bsd/sys/aio.h

   1 /*
   2  * Copyright (c) 2003-2005 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/cdefs.h>
  42
  43 struct aiocb {
  44         int                                     aio_fildes;             /* File descriptor */
  45         off_t                           aio_offset;             /* File offset */
  46         volatile void           *aio_buf;               /* Location of buffer */
  47         size_t                          aio_nbytes;             /* Length of transfer */
  48         int                                     aio_reqprio;    /* Request priority offset */
  49         struct sigevent         aio_sigevent;   /* Signal number and value */
  50         int                                     aio_lio_opcode; /* Operation to be performed */
  51 };
  52
  53 // LP64todo - should this move?
  54 #ifdef KERNEL
  55
  56 struct user_aiocb {
  57         int                                     aio_fildes;             /* File descriptor */
  58         off_t                           aio_offset;             /* File offset */
  59         user_addr_t                     aio_buf __attribute((aligned(8)));              /* Location of buffer */
  60         user_size_t                     aio_nbytes;             /* Length of transfer */
  61         int                                     aio_reqprio;    /* Request priority offset */
  62         struct user_sigevent aio_sigevent __attribute((aligned(8)));    /* Signal number and value */
  63         int                                     aio_lio_opcode; /* Operation to be performed */
  64 };
  65
  66 #endif // KERNEL
  67
  68 /*
  69  * aio_cancel() return values
  70  */
  71
  72 /*
  73  * none of the requested operations could be canceled since they are
  74  * already complete.
  75  */
  76 #define AIO_ALLDONE                     0x1
  77
  78 /* all requested operations have been canceled */
  79 #define AIO_CANCELED            0x2
  80
  81 /*
  82  * some of the requested operations could not be canceled since
  83  * they are in progress
  84  */
  85 #define AIO_NOTCANCELED         0x4
  86
  87
  88 /*
  89  * lio_listio operation options
  90  */
  91
  92 #define LIO_NOP                 0x0     /* option indicating that no transfer is requested */
  93 #define LIO_READ                0x1             /* option requesting a read */
  94 #define LIO_WRITE               0x2             /* option requesting a write */
  95
  96 /*
  97  * lio_listio() modes
  98  */
  99
 100 /*
 101  * A lio_listio() synchronization operation indicating
 102  * that the calling thread is to continue execution while
 103  * the lio_listio() operation is being performed, and no
 104  * notification is given when the operation is complete
 105  */
 106 #define LIO_NOWAIT              0x1
 107
 108 /*
 109  * A lio_listio() synchronization operation indicating
 110  * that the calling thread is to suspend until the
 111  * lio_listio() operation is complete.
 112  */
 113 #define LIO_WAIT                0x2
 114
 115 /*
 116  * Maximum number of operations in single lio_listio call
 117  */
 118 #define AIO_LISTIO_MAX          16
 119
 120 /*
 121  * A aio_fsync() options
 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
 127 #ifndef O_SYNC  /* XXX investigate documentation error */
 128 #define O_SYNC                  0x0080  /* queued IO is completed as if by fsync() */
 129 #endif
 130 #if 0 /* O_DSYNC - NOT SUPPORTED */
 131 #define O_DSYNC                 0x1             /* queued async IO is completed as if by fdatasync() */
 132 #endif
 133
 134 #ifndef KERNEL
 135 /*
 136  * Prototypes
 137  */
 138
 139 __BEGIN_DECLS
 140
 141 /*
 142  * Attempt to cancel one or more asynchronous I/O requests currently outstanding
 143  * against file descriptor fd. The aiocbp argument points to the asynchronous I/O
 144  * control block for a particular request to be canceled.  If aiocbp is NULL, then
 145  * all outstanding cancelable asynchronous I/O requests against fd shall be canceled.
 146  */
 147 int             aio_cancel( int fd,
 148                                         struct aiocb * aiocbp );
 149
 150 /*
 151  * Return the error status associated with the aiocb structure referenced by the
 152  * aiocbp argument. The error status for an asynchronous I/O operation is the errno
 153  * value that would be set by the corresponding read(), write(),  or fsync()
 154  * operation.  If the operation has not yet completed, then the error status shall
 155  * be equal to [EINPROGRESS].
 156  */
 157 int             aio_error( const struct aiocb * aiocbp );
 158
 159 /*
 160  * Asynchronously force all I/O operations associated with the file indicated by
 161  * the file descriptor aio_fildes member of the aiocb structure referenced by the
 162  * aiocbp argument and queued at the time of the call to aio_fsync() to the
 163  * synchronized I/O completion state.  The function call shall return when the
 164  * synchronization request has been initiated or queued.  op O_SYNC is the only
 165  * supported opertation at this time.
 166  * The aiocbp argument refers to an asynchronous I/O control block. The aiocbp
 167  * value may be used as an argument to aio_error() and aio_return() in order to
 168  * determine the error status and return status, respectively, of the asynchronous
 169  * operation while it is proceeding.  When the request is queued, the error status
 170  * for the operation is [EINPROGRESS]. When all data has been successfully
 171  * transferred, the error status shall be reset to reflect the success or failure
 172  * of the operation.
 173  */
 174 int             aio_fsync( int op,
 175                                    struct aiocb * aiocbp );
 176
 177 /*
 178  * Read aiocbp->aio_nbytes from the file associated with aiocbp->aio_fildes into
 179  * the buffer pointed to by aiocbp->aio_buf.  The function call shall return when
 180  * the read request has been initiated or queued.
 181  * The aiocbp value may be used as an argument to aio_error() and aio_return() in
 182  * order to determine the error status and return status, respectively, of the
 183  * asynchronous operation while it is proceeding. If an error condition is
 184  * encountered during queuing, the function call shall return without having
 185  * initiated or queued the request. The requested operation takes place at the
 186  * absolute position in the file as given by aio_offset, as if lseek() were called
 187  * immediately prior to the operation with an offset equal to aio_offset and a
 188  * whence equal to SEEK_SET.  After a successful call to enqueue an asynchronous
 189  * I/O operation, the value of the file offset for the file is unspecified.
 190  */
 191 int             aio_read( struct aiocb * aiocbp );
 192
 193 /*
 194  * Return the return status associated with the aiocb structure referenced by
 195  * the aiocbp argument.  The return status for an asynchronous I/O operation is
 196  * the value that would be returned by the corresponding read(), write(), or
 197  * fsync() function call.  If the error status for the operation is equal to
 198  * [EINPROGRESS], then the return status for the operation is undefined.  The
 199  * aio_return() function may be called exactly once to retrieve the return status
 200  * of a given asynchronous operation; thereafter, if the same aiocb structure
 201  * is used in a call to aio_return() or aio_error(), an error may be returned.
 202  * When the aiocb structure referred to by aiocbp is used to submit another
 203  * asynchronous operation, then aio_return() may be successfully used to
 204  * retrieve the return status of that operation.
 205  */
 206 ssize_t aio_return( struct aiocb * aiocbp );
 207
 208 /*
 209  * Suspend the calling thread until at least one of the asynchronous I/O
 210  * operations referenced by the aiocblist argument has completed, until a signal
 211  * interrupts the function, or, if timeout is not NULL, until the time
 212  * interval specified by timeout has passed.  If any of the aiocb structures
 213  * in the aiocblist correspond to completed asynchronous I/O operations (that is,
 214  * the error status for the operation is not equal to [EINPROGRESS]) at the
 215  * time of the call, the function shall return without suspending the calling
 216  * thread.  The aiocblist argument is an array of pointers to asynchronous I/O
 217  * control blocks.  The nent argument indicates the number of elements in the
 218  * array.  Each aiocb structure pointed to has been used in initiating an
 219  * asynchronous I/O request via aio_read(), aio_write(), or lio_listio(). This
 220  * array may contain NULL pointers, which are ignored.
 221  */
 222 int             aio_suspend( const struct aiocb *const aiocblist[],
 223                                          int nent,
 224                                          const struct timespec * timeoutp );
 225
 226 /*
 227  * Write aiocbp->aio_nbytes to the file associated with aiocbp->aio_fildes from
 228  * the buffer pointed to by aiocbp->aio_buf.  The function shall return when the
 229  * write request has been initiated or, at a minimum, queued.
 230  * The aiocbp argument may be used as an argument to aio_error() and aio_return()
 231  * in order to determine the error status and return status, respectively, of the
 232  * asynchronous operation while it is proceeding.
 233  */
 234 int             aio_write( struct aiocb * aiocbp );
 235
 236 /*
 237  * Initiate a list of I/O requests with a single function call.  The mode
 238  * argument takes one of the values LIO_WAIT or LIO_NOWAIT and determines whether
 239  * the function returns when the I/O operations have been completed, or as soon
 240  * as the operations have been queued.  If the mode argument is LIO_WAIT, the
 241  * function shall wait until all I/O is complete and the sig argument shall be
 242  * ignored.
 243  * If the mode argument is LIO_NOWAIT, the function shall return immediately, and
 244  * asynchronous notification shall occur, according to the sig argument, when all
 245  * the I/O operations complete.  If sig is NULL, then no asynchronous notification
 246  * shall occur.
 247  */
 248 int             lio_listio( int mode,
 249                                         struct aiocb *const aiocblist[],
 250                                         int nent,
 251                                         struct sigevent *sigp );
 252 __END_DECLS
 253
 254 #endif /* KERNEL */
 255 #endif /* _SYS_AIO_H_ */