mirror of git://sourceware.org/git/glibc.git
307 lines
9.3 KiB
C
307 lines
9.3 KiB
C
/* Handle general operations.
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Copyright (C) 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <aio.h>
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#include <errno.h>
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#include <pthread.h>
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#include <semaphore.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include "aio_misc.h"
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/* We need a list of pending operations. This is sorted according to
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the priority given in the aio_reqprio member. */
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aiocb_union *__aio_requests;
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/* Since the list is global we need a semaphore protecting it. */
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sem_t __aio_requests_sema;
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/* The initialization function. It gets automatically called if any
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aio_* function is used in the program. */
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static void
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__attribute__ ((unused))
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aio_initialize (void)
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{
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/* Initialize the semaphore. We allow exactly one user at a time. */
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sem_init (&__aio_requests_sema, 0, 1);
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}
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text_set_element (__libc_subinit, aio_initialize);
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/* The thread handler. */
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static void *handle_fildes_io (void *arg);
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/* The main function of the async I/O handling. It enqueues requests
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and if necessary starts and handles threads. */
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int
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__aio_enqueue_request (aiocb_union *aiocbp, int operation, int require_lock)
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{
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int result;
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int policy, prio;
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struct sched_param param;
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aiocb_union *runp;
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if (aiocbp->aiocb.aio_reqprio < 0
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|| aiocbp->aiocb.aio_reqprio > AIO_PRIO_DELTA_MAX)
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{
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/* Invalid priority value. */
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__set_errno (EINVAL);
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aiocbp->aiocb.__error_code = EINVAL;
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aiocbp->aiocb.__return_value = -1;
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return -1;
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}
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if (pthread_getschedparam (pthread_self (), &policy, ¶m) < 0)
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{
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/* Something went wrong. */
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aiocbp->aiocb.__error_code = errno;
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aiocbp->aiocb.__return_value = -1;
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return -1;
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}
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/* Compute priority for this request. */
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prio = param.sched_priority - aiocbp->aiocb.aio_reqprio;
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/* Get the semaphore. */
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if (require_lock)
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sem_wait (&__aio_requests_sema);
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runp = __aio_requests;
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/* First look whether the current file descriptor is currently
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worked with. */
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while (runp != NULL && runp->aiocb.aio_fildes < aiocbp->aiocb.aio_fildes)
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runp = (aiocb_union *) runp->aiocb.__next_fd;
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if (runp != NULL)
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{
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/* The current file descriptor is worked on. It makes no sense
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to start another thread since this new thread would have to
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wait for the previous one to terminate. Simply enqueue it
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after the running one according to the priority. */
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while (runp->aiocb.__next_prio != NULL
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&& runp->aiocb.__next_prio->__abs_prio >= prio)
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runp = (aiocb_union *) runp->aiocb.__next_prio;
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aiocbp->aiocb.__next_prio = runp->aiocb.__next_prio;
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aiocbp->aiocb.__abs_prio = prio;
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aiocbp->aiocb.__policy = policy;
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aiocbp->aiocb.aio_lio_opcode = operation;
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aiocbp->aiocb.__error_code = EINPROGRESS;
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aiocbp->aiocb.__return_value = 0;
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runp->aiocb.__next_prio = (struct aiocb *) aiocbp;
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result = 0;
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}
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else
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{
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/* We create a new thread for this file descriptor. The
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function which gets called will handle all available requests
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for this descriptor and when all are processed it will
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terminate. */
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pthread_t thid;
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pthread_attr_t attr;
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/* First enqueue the request (the list is empty). */
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aiocbp->aiocb.__next_fd = NULL;
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aiocbp->aiocb.__last_fd = NULL;
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aiocbp->aiocb.__next_prio = NULL;
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aiocbp->aiocb.__abs_prio = prio;
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aiocbp->aiocb.__policy = policy;
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aiocbp->aiocb.aio_lio_opcode = operation;
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aiocbp->aiocb.__error_code = EINPROGRESS;
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aiocbp->aiocb.__return_value = 0;
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/* Make sure the thread is created detached. */
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pthread_attr_init (&attr);
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pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
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/* Now try to start a thread. */
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if (pthread_create (&thid, &attr, handle_fildes_io, aiocbp) < 0)
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{
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result = -1;
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aiocbp->aiocb.__error_code = errno;
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aiocbp->aiocb.__return_value = -1;
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}
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else
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/* We managed to enqueue the request. All errors which can
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happen now can be recognized by calls to `aio_return' and
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`aio_error'. */
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result = 0;
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}
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/* Release the semaphore. */
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if (require_lock)
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sem_post (&__aio_requests_sema);
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return result;
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}
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static void *
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handle_fildes_io (void *arg)
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{
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pthread_t self = pthread_self ();
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struct sched_param param;
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aiocb_union *runp = (aiocb_union *) arg;
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int policy;
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int fildes = runp->aiocb.aio_fildes; /* This is always the same. */
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pthread_getschedparam (self, &policy, ¶m);
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do
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{
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/* Change the priority to the requested value (if necessary). */
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if (runp->aiocb.__abs_prio != param.sched_priority
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|| runp->aiocb.__policy != policy)
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{
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param.sched_priority = runp->aiocb.__abs_prio;
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policy = runp->aiocb.__policy;
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pthread_setschedparam (self, policy, ¶m);
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}
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/* Process request pointed to by RUNP. We must not be disturbed
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by signals. */
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if ((runp->aiocb.aio_lio_opcode & 127) == LIO_READ)
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{
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if (runp->aiocb.aio_lio_opcode & 128)
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runp->aiocb.__return_value =
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TEMP_FAILURE_RETRY (__pread64 (fildes,
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(void *) runp->aiocb64.aio_buf,
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runp->aiocb64.aio_nbytes,
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runp->aiocb64.aio_offset));
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else
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runp->aiocb.__return_value =
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TEMP_FAILURE_RETRY (__pread (fildes,
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(void *) runp->aiocb.aio_buf,
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runp->aiocb.aio_nbytes,
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runp->aiocb.aio_offset));
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}
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else if ((runp->aiocb.aio_lio_opcode & 127) == LIO_WRITE)
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{
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if (runp->aiocb.aio_lio_opcode & 128)
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runp->aiocb.__return_value =
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TEMP_FAILURE_RETRY (__pwrite64 (fildes,
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(const void *) runp->aiocb64.aio_buf,
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runp->aiocb64.aio_nbytes,
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runp->aiocb64.aio_offset));
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else
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runp->aiocb.__return_value =
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TEMP_FAILURE_RETRY (__pwrite (fildes,
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(const void *) runp->aiocb.aio_buf,
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runp->aiocb.aio_nbytes,
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runp->aiocb.aio_offset));
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}
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else if (runp->aiocb.aio_lio_opcode == __LIO_DSYNC)
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runp->aiocb.__return_value = TEMP_FAILURE_RETRY (fdatasync (fildes));
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else if (runp->aiocb.aio_lio_opcode == __LIO_SYNC)
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runp->aiocb.__return_value = TEMP_FAILURE_RETRY (fsync (fildes));
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else
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{
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/* This is an invalid opcode. */
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runp->aiocb.__return_value = -1;
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__set_errno (EINVAL);
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}
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if (runp->aiocb.__return_value == -1)
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runp->aiocb.__error_code = errno;
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else
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runp->aiocb.__error_code = 0;
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/* Send the signal to notify about finished processing of the
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request. */
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if (runp->aiocb.aio_sigevent.sigev_notify == SIGEV_THREAD)
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{
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/* We have to start a thread. */
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pthread_t tid;
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pthread_attr_t attr, *pattr;
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pattr = (pthread_attr_t *)
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runp->aiocb.aio_sigevent.sigev_notify_attributes;
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if (pattr == NULL)
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{
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pthread_attr_init (&attr);
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pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
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pattr = &attr;
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}
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if (pthread_create (&tid,
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(pthread_attr_t *)
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runp->aiocb.aio_sigevent.sigev_notify_attributes,
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(void *(*) (void *))
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runp->aiocb.aio_sigevent.sigev_notify_function,
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runp->aiocb.aio_sigevent.sigev_value.sival_ptr)
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< 0)
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{
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/* XXX What shall we do if already an error is set by
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read/write/fsync? */
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runp->aiocb.__error_code = errno;
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runp->aiocb.__return_value = -1;
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}
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}
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else if (runp->aiocb.aio_sigevent.sigev_notify == SIGEV_SIGNAL)
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/* We have to send a signal. */
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if (__aio_sigqueue (runp->aiocb.aio_sigevent.sigev_signo,
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runp->aiocb.aio_sigevent.sigev_value) < 0)
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{
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/* XXX What shall we do if already an error is set by
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read/write/fsync? */
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runp->aiocb.__error_code = errno;
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runp->aiocb.__return_value = -1;
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}
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/* Get the semaphore. */
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sem_wait (&__aio_requests_sema);
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/* Now dequeue the current request. */
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if (runp->aiocb.__next_prio == NULL)
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{
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if (runp->aiocb.__next_fd != NULL)
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runp->aiocb.__next_fd->__last_fd = runp->aiocb.__last_fd;
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if (runp->aiocb.__last_fd != NULL)
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runp->aiocb.__last_fd->__next_fd = runp->aiocb.__next_fd;
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runp = NULL;
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}
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else
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{
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runp->aiocb.__next_prio->__last_fd = runp->aiocb.__last_fd;
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runp->aiocb.__next_prio->__next_fd = runp->aiocb.__next_fd;
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if (runp->aiocb.__next_fd != NULL)
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runp->aiocb.__next_fd->__last_fd = runp->aiocb.__next_prio;
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if (runp->aiocb.__last_fd != NULL)
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runp->aiocb.__last_fd->__next_fd = runp->aiocb.__next_prio;
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runp = (aiocb_union *) runp->aiocb.__next_prio;
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}
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/* Release the semaphore. */
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sem_post (&__aio_requests_sema);
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}
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while (runp != NULL);
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pthread_exit (NULL);
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}
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