usr/src/boot/lib/libstand/open.c

   1 /*      $NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $     */
   2
   3 /*-
   4  * Copyright (c) 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * The Mach Operating System project at Carnegie-Mellon University.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)open.c      8.1 (Berkeley) 6/11/93
  35  *
  36  *
  37  * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
  38  * All Rights Reserved.
  39  *
  40  * Author: Alessandro Forin
  41  *
  42  * Permission to use, copy, modify and distribute this software and its
  43  * documentation is hereby granted, provided that both the copyright
  44  * notice and this permission notice appear in all copies of the
  45  * software, derivative works or modified versions, and any portions
  46  * thereof, and that both notices appear in supporting documentation.
  47  *
  48  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  49  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  50  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  51  *
  52  * Carnegie Mellon requests users of this software to return to
  53  *
  54  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  55  *  School of Computer Science
  56  *  Carnegie Mellon University
  57  *  Pittsburgh PA 15213-3890
  58  *
  59  * any improvements or extensions that they make and grant Carnegie the
  60  * rights to redistribute these changes.
  61  */
  62
  63 #include <sys/cdefs.h>
  64 __FBSDID("$FreeBSD$");
  65
  66 #include "stand.h"
  67
  68 struct fs_ops *exclusive_file_system;
  69
  70 struct open_file files[SOPEN_MAX];
  71
  72 static int
  73 o_gethandle(void)
  74 {
  75     int         fd;
  76
  77     for (fd = 0; fd < SOPEN_MAX; fd++)
  78         if (files[fd].f_flags == 0)
  79             return(fd);
  80     return(-1);
  81 }
  82
  83 static void
  84 o_rainit(struct open_file *f)
  85 {
  86     f->f_rabuf = malloc(SOPEN_RASIZE);
  87     f->f_ralen = 0;
  88     f->f_raoffset = 0;
  89 }
  90
  91 int
  92 open(const char *fname, int mode)
  93 {
  94     struct fs_ops       *fs;
  95     struct open_file    *f;
  96     int                 fd, i, error, besterror;
  97     const char          *file;
  98
  99     if ((fd = o_gethandle()) == -1) {
 100         errno = EMFILE;
 101         return(-1);
 102     }
 103
 104     f = &files[fd];
 105     f->f_flags = mode + 1;
 106     f->f_dev = (struct devsw *)0;
 107     f->f_ops = (struct fs_ops *)0;
 108     f->f_offset = 0;
 109     f->f_devdata = NULL;
 110     file = (char *)0;
 111
 112     if (exclusive_file_system != NULL) {
 113         fs = exclusive_file_system;
 114         error = (fs->fo_open)(fname, f);
 115         if (error == 0)
 116             goto ok;
 117         goto fail;
 118     }
 119
 120     error = devopen(f, fname, &file);
 121     if (error ||
 122         (((f->f_flags & F_NODEV) == 0) && f->f_dev == (struct devsw *)0))
 123         goto err;
 124
 125     /* see if we opened a raw device; otherwise, 'file' is the file name. */
 126     if (file == (char *)0 || *file == '\0') {
 127         f->f_flags |= F_RAW;
 128         f->f_rabuf = NULL;
 129         return (fd);
 130     }
 131
 132     /* pass file name to the different filesystem open routines */
 133     besterror = ENOENT;
 134     for (i = 0; file_system[i] != NULL; i++) {
 135         fs = file_system[i];
 136         error = (fs->fo_open)(file, f);
 137         if (error == 0)
 138             goto ok;
 139         if (error != EINVAL)
 140             besterror = error;
 141     }
 142     error = besterror;
 143
 144  fail:
 145     if ((f->f_flags & F_NODEV) == 0 && f->f_dev != NULL)
 146         f->f_dev->dv_close(f);
 147     if (error)
 148         devclose(f);
 149
 150  err:
 151     f->f_flags = 0;
 152     errno = error;
 153     return (-1);
 154
 155  ok:
 156     f->f_ops = fs;
 157     o_rainit(f);
 158     return (fd);
 159 }