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Cygwin: pty: Implement new pseudo console support.

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- 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.
This commit is contained in:
Takashi Yano
2020-08-19 20:25:21 +09:00
committed by Corinna Vinschen
parent b9261fa1d9
commit bb42852062
12 changed files with 340 additions and 1720 deletions
Download Patch File Download Diff File Expand all files Collapse all files

105
winsup/cygwin/spawn.cc
View File

@@ -177,7 +177,7 @@ find_exec (const char *name, path_conv& buf, const char *search,
/* Utility for child_info_spawn::worker. */
static HANDLE
handle (int fd, bool writing, bool iscygwin)
handle (int fd, bool writing)
{
HANDLE h;
cygheap_fdget cfd (fd);
@@ -188,17 +188,30 @@ handle (int fd, bool writing, bool iscygwin)
h = INVALID_HANDLE_VALUE;
else if (!writing)
h = cfd->get_handle ();
else if (cfd->get_major () == DEV_PTYS_MAJOR && iscygwin)
{
fhandler_pty_slave *ptys = (fhandler_pty_slave *)(fhandler_base *) cfd;
h = ptys->get_output_handle_cyg ();
}
else
h = cfd->get_output_handle ();
return h;
}
static bool
is_console_app (WCHAR *filename)
{
HANDLE h;
const int id_offset = 92;
h = CreateFileW (filename, GENERIC_READ, FILE_SHARE_READ,
NULL, OPEN_EXISTING, 0, NULL);
char buf[1024];
DWORD n;
ReadFile (h, buf, sizeof (buf), &n, 0);
CloseHandle (h);
char *p = (char *) memmem (buf, n, "PE\0\0", 4);
if (p && p + id_offset <= buf + n)
return p[id_offset] == '\003'; /* 02: GUI, 03: console */
else
return false;
}
int
iscmd (const char *argv0, const char *what)
{
@@ -266,8 +279,6 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
{
bool rc;
int res = -1;
DWORD pid_restore = 0;
bool attach_to_console = false;
pid_t ctty_pgid = 0;
/* Search for CTTY and retrieve its PGID */
@@ -587,9 +598,7 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
PROCESS_QUERY_LIMITED_INFORMATION))
sa = &sec_none_nih;
/* Attach to pseudo console if pty salve is used */
pid_restore = fhandler_console::get_console_process_id
(GetCurrentProcessId (), false);
fhandler_pty_slave *ptys_primary = NULL;
for (int i = 0; i < 3; i ++)
{
const int chk_order[] = {1, 0, 2};
@@ -598,29 +607,11 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
if (fh && fh->get_major () == DEV_PTYS_MAJOR)
{
fhandler_pty_slave *ptys = (fhandler_pty_slave *) fh;
if (ptys->get_pseudo_console ())
{
DWORD helper_process_id = ptys->get_helper_process_id ();
debug_printf ("found a PTY slave %d: helper_PID=%d",
fh->get_minor (), helper_process_id);
if (fhandler_console::get_console_process_id
(helper_process_id, true))
/* Already attached */
attach_to_console = true;
else if (!attach_to_console)
{
FreeConsole ();
if (AttachConsole (helper_process_id))
attach_to_console = true;
}
ptys->fixup_after_attach (!iscygwin (), fd);
if (mode == _P_OVERLAY)
ptys->set_freeconsole_on_close (iscygwin ());
}
if (ptys_primary == NULL)
ptys_primary = ptys;
}
else if (fh && fh->get_major () == DEV_CONS_MAJOR)
{
attach_to_console = true;
fhandler_console *cons = (fhandler_console *) fh;
if (wincap.has_con_24bit_colors () && !iscygwin ())
if (fd == 1 || fd == 2)
@@ -642,17 +633,28 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
/* Set up needed handles for stdio */
si.dwFlags = STARTF_USESTDHANDLES;
si.hStdInput = handle ((in__stdin < 0 ? 0 : in__stdin), false,
iscygwin ());
si.hStdOutput = handle ((in__stdout < 0 ? 1 : in__stdout), true,
iscygwin ());
si.hStdError = handle (2, true, iscygwin ());
si.hStdInput = handle ((in__stdin < 0 ? 0 : in__stdin), false);
si.hStdOutput = handle ((in__stdout < 0 ? 1 : in__stdout), true);
si.hStdError = handle (2, true);
si.cb = sizeof (si);
if (!iscygwin ())
init_console_handler (myself->ctty > 0);
bool enable_pcon = false;
STARTUPINFOEXW si_pcon;
ZeroMemory (&si_pcon, sizeof (si_pcon));
STARTUPINFOW *si_tmp = &si;
if (!iscygwin () && ptys_primary && is_console_app (runpath))
if (ptys_primary->setup_pseudoconsole (&si_pcon,
mode != _P_OVERLAY && mode != _P_WAIT))
{
c_flags |= EXTENDED_STARTUPINFO_PRESENT;
si_tmp = &si_pcon.StartupInfo;
enable_pcon = true;
}
loop:
/* When ruid != euid we create the new process under the current original
account and impersonate in child, this way maintaining the different
@@ -681,7 +683,7 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
c_flags,
envblock, /* environment */
NULL,
&si,
si_tmp,
&pi);
}
else
@@ -735,7 +737,7 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
c_flags,
envblock, /* environment */
NULL,
&si,
si_tmp,
&pi);
if (hwst)
{
@@ -748,6 +750,11 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
CloseDesktop (hdsk);
}
}
if (enable_pcon)
{
DeleteProcThreadAttributeList (si_pcon.lpAttributeList);
HeapFree (GetProcessHeap (), 0, si_pcon.lpAttributeList);
}
if (mode != _P_OVERLAY)
SetHandleInformation (my_wr_proc_pipe, HANDLE_FLAG_INHERIT,
@@ -920,6 +927,11 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
}
if (sem)
__posix_spawn_sem_release (sem, 0);
if (enable_pcon)
{
WaitForSingleObject (pi.hProcess, INFINITE);
ptys_primary->close_pseudoconsole ();
}
myself.exit (EXITCODE_NOSET);
break;
case _P_WAIT:
@@ -927,6 +939,8 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
system_call.arm ();
if (waitpid (cygpid, &res, 0) != cygpid)
res = -1;
if (enable_pcon)
ptys_primary->close_pseudoconsole ();
break;
case _P_DETACH:
res = 0; /* Lost all memory of this child. */
@@ -953,21 +967,6 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
if (envblock)
free (envblock);
if (attach_to_console && pid_restore)
{
FreeConsole ();
AttachConsole (pid_restore);
cygheap_fdenum cfd (false);
int fd;
while ((fd = cfd.next ()) >= 0)
if (cfd->get_major () == DEV_PTYS_MAJOR)
{
fhandler_pty_slave *ptys =
(fhandler_pty_slave *) (fhandler_base *) cfd;
ptys->fixup_after_attach (false, fd);
}
}
return (int) res;
}