Handle certain empty subfiling environment variables

src/H5FDsubfiling/H5FDioc.c

@@ -224,7 +224,7 @@ H5FD_ioc_init(void)
 
         /* Check if IOC VFD has been loaded dynamically */
         env_var = getenv(HDF5_DRIVER);
-        if (env_var && !strcmp(env_var, H5FD_IOC_NAME)) {
+        if (env_var && strlen(env_var) > 0 && !strcmp(env_var, H5FD_IOC_NAME)) {
             int mpi_initialized = 0;
             int provided        = 0;
 
@@ -1498,7 +1498,8 @@ H5FD__ioc_del(const char *name, hid_t fapl)
         /* TODO: No support for subfile directory prefix currently */
         /* TODO: Possibly try loading config file prefix from file before deleting */
         snprintf(tmp_filename, PATH_MAX, "%s/" H5FD_SUBFILING_CONFIG_FILENAME_TEMPLATE,
-                 prefix_env ? prefix_env : file_dirname, base_filename, (uint64_t)st.st_ino);
+                 prefix_env && (strlen(prefix_env) > 0) ? prefix_env : file_dirname, base_filename,
+                 (uint64_t)st.st_ino);
 
         if (NULL == (config_file = fopen(tmp_filename, "r"))) {
             if (ENOENT == errno) {

src/H5FDsubfiling/H5subfiling_common.c

@@ -777,7 +777,7 @@ init_subfiling(const char *base_filename, uint64_t file_id, H5FD_subfiling_param
 
     /* Check if a prefix has been set for the configuration file name */
     prefix_env = getenv(H5FD_SUBFILING_CONFIG_FILE_PREFIX);
-    if (prefix_env) {
+    if (prefix_env && (strlen(prefix_env) > 0)) {
         if (NULL == (new_context->config_file_prefix = strdup(prefix_env)))
             H5_SUBFILING_GOTO_ERROR(H5E_VFL, H5E_CANTCOPY, FAIL, "couldn't copy config file prefix string");
     }
@@ -851,7 +851,8 @@ init_subfiling(const char *base_filename, uint64_t file_id, H5FD_subfiling_param
         char *env_value = NULL;
 
         /* Check for a subfiling stripe size setting from the environment */
-        if ((env_value = getenv(H5FD_SUBFILING_STRIPE_SIZE))) {
+        env_value = getenv(H5FD_SUBFILING_STRIPE_SIZE);
+        if (env_value && (strlen(env_value) > 0)) {
             long long stripe_size = -1;
 
             errno = 0;
@@ -981,7 +982,8 @@ init_app_topology(int64_t sf_context_id, H5FD_subfiling_params_t *subfiling_conf
         case SELECT_IOC_ONE_PER_NODE: {
             if (comm_size > 1) {
                 /* Check for an IOC-per-node value set in the environment */
-                if ((env_value = getenv(H5FD_SUBFILING_IOC_PER_NODE))) {
+                env_value = getenv(H5FD_SUBFILING_IOC_PER_NODE);
+                if (env_value && (strlen(env_value) > 0)) {
                     errno          = 0;
                     ioc_select_val = strtol(env_value, NULL, 0);
                     if ((ERANGE == errno)) {
@@ -1186,7 +1188,7 @@ get_ioc_selection_criteria_from_env(H5FD_subfiling_ioc_select_t *ioc_selection_t
 
     *ioc_sel_info_str = NULL;
 
-    if (env_value) {
+    if (env_value && (strlen(env_value) > 0)) {
         /*
          * Parse I/O Concentrator selection strategy criteria as
          * either a single value or two colon-separated values of
@@ -1821,7 +1823,8 @@ init_subfiling_context(subfiling_context_t *sf_context, const char *base_filenam
                                 "couldn't allocate space for subfiling filename");
 
     /* Check for a subfile name prefix setting in the environment */
-    if ((env_value = getenv(H5FD_SUBFILING_SUBFILE_PREFIX))) {
+    env_value = getenv(H5FD_SUBFILING_SUBFILE_PREFIX);
+    if (env_value && (strlen(env_value) > 0)) {
         if (NULL == (sf_context->subfile_prefix = strdup(env_value)))
             H5_SUBFILING_GOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "couldn't copy subfile prefix value");
     }

testpar/t_subfiling_vfd.c

@@ -3237,6 +3237,44 @@ main(int argc, char **argv)
         SKIPPED();
 #endif
 
+    if (MAINPROCESS)
+        printf("\nRe-running tests with environment variables set to the empty string\n");
+
+    HDsetenv("H5FD_SUBFILING_SUBFILE_PREFIX", "", 1);
+    HDsetenv("H5FD_SUBFILING_IOC_SELECTION_CRITERIA", "", 1);
+    HDsetenv("H5FD_SUBFILING_IOC_PER_NODE", "", 1);
+    HDsetenv("H5FD_SUBFILING_STRIPE_SIZE", "", 1);
+    HDsetenv("H5FD_SUBFILING_CONFIG_FILE_PREFIX", "", 1);
+
+    /* Grab values from environment variables if set */
+    parse_subfiling_env_vars();
+
+    /*
+     * Assume that we use the "one IOC per node" selection
+     * strategy by default, with a possibly modified
+     * number of IOCs per node value
+     */
+    num_iocs_g = (ioc_per_node_g > 0) ? (int)ioc_per_node_g * num_nodes_g : num_nodes_g;
+    if (num_iocs_g > mpi_size)
+        num_iocs_g = mpi_size;
+
+    for (size_t i = 0; i < ARRAY_SIZE(tests); i++) {
+        if (MPI_SUCCESS == (mpi_code_g = MPI_Barrier(comm_g))) {
+            (*tests[i])();
+        }
+        else {
+            if (MAINPROCESS)
+                MESG("MPI_Barrier failed");
+            nerrors++;
+        }
+    }
+
+    HDunsetenv("H5FD_SUBFILING_SUBFILE_PREFIX");
+    HDunsetenv("H5FD_SUBFILING_IOC_SELECTION_CRITERIA");
+    HDunsetenv("H5FD_SUBFILING_IOC_PER_NODE");
+    HDunsetenv("H5FD_SUBFILING_STRIPE_SIZE");
+    HDunsetenv("H5FD_SUBFILING_CONFIG_FILE_PREFIX");
+
     if (nerrors)
         goto exit;
 

testpar/t_vfd.c

@@ -6250,6 +6250,46 @@ main(int argc, char **argv)
 
     test_vector_io(mpi_rank, mpi_size);
 
+#ifdef H5_HAVE_SUBFILING_VFD
+
+    if (mpi_rank == 0)
+        printf("\n --- TESTING SUBFILING VFD: environment variables set to empty --- \n");
+
+    HDsetenv("H5FD_SUBFILING_SUBFILE_PREFIX", "", 1);
+    HDsetenv("H5FD_SUBFILING_IOC_SELECTION_CRITERIA", "", 1);
+    HDsetenv("H5FD_SUBFILING_IOC_PER_NODE", "", 1);
+    HDsetenv("H5FD_SUBFILING_STRIPE_SIZE", "", 1);
+    HDsetenv("H5FD_SUBFILING_CONFIG_FILE_PREFIX", "", 1);
+
+    MPI_Barrier(comm);
+
+    if (mpi_rank == 0)
+        printf("\n --- TESTING MPIO VFD: selection I/O --- \n");
+
+    test_selection_io(mpi_rank, mpi_size);
+
+    if (mpi_rank == 0)
+        printf("\n --- TESTING MPIO VFD: vector I/O --- \n");
+
+    if (mpi_size < 2) {
+        if (mpi_rank == 0) {
+            printf("     Need at least 2 processes to run tests for vector I/O.");
+            SKIPPED();
+        }
+        printf("\n");
+        goto finish;
+    }
+
+    test_vector_io(mpi_rank, mpi_size);
+
+    HDunsetenv("H5FD_SUBFILING_SUBFILE_PREFIX");
+    HDunsetenv("H5FD_SUBFILING_IOC_SELECTION_CRITERIA");
+    HDunsetenv("H5FD_SUBFILING_IOC_PER_NODE");
+    HDunsetenv("H5FD_SUBFILING_STRIPE_SIZE");
+    HDunsetenv("H5FD_SUBFILING_CONFIG_FILE_PREFIX");
+
+#endif
+
 finish:
     /* make sure all processes are finished before final report, cleanup
      * and exit.