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 u_short fd_refcnt; /* thread reference count */ 87 u_short 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 struct thread; 138 139 void filecaps_init(struct filecaps *fcaps); 140 void filecaps_copy(const struct filecaps *src, struct filecaps *dst); 141 void filecaps_move(struct filecaps *src, struct filecaps *dst); 142 void filecaps_free(struct filecaps *fcaps); 143 144 int closef(struct file *fp, struct thread *td); 145 int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode, 146 int openerror, int *indxp); 147 int falloc(struct thread *td, struct file **resultfp, int *resultfd, 148 int flags); 149 int falloc_noinstall(struct thread *td, struct file **resultfp); 150 int finstall(struct thread *td, struct file *fp, int *resultfp, int flags, 151 struct filecaps *fcaps); 152 int fdalloc(struct thread *td, int minfd, int *result); 153 int fdallocn(struct thread *td, int minfd, int *fds, int n); 154 int fdcheckstd(struct thread *td); 155 void fdclose(struct thread *td, struct file *fp, int idx); 156 void fdcloseexec(struct thread *td); 157 void fdsetugidsafety(struct thread *td); 158 struct filedesc *fdcopy(struct filedesc *fdp); 159 void fdunshare(struct thread *td); 160 void fdescfree(struct thread *td); 161 struct filedesc *fdinit(struct filedesc *fdp, bool prepfiles); 162 struct filedesc *fdshare(struct filedesc *fdp); 163 struct filedesc_to_leader * 164 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 165 struct filedesc *fdp, struct proc *leader); 166 int getvnode(struct filedesc *fdp, int fd, cap_rights_t *rightsp, 167 struct file **fpp); 168 void mountcheckdirs(struct vnode *olddp, struct vnode *newdp); 169 170 /* Return a referenced file from an unlocked descriptor. */ 171 int fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 172 struct file **fpp, seq_t *seqp); 173 174 /* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */ 175 static __inline struct file * 176 fget_locked(struct filedesc *fdp, int fd) 177 { 178 179 FILEDESC_LOCK_ASSERT(fdp); 180 181 if (fd < 0 || fd > fdp->fd_lastfile) 182 return (NULL); 183 184 return (fdp->fd_ofiles[fd].fde_file); 185 } 186 187 static __inline bool 188 fd_modified(struct filedesc *fdp, int fd, seq_t seq) 189 { 190 191 return (!seq_consistent(fd_seq(fdp->fd_files, fd), seq)); 192 } 193 194 #endif /* _KERNEL */ 195 196 #endif /* !_SYS_FILEDESC_H_ */ 197