1 /* $OpenBSD: filedesc.h,v 1.46 2022/05/12 13:33:09 mvs Exp $ */ 2 /* $NetBSD: filedesc.h,v 1.14 1996/04/09 20:55:28 cgd Exp $ */ 3 4 /* 5 * Copyright (c) 1990, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)filedesc.h 8.1 (Berkeley) 6/2/93 33 */ 34 35 #include <sys/mutex.h> 36 #include <sys/rwlock.h> 37 /* 38 * This structure is used for the management of descriptors. It may be 39 * shared by multiple processes. 40 * 41 * A process is initially started out with NDFILE descriptors stored within 42 * this structure, selected to be enough for typical applications based on 43 * the historical limit of 20 open files (and the usage of descriptors by 44 * shells). If these descriptors are exhausted, a larger descriptor table 45 * may be allocated, up to a process' resource limit; the internal arrays 46 * are then unused. The initial expansion is set to NDEXTENT; each time 47 * it runs out, it is doubled until the resource limit is reached. NDEXTENT 48 * should be selected to be the biggest multiple of OFILESIZE (see below) 49 * that will fit in a power-of-two sized piece of memory. 50 */ 51 #define NDFILE 20 52 #define NDEXTENT 50 /* 250 bytes in 256-byte alloc. */ 53 #define NDENTRIES 32 /* 32 fds per entry */ 54 #define NDENTRYMASK (NDENTRIES - 1) 55 #define NDENTRYSHIFT 5 /* bits per entry */ 56 #define NDREDUCE(x) (((x) + NDENTRIES - 1) >> NDENTRYSHIFT) 57 #define NDHISLOTS(x) (NDREDUCE(NDREDUCE(x))) 58 #define NDLOSLOTS(x) (NDHISLOTS(x) << NDENTRYSHIFT) 59 60 struct kqueue; 61 62 /* 63 * Locking: 64 * a atomic operations 65 * f fd_lock 66 * f/w fd_lock when writing 67 * K kernel lock 68 * m fd_fplock 69 */ 70 struct filedesc { 71 struct file **fd_ofiles; /* [f/w,m] file structures for 72 * open files */ 73 char *fd_ofileflags; /* [f] per-process open file flags */ 74 struct vnode *fd_cdir; /* [K] current directory */ 75 struct vnode *fd_rdir; /* [K] root directory */ 76 int fd_nfiles; /* [f] number of open files allocated */ 77 int fd_openfd; /* [f] number of files currently open */ 78 u_int *fd_himap; /* [f] each bit points to 32 fds */ 79 u_int *fd_lomap; /* [f] bitmap of free fds */ 80 int fd_lastfile; /* [f] high-water mark of fd_ofiles */ 81 int fd_freefile; /* [f] approx. next free file */ 82 mode_t fd_cmask; /* [f/w] mask for file creation */ 83 u_int fd_refcnt; /* [K] reference count */ 84 struct rwlock fd_lock; /* lock for the file descs */ 85 struct mutex fd_fplock; /* lock for reading fd_ofiles without 86 * fd_lock */ 87 LIST_HEAD(, kqueue) fd_kqlist; /* [f] kqueues attached to this 88 * filedesc */ 89 int fd_flags; /* [a] flags on this filedesc */ 90 }; 91 92 /* 93 * Basic allocation of descriptors: 94 * one of the above, plus arrays for NDFILE descriptors. 95 */ 96 struct filedesc0 { 97 struct filedesc fd_fd; 98 /* 99 * These arrays are used when the number of open files is 100 * <= NDFILE, and are then pointed to by the pointers above. 101 */ 102 struct file *fd_dfiles[NDFILE]; 103 char fd_dfileflags[NDFILE]; 104 /* 105 * There arrays are used when the number of open files is 106 * <= 1024, and are then pointed to by the pointers above. 107 */ 108 u_int fd_dhimap[NDENTRIES >> NDENTRYSHIFT]; 109 u_int fd_dlomap[NDENTRIES]; 110 }; 111 112 /* 113 * Per-process open flags. 114 */ 115 #define UF_EXCLOSE 0x01 /* auto-close on exec */ 116 #define UF_PLEDGED 0x02 /* open after pledge(2) */ 117 118 /* 119 * Flags on the file descriptor table. 120 */ 121 #define FD_ADVLOCK 0x01 /* May hold a POSIX adv. lock. */ 122 123 /* 124 * Storage required per open file descriptor. 125 */ 126 #define OFILESIZE (sizeof(struct file *) + sizeof(char)) 127 128 #ifdef _KERNEL 129 /* 130 * Kernel global variables and routines. 131 */ 132 void filedesc_init(void); 133 int dupfdopen(struct proc *, int, int); 134 int fdalloc(struct proc *p, int want, int *result); 135 void fdexpand(struct proc *); 136 struct file *fnew(struct proc *_p); 137 int falloc(struct proc *_p, struct file **_rfp, int *_rfd); 138 struct filedesc *fdinit(void); 139 struct filedesc *fdshare(struct process *); 140 struct filedesc *fdcopy(struct process *); 141 void fdfree(struct proc *p); 142 int fdrelease(struct proc *p, int); 143 void fdinsert(struct filedesc *, int, int, struct file *); 144 void fdremove(struct filedesc *, int); 145 void fdcloseexec(struct proc *); 146 struct file *fd_iterfile(struct file *, struct proc *); 147 struct file *fd_getfile(struct filedesc *, int); 148 struct file *fd_getfile_mode(struct filedesc *, int, int); 149 int fd_checkclosed(struct filedesc *, int, struct file *); 150 151 int closef(struct file *, struct proc *); 152 int getsock(struct proc *, int, struct file **); 153 154 #define fdplock(fdp) do { NET_ASSERT_UNLOCKED(); rw_enter_write(&(fdp)->fd_lock); } while (0) 155 #define fdpunlock(fdp) rw_exit_write(&(fdp)->fd_lock) 156 #define fdpassertlocked(fdp) rw_assert_wrlock(&(fdp)->fd_lock) 157 #endif 158