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, 93 insertions, 0 deletions

diff --git a/signal.h b/signal.h
new file mode 100644
index 00000000..111c6265
--- /dev/null
+++ b/signal.h
@@ -0,0 +1,93 @@
+/* Copyright 2013-2014
+ * Kaz Kylheku <kaz@kylheku.com>
+ * Vancouver, Canada
+ * All rights reserved.
+ *
+ * BSD License:
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in
+ *      the documentation and/or other materials provided with the
+ *      distribution.
+ *   3. The name of the author may not be used to endorse or promote
+ *      products derived from this software without specific prior
+ *      written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+
+#if HAVE_POSIX_SIGS
+
+#define sig_save_enable                         \
+  do {                                          \
+    int sig_save = async_sig_enabled;           \
+    async_sig_enabled = 1;                      \
+    if (!sig_save)                              \
+      sig_check();                              \
+    {                                           \
+      typedef void v_o_i_d
+
+#define sig_restore_enable                      \
+      do { } while (0);                         \
+    }                                           \
+    async_sig_enabled = sig_save;               \
+  } while(0)
+
+#define sig_save_disable                        \
+  do {                                          \
+    int sig_save = async_sig_enabled;           \
+    async_sig_enabled = 1;                      \
+    {                                           \
+      typedef void v_o_i_d
+
+#define sig_restore_disable                     \
+      do { } while (0);                         \
+    }                                           \
+    async_sig_enabled = sig_save;               \
+    if (sig_save)                               \
+      sig_check();                              \
+  } while(0)
+    
+typedef struct {
+  jmp_buf jb;
+  sig_atomic_t se;
+  int rv;
+} extended_jmp_buf;
+
+#define extended_setjmp(EJB)                    \
+  (sigsetjmp((EJB).jb, 1)                       \
+   ? (async_sig_enabled = (EJB).se, (EJB).rv)   \
+   : ((EJB).se = async_sig_enabled, 0))
+
+#define extended_longjmp(EJB, ARG)              \
+  ((EJB).rv = (ARG), longjmp((EJB).jb, 1))
+
+#else
+
+#define sig_save_enable do {
+#define sig_save_disable do {
+
+#define sig_restore_enable do { } while (0); } while (0)
+#define sig_restore_disable do { } while (0); } while (0)
+
+tyedef jmp_buf extended_jmp_buf;
+#define extended_setjmp(EJB) setjmp(EJB)
+#define extended_longjmp(EJB, ARG) longjmp(EJB, ARG)
+
+#endif
+
+extern volatile sig_atomic_t async_sig_enabled;
+
+void sig_init(void);
+val set_sig_handler(val signo, val lambda);
+val get_sig_handler(val signo);
+val sig_check(void);