vboot2: Add host library functions to read/write files and objects

And unit tests for them.

Move roundup32() into hostlib.

Fix WriteFile() returning success even if it failed to write to the file.

BUG=chromium:423882
BRANCH=none
TEST=VBOOT2=1 make runtests

Change-Id: I8a115335c088dc5c66c88423d1ccbda7eaca1996
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/230844

host/lib/include/host_misc.h

@@ -43,4 +43,45 @@ int ReadFileBit(const char* filename, int bitmask);
  * Returns 0 if success, 1 if error. */
 int WriteFile(const char* filename, const void *data, uint64_t size);
 
+/**
+ * Read data from a file into a newly allocated buffer.
+ *
+ * @param filename	Name of file to read from
+ * @param data_ptr	On exit, pointer to newly allocated buffer with data
+ *			will be stored here.  Caller must free() the buffer
+ *			when done with it.
+ * @param size_ptr	On exit, size of data will be stored here.
+ * @return VB2_SUCCESS, or non-zero if error.
+ */
+int vb2_read_file(const char *filename, uint8_t **data_ptr, uint32_t *size_ptr);
+
+/**
+ * Write data to a file from a buffer.
+ *
+ * @param filename	Name of file to write to
+ * @param buf		Buffer to write
+ * @param size		Number of bytes of data to write
+ * @return VB2_SUCCESS, or non-zero if error.
+ */
+int vb2_write_file(const char *filename, const void *buf, uint32_t size);
+
+/**
+ * Write a buffer which starts with a standard vb2_struct_common header.
+ *
+ * Determines the buffer size from the common header total size field.
+ *
+ * @param filename	Name of file to write to
+ * @param buf		Buffer to write
+ * @return VB2_SUCCESS, or non-zero if error.
+ */
+int vb2_write_object(const char *filename, const void *buf);
+
+/**
+ * Round up a size to a multiple of 32 bits (4 bytes).
+ */
+static __inline const uint32_t roundup32(uint32_t v)
+{
+	return (v + 3) & ~3;
+}
+
 #endif  /* VBOOT_REFERENCE_HOST_MISC_H_ */