1/*
2 * Simple XZ decoder command line tool
3 *
4 * Author: Lasse Collin <lasse.collin@tukaani.org>
5 *
6 * This file has been put into the public domain.
7 * You can do whatever you want with this file.
8 */
9
10/*
11 * This is really limited: Not all filters from .xz format are supported,
12 * only CRC32 is supported as the integrity check, and decoding of
13 * concatenated .xz streams is not supported. Thus, you may want to look
14 * at xzdec from XZ Utils if a few KiB bigger tool is not a problem.
15 */
16
17#include <stdbool.h>
18#include <stdio.h>
19#include <string.h>
20#include "xz.h"
21
22static uint8_t in[BUFSIZ];
23static uint8_t out[BUFSIZ];
24
25int main(int argc, char **argv)
26{
27	struct xz_buf b;
28	struct xz_dec *s;
29	enum xz_ret ret;
30	const char *msg;
31
32	if (argc >= 2 && strcmp(argv[1], "--help") == 0) {
33		fputs("Uncompress a .xz file from stdin to stdout.\n"
34				"Arguments other than `--help' are ignored.\n",
35				stdout);
36		return 0;
37	}
38
39	xz_crc32_init();
40#ifdef XZ_USE_CRC64
41	xz_crc64_init();
42#endif
43
44	/*
45	 * Support up to 64 MiB dictionary. The actually needed memory
46	 * is allocated once the headers have been parsed.
47	 */
48	s = xz_dec_init(XZ_DYNALLOC, 1 << 26);
49	if (s == NULL) {
50		msg = "Memory allocation failed\n";
51		goto error;
52	}
53
54	b.in = in;
55	b.in_pos = 0;
56	b.in_size = 0;
57	b.out = out;
58	b.out_pos = 0;
59	b.out_size = BUFSIZ;
60
61	while (true) {
62		if (b.in_pos == b.in_size) {
63			b.in_size = fread(in, 1, sizeof(in), stdin);
64
65			if (ferror(stdin)) {
66				msg = "Read error\n";
67				goto error;
68			}
69
70			b.in_pos = 0;
71		}
72
73		/*
74		 * There are a few ways to set the "finish" (the third)
75		 * argument. We could use feof(stdin) but testing in_size
76		 * is fine too and may also work in applications that don't
77		 * use FILEs.
78		 */
79		ret = xz_dec_catrun(s, &b, b.in_size == 0);
80
81		if (b.out_pos == sizeof(out)) {
82			if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos) {
83				msg = "Write error\n";
84				goto error;
85			}
86
87			b.out_pos = 0;
88		}
89
90		if (ret == XZ_OK)
91			continue;
92
93#ifdef XZ_DEC_ANY_CHECK
94		if (ret == XZ_UNSUPPORTED_CHECK) {
95			fputs(argv[0], stderr);
96			fputs(": ", stderr);
97			fputs("Unsupported check; not verifying "
98					"file integrity\n", stderr);
99			continue;
100		}
101#endif
102
103		if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos
104				|| fclose(stdout)) {
105			msg = "Write error\n";
106			goto error;
107		}
108
109		switch (ret) {
110		case XZ_STREAM_END:
111			xz_dec_end(s);
112			return 0;
113
114		case XZ_MEM_ERROR:
115			msg = "Memory allocation failed\n";
116			goto error;
117
118		case XZ_MEMLIMIT_ERROR:
119			msg = "Memory usage limit reached\n";
120			goto error;
121
122		case XZ_FORMAT_ERROR:
123			msg = "Not a .xz file\n";
124			goto error;
125
126		case XZ_OPTIONS_ERROR:
127			msg = "Unsupported options in the .xz headers\n";
128			goto error;
129
130		case XZ_DATA_ERROR:
131		case XZ_BUF_ERROR:
132			msg = "File is corrupt\n";
133			goto error;
134
135		default:
136			msg = "Bug!\n";
137			goto error;
138		}
139	}
140
141error:
142	xz_dec_end(s);
143	fputs(argv[0], stderr);
144	fputs(": ", stderr);
145	fputs(msg, stderr);
146	return 1;
147}
148