Issue #157: Use the current TTY's settings by default.

When opening a PTY on the server, try to use the current TTY's settings
(i.e. based on STDIN). If that fails or STDIN isn't a TTY, use default
modes that avoid any character translation.

Don't rely on stdin to be a TTY (breaks CI). Instead, open a PTY and
temporarily use that as "fake" stdin.

Signed-off-by: Daniel Evers (daniel.evers@utimaco.com)
Reviewed-by: Jakub Jelen <jjelen@redhat.com>

include/libssh/priv.h

@@ -47,6 +47,10 @@
 # endif
 #endif /* !defined(HAVE_STRTOULL) */
 
+#ifdef HAVE_TERMIOS_H
+#include <termios.h>
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -452,6 +456,10 @@ bool is_ssh_initialized(void);
 #define SSH_ERRNO_MSG_MAX   1024
 char *ssh_strerror(int err_num, char *buf, size_t buflen);
 
+/** 55 defined options (5 bytes each) + terminator */
+#define SSH_TTY_MODES_MAX_BUFSIZE   (55 * 5 + 1)
+int encode_current_tty_opts(unsigned char *buf, size_t buflen);
+
 #ifdef __cplusplus
 }
 #endif