1 files changed, 128 insertions, 0 deletions
diff --git a/recovery-refresh.cpp b/recovery-refresh.cpp
new file mode 100644
index 000000000..70adc70ee
--- /dev/null
+++ b/recovery-refresh.cpp
@@ -0,0 +1,128 @@
+/*
+ * 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.
+ */
+
+#define LOG_TAG "recovery-refresh"
+
+//
+// Strictly to deal with reboot into system after OTA, then
+// reboot while in system before boot complete landing us back
+// into recovery to continue with any mitigations with retained
+// log history. This simply refreshes the pmsg files from
+// the last pmsg file contents.
+//
+// Usage:
+//    recovery-refresh [--force-rotate|--rotate]
+//
+//    All file content representing in the recovery/ directory stored in
+//    /sys/fs/pstore/pmsg-ramoops-0 in logger format that reside in the
+//    LOG_ID_SYSTEM buffer at ANDROID_LOG_INFO priority or higher is
+//    refreshed into /dev/pmsg0. This ensures that an unexpected reboot
+//    before recovery-persist is run will still contain the associated
+//    pmsg Android Logger content.
+//
+//    --force-rotate  recovery/last_kmsg and recovery.last_log files are
+//                    rotated with .<number> suffixes upwards.
+//    --rotate        rotated only if rocovery/last_msg or recovery/last_log
+//                    exist, otherwise perform 1:1 refresh.
+//
+
+#include <string.h>
+
+#include <string>
+
+#include <android/log.h> /* Android Log Priority Tags */
+#include <log/logger.h> /* Android Log packet format */
+#include <private/android_logger.h> /* private pmsg functions */
+
+static const char LAST_KMSG_FILE[] = "recovery/last_kmsg";
+static const char LAST_LOG_FILE[] = "recovery/last_log";
+
+static ssize_t logbasename(
+        log_id_t /* logId */,
+        char /* prio */,
+        const char *filename,
+        const char * /* buf */, size_t len,
+        void *arg) {
+    if (strstr(LAST_KMSG_FILE, filename) ||
+            strstr(LAST_LOG_FILE, filename)) {
+        bool *doRotate = reinterpret_cast<bool *>(arg);
+        *doRotate = true;
+    }
+    return len;
+}
+
+static ssize_t logrotate(
+        log_id_t logId,
+        char prio,
+        const char *filename,
+        const char *buf, size_t len,
+        void *arg) {
+    bool *doRotate = reinterpret_cast<bool *>(arg);
+    if (!*doRotate) {
+        return __android_log_pmsg_file_write(logId, prio, filename, buf, len);
+    }
+
+    std::string name(filename);
+    size_t dot = name.find_last_of(".");
+    std::string sub = name.substr(0, dot);
+
+    if (!strstr(LAST_KMSG_FILE, sub.c_str()) &&
+                !strstr(LAST_LOG_FILE, sub.c_str())) {
+        return __android_log_pmsg_file_write(logId, prio, filename, buf, len);
+    }
+
+    // filename rotation
+    if (dot == std::string::npos) {
+        name += ".1";
+    } else {
+        std::string number = name.substr(dot + 1);
+        if (!isdigit(number.data()[0])) {
+            name += ".1";
+        } else {
+            unsigned long long i = std::stoull(number);
+            name = sub + "." + std::to_string(i + 1);
+        }
+    }
+
+    return __android_log_pmsg_file_write(logId, prio, name.c_str(), buf, len);
+}
+
+int main(int argc, char **argv) {
+    static const char filter[] = "recovery/";
+    static const char force_rotate_flag[] = "--force-rotate";
+    static const char rotate_flag[] = "--rotate";
+    ssize_t ret;
+    bool doRotate = false;
+
+    // Take last pmsg contents and rewrite it to the current pmsg session.
+    if ((argc <= 1) || !argv[1] ||
+            (((doRotate = strcmp(argv[1], rotate_flag))) &&
+                strcmp(argv[1], force_rotate_flag))) {
+        doRotate = false;
+    } else if (!doRotate) {
+        // Do we need to rotate?
+        __android_log_pmsg_file_read(
+            LOG_ID_SYSTEM, ANDROID_LOG_INFO, filter,
+            logbasename, &doRotate);
+    }
+
+    // Take action to refresh pmsg contents
+    ret = __android_log_pmsg_file_read(
+        LOG_ID_SYSTEM, ANDROID_LOG_INFO, filter,
+        logrotate, &doRotate);
+
+    return (ret < 0) ? ret : 0;
+}