liblog: add LOGGER_STDERR frontend
Standalone, this logger provides no end-to-end capability. Only
provides a writer, no reader transport. All output goes, logcat-like,
into the stderr stream. Output can be adjusted with environment
variables ANDROID_PRINTF_LOG and ANDROID_LOG_TAGS.
liblog_*.__android_log_bswrite_and_print___max print fails if a string
member is truncated with "Binary log entry conversion failed" and -1.
We expose the truncated content in the tests and in LOGGER_STDERR.
The purpose of this transport selection is for command-line tools,
providing a means to shunt the logs to be mixed in with the tool's
error stream.
Test: gTest liblog-unit-tests
Bug: 27405083
Change-Id: If344b6e3e67df2dc86ce317cfad8af8e857727b7
diff --git a/liblog/stderr_write.c b/liblog/stderr_write.c
new file mode 100644
index 0000000..b739299
--- /dev/null
+++ b/liblog/stderr_write.c
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+/*
+ * stderr write handler. Output is logcat-like, and responds to
+ * logcat's environment variables ANDROID_PRINTF_LOG and
+ * ANDROID_LOG_TAGS to filter output.
+ *
+ * This transport only provides a writer, that means that it does not
+ * provide an End-To-End capability as the logs are effectively _lost_
+ * to the stderr file stream. The purpose of this transport is to
+ * supply a means for command line tools to report their logging
+ * to the stderr stream, in line with all other activities.
+ */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <log/event_tag_map.h>
+#include <log/log.h>
+#include <log/logprint.h>
+#include <log/uio.h>
+
+#include "log_portability.h"
+#include "logger.h"
+
+static int stderrOpen();
+static void stderrClose();
+static int stderrAvailable(log_id_t logId);
+static int stderrWrite(log_id_t logId, struct timespec* ts,
+ struct iovec* vec, size_t nr);
+
+struct stderrContext {
+ AndroidLogFormat* logformat;
+#if defined(__ANDROID__)
+ EventTagMap* eventTagMap;
+#endif
+};
+
+LIBLOG_HIDDEN struct android_log_transport_write stderrLoggerWrite = {
+ .node = { &stderrLoggerWrite.node, &stderrLoggerWrite.node },
+ .context.private = NULL,
+ .name = "stderr",
+ .available = stderrAvailable,
+ .open = stderrOpen,
+ .close = stderrClose,
+ .write = stderrWrite,
+};
+
+static int stderrOpen()
+{
+ struct stderrContext* ctx;
+ const char* envStr;
+ bool setFormat;
+
+ if (!stderr || (fileno(stderr) < 0)) {
+ return -EBADF;
+ }
+
+ if (stderrLoggerWrite.context.private) {
+ return fileno(stderr);
+ }
+
+ ctx = calloc(1, sizeof(struct stderrContext));
+ if (!ctx) {
+ return -ENOMEM;
+ }
+
+ ctx->logformat = android_log_format_new();
+ if (!ctx->logformat) {
+ free(ctx);
+ return -ENOMEM;
+ }
+
+ envStr = getenv("ANDROID_PRINTF_LOG");
+ setFormat = false;
+
+ if (envStr) {
+ char* formats = strdup(envStr);
+ char* sv = NULL;
+ char* arg = formats;
+ while (!!(arg = strtok_r(arg, ",:; \t\n\r\f", &sv))) {
+ AndroidLogPrintFormat format = android_log_formatFromString(arg);
+ arg = NULL;
+ if (format == FORMAT_OFF) {
+ continue;
+ }
+ if (android_log_setPrintFormat(ctx->logformat, format) <= 0) {
+ continue;
+ }
+ setFormat = true;
+ }
+ free(formats);
+ }
+ if (!setFormat) {
+ AndroidLogPrintFormat format = android_log_formatFromString(
+ "threadtime");
+ android_log_setPrintFormat(ctx->logformat, format);
+ }
+ envStr = getenv("ANDROID_LOG_TAGS");
+ if (envStr) {
+ android_log_addFilterString(ctx->logformat, envStr);
+ }
+ stderrLoggerWrite.context.private = ctx;
+
+ return fileno(stderr);
+}
+
+static void stderrClose()
+{
+ struct stderrContext* ctx = stderrLoggerWrite.context.private;
+
+ if (ctx) {
+ stderrLoggerWrite.context.private = NULL;
+ if (ctx->logformat) {
+ android_log_format_free(ctx->logformat);
+ ctx->logformat = NULL;
+ }
+#if defined(__ANDROID__)
+ if (ctx->eventTagMap) {
+ android_closeEventTagMap(ctx->eventTagMap);
+ ctx->eventTagMap = NULL;
+ }
+#endif
+ }
+}
+
+static int stderrAvailable(log_id_t logId)
+{
+ if ((logId >= LOG_ID_MAX) || (logId == LOG_ID_KERNEL)) {
+ return -EINVAL;
+ }
+ return 1;
+}
+
+static int stderrWrite(log_id_t logId, struct timespec* ts,
+ struct iovec* vec, size_t nr)
+{
+ struct log_msg log_msg;
+ AndroidLogEntry entry;
+ char binaryMsgBuf[1024];
+ int err;
+ size_t i;
+ struct stderrContext* ctx = stderrLoggerWrite.context.private;
+
+ if (!ctx) return -EBADF;
+ if (!vec || !nr) return -EINVAL;
+
+ log_msg.entry.len = 0;
+ log_msg.entry.hdr_size = sizeof(log_msg.entry);
+ log_msg.entry.pid = getpid();
+#ifdef __BIONIC__
+ log_msg.entry.tid = gettid();
+#else
+ log_msg.entry.tid = getpid();
+#endif
+ log_msg.entry.sec = ts->tv_sec;
+ log_msg.entry.nsec = ts->tv_nsec;
+ log_msg.entry.lid = logId;
+ log_msg.entry.uid = __android_log_uid();
+
+ for (i = 0; i < nr; ++i) {
+ size_t len = vec[i].iov_len;
+ if ((log_msg.entry.len + len) > LOGGER_ENTRY_MAX_PAYLOAD) {
+ len = LOGGER_ENTRY_MAX_PAYLOAD - log_msg.entry.len;
+ }
+ if (!len) continue;
+ memcpy(log_msg.entry.msg + log_msg.entry.len, vec[i].iov_base, len);
+ log_msg.entry.len += len;
+ }
+
+ if ((logId == LOG_ID_EVENTS) || (logId == LOG_ID_SECURITY)) {
+#if defined(__ANDROID__)
+ if (!ctx->eventTagMap) {
+ ctx->eventTagMap = android_openEventTagMap(NULL);
+ }
+#endif
+ err = android_log_processBinaryLogBuffer(&log_msg.entry_v1,
+ &entry,
+#if defined(__ANDROID__)
+ ctx->eventTagMap,
+#else
+ NULL,
+#endif
+ binaryMsgBuf,
+ sizeof(binaryMsgBuf));
+ } else {
+ err = android_log_processLogBuffer(&log_msg.entry_v1, &entry);
+ }
+
+ /* print known truncated data, in essence logcat --debug */
+ if ((err < 0) && !entry.message) return -EINVAL;
+
+ if (!android_log_shouldPrintLine(ctx->logformat, entry.tag, entry.priority)) {
+ return log_msg.entry.len;
+ }
+
+ err = android_log_printLogLine(ctx->logformat, fileno(stderr), &entry);
+ if (err < 0) return errno ? -errno : -EINVAL;
+ return log_msg.entry.len;
+}