bsd/sys/file_internal.h

   1 /*
   2  * Copyright (c) 2000-2016 Apple 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) 1982, 1986, 1989, 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  *      @(#)file.h      8.3 (Berkeley) 1/9/95
  62  */
  63
  64 #ifndef _SYS_FILE_INTERNAL_H_
  65 #define _SYS_FILE_INTERNAL_H_
  66
  67 #include <sys/appleapiopts.h>
  68 #include <sys/fcntl.h>
  69 #include <sys/unistd.h>
  70
  71 #ifdef XNU_KERNEL_PRIVATE
  72 #include <sys/errno.h>
  73 #include <sys/queue.h>
  74 #include <sys/cdefs.h>
  75 #include <sys/lock.h>
  76 #include <sys/file.h>
  77 #include <sys/filedesc.h>
  78 #include <sys/guarded.h>
  79 #include <os/refcnt.h>
  80
  81 __BEGIN_DECLS
  82
  83 #pragma GCC visibility push(hidden)
  84
  85 struct proc;
  86 struct uio;
  87 struct knote;
  88 struct kevent_qos_s;
  89 struct file;
  90 #ifndef _KAUTH_CRED_T
  91 #define _KAUTH_CRED_T
  92 typedef struct ucred *kauth_cred_t;
  93 typedef struct posix_cred *posix_cred_t;
  94 #endif  /* !_KAUTH_CRED_T */
  95
  96 __options_decl(fileproc_vflags_t, unsigned int, {
  97         FPV_NONE        = 0,
  98         FPV_DRAIN       = 0x01,
  99 });
 100
 101 /*
 102  * Kernel descriptor table.
 103  * One entry for each open kernel vnode and socket.
 104  */
 105 struct fileproc {
 106         unsigned int fp_flags;
 107         _Atomic fileproc_vflags_t fp_vflags;
 108         os_refcnt_t fp_iocount;
 109         struct fileglob * fp_glob;
 110         void *fp_wset;
 111 };
 112
 113 #define FILEPROC_NULL (struct fileproc *)0
 114
 115 #define FP_INSELECT     0x0004
 116 #define FP_AIOISSUED    0x0080
 117 #define FP_SELCONFLICT  0x0200  /* select conflict on an individual fp */
 118
 119 /* squeeze a "type" value into the upper flag bits */
 120
 121 #define _FP_TYPESHIFT   24
 122 #define FP_TYPEMASK     (0x7 << _FP_TYPESHIFT)  /* 8 "types" of fileproc */
 123
 124 #define FILEPROC_TYPE(fp)       ((fp)->fp_flags & FP_TYPEMASK)
 125
 126 #define FP_ISGUARDED(fp, attribs)  \
 127                 ((FILEPROC_TYPE(fp) == FTYPE_GUARDED) ? fp_isguarded(fp, attribs) : 0)
 128
 129 typedef enum {
 130         FTYPE_SIMPLE    = 0,
 131         FTYPE_GUARDED   = (1 << _FP_TYPESHIFT)
 132 } fileproc_type_t;
 133
 134 /* file types */
 135 typedef enum {
 136         DTYPE_VNODE     = 1,    /* file */
 137         DTYPE_SOCKET,           /* communications endpoint */
 138         DTYPE_PSXSHM,           /* POSIX Shared memory */
 139         DTYPE_PSXSEM,           /* POSIX Semaphores */
 140         DTYPE_KQUEUE,           /* kqueue */
 141         DTYPE_PIPE,             /* pipe */
 142         DTYPE_FSEVENTS,         /* fsevents */
 143         DTYPE_ATALK,            /* (obsolete) */
 144         DTYPE_NETPOLICY,        /* networking policy */
 145 } file_type_t;
 146
 147 /* defines for fg_lflags */
 148 // was  FG_TERM         0x01
 149 #define FG_INSMSGQ      0x02    /* insert to msgqueue pending .. */
 150 #define FG_WINSMSGQ     0x04    /* wait for the fielglob is in msgque */
 151 #define FG_RMMSGQ       0x08    /* the fileglob is being removed from msgqueue */
 152 #define FG_WRMMSGQ      0x10    /* wait for the fileglob to  be removed from msgqueue */
 153 #define FG_PORTMADE     0x20    /* a port was at some point created for this fileglob */
 154 #define FG_NOSIGPIPE    0x40    /* don't deliver SIGPIPE with EPIPE return */
 155 #define FG_OFF_LOCKED   0x80    /* Used as a mutex for offset changes (for vnodes) */
 156 #define FG_OFF_LOCKWANT 0x100   /* Somebody's wating for the lock */
 157 #define FG_CONFINED     0x200   /* fileglob confined to process, immutably */
 158 #define FG_HAS_OFDLOCK  0x400   /* Has or has had an OFD lock */
 159
 160 struct fileops {
 161         file_type_t     fo_type;        /* descriptor type */
 162         int (*fo_read)      (struct fileproc *fp, struct uio *uio,
 163             int flags, vfs_context_t ctx);
 164         int (*fo_write)     (struct fileproc *fp, struct uio *uio,
 165             int flags, vfs_context_t ctx);
 166 #define FOF_OFFSET      0x00000001      /* offset supplied to vn_write */
 167 #define FOF_PCRED       0x00000002      /* cred from proc, not current thread */
 168         int (*fo_ioctl)(struct fileproc *fp, u_long com,
 169             caddr_t data, vfs_context_t ctx);
 170         int (*fo_select)    (struct fileproc *fp, int which,
 171             void *wql, vfs_context_t ctx);
 172         int (*fo_close)     (struct fileglob *fg, vfs_context_t ctx);
 173         int (*fo_kqfilter)  (struct fileproc *fp, struct knote *, struct kevent_qos_s *);
 174         int (*fo_drain)     (struct fileproc *fp, vfs_context_t ctx);
 175 };
 176
 177 struct fileglob {
 178         LIST_ENTRY(fileglob) f_msglist;     /* list of files in unix messages */
 179         uint32_t             fg_flag;       /* (atomic) see fcntl.h */
 180         os_ref_atomic_t      fg_count;      /* reference count */
 181         uint32_t             fg_msgcount;   /* references from message queue */
 182         int32_t              fg_lflags;     /* file global flags */
 183         kauth_cred_t         fg_cred;       /* credentials associated with descriptor */
 184         const struct fileops *fg_ops;
 185         off_t                fg_offset;
 186         void                *fg_data;       /* vnode or socket or SHM or semaphore */
 187         void                *fg_vn_data;    /* Per fd vnode data, used for directories */
 188         lck_mtx_t            fg_lock;
 189 #if CONFIG_MACF
 190         struct label        *fg_label;      /* JMM - use the one in the cred? */
 191 #endif
 192 };
 193
 194 extern int maxfiles;                    /* kernel limit on number of open files */
 195 extern int nfiles;                      /* actual number of open files */
 196 extern int maxfilesperproc;
 197 os_refgrp_decl_extern(f_refgrp);        /* os_refgrp_t for file refcounts */
 198
 199 #define FILEGLOB_DTYPE(fg)              ((const file_type_t)((fg)->fg_ops->fo_type))
 200
 201 #pragma mark files (struct fileglob)
 202
 203 /*!
 204  * @function fg_ref
 205  *
 206  * @brief
 207  * Acquire a file reference on the specified file.
 208  *
 209  * @param fg
 210  * The specified file
 211  */
 212 void
 213 fg_ref(struct fileglob *fg);
 214
 215 /*!
 216  * @function fg_drop
 217  *
 218  * @brief
 219  * Drops a file reference on the specified file.
 220  *
 221  * @discussion
 222  * No locks should be held when calling this function.
 223  *
 224  * @param p
 225  * The process making the request,
 226  * or PROC_NULL if the file belongs to a message/fileport.
 227  *
 228  * @param fg
 229  * The file being closed.
 230  *
 231  * @returns
 232  * 0          Success
 233  * ???        Any error that @c fileops::fo_close can return
 234  */
 235 int
 236 fg_drop(proc_t p, struct fileglob *fg);
 237
 238 /*!
 239  * @function fg_sendable
 240  *
 241  * @brief
 242  * Returns whether a particular file can be sent over IPC.
 243  */
 244 bool
 245 fg_sendable(struct fileglob *fg);
 246
 247 #pragma mark file descriptor entries (struct fileproc)
 248
 249 /*!
 250  * @function fp_get_ftype
 251  *
 252  * @brief
 253  * Get the fileproc pointer for the given fd from the per process, with the
 254  * specified file type, and with an I/O reference.
 255  *
 256  * @param p
 257  * The process in which fd lives.
 258  *
 259  * @param fd
 260  * The file descriptor index to lookup.
 261  *
 262  * @param ftype
 263  * The required file type.
 264  *
 265  * @param err
 266  * The error to return if the file exists but isn't of the specified type.
 267  *
 268  * @param fpp
 269  * The returned fileproc when the call returns 0.
 270  *
 271  * @returns
 272  * 0            Success (@c fpp is set)
 273  * EBADF        Bad file descriptor
 274  * @c err       There is an entry, but it isn't of the specified type.
 275  */
 276 extern int
 277 fp_get_ftype(proc_t p, int fd, file_type_t ftype, int err, struct fileproc **fpp);
 278
 279 /*!
 280  * @function fp_get_noref_locked
 281  *
 282  * @brief
 283  * Get the fileproc pointer for the given fd from the per process
 284  * open file table without taking an explicit reference on it.
 285  *
 286  * @description
 287  * This function assumes that the @c proc_fdlock is held, as the caller
 288  * doesn't hold an I/O reference for the returned fileproc.
 289  *
 290  * Because there is no reference explicitly taken, the returned
 291  * fileproc pointer is only valid so long as the @c proc_fdlock
 292  * remains held by the caller.
 293  *
 294  * @param p
 295  * The process in which fd lives.
 296  *
 297  * @param fd
 298  * The file descriptor index to lookup.
 299  *
 300  * @returns
 301  * - the fileproc on success
 302  * - FILEPROC_NULL on error
 303  */
 304 extern struct fileproc *
 305 fp_get_noref_locked(proc_t p, int fd);
 306
 307 /*!
 308  * @function fp_get_noref_locked_with_iocount
 309  *
 310  * @brief
 311  * Similar to fp_get_noref_locked(), but allows returning files that are
 312  * closing.
 313  *
 314  * @discussion
 315  * Some parts of the kernel take I/O references on fileprocs but only remember
 316  * the file descriptor for which they did that.
 317  *
 318  * These interfaces later need to drop that reference, but if the file is
 319  * already closing, then fp_get_noref_locked() will refuse to resolve
 320  * the file descriptor.
 321  *
 322  * This interface allows the lookup (but will assert that the fileproc has
 323  * enouhg I/O references).
 324  *
 325  * @warning
 326  * New code should NOT use this function, it is required for interfaces
 327  * that acquire iocounts without remembering the fileproc pointer,
 328  * which is bad practice.
 329  */
 330 extern struct fileproc *
 331 fp_get_noref_locked_with_iocount(proc_t p, int fd);
 332
 333 /*!
 334  * @function fp_close_and_unlock
 335  *
 336  * @brief
 337  * Close the given file descriptor entry.
 338  *
 339  * @description
 340  * This function assumes that the @c proc_fdlock is held,
 341  * and that the caller holds no additional I/O reference
 342  * on the specified file descriptor entry.
 343  *
 344  * The @c proc_fdlock is unlocked upon return.
 345  *
 346  * @param p
 347  * The process in which fd lives.
 348  *
 349  * @param fd
 350  * The file descriptor index being closed.
 351  *
 352  * @param fp
 353  * The fileproc entry associated with @c fd.
 354  *
 355  * @returns
 356  * 0            Success
 357  * EBADF        Bad file descriptor
 358  * ???          Any error that @c fileops::fo_close can return.
 359  */
 360 extern int
 361 fp_close_and_unlock(proc_t p, int fd, struct fileproc *fp, int flags);
 362
 363 /* wrappers for fp->f_ops->fo_... */
 364 int fo_read(struct fileproc *fp, struct uio *uio, int flags, vfs_context_t ctx);
 365 int fo_write(struct fileproc *fp, struct uio *uio, int flags,
 366     vfs_context_t ctx);
 367 int fo_ioctl(struct fileproc *fp, u_long com, caddr_t data, vfs_context_t ctx);
 368 int fo_select(struct fileproc *fp, int which, void *wql, vfs_context_t ctx);
 369 int fo_close(struct fileglob *fg, vfs_context_t ctx);
 370 int fo_drain(struct fileproc *fp, vfs_context_t ctx);
 371 int fo_kqfilter(struct fileproc *fp, struct knote *kn, struct kevent_qos_s *kev);
 372
 373 /* Functions to use for unsupported fileops */
 374 int fo_no_read(struct fileproc *fp, struct uio *uio, int flags, vfs_context_t ctx);
 375 int fo_no_write(struct fileproc *fp, struct uio *uio, int flags,
 376     vfs_context_t ctx);
 377 int fo_no_ioctl(struct fileproc *fp, u_long com, caddr_t data, vfs_context_t ctx);
 378 int fo_no_select(struct fileproc *fp, int which, void *wql, vfs_context_t ctx);
 379 int fo_no_drain(struct fileproc *fp, vfs_context_t ctx);
 380 int fo_no_kqfilter(struct fileproc *, struct knote *, struct kevent_qos_s *kev);
 381
 382 int fp_tryswap(proc_t, int fd, struct fileproc *nfp);
 383 int fp_drop(struct proc *p, int fd, struct fileproc *fp, int locked);
 384 void fp_free(struct proc * p, int fd, struct fileproc * fp);
 385 int fp_lookup(struct proc *p, int fd, struct fileproc **resultfp, int locked);
 386 int fp_isguarded(struct fileproc *fp, u_int attribs);
 387 int fp_guard_exception(proc_t p, int fd, struct fileproc *fp, u_int attribs);
 388 struct nameidata;
 389 struct vnode_attr;
 390 int open1(vfs_context_t ctx, struct nameidata *ndp, int uflags,
 391     struct vnode_attr *vap, fp_allocfn_t fp_zalloc, void *cra,
 392     int32_t *retval);
 393 int chdir_internal(proc_t p, vfs_context_t ctx, struct nameidata *ndp, int per_thread);
 394 int kqueue_internal(struct proc *p, fp_allocfn_t, void *cra, int32_t *retval);
 395 void procfdtbl_releasefd(struct proc * p, int fd, struct fileproc * fp);
 396 extern struct fileproc *fileproc_alloc_init(void *crargs);
 397 extern void fileproc_free(struct fileproc *fp);
 398 extern void guarded_fileproc_free(struct fileproc *fp);
 399 extern void fg_vn_data_free(void *fgvndata);
 400 extern int nameiat(struct nameidata *ndp, int dirfd);
 401 extern int falloc_guarded(struct proc *p, struct fileproc **fp, int *fd,
 402     vfs_context_t ctx, const guardid_t *guard, u_int attrs);
 403 extern void fileproc_modify_vflags(struct fileproc *fp, fileproc_vflags_t vflags, boolean_t clearflags);
 404 fileproc_vflags_t fileproc_get_vflags(struct fileproc *fp);
 405
 406 #pragma mark internal version of syscalls
 407
 408 int fileport_makefd(proc_t p, ipc_port_t port, int uf_flags, int *fd);
 409 int dup2(proc_t p, int from, int to, int *fd);
 410 int close_nocancel(proc_t p, int fd);
 411
 412 #pragma GCC visibility pop
 413
 414 __END_DECLS
 415
 416 #endif /* XNU_KERNEL_PRIVATE */
 417
 418 #endif /* !_SYS_FILE_INTERNAL_H_ */