Document restricted app private file permissions

Make the docs reflect changes in private file access permissions.

Starting with API level 24 app private files are exclusively accessible
to the owning app. Files can no longer be shared by name because apps
cannot relax the files system permissions.

Bug: 27636012
Change-Id: Ibcb5032986c819829fa13ba07a74f20f2997e995

diff --git a/docs/html/guide/topics/data/data-storage.jd b/docs/html/guide/topics/data/data-storage.jd
index 46db371..0d3bb4d 100644 (file)
--- a/docs/html/guide/topics/data/data-storage.jd
+++ b/docs/html/guide/topics/data/data-storage.jd
@@ -178,6 +178,19 @@ android.content.Context#MODE_APPEND}, {@link
 android.content.Context#MODE_WORLD_READABLE}, and {@link
 android.content.Context#MODE_WORLD_WRITEABLE}.</p>
 
+<p class="note"><strong>Note:</strong> The constants {@link
+android.content.Context#MODE_WORLD_READABLE} and {@link
+android.content.Context#MODE_WORLD_WRITEABLE} have been deprecated since API level 17. Since
+API level 24 their use will result in a {@link java.lang.SecurityException} to be thrown.
+This means that apps targeting API level 24 and higher
+cannot share private files by name, and attempts to share a "file://" URI will result in a
+{@link android.os.FileUriExposedException} to be thrown. If your app needs to share private
+files with other apps, it may use a {@link android.support.v4.content.FileProvider} with
+the {@link android.content.Intent.FLAG_GRANT_READ_URI_PERMISSION}.
+See also <a
+href="{@docRoot}training/secure-file-sharing/index.html">Sharing Files</a>.
+</p>
+
 <p>To read a file from internal storage:</p>
 
 <ol>

diff --git a/docs/html/training/basics/data-storage/files.jd b/docs/html/training/basics/data-storage/files.jd
index 49a9169..983d59a 100644 (file)
--- a/docs/html/training/basics/data-storage/files.jd
+++ b/docs/html/training/basics/data-storage/files.jd
@@ -59,7 +59,7 @@ The following lists summarize the facts about each storage space.</p>
 <p><b>Internal storage:</b></p>
 <ul>
 <li>It's always available.</li>
-<li>Files saved here are accessible by only your app by default.</li>
+<li>Files saved here are accessible by only your app.</li>
 <li>When the user uninstalls your app, the system removes all your app's files from
 internal storage.</li>
 </ul>
@@ -83,6 +83,12 @@ place for files that don't require access restrictions and for files that you wa
 with other apps or allow the user to access with a computer.</p>
 </div>
 
+<p class="note">
+<strong>Note:</strong> Before API level 24, internal files could be made accessible to other
+apps by means of relaxing file system permissions. This is no longer the case. If you wish
+to make the content of a private file accessible to other apps, your app may use the
+{@link android.support.v4.content.FileProvider}. See <a
+href="{@docRoot}training/secure-file-sharing/index.html">Sharing Files</a>.</p>
 
 <p class="note" style="clear:both">
 <strong>Tip:</strong> Although apps are installed onto the internal storage by