Usermode/ld-acess - Cleanup to ELF32 relocation code

diff --git a/Usermode/Libraries/ld-acess.so_src/elf.c b/Usermode/Libraries/ld-acess.so_src/elf.c
index 15e8420..b60c8a8 100644 (file)
--- a/Usermode/Libraries/ld-acess.so_src/elf.c
+++ b/Usermode/Libraries/ld-acess.so_src/elf.c
@@ -204,12 +204,10 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 {
        Elf32_Ehdr      *hdr = Base;
        Elf32_Phdr      *phtab;
-        int    i, j;   // Counters
        char    *libPath;
        intptr_t        iRealBase = -1;
        intptr_t        iBaseDiff;
         int    iSegmentCount;
-//      int    iSymCount;
        Elf32_Rel       *rel = NULL;
        Elf32_Rela      *rela = NULL;
        void    *plt = NULL;
@@ -229,20 +227,24 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
        // Parse Program Header to get Dynamic Table
        phtab = (void*)( (uintptr_t)Base + hdr->phoff );
        iSegmentCount = hdr->phentcount;
-       for(i=0;i<iSegmentCount;i++)
+       for(int i = 0; i < iSegmentCount; i ++)
        {
-               // Determine linked base address
-               if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
-                       iRealBase = phtab[i].VAddr;
-               
-               // Find Dynamic Section
-               if(phtab[i].Type == PT_DYNAMIC) {
-                       if(dynamicTab) {
+               switch(phtab[i].Type)
+               {
+               case PT_LOAD:
+                       // Determine linked base address
+                       if( iRealBase > phtab[i].VAddr)
+                               iRealBase = phtab[i].VAddr;
+                       break;
+               case PT_DYNAMIC:
+                       // Find Dynamic Section
+                       if(!dynamicTab) {
+                               dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
+                       }
+                       else {
                                DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
-                               continue;
                        }
-                       dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
-                       j = i;  // Save Dynamic Table ID
+                       break;
                }
        }
        
@@ -263,7 +265,7 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 
        // Allow writing to read-only segments, just in case they need to be relocated
        // - Will be reversed at the end of the function
-       for( i = 0; i < iSegmentCount; i ++ )
+       for( int i = 0; i < iSegmentCount; i ++ )
        {
                if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
                        uintptr_t       addr = phtab[i].VAddr + iBaseDiff;
@@ -278,7 +280,7 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
        
        // === Get Symbol table and String Table ===
        dynsymtab = NULL;
-       for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
+       for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
        {
                switch(dynamicTab[j].d_tag)
                {
@@ -314,7 +316,7 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 
        // === Parse Relocation Data ===
        DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
-       for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
+       for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
        {
                switch(dynamicTab[j].d_tag)
                {
@@ -398,8 +400,8 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
        {
                Elf32_Word      *ptr;
                DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
-               j = relSz / relEntSz;
-               for( i = 0; i < j; i++ )
+               int max = relSz / relEntSz;
+               for( int i = 0; i < max; i++ )
                {
                        //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
                        ptr = (void*)(iBaseDiff + rel[i].r_offset);
@@ -411,8 +413,8 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
        {
                Elf32_Word      *ptr;
                DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
-               j = relaSz / relaEntSz;
-               for( i = 0; i < j; i++ )
+               int count = relaSz / relaEntSz;
+               for( int i = 0; i < count; i++ )
                {
                        ptr = (void*)(iBaseDiff + rela[i].r_offset);
                        fail |= _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
@@ -427,9 +429,9 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
                if(pltType == DT_REL)
                {
                        Elf32_Rel       *pltRel = plt;
-                       j = pltSz / sizeof(Elf32_Rel);
-                       DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
-                       for(i=0;i<j;i++)
+                       int count = pltSz / sizeof(Elf32_Rel);
+                       DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", count);
+                       for(int i = 0; i < count; i ++)
                        {
                                ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
                                fail |= _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
@@ -438,9 +440,9 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
                else
                {
                        Elf32_Rela      *pltRela = plt;
-                       j = pltSz / sizeof(Elf32_Rela);
-                       DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
-                       for(i=0;i<j;i++)
+                       int count = pltSz / sizeof(Elf32_Rela);
+                       DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", count);
+                       for(int i=0;i<count;i++)
                        {
                                ptr = (void*)(iRealBase + pltRela[i].r_offset);
                                fail |= _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
@@ -449,7 +451,7 @@ void *Elf32Relocate(void *Base, char **envp, const char *Filename)
        }
 
        // Re-set readonly
-       for( i = 0; i < iSegmentCount; i ++ )
+       for( int i = 0; i < iSegmentCount; i ++ )
        {
                // If load and not writable
                if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
@@ -483,11 +485,10 @@ int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
        uintptr_t       iBaseDiff = -1;
        Elf32_Phdr      *phtab;
        Elf32_Dyn       *dynTab = NULL;
-        int    i;
 
        // Locate the tables
        phtab = (void*)( (uintptr_t)Base + hdr->phoff );
-       for( i = 0; i < hdr->phentcount; i ++ )
+       for( int i = 0; i < hdr->phentcount; i ++ )
        {
                if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
                        iBaseDiff = phtab[i].VAddr;
@@ -501,7 +502,7 @@ int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
        }
        iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
        dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
-       for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
+       for( int i = 0; dynTab[i].d_tag != DT_NULL; i++)
        {
                switch(dynTab[i].d_tag)
                {
@@ -545,28 +546,23 @@ int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 //     iSymCount = pBuckets[1];
        pBuckets = &pBuckets[2];
        pChains = &pBuckets[ nbuckets ];
+       assert(pChains);
 
        // Get hash
        iNameHash = ElfHashString(Name);
        iNameHash %= nbuckets;
 
        // Walk Chain
-       i = pBuckets[ iNameHash ];
-       if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
-               *ret = (void*)( (uintptr_t) symtab[ i ].value + iBaseDiff );
-               if(Size)        *Size = symtab[i].size;
-               return 1;
-       }
-       
-       while(pChains[i] != STN_UNDEF)
-       {
-               i = pChains[i];
-               if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
-                       *ret = (void*)( (uintptr_t)symtab[ i ].value + iBaseDiff );
-                       if(Size)        *Size = symtab[i].size;
+       int idx = pBuckets[ iNameHash ];
+       do {
+               Elf32_Sym *sym = &symtab[idx];
+               assert(sym);
+               if(sym->shndx != SHN_UNDEF && strcmp(dynstrtab + sym->nameOfs, Name) == 0) {
+                       *ret = (void*)( (uintptr_t)sym->value + iBaseDiff );
+                       if(Size)        *Size = sym->size;
                        return 1;
                }
-       }
+       } while( (idx = pChains[idx]) != STN_UNDEF && idx != pBuckets[iNameHash] );
        
        return 0;
 }