From 9215caf9c5965b2f12b0e6412a593ade94af748b Mon Sep 17 00:00:00 2001
From: Ben Harris <mail@benharris.ch>
Date: Thu, 29 Sep 2016 14:28:39 -0400
Subject: [PATCH] init

---
 mmapcp.cc | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 mmapcp.cc

diff --git a/mmapcp.cc b/mmapcp.cc
new file mode 100644
index 0000000..ce0e292
--- /dev/null
+++ b/mmapcp.cc
@@ -0,0 +1,44 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <string.h>
+#include <sys/stat.h>
+
+int main(int argc, char *argv[])
+{
+        int s, d;
+        struct stat st;
+        void *sp, *dp;
+        s = open(argv[1], O_RDONLY);
+        if (s == -1) {
+                perror("open source");
+                exit(1);
+        }
+        d = open(argv[2], O_RDWR | O_CREAT | O_TRUNC, 0644);
+        if (d == -1) {
+                perror("open destintation");
+                exit(1);
+        }
+        if (fstat(s, &st)) {
+                perror("stat source");
+                exit(1);
+        }
+        if (ftruncate(d, st.st_size)) {
+                perror("truncate destination");
+                exit(1);
+        }
+        sp = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, s, 0);
+        if (sp == MAP_FAILED) {
+                perror("map source");
+                exit(1);
+        }
+        dp = mmap(NULL, st.st_size, PROT_WRITE | PROT_READ, MAP_SHARED, d, 0);
+        if (dp == MAP_FAILED) {
+                perror("map destintation");
+                exit(1);
+        }
+        memcpy(dp, sp, st.st_size);
+        return 0;
+}