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33 * @(#)filedesc.h 8.1 (Berkeley) 6/2/93
34 * $FreeBSD: src/sys/sys/filedesc.h,v 1.19.2.5 2003/06/06 20:21:32 tegge Exp $
35 * $DragonFly: src/sys/sys/filedesc.h,v 1.2 2003/06/17 04:28:58 dillon Exp $
38 #ifndef _SYS_FILEDESC_H_
39 #define _SYS_FILEDESC_H_
41 #include <sys/queue.h>
44 * This structure is used for the management of descriptors. It may be
45 * shared by multiple processes.
47 * A process is initially started out with NDFILE descriptors stored within
48 * this structure, selected to be enough for typical applications based on
49 * the historical limit of 20 open files (and the usage of descriptors by
50 * shells). If these descriptors are exhausted, a larger descriptor table
51 * may be allocated, up to a process' resource limit; the internal arrays
52 * are then unused. The initial expansion is set to NDEXTENT; each time
53 * it runs out, it is doubled until the resource limit is reached. NDEXTENT
54 * should be selected to be the biggest multiple of OFILESIZE (see below)
55 * that will fit in a power-of-two sized piece of memory.
58 #define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */
63 struct file **fd_ofiles; /* file structures for open files */
64 char *fd_ofileflags; /* per-process open file flags */
65 struct vnode *fd_cdir; /* current directory */
66 struct vnode *fd_rdir; /* root directory */
67 struct vnode *fd_jdir; /* jail root directory */
68 int fd_nfiles; /* number of open files allocated */
69 u_short fd_lastfile; /* high-water mark of fd_ofiles */
70 u_short fd_freefile; /* approx. next free file */
71 u_short fd_cmask; /* mask for file creation */
72 u_short fd_refcnt; /* reference count */
74 int fd_knlistsize; /* size of knlist */
75 struct klist *fd_knlist; /* list of attached knotes */
76 u_long fd_knhashmask; /* size of knhash */
77 struct klist *fd_knhash; /* hash table for attached knotes */
78 int fd_holdleaderscount; /* block fdfree() for shared close() */
79 int fd_holdleaderswakeup; /* fdfree() needs wakeup */
83 * Basic allocation of descriptors:
84 * one of the above, plus arrays for NDFILE descriptors.
87 struct filedesc fd_fd;
89 * These arrays are used when the number of open files is
90 * <= NDFILE, and are then pointed to by the pointers above.
92 struct file *fd_dfiles[NDFILE];
93 char fd_dfileflags[NDFILE];
99 * Structure to keep track of (process leader, struct fildedesc) tuples.
100 * Each process has a pointer to such a structure when detailed tracking
101 * is needed. e.g. when rfork(RFPROC | RFMEM) causes a file descriptor
102 * table to be shared by processes having different "p_leader" pointers
103 * and thus distinct POSIX style locks.
105 struct filedesc_to_leader {
106 int fdl_refcount; /* references from struct proc */
107 int fdl_holdcount; /* temporary hold during closef */
108 int fdl_wakeup; /* fdfree() waits on closef() */
109 struct proc *fdl_leader; /* owner of POSIX locks */
111 struct filedesc_to_leader *fdl_prev;
112 struct filedesc_to_leader *fdl_next;
116 * Per-process open flags.
118 #define UF_EXCLOSE 0x01 /* auto-close on exec */
120 #define UF_MAPPED 0x02 /* mapped from device */
124 * Storage required per open file descriptor.
126 #define OFILESIZE (sizeof(struct file *) + sizeof(char))
129 * This structure that holds the information needed to send a SIGIO or
130 * a SIGURG signal to a process or process group when new data arrives
131 * on a device or socket. The structure is placed on an SLIST belonging
132 * to the proc or pgrp so that the entire list may be revoked when the
133 * process exits or the process group disappears.
137 struct proc *siu_proc; /* process to receive SIGIO/SIGURG */
138 struct pgrp *siu_pgrp; /* process group to receive ... */
140 SLIST_ENTRY(sigio) sio_pgsigio; /* sigio's for process or group */
141 struct sigio **sio_myref; /* location of the pointer that holds
142 * the reference to this structure */
143 struct ucred *sio_ucred; /* current credentials */
144 uid_t sio_ruid; /* real user id */
145 pid_t sio_pgid; /* pgid for signals */
147 #define sio_proc sio_u.siu_proc
148 #define sio_pgrp sio_u.siu_pgrp
150 SLIST_HEAD(sigiolst, sigio);
154 * Kernel global variables and routines.
156 int dupfdopen __P((struct proc *, struct filedesc *, int, int, int, int));
157 int fdalloc __P((struct proc *p, int want, int *result));
158 int fdavail __P((struct proc *p, int n));
159 int falloc __P((struct proc *p, struct file **resultfp, int *resultfd));
160 void ffree __P((struct file *));
161 struct filedesc *fdinit __P((struct proc *p));
162 struct filedesc *fdshare __P((struct proc *p));
163 struct filedesc *fdcopy __P((struct proc *p));
164 void fdfree __P((struct proc *p));
165 int closef __P((struct file *fp,struct proc *p));
166 void fdcloseexec __P((struct proc *p));
167 int fdcheckstd __P((struct proc *p));
168 struct file *holdfp __P((struct filedesc* fdp, int fd, int flag));
169 int getvnode __P((struct filedesc *fdp, int fd, struct file **fpp));
170 int fdissequential __P((struct file *));
171 void fdsequential __P((struct file *, int));
172 pid_t fgetown __P((struct sigio *));
173 int fsetown __P((pid_t, struct sigio **));
174 void funsetown __P((struct sigio *));
175 void funsetownlst __P((struct sigiolst *));
176 void setugidsafety __P((struct proc *p));
178 struct filedesc_to_leader *
179 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
180 struct proc *leader);