fcallconv.c

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

#include <plan9.h>
#include <fcall.h>
#include <oldfcall.h>

extern int old9p;

static uint dumpsome(char*, char*, long);
static void fdirconv(char*, Dir*);
static char *qidtype(char*, uchar);

#define	QIDFMT	"(%.16llux %lud %s)"

int
fcallconv(va_list *arg, Fconv *f1)
{
	Fcall *f;
	int fid, type, tag, n, i;
	char buf[512], tmp[200];
	Dir *d;
	Qid *q;

	f = va_arg(*arg, Fcall*);
	type = f->type;
	fid = f->fid;
	tag = f->tag;
	switch(type){
	case Tversion:	/* 100 */
		sprint(buf, "Tversion tag %ud msize %ud version '%s'", tag, f->msize, f->version);
		break;
	case Rversion:
		sprint(buf, "Rversion tag %ud msize %ud version '%s'", tag, f->msize, f->version);
		break;
	case Tauth:	/* 102 */
		sprint(buf, "Tauth tag %ud afid %d uname %s aname %s", tag,
			f->afid, f->uname, f->aname);
		break;
	case Rauth:
		sprint(buf, "Rauth tag %ud qid " QIDFMT, tag,
			f->aqid.path, f->aqid.vers, qidtype(tmp, f->aqid.type));
		break;
	case Tattach:	/* 104 */
		sprint(buf, "Tattach tag %ud fid %d afid %d uname %s aname %s", tag,
			fid, f->afid, f->uname, f->aname);
		break;
	case Rattach:
		sprint(buf, "Rattach tag %ud qid " QIDFMT, tag,
			f->qid.path, f->qid.vers, qidtype(tmp, f->qid.type));
		break;
	case Rerror:	/* 107; 106 (Terror) illegal */
		sprint(buf, "Rerror tag %ud ename %s", tag, f->ename);
		break;
	case Tflush:	/* 108 */
		sprint(buf, "Tflush tag %ud oldtag %ud", tag, f->oldtag);
		break;
	case Rflush:
		sprint(buf, "Rflush tag %ud", tag);
		break;
	case Twalk:	/* 110 */
		n = sprint(buf, "Twalk tag %ud fid %d newfid %d nwname %d ", tag, fid, f->newfid, f->nwname);
			for(i=0; i<f->nwname; i++)
				n += sprint(buf+n, "%d:%s ", i, f->wname[i]);
		break;
	case Rwalk:
		n = sprint(buf, "Rwalk tag %ud nwqid %ud ", tag, f->nwqid);
		for(i=0; i<f->nwqid; i++){
			q = &f->wqid[i];
			n += sprint(buf+n, "%d:" QIDFMT " ", i,
				q->path, q->vers, qidtype(tmp, q->type));
		}
		break;
	case Topen:	/* 112 */
		sprint(buf, "Topen tag %ud fid %ud mode %d", tag, fid, f->mode);
		break;
	case Ropen:
		sprint(buf, "Ropen tag %ud qid " QIDFMT " iounit %ud ", tag,
			f->qid.path, f->qid.vers, qidtype(tmp, f->qid.type), f->iounit);
		break;
	case Tcreate:	/* 114 */
		sprint(buf, "Tcreate tag %ud fid %ud perm %M mode %d", tag, fid, (ulong)f->perm, f->mode);
		break;
	case Rcreate:
		sprint(buf, "Rcreate tag %ud qid " QIDFMT " iounit %ud ", tag,
			f->qid.path, f->qid.vers, qidtype(tmp, f->qid.type), f->iounit);
		break;
	case Tread:	/* 116 */
		sprint(buf, "Tread tag %ud fid %d offset %lld count %ud",
			tag, fid, f->offset, f->count);
		break;
	case Rread:
		n = sprint(buf, "Rread tag %ud count %ud ", tag, f->count);
			dumpsome(buf+n, f->data, f->count);
		break;
	case Twrite:	/* 118 */
		n = sprint(buf, "Twrite tag %ud fid %d offset %lld count %ud ",
			tag, fid, f->offset, f->count);
		dumpsome(buf+n, f->data, f->count);
		break;
	case Rwrite:
		sprint(buf, "Rwrite tag %ud count %ud", tag, f->count);
		break;
	case Tclunk:	/* 120 */
		sprint(buf, "Tclunk tag %ud fid %ud", tag, fid);
		break;
	case Rclunk:
		sprint(buf, "Rclunk tag %ud", tag);
		break;
	case Tremove:	/* 122 */
		sprint(buf, "Tremove tag %ud fid %ud", tag, fid);
		break;
	case Rremove:
		sprint(buf, "Rremove tag %ud", tag);
		break;
	case Tstat:	/* 124 */
		sprint(buf, "Tstat tag %ud fid %ud", tag, fid);
		break;
	case Rstat:
		n = sprint(buf, "Rstat tag %ud ", tag);
		if(f->nstat > sizeof tmp)
			sprint(buf+n, " stat(%d bytes)", f->nstat);
		else{
			d = (Dir*)tmp;
			(old9p?convM2Dold:convM2D)(f->stat, f->nstat, d, (char*)(d+1));
			sprint(buf+n, " stat ");
			fdirconv(buf+n+6, d);
		}
		break;
	case Twstat:	/* 126 */
		n = sprint(buf, "Twstat tag %ud fid %ud", tag, fid);
		if(f->nstat > sizeof tmp)
			sprint(buf+n, " stat(%d bytes)", f->nstat);
		else{
			d = (Dir*)tmp;
			(old9p?convM2Dold:convM2D)(f->stat, f->nstat, d, (char*)(d+1));
			sprint(buf+n, " stat ");
			fdirconv(buf+n+6, d);
		}
		break;
	case Rwstat:
		sprint(buf, "Rwstat tag %ud", tag);
		break;
	default:
		sprint(buf,  "unknown type %d", type);
	}
	strconv(buf, f1);
	return(sizeof(Fcall*));
}

static char*
qidtype(char *s, uchar t)
{
	char *p;

	p = s;
	if(t & QTDIR)
		*p++ = 'd';
	if(t & QTAPPEND)
		*p++ = 'a';
	if(t & QTEXCL)
		*p++ = 'l';
	if(t & QTMOUNT)
		*p++ = 'm';
	if(t & QTAUTH)
		*p++ = 'A';
	*p = '\0';
	return s;
}

int
dirconv(va_list *arg, Fconv *f)
{
	char buf[160];

	fdirconv(buf, va_arg(*arg, Dir*));
	strconv(buf, f);
	return(sizeof(Dir*));
}

static void
fdirconv(char *buf, Dir *d)
{
	char tmp[16];

	sprint(buf, "'%s' '%s' '%s' '%s' "
		"q " QIDFMT " m %#luo "
		"at %ld mt %ld l %lld "
		"t %d d %d",
			d->name, d->uid, d->gid, d->muid,
			d->qid.path, d->qid.vers, qidtype(tmp, d->qid.type), d->mode,
			d->atime, d->mtime, d->length,
			d->type, d->dev);
}

/*
 * dump out count (or DUMPL, if count is bigger) bytes from
 * buf to ans, as a string if they are all printable,
 * else as a series of hex bytes
 */
#define DUMPL 64

static uint
dumpsome(char *ans, char *buf, long count)
{
	int i, printable;
	char *p;

	printable = 1;
	if(count > DUMPL)
		count = DUMPL;
	for(i=0; i<count && printable; i++)
		if((buf[i]<32 && buf[i] !='\n' && buf[i] !='\t') || (uchar)buf[i]>127)
			printable = 0;
	p = ans;
	*p++ = '\'';
	if(printable){
		memmove(p, buf, count);
		p += count;
	}else{
		for(i=0; i<count; i++){
			if(i>0 && i%4==0)
				*p++ = ' ';
			sprint(p, "%2.2ux", (uchar)buf[i]);
			p += 2;
		}
	}
	*p++ = '\'';
	*p = 0;
	return p - ans;
}