xref: /openbmc/linux/lib/decompress_inflate.c (revision fd589a8f)
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 /* Included from initramfs et al code */
31 STATIC int INIT gunzip(unsigned char *buf, int len,
32 		       int(*fill)(void*, unsigned int),
33 		       int(*flush)(void*, unsigned int),
34 		       unsigned char *out_buf,
35 		       int *pos,
36 		       void(*error_fn)(char *x)) {
37 	u8 *zbuf;
38 	struct z_stream_s *strm;
39 	int rc;
40 	size_t out_len;
41 
42 	set_error_fn(error_fn);
43 	rc = -1;
44 	if (flush) {
45 		out_len = 0x8000; /* 32 K */
46 		out_buf = malloc(out_len);
47 	} else {
48 		out_len = 0x7fffffff; /* no limit */
49 	}
50 	if (!out_buf) {
51 		error("Out of memory while allocating output buffer");
52 		goto gunzip_nomem1;
53 	}
54 
55 	if (buf)
56 		zbuf = buf;
57 	else {
58 		zbuf = malloc(GZIP_IOBUF_SIZE);
59 		len = 0;
60 	}
61 	if (!zbuf) {
62 		error("Out of memory while allocating input buffer");
63 		goto gunzip_nomem2;
64 	}
65 
66 	strm = malloc(sizeof(*strm));
67 	if (strm == NULL) {
68 		error("Out of memory while allocating z_stream");
69 		goto gunzip_nomem3;
70 	}
71 
72 	strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
73 				 sizeof(struct inflate_state));
74 	if (strm->workspace == NULL) {
75 		error("Out of memory while allocating workspace");
76 		goto gunzip_nomem4;
77 	}
78 
79 	if (len == 0)
80 		len = fill(zbuf, GZIP_IOBUF_SIZE);
81 
82 	/* verify the gzip header */
83 	if (len < 10 ||
84 	   zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
85 		if (pos)
86 			*pos = 0;
87 		error("Not a gzip file");
88 		goto gunzip_5;
89 	}
90 
91 	/* skip over gzip header (1f,8b,08... 10 bytes total +
92 	 * possible asciz filename)
93 	 */
94 	strm->next_in = zbuf + 10;
95 	/* skip over asciz filename */
96 	if (zbuf[3] & 0x8) {
97 		while (strm->next_in[0])
98 			strm->next_in++;
99 		strm->next_in++;
100 	}
101 	strm->avail_in = len - (strm->next_in - zbuf);
102 
103 	strm->next_out = out_buf;
104 	strm->avail_out = out_len;
105 
106 	rc = zlib_inflateInit2(strm, -MAX_WBITS);
107 
108 	if (!flush) {
109 		WS(strm)->inflate_state.wsize = 0;
110 		WS(strm)->inflate_state.window = NULL;
111 	}
112 
113 	while (rc == Z_OK) {
114 		if (strm->avail_in == 0) {
115 			/* TODO: handle case where both pos and fill are set */
116 			len = fill(zbuf, GZIP_IOBUF_SIZE);
117 			if (len < 0) {
118 				rc = -1;
119 				error("read error");
120 				break;
121 			}
122 			strm->next_in = zbuf;
123 			strm->avail_in = len;
124 		}
125 		rc = zlib_inflate(strm, 0);
126 
127 		/* Write any data generated */
128 		if (flush && strm->next_out > out_buf) {
129 			int l = strm->next_out - out_buf;
130 			if (l != flush(out_buf, l)) {
131 				rc = -1;
132 				error("write error");
133 				break;
134 			}
135 			strm->next_out = out_buf;
136 			strm->avail_out = out_len;
137 		}
138 
139 		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
140 		if (rc == Z_STREAM_END) {
141 			rc = 0;
142 			break;
143 		} else if (rc != Z_OK) {
144 			error("uncompression error");
145 			rc = -1;
146 		}
147 	}
148 
149 	zlib_inflateEnd(strm);
150 	if (pos)
151 		/* add + 8 to skip over trailer */
152 		*pos = strm->next_in - zbuf+8;
153 
154 gunzip_5:
155 	free(strm->workspace);
156 gunzip_nomem4:
157 	free(strm);
158 gunzip_nomem3:
159 	if (!buf)
160 		free(zbuf);
161 gunzip_nomem2:
162 	if (flush)
163 		free(out_buf);
164 gunzip_nomem1:
165 	return rc; /* returns Z_OK (0) if successful */
166 }
167 
168 #define decompress gunzip
169