xref: /openbmc/linux/lib/decompress_unlz4.c (revision 275876e2)
1 /*
2  * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
3  *
4  * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #ifdef STATIC
12 #define PREBOOT
13 #include "lz4/lz4_decompress.c"
14 #else
15 #include <linux/decompress/unlz4.h>
16 #endif
17 #include <linux/types.h>
18 #include <linux/lz4.h>
19 #include <linux/decompress/mm.h>
20 #include <linux/compiler.h>
21 
22 #include <asm/unaligned.h>
23 
24 /*
25  * Note: Uncompressed chunk size is used in the compressor side
26  * (userspace side for compression).
27  * It is hardcoded because there is not proper way to extract it
28  * from the binary stream which is generated by the preliminary
29  * version of LZ4 tool so far.
30  */
31 #define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
32 #define ARCHIVE_MAGICNUMBER 0x184C2102
33 
34 STATIC inline int INIT unlz4(u8 *input, long in_len,
35 				long (*fill)(void *, unsigned long),
36 				long (*flush)(void *, unsigned long),
37 				u8 *output, long *posp,
38 				void (*error) (char *x))
39 {
40 	int ret = -1;
41 	size_t chunksize = 0;
42 	size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
43 	u8 *inp;
44 	u8 *inp_start;
45 	u8 *outp;
46 	long size = in_len;
47 #ifdef PREBOOT
48 	size_t out_len = get_unaligned_le32(input + in_len);
49 #endif
50 	size_t dest_len;
51 
52 
53 	if (output) {
54 		outp = output;
55 	} else if (!flush) {
56 		error("NULL output pointer and no flush function provided");
57 		goto exit_0;
58 	} else {
59 		outp = large_malloc(uncomp_chunksize);
60 		if (!outp) {
61 			error("Could not allocate output buffer");
62 			goto exit_0;
63 		}
64 	}
65 
66 	if (input && fill) {
67 		error("Both input pointer and fill function provided,");
68 		goto exit_1;
69 	} else if (input) {
70 		inp = input;
71 	} else if (!fill) {
72 		error("NULL input pointer and missing fill function");
73 		goto exit_1;
74 	} else {
75 		inp = large_malloc(lz4_compressbound(uncomp_chunksize));
76 		if (!inp) {
77 			error("Could not allocate input buffer");
78 			goto exit_1;
79 		}
80 	}
81 	inp_start = inp;
82 
83 	if (posp)
84 		*posp = 0;
85 
86 	if (fill) {
87 		size = fill(inp, 4);
88 		if (size < 4) {
89 			error("data corrupted");
90 			goto exit_2;
91 		}
92 	}
93 
94 	chunksize = get_unaligned_le32(inp);
95 	if (chunksize == ARCHIVE_MAGICNUMBER) {
96 		if (!fill) {
97 			inp += 4;
98 			size -= 4;
99 		}
100 	} else {
101 		error("invalid header");
102 		goto exit_2;
103 	}
104 
105 	if (posp)
106 		*posp += 4;
107 
108 	for (;;) {
109 
110 		if (fill) {
111 			size = fill(inp, 4);
112 			if (size == 0)
113 				break;
114 			if (size < 4) {
115 				error("data corrupted");
116 				goto exit_2;
117 			}
118 		}
119 
120 		chunksize = get_unaligned_le32(inp);
121 		if (chunksize == ARCHIVE_MAGICNUMBER) {
122 			if (!fill) {
123 				inp += 4;
124 				size -= 4;
125 			}
126 			if (posp)
127 				*posp += 4;
128 			continue;
129 		}
130 
131 
132 		if (posp)
133 			*posp += 4;
134 
135 		if (!fill) {
136 			inp += 4;
137 			size -= 4;
138 		} else {
139 			if (chunksize > lz4_compressbound(uncomp_chunksize)) {
140 				error("chunk length is longer than allocated");
141 				goto exit_2;
142 			}
143 			size = fill(inp, chunksize);
144 			if (size < chunksize) {
145 				error("data corrupted");
146 				goto exit_2;
147 			}
148 		}
149 #ifdef PREBOOT
150 		if (out_len >= uncomp_chunksize) {
151 			dest_len = uncomp_chunksize;
152 			out_len -= dest_len;
153 		} else
154 			dest_len = out_len;
155 		ret = lz4_decompress(inp, &chunksize, outp, dest_len);
156 #else
157 		dest_len = uncomp_chunksize;
158 		ret = lz4_decompress_unknownoutputsize(inp, chunksize, outp,
159 				&dest_len);
160 #endif
161 		if (ret < 0) {
162 			error("Decoding failed");
163 			goto exit_2;
164 		}
165 
166 		ret = -1;
167 		if (flush && flush(outp, dest_len) != dest_len)
168 			goto exit_2;
169 		if (output)
170 			outp += dest_len;
171 		if (posp)
172 			*posp += chunksize;
173 
174 		if (!fill) {
175 			size -= chunksize;
176 
177 			if (size == 0)
178 				break;
179 			else if (size < 0) {
180 				error("data corrupted");
181 				goto exit_2;
182 			}
183 			inp += chunksize;
184 		}
185 	}
186 
187 	ret = 0;
188 exit_2:
189 	if (!input)
190 		large_free(inp_start);
191 exit_1:
192 	if (!output)
193 		large_free(outp);
194 exit_0:
195 	return ret;
196 }
197 
198 #ifdef PREBOOT
199 STATIC int INIT decompress(unsigned char *buf, long in_len,
200 			      long (*fill)(void*, unsigned long),
201 			      long (*flush)(void*, unsigned long),
202 			      unsigned char *output,
203 			      long *posp,
204 			      void(*error)(char *x)
205 	)
206 {
207 	return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
208 }
209 #endif
210