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Diffstat (limited to 'sys/sys/filedesc.h')
| -rw-r--r-- | sys/sys/filedesc.h | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/sys/sys/filedesc.h b/sys/sys/filedesc.h new file mode 100644 index 0000000..ef784f7 --- /dev/null +++ b/sys/sys/filedesc.h @@ -0,0 +1,157 @@ +/* $OpenBSD: filedesc.h,v 1.44 2020/01/30 15:33:04 visa Exp $ */ +/* $NetBSD: filedesc.h,v 1.14 1996/04/09 20:55:28 cgd Exp $ */ + +/* + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * 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. + * + * @(#)filedesc.h 8.1 (Berkeley) 6/2/93 + */ + +#include <sys/mutex.h> +#include <sys/rwlock.h> +/* + * This structure is used for the management of descriptors. It may be + * shared by multiple processes. + * + * A process is initially started out with NDFILE descriptors stored within + * this structure, selected to be enough for typical applications based on + * the historical limit of 20 open files (and the usage of descriptors by + * shells). If these descriptors are exhausted, a larger descriptor table + * may be allocated, up to a process' resource limit; the internal arrays + * are then unused. The initial expansion is set to NDEXTENT; each time + * it runs out, it is doubled until the resource limit is reached. NDEXTENT + * should be selected to be the biggest multiple of OFILESIZE (see below) + * that will fit in a power-of-two sized piece of memory. + */ +#define NDFILE 20 +#define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */ +#define NDENTRIES 32 /* 32 fds per entry */ +#define NDENTRYMASK (NDENTRIES - 1) +#define NDENTRYSHIFT 5 /* bits per entry */ +#define NDREDUCE(x) (((x) + NDENTRIES - 1) >> NDENTRYSHIFT) +#define NDHISLOTS(x) (NDREDUCE(NDREDUCE(x))) +#define NDLOSLOTS(x) (NDHISLOTS(x) << NDENTRYSHIFT) + +struct kqueue; + +/* + * Locking: + * a atomic operations + * f fd_lock + * f/w fd_lock when writing + * k kernel lock + * m fd_fplock + */ +struct filedesc { + struct file **fd_ofiles; /* [f/w,m] file structures for + * open files */ + char *fd_ofileflags; /* [f] per-process open file flags */ + struct vnode *fd_cdir; /* [k] current directory */ + struct vnode *fd_rdir; /* [k] root directory */ + int fd_nfiles; /* [f] number of open files allocated */ + int fd_openfd; /* [f] number of files currently open */ + u_int *fd_himap; /* [f] each bit points to 32 fds */ + u_int *fd_lomap; /* [f] bitmap of free fds */ + int fd_lastfile; /* [f] high-water mark of fd_ofiles */ + int fd_freefile; /* [f] approx. next free file */ + u_short fd_cmask; /* [f/w] mask for file creation */ + u_short fd_refcnt; /* [k] reference count */ + struct rwlock fd_lock; /* lock for the file descs */ + struct mutex fd_fplock; /* lock for reading fd_ofiles without + * fd_lock */ + LIST_HEAD(, kqueue) fd_kqlist; /* [f] kqueues attached to this + * filedesc */ + int fd_flags; /* [a] flags on this filedesc */ +}; + +/* + * Basic allocation of descriptors: + * one of the above, plus arrays for NDFILE descriptors. + */ +struct filedesc0 { + struct filedesc fd_fd; + /* + * These arrays are used when the number of open files is + * <= NDFILE, and are then pointed to by the pointers above. + */ + struct file *fd_dfiles[NDFILE]; + char fd_dfileflags[NDFILE]; + /* + * There arrays are used when the number of open files is + * <= 1024, and are then pointed to by the pointers above. + */ + u_int fd_dhimap[NDENTRIES >> NDENTRYSHIFT]; + u_int fd_dlomap[NDENTRIES]; +}; + +/* + * Per-process open flags. + */ +#define UF_EXCLOSE 0x01 /* auto-close on exec */ +#define UF_PLEDGED 0x02 /* open after pledge(2) */ + +/* + * Flags on the file descriptor table. + */ +#define FD_ADVLOCK 0x01 /* May hold a POSIX adv. lock. */ + +/* + * Storage required per open file descriptor. + */ +#define OFILESIZE (sizeof(struct file *) + sizeof(char)) + +#ifdef _KERNEL +/* + * Kernel global variables and routines. + */ +void filedesc_init(void); +int dupfdopen(struct proc *, int, int); +int fdalloc(struct proc *p, int want, int *result); +void fdexpand(struct proc *); +struct file *fnew(struct proc *_p); +int falloc(struct proc *_p, struct file **_rfp, int *_rfd); +struct filedesc *fdinit(void); +struct filedesc *fdshare(struct process *); +struct filedesc *fdcopy(struct process *); +void fdfree(struct proc *p); +int fdrelease(struct proc *p, int); +void fdinsert(struct filedesc *, int, int, struct file *); +void fdremove(struct filedesc *, int); +void fdcloseexec(struct proc *); +struct file *fd_iterfile(struct file *, struct proc *); +struct file *fd_getfile(struct filedesc *, int); +struct file *fd_getfile_mode(struct filedesc *, int, int); +int fd_checkclosed(struct filedesc *, int, struct file *); + +int closef(struct file *, struct proc *); +int getsock(struct proc *, int, struct file **); + +#define fdplock(fdp) do { NET_ASSERT_UNLOCKED(); rw_enter_write(&(fdp)->fd_lock); } while (0) +#define fdpunlock(fdp) rw_exit_write(&(fdp)->fd_lock) +#define fdpassertlocked(fdp) rw_assert_wrlock(&(fdp)->fd_lock) +#endif |