1 files changed, 100 insertions, 0 deletions
diff --git a/print_status_on_exit.c b/print_status_on_exit.c
new file mode 100644
index 0000000..686817e
--- /dev/null
+++ b/print_status_on_exit.c
@@ -0,0 +1,100 @@
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+char tmpbuff[1024];
+unsigned long tmppos = 0;
+unsigned long tmpallocs = 0;
+
+/*=========================================================
+ *  * interception points
+ *  */
+
+static void * (*myfn_malloc)(size_t size);
+static void   (*myfn_free)(void *ptr);
+
+static void print_status(void)
+{
+	char buf[4096];
+
+	FILE* status = fopen("/proc/self/status", "r");
+	if (status == NULL)
+	{
+		perror("fopen status");
+		exit(1);
+	}
+
+	FILE* output = fopen("status", "w");
+	if (output == NULL)
+	{
+		perror("fopen output file");
+		exit(1);
+	}
+
+	while (!feof(status))
+	{
+		fgets(&buf, 4096, status);
+		fprintf(output, "%s", buf);
+	}
+	fclose(status);
+}
+
+static void init()
+{
+	myfn_malloc     = dlsym(RTLD_NEXT, "malloc");
+	myfn_free       = dlsym(RTLD_NEXT, "free");
+
+	if (!myfn_malloc || !myfn_free)
+	{
+		fprintf(stderr, "Error in `dlsym`: %s\n", dlerror());
+		exit(1);
+	}
+	atexit(print_status);
+}
+
+void *malloc(size_t size)
+{
+	static int initializing = 0;
+	if (myfn_malloc == NULL)
+	{
+		if (!initializing)
+		{
+			initializing = 1;
+			init();
+			initializing = 0;
+
+			fprintf(stdout, "jcheck: allocated %lu bytes of temp memory in %lu chunks during initialization\n", tmppos, tmpallocs);
+		}
+		else
+		{
+			if (tmppos + size < sizeof(tmpbuff))
+			{
+				void *retptr = tmpbuff + tmppos;
+				tmppos += size;
+				++tmpallocs;
+				return retptr;
+			}
+			else
+			{
+				fprintf(stdout, "jcheck: too much memory requested during initialisation - increase tmpbuff size\n");
+				exit(1);
+			}
+		}
+	}
+
+	return myfn_malloc(size);
+}
+
+void free(void *ptr)
+{
+	// something wrong if we call free before one of the allocators!
+	if (myfn_malloc == NULL)
+		init();
+	if (ptr >= (void*) tmpbuff && ptr <= (void*)(tmpbuff + tmppos))
+		fprintf(stdout, "freeing temp memory\n");
+	else
+		myfn_free(ptr);
+}
+