158 lines
6.0 KiB
C
158 lines
6.0 KiB
C
/* $OpenBSD: filedesc.h,v 1.46 2022/05/12 13:33:09 mvs Exp $ */
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/* $NetBSD: filedesc.h,v 1.14 1996/04/09 20:55:28 cgd Exp $ */
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/*
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)filedesc.h 8.1 (Berkeley) 6/2/93
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*/
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#include <sys/mutex.h>
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#include <sys/rwlock.h>
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/*
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* This structure is used for the management of descriptors. It may be
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* shared by multiple processes.
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*
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* A process is initially started out with NDFILE descriptors stored within
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* this structure, selected to be enough for typical applications based on
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* the historical limit of 20 open files (and the usage of descriptors by
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* shells). If these descriptors are exhausted, a larger descriptor table
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* may be allocated, up to a process' resource limit; the internal arrays
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* are then unused. The initial expansion is set to NDEXTENT; each time
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* it runs out, it is doubled until the resource limit is reached. NDEXTENT
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* should be selected to be the biggest multiple of OFILESIZE (see below)
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* that will fit in a power-of-two sized piece of memory.
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*/
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#define NDFILE 20
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#define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
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#define NDENTRIES 32 /* 32 fds per entry */
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#define NDENTRYMASK (NDENTRIES - 1)
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#define NDENTRYSHIFT 5 /* bits per entry */
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#define NDREDUCE(x) (((x) + NDENTRIES - 1) >> NDENTRYSHIFT)
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#define NDHISLOTS(x) (NDREDUCE(NDREDUCE(x)))
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#define NDLOSLOTS(x) (NDHISLOTS(x) << NDENTRYSHIFT)
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struct kqueue;
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/*
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* Locking:
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* a atomic operations
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* f fd_lock
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* f/w fd_lock when writing
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* K kernel lock
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* m fd_fplock
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*/
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struct filedesc {
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struct file **fd_ofiles; /* [f/w,m] file structures for
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* open files */
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char *fd_ofileflags; /* [f] per-process open file flags */
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struct vnode *fd_cdir; /* [K] current directory */
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struct vnode *fd_rdir; /* [K] root directory */
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int fd_nfiles; /* [f] number of open files allocated */
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int fd_openfd; /* [f] number of files currently open */
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u_int *fd_himap; /* [f] each bit points to 32 fds */
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u_int *fd_lomap; /* [f] bitmap of free fds */
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int fd_lastfile; /* [f] high-water mark of fd_ofiles */
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int fd_freefile; /* [f] approx. next free file */
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mode_t fd_cmask; /* [f/w] mask for file creation */
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u_int fd_refcnt; /* [K] reference count */
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struct rwlock fd_lock; /* lock for the file descs */
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struct mutex fd_fplock; /* lock for reading fd_ofiles without
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* fd_lock */
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LIST_HEAD(, kqueue) fd_kqlist; /* [f] kqueues attached to this
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* filedesc */
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int fd_flags; /* [a] flags on this filedesc */
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};
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/*
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* Basic allocation of descriptors:
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* one of the above, plus arrays for NDFILE descriptors.
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*/
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struct filedesc0 {
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struct filedesc fd_fd;
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/*
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* These arrays are used when the number of open files is
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* <= NDFILE, and are then pointed to by the pointers above.
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*/
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struct file *fd_dfiles[NDFILE];
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char fd_dfileflags[NDFILE];
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/*
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* There arrays are used when the number of open files is
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* <= 1024, and are then pointed to by the pointers above.
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*/
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u_int fd_dhimap[NDENTRIES >> NDENTRYSHIFT];
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u_int fd_dlomap[NDENTRIES];
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};
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/*
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* Per-process open flags.
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*/
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#define UF_EXCLOSE 0x01 /* auto-close on exec */
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#define UF_PLEDGED 0x02 /* open after pledge(2) */
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/*
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* Flags on the file descriptor table.
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*/
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#define FD_ADVLOCK 0x01 /* May hold a POSIX adv. lock. */
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/*
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* Storage required per open file descriptor.
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*/
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#define OFILESIZE (sizeof(struct file *) + sizeof(char))
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#ifdef _KERNEL
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/*
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* Kernel global variables and routines.
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*/
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void filedesc_init(void);
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int dupfdopen(struct proc *, int, int);
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int fdalloc(struct proc *p, int want, int *result);
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void fdexpand(struct proc *);
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struct file *fnew(struct proc *_p);
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int falloc(struct proc *_p, struct file **_rfp, int *_rfd);
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struct filedesc *fdinit(void);
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struct filedesc *fdshare(struct process *);
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struct filedesc *fdcopy(struct process *);
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void fdfree(struct proc *p);
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int fdrelease(struct proc *p, int);
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void fdinsert(struct filedesc *, int, int, struct file *);
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void fdremove(struct filedesc *, int);
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void fdcloseexec(struct proc *);
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struct file *fd_iterfile(struct file *, struct proc *);
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struct file *fd_getfile(struct filedesc *, int);
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struct file *fd_getfile_mode(struct filedesc *, int, int);
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int fd_checkclosed(struct filedesc *, int, struct file *);
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int closef(struct file *, struct proc *);
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int getsock(struct proc *, int, struct file **);
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#define fdplock(fdp) do { NET_ASSERT_UNLOCKED(); rw_enter_write(&(fdp)->fd_lock); } while (0)
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#define fdpunlock(fdp) rw_exit_write(&(fdp)->fd_lock)
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#define fdpassertlocked(fdp) rw_assert_wrlock(&(fdp)->fd_lock)
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#endif
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