Retry VT_WAITACTIVE ioctl if interrupted

My personal use-case that triggers the problem:
physlock is launched by the XFCE Power Manager daemon when the system is
suspended. What happens is that, sometimes, the WAITACTIVE ioctl is
issued just before the system goes to sleep. When the system resumes,
the ioctl returns with errno=EINTR (aka interrupted system call),
therefore physlock exits.

Retrying the ioctl is enough to solve the problem.

vt.c

@@ -63,6 +63,8 @@ void get_current_vt(int *nr) {
 }
 
 void acquire_new_vt(vt_t *vt) {
+	int ret;
+
 	vt->nr = -1;
 	vt->ios = NULL;
 	vt->fd = -1;
@@ -78,9 +80,11 @@ void acquire_new_vt(vt_t *vt) {
 		die("could not open %s: %s", filename, strerror(errno));
 	vt->fd = fileno(vt->ios);
 
-	if (ioctl(fd, VT_ACTIVATE, vt->nr) == -1 ||
-			ioctl(fd, VT_WAITACTIVE, vt->nr) == -1)
+	if (ioctl(fd, VT_ACTIVATE, vt->nr) == -1)
 		die("could not activate console # %d: %s", vt->nr, strerror(errno));
+	while ((ret = ioctl(fd, VT_WAITACTIVE, vt->nr)) == -1 && errno == EINTR);
+	if (ret == -1)
+		die("could not wait for console # %d: %s", vt->nr, strerror(errno));
 
 	tcgetattr(vt->fd, &vt->term);
 	vt->rlflag = vt->term.c_lflag;
@@ -97,13 +101,18 @@ void reopen_vt(vt_t *vt) {
 }
 
 void release_vt(vt_t *vt, int nr) {
+	int ret;
+
 	if (fd < 0)
 		die("release_vt() called without vt_init()");
 	if (nr <= 0)
 		die("release_vt() called with invalid argument");
-	if (ioctl(fd, VT_ACTIVATE, nr) == -1 ||
-			ioctl(fd, VT_WAITACTIVE, nr) == -1)
+
+	if (ioctl(fd, VT_ACTIVATE, nr) == -1)
 		die("could not activate console # %d: %s", nr, strerror(errno));
+	while ((ret = ioctl(fd, VT_WAITACTIVE, nr)) == -1 && errno == EINTR);
+	if (ret == -1)
+		die("could not wait for console # %d: %s", nr, strerror(errno));
 
 	if (vt->ios != NULL) {
 		fclose(vt->ios);