liblog: convert to C++

Bug: 119867234
Test: liblog, logcat, logd unit tests

Change-Id: I2a33b6fc37f9860c0041e3573bfb59ea389f623c
diff --git a/liblog/stderr_write.cpp b/liblog/stderr_write.cpp
new file mode 100644
index 0000000..f9cb37d
--- /dev/null
+++ b/liblog/stderr_write.cpp
@@ -0,0 +1,210 @@
+/*
+ * 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.priv = 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.priv) {
+    return fileno(stderr);
+  }
+
+  ctx = static_cast<stderrContext*>(calloc(1, sizeof(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.priv = ctx;
+
+  return fileno(stderr);
+}
+
+static void stderrClose() {
+  stderrContext* ctx = static_cast<stderrContext*>(stderrLoggerWrite.context.priv);
+
+  if (ctx) {
+    stderrLoggerWrite.context.priv = 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;
+  stderrContext* ctx = static_cast<stderrContext*>(stderrLoggerWrite.context.priv);
+
+  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;
+}