• Paul Eggert's avatar
    Signal-handler cleanup. · 2fe28299
    Paul Eggert authored
    Emacs's signal handlers were written in the old 4.2BSD style with
    sigblock and sigmask and so forth, and this led to some
    inefficiencies and confusion.  Rewrite these to use
    pthread_sigmask etc. without copying signal sets around.  Also,
    get rid of the confusing macros 'SIGNAL_THREAD_CHECK' and
    'signal', and instead use functions that do not attempt to take
    over the system name space.  This patch causes Emacs's text
    segment to shrink by 0.7% on my platform, Fedora 17 x86-64.
    * configure.ac (PTY_OPEN, PTY_TTY_NAME_SPRINTF):
    Adjust to syssignal.h changes.
    (SIGNAL_H_AB): Remove; no longer needed.
    * src/alloc.c, src/emacsgtkfixed.c, src/nsfns.m, src/widget.c, src/xmenu.c:
    Do not include <signal.h> or "syssignal.h", as these
    modules do not use signals.
    * src/atimer.c, src/callproc.c, src/data.c, src/dispnew.c, src/emacs.c:
    * src/floatfns.c, src/gtkutil.c, src/keyboard.c, src/process.c, src/sound.c:
    * src/sysdep.c, src/term.c, src/xterm.c:
    Do not include <signal.h>, as "syssignal.h" does that for us now.
    * src/atimer.c (sigmask_atimers): New function.
    (block_atimers, unblock_atimers): New functions,
    replacing the old macros BLOCK_ATIMERS and UNBLOCK_ATIMERS.
    All uses replaced.
    * src/conf_post.h [SIGNAL_H_AHB]: Do not include <signal.h>;
    no longer needed here.
    * src/emacs.c (main): Inspect existing signal handler with sigaction,
    so that there's	no need to block and unblock SIGHUP.
    * src/sysdep.c (struct save_signal): New member 'action', replacing
    old member 'handler'.
    (save_signal_handlers, restore_signal_handlers):
    Use sigaction instead of 'signal' to save and restore.
    (get_set_sighandler, set_sighandler) [!WINDOWSNT]:
    New function.  All users of 'signal' modified to use set_sighandler
    if they're writeonly, and to use sys_signal if they're read+write.
    (emacs_sigaction_init, forwarded_signal): New functions.
    (sys_signal): Remove.  All uses replaced by calls to sigaction
    and emacs_sigaction_init, or by direct calls to 'signal'.
    (sys_sigmask) [!__GNUC__]: Remove; no longer needed.
    (sys_sigblock, sys_sigunblock, sys_sigsetmask): Remove;
    all uses replaced by pthread_sigmask etc. calls.
    * src/syssignal.h: Include <signal.h>.
    (emacs_sigaction_init, forwarded_signal): New decls.
    (SIGMASKTYPE): Remove.  All uses replaced by its definiens, sigset_t.
    (SIGEMPTYMASK): Remove; all uses replaced by its definiens, empty_mask.
    (sigmask, sys_sigmask): Remove; no longer needed.
    (sigpause): Remove.  All uses replaced by its definiens, sigsuspend.
    (sigblock, sigunblock, sigfree):
    (sigsetmask) [!defined sigsetmask]:
    Remove.  All uses replaced by pthread_sigmask.
    (signal): Remove.  Its remaining uses (with SIG_DFL and SIG_IGN)
    no longer need to be replaced, and its typical old uses
    are now done via emacs_sigaction_init and sigaction.
    (sys_sigblock, sys_sigunblock, sys_sigsetmask): Remove decls.
    (sys_sigdel): Remove; unused.
    (NSIG): Remove a FIXME; the code's fine.  Remove an unnecessary ifdef.
    Fixes: debbugs:12327
emacs.c 73.6 KB