Use custom isc_mem based allocator for libuv

The libuv library provides a way to replace the default allocator with
user supplied allocator (malloc, realloc, calloc and free).

Create a memory context specifically for libuv to allow tracking the
memory usage that has originated from within libuv.  This requires
libuv >= 1.38.0 which provides uv_library_shutdown() function that
assures no more allocations will be made.

lib/isc/include/isc/uv.h

@@ -107,3 +107,14 @@ isc__uverr2result(int uverr, bool dolog, const char *file, unsigned int line,
 	})
 
 #endif
+
+/*
+ * Internal
+ */
+
+void
+isc__uv_initialize(void);
+void
+isc__uv_shutdown(void);
+void
+isc__uv_setdestroycheck(bool check);

lib/isc/lib.c

@@ -18,6 +18,7 @@
 #include <isc/os.h>
 #include <isc/tls.h>
 #include <isc/util.h>
+#include <isc/uv.h>
 
 #include "config.h"
 #include "mem_p.h"
@@ -46,11 +47,13 @@ isc__initialize(void) {
 	isc__mem_initialize();
 	isc__tls_initialize();
 	isc__trampoline_initialize();
+	isc__uv_initialize();
 	(void)isc_os_ncpus();
 }
 
 void
 isc__shutdown(void) {
+	isc__uv_shutdown();
 	isc__trampoline_shutdown();
 	isc__tls_shutdown();
 	isc__mem_shutdown();

lib/isc/uv.c

@@ -13,6 +13,7 @@
 
 #include <unistd.h>
 
+#include <isc/mem.h>
 #include <isc/util.h>
 #include <isc/uv.h>
 
@@ -97,3 +98,74 @@ isc__uverr2result(int uverr, bool dolog, const char *file, unsigned int line,
 		return (ISC_R_UNEXPECTED);
 	}
 }
+
+#if UV_VERSION_HEX >= UV_VERSION(1, 38, 0)
+static isc_mem_t *isc__uv_mctx = NULL;
+
+static void *
+isc__uv_malloc(size_t size) {
+	return (isc_mem_allocate(isc__uv_mctx, size));
+}
+
+static void *
+isc__uv_realloc(void *ptr, size_t size) {
+	return (isc_mem_reallocate(isc__uv_mctx, ptr, size));
+}
+
+static void *
+isc__uv_calloc(size_t count, size_t size) {
+	void *ptr;
+	size_t res;
+#if HAVE_BUILTIN_MUL_OVERFLOW
+	bool overflow = __builtin_mul_overflow(count, size, &res);
+	RUNTIME_CHECK(!overflow);
+#else
+	res = count * size;
+	REQUIRE(count == 0 || res / count == size);
+#endif
+
+	ptr = isc_mem_allocate(isc__uv_mctx, res);
+	memset(ptr, 0, res);
+
+	return (ptr);
+}
+
+static void
+isc__uv_free(void *ptr) {
+	if (ptr == NULL) {
+		return;
+	}
+	isc_mem_free(isc__uv_mctx, ptr);
+}
+#endif /* UV_VERSION_HEX >= UV_VERSION(1, 38, 0) */
+
+void
+isc__uv_initialize(void) {
+#if UV_VERSION_HEX >= UV_VERSION(1, 38, 0)
+	int r;
+	isc_mem_create(&isc__uv_mctx);
+	isc_mem_setname(isc__uv_mctx, "uv");
+	isc_mem_setdestroycheck(isc__uv_mctx, false);
+
+	r = uv_replace_allocator(isc__uv_malloc, isc__uv_realloc,
+				 isc__uv_calloc, isc__uv_free);
+	UV_RUNTIME_CHECK(uv_replace_allocator, r);
+#endif /* UV_VERSION_HEX >= UV_VERSION(1, 38, 0) */
+}
+
+void
+isc__uv_shutdown(void) {
+#if UV_VERSION_HEX >= UV_VERSION(1, 38, 0)
+	uv_library_shutdown();
+	isc_mem_destroy(&isc__uv_mctx);
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 38, 0) */
+}
+
+void
+isc__uv_setdestroycheck(bool check) {
+#if UV_VERSION_HEX >= UV_VERSION(1, 38, 0)
+	isc_mem_setdestroycheck(isc__uv_mctx, check);
+#else
+	UNUSED(check);
+#endif /* UV_VERSION_HEX >= UV_VERSION(1, 6, 0) */
+}