exec.c

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

#include "hos.h"
unsigned long EXEC_load_body(char *buf, int len){
  // load code in free frame
  unsigned long sloc;
  printk("in EXEC load body\n");
  sloc = get_free_pgframe();
  mymemcpy(sloc, buf, len); // for now
  return sloc; 
} 
int do_execve(struct pt_regs *regs){
// regs->ecx points to the file path for exec
    char *path; int x,n; char buf[512]; unsigned long * xx, *dir0;
	unsigned long start_loc;
	path=regs->ecx;
	printk("path is %s\n",path);
    x=do_open(path);
	asm("sti\n\t"::); // we need timer int to read from disk
	n=kernel_do_read(x, buf, 512);
	asm("cli\n\t"::);
	printk("the buf read from disk is: ");
	xx=(unsigned long *)buf;
	for(x=0;x<32;x++) printk("%x ", xx[x]); 
	//wait_for_anykey();
	start_loc = EXEC_load_body(buf,n); // assume our process fits in 1 page
	// set page table
	set_page_table(current, start_loc);
	dir0 = (unsigned long *)mloc(current->mm.pgdir[0]);
	printk("aft set page table.pgdir %x, pgdir[0] %x, dir0[512] %x\n",
	       current->mm.pgdir, current->mm.pgdir[0], dir0[512]);

	printk("the code at start_loc:%x is: ",start_loc);
	xx=(unsigned long *)start_loc;
	for(x=0;x<16;x++) printk("%x ", xx[x]); 
	printk("now check paging sytem. dumping USER_PROCESS_LOCATION\n");
	xx=(unsigned long *)USER_PROCESS_LOCATION;
	for(x=0;x<16;x++) printk("%x ", xx[x]); 
	//asm("sti\n\t"::);
	//dump_directory_table(current->mm.pgdir);
	//asm("cli\n\t"::);
	// change starting ip
	printk("dumping done\n");
    regs->eip = USER_PROCESS_LOCATION; 
	   //we assume all processes starts at virt 0x200000
}

int sys_execve(struct pt_regs regs){
   printk("in sys execve\n");
   return do_execve(&regs);
}