linux: Do not call FatalError from xf86CloseConsole

FatalError ends up calling xf86CloseConsole itself, so calling FatalError
from within xf86CloseConsole is not a good idea.

Make switch_to log errors using xf86Msg(X_WARNING, ...) and return success
(or failure).

This makes switch_to match the other error checking done in xf86CloseConsole
which all logs warnings and continues.

Add checking of the return value in xf86OpenConsole and call
FatalError there when switch_to fails, to preserve the error-handling
behavior of xf86OpenConsole.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1269210
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
(cherry picked from commit 2092f12)

hw/xfree86/os-support/linux/lnx_init.c

@@ -62,18 +62,24 @@ drain_console(int fd, void *closure)
     }
 }
 
-static void
+static int
 switch_to(int vt, const char *from)
 {
     int ret;
 
     SYSCALL(ret = ioctl(xf86Info.consoleFd, VT_ACTIVATE, vt));
-    if (ret < 0)
-        FatalError("%s: VT_ACTIVATE failed: %s\n", from, strerror(errno));
+    if (ret < 0) {
+        xf86Msg(X_WARNING, "%s: VT_ACTIVATE failed: %s\n", from, strerror(errno));
+        return 0;
+    }
 
     SYSCALL(ret = ioctl(xf86Info.consoleFd, VT_WAITACTIVE, vt));
-    if (ret < 0)
-        FatalError("%s: VT_WAITACTIVE failed: %s\n", from, strerror(errno));
+    if (ret < 0) {
+        xf86Msg(X_WARNING, "%s: VT_WAITACTIVE failed: %s\n", from, strerror(errno));
+        return 0;
+    }
+
+    return 1;
 }
 
 #pragma GCC diagnostic push
@@ -208,7 +214,8 @@ xf86OpenConsole(void)
             /*
              * now get the VT.  This _must_ succeed, or else fail completely.
              */
-            switch_to(xf86Info.vtno, "xf86OpenConsole");
+            if (!switch_to(xf86Info.vtno, "xf86OpenConsole"))
+                FatalError("xf86OpenConsole: Switching VT failed\n");
 
             SYSCALL(ret = ioctl(xf86Info.consoleFd, VT_GETMODE, &VT));
             if (ret < 0)
@@ -269,7 +276,8 @@ xf86OpenConsole(void)
     else {                      /* serverGeneration != 1 */
         if (!xf86Info.ShareVTs && xf86Info.autoVTSwitch) {
             /* now get the VT */
-            switch_to(xf86Info.vtno, "xf86OpenConsole");
+            if (!switch_to(xf86Info.vtno, "xf86OpenConsole"))
+                FatalError("xf86OpenConsole: Switching VT failed\n");
         }
     }
 }