Usermode/ld-acess - Fix dynamic linking quirk (STB_WEAK and R_COPY)

diff --git a/Usermode/Libraries/ld-acess.so_src/elf.c b/Usermode/Libraries/ld-acess.so_src/elf.c
index 0adb2a7..e3109b4 100644 (file)
--- a/Usermode/Libraries/ld-acess.so_src/elf.c
+++ b/Usermode/Libraries/ld-acess.so_src/elf.c
@@ -4,8 +4,10 @@
  *
  * elf.c
  * - ELF32/ELF64 relocation
+ *
+ * TODO: Have GetSymbol() return a symbol "strength" on success. Allows STB_WEAK to be overriden by STB_GLOBAL
  */
-#ifndef DEBUG  // This code is #include'd from the kernel, so DEBUG may already be defined
+#ifndef KERNEL_VERSION
 # define DEBUG 0
 #endif
 
@@ -29,7 +31,8 @@
 
 #define WARNING(f,...) SysDebug("WARN: "f ,## __VA_ARGS__)     // Malformed file
 #define NOTICE(f,...)  SysDebug("NOTICE: "f ,## __VA_ARGS__)   // Missing relocation
-#define TRACE(f,...)   DEBUG_OUT("TRACE:%s:%i "f, __func__, __LINE__ ,## __VA_ARGS__)  // Debugging trace
+//#define TRACE(f,...) DEBUG_OUT("TRACE:%s:%i "f, __func__, __LINE__ ,## __VA_ARGS__)  // Debugging trace
+#define TRACE(f,...)   DEBUG_OUT("TRACE:%s "f, __func__,## __VA_ARGS__)        // Debugging trace
 
 #ifndef DISABLE_ELF64
 # define SUPPORT_ELF64
@@ -234,7 +237,6 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
        const Elf32_Ehdr        *hdr = Base;
        char    *libPath;
        intptr_t        iRealBase = -1;
-       intptr_t        iBaseDiff;
        Elf32_Rel       *rel = NULL;
        Elf32_Rela      *rela = NULL;
        void    *plt = NULL;
@@ -275,10 +277,11 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
        
        // Page Align real base
        iRealBase &= ~0xFFF;
-       TRACE("True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
        
        // Adjust "Real" Base
-       iBaseDiff = (intptr_t)Base - iRealBase;
+       const intptr_t  iBaseDiff = (intptr_t)Base - iRealBase;
+
+       TRACE("True Base = 0x%x, Compiled Base = 0x%x, Difference = 0x%x", Base, iRealBase, iBaseDiff);
 
        // Check if a PT_DYNAMIC segement was found
        if(!dynamicTab) {
@@ -357,17 +360,18 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
                        size_t  newsize;
                        if( ELF32_ST_BIND(sym->st_info) != STB_WEAK )
                        {
-                               TRACE("Sym %i'%s' %p += 0x%x", i, name, sym->st_value, iBaseDiff);
+                               TRACE("Sym %i'%s' = %p (local)", i, name, sym->st_value + iBaseDiff);
                                sym->st_value += iBaseDiff;
                        }
-                       else if( !GetSymbol(name, &newval, &newsize, Base) )
+                       // If GetSymbol doesn't return a strong/global symbol value
+                       else if( GetSymbol(name, &newval, &newsize, Base) != 1 )
                        {
-                               TRACE("Sym %i'%s' %p += 0x%x (Local weak)", i, name, sym->st_value, iBaseDiff);
+                               TRACE("Sym %i'%s' = %p (Local weak)", i, name, sym->st_value + iBaseDiff);
                                sym->st_value += iBaseDiff;
                        }
                        else
                        {
-                               TRACE("Sym %i'%s' %p = %p+0x%x (Extern weak)", i, name, newval, newsize);
+                               TRACE("Sym %i'%s' = %p+0x%x (Extern weak)", i, name, newval, newsize);
                                sym->st_value = (uintptr_t)newval;
                                sym->st_size = newsize;
                        }
@@ -690,14 +694,18 @@ int Elf32GetSymbolInfo(void *Base, const char *Name, void **Addr, size_t *Size,
 
 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 {
-        int    section;
+        int    section, binding;
        TRACE("Elf32GetSymbol(%p,%s,...)", Base, Name);
-       if( Elf32GetSymbolInfo(Base, Name, ret, Size, &section, NULL, NULL) )
+       if( Elf32GetSymbolInfo(Base, Name, ret, Size, &section, &binding, NULL) )
                return 0;
        if( section == SHN_UNDEF ) {
-               TRACE("Elf32GetSymbol: Undefined", *ret, (Size?*Size:0), section);
+               TRACE("Elf32GetSymbol: Undefined %p", *ret, (Size?*Size:0), section);
                return 0;
        }
+       if( binding == STB_WEAK ) {
+               TRACE("Elf32GetSymbol: Weak, return %p+0x%x,section=%i", *ret, (Size?*Size:0), section);
+               return 2;
+       }
        TRACE("Elf32GetSymbol: Found %p+0x%x,section=%i", *ret, (Size?*Size:0), section);
        return 1;
 }

diff --git a/Usermode/Libraries/ld-acess.so_src/loadlib.c b/Usermode/Libraries/ld-acess.so_src/loadlib.c
index dbb7c15..1c750a8 100644 (file)
--- a/Usermode/Libraries/ld-acess.so_src/loadlib.c
+++ b/Usermode/Libraries/ld-acess.so_src/loadlib.c
@@ -4,6 +4,7 @@
 */
 #include "common.h"
 #include <stdint.h>
+#include <stdbool.h>
 #include <acess/sys.h>
 
 #define DEBUG  0
@@ -266,7 +267,8 @@ int GetSymbol(const char *name, void **Value, size_t *Size, void *IgnoreBase)
                        return 1;
                }
        }
-       
+
+       bool have_weak = false; 
        for(int i = 0; i < MAX_LOADED_LIBRARIES && gLoadedLibraries[i].Base != 0; i ++)
        {
                // Allow ignoring the current module
@@ -277,13 +279,25 @@ int GetSymbol(const char *name, void **Value, size_t *Size, void *IgnoreBase)
                
                //SysDebug(" GetSymbol: Trying 0x%x, '%s'",
                //      gLoadedLibraries[i].Base, gLoadedLibraries[i].Name);
-               if(GetSymbolFromBase(gLoadedLibraries[i].Base, name, Value, Size)) {
-                       //SysDebug("GetSymbol: Remote %p - %p", gLoadedLibraries[i].Base, *Value);
-                       return 1;
+               void    *tmpval;
+               size_t  tmpsize;
+               int rv = GetSymbolFromBase(gLoadedLibraries[i].Base, name, &tmpval, &tmpsize);
+               if(rv)
+               {
+                       *Value = tmpval;
+                       *Size = tmpsize;
+                       if( rv == 1 ) {
+                               return 1;
+                       }
+                       have_weak = true;
                }
        }
-       //SysDebug("GetSymbol: None");
-       return 0;
+       if(have_weak) {
+               return 2;
+       }
+       else {
+               return 0;
+       }
 }
 
 /**