/* $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. * * * 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 "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; bool is_dir; size_t n; const char *file; TSENTER(); 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 || (exclusive_file_system->fs_flags & FS_OPS_NO_DEVOPEN) == 0) { 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; TSEXIT(); return (fd); } } else file = fname; if (exclusive_file_system != NULL) { /* loader is forcing the filesystem to be used */ fs = exclusive_file_system; error = (fs->fo_open)(file, f); if (error == 0) goto ok; goto err; } /* pass file name to the different filesystem open routines */ besterror = ENOENT; n = strlen(file); is_dir = (n > 0 && file[n - 1] == '/'); for (i = 0; file_system[i] != NULL; i++) { fs = file_system[i]; if (is_dir && is_tftp()) { error = EOPNOTSUPP; goto err; } 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; TSEXIT(); return (-1); ok: f->f_ops = fs; o_rainit(f); TSEXIT(); return (fd); }
