First commit for modularing darshan runtime

New darshan-core source files which intercept MPI init/finalize,
initialize darshan job information, and first attempt at a POSIX
module.

darshan-runtime/Makefile.in

-all: lib/libdarshan-posix.a lib/libdarshan-mpi-io.a lib/libdarshan-stubs.a
+all: lib/libdarshan-core.a
+#all: lib/libdarshan-posix.a lib/libdarshan-mpi-io.a lib/libdarshan-stubs.a
 
 DESTDIR =
 srcdir = @srcdir@
@@ -18,14 +19,14 @@ DISABLE_LDPRELOAD = @DISABLE_LDPRELOAD@
 DARSHAN_LOG_FORMAT = $(srcdir)/../darshan-log-format.h
 DARSHAN_VERSION = @DARSHAN_VERSION@
 
-ifndef DISABLE_LDPRELOAD
-all: lib/libdarshan.so 
-endif
+#ifndef DISABLE_LDPRELOAD
+#all: lib/libdarshan.so 
+#endif
 
 VPATH = $(srcdir)
 
 CFLAGS = -DDARSHAN_CONFIG_H=\"darshan-runtime-config.h\" -I . -I ../ -I $(srcdir) -I$(srcdir)/../ @CFLAGS@ @CPPFLAGS@ -D_LARGEFILE64_SOURCE 
-
+#
 CFLAGS_SHARED = -DDARSHAN_CONFIG_H=\"darshan-runtime-config.h\" -I . -I$(srcdir) -I$(srcdir)/../ @CFLAGS@ @CPPFLAGS@ -D_LARGEFILE64_SOURCE -shared -fpic -DPIC -DDARSHAN_PRELOAD
 
 LIBS = -lz @LIBBZ2@
@@ -33,89 +34,96 @@ LIBS = -lz @LIBBZ2@
 lib::
 	@mkdir -p $@
 
-lib/darshan-mpi-io.o: lib/darshan-mpi-io.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
+lib/darshan-core.o: lib/darshan-core.c darshan-core.h $(DARSHAN_LOG_FORMAT) | lib
 	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/darshan-mpi-io.po: lib/darshan-mpi-io.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
-	$(CC) $(CFLAGS_SHARED) -c $< -o $@
+#lib/darshan-mpi-io.o: lib/darshan-mpi-io.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/darshan-mpi-init-finalize.o: lib/darshan-mpi-init-finalize.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
-	$(CC) $(CFLAGS) -c $< -o $@
+#lib/darshan-mpi-io.po: lib/darshan-mpi-io.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS_SHARED) -c $< -o $@
 
-lib/darshan-mpi-init-finalize.po: lib/darshan-mpi-init-finalize.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
-	$(CC) $(CFLAGS_SHARED) -c $< -o $@
+#lib/darshan-mpi-init-finalize.o: lib/darshan-mpi-init-finalize.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/darshan-pnetcdf-stubs.o: lib/darshan-pnetcdf-stubs.c darshan.h $(DARSHAN_LOG_FORMAT) | lib 
-	$(CC) $(CFLAGS) -c $< -o $@
+#lib/darshan-mpi-init-finalize.po: lib/darshan-mpi-init-finalize.c darshan.h darshan-dynamic.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS_SHARED) -c $< -o $@
 
-lib/darshan-pnetcdf.o: lib/darshan-pnetcdf.c darshan.h $(DARSHAN_LOG_FORMAT) | lib 
-	$(CC) $(CFLAGS) -c $< -o $@
+#lib/darshan-pnetcdf-stubs.o: lib/darshan-pnetcdf-stubs.c darshan.h $(DARSHAN_LOG_FORMAT) | lib 
+#	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/darshan-pnetcdf.po: lib/darshan-pnetcdf.c darshan.h $(DARSHAN_LOG_FORMAT) | lib 
-	$(CC) $(CFLAGS_SHARED) -c $< -o $@
+#lib/darshan-pnetcdf.o: lib/darshan-pnetcdf.c darshan.h $(DARSHAN_LOG_FORMAT) | lib 
+#	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/darshan-hdf5.o: lib/darshan-hdf5.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
-	$(CC) $(CFLAGS) -c $< -o $@
+#lib/darshan-pnetcdf.po: lib/darshan-pnetcdf.c darshan.h $(DARSHAN_LOG_FORMAT) | lib 
+#	$(CC) $(CFLAGS_SHARED) -c $< -o $@
 
-lib/darshan-hdf5-stubs.o: lib/darshan-hdf5-stubs.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
-	$(CC) $(CFLAGS) -c $< -o $@
+#lib/darshan-hdf5.o: lib/darshan-hdf5.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS) -c $< -o $@
+
+#lib/darshan-hdf5-stubs.o: lib/darshan-hdf5-stubs.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/darshan-hdf5.po: lib/darshan-hdf5.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
-	$(CC) $(CFLAGS_SHARED) -c $< -o $@
+#lib/darshan-hdf5.po: lib/darshan-hdf5.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS_SHARED) -c $< -o $@
 
 lib/darshan-posix.o: lib/darshan-posix.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
 	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/darshan-posix.po: lib/darshan-posix.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
-	$(CC) $(CFLAGS_SHARED) -c $< -o $@
+#lib/darshan-posix.po: lib/darshan-posix.c darshan.h $(DARSHAN_LOG_FORMAT) | lib
+#	$(CC) $(CFLAGS_SHARED) -c $< -o $@
 
 lib/lookup3.o: lib/lookup3.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/lookup3.po: lib/lookup3.c
-	$(CC) $(CFLAGS_SHARED) -c $< -o $@
+#lib/lookup3.po: lib/lookup3.c
+#	$(CC) $(CFLAGS_SHARED) -c $< -o $@
 
 lib/lookup8.o: lib/lookup8.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
-lib/lookup8.po: lib/lookup8.c
-	$(CC) $(CFLAGS_SHARED) -c $< -o $@
+#lib/lookup8.po: lib/lookup8.c
+#	$(CC) $(CFLAGS_SHARED) -c $< -o $@
 
-%.i: %.c
-	$(CC) -E $(CFLAGS) -c $< -o $@
+#%.i: %.c
+#	$(CC) -E $(CFLAGS) -c $< -o $@
 
-lib/libdarshan-mpi-io.a: lib/darshan-mpi-io.o lib/darshan-mpi-init-finalize.o lib/darshan-pnetcdf.o lib/darshan-hdf5.o
+lib/libdarshan-core.a: lib/darshan-core.o lib/lookup3.o lib/lookup8.o lib/darshan-posix.o
 	ar rcs $@ $^
 
-lib/libdarshan-stubs.a: lib/darshan-pnetcdf-stubs.o lib/darshan-hdf5-stubs.o
-	ar rcs $@ $^
+#lib/libdarshan-mpi-io.a: lib/darshan-mpi-io.o lib/darshan-mpi-init-finalize.o lib/darshan-pnetcdf.o lib/darshan-hdf5.o
+#	ar rcs $@ $^
 
-lib/libdarshan-posix.a: lib/darshan-posix.o lib/lookup3.o lib/lookup8.o 
-	ar rcs $@ $^
+#lib/libdarshan-stubs.a: lib/darshan-pnetcdf-stubs.o lib/darshan-hdf5-stubs.o
+#	ar rcs $@ $^
+
+#lib/libdarshan-posix.a: lib/darshan-posix.o lib/lookup3.o lib/lookup8.o 
+#	ar rcs $@ $^
 
-lib/libdarshan.so: lib/darshan-mpi-io.po lib/darshan-mpi-init-finalize.po lib/darshan-pnetcdf.po lib/darshan-hdf5.po lib/darshan-posix.po lib/lookup3.po lib/lookup8.po
-	$(CC) $(CFLAGS_SHARED) $(LDFLAGS) -o $@ $^ -lpthread -lrt -lz -ldl
+#lib/libdarshan.so: lib/darshan-mpi-io.po lib/darshan-mpi-init-finalize.po lib/darshan-pnetcdf.po lib/darshan-hdf5.po lib/darshan-posix.po lib/lookup3.po lib/lookup8.po
+#	$(CC) $(CFLAGS_SHARED) $(LDFLAGS) -o $@ $^ -lpthread -lrt -lz -ldl
 
 install:: all
 	install -d $(libdir)
-	install -m 755 lib/libdarshan-posix.a $(libdir)
-	install -m 755 lib/libdarshan-mpi-io.a $(libdir)
-	install -m 755 lib/libdarshan-stubs.a $(libdir)
-ifndef DISABLE_LDPRELOAD
-	install -m 755 lib/libdarshan.so $(libdir)
-endif
+	install -m 755 lib/libdarshan-core.a $(libdir)
+#	install -m 755 lib/libdarshan-posix.a $(libdir)
+#	install -m 755 lib/libdarshan-mpi-io.a $(libdir)
+#	install -m 755 lib/libdarshan-stubs.a $(libdir)
+#ifndef DISABLE_LDPRELOAD
+#	install -m 755 lib/libdarshan.so $(libdir)
+#endif
 	install -d $(bindir)
-	install -m 755 darshan-mk-log-dirs.pl $(bindir)
+#	install -m 755 darshan-mk-log-dirs.pl $(bindir)
 	install -m 755 darshan-gen-cc.pl $(bindir)
-	install -m 755 darshan-gen-cxx.pl $(bindir)
-	install -m 755 darshan-gen-fortran.pl $(bindir)
-	install -m 755 darshan-config $(bindir)
-	install -d $(datarootdir)/craype-1.x/modulefiles/darshan
-	install -m 755 share/craype-1.x/darshan-module $(datarootdir)/craype-1.x/modulefiles/darshan/$(DARSHAN_VERSION)
-	install -d $(datarootdir)/craype-2.x/modulefiles/darshan
-	install -m 755 share/craype-2.x/darshan-module $(datarootdir)/craype-2.x/modulefiles/darshan/$(DARSHAN_VERSION)
-	install -d $(libdir)/pkgconfig
-	install -m 644 lib/pkgconfig/darshan-runtime.pc $(libdir)/pkgconfig/darshan-runtime.pc
+#	install -m 755 darshan-gen-cxx.pl $(bindir)
+#	install -m 755 darshan-gen-fortran.pl $(bindir)
+#	install -m 755 darshan-config $(bindir)
+#	install -d $(datarootdir)/craype-1.x/modulefiles/darshan
+#	install -m 755 share/craype-1.x/darshan-module $(datarootdir)/craype-1.x/modulefiles/darshan/$(DARSHAN_VERSION)
+#	install -d $(datarootdir)/craype-2.x/modulefiles/darshan
+#	install -m 755 share/craype-2.x/darshan-module $(datarootdir)/craype-2.x/modulefiles/darshan/$(DARSHAN_VERSION)
+#	install -d $(libdir)/pkgconfig
+#	install -m 644 lib/pkgconfig/darshan-runtime.pc $(libdir)/pkgconfig/darshan-runtime.pc
 
 clean::
 	rm -f *.o *.a lib/*.o lib/*.po lib/*.a lib/*.so 

darshan-runtime/darshan-config.in

@@ -10,9 +10,10 @@ DARSHAN_LD_FLAGS="@LDFLAGS@"
 #   final one is necessary to give the linker a change to resolve indirect
 #   dependencies on PnetCDF and HDF5 symbols (if the app used a library which 
 #   in turn used one of those HLLs).
-PRE_LD_FLAGS="-L$DARSHAN_LIB_PATH $DARSHAN_LD_FLAGS -ldarshan-mpi-io -lz $CP_WRAPPERS"
-POST_LD_FLAGS="-L$DARSHAN_LIB_PATH -ldarshan-posix -ldarshan-mpi-io -lz -lrt -lpthread"
-
+PRE_LD_FLAGS="-L$DARSHAN_LIB_PATH $DARSHAN_LD_FLAGS -ldarshan-core -lz $CP_WRAPPERS"
+POST_LD_FLAGS="-L$DARSHAN_LIB_PATH -ldarshan-core -lz -lrt -lpthread"
+#PRE_LD_FLAGS="-L$DARSHAN_LIB_PATH $DARSHAN_LD_FLAGS -ldarshan-mpi-io -lz $CP_WRAPPERS"
+#POST_LD_FLAGS="-L$DARSHAN_LIB_PATH -ldarshan-posix -ldarshan-mpi-io -lz -lrt -lpthread"
 
 usage="\
 Usage: darshan-config [--pre-ld-flags] [--post-ld-flags]"

darshan-runtime/darshan-core.h

+/*
+ *  (C) 2014 by Argonne National Laboratory.
+ *      See COPYRIGHT in top-level directory.
+ */
+
+#ifndef __DARSHAN_CORE_H
+#define __DARSHAN_CORE_H
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <stdint.h>
+
+#define DARSHAN_MPI_CALL(func) func
+
+typedef uint64_t darshan_file_id;
+
+struct darshan_module_funcs
+{
+    void (*prepare_for_shutdown)(void);
+    void (*get_output_data)(void **, int);
+};
+
+struct darshan_module
+{
+    char *name;
+    struct darshan_module_funcs mod_funcs;
+};
+
+void darshan_core_register_module(
+    char *name,
+    struct darshan_module_funcs *funcs,
+    int *runtime_mem_limit);
+
+void darshan_core_lookup_id(
+    void *name,
+    int len,
+    int printable_flag,
+    darshan_file_id *id);
+
+#endif /* __DARSHAN_CORE_H */

darshan-runtime/darshan.h

@@ -225,16 +225,11 @@ enum cp_counter_type
  * http://publib.boulder.ibm.com/infocenter/compbgpl/v9v111/index.jsp?topic=/com.ibm.bg9111.doc/bgusing/data_alignment.htm
  */
 
-extern struct darshan_job_runtime* darshan_global_job;
-
-void darshan_initialize(int argc, char** argv, int nprocs, int rank);
 void darshan_finalize(struct darshan_job_runtime* job);
 void darshan_condense(void);
-void darshan_shutdown(int timing_flag);
 void darshan_walk_file_accesses(struct darshan_job_runtime* final_job);
 double darshan_wtime(void);
 void darshan_mnt_id_from_path(const char* path, int64_t* device_id, int64_t* block_size);
-char* darshan_get_exe_and_mounts(struct darshan_job_runtime* final_job);
 void darshan_mpi_initialize(int *argc, char ***argv);
 
 uint32_t darshan_hashlittle(const void *key, size_t length, uint32_t initval);

darshan-runtime/lib/darshan-core.c

+/*
+ *  (C) 2009 by Argonne National Laboratory.
+ *      See COPYRIGHT in top-level directory.
+ */
+
+#include "darshan-runtime-config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#ifdef HAVE_MNTENT_H
+#include <mntent.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/vfs.h>
+
+#include <mpi.h>
+#include "darshan.h"
+#include "darshan-core.h"
+
+extern char* __progname_full;
+
+static void darshan_initialize(int *argc, char ***argv);
+static void darshan_shutdown(void);
+static char *darshan_get_exe_and_mounts(int rank);
+static void darshan_get_exe_and_mounts_root(char* trailing_data, int space_left);
+
+static struct darshan_job_runtime *darshan_global_job = NULL;
+static int darshan_mem_alignment = 1;
+
+#define CP_MAX_MNTS 64
+#define CP_MAX_MNT_PATH 256
+#define CP_MAX_MNT_TYPE 32
+struct mnt_data
+{
+    int64_t hash;
+    int64_t block_size;
+    char path[CP_MAX_MNT_PATH];
+    char type[CP_MAX_MNT_TYPE];
+};
+static struct mnt_data mnt_data_array[CP_MAX_MNTS];
+static int mnt_data_count = 0;
+
+/* intercept MPI initialize and finalize to initialize darshan */
+int MPI_Init(int *argc, char ***argv)
+{
+    int ret;
+
+    ret = DARSHAN_MPI_CALL(PMPI_Init)(argc, argv);
+    if(ret != MPI_SUCCESS)
+    {
+        return(ret);
+    }
+
+    darshan_initialize(argc, argv);
+
+    return(ret);
+}
+
+int MPI_Init_thread (int *argc, char ***argv, int required, int *provided)
+{
+    int ret;
+
+    ret = DARSHAN_MPI_CALL(PMPI_Init_thread)(argc, argv, required, provided);
+    if (ret != MPI_SUCCESS)
+    {
+        return(ret);
+    }
+
+    darshan_initialize(argc, argv);
+
+    return(ret);
+}
+
+int MPI_Finalize(void)
+{
+    int ret;
+
+    darshan_shutdown();
+
+    ret = DARSHAN_MPI_CALL(PMPI_Finalize)();
+    return(ret);
+}
+
+static void darshan_initialize(int *argc, char ***argv)
+{
+    int i;
+    int nprocs;
+    int rank;
+    int internal_timing_flag = 0;
+    double init_start, init_time, init_max;
+    char *mem_align;
+    char* truncate_string = "<TRUNCATED>";
+    int truncate_offset;
+    int chars_left = 0;
+    int ret;
+    int tmpval;
+
+    DARSHAN_MPI_CALL(PMPI_Comm_size)(MPI_COMM_WORLD, &nprocs);
+    DARSHAN_MPI_CALL(PMPI_Comm_rank)(MPI_COMM_WORLD, &rank);
+
+    if(getenv("DARSHAN_INTERNAL_TIMING"))
+        internal_timing_flag = 1;
+
+    if (internal_timing_flag)
+        init_start = DARSHAN_MPI_CALL(PMPI_Wtime)();
+
+    /* setup darshan runtime if darshan is enabled and hasn't been initialized already */
+    if (!getenv("DARSHAN_DISABLE") && !darshan_global_job)
+    {
+        #if (__CP_MEM_ALIGNMENT < 1)
+            #error Darshan must be configured with a positive value for --with-mem-align
+        #endif
+        mem_align = getenv("DARSHAN_MEMALIGN");
+        if (mem_align)
+        {
+            ret = sscanf(mem_align, "%d", &tmpval);
+            /* silently ignore if the env variable is set poorly */
+            if(ret == 1 && tmpval > 0)
+            {
+                darshan_mem_alignment = tmpval;
+            }
+        }
+        else
+        {
+            darshan_mem_alignment == __CP_MEM_ALIGNMENT;
+        }
+
+        /* avoid floating point errors on faulty input */
+        if (darshan_mem_alignment < 1)
+        {
+            darshan_mem_alignment = 1;
+        }
+
+        /* allocate structure to track darshan_global_job information */
+        darshan_global_job = malloc(sizeof(*darshan_global_job));
+        if (darshan_global_job)
+        {
+            memset(darshan_global_job, 0, sizeof(*darshan_global_job));
+
+            if (getenv("DARSHAN_DISABLE_TIMING"))
+            {
+                darshan_global_job->flags |= CP_FLAG_NOTIMING;
+            }
+
+            /* set up file records */
+            for(i=0; i<CP_MAX_FILES; i++)
+            {
+                darshan_global_job->file_runtime_array[i].log_file =
+                    &darshan_global_job->file_array[i];
+            }
+
+            strcpy(darshan_global_job->log_job.version_string, CP_VERSION);
+            darshan_global_job->log_job.magic_nr = CP_MAGIC_NR;
+            darshan_global_job->log_job.uid = getuid();
+            darshan_global_job->log_job.start_time = time(NULL);
+            darshan_global_job->log_job.nprocs = nprocs;
+            darshan_global_job->wtime_offset = DARSHAN_MPI_CALL(PMPI_Wtime)();
+
+            /* record exe and arguments */
+            for(i=0; i<(*argc); i++)
+            {
+                chars_left = CP_EXE_LEN-strlen(darshan_global_job->exe);
+                strncat(darshan_global_job->exe, *(argv[i]), chars_left);
+                if(i < ((*argc)-1))
+                {
+                    chars_left = CP_EXE_LEN-strlen(darshan_global_job->exe);
+                    strncat(darshan_global_job->exe, " ", chars_left);
+                }
+            }
+
+            /* if we don't see any arguments, then use glibc symbol to get
+             * program name at least (this happens in fortran)
+             */
+            if(argc == 0)
+            {
+                chars_left = CP_EXE_LEN-strlen(darshan_global_job->exe);
+                strncat(darshan_global_job->exe, __progname_full, chars_left);
+                chars_left = CP_EXE_LEN-strlen(darshan_global_job->exe);
+                strncat(darshan_global_job->exe, " <unknown args>", chars_left);
+            }
+
+            if(chars_left == 0)
+            {
+                /* we ran out of room; mark that string was truncated */
+                truncate_offset = CP_EXE_LEN - strlen(truncate_string);
+                sprintf(&darshan_global_job->exe[truncate_offset], "%s",
+                    truncate_string);
+            }
+
+            /* collect information about command line and 
+             * mounted file systems 
+             */
+            darshan_global_job->trailing_data = darshan_get_exe_and_mounts(rank);
+        }
+    }
+
+    if(internal_timing_flag)
+    {
+        init_time = DARSHAN_MPI_CALL(PMPI_Wtime)() - init_start;
+        DARSHAN_MPI_CALL(PMPI_Reduce)(&init_time, &init_max, 1,
+            MPI_DOUBLE, MPI_MAX, 0, MPI_COMM_WORLD);
+        if(rank == 0)
+        {
+            printf("#darshan:<op>\t<nprocs>\t<time>\n");
+            printf("darshan:init\t%d\t%f\n", nprocs, init_max);
+        }
+    }
+
+    return;
+}
+
+static void darshan_shutdown()
+{
+    int internal_timing_flag = 0;
+
+    if(getenv("DARSHAN_INTERNAL_TIMING"))
+        internal_timing_flag = 1;
+
+    printf("darshan SHUTDOWN\n");
+
+    return;
+}
+
+static int mnt_data_cmp(const void* a, const void* b)
+{
+    const struct mnt_data *d_a = (const struct mnt_data*)a;
+    const struct mnt_data *d_b = (const struct mnt_data*)b;
+
+    if(strlen(d_a->path) > strlen(d_b->path))
+        return(-1);
+    else if(strlen(d_a->path) < strlen(d_b->path))
+        return(1);
+    else
+        return(0);
+}
+
+/* adds an entry to table of mounted file systems */
+static void add_entry(char* trailing_data, int* space_left, struct mntent *entry)
+{
+    int ret;
+    char tmp_mnt[256];
+    struct statfs statfsbuf;
+
+    strncpy(mnt_data_array[mnt_data_count].path, entry->mnt_dir,
+        CP_MAX_MNT_PATH-1);
+    strncpy(mnt_data_array[mnt_data_count].type, entry->mnt_type,
+        CP_MAX_MNT_TYPE-1);
+    mnt_data_array[mnt_data_count].hash =
+        darshan_hash((void*)mnt_data_array[mnt_data_count].path,
+        strlen(mnt_data_array[mnt_data_count].path), 0);
+    /* NOTE: we now try to detect the preferred block size for each file 
+     * system using fstatfs().  On Lustre we assume a size of 1 MiB 
+     * because fstatfs() reports 4 KiB. 
+     */
+#ifndef LL_SUPER_MAGIC
+#define LL_SUPER_MAGIC 0x0BD00BD0
+#endif
+    ret = statfs(entry->mnt_dir, &statfsbuf);
+    if(ret == 0 && statfsbuf.f_type != LL_SUPER_MAGIC)
+        mnt_data_array[mnt_data_count].block_size = statfsbuf.f_bsize;
+    else if(ret == 0 && statfsbuf.f_type == LL_SUPER_MAGIC)
+        mnt_data_array[mnt_data_count].block_size = 1024*1024;
+    else
+        mnt_data_array[mnt_data_count].block_size = 4096;
+
+    /* store mount information for use in header of darshan log */
+    ret = snprintf(tmp_mnt, 256, "\n%" PRId64 "\t%s\t%s",
+        mnt_data_array[mnt_data_count].hash,
+        entry->mnt_type, entry->mnt_dir);
+    if(ret < 256 && strlen(tmp_mnt) <= (*space_left))
+    {
+        strcat(trailing_data, tmp_mnt);
+        (*space_left) -= strlen(tmp_mnt);
+    }
+
+    mnt_data_count++;
+    return;
+}
+
+/* darshan_get_exe_and_mounts_root()
+ *
+ * collects command line and list of mounted file systems into a string that
+ * will be stored with the job header
+ */
+static void darshan_get_exe_and_mounts_root(char* trailing_data, int space_left)
+{
+    FILE* tab;
+    struct mntent *entry;
+    char* exclude;
+    int tmp_index = 0;
+    int skip = 0;
+
+    /* skip these fs types */
+    static char* fs_exclusions[] = {
+        "tmpfs",
+        "proc",
+        "sysfs",
+        "devpts",
+        "binfmt_misc",
+        "fusectl",
+        "debugfs",
+        "securityfs",
+        "nfsd",
+        "none",
+        "rpc_pipefs",
+    "hugetlbfs",
+    "cgroup",
+        NULL
+    };
+
+    /* length of exe has already been safety checked in darshan-posix.c */
+    strcat(trailing_data, darshan_global_job->exe);
+    space_left = CP_EXE_LEN - strlen(trailing_data);
+
+    /* we make two passes through mounted file systems; in the first pass we
+     * grab any non-nfs mount points, then on the second pass we grab nfs
+     * mount points
+     */
+
+    tab = setmntent("/etc/mtab", "r");
+    if(!tab)
+        return;
+    /* loop through list of mounted file systems */
+    while(mnt_data_count<CP_MAX_MNTS && (entry = getmntent(tab)) != NULL)
+    {
+        /* filter out excluded fs types */
+        tmp_index = 0;
+        skip = 0;
+        while((exclude = fs_exclusions[tmp_index]))
+        {
+            if(!(strcmp(exclude, entry->mnt_type)))
+            {
+                skip =1;
+                break;
+            }
+            tmp_index++;
+        }
+
+        if(skip || (strcmp(entry->mnt_type, "nfs") == 0))
+            continue;
+
+        add_entry(trailing_data, &space_left, entry);
+    }
+    endmntent(tab);
+
+    tab = setmntent("/etc/mtab", "r");
+    if(!tab)
+        return;
+    /* loop through list of mounted file systems */
+    while(mnt_data_count<CP_MAX_MNTS && (entry = getmntent(tab)) != NULL)
+    {
+        if(strcmp(entry->mnt_type, "nfs") != 0)
+            continue;
+
+        add_entry(trailing_data, &space_left, entry);
+    }
+    endmntent(tab);
+
+    /* Sort mount points in order of longest path to shortest path.  This is
+     * necessary so that if we try to match file paths to mount points later
+     * we don't match on "/" every time.
+     */
+    qsort(mnt_data_array, mnt_data_count, sizeof(mnt_data_array[0]), mnt_data_cmp);
+    return;
+}
+
+/* darshan_get_exe_and_mounts()
+ *
+ * collects command line and list of mounted file systems into a string that
+ * will be stored with the job header
+ */