lib/libstand/open.c

   1 /* $FreeBSD: src/lib/libstand/open.c,v 1.2.6.1 2000/09/10 01:32:06 ps Exp $ */
   2 /*      $NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $     */
   3
   4 /*-
   5  * Copyright (c) 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * The Mach Operating System project at Carnegie-Mellon University.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  *      @(#)open.c      8.1 (Berkeley) 6/11/93
  36  *
  37  *
  38  * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
  39  * All Rights Reserved.
  40  *
  41  * Author: Alessandro Forin
  42  *
  43  * Permission to use, copy, modify and distribute this software and its
  44  * documentation is hereby granted, provided that both the copyright
  45  * notice and this permission notice appear in all copies of the
  46  * software, derivative works or modified versions, and any portions
  47  * thereof, and that both notices appear in supporting documentation.
  48  *
  49  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  50  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  51  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  52  *
  53  * Carnegie Mellon requests users of this software to return to
  54  *
  55  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  56  *  School of Computer Science
  57  *  Carnegie Mellon University
  58  *  Pittsburgh PA 15213-3890
  59  *
  60  * any improvements or extensions that they make and grant Carnegie the
  61  * rights to redistribute these changes.
  62  */
  63
  64 #include "stand.h"
  65
  66 struct open_file files[SOPEN_MAX];
  67
  68 static int
  69 o_gethandle(void)
  70 {
  71     int         fd;
  72
  73     for (fd = 0; fd < SOPEN_MAX; fd++)
  74         if (files[fd].f_flags == 0)
  75             return(fd);
  76     return(-1);
  77 }
  78
  79 static void
  80 o_rainit(struct open_file *f)
  81 {
  82     f->f_rabuf = malloc(SOPEN_RASIZE);
  83     f->f_ralen = 0;
  84     f->f_raoffset = 0;
  85 }
  86
  87 int
  88 open(const char *fname, int mode)
  89 {
  90     struct open_file    *f;
  91     int                 fd, i, error, besterror;
  92     const char          *file;
  93
  94     if ((fd = o_gethandle()) == -1) {
  95         errno = EMFILE;
  96         return(-1);
  97     }
  98
  99     f = &files[fd];
 100     f->f_flags = mode + 1;
 101     f->f_dev = NULL;
 102     f->f_ops = NULL;
 103     f->f_offset = 0;
 104     f->f_devdata = NULL;
 105     f->f_fsdata = NULL;
 106     file = NULL;
 107     error = devopen(f, fname, &file);
 108     if (error || f->f_dev == NULL)
 109         goto err;
 110
 111     /* see if we opened a raw device; otherwise, 'file' is the file name. */
 112     if (file == NULL || *file == '\0') {
 113         f->f_flags |= F_RAW;
 114         return (fd);
 115     }
 116
 117     /* pass file name to the different filesystem open routines */
 118     besterror = ENOENT;
 119     for (i = 0; file_system[i] != NULL; i++) {
 120         error = ((*file_system[i]).fo_open)(file, f);
 121         if (error == 0) {
 122             f->f_ops = file_system[i];
 123             o_rainit(f);
 124             return (fd);
 125         }
 126         if (error != EINVAL)
 127             besterror = error;
 128     }
 129     error = besterror;
 130
 131     if (f->f_dev)
 132         f->f_dev->dv_close(f);
 133     if (error)
 134         devclose(f);
 135
 136 err:
 137     f->f_flags = 0;
 138     errno = error;
 139     return (-1);
 140 }