Index: src/platform/update_engine/extent_mapper.cc |
diff --git a/src/platform/update_engine/extent_mapper.cc b/src/platform/update_engine/extent_mapper.cc |
new file mode 100755 |
index 0000000000000000000000000000000000000000..9546cfbaebfb2e0931c9cf051fdfd1f48d45f5e4 |
--- /dev/null |
+++ b/src/platform/update_engine/extent_mapper.cc |
@@ -0,0 +1,79 @@ |
+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#include "update_engine/extent_mapper.h" |
+#include <sys/ioctl.h> |
+#include <sys/types.h> |
+#include <sys/stat.h> |
+#include <assert.h> |
+#include <errno.h> |
+#include <fcntl.h> |
+#include <stdio.h> |
+#include <string.h> |
+#include <linux/fs.h> |
+#include "update_engine/utils.h" |
+ |
+using std::string; |
+using std::vector; |
+ |
+namespace chromeos_update_engine { |
+ |
+namespace { |
+const int kBlockSize = 4096; |
+} |
+ |
+bool ExtentsForFileFibmap(const std::string& path, std::vector<Extent>* out) { |
+ CHECK(out); |
+ // TODO(adlr): verify path is a file |
+ struct stat stbuf; |
+ int rc = stat(path.c_str(), &stbuf); |
+ TEST_AND_RETURN_FALSE_ERRNO(rc == 0); |
+ TEST_AND_RETURN_FALSE(S_ISREG(stbuf.st_mode)); |
+ |
+ int fd = open(path.c_str(), O_RDONLY, 0); |
+ TEST_AND_RETURN_FALSE_ERRNO(fd >= 0); |
+ ScopedFdCloser fd_closer(&fd); |
+ |
+ // Get file size in blocks |
+ rc = fstat(fd, &stbuf); |
+ if (rc < 0) { |
+ perror("fstat"); |
+ return false; |
+ } |
+ const int block_count = (stbuf.st_size + kBlockSize - 1) / kBlockSize; |
+ Extent current; |
+ current.set_start_block(0); |
+ current.set_num_blocks(0); |
+ |
+ for (int i = 0; i < block_count; i++) { |
+ unsigned int block = i; |
+ rc = ioctl(fd, FIBMAP, &block); |
+ TEST_AND_RETURN_FALSE_ERRNO(rc == 0); |
+ |
+ // Add next block to extents |
+ if (current.num_blocks() == 0) { |
+ // We're starting a new extent |
+ current.set_start_block(block); |
+ current.set_num_blocks(1); |
+ continue; |
+ } |
+ if ((current.start_block() + current.num_blocks()) == block) { |
+ // We're continuing the last extent |
+ current.set_num_blocks(current.num_blocks() + 1); |
+ continue; |
+ } |
+ // We're starting a new extent and keeping the current one |
+ out->push_back(current); |
+ current.set_start_block(block); |
+ current.set_num_blocks(1); |
+ continue; |
+ } |
+ |
+ if (current.num_blocks() > 0) |
+ out->push_back(current); |
+ |
+ return true; |
+} |
+ |
+} // namespace chromeos_update_engine |