From c4a294e498cd456c5421b3ffebdd64b1e15a062d Mon Sep 17 00:00:00 2001
From: Jakob Kaivo <jkk@ung.org>
Date: Tue, 30 Jun 2020 13:52:48 -0400
Subject: add wrapper library to LD_PRELOAD malloc(), calloc(), realloc(), and
 free()

---
 Makefile   | 13 +++++++++++--
 src/wrap.c | 21 +++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 src/wrap.c

diff --git a/Makefile b/Makefile
index 3f7db7f..867b86c 100644
--- a/Makefile
+++ b/Makefile
@@ -6,9 +6,10 @@ OBJDIR=obj
 SRCDIR=src
 INCDIR=include
 TESTDIR=test
-CFLAGS=-I$(INCDIR) -Wall -Wextra -Wpedantic -g
+CFLAGS=-I$(INCDIR) -Wall -Wextra -Wpedantic -g -fPIC
 
 OBJECTS=$(OBJDIR)/mapalloc.o
+WRAPOBJECTS=$(OBJECTS) $(OBJDIR)/wrap.o
 TESTS=$(BINDIR)/overflow \
 	$(BINDIR)/underflow \
 	$(BINDIR)/zero \
@@ -16,7 +17,7 @@ TESTS=$(BINDIR)/overflow \
 	$(BINDIR)/use-after-free \
 	$(BINDIR)/double-free
 
-all: $(LIBDIR)/libmapalloc.a 
+all: $(LIBDIR)/libmapalloc.a $(LIBDIR)/libwrapalloc.so
 
 #$(LIBDIR)/libmapalloc.so
 
@@ -26,6 +27,10 @@ $(OBJDIR)/mapalloc.o: $(SRCDIR)/mapalloc.c $(INCDIR)/mapalloc.h
 	@mkdir -p $(@D)
 	$(CC) -c -o $@ $(CFLAGS) $(SRCDIR)/$(*F).c
 
+$(OBJDIR)/wrap.o: $(SRCDIR)/wrap.c $(INCDIR)/mapalloc.h
+	@mkdir -p $(@D)
+	$(CC) -c -o $@ $(CFLAGS) $(SRCDIR)/$(*F).c
+
 $(LIBDIR)/libmapalloc.a: $(OBJECTS)
 	@mkdir -p $(@D)
 	$(AR) $(ARFLAGS) $@ $<
@@ -34,6 +39,10 @@ $(LIBDIR)/libmapalloc.so: $(OBJECTS)
 	@mkdir -p $(@D)
 	$(CC) -o $@ -shared $(OBJECTS)
 
+$(LIBDIR)/libwrapalloc.so: $(WRAPOBJECTS)
+	@mkdir -p $(@D)
+	$(CC) -o $@ -shared $(WRAPOBJECTS)
+
 $(TESTS): $(LIBDIR)/libmapalloc.a
 $(BINDIR)/overflow: $(TESTDIR)/overflow.c
 $(BINDIR)/underflow: $(TESTDIR)/underflow.c
diff --git a/src/wrap.c b/src/wrap.c
new file mode 100644
index 0000000..524d6d2
--- /dev/null
+++ b/src/wrap.c
@@ -0,0 +1,21 @@
+#include "mapalloc.h"
+
+void *malloc(size_t n)
+{
+	return map_malloc(n);
+}
+
+void *calloc(size_t n, size_t e)
+{
+	return map_calloc(n, e);
+}
+
+void *realloc(void *p, size_t n)
+{
+	return map_realloc(p, n);
+}
+
+void free(void *p)
+{
+	map_free(p);
+}
-- 
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