ABI Query via dlopen example

Signed-off-by: Joshua Hursey <[email protected]>

.gitignore

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+example/abi-query-dlopen

example/Makefile

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+#
+# Copyright (c) 2022      IBM Corporation.  All rights reserved.
+# $COPYRIGHT$
+#
+# Additional copyrights may follow
+#
+# $HEADER$
+#
+PROGS=abi-query-dlopen
+
+all: $(PROGS)
+
+PMIX_ABI_HEADERS=$(PWD)/../
+
+abi-query-dlopen: abi-query-dlopen.c
+	gcc abi-query-dlopen.c -O0 -g -ldl -I$(PMIX_ABI_HEADERS) -o abi-query-dlopen
+
+run:
+	@echo $(PMIX_ROOT)
+
+clean:
+	rm -f $(PROGS) core.*

example/abi-query-dlopen.c

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+/*
+ * Copyright (c) 2022      IBM Corporation.  All rights reserved.
+ * $COPYRIGHT$
+ *
+ * Additional copyrights may follow
+ *
+ * $HEADER$
+ *
+ * Test PMIx_Query_info outside of init/finalize by asking for a
+ * key (PMIX_QUERY_ABI_VERSION) that is allowed to be accessed
+ * outside of the init/finalize region. Use dlopen to pick up
+ * the PMIx library.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dlfcn.h>
+
+// This is the dlopen friendly header from the pmix-abi
+#include <pmix_fns.h>
+
+// Temporary until it is added to the PMIx Standard
+#define PMIX_QUERY_ABI_VERSION              "pmix.qry.abiversion" 
+
+
+int main(int argc, char **argv) {
+    int rc, i;
+    size_t ninfo, nqueries;
+    pmix_info_t *info = NULL;
+    pmix_query_t *query = NULL;
+    char *pmix_root = NULL;
+    char *pmix_lib = NULL;
+
+    pmix_root = getenv("PMIX_ROOT");
+    if( NULL == pmix_root ) {
+        fprintf(stderr, "Error: The envar PMIX_ROOT must be set to a PMIx implementation installation.\n");
+        exit(1);
+    }
+
+    // append "/lib/libpmix.so\0" = 16 characters
+    pmix_lib = (char*)malloc(sizeof(char) * (strlen(pmix_root) + 17));
+    pmix_lib[0] = '\0';
+    strcat(pmix_lib, pmix_root);
+    strcat(pmix_lib, "/lib/libpmix.so");
+    printf("Using: PMIX_ROOT: \"%s\"\n", pmix_root);
+    printf("Using: PMIX_LIB : \"%s\"\n", pmix_lib);
+
+    /*
+     * dlopen the PMIx library using the PMIX_ROOT as the location
+     */
+    void *lib_handle;
+    lib_handle = dlopen(pmix_lib, RTLD_LAZY | RTLD_LOCAL);
+    if( NULL == lib_handle ) {
+        fprintf(stderr, "Error: Failed to open the library. %s\n", dlerror());
+        exit(1);
+    }
+
+    /*
+     * Find the PMIx_Query_info symbol so we can check the ABI level
+     */
+    pmix_query_info_fn_t query_fn;
+    query_fn = dlsym(lib_handle, "PMIx_Query_info");
+    if( NULL == query_fn ) {
+        fprintf(stderr, "Error: Failed to find the PMIx_Query_info symbol. %s\n", dlerror());
+        exit(1);
+    }
+
+    /*
+     * Perform the query
+     */
+    nqueries = 1;
+
+    PMIX_QUERY_CREATE(query, nqueries);
+    PMIX_ARGV_APPEND(rc, query[0].keys, PMIX_QUERY_ABI_VERSION);
+
+    //rc = PMIx_Query_info(query, nqueries, &info, &ninfo);
+    rc = query_fn(query, nqueries, &info, &ninfo);
+    if (PMIX_SUCCESS != rc ) {
+        fprintf(stderr, "Error: PMIx_Query_info failed: %d\n", rc);
+        return rc;
+    }
+
+    printf("--> Query returned (ninfo %lu)\n", ninfo);
+    for(i = 0; i < ninfo; ++i) {
+        printf("--> KEY: %s\n", info[i].key);
+        if (PMIX_CHECK_KEY(&info[i], PMIX_QUERY_ABI_VERSION)) {
+            printf("----> ABI: String: %s\n",
+                   info[i].value.data.string);
+        }
+    }
+
+    PMIX_INFO_FREE(info, ninfo);
+    PMIX_QUERY_FREE(query, nqueries);
+
+    return 0;
+}