funzip.c

完整的解压zip文件的源码。包含密码功能

#if CRYPT
  char *s = " [-password]";
  char *p;                      /* password */
#else /* !CRYPT */
  char *s = "";
#endif /* ?CRYPT */
  CONSTRUCTGLOBALS();

  /* skip executable name */
  argc--;
  argv++;

#if CRYPT
  /* get the command line password, if any */
  p = (char *)NULL;
  if (argc && **argv == '-')
  {
    argc--;
    p = 1 + *argv++;
  }
#endif /* CRYPT */

#ifdef MALLOC_WORK
  G.area.Slide = (uch *)calloc(8193, sizeof(short)+sizeof(char)+sizeof(char));
#endif

  /* if no file argument and stdin not redirected, give the user help */
  if (argc == 0 && isatty(0))
  {
    Info(slide, 1, ((char *)slide, "fUnZip (filter UnZip), version %s\n",
      VERSION));
    Info(slide, 1, ((char *)slide, "usage: ... | funzip%s | ...\n", s));
    Info(slide, 1, ((char *)slide, "       ... | funzip%s > outfile\n", s));
    Info(slide, 1, ((char *)slide, "       funzip%s infile.zip > outfile\n",s));
    Info(slide, 1, ((char *)slide, "       funzip%s infile.gz > outfile\n", s));
    Info(slide, 1, ((char *)slide, "Extracts to stdout the gzip file or first\
 zip entry of stdin or the given file.\n"));
    DESTROYGLOBALS()
    EXIT(3);
  }

  /* prepare to be a binary filter */
  if (argc)
  {
    if ((G.in = fopen(*argv, FOPR)) == (FILE *)NULL)
      err(2, "cannot find input file");
  }
  else
  {
#ifdef DOS_FLX_H68_OS2_W32
#if (defined(__HIGHC__) && !defined(FLEXOS))
    setmode(stdin, _BINARY);
#else
    setmode(0, O_BINARY);  /* some buggy C libraries require BOTH setmode() */
#endif                     /*  call AND the fdopen() in binary mode :-( */
#endif /* DOS_FLX_H68_OS2_W32 */

#ifdef RISCOS
    G.in = stdin;
#else
    if ((G.in = fdopen(0, FOPR)) == (FILE *)NULL)
      err(2, "cannot find stdin");
#endif
  }

#ifdef DOS_FLX_H68_OS2_W32
#if (defined(__HIGHC__) && !defined(FLEXOS))
  setmode(stdout, _BINARY);
#else
  setmode(1, O_BINARY);
#endif
#endif /* DOS_FLX_H68_OS2_W32 */

#ifdef RISCOS
  out = stdout;
#else
  if ((out = fdopen(1, FOPW)) == (FILE *)NULL)
    err(2, "cannot write to stdout");
#endif

  /* read local header, check validity, and skip name and extra fields */
  n = getc(G.in);  n |= getc(G.in) << 8;
  if (n == ZIPMAG)
  {
    if (fread((char *)h, 1, LOCHDR, G.in) != LOCHDR || SH(h) != LOCREM)
      err(3, "invalid zipfile");
    if (SH(h + LOCHOW) != STORED && SH(h + LOCHOW) != DEFLATED)
      err(3, "first entry not deflated or stored--cannot unpack");
    for (n = SH(h + LOCFIL); n--; ) g = getc(G.in);
    for (n = SH(h + LOCEXT); n--; ) g = getc(G.in);
    g = 0;
    encrypted = h[LOCFLG] & CRPFLG;
  }
  else if (n == GZPMAG)
  {
    if (fread((char *)h, 1, GZPHDR, G.in) != GZPHDR)
      err(3, "invalid gzip file");
    if (h[GZPHOW] != DEFLATED)
      err(3, "gzip file not deflated");
    if (h[GZPFLG] & GZPMUL)
      err(3, "cannot handle multi-part gzip files");
    if (h[GZPFLG] & GZPISX)
    {
      n = getc(G.in);  n |= getc(G.in) << 8;
      while (n--) g = getc(G.in);
    }
    if (h[GZPFLG] & GZPISF)
      while ((g = getc(G.in)) != 0 && g != EOF) ;
    if (h[GZPFLG] & GZPISC)
      while ((g = getc(G.in)) != 0 && g != EOF) ;
    g = 1;
    encrypted = h[GZPFLG] & GZPISE;
  }
  else
    err(3, "input not a zip or gzip file");

  /* if entry encrypted, decrypt and validate encryption header */
  if (encrypted)
#if CRYPT
    {
      ush i, e;

      if (p == (char *)NULL) {
        if ((p = (char *)malloc(IZ_PWLEN+1)) == (char *)NULL)
          err(1, "out of memory");
        else if ((p = getp("Enter password: ", p, IZ_PWLEN+1)) == (char *)NULL)
          err(1, "no tty to prompt for password");
      }
#if (defined(USE_ZLIB) && !defined(USE_OWN_CRCTAB))
      /* initialize crc_32_tab pointer for decryption */
      CRC_32_TAB = (ZCONST ulg Far *)get_crc_table();
#endif
      init_keys(p);
      for (i = 0; i < RAND_HEAD_LEN; i++)
        e = NEXTBYTE;
      if (e != (ush)(h[LOCFLG] & EXTFLG ? h[LOCTIM + 1] : h[LOCCRC + 3]))
        err(3, "incorrect password for first entry");
    }
#else /* !CRYPT */
    err(3, "cannot decrypt entry (need to recompile with full crypt.c)");
#endif /* ?CRYPT */

  /* prepare output buffer and crc */
  G.outptr = slide;
  G.outcnt = 0L;
  outsiz = 0L;
  G.crc32val = CRCVAL_INITIAL;

  /* decompress */
  if (g || h[LOCHOW])
  {                             /* deflated entry */
    int r;

#ifdef USE_ZLIB
    /* need to allocate and prepare input buffer */
    if ((G.inbuf = (uch *)malloc(INBUFSIZ)) == (uch *)NULL)
       err(1, "out of memory");
#endif /* USE_ZLIB */
    if ((r = UZinflate(__G)) != 0) {
      if (r == 3)
        err(1, "out of memory");
      else
        err(4, "invalid compressed data--format violated");
    }
    inflate_free(__G);
  }
  else
  {                             /* stored entry */
    register ulg n;

    n = LG(h + LOCLEN);
#if CRYPT
    if (n != LG(h + LOCSIZ) - (encrypted ? RAND_HEAD_LEN : 0)) {
#else
    if (n != LG(h + LOCSIZ)) {
#endif
      Info(slide, 1, ((char *)slide, "len %ld, siz %ld\n", n, LG(h + LOCSIZ)));
      err(4, "invalid compressed data--length mismatch");
    }
    while (n--) {
      ush c = getc(G.in);
#if CRYPT
      if (encrypted)
        zdecode(c);
#endif
      *G.outptr++ = (uch)c;
      if (++G.outcnt == WSIZE)    /* do FlushOutput() */
      {
        G.crc32val = crc32(G.crc32val, slide, (extent)G.outcnt);
        if (fwrite((char *)slide, 1,(extent)G.outcnt,out) != (extent)G.outcnt
            && !PIPE_ERROR)
          err(9, "out of space on stdout");
        outsiz += G.outcnt;
        G.outptr = slide;
        G.outcnt = 0L;
      }
    }
  }
  if (G.outcnt)   /* flush one last time; no need to reset G.outptr/outcnt */
  {
    G.crc32val = crc32(G.crc32val, slide, (extent)G.outcnt);
    if (fwrite((char *)slide, 1,(extent)G.outcnt,out) != (extent)G.outcnt
        && !PIPE_ERROR)
      err(9, "out of space on stdout");
    outsiz += G.outcnt;
  }
  fflush(out);

  /* if extended header, get it */
  if (g)
  {
    if (fread((char *)h + LOCCRC, 1, 8, G.in) != 8)
      err(3, "gzip file ended prematurely");
  }
  else
    if ((h[LOCFLG] & EXTFLG) &&
        fread((char *)h + LOCCRC - 4, 1, EXTHDR, G.in) != EXTHDR)
      err(3, "zipfile ended prematurely");

  /* validate decompression */
  if (LG(h + LOCCRC) != G.crc32val)
    err(4, "invalid compressed data--crc error");
  if (LG((g ? (h + LOCSIZ) : (h + LOCLEN))) != outsiz)
    err(4, "invalid compressed data--length error");

  /* check if there are more entries */
  if (!g && fread((char *)h, 1, 4, G.in) == 4 && LG(h) == LOCSIG)
    Info(slide, 1, ((char *)slide,
      "funzip warning: zipfile has more than one entry--rest ignored\n"));

  DESTROYGLOBALS()
  RETURN (0);
}