FreeBSD/Linux Kernel Cross Reference
sys/sys/file.h

     /*-
      * Copyright (c) 1982, 1986, 1989, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)file.h      8.3 (Berkeley) 1/9/95
     * $FreeBSD$
     */
    
    #ifndef _SYS_FILE_H_
    #define _SYS_FILE_H_
    
    #ifndef _KERNEL
    #include <sys/types.h> /* XXX */
    #include <sys/fcntl.h>
    #include <sys/unistd.h>
    #else
    #include <sys/queue.h>
    #include <sys/_lock.h>
    #include <sys/_mutex.h>
    
    struct stat;
    struct thread;
    struct uio;
    struct knote;
    struct vnode;
    struct socket;
    
    
    #endif /* _KERNEL */
    
    #define DTYPE_VNODE     1       /* file */
    #define DTYPE_SOCKET    2       /* communications endpoint */
    #define DTYPE_PIPE      3       /* pipe */
    #define DTYPE_FIFO      4       /* fifo (named pipe) */
    #define DTYPE_KQUEUE    5       /* event queue */
    #define DTYPE_CRYPTO    6       /* crypto */
    #define DTYPE_MQUEUE    7       /* posix message queue */
    
    #ifdef _KERNEL
    
    struct file;
    struct ucred;
    
    typedef int fo_rdwr_t(struct file *fp, struct uio *uio,
                        struct ucred *active_cred, int flags,
                        struct thread *td);
    #define FOF_OFFSET      1       /* Use the offset in uio argument */
    typedef int fo_ioctl_t(struct file *fp, u_long com, void *data,
                        struct ucred *active_cred, struct thread *td);
    typedef int fo_poll_t(struct file *fp, int events,
                        struct ucred *active_cred, struct thread *td);
    typedef int fo_kqfilter_t(struct file *fp, struct knote *kn);
    typedef int fo_stat_t(struct file *fp, struct stat *sb,
                        struct ucred *active_cred, struct thread *td);
    typedef int fo_close_t(struct file *fp, struct thread *td);
    typedef int fo_flags_t;
    
    struct fileops {
            fo_rdwr_t       *fo_read;
            fo_rdwr_t       *fo_write;
            fo_ioctl_t      *fo_ioctl;
            fo_poll_t       *fo_poll;
            fo_kqfilter_t   *fo_kqfilter;
            fo_stat_t       *fo_stat;
            fo_close_t      *fo_close;
            fo_flags_t      fo_flags;       /* DFLAG_* below */
    };
    
    #define DFLAG_PASSABLE  0x01    /* may be passed via unix sockets. */
    #define DFLAG_SEEKABLE  0x02    /* seekable / nonsequential */
    
    /*
     * Kernel descriptor table.
     * One entry for each open kernel vnode and socket.
     *
    * Below is the list of locks that protects members in struct file.
    *
    * (fl) filelist_lock
    * (f)  f_mtx in struct file
    * none not locked
    */
   
   struct file {
           LIST_ENTRY(file) f_list;/* (fl) list of active files */
           short   f_type;         /* descriptor type */
           void    *f_data;        /* file descriptor specific data */
           u_int   f_flag;         /* see fcntl.h */
           struct mtx      *f_mtxp;        /* mutex to protect data */
           struct fileops *f_ops;  /* File operations */
           struct  ucred *f_cred;  /* credentials associated with descriptor */
           int     f_count;        /* (f) reference count */
           struct vnode *f_vnode;  /* NULL or applicable vnode */
   
           /* DFLAG_SEEKABLE specific fields */
           off_t   f_offset;
           short     f_vnread_flags; /* 
                                      * (f) home grown sleep lock for f_offset
                                      * Used only for shared vnode locking in
                                      * vnread()
                                      */
   #define  FOFFSET_LOCKED       0x1
   #define  FOFFSET_LOCK_WAITING 0x2                
           /* DTYPE_SOCKET specific fields */
           short   f_gcflag;       /* used by thread doing fd garbage collection */
   #define FMARK           0x1     /* mark during gc() */
   #define FDEFER          0x2     /* defer for next gc pass */
   #define FWAIT           0x4     /* gc is scanning message buffers */
           int     f_msgcount;     /* (f) references from message queue */
   
           /* DTYPE_VNODE specific fields */
           int     f_seqcount;     /*
                                    * count of sequential accesses -- cleared
                                    * by most seek operations.
                                    */
           off_t   f_nextoff;      /*
                                    * offset of next expected read or write
                                    */
           void    *f_label;       /* Place-holder for struct label pointer. */
   };
   
   #endif /* _KERNEL */
   
   /*
    * Userland version of struct file, for sysctl
    */
   struct xfile {
           size_t  xf_size;        /* size of struct xfile */
           pid_t   xf_pid;         /* owning process */
           uid_t   xf_uid;         /* effective uid of owning process */
           int     xf_fd;          /* descriptor number */
           void    *xf_file;       /* address of struct file */
           short   xf_type;        /* descriptor type */
           int     xf_count;       /* reference count */
           int     xf_msgcount;    /* references from message queue */
           off_t   xf_offset;      /* file offset */
           void    *xf_data;       /* file descriptor specific data */
           void    *xf_vnode;      /* vnode pointer */
           u_int   xf_flag;        /* flags (see fcntl.h) */
   };
   
   #ifdef _KERNEL
   
   #ifdef MALLOC_DECLARE
   MALLOC_DECLARE(M_FILE);
   #endif
   
   LIST_HEAD(filelist, file);
   extern struct filelist filehead; /* (fl) head of list of open files */
   extern struct fileops vnops;
   extern struct fileops badfileops;
   extern struct fileops socketops;
   extern int maxfiles;            /* kernel limit on number of open files */
   extern int maxfilesperproc;     /* per process limit on number of open files */
   extern int openfiles;           /* (fl) actual number of open files */
   extern struct sx filelist_lock; /* sx to protect filelist and openfiles */
   
   int fget(struct thread *td, int fd, struct file **fpp);
   int fget_read(struct thread *td, int fd, struct file **fpp);
   int fget_write(struct thread *td, int fd, struct file **fpp);
   int fdrop(struct file *fp, struct thread *td);
   
   /*
    * The socket operations are used a couple of places.
    * XXX: This is wrong, they should go through the operations vector for
    * XXX: sockets instead of going directly for the individual functions. /phk
    */
   fo_rdwr_t       soo_read;
   fo_rdwr_t       soo_write;
   fo_ioctl_t      soo_ioctl;
   fo_poll_t       soo_poll;
   fo_kqfilter_t   soo_kqfilter;
   fo_stat_t       soo_stat;
   fo_close_t      soo_close;
   
   /* Lock a file. */
   #define FILE_LOCK(f)    mtx_lock((f)->f_mtxp)
   #define FILE_UNLOCK(f)  mtx_unlock((f)->f_mtxp)
   #define FILE_LOCKED(f)  mtx_owned((f)->f_mtxp)
   #define FILE_LOCK_ASSERT(f, type) mtx_assert((f)->f_mtxp, (type))
   
   int fgetvp(struct thread *td, int fd, struct vnode **vpp);
   int fgetvp_read(struct thread *td, int fd, struct vnode **vpp);
   int fgetvp_write(struct thread *td, int fd, struct vnode **vpp);
   
   int fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp);
   void fputsock(struct socket *sp);
   
   #define fhold_locked(fp)                                                \
           do {                                                            \
                   FILE_LOCK_ASSERT(fp, MA_OWNED);                         \
                   (fp)->f_count++;                                        \
           } while (0)
   
   #define fhold(fp)                                                       \
           do {                                                            \
                   FILE_LOCK(fp);                                          \
                   (fp)->f_count++;                                        \
                   FILE_UNLOCK(fp);                                        \
           } while (0)
   
   static __inline fo_rdwr_t       fo_read;
   static __inline fo_rdwr_t       fo_write;
   static __inline fo_ioctl_t      fo_ioctl;
   static __inline fo_poll_t       fo_poll;
   static __inline fo_kqfilter_t   fo_kqfilter;
   static __inline fo_stat_t       fo_stat;
   static __inline fo_close_t      fo_close;
   
   static __inline int
   fo_read(fp, uio, active_cred, flags, td)
           struct file *fp;
           struct uio *uio;
           struct ucred *active_cred;
           int flags;
           struct thread *td;
   {
   
           return ((*fp->f_ops->fo_read)(fp, uio, active_cred, flags, td));
   }
   
   static __inline int
   fo_write(fp, uio, active_cred, flags, td)
           struct file *fp;
           struct uio *uio;
           struct ucred *active_cred;
           int flags;
           struct thread *td;
   {
   
           return ((*fp->f_ops->fo_write)(fp, uio, active_cred, flags, td));
   }
   
   static __inline int
   fo_ioctl(fp, com, data, active_cred, td)
           struct file *fp;
           u_long com;
           void *data;
           struct ucred *active_cred;
           struct thread *td;
   {
   
           return ((*fp->f_ops->fo_ioctl)(fp, com, data, active_cred, td));
   }
   
   static __inline int
   fo_poll(fp, events, active_cred, td)
           struct file *fp;
           int events;
           struct ucred *active_cred;
           struct thread *td;
   {
   
           return ((*fp->f_ops->fo_poll)(fp, events, active_cred, td));
   }
   
   static __inline int
   fo_stat(fp, sb, active_cred, td)
           struct file *fp;
           struct stat *sb;
           struct ucred *active_cred;
           struct thread *td;
   {
   
           return ((*fp->f_ops->fo_stat)(fp, sb, active_cred, td));
   }
   
   static __inline int
   fo_close(fp, td)
           struct file *fp;
           struct thread *td;
   {
   
           return ((*fp->f_ops->fo_close)(fp, td));
   }
   
   static __inline int
   fo_kqfilter(fp, kn)
           struct file *fp;
           struct knote *kn;
   {
   
           return ((*fp->f_ops->fo_kqfilter)(fp, kn));
   }
   
   #endif /* _KERNEL */
   
   #endif /* !SYS_FILE_H */

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