4 files changed, 114 insertions, 15 deletions

diff --git a/src/fs.cpp b/src/fs.cpp
index 570ed3e2ee..e7d06e45ab 100644
--- a/src/fs.cpp
+++ b/src/fs.cpp
@@ -1,5 +1,12 @@
 #include <fs.h>
 
+#ifndef WIN32
+#include <fcntl.h>
+#else
+#include <codecvt>
+#include <windows.h>
+#endif
+
 namespace fsbridge {
 
 FILE *fopen(const fs::path& p, const char *mode)
@@ -12,4 +19,82 @@ FILE *freopen(const fs::path& p, const char *mode, FILE *stream)
     return ::freopen(p.string().c_str(), mode, stream);
 }
 
+#ifndef WIN32
+
+static std::string GetErrorReason() {
+    return std::strerror(errno);
+}
+
+FileLock::FileLock(const fs::path& file)
+{
+    fd = open(file.string().c_str(), O_RDWR);
+    if (fd == -1) {
+        reason = GetErrorReason();
+    }
+}
+
+FileLock::~FileLock()
+{
+    if (fd != -1) {
+        close(fd);
+    }
+}
+
+bool FileLock::TryLock()
+{
+    if (fd == -1) {
+        return false;
+    }
+    struct flock lock;
+    lock.l_type = F_WRLCK;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = 0;
+    lock.l_len = 0;
+    if (fcntl(fd, F_SETLK, &lock) == -1) {
+        reason = GetErrorReason();
+        return false;
+    }
+    return true;
+}
+#else
+
+static std::string GetErrorReason() {
+    wchar_t* err;
+    FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+        nullptr, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), reinterpret_cast<WCHAR*>(&err), 0, nullptr);
+    std::wstring err_str(err);
+    LocalFree(err);
+    return std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>>().to_bytes(err_str);
+}
+
+FileLock::FileLock(const fs::path& file)
+{
+    hFile = CreateFileW(file.wstring().c_str(),  GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
+    if (hFile == INVALID_HANDLE_VALUE) {
+        reason = GetErrorReason();
+    }
+}
+
+FileLock::~FileLock()
+{
+    if (hFile != INVALID_HANDLE_VALUE) {
+        CloseHandle(hFile);
+    }
+}
+
+bool FileLock::TryLock()
+{
+    if (hFile == INVALID_HANDLE_VALUE) {
+        return false;
+    }
+    _OVERLAPPED overlapped = {0};
+    if (!LockFileEx(hFile, LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY, 0, 0, 0, &overlapped)) {
+        reason = GetErrorReason();
+        return false;
+    }
+    return true;
+}
+#endif
+
 } // fsbridge
diff --git a/src/fs.h b/src/fs.h
index abb4be254b..e3ff51604d 100644
--- a/src/fs.h
+++ b/src/fs.h
@@ -19,6 +19,26 @@ namespace fs = boost::filesystem;
 namespace fsbridge {
     FILE *fopen(const fs::path& p, const char *mode);
     FILE *freopen(const fs::path& p, const char *mode, FILE *stream);
+
+    class FileLock
+    {
+    public:
+        FileLock() = delete;
+        FileLock(const FileLock&) = delete;
+        FileLock(FileLock&&) = delete;
+        explicit FileLock(const fs::path& file);
+        ~FileLock();
+        bool TryLock();
+        std::string GetReason() { return reason; }
+
+    private:
+        std::string reason;
+#ifndef WIN32
+        int fd = -1;
+#else
+        void* hFile = (void*)-1; // INVALID_HANDLE_VALUE
+#endif
+    };
 };
 
 #endif // BITCOIN_FS_H
diff --git a/src/init.cpp b/src/init.cpp
index 2131a6adc0..bd330459f6 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -51,13 +51,13 @@
 
 #ifndef WIN32
 #include <signal.h>
+#include <sys/stat.h>
 #endif
 
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/replace.hpp>
 #include <boost/algorithm/string/split.hpp>
 #include <boost/bind.hpp>
-#include <boost/interprocess/sync/file_lock.hpp>
 #include <boost/thread.hpp>
 #include <openssl/crypto.h>
 
diff --git a/src/util.cpp b/src/util.cpp
index 1aab85264f..55b09dcff8 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -71,7 +71,6 @@
 #include <malloc.h>
 #endif
 
-#include <boost/interprocess/sync/file_lock.hpp>
 #include <boost/thread.hpp>
 #include <openssl/crypto.h>
 #include <openssl/rand.h>
@@ -139,7 +138,7 @@ instance_of_cinit;
  * cleans them up and thus automatically unlocks them, or ReleaseDirectoryLocks
  * is called.
  */
-static std::map<std::string, std::unique_ptr<boost::interprocess::file_lock>> dir_locks;
+static std::map<std::string, std::unique_ptr<fsbridge::FileLock>> dir_locks;
 /** Mutex to protect dir_locks. */
 static std::mutex cs_dir_locks;
 
@@ -156,18 +155,13 @@ bool LockDirectory(const fs::path& directory, const std::string lockfile_name, b
     // Create empty lock file if it doesn't exist.
     FILE* file = fsbridge::fopen(pathLockFile, "a");
     if (file) fclose(file);
-
-    try {
-        auto lock = MakeUnique<boost::interprocess::file_lock>(pathLockFile.string().c_str());
-        if (!lock->try_lock()) {
-            return false;
-        }
-        if (!probe_only) {
-            // Lock successful and we're not just probing, put it into the map
-            dir_locks.emplace(pathLockFile.string(), std::move(lock));
-        }
-    } catch (const boost::interprocess::interprocess_exception& e) {
-        return error("Error while attempting to lock directory %s: %s", directory.string(), e.what());
+    auto lock = MakeUnique<fsbridge::FileLock>(pathLockFile);
+    if (!lock->TryLock()) {
+        return error("Error while attempting to lock directory %s: %s", directory.string(), lock->GetReason());
+    }
+    if (!probe_only) {
+        // Lock successful and we're not just probing, put it into the map
+        dir_locks.emplace(pathLockFile.string(), std::move(lock));
     }
     return true;
 }