isoread.c

操作系统源代码

/*
 * isoread.c
 *
 * isoread reads a file system in ISO9660 or HIGH SIERRA format from
 * a given device.
 *
 * Apr 5 1995     Michel R. Prevenier 
 */

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/times.h>
#include <unistd.h>

/*             
 *  definitions used by the ISO9660 and HIGH SIERRA file system
 */

#define ISO9660_ID	"CD001"
#define HIGH_SIERRA_ID	"CDROM"
#define BLOCK_SIZE	2048
#define BLOCK_SHIFT	11


/* Fields in a ISO9660 volume descriptor */
struct iso9660_descriptor
{
  char type[1];		
  char id[5];			
  char version[1];		
  char reserved1[1];		
  char system_id[32];		
  char volume_id[32];		
  char reserved2[8];		
  char volume_size[8];	
  char reserved3[32];		
  char volume_set_size[4];	
  char volume_seq_nr[4];
  char block_size[4];	
  char path_table_size[8];	
  char type_l_path_table[4];	
  char opt_type_l_path_table[4];	
  char type_m_path_table[4];	
  char opt_type_m_path_table[4];	
  char root_dir_entry[34];
  char vol_set_id[128];	
  char publ_id[128];
  char prep_id[128];	
  char appl_id[128];	
  char copyright_file_id[37];	
  char abstract_file_id[37];	
  char bibl_file_id[37];
  char creation_date[17];	
  char mod_date[17];	
  char exp_date[17];	
  char eff_date[17];	
  char file_struc_version[1];
  char reserved4[1];		
  char appl_data[512];	
  char reserved5[653];			
};


/* Fields in a High Sierra volume descriptor */
struct high_sierra_descriptor
{
  char reserved1[8];
  char type[1];	
  char id[5];		
  char version[1];	
  char reserved2[1];	
  char system_id[32];
  char volume_id[32];
  char reserved3[8];	
  char volume_size[8];	
  char reserved4[32];
  char vol_set_size[4];
  char volume_seq_nr[4];	
  char block_size[4];	
  char path_table_size[8];
  char type_l_path_table[4];
  char reserved5[28];		
  char root_dir_entry[34];
};


/* Fields in a directory entry */
struct dir_entry 
{
  char length[1];	
  char ext_attr_length[1];
  char first_block[8];
  char size[8];	
  char date[7];
  char flags[1];	
  char file_unit_size[1];
  char interleave[1];
  char volume_seq_nr[4];	
  char name_length[1];
  char name[1];
};


#define STDOUT		stdout
#define STDERR		stderr
#define NULL_DIR	(struct dir_entry *) 0
#define MAX_NAME_LENGTH	255
#define MAX_PATH_LENGTH	1024

#define NR_OF_CHARS	13 
#define NR_OF_BLANKS	2
#define NR_OF_COLS	(80 / (NR_OF_CHARS + NR_OF_BLANKS))

/* This macro always returns a lower case character */
#define LOWER_CASE(CHR) (CHR >= 'A' && CHR <= 'Z' ? CHR | 0x20 : CHR) 

/* Macro's for determining . , .. and normal directory entries */
#define IS_DOT(PTR) (PTR->name_length[0] == 1 && PTR->name[0] == 0 ? 1 : 0)
#define IS_DOT_DOT(PTR) (PTR->name_length[0] == 1 && PTR->name[0] == 1 ? 1 : 0)
#define IS_DIR(PTR) (PTR->flags[-High_Sierra] & 2 ? 1 : 0)


_PROTOTYPE (int main, (int argc, char **argv));
_PROTOTYPE (int iso_cmp, (char *name, struct dir_entry *dir_ptr, int dir_flag));
_PROTOTYPE (void list_dir, (struct dir_entry *dir_ptr));
_PROTOTYPE (void list_file, (struct dir_entry *dir_ptr));
_PROTOTYPE (struct dir_entry *look_up, (char *name));
_PROTOTYPE (void recurse_dir, (char *path, struct dir_entry *dir_ptr));
_PROTOTYPE (void read_device, (long offset, int nr_of_bytes, char *buffer));
_PROTOTYPE (int valid_fs, (void) );               
_PROTOTYPE (void usage, (void) );               
_PROTOTYPE (void print_date, (char *date));
_PROTOTYPE (void print_dir_date, (char *date));
_PROTOTYPE (void iso_info, (struct iso9660_descriptor *vol_desc));
_PROTOTYPE (void hs_info, (struct high_sierra_descriptor *vol_desc));
_PROTOTYPE (int iso_711, (char *c));
_PROTOTYPE (int iso_712, (char *c));
_PROTOTYPE (int iso_721, (char *c));
_PROTOTYPE (int iso_722, (char *c));
_PROTOTYPE (int iso_723, (char *c));
_PROTOTYPE (long iso_731, (char *c));
_PROTOTYPE (long iso_732, (char *c));
_PROTOTYPE (long iso_733, (char *c));


char Buffer[BLOCK_SIZE];	            /* buffer to hold read data */
int Device;				    /* global file descriptor */
struct iso9660_descriptor *Iso_Vol_Desc;    /* iso9660 volume descriptor */
struct high_sierra_descriptor *Hs_Vol_Desc; /* high sierra volume descriptor */
int High_Sierra = 0;                        /* 1 = high sierra format */
int Iso9660 = 0;                            /* 1 = iso9660 format */

/* This comes in handy when printing the date */
char months[] = "JanFebMarAprMayJunJulAugSepOctNovDec";

/* Flags displaying what to do  */
int Read_File = 0;      /* 1 = Read file */
int Read_Dir = 0;	/* 1 = Read directory entry */
int Read_Info = 0;      /* 1 = Read volume descriptor */
int Recurse = 0;        /* 1 = Recursively descend directories */
int Verbose = 0;        /* 1 = Print all info on directories */


int iso_cmp(name, dir_ptr, dir_flag)
char *name;
struct dir_entry *dir_ptr;
int dir_flag;
{
  int i;

  /* First match the filename */
  for (i = 0; (i < strlen(name) && i < iso_711(dir_ptr->name_length)); i++)
  {
    if (dir_ptr->name[i] == ';') break;
    if (name[i] != LOWER_CASE(dir_ptr->name[i])) return 1;
  }

  /* The filename is ok, now look at the file type */
  if (dir_flag && !IS_DIR(dir_ptr)) return 1;  /* File type not correct */

  return 0; 
}



void usage()
{
  if (Read_Dir)
   fprintf (STDERR, "Usage: isodir [-lr] inputfile [dir]\n");
  else if (Read_Info)
   fprintf (STDERR, "Usage: isoinfo inputfile\n");
  else
   fprintf (STDERR, "Usage: isoread inputfile file\n");
  exit(1);
}


int main(argc, argv)
int argc;
char **argv;
{
  struct dir_entry *entry;
  char path[MAX_PATH_LENGTH];
  char *input_file;
  char *basename;
  char *file_name;
  int i,j;

  /* Read arguments */
  basename = argv[0];
  while (*argv[0] != '\0') 
    if (*argv[0]++ == '/') basename = argv[0];

  if (strcmp(basename,"isodir") == 0) Read_Dir = 1;
  else if (strcmp(basename,"isoinfo") == 0) Read_Info = 1;
  else Read_File = 1;

  if ((argc > 5 && Read_Dir) || (argc > 2 && Read_Info) ||
     (argc > 3 && Read_File)) usage();

  i = 1;

  while (i < argc && argv[i][0] == '-')
  {
    char *opt = argv[i++] + 1;

    if (opt[0] == '-' && opt[1] == '\0') break;

    while (*opt != '\0')
    {
      if (!Read_Dir) usage();
      switch (*opt++)
      {
	case 'r':	Recurse = 1; break;  
	case 'l':	Verbose = 1; break;
	default:	usage();
      }
    }
  }

  if (i >= argc) usage();
  input_file = argv[i++];

  if (Read_File)
  {
    if (i >= argc) usage();
    file_name = argv[i++];
  }

  if (Read_Dir)
  {
    file_name = "/";
    if (i < argc)
    {
      file_name = argv[i++];
    }
  }

  if (i < argc) usage();
  
  if (Read_File || Read_Dir)
  {
    for (i=0; file_name[i] != '\0'; i++) 
      path[i] = LOWER_CASE(file_name[i]);
    path[i] = '\0';
  }
 
  /* Open file system (file or device) */
  if ((Device = open(input_file, O_RDONLY)) < 0) 
  {
    fprintf (STDERR, "cannot open %s\n", input_file);
    exit(-1);
  }

  
  if (!valid_fs())
  {
    fprintf (STDERR, "File system not in ISO9660 or HIGH SIERRA format \n");
    exit(-1);
  }

  
  if (Read_Info)
  {
    if (Iso9660) 
      iso_info(Iso_Vol_Desc);
    else 
      hs_info(Hs_Vol_Desc);
    exit(1);
  }

  /* Lookup file */
  if ((entry = look_up(path)) != NULL_DIR)
  {
    if (Read_Dir)
      if (Recurse) recurse_dir(path,entry);
      else list_dir(entry);
    else
      list_file(entry);
  }
  else
  {
    if (Read_Dir)
      fprintf (STDERR, "Directory");
    else
      fprintf (STDERR, "File");
    fprintf (STDERR, " %s not found\n", path);
    exit(-1);
  }
}


struct dir_entry *look_up(path)
char *path;
{
  /* Lookup a file name */

  struct dir_entry *dir_ptr;
  long block;
  int nr_of_blocks;
  int offset;
  char name[MAX_NAME_LENGTH + 1];
  int name_index = 0;
  int last_in_path = 0;
  int found;
  int i,j;

  /* Get the right dir entry structure */
  if (Iso9660)
    dir_ptr = (struct dir_entry *) Iso_Vol_Desc->root_dir_entry;  
  else
    dir_ptr = (struct dir_entry *) Hs_Vol_Desc->root_dir_entry;  

  /* If we look for the root we already have the right entry */
  if (path[0] == '/')
    if (strlen(path) == 1) return dir_ptr;
    else name_index = 1; /* first name in path */

  /* Keep searching for the path elements until all are found */
  while (!last_in_path)
  {
    /* Get next name in path */ 
    for (i = name_index; i < strlen(path); i++)
    {
      if (path[i] == '/') break;
      name[i - name_index] = path[i];
    }
    last_in_path = 
           (i == strlen(path) || (i == strlen(path) - 1 && path[i] == '/'));
    name[i-name_index] = '\0';
    name_index = i + 1;
   
    /* Get block of next directory */
    block = iso_733(dir_ptr->first_block) + iso_711(dir_ptr->ext_attr_length);
    nr_of_blocks = (int) (iso_733(dir_ptr->size) >> BLOCK_SHIFT);

    /* Search for file in dir entry */
    found = 0;
    for (j=0; j < nr_of_blocks && !found; j++) 
    {
      /* Read a directory block */
      read_device(block*BLOCK_SIZE, BLOCK_SIZE, Buffer);

      dir_ptr = (struct dir_entry *) Buffer;

      offset = 0;
      /* Compare with all entries in this block */
      while (iso_711(dir_ptr->length) > 0 && offset < BLOCK_SIZE)
      {
        if (iso_cmp(name, dir_ptr,
            (Read_Dir || (!Read_Dir && !last_in_path))) == 0) 
        {
          found = 1;
          break;
        }
        /* Next entry */
        offset += iso_711(dir_ptr->length);
        dir_ptr = (struct dir_entry *) (Buffer + offset);
      }
    }
    if (!found) return NULL_DIR;   /* path element not found */ 
  }
  return dir_ptr;
}
  

void recurse_dir(path, dir_ptr)
char *path;
struct dir_entry *dir_ptr;
{
  /* Recursively descend all directories starting with dir_ptr */

  char tmp_buffer[BLOCK_SIZE];