badblo~1.c

操作系统源代码

/* badblocks - collect bad blocks in a file	Author: Jacob Bunschoten */

/* Usage "badblocks block_special [Up_to_7_blocks]" */

/* This program is written to handle BADBLOCKS on a hard or floppy disk.
 * The program asks for block_numbers. These numbers can be obtained with
 * the program readall, written by A. Tanenbaum.  It then creates a
 * file on the disk containing up to 7 bad blocks.
 *
 * BUG:
 *
 *	When the zone_size > block_size it can happen that
 *	the zone is already allocated. This means some
 *	file is using this zone and may use all the blocks including
 *	the bad one. This can be cured by inspecting the zone_bitmap
 *	(is already done) and change the file if this zone is used.
 *	This means that another zone must be allocated and
 *	the inode wich claims this zone must be found and changed.
 *
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <minix/config.h>
#include <minix/type.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

#include "../../fs/const.h"	/* must be included before stdio.h */
#undef printf			/* so its define of printf can be undone */
#include "../../fs/type.h"

#include <string.h>
#include <stdio.h>

_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(void rw_super, (int flag));
_PROTOTYPE(void get_super, (void));
_PROTOTYPE(void put_super, (void));
_PROTOTYPE(void rw_inode, (struct stat * stat_ptr, int rw_mode));
_PROTOTYPE(void get_inode, (struct stat * stat_ptr));
_PROTOTYPE(void put_inode, (struct stat * stat_ptr));
_PROTOTYPE(long rd_cmdline, (int argc, char *argv[]));
_PROTOTYPE(void modify, (int nr_blocks));
_PROTOTYPE(void save_blk, (block_t blk_num));
_PROTOTYPE(void reset_blks, (void));
_PROTOTYPE(void show_blks, (void));
_PROTOTYPE(int blk_is_used, (block_t blk_num));
_PROTOTYPE(int blk_ok, (block_t num));
_PROTOTYPE(void set_bit, (zone_t num));
_PROTOTYPE(long rd_num, (void));
_PROTOTYPE(int ok, (char *str));
_PROTOTYPE(void done, (int nr));

/* 		Super block table.
 *
 * 	The disk layout is:
 *
 *      Item        # block
 *    boot block      1
 *    super block     1
 *    inode map     s_imap_blocks
 *    zone map      s_zmap_blocks
 *    inodes        (s_ninodes + 1 + inodes_per_block - 1)/inodes_per_block
 *    unused
 *    data zones    (s_nzones - s_firstdatazone) << s_log_zone_size
 *
 */

#define OK	0
#define NOT_OK	1
#define QUIT	2

#define READ 	0
#define WRITE	1

#define HARMLESS	0
#define DIR_CREATED	1
#define DEV_MOUNTED	2
#define FILE_EXISTS	3
#define SUCCESS		4

#define BYTE         0377
#define BLOCK_SIZE   1024
#define SIZE_OF_INT   (sizeof (int) )

/* Define V_NR_DZONES as the larger of V1_NR_DZONES and V2_NR_DZONES. */
#if (V1_NR_DZONES > V2_NR_DZONES)
#define V_NR_DZONES V1_NR_DZONES
#define V_SMALLER   V2_NR_DZONES
#else
#define V_NR_DZONES V2_NR_DZONES
#define V_SMALLER   V1_NR_DZONES
#endif

struct super_block {
  ino_t s_ninodes;		/* # usable inodes on the minor device */
  zone1_t s_nzones;		/* total device size, including bit maps etc */
  short s_imap_blocks;		/* # of blocks used by inode bit map */
  short s_zmap_blocks;		/* # of blocks used by zone bit map */
  zone1_t s_firstdatazone;	/* number of first data zone */
  short s_log_zone_size;	/* log2 of blocks/zone */
  off_t s_max_size;		/* maximum file size on this device */
  short s_magic;		/* magic number to recognize super-blocks */
  short s_pad;			/* try to avoid compiler-dependent padding */
  zone_t s_zones;		/* number of zones (replaces s_nzones in V2) */
} super_block;

 /* ====== globals ======= */

char *dev_name;
char f_name[] = ".Bad_XXXXXX";
char file_name[50];
char dir_name[] = "/tmpXXXXXX";

block_t block[V_NR_DZONES + 1];	/* last block contains zero */
int interactive;		/* 1 if interactive (argc == 2) */
int position = 2;		/* next block # is argv[position] */

FILE *f;
int fd;
int eofseen;			/* set if '\n' seen */
struct stat stat_buf;
struct super_block *sp;
int inodes_per_block;
size_t inode_size;
int v1fs;			/* TRUE for V1 file system, FALSE for V2 */

d1_inode d1inode;		/* declare a V1 disk inode */
d1_inode *ip1;
d2_inode d2inode;		/* declare a V2 disk inode */
d2_inode *ip2;


 /* ====== super block routines ======= */

void rw_super(flag)
int flag;
{				/* read or write a superblock */
  int rwd;

  lseek(fd, 0L, SEEK_SET);	/* rewind */
  lseek(fd, (long) BLOCK_SIZE, SEEK_SET);	/* seek */

  if (flag == READ)
	rwd = read(fd, (char *) sp, SUPER_SIZE);
  else
	rwd = write(fd, (char *) sp, SUPER_SIZE);
  if (rwd != SUPER_SIZE) {	/* ok ? */
	printf("Bad %s in get_super() (should be %u is %d)\n",
	       flag == READ ? "read" : "write",
	       (unsigned) SUPER_SIZE, rwd);
	done(DIR_CREATED);
  }
}

void get_super()
 /* Get super_block. global pointer sp is used */
{
  rw_super(READ);

  if (sp->s_magic == SUPER_MAGIC) {
	/* This is a V1 file system. */
	v1fs = 1;		/* file system is not V2 */
  } else if (sp->s_magic == SUPER_V2) {
	/* This is a V2 file system. */
	v1fs = 0;		/* this is a V2 file system */
  } else {
	/* Neither V1 nor V2. */
	printf("Bad magic number in super_block (0x%x)\n",
	       (unsigned) sp->s_magic);
	done(DIR_CREATED);
  }
}


void put_super()
{
  rw_super(WRITE);
}

 /* ========== inode routines =========== */

void rw_inode(stat_ptr, rw_mode)
struct stat *stat_ptr;
int rw_mode;
{
  int rwd;
  ino_t i_num;
  block_t blk, offset;


  i_num = stat_ptr->st_ino;

  blk = (block_t) (2 + sp->s_imap_blocks + sp->s_zmap_blocks);
  blk += (block_t) ((i_num - 1) / inodes_per_block);
  blk *= (block_t) (BLOCK_SIZE);/* this block */

  offset = (block_t) ((i_num - 1) % inodes_per_block);
  offset *= (block_t) (inode_size);	/* and this offset */

  lseek(fd, (off_t) 0, SEEK_SET);	/* rewind */
  lseek(fd, (off_t) (blk + offset), SEEK_SET);	/* seek */

  /* Pointer is at the inode */
  if (v1fs) {
	/* This is a V1 file system. */
	if (rw_mode == READ) {	/* read it */
		rwd = read(fd, (char *) ip1, inode_size);
	} else {		/* write it */
		rwd = write(fd, (char *) ip1, inode_size);
	}
  } else {
	/* This is a V2 file system. */
	if (rw_mode == READ) {	/* read it */
		rwd = read(fd, (char *) ip2, inode_size);
	} else {		/* write it */
		rwd = write(fd, (char *) ip2, inode_size);
	}
  }

  if (rwd != inode_size) {	/* ok ? */
	printf("Bad %s in get_inode()\n", (rw_mode == READ) ? "read" :
	       "write");
	done(DIR_CREATED);
  }
}

void get_inode(stat_ptr)
struct stat *stat_ptr;
{

  int cnt;

  rw_inode(stat_ptr, READ);

  if (v1fs) {
	for (cnt = 0; cnt < V1_NR_TZONES; cnt++)
		ip1->d1_zone[cnt] = 0;	/* Just to be safe */
  } else {
	for (cnt = 0; cnt < V2_NR_TZONES; cnt++)
		ip2->d2_zone[cnt] = 0;	/* Just to be safe */
  }
}

void put_inode(stat_ptr)
struct stat *stat_ptr;
{
  rw_inode(stat_ptr, WRITE);
}


 /* ==============  main program ================= */
int main(argc, argv)
int argc;
char *argv[];
{
  int cnt, finished;
  block_t blk_nr;
  struct stat dev_stat;
  FILE *fp;

  sp = &super_block;
  ip1 = &d1inode;
  ip2 = &d2inode;

  if (argc < 2 || argc > 9) {
	fprintf(stderr, "Usage: %s block_special [up_to_7_blocks]\n", argv[0]);
	done(HARMLESS);
  }
  interactive = (argc == 2 ? 1 : 0);

  /* Do some test. */
  if (geteuid()) {
	printf("Sorry, not in superuser mode \n");
	printf("Set_uid bit must be on or you must become super_user\n");
	done(HARMLESS);
  }
  dev_name = argv[1];
  mktemp(dir_name);
  if (mkdir(dir_name, 0777) == -1) {
	fprintf(stderr, "%s is already used in system\n", dir_name);
	done(HARMLESS);
  }

  /* Mount device. This call may fail. */
  mount(dev_name, dir_name, 0);
  /* Succes. dev was mounted, try to umount */

  /* Umount device. Playing with the file system while other processes
   * have access to this device is asking for trouble */
  if (umount(dev_name) == -1) {
	printf("Could not umount device %s.\n", dev_name);
	done(HARMLESS);
  }
  mktemp(f_name);
  /* Create "/tmpXXXXpid/.BadXXpid" */
  strcat(file_name, dir_name);
  strcat(file_name, "/");
  strcat(file_name, f_name);

  if (mount(dev_name, dir_name, 0) == -1) {	/* this call should work */
	fprintf(stderr, "Could not mount device anymore\n");
	done(HARMLESS);
  }
  if (stat(file_name, &stat_buf) != -1) {
	printf("File %s already exists\n", file_name);
	done(DEV_MOUNTED);
  }
  if ((fp = fopen(file_name, "w")) == NULL) {
	printf("Cannot create file %s\n", file_name);
	done(DEV_MOUNTED);
  }
  chmod(file_name, 0);		/* "useless" file */
  if (stat(file_name, &stat_buf) == -1) {
	printf("What? Second call from stat failed\n");
	done(FILE_EXISTS);
  }

  /* Stat buf must be safed. We can now calculate the inode on disk */
  fclose(fp);

  /* ===== the badblock file is created ===== */