config.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

					"ipmask%d %I\n", i, ipaddr[i].defmask);
		}
		putbuf(p);
		f.modconf = 0;
		f.newconf = 0;
		print("config block written\n");
		goto start;
	}
	putbuf(p);

	print("service    %s\n", service);
	print("ipauth  %I\n", authip);
	print("ipsntp  %I\n", sntpip);
	for(i=0; i<10; i++) {
		if(isvalidip(ipaddr[i].sysip)) {
			print("ip%d     %I\n", i, ipaddr[i].sysip);
			print("ipgw%d   %I\n", i, ipaddr[i].defgwip);
			print("ipmask%d %I\n", i, ipaddr[i].defmask);
		}
	}

loop:
	/*
	 * part 2 -- squeeze out the deleted filesystems
	 */
	for(fs=filsys; fs->name; fs++)
		if(fs->conf == 0) {
			for(; fs->name; fs++)
				*fs = *(fs+1);
			goto loop;
		}
	if(filsys[0].name == 0)
		panic("no filsys");

	/*
	 * part 3 -- compile the device expression
	 */
	error = 0;
	for(fs=filsys; fs->name; fs++) {
		print("filsys %s %s\n", fs->name, fs->conf);
		fs->dev = iconfig(fs->conf);
		if(f.error) {
			error = 1;
			continue;
		}
	}
	if(error)
		panic("fs config");

	/*
	 * part 4 -- initialize the devices
	 */
	for(fs=filsys; fs->name; fs++) {
		delay(3000);
		print("sysinit: %s\n", fs->name);
		if(fs->flags & FREAM)
			devream(fs->dev, 1);
		if(fs->flags & FRECOVER)
			devrecover(fs->dev);
		devinit(fs->dev);
	}

	floppyhalt();			/* don't wear out the floppy */
	if (copyworm) {
		dowormcopy();		/* can return if user quits early */
		panic("copyworm bailed out!");
	}
	if (copydev)
		if (dodevcopy() < 0)
			panic("copydev failed!");
		else
			panic("copydev done.");
}

/* an unfinished idea.  a non-blocking rawchar() would help. */
static int
userabort(char *msg)
{
#ifdef IdeaIsFinished
	if (consgetcifany() == 'q') {
		print("aborting %s\n", msg);
		return 1;
	}
#else
	USED(msg);
#endif /* IdeaIsFinished */
	return 0;
}

static int
blockok(Device *d, Off a)
{
	Iobuf *p = getbuf(d, a, Bread);

	if (p == 0) {
		print("i/o error reading %Z block %lld\n", d, (Wideoff)a);
		return 0;
	}
	putbuf(p);
	return 1;
}

/*
 * special case for fake worms only:
 * we need to size the inner cw's worm device.
 * in particular, we want to avoid copying the fake-worm bitmap
 * at the end of the device.
 *
 * N.B.: for real worms (e.g. cw jukes), we need to compute devsize(cw(juke)),
 * *NOT* devsize(juke).
 */
static Device *
wormof(Device *dev)
{
	Device *worm = dev, *cw;

	if (dev->type == Devfworm) {
		cw = dev->fw.fw;
		if (cw != nil && cw->type == Devcw)
			worm = cw->cw.w;
	}
	// print("wormof(%Z)=%Z\n", dev, worm);
	return worm;
}

/*
 * return the number of the highest-numbered block actually written, plus 1.
 * 0 indicates an error.
 */
static Devsize
writtensize(Device *worm)
{
	Devsize lim = devsize(worm);
	Iobuf *p;

	print("devsize(%Z) = %lld\n", worm, (Wideoff)lim);
	if (!blockok(worm, 0) || !blockok(worm, lim-1))
		return 0;
	delay(5*1000);
	if (userabort("sanity checks"))
		return 0;

	/* find worm's last valid block in case "worm" is an (f)worm */
	while (lim > 0) {
		if (userabort("sizing")) {
			lim = 0;		/* you lose */
			break;
		}
		--lim;
		p = getbuf(worm, lim, Bread);
		if (p != 0) {			/* actually read one okay? */
			putbuf(p);
			break;
		}
	}
	print("limit(%Z) = %lld\n", worm, (Wideoff)lim);
	return lim <= 0? 0: lim + 1;
}

/* copy worm fs from "main"'s inner worm to "output" */
static void
dowormcopy(void)
{
	Filsys *f1, *f2;
	Device *fdev, *from, *to = nil;
	Iobuf *p;
	Off a;
	Devsize lim;

	/*
	 * convert file system names into Filsyss and Devices.
	 */

	f1 = fsstr("main");
	if(f1 == nil)
		panic("main file system missing");
	fdev = f1->dev;
	from = wormof(fdev);			/* fake worm special */
	if (from->type != Devfworm && from->type != Devcw) {
		print("main file system is not a worm; copyworm may not do what you want!\n");
		print("waiting for 20 seconds...\n");
		delay(20000);
	}

	f2 = fsstr("output");
	if(f2 == nil) {
		print("no output file system - check only\n\n");
		print("reading worm from %Z (worm %Z)\n", fdev, from);
	} else {
		to = f2->dev;
		print("\ncopying worm from %Z (worm %Z) to %Z, starting in 8 seconds\n",
			fdev, from, to);
		delay(8000);
	}
	if (userabort("preparing to copy"))
		return;

	/*
	 * initialise devices, size them, more sanity checking.
	 */

	devinit(from);
	if (0 && fdev != from) {
		devinit(fdev);
		print("debugging, sizing %Z first\n", fdev);
		writtensize(fdev);
	}
	lim = writtensize(from);
	if(lim == 0)
		panic("no blocks to copy on %Z", from);
	if (to) {
		print("reaming %Z in 8 seconds\n", to);
		delay(8000);
		if (userabort("preparing to ream & copy"))
			return;
		devream(to, 0);
		devinit(to);
		print("copying worm: %lld blocks from %Z to %Z\n",
			(Wideoff)lim, from, to);
	}
	/* can't read to's blocks in case to is a real WORM device */

	/*
	 * Copy written fs blocks, a block at a time (or just read
	 * if no "output" fs).
	 */

	for (a = 0; a < lim; a++) {
		if (userabort("copy"))
			break;
		p = getbuf(from, a, Bread);
		/*
		 * if from is a real WORM device, we'll get errors trying to
		 * read unwritten blocks, but the unwritten blocks need not
		 * be contiguous.
		 */
		if (p == 0) {
			print("%lld not written yet; can't read\n", (Wideoff)a);
			continue;
		}
		if (to != 0 && devwrite(to, p->addr, p->iobuf) != 0) {
			print("out block %lld: write error; bailing",
				(Wideoff)a);
			break;
		}
		putbuf(p);
		if(a % 20000 == 0)
			print("block %lld %T\n", (Wideoff)a, time());
	}

	/*
	 * wrap up: sync target, loop
	 */
	print("copied %lld blocks from %Z to %Z\n", (Wideoff)a, from, to);
	sync("wormcopy");
	delay(2000);
	print("looping; reset the machine at any time.\n");
	for (; ; )
		continue;		/* await reset */
}

/* copy device from src to dest */
static int
dodevcopy(void)
{
	Device *from, *to;
	Iobuf *p;
	Off a;
	Devsize lim, tosize;

	/*
	 * convert config strings into Devices.
	 */
	from = iconfig(src);
	if(f.error || from == nil) {
		print("bad src device %s\n", src);
		return -1;
	}
	to = iconfig(dest);
	if(f.error || to == nil) {
		print("bad dest device %s\n", dest);
		return -1;
	}

	/*
	 * initialise devices, size them, more sanity checking.
	 */

	devinit(from);
	lim = devsize(from);
	if(lim == 0)
		panic("no blocks to copy on %Z", from);
	devinit(to);
	tosize = devsize(to);
	if(tosize == 0)
		panic("no blocks to copy on %Z", to);

	/* use smaller of the device sizes */
	if (tosize < lim)
		lim = tosize;

	print("copy %Z to %Z in 8 seconds\n", from, to);
	delay(8000);
	if (userabort("preparing to copy"))
		return -1;
	print("copying dev: %lld blocks from %Z to %Z\n", (Wideoff)lim,
		from, to);

	/*
	 * Copy all blocks, a block at a time.
	 */

	for (a = 0; a < lim; a++) {
		if (userabort("copy"))
			break;
		p = getbuf(from, a, Bread);
		/*
		 * if from is a real WORM device, we'll get errors trying to
		 * read unwritten blocks, but the unwritten blocks need not
		 * be contiguous.
		 */
		if (p == 0) {
			print("%lld not written yet; can't read\n", (Wideoff)a);
			continue;
		}
		if (to != 0 && devwrite(to, p->addr, p->iobuf) != 0) {
			print("out block %lld: write error; bailing",
				(Wideoff)a);
			break;
		}
		putbuf(p);
		if(a % 20000 == 0)
			print("block %lld %T\n", (Wideoff)a, time());
	}

	/*
	 * wrap up: sync target
	 */
	print("copied %lld blocks from %Z to %Z\n", (Wideoff)a, from, to);
	sync("devcopy");
	return 0;
}

void
getline(char *line)
{
	char *p;
	int c;

	p = line;
	for(;;) {
		c = rawchar(0);
		if(c == 0 || c == '\n') {
			*p = 0;
			return;
		}
		if(c == '\b') {
			p--;
			continue;
		}
		*p++ = c;
	}
}

void
arginit(void)
{
	int verb, c;
	char line[2*Maxword], word[Maxword+1], *cp;
	uchar localip[Pasize];
	Filsys *fs;

	if(nvrcheck() == 0){
		print("for config mode hit a key within 5 seconds\n");
		c = rawchar(5);
		if(c == 0) {
			print("	no config\n");
			return;
		}
	}

	for (;;) {
		print("config: ");
		getline(line);
		cp = getwd(word, line);
		if (word[0] == '\0' || word[0] == '#')
			continue;
		if(strcmp(word, "end") == 0)
			return;
		if(strcmp(word, "halt") == 0) {
			floppyhalt();
			exit();
		}

		if(strcmp(word, "allow") == 0) {
			wstatallow = 1;
			writeallow = 1;
			continue;
		}
		if(strcmp(word, "copyworm") == 0) {
			copyworm = 1;
			continue;
		}
		if(strcmp(word, "copydev") == 0) {	/* not yet documented */
			cp = getwd(word, cp);
			if(testconfig(word))
				continue;
			src = strdup(word);
			getwd(word, cp);
			if(testconfig(word))
				continue;
			dest = strdup(word);
			copydev = 1;
			continue;
		}
		if(strcmp(word, "noauth") == 0) {
			noauth = !noauth;
			continue;
		}
		if(strcmp(word, "noattach") == 0) {
			noattach = !noattach;
			continue;
		}
		if(strcmp(word, "readonly") == 0) {
			readonly = 1;
			continue;
		}

		if(strcmp(word, "ream") == 0) {
			verb = FREAM;
			goto gfsname;
		}
		if(strcmp(word, "recover") == 0) {
			verb = FRECOVER;
			goto gfsname;
		}
		if(strcmp(word, "filsys") == 0) {
			verb = FEDIT;
			goto gfsname;
		}

		if(strcmp(word, "nvram") == 0) {
			getwd(word, cp);
			if(testconfig(word))
				continue;
			/* if it fails, it will complain */
			nvrsetconfig(word);
			continue;
		}
		if(strcmp(word, "config") == 0) {
			getwd(word, cp);
			if(!testconfig(word) && nvrsetconfig(word) == 0)
				f.newconf = 1;
			continue;
		}
		if(strcmp(word, "service") == 0) {
			getwd(word, cp);
			strcpy(service, word);
			f.modconf = 1;
			continue;
		}

		if(strcmp(word, "ipauth") == 0) {
			f.ipauthset = 1;
			verb = 2;
		} else if(astrcmp(word, "ip") == 0)
			verb = 0;
		else if(astrcmp(word, "ipgw") == 0)
			verb = 1;
		else if(astrcmp(word, "ipmask") == 0)
			verb = 3;
		else if(astrcmp(word, "ipsntp") == 0)
			verb = 4;
		else {
			print("unknown config command\n");
			print("	type end to get out\n");
			continue;
		}

		getwd(word, cp);
		if(chartoip(localip, word)) {
			print("bad ip address\n");
			continue;
		}
		switch(verb) {
		case 0:
			memmove(ipaddr[aindex].sysip, localip,
				sizeof(ipaddr[aindex].sysip));
			break;
		case 1:
			memmove(ipaddr[aindex].defgwip, localip,
				sizeof(ipaddr[aindex].defgwip));
			break;
		case 2:
			memmove(authip, localip, sizeof(authip));
			break;
		case 3:
			memmove(ipaddr[aindex].defmask, localip,
				sizeof(ipaddr[aindex].defmask));
			break;
		case 4:
			memmove(sntpip, localip, sizeof(sntpip));
			break;
		}
		f.modconf = 1;
		continue;

	gfsname:
		cp = getwd(word, cp);
		for(fs=filsys; fs->name; fs++)
			if(strcmp(word, fs->name) == 0)
				break;
		if (fs->name == nil) {
			memset(fs, 0, sizeof(*fs));
			fs->name = strdup(word);
		}
		switch(verb) {
		case FREAM:
			if(strcmp(fs->name, "main") == 0)
				wstatallow = 1;	/* only set, never reset */
		case FRECOVER:
			fs->flags |= verb;
			break;
		case FEDIT:
			f.modconf = 1;
			getwd(word, cp);
			fs->flags |= verb;
			if(word[0] == 0)
				fs->conf = nil;
			else if(!testconfig(word))
				fs->conf = strdup(word);
			break;
		}
	}
}