From 2809fd3795e8445f686547d08eef4631efc05030 Mon Sep 17 00:00:00 2001
From: sin <sin@2f30.org>
Date: Wed, 6 Jan 2016 17:02:28 +0000
Subject: [PATCH] Bring in reallocarray() from OpenBSD

---
 Makefile       |  1 +
 compat.h       |  2 ++
 config.mk      |  4 ++--
 reallocarray.c | 39 +++++++++++++++++++++++++++++++++++++++
 strlcat.c      |  2 ++
 strlcpy.c      |  2 ++
 6 files changed, 48 insertions(+), 2 deletions(-)
 create mode 100644 reallocarray.c

diff --git a/Makefile b/Makefile
index eff0f5a..7d6454a 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,7 @@ SRC = \
 	stagit.c\
 	stagit-index.c
 COMPATSRC = \
+	reallocarray.c\
 	strlcat.c\
 	strlcpy.c
 BIN = \
diff --git a/compat.h b/compat.h
index 0947de6..f619c16 100644
--- a/compat.h
+++ b/compat.h
@@ -3,4 +3,6 @@
 size_t strlcat(char *, const char *, size_t);
 #undef strlcpy
 size_t strlcpy(char *, const char *, size_t);
+#undef reallocarray
+void *reallocarray(void *, size_t, size_t);
 #endif
diff --git a/config.mk b/config.mk
index 934db3b..6e84946 100644
--- a/config.mk
+++ b/config.mk
@@ -28,8 +28,8 @@ LDFLAGS = ${LIBS}
 
 # uncomment for compat
 CFLAGS += -DCOMPAT
-# uncomment if your libc doesn't support strlcat, strlcpy.
-COMPATOBJ = strlcat.o strlcpy.o
+# uncomment if your libc doesn't support reallocarray, strlcat, strlcpy.
+COMPATOBJ = reallocarray.o strlcat.o strlcpy.o
 
 # compiler and linker
 #CC = cc
diff --git a/reallocarray.c b/reallocarray.c
new file mode 100644
index 0000000..b92dae5
--- /dev/null
+++ b/reallocarray.c
@@ -0,0 +1,39 @@
+/*
+ * 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>
+
+#include "compat.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	(1UL << (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/strlcat.c b/strlcat.c
index 14c53a1..bbfa64f 100644
--- a/strlcat.c
+++ b/strlcat.c
@@ -19,6 +19,8 @@
 #include <sys/types.h>
 #include <string.h>
 
+#include "compat.h"
+
 /*
  * Appends src to string dst of size dsize (unlike strncat, dsize is the
  * full size of dst, not space left).  At most dsize-1 characters
diff --git a/strlcpy.c b/strlcpy.c
index e9a7fe4..ab420b6 100644
--- a/strlcpy.c
+++ b/strlcpy.c
@@ -19,6 +19,8 @@
 #include <sys/types.h>
 #include <string.h>
 
+#include "compat.h"
+
 /*
  * Copy string src to buffer dst of size dsize.  At most dsize-1
  * chars will be copied.  Always NUL terminates (unless dsize == 0).
-- 
2.39.2