snap.h

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

typedef struct Data	Data;
typedef struct Page	Page;
typedef struct Proc	Proc;
typedef struct Seg	Seg;

enum {
	Psegment = 0,
	Pfd,
	Pfpregs,
	Pkregs,
	Pnoteid,
	Pns,
	Pproc,
	Pregs,
	Pstatus,
	Npfile,

	Pagesize = 1024,	/* need not relate to kernel */
};

struct Data {
	ulong len;
	char data[1];
};

struct Seg {
	char*	name;
	uvlong	offset;
	uvlong	 len;
	Page**	pg;
	int	npg;
};

struct Page {
	Page*	link;
	ulong	len;
	char*	data;

	/* when page is written, these hold the ptr to it */
	int	written;
	int	type;
	ulong	pid;
	uvlong	offset;
};

struct Proc {
	Proc *link;
	long	pid;
	Data*	d[Npfile];
	Seg**	seg;	/* memory segments */
	int	nseg;
	Seg*	text;	/* text file */
};

extern char *pfile[Npfile];

Proc*	snap(long pid, int usetext);
void*	emalloc(ulong);
void*	erealloc(void*, ulong);
char*	estrdup(char*);
void	writesnap(Biobuf*, Proc*);
Page*	datapage(char *p, long len);
Proc*	readsnap(Biobuf *b);
Page*	findpage(Proc *plist, long pid, int type, uvlong off);

int	debug;