Root/lib/decompress_unlz4.c

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, int in_len,
35                int (*fill) (void *, unsigned int),
36                int (*flush) (void *, unsigned int),
37                u8 *output, int *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    int 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        fill(inp, 4);
88
89    chunksize = get_unaligned_le32(inp);
90    if (chunksize == ARCHIVE_MAGICNUMBER) {
91        inp += 4;
92        size -= 4;
93    } else {
94        error("invalid header");
95        goto exit_2;
96    }
97
98    if (posp)
99        *posp += 4;
100
101    for (;;) {
102
103        if (fill)
104            fill(inp, 4);
105
106        chunksize = get_unaligned_le32(inp);
107        if (chunksize == ARCHIVE_MAGICNUMBER) {
108            inp += 4;
109            size -= 4;
110            if (posp)
111                *posp += 4;
112            continue;
113        }
114        inp += 4;
115        size -= 4;
116
117        if (posp)
118            *posp += 4;
119
120        if (fill) {
121            if (chunksize > lz4_compressbound(uncomp_chunksize)) {
122                error("chunk length is longer than allocated");
123                goto exit_2;
124            }
125            fill(inp, chunksize);
126        }
127#ifdef PREBOOT
128        if (out_len >= uncomp_chunksize) {
129            dest_len = uncomp_chunksize;
130            out_len -= dest_len;
131        } else
132            dest_len = out_len;
133        ret = lz4_decompress(inp, &chunksize, outp, dest_len);
134#else
135        dest_len = uncomp_chunksize;
136        ret = lz4_decompress_unknownoutputsize(inp, chunksize, outp,
137                &dest_len);
138#endif
139        if (ret < 0) {
140            error("Decoding failed");
141            goto exit_2;
142        }
143
144        if (flush && flush(outp, dest_len) != dest_len)
145            goto exit_2;
146        if (output)
147            outp += dest_len;
148        if (posp)
149            *posp += chunksize;
150
151        size -= chunksize;
152
153        if (size == 0)
154            break;
155        else if (size < 0) {
156            error("data corrupted");
157            goto exit_2;
158        }
159
160        inp += chunksize;
161        if (fill)
162            inp = inp_start;
163    }
164
165    ret = 0;
166exit_2:
167    if (!input)
168        large_free(inp_start);
169exit_1:
170    if (!output)
171        large_free(outp);
172exit_0:
173    return ret;
174}
175
176#ifdef PREBOOT
177STATIC int INIT decompress(unsigned char *buf, int in_len,
178                  int(*fill)(void*, unsigned int),
179                  int(*flush)(void*, unsigned int),
180                  unsigned char *output,
181                  int *posp,
182                  void(*error)(char *x)
183    )
184{
185    return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
186}
187#endif
188

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