#include	"u.h"#include	"lib.h"#include	"mem.h"#include	"dat.h"#include	"fns.h"#include	"error.h" #include	"netif.h" typedef struct Ram	Ram;struct Ram{	QLock lk;	Ram	*next;	int	ref;	/* simple for now */	uchar **pages;	int pagecount;	int size;	int	qref[2];	ulong	path;}; struct{	Lock lk;	ulong	path;} ramalloc; enum{	Qdir,	Qdata0,	Qctl,}; Dirtab ramdir[] ={	".",		{Qdir,0,QTDIR},	0,		DMDIR|0500,	"data",		{Qdata0},	0,		0600,	"ctl",	{Qctl},	0,		0600,};#define NPIPEDIR 3 static voidraminit(void){} /* *  create a ram, no streams are created until an open */static Chan*ramattach(char *spec){	Ram *p;	Chan *c; 	c = devattach('R', spec);	p = malloc(sizeof(Ram));	if(p == 0)		exhausted("memory");	p->ref = 1;	p->size = 0;	p->pagecount = 1;	p->pages = mallocz(sizeof(char *), 1);	p->pages[0] = mallocz(BY2PG, 1);	lock(&ramalloc.lk);	p->path = ++ramalloc.path;	unlock(&ramalloc.lk); 	mkqid(&c->qid, NETQID(2*p->path, Qdir), 0, QTDIR);	c->aux = p;	c->dev = 0;	return c;} static intramgen(Chan *c, char *name, Dirtab *tab, int ntab, int i, Dir *dp){	Qid q;	int len;	Ram *p; 	if(i == DEVDOTDOT){		devdir(c, c->qid, "#R", 0, eve, DMDIR|0555, dp);		return 1;	}	i++;	/* skip . */	if(tab==0 || i>=ntab)		return -1; 	tab += i;	p = c->aux;	switch((ulong)tab->qid.path){	case Qdata0:		len = p->size;		break;	case Qctl:		len = 0;		break;	default:		len = tab->length;		break;	}	mkqid(&q, NETQID(NETID(c->qid.path), tab->qid.path), 0, QTFILE);	devdir(c, q, tab->name, len, eve, tab->perm, dp);	return 1;}  static Walkqid*ramwalk(Chan *c, Chan *nc, char **name, int nname){	Walkqid *wq;	Ram *p; 	wq = devwalk(c, nc, name, nname, ramdir, NPIPEDIR, ramgen);	if(wq != nil && wq->clone != nil && wq->clone != c){		p = c->aux;		qlock(&p->lk);		p->ref++;		if(c->flag & COPEN){			print("channel open in ramwalk\n");			switch(NETTYPE(c->qid.path)){			case Qdata0:				p->qref[0]++;				break;			case Qctl:				p->qref[1]++;				break;			}		}		qunlock(&p->lk);	}	return wq;} static intramstat(Chan *c, uchar *db, int n){	Ram *p;	Dir dir; 	p = c->aux; 	switch(NETTYPE(c->qid.path)){	case Qdir:		devdir(c, c->qid, ".", 0, eve, DMDIR|0555, &dir);		break;	case Qdata0:		devdir(c, c->qid, "data", p->size, eve, 0600, &dir);		break;	case Qctl:		devdir(c, c->qid, "ctl", 0, eve, 0600, &dir);		break;	default:		panic("ramstat");	}	n = convD2M(&dir, db, n);	if(n < BIT16SZ)		error(Eshortstat);	return n;} /* *  if the stream doesn't exist, create it */static Chan*ramopen(Chan *c, int omode){	Ram *p; 	if(c->qid.type & QTDIR){		if(omode != OREAD)			error(Ebadarg);		c->mode = omode;		c->flag |= COPEN;		c->offset = 0;		return c;	} 	p = c->aux;	qlock(&p->lk);	switch(NETTYPE(c->qid.path)){	case Qdata0:		p->qref[0]++;		break;	case Qctl:		p->qref[1]++;		break;	}	qunlock(&p->lk); 	c->mode = openmode(omode);	c->flag |= COPEN;	c->offset = 0;	c->iounit = qiomaxatomic;	return c;} static voidramclose(Chan *c){	Ram *p; 	p = c->aux;	qlock(&p->lk); 	if(c->flag & COPEN){		switch(NETTYPE(c->qid.path)){		case Qdata0:			p->qref[0]--;			break;		case Qctl:			p->qref[1]--;			break;		}	} 	/*	 *  free the structure on last close	 */	p->ref--;	if(p->ref == 0){		int i;		qunlock(&p->lk);		for(i = 0; i < p->pagecount; i++)			free(p->pages[i]);		free(p->pages);		free(p);	} else		qunlock(&p->lk);} static long rampageread(Ram *p, void *va, long n, vlong offset){	int i;	long total, offinpage, leninpage; 	total = n; 	/* figure out what range we can actually read */	if(offset > p->size)		return 0;	if(offset + n > p->size) 		n = p->size - offset;	/* granular copy */	for(i = offset / BY2PG; n > 0; i++) {		/* i is the page */		offinpage = offset & (BY2PG - 1);		leninpage = BY2PG - offinpage;		/* unless there is too little left ... */		if(leninpage > n)			leninpage = n;		memcpy(va, p->pages[i] + offinpage, leninpage);		offset += offinpage;		n -= leninpage; 		va += leninpage;	}	return total;} static longramread(Chan *c, void *va, long n, vlong offset){	Ram *p;	char *buf, *s, *e; 	p = c->aux; 	switch(NETTYPE(c->qid.path)){	case Qdir:		return devdirread(c, va, n, ramdir, NPIPEDIR, ramgen);	case Qdata0:		return rampageread(p, va, n, offset);	case Qctl:		buf = smalloc(8192);		s = buf;		e = buf + 8192;		s = seprint(s, e, "pages %p count %d ", p->pages, p->pagecount);		seprint(s, e, "size %d\n", p->size);		n = readstr(offset, va, n, buf);		free(buf);		return n;	default:		panic("ramread");	}	return -1;	/* not reached */} /* for the range offset .. offset + n, make sure we have pages */static void pages(Ram *p, long n, vlong offset){	int i;	int newpagecount;	uchar **newpages; 	newpagecount = (offset + n + BY2PG-1)/BY2PG;	if(newpagecount > p->pagecount) {		newpages = mallocz(sizeof(char *) * newpagecount, 1);		if(!newpages)			error("No more pages in devram");		memcpy(newpages, p->pages, sizeof(char *) * p->pagecount);		free(p->pages);		p->pages = newpages;		p->pagecount = newpagecount;		/* now allocate them */		for(i = offset / BY2PG; i < newpagecount; i++) {			if(p->pages[i])				continue;			p->pages[i] = mallocz(BY2PG, 1);		}	}} static long rampagewrite(Ram *p, void *va, long n, vlong offset){	int i;	long total, offinpage, leninpage;	long newsize; 	total = n;	pages(p, n, offset);		/* granular copy */	newsize = offset + n;	for(i = offset / BY2PG; n > 0; i++) {		/* i is the page */		offinpage = offset & (BY2PG - 1);		leninpage = BY2PG - offinpage;		/* unless there is too little left ... */		if(leninpage > n)			leninpage = n;		memcpy(p->pages[i] + offinpage, va, leninpage);		offset += leninpage;		n -= leninpage; 		va += leninpage;	}	p->size = newsize > p->size? newsize : p->size;	return total;}static longramwrite(Chan *c, void *va, long n, vlong offset){	Ram *p;	int i;	uchar **new;	uchar *page; 	if(!islo())		print("ramwrite hi %lux\n", getcallerpc(&c));	p = c->aux;	switch(NETTYPE(c->qid.path)){	case Qdata0:		n = rampagewrite(p, va, n, offset);		break; 	case Qctl:		if(strcmp(va, "free") == 0) {			new = mallocz(sizeof(char *), 1);			page = p->pages[0];			for(i = 1; i < p->pagecount; i++)				free(p->pages[i]);			free(p->pages);			p->pages = new;			p->pages[0] = page;			p->size = 0;			p->pagecount = 1;		} else {			error("bad command");		}		break; 	default:		panic("ramwrite");	} 	return n;}  Dev ramdevtab = {	'R',	"ram", 	devreset,	raminit,	devshutdown,	ramattach,	ramwalk,	ramstat,	ramopen,	devcreate,	ramclose,	ramread,	devbread,	ramwrite,	devbwrite,	devremove,	devwstat,};