xref: /openbmc/linux/lib/decompress_inflate.c (revision e8e0929d)
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/slab.h>
23 
24 #endif /* STATIC */
25 
26 #include <linux/decompress/mm.h>
27 
28 #define GZIP_IOBUF_SIZE (16*1024)
29 
30 static int nofill(void *buffer, unsigned int len)
31 {
32 	return -1;
33 }
34 
35 /* Included from initramfs et al code */
36 STATIC int INIT gunzip(unsigned char *buf, int len,
37 		       int(*fill)(void*, unsigned int),
38 		       int(*flush)(void*, unsigned int),
39 		       unsigned char *out_buf,
40 		       int *pos,
41 		       void(*error_fn)(char *x)) {
42 	u8 *zbuf;
43 	struct z_stream_s *strm;
44 	int rc;
45 	size_t out_len;
46 
47 	set_error_fn(error_fn);
48 	rc = -1;
49 	if (flush) {
50 		out_len = 0x8000; /* 32 K */
51 		out_buf = malloc(out_len);
52 	} else {
53 		out_len = 0x7fffffff; /* no limit */
54 	}
55 	if (!out_buf) {
56 		error("Out of memory while allocating output buffer");
57 		goto gunzip_nomem1;
58 	}
59 
60 	if (buf)
61 		zbuf = buf;
62 	else {
63 		zbuf = malloc(GZIP_IOBUF_SIZE);
64 		len = 0;
65 	}
66 	if (!zbuf) {
67 		error("Out of memory while allocating input buffer");
68 		goto gunzip_nomem2;
69 	}
70 
71 	strm = malloc(sizeof(*strm));
72 	if (strm == NULL) {
73 		error("Out of memory while allocating z_stream");
74 		goto gunzip_nomem3;
75 	}
76 
77 	strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
78 				 sizeof(struct inflate_state));
79 	if (strm->workspace == NULL) {
80 		error("Out of memory while allocating workspace");
81 		goto gunzip_nomem4;
82 	}
83 
84 	if (!fill)
85 		fill = nofill;
86 
87 	if (len == 0)
88 		len = fill(zbuf, GZIP_IOBUF_SIZE);
89 
90 	/* verify the gzip header */
91 	if (len < 10 ||
92 	   zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
93 		if (pos)
94 			*pos = 0;
95 		error("Not a gzip file");
96 		goto gunzip_5;
97 	}
98 
99 	/* skip over gzip header (1f,8b,08... 10 bytes total +
100 	 * possible asciz filename)
101 	 */
102 	strm->next_in = zbuf + 10;
103 	/* skip over asciz filename */
104 	if (zbuf[3] & 0x8) {
105 		while (strm->next_in[0])
106 			strm->next_in++;
107 		strm->next_in++;
108 	}
109 	strm->avail_in = len - (strm->next_in - zbuf);
110 
111 	strm->next_out = out_buf;
112 	strm->avail_out = out_len;
113 
114 	rc = zlib_inflateInit2(strm, -MAX_WBITS);
115 
116 	if (!flush) {
117 		WS(strm)->inflate_state.wsize = 0;
118 		WS(strm)->inflate_state.window = NULL;
119 	}
120 
121 	while (rc == Z_OK) {
122 		if (strm->avail_in == 0) {
123 			/* TODO: handle case where both pos and fill are set */
124 			len = fill(zbuf, GZIP_IOBUF_SIZE);
125 			if (len < 0) {
126 				rc = -1;
127 				error("read error");
128 				break;
129 			}
130 			strm->next_in = zbuf;
131 			strm->avail_in = len;
132 		}
133 		rc = zlib_inflate(strm, 0);
134 
135 		/* Write any data generated */
136 		if (flush && strm->next_out > out_buf) {
137 			int l = strm->next_out - out_buf;
138 			if (l != flush(out_buf, l)) {
139 				rc = -1;
140 				error("write error");
141 				break;
142 			}
143 			strm->next_out = out_buf;
144 			strm->avail_out = out_len;
145 		}
146 
147 		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
148 		if (rc == Z_STREAM_END) {
149 			rc = 0;
150 			break;
151 		} else if (rc != Z_OK) {
152 			error("uncompression error");
153 			rc = -1;
154 		}
155 	}
156 
157 	zlib_inflateEnd(strm);
158 	if (pos)
159 		/* add + 8 to skip over trailer */
160 		*pos = strm->next_in - zbuf+8;
161 
162 gunzip_5:
163 	free(strm->workspace);
164 gunzip_nomem4:
165 	free(strm);
166 gunzip_nomem3:
167 	if (!buf)
168 		free(zbuf);
169 gunzip_nomem2:
170 	if (flush)
171 		free(out_buf);
172 gunzip_nomem1:
173 	return rc; /* returns Z_OK (0) if successful */
174 }
175 
176 #define decompress gunzip
177