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 
22 static uint8_t in[BUFSIZ];
23 static uint8_t out[BUFSIZ];
24 
25 int 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 
141 error:
142 	xz_dec_end(s);
143 	fputs(argv[0], stderr);
144 	fputs(": ", stderr);
145 	fputs(msg, stderr);
146 	return 1;
147 }
148