Buffer overruns are embarassing (even if caused by user error), so assert

[u/mdw/putty] / x11fwd.c

diff --git a/x11fwd.c b/x11fwd.c
index 8b045f3..17ab3a2 100644 (file)
--- a/x11fwd.c
+++ b/x11fwd.c
@@ -1,3 +1,7 @@
+/*
+ * Platform-independent bits of X11 forwarding.
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
@@ -174,6 +178,12 @@ static char *x11_verify(unsigned long peer_ip, int peer_port,
     return NULL;
 }
 
+static void x11_log(Plug p, int type, SockAddr addr, int port,
+                   const char *error_msg, int error_code)
+{
+    /* We have no interface to the logging module here, so we drop these. */
+}
+
 static int x11_closing(Plug plug, const char *error_msg, int error_code,
                       int calling_back)
 {
@@ -226,6 +236,25 @@ int x11_get_screen_number(char *display)
     return atoi(display + n + 1);
 }
 
+/* Find the right display, returns an allocated string */
+char *x11_display(const char *display) {
+    char *ret;
+    if(!display || !*display) {
+       /* try to find platform-specific local display */
+       if((ret = platform_get_x_display())==0)
+           /* plausible default for all platforms */
+           ret = dupstr(":0");
+    } else
+       ret = dupstr(display);
+    if(ret[0] == ':') {
+       /* no transport specified, use whatever we think is best */
+       char *s = dupcat(platform_x11_best_transport, ret, (char *)0);
+       sfree(ret);
+       return s;
+    } else
+       return ret;
+}
+
 /*
  * Called to set up the raw connection.
  * 
@@ -236,6 +265,7 @@ const char *x11_init(Socket * s, char *display, void *c, void *auth,
                     const char *peeraddr, int peerport, const Config *cfg)
 {
     static const struct plug_function_table fn_table = {
+       x11_log,
        x11_closing,
        x11_receive,
        x11_sent,
@@ -250,36 +280,39 @@ const char *x11_init(Socket * s, char *display, void *c, void *auth,
     int n, displaynum;
     struct X11Private *pr;
 
+    /* default display */
+    display = x11_display(display);
     /*
      * Split up display name into host and display-number parts.
      */
     n = strcspn(display, ":");
+    assert(n != 0);            /* x11_display() promises this */
     if (display[n])
        displaynum = atoi(display + n + 1);
     else
        displaynum = 0;                /* sensible default */
     if (n > sizeof(host) - 1)
        n = sizeof(host) - 1;
-    if (n > 0) {
-       strncpy(host, display, n);
-       host[n] = '\0';
+    strncpy(host, display, n);
+    host[n] = '\0';
+    sfree(display);
+    
+    if(!strcmp(host, "unix")) {
+       /* use AF_UNIX sockets (doesn't make sense on all platforms) */
+       addr = platform_get_x11_unix_address(displaynum,
+                                            &dummy_realhost);
+       port = 0;               /* to show we are not confused */
     } else {
+       port = 6000 + displaynum;
+       
        /*
-        * Local display numbers, particularly on Unix, often omit
-        * the display part completely.
+        * Try to find host.
         */
-       strcpy(host, "localhost");
-    }
-
-    port = 6000 + displaynum;
-
-    /*
-     * Try to find host.
-     */
-    addr = name_lookup(host, port, &dummy_realhost, cfg);
-    if ((err = sk_addr_error(addr)) != NULL) {
-       sk_addr_free(addr);
-       return err;
+       addr = name_lookup(host, port, &dummy_realhost, cfg, ADDRTYPE_UNSPEC);
+       if ((err = sk_addr_error(addr)) != NULL) {
+           sk_addr_free(addr);
+           return err;
+       }
     }
 
     /*
@@ -295,7 +328,7 @@ const char *x11_init(Socket * s, char *display, void *c, void *auth,
     pr->c = c;
 
     pr->s = *s = new_connection(addr, dummy_realhost, port,
-                               0, 1, 0, (Plug) pr, cfg);
+                               0, 1, 0, 0, (Plug) pr, cfg);
     if ((err = sk_socket_error(*s)) != NULL) {
        sfree(pr);
        return err;