uncrypt: split libbootloader_message_writer for reuse.
init and vold also need to write bootloader message, so
split this function from uncrypt into a separate library.
Bug: 27176738
Change-Id: If9b0887b4f6ffab6162d9cb47a6ceb7eedd60b4d
diff --git a/uncrypt/bootloader_message_writer.cpp b/uncrypt/bootloader_message_writer.cpp
new file mode 100644
index 0000000..3bb106a
--- /dev/null
+++ b/uncrypt/bootloader_message_writer.cpp
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2016 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 <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/system_properties.h>
+
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+#include <fs_mgr.h>
+
+#include "bootloader.h"
+
+static struct fstab* read_fstab(std::string* err) {
+ // The fstab path is always "/fstab.${ro.hardware}".
+ std::string fstab_path = "/fstab.";
+ char value[PROP_VALUE_MAX];
+ if (__system_property_get("ro.hardware", value) == 0) {
+ *err = "failed to get ro.hardware";
+ return nullptr;
+ }
+ fstab_path += value;
+ struct fstab* fstab = fs_mgr_read_fstab(fstab_path.c_str());
+ if (fstab == nullptr) {
+ *err = "failed to read " + fstab_path;
+ }
+ return fstab;
+}
+
+static std::string get_misc_blk_device(std::string* err) {
+ struct fstab* fstab = read_fstab(err);
+ if (fstab == nullptr) {
+ return "";
+ }
+ fstab_rec* record = fs_mgr_get_entry_for_mount_point(fstab, "/misc");
+ if (record == nullptr) {
+ *err = "failed to find /misc partition";
+ return "";
+ }
+ return record->blk_device;
+}
+
+static bool write_bootloader_message(const bootloader_message& boot, std::string* err) {
+ std::string misc_blk_device = get_misc_blk_device(err);
+ if (misc_blk_device.empty()) {
+ return false;
+ }
+ android::base::unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY | O_SYNC));
+ if (fd.get() == -1) {
+ *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(),
+ strerror(errno));
+ return false;
+ }
+ if (!android::base::WriteFully(fd.get(), &boot, sizeof(boot))) {
+ *err = android::base::StringPrintf("failed to write %s: %s", misc_blk_device.c_str(),
+ strerror(errno));
+ return false;
+ }
+ // TODO: O_SYNC and fsync duplicates each other?
+ if (fsync(fd.get()) == -1) {
+ *err = android::base::StringPrintf("failed to fsync %s: %s", misc_blk_device.c_str(),
+ strerror(errno));
+ return false;
+ }
+ return true;
+}
+
+bool clear_bootloader_message(std::string* err) {
+ bootloader_message boot = {};
+ return write_bootloader_message(boot, err);
+}
+
+bool write_bootloader_message(const std::vector<std::string>& options, std::string* err) {
+ bootloader_message boot = {};
+ strlcpy(boot.command, "boot-recovery", sizeof(boot.command));
+ strlcpy(boot.recovery, "recovery\n", sizeof(boot.recovery));
+ for (const auto& s : options) {
+ strlcat(boot.recovery, s.c_str(), sizeof(boot.recovery));
+ if (s.back() != '\n') {
+ strlcat(boot.recovery, "\n", sizeof(boot.recovery));
+ }
+ }
+ return write_bootloader_message(boot, err);
+}
+
+extern "C" bool write_bootloader_message(const char* options) {
+ std::string err;
+ return write_bootloader_message({options}, &err);
+}