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/*
* Copyright (c) 2004-2008 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2005 The University of Tennessee and The University
* of Tennessee Research Foundation. All rights
* reserved.
* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2007-2010 Cisco Systems, Inc. All rights reserved.
* Copyright (c) 2008 Sun Microsystems, Inc. All rights reserved.
* Copyright (c) 2010-2011 Los Alamos National Security, LLC.
* All rights reserved.
* Copyright (c) 2011 NVIDIA Corporation. All rights reserved.
*
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "opal_config.h"
#include <errno.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif /* HAVE_FCNTL_H */
#ifdef HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif /* HAVE_SYS_MMAN_H */
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif /* HAVE_SYS_TYPES_H */
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif /* HAVE_NETDB_H */
#include "opal/util/output.h"
#include "opal/util/show_help.h"
#include "opal/mca/shmem/base/base.h"
#include "opal/mca/shmem/shmem.h"
#include "shmem_posix.h"
#include "shmem_posix_common_utils.h"
/* ////////////////////////////////////////////////////////////////////////// */
int
shmem_posix_shm_open(char *posix_file_name_buff, size_t size)
{
int attempt = 0, fd = -1;
/* workaround for simultaneous posix shm_opens on the same node (e.g.
* multiple Open MPI jobs sharing a node). name collision during component
* runtime will happen, so protect against it by trying a few times.
*/
do {
/* format: /open_mpi.nnnn
* see comment in shmem_posix.h that explains why we chose to do things
* this way.
*/
snprintf(posix_file_name_buff, size, "%s%04d",
OPAL_SHMEM_POSIX_FILE_NAME_PREFIX, attempt++);
/* the check for the existence of the object and its creation if it
* does not exist are performed atomically.
*/
if (-1 == (fd = shm_open(posix_file_name_buff,
O_CREAT | O_EXCL | O_RDWR, 0600))) {
int err = errno;
/* the object already exists, so try again with a new name */
if (EEXIST == err) {
continue;
}
/* a "real" error occurred. fd is already set to -1, so get out
* of here. we can't be selected :-(.
*/
else {
char hn[MAXHOSTNAMELEN];
gethostname(hn, MAXHOSTNAMELEN - 1);
hn[MAXHOSTNAMELEN - 1] = '\0';
opal_output_verbose(10, opal_shmem_base_output,
"shmem_posix_shm_open: disqualifying posix because "
"shm_open(2) failed with error: %s (errno %d)\n",
strerror(err), err);
break;
}
}
/* we found an available file name */
else {
break;
}
} while (attempt < OPAL_SHMEM_POSIX_MAX_ATTEMPTS);
/* if we didn't find a name, let the user know that we tried and failed */
if (attempt >= OPAL_SHMEM_POSIX_MAX_ATTEMPTS) {
opal_output(0, "shmem: posix: file name search - max attempts exceeded."
"cannot continue with posix.\n");
}
return fd;
}
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