Replace X11 display number with a display string

As far as possible, use of the X11 display number is kept to
X11-specific routines. This is to make it easier to restructure
the code to add non-X11 display support.

common/string_calls.c

@@ -162,8 +162,8 @@ g_text2bool(const char *s)
 }
 
 /*****************************************************************************/
-int
-g_get_display_num_from_display(const char *display_text)
+static int
+get_display_num_from_display(const char *display_text)
 {
     int rv = -1;
     const char *p;
@@ -191,6 +191,70 @@ g_get_display_num_from_display(const char *display_text)
     return rv;
 }
 
+/*****************************************************************************/
+int
+g_get_display_string_from_x11_display(int display_num,
+                                      char buff[], unsigned int bufflen)
+{
+    unsigned int res = g_snprintf(buff, bufflen, "X11-%d", display_num);
+    return (res >= bufflen) ? -1 : 0;
+}
+
+
+/*****************************************************************************/
+int
+g_get_x11_display_from_display_string(const char *display_str)
+{
+    int result = -1;
+    if (display_str != NULL)
+    {
+        if (display_str[0] == 'X' && display_str[1] == '1' &&
+                display_str[2] == '1' && display_str[3] == '-' &&
+                isdigit(display_str[4]))
+        {
+            result = g_atoi(display_str + 4);
+        }
+    }
+
+    return result;
+}
+
+/*****************************************************************************/
+int
+g_get_display_string(char buff[], unsigned int bufflen)
+{
+    const char *str;
+    const char *p = NULL;
+    int rv = 0;
+
+    if ((str = g_getenv("WAYLAND_DISPLAY")) != NULL)
+    {
+        // Return the unqualified part of the name
+        p = strrchr(str, '/');
+        p = (p != NULL) ? (p + 1) : str;
+        strlcpy(buff, p, bufflen);
+    }
+    else if ((str = g_getenv("DISPLAY")) != NULL)
+    {
+        int n = get_display_num_from_display(str);
+
+        if (n >= 0)
+        {
+            g_snprintf(buff, bufflen, "X11-%d", n);
+        }
+        else
+        {
+            rv = g_get_display_string_from_x11_display(n, buff, bufflen);
+        }
+    }
+    else
+    {
+        rv = -1;
+    }
+
+    return rv;
+}
+
 /*****************************************************************************/
 /* returns length of text */
 int

common/string_calls.h

@@ -190,14 +190,37 @@ char *
 g_bytes_to_hexdump(const char *src, int len);
 
 /**
- * Extracts the display number from an X11 display string
+ * Converts an X11 display number to a display string
  *
- * @param display_text Display string (i.e. g_getenv("DISPLAY"))
- *
- * @result <0 if the string could not be parsed, or >=0 for a display number
+ * @param display_num X11 display unmber
+ * @param buff Buffer for result
+ * @param bufflen size of above
+ * @return != 0 if the result doesn't fit
  */
 int
-g_get_display_num_from_display(const char *display_text);
+g_get_display_string_from_x11_display(int display_num,
+                                      char buff[], unsigned int bufflen);
+/**
+ * Converts a display string to an X11 display number
+ *
+ * @param display_str Display string
+ * @return X11 display number, or -1 if the display string isn't X11
+ */
+int
+g_get_x11_display_from_display_string(const char *display_str);
+
+/**
+ * Extracts the display string from either DISPLAY or WAYLAND_DISPLAY
+ *
+ * @param buff Buffer for result
+ * @param bufflen Length of above buffer
+ *
+ * Returned buffer will be (e.g.) "X11-10" for X11 or "wayland-1" for Wayland
+ *
+ * @result != 0 if the string could not be found or parsed
+ */
+int
+g_get_display_string(char buff[], unsigned int bufflen);
 
 /**
  * Converts a bitmask into a string for output purposes

common/xrdp_constants.h

@@ -49,6 +49,12 @@
  **/
 #define MAX_XRDP_INSTANCE_NAMELEN 80
 
+/**
+ * Max length of buffer containing a Wayland or X11 display
+ * name
+ **/
+#define MAX_DISPLAY_NAME_SIZE 32
+
 /**
  * Size of buffer including terminator for a socket description, as
  * returned by g_sck_get_peer_description()

common/xrdp_sockets.h

@@ -45,13 +45,13 @@
 #define SCP_LISTEN_PORT_BASE_STR   "sesman.socket"
 
 /* names of socket files within XRDP_SOCKET_PATH, qualified by
- * display number */
-#define XRDP_CHANSRV_BASE_STR      "xrdp_chansrv_socket_%d"
-#define CHANSRV_PORT_OUT_BASE_STR  "xrdp_chansrv_audio_out_socket_%d"
-#define CHANSRV_PORT_IN_BASE_STR   "xrdp_chansrv_audio_in_socket_%d"
-#define CHANSRV_API_BASE_STR       "xrdpapi_%d"
-#define XRDP_X11RDP_BASE_STR       "xrdp_display_%d"
-#define XRDP_DISCONNECT_BASE_STR   "xrdp_disconnect_display_%d"
+ * display name */
+#define XRDP_CHANSRV_BASE_STR      "xrdp_chansrv_socket_%s"
+#define CHANSRV_PORT_OUT_BASE_STR  "xrdp_chansrv_audio_out_socket_%s"
+#define CHANSRV_PORT_IN_BASE_STR   "xrdp_chansrv_audio_in_socket_%s"
+#define CHANSRV_API_BASE_STR       "xrdpapi_%s"
+#define XRDP_X11RDP_BASE_STR       "xrdp_display_%s"
+#define XRDP_DISCONNECT_BASE_STR   "xrdp_disconnect_display_%s"
 
 /* fullpath declarations */
 #define XRDP_CHANSRV_STR      XRDP_SOCKET_PATH "/" XRDP_CHANSRV_BASE_STR