os/kernel/kernel.c
2019-05-23 17:38:26 -05:00

111 lines
2.8 KiB
C

#include <grub/text_fb_info.h>
#include <stdlib.h>
#include <tasking.h>
#include <string.h>
#include <memory.h>
#include <grub/multiboot2.h>
#include <stdint.h>
#include "../cpu/cpu_init.h"
#include "vga_err.h"
#include "elf.h"
typedef struct {
char filename[100];
char mode[8];
char uid[8];
char gid[8];
char size[12];
char mtime[12];
char chksum[8];
char typeflag[1];
} tar_header;
static long initrd_sz;
static char* initrd;
typedef int (*func_ptr)();
static struct multiboot_boot_header_tag* tags;
static void read_initrd(struct multiboot_boot_header_tag* tags) {
struct multiboot_tag* tag=(struct multiboot_tag*)(tags+1);
while (tag->type!=0) {
switch (tag->type) {
case MULTIBOOT_TAG_TYPE_MODULE: {
struct multiboot_tag_module* mod=(struct multiboot_tag_module*) tag;
initrd=malloc(sizeof(char)*(mod->mod_end-mod->mod_start));
initrd_sz=mod->mod_end-mod->mod_start;
memcpy(initrd,(void*)(mod->mod_start+0xC0000000),mod->mod_end-mod->mod_start);
}
}
tag=(struct multiboot_tag*)((char*)tag+((tag->size+7)&0xFFFFFFF8));
}
}
uint32_t getsize(const char *in) {
uint32_t size=0;
uint32_t j;
uint32_t count=1;
for (j=11;j>0;j--,count*=8) {
size+=((in[j-1]-'0')*count);
}
return size;
}
void kmain(struct multiboot_boot_header_tag* hdr) {
tags=hdr;
cpu_init(tags);
vga_init((char*)0xC00B8000);
read_initrd(tags);
int pos=0;
uint32_t datapos;
tar_header tar_hdr;
for (int i=0;;i++) {
char* tar_hdr_ptr=(char*)&tar_hdr;
for (size_t i=0;i<sizeof(tar_hdr);i++) {
tar_hdr_ptr[i]=initrd[pos+i];
}
if (tar_hdr.filename[0]=='\0') break;
uint32_t size=getsize(tar_hdr.size);
pos+=512;
if (strcmp(tar_hdr.filename,"init")==0) {
datapos=pos;
break;
}
pos+=size;
}
elf_header header;
pos=datapos;
char* hdr_ptr=(char*)&header;
for (size_t i=0;i<sizeof(elf_header);i++) {
hdr_ptr[i]=initrd[pos];
pos++;
}
if (header.magic!=ELF_MAGIC) {
vga_write_string("[INFO] Invalid magic number for prog.elf\n");
} else {
void* cr3=new_address_space();
for (int i=0;i<header.pheader_ent_nm;i++) {
elf_pheader pheader;
pos=(header.prog_hdr)+(header.pheader_ent_sz*i)+datapos;
char* phdr_ptr=(char*)&pheader;
for (size_t i=0;i<sizeof(elf_pheader);i++) {
phdr_ptr[i]=initrd[pos];
pos++;
}
char* ptr=alloc_memory(((pheader.memsz)/4096)+1);
memset(ptr,0,pheader.memsz);
if (pheader.filesz>0) {
pos=pheader.offset+datapos;
for (size_t i=0;i<pheader.filesz;i++) {
ptr[i]=initrd[pos];
pos++;
}
}
copy_data(cr3,ptr,pheader.memsz,(void*)pheader.vaddr);
}
createTaskCr3((void*)header.entry,cr3);
for(;;) {
yield();
}
}
}