int fct_lb(inst k, mem memory, registre* reg)
{
int tmp;
uint32_t base = k.i.rs;
uint32_t offset = k.i.imm;
uint32_t addr = reg[base].val + (signed) offset;
uint32_t value;
if (addr<memory->start_mem) ERROR_MSG("La memoire commence en 0x%08x",memory->start_mem);
if (addr>STOP_MEM) ERROR_MSG("La memoire termine en 0x%08x",STOP_MEM);
tmp = find_word(memory, addr, &value);
if (tmp==cmd_unknown)
{ printf("\n");
ERROR_MSG("L'adresse 0x%08x n'est pas allouee", addr);
return cmd_unknown;
}
else {
value = (signed) value;
value = FLIP_ENDIANNESS(value);
if (addr%4==0) reg[k.i.rt].val = value&0x000000ff;
else if (addr%4==1) reg[k.i.rt].val=(value&0x0000ff00)>>8;
else if (addr%4==2) reg[k.i.rt].val=(value&0x00ff0000)>>16;
else if (addr%4==3) reg[k.i.rt].val=(value&0xff000000)>>24;
void print_segment_raw_content(segment* seg) {
int k;
int word =0;
if (seg!=NULL && seg->size._32>0) { /* on vérifie que le segment n'est pas vide */
for(k=0; k<seg->size._32; k+=4) { /* on lit chaque donnée présente dans le segment à afficher */
if(k%16==0) printf("\n 0x%08x ",k); /* affiche l'adresse lue chaque multiple de 16 et retourne à la ligne à la fin d'un octet */
word = *((unsigned int *) (seg->content+k));
FLIP_ENDIANNESS(word);
printf("%08x ", word); /* affiche chaque octet d'un segment */
}
}
}
void print_segment_raw_content(segment* seg) { //Affiche un segment donne
int k;
int word =0;
if (seg!=NULL && seg->size._32>0) {
for(k=0; k<seg->size._32; k+=4) {
if(k%16==0) printf("\n 0x%08x ",k);
word = *((unsigned int *) (seg->content+k));
FLIP_ENDIANNESS(word);
printf("%08x ", word);
}
}
}
/**
* @param fp le fichier elf original
* @param seg le segment a reloger
* @param mem l'ensemble des segments
* @param endianness le boutisme du programme
* @param symtab la table des symbole du programme
* @param symtab_libc la table des symbole de la libc (NULL si inutile)
* @param fp_libc le fichier elf de la libc (NULL si inutile)
* @brief Cette fonction effectue la relocation du segment passe en parametres
* @brief l'ensemble des segments doit deja avoir ete charge en memoire.
*
* VOUS DEVEZ COMPLETER CETTE FONCTION POUR METTRE EN OEUVRE LA RELOCATION !!
*/
void reloc_segment(FILE* fp, segment seg, mem memory,unsigned int endianness,stab* symtable,stab* symtab_libc,FILE* fp_libc) {
byte *ehdr = __elf_get_ehdr( fp );
uint32_t scnsz = 0;
Elf32_Rel *rel = NULL;
char* reloc_name = malloc(strlen(seg.name)+strlen(RELOC_PREFIX_STR)+1);
scntab section_tab;
scntab section_tab_libc;
// on recompose le nom de la section
memcpy(reloc_name,RELOC_PREFIX_STR,strlen(RELOC_PREFIX_STR)+1);
strcat(reloc_name,seg.name);
// on recupere le tableau de relocation et la table des sections
rel = (Elf32_Rel *)elf_extract_scn_by_name( ehdr, fp, reloc_name, &scnsz, NULL );
elf_load_scntab(fp ,32, §ion_tab);
if (symtab_libc!=NULL && fp_libc!=NULL)
elf_load_scntab(fp_libc ,32, §ion_tab_libc);
if (rel != NULL &&seg.content!=NULL && seg.size._32!=0) {
if(verbose>0) {
INFO_MSG("--------------Relocation of %s-------------------\n",seg.name) ;
INFO_MSG("Number of symbol to relocate: %ld\n",scnsz/sizeof(*rel)) ;
}
//------------------------------------------------------
int i=0;
uint sym;
uint type;
uint info;
uint offset;
//display :
if(verbose>0) {
//printf("scnsz=%d\n", scnsz);
//print_scntab(section_tab);
printf("Offset Info Type Sym.Value Sym.Name\n");
while(i<scnsz/sizeof(*rel)) {
info=rel[i].r_info;
offset=rel[i].r_offset;
FLIP_ENDIANNESS(info) ;
FLIP_ENDIANNESS(offset) ;
sym=ELF32_R_SYM(info);
type=ELF32_R_TYPE(info);
if (type>32) {
WARNING_MSG("Unknown type : %d",type);
}
else {
printf("%08X %08X %-14s %08X %s\n",offset,info,MIPS32_REL[type],sym,(*symtable).sym[sym].name);
i++;
}
}
}
i=0;
//------------------------------------------------------
//Reloc :
int A,V,P;
//int segnum;
uint32_t S;
while(i<scnsz/sizeof(*rel)) {
info=rel[i].r_info;
offset=rel[i].r_offset;
FLIP_ENDIANNESS(info) ;
FLIP_ENDIANNESS(offset) ;
sym=ELF32_R_SYM(info);
type=ELF32_R_TYPE(info);
//printf("Relocating symbol %d\n",i );
//segnum=seg_from_scnidx((*symtable).sym[sym].scnidx,(*symtable),memory);
//if(segnum==-1){
// WARNING_MSG("Couldn't resolve scndix correspondance");
// break;
//}
//S=memory->seg[segnum].start._32+(*symtable).sym[sym].addr._32;//a verif
//printf("sym=%d, symbtable size=%d\n", sym,(*symtable).size);
if(addr_from_symnb(sym, (*symtable), memory,&S)==-1) {
WARNING_MSG("Trying to resolve scndix correspondance in libcsymtab");
}
P=seg.start._32+offset;
memRead(P,1,&A);
//printf("Relocation type %s\n",MIPS32_REL[type] );
switch (type) {
case 2:
V=S+A;
//printf("V= %X,S=%X,A=%X,P=%X\n",V,S,A,P);
memWrite(P,1,V);
break;
case 4:
V=(A&0xFC00000)|((((A<<2)|((P&0xF0000000)+S))>>2)&0x3FFFFFF);
//printf("V= %X,S=%X,A=%X,P=%X\n",V,S,A,P);
memWrite(P,1,V);
break;
case 5:
;
uint nexttype=rel[i+1].r_info;
uint nextoffset=rel[i+1].r_offset;
FLIP_ENDIANNESS(nexttype);
FLIP_ENDIANNESS(nextoffset);
nexttype=ELF32_R_TYPE(nexttype);
if(nexttype!=6) {
WARNING_MSG("R_MIPS_HI16 not followed by R_MIIPS_LO16 : %s",MIPS32_REL[nexttype]);
}
else {
int P2=seg.start._32+nextoffset,A2;
memRead(P2,1,&A2);
int AHL;
AHL=(A<<16)+(short)(A2);
//printf("A2=%X short A2=%X\n",A2, (short)A2 );
//printf("AHL : %X\n",AHL );
//printf("Total=%X AHL+S=%X, (AHL+S)&0xFFFF=%X, diff=%X\n",((AHL+S-(short)(AHL+S))>>16),AHL+S,(AHL+S)&0xFFFF,AHL+S-(short)AHL+S) ;
V=(A & 0xFFFF0000)|( ((AHL+S-(short)(AHL+S))>>16) &0xFFFF);
//printf("V= %X,S=%X,A=%X,A2=%X,P=%X,P2=%X, AHL=%X\n",V,S,A,A2,P,P2,AHL);
memWrite(P,1,V);
}
break;
case 6:
;
int previoustype=rel[i-1].r_info;
int previousoffset=rel[i-1].r_offset;
FLIP_ENDIANNESS(previoustype);
FLIP_ENDIANNESS(previousoffset);
previoustype=ELF32_R_TYPE(previoustype);
if(previoustype!=5) {
WARNING_MSG("R_MIPS_LO16 not preceded by R_MIPS_HI16 : %s",MIPS32_REL[previoustype]);
}
else {
int32_t P2=seg.start._32+previousoffset,A2;
memRead(P2,1,&A2);
int32_t AHL=(A2<<16)+(short)(A);
V=(A&0xFFFF0000)|((short)(AHL+S)&0xFFFF);
//printf("V= %X,S=%X,A=%X,P=%X\n",V,S,A,P);
memWrite(P,1,V);
}
break;
default:
if (type>32) {
WARNING_MSG("Unknown type : %d, relocation impossible for element %d",type,i);
}
else {
WARNING_MSG("Unknown type : %s(code : %d), relocation impossible for element %d",MIPS32_REL[type],type,i);
}
break;
}
i++;
}
//------------------------------------------------------
}
del_scntab(section_tab);
free( rel );
free( reloc_name );
free( ehdr );
}
