unzip.c

手机嵌入式Linux下可用的busybox源码

			/* read in table lengths */
			while (k_dynamic < 5) {
				input_char = fgetc(in_file);
				if (input_char == EOF) return 1;
				b_dynamic |= ((unsigned long)input_char) << k_dynamic;
				k_dynamic += 8;
			}
			nl = 257 + ((unsigned) b_dynamic & 0x1f);	/* number of literal/length codes */
			b_dynamic >>= 5;
			k_dynamic -= 5;
			while (k_dynamic < 5) {
				input_char = fgetc(in_file);
				if (input_char == EOF) return 1;
				b_dynamic |= ((unsigned long)input_char) << k_dynamic;
				k_dynamic += 8;
			}
			nd = 1 + ((unsigned) b_dynamic & 0x1f);	/* number of distance codes */
			b_dynamic >>= 5;
			k_dynamic -= 5;
			while (k_dynamic < 4) {
				input_char = fgetc(in_file);
				if (input_char == EOF) return 1;
				b_dynamic |= ((unsigned long)input_char) << k_dynamic;
				k_dynamic += 8;
			}
			nb = 4 + ((unsigned) b_dynamic & 0xf);	/* number of bit length codes */
			b_dynamic >>= 4;
			k_dynamic -= 4;
			if (nl > 286 || nd > 30) {
				return 1;	/* bad lengths */
			}

			/* read in bit-length-code lengths */
			for (j = 0; j < nb; j++) {
				while (k_dynamic < 3) {
					input_char = fgetc(in_file);
					if (input_char == EOF) return 1;
					b_dynamic |= ((unsigned long)input_char) << k_dynamic;
					k_dynamic += 8;
				}
				ll[border[j]] = (unsigned) b_dynamic & 7;
				b_dynamic >>= 3;
				k_dynamic -= 3;
			}
			for (; j < 19; j++) {
				ll[border[j]] = 0;
			}

			/* build decoding table for trees--single level, 7 bit lookup */
			bl = 7;
			if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
				if (i == 1) {
					huft_free(tl);
				}
				return i;			/* incomplete code set */
			}

			/* read in literal and distance code lengths */
			n = nl + nd;
			m = mask_bits[bl];
			i = l = 0;
			while ((unsigned) i < n) {
				while (k_dynamic < (unsigned) bl) {
					input_char = fgetc(in_file);
					if (input_char == EOF) return 1;
					b_dynamic |= ((unsigned long)input_char) << k_dynamic;
					k_dynamic += 8;
				}
				j = (td = tl + ((unsigned) b_dynamic & m))->b;
				b_dynamic >>= j;
				k_dynamic -= j;
				j = td->v.n;
				if (j < 16) {			/* length of code in bits (0..15) */
					ll[i++] = l = j;	/* save last length in l */
				}
				else if (j == 16) {		/* repeat last length 3 to 6 times */
					while (k_dynamic < 2) {
						input_char = fgetc(in_file);
						if (input_char == EOF) return 1;
						b_dynamic |= ((unsigned long)input_char) << k_dynamic;
						k_dynamic += 8;
					}
					j = 3 + ((unsigned) b_dynamic & 3);
					b_dynamic >>= 2;
					k_dynamic -= 2;
					if ((unsigned) i + j > n) {
						return 1;
					}
					while (j--) {
						ll[i++] = l;
					}
				} else if (j == 17) {	/* 3 to 10 zero length codes */
					while (k_dynamic < 3) {
						input_char = fgetc(in_file);
						if (input_char == EOF) return 1;
						b_dynamic |= ((unsigned long)input_char) << k_dynamic;
						k_dynamic += 8;
					}
					j = 3 + ((unsigned) b_dynamic & 7);
					b_dynamic >>= 3;
					k_dynamic -= 3;
					if ((unsigned) i + j > n) {
						return 1;
					}
					while (j--) {
						ll[i++] = 0;
					}
					l = 0;
				} else {		/* j == 18: 11 to 138 zero length codes */
					while (k_dynamic < 7) {
						input_char = fgetc(in_file);
						if (input_char == EOF) return 1;
						b_dynamic |= ((unsigned long)input_char) << k_dynamic;
						k_dynamic += 8;
					}
					j = 11 + ((unsigned) b_dynamic & 0x7f);
					b_dynamic >>= 7;
					k_dynamic -= 7;
					if ((unsigned) i + j > n) {
						return 1;
					}
					while (j--) {
						ll[i++] = 0;
					}
					l = 0;
				}
			}

			/* free decoding table for trees */
			huft_free(tl);

			/* restore the global bit buffer */
			bb = b_dynamic;
			bk = k_dynamic;

			/* build the decoding tables for literal/length and distance codes */
			bl = lbits;
			if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
				if (i == 1) {
					error_msg("Incomplete literal tree");
					huft_free(tl);
				}
				return i;			/* incomplete code set */
			}
			bd = dbits;
			if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
				if (i == 1) {
					error_msg("incomplete distance tree");
					huft_free(td);
				}
				huft_free(tl);
				return i;			/* incomplete code set */
			}

			/* decompress until an end-of-block code */
			if (inflate_codes(tl, td, bl, bd))
				return 1;

			/* free the decoding tables, return */
			huft_free(tl);
			huft_free(td);
			return 0;
		}
	default:
		/* bad block type */
		return 2;
	}
}

/*
 * decompress an inflated entry
 *
 * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
 */
static int inflate()
{
	int e;				/* last block flag */
	int r;				/* result code */
	unsigned h = 0;		/* maximum struct huft's malloc'ed */

	/* initialize window, bit buffer */
	outcnt = 0;
	bk = 0;
	bb = 0;

	/* decompress until the last block */
	do {
		hufts = 0;
		if ((r = inflate_block(&e)) != 0) {
			return r;
		}
		if (hufts > h) {
			h = hufts;
		}
	} while (!e);

	/* Undo too much lookahead.  The next read will be byte aligned so we
	 * can discard unused bits in the last meaningful byte.  */
	while (bk >= 8) {
		bk -= 8;
		ungetc((bb << bk), in_file);
	}

	/* flush out window */
	flush_window();

	/* return success */
	return 0;
}

/* ===========================================================================
 * Unzip in to out.  This routine works on both gzip and pkzip files.
 *
 * IN assertions: the buffer inbuf contains already the beginning of
 *   the compressed data, from offsets inptr to insize-1 included.
 *   The magic header has already been checked. The output buffer is cleared.
 * in, out: input and output file descriptors
 */
extern int unzip(FILE *l_in_file, FILE *l_out_file)
{
	const int extra_field = 0x04;	/* bit 2 set: extra field present */
	const int orig_name = 0x08;	/* bit 3 set: original file name present */
	const int comment = 0x10;	/* bit 4 set: file comment present */
	unsigned char buf[8];	/* extended local header */
	unsigned char flags;	/* compression flags */
	char magic[2];			/* magic header */
	int method;
	typedef void (*sig_type) (int);
	int exit_code=0;	/* program exit code */
	int i;

	in_file = l_in_file;
	out_file = l_out_file;

	if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
		(void) signal(SIGINT, (sig_type) abort_gzip);
	}
#ifdef SIGTERM
//	if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
//		(void) signal(SIGTERM, (sig_type) abort_gzip);
//	}
#endif
#ifdef SIGHUP
	if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
		(void) signal(SIGHUP, (sig_type) abort_gzip);
	}
#endif

	/* Allocate all global buffers (for DYN_ALLOC option) */
	window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
	outcnt = 0;
	bytes_out = 0L;

	magic[0] = fgetc(in_file);
	magic[1] = fgetc(in_file);

	/* Magic header for gzip files, 1F 8B = \037\213 */
	if (memcmp(magic, "\037\213", 2) != 0) {
		error_msg("Invalid gzip magic");
		return EXIT_FAILURE;
	}

	method = (int) fgetc(in_file);
	if (method != 8) {                   /* also catches EOF */
		error_msg("unknown method %d -- get newer version of gzip", method);
		exit_code = 1;
		return -1;
	}

	flags = (unsigned char) fgetc(in_file);

	/* Ignore time stamp(4), extra flags(1), OS type(1) */
	for (i = 0; i < 6; i++)
		fgetc(in_file);

	if ((flags & extra_field) != 0) {
		size_t extra;
		extra = fgetc(in_file);
		extra += fgetc(in_file) << 8;
		if (feof(in_file)) return 1;

		for (i = 0; i < extra; i++)
			fgetc(in_file);
	}

	/* Discard original name if any */
	if ((flags & orig_name) != 0) {
		while (fgetc(in_file) != 0 && !feof(in_file));	/* null */
	}

	/* Discard file comment if any */
	if ((flags & comment) != 0) {
		while (fgetc(in_file) != 0 && !feof(in_file));	/* null */
	}

	if (method < 0) {
		printf("it failed\n");
		return(exit_code);		/* error message already emitted */
	}

	make_crc_table();

	/* Decompress */
	if (method == 8) {

		int res = inflate();

		if (res == 3) {
			error_msg(memory_exhausted);
			exit_code = 1;
		} else if (res != 0) {
			error_msg("invalid compressed data--format violated");
			exit_code = 1;
		}

	} else {
		error_msg("internal error, invalid method");
		exit_code = 1;
	}

	/* Get the crc and original length
	 * crc32  (see algorithm.doc)
	 * uncompressed input size modulo 2^32
	 */
	fread(buf, 1, 8, in_file);

	/* Validate decompression - crc */
	if (!exit_code && (unsigned int)((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
		error_msg("invalid compressed data--crc error");
		exit_code = 1;
	}
	/* Validate decompression - size */
	if (!exit_code && ((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
		error_msg("invalid compressed data--length error");
		exit_code = 1;
	}

	free(window);
	free(crc_table);

	return exit_code;
}

/*
 * This needs access to global variables wondow and crc_table, so its not in its own file.
 */
extern void gz_close(int gunzip_pid)
{
	if (kill(gunzip_pid, SIGTERM) == -1) {
		error_msg_and_die("***  Couldnt kill old gunzip process *** aborting");
	}

	if (waitpid(gunzip_pid, NULL, 0) == -1) {
		printf("Couldnt wait ?");
	}
		free(window);
		free(crc_table);
}