我们在pub / sub代理实现中使用boost / rapidxml进行XML解析，对于某个XML有效负载，代理崩溃了。
为了消除尽可能多的变量，我实现了一个只执行XML解析的简短测试程序，崩溃类似。
我的简短测试程序在这里找到：
#include <stdio.h> // printf
#include <unistd.h> // read
#include <sys/types.h> // open
#include <sys/stat.h> // open
#include <fcntl.h> // open
#include <errno.h> // errno
#include <string.h> // strerror
#include "rapidxml.hpp"
#ifdef LONG_RAPIDXML_NAME_SPACE
// boost version >= 1.45
using namespace boost::property_tree::detail::rapidxml;
#else
// boost version <= 1.44
using namespace rapidxml;
#endif
/* ****************************************************************************
*
* xmlTreePresent -
*/
static void xmlTreePresent(xml_node<>* nodeP, std::string indent, int depth = 0)
{
static int callNo = 0;
++callNo;
if(nodeP == NULL)
{
printf("%sNULL NODE\n", indent.c_str());
}
char* name = nodeP->name();
char* value = nodeP->value();
printf("%s%s (%s) (call %d, depth %d)\n", indent.c_str(), name, value, callNo, depth);
xml_node<>* child = nodeP->first_node();
while(child != NULL)
{
printf("%schild at %p\n", indent.c_str(), child);
printf("%schild->name() at %p\n", indent.c_str(), child->name());
if((child->name() != NULL) && (child->name()[0] != 0))
{
xmlTreePresent(child, indent + " ", depth + 1);
}
child = child->next_sibling();
}
}
/* ****************************************************************************
*
* xmlDocPrepare -
*/
static xml_node<>* xmlDocPrepare(char* xml)
{
xml_document<> doc;
try
{
doc.parse<0>(xml);
}
catch(parse_error& e)
{
printf("PARSE ERROR: %s\n", e.what());
return NULL;
}
catch(...)
{
printf("GENERIC ERROR during doc.parse\n");
return NULL;
}
xml_node<>* father = doc.first_node();
return father;
}
/* ****************************************************************************
*
* main -
*/
int main(int argC, char* argV[])
{
char* fileName = argV[1];
int fd;
if((fd = open(fileName, O_RDONLY)) == -1)
{
printf("open('%s'): %s", fileName, strerror(errno));
exit(1);
}
struct stat statBuf;
if(stat(fileName, &statBuf) != 0)
{
printf("stat('%s'): %s", fileName, strerror(errno));
exit(2);
}
char* buf = (char*) calloc(1, statBuf.st_size + 1);
if(buf == NULL)
{
printf("calloc(%lu): %s", statBuf.st_size + 1, strerror(errno));
exit(3);
}
int nb = read(fd, buf, statBuf.st_size);
if(nb == -1)
{
printf("read('%s'): %s", fileName, strerror(errno));
exit(4);
}
else if(nb != statBuf.st_size)
{
printf("read %d characters, wanted %lu", nb, statBuf.st_size);
exit(5);
}
xml_node<>* father = xmlDocPrepare((char*) buf);
xmlTreePresent(father, "");
return 0;
}
示例输入XML位于：http://pastebin.com/rYiDjP7E
我在Ubuntu（libboost_serialization.so.1.49.0）和in中都试过了 CentOS（libboost_serialization.so.5）和我有类似的崩溃。
[我不确定，但我认为boost属性树位于序列化库中......]
它在CentOS中稍微进一步，但最终会发生类似的崩溃。
感谢这里的帮助，我们让用户等待修复......
答案 0 :(得分：6)
首先关闭。
这不是c ++！用
替换整个main
int main(int argc, char* argv[])
{
std::ifstream ifs(argc>1? argv[1] : "input.txt");
std::string buf(std::istreambuf_iterator<char>(ifs), {});
xml_node<>* father = xmlDocPrepare(&buf[0]);
xmlTreePresent(father, "");
}
rapidxml不是Boost的一部分。它在Boost Property Tree中使用（实现细节）
真正的错误在于：
static xml_node<>* xmlDocPrepare(char* xml)
{
xml_document<> doc;
..
xml_node<>* father = doc.first_node();
return father;
}
这会返回对（ into ）本地的引用，但是本地（doc）在return语句之外不存在！我将按如下方式修复此实例：
int main(int argc, char* argv[])
{
std::ifstream ifs(argc>1? argv[1] : "input.txt");
std::string xml(std::istreambuf_iterator<char>(ifs), {});
try
{
xml_document<> doc;
doc.parse<0>(&xml[0]);
xmlTreePresent(doc.first_node());
return 0;
}
catch(parse_error& e) { printf("PARSE ERROR: %s\n", e.what()); }
catch(...) { printf("GENERIC ERROR during doc.parse\n"); }
return 1;
}
请注意我将76行代码减少为17行 :)并减少内存泄漏。
更新这是一个完全清理的版本--HURRAY - c ++而不是C：see it Live On Coliru，可以看到解析示例XML，但删除了可忽略的空格，这样你就可以了更好地看到输出。
当然，它也适用于'漂亮'的xml。
#include <fstream>
#include <iostream>
#include <iomanip>
#include <boost/property_tree/detail/rapidxml.hpp>
using namespace boost::property_tree::detail::rapidxml;
static void xmlTreePresent(xml_node<> const* nodeP, int depth = 0)
{
static int callNo = 0;
callNo += 1;
if(nodeP)
{
std::cout << std::setw(depth*2) << "" << nodeP->name()/* << " (" << nodeP->value() << ") (call " << callNo << ", depth " << depth << ")" */ << "\n";
for (xml_node<>* child = nodeP->first_node(); child; child = child->next_sibling())
{
auto name = child->name();
if(name && name[0])
{
xmlTreePresent(child, depth + 1);
}
}
} else
{
std::cout << std::setw(depth*2) << "" << "NULL NODE\n";
}
}
int main(int argc, char* argv[])
{
std::ifstream ifs(argc>1? argv[1] : "input.txt");
std::string xml(std::istreambuf_iterator<char>(ifs), {});
try
{
xml_document<> doc;
doc.parse<0>(&xml[0]);
xmlTreePresent(doc.first_node());
return 0;
}
catch(parse_error& e) { printf("PARSE ERROR: %s\n", e.what()); }
catch(...) { printf("GENERIC ERROR during doc.parse\n"); }
return 1;
}
这是删除了调试信息的输出（如/ 注释 /中所示）：
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