2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990, 1993
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31 * @(#)filedesc.h 8.1 (Berkeley) 6/2/93
35 #ifndef _SYS_FILEDESC_H_
36 #define _SYS_FILEDESC_H_
38 #include <sys/caprights.h>
39 #include <sys/queue.h>
40 #include <sys/event.h>
42 #include <sys/priority.h>
46 #include <sys/smr_types.h>
48 #include <machine/_limits.h>
51 cap_rights_t fc_rights; /* per-descriptor capability rights */
52 u_long *fc_ioctls; /* per-descriptor allowed ioctls */
53 int16_t fc_nioctls; /* fc_ioctls array size */
54 uint32_t fc_fcntls; /* per-descriptor allowed fcntls */
58 struct file *fde_file; /* file structure for open file */
59 struct filecaps fde_caps; /* per-descriptor rights */
60 uint8_t fde_flags; /* per-process open file flags */
61 seqc_t fde_seqc; /* keep file and caps in sync */
63 #define fde_rights fde_caps.fc_rights
64 #define fde_fcntls fde_caps.fc_fcntls
65 #define fde_ioctls fde_caps.fc_ioctls
66 #define fde_nioctls fde_caps.fc_nioctls
67 #define fde_change_size (offsetof(struct filedescent, fde_seqc))
70 int fdt_nfiles; /* number of open files allocated */
71 struct filedescent fdt_ofiles[0]; /* open files */
73 #define fd_seqc(fdt, fd) (&(fdt)->fdt_ofiles[(fd)].fde_seqc)
76 * This structure is used for the management of descriptors. It may be
77 * shared by multiple processes.
79 #define NDSLOTTYPE u_long
82 * This struct is copy-on-write and allocated from an SMR zone.
83 * All fields are constant after initialization apart from the reference count.
85 * Check pwd_* routines for usage.
88 volatile u_int pwd_refcount;
89 struct vnode *pwd_cdir; /* current directory */
90 struct vnode *pwd_rdir; /* root directory */
91 struct vnode *pwd_jdir; /* jail root directory */
93 typedef SMR_POINTER(struct pwd *) smrpwd_t;
96 struct fdescenttbl *fd_files; /* open files table */
97 smrpwd_t fd_pwd; /* directories */
98 NDSLOTTYPE *fd_map; /* bitmap of free fds */
99 int fd_freefile; /* approx. next free file */
100 u_short fd_cmask; /* mask for file creation */
101 int fd_refcnt; /* thread reference count */
102 int fd_holdcnt; /* hold count on structure + mutex */
103 struct sx fd_sx; /* protects members of this struct */
104 struct kqlist fd_kqlist; /* list of kqueues on this filedesc */
105 int fd_holdleaderscount; /* block fdfree() for shared close() */
106 int fd_holdleaderswakeup; /* fdfree() needs wakeup */
110 * Structure to keep track of (process leader, struct fildedesc) tuples.
111 * Each process has a pointer to such a structure when detailed tracking
112 * is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor
113 * table to be shared by processes having different "p_leader" pointers
114 * and thus distinct POSIX style locks.
116 * fdl_refcount and fdl_holdcount are protected by struct filedesc mtx.
118 struct filedesc_to_leader {
119 int fdl_refcount; /* references from struct proc */
120 int fdl_holdcount; /* temporary hold during closef */
121 int fdl_wakeup; /* fdfree() waits on closef() */
122 struct proc *fdl_leader; /* owner of POSIX locks */
124 struct filedesc_to_leader *fdl_prev;
125 struct filedesc_to_leader *fdl_next;
127 #define fd_nfiles fd_files->fdt_nfiles
128 #define fd_ofiles fd_files->fdt_ofiles
131 * Per-process open flags.
133 #define UF_EXCLOSE 0x01 /* auto-close on exec */
137 /* Lock a file descriptor table. */
138 #define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure")
139 #define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx)
140 #define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx)
141 #define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx)
142 #define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx)
143 #define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx)
144 #define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx)
146 #define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \
148 #define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \
150 #define FILEDESC_UNLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_UNLOCKED)
152 #define FILEDESC_LOCKED_LOAD_PWD(fdp) ({ \
153 struct filedesc *_fdp = (fdp); \
155 _pwd = smr_serialized_load(&(_fdp)->fd_pwd, \
156 (FILEDESC_LOCK_ASSERT(_fdp), true)); \
160 #define FILEDESC_XLOCKED_LOAD_PWD(fdp) ({ \
161 struct filedesc *_fdp = (fdp); \
163 _pwd = smr_serialized_load(&(_fdp)->fd_pwd, \
164 (FILEDESC_XLOCK_ASSERT(_fdp), true)); \
171 * Accessor for libkvm et al.
173 #define FILEDESC_KVM_LOAD_PWD(fdp) ({ \
174 struct filedesc *_fdp = (fdp); \
176 _pwd = smr_kvm_load(&(_fdp)->fd_pwd); \
184 /* Operation types for kern_dup(). */
186 FDDUP_NORMAL, /* dup() behavior. */
187 FDDUP_FCNTL, /* fcntl()-style errors. */
188 FDDUP_FIXED, /* Force fixed allocation. */
189 FDDUP_MUSTREPLACE, /* Target must exist. */
193 /* Flags for kern_dup(). */
194 #define FDDUP_FLAG_CLOEXEC 0x1 /* Atomically set UF_EXCLOSE. */
196 /* For backward compatibility. */
197 #define falloc(td, resultfp, resultfd, flags) \
198 falloc_caps(td, resultfp, resultfd, flags, NULL)
203 filecaps_init(struct filecaps *fcaps)
206 bzero(fcaps, sizeof(*fcaps));
207 fcaps->fc_nioctls = -1;
209 bool filecaps_copy(const struct filecaps *src, struct filecaps *dst,
211 void filecaps_move(struct filecaps *src, struct filecaps *dst);
212 void filecaps_free(struct filecaps *fcaps);
214 int closef(struct file *fp, struct thread *td);
215 int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode,
216 int openerror, int *indxp);
217 int falloc_caps(struct thread *td, struct file **resultfp, int *resultfd,
218 int flags, struct filecaps *fcaps);
219 int falloc_noinstall(struct thread *td, struct file **resultfp);
220 void _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags,
221 struct filecaps *fcaps);
222 int finstall(struct thread *td, struct file *fp, int *resultfd, int flags,
223 struct filecaps *fcaps);
224 int fdalloc(struct thread *td, int minfd, int *result);
225 int fdallocn(struct thread *td, int minfd, int *fds, int n);
226 int fdcheckstd(struct thread *td);
227 void fdclose(struct thread *td, struct file *fp, int idx);
228 void fdcloseexec(struct thread *td);
229 void fdsetugidsafety(struct thread *td);
230 struct filedesc *fdcopy(struct filedesc *fdp);
231 int fdcopy_remapped(struct filedesc *fdp, const int *fds, size_t nfds,
232 struct filedesc **newfdp);
233 void fdinstall_remapped(struct thread *td, struct filedesc *fdp);
234 void fdunshare(struct thread *td);
235 void fdescfree(struct thread *td);
236 void fdescfree_remapped(struct filedesc *fdp);
237 int fdlastfile(struct filedesc *fdp);
238 int fdlastfile_single(struct filedesc *fdp);
239 struct filedesc *fdinit(struct filedesc *fdp, bool prepfiles, int *lastfile);
240 struct filedesc *fdshare(struct filedesc *fdp);
241 struct filedesc_to_leader *
242 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
243 struct filedesc *fdp, struct proc *leader);
244 int getvnode(struct thread *td, int fd, cap_rights_t *rightsp,
246 void mountcheckdirs(struct vnode *olddp, struct vnode *newdp);
248 int fget_cap_locked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
249 struct file **fpp, struct filecaps *havecapsp);
250 int fget_cap(struct thread *td, int fd, cap_rights_t *needrightsp,
251 struct file **fpp, struct filecaps *havecapsp);
253 /* Return a referenced file from an unlocked descriptor. */
254 int fget_unlocked_seq(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
255 struct file **fpp, seqc_t *seqp);
256 int fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
259 /* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */
260 static __inline struct file *
261 fget_locked(struct filedesc *fdp, int fd)
264 FILEDESC_LOCK_ASSERT(fdp);
266 if (__predict_false((u_int)fd >= fdp->fd_nfiles))
269 return (fdp->fd_ofiles[fd].fde_file);
272 static __inline struct filedescent *
273 fdeget_locked(struct filedesc *fdp, int fd)
275 struct filedescent *fde;
277 FILEDESC_LOCK_ASSERT(fdp);
279 if (__predict_false((u_int)fd >= fdp->fd_nfiles))
282 fde = &fdp->fd_ofiles[fd];
283 if (__predict_false(fde->fde_file == NULL))
291 fd_modified(struct filedesc *fdp, int fd, seqc_t seqc)
294 return (!seqc_consistent(fd_seqc(fdp->fd_files, fd), seqc));
298 /* cdir/rdir/jdir manipulation functions. */
299 void pwd_chdir(struct thread *td, struct vnode *vp);
300 int pwd_chroot(struct thread *td, struct vnode *vp);
301 void pwd_ensure_dirs(void);
302 void pwd_set_rootvnode(void);
304 struct pwd *pwd_hold_filedesc(struct filedesc *fdp);
305 struct pwd *pwd_hold(struct thread *td);
306 void pwd_drop(struct pwd *pwd);
308 pwd_set(struct filedesc *fdp, struct pwd *newpwd)
311 smr_serialized_store(&fdp->fd_pwd, newpwd,
312 (FILEDESC_XLOCK_ASSERT(fdp), true));
314 struct pwd *pwd_get_smr(void);
318 #endif /* !_SYS_FILEDESC_H_ */