[LTP] [LTP PATCH v4 3/5] ftrace: Convert ftrace_regression02.sh to C

[Praveen K Pandey]

Convert ftrace_regression02.sh to C implementation using LTP new API.

This test verifies that the signal:signal_generate tracepoint exposes 'grp='
and 'res=' fields. These fields were added by commits 6c303d3 and 163566f
in kernel 3.2. The test enables the signal_generate event, generates signals,
and checks the trace output for the presence of both fields.

The test requires root to access and configure the ftrace subsystem via debugfs.
Uses .min_kver to enforce kernel version requirement instead of inline check.

Signed-off-by: Praveen K Pandey <praveen@linux.ibm.com>
---
 .../tracing/ftrace_test/ftrace_regression02.c | 103 ++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 testcases/kernel/tracing/ftrace_test/ftrace_regression02.c

diff --git a/testcases/kernel/tracing/ftrace_test/ftrace_regression02.c b/testcases/kernel/tracing/ftrace_test/ftrace_regression02.c
new file mode 100644
index 000000000..4d960cb82
--- /dev/null
+++ b/testcases/kernel/tracing/ftrace_test/ftrace_regression02.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2015 Red Hat Inc.
+ * Copyright (c) 2024 Linux Test Project
+ * Copyright (c) IBM, 2026
+ *
+ * Author: Li Wang <liwang@redhat.com>
+ * Converted to C by: Praveen K Pandey <praveen@linux.ibm.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify that signal:signal_generate tracepoint exposes 'grp=' and 'res=' fields.
+ *
+ * This test verifies kernel commits that added more information to the
+ * signal_generate tracepoint:
+ *
+ * - Commit 6c303d3 (tracing: let trace_signal_generate() report more info...)
+ * - Commit 163566f (tracing: send_sigqueue() needs trace_signal_generate())
+ *
+ * These fields were added in kernel 3.2.
+ *
+ * Requires root to access and configure the ftrace subsystem via debugfs.
+ *
+ * [Algorithm]
+ *
+ * - Enable signal:signal_generate event
+ * - Enable tracing
+ * - Generate signals by running commands
+ * - Read trace output and search for 'grp=' and 'res=' fields
+ * - Test passes if both fields are found in the trace
+ */
+
+#include "tst_test.h"
+#include "ftrace_lib.h"
+
+#define SIGNAL_LOOP 100
+
+static void run_test(void)
+{
+	int i;
+	char *trace_content;
+	int found = 0;
+
+	/* Set event */
+	if (ftrace_write_file("set_event", "signal:signal_generate\n") != 0)
+		tst_brk(TBROK, "Failed to set signal:signal_generate event");
+
+	/* Enable tracing */
+	ftrace_enable_tracing();
+
+	/* Clear trace buffer */
+	ftrace_clear_trace();
+
+	/* Generate some signals by running commands */
+	for (i = 0; i < SIGNAL_LOOP; i++) {
+		/* Run a simple command that will generate signals */
+		if (system("ls -l /proc > /dev/null 2>&1") == -1)
+			tst_res(TINFO, "Command execution failed, continuing...");
+	}
+
+	/* Wait for trace to be written and contain signal events */
+	trace_content = TST_RETRY_FUNC(ftrace_read_file("trace"), TST_RETVAL_NOTNULL);
+	if (!trace_content)
+		tst_brk(TBROK, "Failed to read trace file");
+
+	/* Check for 'grp=' and 'res=' fields in trace */
+	if (strstr(trace_content, "grp=") && strstr(trace_content, "res="))
+		found = 1;
+
+	free(trace_content);
+
+	if (found)
+		tst_res(TPASS, "signal_generate event contains grp and res fields");
+	else
+		tst_res(TFAIL, "signal_generate event missing grp or res fields");
+}
+
+static void setup(void)
+{
+	ftrace_initialize();
+}
+
+static void cleanup(void)
+{
+	ftrace_cleanup();
+}
+
+static struct tst_test test = {
+	.test_all = run_test,
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.needs_tmpdir = 1,
+	.min_kver = "3.2",
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "6c303d3"},
+		{"linux-git", "163566f"},
+		{}
+	}
+};
+
-- 
2.50.1