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 typedef enum {
 127         FTYPE_SIMPLE    = 0,
 128         FTYPE_GUARDED   = (1 << _FP_TYPESHIFT)
 129 } fileproc_type_t;
 130
 131 /* file types */
 132 typedef enum {
 133         DTYPE_VNODE     = 1,    /* file */
 134         DTYPE_SOCKET,           /* communications endpoint */
 135         DTYPE_PSXSHM,           /* POSIX Shared memory */
 136         DTYPE_PSXSEM,           /* POSIX Semaphores */
 137         DTYPE_KQUEUE,           /* kqueue */
 138         DTYPE_PIPE,             /* pipe */
 139         DTYPE_FSEVENTS,         /* fsevents */
 140         DTYPE_ATALK,            /* (obsolete) */
 141         DTYPE_NETPOLICY,        /* networking policy */
 142 } file_type_t;
 143
 144 /* defines for fg_lflags */
 145 // was  FG_TERM         0x01
 146 #define FG_INSMSGQ      0x02    /* insert to msgqueue pending .. */
 147 #define FG_WINSMSGQ     0x04    /* wait for the fielglob is in msgque */
 148 #define FG_RMMSGQ       0x08    /* the fileglob is being removed from msgqueue */
 149 #define FG_WRMMSGQ      0x10    /* wait for the fileglob to  be removed from msgqueue */
 150 #define FG_PORTMADE     0x20    /* a port was at some point created for this fileglob */
 151 #define FG_NOSIGPIPE    0x40    /* don't deliver SIGPIPE with EPIPE return */
 152 #define FG_OFF_LOCKED   0x80    /* Used as a mutex for offset changes (for vnodes) */
 153 #define FG_OFF_LOCKWANT 0x100   /* Somebody's wating for the lock */
 154 #define FG_CONFINED     0x200   /* fileglob confined to process, immutably */
 155 #define FG_HAS_OFDLOCK  0x400   /* Has or has had an OFD lock */
 156
 157 struct fileops {
 158         file_type_t     fo_type;        /* descriptor type */
 159         int (*fo_read)      (struct fileproc *fp, struct uio *uio,
 160             int flags, vfs_context_t ctx);
 161         int (*fo_write)     (struct fileproc *fp, struct uio *uio,
 162             int flags, vfs_context_t ctx);
 163 #define FOF_OFFSET      0x00000001      /* offset supplied to vn_write */
 164 #define FOF_PCRED       0x00000002      /* cred from proc, not current thread */
 165         int (*fo_ioctl)(struct fileproc *fp, u_long com,
 166             caddr_t data, vfs_context_t ctx);
 167         int (*fo_select)    (struct fileproc *fp, int which,
 168             void *wql, vfs_context_t ctx);
 169         int (*fo_close)     (struct fileglob *fg, vfs_context_t ctx);
 170         int (*fo_kqfilter)  (struct fileproc *fp, struct knote *, struct kevent_qos_s *);
 171         int (*fo_drain)     (struct fileproc *fp, vfs_context_t ctx);
 172 };
 173
 174 struct fileglob {
 175         LIST_ENTRY(fileglob) f_msglist;     /* list of files in unix messages */
 176         uint32_t             fg_flag;       /* (atomic) see fcntl.h */
 177         os_ref_atomic_t      fg_count;      /* reference count */
 178         uint32_t             fg_msgcount;   /* references from message queue */
 179         int32_t              fg_lflags;     /* file global flags */
 180         kauth_cred_t         fg_cred;       /* credentials associated with descriptor */
 181         const struct fileops *fg_ops;
 182         off_t                fg_offset;
 183         void                *fg_data;       /* vnode or socket or SHM or semaphore */
 184         void                *fg_vn_data;    /* Per fd vnode data, used for directories */
 185         lck_mtx_t            fg_lock;
 186 #if CONFIG_MACF
 187         struct label        *fg_label;      /* JMM - use the one in the cred? */
 188 #endif
 189 };
 190
 191 extern int maxfiles;                    /* kernel limit on number of open files */
 192 extern int nfiles;                      /* actual number of open files */
 193 extern int maxfilesperproc;
 194 os_refgrp_decl_extern(f_refgrp);        /* os_refgrp_t for file refcounts */
 195
 196 #define FILEGLOB_DTYPE(fg)              ((const file_type_t)((fg)->fg_ops->fo_type))
 197
 198 #pragma mark files (struct fileglob)
 199
 200 /*!
 201  * @function fg_ref
 202  *
 203  * @brief
 204  * Acquire a file reference on the specified file.
 205  *
 206  * @description
 207  * The @c proc must be locked while this operation is being performed
 208  * to avoid races with setting the FG_CONFINED flag.
 209  *
 210  * @param proc
 211  * The proc this file reference is taken on behalf of.
 212  *
 213  * @param fg
 214  * The specified file
 215  */
 216 void
 217 fg_ref(proc_t proc, struct fileglob *fg);
 218
 219 /*!
 220  * @function fg_drop_live
 221  *
 222  * @brief
 223  * Drops a file reference on the specified file that isn't the last one.
 224  *
 225  * @param fg
 226  * The file whose reference is being dropped.
 227  */
 228 void
 229 fg_drop_live(struct fileglob *fg);
 230
 231 /*!
 232  * @function fg_drop
 233  *
 234  * @brief
 235  * Drops a file reference on the specified file.
 236  *
 237  * @discussion
 238  * No locks should be held when calling this function.
 239  *
 240  * @param p
 241  * The process making the request,
 242  * or PROC_NULL if the file belongs to a message/fileport.
 243  *
 244  * @param fg
 245  * The file being closed.
 246  *
 247  * @returns
 248  * 0          Success
 249  * ???        Any error that @c fileops::fo_close can return
 250  */
 251 int
 252 fg_drop(proc_t p, struct fileglob *fg);
 253
 254 /*!
 255  * @function fg_sendable
 256  *
 257  * @brief
 258  * Returns whether a particular file can be sent over IPC.
 259  */
 260 bool
 261 fg_sendable(struct fileglob *fg);
 262
 263 #pragma mark file descriptor entries (struct fileproc)
 264
 265 /*!
 266  * @function fp_get_ftype
 267  *
 268  * @brief
 269  * Get the fileproc pointer for the given fd from the per process, with the
 270  * specified file type, and with an I/O reference.
 271  *
 272  * @param p
 273  * The process in which fd lives.
 274  *
 275  * @param fd
 276  * The file descriptor index to lookup.
 277  *
 278  * @param ftype
 279  * The required file type.
 280  *
 281  * @param err
 282  * The error to return if the file exists but isn't of the specified type.
 283  *
 284  * @param fpp
 285  * The returned fileproc when the call returns 0.
 286  *
 287  * @returns
 288  * 0            Success (@c fpp is set)
 289  * EBADF        Bad file descriptor
 290  * @c err       There is an entry, but it isn't of the specified type.
 291  */
 292 extern int
 293 fp_get_ftype(proc_t p, int fd, file_type_t ftype, int err, struct fileproc **fpp);
 294
 295 /*!
 296  * @function fp_get_noref_locked
 297  *
 298  * @brief
 299  * Get the fileproc pointer for the given fd from the per process
 300  * open file table without taking an explicit reference on it.
 301  *
 302  * @description
 303  * This function assumes that the @c proc_fdlock is held, as the caller
 304  * doesn't hold an I/O reference for the returned fileproc.
 305  *
 306  * Because there is no reference explicitly taken, the returned
 307  * fileproc pointer is only valid so long as the @c proc_fdlock
 308  * remains held by the caller.
 309  *
 310  * @param p
 311  * The process in which fd lives.
 312  *
 313  * @param fd
 314  * The file descriptor index to lookup.
 315  *
 316  * @returns
 317  * - the fileproc on success
 318  * - FILEPROC_NULL on error
 319  */
 320 extern struct fileproc *
 321 fp_get_noref_locked(proc_t p, int fd);
 322
 323 /*!
 324  * @function fp_get_noref_locked_with_iocount
 325  *
 326  * @brief
 327  * Similar to fp_get_noref_locked(), but allows returning files that are
 328  * closing.
 329  *
 330  * @discussion
 331  * Some parts of the kernel take I/O references on fileprocs but only remember
 332  * the file descriptor for which they did that.
 333  *
 334  * These interfaces later need to drop that reference, but if the file is
 335  * already closing, then fp_get_noref_locked() will refuse to resolve
 336  * the file descriptor.
 337  *
 338  * This interface allows the lookup (but will assert that the fileproc has
 339  * enouhg I/O references).
 340  *
 341  * @warning
 342  * New code should NOT use this function, it is required for interfaces
 343  * that acquire iocounts without remembering the fileproc pointer,
 344  * which is bad practice.
 345  */
 346 extern struct fileproc *
 347 fp_get_noref_locked_with_iocount(proc_t p, int fd);
 348
 349 /*!
 350  * @function fp_close_and_unlock
 351  *
 352  * @brief
 353  * Close the given file descriptor entry.
 354  *
 355  * @description
 356  * This function assumes that the @c proc_fdlock is held,
 357  * and that the caller holds no additional I/O reference
 358  * on the specified file descriptor entry.
 359  *
 360  * The @c proc_fdlock is unlocked upon return.
 361  *
 362  * @param p
 363  * The process in which fd lives.
 364  *
 365  * @param fd
 366  * The file descriptor index being closed.
 367  *
 368  * @param fp
 369  * The fileproc entry associated with @c fd.
 370  *
 371  * @returns
 372  * 0            Success
 373  * EBADF        Bad file descriptor
 374  * ???          Any error that @c fileops::fo_close can return.
 375  */
 376 extern int
 377 fp_close_and_unlock(proc_t p, int fd, struct fileproc *fp, int flags);
 378
 379 /* wrappers for fp->f_ops->fo_... */
 380 int fo_read(struct fileproc *fp, struct uio *uio, int flags, vfs_context_t ctx);
 381 int fo_write(struct fileproc *fp, struct uio *uio, int flags,
 382     vfs_context_t ctx);
 383 int fo_ioctl(struct fileproc *fp, u_long com, caddr_t data, vfs_context_t ctx);
 384 int fo_select(struct fileproc *fp, int which, void *wql, vfs_context_t ctx);
 385 int fo_close(struct fileglob *fg, vfs_context_t ctx);
 386 int fo_drain(struct fileproc *fp, vfs_context_t ctx);
 387 int fo_kqfilter(struct fileproc *fp, struct knote *kn, struct kevent_qos_s *kev);
 388
 389 /* Functions to use for unsupported fileops */
 390 int fo_no_read(struct fileproc *fp, struct uio *uio, int flags, vfs_context_t ctx);
 391 int fo_no_write(struct fileproc *fp, struct uio *uio, int flags,
 392     vfs_context_t ctx);
 393 int fo_no_ioctl(struct fileproc *fp, u_long com, caddr_t data, vfs_context_t ctx);
 394 int fo_no_select(struct fileproc *fp, int which, void *wql, vfs_context_t ctx);
 395 int fo_no_drain(struct fileproc *fp, vfs_context_t ctx);
 396 int fo_no_kqfilter(struct fileproc *, struct knote *, struct kevent_qos_s *kev);
 397
 398 int fp_tryswap(proc_t, int fd, struct fileproc *nfp);
 399 int fp_drop(struct proc *p, int fd, struct fileproc *fp, int locked);
 400 void fp_free(struct proc * p, int fd, struct fileproc * fp);
 401 int fp_lookup(struct proc *p, int fd, struct fileproc **resultfp, int locked);
 402 int fp_isguarded(struct fileproc *fp, u_int attribs);
 403 int fp_guard_exception(proc_t p, int fd, struct fileproc *fp, u_int attribs);
 404 struct nameidata;
 405 struct vnode_attr;
 406 int open1(vfs_context_t ctx, struct nameidata *ndp, int uflags,
 407     struct vnode_attr *vap, fp_allocfn_t fp_zalloc, void *cra,
 408     int32_t *retval);
 409 int chdir_internal(proc_t p, vfs_context_t ctx, struct nameidata *ndp, int per_thread);
 410 int kqueue_internal(struct proc *p, fp_allocfn_t, void *cra, int32_t *retval);
 411 void procfdtbl_releasefd(struct proc * p, int fd, struct fileproc * fp);
 412 extern struct fileproc *fileproc_alloc_init(void *crargs);
 413 extern void fileproc_free(struct fileproc *fp);
 414 extern void guarded_fileproc_free(struct fileproc *fp);
 415 extern void fg_vn_data_free(void *fgvndata);
 416 extern int nameiat(struct nameidata *ndp, int dirfd);
 417 extern int falloc_guarded(struct proc *p, struct fileproc **fp, int *fd,
 418     vfs_context_t ctx, const guardid_t *guard, u_int attrs);
 419 extern void fileproc_modify_vflags(struct fileproc *fp, fileproc_vflags_t vflags, boolean_t clearflags);
 420 fileproc_vflags_t fileproc_get_vflags(struct fileproc *fp);
 421
 422 #pragma mark internal version of syscalls
 423
 424 int fileport_makefd(proc_t p, ipc_port_t port, int uf_flags, int *fd);
 425 int dup2(proc_t p, int from, int to, int *fd);
 426 int close_nocancel(proc_t p, int fd);
 427
 428 #pragma GCC visibility pop
 429
 430 __END_DECLS
 431
 432 #endif /* XNU_KERNEL_PRIVATE */
 433
 434 #endif /* !_SYS_FILE_INTERNAL_H_ */