[PATCH v2] Cygwin: pty: Use atexit() instead of hooking exit() for GDB.
Takashi Yano
takashi.yano@nifty.ne.jp
Tue Apr 6 00:40:13 GMT 2021
- This patch utilizes atexit() instead of hooking exit() to clean
up pseudo console stuff when debugging non-cygwin app using GDB.
---
winsup/cygwin/fhandler.h | 2 +-
winsup/cygwin/fhandler_tty.cc | 100 +++++++++++++++++++++++-----------
winsup/cygwin/tty.cc | 2 +
3 files changed, 70 insertions(+), 34 deletions(-)
diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index 15fbd09b0..9df617b99 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -2374,7 +2374,7 @@ class fhandler_pty_slave: public fhandler_pty_common
return fh;
}
bool setup_pseudoconsole (bool nopcon);
- static void close_pseudoconsole (tty *ttyp);
+ static void close_pseudoconsole (tty *ttyp, DWORD force_switch_to = 0);
bool term_has_pcon_cap (const WCHAR *env);
void set_switch_to_pcon (void);
void reset_switch_to_pcon (void);
diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index 12247dd99..470fe8d42 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -147,11 +147,47 @@ set_switch_to_pcon (HANDLE *in, HANDLE *out, HANDLE *err, bool iscygwin)
*err = replace_err->get_output_handle_nat ();
}
+static bool atexit_func_registered = false;
+static bool debug_process = false;
+
+static void
+atexit_func (void)
+{
+ if (isHybrid)
+ {
+ cygheap_fdenum cfd (false);
+ while (cfd.next () >= 0)
+ if (cfd->get_device () == (dev_t) myself->ctty)
+ {
+ DWORD force_switch_to = 0;
+ if (WaitForSingleObject (h_gdb_process, 0) == WAIT_TIMEOUT
+ && !debug_process)
+ force_switch_to = GetProcessId (h_gdb_process);
+ fhandler_base *fh = cfd;
+ fhandler_pty_slave *ptys = (fhandler_pty_slave *) fh;
+ tty *ttyp = ptys->get_ttyp ();
+ HANDLE from = ptys->get_handle_nat ();
+ HANDLE input_available_event = ptys->get_input_available_event ();
+ if (ttyp->getpgid () == myself->pgid
+ && GetStdHandle (STD_INPUT_HANDLE) == ptys->get_handle ()
+ && ttyp->pcon_input_state_eq (tty::to_nat) && !force_switch_to)
+ {
+ WaitForSingleObject (ptys->input_mutex, INFINITE);
+ fhandler_pty_slave::transfer_input (tty::to_cyg, from, ttyp,
+ input_available_event);
+ ReleaseMutex (ptys->input_mutex);
+ }
+ ptys->close_pseudoconsole (ttyp, force_switch_to);
+ break;
+ }
+ CloseHandle (h_gdb_process);
+ }
+}
+
#define DEF_HOOK(name) static __typeof__ (name) *name##_Orig
/* CreateProcess() is hooked for GDB etc. */
DEF_HOOK (CreateProcessA);
DEF_HOOK (CreateProcessW);
-DEF_HOOK (exit);
static BOOL WINAPI
CreateProcessA_Hooked
@@ -207,8 +243,15 @@ CreateProcessA_Hooked
DuplicateHandle (GetCurrentProcess (), h_gdb_process,
GetCurrentProcess (), &h_gdb_process,
0, 0, DUPLICATE_SAME_ACCESS);
+ debug_process = !!(f & (DEBUG_PROCESS | DEBUG_ONLY_THIS_PROCESS));
+ if (!atexit_func_registered && !path.iscygexec ())
+ {
+ atexit (atexit_func);
+ atexit_func_registered = true;
+ }
return ret;
}
+
static BOOL WINAPI
CreateProcessW_Hooked
(LPCWSTR n, LPWSTR c, LPSECURITY_ATTRIBUTES pa, LPSECURITY_ATTRIBUTES ta,
@@ -263,36 +306,13 @@ CreateProcessW_Hooked
DuplicateHandle (GetCurrentProcess (), h_gdb_process,
GetCurrentProcess (), &h_gdb_process,
0, 0, DUPLICATE_SAME_ACCESS);
- return ret;
-}
-
-void
-exit_Hooked (int e)
-{
- if (isHybrid)
+ debug_process = !!(f & (DEBUG_PROCESS | DEBUG_ONLY_THIS_PROCESS));
+ if (!atexit_func_registered && !path.iscygexec ())
{
- cygheap_fdenum cfd (false);
- while (cfd.next () >= 0)
- if (cfd->get_device () == (dev_t) myself->ctty)
- {
- fhandler_base *fh = cfd;
- fhandler_pty_slave *ptys = (fhandler_pty_slave *) fh;
- tty *ttyp = ptys->get_ttyp ();
- HANDLE from = ptys->get_handle_nat ();
- HANDLE input_available_event = ptys->get_input_available_event ();
- if (ttyp->getpgid () == myself->pgid
- && GetStdHandle (STD_INPUT_HANDLE) == ptys->get_handle ()
- && ttyp->pcon_input_state_eq (tty::to_nat))
- {
- WaitForSingleObject (ptys->input_mutex, INFINITE);
- fhandler_pty_slave::transfer_input (tty::to_cyg, from, ttyp,
- input_available_event);
- ReleaseMutex (ptys->input_mutex);
- }
- break;
- }
+ atexit (atexit_func);
+ atexit_func_registered = true;
}
- exit_Orig (e);
+ return ret;
}
static void
@@ -1131,6 +1151,15 @@ fhandler_pty_slave::reset_switch_to_pcon (void)
if (isHybrid)
return;
WaitForSingleObject (pcon_mutex, INFINITE);
+ HANDLE h;
+ if (get_ttyp ()->pcon_pid > MAX_PID &&
+ (h = OpenProcess (SYNCHRONIZE, FALSE, get_ttyp ()->pcon_pid - MAX_PID)))
+ {
+ /* There is a process which is grabbing pseudo console. */
+ CloseHandle (h);
+ ReleaseMutex (pcon_mutex);
+ return;
+ }
if (get_ttyp ()->pcon_pid && get_ttyp ()->pcon_pid != myself->pid
&& !!pinfo (get_ttyp ()->pcon_pid))
{
@@ -1138,6 +1167,7 @@ fhandler_pty_slave::reset_switch_to_pcon (void)
ReleaseMutex (pcon_mutex);
return;
}
+ get_ttyp ()->pcon_input_state = tty::to_cyg;
get_ttyp ()->pcon_pid = 0;
get_ttyp ()->switch_to_pcon_in = false;
get_ttyp ()->pcon_activated = false;
@@ -2337,8 +2367,6 @@ fhandler_pty_slave::fixup_after_exec ()
/* CreateProcess() is hooked for GDB etc. */
DO_HOOK (NULL, CreateProcessA);
DO_HOOK (NULL, CreateProcessW);
- if (CreateProcessA_Orig || CreateProcessW_Orig)
- DO_HOOK (NULL, exit);
}
/* This thread function handles the master control pipe. It waits for a
@@ -3344,11 +3372,17 @@ fallback:
/* The function close_pseudoconsole() should be static so that it can
be called even after the fhandler_pty_slave instance is deleted. */
void
-fhandler_pty_slave::close_pseudoconsole (tty *ttyp)
+fhandler_pty_slave::close_pseudoconsole (tty *ttyp, DWORD force_switch_to)
{
DWORD switch_to_stub = 0, switch_to = 0;
DWORD new_pcon_pid = 0;
- if (ttyp->pcon_pid == myself->pid)
+ if (force_switch_to)
+ {
+ switch_to_stub = force_switch_to;
+ new_pcon_pid = force_switch_to + MAX_PID;
+ ttyp->setpgid (new_pcon_pid);
+ }
+ else if (ttyp->pcon_pid == myself->pid)
{
/* Search another process which attaches to the pseudo console */
DWORD current_pid = myself->exec_dwProcessId ?: myself->dwProcessId;
diff --git a/winsup/cygwin/tty.cc b/winsup/cygwin/tty.cc
index 5ed88d0e4..96acde387 100644
--- a/winsup/cygwin/tty.cc
+++ b/winsup/cygwin/tty.cc
@@ -402,5 +402,7 @@ tty::pcon_fg (pid_t pgid)
if (p->ctty == ntty && p->pgid == pgid && p->exec_dwProcessId)
return true;
}
+ if (pgid > MAX_PID)
+ return true;
return false;
}
--
2.31.1
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