create only one timer per thread

Author: dunglas

Zend/zend.c

@@ -35,6 +35,7 @@
 #include "zend_attributes.h"
 #include "zend_observer.h"
 #include "zend_fibers.h"
+#include "zend_timer.h"
 #include "Optimizer/zend_optimizer.h"
 
 static size_t global_map_ptr_last = 0;
@@ -817,10 +818,60 @@ static void executor_globals_dtor(zend_executor_globals *executor_globals) /* {{
 }
 /* }}} */
 
+# ifdef ZEND_TIMER
+static void zend_timer_create() /* {{{ */
+{
+	struct sigevent sev;
+	sev.sigev_notify = SIGEV_THREAD_ID;
+	sev.sigev_value.sival_ptr = &EG(timer);
+	// The chosen signal must:
+	// 1. not be used internally by libc
+	// 2. be allowed to happen spuriously without consequences
+	// 3. not be commonly used by applications, this excludes SIGALRM, SIGUSR1 and SIGUSR2
+	// 4. not be used by profilers, this excludes SIGPROF
+	// 5. not be used internally by runtimes of programs that can embed PHP, this excludes SIGURG, which is used by Go
+	sev.sigev_signo = SIGIO;
+	sev.sigev_notify_thread_id = (pid_t) syscall(SYS_gettid);
+
+	int errn = timer_create(CLOCK_THREAD_CPUTIME_ID, &sev, &EG(timer));
+	if (errn != 0) {
+		EG(timer) = 0;
+
+		zend_strerror_noreturn(E_ERROR, errn, "Could not create timer");
+	}
+
+#  ifdef TIMER_DEBUG
+		fprintf(stderr, "Timer %#jx created on thread %d\n", (uintmax_t) EG(timer), sev.sigev_notify_thread_id);
+#  endif
+}
+/* }}} */
+# endif
+
 static void zend_new_thread_end_handler(THREAD_T thread_id) /* {{{ */
 {
 	zend_copy_ini_directives();
 	zend_ini_refresh_caches(ZEND_INI_STAGE_STARTUP);
+#ifdef ZEND_TIMER
+	zend_timer_create();
+#endif
+}
+/* }}} */
+
+static void zend_thread_shutdown_handler(void) { /* {{{ */
+	zend_interned_strings_dtor();
+
+# ifdef ZEND_TIMER
+	timer_t timer = EG(timer);
+
+	if (timer == 0) return;
+
+	int errn = timer_delete(EG(timer));
+	if (errn != 0) zend_strerror_noreturn(E_ERROR, errn, "Could not delete timer");
+
+#  ifdef TIMER_DEBUG
+	fprintf(stderr, "Timer %#jx deleted on thread %d\n", (uintmax_t) EG(timer), (pid_t) syscall(SYS_gettid));
+#  endif
+# endif
 }
 /* }}} */
 #endif
@@ -1026,7 +1077,7 @@ void zend_startup(zend_utility_functions *utility_functions) /* {{{ */
 
 #ifdef ZTS
 	tsrm_set_new_thread_end_handler(zend_new_thread_end_handler);
-	tsrm_set_shutdown_handler(zend_interned_strings_dtor);
+	tsrm_set_shutdown_handler(zend_thread_shutdown_handler);
 #endif
 }
 /* }}} */
@@ -1092,6 +1143,10 @@ zend_result zend_post_startup(void) /* {{{ */
 	executor_globals_ctor(executor_globals);
 	global_persistent_list = &EG(persistent_list);
 	zend_copy_ini_directives();
+
+# ifdef ZEND_TIMER
+	zend_timer_create();
+# endif
 #else
 	global_map_ptr_last = CG(map_ptr_last);
 #endif
@@ -1612,6 +1667,15 @@ ZEND_API ZEND_COLD ZEND_NORETURN void zend_error_noreturn(int type, const char *
 	abort();
 }
 
+ZEND_API ZEND_COLD void zend_strerror_noreturn(int type, int errn, const char *message)
+{
+	char buf[1024];
+	if (!strerror_r(errn, buf, sizeof(buf)))
+		zend_error_noreturn(type, "%s: %d", message, errn);
+
+	zend_error_noreturn(type, "%s: %s (%d)", message, buf, errn);
+}
+
 ZEND_API ZEND_COLD void zend_error_zstr(int type, zend_string *message) {
 	zend_string *filename;
 	uint32_t lineno;

Zend/zend.h

@@ -353,6 +353,9 @@ ZEND_API ZEND_COLD void zend_value_error(const char *format, ...) ZEND_ATTRIBUTE
 
 ZEND_COLD void zenderror(const char *error);
 
+/* For internal C errors */
+ZEND_API ZEND_COLD void zend_strerror_noreturn(int type, int errn, const char *message);
+
 /* The following #define is used for code duality in PHP for Engine 1 & 2 */
 #define ZEND_STANDARD_CLASS_DEF_PTR zend_standard_class_def
 extern ZEND_API zend_class_entry *zend_standard_class_def;

Zend/zend_execute_API.c

@@ -37,22 +37,7 @@
 #include "zend_weakrefs.h"
 #include "zend_inheritance.h"
 #include "zend_observer.h"
-#ifdef HAVE_SYS_TIME_H
-#include <sys/time.h>
-#endif
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-#if defined(ZTS) && defined(HAVE_TIMER_CREATE)
-#include <time.h>
-#include <sys/syscall.h>
-#include <sys/types.h>
-// Musl Libc defines this macro, glibc does not
-// According to "man 2 timer_create" this field should always be available, but it's not
-# ifndef sigev_notify_thread_id
-# define sigev_notify_thread_id _sigev_un._tid
-# endif
-#endif
+#include "zend_timer.h"
 
 ZEND_API void (*zend_execute_ex)(zend_execute_data *execute_data);
 ZEND_API void (*zend_execute_internal)(zend_execute_data *execute_data, zval *return_value);
@@ -181,23 +166,6 @@ void init_executor(void) /* {{{ */
 	EG(vm_interrupt) = 0;
 	EG(timed_out) = 0;
 
-#if defined(ZTS) && defined(HAVE_TIMER_CREATE)
-	struct sigevent sev;
-	sev.sigev_notify = SIGEV_THREAD_ID;
-	sev.sigev_value.sival_ptr = &EG(timer);
-	sev.sigev_signo = SIGIO;
-	sev.sigev_notify_thread_id = (pid_t) syscall(SYS_gettid);
-
-	if (timer_create(CLOCK_THREAD_CPUTIME_ID, &sev, &EG(timer)) != 0) {
-# ifdef TIMER_DEBUG
-		fprintf(stderr, "error %d while creating timer %#jx on thread %d\n", errno, (uintmax_t) EG(timer), (pid_t) syscall(SYS_gettid));
-# endif
-	}
-# ifdef TIMER_DEBUG
-	else fprintf(stderr, "timer %#jx created on thread %d\n", (uintmax_t) EG(timer), syscall(SYS_gettid));
-# endif
-#endif
-
 	EG(exception) = NULL;
 	EG(prev_exception) = NULL;
 
@@ -413,6 +381,26 @@ ZEND_API void zend_shutdown_executor_values(bool fast_shutdown)
 	zend_objects_store_free_object_storage(&EG(objects_store), fast_shutdown);
 }
 
+#ifdef ZEND_TIMER
+static void zend_timer_settime(zend_long seconds) /* {{{ }*/
+{
+	timer_t timer = EG(timer);
+	if (timer == 0) zend_error_noreturn(E_ERROR, "Timer not created");
+
+	struct itimerspec its;
+	its.it_value.tv_sec = seconds;
+	its.it_value.tv_nsec = its.it_interval.tv_sec = its.it_interval.tv_nsec = 0;
+
+	int errn = timer_settime(timer, 0, &its, NULL);
+	if (errn != 0) zend_strerror_noreturn(E_ERROR, errn, "Could not set timer");
+
+# ifdef TIMER_DEBUG
+	fprintf(stderr, "Timer %#jx set on thread %d (%ld seconds)\n", (uintmax_t) timer, (pid_t) syscall(SYS_gettid), seconds);
+# endif
+}
+/* }}} */
+#endif
+
 void shutdown_executor(void) /* {{{ */
 {
 	zend_string *key;
@@ -423,17 +411,6 @@ void shutdown_executor(void) /* {{{ */
 	bool fast_shutdown = is_zend_mm() && !EG(full_tables_cleanup);
 #endif
 
-#if defined(ZTS) && defined(HAVE_TIMER_CREATE)
-	if (timer_delete(EG(timer)) != 0) {
-# ifdef TIMER_DEBUG
-		fprintf(stderr, "error %d while deleting timer %#jx on thread %d\n", errno, (uintmax_t) EG(timer), (pid_t) syscall(SYS_gettid));
-# endif
-	}
-# ifdef TIMER_DEBUG
-	else fprintf(stderr, "timer %#jx deleted on thread %d\n", (uintmax_t) EG(timer), (pid_t) syscall(SYS_gettid));
-# endif
-#endif
-
 	zend_try {
 		zend_stream_shutdown();
 	} zend_end_try();
@@ -1352,7 +1329,7 @@ ZEND_API ZEND_NORETURN void ZEND_FASTCALL zend_timeout(void) /* {{{ */
 /* }}} */
 
 #ifndef ZEND_WIN32
-# if defined(ZTS) && defined(HAVE_TIMER_CREATE)
+# ifdef ZEND_TIMER
 static void zend_timeout_handler(int dummy, siginfo_t *si, void *uc) /* {{{ */
 {
 	if (si->si_value.sival_ptr != &EG(timer)) {
@@ -1465,25 +1442,8 @@ static void zend_set_timeout_ex(zend_long seconds, bool reset_signals) /* {{{ */
 		zend_error_noreturn(E_ERROR, "Could not queue new timer");
 		return;
 	}
-#elif defined(ZTS) && defined(HAVE_TIMER_CREATE)
-	timer_t timer = EG(timer);
-	struct itimerspec its;
-
-	its.it_value.tv_sec = seconds;
-	its.it_value.tv_nsec = 0;
-	its.it_interval.tv_sec = 0;
-	its.it_interval.tv_nsec = 0;
-
-	if (timer_settime(timer, 0, &its, NULL) != 0) {
-#ifdef TIMER_DEBUG
-		fprintf(stderr, "unable to set timer %#jx on thread %d\n", (uintmax_t) timer, (pid_t) syscall(SYS_gettid));
-#endif
-
-		return;
-	}
-# ifdef TIMER_DEBUG
-	else fprintf(stderr, "timer %#jx set on thread %d (%ld seconds)\n", (uintmax_t) timer, (pid_t) syscall(SYS_gettid), seconds);
-# endif
+#elif defined(ZEND_TIMER)
+	zend_timer_settime(seconds);
 
 	if (reset_signals) {
 		sigset_t sigset;
@@ -1562,6 +1522,8 @@ void zend_unset_timeout(void) /* {{{ */
 		}
 		tq_timer = NULL;
 	}
+#elif ZEND_TIMER
+	zend_timer_settime(0);
 #elif defined(HAVE_SETITIMER)
 	if (EG(timeout_seconds)) {
 		struct itimerval no_timeout;

Zend/zend_globals.h

@@ -22,7 +22,7 @@
 
 
 #include <setjmp.h>
-#if defined(ZTS) && defined(HAVE_TIMER_CREATE)
+#ifdef ZEND_TIMER
 #include <time.h>
 #endif
 
@@ -269,7 +269,7 @@ struct _zend_executor_globals {
 	uint32_t num_errors;
 	zend_error_info **errors;
 
-#if defined(ZTS) && defined(HAVE_TIMER_CREATE)
+#ifndef ZEND_TIMER
 	timer_t timer;
 #endif
 

Zend/zend_timer.h

@@ -0,0 +1,18 @@
+#if !defined(ZEND_TIMER_H) && defined(ZTS) && defined(__linux__) && defined(HAVE_TIMER_CREATE)
+#define ZEND_TIMER_H
+
+#define ZEND_TIMER 1
+
+#include <signal.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+
+// Musl Libc defines this macro, glibc does not
+// According to "man 2 timer_create" this field should always be available, but it's not: https://sourceware.org/bugzilla/show_bug.cgi?id=27417
+# ifndef sigev_notify_thread_id
+# define sigev_notify_thread_id _sigev_un._tid
+# endif
+
+#endif