fdfs_upload_file发送内存文件

这里只对fdfs_upload_file进行改造，至于其他的也是一样的原理：
在进行fdfs_upload_file的时候，如果是程序中需要实现这个功能，一种方法是使用子进程的逻辑直接调用该程序，这种处理方式需要一个临时文件，而且还需要进程的创建销毁。
另外一种思路是直接参考fdfs_upload_file源码去直接上传文件，fdfs本身就提供了一种直接上传内存缓冲的接口，对fdfs_upload_file.c源码稍加改造就可以直接使用源码实现上传文件的功能：

/**
* Copyright (C) 2008 Happy Fish / YuQing
*
* FastDFS may be copied only under the terms of the GNU General
* Public License V3, which may be found in the FastDFS source kit.
* Please visit the FastDFS Home Page http://www.fastken.com/ for more detail.
**/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "fdfs_client.h"
#include "fdfs_global.h"
#include "fastcommon/base64.h"
#include "fastcommon/sockopt.h"
#include "fastcommon/logger.h"
#include "fdfs_http_shared.h"
#include <unistd.h>

/**
 * @brief 
 * @param  fileName         文件名称
 * @param  confFileName     client配置路径
 * @param  fileSize         文件内容大小
 * @param  buf              文件内容内存缓冲区
 * @return int 
 */
int fdfs_upload_file(char* fileName, char* confFileName, int fileSize, char* buf)
{
    char *conf_filename;
	char *local_filename;
	char group_name[FDFS_GROUP_NAME_MAX_LEN + 1];
	ConnectionInfo *pTrackerServer;
	int result;
	int store_path_index;
	ConnectionInfo storageServer;
	char file_id[128];

	log_init();
	g_log_context.log_level = LOG_ERR;
	ignore_signal_pipe();

	conf_filename = confFileName;
	if ((result=fdfs_client_init(conf_filename)) != 0)
	{
		return result;
	}

	pTrackerServer = tracker_get_connection();
	if (pTrackerServer == NULL)
	{
		fdfs_client_destroy();
		return errno != 0 ? errno : ECONNREFUSED;
	}

	local_filename = fileName;
	*group_name = '\0';
	if ((result=tracker_query_storage_store(pTrackerServer, \
	                &storageServer, group_name, &store_path_index)) != 0)
	{
		fdfs_client_destroy();
		fprintf(stderr, "tracker_query_storage fail, " \
			"error no: %d, error info: %s\n", \
			result, STRERROR(result));
		return result;
	}

    const char *file_ext_name = fdfs_get_file_ext_name(local_filename);

    result = storage_upload_by_filebuff1(pTrackerServer,  \
			&storageServer, store_path_index, \
			buf, fileSize, file_ext_name, \
			NULL, 0, group_name, file_id);
    // 开始上传文件
	// result = storage_upload_by_filename1(pTrackerServer, \
	// 		&storageServer, store_path_index, \
	// 		local_filename, NULL, \
	// 		NULL, 0, group_name, file_id);
	if (result == 0)
	{
		printf("%s\n", file_id);
	}
	else
	{
		fprintf(stderr, "upload file fail, " \
			"error no: %d, error info: %s\n", \
			result, STRERROR(result));
	}

	tracker_close_connection_ex(pTrackerServer, true);
	fdfs_client_destroy();

	return result;
}

int main(int argc, char *argv[])
{
    char *fileName = "/home/i/images/p4.jpg";
    int fd = open(fileName, O_RDONLY);
    struct stat buf;
    fstat(fd, &buf);
    int size = buf.st_size;
    char *fileContent = malloc(size);
    read(fd, fileContent, size);
    close(fd);
	return fdfs_upload_file(fileName, "/etc/fdfs/client.conf", size, fileContent);
}