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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/queue.h>
43 * This structure is used for the management of descriptors. It may be
44 * shared by multiple processes.
46 * A process is initially started out with NDFILE descriptors stored within
47 * this structure, selected to be enough for typical applications based on
48 * the historical limit of 20 open files (and the usage of descriptors by
49 * shells). If these descriptors are exhausted, a larger descriptor table
50 * may be allocated, up to a process' resource limit; the internal arrays
51 * are then unused. The initial expansion is set to NDEXTENT; each time
52 * it runs out, it is doubled until the resource limit is reached. NDEXTENT
53 * should be selected to be the biggest multiple of OFILESIZE (see below)
54 * that will fit in a power-of-two sized piece of memory.
57 #define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
60 struct file **fd_ofiles; /* file structures for open files */
61 char *fd_ofileflags; /* per-process open file flags */
62 struct vnode *fd_cdir; /* current directory */
63 struct vnode *fd_rdir; /* root directory */
64 struct vnode *fd_jdir; /* jail root directory */
65 int fd_nfiles; /* number of open files allocated */
66 u_short fd_lastfile; /* high-water mark of fd_ofiles */
67 u_short fd_freefile; /* approx. next free file */
68 u_short fd_cmask; /* mask for file creation */
69 u_short fd_refcnt; /* reference count */
73 * Basic allocation of descriptors:
74 * one of the above, plus arrays for NDFILE descriptors.
77 struct filedesc fd_fd;
79 * These arrays are used when the number of open files is
80 * <= NDFILE, and are then pointed to by the pointers above.
82 struct file *fd_dfiles[NDFILE];
83 char fd_dfileflags[NDFILE];
87 * Per-process open flags.
89 #define UF_EXCLOSE 0x01 /* auto-close on exec */
90 #define UF_MAPPED 0x02 /* mapped from device */
93 * Storage required per open file descriptor.
95 #define OFILESIZE (sizeof(struct file *) + sizeof(char))
98 * This structure that holds the information needed to send a SIGIO or
99 * a SIGURG signal to a process or process group when new data arrives
100 * on a device or socket. The structure is placed on an SLIST belonging
101 * to the proc or pgrp so that the entire list may be revoked when the
102 * process exits or the process group disappears.
106 struct proc *siu_proc; /* process to receive SIGIO/SIGURG */
107 struct pgrp *siu_pgrp; /* process group to receive ... */
109 SLIST_ENTRY(sigio) sio_pgsigio; /* sigio's for process or group */
110 struct sigio **sio_myref; /* location of the pointer that holds
111 * the reference to this structure */
112 struct ucred *sio_ucred; /* current credentials */
113 uid_t sio_ruid; /* real user id */
114 pid_t sio_pgid; /* pgid for signals */
116 #define sio_proc sio_u.siu_proc
117 #define sio_pgrp sio_u.siu_pgrp
119 SLIST_HEAD(sigiolst, sigio);
123 * Kernel global variables and routines.
125 int dupfdopen __P((struct filedesc *, int, int, int, int));
126 int fdalloc __P((struct proc *p, int want, int *result));
127 int fdavail __P((struct proc *p, int n));
128 int falloc __P((struct proc *p, struct file **resultfp, int *resultfd));
129 void ffree __P((struct file *));
130 struct filedesc *fdinit __P((struct proc *p));
131 struct filedesc *fdshare __P((struct proc *p));
132 struct filedesc *fdcopy __P((struct proc *p));
133 void fdfree __P((struct proc *p));
134 int closef __P((struct file *fp,struct proc *p));
135 void fdcloseexec __P((struct proc *p));
136 int getvnode __P((struct filedesc *fdp, int fd, struct file **fpp));
137 int fdissequential __P((struct file *));
138 void fdsequential __P((struct file *, int));
139 pid_t fgetown __P((struct sigio *));
140 int fsetown __P((pid_t, struct sigio **));
141 void funsetown __P((struct sigio *));
142 void funsetownlst __P((struct sigiolst *));
143 void setugidsafety __P((struct proc *p));