1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2003-2008 H. Peter Anvin - All Rights Reserved
4 *
5 * Permission is hereby granted, free of charge, to any person
6 * obtaining a copy of this software and associated documentation
7 * files (the "Software"), to deal in the Software without
8 * restriction, including without limitation the rights to use,
9 * copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom
11 * the Software is furnished to do so, subject to the following
12 * conditions:
13 *
14 * The above copyright notice and this permission notice shall
15 * be included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 * OTHER DEALINGS IN THE SOFTWARE.
25 *
26 * ----------------------------------------------------------------------- */
27
28 #include <errno.h>
29 #include <string.h>
30 #include <unistd.h>
31 #include <fcntl.h>
32 #include <stdlib.h>
33 #include <syslinux/zio.h>
34
35 #include "file.h"
36 #include "zlib.h"
37
38 /*
39 * zopen.c
40 *
41 * Open an ordinary file, possibly compressed; if so, insert
42 * an appropriate decompressor.
43 */
44
45 int __file_get_block(struct file_info *fp);
46 int __file_close(struct file_info *fp);
47
48 static ssize_t gzip_file_read(struct file_info *, void *, size_t);
49 static int gzip_file_close(struct file_info *);
50
51 static const struct input_dev gzip_file_dev = {
52 .dev_magic = __DEV_MAGIC,
53 .flags = __DEV_FILE | __DEV_INPUT,
54 .fileflags = O_RDONLY,
55 .read = gzip_file_read,
56 .close = gzip_file_close,
57 .open = NULL,
58 };
59
gzip_file_init(struct file_info * fp)60 static int gzip_file_init(struct file_info *fp)
61 {
62 z_streamp zs = calloc(1, sizeof(z_stream));
63
64 if (!zs)
65 return -1;
66
67 fp->i.pvt = zs;
68
69 zs->next_in = (void *)fp->i.datap;
70 zs->avail_in = fp->i.nbytes;
71
72 if (inflateInit2(zs, 15 + 32) != Z_OK) {
73 errno = EIO;
74 return -1;
75 }
76
77 fp->iop = &gzip_file_dev;
78 fp->i.fd.size = -1; /* Unknown */
79
80 return 0;
81 }
82
gzip_file_read(struct file_info * fp,void * ptr,size_t n)83 static ssize_t gzip_file_read(struct file_info *fp, void *ptr, size_t n)
84 {
85 z_streamp zs = fp->i.pvt;
86 int rv;
87 ssize_t bytes;
88 ssize_t nout = 0;
89 unsigned char *p = ptr;
90
91 while (n) {
92 zs->next_out = p;
93 zs->avail_out = n;
94
95 if (!zs->avail_in && fp->i.fd.handle) {
96 if (__file_get_block(fp))
97 return nout ? nout : -1;
98
99 zs->next_in = (void *)fp->i.datap;
100 zs->avail_in = fp->i.nbytes;
101 }
102
103 rv = inflate(zs, Z_SYNC_FLUSH);
104
105 bytes = n - zs->avail_out;
106 nout += bytes;
107 p += bytes;
108 n -= bytes;
109
110 switch (rv) {
111 case Z_DATA_ERROR:
112 case Z_NEED_DICT:
113 case Z_BUF_ERROR:
114 case Z_STREAM_ERROR:
115 default:
116 errno = EIO;
117 return nout ? nout : -1;
118 case Z_MEM_ERROR:
119 errno = ENOMEM;
120 return nout ? nout : -1;
121 case Z_STREAM_END:
122 return nout;
123 case Z_OK:
124 break;
125 }
126 }
127
128 return nout;
129 }
130
gzip_file_close(struct file_info * fp)131 static int gzip_file_close(struct file_info *fp)
132 {
133 z_streamp zs = fp->i.pvt;
134
135 inflateEnd(zs);
136 free(zs);
137 return __file_close(fp);
138 }
139
zopen(const char * pathname,int flags,...)140 int zopen(const char *pathname, int flags, ...)
141 {
142 int fd, rv;
143 struct file_info *fp;
144
145 /* We don't actually give a hoot about the creation bits... */
146 fd = open(pathname, flags, 0);
147
148 if (fd < 0)
149 return -1;
150
151 fp = &__file_info[fd];
152
153 /* Need to get the first block into the buffer, but not consumed */
154 if (__file_get_block(fp))
155 goto err;
156
157 if (fp->i.nbytes >= 14 &&
158 (uint8_t) fp->i.buf[0] == 037 &&
159 (uint8_t) fp->i.buf[1] == 0213 && /* gzip */
160 fp->i.buf[2] == 8) /* deflate */
161 rv = gzip_file_init(fp);
162 else
163 rv = 0; /* Plain file */
164
165 if (!rv)
166 return fd;
167
168 err:
169 close(fd);
170 return -1;
171 }
172