1 /* $NetBSD: open.c,v 1.16 1997/01/28 09:41:03 pk Exp $ */
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34 * @(#)open.c 8.1 (Berkeley) 6/11/93
37 * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
38 * All Rights Reserved.
40 * Author: Alessandro Forin
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54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
55 * School of Computer Science
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59 * any improvements or extensions that they make and grant Carnegie the
60 * rights to redistribute these changes.
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
68 struct fs_ops *exclusive_file_system;
71 * Open file list. The current implementation and assumption is,
72 * we only remove entries from tail and we only add new entries to tail.
73 * This decision is to keep file id management simple - we get list
74 * entries ordered by continiously growing f_id field.
75 * If we do have multiple files open and we do close file not from tail,
76 * this entry will be marked unused. open() will reuse unused entry, or
77 * close will free all unused tail entries.
79 * Only case we expect open file list to grow long, is with zfs pools with
82 file_list_t files = TAILQ_HEAD_INITIALIZER(files);
85 * Walk file list and return pointer to open_file structure.
86 * if fd is < 0, return first unused open_file.
93 TAILQ_FOREACH(f, &files, f_link) {
107 o_gethandle(struct open_file **ptr)
109 struct open_file *f, *last;
111 /* Pick up unused entry */
112 f = fd2open_file(-1);
119 f = calloc(1, sizeof (*f));
123 last = TAILQ_LAST(&files, file_list);
125 f->f_id = last->f_id + 1;
126 TAILQ_INSERT_TAIL(&files, f, f_link);
133 o_rainit(struct open_file *f)
135 f->f_rabuf = malloc(SOPEN_RASIZE);
141 open(const char *fname, int mode)
145 int fd, i, error, besterror;
150 if ((fd = o_gethandle(&f)) == -1) {
155 f->f_flags = mode + 1;
162 if (exclusive_file_system != NULL) {
163 fs = exclusive_file_system;
164 error = (fs->fo_open)(fname, f);
170 error = devopen(f, fname, &file);
172 (((f->f_flags & F_NODEV) == 0) && f->f_dev == NULL))
175 /* see if we opened a raw device; otherwise, 'file' is the file name. */
176 if (file == NULL || *file == '\0') {
183 /* pass file name to the different filesystem open routines */
185 for (i = 0; file_system[i] != NULL; i++) {
187 error = (fs->fo_open)(file, f);
195 if ((f->f_flags & F_NODEV) == 0 && f->f_dev != NULL)
196 f->f_dev->dv_close(f);