3 * ELF Executable Loader Code
\r
10 #define DEBUG_WARN 1
\r
12 // === PROTOTYPES ===
\r
13 tBinary *Elf_Load(int fp);
\r
14 int Elf_Relocate(void *Base);
\r
15 int Elf_GetSymbol(void *Base, const char *Name, Uint *ret);
\r
16 int Elf_Int_DoRelocate(Uint r_info, Uint32 *ptr, Uint32 addend, Elf32_Sym *symtab, Uint base);
\r
17 Uint Elf_Int_HashString(const char *str);
\r
20 tBinaryType gELF_Info = {
\r
22 0x464C457F, 0xFFFFFFFF, // '\x7FELF'
\r
24 Elf_Load, Elf_Relocate, Elf_GetSymbol
\r
28 tBinary *Elf_Load(int fp)
\r
40 VFS_Read(fp, sizeof(hdr), &hdr);
\r
42 // Check the file type
\r
43 if(hdr.ident[0] != 0x7F || hdr.ident[1] != 'E' || hdr.ident[2] != 'L' || hdr.ident[3] != 'F') {
\r
44 Warning("Non-ELF File was passed to the ELF loader\n");
\r
49 // Check for a program header
\r
50 if(hdr.phoff == 0) {
\r
52 Warning("ELF File does not contain a program header\n");
\r
58 // Read Program Header Table
\r
59 phtab = malloc( sizeof(Elf32_Phdr) * hdr.phentcount );
\r
64 LOG("hdr.phoff = 0x%08x", hdr.phoff);
\r
65 VFS_Seek(fp, hdr.phoff, SEEK_SET);
\r
66 VFS_Read(fp, sizeof(Elf32_Phdr)*hdr.phentcount, phtab);
\r
70 LOG("hdr.phentcount = %i", hdr.phentcount);
\r
71 for( i = 0; i < hdr.phentcount; i++ )
\r
73 // Ignore Non-LOAD types
\r
74 if(phtab[i].Type != PT_LOAD)
\r
76 iPageCount += ((phtab[i].VAddr&0xFFF) + phtab[i].MemSize + 0xFFF) >> 12;
\r
77 LOG("phtab[%i] = {VAddr:0x%x, MemSize:0x%x}", i, phtab[i].VAddr, phtab[i].MemSize);
\r
80 LOG("iPageCount = %i", iPageCount);
\r
82 // Allocate Information Structure
\r
83 ret = malloc( sizeof(tBinary) + sizeof(tBinaryPage)*iPageCount );
\r
85 ret->Entry = hdr.entrypoint;
\r
86 ret->Base = -1; // Set Base to maximum value
\r
87 ret->NumPages = iPageCount;
\r
88 ret->Interpreter = NULL;
\r
92 for( i = 0; i < hdr.phentcount; i++ )
\r
95 //LOG("phtab[%i].Type = 0x%x", i, phtab[i].Type);
\r
96 LOG("phtab[%i] = {", i);
\r
97 LOG(" .Type = 0x%08x", phtab[i].Type);
\r
98 LOG(" .Offset = 0x%08x", phtab[i].Offset);
\r
99 LOG(" .VAddr = 0x%08x", phtab[i].VAddr);
\r
100 LOG(" .PAddr = 0x%08x", phtab[i].PAddr);
\r
101 LOG(" .FileSize = 0x%08x", phtab[i].FileSize);
\r
102 LOG(" .MemSize = 0x%08x", phtab[i].MemSize);
\r
103 LOG(" .Flags = 0x%08x", phtab[i].Flags);
\r
104 LOG(" .Align = 0x%08x", phtab[i].Align);
\r
106 // Get Interpreter Name
\r
107 if( phtab[i].Type == PT_INTERP )
\r
110 if(ret->Interpreter) continue;
\r
111 tmp = malloc(phtab[i].FileSize);
\r
112 VFS_Seek(fp, phtab[i].Offset, 1);
\r
113 VFS_Read(fp, phtab[i].FileSize, tmp);
\r
114 ret->Interpreter = Binary_RegInterp(tmp);
\r
115 LOG("Interpreter '%s'", tmp);
\r
119 // Ignore non-LOAD types
\r
120 if(phtab[i].Type != PT_LOAD) continue;
\r
123 if(phtab[i].VAddr < ret->Base) ret->Base = phtab[i].VAddr;
\r
125 LOG("phtab[%i] = {VAddr:0x%x,Offset:0x%x,FileSize:0x%x}",
\r
126 i, phtab[i].VAddr, phtab[i].Offset, phtab[i].FileSize);
\r
128 //if( (phtab[i].FileSize & 0xFFF) < 0x1000 - (phtab[i].VAddr & 0xFFF) )
\r
129 // lastSize = phtab[i].FileSize;
\r
131 lastSize = (phtab[i].FileSize & 0xFFF) + (phtab[i].VAddr & 0xFFF);
\r
132 //lastSize &= 0xFFF;
\r
134 //LOG("lastSize = 0x%x", lastSize);
\r
136 lastSize = phtab[i].FileSize;
\r
139 count = ( (phtab[i].VAddr&0xFFF) + phtab[i].FileSize + 0xFFF) >> 12;
\r
140 for( k = 0; k < count; k ++ )
\r
142 ret->Pages[j+k].Virtual = phtab[i].VAddr + (k<<12);
\r
143 ret->Pages[j+k].Physical = phtab[i].Offset + (k<<12); // Store the offset in the physical address
\r
145 ret->Pages[j+k].Physical -= ret->Pages[j+k].Virtual&0xFFF;
\r
146 ret->Pages[j+k].Virtual &= ~0xFFF;
\r
149 ret->Pages[j+k].Size = lastSize; // Byte count in page
\r
151 ret->Pages[j+k].Size = 4096 - (phtab[i].VAddr&0xFFF);
\r
153 ret->Pages[j+k].Size = 4096;
\r
154 LOG("ret->Pages[%i].Size = 0x%x", j+k, ret->Pages[j+k].Size);
\r
155 ret->Pages[j+k].Flags = 0;
\r
156 lastSize -= ret->Pages[j+k].Size;
\r
158 count = (phtab[i].MemSize + 0xFFF) >> 12;
\r
161 ret->Pages[j+k].Virtual = phtab[i].VAddr + (k<<12);
\r
162 ret->Pages[j+k].Physical = -1; // -1 = Fill with zeros
\r
163 if(k != 0) ret->Pages[j+k].Virtual &= ~0xFFF;
\r
164 if(k == count-1 && (phtab[i].MemSize & 0xFFF))
\r
165 ret->Pages[j+k].Size = phtab[i].MemSize & 0xFFF; // Byte count in page
\r
167 ret->Pages[j+k].Size = 4096;
\r
168 ret->Pages[j+k].Flags = 0;
\r
169 LOG("%i - 0x%x => 0x%x - 0x%x", j+k,
\r
170 ret->Pages[j+k].Physical, ret->Pages[j+k].Virtual, ret->Pages[j+k].Size);
\r
176 LOG("Cleaning up overlaps");
\r
177 // Clear up Overlaps
\r
186 tmpRgns = malloc(sizeof(*tmpRgns)*count);
\r
188 for(i=0;i<count;i++) {
\r
189 tmpRgns[i].V = ret->Pages[i].Virtual;
\r
190 tmpRgns[i].P = ret->Pages[i].Physical;
\r
191 tmpRgns[i].S = ret->Pages[i].Size;
\r
192 tmpRgns[i].F = ret->Pages[i].Flags;
\r
195 for(i=1,j=0; i < count; i++)
\r
197 if( tmpRgns[j].F == tmpRgns[i].F
\r
198 && tmpRgns[j].V + tmpRgns[j].S == tmpRgns[i].V
\r
199 && ((tmpRgns[j].P == -1 && tmpRgns[i].P == -1)
\r
200 || (tmpRgns[j].P + tmpRgns[j].S == tmpRgns[i].P)) )
\r
202 tmpRgns[j].S += tmpRgns[i].S;
\r
205 tmpRgns[j].V = tmpRgns[i].V;
\r
206 tmpRgns[j].P = tmpRgns[i].P;
\r
207 tmpRgns[j].F = tmpRgns[i].F;
\r
208 tmpRgns[j].S = tmpRgns[i].S;
\r
214 for(i=0;i<count;i++) {
\r
215 //LogF(" Elf_Load: %i - 0x%x => 0x%x - 0x%x\n", i, tmpRgns[i].P, tmpRgns[i].V, tmpRgns[i].S);
\r
216 tmpRgns[i].S += tmpRgns[i].V & 0xFFF;
\r
217 if(tmpRgns[i].P != -1) tmpRgns[i].P -= tmpRgns[i].V & 0xFFF;
\r
218 tmpRgns[i].V &= ~0xFFF;
\r
219 j += (tmpRgns[i].S + 0xFFF) >> 12;
\r
220 //LogF(" Elf_Load: %i - 0x%x => 0x%x - 0x%x\n", i, tmpRgns[i].P, tmpRgns[i].V, tmpRgns[i].S);
\r
223 ret = realloc( ret, sizeof(tBinary) + 3*sizeof(Uint)*j );
\r
225 Warning("BIN", "ElfLoad: Unable to reallocate return structure");
\r
231 for(i=0;i<count;i++) {
\r
232 for( j = 0; j < (tmpRgns[i].S + 0xFFF) >> 12; j++,k++ ) {
\r
233 ret->Pages[k].Flags = tmpRgns[i].F;
\r
234 ret->Pages[k].Virtual = tmpRgns[i].V + (j<<12);
\r
235 if(tmpRgns[i].P != -1) {
\r
236 ret->Pages[k].Physical = tmpRgns[i].P + (j<<12);
\r
238 ret->Pages[k].Physical = -1;
\r
239 ret->Pages[k].Size = tmpRgns[i].S - (j << 12);
\r
240 // Clamp to page size
\r
241 if(ret->Pages[k].Size > 0x1000) ret->Pages[k].Size = 0x1000;
\r
256 // --- ELF RELOCATION ---
\r
257 // Taken from 'ld-acess.so'
\r
259 \fn int Elf_Relocate(void *Base)
\r
260 \brief Relocates a loaded ELF Executable
\r
262 int Elf_Relocate(void *Base)
\r
264 Elf32_Ehdr *hdr = Base;
\r
266 int i, j; // Counters
\r
268 Uint iRealBase = -1;
\r
272 Elf32_Rel *rel = NULL;
\r
273 Elf32_Rela *rela = NULL;
\r
274 Uint32 *pltgot = NULL;
\r
277 int relSz=0, relEntSz=8;
\r
278 int relaSz=0, relaEntSz=8;
\r
279 int pltSz=0, pltType=0;
\r
280 Elf32_Dyn *dynamicTab = NULL; // Dynamic Table Pointer
\r
281 char *dynstrtab = NULL; // .dynamic String Table
\r
282 Elf32_Sym *dynsymtab = NULL;
\r
285 ENTER("pBase", Base);
\r
287 // Parse Program Header to get Dynamic Table
\r
288 phtab = (void *)( (tVAddr)Base + hdr->phoff );
\r
289 iSegmentCount = hdr->phentcount;
\r
290 for(i = 0; i < iSegmentCount; i ++ )
\r
292 // Determine linked base address
\r
293 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
\r
294 iRealBase = phtab[i].VAddr;
\r
296 // Find Dynamic Section
\r
297 if(phtab[i].Type == PT_DYNAMIC) {
\r
299 Log_Warning("ELF", "Elf_Relocate - Multiple PT_DYNAMIC segments\n");
\r
302 dynamicTab = (void *) (tVAddr) phtab[i].VAddr;
\r
303 j = i; // Save Dynamic Table ID
\r
308 // Check if a PT_DYNAMIC segement was found
\r
310 Log_Warning("ELF", "Elf_Relocate: No PT_DYNAMIC segment in image, returning\n");
\r
311 LEAVE('x', hdr->entrypoint);
\r
312 return hdr->entrypoint;
\r
315 // Page Align real base
\r
316 iRealBase &= ~0xFFF;
\r
318 // Adjust "Real" Base
\r
319 iBaseDiff = (Uint)Base - iRealBase;
\r
320 // Adjust Dynamic Table
\r
321 dynamicTab = (void *) ((Uint)dynamicTab + iBaseDiff);
\r
323 // === Get Symbol table and String Table ===
\r
324 for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
\r
326 switch(dynamicTab[j].d_tag)
\r
328 // --- Symbol Table ---
\r
330 dynamicTab[j].d_val += iBaseDiff;
\r
331 dynsymtab = (void*) (tVAddr) dynamicTab[j].d_val;
\r
332 hdr->misc.SymTable = dynamicTab[j].d_val; // Saved in unused bytes of ident
\r
335 // --- String Table ---
\r
337 dynamicTab[j].d_val += iBaseDiff;
\r
338 dynstrtab = (void*) (tVAddr) dynamicTab[j].d_val;
\r
341 // --- Hash Table --
\r
343 dynamicTab[j].d_val += iBaseDiff;
\r
344 iSymCount = ((Uint*)((tVAddr)dynamicTab[j].d_val))[1];
\r
345 hdr->misc.HashTable = dynamicTab[j].d_val; // Saved in unused bytes of ident
\r
351 // Alter Symbols to true base
\r
352 for(i = 0; i < iSymCount; i ++)
\r
354 dynsymtab[i].value += iBaseDiff;
\r
355 dynsymtab[i].nameOfs += (Uint)dynstrtab;
\r
356 //LOG("Sym '%s' = 0x%x (relocated)\n", dynsymtab[i].name, dynsymtab[i].value);
\r
359 // === Add to loaded list (can be imported now) ===
\r
360 //Binary_AddLoaded( (Uint)Base );
\r
362 // === Parse Relocation Data ===
\r
363 for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
\r
365 switch(dynamicTab[j].d_tag)
\r
367 // --- Shared Library Name ---
\r
369 LOG(".so Name '%s'\n", dynstrtab+dynamicTab[j].d_val);
\r
371 // --- Needed Library ---
\r
373 libPath = dynstrtab + dynamicTab[j].d_val;
\r
374 Log_Notice("ELF", "%p - Required Library '%s' (Ignored in kernel mode)\n", Base, libPath);
\r
377 case DT_PLTGOT: pltgot = (void*)(iBaseDiff+dynamicTab[j].d_val); break;
\r
378 case DT_JMPREL: plt = (void*)(iBaseDiff+dynamicTab[j].d_val); break;
\r
379 case DT_PLTREL: pltType = dynamicTab[j].d_val; break;
\r
380 case DT_PLTRELSZ: pltSz = dynamicTab[j].d_val; break;
\r
382 // --- Relocation ---
\r
383 case DT_REL: rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
\r
384 case DT_RELSZ: relSz = dynamicTab[j].d_val; break;
\r
385 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
\r
387 case DT_RELA: rela = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
\r
388 case DT_RELASZ: relaSz = dynamicTab[j].d_val; break;
\r
389 case DT_RELAENT: relaEntSz = dynamicTab[j].d_val; break;
\r
393 // Parse Relocation Entries
\r
396 j = relSz / relEntSz;
\r
397 for( i = 0; i < j; i++ )
\r
399 ptr = (void*)(iBaseDiff + rel[i].r_offset);
\r
400 if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, *ptr, dynsymtab, (Uint)Base) ) {
\r
405 // Parse Relocation Entries
\r
408 j = relaSz / relaEntSz;
\r
409 for( i = 0; i < j; i++ )
\r
411 ptr = (void*)(iBaseDiff + rela[i].r_offset);
\r
412 if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, rela[i].r_addend, dynsymtab, (Uint)Base) ) {
\r
418 // === Process PLT (Procedure Linkage Table) ===
\r
421 if(pltType == DT_REL)
\r
423 Elf32_Rel *pltRel = plt;
\r
424 j = pltSz / sizeof(Elf32_Rel);
\r
425 LOG("PLT Rel - plt = %p, pltSz = %i (%i ents)", plt, pltSz, j);
\r
426 for(i = 0; i < j; i++)
\r
428 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
\r
429 if( !Elf_Int_DoRelocate(pltRel[i].r_info, ptr, *ptr, dynsymtab, (Uint)Base) ) {
\r
436 Elf32_Rela *pltRela = plt;
\r
437 j = pltSz / sizeof(Elf32_Rela);
\r
438 LOG("PLT RelA - plt = %p, pltSz = %i (%i ents)", plt, pltSz, j);
\r
441 ptr = (void*)(iBaseDiff + pltRela[i].r_offset);
\r
442 if( !Elf_Int_DoRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend, dynsymtab, (Uint)Base) ) {
\r
454 LEAVE('x', hdr->entrypoint);
\r
455 return hdr->entrypoint;
\r
459 * \fn void Elf_Int_DoRelocate(Uint r_info, Uint32 *ptr, Uint32 addend, Elf32_Sym *symtab, Uint base)
\r
460 * \brief Performs a relocation
\r
461 * \param r_info Field from relocation entry
\r
462 * \param ptr Pointer to location of relocation
\r
463 * \param addend Value to add to symbol
\r
464 * \param symtab Symbol Table
\r
465 * \param base Base of loaded binary
\r
467 int Elf_Int_DoRelocate(Uint r_info, Uint32 *ptr, Uint32 addend, Elf32_Sym *symtab, Uint base)
\r
470 int type = ELF32_R_TYPE(r_info);
\r
471 int sym = ELF32_R_SYM(r_info);
\r
472 char *sSymName = symtab[sym].name;
\r
474 //LogF("Elf_Int_DoRelocate: (r_info=0x%x, ptr=0x%x, addend=0x%x, .., base=0x%x)\n",
\r
475 // r_info, ptr, addend, base);
\r
479 // Standard 32 Bit Relocation (S+A)
\r
481 if( !Elf_GetSymbol((void*)base, sSymName, &val) ) // Search this binary first
\r
482 if( !Binary_GetSymbol( sSymName, &val ) )
\r
484 LOG("%08x R_386_32 *0x%x += 0x%x('%s')", r_info, ptr, val, sSymName);
\r
485 *ptr = val + addend;
\r
488 // 32 Bit Relocation wrt. Offset (S+A-P)
\r
490 if( !Elf_GetSymbol( (void*)base, sSymName, &val ) )
\r
491 if( !Binary_GetSymbol( sSymName, &val ) )
\r
493 LOG("%08x R_386_PC32 *0x%x = 0x%x + 0x%x('%s') - 0x%x", r_info, ptr, *ptr, val, sSymName, (Uint)ptr );
\r
494 // TODO: Check if it needs the true value of ptr or the compiled value
\r
495 // NOTE: Testing using true value
\r
496 *ptr = val + addend - (Uint)ptr;
\r
499 // Absolute Value of a symbol (S)
\r
500 case R_386_GLOB_DAT:
\r
501 if( !Elf_GetSymbol( (void*)base, sSymName, &val ) )
\r
502 if( !Binary_GetSymbol( sSymName, &val ) )
\r
504 LOG("%08x R_386_GLOB_DAT *0x%x = 0x%x (%s)", r_info, ptr, val, sSymName);
\r
508 // Absolute Value of a symbol (S)
\r
509 case R_386_JMP_SLOT:
\r
510 if( !Elf_GetSymbol( (void*)base, sSymName, &val ) )
\r
511 if( !Binary_GetSymbol( sSymName, &val ) )
\r
513 LOG("%08x R_386_JMP_SLOT *0x%x = 0x%x (%s)", r_info, ptr, val, sSymName);
\r
517 // Base Address (B+A)
\r
518 case R_386_RELATIVE:
\r
519 LOG("%08x R_386_RELATIVE *0x%x = 0x%x + 0x%x", r_info, ptr, base, addend);
\r
520 *ptr = base + addend;
\r
524 LOG("Rel 0x%x: 0x%x,%i", ptr, sym, type);
\r
531 * \fn int Elf_GetSymbol(void *Base, const char *name, Uint *ret)
\r
532 * \brief Get a symbol from the loaded binary
\r
534 int Elf_GetSymbol(void *Base, const char *Name, Uint *ret)
\r
536 Elf32_Ehdr *hdr = (void*)Base;
\r
545 if(!Base) return 0;
\r
547 pBuckets = (void *) hdr->misc.HashTable;
\r
548 symtab = (void *) hdr->misc.SymTable;
\r
550 nbuckets = pBuckets[0];
\r
551 iSymCount = pBuckets[1];
\r
552 pBuckets = &pBuckets[2];
\r
553 pChains = &pBuckets[ nbuckets ];
\r
556 iNameHash = Elf_Int_HashString(Name);
\r
557 iNameHash %= nbuckets;
\r
560 i = pBuckets[ iNameHash ];
\r
561 if(symtab[i].shndx != SHN_UNDEF && strcmp(symtab[i].name, Name) == 0) {
\r
562 if(ret) *ret = symtab[ i ].value;
\r
567 while(pChains[i] != STN_UNDEF)
\r
570 if(symtab[i].shndx != SHN_UNDEF && strcmp(symtab[ i ].name, Name) == 0) {
\r
571 if(ret) *ret = symtab[ i ].value;
\r
579 * \fn Uint Elf_Int_HashString(char *str)
\r
580 * \brief Hash a string in the ELF format
\r
581 * \param str String to hash
\r
582 * \return Hash value
\r
584 Uint Elf_Int_HashString(const char *str)
\r
589 h = (h << 4) + *str++;
\r
590 if( (g = h & 0xf0000000) )
\r