Make 'idmap --scan' accept more than one input directory

The 'idmap --scan' command was limited to only scan a single directory
for overlay packages. Update idmap to support any number of directories.

Change-Id: I851f5720a3c1d844235911a0833670652a20a3c8
diff --git a/cmds/idmap/idmap.cpp b/cmds/idmap/idmap.cpp
index 90cfa2c..3ab1915 100644
--- a/cmds/idmap/idmap.cpp
+++ b/cmds/idmap/idmap.cpp
@@ -13,7 +13,8 @@
       idmap --help \n\
       idmap --fd target overlay fd \n\
       idmap --path target overlay idmap \n\
-      idmap --scan dir-to-scan target-to-look-for target dir-to-hold-idmaps \n\
+      idmap --scan target-package-name-to-look-for path-to-target-apk dir-to-hold-idmaps \\\
+                   dir-to-scan [additional-dir-to-scan [additional-dir-to-scan [...]]]\n\
       idmap --inspect idmap \n\
 \n\
 DESCRIPTION \n\
@@ -49,9 +50,9 @@
               'overlay' (path to apk); write results to 'idmap' (path). \n\
 \n\
       --scan: non-recursively search directory 'dir-to-scan' (path) for overlay packages with \n\
-              target package 'target-to-look-for' (package name) present at 'target' (path to \n\
-              apk). For each overlay package found, create an idmap file in 'dir-to-hold-idmaps' \n\
-              (path). \n\
+              target package 'target-package-name-to-look-for' (package name) present at\n\
+              'path-to-target-apk' (path to apk). For each overlay package found, create an\n\
+              idmap file in 'dir-to-hold-idmaps' (path). \n\
 \n\
       --inspect: decode the binary format of 'idmap' (path) and display the contents in a \n\
                  debug-friendly format. \n\
@@ -166,19 +167,14 @@
         return idmap_create_path(target_apk_path, overlay_apk_path, idmap_path);
     }
 
-    int maybe_scan(const char *overlay_dir, const char *target_package_name,
-            const char *target_apk_path, const char *idmap_dir)
+    int maybe_scan(const char *target_package_name, const char *target_apk_path,
+            const char *idmap_dir, const android::Vector<const char *> *overlay_dirs)
     {
         if (!verify_root_or_system()) {
             fprintf(stderr, "error: permission denied: not user root or user system\n");
             return -1;
         }
 
-        if (!verify_directory_readable(overlay_dir)) {
-            ALOGD("error: no read access to %s: %s\n", overlay_dir, strerror(errno));
-            return -1;
-        }
-
         if (!verify_file_readable(target_apk_path)) {
             ALOGD("error: failed to read apk %s: %s\n", target_apk_path, strerror(errno));
             return -1;
@@ -189,7 +185,16 @@
             return -1;
         }
 
-        return idmap_scan(overlay_dir, target_package_name, target_apk_path, idmap_dir);
+        const size_t N = overlay_dirs->size();
+        for (size_t i = 0; i < N; i++) {
+            const char *dir = overlay_dirs->itemAt(i);
+            if (!verify_directory_readable(dir)) {
+                ALOGD("error: no read access to %s: %s\n", dir, strerror(errno));
+                return -1;
+            }
+        }
+
+        return idmap_scan(target_package_name, target_apk_path, idmap_dir, overlay_dirs);
     }
 
     int maybe_inspect(const char *idmap_path)
@@ -230,8 +235,12 @@
         return maybe_create_path(argv[2], argv[3], argv[4]);
     }
 
-    if (argc == 6 && !strcmp(argv[1], "--scan")) {
-        return maybe_scan(argv[2], argv[3], argv[4], argv[5]);
+    if (argc >= 6 && !strcmp(argv[1], "--scan")) {
+        android::Vector<const char *> v;
+        for (int i = 5; i < argc; i++) {
+            v.push(argv[i]);
+        }
+        return maybe_scan(argv[2], argv[3], argv[4], &v);
     }
 
     if (argc == 3 && !strcmp(argv[1], "--inspect")) {