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 * $FreeBSD$
31 */
32
33 #ifndef _SYS_FILEDESC_H_
34 #define _SYS_FILEDESC_H_
35
36 #include <sys/caprights.h>
37 #include <sys/queue.h>
38 #include <sys/event.h>
39 #include <sys/lock.h>
40 #include <sys/priority.h>
41 #include <sys/seq.h>
42 #include <sys/sx.h>
43
44 #include <machine/_limits.h>
45
46 struct filecaps {
47 cap_rights_t fc_rights; /* per-descriptor capability rights */
48 u_long *fc_ioctls; /* per-descriptor allowed ioctls */
49 int16_t fc_nioctls; /* fc_ioctls array size */
50 uint32_t fc_fcntls; /* per-descriptor allowed fcntls */
51 };
52
53 struct filedescent {
54 struct file *fde_file; /* file structure for open file */
55 struct filecaps fde_caps; /* per-descriptor rights */
56 uint8_t fde_flags; /* per-process open file flags */
57 seq_t fde_seq; /* keep file and caps in sync */
58 };
59 #define fde_rights fde_caps.fc_rights
60 #define fde_fcntls fde_caps.fc_fcntls
61 #define fde_ioctls fde_caps.fc_ioctls
62 #define fde_nioctls fde_caps.fc_nioctls
63 #define fde_change_size (offsetof(struct filedescent, fde_seq))
64
65 /*
66 * This structure is used for the management of descriptors. It may be
67 * shared by multiple processes.
68 */
69 #define NDSLOTTYPE u_long
70
71 struct filedesc {
72 struct filedescent *fd_ofiles; /* open files */
73 struct vnode *fd_cdir; /* current directory */
74 struct vnode *fd_rdir; /* root directory */
75 struct vnode *fd_jdir; /* jail root directory */
76 int fd_nfiles; /* number of open files allocated */
77 NDSLOTTYPE *fd_map; /* bitmap of free fds */
78 int fd_lastfile; /* high-water mark of fd_ofiles */
79 int fd_freefile; /* approx. next free file */
80 u_short fd_cmask; /* mask for file creation */
81 u_short fd_refcnt; /* thread reference count */
82 u_short fd_holdcnt; /* hold count on structure + mutex */
83 struct sx fd_sx; /* protects members of this struct */
84 struct kqlist fd_kqlist; /* list of kqueues on this filedesc */
85 int fd_holdleaderscount; /* block fdfree() for shared close() */
86 int fd_holdleaderswakeup; /* fdfree() needs wakeup */
87 };
88 #define fd_seq(fdp, fd) (&(fdp)->fd_ofiles[(fd)].fde_seq)
89
90 /*
91 * Structure to keep track of (process leader, struct fildedesc) tuples.
92 * Each process has a pointer to such a structure when detailed tracking
93 * is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor
94 * table to be shared by processes having different "p_leader" pointers
95 * and thus distinct POSIX style locks.
96 *
97 * fdl_refcount and fdl_holdcount are protected by struct filedesc mtx.
98 */
99 struct filedesc_to_leader {
100 int fdl_refcount; /* references from struct proc */
101 int fdl_holdcount; /* temporary hold during closef */
102 int fdl_wakeup; /* fdfree() waits on closef() */
103 struct proc *fdl_leader; /* owner of POSIX locks */
104 /* Circular list: */
105 struct filedesc_to_leader *fdl_prev;
106 struct filedesc_to_leader *fdl_next;
107 };
108
109 /*
110 * Per-process open flags.
111 */
112 #define UF_EXCLOSE 0x01 /* auto-close on exec */
113
114 #ifdef _KERNEL
115
116 /* Flags for do_dup() */
117 #define DUP_FIXED 0x1 /* Force fixed allocation. */
118 #define DUP_FCNTL 0x2 /* fcntl()-style errors. */
119 #define DUP_CLOEXEC 0x4 /* Atomically set FD_CLOEXEC. */
120
121 /* Lock a file descriptor table. */
122 #define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure")
123 #define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx)
124 #define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx)
125 #define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx)
126 #define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx)
127 #define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx)
128 #define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx)
129
130 #define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \
131 SX_NOTRECURSED)
132 #define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \
133 SX_NOTRECURSED)
134 #define FILEDESC_UNLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_UNLOCKED)
135
136 struct thread;
137
138 void filecaps_init(struct filecaps *fcaps);
139 void filecaps_copy(const struct filecaps *src, struct filecaps *dst);
140 void filecaps_move(struct filecaps *src, struct filecaps *dst);
141 void filecaps_free(struct filecaps *fcaps);
142
143 int closef(struct file *fp, struct thread *td);
144 int do_dup(struct thread *td, int flags, int old, int new,
145 register_t *retval);
146 int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode,
147 int openerror, int *indxp);
148 int falloc(struct thread *td, struct file **resultfp, int *resultfd,
149 int flags);
150 int falloc_noinstall(struct thread *td, struct file **resultfp);
151 int finstall(struct thread *td, struct file *fp, int *resultfp, int flags,
152 struct filecaps *fcaps);
153 int fdalloc(struct thread *td, int minfd, int *result);
154 int fdallocn(struct thread *td, int minfd, int *fds, int n);
155 int fdavail(struct thread *td, int n);
156 int fdcheckstd(struct thread *td);
157 void fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td);
158 void fdcloseexec(struct thread *td);
159 struct filedesc *fdcopy(struct filedesc *fdp);
160 void fdunshare(struct thread *td);
161 void fdescfree(struct thread *td);
162 struct filedesc *fdinit(struct filedesc *fdp);
163 struct filedesc *fdshare(struct filedesc *fdp);
164 struct filedesc_to_leader *
165 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
166 struct filedesc *fdp, struct proc *leader);
167 int getvnode(struct filedesc *fdp, int fd, cap_rights_t *rightsp,
168 struct file **fpp);
169 void mountcheckdirs(struct vnode *olddp, struct vnode *newdp);
170 void setugidsafety(struct thread *td);
171
172 /* Return a referenced file from an unlocked descriptor. */
173 int fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
174 int needfcntl, struct file **fpp, cap_rights_t *haverightsp);
175
176 /* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */
177 static __inline struct file *
fget_locked(struct filedesc * fdp,int fd)178 fget_locked(struct filedesc *fdp, int fd)
179 {
180
181 FILEDESC_LOCK_ASSERT(fdp);
182
183 if (fd < 0 || fd > fdp->fd_lastfile)
184 return (NULL);
185
186 return (fdp->fd_ofiles[fd].fde_file);
187 }
188
189 #endif /* _KERNEL */
190
191 #endif /* !_SYS_FILEDESC_H_ */
192