From 66f6055a133e6cbeee28b714d2bfbdefa769ccf8 Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Mon, 21 Nov 2011 14:57:02 +0100
Subject: [PATCH] Added cp(1).

---
 utils/Makefile |  1 +
 utils/cp.cpp   | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 utils/cp.cpp

diff --git a/utils/Makefile b/utils/Makefile
index daad2298..137ac265 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -6,6 +6,7 @@ INITRDDIR:=../initrd
 LOCALBINARIES:=\
 init \
 cat \
+cp \
 sh \
 mxsh \
 clear \
diff --git a/utils/cp.cpp b/utils/cp.cpp
new file mode 100644
index 00000000..a43002ba
--- /dev/null
+++ b/utils/cp.cpp
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+bool writeall(int fd, const void* buffer, size_t len)
+{
+	const char* buf = (const char*) buffer;
+	while ( len )
+	{
+		ssize_t byteswritten = write(fd, buf, len);
+		if ( byteswritten < 0 ) { return false; }
+		buf += byteswritten;
+		len -= byteswritten;
+	}
+
+	return true;
+}
+
+int main(int argc, char* argv[])
+{
+	if ( argc != 3 ) { printf("usage: %s <from> <to>\n", argv[0]); return 0; }
+
+	int fromfd = open(argv[1], O_RDONLY);
+	if ( fromfd < 0 ) { printf("%s: cannot open for reading: %s\n", argv[0], argv[1]); return 1; }
+
+	int tofd = open(argv[2], O_WRONLY | O_TRUNC | O_CREAT, 0777);
+	if ( tofd < 0 ) { printf("%s: cannot open for writing: %s\n", argv[0], argv[2]); return 1; }
+
+	while ( true )
+	{
+		const size_t BUFFER_SIZE = 4096;
+		char buffer[BUFFER_SIZE];
+		ssize_t bytesread = read(fromfd, buffer, BUFFER_SIZE);
+		if ( bytesread < 0 ) { printf("%s: read failed: %s\n", argv[0], argv[1]); return 1; }
+		if ( bytesread == 0 ) { return 0; }
+		if ( !writeall(tofd, buffer, bytesread) ) { printf("%s: write failed: %s\n", argv[0], argv[2]); return 1; }
+	}
+}