9fsys.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

			goto error;
		}
		vtMemFree(de.elem);
		de.elem = vtStrDup(argv[1]);
	}
	if(strcmp(argv[2], "-") != 0){
		if(!validUserName(argv[2])){
			vtSetError("console wstat - bad uid");
			goto error;
		}
		vtMemFree(de.uid);
		de.uid = vtStrDup(argv[2]);
	}
	if(strcmp(argv[3], "-") != 0){
		if(!validUserName(argv[3])){
			vtSetError("console wstat - bad gid");
			goto error;
		}
		vtMemFree(de.gid);
		de.gid = vtStrDup(argv[3]);
	}
	if(strcmp(argv[4], "-") != 0){
		if(!fsysParseMode(argv[4], &de.mode)){
			vtSetError("console wstat - bad mode");
			goto error;
		}
	}
	if(strcmp(argv[5], "-") != 0){
		de.size = strtoull(argv[5], &p, 0);
		if(argv[5][0] == '\0' || *p != '\0' || (vlong)de.size < 0){
			vtSetError("console wstat - bad length");
			goto error;
		}
	}

	if(!fileSetDir(f, &de, uidadm)){
		vtSetError("console wstat - %R");
		goto error;
	}
	deCleanup(&de);

	if(!fileGetDir(f, &de)){
		vtSetError("console wstat - stat2 - %R");
		goto error;
	}
	fsysPrintStat("\tnew: w", argv[0], &de);
	deCleanup(&de);
	fileDecRef(f);
	vtRUnlock(fsys->fs->elk);

	return 1;

error:
	deCleanup(&de);	/* okay to do this twice */
	fileDecRef(f);
	vtRUnlock(fsys->fs->elk);
	return 0;
}

static void
fsckClri(Fsck *fsck, char *name, MetaBlock *mb, int i, Block *b)
{
	USED(name);

	if((fsck->flags&DoClri) == 0)
		return;

	mbDelete(mb, i);
	mbPack(mb);
	blockDirty(b);	
}

static void
fsckClose(Fsck *fsck, Block *b, u32int epoch)
{
	Label l;

	if((fsck->flags&DoClose) == 0)
		return;
	l = b->l;
	if(l.state == BsFree || (l.state&BsClosed)){
		consPrint("%#ux is already closed\n", b->addr);
		return;
	}
	if(epoch){	
		l.state |= BsClosed;
		l.epochClose = epoch;
	}else
		l.state = BsFree;
		
	if(!blockSetLabel(b, &l, 0))
		consPrint("%#ux setlabel: %R\n", b->addr);
}

static void
fsckClre(Fsck *fsck, Block *b, int offset)
{
	Entry e;

	if((fsck->flags&DoClre) == 0)
		return;
	if(offset<0 || offset*VtEntrySize >= fsck->bsize){
		consPrint("bad clre\n");
		return;
	}
	memset(&e, 0, sizeof e);
	entryPack(&e, b->data, offset);
	blockDirty(b);
}

static void
fsckClrp(Fsck *fsck, Block *b, int offset)
{
	if((fsck->flags&DoClrp) == 0)
		return;
	if(offset<0 || offset*VtScoreSize >= fsck->bsize){
		consPrint("bad clre\n");
		return;
	}
	memmove(b->data+offset*VtScoreSize, vtZeroScore, VtScoreSize);
	blockDirty(b);
}

static int
fsysCheck(Fsys *fsys, int argc, char *argv[])
{
	int i, halting;
	char *usage = "usage: [fsys name] check [-v] [options]";
	Fsck fsck;
	Block *b;
	Super super;

	memset(&fsck, 0, sizeof fsck);
	fsck.fs = fsys->fs;
	fsck.clri = fsckClri;
	fsck.clre = fsckClre;
	fsck.clrp = fsckClrp;
	fsck.close = fsckClose;
	fsck.print = consPrint;

	ARGBEGIN{
	default:
		return cliError(usage);
	}ARGEND

	for(i=0; i<argc; i++){
		if(strcmp(argv[i], "pblock") == 0)
			fsck.printblocks = 1;
		else if(strcmp(argv[i], "pdir") == 0)
			fsck.printdirs = 1;
		else if(strcmp(argv[i], "pfile") == 0)
			fsck.printfiles = 1;
		else if(strcmp(argv[i], "bclose") == 0)
			fsck.flags |= DoClose;
		else if(strcmp(argv[i], "clri") == 0)
			fsck.flags |= DoClri;
		else if(strcmp(argv[i], "clre") == 0)
			fsck.flags |= DoClre;
		else if(strcmp(argv[i], "clrp") == 0)
			fsck.flags |= DoClrp;
		else if(strcmp(argv[i], "fix") == 0)
			fsck.flags |= DoClose|DoClri|DoClre|DoClrp;
		else if(strcmp(argv[i], "venti") == 0)
			fsck.useventi = 1;
		else if(strcmp(argv[i], "snapshot") == 0)
			fsck.walksnapshots = 1;
		else{
			consPrint("unknown option '%s'\n", argv[i]);
			return cliError(usage);
		}
	}

	halting = fsys->fs->halted==0;
	if(halting)
		fsHalt(fsys->fs);
	if(fsys->fs->arch){
		b = superGet(fsys->fs->cache, &super);
		if(b == nil){
			consPrint("could not load super block\n");
			goto Out;
		}
		blockPut(b);
		if(super.current != NilBlock){
			consPrint("cannot check fs while archiver is running; wait for it to finish\n");
			goto Out;
		}
	}
	fsCheck(&fsck);
	consPrint("fsck: %d clri, %d clre, %d clrp, %d bclose\n",
		fsck.nclri, fsck.nclre, fsck.nclrp, fsck.nclose);
Out:
	if(halting)
		fsUnhalt(fsys->fs);
	return 1;
}

static int
fsysVenti(char* name, int argc, char* argv[])
{
	int r;
	char *host;
	char *usage = "usage: [fsys name] venti [address]";
	Fsys *fsys;

	ARGBEGIN{
	default:
		return cliError(usage);
	}ARGEND

	if(argc == 0)
		host = nil;
	else if(argc == 1)
		host = argv[0];
	else
		return cliError(usage);

	if((fsys = _fsysGet(name)) == nil)
		return 0;

	vtLock(fsys->lock);
	if(host == nil)
		host = fsys->venti;
	else{
		vtMemFree(fsys->venti);
		if(host[0])
			fsys->venti = vtStrDup(host);
		else{
			host = nil;
			fsys->venti = nil;
		}
	}

	/* already open: do a redial */
	if(fsys->fs != nil){
		if(fsys->session == nil){
			vtSetError("file system was opened with -V");
			r = 0;
			goto out;
		}
		r = 1;
		if(!vtRedial(fsys->session, host)
		|| !vtConnect(fsys->session, 0))
			r = 0;
		goto out;
	}

	/* not yet open: try to dial */
	if(fsys->session)
		vtClose(fsys->session);
	r = 1;
	if((fsys->session = vtDial(host, 0)) == nil
	|| !vtConnect(fsys->session, 0))
		r = 0;
out:
	vtUnlock(fsys->lock);
	fsysPut(fsys);
	return r;
}

static int
fsysOpen(char* name, int argc, char* argv[])
{
	char *p, *host;
	Fsys *fsys;
	long ncache;
	int noauth, noventi, noperm, rflag, wstatallow;
	char *usage = "usage: fsys name open [-APVWr] [-c ncache]";

	ncache = 1000;
	noauth = noperm = wstatallow = noventi = 0;
	rflag = OReadWrite;

	ARGBEGIN{
	default:
		return cliError(usage);
	case 'A':
		noauth = 1;
		break;
	case 'P':
		noperm = 1;
		break;
	case 'V':
		noventi = 1;
		break;
	case 'W':
		wstatallow = 1;
		break;
	case 'c':
		p = ARGF();
		if(p == nil)
			return cliError(usage);
		ncache = strtol(argv[0], &p, 0);
		if(ncache <= 0 || p == argv[0] || *p != '\0')
			return cliError(usage);
		break;
	case 'r':
		rflag = OReadOnly;
		break;
	}ARGEND
	if(argc)
		return cliError(usage);

	if((fsys = _fsysGet(name)) == nil)
		return 0;

	vtLock(fsys->lock);
	if(fsys->fs != nil){
		vtSetError(EFsysBusy, fsys->name);
		vtUnlock(fsys->lock);
		fsysPut(fsys);
		return 0;
	}

	if(noventi){
		if(fsys->session){
			vtClose(fsys->session);
			fsys->session = nil;
		}
	}
	else if(fsys->session == nil){
		if(fsys->venti && fsys->venti[0])
			host = fsys->venti;
		else
			host = nil;
		fsys->session = vtDial(host, 1);
		if(!vtConnect(fsys->session, nil) && !noventi)
			fprint(2, "warning: connecting to venti: %R\n");
	}
	if((fsys->fs = fsOpen(fsys->dev, fsys->session, ncache, rflag)) == nil){
		vtSetError("fsOpen: %R");
		vtUnlock(fsys->lock);
		fsysPut(fsys);
		return 0;
	}
	fsys->noauth = noauth;
	fsys->noperm = noperm;
	fsys->wstatallow = wstatallow;
	vtUnlock(fsys->lock);
	fsysPut(fsys);

	if(strcmp(name, "main") == 0)
		usersFileRead(nil);

	return 1;
}

static int
fsysUnconfig(char* name, int argc, char* argv[])
{
	Fsys *fsys, **fp;
	char *usage = "usage: fsys name unconfig";

	ARGBEGIN{
	default:
		return cliError(usage);
	}ARGEND
	if(argc)
		return cliError(usage);

	vtLock(sbox.lock);
	fp = &sbox.head;
	for(fsys = *fp; fsys != nil; fsys = fsys->next){
		if(strcmp(fsys->name, name) == 0)
			break;
		fp = &fsys->next;
	}
	if(fsys == nil){
		vtSetError(EFsysNotFound, name);
		vtUnlock(sbox.lock);
		return 0;
	}
	if(fsys->ref != 0 || fsys->fs != nil){
		vtSetError(EFsysBusy, fsys->name);
		vtUnlock(sbox.lock);
		return 0;
	}
	*fp = fsys->next;
	vtUnlock(sbox.lock);

	if(fsys->session != nil){
		vtClose(fsys->session);
		vtFree(fsys->session);
	}
	if(fsys->venti != nil)
		vtMemFree(fsys->venti);
	if(fsys->dev != nil)
		vtMemFree(fsys->dev);
	if(fsys->name != nil)
		vtMemFree(fsys->name);
	vtMemFree(fsys);

	return 1;
}

static int
fsysConfig(char* name, int argc, char* argv[])
{
	Fsys *fsys;
	char *usage = "usage: fsys name config dev";

	ARGBEGIN{
	default:
		return cliError(usage);
	}ARGEND
	if(argc != 1)
		return cliError(usage);

	if((fsys = _fsysGet(argv[0])) != nil){
		vtLock(fsys->lock);
		if(fsys->fs != nil){
			vtSetError(EFsysBusy, fsys->name);
			vtUnlock(fsys->lock);
			fsysPut(fsys);
			return 0;
		}
		vtMemFree(fsys->dev);
		fsys->dev = vtStrDup(argv[0]);
		vtUnlock(fsys->lock);
	}
	else if((fsys = fsysAlloc(name, argv[0])) == nil)
		return 0;

	fsysPut(fsys);

	return 1;
}

static struct {
	char*	cmd;
	int	(*f)(Fsys*, int, char**);
	int	(*f1)(char*, int, char**);
} fsyscmd[] = {
	{ "close",	fsysClose, },
	{ "config",	nil, fsysConfig, },
	{ "open",	nil, fsysOpen, },
	{ "unconfig",	nil, fsysUnconfig, },
	{ "venti",	nil, fsysVenti, },

	{ "bfree",	fsysBfree, },
	{ "block",	fsysBlock, },
	{ "check",	fsysCheck, },
	{ "clre",	fsysClre, },
	{ "clri",	fsysClri, },
	{ "clrp",	fsysClrp, },
	{ "create",	fsysCreate, },
	{ "df",		fsysDf, },
	{ "epoch",	fsysEpoch, },
	{ "halt",	fsysHalt, },
	{ "label",	fsysLabel, },
	{ "remove",	fsysRemove, },
	{ "snap",	fsysSnap, },
	{ "snaptime",	fsysSnapTime, },
	{ "snapclean",	fsysSnapClean, },
	{ "stat",	fsysStat, },
	{ "sync",	fsysSync, },
	{ "unhalt",	fsysUnhalt, },
	{ "wstat",	fsysWstat, },
	{ "vac",	fsysVac, },

	{ nil,		nil, },
};

static int
fsysXXX1(Fsys *fsys, int i, int argc, char* argv[])
{
	int r;

	vtLock(fsys->lock);
	if(fsys->fs == nil){
		vtUnlock(fsys->lock);
		vtSetError(EFsysNotOpen, fsys->name);
		return 0;
	}

	if(fsys->fs->halted
	&& fsyscmd[i].f != fsysUnhalt && fsyscmd[i].f != fsysCheck){
		vtSetError("file system %s is halted", fsys->name);
		vtUnlock(fsys->lock);
		return 0;
	}

	r = (*fsyscmd[i].f)(fsys, argc, argv);
	vtUnlock(fsys->lock);
	return r;
}

static int
fsysXXX(char* name, int argc, char* argv[])
{
	int i, r;
	Fsys *fsys;

	for(i = 0; fsyscmd[i].cmd != nil; i++){
		if(strcmp(fsyscmd[i].cmd, argv[0]) == 0)
			break;
	}

	if(fsyscmd[i].cmd == nil){
		vtSetError("unknown command - '%s'", argv[0]);
		return 0;
	}

	/* some commands want the name... */
	if(fsyscmd[i].f1 != nil){
		if(strcmp(name, FsysAll) == 0){
			vtSetError("cannot use fsys %#q with %#q command", FsysAll, argv[0]);
			return 0;
		}
		return (*fsyscmd[i].f1)(name, argc, argv);
	}

	/* ... but most commands want the Fsys */
	if(strcmp(name, FsysAll) == 0){
		r = 1;
		vtRLock(sbox.lock);
		for(fsys = sbox.head; fsys != nil; fsys = fsys->next){
			fsys->ref++;
			r = fsysXXX1(fsys, i, argc, argv) && r;
			fsys->ref--;
		}
		vtRUnlock(sbox.lock);
	}else{
		if((fsys = _fsysGet(name)) == nil)
			return 0;
		r = fsysXXX1(fsys, i, argc, argv);
		fsysPut(fsys);
	}
	return r;
}

static int
cmdFsysXXX(int argc, char* argv[])
{
	char *name;

	if((name = sbox.curfsys) == nil){
		vtSetError(EFsysNoCurrent, argv[0]);
		return 0;
	}

	return fsysXXX(name, argc, argv);
}

static int
cmdFsys(int argc, char* argv[])
{
	Fsys *fsys;
	char *usage = "usage: fsys [name ...]";

	ARGBEGIN{
	default:
		return cliError(usage);
	}ARGEND

	if(argc == 0){
		vtRLock(sbox.lock);
		for(fsys = sbox.head; fsys != nil; fsys = fsys->next)
			consPrint("\t%s\n", fsys->name);
		vtRUnlock(sbox.lock);
		return 1;
	}
	if(argc == 1){
		fsys = nil;
		if(strcmp(argv[0], FsysAll) != 0 && (fsys = fsysGet(argv[0])) == nil)
			return 0;
		sbox.curfsys = vtStrDup(argv[0]);
		consPrompt(sbox.curfsys);
		if(fsys)
			fsysPut(fsys);
		return 1;
	}

	return fsysXXX(argv[0], argc-1, argv+1);
}

int
fsysInit(void)
{
	int i;

	fmtinstall('H', encodefmt);
	fmtinstall('V', scoreFmt);
	fmtinstall('R', vtErrFmt);
	fmtinstall('L', labelFmt);

	sbox.lock = vtLockAlloc();

	cliAddCmd("fsys", cmdFsys);
	for(i = 0; fsyscmd[i].cmd != nil; i++){
		if(fsyscmd[i].f != nil)
			cliAddCmd(fsyscmd[i].cmd, cmdFsysXXX);
	}
	/* the venti cmd is special: the fs can be either open or closed */
	cliAddCmd("venti", cmdFsysXXX);
	cliAddCmd("printconfig", cmdPrintConfig);

	return 1;
}