1 /* $NetBSD: rawfs.c,v 1.1 1996/05/28 15:23:56 chuck 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 #include <rawfs.h> 44 45 extern int debug; 46 47 #define RAWFS_BSIZE 512 48 49 /* 50 * In-core open file. 51 */ 52 struct file { 53 daddr_t fs_nextblk; /* block number to read next */ 54 int fs_len; /* amount left in f_buf */ 55 char * fs_ptr; /* read pointer into f_buf */ 56 char fs_buf[RAWFS_BSIZE]; 57 }; 58 59 static int 60 rawfs_get_block __P((struct open_file *)); 61 62 int rawfs_open(path, f) 63 char *path; 64 struct open_file *f; 65 { 66 struct file *fs; 67 68 /* 69 * The actual PROM driver has already been opened. 70 * Just allocate the I/O buffer, etc. 71 */ 72 fs = alloc(sizeof(struct file)); 73 fs->fs_nextblk = 0; 74 fs->fs_len = 0; 75 fs->fs_ptr = fs->fs_buf; 76 77 f->f_fsdata = fs; 78 return (0); 79 } 80 81 int rawfs_close(f) 82 struct open_file *f; 83 { 84 struct file *fs; 85 86 fs = (struct file *) f->f_fsdata; 87 f->f_fsdata = (void *)0; 88 89 if (fs != (struct file *)0) 90 free(fs, sizeof(*fs)); 91 92 return (0); 93 } 94 95 int rawfs_read(f, start, size, resid) 96 struct open_file *f; 97 void *start; 98 u_int size; 99 u_int *resid; 100 { 101 struct file *fs = (struct file *)f->f_fsdata; 102 char *addr = start; 103 int error = 0; 104 size_t csize; 105 106 while (size != 0) { 107 108 if (fs->fs_len == 0) 109 if ((error = rawfs_get_block(f)) != 0) 110 break; 111 112 if (fs->fs_len <= 0) 113 break; /* EOF */ 114 115 csize = size; 116 if (csize > fs->fs_len) 117 csize = fs->fs_len; 118 119 bcopy(fs->fs_ptr, addr, csize); 120 fs->fs_ptr += csize; 121 fs->fs_len -= csize; 122 addr += csize; 123 size -= csize; 124 } 125 if (resid) 126 *resid = size; 127 return (error); 128 } 129 130 int rawfs_write(f, start, size, resid) 131 struct open_file *f; 132 void *start; 133 size_t size; 134 size_t *resid; /* out */ 135 { 136 return (EROFS); 137 } 138 139 off_t rawfs_seek(f, offset, where) 140 struct open_file *f; 141 off_t offset; 142 int where; 143 { 144 return (EFTYPE); 145 } 146 147 int rawfs_stat(f, sb) 148 struct open_file *f; 149 struct stat *sb; 150 { 151 return (EFTYPE); 152 } 153 154 155 /* 156 * Read a block from the underlying stream device 157 * (In our case, a tape drive.) 158 */ 159 static int 160 rawfs_get_block(f) 161 struct open_file *f; 162 { 163 struct file *fs; 164 int error, len; 165 166 fs = (struct file *)f->f_fsdata; 167 fs->fs_ptr = fs->fs_buf; 168 169 twiddle(); 170 error = f->f_dev->dv_strategy(f->f_devdata, F_READ, 171 fs->fs_nextblk, RAWFS_BSIZE, fs->fs_buf, &len); 172 173 if (!error) { 174 fs->fs_len = len; 175 fs->fs_nextblk += (RAWFS_BSIZE / DEV_BSIZE); 176 } 177 178 return (error); 179 } 180 181