Check return code of fwrite in raw image writing code.

data_layout.c

Index: data_layout.c
diff --git a/data_layout.c b/data_layout.c
index 3c49f9f20b7d98b4b3277bd8f92726c4792bebf9..1e38b0ff6cd7cc835dd3c90e3710363ac98a0526 100644
--- a/data_layout.c
+++ b/data_layout.c
@@ -1017,9 +1017,12 @@ write_block_raw(build_image_context *context)
 			data = empty_blk;
 		}
 		/* Write the data */
-		fwrite(data, 1,
-			pages_to_write * context->page_size,
-			context->raw_file);
+		{

[Micah C, 2011/02/08 03:52:46]

What is the need for this extra indentation and enclosing braces?

[robotboy, 2011/02/08 18:48:00]

ANSI C doesn't allow for the declaration of a variable anywhere but at the
beginning of a block.  I did it this way because the bytes variable is not
needed anywhere outside this block and it localized the change.

+			size_t	bytes = pages_to_write * context->page_size;

[Micah C, 2011/02/08 03:52:46]

The \t after size_t bytes might be replaceable with a space to be consistent
with the rest of the file.

[robotboy, 2011/02/08 18:48:00]

Done.

+
+			if (fwrite(data, 1, bytes, context->raw_file) != bytes)
+				return -1;

[Micah C, 2011/02/08 03:52:46]

Another error exit from this function returns a negative symbolic constant
(-ENOMEM).  Is there an appropriately named error return value that fits this
path better than -1?  What does the caller of write_block_raw() expect?

[robotboy, 2011/02/08 18:48:00]

I believe that the correct thing to do is check both feof() and ferror() upon
seeing a smaller count than was requested to be written returned.  Then an
appropriate error code can be determined and returned.  In this case the caller
of write_block_raw is just checking that the return code is != 0 and if it is
(not equal to zero) then it prints a generic failure message.

+		}
 	}
 
 	free(empty_blk);