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/* $NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $ */
/*
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)open.c 8.1 (Berkeley) 6/11/93
*
*
* Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
* All Rights Reserved.
*
* Author: Alessandro Forin
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/cdefs.h>
#include "stand.h"
struct fs_ops *exclusive_file_system;
/*
* Open file list. The current implementation and assumption is,
* we only remove entries from tail and we only add new entries to tail.
* This decision is to keep file id management simple - we get list
* entries ordered by continiously growing f_id field.
* If we do have multiple files open and we do close file not from tail,
* this entry will be marked unused. open() will reuse unused entry, or
* close will free all unused tail entries.
*
* Only case we expect open file list to grow long, is with zfs pools with
* many disks.
*/
file_list_t files = TAILQ_HEAD_INITIALIZER(files);
/*
* Walk file list and return pointer to open_file structure.
* if fd is < 0, return first unused open_file.
*/
struct open_file *
fd2open_file(int fd)
{
struct open_file *f;
TAILQ_FOREACH(f, &files, f_link) {
if (fd >= 0) {
if (f->f_id == fd)
break;
continue;
}
if (f->f_flags == 0)
break;
}
return (f);
}
static int
o_gethandle(struct open_file **ptr)
{
struct open_file *f, *last;
/* Pick up unused entry */
f = fd2open_file(-1);
if (f != NULL) {
*ptr = f;
return (f->f_id);
}
/* Add new entry */
f = calloc(1, sizeof (*f));
if (f == NULL)
return (-1);
last = TAILQ_LAST(&files, file_list);
if (last != NULL)
f->f_id = last->f_id + 1;
TAILQ_INSERT_TAIL(&files, f, f_link);
*ptr = f;
return (f->f_id);
}
static void
o_rainit(struct open_file *f)
{
f->f_rabuf = malloc(SOPEN_RASIZE);
f->f_ralen = 0;
f->f_raoffset = 0;
}
int
open(const char *fname, int mode)
{
struct fs_ops *fs;
struct open_file *f;
int fd, i, error, besterror;
const char *file;
if ((fd = o_gethandle(&f)) == -1) {
errno = EMFILE;
return (-1);
}
f->f_flags = mode + 1;
f->f_dev = NULL;
f->f_ops = NULL;
f->f_offset = 0;
f->f_devdata = NULL;
file = NULL;
if (exclusive_file_system != NULL) {
fs = exclusive_file_system;
error = (fs->fo_open)(fname, f);
if (error == 0)
goto ok;
goto err;
}
error = devopen(f, fname, &file);
if (error ||
(((f->f_flags & F_NODEV) == 0) && f->f_dev == NULL))
goto err;
/* see if we opened a raw device; otherwise, 'file' is the file name. */
if (file == NULL || *file == '\0') {
f->f_flags |= F_RAW;
f->f_rabuf = NULL;
return (fd);
}
/* pass file name to the different filesystem open routines */
besterror = ENOENT;
for (i = 0; file_system[i] != NULL; i++) {
fs = file_system[i];
error = (fs->fo_open)(file, f);
if (error == 0)
goto ok;
if (error != EINVAL)
besterror = error;
}
error = besterror;
if ((f->f_flags & F_NODEV) == 0 && f->f_dev != NULL)
f->f_dev->dv_close(f);
if (error)
devclose(f);
err:
f->f_flags = 0;
errno = error;
return (-1);
ok:
f->f_ops = fs;
o_rainit(f);
return (fd);
}
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