1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)filedesc.h 8.1 (Berkeley) 6/2/93
30 * $FreeBSD: stable/9/sys/sys/filedesc.h 252288 2013-06-27 02:27:13Z mjg $
31 */
32
33 #ifndef _SYS_FILEDESC_H_
34 #define _SYS_FILEDESC_H_
35
36 #include <sys/queue.h>
37 #include <sys/event.h>
38 #include <sys/lock.h>
39 #include <sys/priority.h>
40 #include <sys/sx.h>
41
42 #include <machine/_limits.h>
43
44 /*
45 * This structure is used for the management of descriptors. It may be
46 * shared by multiple processes.
47 */
48 #define NDSLOTTYPE u_long
49
50 struct filedesc {
51 struct file **fd_ofiles; /* file structures for open files */
52 char *fd_ofileflags; /* per-process open file flags */
53 struct vnode *fd_cdir; /* current directory */
54 struct vnode *fd_rdir; /* root directory */
55 struct vnode *fd_jdir; /* jail root directory */
56 int fd_nfiles; /* number of open files allocated */
57 NDSLOTTYPE *fd_map; /* bitmap of free fds */
58 int fd_lastfile; /* high-water mark of fd_ofiles */
59 int fd_freefile; /* approx. next free file */
60 u_short fd_cmask; /* mask for file creation */
61 u_short fd_refcnt; /* thread reference count */
62 u_short fd_holdcnt; /* hold count on structure + mutex */
63 struct sx fd_sx; /* protects members of this struct */
64 struct kqlist fd_kqlist; /* list of kqueues on this filedesc */
65 int fd_holdleaderscount; /* block fdfree() for shared close() */
66 int fd_holdleaderswakeup; /* fdfree() needs wakeup */
67 };
68
69 /*
70 * Structure to keep track of (process leader, struct fildedesc) tuples.
71 * Each process has a pointer to such a structure when detailed tracking
72 * is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor
73 * table to be shared by processes having different "p_leader" pointers
74 * and thus distinct POSIX style locks.
75 *
76 * fdl_refcount and fdl_holdcount are protected by struct filedesc mtx.
77 */
78 struct filedesc_to_leader {
79 int fdl_refcount; /* references from struct proc */
80 int fdl_holdcount; /* temporary hold during closef */
81 int fdl_wakeup; /* fdfree() waits on closef() */
82 struct proc *fdl_leader; /* owner of POSIX locks */
83 /* Circular list: */
84 struct filedesc_to_leader *fdl_prev;
85 struct filedesc_to_leader *fdl_next;
86 };
87
88 /*
89 * Per-process open flags.
90 */
91 #define UF_EXCLOSE 0x01 /* auto-close on exec */
92
93 #ifdef _KERNEL
94
95 /* Lock a file descriptor table. */
96 #define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure")
97 #define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx)
98 #define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx)
99 #define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx)
100 #define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx)
101 #define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx)
102 #define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx)
103
104 #define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \
105 SX_NOTRECURSED)
106 #define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \
107 SX_NOTRECURSED)
108
109 struct thread;
110
111 int closef(struct file *fp, struct thread *td);
112 int dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd,
113 int mode, int error);
114 int falloc(struct thread *td, struct file **resultfp, int *resultfd,
115 int flags);
116 int falloc_noinstall(struct thread *td, struct file **resultfp);
117 int finstall(struct thread *td, struct file *fp, int *resultfp, int flags);
118 int fdalloc(struct thread *td, int minfd, int *result);
119 int fdallocn(struct thread *td, int minfd, int *fds, int n);
120 int fdavail(struct thread *td, int n);
121 int fdcheckstd(struct thread *td);
122 void fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td);
123 void fdcloseexec(struct thread *td);
124 struct filedesc *fdcopy(struct filedesc *fdp);
125 void fdunshare(struct proc *p, struct thread *td);
126 void fdfree(struct thread *td);
127 struct filedesc *fdinit(struct filedesc *fdp);
128 struct filedesc *fdshare(struct filedesc *fdp);
129 struct filedesc_to_leader *
130 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
131 struct filedesc *fdp, struct proc *leader);
132 int getvnode(struct filedesc *fdp, int fd, cap_rights_t rights,
133 struct file **fpp);
134 void mountcheckdirs(struct vnode *olddp, struct vnode *newdp);
135 void setugidsafety(struct thread *td);
136
137 /* Return a referenced file from an unlocked descriptor. */
138 struct file *fget_unlocked(struct filedesc *fdp, int fd);
139
140 /* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */
141 static __inline struct file *
fget_locked(struct filedesc * fdp,int fd)142 fget_locked(struct filedesc *fdp, int fd)
143 {
144
145 return (fd < 0 || fd >= fdp->fd_nfiles ? NULL : fdp->fd_ofiles[fd]);
146 }
147
148 #endif /* _KERNEL */
149
150 #endif /* !_SYS_FILEDESC_H_ */
151