update.

[chise/xemacs-chise.git.1] / nt / minitar.c

/* Minitar:  extract .tar.gz files on Win32 platforms. 
   Uses zlib for decompression.
   
   This is very simple-minded, it ignores checksums, and any type of file 
   that is not a plain file or a directory.  Nonetheless it is useful.

   Author: Charles G. Waldman (cgw@pgt.com),  Aug 4 1998

   This file is placed in the public domain; you can
   do whatever you like with it.  There is NO WARRANTY. 
   If it breaks, you get to keep both pieces */


#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <io.h>
#ifdef WIN32_NATIVE
# include <direct.h>    /* For mkdir */
#endif

#include <zlib.h>

static void
Usage (char *name)
{
  fprintf (stderr, "Usage: %s file.tar.gz [base-dir]\n", name);
  fprintf (stderr, "\tExtracts the contents compressed tar file to base-dir\n");
  exit (-1);
}


#define BLOCKSIZE 512
#define MAXNAMELEN 1024

static int
octal (char *str)
{
  int ret = -1;
  sscanf (str, "%o", &ret);
  return ret;
}

/* this is like mkdir -p, except if there is no trailing slash,
   the final component is assumed to be a file, rather than a
   path component, so it is not created as a directory */

static int
makepath (char *path)
{
  char tmp[MAXNAMELEN];
  char *cp;

  for (cp=path; cp; cp = (char*)strchr (cp+1, '/'))
    {
      if (!*cp)
        break;
      if (*cp != '/')
        continue;
      strncpy (tmp, path, cp-path);
      tmp[cp-path] = '\0';
      if (strlen (tmp) == 0)
        continue;
#ifdef WIN32_NATIVE
      if (mkdir (tmp))
#else
        if (mkdir (tmp, 0777))
#endif
          {
            if (errno == EEXIST)
              continue;
            else
              return -1;
          }
    }
  return 0;
}



int
main (int argc, char **argv)
{
  char fullname[MAXNAMELEN];
  char *basedir = ".";
  char *tarfile;
  int size;
  char osize[13];
  char name[101];
  char magic[7];
  char type;
  
  gzFile *infile = (gzFile*)0;
  FILE *outfile = (FILE*)0;

  char block[BLOCKSIZE];
  int nbytes, nread, nwritten;

  int in_block = 0;
  int directory = 0;

  if (argc < 2 || argc > 3)
    Usage (argv[0]);

  tarfile = argv[1];
  if (argc==3)
    basedir = argv[2];

  if (! (infile = gzopen (tarfile, "rb")))
    {
      fprintf (stderr, "Cannot open %s\n", tarfile);
      exit (-2);
    }
  
  while (1)
    {
      nread = gzread (infile, block, 512);

      if (!in_block && nread == 0)
        break;

      if (nread != BLOCKSIZE)
        {
          fprintf (stderr, "Error: incomplete block read. Exiting.\n");
          exit (-2);
        }

      if (!in_block)
        {
          if (block[0]=='\0')  /* We're done */
            break;

          strncpy (magic, block+257, 6);
          magic[6] = '\0';
          if (strcmp (magic, "ustar "))
            {
              fprintf (stderr,
                       "Error: incorrect magic number in tar header. Exiting\n");
              exit (-2);
            }

          strncpy (name, block, 100);
          name[100] = '\0';
          sprintf (fullname, "%s/%s", basedir, name);
          printf ("%s\n", fullname);
          type = block[156];
      
          switch (type)
            {
            case '0':
            case '\0':
              directory = 0;
              break;
            case '5':
              directory = 1;
              break;
            default:
              fprintf (stderr, "Error: unknown type flag %c. Exiting.\n", type);
              exit (-2);
              break;
            }
      
          if (directory)
            {
              in_block = 0;
        
              /* makepath will ignore the final path component, so make sure 
                 dirnames have a trailing slash */

              if (fullname[strlen (fullname)-1] != '/')
                strcat (fullname, "/");
              if (makepath (fullname))
                {
                  fprintf (stderr, "Error: cannot create directory %s. Exiting.\n",
                           fullname);
                  exit (-2);
                }
              continue;
            }
          else
            { /*file */
              in_block = 1;
              if (outfile)
                {
                  if (fclose (outfile))
                    {
                      fprintf (stderr, "Error: cannot close file %s. Exiting.\n",
                               fullname);
                      exit (-2);
                    }
                  outfile = (FILE*)0;
                }

              if (!(outfile = fopen (fullname, "wb")))
                {
                  /*try creating the directory, maybe it's not there */
                  if (makepath (fullname))
                    {
                      fprintf (stderr, "Error: cannot create file %s. Exiting.\n",
                               fullname);
                      exit (-2);
                    }
                  /* now try again to open the file */
                  if (!(outfile = fopen (fullname, "wb")))
                    {
                      fprintf (stderr, "Error: cannot create file %s. Exiting.\n",
                               fullname);
                      exit (-2);
                    }
                }

              strncpy (osize, block+124, 12);
              osize[12] = '\0';
              size = octal (osize);
              if (size<0)
                {
                  fprintf (stderr, "Error: invalid size in tar header. Exiting.\n");
                  exit (-2);
                }
              if (size==0)      /* file of size 0 is done */
                in_block = 0;
            }
        }
      else
        { /* write or continue writing file contents */
          nbytes = size>512? 512:size;
      
          nwritten = fwrite (block, 1, nbytes, outfile);
          if (nwritten != nbytes)
            {
              fprintf (stderr, "Error: only wrote %d bytes to file %s. Exiting.\n",
                       nwritten, fullname);
              exit (-2);
            }
          size -= nbytes;
          if (size==0)
            in_block = 0;
        }
    }
  return 0;
}