1 files changed, 200 insertions, 0 deletions

diff --git a/recovery-persist.cpp b/recovery-persist.cpp
new file mode 100644
index 000000000..8587e9a66
--- /dev/null
+++ b/recovery-persist.cpp
@@ -0,0 +1,200 @@
+/*
+ * 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-persist"
+
+//
+// Strictly to deal with reboot into system after OTA after /data
+// mounts to pull the last pmsg file data and place it
+// into /data/misc/recovery/ directory, rotating it in.
+//
+// Usage: recovery-persist [--force-persist]
+//
+//    On systems without /cache mount, 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 transfered to the /data/misc/recovery/ directory.
+//    The content is matched and rotated in as need be.
+//
+//    --force-persist  ignore /cache mount, always rotate in the contents.
+//
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <string>
+
+#include <android/log.h> /* Android Log Priority Tags */
+#include <android-base/file.h>
+#include <log/log.h>
+#include <log/logger.h> /* Android Log packet format */
+#include <private/android_logger.h> /* private pmsg functions */
+
+static const char *LAST_LOG_FILE = "/data/misc/recovery/last_log";
+static const char *LAST_PMSG_FILE = "/sys/fs/pstore/pmsg-ramoops-0";
+static const char *LAST_KMSG_FILE = "/data/misc/recovery/last_kmsg";
+static const char *LAST_CONSOLE_FILE = "/sys/fs/pstore/console-ramoops-0";
+
+static const int KEEP_LOG_COUNT = 10;
+
+// close a file, log an error if the error indicator is set
+static void check_and_fclose(FILE *fp, const char *name) {
+    fflush(fp);
+    if (ferror(fp)) SLOGE("%s %s", name, strerror(errno));
+    fclose(fp);
+}
+
+static void copy_file(const char* source, const char* destination) {
+    FILE* dest_fp = fopen(destination, "w");
+    if (dest_fp == nullptr) {
+        SLOGE("%s %s", destination, strerror(errno));
+    } else {
+        FILE* source_fp = fopen(source, "r");
+        if (source_fp != nullptr) {
+            char buf[4096];
+            size_t bytes;
+            while ((bytes = fread(buf, 1, sizeof(buf), source_fp)) != 0) {
+                fwrite(buf, 1, bytes, dest_fp);
+            }
+            check_and_fclose(source_fp, source);
+        }
+        check_and_fclose(dest_fp, destination);
+    }
+}
+
+static bool rotated = false;
+
+// Rename last_log -> last_log.1 -> last_log.2 -> ... -> last_log.$max.
+// Similarly rename last_kmsg -> last_kmsg.1 -> ... -> last_kmsg.$max.
+// Overwrite any existing last_log.$max and last_kmsg.$max.
+static void rotate_logs(int max) {
+    // Logs should only be rotated once.
+
+    if (rotated) {
+        return;
+    }
+    rotated = true;
+
+    for (int i = max-1; i >= 0; --i) {
+        std::string old_log(LAST_LOG_FILE);
+        if (i > 0) {
+          old_log += "." + std::to_string(i);
+        }
+        std::string new_log(LAST_LOG_FILE);
+        new_log += "." + std::to_string(i+1);
+
+        // Ignore errors if old_log doesn't exist.
+        rename(old_log.c_str(), new_log.c_str());
+
+        std::string old_kmsg(LAST_KMSG_FILE);
+        if (i > 0) {
+          old_kmsg += "." + std::to_string(i);
+        }
+        std::string new_kmsg(LAST_KMSG_FILE);
+        new_kmsg += "." + std::to_string(i+1);
+
+        rename(old_kmsg.c_str(), new_kmsg.c_str());
+    }
+}
+
+ssize_t logsave(
+        log_id_t /* logId */,
+        char /* prio */,
+        const char *filename,
+        const char *buf, size_t len,
+        void * /* arg */) {
+
+    std::string destination("/data/misc/");
+    destination += filename;
+
+    std::string buffer(buf, len);
+
+    {
+        std::string content;
+        android::base::ReadFileToString(destination, &content);
+
+        if (buffer.compare(content) == 0) {
+            return len;
+        }
+    }
+
+    // ToDo: Any others that match? Are we pulling in multiple
+    // already-rotated files? Algorithm thus far is KISS: one file,
+    // one rotation allowed.
+
+    rotate_logs(KEEP_LOG_COUNT);
+
+    return android::base::WriteStringToFile(buffer, destination.c_str());
+}
+
+int main(int argc, char **argv) {
+
+    /* Is /cache a mount?, we have been delivered where we are not wanted */
+    /*
+     * Following code halves the size of the executable as compared to:
+     *
+     *    load_volume_table();
+     *    has_cache = volume_for_path(CACHE_ROOT) != nullptr;
+     */
+    bool has_cache = false;
+    static const char mounts_file[] = "/proc/mounts";
+    FILE *fp = fopen(mounts_file, "r");
+    if (!fp) {
+        SLOGV("%s %s", mounts_file, strerror(errno));
+    } else {
+        char *line = NULL;
+        size_t len = 0;
+        ssize_t read;
+        while ((read = getline(&line, &len, fp)) != -1) {
+            if (strstr(line, " /cache ")) {
+                has_cache = true;
+                break;
+            }
+        }
+        free(line);
+        fclose(fp);
+    }
+
+    if (has_cache) {
+        /*
+         * TBD: Future location to move content from
+         * /cache/recovery to /data/misc/recovery/
+         */
+        /* if --force-persist flag, then transfer pmsg data anyways */
+        if ((argc <= 1) || !argv[1] || strcmp(argv[1], "--force-persist")) {
+            return 0;
+        }
+    }
+
+    /* Is there something in pmsg? */
+    if (access(LAST_PMSG_FILE, R_OK)) {
+        return 0;
+    }
+
+    // Take last pmsg file contents and send it off to the logsave
+    __android_log_pmsg_file_read(
+        LOG_ID_SYSTEM, ANDROID_LOG_INFO, "recovery/", logsave, NULL);
+
+    /* Is there a last console log too? */
+    if (rotated && !access(LAST_CONSOLE_FILE, R_OK)) {
+        copy_file(LAST_CONSOLE_FILE, LAST_KMSG_FILE);
+    }
+
+    return 0;
+}