lib: utils: Don't use hard-coded path constants

This replaces the package path constant with a runtime library path
lookup. The package path is taken to be the parent directory of the
library directory.

When boost >= 1.61 is not available, this maintains the current behavior
of using CMake to set path contants.

Runtime path determination is preferable for making a relocatable
library so that it is not necessary to do string substitution on
relocated binaries (as with, for example, building a conda package).

2 files changed, 30 insertions, 2 deletions

diff --git a/host/include/uhd/utils/paths.hpp b/host/include/uhd/utils/paths.hpp
index 035a4943d..e5b451542 100644
--- a/host/include/uhd/utils/paths.hpp
+++ b/host/include/uhd/utils/paths.hpp
@@ -23,6 +23,9 @@ UHD_API std::string get_tmp_path(void);
 //! Get a string representing the system's appdata directory
 UHD_API std::string get_app_path(void);
 
+//! Get a string representing the system's library directory
+UHD_API std::string get_lib_path(void);
+
 //! Get a string representing the system's pkg directory
 UHD_API std::string get_pkg_path(void);
 
diff --git a/host/lib/utils/paths.cpp b/host/lib/utils/paths.cpp
index 8fb7a773d..aecdbae80 100644
--- a/host/lib/utils/paths.cpp
+++ b/host/lib/utils/paths.cpp
@@ -11,6 +11,11 @@
 #include <uhdlib/utils/paths.hpp>
 #include <boost/algorithm/string.hpp>
 #include <boost/bind.hpp>
+#include <boost/version.hpp>
+#include <functional>
+#if BOOST_VERSION >= 106100
+#    include <boost/dll/runtime_symbol_info.hpp>
+#endif
 #include <boost/filesystem.hpp>
 #include <boost/format.hpp>
 #include <boost/regex.hpp>
@@ -185,11 +190,32 @@ std::string uhd::get_app_path(void)
     return uhd::get_tmp_path();
 }
 
+#if BOOST_VERSION >= 106100
+std::string uhd::get_pkg_path(void)
+{
+    fs::path pkg_path = fs::path(uhd::get_lib_path()).parent_path().lexically_normal();
+    return get_env_var("UHD_PKG_PATH", pkg_path.string());
+}
+
+std::string uhd::get_lib_path(void)
+{
+    fs::path runtime_libfile_path = boost::dll::this_line_location();
+    return runtime_libfile_path.remove_filename().string();
+}
+#else
 std::string uhd::get_pkg_path(void)
 {
     return get_env_var("UHD_PKG_PATH", UHD_PKG_PATH);
 }
 
+std::string uhd::get_lib_path(void)
+{
+    fs::path lib_path = fs::path(uhd::get_pkg_path()) / UHD_LIB_DIR;
+    return lib_path.string();
+}
+#endif
+
+
 std::vector<fs::path> uhd::get_module_paths(void)
 {
     std::vector<fs::path> paths;
@@ -390,8 +416,7 @@ std::string uhd::find_image_path(
 
 std::string uhd::find_utility(const std::string& name)
 {
-    return fs::path(fs::path(uhd::get_pkg_path()) / UHD_LIB_DIR / "uhd" / "utils" / name)
-        .string();
+    return fs::path(fs::path(uhd::get_lib_path()) / "uhd" / "utils" / name).string();
 }
 
 std::string uhd::print_utility_error(const std::string& name, const std::string& args)