degesch: add backlog/scrollback functionality
Finally! I went with possibly the simplest solution, which is to run less, instead of badly reimplementing its functionality.
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27f185e8aa
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223
degesch.c
223
degesch.c
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@ -1364,6 +1364,8 @@ struct app_context
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bool awaiting_mirc_escape; ///< Awaiting a mIRC attribute escape
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char char_buf[MB_LEN_MAX + 1]; ///< Buffered multibyte char
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size_t char_buf_len; ///< How much of an MB char is buffered
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bool running_backlog_helper; ///< Running a backlog helper
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}
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*g_ctx;
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@ -1640,6 +1642,10 @@ static struct config_schema g_config_behaviour[] =
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.type = CONFIG_ITEM_BOOLEAN,
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.default_ = "off",
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.on_change = on_config_logging_change },
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{ .name = "backlog_helper",
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.comment = "Shell command to display a buffer's history",
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.type = CONFIG_ITEM_STRING,
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.default_ = "\"LESSSECURE=1 less -M -R +G\"" },
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{ .name = "save_on_quit",
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.comment = "Save configuration before quitting",
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.type = CONFIG_ITEM_BOOLEAN,
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@ -2839,11 +2845,18 @@ log_formatter (struct app_context *ctx,
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&& buffer == ctx->current_buffer->server->buffer))
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can_leak = true;
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if (buffer == ctx->current_buffer)
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bool displayed = true;
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if (ctx->running_backlog_helper)
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// Another process is using the terminal
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displayed = false;
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else if (buffer == ctx->current_buffer)
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buffer_line_display (ctx, line, false);
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else if (!ctx->isolate_buffers && can_leak)
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buffer_line_display (ctx, line, true);
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else
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displayed = false;
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if (!displayed)
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{
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buffer->unseen_messages_count++;
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if (flags & BUFFER_LINE_HIGHLIGHT)
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@ -2957,6 +2970,8 @@ buffer_open_log_file (struct app_context *ctx, struct buffer *buffer)
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if (!(buffer->log_file = fopen (path.str, "ab")))
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log_global_error (ctx, "Couldn't open log file `#s': #s",
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path.str, strerror (errno));
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else
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set_cloexec (fileno (buffer->log_file));
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str_free (&path);
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}
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@ -8807,6 +8822,38 @@ make_completions (struct app_context *ctx, char *line, int start, int end)
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// --- Common code for user actions --------------------------------------------
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static void
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suspend_terminal (struct app_context *ctx)
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{
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#ifdef HAVE_READLINE
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rl_deprep_terminal ();
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#elif defined (HAVE_EDITLINE)
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el_set (ctx->input.editline, EL_PREP_TERM, 0);
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#endif
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input_hide (&ctx->input);
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poller_fd_reset (&ctx->tty_event);
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// TODO: also disable the date change timer
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}
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static void
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resume_terminal (struct app_context *ctx)
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{
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#ifdef HAVE_READLINE
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rl_prep_terminal (true);
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#elif defined (HAVE_EDITLINE)
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el_set (ctx->input.editline, EL_PREP_TERM, 1);
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#endif
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// In theory we could just print all unseen messages but this is safer
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buffer_print_backlog (ctx, ctx->current_buffer);
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// Now it's safe to process any user input
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poller_fd_set (&ctx->tty_event, POLLIN);
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input_show (&ctx->input);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static bool
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redraw_screen (struct app_context *ctx)
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{
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@ -8849,6 +8896,59 @@ await_mirc_escape (struct app_context *ctx)
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ctx->char_buf_len = 0;
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}
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static void
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exec_backlog_helper (const char *command, FILE *backlog)
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{
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dup2 (fileno (backlog), STDIN_FILENO);
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// Put the child into a new foreground process group
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hard_assert (setpgid (0, 0)!= -1);
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hard_assert (tcsetpgrp (STDOUT_FILENO, getpgid (0)) != -1);
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execl ("/bin/sh", "/bin/sh", "-c", command, NULL);
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print_error ("%s: %s", "Failed to launch backlog helper", strerror (errno));
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_exit (EXIT_FAILURE);
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}
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static void
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display_backlog (struct app_context *ctx)
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{
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hard_assert (!ctx->running_backlog_helper);
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FILE *backlog = tmpfile ();
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set_cloexec (fileno (backlog));
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// TODO: retrieve the lines with formatting
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for (struct buffer_line *line = ctx->current_buffer->lines;
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line; line = line->next)
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buffer_line_write_to_log (ctx, line, backlog);
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rewind (backlog);
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suspend_terminal (ctx);
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pid_t child = fork ();
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if (child == 0)
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exec_backlog_helper (get_config_string
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(ctx->config.root, "behaviour.backlog_helper"), backlog);
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if (child == -1)
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{
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int saved_errno = errno;
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resume_terminal (ctx);
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log_global_error (ctx, "#s: #s",
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"Failed to launch backlog helper", strerror (saved_errno));
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}
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else
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{
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// Make sure the child has its own process group
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(void) setpgid (child, child);
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ctx->running_backlog_helper = true;
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}
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fclose (backlog);
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}
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static void
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bind_common_keys (struct app_context *ctx)
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{
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@ -8866,6 +8966,8 @@ bind_common_keys (struct app_context *ctx)
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input_bind (self, key_f5, "previous-buffer");
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if (key_f6)
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input_bind (self, key_f6, "next-buffer");
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if (key_ppage)
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input_bind (self, key_ppage, "display-backlog");
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if (clear_screen)
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input_bind_control (self, 'l', "redraw-screen");
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@ -8906,6 +9008,17 @@ on_readline_next_buffer (int count, int key)
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return 0;
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}
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static int
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on_readline_display_backlog (int count, int key)
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{
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(void) count;
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(void) key;
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struct app_context *ctx = g_ctx;
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display_backlog (ctx);
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return 0;
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}
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static int
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on_readline_redraw_screen (int count, int key)
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{
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@ -8998,6 +9111,7 @@ app_readline_init (void)
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rl_add_defun ("previous-buffer", on_readline_previous_buffer, -1);
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rl_add_defun ("next-buffer", on_readline_next_buffer, -1);
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rl_add_defun ("goto-buffer", on_readline_goto_buffer, -1);
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rl_add_defun ("display-backlog", on_readline_display_backlog, -1);
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rl_add_defun ("redraw-screen", on_readline_redraw_screen, -1);
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rl_add_defun ("insert-attribute", on_readline_insert_attribute, -1);
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rl_add_defun ("send-line", on_readline_return, -1);
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@ -9057,6 +9171,15 @@ on_editline_next_buffer (EditLine *editline, int key)
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return CC_NORM;
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}
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static unsigned char
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on_editline_display_backlog (EditLine *editline, int key)
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{
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(void) editline;
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(void) key;
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display_backlog (g_ctx);
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}
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static unsigned char
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on_editline_redraw_screen (EditLine *editline, int key)
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{
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@ -9173,6 +9296,7 @@ app_editline_init (struct input *self)
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{ "goto-buffer", "Go to buffer", on_editline_goto_buffer },
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{ "previous-buffer", "Previous buffer", on_editline_previous_buffer },
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{ "next-buffer", "Next buffer", on_editline_next_buffer },
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{ "display-backlog", "Display backlog", on_editline_display_backlog },
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{ "redraw-screen", "Redraw screen", on_editline_redraw_screen },
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{ "insert-attribute", "mIRC formatting", on_editline_insert_attribute },
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{ "send-line", "Send line", on_editline_return },
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@ -9376,29 +9500,34 @@ static volatile sig_atomic_t g_termination_requested;
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static volatile sig_atomic_t g_winch_received;
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static void
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sigterm_handler (int signum)
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postpone_signal_handling (char id)
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{
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(void) signum;
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g_termination_requested = true;
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int original_errno = errno;
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if (write (g_signal_pipe[1], "t", 1) == -1)
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if (write (g_signal_pipe[1], &id, 1) == -1)
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soft_assert (errno == EAGAIN);
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errno = original_errno;
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}
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static void
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sigwinch_handler (int signum)
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signal_superhandler (int signum)
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{
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(void) signum;
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g_winch_received = true;
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int original_errno = errno;
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if (write (g_signal_pipe[1], "w", 1) == -1)
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soft_assert (errno == EAGAIN);
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errno = original_errno;
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switch (signum)
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{
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case SIGWINCH:
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g_winch_received = true;
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postpone_signal_handling ('w');
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break;
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case SIGINT:
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case SIGTERM:
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g_termination_requested = true;
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postpone_signal_handling ('t');
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break;
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case SIGCHLD:
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postpone_signal_handling ('c');
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break;
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default:
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hard_assert (!"unhandled signal");
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}
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}
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static void
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@ -9418,28 +9547,76 @@ setup_signal_handlers (void)
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signal (SIGPIPE, SIG_IGN);
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// So that we can write to the terminal while we're running a backlog
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// helper. This is also inherited by the child so that it doesn't stop
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// when it calls tcsetpgrp().
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signal (SIGTTOU, SIG_IGN);
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struct sigaction sa;
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sa.sa_flags = SA_RESTART;
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sa.sa_handler = sigwinch_handler;
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sa.sa_handler = signal_superhandler;
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sigemptyset (&sa.sa_mask);
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if (sigaction (SIGWINCH, &sa, NULL) == -1)
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exit_fatal ("sigaction: %s", strerror (errno));
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sa.sa_handler = sigterm_handler;
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if (sigaction (SIGINT, &sa, NULL) == -1
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|| sigaction (SIGTERM, &sa, NULL) == -1)
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if (sigaction (SIGWINCH, &sa, NULL) == -1
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|| sigaction (SIGINT, &sa, NULL) == -1
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|| sigaction (SIGTERM, &sa, NULL) == -1
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|| sigaction (SIGCHLD, &sa, NULL) == -1)
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exit_fatal ("sigaction: %s", strerror (errno));
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}
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// --- I/O event handlers ------------------------------------------------------
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static bool
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try_reap_child (struct app_context *ctx)
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{
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int status;
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pid_t zombie = waitpid (-1, &status, WNOHANG | WUNTRACED);
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if (zombie == -1)
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{
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if (errno == ECHILD) return false;
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if (errno == EINTR) return true;
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exit_fatal ("%s: %s", "waitpid", strerror (errno));
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}
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if (!zombie)
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return false;
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if (!ctx->running_backlog_helper)
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{
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print_debug ("an unknown child has died");
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return true;
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}
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if (WIFSTOPPED (status))
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{
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// We could also send SIGCONT but what's the point
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kill (-zombie, SIGKILL);
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return true;
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}
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ctx->running_backlog_helper = false;
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hard_assert (tcsetpgrp (STDOUT_FILENO, getpgid (0)) != -1);
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resume_terminal (ctx);
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if (WIFSIGNALED (status))
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log_global_error (ctx,
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"Child died from signal #d", WTERMSIG (status));
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else if (WIFEXITED (status) && WEXITSTATUS (status) != 0)
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log_global_error (ctx,
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"Child returned status #d", WEXITSTATUS (status));
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return true;
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}
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static void
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on_signal_pipe_readable (const struct pollfd *fd, struct app_context *ctx)
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{
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char dummy;
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(void) read (fd->fd, &dummy, 1);
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// Reap all dead children (since the signal pipe may overflow etc. we run
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// waitpid() in a loop to return all the zombies it knows about).
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while (try_reap_child (ctx))
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;
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if (g_termination_requested && !ctx->quitting)
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// TODO: this way we don't send a QUIT message but just close the
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// connection from our side and wait for a full close.
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