[PATCH 2/3] libfile: Add copy_fd()

[Sascha Hauer]

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 include/libfile.h |  1 +
 lib/libfile.c     | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/libfile.h b/include/libfile.h
index 350ddddf70..3c2fe1714d 100644
--- a/include/libfile.h
+++ b/include/libfile.h
@@ -5,6 +5,7 @@
 int pwrite_full(int fd, const void *buf, size_t size, loff_t offset);
 int write_full(int fd, const void *buf, size_t size);
 int read_full(int fd, void *buf, size_t size);
+int copy_fd(int in, int out);
 
 char *read_file_line(const char *fmt, ...);
 
diff --git a/lib/libfile.c b/lib/libfile.c
index 4ab8db11ad..e42126017d 100644
--- a/lib/libfile.c
+++ b/lib/libfile.c
@@ -100,6 +100,40 @@ int read_full(int fd, void *buf, size_t size)
 }
 EXPORT_SYMBOL(read_full);
 
+int copy_fd(int in, int out)
+{
+	int bs = 4096, ret;
+	void *buf = malloc(bs);
+
+	if (!buf)
+		return -ENOMEM;
+
+	while (1) {
+		int now, wr;
+
+		now = read(in, buf, bs);
+		if (now < 0) {
+			ret = now;
+			goto err;
+		}
+
+		if (!now)
+			break;
+
+		wr = write_full(out, buf, now);
+		if (wr < 0) {
+			ret = wr;
+			goto err;
+		}
+	}
+
+	ret = 0;
+err:
+        free(buf);
+
+	return ret;
+}
+
 /*
  * read_file_line - read a line from a file
  *
-- 
2.29.2