Fix Zend signals unblocking

There are a few parts here:
 * opcache should not be blocking signals while invoking compile_file,
   otherwise signals may remain blocked on a compile error. While at
   it, also protect SHM memory during compile_file.
 * We should deactivate Zend signals at the end of the request, to make
   sure that we gracefully recover from a missing unblock and signals
   don't remain blocked forever.
 * We don't use a critical section in deactivation, because it should
   not be necessary. Additionally we want to clean up the signal queue,
   if it is non-empty.
 * Enable SIGG(check) in debug builds so we notice issues in the future.

diff --git a/Zend/zend_signal.c b/Zend/zend_signal.c
index 1cfab63eeeaf15f79943121eb5e160a16e31b119..f43de50b641ebeb59a56edeb33de3aae22d875f5 100644 (file)
--- a/Zend/zend_signal.c
+++ b/Zend/zend_signal.c
@@ -330,13 +330,13 @@ void zend_signal_activate(void)
 
        SIGG(active) = 1;
        SIGG(depth)  = 0;
+       SIGG(check)  = ZEND_DEBUG;
 } /* }}} */
 
 /* {{{ zend_signal_deactivate
  * */
 void zend_signal_deactivate(void)
 {
-
        if (SIGG(check)) {
                size_t x;
                struct sigaction sa;
@@ -344,21 +344,32 @@ void zend_signal_deactivate(void)
                if (SIGG(depth) != 0) {
                        zend_error(E_CORE_WARNING, "zend_signal: shutdown with non-zero blocking depth (%d)", SIGG(depth));
                }
+
                /* did anyone steal our installed handler */
                for (x = 0; x < sizeof(zend_sigs) / sizeof(*zend_sigs); x++) {
                        sigaction(zend_sigs[x], NULL, &sa);
-                       if (sa.sa_sigaction != zend_signal_handler_defer) {
+                       if (sa.sa_sigaction != zend_signal_handler_defer &&
+                                       sa.sa_sigaction != (void *) SIG_IGN) {
                                zend_error(E_CORE_WARNING, "zend_signal: handler was replaced for signal (%d) after startup", zend_sigs[x]);
                        }
                }
        }
 
-       SIGNAL_BEGIN_CRITICAL();
-       SIGG(active) = 0;
+       /* After active=0 is set, signal handlers will be called directly and other
+        * state that is reset below will not be accessed. */
+       *((volatile int *) &SIGG(active)) = 0;
+
        SIGG(running) = 0;
        SIGG(blocked) = 0;
        SIGG(depth) = 0;
-       SIGNAL_END_CRITICAL();
+
+       /* If there are any queued signals because of a missed unblock, drop them. */
+       if (SIGG(phead) && SIGG(ptail)) {
+               SIGG(ptail)->next = SIGG(pavail);
+               SIGG(pavail) = SIGG(phead);
+               SIGG(phead) = NULL;
+               SIGG(ptail) = NULL;
+       }
 }
 /* }}} */
 

diff --git a/ext/opcache/ZendAccelerator.c b/ext/opcache/ZendAccelerator.c
index 15629224244884402bba12f2a6e25c3b903ed87d..58016ce191045c0c1f850dd56944e479834bbd5f 100644 (file)
--- a/ext/opcache/ZendAccelerator.c
+++ b/ext/opcache/ZendAccelerator.c
@@ -1570,7 +1570,9 @@ static zend_persistent_script *opcache_compile_file(zend_file_handle *file_handl
 
        /* check blacklist right after ensuring that file was opened */
        if (file_handle->opened_path && zend_accel_blacklist_is_blacklisted(&accel_blacklist, ZSTR_VAL(file_handle->opened_path))) {
+               SHM_UNPROTECT();
                ZCSG(blacklist_misses)++;
+               SHM_PROTECT();
                *op_array_p = accelerator_orig_compile_file(file_handle, type);
                return NULL;
        }
@@ -1601,7 +1603,9 @@ static zend_persistent_script *opcache_compile_file(zend_file_handle *file_handl
                }
 
                if (ZCG(accel_directives).max_file_size > 0 && size > (size_t)ZCG(accel_directives).max_file_size) {
+                       SHM_UNPROTECT();
                        ZCSG(blacklist_misses)++;
+                       SHM_PROTECT();
                        *op_array_p = accelerator_orig_compile_file(file_handle, type);
                        return NULL;
                }
@@ -2003,11 +2007,16 @@ zend_op_array *persistent_compile_file(zend_file_handle *file_handle, int type)
                        return accelerator_orig_compile_file(file_handle, type);
                }
 
+               SHM_PROTECT();
+               HANDLE_UNBLOCK_INTERRUPTIONS();
+               persistent_script = opcache_compile_file(file_handle, type, key, &op_array);
+               HANDLE_BLOCK_INTERRUPTIONS();
+               SHM_UNPROTECT();
+
                /* Try and cache the script and assume that it is returned from_shared_memory.
          * If it isn't compile_and_cache_file() changes the flag to 0
          */
                from_shared_memory = 0;
-               persistent_script = opcache_compile_file(file_handle, type, key, &op_array);
                if (persistent_script) {
                        persistent_script = cache_script_in_shared_memory(persistent_script, key, key ? key_length : 0, &from_shared_memory);
                }

diff --git a/main/main.c b/main/main.c
index d68cb6eca4660ac02e3485164dc64b90a1a90cdc..37d520ec34b3619eec3a235f4dbf3a2671c22089 100644 (file)
--- a/main/main.c
+++ b/main/main.c
@@ -1932,6 +1932,11 @@ void php_request_shutdown(void *dummy)
                zend_unset_timeout();
        } zend_end_try();
 
+       /* 17. Deactivate Zend signals */
+#ifdef ZEND_SIGNALS
+       zend_signal_deactivate();
+#endif
+
 #ifdef PHP_WIN32
        if (PG(com_initialized)) {
                CoUninitialize();