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unxz.c revision 1.5 
      1 /*	$NetBSD: unxz.c,v 1.5 2011/09/30 01:32:21 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2011 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 #include <sys/cdefs.h>
     39 __RCSID("$NetBSD: unxz.c,v 1.5 2011/09/30 01:32:21 christos Exp $");
     40 
     41 #include <stdarg.h>
     42 #include <errno.h>
     43 #include <stdio.h>
     44 #include <unistd.h>
     45 #include <lzma.h>
     46 
     47 static off_t
     48 unxz(int i, int o, char *pre, size_t prelen, off_t *bytes_in)
     49 {
     50 	lzma_stream strm = LZMA_STREAM_INIT;
     51 	static const int flags = LZMA_TELL_UNSUPPORTED_CHECK|LZMA_CONCATENATED;
     52 	lzma_ret ret;
     53 	lzma_action action = LZMA_RUN;
     54 	off_t bytes_out, bp;
     55 	uint8_t ibuf[BUFSIZ];
     56 	uint8_t obuf[BUFSIZ];
     57 
     58 	if (bytes_in == NULL)
     59 		bytes_in = &bp;
     60 
     61 	strm.next_in = ibuf;
     62 	memcpy(ibuf, pre, prelen);
     63 	strm.avail_in = read(i, ibuf + prelen, sizeof(ibuf) - prelen);
     64 	if (strm.avail_in == (size_t)-1)
     65 		maybe_err("read failed");
     66 	strm.avail_in += prelen;
     67 	*bytes_in = strm.avail_in;
     68 
     69 	if ((ret = lzma_stream_decoder(&strm, UINT64_MAX, flags)) != LZMA_OK)
     70 		maybe_errx("Can't initialize decoder (%d)", ret);
     71 
     72 	strm.next_out = NULL;
     73 	strm.avail_out = 0;
     74 	if ((ret = lzma_code(&strm, LZMA_RUN)) != LZMA_OK)
     75 		maybe_errx("Can't read headers (%d)", ret);
     76 
     77 	bytes_out = 0;
     78 	strm.next_out = obuf;
     79 	strm.avail_out = sizeof(obuf);
     80 
     81 	for (;;) {
     82 		if (strm.avail_in == 0) {
     83 			strm.next_in = ibuf;
     84 			strm.avail_in = read(i, ibuf, sizeof(ibuf));
     85 			switch (strm.avail_in) {
     86 			case (size_t)-1:
     87 				maybe_err("read failed");
     88 				/*NOTREACHED*/
     89 			case 0:
     90 				action = LZMA_FINISH;
     91 				break;
     92 			default:
     93 				*bytes_in += strm.avail_in;
     94 				break;
     95 			}
     96 		}
     97 
     98 		ret = lzma_code(&strm, action);
     99 
    100 		// Write and check write error before checking decoder error.
    101 		// This way as much data as possible gets written to output
    102 		// even if decoder detected an error.
    103 		if (strm.avail_out == 0 || ret != LZMA_OK) {
    104 			const size_t write_size = sizeof(obuf) - strm.avail_out;
    105 
    106 			if (write(o, obuf, write_size) != (ssize_t)write_size)
    107 				maybe_err("write failed");
    108 
    109 			strm.next_out = obuf;
    110 			strm.avail_out = sizeof(obuf);
    111 			bytes_out += write_size;
    112 		}
    113 
    114 		if (ret != LZMA_OK) {
    115 			if (ret == LZMA_STREAM_END) {
    116 				// Check that there's no trailing garbage.
    117 				if (strm.avail_in != 0 || read(i, ibuf, 1))
    118 					ret = LZMA_DATA_ERROR;
    119 				else {
    120 					lzma_end(&strm);
    121 					return bytes_out;
    122 				}
    123 			}
    124 
    125 			const char *msg;
    126 			switch (ret) {
    127 			case LZMA_MEM_ERROR:
    128 				msg = strerror(ENOMEM);
    129 				break;
    130 
    131 			case LZMA_FORMAT_ERROR:
    132 				msg = "File format not recognized";
    133 				break;
    134 
    135 			case LZMA_OPTIONS_ERROR:
    136 				// FIXME: Better message?
    137 				msg = "Unsupported compression options";
    138 				break;
    139 
    140 			case LZMA_DATA_ERROR:
    141 				msg = "File is corrupt";
    142 				break;
    143 
    144 			case LZMA_BUF_ERROR:
    145 				msg = "Unexpected end of input";
    146 				break;
    147 
    148 			case LZMA_MEMLIMIT_ERROR:
    149 				msg = "Reached memory limit";
    150 				break;
    151 
    152 			default:
    153 				maybe_errx("Unknown error (%d)", ret);
    154 				break;
    155 			}
    156 			maybe_errx("%s", msg);
    157 
    158 		}
    159 	}
    160 }
    161