mutt_signal.c

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#include "config.h"
#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stddef.h>
#include "mutt/lib.h"
#include "config/lib.h"
#include "core/lib.h"
#include "gui/lib.h"
#include "attach/lib.h"
#if defined(USE_DEBUG_GRAPHVIZ) || defined(USE_DEBUG_BACKTRACE)
#include "debug/lib.h"
#endif

static int IsEndwin = 0;

static void curses_signal_handler(int sig)
{
  int save_errno = errno;
  enum MuttCursorState old_cursor = MUTT_CURSOR_VISIBLE;
 
  switch (sig)
  {
    case SIGTSTP: /* user requested a suspend */
    {
      const bool c_suspend = cs_subset_bool(NeoMutt->sub, "suspend");
      if (!c_suspend)
        break;
      IsEndwin = isendwin();
      old_cursor = mutt_curses_set_cursor(MUTT_CURSOR_VISIBLE);
      if (!IsEndwin)
        endwin();
      kill(0, SIGSTOP);
    }
      FALLTHROUGH;
 
    case SIGCONT:
      if (!IsEndwin)
        refresh();
      mutt_curses_set_cursor(old_cursor);
      /* We don't receive SIGWINCH when suspended; however, no harm is done by
       * just assuming we received one, and triggering the 'resize' anyway. */
      SigWinch = true;
      break;
 
    case SIGWINCH:
      SigWinch = true;
      break;
 
    case SIGINT:
      SigInt = true;
      break;
  }
  errno = save_errno;
}

static void curses_exit_handler(int sig)
{
  mutt_curses_set_cursor(MUTT_CURSOR_VISIBLE);
  endwin(); /* just to be safe */
  mutt_temp_attachments_cleanup();
  mutt_sig_exit_handler(sig); /* DOES NOT RETURN */
}

static void curses_segv_handler(int sig)
{
  mutt_curses_set_cursor(MUTT_CURSOR_VISIBLE);
  endwin(); /* just to be safe */
#ifdef USE_DEBUG_BACKTRACE
  show_backtrace();
#endif
#ifdef USE_DEBUG_GRAPHVIZ
  dump_graphviz("segfault", NULL);
#endif
 
  // Chain the old SEGV handler, it could have been set by ASAN
  if (OldSegvHandler)
    OldSegvHandler(sig);
 
  struct sigaction act = { 0 };
  sigemptyset(&act.sa_mask);
  act.sa_flags = 0;
  act.sa_handler = SIG_DFL;
  sigaction(sig, &act, NULL);
 
  // Re-raise the signal to give outside handlers a chance to deal with it
  raise(sig);
}

void mutt_signal_init(void)
{
  mutt_sig_init(curses_signal_handler, curses_exit_handler, curses_segv_handler);
}