Merge pull request #832 from realm/add_checking_to_compact

added error checking to compact() and support encryption on Linux

README.md

@@ -28,18 +28,21 @@ each of our major platforms:
     sudo apt-get install build-essential
     sudo apt-get install python-cheetah
     sudo apt-get install libproc-dev
+    sudo apt-get install libssl-dev
 
 ### Linux Mint 15, 16, Ubuntu 13.04, 13.10
 
     sudo apt-get install build-essential
     sudo apt-get install python-cheetah
     sudo apt-get install libprocps0-dev
+    sudo apt-get install libssl-dev
 
 ### Linux Mint 17, 17.1, Ubuntu 14.04
 
     sudo apt-get install build-essential
     sudo apt-get install python-cheetah
     sudo apt-get install libprocps3-dev
+    sudo apt-get install libssl-dev
 
 ### Fedora 17, 18, 19, 20, Amazon Linux 2012.09
 

release_notes.md

@@ -58,10 +58,11 @@
 ### Enhancements:
 
 * Changes the mmap doubling treshold on mobile devices from 128MB to 16MB.
+* SharedGroup::compact() will now throw a runtime_error if called in detached state.
 
 ### Internals:
 
-* Lorem ipsum.
+* Can now be built with encryption enabled on Linux.
 
 ----------------------------------------------
 

src/project.mk

@@ -72,6 +72,9 @@ ifneq ($(REALM_HAVE_CONFIG),)
   endif
   ifeq ($(ENABLE_ENCRYPTION),yes)
     PROJECT_CFLAGS += -DREALM_ENABLE_ENCRYPTION
+    ifeq ($(OS),Linux)
+      PROJECT_LDFLAGS += -ldl
+    endif
   endif
 else
   ifneq ($(REALM_ENABLE_REPLICATION),)

src/realm/group_shared.cpp

@@ -837,6 +837,10 @@ void SharedGroup::open(const std::string& path, bool no_create_file,
 
 bool SharedGroup::compact()
 {
+    // Verify that the database file is attached
+    if (is_attached() == false) {
+        throw std::runtime_error(m_db_path + ": compact must be done on an open/attached SharedGroup");
+    }
     // Verify that preconditions for compacting is met:
     if (m_transact_stage != transact_Ready) {
         throw std::runtime_error(m_db_path + ": compact is not supported whithin a transaction");
@@ -887,7 +891,7 @@ bool SharedGroup::compact()
     // update the versioning info to match
     SharedInfo* r_info = m_reader_map.get_addr();
     Ringbuffer::ReadCount& rc = const_cast<Ringbuffer::ReadCount&>(r_info->readers.get_last());
-    REALM_ASSERT(rc.version == info->latest_version_number);
+    REALM_ASSERT_3(rc.version, ==, info->latest_version_number);
     rc.filesize = file_size;
     rc.current_top = top_ref;
     return true;

src/realm/group_shared.hpp

@@ -323,8 +323,9 @@ class SharedGroup {
 
     /// Compact the database file.
     /// - The method will throw if called inside a transaction.
+    /// - The method will throw if called in unattached state.
     /// - The method will return false if other SharedGroups are accessing the database
-    ///   in which case compaction is not done.
+    ///   in which case compaction is not done. This is not necessarily an error.
     /// It will return true following succesful compaction.
     /// While compaction is in progress, attempts by other
     /// threads or processes to open the database will wait.

src/realm/util/encrypted_file_mapping.cpp

@@ -73,10 +73,17 @@ AESCryptor::AESCryptor(const uint8_t* key) {
     CCCryptorCreate(kCCEncrypt, kCCAlgorithmAES, 0 /* options */, key, kCCKeySizeAES256, 0 /* IV */, &m_encr);
     CCCryptorCreate(kCCDecrypt, kCCAlgorithmAES, 0 /* options */, key, kCCKeySizeAES256, 0 /* IV */, &m_decr);
 #else
-#ifdef REALM_ANDROID
+
+#if defined(__linux__)
     // libcrypto isn't exposed as part of the NDK, but it happens to be loaded
     // into every process with every version of Android, so we can get to it
     // with dlsym
+    // FIXME: Don't know where to write the following info:
+    // on linux, we add -ldl to the linking step to get dlsym to work,
+    // and set LD_PRELOAD to the location of libcrypto when running the executable.
+    // (on linux mint this is currently: "LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libcrypto.so")
+    // To be able to debug with gdb, use the command "handle SIGSEGV noprint"
+    // before running the program.
     dlsym_cast(AES_set_encrypt_key, "AES_set_encrypt_key");
     dlsym_cast(AES_set_decrypt_key, "AES_set_decrypt_key");
     dlsym_cast(AES_cbc_encrypt, "AES_cbc_encrypt");
@@ -85,7 +92,6 @@ AESCryptor::AESCryptor(const uint8_t* key) {
     dlsym_cast(SHA256_Update, "SHA256_Update");
     dlsym_cast(SHA256_Final, "SHA256_Final");
 #endif
-
     AES_set_encrypt_key(key, 256 /* key size in bits */, &m_ectx);
     AES_set_decrypt_key(key, 256 /* key size in bits */, &m_dctx);
 #endif

src/realm/util/encrypted_file_mapping.hpp

@@ -86,7 +86,7 @@ class AESCryptor {
     AES_KEY m_dctx;
 #endif
 
-#ifdef REALM_ANDROID
+#if defined(__linux__)
     // Loaded at runtime with dysym
     int (*AES_set_encrypt_key)(const unsigned char *, const int, AES_KEY *);
     int (*AES_set_decrypt_key)(const unsigned char *, const int, AES_KEY *);

src/realm/util/file_mapper.cpp

@@ -41,6 +41,7 @@
 #include <realm/util/shared_ptr.hpp>
 #include <realm/util/terminate.hpp>
 #include <realm/util/thread.hpp>
+#include <string.h> // for memset
 
 #ifdef __APPLE__
 #   include <mach/mach.h>

test/test_shared.cpp

@@ -220,7 +220,7 @@ TEST(Shared_CompactingOnTheFly)
     std::string tmp_path = std::string(path)+".tmp";
     Thread writer_thread;
     {
-        SharedGroup sg(path, false, SharedGroup::durability_Full);
+        SharedGroup sg(path, false, SharedGroup::durability_Full, crypt_key());
         // Create table entries
         {
             WriteTransaction wt(sg);
@@ -258,7 +258,7 @@ TEST(Shared_CompactingOnTheFly)
     }
     writer_thread.join();
     {
-        SharedGroup sg2(path, true, SharedGroup::durability_Full);
+        SharedGroup sg2(path, true, SharedGroup::durability_Full, crypt_key());
         {
             sg2.begin_write();
             sg2.commit();