xref: /linux/lib/decompress_inflate.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
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 #include <linux/decompress/inflate.h>
23 
24 #endif /* STATIC */
25 
26 #include <linux/decompress/mm.h>
27 
28 #define GZIP_IOBUF_SIZE (16*1024)
29 
30 static long INIT nofill(void *buffer, unsigned long len)
31 {
32 	return -1;
33 }
34 
35 /* Included from initramfs et al code */
36 STATIC int INIT gunzip(unsigned char *buf, long len,
37 		       long (*fill)(void*, unsigned long),
38 		       long (*flush)(void*, unsigned long),
39 		       unsigned char *out_buf,
40 		       long *pos,
41 		       void(*error)(char *x)) {
42 	u8 *zbuf;
43 	struct z_stream_s *strm;
44 	int rc;
45 	size_t out_len;
46 
47 	rc = -1;
48 	if (flush) {
49 		out_len = 0x8000; /* 32 K */
50 		out_buf = malloc(out_len);
51 	} else {
52 		out_len = ((size_t)~0) - (size_t)out_buf; /* no limit */
53 	}
54 	if (!out_buf) {
55 		error("Out of memory while allocating output buffer");
56 		goto gunzip_nomem1;
57 	}
58 
59 	if (buf)
60 		zbuf = buf;
61 	else {
62 		zbuf = malloc(GZIP_IOBUF_SIZE);
63 		len = 0;
64 	}
65 	if (!zbuf) {
66 		error("Out of memory while allocating input buffer");
67 		goto gunzip_nomem2;
68 	}
69 
70 	strm = malloc(sizeof(*strm));
71 	if (strm == NULL) {
72 		error("Out of memory while allocating z_stream");
73 		goto gunzip_nomem3;
74 	}
75 
76 	strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
77 				 sizeof(struct inflate_state));
78 	if (strm->workspace == NULL) {
79 		error("Out of memory while allocating workspace");
80 		goto gunzip_nomem4;
81 	}
82 
83 	if (!fill)
84 		fill = nofill;
85 
86 	if (len == 0)
87 		len = fill(zbuf, GZIP_IOBUF_SIZE);
88 
89 	/* verify the gzip header */
90 	if (len < 10 ||
91 	   zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
92 		if (pos)
93 			*pos = 0;
94 		error("Not a gzip file");
95 		goto gunzip_5;
96 	}
97 
98 	/* skip over gzip header (1f,8b,08... 10 bytes total +
99 	 * possible asciz filename)
100 	 */
101 	strm->next_in = zbuf + 10;
102 	strm->avail_in = len - 10;
103 	/* skip over asciz filename */
104 	if (zbuf[3] & 0x8) {
105 		do {
106 			/*
107 			 * If the filename doesn't fit into the buffer,
108 			 * the file is very probably corrupt. Don't try
109 			 * to read more data.
110 			 */
111 			if (strm->avail_in == 0) {
112 				error("header error");
113 				goto gunzip_5;
114 			}
115 			--strm->avail_in;
116 		} while (*strm->next_in++);
117 	}
118 
119 	strm->next_out = out_buf;
120 	strm->avail_out = out_len;
121 
122 	rc = zlib_inflateInit2(strm, -MAX_WBITS);
123 
124 	if (!flush) {
125 		WS(strm)->inflate_state.wsize = 0;
126 		WS(strm)->inflate_state.window = NULL;
127 	}
128 
129 	while (rc == Z_OK) {
130 		if (strm->avail_in == 0) {
131 			/* TODO: handle case where both pos and fill are set */
132 			len = fill(zbuf, GZIP_IOBUF_SIZE);
133 			if (len < 0) {
134 				rc = -1;
135 				error("read error");
136 				break;
137 			}
138 			strm->next_in = zbuf;
139 			strm->avail_in = len;
140 		}
141 		rc = zlib_inflate(strm, 0);
142 
143 		/* Write any data generated */
144 		if (flush && strm->next_out > out_buf) {
145 			long l = strm->next_out - out_buf;
146 			if (l != flush(out_buf, l)) {
147 				rc = -1;
148 				error("write error");
149 				break;
150 			}
151 			strm->next_out = out_buf;
152 			strm->avail_out = out_len;
153 		}
154 
155 		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
156 		if (rc == Z_STREAM_END) {
157 			rc = 0;
158 			break;
159 		} else if (rc != Z_OK) {
160 			error("uncompression error");
161 			rc = -1;
162 		}
163 	}
164 
165 	zlib_inflateEnd(strm);
166 	if (pos)
167 		/* add + 8 to skip over trailer */
168 		*pos = strm->next_in - zbuf+8;
169 
170 gunzip_5:
171 	free(strm->workspace);
172 gunzip_nomem4:
173 	free(strm);
174 gunzip_nomem3:
175 	if (!buf)
176 		free(zbuf);
177 gunzip_nomem2:
178 	if (flush)
179 		free(out_buf);
180 gunzip_nomem1:
181 	return rc; /* returns Z_OK (0) if successful */
182 }
183 
184 #define decompress gunzip
185