libc_compat: Utilize #include_next to avoid contrib patching

2 files changed, 59 insertions, 0 deletions

diff --git a/contrib/libs/libc_compat/reallocarray/reallocarray.c b/contrib/libs/libc_compat/reallocarray/reallocarray.c
new file mode 100644
index 0000000000..21b0914fe4
--- /dev/null
+++ b/contrib/libs/libc_compat/reallocarray/reallocarray.c
@@ -0,0 +1,39 @@
+/*	$OpenBSD: reallocarray.c,v 1.3 2015/09/13 08:31:47 guenther Exp $	*/
+/*
+ * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+/*
+ * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
+ * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
+ */
+#define MUL_NO_OVERFLOW	((size_t)1 << (sizeof(size_t) * 4))
+
+void *
+reallocarray(void *optr, size_t nmemb, size_t size)
+{
+	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
+	    nmemb > 0 && SIZE_MAX / nmemb < size) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	return realloc(optr, size * nmemb);
+}
+
diff --git a/contrib/libs/libc_compat/reallocarray/stdlib.h b/contrib/libs/libc_compat/reallocarray/stdlib.h
new file mode 100644
index 0000000000..4b27573a37
--- /dev/null
+++ b/contrib/libs/libc_compat/reallocarray/stdlib.h
@@ -0,0 +1,20 @@
+// The lack of #pragma once is intentional:
+// its presence breaks compilation of contrib/tools/unbound somehow.
+
+#if defined(__GNUC__) || defined(__clang__)
+    #include_next <stdlib.h>
+#else
+    #define Y_MSVC_INCLUDE_NEXT(x) <Y_UCRT_INCLUDE/x>
+    #include Y_MSVC_INCLUDE_NEXT(stdlib.h)
+    #undef Y_MSVC_INCLUDE_NEXT
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void* reallocarray(void*, size_t, size_t);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif