GUACAMOLE-610: Merge add support for changing scrollback buffer size.

bin/guacctl

@@ -90,6 +90,18 @@ send_close_pipe_stream() {
     printf "\033]482203;\007"
 }
 
+##
+## Sends the Guacamole-specific console code for resizing the scrollback
+## buffer.
+##
+## @param ROWS
+##     The number of rows that the scrollback buffer should contain.
+##
+send_resize_scrollback() {
+    ROWS="$1"
+    printf "\033]482204;%s\007" "$ROWS"
+}
+
 ##
 ## Prints the given error text to STDERR.
 ##
@@ -115,6 +127,8 @@ Usage: guacctl [OPTION] [FILE or NAME]...
                            name.
     -c, --close-pipe       close any existing pipe stream and redirect output
                            back to the terminal emulator.
+    -S, --scrollback       request that the scrollback buffer be limited to the
+                           given number of rows.
 END
 }
 
@@ -243,6 +257,39 @@ close_pipe_stream() {
 
 }
 
+##
+## Resizes the scrollback buffer to the given number of rows.
+##
+## @param ...
+##     The number of rows that should be contained within the scrollback
+##     buffer, as provided to guacctl.
+##
+resize_scrollback() {
+
+    #
+    # Validate arguments
+    #
+
+    if [ $# -lt 1 ]; then
+        error "No row count specified."
+        return;
+    fi
+
+    if [ $# -gt 1 ]; then
+        error "Only one row count may be given."
+        return;
+    fi
+
+    #
+    # Send code for resizing scrollback
+    #
+
+    ROWS="$1"
+    send_resize_scrollback "$ROWS"
+
+}
+
+
 #
 # Get script name
 #
@@ -300,6 +347,15 @@ case "$1" in
         close_pipe_stream "$@"
         ;;
 
+    #
+    # Resize scrollback
+    #
+
+    "--scrollback"|"-S")
+        shift
+        resize_scrollback "$@"
+        ;;
+
     #
     # Show usage info if options are invalid
     #

src/protocols/ssh/settings.c

@@ -59,6 +59,7 @@ const char* GUAC_SSH_CLIENT_ARGS[] = {
     "server-alive-interval",
     "backspace",
     "terminal-type",
+    "scrollback",
     NULL
 };
 
@@ -232,6 +233,11 @@ enum SSH_ARGS_IDX {
      */
     IDX_TERMINAL_TYPE,
 
+    /**
+     * The maximum size of the scrollback buffer in rows.
+     */
+    IDX_SCROLLBACK,
+
     SSH_ARGS_COUNT
 };
 
@@ -274,6 +280,11 @@ guac_ssh_settings* guac_ssh_parse_args(guac_user* user,
         guac_user_parse_args_string(user, GUAC_SSH_CLIENT_ARGS, argv,
                 IDX_PASSPHRASE, NULL);
 
+    /* Read maximum scrollback size */
+    settings->max_scrollback =
+        guac_user_parse_args_int(user, GUAC_SSH_CLIENT_ARGS, argv,
+                IDX_SCROLLBACK, GUAC_SSH_DEFAULT_MAX_SCROLLBACK);
+
     /* Read font name */
     settings->font_name =
         guac_user_parse_args_string(user, GUAC_SSH_CLIENT_ARGS, argv,

src/protocols/ssh/settings.h

@@ -58,6 +58,11 @@
  */
 #define GUAC_SSH_DEFAULT_POLL_TIMEOUT 1000
 
+/**
+ * The default maximum scrollback size in rows.
+ */
+#define GUAC_SSH_DEFAULT_MAX_SCROLLBACK 1000
+
 /**
  * Settings for the SSH connection. The values for this structure are parsed
  * from the arguments given during the Guacamole protocol handshake using the
@@ -115,6 +120,11 @@ typedef struct guac_ssh_settings {
      */
     char* command;
 
+    /**
+     * The maximum size of the scrollback buffer in rows.
+     */
+    int max_scrollback;
+
     /**
      * The name of the font to use for display rendering.
      */

src/protocols/ssh/ssh.c

@@ -207,7 +207,7 @@ void* ssh_client_thread(void* data) {
 
     /* Create terminal */
     ssh_client->term = guac_terminal_create(client, ssh_client->clipboard,
-            settings->font_name, settings->font_size,
+            settings->max_scrollback, settings->font_name, settings->font_size,
             settings->resolution, settings->width, settings->height,
             settings->color_scheme, settings->backspace);
 

src/protocols/telnet/settings.c

@@ -52,6 +52,7 @@ const char* GUAC_TELNET_CLIENT_ARGS[] = {
     "read-only",
     "backspace",
     "terminal-type",
+    "scrollback",
     NULL
 };
 
@@ -190,6 +191,11 @@ enum TELNET_ARGS_IDX {
      */
     IDX_TERMINAL_TYPE,
 
+    /**
+     * The maximum size of the scrollback buffer in rows.
+     */
+    IDX_SCROLLBACK,
+
     TELNET_ARGS_COUNT
 };
 
@@ -274,6 +280,11 @@ guac_telnet_settings* guac_telnet_parse_args(guac_user* user,
         guac_user_parse_args_boolean(user, GUAC_TELNET_CLIENT_ARGS, argv,
                 IDX_READ_ONLY, false);
 
+    /* Read maximum scrollback size */
+    settings->max_scrollback =
+        guac_user_parse_args_int(user, GUAC_TELNET_CLIENT_ARGS, argv,
+                IDX_SCROLLBACK, GUAC_TELNET_DEFAULT_MAX_SCROLLBACK);
+
     /* Read font name */
     settings->font_name =
         guac_user_parse_args_string(user, GUAC_TELNET_CLIENT_ARGS, argv,

src/protocols/telnet/settings.h

@@ -67,6 +67,11 @@
  */
 #define GUAC_TELNET_DEFAULT_PASSWORD_REGEX "[Pp]assword:"
 
+/**
+ * The default maximum scrollback size in rows.
+ */
+#define GUAC_TELNET_DEFAULT_MAX_SCROLLBACK 1000
+
 /**
  * Settings for the telnet connection. The values for this structure are parsed
  * from the arguments given during the Guacamole protocol handshake using the
@@ -117,6 +122,11 @@ typedef struct guac_telnet_settings {
      */
     bool read_only;
 
+    /**
+     * The maximum size of the scrollback buffer in rows.
+     */
+    int max_scrollback;
+
     /**
      * The name of the font to use for display rendering.
      */

src/protocols/telnet/telnet.c

@@ -479,7 +479,7 @@ 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->max_scrollback, settings->font_name, settings->font_size,
             settings->resolution, settings->width, settings->height,
             settings->color_scheme, settings->backspace);
 

src/terminal/terminal.c

@@ -149,6 +149,46 @@ static void __guac_terminal_force_break(guac_terminal* terminal, int row, int ed
 
 }
 
+/**
+ * Returns the number of rows available within the terminal buffer, taking
+ * changes to the desired scrollback size into account. Regardless of the
+ * true buffer length, only the number of rows that should be made available
+ * will be returned.
+ *
+ * @param term
+ *     The terminal whose effective buffer length should be retrieved.
+ *
+ * @return
+ *     The number of rows effectively available within the terminal buffer,
+ *     taking changes to the desired scrollback size into account.
+ */
+static int guac_terminal_effective_buffer_length(guac_terminal* term) {
+
+    int scrollback = term->requested_scrollback;
+
+    /* Limit available scrollback to defined maximum */
+    if (scrollback > term->max_scrollback)
+        scrollback = term->max_scrollback;
+
+    /* There must always be at least enough scrollback to cover the visible
+     * terminal display */
+    else if (scrollback < term->term_height)
+        scrollback = term->term_height;
+
+    /* If the buffer contains more rows than requested, pretend it only
+     * contains the requested number of rows */
+    int effective_length = term->buffer->length;
+    if (effective_length > scrollback)
+        effective_length = scrollback;
+
+    return effective_length;
+
+}
+
+int guac_terminal_available_scroll(guac_terminal* term) {
+    return guac_terminal_effective_buffer_length(term) - term->term_height;
+}
+
 void guac_terminal_reset(guac_terminal* term) {
 
     int row;
@@ -171,7 +211,7 @@ void guac_terminal_reset(guac_terminal* term) {
     term->scroll_offset = 0;
 
     /* Reset scrollbar bounds */
-    guac_terminal_scrollbar_set_bounds(term->scrollbar, term->term_height - term->buffer->length, 0);
+    guac_terminal_scrollbar_set_bounds(term->scrollbar, 0, 0);
     guac_terminal_scrollbar_set_value(term->scrollbar, -term->scroll_offset);
 
     /* Reset flags */
@@ -507,7 +547,7 @@ static void guac_terminal_parse_color_scheme(guac_client* client,
 }
 
 guac_terminal* guac_terminal_create(guac_client* client,
-        guac_common_clipboard* clipboard,
+        guac_common_clipboard* clipboard, int max_scrollback,
         const char* font_name, int font_size, int dpi,
         int width, int height, const char* color_scheme,
         const int backspace) {
@@ -565,8 +605,19 @@ guac_terminal* guac_terminal_create(guac_client* client,
     pthread_cond_init(&(term->modified_cond), NULL);
     pthread_mutex_init(&(term->modified_lock), NULL);
 
+    /* Maximum and requested scrollback are initially the same */
+    term->max_scrollback = max_scrollback;
+    term->requested_scrollback = max_scrollback;
+
+    /* Allocate enough space for maximum scrollback, bumping up internal
+     * storage as necessary to allow screen to be resized to maximum height */
+    int initial_scrollback = max_scrollback;
+    if (initial_scrollback < GUAC_TERMINAL_MAX_ROWS)
+        initial_scrollback = GUAC_TERMINAL_MAX_ROWS;
+
     /* Init buffer */
-    term->buffer = guac_terminal_buffer_alloc(1000, &default_char);
+    term->buffer = guac_terminal_buffer_alloc(initial_scrollback,
+            &default_char);
 
     /* Init display */
     term->display = guac_terminal_display_alloc(client,
@@ -590,13 +641,29 @@ guac_terminal* guac_terminal_create(guac_client* client,
     term->default_char = default_char;
     term->clipboard = clipboard;
 
+    /* Calculate character size */
+    int rows    = height / term->display->char_height;
+    int columns = available_width / term->display->char_width;
+
+    /* Keep height within predefined maximum */
+    if (rows > GUAC_TERMINAL_MAX_ROWS) {
+        rows = GUAC_TERMINAL_MAX_ROWS;
+        height = rows * term->display->char_height;
+    }
+
+    /* Keep width within predefined maximum */
+    if (columns > GUAC_TERMINAL_MAX_COLUMNS) {
+        columns = GUAC_TERMINAL_MAX_COLUMNS;
+        available_width = columns * term->display->char_width;
+        width = available_width + GUAC_TERMINAL_SCROLLBAR_WIDTH;
+    }
+
     /* Set pixel size */
     term->width = width;
     term->height = height;
 
-    /* Calculate character size */
+    term->term_width  = columns;
-    term->term_width   = available_width / term->display->char_width;
+    term->term_height = rows;
-    term->term_height  = height / term->display->char_height;
 
     /* Open STDIN pipe */
     if (pipe(term->stdin_pipe_fd)) {
@@ -1015,7 +1082,8 @@ int guac_terminal_scroll_up(guac_terminal* term,
             term->buffer->length = term->buffer->available;
 
         /* Reset scrollbar bounds */
-        guac_terminal_scrollbar_set_bounds(term->scrollbar, term->term_height - term->buffer->length, 0);
+        guac_terminal_scrollbar_set_bounds(term->scrollbar,
+                -guac_terminal_available_scroll(term), 0);
 
         /* Update cursor location if within region */
         if (term->visible_cursor_row >= start_row &&
@@ -1225,8 +1293,9 @@ void guac_terminal_scroll_display_up(guac_terminal* terminal,
     int row, column;
 
     /* Limit scroll amount by size of scrollback buffer */
-    if (terminal->scroll_offset + scroll_amount > terminal->buffer->length - terminal->term_height)
+    int available_scroll = guac_terminal_available_scroll(terminal);
-        scroll_amount = terminal->buffer->length - terminal->scroll_offset - terminal->term_height;
+    if (terminal->scroll_offset + scroll_amount > available_scroll)
+        scroll_amount = available_scroll - terminal->scroll_offset;
 
     /* If not scrolling at all, don't bother trying */
     if (scroll_amount <= 0)
@@ -1388,7 +1457,7 @@ static void __guac_terminal_resize(guac_terminal* term, int width, int height) {
         int shift_amount;
 
         /* Get number of rows actually occupying terminal space */
-        int used_height = term->buffer->length;
+        int used_height = guac_terminal_effective_buffer_length(term);
         if (used_height > term->term_height)
             used_height = term->term_height;
 
@@ -1424,16 +1493,15 @@ static void __guac_terminal_resize(guac_terminal* term, int width, int height) {
     if (height > term->term_height) {
 
         /* If undisplayed rows exist in the buffer, shift them into view */
-        if (term->term_height < term->buffer->length) {
+        int available_scroll = guac_terminal_available_scroll(term);
+        if (available_scroll > 0) {
 
             /* If the new terminal bottom reveals N rows, shift down N rows */
             int shift_amount = height - term->term_height;
 
             /* The maximum amount we can shift is the number of undisplayed rows */
-            int max_shift = term->buffer->length - term->term_height;
+            if (shift_amount > available_scroll)
-
+                shift_amount = available_scroll;
-            if (shift_amount > max_shift)
-                shift_amount = max_shift;
 
             /* Update buffer top and cursor row based on shift */
             term->buffer->top -= shift_amount;
@@ -1508,6 +1576,19 @@ int guac_terminal_resize(guac_terminal* terminal, int width, int height) {
     int rows    = height / display->char_height;
     int columns = available_width / display->char_width;
 
+    /* Keep height within predefined maximum */
+    if (rows > GUAC_TERMINAL_MAX_ROWS) {
+        rows = GUAC_TERMINAL_MAX_ROWS;
+        height = rows * display->char_height;
+    }
+
+    /* Keep width within predefined maximum */
+    if (columns > GUAC_TERMINAL_MAX_COLUMNS) {
+        columns = GUAC_TERMINAL_MAX_COLUMNS;
+        available_width = columns * display->char_width;
+        width = available_width + GUAC_TERMINAL_SCROLLBAR_WIDTH;
+    }
+
     /* Set pixel sizes */
     terminal->width = width;
     terminal->height = height;
@@ -1515,10 +1596,6 @@ int guac_terminal_resize(guac_terminal* terminal, int width, int height) {
     /* Resize default layer to given pixel dimensions */
     guac_terminal_repaint_default_layer(terminal, client->socket);
 
-    /* Notify scrollbar of resize */
-    guac_terminal_scrollbar_parent_resized(terminal->scrollbar, width, height, rows);
-    guac_terminal_scrollbar_set_bounds(terminal->scrollbar, rows - terminal->buffer->length, 0);
-
     /* Resize terminal if row/column dimensions have changed */
     if (columns != terminal->term_width || rows != terminal->term_height) {
 
@@ -1533,6 +1610,12 @@ int guac_terminal_resize(guac_terminal* terminal, int width, int height) {
 
     }
 
+    /* Notify scrollbar of resize */
+    guac_terminal_scrollbar_parent_resized(terminal->scrollbar, width, height, rows);
+    guac_terminal_scrollbar_set_bounds(terminal->scrollbar,
+            -guac_terminal_available_scroll(terminal), 0);
+
+
     /* Release terminal */
     guac_terminal_unlock(terminal);
 

src/terminal/terminal/terminal.h

@@ -37,6 +37,17 @@
 #include <guacamole/client.h>
 #include <guacamole/stream.h>
 
+/**
+ * The absolute maximum number of rows to allow within the display.
+ */
+#define GUAC_TERMINAL_MAX_ROWS 1024
+
+/**
+ * The absolute maximum number of columns to allow within the display. This
+ * implicitly limits the number of columns allowed within the buffer.
+ */
+#define GUAC_TERMINAL_MAX_COLUMNS 1024
+
 /**
  * The maximum duration of a single frame, in milliseconds.
  */
@@ -271,6 +282,26 @@ struct guac_terminal {
      */
     int scroll_offset;
 
+    /**
+     * The maximum number of rows to allow within the terminal buffer. Note
+     * that while this value is traditionally referred to as the scrollback
+     * size, it actually encompasses both the display and the off-screen
+     * region. The terminal will ensure enough buffer space is allocated for
+     * the on-screen rows, even if this exceeds the defined maximum, however
+     * additional rows for off-screen data will only be available if the
+     * display is smaller than this value.
+     */
+    int max_scrollback;
+
+    /**
+     * The number of rows that the user has requested be avalable within the
+     * terminal buffer. This value may be adjusted by the user while the
+     * terminal is running through console codes, and will adjust the number
+     * of rows available within the terminal buffer, subject to the maximum
+     * defined at terminal creation and stored within max_scrollback.
+     */
+    int requested_scrollback;
+
     /**
      * The width of the terminal, in pixels.
      */
@@ -507,6 +538,16 @@ struct guac_terminal {
  *     clipboard instructions. This clipboard will not be automatically
  *     freed when this terminal is freed.
  *
+ * @param max_scrollback
+ *     The maximum number of rows to allow within the scrollback buffer. The
+ *     user may still alter the size of the scrollback buffer using terminal
+ *     codes, however the size can never exceed the maximum size given here.
+ *     Note that this space is shared with the display, with the scrollable
+ *     area actually only containing the given number of rows less the number
+ *     of rows currently displayed, and sufficient buffer space will always be
+ *     allocated to represent the display area of the terminal regardless of
+ *     the value given here.
+ *
  * @param font_name
  *     The name of the font to use when rendering glyphs.
  *
@@ -539,7 +580,7 @@ struct guac_terminal {
  *     which renders all text to the given client.
  */
 guac_terminal* guac_terminal_create(guac_client* client,
-        guac_common_clipboard* clipboard,
+        guac_common_clipboard* clipboard, int max_scrollback,
         const char* font_name, int font_size, int dpi,
         int width, int height, const char* color_scheme,
         const int backspace);
@@ -1022,5 +1063,20 @@ void guac_terminal_pipe_stream_close(guac_terminal* term);
 int guac_terminal_create_typescript(guac_terminal* term, const char* path,
         const char* name, int create_path);
 
+/**
+ * Returns the number of rows within the buffer of the given terminal which are
+ * not currently displayed on screen. Adjustments to the desired scrollback
+ * size are taken into account, and rows which are within the buffer but
+ * unavailable due to being outside the desired scrollback range are ignored.
+ *
+ * @param term
+ *     The terminal whose off-screen row count should be determined.
+ *
+ * @return
+ *     The number of rows within the buffer which are not currently displayed
+ *     on screen.
+ */
+int guac_terminal_available_scroll(guac_terminal* term);
+
 #endif
 

src/terminal/terminal/terminal_handlers.h

@@ -138,6 +138,24 @@ int guac_terminal_open_pipe_stream(guac_terminal* term, unsigned char c);
  */
 int guac_terminal_close_pipe_stream(guac_terminal* term, unsigned char c);
 
+/**
+ * Parses the remainder of the OSC sequence specific to the Guacamole terminal
+ * emulator which requests that the scrollback buffer size be set to the given
+ * number of rows. The desired scrollback buffer size will immediately be set,
+ * however the manner in which that size is applied (or whether the size is
+ * applied at all) depends on (1) whether the requested size exceeds the
+ * maximum size set when the terminal emulator was created and (2) whether the
+ * size does not reduce the scrollback below the number of rows required for
+ * the current display.
+ *
+ * @param term
+ *     The terminal that received the given character of data.
+ *
+ * @param c
+ *     The character that was received by the given terminal.
+ */
+int guac_terminal_set_scrollback(guac_terminal* term, unsigned char c);
+
 /**
  * Parses the remainder of an OSC sequence setting the window title. The
  * window title is everything after the window title sequence begins, up to

src/terminal/terminal_handlers.c

@@ -1208,6 +1208,39 @@ int guac_terminal_close_pipe_stream(guac_terminal* term, unsigned char c) {
 
 }
 
+int guac_terminal_set_scrollback(guac_terminal* term, unsigned char c) {
+
+    static char param[16];
+    static int length = 0;
+
+    /* Open pipe on ECMA-48 ST (String Terminator) */
+    if (c == 0x9C || c == 0x5C || c == 0x07) {
+
+        /* End parameter string */
+        param[length++] = '\0';
+        length = 0;
+
+        /* Assign scrollback size */
+        term->requested_scrollback = atoi(param);
+
+        /* Update scrollbar bounds */
+        guac_terminal_scrollbar_set_bounds(term->scrollbar,
+                -guac_terminal_available_scroll(term), 0);
+
+        /* Return to echo mode */
+        term->char_handler = guac_terminal_echo;
+
+    }
+
+    /* Otherwise, store character within parameter */
+    else if (length < sizeof(param) - 1)
+        param[length++] = c;
+
+    return 0;
+
+}
+
+
 int guac_terminal_window_title(guac_terminal* term, unsigned char c) {
 
     static int position = 0;
@@ -1346,6 +1379,10 @@ int guac_terminal_osc(guac_terminal* term, unsigned char c) {
         else if (operation == 482203)
             term->char_handler = guac_terminal_close_pipe_stream;
 
+        /* Set scrollback size OSC */
+        else if (operation == 482204)
+            term->char_handler = guac_terminal_set_scrollback;
+
         /* Set window title OSC */
         else if (operation == 0 || operation == 2)
             term->char_handler = guac_terminal_window_title;