tests: check decoding of ioctl TIOCM* commands

* tests/ioctl_tiocm.c: New file.
* tests/gen_tests.in (ioctl_tiocm): New test.
* tests/pure_executables.list: Add ioctl_tiocm.
* tests/.gitignore: Likewise.

4 files changed, 99 insertions, 0 deletions

diff --git a/tests/.gitignore b/tests/.gitignore
index 581ab324d..5459d8f4b 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -378,6 +378,7 @@ ioctl_sg_io_v4
 ioctl_sock
 ioctl_sock_gifconf
 ioctl_tee
+ioctl_tiocm
 ioctl_ubi
 ioctl_ubi-success
 ioctl_uffdio
diff --git a/tests/gen_tests.in b/tests/gen_tests.in
index b822add55..d1cbf0e94 100644
--- a/tests/gen_tests.in
+++ b/tests/gen_tests.in
@@ -396,6 +396,7 @@ ioctl_sg_io_v4	+ioctl.test
 ioctl_sock	+ioctl.test -a23
 ioctl_sock_gifconf	+ioctl.test -a28 -s1
 ioctl_tee	+ioctl.test
+ioctl_tiocm	+ioctl.test
 ioctl_ubi	+ioctl.test
 ioctl_ubi-success	+ioctl-success.sh -a24
 ioctl_uffdio	+ioctl.test
diff --git a/tests/ioctl_tiocm.c b/tests/ioctl_tiocm.c
new file mode 100644
index 000000000..402fce678
--- /dev/null
+++ b/tests/ioctl_tiocm.c
@@ -0,0 +1,96 @@
+/*
+ * Check decoding of ioctl TIOCM* commands.
+ *
+ * Copyright (c) 2020-2022 The strace developers.
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "tests.h"
+#include <errno.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+
+static const char *errstr;
+
+static int
+do_ioctl(kernel_ulong_t cmd, kernel_ulong_t arg)
+{
+	int rc = ioctl(-1, cmd, arg);
+	errstr = sprintrc(rc);
+	return rc;
+}
+
+static int
+do_ioctl_ptr(kernel_ulong_t cmd, const void *arg)
+{
+	return do_ioctl(cmd, (uintptr_t) arg);
+}
+
+int
+main(int argc, const char *argv[])
+{
+	static const struct {
+		uint32_t cmd;
+		const char *str;
+		bool on_enter;
+		bool on_exit;
+	} cmds[] = {
+		{ ARG_STR(TIOCMGET), false, true },
+		{ ARG_STR(TIOCMBIS), true, false },
+		{ ARG_STR(TIOCMBIC), true, false },
+		{ ARG_STR(TIOCMSET), true, false },
+	};
+
+	TAIL_ALLOC_OBJECT_CONST_PTR(unsigned int, p_flags);
+	const void *const efault = p_flags + 1;
+
+	for (size_t i = 0; i < ARRAY_SIZE(cmds); ++i) {
+		do_ioctl(cmds[i].cmd, 0);
+		printf("ioctl(-1, " XLAT_FMT ", NULL) = %s\n",
+		       XLAT_SEL(cmds[i].cmd, cmds[i].str), errstr);
+
+		do_ioctl_ptr(cmds[i].cmd, efault);
+		printf("ioctl(-1, " XLAT_FMT ", %p) = %s\n",
+		       XLAT_SEL(cmds[i].cmd, cmds[i].str),
+		       efault, errstr);
+
+#define VALID_FLAGS 0x1ff
+#define INVALID_FLAGS  0xfffffe00
+		*p_flags = INVALID_FLAGS;
+
+		if (cmds[i].on_enter) {
+			do_ioctl_ptr(cmds[i].cmd, p_flags);
+			printf("ioctl(-1, " XLAT_FMT ", [%s]) = %s\n",
+			       XLAT_SEL(cmds[i].cmd, cmds[i].str),
+			       XLAT_UNKNOWN(INVALID_FLAGS, "TIOCM_???"),
+			       errstr);
+
+			*p_flags = ~*p_flags;
+			do_ioctl_ptr(cmds[i].cmd, p_flags);
+			printf("ioctl(-1, " XLAT_FMT ", [%s]) = %s\n",
+			       XLAT_SEL(cmds[i].cmd, cmds[i].str),
+			       XLAT_KNOWN(VALID_FLAGS,
+					  "TIOCM_LE|"
+					  "TIOCM_DTR|"
+					  "TIOCM_RTS|"
+					  "TIOCM_ST|"
+					  "TIOCM_SR|"
+					  "TIOCM_CTS|"
+					  "TIOCM_CAR|"
+					  "TIOCM_RNG|"
+					  "TIOCM_DSR"),
+			       errstr);
+		} else if (cmds[i].on_exit) {
+			do_ioctl_ptr(cmds[i].cmd, p_flags);
+			printf("ioctl(-1, " XLAT_FMT ", %p) = %s\n",
+			       XLAT_SEL(cmds[i].cmd, cmds[i].str),
+			       p_flags, errstr);
+		}
+
+	}
+
+	puts("+++ exited with 0 +++");
+	return 0;
+}
diff --git a/tests/pure_executables.list b/tests/pure_executables.list
index 3c1317adb..c1b202ea9 100755
--- a/tests/pure_executables.list
+++ b/tests/pure_executables.list
@@ -241,6 +241,7 @@ ioctl_sg_io_v4
 ioctl_sock
 ioctl_sock_gifconf
 ioctl_tee
+ioctl_tiocm
 ioctl_ubi
 ioctl_uffdio
 ioctl_v4l2