bsd/sys/aio.h

   1 /*
   2  * Copyright (c) 2003-2006 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 /*
  29  *      File:   sys/aio.h
  30  *      Author: Umesh Vaishampayan [umeshv@apple.com]
  31  *                      05-Feb-2003     umeshv  Created.
  32  *
  33  *      Header file for POSIX Asynchronous IO APIs
  34  *
  35  */
  36
  37 #ifndef _SYS_AIO_H_
  38 #define _SYS_AIO_H_
  39
  40 #include <sys/signal.h>
  41 #include <sys/_types.h>
  42 #include <sys/cdefs.h>
  43
  44 /*
  45  * [XSI] Inclusion of the <aio.h> header may make visible symbols defined
  46  * in the headers <fcntl.h>, <signal.h>, <sys/types.h>, and <time.h>.
  47  *
  48  * In our case, this is limited to struct timespec, off_t and ssize_t.
  49  */
  50 #define __need_struct_timespec
  51 #include <sys/_structs.h>
  52
  53 #ifndef _OFF_T
  54 typedef __darwin_off_t  off_t;
  55 #define _OFF_T
  56 #endif
  57
  58 #ifndef _SSIZE_T
  59 #define _SSIZE_T
  60 typedef __darwin_ssize_t        ssize_t;
  61 #endif
  62
  63
  64 struct aiocb {
  65         int             aio_fildes;             /* File descriptor */
  66         off_t           aio_offset;             /* File offset */
  67         volatile void   *aio_buf;               /* Location of buffer */
  68         size_t          aio_nbytes;             /* Length of transfer */
  69         int             aio_reqprio;            /* Request priority offset */
  70         struct sigevent aio_sigevent;           /* Signal number and value */
  71         int             aio_lio_opcode;         /* Operation to be performed */
  72 };
  73
  74 #ifdef KERNEL
  75
  76 struct user_aiocb {
  77         int             aio_fildes;             /* File descriptor */
  78         off_t           aio_offset __attribute((aligned(8))); /* File offset */
  79         user_addr_t     aio_buf __attribute((aligned(8)));              /* Location of buffer */
  80         user_size_t     aio_nbytes;             /* Length of transfer */
  81         int             aio_reqprio;    /* Request priority offset */
  82         struct user_sigevent aio_sigevent __attribute((aligned(8)));    /* Signal number and value */
  83         int             aio_lio_opcode;         /* Operation to be performed */
  84 };
  85
  86 #endif // KERNEL
  87
  88 /*
  89  * aio_cancel() return values
  90  */
  91
  92 /*
  93  * none of the requested operations could be canceled since they are
  94  * already complete.
  95  */
  96 #define AIO_ALLDONE                     0x1
  97
  98 /* all requested operations have been canceled */
  99 #define AIO_CANCELED            0x2
 100
 101 /*
 102  * some of the requested operations could not be canceled since
 103  * they are in progress
 104  */
 105 #define AIO_NOTCANCELED         0x4
 106
 107
 108 /*
 109  * lio_listio operation options
 110  */
 111
 112 #define LIO_NOP                 0x0     /* option indicating that no transfer is requested */
 113 #define LIO_READ                0x1             /* option requesting a read */
 114 #define LIO_WRITE               0x2             /* option requesting a write */
 115
 116 /*
 117  * lio_listio() modes
 118  */
 119
 120 /*
 121  * A lio_listio() synchronization operation indicating
 122  * that the calling thread is to continue execution while
 123  * the lio_listio() operation is being performed, and no
 124  * notification is given when the operation is complete
 125  */
 126 #define LIO_NOWAIT              0x1
 127
 128 /*
 129  * A lio_listio() synchronization operation indicating
 130  * that the calling thread is to suspend until the
 131  * lio_listio() operation is complete.
 132  */
 133 #define LIO_WAIT                0x2
 134
 135 /*
 136  * Maximum number of operations in single lio_listio call
 137  */
 138 #define AIO_LISTIO_MAX          16
 139
 140 /*
 141  * A aio_fsync() options
 142  * that the calling thread is to continue execution while
 143  * the lio_listio() operation is being performed, and no
 144  * notification is given when the operation is complete
 145  */
 146
 147 #ifndef O_SYNC  /* XXX investigate documentation error */
 148 #define O_SYNC                  0x0080  /* queued IO is completed as if by fsync() */
 149 #endif
 150 #if 0 /* O_DSYNC - NOT SUPPORTED */
 151 #define O_DSYNC                 0x1             /* queued async IO is completed as if by fdatasync() */
 152 #endif
 153
 154 #ifndef KERNEL
 155 /*
 156  * Prototypes
 157  */
 158
 159 __BEGIN_DECLS
 160
 161 /*
 162  * Attempt to cancel one or more asynchronous I/O requests currently outstanding
 163  * against file descriptor fd. The aiocbp argument points to the asynchronous I/O
 164  * control block for a particular request to be canceled.  If aiocbp is NULL, then
 165  * all outstanding cancelable asynchronous I/O requests against fd shall be canceled.
 166  */
 167 int             aio_cancel( int fd,
 168                                         struct aiocb * aiocbp );
 169
 170 /*
 171  * Return the error status associated with the aiocb structure referenced by the
 172  * aiocbp argument. The error status for an asynchronous I/O operation is the errno
 173  * value that would be set by the corresponding read(), write(),  or fsync()
 174  * operation.  If the operation has not yet completed, then the error status shall
 175  * be equal to [EINPROGRESS].
 176  */
 177 int             aio_error( const struct aiocb * aiocbp );
 178
 179 /*
 180  * Asynchronously force all I/O operations associated with the file indicated by
 181  * the file descriptor aio_fildes member of the aiocb structure referenced by the
 182  * aiocbp argument and queued at the time of the call to aio_fsync() to the
 183  * synchronized I/O completion state.  The function call shall return when the
 184  * synchronization request has been initiated or queued.  op O_SYNC is the only
 185  * supported opertation at this time.
 186  * The aiocbp argument refers to an asynchronous I/O control block. The aiocbp
 187  * value may be used as an argument to aio_error() and aio_return() in order to
 188  * determine the error status and return status, respectively, of the asynchronous
 189  * operation while it is proceeding.  When the request is queued, the error status
 190  * for the operation is [EINPROGRESS]. When all data has been successfully
 191  * transferred, the error status shall be reset to reflect the success or failure
 192  * of the operation.
 193  */
 194 int             aio_fsync( int op,
 195                                    struct aiocb * aiocbp );
 196
 197 /*
 198  * Read aiocbp->aio_nbytes from the file associated with aiocbp->aio_fildes into
 199  * the buffer pointed to by aiocbp->aio_buf.  The function call shall return when
 200  * the read request has been initiated or queued.
 201  * The aiocbp value may be used as an argument to aio_error() and aio_return() in
 202  * order to determine the error status and return status, respectively, of the
 203  * asynchronous operation while it is proceeding. If an error condition is
 204  * encountered during queuing, the function call shall return without having
 205  * initiated or queued the request. The requested operation takes place at the
 206  * absolute position in the file as given by aio_offset, as if lseek() were called
 207  * immediately prior to the operation with an offset equal to aio_offset and a
 208  * whence equal to SEEK_SET.  After a successful call to enqueue an asynchronous
 209  * I/O operation, the value of the file offset for the file is unspecified.
 210  */
 211 int             aio_read( struct aiocb * aiocbp );
 212
 213 /*
 214  * Return the return status associated with the aiocb structure referenced by
 215  * the aiocbp argument.  The return status for an asynchronous I/O operation is
 216  * the value that would be returned by the corresponding read(), write(), or
 217  * fsync() function call.  If the error status for the operation is equal to
 218  * [EINPROGRESS], then the return status for the operation is undefined.  The
 219  * aio_return() function may be called exactly once to retrieve the return status
 220  * of a given asynchronous operation; thereafter, if the same aiocb structure
 221  * is used in a call to aio_return() or aio_error(), an error may be returned.
 222  * When the aiocb structure referred to by aiocbp is used to submit another
 223  * asynchronous operation, then aio_return() may be successfully used to
 224  * retrieve the return status of that operation.
 225  */
 226 ssize_t aio_return( struct aiocb * aiocbp );
 227
 228 /*
 229  * Suspend the calling thread until at least one of the asynchronous I/O
 230  * operations referenced by the aiocblist argument has completed, until a signal
 231  * interrupts the function, or, if timeout is not NULL, until the time
 232  * interval specified by timeout has passed.  If any of the aiocb structures
 233  * in the aiocblist correspond to completed asynchronous I/O operations (that is,
 234  * the error status for the operation is not equal to [EINPROGRESS]) at the
 235  * time of the call, the function shall return without suspending the calling
 236  * thread.  The aiocblist argument is an array of pointers to asynchronous I/O
 237  * control blocks.  The nent argument indicates the number of elements in the
 238  * array.  Each aiocb structure pointed to has been used in initiating an
 239  * asynchronous I/O request via aio_read(), aio_write(), or lio_listio(). This
 240  * array may contain NULL pointers, which are ignored.
 241  */
 242 int             aio_suspend( const struct aiocb *const aiocblist[],
 243                                          int nent,
 244                                          const struct timespec * timeoutp ) __DARWIN_ALIAS_C(aio_suspend);
 245
 246 /*
 247  * Write aiocbp->aio_nbytes to the file associated with aiocbp->aio_fildes from
 248  * the buffer pointed to by aiocbp->aio_buf.  The function shall return when the
 249  * write request has been initiated or, at a minimum, queued.
 250  * The aiocbp argument may be used as an argument to aio_error() and aio_return()
 251  * in order to determine the error status and return status, respectively, of the
 252  * asynchronous operation while it is proceeding.
 253  */
 254 int             aio_write( struct aiocb * aiocbp );
 255
 256 /*
 257  * Initiate a list of I/O requests with a single function call.  The mode
 258  * argument takes one of the values LIO_WAIT or LIO_NOWAIT and determines whether
 259  * the function returns when the I/O operations have been completed, or as soon
 260  * as the operations have been queued.  If the mode argument is LIO_WAIT, the
 261  * function shall wait until all I/O is complete and the sig argument shall be
 262  * ignored.
 263  * If the mode argument is LIO_NOWAIT, the function shall return immediately, and
 264  * asynchronous notification shall occur, according to the sig argument, when all
 265  * the I/O operations complete.  If sig is NULL, then no asynchronous notification
 266  * shall occur.
 267  */
 268 int             lio_listio( int mode,
 269                                         struct aiocb *const aiocblist[],
 270                                         int nent,
 271                                         struct sigevent *sigp );
 272 __END_DECLS
 273
 274 #endif /* KERNEL */
 275 #endif /* _SYS_AIO_H_ */