src/main/cpp/gzcompressaction.cpp

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

#include <log4cxx/rolling/gzcompressaction.h>
#include <apr_thread_proc.h>
#include <apr_strings.h>
#include <log4cxx/helpers/exception.h>
#include <log4cxx/helpers/transcoder.h>
#include <log4cxx/private/action_priv.h>
#include <log4cxx/helpers/loglog.h>

using namespace LOG4CXX_NS;
using namespace LOG4CXX_NS::rolling;
using namespace LOG4CXX_NS::helpers;

#define priv static_cast<GZCompressActionPrivate*>(m_priv.get())

struct GZCompressAction::GZCompressActionPrivate : public ActionPrivate
{
	GZCompressActionPrivate( const File& toRename,
		const File& renameTo,
		bool deleteSource):
		source(toRename), destination(renameTo), deleteSource(deleteSource) {}

	const File source;
	File destination;
	bool deleteSource;
	bool throwIOExceptionOnForkFailure = true;
};

IMPLEMENT_LOG4CXX_OBJECT(GZCompressAction)

GZCompressAction::GZCompressAction(const File& src,
	const File& dest,
	bool del)
	: Action(std::make_unique<GZCompressActionPrivate>(
			  src, dest, del))
{
}

GZCompressAction::~GZCompressAction() {}

bool GZCompressAction::execute(LOG4CXX_NS::helpers::Pool& p) const
{
	if (exists(p, priv->source))
	{
		apr_pool_t* aprpool = p.getAPRPool();
		apr_procattr_t* attr;
		apr_status_t stat = apr_procattr_create(&attr, aprpool);

		if (stat != APR_SUCCESS)
		{
			throw IOException(stat);
		}

		stat = apr_procattr_io_set(attr, APR_NO_PIPE, APR_FULL_BLOCK, APR_FULL_BLOCK);

		if (stat != APR_SUCCESS)
		{
			throw IOException(stat);
		}

		stat = apr_procattr_cmdtype_set(attr, APR_PROGRAM_PATH);

		if (stat != APR_SUCCESS)
		{
			throw IOException(stat);
		}

		//
		//   set child process output to destination file
		//
		apr_file_t* child_out;
		apr_int32_t flags = APR_FOPEN_READ | APR_FOPEN_WRITE |
			APR_FOPEN_CREATE | APR_FOPEN_TRUNCATE;
		stat = openFile(priv->destination, &child_out, flags, APR_OS_DEFAULT, p);

		if (stat != APR_SUCCESS)
		{
			throw IOException(stat);
		}

		stat =  apr_procattr_child_out_set(attr, child_out, NULL);

		if (stat != APR_SUCCESS)
		{
			throw IOException(stat);
		}

		//
		//   redirect the child's error stream to this processes' error stream
		//
		apr_file_t* child_err;
		stat = apr_file_open_stderr(&child_err, aprpool);

		if (stat == APR_SUCCESS)
		{
			stat =  apr_procattr_child_err_set(attr, child_err, NULL);

			if (stat != APR_SUCCESS)
			{
				throw IOException(stat);
			}
		}

		const char** args = (const char**)
			apr_palloc(aprpool, 4 * sizeof(*args));
		int i = 0;
		args[i++] = "gzip";
		args[i++] = "-c";
		args[i++] = Transcoder::encode(getPath(priv->source), p);
		args[i++] = NULL;

		apr_proc_t pid;
		stat = apr_proc_create(&pid, "gzip", args, NULL, attr, aprpool);

		if (stat != APR_SUCCESS && priv->throwIOExceptionOnForkFailure)
		{
			deleteFile(p, priv->destination);
			throw IOException(stat);
		}
		else if(stat != APR_SUCCESS && !priv->throwIOExceptionOnForkFailure)
		{
			/* If we fail here (to create the gzip child process),
			 * skip the compression and consider the rotation to be
			 * otherwise successful. The caller has already rotated
			 * the log file (`source` here refers to the
			 * uncompressed, rotated path, and `destination` the
			 * same path with `.gz` appended). Remove the empty
			 * destination file and leave source as-is.
			 */
			LogLog::warn(LOG4CXX_STR("Failed to fork gzip during log rotation; leaving log file uncompressed"));
			stat = apr_file_close(child_out);
			if (stat != APR_SUCCESS)
			{
				LogLog::warn(LOG4CXX_STR("Failed to close abandoned .gz file; ignoring"));
			}
			deleteFile(p, priv->destination);
			return true;
		}

		apr_proc_wait(&pid, NULL, NULL, APR_WAIT);
		stat = apr_file_close(child_out);

		if (stat != APR_SUCCESS)
		{
			throw IOException(stat);
		}

		if (priv->deleteSource)
		{
			deleteFile(p, priv->source);
		}

		return true;
	}

	return false;
}

void GZCompressAction::setThrowIOExceptionOnForkFailure(bool throwIO){
	priv->throwIOExceptionOnForkFailure = throwIO;
}