libdl: Add object file dependencies to track references

Tracking references lets us manage when an object file can be
unloaded. If an object file has references to it, it cannot be
unloaded.

Modules that depend on each other cannot be unloaded.

Updates #3605

1 files changed, 25 insertions, 0 deletions

diff --git a/cpukit/include/rtems/rtl/rtl.h b/cpukit/include/rtems/rtl/rtl.h
index e30dba90ef..398ac2cd3f 100644
--- a/cpukit/include/rtems/rtl/rtl.h
+++ b/cpukit/include/rtems/rtl/rtl.h
@@ -28,6 +28,7 @@
 #include <rtems/rtl/rtl-obj.h>
 #include <rtems/rtl/rtl-obj-cache.h>
 #include <rtems/rtl/rtl-obj-comp.h>
+#include <rtems/rtl/rtl-sym.h>
 #include <rtems/rtl/rtl-unresolved.h>
 
 #ifdef __cplusplus
@@ -71,6 +72,11 @@ extern "C" {
 #define RTEMS_RTL_UNRESOLVED_BLOCK_SIZE (64)
 
 /**
+ * The number of dependency record per block in the dependency table.
+ */
+#define RTEMS_RTL_DEPENDENCY_BLOCK_SIZE (16)
+
+/**
  * The global debugger interface variable.
  */
 extern struct r_debug _rtld_debug;
@@ -173,6 +179,16 @@ void rtems_rtl_obj_decompress (rtems_rtl_obj_comp** decomp,
                                off_t                offset);
 
 /**
+ * Update the mask in the object files. You can clear flags and then set
+ * flags. A zero (0) does not clear or set the flags. This is global to all
+ * object files that are laoded.
+ *
+ * @param clear The flag's clear mask, a 0 does not clear any flags.
+ * @param set The flag's set mask, a 0 does not set any flags.
+ */
+void rtems_rtl_obj_update_flags (uint32_t clear, uint32_t set);
+
+/**
  * Lock the Run-time Linker.
  *
  * @return rtems_rtl_data* The RTL data after being locked.
@@ -207,6 +223,15 @@ rtems_rtl_obj* rtems_rtl_check_handle (void* handle);
 rtems_rtl_obj* rtems_rtl_find_obj (const char* name);
 
 /**
+ * Find the object file a symbol is exported from.
+ *
+ * @param sym The symbol to search with.
+ * @retval NULL No object file found.
+ * @return rtems_rtl_obj* Reference to the symbol.
+ */
+rtems_rtl_obj* rtems_rtl_find_obj_with_symbol (const rtems_rtl_obj_sym* sym);
+
+/**
  * Load an object file into memory relocating it. It will not be resolved
  * against other symbols in other object files or the base image.
  *