sys/sys/filedesc.h

   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  * 3. 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: src/sys/sys/filedesc.h,v 1.19.2.5 2003/06/06 20:21:32 tegge Exp $
  31  * $DragonFly: src/sys/sys/filedesc.h,v 1.20 2006/10/27 04:56:33 dillon Exp $
  32  */
  33
  34 #ifndef _SYS_FILEDESC_H_
  35 #define _SYS_FILEDESC_H_
  36
  37 #ifndef _SYS_TYPES_H_
  38 #include <sys/types.h>
  39 #endif
  40 #ifndef _SYS_QUEUE_H_
  41 #include <sys/queue.h>
  42 #endif
  43 #ifndef _SYS_SPINLOCK_H_
  44 #include <sys/spinlock.h>
  45 #endif
  46 #ifndef _SYS_NAMECACHE_H_
  47 #include <sys/namecache.h>
  48 #endif
  49
  50 /*
  51  * This structure is used for the management of descriptors.  It may be
  52  * shared by multiple processes.
  53  *
  54  * A process is initially started out with NDFILE descriptors stored within
  55  * this structure, selected to be enough for typical applications based on
  56  * the historical limit of 20 open files (and the usage of descriptors by
  57  * shells) and the constraint of being one less than a power of 2.
  58  * If these descriptors are exhausted, a larger descriptor table
  59  * may be allocated, up to a process' resource limit; the internal arrays
  60  * are then unused.  Each time the file table runs out, it is doubled until
  61  * the resource limit is reached.
  62  */
  63 #define NDFILE          15              /* must be of the form 2^n - 1 */
  64
  65 struct file;
  66 struct klist;
  67
  68 struct fdnode {
  69         struct file *fp;
  70         char    fileflags;
  71         char    unused01;
  72         char    unused02;
  73         char    reserved;               /* descriptor has been reserved */
  74         int     allocated;              /* subtree allocation count */
  75 };
  76
  77 struct filedesc {
  78         struct fdnode *fd_files;        /* file structures for open files */
  79         struct  vnode *fd_cdir;         /* current directory (phaseout) */
  80         struct  vnode *fd_rdir;         /* root directory (phaseout) */
  81         struct  vnode *fd_jdir;         /* jail root directory (phaseout) */
  82         struct  nchandle fd_ncdir;      /* current directory */
  83         struct  nchandle fd_nrdir;      /* root directory */
  84         struct  nchandle fd_njdir;      /* jail directory */
  85         int     fd_nfiles;              /* number of open files allocated */
  86         int     fd_lastfile;            /* high-water mark of fd_files */
  87         int     fd_freefile;            /* approx. next free file */
  88         int     fd_cmask;               /* mask for file creation */
  89         int     fd_refcnt;              /* reference count */
  90         int     fd_softrefs;            /* softrefs to prevent destruction */
  91         int     fd_holdleaderscount;    /* block fdfree() for shared close() */
  92         int     fd_holdleaderswakeup;   /* fdfree() needs wakeup */
  93         struct spinlock fd_spin;
  94         struct  fdnode  fd_builtin_files[NDFILE];
  95 };
  96
  97 /*
  98  * Structure to keep track of (process leader, struct fildedesc) tuples.
  99  * Each process has a pointer to such a structure when detailed tracking
 100  * is needed. e.g. when rfork(RFPROC | RFMEM) causes a file descriptor
 101  * table to be shared by processes having different "p_leader" pointers
 102  * and thus distinct POSIX style locks.
 103  */
 104 struct filedesc_to_leader {
 105         int             fdl_refcount;   /* references from struct proc */
 106         int             fdl_holdcount;  /* temporary hold during closef */
 107         int             fdl_wakeup;     /* fdfree() waits on closef() */
 108         struct proc     *fdl_leader;    /* owner of POSIX locks */
 109         /* Circular list */
 110         struct filedesc_to_leader *fdl_prev;
 111         struct filedesc_to_leader *fdl_next;
 112 };
 113
 114 /*
 115  * Per-process open flags.
 116  */
 117 #define UF_EXCLOSE      0x01            /* auto-close on exec */
 118
 119 /*
 120  * This structure that holds the information needed to send a SIGIO or
 121  * a SIGURG signal to a process or process group when new data arrives
 122  * on a device or socket.  The structure is placed on an SLIST belonging
 123  * to the proc or pgrp so that the entire list may be revoked when the
 124  * process exits or the process group disappears.
 125  */
 126 struct  sigio {
 127         union {
 128                 struct  proc *siu_proc; /* process to receive SIGIO/SIGURG */
 129                 struct  pgrp *siu_pgrp; /* process group to receive ... */
 130         } sio_u;
 131         SLIST_ENTRY(sigio) sio_pgsigio; /* sigio's for process or group */
 132         struct  sigio **sio_myref;      /* location of the pointer that holds */
 133         struct  ucred *sio_ucred;       /* current credentials */
 134         uid_t   sio_ruid;               /* real user id */
 135         pid_t   sio_pgid;               /* pgid for signals */
 136 };
 137 #define sio_proc        sio_u.siu_proc
 138 #define sio_pgrp        sio_u.siu_pgrp
 139
 140 SLIST_HEAD(sigiolst, sigio);
 141
 142 #ifdef _KERNEL
 143
 144 struct thread;
 145 struct proc;
 146 struct lwp;
 147
 148 /*
 149  * Kernel global variables and routines.
 150  */
 151 int     dupfdopen (struct filedesc *, int, int, int, int);
 152 int     fdalloc (struct proc *p, int want, int *result);
 153 int     fdavail (struct proc *p, int n);
 154 int     falloc (struct lwp *lp, struct file **resultfp, int *resultfd);
 155 void    fsetfd (struct filedesc *fdp, struct file *fp, int fd);
 156 int     fgetfdflags(struct filedesc *fdp, int fd, int *flagsp);
 157 int     fsetfdflags(struct filedesc *fdp, int fd, int add_flags);
 158 int     fclrfdflags(struct filedesc *fdp, int fd, int rem_flags);
 159 void    fsetcred (struct file *fp, struct ucred *cr);
 160 void    fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask);
 161 struct  filedesc *fdinit (struct proc *p);
 162 struct  filedesc *fdshare (struct proc *p);
 163 int     fdcopy (struct proc *p, struct filedesc **fpp);
 164 void    fdfree (struct proc *p, struct filedesc *repl);
 165 int     fdrevoke(void *f_data, short f_type, struct ucred *cred);
 166 int     closef (struct file *fp, struct proc *p);
 167 void    fdcloseexec (struct proc *p);
 168 int     fdcheckstd (struct lwp *lp);
 169 struct  file *holdfp (struct filedesc *fdp, int fd, int flag);
 170 int     holdsock (struct filedesc *fdp, int fdes, struct file **fpp);
 171 int     holdvnode (struct filedesc *fdp, int fd, struct file **fpp);
 172 int     fdissequential (struct file *);
 173 void    fdsequential (struct file *, int);
 174 pid_t   fgetown (struct sigio **);
 175 int     fsetown (pid_t, struct sigio **);
 176 void    funsetown (struct sigio **);
 177 void    funsetownlst (struct sigiolst *);
 178 void    setugidsafety (struct proc *p);
 179 void    allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data);
 180
 181 struct filedesc_to_leader *
 182 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
 183                          struct proc *leader);
 184
 185 #endif
 186
 187 #endif