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
34STATIC 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;
188exit_2:
189	if (!input)
190		large_free(inp_start);
191exit_1:
192	if (!output)
193		large_free(outp);
194exit_0:
195	return ret;
196}
197
198#ifdef PREBOOT
199STATIC 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, long out_len,
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