int tar()

in contrib/libz/contrib/untgz/untgz.c [386:576]

• 155 lines of code
• 40 McCabe index (conditional complexity)

int tar (gzFile in,int action,int arg,int argc,char **argv)
{
  union  tar_buffer buffer;
  int    len;
  int    err;
  int    getheader = 1;
  int    remaining = 0;
  FILE   *outfile = NULL;
  char   fname[BLOCKSIZE];
  int    tarmode;
  time_t tartime;
  struct attr_item *attributes = NULL;

  if (action == TGZ_LIST)
    printf("    date      time     size                       file\n"
           " ---------- -------- --------- -------------------------------------\n");
  while (1)
    {
      len = gzread(in, &buffer, BLOCKSIZE);
      if (len < 0)
        error(gzerror(in, &err));
      /*
       * Always expect complete blocks to process
       * the tar information.
       */
      if (len != BLOCKSIZE)
        {
          action = TGZ_INVALID; /* force error exit */
          remaining = 0;        /* force I/O cleanup */
        }

      /*
       * If we have to get a tar header
       */
      if (getheader >= 1)
        {
          /*
           * if we met the end of the tar
           * or the end-of-tar block,
           * we are done
           */
          if (len == 0 || buffer.header.name[0] == 0)
            break;

          tarmode = getoct(buffer.header.mode,8);
          tartime = (time_t)getoct(buffer.header.mtime,12);
          if (tarmode == -1 || tartime == (time_t)-1)
            {
              buffer.header.name[0] = 0;
              action = TGZ_INVALID;
            }

          if (getheader == 1)
            {
              strncpy(fname,buffer.header.name,SHORTNAMESIZE);
              if (fname[SHORTNAMESIZE-1] != 0)
                  fname[SHORTNAMESIZE] = 0;
            }
          else
            {
              /*
               * The file name is longer than SHORTNAMESIZE
               */
              if (strncmp(fname,buffer.header.name,SHORTNAMESIZE-1) != 0)
                  error("bad long name");
              getheader = 1;
            }

          /*
           * Act according to the type flag
           */
          switch (buffer.header.typeflag)
            {
            case DIRTYPE:
              if (action == TGZ_LIST)
                printf(" %s     <dir> %s\n",strtime(&tartime),fname);
              if (action == TGZ_EXTRACT)
                {
                  makedir(fname);
                  push_attr(&attributes,fname,tarmode,tartime);
                }
              break;
            case REGTYPE:
            case AREGTYPE:
              remaining = getoct(buffer.header.size,12);
              if (remaining == -1)
                {
                  action = TGZ_INVALID;
                  break;
                }
              if (action == TGZ_LIST)
                printf(" %s %9d %s\n",strtime(&tartime),remaining,fname);
              else if (action == TGZ_EXTRACT)
                {
                  if (matchname(arg,argc,argv,fname))
                    {
                      outfile = fopen(fname,"wb");
                      if (outfile == NULL) {
                        /* try creating directory */
                        char *p = strrchr(fname, '/');
                        if (p != NULL) {
                          *p = '\0';
                          makedir(fname);
                          *p = '/';
                          outfile = fopen(fname,"wb");
                        }
                      }
                      if (outfile != NULL)
                        printf("Extracting %s\n",fname);
                      else
                        fprintf(stderr, "%s: Couldn't create %s",prog,fname);
                    }
                  else
                    outfile = NULL;
                }
              getheader = 0;
              break;
            case GNUTYPE_LONGLINK:
            case GNUTYPE_LONGNAME:
              remaining = getoct(buffer.header.size,12);
              if (remaining < 0 || remaining >= BLOCKSIZE)
                {
                  action = TGZ_INVALID;
                  break;
                }
              len = gzread(in, fname, BLOCKSIZE);
              if (len < 0)
                error(gzerror(in, &err));
              if (fname[BLOCKSIZE-1] != 0 || (int)strlen(fname) > remaining)
                {
                  action = TGZ_INVALID;
                  break;
                }
              getheader = 2;
              break;
            default:
              if (action == TGZ_LIST)
                printf(" %s     <---> %s\n",strtime(&tartime),fname);
              break;
            }
        }
      else
        {
          unsigned int bytes = (remaining > BLOCKSIZE) ? BLOCKSIZE : remaining;

          if (outfile != NULL)
            {
              if (fwrite(&buffer,sizeof(char),bytes,outfile) != bytes)
                {
                  fprintf(stderr,
                    "%s: Error writing %s -- skipping\n",prog,fname);
                  fclose(outfile);
                  outfile = NULL;
                  remove(fname);
                }
            }
          remaining -= bytes;
        }

      if (remaining == 0)
        {
          getheader = 1;
          if (outfile != NULL)
            {
              fclose(outfile);
              outfile = NULL;
              if (action != TGZ_INVALID)
                push_attr(&attributes,fname,tarmode,tartime);
            }
        }

      /*
       * Abandon if errors are found
       */
      if (action == TGZ_INVALID)
        {
          error("broken archive");
          break;
        }
    }

  /*
   * Restore file modes and time stamps
   */
  restore_attr(&attributes);

  if (gzclose(in) != Z_OK)
    error("failed gzclose");

  return 0;
}