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ioctl: Forward standard termios calls to real pty #279

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19 changes: 18 additions & 1 deletion src/umockdev-ioctl.vala
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Original file line number Diff line number Diff line change
Expand Up @@ -568,6 +568,9 @@ public class IoctlClient : GLib.Object {
}

if (!handled && args[0] == 1) {
/* No specific handler for this ioctl. First try stateless ioctls
* (like USB ioctls), then fall back to executing on the real fd
* for terminal ioctls on PTY-backed devices. */
IoctlTree.Tree tree = null;
IoctlData? data = null;
ulong size = IoctlTree.data_size_by_id(_request);
Expand All @@ -594,7 +597,21 @@ public class IoctlClient : GLib.Object {
my_errno = Posix.errno;
Posix.errno = 0;

if (ret != -1) {
/* For termios ioctls (TCGETS, etc.), try executing on the real fd (PTY).
* Check the ioctl number (low byte) and type to identify termios
* ioctls, but exclude non-termios ioctls like FIONREAD (0x541B). */
ulong nr = _request & 0xFF;
bool is_termios_ioctl = ((char) type == 'T') &&
((nr >= 0x01 && nr <= 0x08) || // TCGETS, TCSETS, etc.
(nr >= 0x13 && nr <= 0x16) || // TCGETS2, TCSETS2, TCSETSW2, TCSETSF2
(nr >= 0x2A && nr <= 0x2C)); // TCSETS2 (with size)
if (ret == -1 && my_errno == Posix.ENOTTY && is_termios_ioctl) {
try {
ret = execute(out my_errno);
} catch (IOError e) {
/* If real ioctl also fails, keep the ENOTTY error */
}
} else if (ret != -1) {
my_errno = 0;
}

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20 changes: 20 additions & 0 deletions tests/test-umockdev-vala.vala
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Original file line number Diff line number Diff line change
Expand Up @@ -279,6 +279,26 @@ E: SUBSYSTEM=usb
Posix.close (fd);
Posix.errno = 0;

// Test that TCGETS2 works on an emulated TTY device (backed by a real PTY)
tb_add_from_string (tb, """P: /devices/serial/ttyTest
N: ttyTest
E: DEVNAME=/dev/ttyTest
E: SUBSYSTEM=tty
""");

fd = Posix.open ("/dev/ttyTest", Posix.O_RDWR | Posix.O_NONBLOCK, 0);
assert_cmpint (fd, CompareOperator.GE, 0);
Posix.errno = 0;
// Note: We can't use the Linux.Termios.TCGETS2 constant here due to a Vala compiler limitation.
// It is defined in sys/ioctl.h using _IOR(struct termios2), and Vala tries to apply
// sizeof() to the incomplete termios2 struct.
long tio_data = 0;
assert_cmpint (Posix.ioctl (fd, 0x5413, &tio_data), CompareOperator.EQ, 0);
assert_cmpint (Posix.errno, CompareOperator.EQ, 0);

Posix.close (fd);
Posix.errno = 0;

// unknown ioctls do work on non-emulated devices
fd = Posix.open ("/dev/stdout", Posix.O_WRONLY, 0);
assert_cmpint (fd, CompareOperator.GE, 0);
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