Snap for 7474514 from 6901182adc9a85d7f514df4d68605a179c195f75 to mainline-media-releaseandroid-mainline-12.0.0_r89android-mainline-12.0.0_r74android-mainline-12.0.0_r62android-mainline-12.0.0_r46android-mainline-12.0.0_r29android-mainline-12.0.0_r12android-mainline-12.0.0_r119android-mainline-12.0.0_r104android12-mainline-media-release

Change-Id: I1756a28b97a568bbb2c02438730597bb2aa59efe

1 files changed, 112 insertions, 0 deletions

diff --git a/brillo/files/file_util.cc b/brillo/files/file_util.cc
new file mode 100644
index 0000000..c642d14
--- /dev/null
+++ b/brillo/files/file_util.cc
@@ -0,0 +1,112 @@
+// Copyright 2019 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 "brillo/files/file_util.h"
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <utility>
+
+#include <base/files/file_util.h>
+#include <base/logging.h>
+#include <base/strings/stringprintf.h>
+#include <brillo/syslog_logging.h>
+
+namespace brillo {
+
+namespace {
+
+enum class FSObjectType {
+  RegularFile = 0,
+  Directory,
+};
+
+SafeFD::SafeFDResult OpenOrRemake(SafeFD* parent,
+                                  const std::string& name,
+                                  FSObjectType type,
+                                  int permissions,
+                                  uid_t uid,
+                                  gid_t gid,
+                                  int flags) {
+  SafeFD::Error err = IsValidFilename(name);
+  if (SafeFD::IsError(err)) {
+    return std::make_pair(SafeFD(), err);
+  }
+
+  SafeFD::SafeFDResult (SafeFD::*maker)(const base::FilePath&, mode_t, uid_t,
+                                        gid_t, int);
+  if (type == FSObjectType::Directory) {
+    maker = &SafeFD::MakeDir;
+  } else {
+    maker = &SafeFD::MakeFile;
+  }
+
+  SafeFD child;
+  std::tie(child, err) =
+      (parent->*maker)(base::FilePath(name), permissions, uid, gid, flags);
+  if (child.is_valid()) {
+    return std::make_pair(std::move(child), err);
+  }
+
+  // Rmdir should be used on directories. However, kWrongType indicates when
+  // a directory was expected and a non-directory was found or when a
+  // directory was found but not expected, so XOR was used.
+  if ((type == FSObjectType::Directory) ^ (err == SafeFD::Error::kWrongType)) {
+    err = parent->Rmdir(name, true /*recursive*/);
+  } else {
+    err = parent->Unlink(name);
+  }
+  if (SafeFD::IsError(err)) {
+    PLOG(ERROR) << "Failed to clean up \"" << name << "\"";
+    return std::make_pair(SafeFD(), err);
+  }
+
+  std::tie(child, err) =
+      (parent->*maker)(base::FilePath(name), permissions, uid, gid, flags);
+  return std::make_pair(std::move(child), err);
+}
+
+}  // namespace
+
+SafeFD::Error IsValidFilename(const std::string& filename) {
+  if (filename == "." || filename == ".." ||
+      filename.find("/") != std::string::npos) {
+    return SafeFD::Error::kBadArgument;
+  }
+  return SafeFD::Error::kNoError;
+}
+
+base::FilePath GetFDPath(int fd) {
+  const base::FilePath proc_fd(base::StringPrintf("/proc/self/fd/%d", fd));
+  base::FilePath resolved;
+  if (!base::ReadSymbolicLink(proc_fd, &resolved)) {
+    LOG(ERROR) << "Failed to read " << proc_fd.value();
+    return base::FilePath();
+  }
+  return resolved;
+}
+
+SafeFD::SafeFDResult OpenOrRemakeDir(SafeFD* parent,
+                                     const std::string& name,
+                                     int permissions,
+                                     uid_t uid,
+                                     gid_t gid,
+                                     int flags) {
+  return OpenOrRemake(parent, name, FSObjectType::Directory, permissions, uid,
+                      gid, flags);
+}
+
+SafeFD::SafeFDResult OpenOrRemakeFile(SafeFD* parent,
+                                      const std::string& name,
+                                      int permissions,
+                                      uid_t uid,
+                                      gid_t gid,
+                                      int flags) {
+  return OpenOrRemake(parent, name, FSObjectType::RegularFile, permissions, uid,
+                      gid, flags);
+}
+
+}  // namespace brillo