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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 1.7 2003/10/13 21:15:48 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. */
64 struct file **fd_ofiles; /* file structures for open files */
65 char *fd_ofileflags; /* per-process open file flags */
66 struct vnode *fd_cdir; /* current directory (phaseout) */
67 struct vnode *fd_rdir; /* root directory (phaseout) */
68 struct vnode *fd_jdir; /* jail root directory (phaseout) */
69 struct namecache *fd_ncdir; /* current directory */
70 struct namecache *fd_nrdir; /* root directory */
71 struct namecache *fd_njdir; /* jail directory */
72 int fd_nfiles; /* number of open files allocated */
73 u_short fd_lastfile; /* high-water mark of fd_ofiles */
74 u_short fd_freefile; /* approx. next free file */
75 u_short fd_cmask; /* mask for file creation */
76 u_short fd_refcnt; /* reference count */
78 int fd_knlistsize; /* size of knlist */
79 struct klist *fd_knlist; /* list of attached knotes */
80 u_long fd_knhashmask; /* size of knhash */
81 struct klist *fd_knhash; /* hash table for attached knotes */
82 int fd_holdleaderscount; /* block fdfree() for shared close() */
83 int fd_holdleaderswakeup; /* fdfree() needs wakeup */
87 * Basic allocation of descriptors:
88 * one of the above, plus arrays for NDFILE descriptors.
91 struct filedesc fd_fd;
93 * These arrays are used when the number of open files is
94 * <= NDFILE, and are then pointed to by the pointers above.
96 struct file *fd_dfiles[NDFILE];
97 char fd_dfileflags[NDFILE];
103 * Structure to keep track of (process leader, struct fildedesc) tuples.
104 * Each process has a pointer to such a structure when detailed tracking
105 * is needed. e.g. when rfork(RFPROC | RFMEM) causes a file descriptor
106 * table to be shared by processes having different "p_leader" pointers
107 * and thus distinct POSIX style locks.
109 struct filedesc_to_leader {
110 int fdl_refcount; /* references from struct proc */
111 int fdl_holdcount; /* temporary hold during closef */
112 int fdl_wakeup; /* fdfree() waits on closef() */
113 struct proc *fdl_leader; /* owner of POSIX locks */
115 struct filedesc_to_leader *fdl_prev;
116 struct filedesc_to_leader *fdl_next;
120 * Per-process open flags.
122 #define UF_EXCLOSE 0x01 /* auto-close on exec */
124 #define UF_MAPPED 0x02 /* mapped from device */
128 * Storage required per open file descriptor.
130 #define OFILESIZE (sizeof(struct file *) + sizeof(char))
133 * This structure that holds the information needed to send a SIGIO or
134 * a SIGURG signal to a process or process group when new data arrives
135 * on a device or socket. The structure is placed on an SLIST belonging
136 * to the proc or pgrp so that the entire list may be revoked when the
137 * process exits or the process group disappears.
141 struct proc *siu_proc; /* process to receive SIGIO/SIGURG */
142 struct pgrp *siu_pgrp; /* process group to receive ... */
144 SLIST_ENTRY(sigio) sio_pgsigio; /* sigio's for process or group */
145 struct sigio **sio_myref; /* location of the pointer that holds
146 * the reference to this structure */
147 struct ucred *sio_ucred; /* current credentials */
148 uid_t sio_ruid; /* real user id */
149 pid_t sio_pgid; /* pgid for signals */
151 #define sio_proc sio_u.siu_proc
152 #define sio_pgrp sio_u.siu_pgrp
154 SLIST_HEAD(sigiolst, sigio);
162 * Kernel global variables and routines.
164 int dupfdopen (struct filedesc *, int, int, int, int);
165 int fdalloc (struct proc *p, int want, int *result);
166 int fdavail (struct proc *p, int n);
167 int falloc (struct proc *p, struct file **resultfp, int *resultfd);
168 void fsetcred(struct file *fp, struct ucred *cr);
169 void ffree (struct file *);
170 struct filedesc *fdinit (struct proc *p);
171 struct filedesc *fdshare (struct proc *p);
172 struct filedesc *fdcopy (struct proc *p);
173 void fdfree (struct proc *p);
174 int closef (struct file *fp, struct thread *td);
175 void fdcloseexec (struct proc *p);
176 int fdcheckstd (struct proc *p);
177 struct file *holdfp (struct filedesc *fdp, int fd, int flag);
178 int getvnode (struct filedesc *fdp, int fd, struct file **fpp);
179 int fdissequential (struct file *);
180 void fdsequential (struct file *, int);
181 pid_t fgetown (struct sigio *);
182 int fsetown (pid_t, struct sigio **);
183 void funsetown (struct sigio *);
184 void funsetownlst (struct sigiolst *);
185 void setugidsafety (struct proc *p);
187 struct filedesc_to_leader *
188 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
189 struct proc *leader);