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 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 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 } 130 131 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 } 139 140 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
