A color scheme string should always be provided, even if blank.
Disallowing NULL allows assumptions to be made which simplifies the
logic surrounding persisting provided configuration values.
Older versions of GCC (prior to 5.1) emits an "incompatible pointer
type" warning when passing `foo(*)[]` as `const foo(*)[]`. This was
changed in GCC 5.1, and this patch adds explicit casts to remove the
warning under older GCC.
An APC escape sequence contains an arbitrary string command between
(ESC _) and (ESC \) sequences. While we don't support any APC commands, we
should ignore any commands that we do encounter.
Add support for configuring individual colors in the color-scheme
parameter, by parsing the parameter content into name-value pairs.
Backward compatibility is preserved by translating previously supported
values into corresponding new values.
Add support for configuring a default palette for a terminal display.
When the default palette is specified during display creation, that
palette is used instead of GUAC_TERMINAL_INITIAL_PALETTE when resetting
the display palette.
Root Cause:
See the core dump and Valgrind report posted on Jira. guacd was reading a ssh terminal which had been freed. When a ssh connection is terminated, guac_ssh_client_free_handler() will be called from guacd_exec_proc() -> guac_client_free() with pointer client->free_handler. In guac_ssh_client_free_handler(), when ssh_client->term is freed, ssh_client->client_thread may still be using the ssh_client->term. It causes the crash reported in this bug.
The stack trace exposing the problem can be found by running guacd under Valgrind with a ssh test script. The test script repeats doing ssh login and logout for 5000 times.
Solution:
In guac_ssh_client_free_handler(), before calling guac_terminal_free(ssh_client->term), close the stdin pipe of the terminal to stop reading the pipe with guac_terminal_read_stdin() in ssh_input_thread(). So that ssh_input_thread() can be terminated in this case. Call pthread_join() to wait for ssh_client_thread() terminating before freeing the terminal.
Add a new function guac_terminal_stop() to close the pipe and set the fds to invalid (-1). Call it in guac_ssh_client_free_handler() and guac_terminal_free().
Checking the client running state in ssh_input_thread() and ssh_client_thread() to make sure they can be terminated when the client is stopped in guacd_exec_proc() by another thread.
Test:
- Confirmed ssh connection works normally.
- Observed the child process of guacd exits when ssh connection is terminated.
- Reran the ssh test script. Observed no crash.
