2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
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15 * This product includes software developed by the University of
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33 * @(#)filedesc.h 8.1 (Berkeley) 6/2/93
37 #ifndef _SYS_FILEDESC_H_
38 #define _SYS_FILEDESC_H_
40 #include <sys/_lock.h>
41 #include <sys/_mutex.h>
42 #include <sys/queue.h>
45 * This structure is used for the management of descriptors. It may be
46 * shared by multiple processes.
48 * A process is initially started out with NDFILE descriptors stored within
49 * this structure, selected to be enough for typical applications based on
50 * the historical limit of 20 open files (and the usage of descriptors by
51 * shells). If these descriptors are exhausted, a larger descriptor table
52 * may be allocated, up to a process' resource limit; the internal arrays
53 * are then unused. The initial expansion is set to NDEXTENT; each time
54 * it runs out, it is doubled until the resource limit is reached. NDEXTENT
55 * should be selected to be the biggest multiple of OFILESIZE (see below)
56 * that will fit in a power-of-two sized piece of memory.
59 #define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
62 struct file **fd_ofiles; /* file structures for open files */
63 char *fd_ofileflags; /* per-process open file flags */
64 struct vnode *fd_cdir; /* current directory */
65 struct vnode *fd_rdir; /* root directory */
66 struct vnode *fd_jdir; /* jail root directory */
67 int fd_nfiles; /* number of open files allocated */
68 int fd_lastfile; /* high-water mark of fd_ofiles */
69 int fd_freefile; /* approx. next free file */
70 u_short fd_cmask; /* mask for file creation */
71 u_short fd_refcnt; /* reference count */
73 int fd_knlistsize; /* size of knlist */
74 struct klist *fd_knlist; /* list of attached knotes */
75 u_long fd_knhashmask; /* size of knhash */
76 struct klist *fd_knhash; /* hash table for attached knotes */
77 struct mtx fd_mtx; /* mtx to protect the members of struct filedesc */
81 * Basic allocation of descriptors:
82 * one of the above, plus arrays for NDFILE descriptors.
85 struct filedesc fd_fd;
87 * These arrays are used when the number of open files is
88 * <= NDFILE, and are then pointed to by the pointers above.
90 struct file *fd_dfiles[NDFILE];
91 char fd_dfileflags[NDFILE];
95 * Per-process open flags.
97 #define UF_EXCLOSE 0x01 /* auto-close on exec */
99 #define UF_MAPPED 0x02 /* mapped from device */
103 * Storage required per open file descriptor.
105 #define OFILESIZE (sizeof(struct file *) + sizeof(char))
108 * This structure holds the information needed to send a SIGIO or
109 * a SIGURG signal to a process or process group when new data arrives
110 * on a device or socket. The structure is placed on an SLIST belonging
111 * to the proc or pgrp so that the entire list may be revoked when the
112 * process exits or the process group disappears.
115 * (pg) locked by either the process or process group lock
119 struct proc *siu_proc; /* (c) process to receive SIGIO/SIGURG */
120 struct pgrp *siu_pgrp; /* (c) process group to receive ... */
122 SLIST_ENTRY(sigio) sio_pgsigio; /* (pg) sigio's for process or group */
123 struct sigio **sio_myref; /* (c) location of the pointer that holds
124 * the reference to this structure */
125 struct ucred *sio_ucred; /* (c) current credentials */
126 pid_t sio_pgid; /* (c) pgid for signals */
128 #define sio_proc sio_u.siu_proc
129 #define sio_pgrp sio_u.siu_pgrp
131 SLIST_HEAD(sigiolst, sigio);
135 /* Lock a file descriptor table. */
136 #define FILEDESC_LOCK(fd) mtx_lock(&(fd)->fd_mtx)
137 #define FILEDESC_UNLOCK(fd) mtx_unlock(&(fd)->fd_mtx)
138 #define FILEDESC_LOCKED(fd) mtx_owned(&(fd)->fd_mtx)
139 #define FILEDESC_LOCK_ASSERT(fd, type) mtx_assert(&(fd)->fd_mtx, (type))
141 int closef __P((struct file *fp, struct thread *p));
142 int dupfdopen __P((struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode,
144 int falloc __P((struct thread *p, struct file **resultfp, int *resultfd));
145 int fdalloc __P((struct thread *p, int want, int *result));
146 int fdavail __P((struct thread *td, int n));
147 void fdcloseexec __P((struct thread *td));
148 struct filedesc *fdcopy __P((struct thread *td));
149 void fdfree __P((struct thread *td));
150 struct filedesc *fdinit __P((struct thread *td));
151 struct filedesc *fdshare __P((struct proc *p));
152 void ffree __P((struct file *fp));
153 static __inline struct file * fget_locked __P((struct filedesc *fdp, int fd));
154 pid_t fgetown __P((struct sigio *sigio));
155 int fsetown __P((pid_t pgid, struct sigio **sigiop));
156 void funsetown __P((struct sigio *sigio));
157 void funsetownlst __P((struct sigiolst *sigiolst));
158 int getvnode __P((struct filedesc *fdp, int fd, struct file **fpp));
159 void setugidsafety __P((struct thread *td));
161 static __inline struct file *
163 struct filedesc *fdp;
167 /* u_int cast checks for negative descriptors. */
168 return ((u_int)fd >= fdp->fd_nfiles ? NULL : fdp->fd_ofiles[fd]);
173 #endif /* !_SYS_FILEDESC_H_ */