Fix issue #6926562: Ensure all multi-user cache files are managed correctly

Now we correctly iterate through the different user cache dirs.

Also update documentation to describe the new cache pruning behavior,
and deprecate the file modes for making files world readable/writable
which we really don't want people using any more.

Change-Id: I3708df3ddc697b1f5c511143cce7cc40a5a3d0bd

1 files changed, 24 insertions, 5 deletions

diff --git a/cmds/installd/commands.c b/cmds/installd/commands.c
index 2934261..a9945b7 100644
--- a/cmds/installd/commands.c
+++ b/cmds/installd/commands.c
@@ -338,13 +338,32 @@ int free_cache(int64_t free_size)
         closedir(d);
     }
 
-    // Collect cache files on external storage (if it is mounted as part
+    // Collect cache files on external storage for all users (if it is mounted as part
     // of the internal storage).
     strcpy(tmpdir, android_media_dir.path);
-    if (lookup_media_dir(tmpdir, "Android") == 0
-            && lookup_media_dir(tmpdir, "data") == 0) {
-        //ALOGI("adding cache files from %s\n", tmpdir);
-        add_cache_files(cache, tmpdir, "cache");
+    dirpos = tmpdir + strlen(tmpdir);
+    d = opendir(tmpdir);
+    if (d != NULL) {
+        while ((de = readdir(d))) {
+            if (de->d_type == DT_DIR) {
+                const char *name = de->d_name;
+                    /* skip any dir that doesn't start with a number, so not a user */
+                if (name[0] < '0' || name[0] > '9') {
+                    continue;
+                }
+                if ((strlen(name)+(dirpos-tmpdir)) < (sizeof(tmpdir)-1)) {
+                    strcpy(dirpos, name);
+                    if (lookup_media_dir(tmpdir, "Android") == 0
+                            && lookup_media_dir(tmpdir, "data") == 0) {
+                        //ALOGI("adding cache files from %s\n", tmpdir);
+                        add_cache_files(cache, tmpdir, "cache");
+                    }
+                } else {
+                    ALOGW("Path exceeds limit: %s%s", tmpdir, name);
+                }
+            }
+        }
+        closedir(d);
     }
 
     clear_cache_files(cache, free_size);