Changes in uspace/lib/block/libblock.c [c7bbf029:c4aa9cf] in mainline

File:

• uspace/lib/block/libblock.c (modified) (2 diffs)

uspace/lib/block/libblock.c

@@ -2 +2 @@
  * Copyright (c) 2008 Jakub Jermar
  * Copyright (c) 2008 Martin Decky
+ * Copyright (c) 2011 Martin Sucha
  * All rights reserved.
  *
@@ -827 +828 @@
 }
 
+/** Read bytes directly from the device (bypass cache)
+ * 
+ * @param devmap_handle Device handle of the block device.
+ * @param abs_offset    Absolute offset in bytes where to start reading
+ * @param bytes                 Number of bytes to read
+ * @param data                  Buffer that receives the data
+ * 
+ * @return              EOK on success or negative error code on failure.
+ */
+int block_read_bytes_direct(devmap_handle_t devmap_handle, aoff64_t abs_offset,
+    size_t bytes, void *data)
+{
+        int rc;
+        size_t phys_block_size;
+        size_t buf_size;
+        void *buffer;
+        aoff64_t first_block;
+        aoff64_t last_block;
+        size_t blocks;
+        size_t offset;
+        
+        rc = block_get_bsize(devmap_handle, &phys_block_size);
+        if (rc != EOK) {
+                return rc;
+        }
+        
+        /* calculate data position and required space */
+        first_block = abs_offset / phys_block_size;
+        offset = abs_offset % phys_block_size;
+        last_block = (abs_offset + bytes - 1) / phys_block_size;
+        blocks = last_block - first_block + 1;
+        buf_size = blocks * phys_block_size;
+        
+        /* read the data into memory */
+        buffer = malloc(buf_size);
+        if (buffer == NULL) {
+                return ENOMEM;
+        }
+        
+        rc = block_read_direct(devmap_handle, first_block, blocks, buffer);
+        if (rc != EOK) {
+                free(buffer);
+                return rc;
+        }
+        
+        /* copy the data from the buffer */
+        memcpy(data, buffer + offset, bytes);
+        free(buffer);
+        
+        return EOK;
+}
+
 /** Read blocks from block device.
  *