First cut at signal handling support.

* Makefile (OBJS-y): Include signal.o if have_posix_sigs is "y".

* configure (have_posix_sigs): New variable, set by detecting POSIX
signal stuff.

* dep.mk: Regenerated.

* arith.c, debug.c, eval.c, filter.c, hash.c, match.c, parser.y,
parser.l, rand.c, regex.c, syslog.c, txr.c, utf8.c: Include new
signal.h header, now required by unwind, and the <signal.h> system
header.

* eval.c (exit_wrap): New function.
(eval_init): New functions registered as intrinsics: exit_wrap,
set_sig_handler, get_sig_handler, sig_check.

* gc.c (release): Unused functions removed.

* gc.h (release): Declaration removed.

* lib.c (init): Call sig_init.

* stream.c (set_putc, se_getc, se_fflush): New static functions.
(stdio_put_char_callback, stdio_get_char_callback, stdio_put_byte,
stdio_flush, stdio_get_byte): Use new functions to enable
signals when blocked on I/O.
(tail_strategy): Allow signals across sleep.
(pipev_close): Allow signals across waitpid.
(se_pclose): New static function.
(pipe_close): Use new function to enable signals across pclose.

* unwind.c (uw_unwind_to_exit_point): use extended_longjmp instead of
longjmp.

* unwind.h (struct uw_block, struct uw_catch): jb member changes from
jmp_buf to extended_jmp_buf.
(uw_block_begin, uw_simple_catch_begin, uw_catch_begin): Use
extended_setjmp instead of setjmp.

* signal.c: New file.

* signal.h: New file.

1 files changed, 31 insertions, 0 deletions

diff --git a/configure b/configure
index 47e88ba9..7ab6931d 100755
--- a/configure
+++ b/configure
@@ -100,6 +100,7 @@ have_patch=
 have_unistd=
 have_timegm=
 have_syslog=
+have_posix_sigs=
 need_svid_source=
 need_bsd_source=
 
@@ -576,6 +577,9 @@ tool_prefix := $tool_prefix
 # do we compile in syslog support?
 have_syslog := $have_syslog
 
+# do we modern posix signal handling?
+have_posix_sigs := $have_posix_sigs
+
 # do we compile in debug support?
 debug_support := $debug_support
 
@@ -1437,6 +1441,33 @@ else
   have_syslog=y
 fi
 
+printf "Checking for reasonably modern POSIX signal handling ... "
+
+cat > conftest.c <<!
+#include <signal.h>
+#include <setjmp.h>
+
+int main(void)
+{
+  sigjmp_buf jb;
+  static struct sigaction old, new;
+  static sigset_t olds, news;
+  sigaction(0, &new, &old);
+  sigprocmask(SIG_BLOCK, &news, &olds);
+  if (!sigsetjmp(jb, 1)) 
+    siglongjmp(jb, 1);
+  return 0;
+}
+!
+rm -f conftest
+if ! $make conftest > conftest.err 2>&1 || ! [ -x conftest ] ; then
+  printf "no\n"
+else
+  printf "yes\n"
+  printf "#define HAVE_POSIX_SIGS 1\n" >> config.h
+  have_posix_sigs=y
+fi
+
 #
 # Dependent variables
 #