1 files changed, 72 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/trace_printk.c b/tools/testing/selftests/bpf/prog_tests/trace_printk.c
new file mode 100644
index 000000000000..cade7f12315f
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/trace_printk.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Oracle and/or its affiliates. */
+
+#include <test_progs.h>
+
+#include "trace_printk.lskel.h"
+
+#define TRACEBUF	"/sys/kernel/debug/tracing/trace_pipe"
+#define SEARCHMSG	"testing,testing"
+
+void serial_test_trace_printk(void)
+{
+	struct trace_printk_lskel__bss *bss;
+	int err = 0, iter = 0, found = 0;
+	struct trace_printk_lskel *skel;
+	char *buf = NULL;
+	FILE *fp = NULL;
+	size_t buflen;
+
+	skel = trace_printk_lskel__open();
+	if (!ASSERT_OK_PTR(skel, "trace_printk__open"))
+		return;
+
+	ASSERT_EQ(skel->rodata->fmt[0], 'T', "skel->rodata->fmt[0]");
+	skel->rodata->fmt[0] = 't';
+
+	err = trace_printk_lskel__load(skel);
+	if (!ASSERT_OK(err, "trace_printk__load"))
+		goto cleanup;
+
+	bss = skel->bss;
+
+	err = trace_printk_lskel__attach(skel);
+	if (!ASSERT_OK(err, "trace_printk__attach"))
+		goto cleanup;
+
+	fp = fopen(TRACEBUF, "r");
+	if (!ASSERT_OK_PTR(fp, "fopen(TRACEBUF)"))
+		goto cleanup;
+
+	/* We do not want to wait forever if this test fails... */
+	fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
+
+	/* wait for tracepoint to trigger */
+	usleep(1);
+	trace_printk_lskel__detach(skel);
+
+	if (!ASSERT_GT(bss->trace_printk_ran, 0, "bss->trace_printk_ran"))
+		goto cleanup;
+
+	if (!ASSERT_GT(bss->trace_printk_ret, 0, "bss->trace_printk_ret"))
+		goto cleanup;
+
+	/* verify our search string is in the trace buffer */
+	while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
+		if (strstr(buf, SEARCHMSG) != NULL)
+			found++;
+		if (found == bss->trace_printk_ran)
+			break;
+		if (++iter > 1000)
+			break;
+	}
+
+	if (!ASSERT_EQ(found, bss->trace_printk_ran, "found"))
+		goto cleanup;
+
+cleanup:
+	trace_printk_lskel__destroy(skel);
+	free(buf);
+	if (fp)
+		fclose(fp);
+}