apio
dc389da74e
This struct allows us to keep track of what memory is used by the loaded executable. For some reason, freeing this memory when the task exits triggers a kernel page fault, so I'm not doing that right now.
104 lines
3.4 KiB
C++
104 lines
3.4 KiB
C++
#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/stdlib.h"
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#include "std/string.h"
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#include "sys/elf/ELF.h"
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static const char* format_permissions(uint32_t flags)
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{
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static char perms[4];
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perms[0] = (flags & 4) > 0 ? 'r' : '-';
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perms[1] = (flags & 2) > 0 ? 'w' : '-';
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perms[2] = (flags & 1) > 0 ? 'x' : '-';
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perms[3] = 0;
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return perms;
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}
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ELFImage* 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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ELFImage* 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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ELFImage* image = (ELFImage*)kmalloc(sizeof(ELFImage) - sizeof(ELFSection));
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memset(image, 0, sizeof(ELFImage) - sizeof(ELFSection));
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image->entry = elf_ehdr->e_entry;
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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 address %lx, file size %ld, mem size %ld, permissions %s",
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phdr->p_vaddr, phdr->p_filesz, phdr->p_memsz, format_permissions(phdr->p_flags));
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if (!phdr->p_vaddr)
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{
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kerrorln("Address is NULL, this is invalid :(");
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return 0;
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}
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uint64_t 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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image = (ELFImage*)krealloc(image, (sizeof(ELFImage) - sizeof(ELFSection)) +
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(image->section_count + 1) * sizeof(ELFSection));
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ELFSection& section = image->sections[image->section_count];
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section.base = (uintptr_t)buffer;
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section.pages = pages;
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image->section_count++;
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}
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else { kdbgln("skipping non-loadable segment"); }
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}
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if (!image->section_count)
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{
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kfree(image);
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return 0;
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}
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return image;
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} |