bpf: Refactor and bug fix in test_func_type in test_btf.c

1) bpf_load_program_xattr() is absorbing the EBIG error
   which makes testing this case impossible.  It is replaced
   with a direct syscall(__NR_bpf, BPF_PROG_LOAD,...).
2) The test_func_type() is renamed to test_info_raw() to
   prepare for the new line_info test in the next patch.
3) The bpf_obj_get_info_by_fd() testing for func_info
   is refactored to test_get_finfo().  A new
   test_get_linfo() will be added in the next patch
   for testing line_info purpose.
4) The test->func_info_cnt is checked instead of
   a static value "2".
5) Remove unnecessary "\n" in error message.
6) Adding back info_raw_test_num to the cmd arg such
   that a specific test case can be tested, like
   all other existing tests.

7) Fix a bug in handling expected_prog_load_failure.
   A test could pass even if prog_fd != -1 while
   expected_prog_load_failure is true.
8) The min rec_size check should be < 8 instead of < 4.

Fixes: 4798c4b ("tools/bpf: extends test_btf to test load/retrieve func_type info")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/test_btf.c

@@ -6,6 +6,7 @@
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/filter.h>
+#include <linux/unistd.h>
 #include <bpf/bpf.h>
 #include <sys/resource.h>
 #include <libelf.h>
@@ -114,12 +115,13 @@ static struct args {
 	unsigned int raw_test_num;
 	unsigned int file_test_num;
 	unsigned int get_info_test_num;
+	unsigned int info_raw_test_num;
 	bool raw_test;
 	bool file_test;
 	bool get_info_test;
 	bool pprint_test;
 	bool always_log;
-	bool func_type_test;
+	bool info_raw_test;
 } args;
 
 static char btf_log_buf[BTF_LOG_BUF_SIZE];
@@ -3051,7 +3053,7 @@ static int test_pprint(void)
 	return err;
 }
 
-static struct btf_func_type_test {
+static struct prog_info_raw_test {
 	const char *descr;
 	const char *str_sec;
 	__u32 raw_types[MAX_NR_RAW_TYPES];
@@ -3062,7 +3064,7 @@ static struct btf_func_type_test {
 	__u32 func_info_rec_size;
 	__u32 func_info_cnt;
 	bool expected_prog_load_failure;
-} func_type_test[] = {
+} info_raw_tests[] = {
 {
 	.descr = "func_type (main func + one sub)",
 	.raw_types = {
@@ -3198,90 +3200,44 @@ static size_t probe_prog_length(const struct bpf_insn *fp)
 	return len + 1;
 }
 
-static int do_test_func_type(int test_num)
+static int test_get_finfo(const struct prog_info_raw_test *test,
+			  int prog_fd)
 {
-	const struct btf_func_type_test *test = &func_type_test[test_num];
-	unsigned int raw_btf_size, info_len, rec_size;
-	int i, btf_fd = -1, prog_fd = -1, err = 0;
-	struct bpf_load_program_attr attr = {};
-	void *raw_btf, *func_info = NULL;
 	struct bpf_prog_info info = {};
 	struct bpf_func_info *finfo;
-
-	fprintf(stderr, "%s......", test->descr);
-	raw_btf = btf_raw_create(&hdr_tmpl, test->raw_types,
-				 test->str_sec, test->str_sec_size,
-				 &raw_btf_size);
-
-	if (!raw_btf)
-		return -1;
-
-	*btf_log_buf = '\0';
-	btf_fd = bpf_load_btf(raw_btf, raw_btf_size,
-			      btf_log_buf, BTF_LOG_BUF_SIZE,
-			      args.always_log);
-	free(raw_btf);
-
-	if (CHECK(btf_fd == -1, "invalid btf_fd errno:%d", errno)) {
-		err = -1;
-		goto done;
-	}
-
-	if (*btf_log_buf && args.always_log)
-		fprintf(stderr, "\n%s", btf_log_buf);
-
-	attr.prog_type = test->prog_type;
-	attr.insns = test->insns;
-	attr.insns_cnt = probe_prog_length(attr.insns);
-	attr.license = "GPL";
-	attr.prog_btf_fd = btf_fd;
-	attr.func_info_rec_size = test->func_info_rec_size;
-	attr.func_info_cnt = test->func_info_cnt;
-	attr.func_info = test->func_info;
-
-	*btf_log_buf = '\0';
-	prog_fd = bpf_load_program_xattr(&attr, btf_log_buf,
-					 BTF_LOG_BUF_SIZE);
-	if (test->expected_prog_load_failure && prog_fd == -1) {
-		err = 0;
-		goto done;
-	}
-	if (CHECK(prog_fd == -1, "invalid prog_id errno:%d", errno)) {
-		fprintf(stderr, "%s\n", btf_log_buf);
-		err = -1;
-		goto done;
-	}
+	__u32 info_len, rec_size, i;
+	void *func_info = NULL;
+	int err;
 
 	/* get necessary lens */
 	info_len = sizeof(struct bpf_prog_info);
 	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
 	if (CHECK(err == -1, "invalid get info (1st) errno:%d", errno)) {
 		fprintf(stderr, "%s\n", btf_log_buf);
-		err = -1;
-		goto done;
+		return -1;
 	}
-	if (CHECK(info.func_info_cnt != 2,
-		  "incorrect info.func_info_cnt (1st) %d\n",
+	if (CHECK(info.func_info_cnt != test->func_info_cnt,
+		  "incorrect info.func_info_cnt (1st) %d",
 		  info.func_info_cnt)) {
-		err = -1;
-		goto done;
+		return -1;
 	}
+
 	rec_size = info.func_info_rec_size;
-	if (CHECK(rec_size < 4,
-		  "incorrect info.func_info_rec_size (1st) %d\n", rec_size)) {
-		err = -1;
-		goto done;
+	if (CHECK(rec_size < 8,
+		  "incorrect info.func_info_rec_size (1st) %d", rec_size)) {
+		return -1;
 	}
 
+	if (!info.func_info_cnt)
+		return 0;
+
 	func_info = malloc(info.func_info_cnt * rec_size);
-	if (CHECK(!func_info, "out of memory")) {
-		err = -1;
-		goto done;
-	}
+	if (CHECK(!func_info, "out of memory"))
+		return -1;
 
 	/* reset info to only retrieve func_info related data */
 	memset(&info, 0, sizeof(info));
-	info.func_info_cnt = 2;
+	info.func_info_cnt = test->func_info_cnt;
 	info.func_info_rec_size = rec_size;
 	info.func_info = ptr_to_u64(func_info);
 	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
@@ -3290,14 +3246,14 @@ static int do_test_func_type(int test_num)
 		err = -1;
 		goto done;
 	}
-	if (CHECK(info.func_info_cnt != 2,
-		  "incorrect info.func_info_cnt (2nd) %d\n",
+	if (CHECK(info.func_info_cnt != test->func_info_cnt,
+		  "incorrect info.func_info_cnt (2nd) %d",
 		  info.func_info_cnt)) {
 		err = -1;
 		goto done;
 	}
-	if (CHECK(info.func_info_rec_size != rec_size,
-		  "incorrect info.func_info_rec_size (2nd) %d\n",
+	if (CHECK(info.func_info_rec_size < 8,
+		  "incorrect info.func_info_rec_size (2nd) %d",
 		  info.func_info_rec_size)) {
 		err = -1;
 		goto done;
@@ -3310,7 +3266,7 @@ static int do_test_func_type(int test_num)
 	}
 
 	finfo = func_info;
-	for (i = 0; i < 2; i++) {
+	for (i = 0; i < test->func_info_cnt; i++) {
 		if (CHECK(finfo->type_id != test->func_info[i][1],
 			  "incorrect func_type %u expected %u",
 			  finfo->type_id, test->func_info[i][1])) {
@@ -3320,41 +3276,114 @@ static int do_test_func_type(int test_num)
 		finfo = (void *)finfo + rec_size;
 	}
 
+	err = 0;
+
+done:
+	free(func_info);
+	return err;
+}
+
+static int do_test_info_raw(unsigned int test_num)
+{
+	const struct prog_info_raw_test *test = &info_raw_tests[test_num - 1];
+	int btf_fd = -1, prog_fd = -1, err = 0;
+	unsigned int raw_btf_size;
+	union bpf_attr attr = {};
+	void *raw_btf;
+
+	fprintf(stderr, "BTF prog info raw test[%u] (%s): ", test_num, test->descr);
+	raw_btf = btf_raw_create(&hdr_tmpl, test->raw_types,
+				 test->str_sec, test->str_sec_size,
+				 &raw_btf_size);
+
+	if (!raw_btf)
+		return -1;
+
+	*btf_log_buf = '\0';
+	btf_fd = bpf_load_btf(raw_btf, raw_btf_size,
+			      btf_log_buf, BTF_LOG_BUF_SIZE,
+			      args.always_log);
+	free(raw_btf);
+
+	if (CHECK(btf_fd == -1, "invalid btf_fd errno:%d", errno)) {
+		err = -1;
+		goto done;
+	}
+
+	if (*btf_log_buf && args.always_log)
+		fprintf(stderr, "\n%s", btf_log_buf);
+	*btf_log_buf = '\0';
+
+	attr.prog_type = test->prog_type;
+	attr.insns = ptr_to_u64(test->insns);
+	attr.insn_cnt = probe_prog_length(test->insns);
+	attr.license = ptr_to_u64("GPL");
+	attr.prog_btf_fd = btf_fd;
+	attr.func_info_rec_size = test->func_info_rec_size;
+	attr.func_info_cnt = test->func_info_cnt;
+	attr.func_info = ptr_to_u64(test->func_info);
+	attr.log_buf = ptr_to_u64(btf_log_buf);
+	attr.log_size = BTF_LOG_BUF_SIZE;
+	attr.log_level = 1;
+
+	prog_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
+	err = ((prog_fd == -1) != test->expected_prog_load_failure);
+	if (CHECK(err, "prog_fd:%d expected_prog_load_failure:%u errno:%d",
+		  prog_fd, test->expected_prog_load_failure, errno)) {
+		err = -1;
+		goto done;
+	}
+
+	if (prog_fd == -1)
+		goto done;
+
+	err = test_get_finfo(test, prog_fd);
+	if (err)
+		goto done;
+
 done:
+	if (!err)
+		fprintf(stderr, "OK");
+
 	if (*btf_log_buf && (err || args.always_log))
 		fprintf(stderr, "\n%s", btf_log_buf);
 
 	if (btf_fd != -1)
 		close(btf_fd);
 	if (prog_fd != -1)
 		close(prog_fd);
-	free(func_info);
+
 	return err;
 }
 
-static int test_func_type(void)
+static int test_info_raw(void)
 {
 	unsigned int i;
 	int err = 0;
 
-	for (i = 0; i < ARRAY_SIZE(func_type_test); i++)
-		err |= count_result(do_test_func_type(i));
+	if (args.info_raw_test_num)
+		return count_result(do_test_info_raw(args.info_raw_test_num));
+
+	for (i = 1; i <= ARRAY_SIZE(info_raw_tests); i++)
+		err |= count_result(do_test_info_raw(i));
 
 	return err;
 }
 
 static void usage(const char *cmd)
 {
-	fprintf(stderr, "Usage: %s [-l] [[-r test_num (1 - %zu)] |"
-			" [-g test_num (1 - %zu)] |"
-			" [-f test_num (1 - %zu)] | [-p] | [-k] ]\n",
+	fprintf(stderr, "Usage: %s [-l] [[-r btf_raw_test_num (1 - %zu)] |\n"
+			"\t[-g btf_get_info_test_num (1 - %zu)] |\n"
+			"\t[-f btf_file_test_num (1 - %zu)] |\n"
+			"\t[-k btf_prog_info_raw_test_num (1 - %zu)] |\n"
+			"\t[-p (pretty print test)]]\n",
 		cmd, ARRAY_SIZE(raw_tests), ARRAY_SIZE(get_info_tests),
-		ARRAY_SIZE(file_tests));
+		ARRAY_SIZE(file_tests), ARRAY_SIZE(info_raw_tests));
 }
 
 static int parse_args(int argc, char **argv)
 {
-	const char *optstr = "lpkf:r:g:";
+	const char *optstr = "lpk:f:r:g:";
 	int opt;
 
 	while ((opt = getopt(argc, argv, optstr)) != -1) {
@@ -3378,7 +3407,8 @@ static int parse_args(int argc, char **argv)
 			args.pprint_test = true;
 			break;
 		case 'k':
-			args.func_type_test = true;
+			args.info_raw_test_num = atoi(optarg);
+			args.info_raw_test = true;
 			break;
 		case 'h':
 			usage(argv[0]);
@@ -3413,6 +3443,14 @@ static int parse_args(int argc, char **argv)
 		return -1;
 	}
 
+	if (args.info_raw_test_num &&
+	    (args.info_raw_test_num < 1 ||
+	     args.info_raw_test_num > ARRAY_SIZE(info_raw_tests))) {
+		fprintf(stderr, "BTF prog info raw test number must be [1 - %zu]\n",
+			ARRAY_SIZE(info_raw_tests));
+		return -1;
+	}
+
 	return 0;
 }
 
@@ -3445,16 +3483,17 @@ int main(int argc, char **argv)
 	if (args.pprint_test)
 		err |= test_pprint();
 
-	if (args.func_type_test)
-		err |= test_func_type();
+	if (args.info_raw_test)
+		err |= test_info_raw();
 
 	if (args.raw_test || args.get_info_test || args.file_test ||
-	    args.pprint_test || args.func_type_test)
+	    args.pprint_test || args.info_raw_test)
 		goto done;
 
 	err |= test_raw();
 	err |= test_get_info();
 	err |= test_file();
+	err |= test_info_raw();
 
 done:
 	print_summary();