[bpf-next,3/5] tools/libbpf: add test program for loading BPF ELF files

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 83714ca1f22b..f968702f4ef6 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -147,11 +147,11 @@  LIB_FILE := $(addprefix $(OUTPUT),$(LIB_FILE))
 
 CMD_TARGETS = $(LIB_FILE)
 
-TARGETS = $(CMD_TARGETS)
+TARGETS = $(CMD_TARGETS) test_libbpf_open
 
 all: fixdep all_cmd
 
-all_cmd: $(CMD_TARGETS)
+all_cmd: $(TARGETS)
 
 $(BPF_IN): force elfdep bpfdep
 	@(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \
@@ -168,6 +168,9 @@  $(OUTPUT)libbpf.so: $(BPF_IN)
 $(OUTPUT)libbpf.a: $(BPF_IN)
 	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
 
+test_libbpf_open: test_libbpf_open.c $(OUTPUT)libbpf.a
+	$(QUIET_LINK)$(CC) -lelf -Wall $< $(OUTPUT)libbpf.a -o $(OUTPUT)$@
+
 define do_install
 	if [ ! -d '$(DESTDIR_SQ)$2' ]; then		\
 		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2';	\
diff --git a/tools/lib/bpf/test_libbpf_open.c b/tools/lib/bpf/test_libbpf_open.c
new file mode 100644
index 000000000000..8fcd1c076add
--- /dev/null
+++ b/tools/lib/bpf/test_libbpf_open.c
@@ -0,0 +1,150 @@ 
+/* SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2018 Jesper Dangaard Brouer, Red Hat Inc.
+ */
+static const char *__doc__ =
+	"Libbpf test program for loading BPF ELF object files";
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
+#include <bpf/libbpf.h>
+#include <getopt.h>
+
+static const struct option long_options[] = {
+	{"help",	no_argument,		NULL, 'h' },
+	{"debug",	no_argument,		NULL, 'D' },
+	{"quiet",	no_argument,		NULL, 'q' },
+	{0, 0, NULL,  0 }
+};
+
+static void usage(char *argv[])
+{
+	int i;
+
+	printf("\nDOCUMENTATION:\n%s\n\n", __doc__);
+	printf(" Usage: %s (options-see-below) BPF_FILE\n", argv[0]);
+	printf(" Listing options:\n");
+	for (i = 0; long_options[i].name != 0; i++) {
+		printf(" --%-12s", long_options[i].name);
+		printf(" short-option: -%c",
+		       long_options[i].val);
+		printf("\n");
+	}
+	printf("\n");
+}
+
+#define DEFINE_PRINT_FN(name, enabled) \
+static int libbpf_##name(const char *fmt, ...)  	\
+{							\
+        va_list args;					\
+        int ret;					\
+							\
+        va_start(args, fmt);				\
+	if (enabled) {					\
+		fprintf(stderr, "[" #name "] ");	\
+		ret = vfprintf(stderr, fmt, args);	\
+	}						\
+        va_end(args);					\
+        return ret;					\
+}
+DEFINE_PRINT_FN(warning, 1)
+DEFINE_PRINT_FN(info, 1)
+DEFINE_PRINT_FN(debug, 1)
+
+#define EXIT_FAIL_LIBBPF EXIT_FAILURE
+#define EXIT_FAIL_OPTION 2
+
+int test_walk_progs(struct bpf_object *obj, bool verbose)
+{
+	struct bpf_program *prog;
+	int cnt = 0;
+
+	bpf_object__for_each_program(prog, obj) {
+		cnt++;
+		if (verbose)
+			printf("Prog (count:%d) section_name: %s\n", cnt,
+			       bpf_program__title(prog, false));
+	}
+	return 0;
+}
+
+int test_walk_maps(struct bpf_object *obj, bool verbose)
+{
+	struct bpf_map *map;
+	int cnt = 0;
+
+	bpf_map__for_each(map, obj) {
+		cnt++;
+		if (verbose)
+			printf("Map (count:%d) name: %s\n", cnt,
+			       bpf_map__name(map));
+	}
+	return 0;
+}
+
+int test_open_file(char *filename, bool verbose)
+{
+	struct bpf_object *bpfobj = NULL;
+	long err;
+
+	if (verbose)
+		printf("Open BPF ELF-file with libbpf: %s\n", filename);
+
+	/* Load BPF ELF object file and check for errors */
+	bpfobj = bpf_object__open(filename);
+	err = libbpf_get_error(bpfobj);
+	if (err) {
+		char err_buf[128];
+		libbpf_strerror(err, err_buf, sizeof(err_buf));
+		if (verbose)
+			printf("Unable to load eBPF objects in file '%s': %s\n",
+			       filename, err_buf);
+		return EXIT_FAIL_LIBBPF;
+	}
+	test_walk_progs(bpfobj, verbose);
+	test_walk_maps(bpfobj, verbose);
+
+	if (verbose)
+		printf("Close BPF ELF-file with libbpf: %s\n",
+		       bpf_object__name(bpfobj));
+	bpf_object__close(bpfobj);
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	char filename[1024] = { 0 };
+	bool verbose = 1;
+	int longindex = 0;
+	int opt;
+
+	libbpf_set_print(libbpf_warning, libbpf_info, NULL);
+
+	/* Parse commands line args */
+	while ((opt = getopt_long(argc, argv, "hDq",
+				  long_options, &longindex)) != -1) {
+		switch (opt) {
+		case 'D':
+			libbpf_set_print(libbpf_warning, libbpf_info,
+					 libbpf_debug);
+			break;
+		case 'q': /* Use in scripting mode */
+			verbose = 0;
+			break;
+		case 'h':
+		default:
+			usage(argv);
+			return EXIT_FAIL_OPTION;
+		}
+	}
+	if (optind >= argc) {
+		usage(argv);
+		printf("ERROR: Expected BPF_FILE argument after options\n");
+		return EXIT_FAIL_OPTION;
+	}
+	snprintf(filename, sizeof(filename), "%s", argv[optind]);
+
+	return test_open_file(filename, verbose);
+}