uvtd: vt: implement VT_GETMODE/SETMODE ioctl state-tracking

These ioctls are used to retrieve and set the VT-mode. That is, the
signals and PID information that correspond to the VT controlling process.
It is notified whenever the VT gets active/inactive so it can react to it
or prevent/acknowledge it.

This doesn't implement the signal-sending logic, yet. It only implements
state-tracking.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>

3 files changed, 42 insertions, 5 deletions

diff --git a/src/uvt.h b/src/uvt.h
index a69dd6f..e767005 100644
--- a/src/uvt.h
+++ b/src/uvt.h
@@ -108,7 +108,8 @@ struct uvt_vt_ops {
 	int (*ioctl_VT_GETSTATE) (void *data, struct vt_stat *arg);
 	int (*ioctl_VT_OPENQRY) (void *data, unsigned int *arg);
 	int (*ioctl_VT_GETMODE) (void *data, struct vt_mode *arg);
-	int (*ioctl_VT_SETMODE) (void *data, const struct vt_mode *arg);
+	int (*ioctl_VT_SETMODE) (void *data, const struct vt_mode *arg,
+				 pid_t pid);
 	int (*ioctl_VT_RELDISP) (void *data, unsigned long arg);
 	int (*ioctl_KDGETMODE) (void *data, unsigned int *arg);
 	int (*ioctl_KDSETMODE) (void *data, unsigned int arg);
diff --git a/src/uvt_client.c b/src/uvt_client.c
index d31a35b..574001e 100644
--- a/src/uvt_client.c
+++ b/src/uvt_client.c
@@ -972,7 +972,8 @@ void uvt_client_ll_ioctl(fuse_req_t req, int cmd, void *arg,
 			fuse_reply_err(req, EOPNOTSUPP);
 		} else {
 			ret = client->vt->ioctl_VT_SETMODE(client->vt_data,
-						(const struct vt_mode*)in_buf);
+						(const struct vt_mode*)in_buf,
+						fuse_req_ctx(req)->pid);
 			if (ret)
 				fuse_reply_err(req, abs(ret));
 			else
diff --git a/src/uvtd_vt.c b/src/uvtd_vt.c
index 18e4503..cc121a0 100644
--- a/src/uvtd_vt.c
+++ b/src/uvtd_vt.c
@@ -33,6 +33,7 @@
 #include <inttypes.h>
 #include <linux/kd.h>
 #include <linux/vt.h>
+#include <signal.h>
 #include <stdlib.h>
 #include <string.h>
 #include <termio.h>
@@ -55,6 +56,8 @@ struct uvtd_vt {
 
 	unsigned int mode;
 	unsigned int kbmode;
+	struct vt_mode vtmode;
+	pid_t vtpid;
 };
 
 static void vt_hup(struct uvtd_vt *vt)
@@ -107,6 +110,7 @@ int uvtd_vt_new(struct uvtd_vt **out, struct uvt_ctx *uctx, unsigned int id,
 	vt->is_legacy = is_legacy;
 	vt->mode = KD_TEXT;
 	vt->kbmode = K_UNICODE;
+	vt->vtmode.mode = VT_AUTO;
 
 	ret = shl_hook_new(&vt->hook);
 	if (ret)
@@ -214,12 +218,43 @@ static int vt_ioctl_VT_OPENQRY(void *data, unsigned int *arg)
 
 static int vt_ioctl_VT_GETMODE(void *data, struct vt_mode *arg)
 {
-	return -EINVAL;
+	struct uvtd_vt *vt = data;
+
+	memcpy(arg, &vt->vtmode, sizeof(*arg));
+	return 0;
 }
 
-static int vt_ioctl_VT_SETMODE(void *data, const struct vt_mode *arg)
+static int vt_ioctl_VT_SETMODE(void *data, const struct vt_mode *arg,
+			       pid_t pid)
 {
-	return -EINVAL;
+	struct uvtd_vt *vt = data;
+
+	/* TODO: implement waitv logic (hang on write if not active) */
+	if (arg->waitv)
+		return -EOPNOTSUPP;
+
+	if (arg->frsig)
+		return -EINVAL;
+	if (arg->relsig > SIGRTMAX || arg->relsig < 0)
+		return -EINVAL;
+	if (arg->acqsig > SIGRTMAX || arg->acqsig < 0)
+		return -EINVAL;
+
+	switch (arg->mode) {
+	case VT_AUTO:
+		if (arg->acqsig || arg->relsig)
+			return -EINVAL;
+		vt->vtpid = 0;
+		break;
+	case VT_PROCESS:
+		vt->vtpid = pid;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	memcpy(&vt->vtmode, arg, sizeof(*arg));
+	return 0;
 }
 
 static int vt_ioctl_VT_RELDISP(void *data, unsigned long arg)