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 /* $DragonFly: src/lib/libstand/open.c,v 1.2 2003/06/17 04:26:51 dillon Exp $ */
   3 /*      $NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $     */
   4
   5 /*-
   6  * Copyright (c) 1993
   7  *      The Regents of the University of California.  All rights reserved.
   8  *
   9  * This code is derived from software contributed to Berkeley by
  10  * The Mach Operating System project at Carnegie-Mellon University.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  *
  40  *      @(#)open.c      8.1 (Berkeley) 6/11/93
  41  *
  42  *
  43  * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
  44  * All Rights Reserved.
  45  *
  46  * Author: Alessandro Forin
  47  *
  48  * Permission to use, copy, modify and distribute this software and its
  49  * documentation is hereby granted, provided that both the copyright
  50  * notice and this permission notice appear in all copies of the
  51  * software, derivative works or modified versions, and any portions
  52  * thereof, and that both notices appear in supporting documentation.
  53  *
  54  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  55  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  56  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  57  *
  58  * Carnegie Mellon requests users of this software to return to
  59  *
  60  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  61  *  School of Computer Science
  62  *  Carnegie Mellon University
  63  *  Pittsburgh PA 15213-3890
  64  *
  65  * any improvements or extensions that they make and grant Carnegie the
  66  * rights to redistribute these changes.
  67  */
  68
  69 #include "stand.h"
  70
  71 struct open_file files[SOPEN_MAX];
  72
  73 static int
  74 o_gethandle(void)
  75 {
  76     int         fd;
  77
  78     for (fd = 0; fd < SOPEN_MAX; fd++)
  79         if (files[fd].f_flags == 0)
  80             return(fd);
  81     return(-1);
  82 }
  83
  84 static void
  85 o_rainit(struct open_file *f)
  86 {
  87     f->f_rabuf = malloc(SOPEN_RASIZE);
  88     f->f_ralen = 0;
  89     f->f_raoffset = 0;
  90 }
  91
  92 int
  93 open(const char *fname, int mode)
  94 {
  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 = NULL;
 107     f->f_ops = NULL;
 108     f->f_offset = 0;
 109     f->f_devdata = NULL;
 110     f->f_fsdata = NULL;
 111     file = NULL;
 112     error = devopen(f, fname, &file);
 113     if (error ||
 114         (((f->f_flags & F_NODEV) == 0) && f->f_dev == NULL))
 115         goto err;
 116
 117     /* see if we opened a raw device; otherwise, 'file' is the file name. */
 118     if (file == NULL || *file == '\0') {
 119         f->f_flags |= F_RAW;
 120         return (fd);
 121     }
 122
 123     /* pass file name to the different filesystem open routines */
 124     besterror = ENOENT;
 125     for (i = 0; file_system[i] != NULL; i++) {
 126         error = ((*file_system[i]).fo_open)(file, f);
 127         if (error == 0) {
 128             f->f_ops = file_system[i];
 129             o_rainit(f);
 130             return (fd);
 131         }
 132         if (error != EINVAL)
 133             besterror = error;
 134     }
 135     error = besterror;
 136
 137     if ((f->f_flags & F_NODEV) == 0)
 138         f->f_dev->dv_close(f);
 139     if (error)
 140         devclose(f);
 141
 142  err:
 143     f->f_flags = 0;
 144     errno = error;
 145     return (-1);
 146 }