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// MIT License, Copyright (c) 2020 Marvin Borner
#include <errno.h>
#include <fs.h>
#include <load.h>
#include <mem.h>
#include <mm.h>
#include <str.h>
#define PROC_STACK_SIZE 0x4000
res elf_load(const char *path, struct proc *proc)
{
if (!path || !memory_valid(path) || !proc)
return -EFAULT;
struct stat s = { 0 };
memory_bypass_enable();
res stat = vfs_stat(path, &s);
memory_bypass_disable();
if (stat != 0)
return stat;
struct elf_header header = { 0 };
memory_bypass_enable();
res read = vfs_read(path, &header, 0, sizeof(header));
memory_bypass_disable();
if (read < 0)
return read;
if (read != sizeof(header))
return -ENOEXEC;
strcpy(proc->name, path);
// Valid?
u8 *magic = header.ident;
u8 valid_magic = magic[ELF_IDENT_MAG0] == ELF_MAG0 && magic[ELF_IDENT_MAG1] == ELF_MAG1 &&
magic[ELF_IDENT_MAG2] == ELF_MAG2 && magic[ELF_IDENT_MAG3] == ELF_MAG3 &&
magic[ELF_IDENT_CLASS] == ELF_IDENT_CLASS_32 &&
magic[ELF_IDENT_DATA] == ELF_IDENT_DATA_LSB;
if (!valid_magic || (header.type != ELF_ETYPE_REL && header.type != ELF_ETYPE_EXEC) ||
header.version != 1 || header.machine != ELF_MACHINE_386)
return -ENOEXEC;
for (u32 i = 0; i < header.phnum; i++) {
struct elf_program program = { 0 };
memory_bypass_enable();
if (vfs_read(path, &program, header.phoff + header.phentsize * i,
sizeof(program)) != sizeof(program)) {
memory_bypass_disable();
return -ENOEXEC;
}
memory_bypass_disable();
if (program.vaddr == 0)
continue;
if (!memory_is_user(program.vaddr))
return -ENOEXEC;
struct page_dir *prev;
memory_backup_dir(&prev);
memory_switch_dir(proc->page_dir);
struct memory_range vrange = memory_range_around(program.vaddr, program.memsz);
struct memory_range prange = physical_alloc(vrange.size);
virtual_map(proc->page_dir, prange, vrange.base, MEMORY_CLEAR | MEMORY_USER);
memory_bypass_enable();
if ((u32)vfs_read(proc->name, (void *)program.vaddr, program.offset,
program.filesz) != program.filesz) {
memory_bypass_disable();
memory_switch_dir(prev);
return -ENOEXEC;
}
memory_bypass_disable();
memory_switch_dir(prev);
}
struct page_dir *prev;
memory_backup_dir(&prev);
memory_switch_dir(proc->page_dir);
u32 stack = (u32)memory_alloc(proc->page_dir, PROC_STACK_SIZE, MEMORY_USER | MEMORY_CLEAR);
proc->regs.ebp = stack + PROC_STACK_SIZE;
proc->regs.useresp = stack + PROC_STACK_SIZE;
proc->regs.eip = header.entry;
proc->entry = header.entry;
memory_switch_dir(prev);
return 0;
}
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