Exclude subdirectories when pruning the dex cache.

This requires a companion package manager change to prune
each instruction specific dex cache individually.

bug: 15677279

Change-Id: I5891981512bde20e49bff65b1842c28886f2b177

3 files changed, 29 insertions, 8 deletions

diff --git a/cmds/installd/commands.c b/cmds/installd/commands.c
index 566ce55129..6d6a50d68d 100644
--- a/cmds/installd/commands.c
+++ b/cmds/installd/commands.c
@@ -1384,10 +1384,11 @@ int restorecon_data(const char* pkgName, const char* seinfo, uid_t uid)
 
 static int prune_dex_exclusion_predicate(const char *file_name, const int is_dir)
 {
-    // Don't exclude any directories, we want to inspect them
-    // recusively for files.
+    // Exclude all directories. The top level command will be
+    // given a list of ISA specific directories that are assumed
+    // to be flat.
     if (is_dir) {
-      return 0;
+      return 1;
     }
 
 
@@ -1405,6 +1406,26 @@ static int prune_dex_exclusion_predicate(const char *file_name, const int is_dir
     return 1;
 }
 
-int prune_dex_cache() {
-  return delete_dir_contents(DALVIK_CACHE_PREFIX, 0, &prune_dex_exclusion_predicate);
+int prune_dex_cache(const char* subdir) {
+    // "." is handled as a special case, and refers to
+    // DALVIK_CACHE_PREFIX (usually /data/dalvik-cache).
+    const bool is_dalvik_cache_root = !strcmp(subdir, ".");
+
+    // Don't allow the path to contain "." or ".." except for the
+    // special case above. This is much stricter than we need to be,
+    // but there's no good reason to support them.
+    if (strchr(subdir, '.' ) != NULL && !is_dalvik_cache_root) {
+        return -1;
+    }
+
+    if (!is_dalvik_cache_root) {
+        char full_path[PKG_PATH_MAX];
+        snprintf(full_path, sizeof(full_path), "%s%s", DALVIK_CACHE_PREFIX, subdir);
+        return delete_dir_contents(full_path, 0, &prune_dex_exclusion_predicate);
+    }
+
+
+    // When subdir == ".", clean the contents of the top level
+    // dalvik-cache directory.
+    return delete_dir_contents(DALVIK_CACHE_PREFIX, 0, &prune_dex_exclusion_predicate);
 }
diff --git a/cmds/installd/installd.c b/cmds/installd/installd.c
index 4368a9ecbc..45cc2b267c 100644
--- a/cmds/installd/installd.c
+++ b/cmds/installd/installd.c
@@ -143,7 +143,7 @@ static int do_restorecon_data(char **arg, char reply[REPLY_MAX] __attribute__((u
 static int do_prune_dex_cache(char **arg __attribute__((unused)),
                               char reply[REPLY_MAX] __attribute__((unused)))
 {
-    return prune_dex_cache();
+    return prune_dex_cache(arg[0] /* subdirectory name */);
 }
 
 struct cmdinfo {
@@ -172,7 +172,7 @@ struct cmdinfo cmds[] = {
     { "rmuser",               1, do_rm_user },
     { "idmap",                3, do_idmap },
     { "restorecondata",       3, do_restorecon_data },
-    { "prunedexcache",        0, do_prune_dex_cache },
+    { "prunedexcache",        1, do_prune_dex_cache },
 };
 
 static int readx(int s, void *_buf, int count)
diff --git a/cmds/installd/installd.h b/cmds/installd/installd.h
index c1e6e0fbda..f193b466fd 100644
--- a/cmds/installd/installd.h
+++ b/cmds/installd/installd.h
@@ -220,4 +220,4 @@ int movefiles();
 int linklib(const char* target, const char* source, int userId);
 int idmap(const char *target_path, const char *overlay_path, uid_t uid);
 int restorecon_data();
-int prune_dex_cache();
+int prune_dex_cache(const char* subdir);