tar.c

unix v7是最后一个广泛发布的研究型UNIX版本

		}

		checkdir(dblock.dbuf.name);

		if (dblock.dbuf.linkflag == '1') {
			unlink(dblock.dbuf.name);
			if (link(dblock.dbuf.linkname, dblock.dbuf.name) < 0) {
				fprintf(stderr, "%s: cannot link\n", dblock.dbuf.name);
				continue;
			}
			if (vflag)
				fprintf(stderr, "%s linked to %s\n", dblock.dbuf.name, dblock.dbuf.linkname);
			continue;
		}
		if ((ofile = creat(dblock.dbuf.name, stbuf.st_mode & 07777)) < 0) {
			fprintf(stderr, "tar: %s - cannot create\n", dblock.dbuf.name);
			passtape();
			continue;
		}

		chown(dblock.dbuf.name, stbuf.st_uid, stbuf.st_gid);

		blocks = ((bytes = stbuf.st_size) + TBLOCK-1)/TBLOCK;
		if (vflag)
			fprintf(stderr, "x %s, %ld bytes, %ld tape blocks\n", dblock.dbuf.name, bytes, blocks);
		while (blocks-- > 0) {
			readtape(buf);
			if (bytes > TBLOCK) {
				if (write(ofile, buf, TBLOCK) < 0) {
					fprintf(stderr, "tar: %s: HELP - extract write error\n", dblock.dbuf.name);
					done(2);
				}
			} else
				if (write(ofile, buf, (int) bytes) < 0) {
					fprintf(stderr, "tar: %s: HELP - extract write error\n", dblock.dbuf.name);
					done(2);
				}
			bytes -= TBLOCK;
		}
		close(ofile);
		if (mflag == 0) {
			time_t timep[2];

			timep[0] = time(NULL);
			timep[1] = stbuf.st_mtime;
			utime(dblock.dbuf.name, timep);
		}
	}
}

dotable()
{
	for (;;) {
		getdir();
		if (endtape())
			break;
		if (vflag)
			longt(&stbuf);
		printf("%s", dblock.dbuf.name);
		if (dblock.dbuf.linkflag == '1')
			printf(" linked to %s", dblock.dbuf.linkname);
		printf("\n");
		passtape();
	}
}

putempty()
{
	char buf[TBLOCK];
	char *cp;

	for (cp = buf; cp < &buf[TBLOCK]; )
		*cp++ = '\0';
	writetape(buf);
}

longt(st)
register struct stat *st;
{
	register char *cp;
	char *ctime();

	pmode(st);
	printf("%3d/%1d", st->st_uid, st->st_gid);
	printf("%7D", st->st_size);
	cp = ctime(&st->st_mtime);
	printf(" %-12.12s %-4.4s ", cp+4, cp+20);
}

#define	SUID	04000
#define	SGID	02000
#define	ROWN	0400
#define	WOWN	0200
#define	XOWN	0100
#define	RGRP	040
#define	WGRP	020
#define	XGRP	010
#define	ROTH	04
#define	WOTH	02
#define	XOTH	01
#define	STXT	01000
int	m1[] = { 1, ROWN, 'r', '-' };
int	m2[] = { 1, WOWN, 'w', '-' };
int	m3[] = { 2, SUID, 's', XOWN, 'x', '-' };
int	m4[] = { 1, RGRP, 'r', '-' };
int	m5[] = { 1, WGRP, 'w', '-' };
int	m6[] = { 2, SGID, 's', XGRP, 'x', '-' };
int	m7[] = { 1, ROTH, 'r', '-' };
int	m8[] = { 1, WOTH, 'w', '-' };
int	m9[] = { 2, STXT, 't', XOTH, 'x', '-' };

int	*m[] = { m1, m2, m3, m4, m5, m6, m7, m8, m9};

pmode(st)
register struct stat *st;
{
	register int **mp;

	for (mp = &m[0]; mp < &m[9];)
		select(*mp++, st);
}

select(pairp, st)
int *pairp;
struct stat *st;
{
	register int n, *ap;

	ap = pairp;
	n = *ap++;
	while (--n>=0 && (st->st_mode&*ap++)==0)
		ap++;
	printf("%c", *ap);
}

checkdir(name)
register char *name;
{
	register char *cp;
	int i;
	for (cp = name; *cp; cp++) {
		if (*cp == '/') {
			*cp = '\0';
			if (access(name, 01) < 0) {
				if (fork() == 0) {
					execl("/bin/mkdir", "mkdir", name, 0);
					execl("/usr/bin/mkdir", "mkdir", name, 0);
					fprintf(stderr, "tar: cannot find mkdir!\n");
					done(0);
				}
				while (wait(&i) >= 0);
				chown(name, stbuf.st_uid, stbuf.st_gid);
			}
			*cp = '/';
		}
	}
}

onintr()
{
	signal(SIGINT, SIG_IGN);
	term++;
}

onquit()
{
	signal(SIGQUIT, SIG_IGN);
	term++;
}

onhup()
{
	signal(SIGHUP, SIG_IGN);
	term++;
}

onterm()
{
	signal(SIGTERM, SIG_IGN);
	term++;
}

tomodes(sp)
register struct stat *sp;
{
	register char *cp;

	for (cp = dblock.dummy; cp < &dblock.dummy[TBLOCK]; cp++)
		*cp = '\0';
	sprintf(dblock.dbuf.mode, "%6o ", sp->st_mode & 07777);
	sprintf(dblock.dbuf.uid, "%6o ", sp->st_uid);
	sprintf(dblock.dbuf.gid, "%6o ", sp->st_gid);
	sprintf(dblock.dbuf.size, "%11lo ", sp->st_size);
	sprintf(dblock.dbuf.mtime, "%11lo ", sp->st_mtime);
}

checksum()
{
	register i;
	register char *cp;

	for (cp = dblock.dbuf.chksum; cp < &dblock.dbuf.chksum[sizeof(dblock.dbuf.chksum)]; cp++)
		*cp = ' ';
	i = 0;
	for (cp = dblock.dummy; cp < &dblock.dummy[TBLOCK]; cp++)
		i += *cp;
	return(i);
}

checkw(c, name)
char *name;
{
	if (wflag) {
		printf("%c ", c);
		if (vflag)
			longt(&stbuf);
		printf("%s: ", name);
		if (response() == 'y'){
			return(1);
		}
		return(0);
	}
	return(1);
}

response()
{
	char c;

	c = getchar();
	if (c != '\n')
		while (getchar() != '\n');
	else c = 'n';
	return(c);
}

checkupdate(arg)
char	*arg;
{
	char name[100];
	long	mtime;
	daddr_t seekp;
	daddr_t	lookup();

	rewind(tfile);
	for (;;) {
		if ((seekp = lookup(arg)) < 0)
			return(1);
		fseek(tfile, seekp, 0);
		fscanf(tfile, "%s %lo", name, &mtime);
		if (stbuf.st_mtime > mtime)
			return(1);
		else
			return(0);
	}
}

done(n)
{
	unlink(tname);
	exit(n);
}

prefix(s1, s2)
register char *s1, *s2;
{
	while (*s1)
		if (*s1++ != *s2++)
			return(0);
	if (*s2)
		return(*s2 == '/');
	return(1);
}

getwdir(s)
char *s;
{
	int i;
	int	pipdes[2];

	pipe(pipdes);
	if ((i = fork()) == 0) {
		close(1);
		dup(pipdes[1]);
		execl("/bin/pwd", "pwd", 0);
		execl("/usr/bin/pwd", "pwd", 0);
		fprintf(stderr, "pwd failed!\n");
		printf("/\n");
		exit(1);
	}
	while (wait((int *)NULL) != -1)
			;
	read(pipdes[0], s, 50);
	while(*s != '\n')
		s++;
	*s = '\0';
	close(pipdes[0]);
	close(pipdes[1]);
}

#define	N	200
int	njab;
daddr_t
lookup(s)
char *s;
{
	register i;
	daddr_t a;

	for(i=0; s[i]; i++)
		if(s[i] == ' ')
			break;
	a = bsrch(s, i, low, high);
	return(a);
}

daddr_t
bsrch(s, n, l, h)
daddr_t l, h;
char *s;
{
	register i, j;
	char b[N];
	daddr_t m, m1;

	njab = 0;

loop:
	if(l >= h)
		return(-1L);
	m = l + (h-l)/2 - N/2;
	if(m < l)
		m = l;
	fseek(tfile, m, 0);
	fread(b, 1, N, tfile);
	njab++;
	for(i=0; i<N; i++) {
		if(b[i] == '\n')
			break;
		m++;
	}
	if(m >= h)
		return(-1L);
	m1 = m;
	j = i;
	for(i++; i<N; i++) {
		m1++;
		if(b[i] == '\n')
			break;
	}
	i = cmp(b+j, s, n);
	if(i < 0) {
		h = m;
		goto loop;
	}
	if(i > 0) {
		l = m1;
		goto loop;
	}
	return(m);
}

cmp(b, s, n)
char *b, *s;
{
	register i;

	if(b[0] != '\n')
		exit(2);
	for(i=0; i<n; i++) {
		if(b[i+1] > s[i])
			return(-1);
		if(b[i+1] < s[i])
			return(1);
	}
	return(b[i+1] == ' '? 0 : -1);
}

readtape(buffer)
char *buffer;
{
	int i, j;

	if (recno >= nblock || first == 0) {
		if (first == 0 && nblock == 0)
			j = NBLOCK;
		else
			j = nblock;
		if ((i = read(mt, tbuf, TBLOCK*j)) < 0) {
			fprintf(stderr, "Tar: tape read error\n");
			done(3);
		}
		if (first == 0) {
			if ((i % TBLOCK) != 0) {
				fprintf(stderr, "Tar: tape blocksize error\n");
				done(3);
			}
			i /= TBLOCK;
			if (rflag && i != 1) {
				fprintf(stderr, "Tar: Cannot update blocked tapes (yet)\n");
				done(4);
			}
			if (i != nblock && i != 1) {
				fprintf(stderr, "Tar: blocksize = %d\n", i);
				nblock = i;
			}
		}
		recno = 0;
	}
	first = 1;
	copy(buffer, &tbuf[recno++]);
	return(TBLOCK);
}

writetape(buffer)
char *buffer;
{
	first = 1;
	if (nblock == 0)
		nblock = 1;
	if (recno >= nblock) {
		if (write(mt, tbuf, TBLOCK*nblock) < 0) {
			fprintf(stderr, "Tar: tape write error\n");
			done(2);
		}
		recno = 0;
	}
	copy(&tbuf[recno++], buffer);
	if (recno >= nblock) {
		if (write(mt, tbuf, TBLOCK*nblock) < 0) {
			fprintf(stderr, "Tar: tape write error\n");
			done(2);
		}
		recno = 0;
	}
	return(TBLOCK);
}

backtape()
{
	lseek(mt, (long) -TBLOCK, 1);
	if (recno >= nblock) {
		recno = nblock - 1;
		if (read(mt, tbuf, TBLOCK*nblock) < 0) {
			fprintf(stderr, "Tar: tape read error after seek\n");
			done(4);
		}
		lseek(mt, (long) -TBLOCK, 1);
	}
}

flushtape()
{
	write(mt, tbuf, TBLOCK*nblock);
}

copy(to, from)
register char *to, *from;
{
	register i;

	i = TBLOCK;
	do {
		*to++ = *from++;
	} while (--i);
}