mkfs.c

操作系统源代码

	if (*p == 'd') {
		/* This is a directory. */
		z = alloc_zone();	/* zone for new directory */
		add_zone(n, z, 32L, current_time);
		enter_dir(n, ".", n);
		enter_dir(n, "..", parent);
		incr_link(parent);
		incr_link(n);
		eat_dir(n);
	} else if (*p == 'b' || *p == 'c') {
		/* Special file. */
		maj = atoi(token[4]);
		min = atoi(token[5]);
		size = 0;
		if (token[6]) size = atoi(token[6]);
		size = BLOCK_SIZE * size;
		add_zone(n, (zone_t) ((maj << 8) | min), size, current_time);
	} else {
		/* Regular file. Go read it. */
		if ((f = open(token[4], O_RDONLY)) < 0) {
			fprintf(stderr, "%s: Can't open %s: %s\n",
				progname, token[4], strerror(errno));
		} else
			eat_file(n, f);
	}
  }

}

/*================================================================
 * 		eat_file  -  copy file to MINIX
 *===============================================================*/
/* Zonesize >= blocksize */
void eat_file(inode, f)
ino_t inode;
int f;
{
  int ct, i, j, k;
  zone_t z;
  char buf[BLOCK_SIZE];
  long timeval;

  do {
	for (i = 0, j = 0; i < zone_size; i++, j += ct) {
		for (k = 0; k < BLOCK_SIZE; k++) buf[k] = 0;
		if ((ct = read(f, buf, BLOCK_SIZE)) > 0) {
			if (i == 0) z = alloc_zone();
			put_block((z << zone_shift) + i, buf);
		}
	}
	timeval = (dflag ? current_time : file_time(f));
	if (ct) add_zone(inode, z, (long) j, timeval);
  } while (ct == BLOCK_SIZE);
  close(f);
}



/*================================================================
 *	    directory & inode management assist group
 *===============================================================*/
void enter_dir(parent, name, child)
ino_t parent, child;
char *name;
{
  /* Enter child in parent directory */
  /* Works for dir > 1 block and zone > block */
  int i, j, k, l, off;
  block_t b;
  zone_t z;
  char *p1, *p2;
  struct direct dir_entry[NR_DIR_ENTRIES];
  d1_inode ino1[V1_INODES_PER_BLOCK];
  d2_inode ino2[V2_INODES_PER_BLOCK];
  int nr_dzones;

  b = ((parent - 1) / inodes_per_block) + inode_offset;
  off = (parent - 1) % inodes_per_block;

  if (fs_version == 1) {
	get_block(b, (char *) ino1);
	nr_dzones = V1_NR_DZONES;
  } else {
	get_block(b, (char *) ino2);
	nr_dzones = V2_NR_DZONES;
  }
  for (k = 0; k < nr_dzones; k++) {
	if (fs_version == 1) {
		z = ino1[off].d1_zone[k];
		if (z == 0) {
			z = alloc_zone();
			ino1[off].d1_zone[k] = z;
		}
	} else {
		z = ino2[off].d2_zone[k];
		if (z == 0) {
			z = alloc_zone();
			ino2[off].d2_zone[k] = z;
		}
	}
	for (l = 0; l < zone_size; l++) {
		get_block((z << zone_shift) + l, (char *) dir_entry);
		for (i = 0; i < NR_DIR_ENTRIES; i++) {
			if (dir_entry[i].d_ino == 0) {
				dir_entry[i].d_ino = child;
				p1 = name;
				p2 = dir_entry[i].d_name;
				j = 14;
				while (j--) {
					*p2++ = *p1;
					if (*p1 != 0) p1++;
				}
				put_block((z << zone_shift) + l, (char *) dir_entry);
				if (fs_version == 1) {
					put_block(b, (char *) ino1);
				} else {
					put_block(b, (char *) ino2);
				}
				return;
			}
		}
	}
  }

  printf("Directory-inode %d beyond direct blocks.  Could not enter %s\n",
         parent, name);
  pexit("Halt");
}


void add_zone(n, z, bytes, cur_time)
ino_t n;
zone_t z;
long bytes, cur_time;
{
  if (fs_version == 1) {
	add_z_1(n, z, bytes, cur_time);
  } else {
	add_z_2(n, z, bytes, cur_time);
  }
}

void add_z_1(n, z, bytes, cur_time)
ino_t n;
zone_t z;
long bytes, cur_time;
{
  /* Add zone z to inode n. The file has grown by 'bytes' bytes. */

  int off, i;
  block_t b;
  zone_t indir;
  zone1_t blk[V1_INDIRECTS];
  d1_inode *p;
  d1_inode inode[V1_INODES_PER_BLOCK];

  b = ((n - 1) / V1_INODES_PER_BLOCK) + inode_offset;
  off = (n - 1) % V1_INODES_PER_BLOCK;
  get_block(b, (char *) inode);
  p = &inode[off];
  p->d1_size += bytes;
  p->d1_mtime = cur_time;
  for (i = 0; i < V1_NR_DZONES; i++)
	if (p->d1_zone[i] == 0) {
		p->d1_zone[i] = (zone1_t) z;
		put_block(b, (char *) inode);
		return;
	}
  put_block(b, (char *) inode);

  /* File has grown beyond a small file. */
  if (p->d1_zone[V1_NR_DZONES] == 0)
	p->d1_zone[V1_NR_DZONES] = (zone1_t) alloc_zone();
  indir = p->d1_zone[V1_NR_DZONES];
  put_block(b, (char *) inode);
  b = indir << zone_shift;
  get_block(b, (char *) blk);
  for (i = 0; i < V1_INDIRECTS; i++)
	if (blk[i] == 0) {
		blk[i] = (zone1_t) z;
		put_block(b, (char *) blk);
		return;
	}
  pexit("File has grown beyond single indirect");
}

void add_z_2(n, z, bytes, cur_time)
ino_t n;
zone_t z;
long bytes, cur_time;
{
  /* Add zone z to inode n. The file has grown by 'bytes' bytes. */

  int off, i;
  block_t b;
  zone_t indir;
  zone_t blk[V2_INDIRECTS];
  d2_inode *p;
  d2_inode inode[V2_INODES_PER_BLOCK];

  b = ((n - 1) / V2_INODES_PER_BLOCK) + inode_offset;
  off = (n - 1) % V2_INODES_PER_BLOCK;
  get_block(b, (char *) inode);
  p = &inode[off];
  p->d2_size += bytes;
  p->d2_mtime = cur_time;
  for (i = 0; i < V2_NR_DZONES; i++)
	if (p->d2_zone[i] == 0) {
		p->d2_zone[i] = z;
		put_block(b, (char *) inode);
		return;
	}
  put_block(b, (char *) inode);

  /* File has grown beyond a small file. */
  if (p->d2_zone[V2_NR_DZONES] == 0) p->d2_zone[V2_NR_DZONES] = alloc_zone();
  indir = p->d2_zone[V2_NR_DZONES];
  put_block(b, (char *) inode);
  b = indir << zone_shift;
  get_block(b, (char *) blk);
  for (i = 0; i < V2_INDIRECTS; i++)
	if (blk[i] == 0) {
		blk[i] = z;
		put_block(b, (char *) blk);
		return;
	}
  pexit("File has grown beyond single indirect");
}


void incr_link(n)
ino_t n;
{
  /* Increment the link count to inode n */
  int off;
  block_t b;

  b = ((n - 1) / inodes_per_block) + inode_offset;
  off = (n - 1) % inodes_per_block;
  if (fs_version == 1) {
	d1_inode inode1[V1_INODES_PER_BLOCK];

	get_block(b, (char *) inode1);
	inode1[off].d1_nlinks++;
	put_block(b, (char *) inode1);
  } else {
	d2_inode inode2[V2_INODES_PER_BLOCK];

	get_block(b, (char *) inode2);
	inode2[off].d2_nlinks++;
	put_block(b, (char *) inode2);
  }
}


void incr_size(n, count)
ino_t n;
long count;
{
  /* Increment the file-size in inode n */
  block_t b;
  int off;

  b = ((n - 1) / inodes_per_block) + inode_offset;
  off = (n - 1) % inodes_per_block;
  if (fs_version == 1) {
	d1_inode inode1[V1_INODES_PER_BLOCK];

	get_block(b, (char *) inode1);
	inode1[off].d1_size += count;
	put_block(b, (char *) inode1);
  } else {
	d2_inode inode2[V2_INODES_PER_BLOCK];

	get_block(b, (char *) inode2);
	inode2[off].d2_size += count;
	put_block(b, (char *) inode2);
  }
}


/*================================================================
 * 	 	     allocation assist group
 *===============================================================*/
PRIVATE ino_t alloc_inode(mode, usrid, grpid)
int mode, usrid, grpid;
{
  ino_t num;
  int off;
  block_t b;

  num = next_inode++;
  if (num > nrinodes) pexit("File system does not have enough inodes");
  b = ((num - 1) / inodes_per_block) + inode_offset;
  off = (num - 1) % inodes_per_block;
  if (fs_version == 1) {
	d1_inode inode1[V1_INODES_PER_BLOCK];

	get_block(b, (char *) inode1);
	inode1[off].d1_mode = mode;
	inode1[off].d1_uid = usrid;
	inode1[off].d1_gid = grpid;
	put_block(b, (char *) inode1);
  } else {
	d2_inode inode2[V2_INODES_PER_BLOCK];

	get_block(b, (char *) inode2);
	inode2[off].d2_mode = mode;
	inode2[off].d2_uid = usrid;
	inode2[off].d2_gid = grpid;
	put_block(b, (char *) inode2);
  }

  /* Set the bit in the bit map. */
  /* DEBUG FIXME.  This assumes the bit is in the first inode map block. */
  insert_bit((block_t) INODE_MAP, (int) num);
  return(num);
}


PRIVATE zone_t alloc_zone()
{
  /* Allocate a new zone */
  /* Works for zone > block */
  block_t b;
  int i;
  zone_t z;

  z = next_zone++;
  b = z << zone_shift;
  if ((b + zone_size) > nrblocks)
	pexit("File system not big enough for all the files");
  for (i = 0; i < zone_size; i++)
	put_block(b + i, zero);	/* give an empty zone */
  /* DEBUG FIXME.  This assumes the bit is in the first zone map block. */
  insert_bit(zone_map, (int) (z - zoff));	/* lint, NOT OK because
						 * z hasn't been broken
						 * up into block +
						 * offset yet. */
  return(z);
}


void insert_bit(block, bit)
block_t block;
int bit;
{
  /* Insert 'count' bits in the bitmap */
  int w, s;
  short buf[BLOCK_SIZE / sizeof(short)];

  if (block < 0) pexit("insert_bit called with negative argument");
  get_block(block, (char *) buf);
  w = bit / (8 * sizeof(short));
  s = bit % (8 * sizeof(short));
  buf[w] |= (1 << s);
  put_block(block, (char *) buf);
}


/*================================================================
 * 		proto-file processing assist group
 *===============================================================*/
int mode_con(p)
char *p;
{
  /* Convert string to mode */
  int o1, o2, o3, mode;
  char c1, c2, c3;

  c1 = *p++;
  c2 = *p++;
  c3 = *p++;
  o1 = *p++ - '0';
  o2 = *p++ - '0';
  o3 = *p++ - '0';
  mode = (o1 << 6) | (o2 << 3) | o3;
  if (c1 == 'd') mode += I_DIRECTORY;
  if (c1 == 'b') mode += I_BLOCK_SPECIAL;
  if (c1 == 'c') mode += I_CHAR_SPECIAL;
  if (c1 == '-') mode += I_REGULAR;
  if (c2 == 'u') mode += I_SET_UID_BIT;
  if (c3 == 'g') mode += I_SET_GID_BIT;
  return(mode);
}

void getline(line, parse)
char *parse[MAX_TOKENS];
char line[LINE_LEN];
{
  /* Read a line and break it up in tokens */
  int k;
  char c, *p;
  int d;

  for (k = 0; k < MAX_TOKENS; k++) parse[k] = 0;
  for (k = 0; k < LINE_LEN; k++) line[k] = 0;
  k = 0;
  parse[0] = 0;
  p = line;
  while (1) {
	if (++k > LINE_LEN) pexit("Line too long");
	d = fgetc(proto);
	if (d == EOF) pexit("Unexpected end-of-file");
	*p = d;
	if (*p == '\n') lct++;
	if (*p == ' ' || *p == '\t') *p = 0;
	if (*p == '\n') {
		*p++ = 0;
		*p = '\n';
		break;
	}
	p++;
  }

  k = 0;
  p = line;
  lastp = line;
  while (1) {
	c = *p++;
	if (c == '\n') return;
	if (c == 0) continue;
	parse[k++] = p - 1;
	do {
		c = *p++;
	} while (c != 0 && c != '\n');
  }
}


/*================================================================
 *			other stuff
 *===============================================================*/
void check_mtab(devname)
char *devname;			/* /dev/hd1 or whatever */
{
/* Check to see if the special file named in s is mounted. */

  int n;
  char special[PATH_MAX + 1], mounted_on[PATH_MAX + 1], version[10], rw_flag[10];

  if (load_mtab("mkfs") < 0) return;
  while (1) {
	n = get_mtab_entry(special, mounted_on, version, rw_flag);
	if (n < 0) return;
	if (strcmp(devname, special) == 0) {
		/* Can't mkfs on top of a mounted file system. */
		fprintf(stderr, "%s: %s is mounted on %s\n",
			progname, devname, mounted_on);
		exit(1);
	}
  }
}