Save multiple copies of update engine logs
Right now we only have one copy of update engine log; and it's
overwritten if the device reboots or update engine restarts. This CL
save multiple copies of the logs with timestamp in
"/data/misc/update_engine_log/". It also implements a function to
keep the most recent five logs but delete the old ones.
Bug: 72080233
Test: Logs are created with correct permission; and old logs are deleted
when update engine starts.
Change-Id: I9853546bce879e7fbd6380419a85e01256331247
diff --git a/main.cc b/main.cc
index 0b96307..0612c54 100644
--- a/main.cc
+++ b/main.cc
@@ -14,15 +14,19 @@
// limitations under the License.
//
+#include <inttypes.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <xz.h>
+#include <algorithm>
#include <string>
+#include <vector>
#include <base/at_exit.h>
#include <base/command_line.h>
+#include <base/files/dir_reader_posix.h>
#include <base/files/file_util.h>
#include <base/logging.h>
#include <base/strings/string_util.h>
@@ -38,7 +42,65 @@
namespace chromeos_update_engine {
namespace {
-#ifndef __ANDROID__
+string GetTimeAsString(time_t utime) {
+ struct tm tm;
+ CHECK_EQ(localtime_r(&utime, &tm), &tm);
+ char str[16];
+ CHECK_EQ(strftime(str, sizeof(str), "%Y%m%d-%H%M%S", &tm), 15u);
+ return str;
+}
+
+#ifdef __ANDROID__
+constexpr char kSystemLogsRoot[] = "/data/misc/update_engine_log";
+constexpr size_t kLogCount = 5;
+
+// Keep the most recent |kLogCount| logs but remove the old ones in
+// "/data/misc/update_engine_log/".
+void DeleteOldLogs(const string& kLogsRoot) {
+ base::DirReaderPosix reader(kLogsRoot.c_str());
+ if (!reader.IsValid()) {
+ LOG(ERROR) << "Failed to read " << kLogsRoot;
+ return;
+ }
+
+ std::vector<string> old_logs;
+ while (reader.Next()) {
+ if (reader.name()[0] == '.')
+ continue;
+
+ // Log files are in format "update_engine.%Y%m%d-%H%M%S",
+ // e.g. update_engine.20090103-231425
+ uint64_t date;
+ uint64_t local_time;
+ if (sscanf(reader.name(),
+ "update_engine.%" PRIu64 "-%" PRIu64 "",
+ &date,
+ &local_time) == 2) {
+ old_logs.push_back(reader.name());
+ } else {
+ LOG(WARNING) << "Unrecognized log file " << reader.name();
+ }
+ }
+
+ std::sort(old_logs.begin(), old_logs.end(), std::greater<string>());
+ for (size_t i = kLogCount; i < old_logs.size(); i++) {
+ string log_path = kLogsRoot + "/" + old_logs[i];
+ if (unlink(log_path.c_str()) == -1) {
+ PLOG(WARNING) << "Failed to unlink " << log_path;
+ }
+ }
+}
+
+string SetupLogFile(const string& kLogsRoot) {
+ DeleteOldLogs(kLogsRoot);
+
+ return base::StringPrintf("%s/update_engine.%s",
+ kLogsRoot.c_str(),
+ GetTimeAsString(::time(nullptr)).c_str());
+}
+#else
+constexpr char kSystemLogsRoot[] = "/var/log";
+
void SetupLogSymlink(const string& symlink_path, const string& log_path) {
// TODO(petkov): To ensure a smooth transition between non-timestamped and
// timestamped logs, move an existing log to start the first timestamped
@@ -57,14 +119,6 @@
}
}
-string GetTimeAsString(time_t utime) {
- struct tm tm;
- CHECK_EQ(localtime_r(&utime, &tm), &tm);
- char str[16];
- CHECK_EQ(strftime(str, sizeof(str), "%Y%m%d-%H%M%S", &tm), 15u);
- return str;
-}
-
string SetupLogFile(const string& kLogsRoot) {
const string kLogSymlink = kLogsRoot + "/update_engine.log";
const string kLogsDir = kLogsRoot + "/update_engine";
@@ -88,13 +142,8 @@
string log_file;
if (log_to_file) {
-#ifdef __ANDROID__
- log_file = "/data/misc/update_engine_log/update_engine.log";
- log_settings.delete_old = logging::DELETE_OLD_LOG_FILE;
-#else
- log_file = SetupLogFile("/var/log");
+ log_file = SetupLogFile(kSystemLogsRoot);
log_settings.delete_old = logging::APPEND_TO_OLD_LOG_FILE;
-#endif // __ANDROID__
log_settings.log_file = log_file.c_str();
}
logging::InitLogging(log_settings);