rawfs.c revision 1.1.24.2
1 /* $NetBSD: rawfs.c,v 1.1.24.2 2004/09/18 14:41:57 skrll Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Gordon W. Ross 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 4. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by Gordon W. Ross 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Raw file system - for stream devices like tapes. 35 * No random access, only sequential read allowed. 36 * This exists only to allow upper level code to be 37 * shielded from the fact that the device must be 38 * read only with whole block position and size. 39 */ 40 41 #include <sys/param.h> 42 #include <stand.h> 43 44 #include "rawfs.h" 45 46 extern int debug; 47 48 /* Our devices are generally willing to do 8K transfers. */ 49 #define RAWFS_BSIZE 0x2000 50 51 /* 52 * In-core open file. 53 */ 54 struct file { 55 daddr_t fs_nextblk; /* block number to read next */ 56 off_t fs_off; /* seek offset in file */ 57 int fs_len; /* amount left in f_buf */ 58 char * fs_ptr; /* read pointer into f_buf */ 59 char fs_buf[RAWFS_BSIZE]; 60 }; 61 62 static int rawfs_get_block __P((struct open_file *)); 63 64 int 65 rawfs_open(path, f) 66 const char *path; 67 struct open_file *f; 68 { 69 struct file *fs; 70 71 /* 72 * The actual PROM driver has already been opened. 73 * Just allocate the I/O buffer, etc. 74 */ 75 fs = alloc(sizeof(struct file)); 76 fs->fs_nextblk = 0; 77 fs->fs_off = 0; 78 fs->fs_len = 0; 79 fs->fs_ptr = fs->fs_buf; 80 81 #ifdef DEBUG_RAWFS 82 printf("rawfs_open: fs=0x%x\n", fs); 83 #endif 84 85 f->f_fsdata = fs; 86 return (0); 87 } 88 89 int 90 rawfs_close(f) 91 struct open_file *f; 92 { 93 struct file *fs; 94 95 fs = (struct file *) f->f_fsdata; 96 f->f_fsdata = NULL; 97 98 #ifdef DEBUG_RAWFS 99 if (debug) { 100 printf("rawfs_close: breakpoint...", fs->fs_buf); 101 __asm (" trap #0"); 102 } 103 #endif 104 105 if (fs != NULL) 106 free(fs, sizeof(*fs)); 107 108 return (0); 109 } 110 111 int 112 rawfs_read(f, start, size, resid) 113 struct open_file *f; 114 void *start; 115 u_int size; 116 u_int *resid; 117 { 118 struct file *fs = (struct file *)f->f_fsdata; 119 char *addr = start; 120 int error = 0; 121 size_t csize; 122 123 while (size != 0) { 124 125 if (fs->fs_len == 0) 126 if ((error = rawfs_get_block(f)) != 0) 127 break; 128 129 if (fs->fs_len <= 0) 130 break; /* EOF */ 131 132 csize = size; 133 if (csize > fs->fs_len) 134 csize = fs->fs_len; 135 136 bcopy(fs->fs_ptr, addr, csize); 137 fs->fs_off += csize; 138 fs->fs_ptr += csize; 139 fs->fs_len -= csize; 140 addr += csize; 141 size -= csize; 142 } 143 if (resid) 144 *resid = size; 145 return (error); 146 } 147 148 int 149 rawfs_write(f, start, size, resid) 150 struct open_file *f; 151 void *start; 152 size_t size; 153 size_t *resid; /* out */ 154 { 155 #ifdef DEBUG_RAWFS 156 panic("rawfs_write"); 157 #endif 158 return (EROFS); 159 } 160 161 off_t 162 rawfs_seek(f, offset, where) 163 struct open_file *f; 164 off_t offset; 165 int where; 166 { 167 struct file *fs = (struct file *)f->f_fsdata; 168 off_t csize; 169 170 switch (where) { 171 case SEEK_SET: 172 offset -= fs->fs_off; 173 /* FALLTHROUGH */ 174 case SEEK_CUR: 175 if (offset >= 0) 176 break; 177 /* FALLTHROUGH */ 178 case SEEK_END: 179 default: 180 return (-1); 181 } 182 183 while (offset != 0) { 184 185 if (fs->fs_len == 0) 186 if (rawfs_get_block(f) != 0) 187 return (-1); 188 189 if (fs->fs_len <= 0) 190 break; /* EOF */ 191 192 csize = offset; 193 if (csize > fs->fs_len) 194 csize = fs->fs_len; 195 196 fs->fs_off += csize; 197 fs->fs_ptr += csize; 198 fs->fs_len -= csize; 199 offset -= csize; 200 } 201 return (fs->fs_off); 202 } 203 204 int 205 rawfs_stat(f, sb) 206 struct open_file *f; 207 struct stat *sb; 208 { 209 #ifdef DEBUG_RAWFS 210 panic("rawfs_stat"); 211 #endif 212 return (EFTYPE); 213 } 214 215 216 /* 217 * Read a block from the underlying stream device 218 * (In our case, a tape drive.) 219 */ 220 static int 221 rawfs_get_block(f) 222 struct open_file *f; 223 { 224 struct file *fs; 225 int error, len; 226 227 fs = (struct file *)f->f_fsdata; 228 fs->fs_ptr = fs->fs_buf; 229 230 twiddle(); 231 error = f->f_dev->dv_strategy(f->f_devdata, F_READ, 232 fs->fs_nextblk, RAWFS_BSIZE, fs->fs_buf, &len); 233 234 if (!error) { 235 fs->fs_len = len; 236 fs->fs_nextblk += (RAWFS_BSIZE / DEV_BSIZE); 237 } 238 239 return (error); 240 } 241 242
Indexes created Wed Oct 01 15:09:59 GMT 2025