Merge branch '117_sigwinch'

* 117_sigwinch:
  Ticket #117: refactoring of SIGWINCH hangling.

lib/global.c

@@ -104,8 +104,7 @@ mc_global_t mc_global = {
         .disable_colors = FALSE,
         .ugly_line_drawing = FALSE,
         .old_mouse = FALSE,
-        .alternate_plus_minus = FALSE,
-        .winch_flag = 0
+        .alternate_plus_minus = FALSE
     },
 
     .vfs =

lib/global.h

@@ -275,9 +275,6 @@ typedef struct
         /* If true, use + and \ keys normally and select/unselect do if M-+ / M-\.
            and M-- and keypad + / - */
         gboolean alternate_plus_minus;
-
-        /* Set if the window has changed it's size */
-        SIG_ATOMIC_VOLATILE_T winch_flag;
     } tty;
 
     struct

lib/tty/Makefile.am

@@ -16,7 +16,8 @@ TTY_SRC = \
 	color.c color.h \
 	key.c key.h keyxdef.c \
 	mouse.c mouse.h \
-	tty.c tty.h tty-internal.h \
+	tty-internal.c tty-internal.h \
+	tty.c tty.h \
 	win.c win.h
 
 if HAVE_TEXTMODE_X11_SUPPORT

lib/tty/key.c

@@ -2028,7 +2028,7 @@ tty_get_event (struct Gpm_Event *event, gboolean redo_event, gboolean block)
             }
         }
 
-        if (!block || mc_global.tty.winch_flag != 0)
+        if (!block || tty_got_winch ())
         {
             time_addr = &time_out;
             time_out.tv_sec = 0;
@@ -2048,7 +2048,7 @@ tty_get_event (struct Gpm_Event *event, gboolean redo_event, gboolean block)
         {
             if (redo_event)
                 return EV_MOUSE;
-            if (!block || mc_global.tty.winch_flag != 0)
+            if (!block || tty_got_winch ())
                 return EV_NONE;
             vfs_timeout_handler ();
         }

lib/tty/tty-internal.c

@@ -0,0 +1,104 @@
+/*
+   Internal stuff of the terminal controlling library.
+
+   Copyright (C) 2019
+   Free Software Foundation, Inc.
+
+   Written by:
+   Andrew Borodin <aborodin@vmail.ru>, 2019.
+
+   This file is part of the Midnight Commander.
+
+   The Midnight Commander is free software: you can redistribute it
+   and/or modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation, either version 3 of the License,
+   or (at your option) any later version.
+
+   The Midnight Commander is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** \file
+ *  \brief Source: internal stuff of the terminal controlling library.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "lib/global.h"
+
+#include "tty-internal.h"
+
+/*** global variables ****************************************************************************/
+
+/* pipe to handle SIGWINCH */
+int sigwinch_pipe[2];
+
+/*** file scope macro definitions ****************************************************************/
+
+/*** global variables ****************************************************************************/
+
+/*** file scope type declarations ****************************************************************/
+
+/*** file scope variables ************************************************************************/
+
+/* --------------------------------------------------------------------------------------------- */
+/*** file scope functions ************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+/* --------------------------------------------------------------------------------------------- */
+/*** public functions ****************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+void
+tty_create_winch_pipe (void)
+{
+    int fd_flags;
+
+    if (pipe (sigwinch_pipe) == -1)
+    {
+        perror (_("Cannot create pipe for SIGWINCH"));
+        exit (EXIT_FAILURE);
+    }
+
+    /* If we read from an empty pipe, then read(2) will block until data is available.
+     * If we write to a full pipe, then write(2) blocks until sufficient data has been read
+     * from the pipe to allow the write to complete..
+     * Therefore, use nonblocking I/O.
+     */
+
+    fd_flags = fcntl (sigwinch_pipe[0], F_GETFL, NULL);
+    if (fd_flags != -1)
+    {
+        fd_flags |= O_NONBLOCK | O_CLOEXEC;
+        fd_flags = fcntl (sigwinch_pipe[0], F_SETFL, fd_flags);
+    }
+    if (fd_flags == -1)
+    {
+        perror (_("Cannot configure write end of SIGWINCH pipe"));
+        exit (EXIT_FAILURE);
+    }
+
+    fd_flags = fcntl (sigwinch_pipe[1], F_GETFL, NULL);
+    if (fd_flags != -1)
+    {
+        fd_flags |= O_NONBLOCK | O_CLOEXEC;
+        fd_flags = fcntl (sigwinch_pipe[1], F_SETFL, fd_flags);
+    }
+    if (fd_flags == -1)
+    {
+        perror (_("Cannot configure read end of SIGWINCH pipe"));
+        exit (EXIT_FAILURE);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */

lib/tty/tty-internal.h

@@ -30,11 +30,17 @@ extern gboolean mouse_enabled;
 extern char *smcup;
 extern char *rmcup;
 
+/* pipe to handle SIGWINCH */
+extern int sigwinch_pipe[2];
+
 /*** declarations of public functions ************************************************************/
 
+void tty_create_winch_pipe (void);
+
 char *mc_tty_normalize_from_utf8 (const char *);
 void tty_init_xterm_support (gboolean is_xterm);
 int tty_lowlevel_getch (void);
 
 /*** inline functions ****************************************************************************/
+
 #endif /* MC_TTY_INTERNAL_H */

lib/tty/tty-ncurses.c

@@ -102,6 +102,8 @@ tty_setup_sigwinch (void (*handler) (int))
 #endif /* SA_RESTART */
     sigaction (SIGWINCH, &act, &oact);
 #endif /* SIGWINCH */
+
+    tty_create_winch_pipe ();
 }
 
 /* --------------------------------------------------------------------------------------------- */
@@ -109,9 +111,12 @@ tty_setup_sigwinch (void (*handler) (int))
 static void
 sigwinch_handler (int dummy)
 {
+    ssize_t n = 0;
+
     (void) dummy;
 
-    mc_global.tty.winch_flag = 1;
+    n = write (sigwinch_pipe[1], "", 1);
+    (void) n;
 }
 
 /* --------------------------------------------------------------------------------------------- */

lib/tty/tty-slang.c

@@ -139,6 +139,7 @@ static void
 tty_setup_sigwinch (void (*handler) (int))
 {
     (void) SLsignal (SIGWINCH, handler);
+    tty_create_winch_pipe ();
 }
 
 /* --------------------------------------------------------------------------------------------- */
@@ -146,9 +147,13 @@ tty_setup_sigwinch (void (*handler) (int))
 static void
 sigwinch_handler (int dummy)
 {
+    ssize_t n = 0;
+
     (void) dummy;
 
-    mc_global.tty.winch_flag = 1;
+    n = write (sigwinch_pipe[1], "", 1);
+    (void) n;
+
     (void) SLsignal (SIGWINCH, sigwinch_handler);
 }
 

lib/tty/tty.c

@@ -30,6 +30,7 @@
 
 #include <config.h>
 
+#include <errno.h>
 #include <signal.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -164,6 +165,29 @@ tty_got_interrupt (void)
 
 /* --------------------------------------------------------------------------------------------- */
 
+gboolean
+tty_got_winch (void)
+{
+    gboolean ret = FALSE;
+    ssize_t n;
+
+    /* merge all SIGWINCH events raised to this moment */
+    do
+    {
+        char x[16];
+
+        /* read multiple events at a time  */
+        n = read (sigwinch_pipe[0], &x, sizeof (x));
+        if (n > 0)
+            ret = TRUE;
+    }
+    while (n > 0 || (n == -1 && errno == EINTR));
+
+    return ret;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
 void
 tty_print_one_hline (gboolean single)
 {

lib/tty/tty.h

@@ -80,6 +80,8 @@ extern void tty_enable_interrupt_key (void);
 extern void tty_disable_interrupt_key (void);
 extern gboolean tty_got_interrupt (void);
 
+extern gboolean tty_got_winch (void);
+
 extern void tty_reset_prog_mode (void);
 extern void tty_reset_shell_mode (void);
 

lib/widget/dialog-switch.c

@@ -338,7 +338,8 @@ mc_refresh (void)
     if (mc_global.we_are_background)
         return;
 #endif /* ENABLE_BACKGROUND */
-    if (mc_global.tty.winch_flag == 0)
+
+    if (!tty_got_winch ())
         tty_refresh ();
     else
     {
@@ -355,8 +356,6 @@ dialog_change_screen_size (void)
 {
     GList *d;
 
-    mc_global.tty.winch_flag = 0;
-
     tty_change_screen_size ();
 
 #ifdef HAVE_SLANG

lib/widget/dialog.c

@@ -519,7 +519,7 @@ frontend_dlg_run (WDialog * h)
     {
         int d_key;
 
-        if (mc_global.tty.winch_flag != 0)
+        if (tty_got_winch ())
             dialog_change_screen_size ();
 
         if (is_idle ())

src/execute.c

@@ -531,8 +531,7 @@ toggle_panels (void)
      * Save sigwinch flag that will be reset in mc_refresh() called via update_panels().
      * There is some problem with screen redraw in ncurses-based mc in this situation.
      */
-    was_sigwinch = mc_global.tty.winch_flag;
-    mc_global.tty.winch_flag = 0;
+    was_sigwinch = tty_got_winch ();
 
 #ifdef ENABLE_SUBSHELL
     if (mc_global.tty.use_subshell)
@@ -555,7 +554,7 @@ toggle_panels (void)
         update_xterm_title_path ();
     }
 
-    if (was_sigwinch != 0 || mc_global.tty.winch_flag != 0)
+    if (was_sigwinch != 0 || tty_got_winch ())
         dialog_change_screen_size ();
     else
         repaint_screen ();

src/subshell/common.c

@@ -207,7 +207,7 @@ write_all (int fd, const void *buf, size_t count)
         {
             if (errno == EINTR)
             {
-                if (mc_global.tty.winch_flag != 0)
+                if (tty_got_winch ())
                     tty_change_screen_size ();
 
                 continue;
@@ -545,7 +545,7 @@ feed_subshell (int how, gboolean fail_on_error)
             /* Despite using SA_RESTART, we still have to check for this */
             if (errno == EINTR)
             {
-                if (mc_global.tty.winch_flag != 0)
+                if (tty_got_winch ())
                     tty_change_screen_size ();
 
                 continue;       /* try all over again */
@@ -1211,7 +1211,7 @@ read_subshell_prompt (void)
         {
             if (errno == EINTR)
             {
-                if (mc_global.tty.winch_flag != 0)
+                if (tty_got_winch ())
                     tty_change_screen_size ();
 
                 continue;