xref: /openbmc/linux/lib/decompress_inflate.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
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 INBUF_LEN (16*1024)
28 
29 /* Included from initramfs et al code */
30 STATIC int INIT gunzip(unsigned char *buf, int len,
31 		       int(*fill)(void*, unsigned int),
32 		       int(*flush)(void*, unsigned int),
33 		       unsigned char *out_buf,
34 		       int *pos,
35 		       void(*error_fn)(char *x)) {
36 	u8 *zbuf;
37 	struct z_stream_s *strm;
38 	int rc;
39 	size_t out_len;
40 
41 	set_error_fn(error_fn);
42 	rc = -1;
43 	if (flush) {
44 		out_len = 0x8000; /* 32 K */
45 		out_buf = malloc(out_len);
46 	} else {
47 		out_len = 0x7fffffff; /* no limit */
48 	}
49 	if (!out_buf) {
50 		error("Out of memory while allocating output buffer");
51 		goto gunzip_nomem1;
52 	}
53 
54 	if (buf)
55 		zbuf = buf;
56 	else {
57 		zbuf = malloc(INBUF_LEN);
58 		len = 0;
59 	}
60 	if (!zbuf) {
61 		error("Out of memory while allocating input buffer");
62 		goto gunzip_nomem2;
63 	}
64 
65 	strm = malloc(sizeof(*strm));
66 	if (strm == NULL) {
67 		error("Out of memory while allocating z_stream");
68 		goto gunzip_nomem3;
69 	}
70 
71 	strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
72 				 sizeof(struct inflate_state));
73 	if (strm->workspace == NULL) {
74 		error("Out of memory while allocating workspace");
75 		goto gunzip_nomem4;
76 	}
77 
78 	if (len == 0)
79 		len = fill(zbuf, INBUF_LEN);
80 
81 	/* verify the gzip header */
82 	if (len < 10 ||
83 	   zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
84 		if (pos)
85 			*pos = 0;
86 		error("Not a gzip file");
87 		goto gunzip_5;
88 	}
89 
90 	/* skip over gzip header (1f,8b,08... 10 bytes total +
91 	 * possible asciz filename)
92 	 */
93 	strm->next_in = zbuf + 10;
94 	/* skip over asciz filename */
95 	if (zbuf[3] & 0x8) {
96 		while (strm->next_in[0])
97 			strm->next_in++;
98 		strm->next_in++;
99 	}
100 	strm->avail_in = len - (strm->next_in - zbuf);
101 
102 	strm->next_out = out_buf;
103 	strm->avail_out = out_len;
104 
105 	rc = zlib_inflateInit2(strm, -MAX_WBITS);
106 
107 	if (!flush) {
108 		WS(strm)->inflate_state.wsize = 0;
109 		WS(strm)->inflate_state.window = NULL;
110 	}
111 
112 	while (rc == Z_OK) {
113 		if (strm->avail_in == 0) {
114 			/* TODO: handle case where both pos and fill are set */
115 			len = fill(zbuf, INBUF_LEN);
116 			if (len < 0) {
117 				rc = -1;
118 				error("read error");
119 				break;
120 			}
121 			strm->next_in = zbuf;
122 			strm->avail_in = len;
123 		}
124 		rc = zlib_inflate(strm, 0);
125 
126 		/* Write any data generated */
127 		if (flush && strm->next_out > out_buf) {
128 			int l = strm->next_out - out_buf;
129 			if (l != flush(out_buf, l)) {
130 				rc = -1;
131 				error("write error");
132 				break;
133 			}
134 			strm->next_out = out_buf;
135 			strm->avail_out = out_len;
136 		}
137 
138 		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
139 		if (rc == Z_STREAM_END) {
140 			rc = 0;
141 			break;
142 		} else if (rc != Z_OK) {
143 			error("uncompression error");
144 			rc = -1;
145 		}
146 	}
147 
148 	zlib_inflateEnd(strm);
149 	if (pos)
150 		/* add + 8 to skip over trailer */
151 		*pos = strm->next_in - zbuf+8;
152 
153 gunzip_5:
154 	free(strm->workspace);
155 gunzip_nomem4:
156 	free(strm);
157 gunzip_nomem3:
158 	if (!buf)
159 		free(zbuf);
160 gunzip_nomem2:
161 	if (flush)
162 		free(out_buf);
163 gunzip_nomem1:
164 	return rc; /* returns Z_OK (0) if successful */
165 }
166 
167 #define decompress gunzip
168