79 lines
2.4 KiB
C++
79 lines
2.4 KiB
C++
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#define MODULE "elf"
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#include "sys/elf/ELFLoader.h"
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#include "init/InitRD.h"
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#include "log/Log.h"
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#include "memory/MemoryManager.h"
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#include "misc/utils.h"
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#include "std/string.h"
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#include "sys/elf/ELF.h"
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void* ELFLoader::load_elf_from_initrd(const char* filename)
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{
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InitRD::File elf_file = InitRD::open(filename);
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if (!elf_file.addr)
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{
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kwarnln("failed to open file %s for loading", filename);
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return 0;
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}
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return load_elf_from_address((uintptr_t)elf_file.addr);
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}
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void* ELFLoader::load_elf_from_address(uintptr_t addr)
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{
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Elf64_Ehdr* elf_ehdr = (Elf64_Ehdr*)addr;
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if (strncmp((const char*)elf_ehdr->e_ident, ELFMAG, SELFMAG) != 0)
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{
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kwarnln("ELF file has invalid magic, skipping");
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return 0;
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}
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if (elf_ehdr->e_ident[EI_CLASS] != ELFCLASS64)
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{
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kwarnln("ELF file is not ELF64, skipping");
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return 0;
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}
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if (elf_ehdr->e_ident[EI_DATA] != ELFDATA2LSB)
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{
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kwarnln("ELF file is not little-endian, skipping");
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return 0;
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}
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if (elf_ehdr->e_type != ET_EXEC)
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{
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kwarnln("not supported: ELF file is not an executable");
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return 0;
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}
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if (elf_ehdr->e_machine != EM_MACH)
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{
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kwarnln("unsupported target machine");
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return 0;
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}
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if (elf_ehdr->e_phnum == 0)
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{
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kwarnln("ELF file has no PHDRS");
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return 0;
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}
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int i;
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Elf64_Phdr* phdr;
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for (phdr = (Elf64_Phdr*)((uint64_t)addr + elf_ehdr->e_phoff), i = 0; i < elf_ehdr->e_phnum;
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i++, phdr = (Elf64_Phdr*)((uint8_t*)phdr + elf_ehdr->e_phentsize))
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{
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if (phdr->p_type == PT_LOAD)
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{
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kdbgln("loading loadable segment at vaddr %lx, filesz %ld, memsz %ld", phdr->p_vaddr, phdr->p_filesz,
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phdr->p_memsz);
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if (!phdr->p_vaddr)
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{
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kerrorln("vaddr is NULL, this is invalid :(");
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return 0;
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}
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int pages = Utilities::get_blocks_from_size(0x1000, phdr->p_memsz);
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void* buffer = MemoryManager::get_pages_at(phdr->p_vaddr, pages,
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phdr->p_flags & 2 ? MAP_READ_WRITE | MAP_USER : MAP_USER);
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memcpy(buffer, (void*)(addr + phdr->p_offset), phdr->p_filesz);
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memset((void*)((uint64_t)buffer + phdr->p_filesz), 0, phdr->p_memsz - phdr->p_filesz);
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}
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else { kdbgln("skipping non-loadable segment"); }
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}
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return (void*)elf_ehdr->e_entry;
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}
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