Add "get executable's path" function

src/file_utils.cpp

@@ -98,3 +98,10 @@ bool dir_exists(const std::string& path)
     struct stat s;
     return !stat(path.c_str(), &s) && S_ISDIR(s.st_mode);
 }
+
+std::string get_exe_path()
+{
+    char result[PATH_MAX] {};
+    ssize_t count = readlink("/proc/self/exe", result, PATH_MAX);
+    return std::string(result, (count > 0) ? count : 0);
+}

src/file_utils.h

@@ -15,3 +15,4 @@ bool find_folder(const std::string& root, const std::string& prefix, std::string
 std::vector<std::string> ls(const char* root, const char* prefix = nullptr, LS_FLAGS flags = LS_DIRS);
 bool file_exists(const std::string& path);
 bool dir_exists(const std::string& path);
+std::string get_exe_path();