xref: /openbmc/linux/lib/decompress_inflate.c (revision 842ed298)
1 // SPDX-License-Identifier: GPL-2.0
2 #ifdef STATIC
3 #define PREBOOT
4 /* Pre-boot environment: included */
5 
6 /* prevent inclusion of _LINUX_KERNEL_H in pre-boot environment: lots
7  * errors about console_printk etc... on ARM */
8 #define _LINUX_KERNEL_H
9 
10 #include "zlib_inflate/inftrees.c"
11 #include "zlib_inflate/inffast.c"
12 #include "zlib_inflate/inflate.c"
13 #ifdef CONFIG_ZLIB_DFLTCC
14 #include "zlib_dfltcc/dfltcc.c"
15 #include "zlib_dfltcc/dfltcc_inflate.c"
16 #endif
17 
18 #else /* STATIC */
19 /* initramfs et al: linked */
20 
21 #include <linux/zutil.h>
22 
23 #include "zlib_inflate/inftrees.h"
24 #include "zlib_inflate/inffast.h"
25 #include "zlib_inflate/inflate.h"
26 
27 #include "zlib_inflate/infutil.h"
28 #include <linux/decompress/inflate.h>
29 
30 #endif /* STATIC */
31 
32 #include <linux/decompress/mm.h>
33 
34 #define GZIP_IOBUF_SIZE (16*1024)
35 
36 static long INIT nofill(void *buffer, unsigned long len)
37 {
38 	return -1;
39 }
40 
41 /* Included from initramfs et al code */
42 STATIC int INIT __gunzip(unsigned char *buf, long len,
43 		       long (*fill)(void*, unsigned long),
44 		       long (*flush)(void*, unsigned long),
45 		       unsigned char *out_buf, long out_len,
46 		       long *pos,
47 		       void(*error)(char *x)) {
48 	u8 *zbuf;
49 	struct z_stream_s *strm;
50 	int rc;
51 
52 	rc = -1;
53 	if (flush) {
54 		out_len = 0x8000; /* 32 K */
55 		out_buf = malloc(out_len);
56 	} else {
57 		if (!out_len)
58 			out_len = ((size_t)~0) - (size_t)out_buf; /* no limit */
59 	}
60 	if (!out_buf) {
61 		error("Out of memory while allocating output buffer");
62 		goto gunzip_nomem1;
63 	}
64 
65 	if (buf)
66 		zbuf = buf;
67 	else {
68 		zbuf = malloc(GZIP_IOBUF_SIZE);
69 		len = 0;
70 	}
71 	if (!zbuf) {
72 		error("Out of memory while allocating input buffer");
73 		goto gunzip_nomem2;
74 	}
75 
76 	strm = malloc(sizeof(*strm));
77 	if (strm == NULL) {
78 		error("Out of memory while allocating z_stream");
79 		goto gunzip_nomem3;
80 	}
81 
82 	strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
83 #ifdef CONFIG_ZLIB_DFLTCC
84 	/* Always allocate the full workspace for DFLTCC */
85 				 zlib_inflate_workspacesize());
86 #else
87 				 sizeof(struct inflate_state));
88 #endif
89 	if (strm->workspace == NULL) {
90 		error("Out of memory while allocating workspace");
91 		goto gunzip_nomem4;
92 	}
93 
94 	if (!fill)
95 		fill = nofill;
96 
97 	if (len == 0)
98 		len = fill(zbuf, GZIP_IOBUF_SIZE);
99 
100 	/* verify the gzip header */
101 	if (len < 10 ||
102 	   zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
103 		if (pos)
104 			*pos = 0;
105 		error("Not a gzip file");
106 		goto gunzip_5;
107 	}
108 
109 	/* skip over gzip header (1f,8b,08... 10 bytes total +
110 	 * possible asciz filename)
111 	 */
112 	strm->next_in = zbuf + 10;
113 	strm->avail_in = len - 10;
114 	/* skip over asciz filename */
115 	if (zbuf[3] & 0x8) {
116 		do {
117 			/*
118 			 * If the filename doesn't fit into the buffer,
119 			 * the file is very probably corrupt. Don't try
120 			 * to read more data.
121 			 */
122 			if (strm->avail_in == 0) {
123 				error("header error");
124 				goto gunzip_5;
125 			}
126 			--strm->avail_in;
127 		} while (*strm->next_in++);
128 	}
129 
130 	strm->next_out = out_buf;
131 	strm->avail_out = out_len;
132 
133 	rc = zlib_inflateInit2(strm, -MAX_WBITS);
134 
135 #ifdef CONFIG_ZLIB_DFLTCC
136 	/* Always keep the window for DFLTCC */
137 #else
138 	if (!flush) {
139 		WS(strm)->inflate_state.wsize = 0;
140 		WS(strm)->inflate_state.window = NULL;
141 	}
142 #endif
143 
144 	while (rc == Z_OK) {
145 		if (strm->avail_in == 0) {
146 			/* TODO: handle case where both pos and fill are set */
147 			len = fill(zbuf, GZIP_IOBUF_SIZE);
148 			if (len < 0) {
149 				rc = -1;
150 				error("read error");
151 				break;
152 			}
153 			strm->next_in = zbuf;
154 			strm->avail_in = len;
155 		}
156 		rc = zlib_inflate(strm, 0);
157 
158 		/* Write any data generated */
159 		if (flush && strm->next_out > out_buf) {
160 			long l = strm->next_out - out_buf;
161 			if (l != flush(out_buf, l)) {
162 				rc = -1;
163 				error("write error");
164 				break;
165 			}
166 			strm->next_out = out_buf;
167 			strm->avail_out = out_len;
168 		}
169 
170 		/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
171 		if (rc == Z_STREAM_END) {
172 			rc = 0;
173 			break;
174 		} else if (rc != Z_OK) {
175 			error("uncompression error");
176 			rc = -1;
177 		}
178 	}
179 
180 	zlib_inflateEnd(strm);
181 	if (pos)
182 		/* add + 8 to skip over trailer */
183 		*pos = strm->next_in - zbuf+8;
184 
185 gunzip_5:
186 	free(strm->workspace);
187 gunzip_nomem4:
188 	free(strm);
189 gunzip_nomem3:
190 	if (!buf)
191 		free(zbuf);
192 gunzip_nomem2:
193 	if (flush)
194 		free(out_buf);
195 gunzip_nomem1:
196 	return rc; /* returns Z_OK (0) if successful */
197 }
198 
199 #ifndef PREBOOT
200 STATIC int INIT gunzip(unsigned char *buf, long len,
201 		       long (*fill)(void*, unsigned long),
202 		       long (*flush)(void*, unsigned long),
203 		       unsigned char *out_buf,
204 		       long *pos,
205 		       void (*error)(char *x))
206 {
207 	return __gunzip(buf, len, fill, flush, out_buf, 0, pos, error);
208 }
209 #else
210 STATIC int INIT __decompress(unsigned char *buf, long len,
211 			   long (*fill)(void*, unsigned long),
212 			   long (*flush)(void*, unsigned long),
213 			   unsigned char *out_buf, long out_len,
214 			   long *pos,
215 			   void (*error)(char *x))
216 {
217 	return __gunzip(buf, len, fill, flush, out_buf, out_len, pos, error);
218 }
219 #endif
220