Always use Zend signal handling

Being able to choose whether Zend signal handling should be used or not does not
benefit users (or packagers) of PHP in any way. The use of Zend SH is a
purely internal implementation detail, so there is no need for the build config
parameters --{disable,enable}-zend-signals.

By just choosing one way to do things (in this case, always using Zend signal
handling), we can simplify the codebase a bit.

Of course, some platforms do not have the concept of signals and signal handlers
at all. That is why previously, Zend signal handling was automatically disabled
if the platform did not have `sigaction`. In harmony with that, we now guard the
implementation of Zend signal handling with `#ifdef HAVE_SIGACTION`.

Author: alexdowad

Zend/Zend.m4

@@ -303,23 +303,6 @@ AC_MSG_RESULT(done)
 
 AC_CHECK_FUNCS(mremap)
 
-AC_ARG_ENABLE([zend-signals],
-  [AS_HELP_STRING([--disable-zend-signals],
-    [whether to enable zend signal handling])],
-  [ZEND_SIGNALS=$enableval],
-  [ZEND_SIGNALS=yes])
-
-AC_CHECK_FUNCS([sigaction], [], [
-  ZEND_SIGNALS=no
-])
-if test "$ZEND_SIGNALS" = "yes"; then
-	AC_DEFINE(ZEND_SIGNALS, 1, [Use zend signal handling])
-	CFLAGS="$CFLAGS -DZEND_SIGNALS"
-fi
-
-AC_MSG_CHECKING(whether to enable zend signal handling)
-AC_MSG_RESULT($ZEND_SIGNALS)
-
 ])
 
 AC_MSG_CHECKING(whether /dev/urandom exists)

Zend/zend.c

@@ -165,7 +165,7 @@ ZEND_INI_BEGIN()
  	STD_ZEND_INI_BOOLEAN("zend.multibyte", "0", ZEND_INI_PERDIR, OnUpdateBool, multibyte,      zend_compiler_globals, compiler_globals)
  	ZEND_INI_ENTRY("zend.script_encoding",			NULL,		ZEND_INI_ALL,		OnUpdateScriptEncoding)
  	STD_ZEND_INI_BOOLEAN("zend.detect_unicode",			"1",	ZEND_INI_ALL,		OnUpdateBool, detect_unicode, zend_compiler_globals, compiler_globals)
-#ifdef ZEND_SIGNALS
+#ifdef HAVE_SIGACTION
 	STD_ZEND_INI_BOOLEAN("zend.signal_check", "0", ZEND_INI_SYSTEM, OnUpdateBool, check, zend_signal_globals_t, zend_signal_globals)
 #endif
 	STD_ZEND_INI_BOOLEAN("zend.exception_ignore_args",	"0",	ZEND_INI_ALL,		OnUpdateBool, exception_ignore_args, zend_executor_globals, executor_globals)

Zend/zend_execute_API.c

@@ -1302,24 +1302,7 @@ static void zend_set_timeout_ex(zend_long seconds, int reset_signals) /* {{{ */
 # endif
 
 		if (reset_signals) {
-# ifdef ZEND_SIGNALS
 			zend_signal(signo, zend_timeout_handler);
-# else
-			sigset_t sigset;
-#  ifdef HAVE_SIGACTION
-			struct sigaction act;
-
-			act.sa_handler = zend_timeout_handler;
-			sigemptyset(&act.sa_mask);
-			act.sa_flags = SA_RESETHAND | SA_NODEFER;
-			sigaction(signo, &act, NULL);
-#  else
-			signal(signo, zend_timeout_handler);
-#  endif /* HAVE_SIGACTION */
-			sigemptyset(&sigset);
-			sigaddset(&sigset, signo);
-			sigprocmask(SIG_UNBLOCK, &sigset, NULL);
-# endif /* ZEND_SIGNALS */
 		}
 	}
 #endif /* HAVE_SETITIMER */

Zend/zend_signal.c

@@ -36,7 +36,7 @@
 #include <unistd.h>
 #endif
 
-#ifdef ZEND_SIGNALS
+#ifdef HAVE_SIGACTION
 
 #include "zend_signal.h"
 
@@ -441,5 +441,9 @@ ZEND_API void zend_signal_startup(void)
 }
 /* }}} */
 
+ZEND_API void zend_signal_disable_debug(void)
+{
+	SIGG(check) = 0;
+}
 
-#endif /* ZEND_SIGNALS */
+#endif /* HAVE_SIGACTION */

Zend/zend_signal.h

@@ -21,7 +21,7 @@
 #ifndef ZEND_SIGNAL_H
 #define ZEND_SIGNAL_H
 
-#ifdef ZEND_SIGNALS
+#ifdef HAVE_SIGACTION
 
 #include <signal.h>
 
@@ -61,6 +61,8 @@ typedef struct _zend_signal_globals_t {
 	zend_signal_queue_t pstorage[ZEND_SIGNAL_QUEUE_SIZE], *phead, *ptail, *pavail; /* pending queue */
 } zend_signal_globals_t;
 
+# define SIZEOF_ZEND_SIGNAL_GLOBALS sizeof(zend_signal_globals_t)
+
 # ifdef ZTS
 #  define SIGG(v) ZEND_TSRMG_FAST(zend_signal_globals_offset, zend_signal_globals_t *, v)
 BEGIN_EXTERN_C()
@@ -89,11 +91,14 @@ BEGIN_EXTERN_C()
 ZEND_API void zend_signal_startup(void);
 END_EXTERN_C()
 void zend_signal_init(void);
+ZEND_API void zend_signal_disable_debug(void);
 
 ZEND_API int zend_signal(int signo, void (*handler)(int));
 ZEND_API int zend_sigaction(int signo, const struct sigaction *act, struct sigaction *oldact);
 
-#else /* ZEND_SIGNALS */
+#else /* HAVE_SIGACTION */
+
+# define SIZEOF_ZEND_SIGNAL_GLOBALS 0
 
 # define ZEND_SIGNAL_BLOCK_INTERRUPTIONS()
 # define ZEND_SIGNAL_UNBLOCK_INTERRUPTIONS()
@@ -102,10 +107,11 @@ ZEND_API int zend_sigaction(int signo, const struct sigaction *act, struct sigac
 # define zend_signal_deactivate()
 # define zend_signal_startup()
 # define zend_signal_init()
+# define zend_signal_disable_debug()
 
 # define zend_signal(signo, handler)           signal(signo, handler)
 # define zend_sigaction(signo, act, oldact)    sigaction(signo, act, oldact)
 
-#endif /* ZEND_SIGNALS */
+#endif /* HAVE_SIGACTION */
 
 #endif /* ZEND_SIGNAL_H */

configure.ac

@@ -577,6 +577,7 @@ scandir \
 setitimer \
 setenv \
 shutdown \
+sigaction \
 sigprocmask \
 statfs \
 statvfs \

ext/standard/info.c

@@ -848,12 +848,6 @@ PHPAPI ZEND_COLD void php_print_info(int flag)
 		php_info_print_table_row(2, "Thread Safety", "disabled" );
 #endif
 
-#ifdef ZEND_SIGNALS
-		php_info_print_table_row(2, "Zend Signal Handling", "enabled" );
-#else
-		php_info_print_table_row(2, "Zend Signal Handling", "disabled" );
-#endif
-
 		php_info_print_table_row(2, "Zend Memory Manager", is_zend_mm() ? "enabled" : "disabled" );
 
 		{

ext/standard/tests/general_functions/phpinfo.phpt

@@ -31,7 +31,6 @@ Zend Extension Build => API%s
 PHP Extension Build => API%s
 Debug Build => %s
 Thread Safety => %s%A
-Zend Signal Handling => %s
 Zend Memory Manager => %s
 Zend Multibyte Support => %s
 IPv6 Support => %s

main/main.c

@@ -1751,10 +1751,7 @@ int php_request_startup(void)
 
 		zend_activate();
 		sapi_activate();
-
-#ifdef ZEND_SIGNALS
 		zend_signal_activate();
-#endif
 
 		if (PG(max_input_time) == -1) {
 			zend_set_timeout(EG(timeout_seconds), 1);
@@ -1903,9 +1900,7 @@ void php_request_shutdown(void *dummy)
 	} zend_end_try();
 
 	/* 16. Deactivate Zend signals */
-#ifdef ZEND_SIGNALS
 	zend_signal_deactivate();
-#endif
 
 #ifdef PHP_WIN32
 	if (PG(com_initialized)) {
@@ -2729,9 +2724,7 @@ PHPAPI void php_reserve_tsrm_memory(void)
 		TSRM_ALIGNED_SIZE(sizeof(zend_php_scanner_globals)) +
 		TSRM_ALIGNED_SIZE(sizeof(zend_ini_scanner_globals)) +
 		TSRM_ALIGNED_SIZE(sizeof(virtual_cwd_globals)) +
-#ifdef ZEND_SIGNALS
-		TSRM_ALIGNED_SIZE(sizeof(zend_signal_globals_t)) +
-#endif
+		TSRM_ALIGNED_SIZE(SIZEOF_ZEND_SIGNAL_GLOBALS) +
 		TSRM_ALIGNED_SIZE(zend_mm_globals_size()) +
 		TSRM_ALIGNED_SIZE(zend_gc_globals_size()) +
 		TSRM_ALIGNED_SIZE(sizeof(php_core_globals)) +

sapi/apache2handler/sapi_apache2.c

@@ -739,20 +739,16 @@ static void php_apache_child_init(apr_pool_t *pchild, server_rec *s)
 	apr_pool_cleanup_register(pchild, NULL, php_apache_child_shutdown, apr_pool_cleanup_null);
 }
 
-#ifdef ZEND_SIGNALS
 static void php_apache_signal_init(apr_pool_t *pchild, server_rec *s)
 {
 	zend_signal_init();
 }
-#endif
 
 void php_ap2_register_hook(apr_pool_t *p)
 {
 	ap_hook_pre_config(php_pre_config, NULL, NULL, APR_HOOK_MIDDLE);
 	ap_hook_post_config(php_apache_server_startup, NULL, NULL, APR_HOOK_MIDDLE);
 	ap_hook_handler(php_handler, NULL, NULL, APR_HOOK_MIDDLE);
-#ifdef ZEND_SIGNALS
 	ap_hook_child_init(php_apache_signal_init, NULL, NULL, APR_HOOK_MIDDLE);
-#endif
 	ap_hook_child_init(php_apache_child_init, NULL, NULL, APR_HOOK_MIDDLE);
 }

sapi/fuzzer/fuzzer-sapi.c

@@ -147,11 +147,9 @@ int fuzzer_request_startup()
 		return FAILURE;
 	}
 
-#ifdef ZEND_SIGNALS
 	/* Some signal handlers will be overridden,
 	 * don't complain about them during shutdown. */
-	SIGG(check) = 0;
-#endif
+	zend_signal_disable_debug();
 
 	return SUCCESS;
 }

sapi/litespeed/lsapi_main.c

@@ -1483,11 +1483,7 @@ int main( int argc, char * argv[] )
     php_tsrm_startup();
 #endif
 
-#if PHP_MAJOR_VERSION >= 7
-#if defined(ZEND_SIGNALS) || PHP_MINOR_VERSION > 0
     zend_signal_startup();
-#endif
-#endif
 
     if (argc > 1 ) {
         if ( parse_opt( argc, argv, &climode,

sapi/phpdbg/phpdbg.h

@@ -44,7 +44,7 @@
 #include "zend_ini_scanner.h"
 #include "zend_stream.h"
 #include "zend_signal.h"
-#if !defined(_WIN32) && !defined(ZEND_SIGNALS)
+#if !defined(_WIN32)
 #	include <signal.h>
 #elif defined(PHP_WIN32)
 #	include "win32/signal.h"