syscalls/mseal02.c: Add new testcase

New testcase is added to check various errnos for mseal(2).

Signed-off-by: Xiao Yang <[email protected]>
Reviewed-by: Cyril Hrubis <[email protected]>

runtest/syscalls

@@ -887,6 +887,7 @@ mremap05 mremap05
 mremap06 mremap06
 
 mseal01 mseal01
+mseal02 mseal02
 
 msgctl01 msgctl01
 msgctl02 msgctl02

testcases/kernel/syscalls/mseal/.gitignore

@@ -1 +1,2 @@
 mseal01
+mseal02

testcases/kernel/syscalls/mseal/mseal02.c

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Xiao Yang <[email protected]>
+ */
+
+/*\
+ * [Description]
+ *
+ * Check various errnos for mseal(2).
+ *
+ * - mseal() fails with EINVAL if flags is invalid.
+ * - mseal() fails with EINVAL if the start address is not page aligned.
+ * - mseal() fails with EINVAL if address range overflows.
+ * - mseal() fails with ENOMEM if the start address is not allocated.
+ * - mseal() fails with ENOMEM if the end address is not allocated.
+ * - mseal() fails with ENOMEM if there is a gap (unallocated memory) between start and end address.
+ *
+ * TODO: support both raw syscall and libc wrapper via .test_variants.
+ */
+
+#define _GNU_SOURCE
+
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+
+static void *start_addr, *unaligned_start_addr, *unallocated_start_addr, *unallocated_end_addr;
+static size_t page_size, twopages_size, fourpages_size, overflow_size;
+
+static struct tcase {
+	void **addr;
+	size_t *len;
+	unsigned long flags;
+	int exp_err;
+} tcases[] = {
+	{&start_addr, &page_size, ULONG_MAX, EINVAL},
+	{&unaligned_start_addr, &page_size, 0, EINVAL},
+	{&start_addr, &overflow_size, 0, EINVAL},
+	{&unallocated_start_addr, &twopages_size, 0, ENOMEM},
+	{&unallocated_end_addr, &twopages_size, 0, ENOMEM},
+	{&start_addr, &fourpages_size, 0, ENOMEM},
+};
+
+static void run(unsigned int n)
+{
+	struct tcase *tc = &tcases[n];
+
+	TST_EXP_FAIL(tst_syscall(__NR_mseal, *tc->addr, *tc->len, tc->flags), tc->exp_err,
+		"mseal(%p, %lu, %lu)", *tc->addr, *tc->len, tc->flags);
+}
+
+static void setup(void)
+{
+	page_size = getpagesize();
+	twopages_size = page_size * 2;
+	fourpages_size = page_size * 4;
+	overflow_size = ULONG_MAX - page_size + 2;
+	start_addr = SAFE_MMAP(NULL, fourpages_size, PROT_READ | PROT_WRITE,
+		MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	unaligned_start_addr = start_addr + 1;
+	SAFE_MUNMAP(start_addr + twopages_size, page_size);
+	unallocated_start_addr = start_addr + twopages_size;
+	unallocated_end_addr = start_addr + page_size;
+}
+
+static void cleanup(void)
+{
+	SAFE_MUNMAP(start_addr, fourpages_size);
+}
+
+static struct tst_test test = {
+	.test = run,
+	.tcnt = ARRAY_SIZE(tcases),
+	.setup = setup,
+	.cleanup = cleanup,
+};