try fixing issue number 17 (not done)

CMakeLists.txt

@@ -219,12 +219,6 @@ if(JEMALLOC)
 endif(JEMALLOC)
 
 
-# FS_LIB should resolve to nothing on all other platforms
-# it is only required on win32 -rick
-set(LIBS ${MALLOC_LIB} ${FS_LIB})
-if(NOT WIN32)
-  set(LIBS ${LIBS} uv)
-endif()
 
 if(ANDROID)
   list(APPEND LIBS log)
@@ -256,6 +250,11 @@ if(NOT WIN32)
   add_subdirectory(vendor)
 endif()
 
+set(LIBS ${MALLOC_LIB} ${FS_LIB})
+if(NOT WIN32)
+  set(LIBS ${LIBS} uv)
+endif()
+
 add_subdirectory(crypto)
 add_subdirectory(libutp)
 add_subdirectory(llarp)
@@ -263,7 +262,7 @@ add_subdirectory(libabyss)
 
 if (NOT WIN32)
   add_executable(${ABYSS_EXE} ${ABYSS}/main.cpp)
-  target_link_libraries(${ABYSS_EXE} PUBLIC ${ABYSS_LIB} Threads::Threads)
+  target_link_libraries(${ABYSS_EXE} PUBLIC ${ABYSS_LIB} Threads::Threads ${LIBS})
 elseif(NOT MSVC_VERSION)
   add_executable(${ABYSS_EXE} ${ABYSS}/main.cpp llarp/win32/abyss.rc)
   target_link_libraries(${ABYSS_EXE} PUBLIC ${ABYSS_LIB} ${STATIC_LIB} ws2_32)
@@ -315,7 +314,7 @@ else()
   if(${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
     target_link_directories(${EXE} PRIVATE /usr/local/lib)
   endif()
-  target_link_libraries(${EXE} PUBLIC ${EXE_LIBS})
+  target_link_libraries(${EXE} PUBLIC ${EXE_LIBS} ${LIBS})
 
   if(ANDROID)
     add_library(${ANDROID_LIB} SHARED jni/lokinet_android.cpp)

cmake/unix.cmake

@@ -19,8 +19,11 @@ else()
   message(FATAL_ERROR "Your operating system is not supported yet")
 endif()
 
-set(EXE_LIBS ${STATIC_LIB} cppbackport libutp)
+set(FS_LIB stdc++fs)
+
+set(EXE_LIBS ${STATIC_LIB} libutp)
 
 if(RELEASE_MOTTO)
   add_definitions(-DLLARP_RELEASE_MOTTO="${RELEASE_MOTTO}")
 endif()
+

llarp/CMakeLists.txt

@@ -95,7 +95,7 @@ else()
 endif(WIN32)
 
 add_library(${PLATFORM_LIB} STATIC ${LIB_PLATFORM_SRC})
-target_link_libraries(${PLATFORM_LIB} PUBLIC ${CRYPTOGRAPHY_LIB} ${UTIL_LIB} libutp Threads::Threads)
+target_link_libraries(${PLATFORM_LIB} PUBLIC ${CRYPTOGRAPHY_LIB} ${UTIL_LIB} libutp Threads::Threads ${LIBS})
 
 if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
   if(NON_PC_TARGET)
@@ -241,7 +241,7 @@ endif()
 
 add_library(${STATIC_LIB} STATIC ${LIB_SRC})
 set(LIBS ${LIBS} libutp)
-target_link_libraries(${STATIC_LIB} PUBLIC cxxopts ${ABYSS_LIB} ${PLATFORM_LIB} ${UTIL_LIB} ${CRYPTOGRAPHY_LIB} ${LIBS})
+target_link_libraries(${STATIC_LIB} PUBLIC cxxopts ${ABYSS_LIB} ${PLATFORM_LIB} ${UTIL_LIB} ${CRYPTOGRAPHY_LIB})
 
 if(${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
   target_include_directories(${PLATFORM_LIB} SYSTEM PUBLIC /usr/local/include)

llarp/util/fs.cpp

@@ -1 +1,34 @@
 #include <util/fs.hpp>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <system_error>
+
+namespace llarp
+{
+  namespace util
+  {
+    error_code_t
+    EnsurePrivateFile(fs::path pathname)
+    {
+      auto str = pathname.string();
+      error_code_t ec;
+      if(fs::exists(pathname, ec)) // file exists
+      {
+        fs::permissions(pathname, ~fs::perms::group_all | ~fs::perms::others_all | fs::perms::owner_read | fs::perms::owner_write, ec);
+      }
+      else if(!ec) // file is not there
+      {
+        int fd = ::open(str.c_str(), O_WRONLY | O_CREAT, 0600);
+        int e = errno;
+        if(fd != -1)
+        {
+          ::close(fd);
+        }
+        ec = std::error_code(e, std::generic_category());
+        errno = 0;
+      }
+      return ec;
+    }
+  }
+}

llarp/util/fs.hpp

@@ -8,13 +8,9 @@
 #define PATH_SEP "/"
 #endif
 
-#ifdef _WIN32
 #include <experimental/filesystem>
 namespace fs = std::experimental::filesystem;
-#else
-#include "filesystem.h"
-namespace fs = cpp17::filesystem;
-#endif
+
 
 #ifndef _MSC_VER
 #include <dirent.h>
@@ -24,6 +20,28 @@ namespace llarp
 {
   namespace util
   {
+
+    using error_code_t = std::error_code;
+
+    /// Ensure that a file exists and has correct permissions
+    /// return any error code or success
+    error_code_t
+    EnsurePrivateFile(fs::path pathname);
+
+    /// open a stream to a file and ensure it exists before open
+    /// sets any permissions on creation
+    template<typename T>
+    T OpenFileStream(fs::path pathname)
+    {
+      T stream;
+      if(EnsurePrivateFile(pathname))
+      {
+        std::string f = pathname.string();
+        stream.open(f);
+      }
+      return stream;
+    }
+
     using PathVisitor = std::function< bool(const fs::path &) >;
     using PathIter    = std::function< void(const fs::path &, PathVisitor) >;