fsck1.c

操作系统源代码

  if ((short) sb.s_firstdatazone <= 1) fatal("first data zone too small");
  if ((short) sb.s_log_zone_size < 0) fatal("zone size < block size");
  if (sb.s_max_size <= 0) fatal("max. file size <= 0");
}

/* Check the super block for reasonable contents. */
void chksuper()
{
  register n;
  register off_t maxsize;

  n = bitmapsize((bit_t) sb.s_ninodes + 1);
  if (sb.s_magic != SUPER_MAGIC) fatal("bad magic number in super block");
  if ((short) sb.s_imap_blocks < n) fatal("too few imap blocks");
  if (sb.s_imap_blocks != n) {
	pr("warning: expected %d imap_block%s", n, "", "s");
	printf(" instead of %d\n", sb.s_imap_blocks);
  }
  n = bitmapsize((bit_t) sb.s_nzones);
  if ((short) sb.s_zmap_blocks < n) fatal("too few zmap blocks");
  if (sb.s_zmap_blocks != n) {
	pr("warning: expected %d zmap_block%s", n, "", "s");
	printf(" instead of %d\n", sb.s_zmap_blocks);
  }
  if (sb.s_firstdatazone >= sb.s_nzones)
	fatal("first data zone too large");
  if ((unsigned short) sb.s_log_zone_size >= 8 * sizeof(block_nr))
	fatal("log_zone_size too large");
  if (sb.s_log_zone_size > 8) printf("warning: large log_zone_size (%d)\n",
	       sb.s_log_zone_size);
  n = (BLK_ILIST + N_ILIST + SCALE - 1) >> sb.s_log_zone_size;
  if ((short) sb.s_firstdatazone < n) fatal("first data zone too small");
  if (sb.s_firstdatazone != n) {
	printf("warning: expected first data zone to be %d ", n);
	printf("instead of %u\n", sb.s_firstdatazone);
  }
  maxsize = MAX_FILE_POS;
  if (((maxsize - 1) >> sb.s_log_zone_size) / BLOCK_SIZE >= MAX_ZONES)
	maxsize = ((long) MAX_ZONES * BLOCK_SIZE) << sb.s_log_zone_size;
  if (sb.s_max_size != maxsize) {
	printf("warning: expected max size to be %ld ", maxsize);
	printf("instead of %ld\n", sb.s_max_size);
  }
}

/* Make a listing of the inodes given by `clist'.  If `repair' is set, ask
 * the user for changes.
 */
void lsi(clist)
char **clist;
{
  register bit_nr bit;
  register ino_t ino;
  d_inode inode, *ip = &inode;
  char buf[80];

  if (clist == 0) return;
  while ((bit = getnumber(*clist++)) != NO_BIT) {
	setbit(spec_imap, bit);
	ino = bit;
	do {
		devread(inoaddr(ino), (char *) ip, INODE_SIZE);
		printf("inode %u:\n", ino);
		printf("    mode   = %06o", ip->i_mode);
		if (input(buf, 80)) ip->i_mode = atoo(buf);
		printf("    nlinks = %6u", ip->i_nlinks);
		if (input(buf, 80)) ip->i_nlinks = atol(buf);
		printf("    size   = %6ld", ip->i_size);
		if (input(buf, 80)) ip->i_size = atol(buf);
		if (yes("Write this back")) {
			devwrite(inoaddr(ino), (char *) ip, INODE_SIZE);
			break;
		}
	} while (yes("Do you want to change it again"));
  }
}

/* Allocate `nblk' blocks worth of bitmap. */
bitchunk_t *allocbitmap(nblk)
int nblk;
{
  register bitchunk_t *bitmap;

  bitmap = (bitchunk_t *) alloc(nblk, BLOCK_SIZE);
  *bitmap |= 1;
  return(bitmap);
}

/* Load the bitmap starting at block `bno' from disk. */
void loadbitmap(bitmap, bno, nblk)
bitchunk_t *bitmap;
block_nr bno;
int nblk;
{
  register i;
  register bitchunk_t *p;

  p = bitmap;
  for (i = 0; i < nblk; i++, bno++, p += WORDS_PER_BLOCK)
	devread(btoa(bno), (char *) p, BLOCK_SIZE);
  *bitmap |= 1;
}

/* Write the bitmap starting at block `bno' to disk. */
void dumpbitmap(bitmap, bno, nblk)
bitchunk_t *bitmap;
block_nr bno;
int nblk;
{
  register i;
  register bitchunk_t *p = bitmap;

  for (i = 0; i < nblk; i++, bno++, p += WORDS_PER_BLOCK)
	devwrite(btoa(bno), (char *) p, BLOCK_SIZE);
}

/* Set the bits given by `list' in the bitmap. */
void fillbitmap(bitmap, lwb, upb, list)
bitchunk_t *bitmap;
bit_nr lwb, upb;
char **list;
{
  register bit_nr bit;

  if (list == 0) return;
  while ((bit = getnumber(*list++)) != NO_BIT)
	if (bit < lwb || bit >= upb) {
		if (bitmap == spec_imap)
			printf("inode number %u ", bit);
		else
			printf("zone number %u ", bit);
		printf("out of range (ignored)\n");
	} else
		setbit(bitmap, bit - lwb + 1);
}

/* Deallocate the bitmap `p'. */
void freebitmap(p)
bitchunk_t *p;
{
  free((char *) p);
}

/* Get all the bitmaps used by this program. */
void getbitmaps()
{
  imap = allocbitmap(N_IMAP);
  zmap = allocbitmap(N_ZMAP);
  spec_imap = allocbitmap(N_IMAP);
  spec_zmap = allocbitmap(N_ZMAP);
  dirmap = allocbitmap(N_IMAP);
}

/* Release all the space taken by the bitmaps. */
void putbitmaps()
{
  freebitmap(imap);
  freebitmap(zmap);
  freebitmap(spec_imap);
  freebitmap(spec_zmap);
  freebitmap(dirmap);
}

/* `w1' and `w2' are differing words from two bitmaps that should be
 * identical.  Print what's the matter with them.
 */
void chkword(w1, w2, bit, type, n, report)
unsigned w1, w2;
char *type;
bit_nr bit;
int *n, *report;
{
  for (; (w1 | w2); w1 >>= 1, w2 >>= 1, bit++)
	if ((w1 ^ w2) & 1 && ++(*n) % MAXPRINT == 0 && *report &&
	    (!repair || automatic || yes("stop this listing")))
		*report = 0;
	else if (*report)
		if ((w1 & 1) && !(w2 & 1))
			printf("%s %u is missing\n", type, bit);
		else if (!(w1 & 1) && (w2 & 1))
			printf("%s %u is not free\n", type, bit);
}

/* Check if the given (correct) bitmap is identical with the one that is
 * on the disk.  If not, ask if the disk should be repaired.
 */
void chkmap(cmap, dmap, bit, blkno, nblk, type)
bitchunk_t *cmap, *dmap;
bit_nr bit;
block_nr blkno;
int nblk;
char *type;
{
  register bitchunk_t *p = dmap, *q = cmap;
  int report = 1, nerr = 0;
  int w = nblk * WORDS_PER_BLOCK;

  printf("Checking %s map\n", type);
  loadbitmap(dmap, blkno, nblk);
  do {
	if (*p != *q) chkword(*p, *q, bit, type, &nerr, &report);
	p++;
	q++;
	bit += 8 * sizeof(bitchunk_t);
  } while (--w > 0);

  if ((!repair || automatic) && !report) printf("etc. ");
  if (nerr > MAXPRINT || nerr > 10) printf("%d errors found. ", nerr);
  if (nerr != 0 && yes("install a new map")) dumpbitmap(cmap, blkno, nblk);
  if (nerr > 0) printf("\n");
}

/* See if the inodes that aren't allocated are cleared. */
void chkilist()
{
  register ino_t ino = 1;
  mode_t mode;

  printf("Checking inode list\n");
  do
	if (!bitset(imap, (bit_nr) ino)) {
		devread(inoaddr(ino), (char *) &mode, sizeof(mode));
		if (mode != I_NOT_ALLOC) {
			printf("mode inode %u not cleared", ino);
			if (yes(". clear")) devwrite(inoaddr(ino), nullbuf,
					 INODE_SIZE);
		}
	}
  while (++ino <= sb.s_ninodes);
  printf("\n");
}

/* Allocate an array to maintain the inode reference counts in. */
void getcount()
{
  count = (nlink_t *) alloc(sb.s_ninodes + 1, sizeof(nlink_t));
}

/* The reference count for inode `ino' is wrong.  Ask if it should be adjusted. */
void counterror(ino)
ino_t ino;
{
  d_inode inode;

  if (firstcnterr) {
	printf("INODE NLINK COUNT\n");
	firstcnterr = 0;
  }
  devread(inoaddr(ino), (char *) &inode, INODE_SIZE);
  count[ino] += inode.i_nlinks;
  printf("%5u %5u %5u", ino, (unsigned) inode.i_nlinks, count[ino]);
  if (yes(" adjust")) {
	if ((inode.i_nlinks = count[ino]) == 0) {
		fatal("internal error (counterror)");
/* This would be a patch
		inode.i_mode = I_NOT_ALLOC;
		clrbit(imap, (bit_nr) ino);
*/
	}
	devwrite(inoaddr(ino), (char *) &inode, INODE_SIZE);
  }
}

/* Check if the reference count of the inodes are correct.  The array `count'
 * is maintained as follows:  an entry indexed by the inode number is
 * incremented each time a link is found; when the inode is read the link
 * count in there is substracted from the corresponding entry in `count'.
 * Thus, when the whole file system has been traversed, all the entries
 * should be zero.
 */
void chkcount()
{
  register ino_t ino;

  for (ino = 1; ino <= sb.s_ninodes; ino++)
	if (count[ino] != 0) counterror(ino);
  if (!firstcnterr) printf("\n");
}

/* Deallocate the `count' array. */
void freecount()
{
  free((char *) count);
}

/* Print the inode permission bits given by mode and shift. */
void printperm(mode, shift, special, overlay)
mode_t mode;
int shift;
int special;
int overlay;
{
  if (mode >> shift & R_BIT)
	putchar('r');
  else
	putchar('-');
  if (mode >> shift & W_BIT)
	putchar('w');
  else
	putchar('-');
  if (mode & special)
	putchar(overlay);
  else
	if (mode >> shift & X_BIT)
		putchar('x');
	else
		putchar('-');
}

/* List the given inode. */
void list(ino, ip)
ino_t ino;
d_inode *ip;
{
  if (firstlist) {
	firstlist = 0;
	printf(" inode permission link   size name\n");
  }
  printf("%6u ", ino);
  switch (ip->i_mode & I_TYPE) {
      case I_REGULAR:		putchar('-');	break;
      case I_DIRECTORY:		putchar('d');	break;
      case I_CHAR_SPECIAL:	putchar('c');	break;
      case I_BLOCK_SPECIAL:	putchar('b');	break;
      case I_NAMED_PIPE:	putchar('p');	break;
#ifdef I_SYMBOLIC_LINK
      case I_SYMBOLIC_LINK:	putchar('l');	break;
#endif
      default:			putchar('?');
}
  printperm(ip->i_mode, 6, I_SET_UID_BIT, 's');
  printperm(ip->i_mode, 3, I_SET_GID_BIT, 's');
  printperm(ip->i_mode, 0, STICKY_BIT, 't');
  printf(" %3u ", ip->i_nlinks);
  switch (ip->i_mode & I_TYPE) {
      case I_CHAR_SPECIAL:
      case I_BLOCK_SPECIAL:
	printf("  %2x,%2x ", (dev_t) ip->i_zone[0] >> MAJOR & 0xFF,
	       (dev_t) ip->i_zone[0] >> MINOR & 0xFF);
	break;
      default:	printf("%7ld ", ip->i_size);
  }
  printpath(0, 1);
}

/* Remove an entry from a directory if ok with the user.
 * Don't name the function remove() - that is owned by ANSI, and chaos results
 * when it is a macro.
 */
int Remove(dp)
dir_struct *dp;
{
  setbit(spec_imap, (bit_nr) dp->d_inum);
  if (yes(". remove entry")) {
	count[dp->d_inum]--;
	memset((void *) dp, 0, sizeof(dir_struct));
	return(1);
  }
  return(0);
}

/* Convert string so that embedded control characters are printable. */
void make_printable_name(dst, src, n)
register char *dst;
register char *src;
register int n;
{
  register int c;

  while (--n >= 0 && (c = *src++) != '\0') {
	if (isprint(c) && c != '\\')
		*dst++ = c;
	else {
		*dst++ = '\\';
		switch (c) {
		      case '\\':
			*dst++ = '\\'; break;
		      case '\b':
			*dst++ = 'b'; break;
		      case '\f':
			*dst++ = 'f'; break;
		      case '\n':
			*dst++ = 'n'; break;
		      case '\r':
			*dst++ = 'r'; break;
		      case '\t':
			*dst++ = 't'; break;
		      default:
			*dst++ = '0' + ((c >> 6) & 03);
			*dst++ = '0' + ((c >> 3) & 07);
			*dst++ = '0' + (c & 07);
		}
	}
  }
  *dst = '\0';
}

/* See if the `.' or `..' entry is as expected. */
int chkdots(ino, pos, dp, exp)
ino_t ino, exp;
off_t pos;
dir_struct *dp;
{
  char printable_name[4 * NAME_MAX + 1];

  if (dp->d_inum != exp) {
	make_printable_name(printable_name, dp->d_name, sizeof(dp->d_name));
	printf("bad %s in ", printable_name);
	printpath(1, 0);
	printf("%s is linked to %u ", printable_name, dp->d_inum);
	printf("instead of %u)", exp);
	setbit(spec_imap, (bit_nr) ino);
	setbit(spec_imap, (bit_nr) dp->d_inum);
	setbit(spec_imap, (bit_nr) exp);
	if (yes(". repair")) {
		count[dp->d_inum]--;
		dp->d_inum = exp;
		count[exp]++;
		return(0);
	}
  } else if (pos != (dp->d_name[1] ? DIR_ENTRY_SIZE : 0)) {
	make_printable_name(printable_name, dp->d_name, sizeof(dp->d_name));
	printf("warning: %s has offset %ld in ", printable_name, pos);
	printpath(1, 0);
	printf("%s is linked to %u)\n", printable_name, dp->d_inum);
	setbit(spec_imap, (bit_nr) ino);
	setbit(spec_imap, (bit_nr) dp->d_inum);
	setbit(spec_imap, (bit_nr) exp);
  }
  return(1);
}

/* Check the name in a directory entry. */
int chkname(ino, dp)
ino_t ino;
dir_struct *dp;
{
  register n = NAME_MAX + 1;
  register char *p = dp->d_name;

  if (*p == '\0') {
	printf("null name found in ");
	printpath(0, 0);
	setbit(spec_imap, (bit_nr) ino);
	if (Remove(dp)) return(0);
  }
  while (*p != '\0' && --n != 0)
	if (*p++ == '/') {
		printf("found a '/' in entry of directory ");
		printpath(1, 0);
		setbit(spec_imap, (bit_nr) ino);
		printf("entry = '");
		printname(dp->d_name);
		printf("')");
		if (Remove(dp)) return(0);
		break;
	}
  return(1);
}

/* Check a directory entry.  Here the routine `descendtree' is called
 * recursively to check the file or directory pointed to by the entry.
 */
int chkentry(ino, pos, dp)
ino_t ino;
off_t pos;
dir_struct *dp;
{
  if (dp->d_inum < ROOT_INODE || dp->d_inum > sb.s_ninodes) {
	printf("bad inode found in directory ");
	printpath(1, 0);
	printf("ino found = %u, ", dp->d_inum);
	printf("name = '");
	printname(dp->d_name);
	printf("')");
	if (yes(". remove entry")) {
		memset((void *) dp, 0, sizeof(dir_struct));
		return(0);
	}
	return(1);
  }
  if ((unsigned) count[dp->d_inum] == LINK_MAX) {
	printf("too many links to ino %u\n", dp->d_inum);
	printf("discovered at entry '");
	printname(dp->d_name);
	printf("' in directory ");
	printpath(0, 1);
	if (Remove(dp)) return(0);
  }
  count[dp->d_inum]++;
  if (strcmp(dp->d_name, ".") == 0) {
	ftop->st_presence |= DOT;
	return(chkdots(ino, pos, dp, ino));
  }
  if (strcmp(dp->d_name, "..") == 0) {
	ftop->st_presence |= DOTDOT;