commit 9f21d7d47a8af692ccf19714ca59af873003434a
author Pavol Marko <pmarko@chromium.org> Fri Jun 30 14:41:55 2017
committer chrome-bot <chrome-bot@chromium.org> Mon Jul 17 17:28:24 2017
tree a31f8490683d151d2f8d5e745f0e579a24998605
parent 070af5efe6be713dc10310405c3951939fda828a

libbrillo: Add GetDaemonPathForTemporaryUserHome to cryptohome utilities

Similar to GetDaemonPath, GetDaemonPathForTemporaryUserHome returns
the directory where the passed daemon should store its data for a
temporary user home mount.

BUG=chromium:722371
TEST=Tests still pass, actual functionality tested by CL
https://chromium-review.googlesource.com/c/562158/

Change-Id: I06efeed13bc611bab9baa542de47d9f7112e792e
Reviewed-on: https://chromium-review.googlesource.com/562277
Commit-Ready: Pavol Marko <pmarko@chromium.org>
Tested-by: Pavol Marko <pmarko@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>

brillo/cryptohome.cc

diff --git a/brillo/cryptohome.cc b/brillo/cryptohome.cc
index 49a4a88..88e4739 100644
--- a/brillo/cryptohome.cc
+++ b/brillo/cryptohome.cc
@@ -24,6 +24,17 @@
 
 const char kGuestUserName[] = "$guest";
 
+// Path to user homes mounted with the mount_hidden option. The user home mount
+// will be located at:
+// kHiddenUserHomeBaseDir/<sanitized_user_name>/kHiddenUserHomeMountSubdir
+const char kHiddenUserHomeBaseDir[] = "/home/.shadow";
+const char kHiddenUserHomeMountSubdir[] = "mount";
+
+// Subdirectory of a user home mount where daemon-specific data is stored.
+// This is used to assemble daemon data storage paths for hidden user home
+// mounts.
+const char kHiddenUserHomeRootSubdir[] = "root";
+
 static char g_user_home_prefix[PATH_MAX] = "/home/user/";
 static char g_root_home_prefix[PATH_MAX] = "/home/root/";
 static char g_system_salt_path[PATH_MAX] = "/home/.shadow/salt";
@@ -92,23 +103,35 @@
 
 FilePath GetUserPath(const std::string& username) {
   if (!EnsureSystemSaltIsLoaded())
-    return FilePath("");
+    return FilePath();
   return GetHashedUserPath(SanitizeUserName(username));
 }
 
 FilePath GetRootPath(const std::string& username) {
   if (!EnsureSystemSaltIsLoaded())
-    return FilePath("");
+    return FilePath();
   return FilePath(base::StringPrintf(
       "%s%s", g_root_home_prefix, SanitizeUserName(username).c_str()));
 }
 
 FilePath GetDaemonPath(const std::string& username, const std::string& daemon) {
   if (!EnsureSystemSaltIsLoaded())
-    return FilePath("");
+    return FilePath();
   return GetRootPath(username).Append(daemon);
 }
 
+FilePath GetDaemonPathForHiddenUserHome(const std::string& username,
+                                        const std::string& daemon) {
+  if (!EnsureSystemSaltIsLoaded())
+    return FilePath();
+
+  return FilePath(kHiddenUserHomeBaseDir)
+      .Append(SanitizeUserName(username))
+      .Append(kHiddenUserHomeMountSubdir)
+      .Append(kHiddenUserHomeRootSubdir)
+      .Append(daemon);
+}
+
 bool IsSanitizedUserName(const std::string& sanitized) {
   std::vector<uint8_t> bytes;
   return (sanitized.length() == 2 * SHA_DIGEST_LENGTH) &&

brillo/cryptohome.h

diff --git a/brillo/cryptohome.h b/brillo/cryptohome.h
index caca31b..798d3a0 100644
--- a/brillo/cryptohome.h
+++ b/brillo/cryptohome.h
@@ -42,6 +42,12 @@
 BRILLO_EXPORT base::FilePath GetDaemonPath(const std::string& username,
                                            const std::string& daemon);
 
+// Returns the path at which the daemon |daemon| should store per-user data
+// when the user's home was mounted with mount_hidden.
+BRILLO_EXPORT base::FilePath GetDaemonPathForHiddenUserHome(
+    const std::string& username,
+    const std::string& daemon);
+
 // Checks whether |sanitized| has the format of a sanitized username.
 BRILLO_EXPORT bool IsSanitizedUserName(const std::string& sanitized);