/*
* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2006 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) 2013 University of Houston. All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*
* These symbols are in a file by themselves to provide nice linker
* semantics. Since linkers generally pull in symbols by object fules,
* keeping these symbols as the only symbols in this file prevents
* utility programs such as "ompi_info" from having to import entire
* modules just to query their version and parameters
*/
#include "ompi_config.h"
#include "mpi.h"
#include "ompi/mca/sharedfp/sharedfp.h"
#include "ompi/mca/sharedfp/base/base.h"
#include "ompi/mca/sharedfp/lockedfile/sharedfp_lockedfile.h"
/* included so that we can test file locking availability */
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
/*
* *******************************************************************
* ************************ actions structure ************************
* *******************************************************************
*/
/* IMPORTANT: Update here when adding sharedfp component interface functions*/
static mca_sharedfp_base_module_1_0_0_t lockedfile = {
mca_sharedfp_lockedfile_module_init, /* initalise after being selected */
mca_sharedfp_lockedfile_module_finalize, /* close a module on a communicator */
mca_sharedfp_lockedfile_seek,
mca_sharedfp_lockedfile_get_position,
mca_sharedfp_lockedfile_read,
mca_sharedfp_lockedfile_read_ordered,
mca_sharedfp_lockedfile_read_ordered_begin,
mca_sharedfp_lockedfile_read_ordered_end,
mca_sharedfp_lockedfile_iread,
mca_sharedfp_lockedfile_write,
mca_sharedfp_lockedfile_write_ordered,
mca_sharedfp_lockedfile_write_ordered_begin,
mca_sharedfp_lockedfile_write_ordered_end,
mca_sharedfp_lockedfile_iwrite,
mca_sharedfp_lockedfile_file_open,
mca_sharedfp_lockedfile_file_close
};
/*
* *******************************************************************
* ************************* structure ends **************************
* *******************************************************************
*/
int mca_sharedfp_lockedfile_component_init_query(bool enable_progress_threads,
bool enable_mpi_threads)
{
/* Nothing to do */
return OMPI_SUCCESS;
}
struct mca_sharedfp_base_module_1_0_0_t * mca_sharedfp_lockedfile_component_file_query(mca_io_ompio_file_t *fh, int *priority) {
struct flock lock;
int fd, err;
/*char *filename;*/
char filename[256];
int rank;
bool has_file_lock_support=false;
*priority = mca_sharedfp_lockedfile_priority;
/*get the rank of this process*/
rank = ompi_comm_rank ( fh->f_comm);
/*test, and update priority*/
/*
* This test tests to see if fcntl returns success when asked to
* establish a file lock. This test is intended for use on file systems
* such as NFS that may not implement file locks. The locked file algorithm makes use
* of file locks to implement the shared file pointer operations, and will not work
* properly if file locks are not available.
*
* This is a simple test and has at least two limitations:
*
* 1. Some implementations of NFS are known to return success for
* setting a file lock when in fact no lock has been set. This
* test will not detect such erroneous implementations of NFS
*
* 2. Some implementations will hang (enter and wait indefinitately)
* within the fcntl call. This test will also hang in that case.
* Under normal conditions, this test should only take a few seconds to
* run.
*
* The test prints a message showing the success or failure of
* setting the file lock if PRINT_TAG is set to true in sharedfp.h.
* It also sets the priority to a non-zero value on success and
* returns NULL on failure. If there is a failure, the system routine
* strerror is interogated in order to print the reason.
*/
/* Set the filename. */
/*data filename created by appending .locktest.$rank to the original filename*/
sprintf(filename,"%s%s%d",fh->f_filename,".locktest.",rank);
lock.l_type = F_WRLCK;
lock.l_start = 0;
lock.l_whence = SEEK_SET;
lock.l_len = 100;
lock.l_pid = getpid();
fd = open(filename, O_RDWR | O_CREAT, 0644);
if ( -1 == fd ){
opal_output(ompi_sharedfp_base_framework.framework_output,
"mca_sharedfp_lockedfile_component_file_query: error opening file %s %s", filename, strerror(errno));
has_file_lock_support=false;
}
else{
err = fcntl(fd, F_SETLKW, &lock);
opal_output(ompi_sharedfp_base_framework.framework_output,
"mca_sharedfp_lockedfile_component_file_query: returned err=%d, for fd=%d\n",err,fd);
if (err) {
opal_output(ompi_sharedfp_base_framework.framework_output,
"mca_sharedfp_lockedfile_component_file_query: Failed to set a file lock on %s %s\n", filename, strerror(errno) );
opal_output(ompi_sharedfp_base_framework.framework_output,
"err=%d, errno=%d, EOPNOTSUPP=%d, EINVAL=%d, ENOSYS=%d, EACCES=%d, EAGAIN=%d, EBADF=%d\n",
err, errno, EOPNOTSUPP, EINVAL, ENOSYS, EACCES, EAGAIN, EBADF);
if (errno == EACCES || errno == EAGAIN) {
opal_output(ompi_sharedfp_base_framework.framework_output,
"errno=EACCES || EAGAIN, Already locked by another process\n");
}
}
else {
opal_output(ompi_sharedfp_base_framework.framework_output,
"mca_sharedfp_lockedfile_component_file_query: fcntl claims success in setting a file lock on %s\n", filename );
has_file_lock_support=true;
}
/* printf("err = %d, errno = %d\n", err, errno); */
close(fd);
unlink( filename );
}
/**priority=100;*/
if(has_file_lock_support){
return &lockedfile;
}
*priority = 0;
/*module can not run!, return NULL to indicate that we are unable to run*/
opal_output(ompi_sharedfp_base_framework.framework_output,
"mca_sharedfp_lockedfile_component_file_query: Can not run!, file locking not supported\n");
return NULL;
}
int mca_sharedfp_lockedfile_component_file_unquery (mca_io_ompio_file_t *file)
{
/* This function might be needed for some purposes later. for now it
* does not have anything to do since there are no steps which need
* to be undone if this module is not selected */
return OMPI_SUCCESS;
}
int mca_sharedfp_lockedfile_module_init (mca_io_ompio_file_t *file)
{
return OMPI_SUCCESS;
}
int mca_sharedfp_lockedfile_module_finalize (mca_io_ompio_file_t *file)
{
return OMPI_SUCCESS;
}