1 files changed, 59 insertions, 0 deletions
diff --git a/sapi/phpdbg/phpdbg_sigsafe.c b/sapi/phpdbg/phpdbg_sigsafe.c
new file mode 100644
index 0000000000..54af08ec5b
--- /dev/null
+++ b/sapi/phpdbg/phpdbg_sigsafe.c
@@ -0,0 +1,59 @@
+#include "phpdbg_sigsafe.h"
+#include "phpdbg.h"
+
+ZEND_EXTERN_MODULE_GLOBALS(phpdbg);
+
+#define STR(x) #x
+#define EXP_STR(x) STR(x)
+
+static void* zend_mm_mem_alloc(zend_mm_storage *storage, size_t size, size_t alignment) {
+
+	if (EXPECTED(size <= PHPDBG_SIGSAFE_MEM_SIZE && !PHPDBG_G(sigsafe_mem).allocated)) {
+		PHPDBG_G(sigsafe_mem).allocated = 1;
+		return (void *) (((size_t) PHPDBG_G(sigsafe_mem).mem & ~(alignment - 1)) + alignment);
+	}
+
+	quiet_write(PHPDBG_G(io)[PHPDBG_STDERR].fd, ZEND_STRL("Tried to allocate more than " EXP_STR(PHPDBG_SIGSAFE_MEM_SIZE) " bytes from stack memory in signal handler ... bailing out of signal handler\n"));
+
+	if (*EG(bailout)) {
+		LONGJMP(*EG(bailout), FAILURE);
+	}
+
+	quiet_write(PHPDBG_G(io)[PHPDBG_STDERR].fd, ZEND_STRL("Bailed out without a bailout address in signal handler!\n"));
+
+	return NULL;
+}
+
+static void zend_mm_mem_free(zend_mm_storage *storage, void *ptr, size_t size) {
+}
+
+void phpdbg_set_sigsafe_mem(char *buffer) {
+	phpdbg_signal_safe_mem *mem = &PHPDBG_G(sigsafe_mem);
+	const zend_mm_handlers phpdbg_handlers = {
+		zend_mm_mem_alloc,
+		zend_mm_mem_free,
+		NULL,
+		NULL,
+	};
+
+	mem->mem = buffer;
+	mem->allocated = 0;
+
+	mem->heap = zend_mm_startup_ex(&phpdbg_handlers, NULL, 0);
+
+	mem->old_heap = zend_mm_set_heap(mem->heap);
+}
+
+zend_mm_heap *phpdbg_original_heap_sigsafe_mem(void) {
+	return PHPDBG_G(sigsafe_mem).old_heap;
+}
+
+void phpdbg_clear_sigsafe_mem(void) {
+	zend_mm_set_heap(phpdbg_original_heap_sigsafe_mem());
+	PHPDBG_G(sigsafe_mem).mem = NULL;
+}
+
+zend_bool phpdbg_active_sigsafe_mem(void) {
+	return !!PHPDBG_G(sigsafe_mem).mem;
+}
+