xref: /linux/lib/decompress_inflate.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 #ifdef STATIC
2 /* Pre-boot environment: included */
3 
4 /* prevent inclusion of _LINUX_KERNEL_H in pre-boot environment: lots
5  * errors about console_printk etc... on ARM */
6 #define _LINUX_KERNEL_H
7 
8 #include "zlib_inflate/inftrees.c"
9 #include "zlib_inflate/inffast.c"
10 #include "zlib_inflate/inflate.c"
11 
12 #else /* STATIC */
13 /* initramfs et al: linked */
14 
15 #include <linux/zutil.h>
16 
17 #include "zlib_inflate/inftrees.h"
18 #include "zlib_inflate/inffast.h"
19 #include "zlib_inflate/inflate.h"
20 
21 #include "zlib_inflate/infutil.h"
22 
23 #endif /* STATIC */
24 
25 #include <linux/decompress/mm.h>
26 
27 #define GZIP_IOBUF_SIZE (16*1024)
28 
29 static int INIT nofill(void *buffer, unsigned int len)
30 {
31 	return -1;
32 }
33 
34 /* Included from initramfs et al code */
35 STATIC int INIT gunzip(unsigned char *buf, int len,
36 		       int(*fill)(void*, unsigned int),
37 		       int(*flush)(void*, unsigned int),
38 		       unsigned char *out_buf,
39 		       int *pos,
40 		       void(*error)(char *x)) {
41 	u8 *zbuf;
42 	struct z_stream_s *strm;
43 	int rc;
44 	size_t out_len;
45 
46 	rc = -1;
47 	if (flush) {
48 		out_len = 0x8000; /* 32 K */
49 		out_buf = malloc(out_len);
50 	} else {
51 		out_len = 0x7fffffff; /* no limit */
52 	}
53 	if (!out_buf) {
54 		error("Out of memory while allocating output buffer");
55 		goto gunzip_nomem1;
56 	}
57 
58 	if (buf)
59 		zbuf = buf;
60 	else {
61 		zbuf = malloc(GZIP_IOBUF_SIZE);
62 		len = 0;
63 	}
64 	if (!zbuf) {
65 		error("Out of memory while allocating input buffer");
66 		goto gunzip_nomem2;
67 	}
68 
69 	strm = malloc(sizeof(*strm));
70 	if (strm == NULL) {
71 		error("Out of memory while allocating z_stream");
72 		goto gunzip_nomem3;
73 	}
74 
75 	strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
76 				 sizeof(struct inflate_state));
77 	if (strm->workspace == NULL) {
78 		error("Out of memory while allocating workspace");
79 		goto gunzip_nomem4;
80 	}
81 
82 	if (!fill)
83 		fill = nofill;
84 
85 	if (len == 0)
86 		len = fill(zbuf, GZIP_IOBUF_SIZE);
87 
88 	/* verify the gzip header */
89 	if (len < 10 ||
90 	   zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
91 		if (pos)
92 			*pos = 0;
93 		error("Not a gzip file");
94 		goto gunzip_5;
95 	}
96 
97 	/* skip over gzip header (1f,8b,08... 10 bytes total +
98 	 * possible asciz filename)
99 	 */
100 	strm->next_in = zbuf + 10;
101 	strm->avail_in = len - 10;
102 	/* skip over asciz filename */
103 	if (zbuf[3] & 0x8) {
104 		do {
105 			/*
106 			 * If the filename doesn't fit into the buffer,
107 			 * the file is very probably corrupt. Don't try
108 			 * to read more data.
109 			 */
110 			if (strm->avail_in == 0) {
111 				error("header error");
112 				goto gunzip_5;
113 			}
114 			--strm->avail_in;
115 		} while (*strm->next_in++);
116 	}
117 
118 	strm->next_out = out_buf;
119 	strm->avail_out = out_len;
120 
121 	rc = zlib_inflateInit2(strm, -MAX_WBITS);
122 
123 	if (!flush) {
124 		WS(strm)->inflate_state.wsize = 0;
125 		WS(strm)->inflate_state.window = NULL;
126 	}
127 
128 	while (rc == Z_OK) {
129 		if (strm->avail_in == 0) {
130 			/* TODO: handle case where both pos and fill are set */
131 			len = fill(zbuf, GZIP_IOBUF_SIZE);
132 			if (len < 0) {
133 				rc = -1;
134 				error("read error");
135 				break;
136 			}
137 			strm->next_in = zbuf;
138 			strm->avail_in = len;
139 		}
140 		rc = zlib_inflate(strm, 0);
141 
142 		/* Write any data generated */
143 		if (flush && strm->next_out > out_buf) {
144 			int l = strm->next_out - out_buf;
145 			if (l != flush(out_buf, l)) {
146 				rc = -1;
147 				error("write error");
148 				break;
149 			}
150 			strm->next_out = out_buf;
151 			strm->avail_out = out_len;
152 		}
153 
154 		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
155 		if (rc == Z_STREAM_END) {
156 			rc = 0;
157 			break;
158 		} else if (rc != Z_OK) {
159 			error("uncompression error");
160 			rc = -1;
161 		}
162 	}
163 
164 	zlib_inflateEnd(strm);
165 	if (pos)
166 		/* add + 8 to skip over trailer */
167 		*pos = strm->next_in - zbuf+8;
168 
169 gunzip_5:
170 	free(strm->workspace);
171 gunzip_nomem4:
172 	free(strm);
173 gunzip_nomem3:
174 	if (!buf)
175 		free(zbuf);
176 gunzip_nomem2:
177 	if (flush)
178 		free(out_buf);
179 gunzip_nomem1:
180 	return rc; /* returns Z_OK (0) if successful */
181 }
182 
183 #define decompress gunzip
184