[LTP] [PATCH 1/2] syscalls: Add test for splicing from /dev/zero and /dev/full

[Cyril Hrubis]

Both of these devices produce zeroes when read.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
---
 runtest/syscalls                            |  1 +
 testcases/kernel/syscalls/splice/.gitignore |  1 +
 testcases/kernel/syscalls/splice/splice08.c | 88 +++++++++++++++++++++
 3 files changed, 90 insertions(+)
 create mode 100644 testcases/kernel/syscalls/splice/splice08.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 4ed2b5602..0889f58a1 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1517,6 +1517,7 @@ splice04 splice04
 splice05 splice05
 splice06 splice06
 splice07 splice07
+splice08 splice08
 
 tee01 tee01
 tee02 tee02
diff --git a/testcases/kernel/syscalls/splice/.gitignore b/testcases/kernel/syscalls/splice/.gitignore
index 88a8dff78..9453cf93a 100644
--- a/testcases/kernel/syscalls/splice/.gitignore
+++ b/testcases/kernel/syscalls/splice/.gitignore
@@ -5,3 +5,4 @@
 /splice05
 /splice06
 /splice07
+/splice08
diff --git a/testcases/kernel/syscalls/splice/splice08.c b/testcases/kernel/syscalls/splice/splice08.c
new file mode 100644
index 000000000..cdd51b66c
--- /dev/null
+++ b/testcases/kernel/syscalls/splice/splice08.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+/*\
+ * [Description]
+ *
+ * Test for splicing from /dev/zero and /dev/full.
+ *
+ * The support for splicing from /dev/zero and /dev/full was removed in:
+ * c6585011bc1d ("splice: Remove generic_file_splice_read()")
+ *
+ * And added back in:
+ * 1b057bd800c3 ("drivers/char/mem: implement splice() for /dev/zero, /dev/full")
+ */
+
+#define _GNU_SOURCE
+#include "tst_test.h"
+
+static int fd_zero;
+static int fd_full;
+
+static void test_splice(unsigned int bytes, int dev_fd)
+{
+	int pipefd[2];
+	char buf[bytes];
+	size_t i;
+	int fail = 0;
+
+	memset(buf, 0xff, sizeof(buf));
+
+	SAFE_PIPE(pipefd);
+
+	TST_EXP_POSITIVE(splice(dev_fd, NULL, pipefd[1], NULL, sizeof(buf), 0));
+
+	if (!TST_PASS)
+		goto ret;
+
+	SAFE_READ(1, pipefd[0], buf, sizeof(buf));
+
+	for (i = 0; i < sizeof(buf); i++) {
+		if (buf[i])
+			fail++;
+	}
+
+	if (fail)
+		tst_res(TFAIL, "Non-zero bytes spliced from /dev/zero");
+	else
+		tst_res(TPASS, "All bytes spliced from /dev/zero are zeroed");
+
+ret:
+	SAFE_CLOSE(pipefd[0]);
+	SAFE_CLOSE(pipefd[1]);
+}
+
+static void verify_splice(unsigned int n)
+{
+	unsigned int bytes = 1009 * n;
+
+	tst_res(TINFO, "Splicing %u bytes from /dev/zero", bytes);
+	test_splice(bytes, fd_zero);
+	tst_res(TINFO, "Splicing %u bytes from /dev/full", bytes);
+	test_splice(bytes, fd_full);
+}
+
+static void setup(void)
+{
+	fd_zero = SAFE_OPEN("/dev/zero", O_RDONLY);
+	fd_full = SAFE_OPEN("/dev/full", O_RDONLY);
+}
+
+static void cleanup(void)
+{
+	if (fd_zero > 0)
+		SAFE_CLOSE(fd_zero);
+
+	if (fd_full > 0)
+		SAFE_CLOSE(fd_full);
+}
+
+static struct tst_test test = {
+	.test = verify_splice,
+	.tcnt = 9,
+	.setup = setup,
+	.cleanup = cleanup,
+	.min_kver = "6.7",
+};
-- 
2.43.2