// Simple command-line kernel monitor useful for
// controlling the kernel and exploring the system interactively.

#include <inc/stdio.h>
#include <inc/string.h>
#include <inc/memlayout.h>
#include <inc/assert.h>
#include <inc/x86.h>

#include <kern/console.h>
#include <kern/monitor.h>
#include <kern/trap.h>
#include <kern/kdebug.h>

#define CMDBUF_SIZE	80	// enough for one VGA text line


struct Command {
	const char *name;
	const char *desc;
	// return -1 to force monitor to exit
	int (*func)(int argc, char** argv, struct Trapframe* tf);
};

struct Trace {
  struct Trace *ebp;
  int eip;
  int args[];
};

static struct Command commands[] = {
	{ "help", "Display this list of commands", mon_help },
	{ "kerninfo", "Display information about the kernel", mon_kerninfo },
	{ "trace", "Display a trace through the stack", mon_backtrace },
    { "continue", "Continue execution in debug mode", mon_debug }
};
#define NCOMMANDS (sizeof(commands)/sizeof(commands[0]))

unsigned read_eip();

/***** Implementations of basic kernel monitor commands *****/

int
mon_help(int argc, char **argv, struct Trapframe *tf)
{
	int i;

	for (i = 0; i < NCOMMANDS; i++)
		cprintf("%s - %s\n", commands[i].name, commands[i].desc);
	return 0;
}

int
mon_kerninfo(int argc, char **argv, struct Trapframe *tf)
{
	extern char _start[], etext[], edata[], end[];

	cprintf("Special kernel symbols:\n");
	cprintf("  _start %08x (virt)  %08x (phys)\n", _start, _start - KERNBASE);
	cprintf("  etext  %08x (virt)  %08x (phys)\n", etext, etext - KERNBASE);
	cprintf("  edata  %08x (virt)  %08x (phys)\n", edata, edata - KERNBASE);
	cprintf("  end    %08x (virt)  %08x (phys)\n", end, end - KERNBASE);
	cprintf("Kernel executable memory footprint: %dKB\n",
		(end-_start+1023)/1024);
	return 0;
}

int
mon_backtrace(int argc, char **argv, struct Trapframe *tf)
{
  
  // my code
  uint32_t ebp_ptr = read_ebp();
  struct Trace *t = (struct Trace*) ebp_ptr;
  //cprintf("eip check = %x\n",read_eip());
  struct Eipdebuginfo info;
  
  while(t != 0){
	debuginfo_eip(t->eip,&info);
	int size = info.eip_fn_namelen;
	char name[size+1];
	int i;
	for (i=0;i<size;i++){
	  name[i] = info.eip_fn_name[i];
	}
	name[size]='\0';
	cprintf("%s:%d: %s+%08x\n",info.eip_file,info.eip_line,name,info.eip_fn_addr); 
	cprintf("ebp %08x eip %08x args %08x %08x %08x %08x %08x \n",
			t,t->eip,t->args[0],t->args[1],t->args[2], 
			t->args[3],t->args[4]);
	t = t->ebp;
  }
	return 0;
}

int mon_debug(int argc, char **argv, struct Trapframe *tf)
{
    tf->tf_eflags = tf->tf_eflags | 0x100;
    return -1;
}  


/***** Kernel monitor command interpreter *****/

#define WHITESPACE "\t\r\n "
#define MAXARGS 16

static int
runcmd(char *buf, struct Trapframe *tf)
{
	int argc;
	char *argv[MAXARGS];
	int i;

	// Parse the command buffer into whitespace-separated arguments
	argc = 0;
	argv[argc] = 0;
	while (1) {
		// gobble whitespace
		while (*buf && strchr(WHITESPACE, *buf))
			*buf++ = 0;
		if (*buf == 0)
			break;

		// save and scan past next arg
		if (argc == MAXARGS-1) {
			cprintf("Too many arguments (max %d)\n", MAXARGS);
			return 0;
		}
		argv[argc++] = buf;
		while (*buf && !strchr(WHITESPACE, *buf))
			buf++;
	}
	argv[argc] = 0;

	// Lookup and invoke the command
	if (argc == 0)
		return 0;
	for (i = 0; i < NCOMMANDS; i++) {
		if (strcmp(argv[0], commands[i].name) == 0)
			return commands[i].func(argc, argv, tf);
	}
	cprintf("Unknown command '%s'\n", argv[0]);
	return 0;
}

void
monitor(struct Trapframe *tf)
{
	char *buf;

	cprintf("Welcome to the JOS kernel monitor!\n");
	cprintf("Type 'help' for a list of commands.\n");

	if (tf != NULL)
		print_trapframe(tf);

	while (1) {
		buf = readline("K> ");
		if (buf != NULL)
			if (runcmd(buf, tf) < 0)
				break;
	}
}

// return EIP of caller.
// does not work if inlined.
// putting at the end of the file seems to prevent inlining.
unsigned
read_eip()
{
	uint32_t callerpc;
	__asm __volatile("movl 4(%%ebp), %0" : "=r" (callerpc));
	return callerpc;
}