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>
66 struct fs_ops *exclusive_file_system;
69 * Open file list. The current implementation and assumption is,
70 * we only remove entries from tail and we only add new entries to tail.
71 * This decision is to keep file id management simple - we get list
72 * entries ordered by continiously growing f_id field.
73 * If we do have multiple files open and we do close file not from tail,
74 * this entry will be marked unused. open() will reuse unused entry, or
75 * close will free all unused tail entries.
77 * Only case we expect open file list to grow long, is with zfs pools with
80 file_list_t files = TAILQ_HEAD_INITIALIZER(files);
83 * Walk file list and return pointer to open_file structure.
84 * if fd is < 0, return first unused open_file.
91 TAILQ_FOREACH(f, &files, f_link) {
105 o_gethandle(struct open_file **ptr)
107 struct open_file *f, *last;
109 /* Pick up unused entry */
110 f = fd2open_file(-1);
117 f = calloc(1, sizeof (*f));
121 last = TAILQ_LAST(&files, file_list);
123 f->f_id = last->f_id + 1;
124 TAILQ_INSERT_TAIL(&files, f, f_link);
131 o_rainit(struct open_file *f)
133 f->f_rabuf = malloc(SOPEN_RASIZE);
139 open(const char *fname, int mode)
143 int fd, i, error, besterror;
148 if ((fd = o_gethandle(&f)) == -1) {
153 f->f_flags = mode + 1;
160 if (exclusive_file_system != NULL) {
161 fs = exclusive_file_system;
162 error = (fs->fo_open)(fname, f);
168 error = devopen(f, fname, &file);
170 (((f->f_flags & F_NODEV) == 0) && f->f_dev == NULL))
173 /* see if we opened a raw device; otherwise, 'file' is the file name. */
174 if (file == NULL || *file == '\0') {
181 /* pass file name to the different filesystem open routines */
183 for (i = 0; file_system[i] != NULL; i++) {
185 error = (fs->fo_open)(file, f);
193 if ((f->f_flags & F_NODEV) == 0 && f->f_dev != NULL)
194 f->f_dev->dv_close(f);