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Message-Id: <1605291013-22575-4-git-send-email-alan.maguire@oracle.com>
Date: Fri, 13 Nov 2020 18:10:13 +0000
From: Alan Maguire <alan.maguire@...cle.com>
To: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org
Cc: kafai@...com, songliubraving@...com, yhs@...com,
john.fastabend@...il.com, kpsingh@...omium.org,
rostedt@...dmis.org, mingo@...hat.com, haoluo@...gle.com,
jolsa@...nel.org, quentin@...valent.com,
linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
bpf@...r.kernel.org
Subject: [RFC bpf-next 3/3] selftests/bpf: verify module-specific types can be shown via bpf_snprintf_btf
Verify that specifying a module name in "struct btf_ptr *" along
with a type id of a module-specific type will succeed.
veth_stats_rx() is chosen because its function signature consists
of a module-specific type "struct veth_stats" and a kernel-specific
one "struct net_device".
Signed-off-by: Alan Maguire <alan.maguire@...cle.com>
---
.../selftests/bpf/prog_tests/snprintf_btf_mod.c | 96 ++++++++++++++++++++++
tools/testing/selftests/bpf/progs/btf_ptr.h | 1 +
tools/testing/selftests/bpf/progs/veth_stats_rx.c | 73 ++++++++++++++++
3 files changed, 170 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/snprintf_btf_mod.c
create mode 100644 tools/testing/selftests/bpf/progs/veth_stats_rx.c
diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf_btf_mod.c b/tools/testing/selftests/bpf/prog_tests/snprintf_btf_mod.c
new file mode 100644
index 0000000..f1b12df
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/snprintf_btf_mod.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <linux/btf.h>
+#include <bpf/btf.h>
+#include "veth_stats_rx.skel.h"
+
+#define VETH_NAME "bpfveth0"
+
+/* Demonstrate that bpf_snprintf_btf succeeds for both module-specific
+ * and kernel-defined data structures; veth_stats_rx() is used as
+ * it has both module-specific and kernel-defined data as arguments.
+ * This test assumes that veth is built as a module and will skip if not.
+ */
+void test_snprintf_btf_mod(void)
+{
+ struct btf *vmlinux_btf = NULL, *veth_btf = NULL;
+ struct veth_stats_rx *skel = NULL;
+ struct veth_stats_rx__bss *bss;
+ int err, duration = 0;
+ __u32 id;
+
+ err = system("ip link add name " VETH_NAME " type veth");
+ if (CHECK(err, "system", "ip link add veth failed: %d\n", err))
+ return;
+
+ vmlinux_btf = btf__parse_raw("/sys/kernel/btf/vmlinux");
+ err = libbpf_get_error(vmlinux_btf);
+ if (CHECK(err, "parse vmlinux BTF", "failed parsing vmlinux BTF: %d\n",
+ err))
+ goto cleanup;
+ veth_btf = btf__parse_raw_split("/sys/kernel/btf/veth", vmlinux_btf);
+ err = libbpf_get_error(veth_btf);
+ if (err == -ENOENT) {
+ printf("%s:SKIP:no BTF info for veth\n", __func__);
+ test__skip();
+ goto cleanup;
+ }
+
+ if (CHECK(err, "parse veth BTF", "failed parsing veth BTF: %d\n", err))
+ goto cleanup;
+
+ skel = veth_stats_rx__open();
+ if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+ goto cleanup;
+
+ err = veth_stats_rx__load(skel);
+ if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
+ goto cleanup;
+
+ bss = skel->bss;
+
+ bss->veth_stats_btf_id = btf__find_by_name(veth_btf, "veth_stats");
+
+ if (CHECK(bss->veth_stats_btf_id <= 0, "find 'struct veth_stats'",
+ "could not find 'struct veth_stats' in veth BTF: %d",
+ bss->veth_stats_btf_id))
+ goto cleanup;
+
+ err = veth_stats_rx__attach(skel);
+ if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+ goto cleanup;
+
+ /* generate stats event, then delete; this ensures the program
+ * triggers prior to reading status.
+ */
+ err = system("ethtool -S " VETH_NAME " > /dev/null");
+ if (CHECK(err, "system", "ethtool -S failed: %d\n", err))
+ goto cleanup;
+
+ system("ip link delete " VETH_NAME);
+
+ /*
+ * Make sure veth_stats_rx program was triggered and it set
+ * expected return values from bpf_trace_printk()s and all
+ * tests ran.
+ */
+ if (CHECK(bss->ret <= 0,
+ "bpf_snprintf_btf: got return value",
+ "ret <= 0 %ld test %d\n", bss->ret, bss->ran_subtests))
+ goto cleanup;
+
+ if (CHECK(bss->ran_subtests == 0, "check if subtests ran",
+ "no subtests ran, did BPF program run?"))
+ goto cleanup;
+
+ if (CHECK(bss->num_subtests != bss->ran_subtests,
+ "check all subtests ran",
+ "only ran %d of %d tests\n", bss->num_subtests,
+ bss->ran_subtests))
+ goto cleanup;
+
+cleanup:
+ system("ip link delete " VETH_NAME ">/dev/null 2>&1");
+ if (skel)
+ veth_stats_rx__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/btf_ptr.h b/tools/testing/selftests/bpf/progs/btf_ptr.h
index c3c9797..afef9b3 100644
--- a/tools/testing/selftests/bpf/progs/btf_ptr.h
+++ b/tools/testing/selftests/bpf/progs/btf_ptr.h
@@ -17,6 +17,7 @@ struct btf_ptr {
void *ptr;
__u32 type_id;
__u32 flags;
+ const char *module;
};
enum {
diff --git a/tools/testing/selftests/bpf/progs/veth_stats_rx.c b/tools/testing/selftests/bpf/progs/veth_stats_rx.c
new file mode 100644
index 0000000..6ec7ce2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/veth_stats_rx.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Oracle and/or its affiliates. */
+
+#include "btf_ptr.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+#include <errno.h>
+
+long ret = 0;
+int num_subtests = 0;
+int ran_subtests = 0;
+s32 veth_stats_btf_id = 0;
+
+#define STRSIZE 2048
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, char[STRSIZE]);
+} strdata SEC(".maps");
+
+SEC("kprobe/veth_stats_rx")
+int veth_stats_rx(struct pt_regs *ctx)
+{
+ static __u64 flags[] = { 0, BTF_F_COMPACT, BTF_F_ZERO, BTF_F_PTR_RAW,
+ BTF_F_NONAME, BTF_F_COMPACT | BTF_F_ZERO |
+ BTF_F_PTR_RAW | BTF_F_NONAME };
+ static const char mod[] = "veth";
+ const char *mods[] = { mod, 0 };
+ static struct btf_ptr p = { };
+ __u32 btf_ids[] = { 0, 0 };
+ void *ptrs[] = { 0, 0 };
+ __u32 key = 0;
+ int i, j;
+ char *str;
+
+ btf_ids[0] = veth_stats_btf_id;
+ ptrs[0] = (void *)PT_REGS_PARM1_CORE(ctx);
+#if __has_builtin(__builtin_btf_type_id)
+ btf_ids[1] = bpf_core_type_id_kernel(struct net_device);
+ ptrs[1] = (void *)PT_REGS_PARM2_CORE(ctx);
+#endif
+ str = bpf_map_lookup_elem(&strdata, &key);
+ if (!str)
+ return 0;
+
+ for (i = 0; i < ARRAY_SIZE(btf_ids); i++) {
+ if (btf_ids[i] == 0)
+ continue;
+ p.type_id = btf_ids[i];
+ p.ptr = ptrs[i];
+ p.module = mods[i];
+ for (j = 0; j < ARRAY_SIZE(flags); j++) {
+ ++num_subtests;
+ ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0);
+ if (ret < 0)
+ bpf_printk("returned %d when writing id %d",
+ ret, p.type_id);
+ ++ran_subtests;
+ }
+ }
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
1.8.3.1
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