diff options
Diffstat (limited to 'sysdeps/pthread/lio_listio.c')
| -rw-r--r-- | sysdeps/pthread/lio_listio.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/sysdeps/pthread/lio_listio.c b/sysdeps/pthread/lio_listio.c new file mode 100644 index 0000000000..e1df603fd8 --- /dev/null +++ b/sysdeps/pthread/lio_listio.c @@ -0,0 +1,187 @@ +/* Enqueue and list of read or write requests. + Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <aio.h> +#include <assert.h> +#include <errno.h> +#include <stdlib.h> +#include <unistd.h> + +#include "aio_misc.h" + + +/* We need this special structure to handle asynchronous I/O. */ +struct async_waitlist + { + int counter; + struct sigevent sigev; + struct waitlist list[0]; + }; + + +int +lio_listio (mode, list, nent, sig) + int mode; + struct aiocb *const list[]; + int nent; + struct sigevent *sig; +{ + struct sigevent defsigev; + struct requestlist *requests[nent]; + int cnt; + volatile int total = 0; + int result = 0; + + /* Check arguments. */ + if (mode != LIO_WAIT && mode != LIO_NOWAIT) + { + __set_errno (EINVAL); + return -1; + } + + if (sig == NULL) + { + defsigev.sigev_notify = SIGEV_NONE; + sig = &defsigev; + } + + /* Request the mutex. */ + pthread_mutex_lock (&__aio_requests_mutex); + + /* Now we can enqueue all requests. Since we already acquired the + mutex the enqueue function need not do this. */ + for (cnt = 0; cnt < nent; ++cnt) + if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP) + { + list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE; + requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt], + list[cnt]->aio_lio_opcode); + + if (requests[cnt] != NULL) + /* Successfully enqueued. */ + ++total; + else + /* Signal that we've seen an error. `errno' and the error code + of the aiocb will tell more. */ + result = -1; + } + else + requests[cnt] = NULL; + + if (total == 0) + { + /* We don't have anything to do except signalling if we work + asynchronously. */ + + /* Release the mutex. We do this before raising a signal since the + signal handler might do a `siglongjmp' and then the mutex is + locked forever. */ + pthread_mutex_unlock (&__aio_requests_mutex); + + if (mode == LIO_NOWAIT) + __aio_notify_only (sig, + sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0); + + return result; + } + else if (mode == LIO_WAIT) + { + pthread_cond_t cond = PTHREAD_COND_INITIALIZER; + struct waitlist waitlist[nent]; + int oldstate; + + total = 0; + for (cnt = 0; cnt < nent; ++cnt) + { + assert (requests[cnt] == NULL || list[cnt] != NULL); + + if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP) + { + waitlist[cnt].cond = &cond; + waitlist[cnt].next = requests[cnt]->waiting; + waitlist[cnt].counterp = &total; + waitlist[cnt].sigevp = NULL; + waitlist[cnt].caller_pid = 0; /* Not needed. */ + requests[cnt]->waiting = &waitlist[cnt]; + ++total; + } + } + + /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation + points we must be careful. We added entries to the waiting lists + which we must remove. So defer cancelation for now. */ + pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate); + + while (total > 0) + pthread_cond_wait (&cond, &__aio_requests_mutex); + + /* Now it's time to restore the cancelation state. */ + pthread_setcancelstate (oldstate, NULL); + + /* Release the conditional variable. */ + if (pthread_cond_destroy (&cond) != 0) + /* This must never happen. */ + abort (); + } + else + { + struct async_waitlist *waitlist; + + waitlist = (struct async_waitlist *) + malloc (sizeof (struct async_waitlist) + + (nent * sizeof (struct waitlist))); + + if (waitlist == NULL) + { + __set_errno (EAGAIN); + result = -1; + } + else + { + pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0; + total = 0; + + for (cnt = 0; cnt < nent; ++cnt) + { + assert (requests[cnt] == NULL || list[cnt] != NULL); + + if (requests[cnt] != NULL + && list[cnt]->aio_lio_opcode != LIO_NOP) + { + waitlist->list[cnt].cond = NULL; + waitlist->list[cnt].next = requests[cnt]->waiting; + waitlist->list[cnt].counterp = &waitlist->counter; + waitlist->list[cnt].sigevp = &waitlist->sigev; + waitlist->list[cnt].caller_pid = caller_pid; + requests[cnt]->waiting = &waitlist->list[cnt]; + ++total; + } + } + + waitlist->counter = total; + waitlist->sigev = *sig; + } + } + + /* Release the mutex. */ + pthread_mutex_unlock (&__aio_requests_mutex); + + return result; +} |