_from_bytes(bytes, &mut head)?,
-        })
+        };
+        if table.file_type != StorageFileType::PackageMap as u8 {
+            return Err(AconfigStorageError::BytesParseFail(anyhow!(
+                "binary file is not a package map"
+            )));
+        }
+        Ok(table)
     }
 }
 
@@ -191,7 +203,12 @@
                 Ok(node)
             })
             .collect::<Result<Vec<_>, AconfigStorageError>>()
-            .map_err(|errmsg| BytesParseFail(anyhow!("fail to parse package table: {}", errmsg)))?;
+            .map_err(|errmsg| {
+                AconfigStorageError::BytesParseFail(anyhow!(
+                    "fail to parse package table: {}",
+                    errmsg
+                ))
+            })?;
 
         let table = Self { header, buckets, nodes };
         Ok(table)
@@ -218,9 +235,11 @@
             assert_eq!(node, &reinterpreted_node);
         }
 
-        let reinterpreted_table = PackageTable::from_bytes(&package_table.as_bytes());
+        let package_table_bytes = package_table.as_bytes();
+        let reinterpreted_table = PackageTable::from_bytes(&package_table_bytes);
         assert!(reinterpreted_table.is_ok());
         assert_eq!(&package_table, &reinterpreted_table.unwrap());
+        assert_eq!(package_table_bytes.len() as u32, header.file_size);
     }
 
     #[test]
@@ -233,4 +252,16 @@
         let version = read_u32_from_bytes(bytes, &mut head).unwrap();
         assert_eq!(version, 1234)
     }
+
+    #[test]
+    // this test point locks down file type check
+    fn test_file_type_check() {
+        let mut package_table = create_test_package_table();
+        package_table.header.file_type = 123u8;
+        let error = PackageTable::from_bytes(&package_table.as_bytes()).unwrap_err();
+        assert_eq!(
+            format!("{:?}", error),
+            format!("BytesParseFail(binary file is not a package map)")
+        );
+    }
 }
diff --git a/tools/aconfig/aconfig_storage_file/src/test_utils.rs b/tools/aconfig/aconfig_storage_file/src/test_utils.rs
index 7780044..586bb4c 100644
--- a/tools/aconfig/aconfig_storage_file/src/test_utils.rs
+++ b/tools/aconfig/aconfig_storage_file/src/test_utils.rs
@@ -17,7 +17,7 @@
 use crate::flag_table::{FlagTable, FlagTableHeader, FlagTableNode};
 use crate::flag_value::{FlagValueHeader, FlagValueList};
 use crate::package_table::{PackageTable, PackageTableHeader, PackageTableNode};
-use crate::AconfigStorageError;
+use crate::{AconfigStorageError, StorageFileType};
 
 use anyhow::anyhow;
 use std::io::Write;
@@ -27,12 +27,13 @@
     let header = PackageTableHeader {
         version: 1234,
         container: String::from("system"),
-        file_size: 208,
+        file_type: StorageFileType::PackageMap as u8,
+        file_size: 209,
         num_packages: 3,
-        bucket_offset: 30,
-        node_offset: 58,
+        bucket_offset: 31,
+        node_offset: 59,
     };
-    let buckets: Vec<Option<u32>> = vec![Some(58), None, None, Some(108), None, None, None];
+    let buckets: Vec<Option<u32>> = vec![Some(59), None, None, Some(109), None, None, None];
     let first_node = PackageTableNode {
         package_name: String::from("com.android.aconfig.storage.test_2"),
         package_id: 1,
@@ -43,7 +44,7 @@
         package_name: String::from("com.android.aconfig.storage.test_1"),
         package_id: 0,
         boolean_offset: 0,
-        next_offset: Some(158),
+        next_offset: Some(159),
     };
     let third_node = PackageTableNode {
         package_name: String::from("com.android.aconfig.storage.test_4"),
@@ -72,36 +73,37 @@
     let header = FlagTableHeader {
         version: 1234,
         container: String::from("system"),
-        file_size: 320,
+        file_type: StorageFileType::FlagMap as u8,
+        file_size: 321,
         num_flags: 8,
-        bucket_offset: 30,
-        node_offset: 98,
+        bucket_offset: 31,
+        node_offset: 99,
     };
     let buckets: Vec<Option<u32>> = vec![
-        Some(98),
-        Some(124),
+        Some(99),
+        Some(125),
         None,
         None,
         None,
-        Some(177),
+        Some(178),
         None,
-        Some(203),
+        Some(204),
         None,
-        Some(261),
+        Some(262),
         None,
         None,
         None,
         None,
         None,
-        Some(293),
+        Some(294),
         None,
     ];
     let nodes = vec![
         FlagTableNode::new_expected(0, "enabled_ro", 1, 1, None),
-        FlagTableNode::new_expected(0, "enabled_rw", 1, 2, Some(150)),
+        FlagTableNode::new_expected(0, "enabled_rw", 1, 2, Some(151)),
         FlagTableNode::new_expected(1, "disabled_ro", 1, 0, None),
         FlagTableNode::new_expected(2, "enabled_ro", 1, 1, None),
-        FlagTableNode::new_expected(1, "enabled_fixed_ro", 1, 1, Some(235)),
+        FlagTableNode::new_expected(1, "enabled_fixed_ro", 1, 1, Some(236)),
         FlagTableNode::new_expected(1, "enabled_ro", 1, 2, None),
         FlagTableNode::new_expected(2, "enabled_fixed_ro", 1, 0, None),
         FlagTableNode::new_expected(0, "disabled_rw", 1, 0, None),
@@ -113,9 +115,10 @@
     let header = FlagValueHeader {
         version: 1234,
         container: String::from("system"),
-        file_size: 34,
+        file_type: StorageFileType::FlagVal as u8,
+        file_size: 35,
         num_flags: 8,
-        boolean_value_offset: 26,
+        boolean_value_offset: 27,
     };
     let booleans: Vec<bool> = vec![false, true, false, false, true, true, false, true];
     FlagValueList { header, booleans }
diff --git a/tools/aconfig/aconfig_storage_read_api/Android.bp b/tools/aconfig/aconfig_storage_read_api/Android.bp
index 721f9a5..a8fde53 100644
--- a/tools/aconfig/aconfig_storage_read_api/Android.bp
+++ b/tools/aconfig/aconfig_storage_read_api/Android.bp
@@ -74,24 +74,3 @@
     whole_static_libs: ["libaconfig_storage_read_api_cxx_bridge"],
     export_include_dirs: ["include"],
 }
-
-genrule {
-    name: "ro.package.map",
-    out: ["tests/tmp.ro.package.map"],
-    srcs: ["tests/package.map"],
-    cmd: "rm -f $(out);cp -f $(in) $(out);chmod -w $(out)",
-}
-
-genrule {
-    name: "ro.flag.map",
-    out: ["tests/tmp.ro.flag.map"],
-    srcs: ["tests/flag.map"],
-    cmd: "rm -f $(out);cp -f $(in) $(out);chmod -w $(out)",
-}
-
-genrule {
-    name: "ro.flag.val",
-    out: ["tests/tmp.ro.flag.val"],
-    srcs: ["tests/flag.val"],
-    cmd: "rm -f $(out);cp -f $(in) $(out);chmod -w $(out)",
-}
diff --git a/tools/aconfig/aconfig_storage_read_api/src/flag_table_query.rs b/tools/aconfig/aconfig_storage_read_api/src/flag_table_query.rs
index cc05557..403badb 100644
--- a/tools/aconfig/aconfig_storage_read_api/src/flag_table_query.rs
+++ b/tools/aconfig/aconfig_storage_read_api/src/flag_table_query.rs
@@ -65,7 +65,7 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use aconfig_storage_file::FlagTable;
+    use aconfig_storage_file::{StorageFileType, FlagTable};
 
     // create test baseline, syntactic sugar
     fn new_expected_node(
@@ -88,36 +88,37 @@
         let header = FlagTableHeader {
             version: crate::FILE_VERSION,
             container: String::from("system"),
-            file_size: 320,
+            file_type: StorageFileType::FlagMap as u8,
+            file_size: 321,
             num_flags: 8,
-            bucket_offset: 30,
-            node_offset: 98,
+            bucket_offset: 31,
+            node_offset: 99,
         };
         let buckets: Vec<Option<u32>> = vec![
-            Some(98),
-            Some(124),
+            Some(99),
+            Some(125),
             None,
             None,
             None,
-            Some(177),
+            Some(178),
             None,
-            Some(203),
+            Some(204),
             None,
-            Some(261),
+            Some(262),
             None,
             None,
             None,
             None,
             None,
-            Some(293),
+            Some(294),
             None,
         ];
         let nodes = vec![
             new_expected_node(0, "enabled_ro", 1, 1, None),
-            new_expected_node(0, "enabled_rw", 1, 2, Some(150)),
+            new_expected_node(0, "enabled_rw", 1, 2, Some(151)),
             new_expected_node(1, "disabled_ro", 1, 0, None),
             new_expected_node(2, "enabled_ro", 1, 1, None),
-            new_expected_node(1, "enabled_fixed_ro", 1, 1, Some(235)),
+            new_expected_node(1, "enabled_fixed_ro", 1, 1, Some(236)),
             new_expected_node(1, "enabled_ro", 1, 2, None),
             new_expected_node(2, "enabled_fixed_ro", 1, 0, None),
             new_expected_node(0, "disabled_rw", 1, 0, None),
diff --git a/tools/aconfig/aconfig_storage_read_api/src/flag_value_query.rs b/tools/aconfig/aconfig_storage_read_api/src/flag_value_query.rs
index 6ff6b05..4b7a65e 100644
--- a/tools/aconfig/aconfig_storage_read_api/src/flag_value_query.rs
+++ b/tools/aconfig/aconfig_storage_read_api/src/flag_value_query.rs
@@ -48,15 +48,16 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use aconfig_storage_file::FlagValueList;
+    use aconfig_storage_file::{StorageFileType, FlagValueList};
 
     pub fn create_test_flag_value_list() -> FlagValueList {
         let header = FlagValueHeader {
             version: crate::FILE_VERSION,
             container: String::from("system"),
-            file_size: 34,
+            file_type: StorageFileType::FlagVal as u8,
+            file_size: 35,
             num_flags: 8,
-            boolean_value_offset: 26,
+            boolean_value_offset: 27,
         };
         let booleans: Vec<bool> = vec![false, true, false, false, true, true, false, true];
         FlagValueList { header, booleans }
diff --git a/tools/aconfig/aconfig_storage_read_api/src/lib.rs b/tools/aconfig/aconfig_storage_read_api/src/lib.rs
index 3958b2e..cb6a74a 100644
--- a/tools/aconfig/aconfig_storage_read_api/src/lib.rs
+++ b/tools/aconfig/aconfig_storage_read_api/src/lib.rs
@@ -43,7 +43,7 @@
 mod test_utils;
 
 pub use aconfig_storage_file::{
-    protos::ProtoStorageFiles, read_u32_from_bytes, AconfigStorageError, StorageFileSelection,
+    protos::ProtoStorageFiles, read_u32_from_bytes, AconfigStorageError, StorageFileType,
     FILE_VERSION,
 };
 pub use flag_table_query::FlagOffset;
@@ -67,7 +67,7 @@
     container: &str,
     package: &str,
 ) -> Result<Option<PackageOffset>, AconfigStorageError> {
-    let mapped_file = get_mapped_file(pb_file, container, StorageFileSelection::PackageMap)?;
+    let mapped_file = get_mapped_file(pb_file, container, StorageFileType::PackageMap)?;
     find_package_offset(&mapped_file, package)
 }
 
@@ -78,7 +78,7 @@
     package_id: u32,
     flag: &str,
 ) -> Result<Option<FlagOffset>, AconfigStorageError> {
-    let mapped_file = get_mapped_file(pb_file, container, StorageFileSelection::FlagMap)?;
+    let mapped_file = get_mapped_file(pb_file, container, StorageFileType::FlagMap)?;
     find_flag_offset(&mapped_file, package_id, flag)
 }
 
@@ -88,7 +88,7 @@
     container: &str,
     offset: u32,
 ) -> Result<bool, AconfigStorageError> {
-    let mapped_file = get_mapped_file(pb_file, container, StorageFileSelection::FlagVal)?;
+    let mapped_file = get_mapped_file(pb_file, container, StorageFileType::FlagVal)?;
     find_boolean_flag_value(&mapped_file, offset)
 }
 
diff --git a/tools/aconfig/aconfig_storage_read_api/src/mapped_file.rs b/tools/aconfig/aconfig_storage_read_api/src/mapped_file.rs
index e94c56f..67c293c 100644
--- a/tools/aconfig/aconfig_storage_read_api/src/mapped_file.rs
+++ b/tools/aconfig/aconfig_storage_read_api/src/mapped_file.rs
@@ -15,7 +15,7 @@
  */
 
 use std::collections::HashMap;
-use std::fs::File;
+use std::fs::{self, File};
 use std::io::{BufReader, Read};
 use std::sync::{Arc, Mutex};
 
@@ -26,7 +26,7 @@
 use crate::AconfigStorageError::{
     self, FileReadFail, MapFileFail, ProtobufParseFail, StorageFileNotFound,
 };
-use crate::StorageFileSelection;
+use crate::StorageFileType;
 use aconfig_storage_file::protos::{
     storage_record_pb::try_from_binary_proto, ProtoStorageFileInfo, ProtoStorageFiles,
 };
@@ -75,17 +75,15 @@
 
 /// Verify the file is read only and then map it
 fn verify_read_only_and_map(file_path: &str) -> Result<Mmap, AconfigStorageError> {
-    let file = File::open(file_path)
-        .map_err(|errmsg| FileReadFail(anyhow!("Failed to open file {}: {}", file_path, errmsg)))?;
-    let metadata = file.metadata().map_err(|errmsg| {
-        FileReadFail(anyhow!("Failed to find metadata for {}: {}", file_path, errmsg))
-    })?;
-
-    // ensure storage file is read only
-    if !metadata.permissions().readonly() {
+    // ensure file has read only permission
+    let perms = fs::metadata(file_path).unwrap().permissions();
+    if !perms.readonly() {
         return Err(MapFileFail(anyhow!("fail to map non read only storage file {}", file_path)));
     }
 
+    let file = File::open(file_path)
+        .map_err(|errmsg| FileReadFail(anyhow!("Failed to open file {}: {}", file_path, errmsg)))?;
+
     // SAFETY:
     //
     // Mmap constructors are unsafe as it would have undefined behaviors if the file
@@ -95,10 +93,6 @@
     // which means it is read only. Here in the code, we check explicitly that the file
     // being mapped must only have read permission, otherwise, error out, thus making sure
     // it is safe.
-    //
-    // We should remove this restriction if we need to support mmap non read only file in
-    // the future (by making this api unsafe). But for now, all flags are boot stable, so
-    // the boot flag file copy should be readonly.
     unsafe {
         let mapped_file = Mmap::map(&file).map_err(|errmsg| {
             MapFileFail(anyhow!("fail to map storage file {}: {}", file_path, errmsg))
@@ -123,21 +117,21 @@
 pub(crate) fn get_mapped_file(
     location_pb_file: &str,
     container: &str,
-    file_selection: StorageFileSelection,
+    file_selection: StorageFileType,
 ) -> Result<Arc<Mmap>, AconfigStorageError> {
     let mut all_mapped_files = ALL_MAPPED_FILES.lock().unwrap();
     match all_mapped_files.get(container) {
         Some(mapped_files) => Ok(match file_selection {
-            StorageFileSelection::PackageMap => Arc::clone(&mapped_files.package_map),
-            StorageFileSelection::FlagMap => Arc::clone(&mapped_files.flag_map),
-            StorageFileSelection::FlagVal => Arc::clone(&mapped_files.flag_val),
+            StorageFileType::PackageMap => Arc::clone(&mapped_files.package_map),
+            StorageFileType::FlagMap => Arc::clone(&mapped_files.flag_map),
+            StorageFileType::FlagVal => Arc::clone(&mapped_files.flag_val),
         }),
         None => {
             let mapped_files = map_container_storage_files(location_pb_file, container)?;
             let file_ptr = match file_selection {
-                StorageFileSelection::PackageMap => Arc::clone(&mapped_files.package_map),
-                StorageFileSelection::FlagMap => Arc::clone(&mapped_files.flag_map),
-                StorageFileSelection::FlagVal => Arc::clone(&mapped_files.flag_val),
+                StorageFileType::PackageMap => Arc::clone(&mapped_files.package_map),
+                StorageFileType::FlagMap => Arc::clone(&mapped_files.flag_map),
+                StorageFileType::FlagVal => Arc::clone(&mapped_files.flag_val),
             };
             all_mapped_files.insert(container.to_string(), mapped_files);
             Ok(file_ptr)
@@ -196,11 +190,7 @@
         );
     }
 
-    fn map_and_verify(
-        location_pb_file: &str,
-        file_selection: StorageFileSelection,
-        actual_file: &str,
-    ) {
+    fn map_and_verify(location_pb_file: &str, file_selection: StorageFileType, actual_file: &str) {
         let mut opened_file = File::open(actual_file).unwrap();
         let mut content = Vec::new();
         opened_file.read_to_end(&mut content).unwrap();
@@ -238,13 +228,9 @@
 
         let file = write_proto_to_temp_file(&text_proto).unwrap();
         let file_full_path = file.path().display().to_string();
-        map_and_verify(
-            &file_full_path,
-            StorageFileSelection::PackageMap,
-            &ro_files.package_map.name,
-        );
-        map_and_verify(&file_full_path, StorageFileSelection::FlagMap, &ro_files.flag_map.name);
-        map_and_verify(&file_full_path, StorageFileSelection::FlagVal, &ro_files.flag_val.name);
+        map_and_verify(&file_full_path, StorageFileType::PackageMap, &ro_files.package_map.name);
+        map_and_verify(&file_full_path, StorageFileType::FlagMap, &ro_files.flag_map.name);
+        map_and_verify(&file_full_path, StorageFileType::FlagVal, &ro_files.flag_val.name);
     }
 
     #[test]
diff --git a/tools/aconfig/aconfig_storage_read_api/src/package_table_query.rs b/tools/aconfig/aconfig_storage_read_api/src/package_table_query.rs
index 6d2ed5f7..81feec6 100644
--- a/tools/aconfig/aconfig_storage_read_api/src/package_table_query.rs
+++ b/tools/aconfig/aconfig_storage_read_api/src/package_table_query.rs
@@ -72,18 +72,19 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use aconfig_storage_file::PackageTable;
+    use aconfig_storage_file::{StorageFileType, PackageTable};
 
     pub fn create_test_package_table() -> PackageTable {
         let header = PackageTableHeader {
             version: crate::FILE_VERSION,
             container: String::from("system"),
-            file_size: 208,
+            file_type: StorageFileType::PackageMap as u8,
+            file_size: 209,
             num_packages: 3,
-            bucket_offset: 30,
-            node_offset: 58,
+            bucket_offset: 31,
+            node_offset: 59,
         };
-        let buckets: Vec<Option<u32>> = vec![Some(58), None, None, Some(108), None, None, None];
+        let buckets: Vec<Option<u32>> = vec![Some(59), None, None, Some(109), None, None, None];
         let first_node = PackageTableNode {
             package_name: String::from("com.android.aconfig.storage.test_2"),
             package_id: 1,
@@ -94,7 +95,7 @@
             package_name: String::from("com.android.aconfig.storage.test_1"),
             package_id: 0,
             boolean_offset: 0,
-            next_offset: Some(158),
+            next_offset: Some(159),
         };
         let third_node = PackageTableNode {
             package_name: String::from("com.android.aconfig.storage.test_4"),
diff --git a/tools/aconfig/aconfig_storage_read_api/src/test_utils.rs b/tools/aconfig/aconfig_storage_read_api/src/test_utils.rs
index cc5938d..22f367f 100644
--- a/tools/aconfig/aconfig_storage_read_api/src/test_utils.rs
+++ b/tools/aconfig/aconfig_storage_read_api/src/test_utils.rs
@@ -26,14 +26,6 @@
     }
 }
 
-fn set_file_read_write(file: &NamedTempFile) {
-    let mut perms = fs::metadata(file.path()).unwrap().permissions();
-    if perms.readonly() {
-        perms.set_readonly(false);
-        fs::set_permissions(file.path(), perms).unwrap();
-    }
-}
-
 #[allow(dead_code)]
 pub(crate) struct TestStorageFile {
     pub file: NamedTempFile,
@@ -46,8 +38,6 @@
         fs::copy(source_file, file.path())?;
         if read_only {
             set_file_read_only(&file);
-        } else {
-            set_file_read_write(&file);
         }
         let name = file.path().display().to_string();
         Ok(Self { file, name })
diff --git a/tools/aconfig/aconfig_storage_read_api/tests/Android.bp b/tools/aconfig/aconfig_storage_read_api/tests/Android.bp
index 0bfc7bf..ab5ca44 100644
--- a/tools/aconfig/aconfig_storage_read_api/tests/Android.bp
+++ b/tools/aconfig/aconfig_storage_read_api/tests/Android.bp
@@ -10,9 +10,9 @@
         "libtempfile",
     ],
     data: [
-        ":ro.package.map",
-        ":ro.flag.map",
-        ":ro.flag.val",
+        "package.map",
+        "flag.map",
+        "flag.val",
     ],
     test_suites: ["general-tests"],
 }
@@ -31,9 +31,9 @@
         "liblog",
     ],
     data: [
-        ":ro.package.map",
-        ":ro.flag.map",
-        ":ro.flag.val",
+        "package.map",
+        "flag.map",
+        "flag.val",
     ],
     test_suites: [
         "device-tests",
diff --git a/tools/aconfig/aconfig_storage_read_api/tests/flag.map b/tools/aconfig/aconfig_storage_read_api/tests/flag.map
index 43b6f9a..5507894 100644
--- a/tools/aconfig/aconfig_storage_read_api/tests/flag.map
+++ b/tools/aconfig/aconfig_storage_read_api/tests/flag.map
Binary files differ
diff --git a/tools/aconfig/aconfig_storage_read_api/tests/flag.val b/tools/aconfig/aconfig_storage_read_api/tests/flag.val
index f39f8d3..75b8564 100644
--- a/tools/aconfig/aconfig_storage_read_api/tests/flag.val
+++ b/tools/aconfig/aconfig_storage_read_api/tests/flag.val
Binary files differ
diff --git a/tools/aconfig/aconfig_storage_read_api/tests/package.map b/tools/aconfig/aconfig_storage_read_api/tests/package.map
index 8ed4767..02267e5 100644
--- a/tools/aconfig/aconfig_storage_read_api/tests/package.map
+++ b/tools/aconfig/aconfig_storage_read_api/tests/package.map
Binary files differ
diff --git a/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.cpp b/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.cpp
index 6fecd08..1fd7770 100644
--- a/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.cpp
+++ b/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.cpp
@@ -16,58 +16,104 @@
 
 #include <string>
 #include <vector>
+#include <cstdio>
 
+#include <sys/stat.h>
 #include "aconfig_storage/aconfig_storage_read_api.hpp"
 #include <gtest/gtest.h>
 #include <protos/aconfig_storage_metadata.pb.h>
 #include <android-base/file.h>
+#include <android-base/result.h>
 
 using android::aconfig_storage_metadata::storage_files;
+using ::android::base::ReadFileToString;
 using ::android::base::WriteStringToFile;
+using ::android::base::Result;
+using ::android::base::Error;
 using ::aconfig_storage::test_only_api::get_package_offset_impl;
 using ::aconfig_storage::test_only_api::get_flag_offset_impl;
 using ::aconfig_storage::test_only_api::get_boolean_flag_value_impl;
 using ::aconfig_storage::get_storage_file_version;
 
-void write_storage_location_pb_to_file(std::string const& file_path) {
-  auto const test_dir = android::base::GetExecutableDirectory();
-  auto proto = storage_files();
-  auto* info = proto.add_files();
-  info->set_version(0);
-  info->set_container("system");
-  info->set_package_map(test_dir + "/tests/tmp.ro.package.map");
-  info->set_flag_map(test_dir + "/tests/tmp.ro.flag.map");
-  info->set_flag_val(test_dir + "/tests/tmp.ro.flag.val");
-  info->set_timestamp(12345);
+class AconfigStorageTest : public ::testing::Test {
+ protected:
+  Result<std::string> copy_to_ro_temp_file(std::string const& source_file) {
+    auto temp_file = std::string(std::tmpnam(nullptr));
+    auto content = std::string();
+    if (!ReadFileToString(source_file, &content)) {
+      return Error() << "failed to read file: " << source_file;
+    }
+    if (!WriteStringToFile(content, temp_file)) {
+      return Error() << "failed to copy file: " << source_file;
+    }
+    if (chmod(temp_file.c_str(), S_IRUSR | S_IRGRP) == -1) {
+      return Error() << "failed to make file read only";
+    }
+    return temp_file;
+  }
 
-  auto content = std::string();
-  proto.SerializeToString(&content);
-  ASSERT_TRUE(WriteStringToFile(content, file_path))
-      << "Failed to write a file: " << file_path;
-}
+  Result<std::string> write_storage_location_pb_file(std::string const& package_map,
+                                                     std::string const& flag_map,
+                                                     std::string const& flag_val) {
+    auto temp_file = std::tmpnam(nullptr);
+    auto proto = storage_files();
+    auto* info = proto.add_files();
+    info->set_version(0);
+    info->set_container("system");
+    info->set_package_map(package_map);
+    info->set_flag_map(flag_map);
+    info->set_flag_val(flag_val);
+    info->set_timestamp(12345);
 
-TEST(AconfigStorageTest, test_storage_version_query) {
-  auto const test_dir = android::base::GetExecutableDirectory();
-  auto query = get_storage_file_version(test_dir + "/tests/tmp.ro.package.map");
+    auto content = std::string();
+    proto.SerializeToString(&content);
+    if (!WriteStringToFile(content, temp_file)) {
+      return Error() << "failed to write storage records pb file";
+    }
+    return temp_file;
+  }
+
+  void SetUp() override {
+    auto const test_dir = android::base::GetExecutableDirectory();
+    package_map = *copy_to_ro_temp_file(test_dir + "/package.map");
+    flag_map = *copy_to_ro_temp_file(test_dir + "/flag.map");
+    flag_val = *copy_to_ro_temp_file(test_dir + "/flag.val");
+    storage_record_pb = *write_storage_location_pb_file(
+        package_map, flag_map, flag_val);
+  }
+
+  void TearDown() override {
+    std::remove(package_map.c_str());
+    std::remove(flag_map.c_str());
+    std::remove(flag_val.c_str());
+    std::remove(storage_record_pb.c_str());
+  }
+
+  std::string package_map;
+  std::string flag_map;
+  std::string flag_val;
+  std::string storage_record_pb;
+};
+
+
+TEST_F(AconfigStorageTest, test_storage_version_query) {
+  auto query = get_storage_file_version(package_map);
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_EQ(query.version_number, 1);
-  query = get_storage_file_version(test_dir + "/tests/tmp.ro.flag.map");
+  query = get_storage_file_version(flag_map);
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_EQ(query.version_number, 1);
-  query = get_storage_file_version(test_dir + "/tests/tmp.ro.flag.val");
+  query = get_storage_file_version(flag_val);
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_EQ(query.version_number, 1);
 }
 
-TEST(AconfigStorageTest, test_package_offset_query) {
-  auto pb_file = std::string("/tmp/test_package_offset_query.pb");
-  write_storage_location_pb_to_file(pb_file);
-
+TEST_F(AconfigStorageTest, test_package_offset_query) {
   auto query = get_package_offset_impl(
-      pb_file, "system", "com.android.aconfig.storage.test_1");
+      storage_record_pb, "system", "com.android.aconfig.storage.test_1");
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_TRUE(query.package_exists);
@@ -75,7 +121,7 @@
   ASSERT_EQ(query.boolean_offset, 0);
 
   query = get_package_offset_impl(
-      pb_file, "system", "com.android.aconfig.storage.test_2");
+      storage_record_pb, "system", "com.android.aconfig.storage.test_2");
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_TRUE(query.package_exists);
@@ -83,7 +129,7 @@
   ASSERT_EQ(query.boolean_offset, 3);
 
   query = get_package_offset_impl(
-      pb_file, "system", "com.android.aconfig.storage.test_4");
+      storage_record_pb, "system", "com.android.aconfig.storage.test_4");
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_TRUE(query.package_exists);
@@ -91,27 +137,21 @@
   ASSERT_EQ(query.boolean_offset, 6);
 }
 
-TEST(AconfigStorageTest, test_invalid_package_offset_query) {
-  auto pb_file = std::string("/tmp/test_package_offset_query.pb");
-  write_storage_location_pb_to_file(pb_file);
-
+TEST_F(AconfigStorageTest, test_invalid_package_offset_query) {
   auto query = get_package_offset_impl(
-      pb_file, "system", "com.android.aconfig.storage.test_3");
+      storage_record_pb, "system", "com.android.aconfig.storage.test_3");
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_FALSE(query.package_exists);
 
   query = get_package_offset_impl(
-      pb_file, "vendor", "com.android.aconfig.storage.test_1");
+      storage_record_pb, "vendor", "com.android.aconfig.storage.test_1");
   ASSERT_EQ(query.error_message,
             std::string("StorageFileNotFound(Storage file does not exist for vendor)"));
   ASSERT_FALSE(query.query_success);
 }
 
-TEST(AconfigStorageTest, test_flag_offset_query) {
-  auto pb_file = std::string("/tmp/test_package_offset_query.pb");
-  write_storage_location_pb_to_file(pb_file);
-
+TEST_F(AconfigStorageTest, test_flag_offset_query) {
   auto baseline = std::vector<std::tuple<int, std::string, int>>{
     {0, "enabled_ro", 1},
     {0, "enabled_rw", 2},
@@ -123,7 +163,7 @@
     {0, "disabled_rw", 0},
   };
   for (auto const&[package_id, flag_name, expected_offset] : baseline) {
-    auto query = get_flag_offset_impl(pb_file, "system", package_id, flag_name);
+    auto query = get_flag_offset_impl(storage_record_pb, "system", package_id, flag_name);
     ASSERT_EQ(query.error_message, std::string());
     ASSERT_TRUE(query.query_success);
     ASSERT_TRUE(query.flag_exists);
@@ -131,47 +171,39 @@
   }
 }
 
-TEST(AconfigStorageTest, test_invalid_flag_offset_query) {
-  auto pb_file = std::string("/tmp/test_invalid_package_offset_query.pb");
-  write_storage_location_pb_to_file(pb_file);
-
-  auto query = get_flag_offset_impl(pb_file, "system", 0, "none_exist");
+TEST_F(AconfigStorageTest, test_invalid_flag_offset_query) {
+  auto query = get_flag_offset_impl(storage_record_pb, "system", 0, "none_exist");
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_FALSE(query.flag_exists);
 
-  query = get_flag_offset_impl(pb_file, "system", 3, "enabled_ro");
+  query = get_flag_offset_impl(storage_record_pb, "system", 3, "enabled_ro");
   ASSERT_EQ(query.error_message, std::string());
   ASSERT_TRUE(query.query_success);
   ASSERT_FALSE(query.flag_exists);
 
-  query = get_flag_offset_impl(pb_file, "vendor", 0, "enabled_ro");
+  query = get_flag_offset_impl(storage_record_pb, "vendor", 0, "enabled_ro");
   ASSERT_EQ(query.error_message,
             std::string("StorageFileNotFound(Storage file does not exist for vendor)"));
   ASSERT_FALSE(query.query_success);
 }
 
-TEST(AconfigStorageTest, test_boolean_flag_value_query) {
-  auto pb_file = std::string("/tmp/test_boolean_flag_value_query.pb");
-  write_storage_location_pb_to_file(pb_file);
+TEST_F(AconfigStorageTest, test_boolean_flag_value_query) {
   for (int offset = 0; offset < 8; ++offset) {
-    auto query = get_boolean_flag_value_impl(pb_file, "system", offset);
+    auto query = get_boolean_flag_value_impl(storage_record_pb, "system", offset);
     ASSERT_EQ(query.error_message, std::string());
     ASSERT_TRUE(query.query_success);
     ASSERT_FALSE(query.flag_value);
   }
 }
 
-TEST(AconfigStorageTest, test_invalid_boolean_flag_value_query) {
-  auto pb_file = std::string("/tmp/test_invalid_boolean_flag_value_query.pb");
-  write_storage_location_pb_to_file(pb_file);
-
-  auto query = get_boolean_flag_value_impl(pb_file, "vendor", 0);
+TEST_F(AconfigStorageTest, test_invalid_boolean_flag_value_query) {
+  auto query = get_boolean_flag_value_impl(storage_record_pb, "vendor", 0);
   ASSERT_EQ(query.error_message,
             std::string("StorageFileNotFound(Storage file does not exist for vendor)"));
   ASSERT_FALSE(query.query_success);
 
-  query = get_boolean_flag_value_impl(pb_file, "system", 8);
+  query = get_boolean_flag_value_impl(storage_record_pb, "system", 8);
   ASSERT_EQ(query.error_message,
             std::string("InvalidStorageFileOffset(Flag value offset goes beyond the end of the file.)"));
   ASSERT_FALSE(query.query_success);
diff --git a/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.rs b/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.rs
index 4a65876..b178d83 100644
--- a/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.rs
+++ b/tools/aconfig/aconfig_storage_read_api/tests/storage_read_api_test.rs
@@ -5,22 +5,43 @@
         get_storage_file_version, PackageOffset, ProtoStorageFiles,
     };
     use protobuf::Message;
+    use std::fs;
     use std::io::Write;
     use tempfile::NamedTempFile;
 
-    fn write_storage_location_file() -> NamedTempFile {
-        let text_proto = r#"
-files {
+    pub fn copy_to_ro_temp_file(source_file: &str) -> NamedTempFile {
+        let file = NamedTempFile::new().unwrap();
+        fs::copy(source_file, file.path()).unwrap();
+        let file_name = file.path().display().to_string();
+        let mut perms = fs::metadata(file_name).unwrap().permissions();
+        perms.set_readonly(true);
+        fs::set_permissions(file.path(), perms.clone()).unwrap();
+        file
+    }
+
+    fn write_storage_location_file(
+        package_table: &NamedTempFile,
+        flag_table: &NamedTempFile,
+        flag_value: &NamedTempFile,
+    ) -> NamedTempFile {
+        let text_proto = format!(
+            r#"
+files {{
     version: 0
     container: "system"
-    package_map: "./tests/tmp.ro.package.map"
-    flag_map: "./tests/tmp.ro.flag.map"
-    flag_val: "./tests/tmp.ro.flag.val"
+    package_map: "{}"
+    flag_map: "{}"
+    flag_val: "{}"
     timestamp: 12345
-}
-"#;
+}}
+"#,
+            package_table.path().display(),
+            flag_table.path().display(),
+            flag_value.path().display(),
+        );
+
         let storage_files: ProtoStorageFiles =
-            protobuf::text_format::parse_from_str(text_proto).unwrap();
+            protobuf::text_format::parse_from_str(&text_proto).unwrap();
         let mut binary_proto_bytes = Vec::new();
         storage_files.write_to_vec(&mut binary_proto_bytes).unwrap();
         let mut file = NamedTempFile::new().unwrap();
@@ -30,7 +51,11 @@
 
     #[test]
     fn test_package_offset_query() {
-        let file = write_storage_location_file();
+        let package_table = copy_to_ro_temp_file("./package.map");
+        let flag_table = copy_to_ro_temp_file("./flag.map");
+        let flag_value = copy_to_ro_temp_file("./flag.val");
+
+        let file = write_storage_location_file(&package_table, &flag_table, &flag_value);
         let file_full_path = file.path().display().to_string();
 
         let package_offset = get_package_offset_impl(
@@ -74,7 +99,11 @@
 
     #[test]
     fn test_invalid_package_offset_query() {
-        let file = write_storage_location_file();
+        let package_table = copy_to_ro_temp_file("./package.map");
+        let flag_table = copy_to_ro_temp_file("./flag.map");
+        let flag_value = copy_to_ro_temp_file("./flag.val");
+
+        let file = write_storage_location_file(&package_table, &flag_table, &flag_value);
         let file_full_path = file.path().display().to_string();
 
         let package_offset_option = get_package_offset_impl(
@@ -99,7 +128,11 @@
 
     #[test]
     fn test_flag_offset_query() {
-        let file = write_storage_location_file();
+        let package_table = copy_to_ro_temp_file("./package.map");
+        let flag_table = copy_to_ro_temp_file("./flag.map");
+        let flag_value = copy_to_ro_temp_file("./flag.val");
+
+        let file = write_storage_location_file(&package_table, &flag_table, &flag_value);
         let file_full_path = file.path().display().to_string();
 
         let baseline = vec![
@@ -123,7 +156,11 @@
 
     #[test]
     fn test_invalid_flag_offset_query() {
-        let file = write_storage_location_file();
+        let package_table = copy_to_ro_temp_file("./package.map");
+        let flag_table = copy_to_ro_temp_file("./flag.map");
+        let flag_value = copy_to_ro_temp_file("./flag.val");
+
+        let file = write_storage_location_file(&package_table, &flag_table, &flag_value);
         let file_full_path = file.path().display().to_string();
 
         let flag_offset_option =
@@ -143,7 +180,11 @@
 
     #[test]
     fn test_boolean_flag_value_query() {
-        let file = write_storage_location_file();
+        let package_table = copy_to_ro_temp_file("./package.map");
+        let flag_table = copy_to_ro_temp_file("./flag.map");
+        let flag_value = copy_to_ro_temp_file("./flag.val");
+
+        let file = write_storage_location_file(&package_table, &flag_table, &flag_value);
         let file_full_path = file.path().display().to_string();
 
         let baseline: Vec<bool> = vec![false; 8];
@@ -156,7 +197,11 @@
 
     #[test]
     fn test_invalid_boolean_flag_value_query() {
-        let file = write_storage_location_file();
+        let package_table = copy_to_ro_temp_file("./package.map");
+        let flag_table = copy_to_ro_temp_file("./flag.map");
+        let flag_value = copy_to_ro_temp_file("./flag.val");
+
+        let file = write_storage_location_file(&package_table, &flag_table, &flag_value);
         let file_full_path = file.path().display().to_string();
 
         let err = get_boolean_flag_value_impl(&file_full_path, "vendor", 0u32).unwrap_err();
@@ -174,8 +219,8 @@
 
     #[test]
     fn test_storage_version_query() {
-        assert_eq!(get_storage_file_version("./tests/tmp.ro.package.map").unwrap(), 1);
-        assert_eq!(get_storage_file_version("./tests/tmp.ro.flag.map").unwrap(), 1);
-        assert_eq!(get_storage_file_version("./tests/tmp.ro.flag.val").unwrap(), 1);
+        assert_eq!(get_storage_file_version("./package.map").unwrap(), 1);
+        assert_eq!(get_storage_file_version("./flag.map").unwrap(), 1);
+        assert_eq!(get_storage_file_version("./flag.val").unwrap(), 1);
     }
 }
diff --git a/tools/aconfig/aconfig_storage_write_api/Android.bp b/tools/aconfig/aconfig_storage_write_api/Android.bp
new file mode 100644
index 0000000..1382aba
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/Android.bp
@@ -0,0 +1,37 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+rust_defaults {
+    name: "aconfig_storage_write_api.defaults",
+    edition: "2021",
+    lints: "none",
+    srcs: ["src/lib.rs"],
+    rustlibs: [
+        "libanyhow",
+        "libtempfile",
+        "libmemmap2",
+        "libcxx",
+        "libthiserror",
+        "libaconfig_storage_file",
+    ],
+}
+
+rust_library {
+    name: "libaconfig_storage_write_api",
+    crate_name: "aconfig_storage_write_api",
+    host_supported: true,
+    defaults: ["aconfig_storage_write_api.defaults"],
+}
+
+rust_test_host {
+    name: "aconfig_storage_write_api.test",
+    test_suites: ["general-tests"],
+    defaults: ["aconfig_storage_write_api.defaults"],
+    data: [
+        "tests/flag.val",
+    ],
+    rustlibs: [
+        "libaconfig_storage_read_api",
+    ],
+}
diff --git a/tools/aconfig/aconfig_storage_write_api/Cargo.toml b/tools/aconfig/aconfig_storage_write_api/Cargo.toml
new file mode 100644
index 0000000..494c19c
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+name = "aconfig_storage_write_api"
+version = "0.1.0"
+edition = "2021"
+
+[features]
+default = ["cargo"]
+cargo = []
+
+[dependencies]
+anyhow = "1.0.69"
+memmap2 = "0.8.0"
+tempfile = "3.9.0"
+thiserror = "1.0.56"
+protobuf = "3.2.0"
+once_cell = "1.19.0"
+aconfig_storage_file = { path = "../aconfig_storage_file" }
+aconfig_storage_read_api = { path = "../aconfig_storage_read_api" }
+
+[build-dependencies]
+cxx-build = "1.0"
diff --git a/tools/aconfig/aconfig_storage_write_api/src/flag_value_update.rs b/tools/aconfig/aconfig_storage_write_api/src/flag_value_update.rs
new file mode 100644
index 0000000..c2375dd
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/src/flag_value_update.rs
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//! flag value update module defines the flag value file write to mapped bytes
+
+use aconfig_storage_file::{AconfigStorageError, FlagValueHeader, FILE_VERSION};
+use anyhow::anyhow;
+
+/// Set flag value
+pub fn update_boolean_flag_value(
+    buf: &mut [u8],
+    flag_offset: u32,
+    flag_value: bool,
+) -> Result<(), AconfigStorageError> {
+    let interpreted_header = FlagValueHeader::from_bytes(buf)?;
+    if interpreted_header.version > FILE_VERSION {
+        return Err(AconfigStorageError::HigherStorageFileVersion(anyhow!(
+            "Cannot write to storage file with a higher version of {} with lib version {}",
+            interpreted_header.version,
+            FILE_VERSION
+        )));
+    }
+
+    let head = (interpreted_header.boolean_value_offset + flag_offset) as usize;
+
+    // TODO: right now, there is only boolean flags, with more flag value types added
+    // later, the end of boolean flag value section should be updated (b/322826265).
+    if head >= interpreted_header.file_size as usize {
+        return Err(AconfigStorageError::InvalidStorageFileOffset(anyhow!(
+            "Flag value offset goes beyond the end of the file."
+        )));
+    }
+
+    buf[head] = u8::from(flag_value).to_le_bytes()[0];
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use aconfig_storage_file::{FlagValueList, StorageFileType};
+
+    pub fn create_test_flag_value_list() -> FlagValueList {
+        let header = FlagValueHeader {
+            version: FILE_VERSION,
+            container: String::from("system"),
+            file_type: StorageFileType::FlagVal as u8,
+            file_size: 35,
+            num_flags: 8,
+            boolean_value_offset: 27,
+        };
+        let booleans: Vec<bool> = vec![false; 8];
+        FlagValueList { header, booleans }
+    }
+
+    #[test]
+    // this test point locks down flag value update
+    fn test_boolean_flag_value_update() {
+        let flag_value_list = create_test_flag_value_list();
+        let value_offset = flag_value_list.header.boolean_value_offset;
+        let mut content = flag_value_list.as_bytes();
+        let true_byte = u8::from(true).to_le_bytes()[0];
+        let false_byte = u8::from(false).to_le_bytes()[0];
+
+        for i in 0..flag_value_list.header.num_flags {
+            let offset = (value_offset + i) as usize;
+            update_boolean_flag_value(&mut content, i, true).unwrap();
+            assert_eq!(content[offset], true_byte);
+            update_boolean_flag_value(&mut content, i, false).unwrap();
+            assert_eq!(content[offset], false_byte);
+        }
+    }
+
+    #[test]
+    // this test point locks down update beyond the end of boolean section
+    fn test_boolean_out_of_range() {
+        let mut flag_value_list = create_test_flag_value_list().as_bytes();
+        let error = update_boolean_flag_value(&mut flag_value_list[..], 8, true).unwrap_err();
+        assert_eq!(
+            format!("{:?}", error),
+            "InvalidStorageFileOffset(Flag value offset goes beyond the end of the file.)"
+        );
+    }
+
+    #[test]
+    // this test point locks down query error when file has a higher version
+    fn test_higher_version_storage_file() {
+        let mut value_list = create_test_flag_value_list();
+        value_list.header.version = FILE_VERSION + 1;
+        let mut flag_value = value_list.as_bytes();
+        let error = update_boolean_flag_value(&mut flag_value[..], 4, true).unwrap_err();
+        assert_eq!(
+            format!("{:?}", error),
+            format!(
+                "HigherStorageFileVersion(Cannot write to storage file with a higher version of {} with lib version {})",
+                FILE_VERSION + 1,
+                FILE_VERSION
+            )
+        );
+    }
+}
diff --git a/tools/aconfig/aconfig_storage_write_api/src/lib.rs b/tools/aconfig/aconfig_storage_write_api/src/lib.rs
new file mode 100644
index 0000000..17a6538
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/src/lib.rs
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//! `aconfig_storage_write_api` is a crate that defines write apis to update flag value
+//! in storage file. It provides one api to interface with storage files.
+
+pub mod flag_value_update;
+pub mod mapped_file;
+
+#[cfg(test)]
+mod test_utils;
+
+use aconfig_storage_file::AconfigStorageError;
+
+use anyhow::anyhow;
+use memmap2::MmapMut;
+
+/// Storage file location pb file
+pub const STORAGE_LOCATION_FILE: &str = "/metadata/aconfig/persistent_storage_file_records.pb";
+
+/// Get mmaped flag value file given the container name
+///
+/// \input container: the flag package container
+/// \return a result of mapped file
+///
+///
+/// # Safety
+///
+/// The memory mapped file may have undefined behavior if there are writes to this
+/// file not thru this memory mapped file or there are concurrent writes to this
+/// memory mapped file. Ensure all writes to the underlying file are thru this memory
+/// mapped file and there are no concurrent writes.
+pub unsafe fn get_mapped_flag_value_file(container: &str) -> Result<MmapMut, AconfigStorageError> {
+    unsafe { crate::mapped_file::get_mapped_file(STORAGE_LOCATION_FILE, container) }
+}
+
+/// Set boolean flag value thru mapped file and flush the change to file
+///
+/// \input mapped_file: the mapped flag value file
+/// \input offset: flag value offset
+/// \input value: updated flag value
+/// \return a result of ()
+///
+pub fn set_boolean_flag_value(
+    file: &mut MmapMut,
+    offset: u32,
+    value: bool,
+) -> Result<(), AconfigStorageError> {
+    crate::flag_value_update::update_boolean_flag_value(file, offset, value)?;
+    file.flush().map_err(|errmsg| {
+        AconfigStorageError::MapFlushFail(anyhow!("fail to flush storage file: {}", errmsg))
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_utils::copy_to_temp_file;
+    use aconfig_storage_file::protos::storage_record_pb::write_proto_to_temp_file;
+    use aconfig_storage_read_api::flag_value_query::find_boolean_flag_value;
+    use std::fs::File;
+    use std::io::Read;
+
+    fn get_boolean_flag_value_at_offset(file: &str, offset: u32) -> bool {
+        let mut f = File::open(&file).unwrap();
+        let mut bytes = Vec::new();
+        f.read_to_end(&mut bytes).unwrap();
+        find_boolean_flag_value(&bytes, offset).unwrap()
+    }
+
+    #[test]
+    fn test_set_boolean_flag_value() {
+        let flag_value_file = copy_to_temp_file("./tests/flag.val", false).unwrap();
+        let flag_value_path = flag_value_file.path().display().to_string();
+        let text_proto = format!(
+            r#"
+files {{
+    version: 0
+    container: "system"
+    package_map: "some_package.map"
+    flag_map: "some_flag.map"
+    flag_val: "{}"
+    timestamp: 12345
+}}
+"#,
+            flag_value_path
+        );
+        let record_pb_file = write_proto_to_temp_file(&text_proto).unwrap();
+        let record_pb_path = record_pb_file.path().display().to_string();
+
+        // SAFETY:
+        // The safety here is guaranteed as only this single threaded test process will
+        // write to this file
+        unsafe {
+            let mut file = crate::mapped_file::get_mapped_file(&record_pb_path, "system").unwrap();
+            for i in 0..8 {
+                set_boolean_flag_value(&mut file, i, true).unwrap();
+                let value = get_boolean_flag_value_at_offset(&flag_value_path, i);
+                assert_eq!(value, true);
+
+                set_boolean_flag_value(&mut file, i, false).unwrap();
+                let value = get_boolean_flag_value_at_offset(&flag_value_path, i);
+                assert_eq!(value, false);
+            }
+        }
+    }
+}
diff --git a/tools/aconfig/aconfig_storage_write_api/src/mapped_file.rs b/tools/aconfig/aconfig_storage_write_api/src/mapped_file.rs
new file mode 100644
index 0000000..4c98be4
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/src/mapped_file.rs
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use std::fs::{self, File, OpenOptions};
+use std::io::{BufReader, Read};
+
+use anyhow::anyhow;
+use memmap2::MmapMut;
+
+use aconfig_storage_file::protos::{storage_record_pb::try_from_binary_proto, ProtoStorageFiles};
+use aconfig_storage_file::AconfigStorageError::{
+    self, FileReadFail, MapFileFail, ProtobufParseFail, StorageFileNotFound,
+};
+
+/// Find where persistent storage value file is for a particular container
+fn find_persist_flag_value_file(
+    location_pb_file: &str,
+    container: &str,
+) -> Result<String, AconfigStorageError> {
+    let file = File::open(location_pb_file).map_err(|errmsg| {
+        FileReadFail(anyhow!("Failed to open file {}: {}", location_pb_file, errmsg))
+    })?;
+    let mut reader = BufReader::new(file);
+    let mut bytes = Vec::new();
+    reader.read_to_end(&mut bytes).map_err(|errmsg| {
+        FileReadFail(anyhow!("Failed to read file {}: {}", location_pb_file, errmsg))
+    })?;
+    let storage_locations: ProtoStorageFiles = try_from_binary_proto(&bytes).map_err(|errmsg| {
+        ProtobufParseFail(anyhow!(
+            "Failed to parse storage location pb file {}: {}",
+            location_pb_file,
+            errmsg
+        ))
+    })?;
+    for location_info in storage_locations.files.iter() {
+        if location_info.container() == container {
+            return Ok(location_info.flag_val().to_string());
+        }
+    }
+    Err(StorageFileNotFound(anyhow!("Persistent flag value file does not exist for {}", container)))
+}
+
+/// Get a mapped storage file given the container and file type
+///
+/// # Safety
+///
+/// The memory mapped file may have undefined behavior if there are writes to this
+/// file not thru this memory mapped file or there are concurrent writes to this
+/// memory mapped file. Ensure all writes to the underlying file are thru this memory
+/// mapped file and there are no concurrent writes.
+pub unsafe fn get_mapped_file(
+    location_pb_file: &str,
+    container: &str,
+) -> Result<MmapMut, AconfigStorageError> {
+    let file_path = find_persist_flag_value_file(location_pb_file, container)?;
+
+    // make sure file has read write permission
+    let perms = fs::metadata(&file_path).unwrap().permissions();
+    if perms.readonly() {
+        return Err(MapFileFail(anyhow!("fail to map non read write storage file {}", file_path)));
+    }
+
+    let file =
+        OpenOptions::new().read(true).write(true).open(&file_path).map_err(|errmsg| {
+            FileReadFail(anyhow!("Failed to open file {}: {}", file_path, errmsg))
+        })?;
+
+    unsafe {
+        MmapMut::map_mut(&file).map_err(|errmsg| {
+            MapFileFail(anyhow!("fail to map storage file {}: {}", file_path, errmsg))
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_utils::copy_to_temp_file;
+    use aconfig_storage_file::protos::storage_record_pb::write_proto_to_temp_file;
+
+    #[test]
+    fn test_find_persist_flag_value_file_location() {
+        let text_proto = r#"
+files {
+    version: 0
+    container: "system"
+    package_map: "/system/etc/package.map"
+    flag_map: "/system/etc/flag.map"
+    flag_val: "/metadata/aconfig/system.val"
+    timestamp: 12345
+}
+files {
+    version: 1
+    container: "product"
+    package_map: "/product/etc/package.map"
+    flag_map: "/product/etc/flag.map"
+    flag_val: "/metadata/aconfig/product.val"
+    timestamp: 54321
+}
+"#;
+        let file = write_proto_to_temp_file(&text_proto).unwrap();
+        let file_full_path = file.path().display().to_string();
+        let flag_value_file = find_persist_flag_value_file(&file_full_path, "system").unwrap();
+        assert_eq!(flag_value_file, "/metadata/aconfig/system.val");
+        let flag_value_file = find_persist_flag_value_file(&file_full_path, "product").unwrap();
+        assert_eq!(flag_value_file, "/metadata/aconfig/product.val");
+        let err = find_persist_flag_value_file(&file_full_path, "vendor").unwrap_err();
+        assert_eq!(
+            format!("{:?}", err),
+            "StorageFileNotFound(Persistent flag value file does not exist for vendor)"
+        );
+    }
+
+    #[test]
+    fn test_mapped_file_contents() {
+        let mut rw_file = copy_to_temp_file("./tests/flag.val", false).unwrap();
+        let text_proto = format!(
+            r#"
+files {{
+    version: 0
+    container: "system"
+    package_map: "some_package.map"
+    flag_map: "some_flag.map"
+    flag_val: "{}"
+    timestamp: 12345
+}}
+"#,
+            rw_file.path().display().to_string()
+        );
+        let storage_record_file = write_proto_to_temp_file(&text_proto).unwrap();
+        let storage_record_file_path = storage_record_file.path().display().to_string();
+
+        let mut content = Vec::new();
+        rw_file.read_to_end(&mut content).unwrap();
+
+        // SAFETY:
+        // The safety here is guaranteed here as no writes happens to this temp file
+        unsafe {
+            let mmaped_file = get_mapped_file(&storage_record_file_path, "system").unwrap();
+            assert_eq!(mmaped_file[..], content[..]);
+        }
+    }
+
+    #[test]
+    fn test_mapped_read_only_file() {
+        let ro_file = copy_to_temp_file("./tests/flag.val", true).unwrap();
+        let text_proto = format!(
+            r#"
+files {{
+    version: 0
+    container: "system"
+    package_map: "some_package.map"
+    flag_map: "some_flag.map"
+    flag_val: "{}"
+    timestamp: 12345
+}}
+"#,
+            ro_file.path().display().to_string()
+        );
+        let storage_record_file = write_proto_to_temp_file(&text_proto).unwrap();
+        let storage_record_file_path = storage_record_file.path().display().to_string();
+
+        // SAFETY:
+        // The safety here is guaranteed here as no writes happens to this temp file
+        unsafe {
+            let error = get_mapped_file(&storage_record_file_path, "system").unwrap_err();
+            assert_eq!(
+                format!("{:?}", error),
+                format!(
+                    "MapFileFail(fail to map non read write storage file {})",
+                    ro_file.path().display().to_string()
+                )
+            );
+        }
+    }
+}
diff --git a/tools/aconfig/aconfig_storage_write_api/src/test_utils.rs b/tools/aconfig/aconfig_storage_write_api/src/test_utils.rs
new file mode 100644
index 0000000..06e2e22
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/src/test_utils.rs
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use anyhow::Result;
+use std::fs;
+use tempfile::NamedTempFile;
+
+/// Create temp file copy
+pub(crate) fn copy_to_temp_file(source_file: &str, read_only: bool) -> Result<NamedTempFile> {
+    let file = NamedTempFile::new()?;
+    fs::copy(source_file, file.path())?;
+    if read_only {
+        let file_name = file.path().display().to_string();
+        let mut perms = fs::metadata(file_name).unwrap().permissions();
+        perms.set_readonly(true);
+        fs::set_permissions(file.path(), perms.clone()).unwrap();
+    }
+    Ok(file)
+}
diff --git a/tools/aconfig/aconfig_storage_write_api/tests/Android.bp b/tools/aconfig/aconfig_storage_write_api/tests/Android.bp
new file mode 100644
index 0000000..bb8c6df
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/tests/Android.bp
@@ -0,0 +1,19 @@
+
+rust_test {
+    name: "aconfig_storage_write_api.test.rust",
+    srcs: [
+        "storage_write_api_test.rs"
+    ],
+    rustlibs: [
+        "libanyhow",
+        "libaconfig_storage_file",
+        "libaconfig_storage_read_api",
+        "libaconfig_storage_write_api",
+        "libprotobuf",
+        "libtempfile",
+    ],
+    data: [
+        "flag.val",
+    ],
+    test_suites: ["general-tests"],
+}
diff --git a/tools/aconfig/aconfig_storage_write_api/tests/flag.val b/tools/aconfig/aconfig_storage_write_api/tests/flag.val
new file mode 100644
index 0000000..75b8564
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/tests/flag.val
Binary files differ
diff --git a/tools/aconfig/aconfig_storage_write_api/tests/storage_write_api_test.rs b/tools/aconfig/aconfig_storage_write_api/tests/storage_write_api_test.rs
new file mode 100644
index 0000000..f6c1bbc
--- /dev/null
+++ b/tools/aconfig/aconfig_storage_write_api/tests/storage_write_api_test.rs
@@ -0,0 +1,73 @@
+#[cfg(not(feature = "cargo"))]
+mod aconfig_storage_write_api_test {
+    use aconfig_storage_file::protos::ProtoStorageFiles;
+    use aconfig_storage_read_api::flag_value_query::find_boolean_flag_value;
+    use aconfig_storage_write_api::{mapped_file::get_mapped_file, set_boolean_flag_value};
+
+    use protobuf::Message;
+    use std::fs::{self, File};
+    use std::io::{Read, Write};
+    use tempfile::NamedTempFile;
+
+    /// Write storage location record pb to a temp file
+    fn write_storage_record_file(flag_val: &str) -> NamedTempFile {
+        let text_proto = format!(
+            r#"
+files {{
+    version: 0
+    container: "system"
+    package_map: "some_package_map"
+    flag_map: "some_flag_map"
+    flag_val: "{}"
+    timestamp: 12345
+}}
+"#,
+            flag_val
+        );
+        let storage_files: ProtoStorageFiles =
+            protobuf::text_format::parse_from_str(&text_proto).unwrap();
+        let mut binary_proto_bytes = Vec::new();
+        storage_files.write_to_vec(&mut binary_proto_bytes).unwrap();
+        let mut file = NamedTempFile::new().unwrap();
+        file.write_all(&binary_proto_bytes).unwrap();
+        file
+    }
+
+    /// Create temp file copy
+    fn copy_to_temp_rw_file(source_file: &str) -> NamedTempFile {
+        let file = NamedTempFile::new().unwrap();
+        fs::copy(source_file, file.path()).unwrap();
+        file
+    }
+
+    /// Get boolean flag value from offset
+    fn get_boolean_flag_value_at_offset(file: &str, offset: u32) -> bool {
+        let mut f = File::open(file).unwrap();
+        let mut bytes = Vec::new();
+        f.read_to_end(&mut bytes).unwrap();
+        find_boolean_flag_value(&bytes, offset).unwrap()
+    }
+
+    #[test]
+    /// Test to lock down flag value update api
+    fn test_boolean_flag_value_update() {
+        let flag_value_file = copy_to_temp_rw_file("./flag.val");
+        let flag_value_path = flag_value_file.path().display().to_string();
+        let record_pb_file = write_storage_record_file(&flag_value_path);
+        let record_pb_path = record_pb_file.path().display().to_string();
+
+        // SAFETY:
+        // The safety here is ensured as only this single threaded test process will
+        // write to this file
+        let mut file = unsafe { get_mapped_file(&record_pb_path, "system").unwrap() };
+        for i in 0..8 {
+            set_boolean_flag_value(&mut file, i, true).unwrap();
+            let value = get_boolean_flag_value_at_offset(&flag_value_path, i);
+            assert!(value);
+
+            set_boolean_flag_value(&mut file, i, false).unwrap();
+            let value = get_boolean_flag_value_at_offset(&flag_value_path, i);
+            assert!(!value);
+        }
+    }
+}
diff --git a/tools/aconfig/aflags/src/device_config_source.rs b/tools/aconfig/aflags/src/device_config_source.rs
index 882120f..089f33d 100644
--- a/tools/aconfig/aflags/src/device_config_source.rs
+++ b/tools/aconfig/aflags/src/device_config_source.rs
@@ -105,11 +105,16 @@
     if !output.status.success() {
         let reason = match output.status.code() {
             Some(code) => {
-                format!("exit code {}, output was {}", code, str::from_utf8(&output.stdout)?)
+                let output = str::from_utf8(&output.stdout)?;
+                if !output.is_empty() {
+                    format!("exit code {code}, output was {output}")
+                } else {
+                    format!("exit code {code}")
+                }
             }
             None => "terminated by signal".to_string(),
         };
-        bail!("failed to execute device_config: {}", reason);
+        bail!("failed to access flag storage: {}", reason);
     }
     Ok(str::from_utf8(&output.stdout)?.to_string())
 }
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 52d95d8..5d92ede 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -822,6 +822,52 @@
   # Write back misc_info with the latest values.
   ReplaceMiscInfoTxt(input_tf_zip, output_tf_zip, misc_info)
 
+# Parse string output of `avbtool info_image`.
+def ParseAvbInfo(info_raw):
+  # line_matcher is for parsing each output line of `avbtool info_image`.
+  # example string input: "      Hash Algorithm:        sha1"
+  # example matched input: ("      ", "Hash Algorithm", "sha1")
+  line_matcher = re.compile(r'^(\s*)([^:]+):\s*(.*)$')
+  # prop_matcher is for parsing value part of 'Prop' in `avbtool info_image`.
+  # example string input: "example_prop_key -> 'example_prop_value'"
+  # example matched output: ("example_prop_key", "example_prop_value")
+  prop_matcher = re.compile(r"(.+)\s->\s'(.+)'")
+  info = {}
+  indent_stack = [[-1, info]]
+  for line_info_raw in info_raw.split('\n'):
+    # Parse the line
+    line_info_parsed = line_matcher.match(line_info_raw)
+    if not line_info_parsed:
+      continue
+    indent = len(line_info_parsed.group(1))
+    key = line_info_parsed.group(2).strip()
+    value = line_info_parsed.group(3).strip()
+
+    # Pop indentation stack
+    while indent <= indent_stack[-1][0]:
+      del indent_stack[-1]
+
+    # Insert information into 'info'.
+    cur_info = indent_stack[-1][1]
+    if value == "":
+      if key == "Descriptors":
+        empty_list = []
+        cur_info[key] = empty_list
+        indent_stack.append([indent, empty_list])
+      else:
+        empty_dict = {}
+        cur_info.append({key:empty_dict})
+        indent_stack.append([indent, empty_dict])
+    elif key == "Prop":
+      prop_parsed = prop_matcher.match(value)
+      if not prop_parsed:
+        raise ValueError(
+            "Failed to parse prop while getting avb information.")
+      cur_info.append({key:{prop_parsed.group(1):prop_parsed.group(2)}})
+    else:
+      cur_info[key] = value
+  return info
+
 def ReplaceKeyInAvbHashtreeFooter(image, new_key, new_algorithm, misc_info):
   # Get avb information about the image by parsing avbtool info_image.
   def GetAvbInfo(avbtool, image_name):
@@ -830,51 +876,7 @@
       avbtool, 'info_image',
       '--image', image_name
     ])
-
-    # line_matcher is for parsing each output line of `avbtool info_image`.
-    # example string input: "      Hash Algorithm:        sha1"
-    # example matched input: ("      ", "Hash Algorithm", "sha1")
-    line_matcher = re.compile(r'^(\s*)([^:]+):\s*(.*)$')
-    # prop_matcher is for parsing value part of 'Prop' in `avbtool info_image`.
-    # example string input: "example_prop_key -> 'example_prop_value'"
-    # example matched output: ("example_prop_key", "example_prop_value")
-    prop_matcher = re.compile(r"(.+)\s->\s'(.+)'")
-    info = {}
-    indent_stack = [[-1, info]]
-    for line_info_raw in info_raw.split('\n'):
-      # Parse the line
-      line_info_parsed = line_matcher.match(line_info_raw)
-      if not line_info_parsed:
-        continue
-      indent = len(line_info_parsed.group(1))
-      key = line_info_parsed.group(2).strip()
-      value = line_info_parsed.group(3).strip()
-
-      # Pop indentation stack
-      while indent <= indent_stack[-1][0]:
-        del indent_stack[-1]
-
-      # Insert information into 'info'.
-      cur_info = indent_stack[-1][1]
-      if value == "":
-        if key == "Descriptors":
-          empty_list = []
-          cur_info[key] = empty_list
-          indent_stack.append([indent, empty_list])
-        else:
-          empty_dict = {}
-          cur_info.append({key:empty_dict})
-          indent_stack.append([indent, empty_dict])
-      elif key == "Prop":
-        prop_parsed = prop_matcher.match(value)
-        if not prop_parsed:
-          raise ValueError(
-              "Failed to parse prop while getting avb information.")
-        cur_info.append({key:{prop_parsed.group(1):prop_parsed.group(2)}})
-      else:
-        cur_info[key] = value
-
-    return info
+    return ParseAvbInfo(info_raw)
 
   # Get hashtree descriptor from info
   def GetAvbHashtreeDescriptor(avb_info):
diff --git a/tools/releasetools/test_sign_target_files_apks.py b/tools/releasetools/test_sign_target_files_apks.py
index 9cc6df4..7ac1cff 100644
--- a/tools/releasetools/test_sign_target_files_apks.py
+++ b/tools/releasetools/test_sign_target_files_apks.py
@@ -22,8 +22,9 @@
 import common
 import test_utils
 from sign_target_files_apks import (
-    CheckApkAndApexKeysAvailable, EditTags, GetApkFileInfo, ReadApexKeysInfo,
-    ReplaceCerts, RewriteAvbProps, RewriteProps, WriteOtacerts)
+    CheckApkAndApexKeysAvailable, EditTags, GetApkFileInfo, ParseAvbInfo,
+    ReadApexKeysInfo, ReplaceCerts, RewriteAvbProps, RewriteProps,
+    WriteOtacerts)
 
 
 class SignTargetFilesApksTest(test_utils.ReleaseToolsTestCase):
@@ -535,3 +536,86 @@
             'system/apex/apexd/apexd_testdata/com.android.apex.test_package_2.pem',
             'build/make/target/product/security/testkey', None),
         }, keys_info)
+
+  def test_ParseAvbInfo(self):
+    avb_info_string = """
+    Footer version:           1.0
+    Image size:               9999999 bytes
+    Original image size:      8888888 bytes
+    VBMeta offset:            7777777
+    VBMeta size:              1111 bytes
+    --
+    Minimum libavb version:   1.0
+    Header Block:             222 bytes
+    Authentication Block:     333 bytes
+    Auxiliary Block:          888 bytes
+    Public key (sha1):        abababababababababababababababababababab
+    Algorithm:                SHA256_RSA2048
+    Rollback Index:           0
+    Flags:                    0
+    Rollback Index Location:  0
+    Release String:           'avbtool 1.3.0'
+    Descriptors:
+        Hashtree descriptor:
+          Version of dm-verity:  1
+          Image Size:            8888888 bytes
+          Tree Offset:           8888888
+          Tree Size:             44444 bytes
+          Data Block Size:       4444 bytes
+          Hash Block Size:       4444 bytes
+          FEC num roots:         0
+          FEC offset:            0
+          FEC size:              0 bytes
+          Hash Algorithm:        sha1
+          Partition Name:        partition-name
+          Salt:                  cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd
+          Root Digest:           efefefefefefefefefefefefefefefefefef
+          Flags:                 0
+        Prop: prop.key -> 'prop.value'
+    """
+
+    self.assertEqual(
+        {
+            'Footer version': '1.0',
+            'Image size': '9999999 bytes',
+            'Original image size': '8888888 bytes',
+            'VBMeta offset': '7777777',
+            'VBMeta size': '1111 bytes',
+            'Minimum libavb version': '1.0',
+            'Header Block': '222 bytes',
+            'Authentication Block': '333 bytes',
+            'Auxiliary Block': '888 bytes',
+            'Public key (sha1)': 'abababababababababababababababababababab',
+            'Algorithm': 'SHA256_RSA2048',
+            'Rollback Index': '0',
+            'Flags': '0',
+            'Rollback Index Location': '0',
+            'Release String': "'avbtool 1.3.0'",
+            'Descriptors': [
+                {
+                    'Hashtree descriptor': {
+                        'Version of dm-verity': '1',
+                        'Image Size': '8888888 bytes',
+                        'Tree Offset': '8888888',
+                        'Tree Size': '44444 bytes',
+                        'Data Block Size': '4444 bytes',
+                        'Hash Block Size': '4444 bytes',
+                        'FEC num roots': '0',
+                        'FEC offset': '0',
+                        'FEC size': '0 bytes',
+                        'Hash Algorithm': 'sha1',
+                        'Partition Name': 'partition-name',
+                        'Salt': 'cdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcdcd',
+                        'Root Digest': 'efefefefefefefefefefefefefefefefefef',
+                        'Flags': '0',
+                    }
+                },
+                {
+                    'Prop': {
+                        'prop.key': 'prop.value',
+                    }
+                },
+            ],
+        },
+        ParseAvbInfo(avb_info_string),
+    )
\ No newline at end of file