bsd/sys/filedesc.h

   1 /*
   2  * Copyright (c) 2000-2012 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
  29 /*
  30  * Copyright (c) 1990, 1993
  31  *      The Regents of the University of California.  All rights reserved.
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 3. All advertising materials mentioning features or use of this software
  42  *    must display the following acknowledgement:
  43  *      This product includes software developed by the University of
  44  *      California, Berkeley and its contributors.
  45  * 4. Neither the name of the University nor the names of its contributors
  46  *    may be used to endorse or promote products derived from this software
  47  *    without specific prior written permission.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  59  * SUCH DAMAGE.
  60  *
  61  *      @(#)filedesc.h  8.1 (Berkeley) 6/2/93
  62  */
  63
  64 #ifndef _SYS_FILEDESC_H_
  65 #define _SYS_FILEDESC_H_
  66
  67 #include <sys/appleapiopts.h>
  68
  69 /*
  70  * This structure is used for the management of descriptors.  It may be
  71  * shared by multiple processes.
  72  *
  73  * A process is initially started out with NDFILE descriptors [XXXstored within
  74  * this structureXXX], selected to be enough for typical applications based on
  75  * the historical limit of 20 open files (and the usage of descriptors by
  76  * shells).  If these descriptors are exhausted, a larger descriptor table
  77  * may be allocated, up to a process' resource limit; [XXXthe internal arrays
  78  * are then unusedXXX].  The initial expansion is set to NDEXTENT; each time
  79  * it runs out, it is doubled until the resource limit is reached. NDEXTENT
  80  * should be selected to be the biggest multiple of OFILESIZE (see below)
  81  * that will fit in a power-of-two sized piece of memory.
  82  */
  83 #define NDFILE          25              /* 125 bytes */
  84 #define NDEXTENT        50              /* 250 bytes in 256-byte alloc. */
  85
  86 #ifdef BSD_KERNEL_PRIVATE
  87
  88 #include <kern/locks.h>
  89
  90 struct klist;
  91 struct kqwllist;
  92
  93 struct filedesc {
  94         struct  fileproc **fd_ofiles;   /* file structures for open files */
  95         lck_mtx_t fd_kqhashlock;        /* lock for dynamic kqueue hash */
  96         u_long  fd_kqhashmask;          /* size of dynamic kqueue hash */
  97         struct  kqwllist *fd_kqhash;    /* hash table for dynamic kqueues */
  98         struct  kqworkq *fd_wqkqueue;   /* the workq kqueue */
  99         char    *fd_ofileflags;         /* per-process open file flags */
 100         struct  vnode *fd_cdir;         /* current directory */
 101         struct  vnode *fd_rdir;         /* root directory */
 102         int     fd_nfiles;              /* number of open files allocated */
 103         int     fd_lastfile;            /* high-water mark of fd_ofiles */
 104         int     fd_freefile;            /* approx. next free file */
 105         mode_t  fd_cmask;               /* mask for file creation */
 106         int     fd_flags;
 107         int     fd_knlistsize;          /* size of knlist */
 108         struct  klist *fd_knlist;       /* list of attached knotes */
 109         u_long  fd_knhashmask;          /* size of knhash */
 110         struct  klist *fd_knhash;       /* hash table for attached knotes */
 111         lck_mtx_t fd_knhashlock;        /* lock for hash table for attached knotes */
 112 };
 113
 114 /*
 115  * definitions for fd_flags;
 116  */
 117 #define FD_CHROOT       0x01    /* process was chrooted... keep track even */
 118                                 /* if we're force unmounted and unable to */
 119                                 /* take a vnode_ref on fd_rdir during a fork */
 120
 121 #define FD_WORKLOOP     0x02    /* process has created a kqworkloop that */
 122                                 /* requires manual cleanup on exit */
 123
 124 /*
 125  * Per-process open flags.
 126  */
 127 #define UF_EXCLOSE      0x01            /* auto-close on exec */
 128 #define UF_FORKCLOSE    0x02            /* auto-close on fork */
 129 #define UF_RESERVED     0x04            /* open pending / in progress */
 130 #define UF_CLOSING      0x08            /* close in progress */
 131 #define UF_RESVWAIT     0x10            /* close in progress */
 132 #define UF_INHERIT      0x20            /* "inherit-on-exec" */
 133
 134 #define UF_VALID_FLAGS  \
 135         (UF_EXCLOSE | UF_FORKCLOSE | UF_RESERVED | UF_CLOSING |\
 136         UF_RESVWAIT | UF_INHERIT)
 137
 138 /*
 139  * Storage required per open file descriptor.
 140  */
 141 #define OFILESIZE (sizeof(struct file *) + sizeof(char))
 142
 143 /*!
 144  * @struct fdt_iterator
 145  *
 146  * @brief
 147  * Type used to iterate a file descriptor table.
 148  */
 149 struct fdt_iterator {
 150         int              fdti_fd;
 151         struct fileproc *fdti_fp;
 152 };
 153
 154 /*!
 155  * @function fdt_next
 156  *
 157  * @brief
 158  * Seek the iterator forward.
 159  *
 160  * @param p
 161  * The process for which the file descriptor table is being iterated.
 162  *
 163  * @param fd
 164  * The current file file descriptor to scan from (exclusive).
 165  *
 166  * @param only_settled
 167  * When true, only fileprocs with @c UF_RESERVED set are returned.
 168  * If false, fileprocs that are in flux (@c UF_RESERVED is set) are returned.
 169  *
 170  * @returns
 171  * The next iterator position.
 172  * If @c fdti_fp is NULL, the iteration is done.
 173  */
 174 extern struct fdt_iterator
 175 fdt_next(proc_t p, int fd, bool only_settled);
 176
 177 /*!
 178  * @function fdt_next
 179  *
 180  * @brief
 181  * Seek the iterator backwards.
 182  *
 183  * @param p
 184  * The process for which the file descriptor table is being iterated.
 185  *
 186  * @param fd
 187  * The current file file descriptor to scan from (exclusive).
 188  *
 189  * @param only_settled
 190  * When true, only fileprocs with @c UF_RESERVED set are returned.
 191  * If false, fileprocs that are in flux (@c UF_RESERVED is set) are returned.
 192  *
 193  * @returns
 194  * The next iterator position.
 195  * If @c fdti_fp is NULL, the iteration is done.
 196  */
 197 extern struct fdt_iterator
 198 fdt_prev(proc_t p, int fd, bool only_settled);
 199
 200 /*!
 201  * @def fdt_foreach
 202  *
 203  * @brief
 204  * Convenience macro around @c fdt_next() to enumerates fileprocs in a process
 205  * file descriptor table.
 206  *
 207  * @param fp
 208  * The iteration variable.
 209  *
 210  * @param p
 211  * The process for which the file descriptor table is being iterated.
 212  */
 213 #define fdt_foreach(fp, p) \
 214         for (struct fdt_iterator __fdt_it = fdt_next(p, -1, true); \
 215             ((fp) = __fdt_it.fdti_fp); \
 216             __fdt_it = fdt_next(p, __fdt_it.fdti_fd, true))
 217
 218 /*!
 219  * @def fdt_foreach_fd
 220  *
 221  * @brief
 222  * When in an @c fdt_foreach() loop, return the current file descriptor
 223  * being inspected.
 224  */
 225 #define fdt_foreach_fd()  __fdt_it.fdti_fd
 226
 227 /*
 228  * Kernel global variables and routines.
 229  */
 230 extern int      dupfdopen(struct filedesc *fdp,
 231     int indx, int dfd, int mode, int error);
 232 extern int      fdalloc(proc_t p, int want, int *result);
 233 extern int      fdavail(proc_t p, int n);
 234 #define         fdfile(p, fd)                                   \
 235                         (&(p)->p_fd->fd_ofiles[(fd)])
 236 #define         fdflags(p, fd)                                  \
 237                         (&(p)->p_fd->fd_ofileflags[(fd)])
 238
 239 /*
 240  * Accesor macros for fd flags
 241  */
 242 #define FDFLAGS_GET(p, fd) (*fdflags(p, fd) & (UF_EXCLOSE|UF_FORKCLOSE))
 243 #define FDFLAGS_SET(p, fd, bits) \
 244            (*fdflags(p, fd) |= ((bits) & (UF_EXCLOSE|UF_FORKCLOSE)))
 245 #define FDFLAGS_CLR(p, fd, bits) \
 246            (*fdflags(p, fd) &= ~((bits) & (UF_EXCLOSE|UF_FORKCLOSE)))
 247
 248 extern int      falloc(proc_t p, struct fileproc **resultfp, int *resultfd, vfs_context_t ctx);
 249
 250 typedef struct fileproc *(*fp_allocfn_t)(void *);
 251 extern int      falloc_withalloc(proc_t p, struct fileproc **resultfp,
 252     int *resultfd, vfs_context_t ctx,
 253     fp_allocfn_t fp_zalloc, void *crarg);
 254
 255 extern struct   filedesc *fdcopy(proc_t p, struct vnode *uth_cdir);
 256 extern void     fdfree(proc_t p);
 257 extern void     fdexec(proc_t p, short flags, int self_exec);
 258
 259 #endif /* BSD_KERNEL_PRIVATE */
 260
 261 #endif /* !_SYS_FILEDESC_H_ */