1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * %sccs.include.redist.c% 9 * 10 * @(#)open.c 8.1 (Berkeley) 06/11/93 11 * 12 * 13 * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University 14 * All Rights Reserved. 15 * 16 * Author: Alessandro Forin 17 * 18 * Permission to use, copy, modify and distribute this software and its 19 * documentation is hereby granted, provided that both the copyright 20 * notice and this permission notice appear in all copies of the 21 * software, derivative works or modified versions, and any portions 22 * thereof, and that both notices appear in supporting documentation. 23 * 24 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 25 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 26 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 27 * 28 * Carnegie Mellon requests users of this software to return to 29 * 30 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 31 * School of Computer Science 32 * Carnegie Mellon University 33 * Pittsburgh PA 15213-3890 34 * 35 * any improvements or extensions that they make and grant Carnegie the 36 * rights to redistribute these changes. 37 */ 38 39 #include <stand/stand.h> 40 #include <stand/ufs.h> 41 42 /* 43 * File primitives proper 44 */ 45 46 struct fs_ops file_system[] = { 47 { ufs_open, ufs_close, ufs_read, ufs_write, ufs_seek, ufs_stat } 48 }; 49 #define NFSYS (sizeof(file_system) / sizeof(struct fs_ops)) 50 51 struct open_file files[SOPEN_MAX]; 52 53 open(fname, mode) 54 char *fname; 55 int mode; 56 { 57 register struct open_file *f; 58 register int fd, i, error; 59 char *file; 60 61 /* find a free file descriptor */ 62 for (fd = 0, f = files; fd < SOPEN_MAX; fd++, f++) 63 if (f->f_flags == 0) 64 goto fnd; 65 return (-1); 66 fnd: 67 /* 68 * Try to open the device. 69 * Convert open mode (0,1,2) to F_READ, F_WRITE. 70 */ 71 f->f_flags = mode + 1; 72 f->f_dev = (struct devsw *)0; 73 file = (char *)0; 74 error = devopen(f, fname, &file); 75 if (error || f->f_dev == (struct devsw *)0) 76 goto err; 77 78 /* see if we opened a raw device; otherwise, 'file' is the file name. */ 79 if (file == (char *)0) { 80 f->f_flags |= F_RAW; 81 return (0); 82 } 83 84 /* pass file name to the different filesystem open routines */ 85 for (i = 0; i < NFSYS; i++) { 86 /* convert mode (0,1,2) to FREAD, FWRITE. */ 87 error = (file_system[i].open)(file, f); 88 if (error == 0) { 89 f->f_ops = &file_system[i]; 90 return (fd); 91 } 92 } 93 if (!error) 94 error = ENOENT; 95 96 err: 97 errno = error; 98 return (-1); 99 } 100