GUACAMOLE-559: Merge fix race condition in receipt of clipboard data by terminal.

src/common/clipboard.c

@@ -24,6 +24,7 @@
 #include <guacamole/protocol.h>
 #include <guacamole/stream.h>
 #include <guacamole/user.h>
+#include <pthread.h>
 #include <string.h>
 #include <stdlib.h>
 
@@ -37,6 +38,8 @@ guac_common_clipboard* guac_common_clipboard_alloc(int size) {
     clipboard->length = 0;
     clipboard->available = size;
 
+    pthread_mutex_init(&(clipboard->lock), NULL);
+
     return clipboard;
 
 }
@@ -108,18 +111,37 @@ static void* __send_user_clipboard(guac_user* user, void* data) {
 }
 
 void guac_common_clipboard_send(guac_common_clipboard* clipboard, guac_client* client) {
+
+    pthread_mutex_lock(&(clipboard->lock));
+
     guac_client_log(client, GUAC_LOG_DEBUG, "Broadcasting clipboard to all connected users.");
     guac_client_foreach_user(client, __send_user_clipboard, clipboard);
     guac_client_log(client, GUAC_LOG_DEBUG, "Broadcast of clipboard complete.");
+
+    pthread_mutex_unlock(&(clipboard->lock));
+
 }
 
-void guac_common_clipboard_reset(guac_common_clipboard* clipboard, const char* mimetype) {
+void guac_common_clipboard_reset(guac_common_clipboard* clipboard,
+        const char* mimetype) {
+
+    pthread_mutex_lock(&(clipboard->lock));
+
+    /* Clear clipboard contents */
     clipboard->length = 0;
-    strncpy(clipboard->mimetype, mimetype, sizeof(clipboard->mimetype)-1);
+
+    /* Assign given mimetype */
+    strncpy(clipboard->mimetype, mimetype, sizeof(clipboard->mimetype) - 1);
+    clipboard->mimetype[sizeof(clipboard->mimetype) - 1] = '\0';
+
+    pthread_mutex_unlock(&(clipboard->lock));
+
 }
 
 void guac_common_clipboard_append(guac_common_clipboard* clipboard, const char* data, int length) {
 
+    pthread_mutex_lock(&(clipboard->lock));
+
     /* Truncate data to available length */
     int remaining = clipboard->available - clipboard->length;
     if (remaining < length)
@@ -131,5 +153,7 @@ void guac_common_clipboard_append(guac_common_clipboard* clipboard, const char*
     /* Update length */
     clipboard->length += length;
 
+    pthread_mutex_unlock(&(clipboard->lock));
+
 }
 

src/common/common/clipboard.h

@@ -23,6 +23,7 @@
 #include "config.h"
 
 #include <guacamole/client.h>
+#include <pthread.h>
 
 /**
  * The maximum number of bytes to send in an individual blob when
@@ -35,6 +36,13 @@
  */
 typedef struct guac_common_clipboard {
 
+    /**
+     * Lock which restricts simultaneous access to the clipboard, guaranteeing
+     * ordered modifications to the clipboard and that changes to the clipboard
+     * are not allowed while the clipboard is being broadcast to all users.
+     */
+    pthread_mutex_t lock;
+
     /**
      * The mimetype of the contained clipboard data.
      */

src/protocols/ssh/client.c

@@ -20,6 +20,7 @@
 #include "config.h"
 
 #include "client.h"
+#include "common/clipboard.h"
 #include "common/recording.h"
 #include "common-ssh/sftp.h"
 #include "ssh.h"
@@ -42,6 +43,9 @@ int guac_client_init(guac_client* client) {
     guac_ssh_client* ssh_client = calloc(1, sizeof(guac_ssh_client));
     client->data = ssh_client;
 
+    /* Init clipboard */
+    ssh_client->clipboard = guac_common_clipboard_alloc(GUAC_SSH_CLIPBOARD_MAX_LENGTH);
+
     /* Set handlers */
     client->join_handler = guac_ssh_user_join_handler;
     client->free_handler = guac_ssh_client_free_handler;
@@ -106,6 +110,7 @@ int guac_ssh_client_free_handler(guac_client* client) {
         guac_ssh_settings_free(ssh_client->settings);
 
     /* Free client structure */
+    guac_common_clipboard_free(ssh_client->clipboard);
     free(ssh_client);
 
     guac_common_ssh_uninit();

src/protocols/ssh/client.h

@@ -22,6 +22,11 @@
 
 #include <guacamole/client.h>
 
+/**
+ * The maximum number of bytes to allow within the clipboard.
+ */
+#define GUAC_SSH_CLIPBOARD_MAX_LENGTH 262144
+
 /**
  * Handler which is invoked when the SSH client needs to be disconnected (if
  * connected) and freed. This can happen if initialization fails, or all users

src/protocols/ssh/clipboard.c

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "clipboard.h"
+#include "common/clipboard.h"
 #include "ssh.h"
 #include "terminal/terminal.h"
 
@@ -32,7 +33,7 @@ int guac_ssh_clipboard_handler(guac_user* user, guac_stream* stream,
     /* Clear clipboard and prepare for new data */
     guac_client* client = user->client;
     guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
-    guac_terminal_clipboard_reset(ssh_client->term, mimetype);
+    guac_common_clipboard_reset(ssh_client->clipboard, mimetype);
 
     /* Set handlers for clipboard stream */
     stream->blob_handler = guac_ssh_clipboard_blob_handler;
@@ -47,7 +48,7 @@ int guac_ssh_clipboard_blob_handler(guac_user* user, guac_stream* stream,
     /* Append new data */
     guac_client* client = user->client;
     guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
-    guac_terminal_clipboard_append(ssh_client->term, data, length);
+    guac_common_clipboard_append(ssh_client->clipboard, data, length);
 
     return 0;
 }

src/protocols/ssh/ssh.c

@@ -206,7 +206,7 @@ void* ssh_client_thread(void* data) {
     }
 
     /* Create terminal */
-    ssh_client->term = guac_terminal_create(client,
+    ssh_client->term = guac_terminal_create(client, ssh_client->clipboard,
             settings->font_name, settings->font_size,
             settings->resolution, settings->width, settings->height,
             settings->color_scheme, settings->backspace);

src/protocols/ssh/ssh.h

@@ -22,6 +22,7 @@
 
 #include "config.h"
 
+#include "common/clipboard.h"
 #include "common/recording.h"
 #include "common-ssh/sftp.h"
 #include "common-ssh/ssh.h"
@@ -89,6 +90,11 @@ typedef struct guac_ssh_client {
      */
     pthread_mutex_t term_channel_lock;
 
+    /**
+     * The current clipboard contents.
+     */
+    guac_common_clipboard* clipboard;
+
     /**
      * The terminal which will render all output from the SSH client.
      */

src/protocols/telnet/client.c

@@ -42,6 +42,9 @@ int guac_client_init(guac_client* client) {
     guac_telnet_client* telnet_client = calloc(1, sizeof(guac_telnet_client));
     client->data = telnet_client;
 
+    /* Init clipboard */
+    telnet_client->clipboard = guac_common_clipboard_alloc(GUAC_TELNET_CLIPBOARD_MAX_LENGTH);
+
     /* Init telnet client */
     telnet_client->socket_fd = -1;
     telnet_client->naws_enabled = 0;
@@ -89,6 +92,7 @@ int guac_telnet_client_free_handler(guac_client* client) {
     if (telnet_client->settings != NULL)
         guac_telnet_settings_free(telnet_client->settings);
 
+    guac_common_clipboard_free(telnet_client->clipboard);
     free(telnet_client);
     return 0;
 

src/protocols/telnet/client.h

@@ -29,6 +29,11 @@
 
 #include <libtelnet.h>
 
+/**
+ * The maximum number of bytes to allow within the clipboard.
+ */
+#define GUAC_TELNET_CLIPBOARD_MAX_LENGTH 262144
+
 /**
  * Free handler. Required by libguac and called when the guac_client is
  * disconnected and must be cleaned up.

src/protocols/telnet/clipboard.c

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "clipboard.h"
+#include "common/clipboard.h"
 #include "telnet.h"
 #include "terminal/terminal.h"
 
@@ -32,7 +33,7 @@ int guac_telnet_clipboard_handler(guac_user* user, guac_stream* stream,
     /* Clear clipboard and prepare for new data */
     guac_client* client = user->client;
     guac_telnet_client* telnet_client = (guac_telnet_client*) client->data;
-    guac_terminal_clipboard_reset(telnet_client->term, mimetype);
+    guac_common_clipboard_reset(telnet_client->clipboard, mimetype);
 
     /* Set handlers for clipboard stream */
     stream->blob_handler = guac_telnet_clipboard_blob_handler;
@@ -47,7 +48,7 @@ int guac_telnet_clipboard_blob_handler(guac_user* user, guac_stream* stream,
     /* Append new data */
     guac_client* client = user->client;
     guac_telnet_client* telnet_client = (guac_telnet_client*) client->data;
-    guac_terminal_clipboard_append(telnet_client->term, data, length);
+    guac_common_clipboard_append(telnet_client->clipboard, data, length);
 
     return 0;
 }

src/protocols/telnet/telnet.c

@@ -478,6 +478,7 @@ void* guac_telnet_client_thread(void* data) {
 
     /* Create terminal */
     telnet_client->term = guac_terminal_create(client,
+            telnet_client->clipboard,
             settings->font_name, settings->font_size,
             settings->resolution, settings->width, settings->height,
             settings->color_scheme, settings->backspace);

src/protocols/telnet/telnet.h

@@ -21,6 +21,7 @@
 #define GUAC_TELNET_H
 
 #include "config.h"
+#include "common/clipboard.h"
 #include "common/recording.h"
 #include "settings.h"
 #include "terminal/terminal.h"
@@ -66,6 +67,11 @@ typedef struct guac_telnet_client {
      */
     int echo_enabled;
 
+    /**
+     * The current clipboard contents.
+     */
+    guac_common_clipboard* clipboard;
+
     /**
      * The terminal which will render all output from the telnet client.
      */

src/terminal/terminal.c

@@ -502,6 +502,7 @@ static void guac_terminal_parse_color_scheme(guac_client* client,
 }
 
 guac_terminal* guac_terminal_create(guac_client* client,
+        guac_common_clipboard* clipboard,
         const char* font_name, int font_size, int dpi,
         int width, int height, const char* color_scheme,
         const int backspace) {
@@ -582,6 +583,7 @@ guac_terminal* guac_terminal_create(guac_client* client,
     /* Init terminal state */
     term->current_attributes = default_char.attributes;
     term->default_char = default_char;
+    term->clipboard = clipboard;
 
     /* Set pixel size */
     term->width = width;
@@ -632,9 +634,6 @@ guac_terminal* guac_terminal_create(guac_client* client,
     term->current_cursor = GUAC_TERMINAL_CURSOR_BLANK;
     guac_common_cursor_set_blank(term->cursor);
 
-    /* Allocate clipboard */
-    term->clipboard = guac_common_clipboard_alloc(GUAC_TERMINAL_CLIPBOARD_MAX_LENGTH);
-
     /* Start terminal thread */
     if (pthread_create(&(term->thread), NULL,
                 guac_terminal_thread, (void*) term)) {
@@ -682,9 +681,6 @@ void guac_terminal_free(guac_terminal* term) {
     /* Free buffer */
     guac_terminal_buffer_free(term->buffer);
 
-    /* Free clipboard */
-    guac_common_clipboard_free(term->clipboard);
-
     /* Free scrollbar */
     guac_terminal_scrollbar_free(term->scrollbar);
 
@@ -2028,14 +2024,6 @@ void guac_terminal_scroll_handler(guac_terminal_scrollbar* scrollbar, int value)
 
 }
 
-void guac_terminal_clipboard_reset(guac_terminal* term, const char* mimetype) {
-    guac_common_clipboard_reset(term->clipboard, mimetype);
-}
-
-void guac_terminal_clipboard_append(guac_terminal* term, const void* data, int length) {
-    guac_common_clipboard_append(term->clipboard, data, length);
-}
-
 int guac_terminal_sendf(guac_terminal* term, const char* format, ...) {
 
     int written;

src/terminal/terminal/terminal.h

@@ -58,11 +58,6 @@
  */
 #define GUAC_TERMINAL_WHEEL_SCROLL_AMOUNT 3
 
-/**
- * The maximum number of bytes to allow within the clipboard.
- */
-#define GUAC_TERMINAL_CLIPBOARD_MAX_LENGTH 262144
-
 /**
  * The name of the color scheme having black foreground and white background.
  */
@@ -443,7 +438,10 @@ struct guac_terminal {
     guac_terminal_cursor_type current_cursor;
 
     /**
-     * The current contents of the clipboard.
+     * The current contents of the clipboard. This clipboard instance is
+     * maintained externally (will not be freed when this terminal is freed)
+     * and will be updated both internally by the terminal and externally
+     * through received clipboard instructions.
      */
     guac_common_clipboard* clipboard;
 
@@ -461,6 +459,13 @@ struct guac_terminal {
  * @param client
  *     The client to which the terminal will be rendered.
  *
+ * @param clipboard
+ *     The guac_common_clipboard which will contain the current clipboard
+ *     state. It is expected that this clipboard instance will be updated
+ *     both internally by the terminal and externally through received
+ *     clipboard instructions. This clipboard will not be automatically
+ *     freed when this terminal is freed.
+ *
  * @param font_name
  *     The name of the font to use when rendering glyphs.
  *
@@ -493,6 +498,7 @@ struct guac_terminal {
  *     which renders all text to the given client.
  */
 guac_terminal* guac_terminal_create(guac_client* client,
+        guac_common_clipboard* clipboard,
         const char* font_name, int font_size, int dpi,
         int width, int height, const char* color_scheme,
         const int backspace);
@@ -592,17 +598,6 @@ int guac_terminal_send_mouse(guac_terminal* term, guac_user* user,
  */
 void guac_terminal_scroll_handler(guac_terminal_scrollbar* scrollbar, int value);
 
-/**
- * Clears the current clipboard contents and sets the mimetype for future
- * contents.
- */
-void guac_terminal_clipboard_reset(guac_terminal* term, const char* mimetype);
-
-/**
- * Appends the given data to the current clipboard.
- */
-void guac_terminal_clipboard_append(guac_terminal* term, const void* data, int length);
-
 /**
  * Replicates the current display state to a user that has just joined the
  * connection. All instructions necessary to replicate state are sent over the