diff -urpN busybox-1.2.0/include/libbb.h busybox-1.2.0-cp/include/libbb.h
--- busybox-1.2.0/include/libbb.h	2006-07-01 00:42:10.000000000 +0200
+++ busybox-1.2.0-cp/include/libbb.h	2011-08-04 10:53:28.403950705 +0200
@@ -160,8 +160,8 @@ extern char *find_block_device(char *pat
 extern char *bb_get_line_from_file(FILE *file);
 extern char *bb_get_chomped_line_from_file(FILE *file);
 extern char *bb_get_chunk_from_file(FILE *file, int *end);
-extern int bb_copyfd_size(int fd1, int fd2, const off_t size);
-extern int bb_copyfd_eof(int fd1, int fd2);
+extern off_t bb_copyfd_size(int fd1, int fd2, off_t size);
+extern off_t bb_copyfd_eof(int fd1, int fd2);
 extern void  bb_xprint_and_close_file(FILE *file);
 extern int   bb_xprint_file_by_name(const char *filename);
 extern char  bb_process_escape_sequence(const char **ptr);
diff -urpN busybox-1.2.0/libbb/copyfd.c busybox-1.2.0-cp/libbb/copyfd.c
--- busybox-1.2.0/libbb/copyfd.c	2006-07-01 00:42:08.000000000 +0200
+++ busybox-1.2.0-cp/libbb/copyfd.c	2011-08-04 10:54:58.708818468 +0200
@@ -14,62 +14,66 @@
 
 #include "libbb.h"
 
-
-#if BUFSIZ < 4096
-#undef BUFSIZ
-#define BUFSIZ 4096
-#endif
-
-
-static ssize_t bb_full_fd_action(int src_fd, int dst_fd, size_t size)
+static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
 {
 	int status = -1;
-	size_t total = 0;
-	RESERVE_CONFIG_BUFFER(buffer,BUFSIZ);
+	off_t total = 0;
+	char buffer[4 * 1024];
+	enum { buffer_size = sizeof(buffer) };
+
+	if (src_fd < 0)
+		goto out;
+
+	if (!size) {
+		size = buffer_size;
+		status = 1; /* copy until eof */
+	}
+
+	while (1) {
+		ssize_t rd;
+
+		rd = safe_read(src_fd, buffer, size > buffer_size ? buffer_size : size);
 
-	if (src_fd < 0) goto out;
-	while (!size || total < size)
-	{
-		ssize_t wrote, xread;
-
-		xread = safe_read(src_fd, buffer,
-				(!size || size - total > BUFSIZ) ? BUFSIZ : size - total);
-
-		if (xread > 0) {
-			/* A -1 dst_fd means we need to fake it... */
-			wrote = (dst_fd < 0) ? xread : bb_full_write(dst_fd, buffer, xread);
-			if (wrote < xread) {
+		if (!rd) { /* eof - all done */
+			status = 0;
+			break;
+		}
+		if (rd < 0) {
+			bb_perror_msg(bb_msg_read_error);
+			break;
+		}
+		/* dst_fd == -1 is a fake, else... */
+		if (dst_fd >= 0) {
+			ssize_t wr = bb_full_write(dst_fd, buffer, rd);
+			if (wr < rd) {
 				bb_perror_msg(bb_msg_write_error);
 				break;
 			}
-			total += wrote;
-			if (total == size) status = 0;
-		} else if (xread < 0) {
-			bb_perror_msg(bb_msg_read_error);
-			break;
-		} else if (xread == 0) {
-			/* All done. */
-			status = 0;
-			break;
+		}
+		total += rd;
+		if (status < 0) { /* if we aren't copying till EOF... */
+			size -= rd;
+			if (!size) {
+				/* 'size' bytes copied - all done */
+				status = 0;
+				break;
+			}
 		}
 	}
+ out:
 
-out:
-	RELEASE_CONFIG_BUFFER(buffer);
-
-	return status ? status : (ssize_t)total;
+	return status ? -1 : total;
 }
 
-
-int bb_copyfd_size(int fd1, int fd2, const off_t size)
+off_t bb_copyfd_size(int fd1, int fd2, off_t size)
 {
 	if (size) {
-		return(bb_full_fd_action(fd1, fd2, size));
+		return bb_full_fd_action(fd1, fd2, size);
 	}
-	return(0);
+	return 0;
 }
 
-int bb_copyfd_eof(int fd1, int fd2)
+off_t bb_copyfd_eof(int fd1, int fd2)
 {
-	return(bb_full_fd_action(fd1, fd2, 0));
+	return bb_full_fd_action(fd1, fd2, 0);
 }