[PATCH bpf-next v1 3/9] selftests/bpf: tests mkdir, rmdir, unlink and pin in syscall

[Hao Luo <haoluo@google.com>]

Add a subtest in syscall to test bpf_mkdir(), bpf_rmdir(),
bpf_unlink() and object pinning in syscall prog.

Signed-off-by: Hao Luo <haoluo@google.com>
---
 .../selftests/bpf/prog_tests/syscall.c        | 67 +++++++++++++++++-
 .../testing/selftests/bpf/progs/syscall_fs.c  | 69 +++++++++++++++++++
 2 files changed, 135 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/progs/syscall_fs.c

diff --git a/tools/testing/selftests/bpf/prog_tests/syscall.c b/tools/testing/selftests/bpf/prog_tests/syscall.c
index f4d40001155a..782b5fe73096 100644
--- a/tools/testing/selftests/bpf/prog_tests/syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/syscall.c
@@ -1,7 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2021 Facebook */
+#include <sys/stat.h>
 #include <test_progs.h>
 #include "syscall.skel.h"
+#include "syscall_fs.skel.h"
 
 struct args {
 	__u64 log_buf;
@@ -12,7 +14,7 @@ struct args {
 	int btf_fd;
 };
 
-void test_syscall(void)
+static void test_syscall_basic(void)
 {
 	static char verifier_log[8192];
 	struct args ctx = {
@@ -53,3 +55,66 @@ void test_syscall(void)
 	if (ctx.btf_fd > 0)
 		close(ctx.btf_fd);
 }
+
+static void test_syscall_fs(void)
+{
+	char tmpl[] = "/sys/fs/bpf/syscall_XXXXXX";
+	struct stat statbuf = {};
+	static char verifier_log[8192];
+	struct args ctx = {
+		.log_buf = (uintptr_t) verifier_log,
+		.log_size = sizeof(verifier_log),
+		.prog_fd = 0,
+	};
+	LIBBPF_OPTS(bpf_test_run_opts, tattr,
+		.ctx_in = &ctx,
+		.ctx_size_in = sizeof(ctx),
+	);
+	struct syscall_fs *skel = NULL;
+	int err, mkdir_fd, rmdir_fd;
+	char *root, *dir, *path;
+
+	/* prepares test directories */
+	system("mount -t bpf bpffs /sys/fs/bpf");
+	root = mkdtemp(tmpl);
+	chmod(root, 0755);
+
+	/* loads prog */
+	skel = syscall_fs__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_load"))
+		goto cleanup;
+
+	dir = skel->bss->dirname;
+	snprintf(dir, sizeof(skel->bss->dirname), "%s/test", root);
+	path = skel->bss->pathname;
+	snprintf(path, sizeof(skel->bss->pathname), "%s/prog", dir);
+
+	/* tests mkdir */
+	mkdir_fd = bpf_program__fd(skel->progs.mkdir_prog);
+	err = bpf_prog_test_run_opts(mkdir_fd, &tattr);
+	ASSERT_EQ(err, 0, "mkdir_err");
+	ASSERT_EQ(tattr.retval, 0, "mkdir_retval");
+	ASSERT_OK(stat(dir, &statbuf), "mkdir_success");
+	ASSERT_OK(stat(path, &statbuf), "pin_success");
+
+	/* tests rmdir */
+	rmdir_fd = bpf_program__fd(skel->progs.rmdir_prog);
+	err = bpf_prog_test_run_opts(rmdir_fd, &tattr);
+	ASSERT_EQ(err, 0, "rmdir_err");
+	ASSERT_EQ(tattr.retval, 0, "rmdir_retval");
+	ASSERT_ERR(stat(path, &statbuf), "unlink_success");
+	ASSERT_ERR(stat(dir, &statbuf), "rmdir_success");
+
+cleanup:
+	syscall_fs__destroy(skel);
+	if (ctx.prog_fd > 0)
+		close(ctx.prog_fd);
+	rmdir(root);
+}
+
+void test_syscall(void) {
+	if (test__start_subtest("basic"))
+		test_syscall_basic();
+	if (test__start_subtest("filesystem"))
+		test_syscall_fs();
+}
diff --git a/tools/testing/selftests/bpf/progs/syscall_fs.c b/tools/testing/selftests/bpf/progs/syscall_fs.c
new file mode 100644
index 000000000000..9418d1364c09
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/syscall_fs.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Google */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <../../../tools/include/linux/filter.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct args {
+	__u64 log_buf;
+	__u32 log_size;
+	int max_entries;
+	int map_fd;
+	int prog_fd;
+	int btf_fd;
+};
+
+char dirname[64];
+char pathname[64];
+
+SEC("syscall")
+int mkdir_prog(struct args *ctx)
+{
+	static char license[] = "GPL";
+	static struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	static union bpf_attr load_attr = {
+		.prog_type = BPF_PROG_TYPE_XDP,
+		.insn_cnt = sizeof(insns) / sizeof(insns[0]),
+	};
+	static union bpf_attr pin_attr = {
+		.file_flags = 0,
+	};
+	int ret;
+
+	ret = bpf_mkdir(dirname, sizeof(dirname), 0644);
+	if (ret)
+		return ret;
+
+	load_attr.license = (long) license;
+	load_attr.insns = (long) insns;
+	load_attr.log_buf = ctx->log_buf;
+	load_attr.log_size = ctx->log_size;
+	load_attr.log_level = 1;
+	ret = bpf_sys_bpf(BPF_PROG_LOAD, &load_attr, sizeof(load_attr));
+	if (ret < 0)
+		return ret;
+	else if (ret == 0)
+		return -1;
+	ctx->prog_fd = ret;
+
+	pin_attr.pathname = (__u64)pathname;
+	pin_attr.bpf_fd = ret;
+	return bpf_sys_bpf(BPF_OBJ_PIN, &pin_attr, sizeof(pin_attr));
+}
+
+SEC("syscall")
+int rmdir_prog(struct args *ctx)
+{
+	int ret;
+
+	ret = bpf_unlink(pathname, sizeof(pathname));
+	if (ret)
+		return ret;
+
+	return bpf_rmdir(dirname, sizeof(dirname));
+}
-- 
2.35.1.574.g5d30c73bfb-goog