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 #define NTDCACHEFD      4               /* max td's caching same fd */
  65
  66 struct file;
  67 struct klist;
  68 struct fdcache;
  69
  70 struct fdnode {
  71         struct file *fp;
  72         char    fileflags;
  73         char    isfull;
  74         char    iterator;
  75         char    reserved;               /* descriptor has been reserved */
  76         int     allocated;              /* subtree allocation count */
  77         struct fdcache *tdcache[NTDCACHEFD];
  78 };
  79
  80 struct filedesc {
  81         struct fdnode *fd_files;        /* file structures for open files */
  82         struct  vnode *fd_cdir;         /* current directory (phaseout) */
  83         struct  vnode *fd_rdir;         /* root directory (phaseout) */
  84         struct  vnode *fd_jdir;         /* jail root directory (phaseout) */
  85         struct  nchandle fd_ncdir;      /* current directory */
  86         struct  nchandle fd_nrdir;      /* root directory */
  87         struct  nchandle fd_njdir;      /* jail directory */
  88         int     fd_nfiles;              /* number of open files allocated */
  89         int     fd_lastfile;            /* high-water mark of fd_files */
  90         int     fd_freefile;            /* approx. next free file */
  91         int     fd_cmask;               /* mask for file creation */
  92         int     fd_refcnt;              /* reference count */
  93         int     fd_softrefs;            /* softrefs to prevent destruction */
  94         int     fd_holdleaderscount;    /* block fdfree() for shared close() */
  95         int     fd_holdleaderswakeup;   /* fdfree() needs wakeup */
  96         int     fd_closedcounter;       /* detect close() */
  97         struct spinlock fd_spin;
  98         struct  fdnode  fd_builtin_files[NDFILE];
  99 };
 100
 101 /*
 102  * Structure to keep track of (process leader, struct fildedesc) tuples.
 103  * Each process has a pointer to such a structure when detailed tracking
 104  * is needed. e.g. when rfork(RFPROC | RFMEM) causes a file descriptor
 105  * table to be shared by processes having different "p_leader" pointers
 106  * and thus distinct POSIX style locks.
 107  */
 108 struct filedesc_to_leader {
 109         int             fdl_refcount;   /* references from struct proc */
 110         int             fdl_holdcount;  /* temporary hold during closef */
 111         int             fdl_wakeup;     /* fdfree() waits on closef() */
 112         struct proc     *fdl_leader;    /* owner of POSIX locks */
 113         /* Circular list */
 114         struct filedesc_to_leader *fdl_prev;
 115         struct filedesc_to_leader *fdl_next;
 116 };
 117
 118 /*
 119  * Per-process open flags.
 120  */
 121 #define UF_EXCLOSE      0x01            /* auto-close on exec */
 122
 123 /*
 124  * This structure that holds the information needed to send a SIGIO or
 125  * a SIGURG signal to a process or process group when new data arrives
 126  * on a device or socket.  The structure is placed on an SLIST belonging
 127  * to the proc or pgrp so that the entire list may be revoked when the
 128  * process exits or the process group disappears.
 129  */
 130 struct  sigio {
 131         union {
 132                 struct  proc *siu_proc; /* process to receive SIGIO/SIGURG */
 133                 struct  pgrp *siu_pgrp; /* process group to receive ... */
 134         } sio_u;
 135         SLIST_ENTRY(sigio) sio_pgsigio; /* sigio's for process or group */
 136         struct  sigio **sio_myref;      /* location of the pointer that holds */
 137         struct  ucred *sio_ucred;       /* current credentials */
 138         uid_t   sio_ruid;               /* real user id */
 139         pid_t   sio_pgid;               /* pgid for signals */
 140 };
 141 #define sio_proc        sio_u.siu_proc
 142 #define sio_pgrp        sio_u.siu_pgrp
 143
 144 SLIST_HEAD(sigiolst, sigio);
 145
 146 #ifdef _KERNEL
 147
 148 struct thread;
 149 struct proc;
 150 struct lwp;
 151
 152 /*
 153  * Kernel global variables and routines.
 154  */
 155 int     dupfdopen (struct thread *, int, int, int, int);
 156 int     fdalloc (struct proc *p, int want, int *result);
 157 int     fdavail (struct proc *p, int n);
 158 int     falloc (struct lwp *lp, struct file **resultfp, int *resultfd);
 159 void    fsetfd (struct filedesc *fdp, struct file *fp, int fd);
 160 int     fgetfdflags(struct filedesc *fdp, int fd, int *flagsp);
 161 int     fsetfdflags(struct filedesc *fdp, int fd, int add_flags);
 162 int     fclrfdflags(struct filedesc *fdp, int fd, int rem_flags);
 163 void    fsetcred (struct file *fp, struct ucred *cr);
 164 void    fdinit_bootstrap(struct proc *p0, struct filedesc *fdp0, int cmask);
 165 struct  filedesc *fdinit (struct proc *p);
 166 struct  filedesc *fdshare (struct proc *p);
 167 int     fdcopy (struct proc *p, struct filedesc **fpp);
 168 void    fdfree (struct proc *p, struct filedesc *repl);
 169 int     fdrevoke(void *f_data, short f_type, struct ucred *cred);
 170 int     closef (struct file *fp, struct proc *p);
 171 void    fdcloseexec (struct proc *p);
 172 int     fdcheckstd (struct lwp *lp);
 173 struct  file *holdfp (struct thread *td, int fd, int flag);
 174 struct  file *holdfp_fdp (struct filedesc *fdp, int fd, int flag);
 175 struct  file *holdfp_fdp_locked (struct filedesc *fdp, int fd, int flag);
 176 int     holdsock (struct thread *td, int fdes, struct file **fpp);
 177 int     holdvnode (struct thread *td, int fd, struct file **fpp);
 178 void    dropfp(struct thread *td, int fd, struct file *fp);
 179 int     fdissequential (struct file *);
 180 void    fdsequential (struct file *, int);
 181 pid_t   fgetown (struct sigio **);
 182 int     fsetown (pid_t, struct sigio **);
 183 void    funsetown (struct sigio **);
 184 void    funsetownlst (struct sigiolst *);
 185 void    setugidsafety (struct proc *p);
 186 void    allfiles_scan_exclusive(int (*callback)(struct file *, void *), void *data);
 187 void    fexitcache(struct thread *td);
 188
 189 struct filedesc_to_leader *
 190 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
 191                          struct proc *leader);
 192
 193 #endif
 194
 195 #endif