使用 MariaDB c++ 连接器和正则表达式时发生段错误
Segfault Occurs when using MariaDB c++ connector and regex
我正在构建一个查询 mysql 数据库的简单实用程序，并使用正则表达式来隔离 table 数据中的字符串。
我正在使用 MariaDB c++/connector 和最新版本的 MariaDB。该代码是从 MariaDB 网站复制的。我已经简化了软件来说明问题。见下文：
// g++ -o mariadb_connect mariadb_connect.cpp -lmariadbcpp
// From https://mariadb.com/docs/clients/connector-cpp/
// with three additional lines that cause segfault
#include <iostream>
#include <mariadb/conncpp.hpp>
#include <regex> // <-- Added to the example
int main()
{
try
{
// Instantiate Driver
sql::Driver* driver = sql::mariadb::get_driver_instance();
// Configure Connection
// The URL or TCP connection string format is
// ``jdbc:mariadb://host:port/database``.
sql::SQLString url("jdbc:mariadb://localhost:3306/??????");
// Use a properties map for the user name and password
sql::Properties properties({
{"user", "???????"},
{"password", "????????"}
});
// Establish Connection
// Use a smart pointer for extra safety
std::unique_ptr<sql::Connection> conn(driver->connect(url, properties));
// Use Connection
std::cout << "Using the connection" << std::endl; // <-- Added
std::regex regexp("(faststatic.com)(.*)"); // <-- Added (Causes segfault)
// Close Connection
conn->close();
}
// Catch Exceptions
catch (sql::SQLException& e)
{
std::cout << "Error Connecting to MariaDB Platform: "
<< e.what() << std::endl;
// Exit (Failed)
return 1;
}
// Exit (Success)
return 0;
}
(????用于隐私数据)
在 AWS EC2 实例上使用 g++ 编译 运行 Amazon Linux 2 AMI。
在我添加 std::regex regexp(...) 之前，编译和运行都很好
线。它仍然可以通过添加进行编译，但是在执行调用时
段错误。
我使用了 gdb，它提供了以下带有断点设置的输出
到主要。
(gdb) b main
Breakpoint 1 at 0x40404b: file mariadb_connect.cpp, line 15.
(gdb) run
Starting program: /home/msellers/proj/preload_images/spike/mariadb_connect
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Program received signal SIGSEGV, Segmentation fault.
0x000000000064a588 in ?? ()
这是段错误后 gdb bt 命令的输出：
(gdb) bt
#0 0x000000000064a588 in ?? ()
#1 0x0000000000409155 in std::__detail::_Scanner<char>::_M_scan_normal (this=0x7fffffffe018) at /usr/include/c++/7/bits/regex_scanner.tcc:119
#2 0x00000000004084a1 in std::__detail::_Scanner<char>::_M_advance (this=0x7fffffffe018) at /usr/include/c++/7/bits/regex_scanner.tcc:80
#3 0x00007ffff7c3e060 in std::__detail::_Compiler<std::regex_traits<char> >::_M_match_token (this=this@entry=0x7fffffffe000, token=std::__detail::_ScannerBase::_S_token_subexpr_begin) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:541
#4 0x00007ffff7c513a2 in std::__detail::_Compiler<std::regex_traits<char> >::_M_match_token (token=std::__detail::_ScannerBase::_S_token_subexpr_begin, this=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:316
#5 std::__detail::_Compiler<std::regex_traits<char> >::_M_atom (this=this@entry=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:326
#6 0x00007ffff7c515b0 in std::__detail::_Compiler<std::regex_traits<char> >::_M_term (this=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:136
#7 std::__detail::_Compiler<std::regex_traits<char> >::_M_alternative (this=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:118
#8 0x00007ffff7c51809 in std::__detail::_Compiler<std::regex_traits<char> >::_M_disjunction (this=this@entry=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:97
#9 0x00007ffff7c51e18 in std::__detail::_Compiler<std::regex_traits<char> >::_Compiler (this=0x7fffffffe000, __b=<optimized out>, __e=<optimized out>, __traits=..., __flags=<optimized out>)
at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:82
#10 0x00007ffff7c5222d in std::__detail::__compile_nfa<std::regex_traits<char> > (__first=<optimized out>, __last=<optimized out>, __traits=..., __flags=<optimized out>) at /usr/local/include/c++/4.9.4/bits/regex_compiler.h:158
#11 0x00007ffff7c524da in std::basic_regex<char, std::regex_traits<char> >::basic_regex<char const*> (__f=<optimized out>, __last=<optimized out>, __first=<optimized out>, this=0x7ffff7dc2a40 <sql::mariadb::UrlParser::URL_PARAMETER>)
at /usr/local/include/c++/4.9.4/bits/regex.h:540
#12 std::basic_regex<char, std::regex_traits<char> >::basic_regex (this=0x7ffff7dc2a40 <sql::mariadb::UrlParser::URL_PARAMETER>, __p=<optimized out>, __f=<optimized out>) at /usr/local/include/c++/4.9.4/bits/regex.h:452
#13 0x00007ffff7c331ee in __static_initialization_and_destruction_0 (__initialize_p=1, __priority=65535) at /home/buildbot/src/src/UrlParser.cpp:34
#14 _GLOBAL__sub_I_UrlParser.cpp(void) () at /home/buildbot/src/src/UrlParser.cpp:444
#15 0x00007ffff7de7dc2 in call_init (l=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7fffffffe2b8, env=env@entry=0x7fffffffe2c8) at dl-init.c:72
#16 0x00007ffff7de7eb6 in call_init (env=0x7fffffffe2c8, argv=0x7fffffffe2b8, argc=1, l=<optimized out>) at dl-init.c:119
#17 _dl_init (main_map=0x7ffff7ffe130, argc=1, argv=0x7fffffffe2b8, env=0x7fffffffe2c8) at dl-init.c:120
#18 0x00007ffff7dd9f2a in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
#19 0x0000000000000001 in ?? ()
#20 0x00007fffffffe520 in ?? ()
#21 0x0000000000000000 in ?? ()
(gdb)
这有帮助吗？
马克
GCC version 7.3.1
在回溯中，我们看到崩溃发生在 GCC-7 regexp 实现中：
#1 0x0000000000409155 in std::__detail::_Scanner<char>::_M_scan_normal (this=0x7fffffffe018) at /usr/include/c++/7/bits/regex_scanner.tcc:119
我们也看到当某些全局内部（大概1）MariaDB 连接器正在初始化时发生此崩溃，同时使用GCC-4.9.4版本libstdc++:
#12 std::basic_regex<char, std::regex_traits<char> >::basic_regex (this=0x7ffff7dc2a40 <sql::mariadb::UrlParser::URL_PARAMETER>, __p=<optimized out>, __f=<optimized out>) at /usr/local/include/c++/4.9.4/bits/regex.h:452
#13 0x00007ffff7c331ee in __static_initialization_and_destruction_0 (__initialize_p=1, __priority=65535) at /home/buildbot/src/src/UrlParser.cpp:34
极度 4.9.4 与 7.3.1 的不匹配很可能是导致崩溃的原因，并且要么使用 g++-4.9.4 构建应用程序，要么使用 g++-7.3.1 构建 MariaDB 将解决问题。
理论上libstdc++的GCC版本应该是向后兼容的，但是在C++中验证ABI兼容性是相当困难的，并且已经犯了很多错误。另外，g++4.9.4 是 ancient.
另一种可能的解决方案是使用 libc++ 构建具有 clang 的应用程序——这将避免任何可能的符号冲突2.
1 您可以通过执行这些 GDB 命令来验证帧 #13 是否真的来自 MariaDB：frame 13、info symbol $pc。
2 要实现这一点，您可能需要 明确地 告诉 clang 使用 libc++，因为它可能默认使用 libstdc++。使用 clang++ -stdlib=libc++ ... 来确定。文档 here.
我正在构建一个查询 mysql 数据库的简单实用程序，并使用正则表达式来隔离 table 数据中的字符串。
我正在使用 MariaDB c++/connector 和最新版本的 MariaDB。该代码是从 MariaDB 网站复制的。我已经简化了软件来说明问题。见下文：
// g++ -o mariadb_connect mariadb_connect.cpp -lmariadbcpp
// From https://mariadb.com/docs/clients/connector-cpp/
// with three additional lines that cause segfault
#include <iostream>
#include <mariadb/conncpp.hpp>
#include <regex> // <-- Added to the example
int main()
{
try
{
// Instantiate Driver
sql::Driver* driver = sql::mariadb::get_driver_instance();
// Configure Connection
// The URL or TCP connection string format is
// ``jdbc:mariadb://host:port/database``.
sql::SQLString url("jdbc:mariadb://localhost:3306/??????");
// Use a properties map for the user name and password
sql::Properties properties({
{"user", "???????"},
{"password", "????????"}
});
// Establish Connection
// Use a smart pointer for extra safety
std::unique_ptr<sql::Connection> conn(driver->connect(url, properties));
// Use Connection
std::cout << "Using the connection" << std::endl; // <-- Added
std::regex regexp("(faststatic.com)(.*)"); // <-- Added (Causes segfault)
// Close Connection
conn->close();
}
// Catch Exceptions
catch (sql::SQLException& e)
{
std::cout << "Error Connecting to MariaDB Platform: "
<< e.what() << std::endl;
// Exit (Failed)
return 1;
}
// Exit (Success)
return 0;
}
(????用于隐私数据)
在 AWS EC2 实例上使用 g++ 编译 运行 Amazon Linux 2 AMI。
在我添加 std::regex regexp(...) 之前，编译和运行都很好 线。它仍然可以通过添加进行编译，但是在执行调用时 段错误。
我使用了 gdb，它提供了以下带有断点设置的输出 到主要。
(gdb) b main
Breakpoint 1 at 0x40404b: file mariadb_connect.cpp, line 15.
(gdb) run
Starting program: /home/msellers/proj/preload_images/spike/mariadb_connect
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Program received signal SIGSEGV, Segmentation fault.
0x000000000064a588 in ?? ()
这是段错误后 gdb bt 命令的输出：
(gdb) bt
#0 0x000000000064a588 in ?? ()
#1 0x0000000000409155 in std::__detail::_Scanner<char>::_M_scan_normal (this=0x7fffffffe018) at /usr/include/c++/7/bits/regex_scanner.tcc:119
#2 0x00000000004084a1 in std::__detail::_Scanner<char>::_M_advance (this=0x7fffffffe018) at /usr/include/c++/7/bits/regex_scanner.tcc:80
#3 0x00007ffff7c3e060 in std::__detail::_Compiler<std::regex_traits<char> >::_M_match_token (this=this@entry=0x7fffffffe000, token=std::__detail::_ScannerBase::_S_token_subexpr_begin) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:541
#4 0x00007ffff7c513a2 in std::__detail::_Compiler<std::regex_traits<char> >::_M_match_token (token=std::__detail::_ScannerBase::_S_token_subexpr_begin, this=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:316
#5 std::__detail::_Compiler<std::regex_traits<char> >::_M_atom (this=this@entry=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:326
#6 0x00007ffff7c515b0 in std::__detail::_Compiler<std::regex_traits<char> >::_M_term (this=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:136
#7 std::__detail::_Compiler<std::regex_traits<char> >::_M_alternative (this=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:118
#8 0x00007ffff7c51809 in std::__detail::_Compiler<std::regex_traits<char> >::_M_disjunction (this=this@entry=0x7fffffffe000) at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:97
#9 0x00007ffff7c51e18 in std::__detail::_Compiler<std::regex_traits<char> >::_Compiler (this=0x7fffffffe000, __b=<optimized out>, __e=<optimized out>, __traits=..., __flags=<optimized out>)
at /usr/local/include/c++/4.9.4/bits/regex_compiler.tcc:82
#10 0x00007ffff7c5222d in std::__detail::__compile_nfa<std::regex_traits<char> > (__first=<optimized out>, __last=<optimized out>, __traits=..., __flags=<optimized out>) at /usr/local/include/c++/4.9.4/bits/regex_compiler.h:158
#11 0x00007ffff7c524da in std::basic_regex<char, std::regex_traits<char> >::basic_regex<char const*> (__f=<optimized out>, __last=<optimized out>, __first=<optimized out>, this=0x7ffff7dc2a40 <sql::mariadb::UrlParser::URL_PARAMETER>)
at /usr/local/include/c++/4.9.4/bits/regex.h:540
#12 std::basic_regex<char, std::regex_traits<char> >::basic_regex (this=0x7ffff7dc2a40 <sql::mariadb::UrlParser::URL_PARAMETER>, __p=<optimized out>, __f=<optimized out>) at /usr/local/include/c++/4.9.4/bits/regex.h:452
#13 0x00007ffff7c331ee in __static_initialization_and_destruction_0 (__initialize_p=1, __priority=65535) at /home/buildbot/src/src/UrlParser.cpp:34
#14 _GLOBAL__sub_I_UrlParser.cpp(void) () at /home/buildbot/src/src/UrlParser.cpp:444
#15 0x00007ffff7de7dc2 in call_init (l=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7fffffffe2b8, env=env@entry=0x7fffffffe2c8) at dl-init.c:72
#16 0x00007ffff7de7eb6 in call_init (env=0x7fffffffe2c8, argv=0x7fffffffe2b8, argc=1, l=<optimized out>) at dl-init.c:119
#17 _dl_init (main_map=0x7ffff7ffe130, argc=1, argv=0x7fffffffe2b8, env=0x7fffffffe2c8) at dl-init.c:120
#18 0x00007ffff7dd9f2a in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
#19 0x0000000000000001 in ?? ()
#20 0x00007fffffffe520 in ?? ()
#21 0x0000000000000000 in ?? ()
(gdb)
这有帮助吗？
马克
GCC version 7.3.1
在回溯中，我们看到崩溃发生在 GCC-7 regexp 实现中：
#1 0x0000000000409155 in std::__detail::_Scanner<char>::_M_scan_normal (this=0x7fffffffe018) at /usr/include/c++/7/bits/regex_scanner.tcc:119
我们也看到当某些全局内部（大概1）MariaDB 连接器正在初始化时发生此崩溃，同时使用GCC-4.9.4版本libstdc++:
#12 std::basic_regex<char, std::regex_traits<char> >::basic_regex (this=0x7ffff7dc2a40 <sql::mariadb::UrlParser::URL_PARAMETER>, __p=<optimized out>, __f=<optimized out>) at /usr/local/include/c++/4.9.4/bits/regex.h:452
#13 0x00007ffff7c331ee in __static_initialization_and_destruction_0 (__initialize_p=1, __priority=65535) at /home/buildbot/src/src/UrlParser.cpp:34
极度 4.9.4 与 7.3.1 的不匹配很可能是导致崩溃的原因，并且要么使用 g++-4.9.4 构建应用程序，要么使用 g++-7.3.1 构建 MariaDB 将解决问题。
理论上libstdc++的GCC版本应该是向后兼容的，但是在C++中验证ABI兼容性是相当困难的，并且已经犯了很多错误。另外，g++4.9.4 是 ancient.
另一种可能的解决方案是使用 libc++ 构建具有 clang 的应用程序——这将避免任何可能的符号冲突2.
1 您可以通过执行这些 GDB 命令来验证帧 #13 是否真的来自 MariaDB：frame 13、info symbol $pc。
2 要实现这一点，您可能需要 明确地 告诉 clang 使用 libc++，因为它可能默认使用 libstdc++。使用 clang++ -stdlib=libc++ ... 来确定。文档 here.