[PATCH bpf-next 5/5] selftests/bpf: Add a series of tests for bpf_snprintf

[Florent Revest]

This exercices most of the format specifiers when things go well.

Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
---
 .../selftests/bpf/prog_tests/snprintf.c       | 71 +++++++++++++++++++
 .../selftests/bpf/progs/test_snprintf.c       | 71 +++++++++++++++++++
 2 files changed, 142 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/snprintf.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_snprintf.c

diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf.c b/tools/testing/selftests/bpf/prog_tests/snprintf.c
new file mode 100644
index 000000000000..23af1dbd1eeb
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/snprintf.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Google LLC. */
+
+#include <test_progs.h>
+#include "test_snprintf.skel.h"
+
+static int duration;
+
+#define EXP_NUM_OUT  "-8 9 96 -424242 1337 DABBAD00"
+#define EXP_NUM_RET  sizeof(EXP_NUM_OUT)
+
+#define EXP_IP_OUT   "127.000.000.001 0000:0000:0000:0000:0000:0000:0000:0001"
+#define EXP_IP_RET   sizeof(EXP_IP_OUT)
+
+/* The third specifier, %pB, depends on compiler inlining so don't check it */
+#define EXP_SYM_OUT  "schedule schedule+0x0/"
+#define MIN_SYM_RET  sizeof(EXP_SYM_OUT)
+
+/* The third specifier, %p, is a hashed pointer which changes on every reboot */
+#define EXP_ADDR_OUT "0000000000000000 ffff00000add4e55 "
+#define EXP_ADDR_RET sizeof(EXP_ADDR_OUT "unknownhashedptr")
+
+#define EXP_STR_OUT  "str1 longstr"
+#define EXP_STR_RET  sizeof(EXP_STR_OUT)
+
+#define EXP_OVER_OUT {'%', 'o', 'v', 'e', 'r'}
+#define EXP_OVER_RET 10
+
+void test_snprintf(void)
+{
+	char exp_addr_out[] = EXP_ADDR_OUT;
+	char exp_over_out[] = EXP_OVER_OUT;
+	char exp_sym_out[]  = EXP_SYM_OUT;
+	struct test_snprintf *skel;
+	int err;
+
+	skel = test_snprintf__open_and_load();
+	if (CHECK(!skel, "skel_open", "failed to open and load skeleton\n"))
+		return;
+
+	err = test_snprintf__attach(skel);
+	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+		goto cleanup;
+
+	/* trigger tracepoint */
+	usleep(1);
+
+	ASSERT_STREQ(skel->bss->num_out, EXP_NUM_OUT, "num_out");
+	ASSERT_EQ(skel->bss->num_ret, EXP_NUM_RET, "num_ret");
+
+	ASSERT_STREQ(skel->bss->ip_out, EXP_IP_OUT, "ip_out");
+	ASSERT_EQ(skel->bss->ip_ret, EXP_IP_RET, "ip_ret");
+
+	ASSERT_OK(memcmp(skel->bss->sym_out, exp_sym_out,
+			 sizeof(exp_sym_out) - 1), "sym_out");
+	ASSERT_LT(MIN_SYM_RET, skel->bss->sym_ret, "sym_ret");
+
+	ASSERT_OK(memcmp(skel->bss->addr_out, exp_addr_out,
+			 sizeof(exp_addr_out) - 1), "addr_out");
+	ASSERT_EQ(skel->bss->addr_ret, EXP_ADDR_RET, "addr_ret");
+
+	ASSERT_STREQ(skel->bss->str_out, EXP_STR_OUT, "str_out");
+	ASSERT_EQ(skel->bss->str_ret, EXP_STR_RET, "str_ret");
+
+	ASSERT_OK(memcmp(skel->bss->over_out, exp_over_out,
+			 sizeof(exp_over_out)), "over_out");
+	ASSERT_EQ(skel->bss->over_ret, EXP_OVER_RET, "over_ret");
+
+cleanup:
+	test_snprintf__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_snprintf.c b/tools/testing/selftests/bpf/progs/test_snprintf.c
new file mode 100644
index 000000000000..6c8aa4988e69
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_snprintf.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Google LLC. */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#define OUT_LEN 64
+
+/* Integer types */
+static const char num_fmt[] = "%d %u %x %li %llu %lX";
+#define NUMBERS -8, 9, 150, -424242, 1337, 0xDABBAD00
+
+char num_out[OUT_LEN] = {};
+long num_ret = 0;
+
+/* IP addresses */
+static const char ip_fmt[] = "%pi4 %pI6";
+static const __u8 dummy_ipv4[] = {127, 0, 0, 1}; /* 127.0.0.1 */
+static const __u32 dummy_ipv6[] = {0, 0, 0, bpf_htonl(1)}; /* ::1/128 */
+#define IPS &dummy_ipv4, &dummy_ipv6
+
+char ip_out[OUT_LEN] = {};
+long ip_ret = 0;
+
+/* Symbol lookup formatting */
+static const char sym_fmt[] = "%ps %pS %pB";
+extern const void schedule __ksym;
+#define SYMBOLS &schedule, &schedule, &schedule
+
+char sym_out[OUT_LEN] = {};
+long sym_ret = 0;
+
+/* Kernel pointers */
+static const char addr_fmt[] = "%pK %px %p";
+#define ADDRESSES 0, 0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55
+
+char addr_out[OUT_LEN] = {};
+long addr_ret = 0;
+
+/* Strings embedding */
+static const char str_fmt[] = "%s %+05s";
+static const char str1[] = "str1";
+static const char longstr[] = "longstr";
+#define STRINGS str1, longstr
+
+char str_out[OUT_LEN] = {};
+long str_ret = 0;
+
+/* Overflow */
+static const char over_fmt[] = "%%overflow";
+
+#define OVER_OUT_LEN 6
+char over_out[OVER_OUT_LEN] = {};
+long over_ret = 0;
+
+SEC("raw_tp/sys_enter")
+int handler(const void *ctx)
+{
+	num_ret  = BPF_SNPRINTF(num_out,  OUT_LEN, num_fmt,  NUMBERS);
+	ip_ret   = BPF_SNPRINTF(ip_out,   OUT_LEN, ip_fmt,   IPS);
+	sym_ret  = BPF_SNPRINTF(sym_out,  OUT_LEN, sym_fmt,  SYMBOLS);
+	addr_ret = BPF_SNPRINTF(addr_out, OUT_LEN, addr_fmt, ADDRESSES);
+	str_ret  = BPF_SNPRINTF(str_out,  OUT_LEN, str_fmt,  STRINGS);
+	over_ret = BPF_SNPRINTF(over_out, OVER_OUT_LEN, over_fmt);
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.30.1.766.gb4fecdf3b7-goog