edify extensions for OTA package installation, part 1

Adds the following edify functions:

  mount unmount format show_progress delete delete_recursive
  package_extract symlink set_perm set_perm_recursive

This set is enough to extract and install the system part of a (full)
OTA package.

Adds the updater binary that extracts an edify script from the OTA
package and then executes it.  Minor changes to the edify core (adds a
sleep() builtin for debugging, adds "." to the set of characters that
can appear in an unquoted string).
diff --git a/updater/updater.c b/updater/updater.c
new file mode 100644
index 0000000..aa03803
--- /dev/null
+++ b/updater/updater.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "edify/expr.h"
+#include "updater.h"
+#include "install.h"
+#include "minzip/Zip.h"
+
+// Where in the package we expect to find the edify script to execute.
+// (Note it's "updateR-script", not the older "update-script".)
+#define SCRIPT_NAME "META-INF/com/google/android/updater-script"
+
+int main(int argc, char** argv) {
+    if (argc != 4) {
+        fprintf(stderr, "unexpected number of arguments (%d)\n", argc);
+        return 1;
+    }
+
+    char* version = argv[1];
+    if (version[0] != '1' || version[1] != '\0') {
+        fprintf(stderr, "wrong updater binary API; expected 1, got %s\n",
+                version);
+        return 2;
+    }
+
+    // Set up the pipe for sending commands back to the parent process.
+
+    int fd = atoi(argv[2]);
+    FILE* cmd_pipe = fdopen(fd, "wb");
+    setlinebuf(cmd_pipe);
+
+    // Extract the script from the package.
+
+    char* package_data = argv[3];
+    ZipArchive za;
+    int err;
+    err = mzOpenZipArchive(package_data, &za);
+    if (err != 0) {
+        fprintf(stderr, "failed to open package %s: %s\n",
+                package_data, strerror(err));
+        return 3;
+    }
+
+    const ZipEntry* script_entry = mzFindZipEntry(&za, SCRIPT_NAME);
+    if (script_entry == NULL) {
+        fprintf(stderr, "failed to find %s in %s\n", SCRIPT_NAME, package_data);
+        return 4;
+    }
+
+    char* script = malloc(script_entry->uncompLen+1);
+    if (!mzReadZipEntry(&za, script_entry, script, script_entry->uncompLen)) {
+        fprintf(stderr, "failed to read script from package\n");
+        return 5;
+    }
+    script[script_entry->uncompLen] = '\0';
+
+    // Configure edify's functions.
+
+    RegisterBuiltins();
+    RegisterInstallFunctions();
+    FinishRegistration();
+
+    // Parse the script.
+
+    Expr* root;
+    yy_scan_string(script);
+    int error = yyparse(&root);
+    if (error != 0) {
+        fprintf(stderr, "%d parse errors\n", error);
+        return 6;
+    }
+
+    // Evaluate the parsed script.
+
+    UpdaterInfo updater_info;
+    updater_info.cmd_pipe = cmd_pipe;
+    updater_info.package_zip = &za;
+
+    char* result = Evaluate(&updater_info, root);
+    if (result == NULL) {
+        const char* errmsg = GetError();
+        fprintf(stderr, "script aborted with error: %s\n",
+                errmsg == NULL ? "(none)" : errmsg);
+        ClearError();
+        return 7;
+    } else {
+        fprintf(stderr, "script result was [%s]\n", result);
+        free(result);
+    }
+
+    mzCloseZipArchive(&za);
+
+    return 0;
+}