summaryrefslogtreecommitdiff
path: root/lib/decompress_inflate.c
blob: 19ff89e34eec6b7aaec3d47b4a13aac9d6d70c1f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
#ifdef STATIC
/* Pre-boot environment: included */

/* prevent inclusion of _LINUX_KERNEL_H in pre-boot environment: lots
 * errors about console_printk etc... on ARM */
#define _LINUX_KERNEL_H

#include "zlib_inflate/inftrees.c"
#include "zlib_inflate/inffast.c"
#include "zlib_inflate/inflate.c"

#else /* STATIC */
/* initramfs et al: linked */

#include <linux/zutil.h>

#include "zlib_inflate/inftrees.h"
#include "zlib_inflate/inffast.h"
#include "zlib_inflate/inflate.h"

#include "zlib_inflate/infutil.h"

#endif /* STATIC */

#include <linux/decompress/mm.h>

#define GZIP_IOBUF_SIZE (16*1024)

static int INIT nofill(void *buffer, unsigned int len)
{
	return -1;
}

/* Included from initramfs et al code */
STATIC int INIT gunzip(unsigned char *buf, int len,
		       int(*fill)(void*, unsigned int),
		       int(*flush)(void*, unsigned int),
		       unsigned char *out_buf,
		       int *pos,
		       void(*error)(char *x)) {
	u8 *zbuf;
	struct z_stream_s *strm;
	int rc;
	size_t out_len;

	rc = -1;
	if (flush) {
		out_len = 0x8000; /* 32 K */
		out_buf = malloc(out_len);
	} else {
		out_len = 0x7fffffff; /* no limit */
	}
	if (!out_buf) {
		error("Out of memory while allocating output buffer");
		goto gunzip_nomem1;
	}

	if (buf)
		zbuf = buf;
	else {
		zbuf = malloc(GZIP_IOBUF_SIZE);
		len = 0;
	}
	if (!zbuf) {
		error("Out of memory while allocating input buffer");
		goto gunzip_nomem2;
	}

	strm = malloc(sizeof(*strm));
	if (strm == NULL) {
		error("Out of memory while allocating z_stream");
		goto gunzip_nomem3;
	}

	strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
				 sizeof(struct inflate_state));
	if (strm->workspace == NULL) {
		error("Out of memory while allocating workspace");
		goto gunzip_nomem4;
	}

	if (!fill)
		fill = nofill;

	if (len == 0)
		len = fill(zbuf, GZIP_IOBUF_SIZE);

	/* verify the gzip header */
	if (len < 10 ||
	   zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
		if (pos)
			*pos = 0;
		error("Not a gzip file");
		goto gunzip_5;
	}

	/* skip over gzip header (1f,8b,08... 10 bytes total +
	 * possible asciz filename)
	 */
	strm->next_in = zbuf + 10;
	strm->avail_in = len - 10;
	/* skip over asciz filename */
	if (zbuf[3] & 0x8) {
		do {
			/*
			 * If the filename doesn't fit into the buffer,
			 * the file is very probably corrupt. Don't try
			 * to read more data.
			 */
			if (strm->avail_in == 0) {
				error("header error");
				goto gunzip_5;
			}
			--strm->avail_in;
		} while (*strm->next_in++);
	}

	strm->next_out = out_buf;
	strm->avail_out = out_len;

	rc = zlib_inflateInit2(strm, -MAX_WBITS);

	if (!flush) {
		WS(strm)->inflate_state.wsize = 0;
		WS(strm)->inflate_state.window = NULL;
	}

	while (rc == Z_OK) {
		if (strm->avail_in == 0) {
			/* TODO: handle case where both pos and fill are set */
			len = fill(zbuf, GZIP_IOBUF_SIZE);
			if (len < 0) {
				rc = -1;
				error("read error");
				break;
			}
			strm->next_in = zbuf;
			strm->avail_in = len;
		}
		rc = zlib_inflate(strm, 0);

		/* Write any data generated */
		if (flush && strm->next_out > out_buf) {
			int l = strm->next_out - out_buf;
			if (l != flush(out_buf, l)) {
				rc = -1;
				error("write error");
				break;
			}
			strm->next_out = out_buf;
			strm->avail_out = out_len;
		}

		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
		if (rc == Z_STREAM_END) {
			rc = 0;
			break;
		} else if (rc != Z_OK) {
			error("uncompression error");
			rc = -1;
		}
	}

	zlib_inflateEnd(strm);
	if (pos)
		/* add + 8 to skip over trailer */
		*pos = strm->next_in - zbuf+8;

gunzip_5:
	free(strm->workspace);
gunzip_nomem4:
	free(strm);
gunzip_nomem3:
	if (!buf)
		free(zbuf);
gunzip_nomem2:
	if (flush)
		free(out_buf);
gunzip_nomem1:
	return rc; /* returns Z_OK (0) if successful */
}

#define decompress gunzip