1 // SPDX-License-Identifier: GPL-2.0
2 #include <errno.h>
3 #include <lzma.h>
4 #include <stdio.h>
5 #include <linux/compiler.h>
6 #include <sys/types.h>
7 #include <sys/stat.h>
8 #include <fcntl.h>
9 #include "compress.h"
10 #include "debug.h"
11 #include <string.h>
12 #include <unistd.h>
13 #include <internal/lib.h>
14 
15 #define BUFSIZE 8192
16 
lzma_strerror(lzma_ret ret)17 static const char *lzma_strerror(lzma_ret ret)
18 {
19 	switch ((int) ret) {
20 	case LZMA_MEM_ERROR:
21 		return "Memory allocation failed";
22 	case LZMA_OPTIONS_ERROR:
23 		return "Unsupported decompressor flags";
24 	case LZMA_FORMAT_ERROR:
25 		return "The input is not in the .xz format";
26 	case LZMA_DATA_ERROR:
27 		return "Compressed file is corrupt";
28 	case LZMA_BUF_ERROR:
29 		return "Compressed file is truncated or otherwise corrupt";
30 	default:
31 		return "Unknown error, possibly a bug";
32 	}
33 }
34 
lzma_decompress_to_file(const char * input,int output_fd)35 int lzma_decompress_to_file(const char *input, int output_fd)
36 {
37 	lzma_action action = LZMA_RUN;
38 	lzma_stream strm   = LZMA_STREAM_INIT;
39 	lzma_ret ret;
40 	int err = -1;
41 
42 	u8 buf_in[BUFSIZE];
43 	u8 buf_out[BUFSIZE];
44 	FILE *infile;
45 
46 	infile = fopen(input, "rb");
47 	if (!infile) {
48 		pr_err("lzma: fopen failed on %s: '%s'\n",
49 		       input, strerror(errno));
50 		return -1;
51 	}
52 
53 	ret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
54 	if (ret != LZMA_OK) {
55 		pr_err("lzma: lzma_stream_decoder failed %s (%d)\n",
56 			lzma_strerror(ret), ret);
57 		goto err_fclose;
58 	}
59 
60 	strm.next_in   = NULL;
61 	strm.avail_in  = 0;
62 	strm.next_out  = buf_out;
63 	strm.avail_out = sizeof(buf_out);
64 
65 	while (1) {
66 		if (strm.avail_in == 0 && !feof(infile)) {
67 			strm.next_in  = buf_in;
68 			strm.avail_in = fread(buf_in, 1, sizeof(buf_in), infile);
69 
70 			if (ferror(infile)) {
71 				pr_err("lzma: read error: %s\n", strerror(errno));
72 				goto err_lzma_end;
73 			}
74 
75 			if (feof(infile))
76 				action = LZMA_FINISH;
77 		}
78 
79 		ret = lzma_code(&strm, action);
80 
81 		if (strm.avail_out == 0 || ret == LZMA_STREAM_END) {
82 			ssize_t write_size = sizeof(buf_out) - strm.avail_out;
83 
84 			if (writen(output_fd, buf_out, write_size) != write_size) {
85 				pr_err("lzma: write error: %s\n", strerror(errno));
86 				goto err_lzma_end;
87 			}
88 
89 			strm.next_out  = buf_out;
90 			strm.avail_out = sizeof(buf_out);
91 		}
92 
93 		if (ret != LZMA_OK) {
94 			if (ret == LZMA_STREAM_END)
95 				break;
96 
97 			pr_err("lzma: failed %s\n", lzma_strerror(ret));
98 			goto err_lzma_end;
99 		}
100 	}
101 
102 	err = 0;
103 err_lzma_end:
104 	lzma_end(&strm);
105 err_fclose:
106 	fclose(infile);
107 	return err;
108 }
109 
lzma_is_compressed(const char * input)110 bool lzma_is_compressed(const char *input)
111 {
112 	int fd = open(input, O_RDONLY);
113 	const uint8_t magic[6] = { 0xFD, '7', 'z', 'X', 'Z', 0x00 };
114 	char buf[6] = { 0 };
115 	ssize_t rc;
116 
117 	if (fd < 0)
118 		return -1;
119 
120 	rc = read(fd, buf, sizeof(buf));
121 	close(fd);
122 	return rc == sizeof(buf) ?
123 	       memcmp(buf, magic, sizeof(buf)) == 0 : false;
124 }
125