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author | Tony Puccinelli | 2010-06-23 23:30:15 +0000 |
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committer | Tony Puccinelli | 2010-06-23 23:30:15 +0000 |
commit | 2edc5063a0e6a096ef01e9f7d55c0bcbb39764a0 (patch) | |
tree | eb187dfcce494e5df283deb261411123c811196d /backends/platform/gp2xwiz/gp2xwiz-loader.cpp | |
parent | 0edd30de1cf415a33cf02e798bc1714ee91c61e1 (diff) | |
download | scummvm-rg350-2edc5063a0e6a096ef01e9f7d55c0bcbb39764a0.tar.gz scummvm-rg350-2edc5063a0e6a096ef01e9f7d55c0bcbb39764a0.tar.bz2 scummvm-rg350-2edc5063a0e6a096ef01e9f7d55c0bcbb39764a0.zip |
defined various values in elf32.h and filled out load in wiz loader (including various helper procedures
svn-id: r50196
Diffstat (limited to 'backends/platform/gp2xwiz/gp2xwiz-loader.cpp')
-rw-r--r-- | backends/platform/gp2xwiz/gp2xwiz-loader.cpp | 263 |
1 files changed, 255 insertions, 8 deletions
diff --git a/backends/platform/gp2xwiz/gp2xwiz-loader.cpp b/backends/platform/gp2xwiz/gp2xwiz-loader.cpp index 2da2ee44bc..f678db9258 100644 --- a/backends/platform/gp2xwiz/gp2xwiz-loader.cpp +++ b/backends/platform/gp2xwiz/gp2xwiz-loader.cpp @@ -23,7 +23,7 @@ * */ -#if defined(DYNAMIC_MODULES) && defined(GP2X) +#if defined(DYNAMIC_MODULES) && defined(GP2XWIZ) #include <string.h> #include <stdarg.h> @@ -89,7 +89,7 @@ bool DLObject::relocate(int fd, unsigned long offset, unsigned long size) { // TODO: Loop over relocation entries for (int i = 0; i < cnt; i++) { - //Elf32_Sym *sym = ???; + //Elf32_Sym *sym = ???; //void *target = ???; @@ -109,17 +109,264 @@ bool DLObject::relocate(int fd, unsigned long offset, unsigned long size) { return true; } +bool DLObject::readElfHeader(int fd, Elf32_Ehdr *ehdr) { + + /* + if (read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr) || + memcmp(ehdr.e_ident, ELFMAG, SELFMAG) || + ehdr.e_type != 2 || ehdr.e_machine != 42 || + ehdr.e_phentsize < sizeof(phdr) || ehdr.e_shentsize != sizeof(*shdr) || + ehdr.e_phnum != 1) { + seterror("Invalid file type."); + return false; + } + */ + + // Start reading the elf header. Check for errors + if (read(fd, ehdr, sizeof(*ehdr)) != sizeof(*ehdr) || + memcmp(ehdr->e_ident, ELFMAG, SELFMAG) || // Check MAGIC + ehdr->e_type != ET_EXEC || // Check for executable + ehdr->e_machine != EM_MIPS || // Check for ARM machine type TODO: change EM_MIPS to ??_ARM and add to ELF32.H (figure out what ??_ARM should be) + ehdr->e_phentsize < sizeof(Elf32_Phdr) || // Check for size of program header + ehdr->e_shentsize != sizeof(Elf32_Shdr)) { // Check for size of section header + seterror("Invalid file type."); + return false; + } + + DBG("phoff = %d, phentsz = %d, phnum = %d\n", + ehdr->e_phoff, ehdr->e_phentsize, ehdr->e_phnum); + + return true; +} + +bool DLObject::readProgramHeaders(int fd, Elf32_Ehdr *ehdr, Elf32_Phdr *phdr, int num) { + + // Read program header + if (lseek(fd, ehdr->e_phoff + sizeof(*phdr)*num, SEEK_SET) < 0 || + read(fd, phdr, sizeof(*phdr)) != sizeof(*phdr)) { + seterror("Program header load failed."); + return false; + } + + // Check program header values + if (phdr->p_type != PT_LOAD || phdr->p_filesz > phdr->p_memsz) { + seterror("Invalid program header."); + return false; + } + + DBG("offs = %x, filesz = %x, memsz = %x, align = %x\n", + phdr->p_offset, phdr->p_filesz, phdr->p_memsz, phdr->p_align); + + return true; + +} + +bool DLObject::loadSegment(int fd, Elf32_Phdr *phdr) { + + char *baseAddress = 0; + + // Attempt to allocate memory for segment + int extra = phdr->p_vaddr % phdr->p_align; // Get extra length TODO: check logic here + DBG("extra mem is %x\n", extra); + + if (!(_segment = (char *)memalign(phdr->p_align, phdr->p_memsz + extra))) { + seterror("Out of memory.\n"); + return false; + } + DBG("allocated segment @ %p\n", _segment); + + // Get offset to load segment into + baseAddress = (char *)_segment + phdr->p_vaddr; + _segmentSize = phdr->p_memsz + extra; + + // Set bss segment to 0 if necessary (assumes bss is at the end) + if (phdr->p_memsz > phdr->p_filesz) { + DBG("Setting %p to %p to 0 for bss\n", baseAddress + phdr->p_filesz, baseAddress + phdr->p_memsz); + memset(baseAddress + phdr->p_filesz, 0, phdr->p_memsz - phdr->p_filesz); + } + // Read the segment into memory + if (lseek(fd, phdr->p_offset, SEEK_SET) < 0 || + read(fd, baseAddress, phdr->p_filesz) != (ssize_t)phdr->p_filesz) { + seterror("Segment load failed."); + return false; + } + + return true; +} + +Elf32_Shdr * DLObject::loadSectionHeaders(int fd, Elf32_Ehdr *ehdr) { + + Elf32_Shdr *shdr = NULL; + + // Allocate memory for section headers + if (!(shdr = (Elf32_Shdr *)malloc(ehdr->e_shnum * sizeof(*shdr)))) { + seterror("Out of memory."); + return NULL; + } + + // Read from file into section headers + if (lseek(fd, ehdr->e_shoff, SEEK_SET) < 0 || + read(fd, shdr, ehdr->e_shnum * sizeof(*shdr)) != + (ssize_t)(ehdr->e_shnum * sizeof(*shdr))) { + seterror("Section headers load failed."); + return NULL; + } + + return shdr; +} + +int DLObject::loadSymbolTable(int fd, Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) { + + // Loop over sections, looking for symbol table linked to a string table + for (int i = 0; i < ehdr->e_shnum; i++) { + if (shdr[i].sh_type == SHT_SYMTAB && + shdr[i].sh_entsize == sizeof(Elf32_Sym) && + shdr[i].sh_link < ehdr->e_shnum && + shdr[shdr[i].sh_link].sh_type == SHT_STRTAB && + _symtab_sect < 0) { + _symtab_sect = i; + } + } + + // Check for no symbol table + if (_symtab_sect < 0) { + seterror("No symbol table."); + return -1; + } + + DBG("Symbol section at section %d, size %x\n", _symtab_sect, shdr[_symtab_sect].sh_size); + + // Allocate memory for symbol table + if (!(_symtab = malloc(shdr[_symtab_sect].sh_size))) { + seterror("Out of memory."); + return -1; + } + + // Read symbol table into memory + if (lseek(fd, shdr[_symtab_sect].sh_offset, SEEK_SET) < 0 || + read(fd, _symtab, shdr[_symtab_sect].sh_size) != + (ssize_t)shdr[_symtab_sect].sh_size) { + seterror("Symbol table load failed."); + return -1; + } + + // Set number of symbols + _symbol_cnt = shdr[_symtab_sect].sh_size / sizeof(Elf32_Sym); + DBG("Loaded %d symbols.\n", _symbol_cnt); + + return _symtab_sect; + +} + +bool DLObject::loadStringTable(int fd, Elf32_Shdr *shdr) { + + int string_sect = shdr[_symtab_sect].sh_link; + + // Allocate memory for string table + if (!(_strtab = (char *)malloc(shdr[string_sect].sh_size))) { + seterror("Out of memory."); + return false; + } + + // Read string table into memory + if (lseek(fd, shdr[string_sect].sh_offset, SEEK_SET) < 0 || + read(fd, _strtab, shdr[string_sect].sh_size) != + (ssize_t)shdr[string_sect].sh_size) { + seterror("Symbol table strings load failed."); + return false; + } + + return true; +} + +void DLObject::relocateSymbols(Elf32_Addr offset) { + + relocCount = 0; + DBG("Relocating symbols by %x\n", offset); + + // Loop over symbols, add relocation offset + Elf32_Sym *s = (Elf32_Sym *)_symtab; + for (int c = _symbol_cnt; c--; s++) { + // Make sure we don't relocate special valued symbols + if (s->st_shndx < SHN_LOPROC) { + relocCount++; + s->st_value += offset; + if (s->st_value < (Elf32_Addr)_segment || s->st_value > (Elf32_Addr)_segment + _segmentSize) + seterror("Symbol out of bounds! st_value = %x\n", s->st_value); + + } + + } + + DBG("Relocated %d symbols.\n",relocCount); +} + +bool DLObject::relocateRels(int fd, Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) { + + // Loop over sections, finding relocation sections + for (int i = 0; i < ehdr->e_shnum; i++) { + + Elf32_Shdr *curShdr = &(shdr[i]); + //Elf32_Shdr *linkShdr = &(shdr[curShdr->sh_info]); + + if (curShdr->sh_type == SHT_REL && // Check for a relocation section + curShdr->sh_entsize == sizeof(Elf32_Rel) && // Check for proper relocation size + (int)curShdr->sh_link == _symtab_sect && // Check that the sh_link connects to our symbol table + curShdr->sh_info < ehdr->e_shnum && // Check that the relocated section exists + (shdr[curShdr->sh_info].sh_flags & SHF_ALLOC)) { // Check if relocated section resides in memory + + if (!relocate(fd, curShdr->sh_offset, curShdr->sh_size, _segment)) { + return false; + } + + } + } + + return true; +} bool DLObject::load(int fd) { - Elf32_Ehdr ehdr; // ELF header - Elf32_Phdr phdr; // Program header - Elf32_Shdr *shdr; // Section header + Elf32_Ehdr ehdr; + Elf32_Phdr phdr; + Elf32_Shdr *shdr; + bool ret = true; + + int symtab_sect = -1; + + if (readElfHeader(fd, &ehdr) == false) { + return false; + } + + for (int i = 0; i < ehdr.e_phnum; i++) { // Load our 2 segments + + fprintf(stderr, "Loading segment %d\n", i); + + if (readProgramHeaders(fd, &ehdr, &phdr, i) == false) + return false; + + if (!loadSegment(fd, &phdr)) + return false; + } + + if ((shdr = loadSectionHeaders(fd, &ehdr)) == NULL) + ret = false; + + if (ret && ((_symtab_sect = loadSymbolTable(fd, &ehdr, shdr)) < 0)) + ret = false; + + if (ret && (loadStringTable(fd, shdr) == false)) + ret = false; - //TODO: fill this out! + if (ret) + relocateSymbols((Elf32_Addr)_segment); // Offset by our segment allocated address + + if (ret && (relocateRels(fd, &ehdr, shdr) == false)) + ret = false; free(shdr); - return true; + return ret; + } bool DLObject::open(const char *path) { @@ -240,4 +487,4 @@ void dlforgetsyms(void *handle) { ((DLObject *)handle)->discard_symtab(); } -#endif /* DYNAMIC_MODULES && GP2X__WIZ */ +#endif /* DYNAMIC_MODULES && GP2XWIZ */ |