/* $OpenBSD: filedesc.h,v 1.49 2026/03/08 16:41:19 deraadt 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 */ mode_t fd_cmask; /* [f/w] mask for file creation */ u_int 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 */ u_int fd_nuserevents; /* [a] number of kqueue user events */ }; /* * 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 /* opened after pledge(2) */ #define UF_FORKCLOSE 0x04 /* auto-close on fork */ #define UF_PLEDGEOPEN 0x08 /* opened with __pledge_open() */ /* * 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 fdprepforexec(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
