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 struct fdescenttbl {
66 int fdt_nfiles; /* number of open files allocated */
67 struct filedescent fdt_ofiles[0]; /* open files */
68 };
69 #define fd_seq(fdt, fd) (&(fdt)->fdt_ofiles[(fd)].fde_seq)
70
71 /*
72 * This structure is used for the management of descriptors. It may be
73 * shared by multiple processes.
74 */
75 #define NDSLOTTYPE u_long
76
77 struct filedesc {
78 struct fdescenttbl *fd_files; /* open files table */
79 struct vnode *fd_cdir; /* current directory */
80 struct vnode *fd_rdir; /* root directory */
81 struct vnode *fd_jdir; /* jail root directory */
82 NDSLOTTYPE *fd_map; /* bitmap of free fds */
83 int fd_lastfile; /* high-water mark of fd_ofiles */
84 int fd_freefile; /* approx. next free file */
85 u_short fd_cmask; /* mask for file creation */
86 int fd_refcnt; /* thread reference count */
87 int fd_holdcnt; /* hold count on structure + mutex */
88 struct sx fd_sx; /* protects members of this struct */
89 struct kqlist fd_kqlist; /* list of kqueues on this filedesc */
90 int fd_holdleaderscount; /* block fdfree() for shared close() */
91 int fd_holdleaderswakeup; /* fdfree() needs wakeup */
92 };
93
94 /*
95 * Structure to keep track of (process leader, struct fildedesc) tuples.
96 * Each process has a pointer to such a structure when detailed tracking
97 * is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor
98 * table to be shared by processes having different "p_leader" pointers
99 * and thus distinct POSIX style locks.
100 *
101 * fdl_refcount and fdl_holdcount are protected by struct filedesc mtx.
102 */
103 struct filedesc_to_leader {
104 int fdl_refcount; /* references from struct proc */
105 int fdl_holdcount; /* temporary hold during closef */
106 int fdl_wakeup; /* fdfree() waits on closef() */
107 struct proc *fdl_leader; /* owner of POSIX locks */
108 /* Circular list: */
109 struct filedesc_to_leader *fdl_prev;
110 struct filedesc_to_leader *fdl_next;
111 };
112 #define fd_nfiles fd_files->fdt_nfiles
113 #define fd_ofiles fd_files->fdt_ofiles
114
115 /*
116 * Per-process open flags.
117 */
118 #define UF_EXCLOSE 0x01 /* auto-close on exec */
119
120 #ifdef _KERNEL
121
122 /* Lock a file descriptor table. */
123 #define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure")
124 #define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx)
125 #define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx)
126 #define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx)
127 #define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx)
128 #define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx)
129 #define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx)
130
131 #define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \
132 SX_NOTRECURSED)
133 #define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \
134 SX_NOTRECURSED)
135 #define FILEDESC_UNLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_UNLOCKED)
136
137 /* Operation types for kern_dup(). */
138 enum {
139 FDDUP_NORMAL, /* dup() behavior. */
140 FDDUP_FCNTL, /* fcntl()-style errors. */
141 FDDUP_FIXED, /* Force fixed allocation. */
142 FDDUP_MUSTREPLACE, /* Target must exist. */
143 FDDUP_LASTMODE,
144 };
145
146 /* Flags for kern_dup(). */
147 #define FDDUP_FLAG_CLOEXEC 0x1 /* Atomically set UF_EXCLOSE. */
148
149 /* For backward compatibility. */
150 #define falloc(td, resultfp, resultfd, flags) \
151 falloc_caps(td, resultfp, resultfd, flags, NULL)
152
153 struct thread;
154
155 void filecaps_init(struct filecaps *fcaps);
156 int filecaps_copy(const struct filecaps *src, struct filecaps *dst,
157 bool locked);
158 void filecaps_move(struct filecaps *src, struct filecaps *dst);
159 void filecaps_free(struct filecaps *fcaps);
160
161 int closef(struct file *fp, struct thread *td);
162 int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode,
163 int openerror, int *indxp);
164 int falloc_caps(struct thread *td, struct file **resultfp, int *resultfd,
165 int flags, struct filecaps *fcaps);
166 int falloc_noinstall(struct thread *td, struct file **resultfp);
167 void _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags,
168 struct filecaps *fcaps);
169 int finstall(struct thread *td, struct file *fp, int *resultfd, int flags,
170 struct filecaps *fcaps);
171 int fdalloc(struct thread *td, int minfd, int *result);
172 int fdallocn(struct thread *td, int minfd, int *fds, int n);
173 int fdcheckstd(struct thread *td);
174 void fdclose(struct thread *td, struct file *fp, int idx);
175 void fdcloseexec(struct thread *td);
176 void fdsetugidsafety(struct thread *td);
177 struct filedesc *fdcopy(struct filedesc *fdp);
178 int fdcopy_remapped(struct filedesc *fdp, const int *fds, size_t nfds,
179 struct filedesc **newfdp);
180 void fdinstall_remapped(struct thread *td, struct filedesc *fdp);
181 void fdunshare(struct thread *td);
182 void fdescfree(struct thread *td);
183 void fdescfree_remapped(struct filedesc *fdp);
184 struct filedesc *fdinit(struct filedesc *fdp, bool prepfiles);
185 struct filedesc *fdshare(struct filedesc *fdp);
186 struct filedesc_to_leader *
187 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
188 struct filedesc *fdp, struct proc *leader);
189 int getvnode(struct thread *td, int fd, cap_rights_t *rightsp,
190 struct file **fpp);
191 void mountcheckdirs(struct vnode *olddp, struct vnode *newdp);
192
193 /* Return a referenced file from an unlocked descriptor. */
194 int fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
195 struct file **fpp, seq_t *seqp);
196
197 /* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */
198 static __inline struct file *
fget_locked(struct filedesc * fdp,int fd)199 fget_locked(struct filedesc *fdp, int fd)
200 {
201
202 FILEDESC_LOCK_ASSERT(fdp);
203
204 if (fd < 0 || fd > fdp->fd_lastfile)
205 return (NULL);
206
207 return (fdp->fd_ofiles[fd].fde_file);
208 }
209
210 static __inline bool
fd_modified(struct filedesc * fdp,int fd,seq_t seq)211 fd_modified(struct filedesc *fdp, int fd, seq_t seq)
212 {
213
214 return (!seq_consistent(fd_seq(fdp->fd_files, fd), seq));
215 }
216
217 /* cdir/rdir/jdir manipulation functions. */
218 void pwd_chdir(struct thread *td, struct vnode *vp);
219 int pwd_chroot(struct thread *td, struct vnode *vp);
220 void pwd_ensure_dirs(void);
221
222 #endif /* _KERNEL */
223
224 #endif /* !_SYS_FILEDESC_H_ */
225