ldso: Rework global scope handling and symbol lookup mechanism

Global symbol scope is implemented as a linked list of
local scope, that dynamically grows and shrinks when dlopen/
dlclose are called. Each local scope is implemented as an array
of pointer to struct elf_resolve.
This will help to detect conflict when LD_TRACE_PRELINKING option
will be implemented.

Signed-off-by: Filippo Arcidiacono <filippo.arcidiacono@st.com>
Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

4 files changed, 20 insertions, 7 deletions

diff --git a/ldso/include/dl-defs.h b/ldso/include/dl-defs.h
index 2d6303cfe..cbbaa3cea 100644
--- a/ldso/include/dl-defs.h
+++ b/ldso/include/dl-defs.h
@@ -225,7 +225,7 @@ typedef struct {
 /* Similar to DL_LOADADDR_UNMAP, but used for libraries that have been
    dlopen()ed successfully, when they're dlclose()d.  */
 #ifndef DL_LIB_UNMAP
-# define DL_LIB_UNMAP(LIB, LEN) (DL_LOADADDR_UNMAP ((LIB)->loadaddr, (LEN)))
+# define DL_LIB_UNMAP(LIB, LEN) (DL_LOADADDR_UNMAP ((LIB)->mapaddr, (LEN)))
 #endif
 
 /* Define this to verify that a library named LIBNAME, whose ELF
diff --git a/ldso/include/dl-elf.h b/ldso/include/dl-elf.h
index dc4af7bce..3e8586444 100644
--- a/ldso/include/dl-elf.h
+++ b/ldso/include/dl-elf.h
@@ -15,6 +15,7 @@
 /* Forward declarations for stuff defined in ld_hash.h */
 struct dyn_elf;
 struct elf_resolve;
+struct r_scope_elem;
 
 #include <dl-defs.h>
 #ifdef __LDSO_CACHE_SUPPORT__
@@ -30,7 +31,7 @@ static __inline__ void _dl_unmap_cache(void) { }
 extern void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
 	unsigned long rel_addr, unsigned long rel_size);
 extern int _dl_parse_relocation_information(struct dyn_elf *rpnt,
-	unsigned long rel_addr, unsigned long rel_size);
+	struct r_scope_elem *scope, unsigned long rel_addr, unsigned long rel_size);
 extern struct elf_resolve * _dl_load_shared_library(int secure,
 	struct dyn_elf **rpnt, struct elf_resolve *tpnt, char *full_libname,
 	int trace_loaded_objects);
@@ -39,7 +40,7 @@ extern struct elf_resolve * _dl_load_elf_shared_library(int secure,
 extern struct elf_resolve *_dl_check_if_named_library_is_loaded(const char *full_libname,
 	int trace_loaded_objects);
 extern int _dl_linux_resolve(void);
-extern int _dl_fixup(struct dyn_elf *rpnt, int flag);
+extern int _dl_fixup(struct dyn_elf *rpnt, struct r_scope_elem *scope, int flag);
 extern void _dl_protect_relro (struct elf_resolve *l);
 
 /*
diff --git a/ldso/include/dl-hash.h b/ldso/include/dl-hash.h
index edef9d81b..f47384c31 100644
--- a/ldso/include/dl-hash.h
+++ b/ldso/include/dl-hash.h
@@ -25,6 +25,15 @@ struct dyn_elf {
   struct dyn_elf * prev;
 };
 
+
+/* Structure to describe a single list of scope elements.  The lookup
+   functions get passed an array of pointers to such structures.  */
+struct r_scope_elem {
+  struct elf_resolve **r_list; /* Array of maps for the scope.  */
+  unsigned int r_nlist;        /* Number of entries in the scope.  */
+  struct r_scope_elem *next;
+};
+
 struct elf_resolve {
   /* These entries must be in this order to be compatible with the interface used
      by gdb to obtain the list of symbols. */
@@ -65,7 +74,8 @@ struct elf_resolve {
   ElfW(Addr) l_entry;
 #endif
   enum {elf_lib, elf_executable,program_interpreter, loaded_file} libtype;
-  struct dyn_elf * symbol_scope;
+  /* This is the local scope of the shared object */
+  struct r_scope_elem symbol_scope;
   unsigned short usage_count;
   unsigned short int init_flag;
   unsigned long rtld_flags; /* RTLD_GLOBAL, RTLD_NOW etc. */
@@ -132,6 +142,7 @@ struct elf_resolve {
 #define INIT_FUNCS_CALLED   0x000004
 #define FINI_FUNCS_CALLED   0x000008
 #define DL_OPENED	    0x000010
+#define DL_RESERVED	    0x000020
 
 extern struct dyn_elf     * _dl_symbol_tables;
 extern struct elf_resolve * _dl_loaded_modules;
@@ -145,15 +156,15 @@ extern struct elf_resolve * _dl_add_elf_hash_table(const char * libname,
 #if !((defined(USE_TLS) && USE_TLS) || defined __FDPIC__)
 # define _dl_lookup_hash(n, r, m, c, t) _dl_lookup_hash(n, r, m, c)
 #endif
-extern char *_dl_lookup_hash(const char *name, struct dyn_elf *rpnt,
+extern char *_dl_lookup_hash(const char *name, struct r_scope_elem *scope,
 	struct elf_resolve *mytpnt, int type_class,
 	struct elf_resolve **tpntp);
 
-static __always_inline char *_dl_find_hash(const char *name, struct dyn_elf *rpnt,
+static __always_inline char *_dl_find_hash(const char *name, struct r_scope_elem *scope,
 					struct elf_resolve *mytpnt, int type_class,
 					struct elf_resolve **tpntp)
 {
-	return _dl_lookup_hash(name, rpnt, mytpnt, type_class, tpntp);
+	return _dl_lookup_hash(name, scope, mytpnt, type_class, tpntp);
 }
 
 extern int _dl_linux_dynamic_link(void);
diff --git a/ldso/include/ldso.h b/ldso/include/ldso.h
index 120889216..536f7d266 100644
--- a/ldso/include/ldso.h
+++ b/ldso/include/ldso.h
@@ -27,6 +27,7 @@
 /* Pull in compiler and arch stuff */
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stddef.h> /* for ptrdiff_t */
 #define _FCNTL_H
 #include <bits/fcntl.h>
 #include <bits/wordsize.h>