newlib/winsup/cygwin/tty.h
Takashi Yano bb42852062 Cygwin: pty: Implement new pseudo console support.
- In this implementation, pseudo console is created for each native
  console app. Advantages and disadvantages of this implementation
  over the previous implementation are as follows.

  Advantages:
  1) No performance degradation in pty output for cygwin process.
      https://cygwin.com/pipermail/cygwin/2020-February/243858.html
  2) Free from the problem caused by difference of behaviour of control
     sequences between real terminal and pseudo console.
      https://cygwin.com/pipermail/cygwin/2019-December/243281.html
      https://cygwin.com/pipermail/cygwin/2020-February/243855.html
  3) Free from the problem in cgdb and emacs gud.
      https://cygwin.com/pipermail/cygwin/2020-January/243601.html
      https://cygwin.com/pipermail/cygwin/2020-March/244146.html
  4) Redrawing screen on executing native console apps is not necessary.
  5) cygwin-console-helper is not necessary for the pseudo console
     support.
  6) The codes for pseudo console support are much simpler than that
     of the previous one.

  Disadvantages:
  1) The cygwin program which calls console API directly does not work.
  2) The apps which use console API cannot be debugged with gdb. This
     is because pseudo console is not activated since gdb uses
     CreateProcess() rather than exec(). Even with this limitation,
     attaching gdb to native apps, in which pseudo console is already
     activated, works.
  3) Typeahead key inputs are discarded while native console app is
     executed. Simirally, typeahead key inputs while cygwin app is
     executed are not inherited to native console app.
  4) Code page cannot be changed by chcp.com. Acctually, chcp works
     itself and changes code page of its own pseudo console.  However,
     since pseudo console is recreated for another process, it cannot
     inherit the code page.
  5) system_printf() does not work after stderr is closed. (Same with
     cygwin 3.0.7)
  6) Startup time of native console apps is about 3 times slower than
     previous implemenation.
  7) Pseudo console cannot be activated if it is already activated for
     another process on same pty.
2020-08-22 13:43:49 +02:00

171 lines
4.4 KiB
C++

/* tty.h: shared tty info for cygwin
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#ifndef _TTY_H
#define _TTY_H
/* tty tables */
#define INP_BUFFER_SIZE 256
#define OUT_BUFFER_SIZE 256
#define NTTYS 128
#define real_tty_attached(p) ((p)->ctty > 0 && !iscons_dev ((p)->ctty))
/* Input/Output/ioctl events */
#define INPUT_AVAILABLE_EVENT "cygtty.input.avail"
#define OUTPUT_MUTEX "cygtty.output.mutex"
#define INPUT_MUTEX "cygtty.input.mutex"
#define TTY_SLAVE_ALIVE "cygtty.slave_alive"
#include <sys/termios.h>
#ifndef MIN_CTRL_C_SLOP
#define MIN_CTRL_C_SLOP 50
#endif
typedef void *HPCON;
#include <devices.h>
class tty_min
{
pid_t sid; /* Session ID of tty */
struct status_flags
{
unsigned initialized : 1; /* Set if tty is initialized */
unsigned rstcons : 1; /* Set if console needs to be set to "non-cooked" */
} status;
public:
pid_t pgid;
bool output_stopped; /* FIXME: Maybe do this with a mutex someday? */
fh_devices ntty;
ULONGLONG last_ctrl_c; /* tick count of last ctrl-c */
bool is_console;
IMPLEMENT_STATUS_FLAG (bool, initialized)
IMPLEMENT_STATUS_FLAG (bool, rstcons)
struct termios ti;
struct winsize winsize;
/* ioctl requests buffer */
int cmd;
union
{
struct termios termios;
struct winsize winsize;
int value;
pid_t pid;
} arg;
/* XXX_retval variables holds master's completion codes. Error are stored as
* -ERRNO
*/
int ioctl_retval;
void setntty (_major_t t, _minor_t n) {ntty = (fh_devices) FHDEV (t, n);}
dev_t getntty () const {return ntty;}
_minor_t get_minor () const {return device::minor (ntty);}
pid_t getpgid () const {return pgid;}
void setpgid (int pid) {pgid = pid;}
int getsid () const {return sid;}
void setsid (pid_t tsid) {sid = tsid;}
void kill_pgrp (int);
int is_orphaned_process_group (int);
const __reg1 char *ttyname () __attribute (());
};
class fhandler_pty_master;
class tty: public tty_min
{
HANDLE __reg3 get_event (const char *fmt, PSECURITY_ATTRIBUTES sa,
BOOL manual_reset = FALSE);
public:
pid_t master_pid; /* PID of tty master process */
private:
HANDLE _from_master;
HANDLE _from_master_cyg;
HANDLE _to_master;
HANDLE _to_master_cyg;
HPCON h_pseudo_console;
bool pcon_start;
bool switch_to_pcon_in;
bool mask_switch_to_pcon_in;
pid_t pcon_pid;
UINT term_code_page;
DWORD pcon_last_time;
HANDLE h_pcon_write_pipe;
public:
HANDLE from_master () const { return _from_master; }
HANDLE from_master_cyg () const { return _from_master_cyg; }
HANDLE to_master () const { return _to_master; }
HANDLE to_master_cyg () const { return _to_master_cyg; }
void set_from_master (HANDLE h) { _from_master = h; }
void set_from_master_cyg (HANDLE h) { _from_master_cyg = h; }
void set_to_master (HANDLE h) { _to_master = h; }
void set_to_master_cyg (HANDLE h) { _to_master_cyg = h; }
int read_retval;
bool was_opened; /* True if opened at least once. */
int column; /* Current Column */
void init ();
HANDLE open_inuse (ACCESS_MASK access);
HANDLE create_inuse (PSECURITY_ATTRIBUTES);
bool slave_alive ();
HANDLE open_mutex (const char *mutex, ACCESS_MASK access);
inline HANDLE open_output_mutex (ACCESS_MASK access)
{ return open_mutex (OUTPUT_MUTEX, access); }
inline HANDLE open_input_mutex (ACCESS_MASK access)
{ return open_mutex (INPUT_MUTEX, access); }
bool exists ();
bool not_allocated (HANDLE&, HANDLE&);
void set_master_ctl_closed () {master_pid = -1;}
static void __stdcall create_master (int);
static void __stdcall init_session ();
void wait_pcon_fwd (void);
friend class fhandler_pty_common;
friend class fhandler_pty_master;
friend class fhandler_pty_slave;
};
class tty_list
{
tty ttys[NTTYS];
static HANDLE mutex;
public:
tty * operator [](int n) {return ttys + device::minor (n);}
int allocate (HANDLE& r, HANDLE& w); /* allocate a pty */
int connect (int);
void init ();
tty_min *get_cttyp ();
int __reg2 attach (int n);
static void __stdcall init_session ();
friend class lock_ttys;
};
class lock_ttys
{
bool release_me;
public:
lock_ttys (DWORD = INFINITE);
static void release ();
void dont_release () {release_me = false;}
~lock_ttys ()
{
if (release_me)
release ();
}
};
extern "C" int ttyslot (void);
#endif /*_TTY_H*/