171 lines
6.2 KiB
C
171 lines
6.2 KiB
C
/*
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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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* 4. 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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* $FreeBSD$
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*/
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#ifndef _SYS_FILEDESC_H_
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#define _SYS_FILEDESC_H_
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#include <sys/queue.h>
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#include <sys/_lock.h>
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#include <sys/_mutex.h>
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#include <machine/_limits.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.
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*/
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#define NDFILE 20
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#define NDSLOTTYPE u_long
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#define NDSLOTSIZE sizeof(NDSLOTTYPE)
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#define NDENTRIES (NDSLOTSIZE * __CHAR_BIT)
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#define NDSLOT(x) ((x) / NDENTRIES)
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#define NDBIT(x) ((NDSLOTTYPE)1 << ((x) % NDENTRIES))
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#define NDSLOTS(x) (((x) + NDENTRIES - 1) / NDENTRIES)
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struct filedesc {
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struct file **fd_ofiles; /* file structures for open files */
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char *fd_ofileflags; /* per-process open file flags */
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struct vnode *fd_cdir; /* current directory */
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struct vnode *fd_rdir; /* root directory */
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struct vnode *fd_jdir; /* jail root directory */
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int fd_nfiles; /* number of open files allocated */
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NDSLOTTYPE *fd_map; /* bitmap of free fds */
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int fd_lastfile; /* high-water mark of fd_ofiles */
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int fd_freefile; /* approx. next free file */
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u_short fd_cmask; /* mask for file creation */
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u_short fd_refcnt; /* reference count */
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int fd_knlistsize; /* size of knlist */
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struct klist *fd_knlist; /* list of attached knotes */
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u_long fd_knhashmask; /* size of knhash */
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struct klist *fd_knhash; /* hash table for attached knotes */
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struct mtx fd_mtx; /* protects members of this struct */
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int fd_holdleaderscount; /* block fdfree() for shared close() */
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int fd_holdleaderswakeup; /* fdfree() needs wakeup */
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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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NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)];
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};
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/*
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* Structure to keep track of (process leader, struct fildedesc) tuples.
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* Each process has a pointer to such a structure when detailed tracking
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* is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor
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* table to be shared by processes having different "p_leader" pointers
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* and thus distinct POSIX style locks.
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*
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* fdl_refcount and fdl_holdcount are protected by struct filedesc mtx.
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*/
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struct filedesc_to_leader {
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int fdl_refcount; /* references from struct proc */
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int fdl_holdcount; /* temporary hold during closef */
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int fdl_wakeup; /* fdfree() waits on closef() */
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struct proc *fdl_leader; /* owner of POSIX locks */
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/* Circular list: */
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struct filedesc_to_leader *fdl_prev;
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struct filedesc_to_leader *fdl_next;
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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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/*
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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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/* Lock a file descriptor table. */
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#define FILEDESC_LOCK(fd) mtx_lock(&(fd)->fd_mtx)
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#define FILEDESC_UNLOCK(fd) mtx_unlock(&(fd)->fd_mtx)
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#define FILEDESC_LOCKED(fd) mtx_owned(&(fd)->fd_mtx)
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#define FILEDESC_LOCK_ASSERT(fd, type) mtx_assert(&(fd)->fd_mtx, (type))
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#define FILEDESC_LOCK_DESC "filedesc structure"
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struct thread;
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int closef(struct file *fp, struct thread *td);
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int dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd,
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int mode, int error);
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int falloc(struct thread *td, struct file **resultfp, int *resultfd);
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int fdalloc(struct thread *td, int minfd, int *result);
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int fdavail(struct thread *td, int n);
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int fdcheckstd(struct thread *td);
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void fdcloseexec(struct thread *td);
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struct filedesc *fdcopy(struct filedesc *fdp);
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void fdfree(struct thread *td);
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struct filedesc *fdinit(struct filedesc *fdp);
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struct filedesc *fdshare(struct filedesc *fdp);
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void fdunused(struct filedesc *fdp, int fd);
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void fdused(struct filedesc *fdp, int fd);
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void ffree(struct file *fp);
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struct filedesc_to_leader *
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filedesc_to_leader_alloc(struct filedesc_to_leader *old,
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struct filedesc *fdp, struct proc *leader);
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int getvnode(struct filedesc *fdp, int fd, struct file **fpp);
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void setugidsafety(struct thread *td);
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static __inline struct file *
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fget_locked(struct filedesc *fdp, int fd)
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{
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return (fd < 0 || fd >= fdp->fd_nfiles ? NULL : fdp->fd_ofiles[fd]);
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}
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extern struct mtx fdesc_mtx;
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#endif /* _KERNEL */
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#endif /* !_SYS_FILEDESC_H_ */
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