OpenSSL SSL_shutdown收到信号SIGPIPE，管道破裂

OpenSSL SSL_shutdown received signal SIGPIPE, Broken pipe

本文关键字：SIGPIPE 管道 信号 SSL shutdown OpenSSL      更新时间：2023-10-16

我正在使用openssl-0.9.8e编写http/https客户端

调用SSL_read()

时出现错误

然后，我调用SSL_get_error得到SSL_ERROR_SYSCALL和errno ECONNRESET 104 /* Connection reset by peer */

根据SSL文档这就是它的意思:

 SSL_ERROR_SYSCALL
 Some I/O error occurred. The OpenSSL error queue may contain more information on the error. 
If the error queue is empty (i.e. ERR_get_error() returns 0), ret can be used to find out more about the
    error: If ret == 0, an EOF was observed that violates the protocol. If ret == -1, the underlying BIO
    reported an I/O error (for socket I/O on Unix systems, consult errno for details).

好，连接重置，我调用SSL_shutdown关闭连接，哦，Program received signal SIGPIPE, Broken pipe.

天哪，我调用signal(SIGPIPE, SIG_IGN);来忽略"SIGPIPE"信号，但它似乎不起作用~

出现分段故障

#0  0x00000032bd00d96b in write () from /lib64/libpthread.so.0
#1  0x0000003add478367 in ?? () from /lib64/libcrypto.so.6
#2  0x0000003add4766fe in BIO_write () from /lib64/libcrypto.so.6
#3  0x0000003add8208fd in ssl3_write_pending () from /lib64/libssl.so.6
#4  0x0000003add820d9a in ssl3_dispatch_alert () from /lib64/libssl.so.6
#5  0x0000003add81e982 in ssl3_shutdown () from /lib64/libssl.so.6
#6  0x00000000004565d0 in CWsPollUrl::SSLClear (this=<value optimized out>, ctx=0x2aaab804a1b0, ssl=0x2aaab804a680)
    at ../src/Wspoll.cpp:1122
#7  0x00000000004575e0 in CWsPollUrl::asyncEventDelete (this=0x4d422e50, eev=0x2aaab8001160) at ../src/Wspoll.cpp:1546
#8  0x000000000045928a in CWsPollUrl::onFail (this=0x4d422e50, eev=0x2aaab8001160, errorCode=4) at ../src/Wspoll.cpp:1523
#9  0x000000000045ab17 in CWsPollUrl::handleData (this=0x4d422e50, eev=0x2aaab8001160, len=<value optimized out>) at ../src/Wspoll.cpp:1259
#10 0x000000000045abcc in CWsPollUrl::asyncRecvEvent (this=0x4d422e50, fd=<value optimized out>, eev=0x2aaab8001160)
    at ../src/Wspoll.cpp:1211
#11 0x00000000004636b5 in event_base_loop (base=0x14768360, flags=0) at event.c:1350
#12 0x0000000000456a62 in CWsPollUrl::run (this=<value optimized out>, param=<value optimized out>) at ../src/Wspoll.cpp:461
#13 0x0000000000436c5c in doPollUrl (data=<value optimized out>, user_data=<value optimized out>) at ../src/PollStrategy.cpp:151
#14 0x00000032bf44a95d in ?? () from /lib64/libglib-2.0.so.0
#15 0x00000032bf448e04 in ?? () from /lib64/libglib-2.0.so.0
#16 0x00000032bd00677d in start_thread () from /lib64/libpthread.so.0
#17 0x00000032bc4d3c1d in clone () from /lib64/libc.so.6
为什么我得到SIGPIPE信号，我已经调用了signal(SIGPIPE, SIG_IGN);有人知道为什么吗?

Thanks in advance

如果您使用SSL_read获得I/O错误，那么调用SSL_shutdown没有多大意义，因为关闭尝试向对等端发送"close notify"关闭警报，这显然不会在断开的连接上工作。因此你得到SIGPIPE或EPIPE。在这种情况下，从SSL_read获取ECONNRESET可能意味着客户端已经硬关闭了连接，例如，没有执行SSL_shutdown。在出现错误后，您不应该继续使用套接字，例如，甚至不执行SSL_shutdown。

除了@SteffenUllrich答案之外，您还可以在调用SSL_shutdown之前调用SSL_get_shutdown并检查SSL_SENT_SHUTDOWN标志是否已经设置。你可以这样做:

    //Perform a mutex lock here
    if(SSL_get_shutdown(ssl) & SSL_SENT_SHUTDOWN)
    {
        printf("shutdown request ignoredn");
    }
    else
    {
        SSL_shutdown(con->tls.openssl);
    }
    //Perform a mutex unlock here

在多个线程共享SSL *指针的多线程程序中，可能会发生SSL_shutdown已经被另一个线程调用的情况，这段代码可以保护您免受SIGPIPE信号的影响。

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